Side Of Chamber Research Articles

482-P: Behavioral Assessment of 10kHz Spinal Cord Stimulation–Mediated Pain Relief in a Rat Model of Painful Diabetic Neuropathy

Painful diabetic neuropathy (PDN) is a serious complication of diabetes and occurs in approximately 20% of diabetic patients. In a recent RCT, 10kHz spinal cord stimulation (10kHz SCS) was shown to be a promising therapy for PDN, in both pain reduction and possible neurological improvements (Petersen et al 2021). In this study, we aimed to observe the behavioral effects of 10kHz SCS on PDN using streptozotocin (STZ)-induced diabetic rats. We established four testing groups: Naïve controls, STZ controls, STZ+Sham SCS, and STZ+10kHz SCS. A single effective dose (60 mg/kg) of the cytotoxic agent STZ caused the rats to become hyperglycemic within 72 hours and lasted for several weeks. These STZ-injected rats also showed a significant and continuous reduction in body weight in comparison to Naïve control rats. Using the von Frey test for mechanical allodynia, we observed that 14 days of 24h/day low-intensity (30% of motor threshold) 10kHz SCS significantly elevated the mechanical pain withdrawal thresholds compared to STZ controls or STZ+Sham SCS animals, reaching statistical equivalence to Naïve controls. In a thermal preference assay, all animals exhibited a training effect towards less activity and more preference to the room temperature side vs the non-painful heat side of a two-temperature chamber over the several-week protocol. We found that STZ-injected animals demonstrated significantly less exploration activity in the 10min testing periods compared to Naïve controls but neither the thermal preference nor the total distance they traveled were restored after 14 days of 10kHz SCS. Our results demonstrate that 10 kHz SCS resulted in behavioral outcomes reflective of the mechanical pain reduction in the PDN rodent model. These findings provide supporting evidence for the recent RCT data and underscore the conclusion that 10kHz SCS can effectively treat patients with refractory PDN. Disclosure D.Wang: Employee; Nevro Corp. D.Lee: Employee; Nevro Corp. K.Lee: Employee; Nevro Corp. Z.B.Kagan: Employee; Nevro Corp. K.Bradley: Employee; Nevro Corp.

P256 AN UNUSUAL CASE OF PACEMAKER MALFUNCTION WITH NON COMMON ELCTROCARDIOGRAPHIC PRESENTATION AND UNEXPECTED ECHOCARDIOGRAPHIC FINDING

Abstract This clinical case shows the diagnostic challenge and the management of a 79 y–o male with recent hospitalization for infero–lateral STEMI undergoing primary PCI of Right Coronary Artery with 2 DES and following DDDR MRI PM (pacemaker) implantation due to the development of persistent 2:1 Atrio–Ventricular Block. One month later, admission at Emergency Department for syncope. Normal parameters were found at laboratory analyses. The electro–stimulator activity evaluation showed a PM malfunction with ventricular capture failure. Thus, the increase of PM output up to electric ventricular capture (8 Volt/120 msec) was performed, but the following Electrocardiogram showed a PM–induced rhythm with RBBB–morphology. Then, the bedside Echocardiogram showed an apparent presence of a linear hyper–echogenic image into left ventricle with no inter–ventricular septal defect neither inter–ventricular shunt, inter–atrial septal hypermobility with no evident inter–atrial shunt at rest; while a chest Radiography identified the atrial and ventricular leads with no accurate individuation of their position. The patient was admitted in Intensive Cardiac Care Unit with confirmation of intermittent failure to ventricular capture and RBBB–morphology during PM–induced rhythm at telemetry monitoring. Due to Electrocardiographic and Echocardiographic findings, a strong suspect of abnormal position of the ventricular lead into left ventricle through a possible PFO has been raised. A chest Computed Tomography was performed confirming the anomalous position of the ventricular lead: it reached the left atrium through an inter–atrial defect/patent foramen ovale (PFO), then crossing the mitral valve up to left ventricle. The PM–lead repositioning was scheduled two days after. After positioning of temporary stimulator lead in right ventricle, the ventricular lead has been withdrawn from left–side chambers and positioned into septal–apical right ventricle; furthermore, the position of right atrial lead has been optimized (because of frequent spontaneous passage to the left atrium through the PFO, during manual maneuvers) thus obtaining good stability of the device. During the following days, the telemetry monitoring showed a PM–induced rhythm, without capture nor sensing failure. The chest Radiography confirmed the correct position of leads and the pre–discharge Echocardiography showed a LVEF 57% with no valvular pathology and with atrial and ventricular leads into right–side chambers.

