Fluid Exchange Research Articles

Energy and exergy analyses of a two-stage organic rankine cycle with low pressure stage regeneration for IC engine waste heat recovery

A two-stage Organic Rankine Cycle (ORC) with Low Pressure Stage Regeneration (LPSR) proposed in this article is intended to utilize the engine coolant energy completely for vaporization of organic fluid in a Low Pressure stage Heat Exchanger (LPHE) and the engine exhaust energy for sensible heating, vaporization and super heating of organic fluid in a High Pressure stage Heat Exchanger (HPHE) besides utilizing the superheated vapor energy of exhaust from Low Pressure stage Turbine (LPT) in a regenerator. Since regeneration is used only at low pressure stage, the energy associated with the engine exhaust gases can be utilized to the maximum extent by lowering its temperature nearer to the temperature of liquid phase working fluid after High Pressure stage Pump (HPP), thereby maximizing the Waste Heat Recovery (WHR) potential of the bottoming two stage ORC. The WHR efficiency of two-stage ORC with and without LPSR is analyzed at a typical operating condition of the engine using a nearly dry fluid R123 and a nearly isentropic fluid R134a as the working substances. It is observed that the thermal efficiency of the two-stage ORC with R123 is higher than that with R134a. The LP stage regeneration has been found to be effective in increasing the thermal efficiency and, in turn, the WHR efficiency of the two-stage ORC with both R123 and R134a. The increase in the fuel efficiency of the IC engine due to the bottoming two-stage ORC is found to be 7.22% with R123 and 6.21% with R134a with LPSR and 6.58% with R123 and 5.51% with R134a without LPSR. The optimum pressure in HPHE is found to be about 2.5 MPa and 3.5 MPa with R123 and R134a respectively.

The Extrauterine Environment for Neonatal Development Supports Mid-Gestation Fetal Lambs

INTRODUCTION: Extreme prematurity remains the leading cause of morbidity and mortality in pediatrics. The Extrauterine Environment for Neonatal Development (EXTEND) has previously been reported to sustain lambs at >105 days gestational age (GA), which is equivalent for lung development to a 23- to 24-week human fetus, for up to 28 days. However, to assess the risk for intraventricular hemorrhage on EXTEND, an earlier gestation model is required. The 85- to 95-day GA lamb has brain development and size equivalence to the 23- to 24-week human fetus. Previous studies at this age were limited by an inability to sustain animals for >7 days due to physiologic derangements. METHODS: Fetal lambs between 90 and 95 days GA underwent umbilical vascular cannulation onto a pumpless membrane oxygenator circuit and were delivered into a closed, fluid environment with continuous “amniotic” fluid exchange. Lambs were monitored for circuit blood flow, heart rate, and oxygenation, with more aggressive flow, hematocrit, and nutrition management than in the previous 85- to 95-day GA studies. RESULTS: Of 23 attempts at cannulation, 14 (61%) transitioned successfully to EXTEND with physiologic flows (Fig.1A, n = 14), heart rate (Fig.1B, n = 14), and oxygen delivery (Fig.1C, n = 5). Animals gained an average 64% body weight and appeared to develop normally (Fig.1D). Of those cannulated, 10 completed a 10- to 21-day run, one died of an embolic cardiac arrest (day 6), 2 died of an intractable venous spasm (days 7and 8), and 1 died due to human error (day 3).Figure 1CONCLUSION: This work demonstrates that EXTEND can provide prolonged support of fetal lambs with neurodevelopmental equivalence to extremely premature human fetuses.

Massive growth of a fibrous gas hydrate from surface macropores of an activated carbon

Venet et al., reported unprecedented, bundled growth of ≈ 1-10mm long, hollow gas hydrate fibres, diameter ≈ 1-10μm, on an activated carbon close to a guest-water interface, circumventing the hydrate growth bottleneck. Here, in situ video microscopy traces growth (2-3μms-1 at 0.5°C) to surface macropores of similar diameter, further exhibited by confocal and scanning electron microscopies. X-ray radiography shows fluid exchange to a depth of ≈ 50-100μm in a total porous fraction 40% (gravimetric porometry). Computed X-ray microtomography reveals a belt of organised peripheral porosity of aligned ≈5μm pores. These structures explain the origin of the comb or whalebone-like appearance of the hydrate. Whereas hydrate promotion by porous media is usually assumed to proceed inside the materials, like tiny hydrate storage warehouses, we find that the substrate behaves more like a ’lean’ or ’just in time’ production line, with hydrate extruded as fast as it is produced near the surface.

