Extraction Grid Research Articles

Negative ion beam extraction experiments on the KAERI negative ion source

A small-scale test stand of a negative NBI source composed of a prototype negative ion source, an RF generator, and an HV power supply for negative ion beam extraction has been established. The magnetic filter and a beam extraction grid system with electron deflection magnets were designed for the prototype negative ion source. The BL value of the magnetic filter is 1.6mTm and almost all electrons are deflected onto the surface of the extraction grid. The first negative ion beam extraction experiments have been carried out. When the extraction voltage is 5.6kV, the negative ion current density is 0.6mA/cm2at 5kW RF power. The e/H− ratio is about 2–3 and it decreased below 1 when the electrical potential of the plasma bucket is grounded.

Pore pressure prediction of some selected wells from the Southern Pletmos Basin, offshore South Africa

An accurate pore pressure prediction is vital in any risk management plan during the exploration, exploitation and development of wells in the petroleum industry. It is therefore important to understand the factors controlling these pore pressures namely, sediment compaction, overburden, lithology characteristics, hydrocarbon generation, tectonic stress, thermodynamic effects, osmosis and clay mineral transformation, which are all influenced by physical, geological, geochemical and mechanical processes. In this study we present the results of data selected from three wells: Ga-N1, Ga-W1 and Ga-AA1, which were all drilled within the Southern Pletmos sub-basin, offshore South Africa. The pore pressure in the wells was predicted using the Ben Eaton method by creating a depth dependent Normal Compaction Trend (NCT), using resistivity and sonic wireline logs. 2D seismic data were used to develop depth imaging of the pre-drilling pore pressure predictions; this was done using seismic interval velocity data and pressure data to obtain a reflection tomography extraction grid map. Detailed depth plots of overburden gradient (OBG), the Effective Stress (ES), Fracture Gradient (FG), Fracture Pressure (FP), Pore Pressure Gradient (PPG), and the Predicted Pore Pressure (PPP) were thus derived for the three wells. The overburden density varies from 2.09 gm/cc to 2.24 gm/cc between the wells, while the PPP changes from 3,405 psi to 5,062 psi within the selected reservoir intervals. The results show that most of the reservoir intervals of the three wells experience normal pore pressures (between 3000 and 4000 psi), except the reservoir intervals between depths 1868.73 m to 1875.40 m and 1880.3 m to 1887.3 m, respectively, in well Ga-W1, where significant overpressure in the pores exceeding 4000 psi was demonstrated (normal pore pressures are between 3000 and 4000 psi). The tomography extraction grid map that was generated from 2D seismic data of the wells was used to delineate the depth imaging of the pore pressure, in both overpressure and normal pressure formations before drilling, yielded good results.

Cylindric high power impulse magnetron sputtering source and its discharge characteristics

High power impulse magnetron sputtering (HiPIMS) is a popular physical vapor deposition (PVD) technology because of the high ionization of the sputtering materials, large coating density, good adhesion, and other favorable properties. However, this technique suffers some disadvantages such as the small deposition rate induced by the high target potential, the metallic droplets produced by the unstable discharge, and different ionizations for different sputtering materials, thereby hampering wider acceptance by the industry. A cylindric HiPIMS source in which the discharge is restricted in the cylinder is described in this paper. By using this source, coatings can be deposited with 100% ions without metallic droplets arising from the unstable discharge, and the unionized sputtered atoms cannot be extracted by the extraction grid with negative potential. Electron oscillation and repetitive sputtering of the unionized atoms occur in the cylinder to enhance collision and ionization. Due to the enlarged discharge area by the cylinder internal surface comparing with the area of the ion outlet (end face of the cylinder), the sputtering ions converge from the inwall to the center of the cylinder target and form an enhanced flow to spray out from the source, which will improve the deposition rate. The structure and discharge characteristics of the novel HiPIMS source are investigated by simulation and experiments. Our results indicate that 8 magnets can provide the reasonable magnetic field and the highest target utilization rate. The distributions of electrons and ions in the target each consist of 8 petals in the optimized magnetic structure, and the highest plasma density happens near the target, which is above 1.31017 m-3. The discharge characteristics confirm that the cylindric sputtering source can be operated under HiPIMS conditions and the evolution of the target currents with target voltage exhibits I-V characteristics typical of HiPIMS. An obvious pre-ionization is observed on the discharge glow and discharge current curves when the extra direct current (DC) is added. The racetrack area is about 60.0% of the target surface. The ion current curves are similar to those of the target currents, but a 40 s delay and about one-tenth current value are observed compared with the target currents. The sputtering is improved by the extra DC, inducing the increased metallic ions and the opposite evolution of gas ions. The results suggest that the cylindric sputtering source can be effectively used to conduct HiPIMS and is a novel way to improve and promote the application of HiPIMS.