Oil cells in the side walls of air chambers, a new taxonomic character in the family Marchantiaceae

Comparative studies of oil cells in the air chamber side walls of eight Japanese taxa of Marchantiaceae showed that three morphological groups can be recognized based on this character: (1) Marchantia polymorpha and M. paleacea with conspicuous and whitish oil cells, (2) M. emarginata, M. papillata and M. pinnata with indistinct and nearly hyaline oil cells, and (3) Preissia quadrata without oil cells. This grouping is congruent with the results of existing phylogenetic analyses involving Marchantiaceae taxa. The morphology of oil cells in the side walls of air chambers should be used as a new taxonomic character within the family Marchantiaceae.

Microbial Fuel Cell Equipped with Bipolar Membrane Using Iron (III) Hydroxide as Final Electron Acceptor

In this paper, we presented a novel microbial fuel cell (bMFC) structure, with a bipolar membrane separating the anode and cathode chambers. A bipolar membrane divides the bMFC into anode and cathode chambers. The bipolar membrane comprises anion and cation exchange layers. The anode chamber side has the cation exchange layer, while the cathode chamber side has the anion exchange layer. The anode chamber of the bMFC was loaded with Shewanella oneidensis MR-1 and lactic acid, while the cathode chamber was loaded with pure water and iron (III) hydroxide. The bMFC generated electrons for 20 days at a maximum current density of 30 mA/m2 and the ohmic resistance value was estimated to be 500 Ω. During the operation of the bMFC, both the anode and cathode chambers kept anaerobic conditions. There was no platinum catalyst in the cathode chamber, which is required for the reaction of protons with oxygen. Therefore, oxygen could not serve as an electron acceptor in the bMFC. We considered a bMFC mechanism in which protons produced by S. oneidensis react with hydroxide ions, the counter anions of Fe3+, inside the bipolar membrane to produce water. In other words, the electron acceptor in bMFC would be Fe3+.

Temperature and Thermal Stress Analysis of a Hot Blast Stove with an Internal Combustion Chamber

In this study, the temperature and thermal stress fields of an internal combustion hot blast stove were calculated and analysed. Turbulent, species transport, chemical reaction, radiation, and porous media models were implemented in a computational fluid dynamics model. Thermal boundary conditions on the structure of the hot blast stove were calculated based on the analytic adiabatic Y-plus method. A method to interpolate the thermal boundary conditions to a finite element mesh was developed, and the boundary conditions were mapped through the proposed method. In the on-gas period, the vortex was generated in the dome, and it made the variation of the temperature field in the checker chamber. The maximum temperature of the flue gas reached 1841 K in the on-gas period. In the on-blast period, the flow was considerably even compared to the on-gas period, and the average blast temperature reached 1345 K. The outer region of the checker chamber is shown to be continuously exposed to a higher temperature, which makes the region the main domain in managing the deterioration of the refractory linings. The shell temperature did not change during the operation due to the lower thermal diffusivity of the refractory linings, where the inner surface of the refractory had a maximum temperature change from 1441 K to 1659 K. The maximum temperature of the shell was 418.4 K at the conical region of the checker chamber side. The conical region had the higher maximum and middle principal thermal stresses due to the presence of a large temperature gradient around the conical region, where the largest maximum and middle principal stresses were 300.6 MPa and 192.0 MPa, respectively. The conical region was found to be a significant area of interest where it had a higher temperature and thermal stress.

Forced, natural and mixed convection of Non-Newtonian fluid flows in a square chamber with moving lid and discrete bottom heating

The aim of the present study is to examine the thermal performance of a power-law fluid for a discretely heated lid-driven enclosure. This numerical outcome can determine the ideal heat transfer medium for a given design, thus reducing unnecessary expenditures on experiments. The chamber's side walls move at a constant speed under constant ambient conditions. The finite element approach is used to solve governing Navier-Stokes and energy equations. A parametric investigation is carried out by varying the Richardson number (Ri) within the range of 2 × 10−3 ≤ Ri ≤ 105 at a fixed Reynolds or Grashof number in different cases and changing them simultaneously while keeping the Richardson number at unity. In all cases, the power-law index (n) is varied within 0.6 ≤ n ≤ 1.4. The results have been presented in terms of a quantitative evaluation of the average Nusselt number of the heated source, the average fluid temperature of the chamber, the maximum temperature of the heat source, and the normalized average Nusselt number. Furthermore, qualitative contour plots of stream function and temperature for different cases are presented. This research shows that the higher the power-law index, the greater the heat transfer for forced and pure mixed convection and that heat transfer performance differs with the increment/decrement of the Richardson number while keeping either Reynolds or Grashof number constant. Besides, the highest heat transfer performance is observed during the natural convection case of the pseudo-plastic fluid, and the lowest heat is transferred when the fluid is dilatant.