Characteristics of Babies Born to HIV Positive Mothers in Ulin General Hospital Banjarmasin January – December 2020

The high incidence rate of mothers with Human Immunodeficiency Virus (HIV) increases the potential of vertical transmission to the baby. HIV is a group of retroviruses that attacks the immune system. It can be transmitted through the exchange of various body fluids from the infected person, such as blood, breast milk, semen, and vaginal fluids. HIV can also be passed from a mother to her child during pregnancy and childbirth. Transmission of HIV from mother to baby is called a vertical transmission and may occur in 3 ways, including antenatal, perinatal, and postnatal (breast milk). This study aims to describe the characteristics of babies born to HIV positive mothers at Ulin General Hospital, Banjarmasin during January-December 2020. This is a descriptive observational study using secondary data from medical records of the babies born to HIV mothers at Ulin General Hospital, Banjarmasin. We include 13 cases of babies born to HIV-positive mothers. The characteristics of the babies were male (53.8%), born without asphyxia (92%), has normal birth weight (84.6%), full-term (92%), and 84.6% of babies were delivered through C-section. The results showed that it is necessary to work together with various fields to get early intervention for each baby.

Aspect-ratio dependence of heat and angular momentum transport in turbulent Taylor-Couette flows with axial thermal forcing

• Scaling law of transports determined in finite systems can be extrapolated to large-scale flows. • Coherent turbulent structures in form of Taylor vortices promote heat and angular transports. • Magnitudes of both heat and angular momentum transport depend on domain aspect-ratio. We report numerical studies of the effects of geometry factors, i.e. the aspect ratio Γ and radius ratio η , on the axial heat transport N u and the radial angular momentum transport N ω by turbulent Taylor-Couette flows that are subjected to a vertically destabilizing temperature gradient. For a given Reynolds number R e the magnitudes of both N u and N ω exhibit a pronounced aspect-ratio dependence. The angular momentum transport is reduced in long cylinders, since endwall effects are weakened as Γ increases. For the heat transfer in large- Γ cylinders, a significant N u -reduction appears for low- R e regime, whereas N u can be greatly enhanced in the regime of turbulent Taylor vortex (TV). The former N u -reduction is associated with the process that the thermal plumes are swept away by the Ekman vortices near the boundaries, and the fluid exchange is severely restricted between adjacent vortices in the bulk region. The latter N u -enhancement is attributed to the strengthened shears arising in large- Γ cylinders, resulting in a more turbulent boundary layer. Moreover, the pronounced inter-mixing of turbulent TVs continuously pumps the hot (cold) fluids into the bulk, intensifying the transport processes. It is found that although the constraints from the endwalls impact the global heat and angular momentum transport in the low- R e regime, they hardly affect their scaling properties in the high- R e regime with large Γ . We thus expect that the scaling relationship of N u ( R e ) and N ω ( R e ) determined with finite Γ can be extrapolated to large-scale, and even vertically unbounded industrial and geophysical flows.

The inclination of magnetic dipole effect and nanoscale exchange of heat of the Cross nanofluid

Nanoscale energy exchange and movement of fluid by Lorentz force is the most recent problem that has a strong connection with applied mathematics due to the consumption of energy. Imposing the inclination of Magnetic dipole in the fluid has abundant applications in magnetic drug engineering, astrophysics, sensors, geophysics, cosmology, and targeting. This study is associated with the exchange of energy under the influence of the inclination of Magnetic dipole with cylinder geometry. The Cross nanofluid mathematical model is launched to carry the nanoscale energy exchange with temperature-dependent thermal conductivity. The permeable cylinder geometry along with the different effects is provided during the expanding/contracting cylinder. Whereas Cross fluid helps to investigate the problem in shear thinning/thickening regions. The numerical representations of the problem are provided via the BVP4C scheme.

Enlarged perivascular spaces, neuroinflammation and neurological dysfunction in NMOSD patients.