The characterization and optimization of NIO1 ion source extraction aperture using a 3D particle-in-cell code.

The geometry of a single aperture in the extraction grid plays a relevant role for the optimization of negative ion transport and extraction probability in a hybrid negative ion source. For this reason, a three-dimensional particle-in-cell/Monte Carlo collision model of the extraction region around the single aperture including part of the source and part of the acceleration (up to the extraction grid (EG) middle) regions has been developed for the new aperture design prepared for negative ion optimization 1 source. Results have shown that the dimension of the flat and chamfered parts and the slope of the latter in front of the source region maximize the product of production rate and extraction probability (allowing the best EG field penetration) of surface-produced negative ions. The negative ion density in the plane yz has been reported.

Barriers and facilitators to implementing continuous quality improvement programs in colonoscopy services: a mixed methods systematic review.

Background and aim: Continuous quality improvement (CQI) programs may result in quality of care and outcome improvement. However, the implementation of such programs has proven to be very challenging. This mixed methods systematic review identifies barriers and facilitators pertaining to the implementation of CQI programs in colonoscopy services and how they relate to endoscopists, nurses, managers, and patients. Methods: We developed a search strategy adapted to 15 databases. Studies had to report on the implementation of a CQI intervention and identified barriers or facilitators relating to any of the four groups of actors directly concerned by the provision of colonoscopies. The quality of the selected studies was assessed and findings were extracted, categorized, and synthesized using a generic extraction grid customized through an iterative process. Results: We extracted 99 findings from the 15 selected publications. Although involving all actors is the most cited factor, the literature mainly focuses on the facilitators and barriers associated with the endoscopists’ perspective. The most reported facilitators to CQI implementation are perception of feasibility, adoption of a formative approach, training and education, confidentiality, and assessing a limited number of quality indicators. Receptive attitudes, a sense of ownership and perceptions of positive impacts also facilitate the implementation. Finally, an organizational environment conducive to quality improvement has to be inclusive of all user groups, explicitly supportive, and provide appropriate resources. Conclusion: Our findings corroborate the current models of adoption of innovations. However, a significant knowledge gap remains with respect to barriers and facilitators pertaining to nurses, patients, and managers.

Implementation and verification of a hybrid performance and impedance model of gridded radio-frequency ion thrusters

In this paper, we show the development steps for an iterative performance and impedance model of gridded radio-frequency (RF) ion thrusters. The input parameters are equivalent to those of the real propulsion system; i.e., coil current, propellant mass flow, and extraction grid voltages. Therefore, the model is easily validated and verified by experimental data and can furthermore be used to optimize the overall thruster performance. The model predicts volume-averaged plasma parameters such as electron temperature, conductivity, total pressure, and ionization fraction as well as thruster performance data like generated thrust, specific impulse, and mass and electrical efficiency. The above mentioned plasma parameters are obtained as functions of the discharge chamber’s geometry by using a charge balance equation that relates generated ions to ions lost at the chamber’s walls. The plasma related quantities influence the electromagnetic field penetration which is here evaluated by means of a diffusion equation for the vector potential. The vector potential is obtained by a 3D Finite-Difference-Method on a cubic and rectangular grid which, in principle, offers the opportunity to have arbitrary plasma chamber and coil geometries. An actual ion thruster geometry is evaluated in this study in favor of experimental verification of the numerically obtained data. The thruster’s coil generates highly asymmetric electromagnetic fields which motivates the use of a three-dimensional solver. A dissipation model based on Ohm’s law and Poynting’s theorem is used to determine the absorbed power within the discharge. To obtain a stable solution, the electromagnetically absorbed power is equated to the power lost due to elastic and inelastic collisions and electron wall flux. This whole process is iteratively repeated until the degree of ionization converges within a given threshold. To relate the stable discharge parameters to the thruster performance an extraction model based on a modified version of Child-Langmuir’s law is used. Within the model, the extracted ion beam current is calculated as a function of extraction aperture, applied extraction voltage, and plasma sheath size. A particle balance equation is then used to iteratively compute the total pressure combining neutral, electron, and ion pressures. After convergence, the plasma impedance, typically described by a transformer model, is transformed to its equivalent series representation as seen by the RF source at its terminals. Furthermore, thruster performance data are evaluated which gives rise to use this model for optimization purposes. It can thus be regarded as a toolbox for virtual prototyping.