Volatile fatty acids and ammonia recovery, simultaneously cathodic hydrogen production and increasing thermophilic dark fermentation of food waste efficiency

A combined thermophilic anaerobic bioreactor of food waste and bioelectrodialysis system was used to recover volatile fatty acids and ammonia as renewable materials and also to remove the inhibitory effect of biohydrogen production byproducts. Different configurations of bioelectrodialysis system under various amounts of inlet food waste and external electrical currents were examined were investigated to find out the best conditions for system performance. When the two anion exchange membranes (AEM) were installed on the anode and cathode sides of separation chamber, 12 mL min-1 of mixed liquid was circulated between fermenter and separation chamber, while the external energy of 2.7 V and 0.2 M NaCl as electrolyte were used in the electrodialysis chambers. As long as the food waste with 70000 mg COD L-1 was used in the fermenter, the concertation of organic acids in the recovery chamber was the highest, 507.3 mg L-1 after 24th h. As a result, 0.63 L L-1 biohydrogen and 50 mL cathodic hydrogen were produced. When a cation exchange membrane was embedded on the cathode side of the separation chamber, the ammonia concertation in the recovery chamber was the highest, 518 mg L-1, at 36th h. At the same time, the chemical oxygen demand of the anode solution was decreased by about 3600 mg L-1. This sustainable and bioelectrical system can recover organic acids and ammonia, cathodic hydrogen production, while simultaneously increase biohydrogen production and efficient even when substrate concentration was higher.

Investigation of Unsteady Pressure Pulsations of Reactor Coolant Pump Passage under Flow Coast-down

In order to obtain the pressure pulsations of a reactor coolant pump during flow coast-down conditions, the time-domain characteristics of the flow passage under different times of flow coast-down were calculated by numerical calculation. Because the unsteady pressure pulsation signals in the RCP under flow coast-down are non-stationary and some phenomena may only occur in a short time, this paper analyzed them with the wavelet transform. The results show that the pressure fluctuation varies dramatically with the flow coast-down process and the variation rate of the pressure fluctuation coefficient can reach more than 60%. With the development of flow coast-down, there is a strong correlation between the pressure pulsation and number of impeller blades. The main frequency of the pressure pulsation gradually changes from high-frequency pulsation to low-frequency pulsation, and the regularity of the pressure pulsation is quickly destroyed, while the change in pressure pulsation regularity of the guide vane passage is more gentle than that of the impeller and pressurized water chamber. The change in wavelet intensity at the impeller outlet, guide vane inlet, and left side of the pressurized water chamber is more intense than at other areas.

Effects of Expansion and Side Chambers on Reduction and Time Delay of Blast Overpressures in Underground Protective Facilities

This study presents numerical investigation of blast overpressures on blast-resistant doors by changing the number of side chambers and the number and shape of expansion chambers for an external detonation. Blast overpressures for four types of door and zero to four chambers were simulated. For the original shape of the underground ammunition magazine with side chamters installed, the peak time delay was approximately 40 ms, showing a clear different, whereas the reduction in the maximum value appeared as small as 3 kPa. Reducing the overpressure and delaying peaks using bottleneck devices and side chambers revealed that, because the size of the tunnel with underground ammunition magazines was partially reduced, the effects of the reduction and time delay of blast overpressures were negligible. When expansion chambers with a size 1.1 times the passage width and side chambers were used, the time delay in the peaks and overpressure reduction were observed. When expansion chambers with a size 1.2 times the passage width and side chambers were used, the delay and reduction effects were significant when two or more chambers were installed, and the effect was almost the same as when the size was 1.1 times the passage width.