Background and objectivesCerebrospinal fluid (CSF) and interstitial fluid exchange along a brain-wide network of perivascular spaces (PVS) termed the ‘glymphatic system’. The aquaporin-4 (AQP4) water channels abundantly expressed on astrocytic endfeet play a key role in the CSF circulation in the glymphatic system. Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating autoimmune disease of the central nervous system (CNS) featured with a specific autoantibody directed against AQP4 in most of patients. Anti-AQP4 antibodies are likely resulting in the impairment of the brain glymphatic system and the enlargement of PVS in NMOSD patients. In the current study, we aimed to demonstrate the features of EPVS detected by MRI and its association with the CSF anti-AQP4 antibody titer, CNS inflammatory markers, and disease severity in NMOSD patients.MethodsWe conducted a retrospective review of a consecutive cohort of 110 patients with NMOSD who had brain MRI. We assessed the correlation of EPVS with markers of neuroinflammation, blood-brain barrier (BBB) function and severity of neurological dysfunction in patients. We used multivariate logistic regression analysis to determine the independent variables associated with disease severity.ResultsThe median number of total-EPVS was 15.5 (IQR, 11-24.2) in NMOSD patients. The number of total-EPVS was significantly related to EDSS score after correcting for the effects of age and hypertension (r=0.353, p<0.001). The number of total-EPVS was also significantly associated with the titer of CSF anti-AQP4 antibody, the albumin rate (CSF/serum ratios of albumin), the CSF albumin, IgG and IgA levels. Logistic regression analysis showed that total-EPVS and serum albumin level were two independent factors to predict disease severity in NMOSD patients (OR=1.053, p=0.028; OR=0.858, p=0.009 respectively). Furthermore, ROC analysis achieved AUC of 0.736 (0.640-0.831, p<0.001) for total-EPVS to determine severe NMOSD (EDSS 4.5-9.5).DiscussionIn our cohort, we found a relationship between EPVS and neuroinflammation and BBB function in NMOSD. Moreover, EPVS might independently predict neurological dysfunction in patients with NMOSD.

Heat transfer and entropy analysis for nanofluid flow in a semi-circular open cavity under mixed convection

This paper presents a numerical simulation of nanofluid flowing in an open cavity under mixed convection by considering various heat transfer zones. To enhance the heat transfer, water was augmented with copper nanoparticles at different ϕ (volume fraction of nanoparticles) values. The present paper aims to determine the optimal position which maximizes the heat transfer in a circular open cavity. Also, in this research the investigation of combined convection flow in a specific geometry, taking into account the changes in the flow parameters, is an attempt to model the temperature field and heat transfer. For this purpose, the nanofluid flow for Reynolds numbers of Re =10, 50 and 100 is investigated. On the other hand, the hot areas in the curved part of the open cavity are separated in various cases. The results show that due to the low velocity of the fluid in the circular part of the cavity, especially in the hot wall area, most of the fluid exchange is due to natural convection due to density difference and the hot areas are strengthen the flow circulation. The exchange is also improved by increasing Re (Reynolds number) or the momentum term, and the distribution of T (temperature) in the cavity becomes more uniform. Hot spots with low heat transfer coefficient were attenuated at higher Re. The most suitable temperature distributions were achieved for W4 and W2. By increasing ϕ, the friction factor decreases for pure water, especially in W2 and W3. However, due to fluid-surface impact at Re = 100 in W2 and W3, the friction factor does not change significantly by altering ϕ. Using a higher Re and the dominance of the fluid momentum in comparison with the viscous force, the effect of nanoparticle concentration decreases. In general, the best heat transfer occurs at higher volume fraction of nanoparticles. Finally, at all Reynolds numbers, the heat transfer increases by 8–19%. This is because nanoparticles are added to pure water (working fluid).

Mechanically robust bamboo node and its hierarchically fibrous structural design.

Although short bamboo nodes function in mechanical support and fluid exchange for bamboo survival, their structures are not fully understood compared to unidirectional fibrous internodes. Here, we identify the spatial heterostructure of the bamboo node via multiscale imaging strategies and investigate its mechanical properties by multimodal mechanical tests. We find three kinds of hierarchical fiber reinforcement schemes that originate from the bamboo node, including spatially tightened interlocking, triaxial interconnected scaffolding and isotropic intertwining. These reinforcement schemes, built on porous vascular bundles, microfibers and more-refined twist-aligned nanofibers, govern the structural stability of the bamboo via hierarchical toughening. In addition, the spatial liquid transport associated with these multiscale fibers within the bamboo node is experimentally verified, which gives perceptible evidence for life-indispensable multidirectional fluid exchange. The functional integration of mechanical reinforcement and liquid transport reflects the fact that the bamboo node has opted for elaborate structural optimization rather than ingredient richness. This study will advance our understanding of biological materials and provide insight into the design of fiber-reinforced structures and biomass utilization.