Molecular ion sources for low energy semiconductor ion implantation (invited).

Smaller semiconductors require shallow, low energy ion implantation, resulting space charge effects, which reduced beam currents and production rates. To increase production rates, molecular ions are used. Boron and phosphorous (or arsenic) implantation is needed for P-type and N-type semiconductors, respectively. Carborane, which is the most stable molecular boron ion leaves unacceptable carbon residue on extraction grids. A self-cleaning carborane acid compound (C4H12B10O4) was synthesized and utilized in the ITEP Bernas ion source resulting in large carborane ion output, without carbon residue. Pure gaseous processes are desired to enable rapid switch among ion species. Molecular phosphorous was generated by introducing phosphine in dissociators via 4PH3 = P4 + 6H2; generated molecular phosphorous in a pure gaseous process was then injected into the HCEI Calutron-Bernas ion source, from which P4(+) ion beams were extracted. Results from devices and some additional concepts are described.

Implementation of the Integrated Electronic Patient Portal in the Pediatric Population: A Systematic Review.

This study assessed the current state of knowledge regarding the use of the integrated electronic health record (EHR) patient portal for pediatric clinical care. A systematic examination of the research on implementation, utilization, and evaluation of the integrated EHR patient portal among pediatric patients has not been previously conducted. Therefore, the purpose of the present study was to systematically review existing research on the state of the science, describe the way others have defined the patient portal, and examine pediatric patient portal utilization. Covering a period from 1992 to 2014 a literature search was conducted on four electronic databases. Only articles in English were reviewed. Studies were included if they reported the use of a patient portal integrated with an electronic health record and captured pediatric medial encounters. Qualitative or quantitative studies of any design were eligible as long as they focused on patients (or parents) who access their health records through an electronic portal tied to an EHR and reported measures of satisfaction, attitudes on use, barriers and facilitators, adherence, or clinical and health outcomes. Content analysis of each article was performed independently by at least two authors using an extraction grid of study qualities, and quality and relevance of the studies were also assessed. Of a total of 189 potentially relevant publications identified, 31 full-text publications were obtained after screening titles and abstracts. After a full review, 11 publications corresponding to seven studies met the inclusion criteria. The methodological approaches included cross-sectional surveys, retrospective analysis, qualitative studies, and usability testing. In general, feedback was positive. The most frequent negative comments about the portal reflected concern about teenager interaction with the portal and how that might affect communication among patient, parent, and provider. Some users were frustrated with the complexity of medical terminology used. Reflecting the additional considerations of pediatric proxy access and fewer chronically ill patients, pediatric medicine has yet to use the patient portal as a modality for outcomes measurement. Given the paucity of studies within this age group, it is difficult to measure outcome improvements or the effect of patient record access on healthcare behaviors. This systematic review presents innovative research on the general acceptance of the patient portal among parents and highlights that the implementation of the portal is still in its early stages and has yet to be used widely in diverse populations or studies in a longitudinal manner. Further studies should confirm that protected access to health information and secure communication and information sharing with healthcare providers have an impact in the pediatric population on healthcare outcomes.

M-Health adoption by healthcare professionals: a systematic review.

The aim of this systematic review was to synthesize current knowledge of the factors influencing healthcare professional adoption of mobile health (m-health) applications. Covering a period from 2000 to 2014, we conducted a systematic literature search on four electronic databases (PubMed, EMBASE, CINAHL, PsychInfo). We also consulted references from included studies. We included studies if they reported the perceptions of healthcare professionals regarding barriers and facilitators to m-health utilization, if they were published in English, Spanish, or French and if they presented an empirical study design (qualitative, quantitative, or mixed methods). Two authors independently assessed study quality and performed content analysis using a validated extraction grid with pre-established categorization of barriers and facilitators. The search strategy led to a total of 4223 potentially relevant papers, of which 33 met the inclusion criteria. Main perceived adoption factors to m-health at the individual, organizational, and contextual levels were the following: perceived usefulness and ease of use, design and technical concerns, cost, time, privacy and security issues, familiarity with the technology, risk-benefit assessment, and interaction with others (colleagues, patients, and management). This systematic review provides a set of key elements making it possible to understand the challenges and opportunities for m-health utilization by healthcare providers.