Failure analysis of a reducer section in the creep loop of INSOT facility

Sodium leak was observed in the inlet side of a creep testing chamber in an In-Sodium Testing (INSOT) facility for fast breeder reactor structural materials. The failure occurred during a test campaign after 183 h of operation of the loop at a temperature of 823 K. Based on He and liquid penetrant testing, locations of leaks were identified in a reducer section. Detailed metallurgical characterization of the failed reducer and comparison of the results with a reference specimen helped in identifying the sequence of failure based on which recommendations were made to avoid similar failures in the future.

Effect of a Taper Intake Port on the Combustion Characteristics of a Small-Scale Rotary Engine

Taper intake ports are effective in improving the charging efficiency of small-scale rotary engines (REs), but it is unclear how their structural parameters affect the in-cylinder flow field and combustion characteristics. For this reason, the effects of the diameter-length ratio (D/L) of an intake port on the in-cylinder flow field and combustion characteristics of a small-scale RE were numerically investigated by utilizing a three-dimensional computational fluid dynamics (CFD) model. The results showed that the in-cylinder pressure of the RE did not follow a simple single-directional trend with the D/L of the intake port, but it was divided into three levels, where the peak in-cylinder pressure was at its maximum at the D/L of 0.6 and at its minimum at the D/L of 0.8. The gas flows in the intake port with different values of the D/L were all unidirectional, and they made a difference in the vortexes formed on the leading side of the combustion chamber of the RE, which was the main factor affecting the in-cylinder combustion performance. The vortexes formed on the leading side of the combustion chamber with D/L = 0.6 were maintained for a long period of time, thus promoting the propagation of flame and advancing the center of gravity of combustion. So, the heat release rate and combustion efficiency in the cylinder were increased at the price of a larger increment in nitrogen oxide formation.

The excavation of Liao dynasty tomb of Han Derang in Beizhen, Liaoning

Abstract Excavation and survey of the cemetery in the northwest of Hongjiajie, Futun Village, Beizhen City were jointly conducted by the Liaoning Provincial Institute of Cultural Relics and Archaeology and other institutes between 2015 and 2017. Four tombs were excavated. Tomb M4 is square in layout and has a descending entrance corridor leading to the tomb chambers. The tomb consists of an entrance corridor, a ventilation shaft, an entrance, front and rear passages, an antechamber, a main chamber, and two side chambers. Remnants of mural paintings and floor paintings were found in multiple parts of the tomb. Grave goods, including pottery, porcelain, metals, jade, and glass artifacts were retrieved. According to the epitaph, the tomb occupant is Han Derang, the Grand Counselor-in-Chief of the Liao dynasty. This discovery provides significant data for the study of the spatial patterns of Liao imperial mausoleums in Yiwulü Mountain, especially as a reliable reference for confirming the location of the Liao Qianling mausoleum.

The excavation of the 2018 Xuewei tomb No. 1 in Reshui cemetery, Dulan County, Qinghai

Abstract After a looting case was cracked on March 15, 2018, the Institute of Archaeology of the Chinese Academy of Social Sciences and other organizations promptly conducted a rescue excavation of the looted tomb No. 1 at Xuewei. The tomb is the mausoleum of the king of Touyu-houen under Tubo’s rule in the mid-eighth century CE. It consists of two parts: the tomb compound aboveground and the underground structure. The former includes enclosure walls, sacrificial buildings, a mound, and a cloister. The latter consists of the entry ramp, the tomb pit, the screen wall, the tomb corridor, and the tomb chambers comprised of a main chamber and four side chambers, which is consistent with the document that recorded an “Inner-Mound Shrine of Five Gods.” The main chamber includes mural paintings, red-colored representations of wooden bracket sets, painted double coffins, a coffin platform, and an offering altar. A large number of artifacts predominated by goldware and textiles were uncovered. Amongst them, a silver seal bearing the inscription “seal of the King of Achai, the nephew” provides critical evidence for the confirmation of the status and ethnic identity of the tomb occupant.

Extreme diagenesis in the Late Pleistocene stratigraphic sequence of Grotta Guattari (central Italy) and its impact on the archaeological record