Association of MRI Indices of Glymphatic System With Amyloid Deposition and Cognition in Mild Cognitive Impairment and Alzheimer Disease.

The glymphatic system is a whole-brain perivascular network, which promotes CSF/interstitial fluid exchange. Alterations to this system may play a pivotal role in amyloid β (Aβ) accumulation. However, its involvement in Alzheimer disease (AD) pathogenesis is not fully understood. Here, we investigated the changes in noninvasive MRI measurements related to the perivascular network in patients with mild cognitive impairment (MCI) and AD. Additionally, we explored the associations of MRI measures with neuropsychological score, PET standardized uptake value ratio (SUVR), and Aβ deposition. MRI measures, including perivascular space (PVS) volume fraction (PVSVF), fractional volume of free water in white matter (FW-WM), and index of diffusivity along the perivascular space (ALPS index) of patients with MCI, those with AD, and healthy controls from the Alzheimer's Disease Neuroimaging Initiative database were compared. MRI measures were also correlated with the levels of CSF biomarkers, PET SUVR, and cognitive score in the combined subcohort of patients with MCI and AD. Statistical analyses were performed with age, sex, years of education, and APOE status as confounding factors. In total, 36 patients with AD, 44 patients with MCI, and 31 healthy controls were analyzed. Patients with AD had significantly higher total, WM, and basal ganglia PVSVF (Cohen d = 1.15-1.48; p < 0.001) and FW-WM (Cohen d = 0.73; p < 0.05) and a lower ALPS index (Cohen d = 0.63; p < 0.05) than healthy controls. Meanwhile, the MCI group only showed significantly higher total (Cohen d = 0.99; p < 0.05) and WM (Cohen d = 0.91; p < 0.05) PVSVF. Low ALPS index was associated with lower CSF Aβ42 (r s = 0.41, p fdr = 0.026), FDG-PET uptake (r s = 0.54, p fdr < 0.001), and worse multiple cognitive domain deficits. High FW-WM was also associated with lower CSF Aβ42 (r s = -0.47, p fdr = 0.021) and worse cognitive performances. Our study indicates that changes in PVS-related MRI parameters occur in MCI and AD, possibly due to impairment of the glymphatic system. We also report the associations between MRI parameters and Aβ deposition, neuronal change, and cognitive impairment in AD.

Aquaporin-4 cerebrospinal fluid levels are higher in neurodegenerative dementia: looking at glymphatic system dysregulation

Aquaporin-4 (AQP4) is a channel protein that plays a fundamental role in glymphatic system, a newly described pathway for fluid exchange in the central nervous system, as well as a central figure in a fascinating new theory for the pathophysiology of neurodegenerative diseases such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD). In this study, cerebrospinal fluid (CSF) concentration of AQP4, amyloid-β, total tau and P-tau were determined in 103 CSF samples from patients affected by neurodegenerative dementias (AD and FTD) or psychiatric diseases and 21 controls. Significantly higher levels of AQP4 were found in AD and FTD patients compared to subjects not affected by neurodegenerative diseases, and a significant, positive correlation between AQP4 and total tau levels was found. This evidence may pave the way for future studies focused on the role of this channel protein in the clinical assessment of the glymphatic function and degree of neurodegeneration.

Vascular refilling coefficient is not a good marker of whole-body capillary hydraulic conductivity in hemodialysis patients: insights from a simulation study

Refilling of the vascular space through absorption of interstitial fluid by micro vessels is a crucial mechanism for maintaining hemodynamic stability during hemodialysis (HD) and allowing excess fluid to be removed from body tissues. The rate of vascular refilling depends on the imbalance between the Starling forces acting across the capillary walls as well as on their hydraulic conductivity and total surface area. Various approaches have been proposed to assess the vascular refilling process during HD, including the so-called refilling coefficient (Kr) that describes the rate of vascular refilling per changes in plasma oncotic pressure, assuming that other Starling forces and the flow of lymph remain constant during HD. Several studies have shown that Kr decreases exponentially during HD, which was attributed to a dialysis-induced decrease in the whole-body capillary hydraulic conductivity (LpS). Here, we employ a lumped-parameter mathematical model of the cardiovascular system and water and solute transport between the main body fluid compartments to assess the impact of all Starling forces and the flow of lymph on vascular refilling during HD in order to explain the reasons behind the observed intradialytic decrease in Kr. We simulated several HD sessions in a virtual patient with different blood priming procedures, ultrafiltration rates, session durations, and constant or variable levels of LpS. We show that the intradialytic decrease in Kr is not associated with a possible reduction of LpS but results from the inherent assumption that plasma oncotic pressure is the only variable Starling force during HD, whereas in fact other Starling forces, in particular the oncotic pressure of the interstitial fluid, have an important impact on the transcapillary fluid exchange during HD. We conclude that Kr is not a good marker of LpS and should not be used to guide fluid removal during HD or to assess the fluid status of dialysis patients.

Zoonotic Spillover in an Era of Rapid Deforestation of Tropical Areas and Unprecedented Wildlife Trafficking: Into the Wild

Rapid deforestation and unprecedented wildlife trafficking are important factors triggering the rate of zoonotic spillover from animals to humans. Consequently, this leads to the emergence and re-emergence of zoonotic infectious diseases among the human population. Deforestation is an important ecological disruption that leads to the loss of biodiversity. The loss of biodiversity results in the persistence of highest-quality hosts of zoonotic pathogens dominating the low-diversity communities, a process termed the dilution effect. Activities like intensive farming and logging that resulted in deforestation bring vulnerable people in close contact with these highest-quality reservoir hosts (wildlife). As a result of this vulnerability, there is an increased risk of spillover, leading to zoonotic infection in humans and eventually disease outbreaks during human–human transmission. One prominent example of a disease of wildlife origin is the ongoing SARS-CoV-2 (Severe Acute Respiratory Syndrome-Coronavirus 2), even though the original source has not been found. Another important factor facilitating the risk of spillover and emergence of zoonotic infectious diseases is wildlife trafficking. This involves illegal hunting and trading of wildlife and their products, which increases the risk of spillover as a result of exchange of bodily fluids and bloodmeals between humans and wildlife during the hunting and butchering of animals’ carcasses. Consequently, little or no hygiene protocol and poor handling practices during the wildlife-trade chain expose poachers, consumers, and local market sellers to the risk of zoonotic diseases. Despite the interventions on deforestation-induced spillover and wildlife trafficking-associated spillover, there are still knowledge and research gaps that need to be addressed towards preventing the outbreaks of future zoonotic infectious diseases. In response to this, there is a need for interdisciplinary and intersectoral collaborations among researchers from various fields as well as sectors in minimizing the risk of zoonotic spillover driven by deforestation and wildlife trafficking at the human–animal–environmental nexus. In addition, there is a need for integrated and unified evidence-based policy formulation that puts an end to deforestation and wildlife trafficking, especially in tropical areas such as Africa and Asia.

The Role of Echocardiography in Amniotic Fluid Embolism: A Case Series and Review of the Literature

(Can J Anesth/J Can Anesth. 2021;68:1541–1548) Amniotic fluid embolism (AFE) is not completely understood and can be difficult to diagnose, as it shares characteristics with other obstetric complications. AFE occurs during labor or soon after delivery and is characterized by acute hypotension, hypoxia, and coagulopathy. The Clark diagnostic criteria for diagnosis of AFE is as follows: sudden cardiorespiratory arrest or both hypotension and respiratory compromise; disseminated intravascular coagulation; clinical onset during labor or within 30 minutes of delivery of the placenta; and absence of fever. Situations that may lead to the exchange of maternal and fetal fluid, such as cesarean delivery or cervical trauma, have been reported as risk factors. Point-of-care echocardiography has recently been used to diagnose and manage maternal shock. This report details three cases of AFE that utilized point-of-care echocardiography.

Well Production Optimization under the Scale Effect and CO2-WAG Injection in a Carbonate Model of the Brazilian Pre-Salt