Grotta Guattari is a key cave site for Mediterranean prehistory. It is where a perfectly preserved paleo-surface, littered with bones and containing a Neandertal cranium, was exposed in 1939. Recent research, moreover, has yielded even more Neandertal remains in a side chamber that had remained unexplored. This paper gives an account of the stratigraphic sequence of the atrial portion of Grotta Guattari described in 1989 along the walls of the 1939 to 1950 excavation trenches. This key sequence, capable of elucidating the sequence of events recorded in Grotta Guattari, remained until now unstudied. The stratigraphy represents the interval between ca 125 ky BP (Marine Isotope Stage – hereafter, MIS – 5.5 or Tyrrhenian transgressive cycle) and ca 50 ky BP (MIS 3). Grain size, chemical, and heavy mineral analyses were coupled with the micromorphological study of thin sections, corroborated by SEM/EDS chemical determinations and XRD analyses. The presence of secondary Ca–Al and Ca–Fe phosphates, formed in response to the weathering of guano, indicates that part of the archaeological record (bones and ash) has weathered away. Weathering was so intense that also the more unstable mineral species, especially augite, disappeared from the heavy mineral assemblage. The differential preservation of the archaeological record shall therefore be taken in consideration when interpreting in behavioural terms old and new excavation data.

2D MHD Mixed Convection in a Zigzag Trapezoidal Thermal Energy Storage System Using NEPCM.

In a magnetic field, two-dimensional (2D) mixed convection is investigated within a zigzagged trapezoidal chamber. The lower side of the trapezoidal chamber is irregular, in particular, a zigzagged wall with different zigzag numbers N. The fluid particles move in the room due to the motion of the upper wall, while the porosity-enthalpy approach represents the melting process. The thermal parameters of the fluid are enhanced by what is called a nano-encapsulated phase change material (NEPCM) consisting of polyurethane as the shell and a nonadecane as the core, while water is used as the base fluid. In order to treat the governing equations, the well-known Galerkin finite element method (GFEM) is applied. In addition, the heat transfer (HT) irreversibility and the fluid friction (FF) irreversibility are compared in terms of the average Bejan number. The main results show that the melt band curve behaves parabolically at smaller values of Reynolds number (Re) and larger values of Hartmann number (Ha). Moreover, minimizing the wave number is better in order to obtain a higher heat transfer rate.

Solving the challenging puzzle of the Grimsel II runner vibration

After 30 years of operation, the runners of the four 100 MW high-head Francis turbines successively developed fatigue cracks starting from the hub-side trailing-edge fillets. Assessment of alternating stress in normal turbine operation revealed that stress levels were not nearly large enough to explain the damages. Consequently, a test campaign comprising start and stop manoeuvres in addition to normal turbine operation was conducted in 2017. Strain gauge signals obtained on-board of the runner blades were recorded together with casing vibration and acoustic signals. Intense high-frequency vibration centred around 611 Hz was detected in three transient conditions of operation: at speed-no-load (SNL), during coast-down and during back-to-back pump start. Common properties of these conditions were very low to no discharge, strong secondary flow in the runner and speed between 50 and 100 %. Due to the extremely narrow bandwidth, three possible ways of excitation were considered and checked: rotor-stator interaction (RSI), rotor-dynamic instability and Von Kármán excitation. RSI was excluded due to speed-independent frequency. Strong sidebands in the stationary-frame frequency spectra - obviously caused by runner shroud deformation shapes ND1 through ND5 - excluded any feedback from runner side chamber pressure; thus leaving Von Kármán excitation as the only possible diagnosis. Accordingly, a very safe profile was selected and implemented for the runner blade trailing edges. Subsequent field-testing at two modified units confirmed that the vibration problem at the harmful operation points had hereby been eliminated.

Experimental arrangement for estimation of metal-mold boundary heat flux during gravity chill casting

The cooling rate of the castings is determined by the rate of heat transfer into the mould during solidification, which has a considerable impact on their characteristics. The thermo-physical properties of the casting and mould materials determine the heat flow rate/cooling rate. Heat flow on the inner and external surfaces of the mould can be calculated using the Inverse Heat Conduction Problem, often known as the Inverse Approach (IHCP). On one side of the rectangular mould chamber, cold materials such as cast iron, stainless steel, and copper are used. For the experimentation, a simple gravity die casting in a rectangle mould is explored. At various points throughout the mould, mineral insulated K-type thermocouples are put. The thermocouples are wired into a data collecting system that connects to a computer. During pouring and subsequent solidification, the mold's time–temperature history is recorded. These recorded transient temperatures are supplied into the inverse method as input (IHCP). The surface heat flux is calculated as a function of time by the solver.