Summary Scale represents a risk to the profitability of projects in the oil exploration and production industry. The occurrence of the phenomenon has the potential to cause severe damage to producer and injector wells, subsea lines, and surface systems, commonly requiring the cleaning and replacement of these elements and resulting in lost profit because of reduced production efficiency, need for unscheduled maintenance stoppages, and, in the most serious cases, permanent losses of wells, lines, and equipment. The problem becomes even more severe in projects that use the injection of reactive fluids into the reservoir, as is the case with carbon dioxide-water alternating gas (CO2-WAG) injection. To avoid such an occurrence, scale inhibitors are used, which are continuously dosed at various points in the production flow, from subsea chemical injection mandrel, commonly positioned at the ends of the production columns, wet Christmas tree valves, and at various positions in the plant process on the surface. However, the regions upstream of the chemical injection mandrels, such as the perforations zone and the reservoir itself, are normally not protected by continuous-dosing inhibitors and are therefore critical for the occurrence of the phenomenon. These critical points require removal operations when the accumulation of scale is significant to economically justify a treatment. To prevent the recurrence of scale in the short term, the cleaning operation is commonly associated with the squeeze of inhibitors into the porous medium. The effect of this inhibition, however, is temporary, as the inhibitor adhered to the rock is released with the water production, until it ceases to be effective after a determined accumulated production of this fluid, requiring the evaluation of a new application of the product. This work proposes a workflow for optimizing cleaning treatments associated with scale inhibitor injection, as well as CO2-WAG fluid exchanges, aimed at protecting the reservoir and well producer perforations, and seeking to optimize the project’s net present value (NPV) in operations carried out by means of rigs or remotely by the stationary production unit (SPU). To this end, a study was carried out by coupling producer scale and inhibition proxies to a flow simulation with a reactive transport model, representative of some fields of the Brazilian pre-salt. The method developed, in addition to providing greater robustness to the predicted production curve by considering the occurrence of scale in the producer perforations, can identify optimal time windows for the treatment, even if they are in periods where the inhibition is no longer effective. The results obtained in the study for a single producing well indicate a substantial gain in the NPV with the use of the proposed methodology, around 13 million USD in relation to the proposal of treatments always carried out in a preventive way. The application also indicated that it is more advantageous to carry out remote operations through the SPU, even with lower cleaning efficiency when compared with rig treatments, with a gain of about 12 million USD.

Small-animal blood exchange is an emerging approach for systemic aging research.

We describe a small-animal blood exchange approach developed for aging research as an alternative to heterochronic parabiosis or plasma injections. In parabiosis, animals are surgically coupled, which has several disadvantages, including difficulty controlling experimental procedure, the effects of shared organs, environmental enrichment from jointly exploring the housing enclosure, involuntary exercise and an imprecise onset of blood sharing. Likewise, in plasma injections, the added volumes need to be small, and there is little flexibility in changing the relative contributions of ectopic to endogenous blood components. These factors complicate the conclusions and interpretations, including the identification of key mechanisms and molecular or cellular determinants. Our approach, where blood is exchanged between animals without them being surgically coupled, is less invasive than parabiosis. The percentage of exchanged blood or other exchanged fluids is known and precise. The age of plasma and cells can be mixed and matched at all desired relative contributions to the endogenous systemic milieu, and the onset of the effects can be accurately delineated. In this protocol, we describe the preparatory and animal surgery steps required for small-animal blood exchange in mice and compare this process with parabiosis and plasma injections. We also provide the design, hardware and software for the blood exchange device and compare automated and manual exchange methods. Lastly, we report mathematical modeling of the dilution of blood factors. The fluid exchange takes ~30 min when performed by a well-trained biomedical scientist; the entire process takes ~2 h.

Continuous Theta-Burst Stimulation Promotes Paravascular CSF-Interstitial Fluid Exchange through Regulation of Aquaporin-4 Polarization in APP/PS1 Mice.

Amyloid-β (Aβ) deposition plays a crucial role in the occurrence and development of Alzheimer's disease (AD), and impaired Aβ clearance is the leading cause of Aβ deposition. Recently, studies have found that the glymphatic system performs similar functions to the peripheral lymphatic system. Glymphatic fluid transport mainly consists of cerebrospinal fluid (CSF) entering the brain from the paravascular space (PVS) by penetrating arteries and CSF and interstitial fluid exchanging mediated by aquaporin-4 (AQP4). This system promotes the drainage of interstitial fluid (ISF) in the parenchyma and removes metabolic waste, including Aβ, in the brain. Glymphatic system dysfunction plays an essential role in the occurrence and progression of AD. Regulation of glymphatic fluid transport may be a critical target for AD therapy. This study explored the regulatory effects of continuous theta-burst stimulation (CTBS) on the glymphatic system in APPswe/PS1dE9 (APP/PS1) mice with two-photon imaging. The results demonstrated that CTBS could increase glymphatic fluid transport, especially CSF and ISF exchange, mediated by improved AQP4 polarization. In addition, the accelerated glymphatic pathway reduced Aβ deposition and enhanced spatial memory cognition. It provided new insight into the clinical prevention and treatment of Aβ deposition-related diseases.

Constraints on hydraulic properties from free pressure oscillations recorded during pumping operations in boreholes

SUMMARY Free pressure oscillations during pumping operations in boreholes may potentially constrain hydraulic characteristics of the surrounding material. These damped oscillations occur when flow rate is suddenly changed, and their period and decay rate depend on the hydraulic properties of the entire hydraulic system: the porous medium, a section of the borehole, and/or the injection line, depending on test set-up. There have been previous attempts to estimate transmissivity values from free pressure oscillations that occurred during slug tests in open boreholes. The analysis used did not account for viscous losses due to the fluid interacting with the borehole wall. In contrast, dispersion relations of flow waves in a tight borehole (i.e. a cylindrical hole in an impermeable medium) account for wall friction. We extend a previous analytical treatment of flow waves by changing the boundary condition of the fluid velocity at the borehole wall to include fluid exchange between borehole and porous medium. In addition, we performed numerical modelling of waves propagating in boreholes with impermeable and permeable walls to assess the effect of the assumptions behind the analytical solution. We established how to distinguish cases in which the flow into the porous medium affects the oscillation characteristics (suitable for a hydraulic analysis) from those in which the equipment properties dominate the observations. Applying our methods to a range of field observations yielded plausible hydraulic property values of the rock volume surrounding the borehole.

ASSOCIATION BETWEEN HUMAN IMMUNODEFICIENCY VIRUS AND MALIGNANT NEOPLASMS OF THE ORAL CAVITY: A REVIEW OF LITERATURE

<h3>Objectives</h3> The human immunodeficiency virus (HIV) is a virus transmitted through the exchange of body fluids, which can result in acquired immunodeficiency syndrome, which is associated with the etiology of oral malignancies. The aim was to evaluate the association between the etiology of oral malignant neoplasms and HIV. <h3>Study Design</h3> A survey of studies published in the previous 5 years in the PubMed database was conducted using the keywords "oral neoplasm, oral cancer, acquired immunodeficiency virus, HIV, human immunodeficiency syndrome and AIDS." <h3>Results</h3> 85 articles were found in PubMed. Only 9 studies remained after the selection. The mean age of the patients was 36.8 years with a predilection for males (5/4). The most prevalent neoplasms were non-Hodgkin's lymphoma (n = 3) and Kaposi's sarcoma (n = 3). The most common locations were alveolar ridge and hard palate. The therapeutic approaches were diverse and frequently included the administration of antiretroviral therapy associated with surgical excision or chemotherapy. Three patients died, 5 had regression of the disease, and 1 case did not state the prognosis. <h3>Conclusions</h3> Although the literature is limited, the reported cases show the influence of HIV on the etiology of multiple malignant neoplasms, revealing the significance of early diagnosis to the positive prognosis.

Characteristics of the Rongcheng Bulge Geothermal Field and the Evolution of Geothermal Fluids, Xiong’an New Area, China

The study of geothermal field characteristics and the mechanisms involved in the hydrogeochemical evolution of geothermal fluids is an effective means to understand the formation, reservoir conditions and circulation mechanics of geothermal resources. Documenting these parameters within the Rongcheng Bulge of Xiong’an New Area, China, is of great significance to its future development and utilization as a geothermal resource. In this paper, we investigate the hydrochemical characteristics of geothermal fluids and the rock thermal properties of the Rongcheng Bulge Reservoir and the surrounding rocks to identify the mechanisms of geothermal fluid genesis within the geothermal field. The results show that the geothermal water in the Rongcheng Bulge is mainly recharged by atmospheric rainfall. The thermal storage temperature at which the deep geothermal fluid is located ranges between 63 and 105 °C, whereas the depth of geothermal water circulation is between 1500 and 2700 m. Fluid exchange is weak during deep circulation, but as the geothermal fluid rises, the proportion of cold water mixed with the geothermal waters is 75–95%. The overall geothermal gradient of the carbonate thermal reservoir is significantly lower than that within the overburden and basement rocks, probably due to convection during the upward transport of groundwater in the reservoir. The geothermal fluid in the area of the Rongcheng Bulge is recharged by the Taihang Mountains and atmospheric precipitation. Following recharge and deep circulation, the fluids rise along fractures and by interlayer convection and are mixed with cold water to form the current, accessible geothermal water.