Раннесарматские погребения могильника Верхний Балыклей I из Заволжья

The paper introduces into scientific discourse the materials of the early Sarmatian burials from the Verkhniy Balykley I kurgan cemetery from the area of the Volgograd Trans-Volga region. This monument was studied in the course of the 1978–1979 expedition organized by the Volgograd State Pedagogical Institute under the leadership of A.S. Skripkin. Materials. The burial includes four mounds located compactly on the banks of the reservoir and one single mound setting far away in the steppe. Eighteen inlet burials of the early Sarmatian time were found in three Bronze Age kurgans. Some burials contained no burial inventory; others did include a variety of grave goods. The funeral rites present a wide range of grave structures: pits with side chambers, simple rectangular pits and catacombs. The southern body orientation of the buried individuals was dominating. In kurgans 5 and 6, a circular arrangement of graves is traced, which is typical for early Sarmatian mounds-cemeteries. Material analysis. An analysis of the grave goods indicates 3rd – 1st centuries BC is the time of construction of most burials in these kurgans, which does not contradict the funeral rite traditions and reveals a range of features characteristic of the nomads of that period. A military burial with a long sword and arrows is one of the most distinguished in its kind. Ceramic material is represented by various stucco forms of pots, an incense burner and a jug. Fragments of mirrors with rollers along the edge and beads were discovered in several burials. Several stone “miniature hammers”, typical for the South Ural grave materials of this period, is also an interesting find. Conclusions. In general, the studied monuments illustrate the burial traditions of the early Sarmatian population of the Ural-Volga steppes of the early Sarmatian time. The finds of pottery samples, previously unknown stone “miniature hammers” in the west of the Volga, allow us to conclude on the cultural proximity of the nomads who left the mounds near the village Verhniy Balykley with the South Ural nomads. Authors’ contribution. In this paper, Anatoly S. Skripkin prepared a descriptive part of the archaeological material; Vladimir I. Moiseev analyzed the funeral rite and the inventory. Mikhail V. Krivosheev drew and presented conclusions on the analysis of the material.

Simple Electric Device to Isolate Nucleic Acids from Whole Blood Optimized for Point of Care Testing of Brain Damage.

Detection or monitoring of brain damage is a clinically crucial issue. Nucleic acids in the whole blood can be used as biomarkers for brain injury. Polymerase chain reaction (PCR) which is one of the most commonly used molecular diagnostic assays requires isolated nucleic acids to initiate amplification. Currently used nucleic acid isolation procedures are complicated and require laboratory equipments. In this study, we tried to develop a simple and convenient method to isolate nucleic acids from the whole blood sample using a tiny battery-powered electric device. The quality of the isolated nucleic acids should be suitable for PCR assay without extra preparation. A plastic device with separation chamber was designed and printed with a 3D printer. Two platinum electrodes were placed on both sides and a battery was used to supply the electricity. To choose the optimal nucleic acid isolation condition, diverse lysis buffers and separation buffers were evaluated, and the duration and voltage of the electricity were tested. Western blot analysis and PCR assay were used to determine the quality of the separated nucleic acids. 2ul of whole blood was applied to the cathode side of the separation chamber containing 78 ul of normal saline. When the electricity at 5 V was applied for 5 min, nucleic acids were separated from segment 1 to 3 of the separation chamber. The concentration of nucleic acids peaked around 7~8 mm from cathode side. PCR assay using the separation buffer as the template was performed successfully both in conventional and realtime PCR methods. The hemoglobin in the whole blood did not show the inhibitory effect in our separation system and it may be due to structural modification of hemoglobin during electric separation. Our simple electric device can separate nucleic acids from the whole blood sample by applying electricity at 5 V for 5 min. The separation buffer solution taken from the device can be used for PCR assay successfully.

Endocardial Regulation of Cardiac Development

The endocardium is a specialized form of endothelium that lines the inner side of the heart chambers and plays a crucial role in cardiac development. While comparatively less studied than other cardiac cell types, much progress has been made in understanding the regulation of and by the endocardium over the past two decades. In this review, we will summarize what is currently known regarding endocardial origin and development, the relationship between endocardium and other cardiac cell types, and the various lineages that endocardial cells derive from and contribute to. These processes are driven by key molecular mechanisms such as Notch and BMP signaling. These pathways in particular have been well studied, but other signaling pathways and mechanical cues also play important roles. Finally, we will touch on the contribution of stem cell modeling in combination with single cell sequencing and its potential translational impact for congenital heart defects such as bicuspid aortic valves and hypoplastic left heart syndrome. The detailed understanding of cellular and molecular processes in the endocardium will be vital to further develop representative stem cell-derived models for disease modeling and regenerative medicine in the future.