Progress in long-pulse production of powerful negative ion beams for JT-60SA and ITER

Significant progress in the extension of pulse durations of powerful negative ion beams has been made to realize the neutral beam injectors for JT-60SA and ITER. In order to overcome common issues of the long-pulse production/acceleration of negative ion beams in JT-60SA and ITER, new technologies have been developed in the JT-60SA ion source and the MeV accelerator in Japan Atomic Energy Agency.As for the long-pulse production of high-current negative ions for the JT-60SA ion source, the pulse durations have been successfully increased from 30 s at 13 A on JT-60U to 100 s at 15 A by modifying the JT-60SA ion source, which satisfies the required pulse duration of 100 s and 70% of the rated beam current for JT-60SA. This progress was based on the R&D efforts for the temperature control of the plasma grid and uniform negative ion productions with the modified tent-shaped filter field configuration. Moreover, each parameter of the required beam energy, current and pulse has been achieved individually by these R&D efforts. The developed techniques are useful to design the ITER ion source because the sustainment of the caesium coverage in the large extraction area is one of the common issues between JT-60SA and ITER.As for the long-pulse acceleration of high power density beams in the MeV accelerator for ITER, the pulse duration of MeV-class negative ion beams has been extended by more than 2 orders of magnitude by modifying the extraction grid with a high cooling capability and a high transmission of negative ions. A long-pulse acceleration of 60 s has been achieved at 70 MW m−2 (683 keV, 100 A m−2) which has reached the power density of JT-60SA level of 65 MW m−2. No degradations of the voltage holding capability of the acceleration voltage and the beam optics due to the distortion of the acceleration grids have been observed in this power density level.These results are the longest pulse durations of high-current and high-power-density negative ion beams in the world.

Recent progress in R&D for long pulse and ultra-high voltage components for the ITER HNB

Toward ITER, the long-pulse acceleration of MeV-class negative ion beams has been successfully demonstrated and R&Ds and the procurement of high-voltage components of 1MV power supply system have been progressed. In the accelerator development after the production of 1MeV beams, an extraction grid, where a water cooling is reinforced and the beam is steered by aperture offset to suppress grid heat loads, has been newly developed to extend the pulse duration of the MeV-class beams. As the result, a total grid heat load has been reduced from 20% to 10% of the total beam power. The beam pulse was successfully increased from 0.4s to 60s at 0.68MeV, 100A/m2 and 12s at 0.89MeV, 156A/m2 beams. As for the procurement of the 1MV power supply system, 1MV insulating transformer as the critical component has been developed. In the mock-up, a dc 1.2MV for 1h with the margin of 20% was stably sustained. Through the R&Ds of the critical components, design of five power supplies procured by JAEA has been finalized, and out of which a testing power supply has been completed in June 2014.

Beam current in extraction system of neutral beam ion source on HL-2A

In the extraction process of neutral beam ion source, the production of extraction current and deceleration current is analyzed and it is helpful for obtaining reliable extraction power and heat deposition power on the grids surface. Based on the electric connection way of the extraction grids of neutral beam ion source on HL-2A and the basic physical process during ion beam extraction, beam extraction process is analyzed and the principle sources of deceleration current are given. Through analyzing the results in gas pressure scanning experiment, it is found that with gas pressure increasing, deceleration current increases, and the ratio of deceleration current to extraction current increases approximately linearly. A physical model is set up based on the process of extracted ion beam coming through the extraction grids. The dependence of the ratio of deceleration current to the acceleration current on the discharge gas pressure is calculated, and the result is consistent with the experimental result which shows the rationality of the analysis method.

On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

The development of a large area (Asource,ITER = 0.9 × 2 m2) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (Asource,BATMAN ≈ 0.32 × 0.59 m2) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child–Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion–ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions and electrons, agree rather well with the experiment.

Manufacturing and Testing of Grid Prototypes for the ITER Neutral Beam Injectors

A comprehensive set of research and development activities has been carried out at Consorzio RFX regarding the construction of the grids for the ITER neutral beam injectors, in order to validate the proposed manufacturing methodologies, to further develop the details of the engineering design, and to adapt existing production techniques to the specific case. In the framework of this research and development program, two multichannel prototypes have been designed and manufactured. These prototypes feature all the possible manufacturing issues of the source for production of ion of deuterium extracted from RF plasma (SPIDER) grids. In fact, they reproduce the geometry of the extraction grid (EG) for SPIDER by having the same thickness, same cooling channels, same distributors, same aperture shape, and same slots for the magnets of an EG segment. The differences from an actual EG segment regard only the dimensions, i.e., reduced width (one fourth) and height (one half). The construction and testing of these prototypes are here described in detail.

Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application

High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions.

On the electron extraction in a large RF-driven negative hydrogen ion source for the ITER NBI system

The test facility ELISE, equipped with a large RF-driven ion source (1 × 0.9 m2) of half the size of the ion source for the ITER neutral beam injection (NBI) system, has been constructed over the last three years at the Max-Planck-Institut für Plasmaphysik (IPP), Garching, and is now operational. The first measurements of the dependence of the co-extracted electron currents on various operational parameters have been performed. ELISE has the unique feature that the electron currents can be measured individually on both extraction grid segments, leading to vertical spatial resolution. Although performed in volume operation, where the negative hydrogen ions are created in the plasma volume solely, the results are very encouraging for operation with caesium, this being necessary in order to achieve the relevant negative ion currents for the ITER NBI injectors. The amount of co-extracted electrons could be suppressed sufficiently with moderate magnetic filter fields and by plasma grid bias. Furthermore, the electron extraction is more or less decoupled from the main plasma, as the observed vertical asymmetry of electron extraction is not correlated at all with the plasma asymmetry, which is anyway rather small. Both effects are superior to the experience from the small IPP prototype source; the reason for these encouraging results is most probably the larger size of the source as well as the new geometry of the source having unbiased areas in its centre. The reasons, however, for the observed asymmetry of the extracted electron currents and their dependencies on various operational parameters are not well understood.

Non-ideal operating conditions of the ion source prototype for the ITER neutral beam injector due to thermal deformation of the support structure

The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.

Three-dimensional structure of the extraction region of a hybrid negative ion source

A self-consistent three-dimensional particle-based model of the source extraction–acceleration transition region of a surface-produced negative ion source is developed. Some considerations are advanced on the characteristic of negative ion transport: it is purely electrostatic while collision-induced (charge exchange with atoms) and magnetic-induced (ion gyration around the filter field) transport contributions play no relevant role in H− extraction. In fact, the calculations presented here indicate that the key point is the penetration of the extraction grid field inside the plasma grid collar and the source region, which helps in removing the negative ions produced on the surface. This study suggests that the best plasma grid shape is characterized so as to allow the extraction field to arrive directly on the surface-emitting H− ions and that the best aperture size is directly related to the particular shape used.

The Interaction of Public Health and Primary Care: Functional Roles and Organizational Models that Bridge Individual and Population Perspectives

Introduction: Public health and primary care are often conceived as two entities providing complementary services within the health system. This scoping review aims to better understand how the two sectors interact by identifying their shared functions, and by identifying organizational models that could facilitate the interaction between the two domains. Methodology: We conducted a review of published literature using PubMed and CINAHL journal indices. Our search yielded 179 articles. We reviewed abstracts and retained 55 relevant articles. We developed an extraction grid, based on a conceptual framework of functions of public health and primary care, in order to evaluate the relevance of selected articles, classify the information according to their functional connection, and identify interactions between them. Results: Our search identified various activities through which public health can contribute to more effective primary care, and functions usually performed by primary care that seemed to support a population health approach. Most authors identified screening and immunization as actions that are carried out in primary care, but that can benefit from the support of public health. Health promotion and lifestyle modification are also shared responsibilities that can take the form of collective or individual intervention. The surveillance and protection function of public health, which actually takes place in primary care, consists of case identification for prevention or early treatment. Primary care is the setting where patients present, whereas public health has the role of investigation and of providing advice to clinical settings. Planning and evaluation are also emerging activities that concern both public health and primary care. Many authors recognized that public health provides tools that enhance the planning of primary care activities and are more aligned with the actual needs of populations. Others noted that public health is able to assess primary care in light of the changing health of populations, which may lead to better results for groups of patients. Conclusion: One of the routes to a better understanding of how public health and primary care organizations can better interact is to identify the different contexts in which they collaborate successfully. Our scoping review of the scientific and gray literature identified various ways by which public health and primary care either reinforce each other through their respective functions, or increasingly act in a collaborative manner to increase population health and improve health systems performance.

Performance of the OTSC System in the endoscopic closure of iatrogenic gastrointestinal perforations: a systematic review

Reliable closure is a prerequisite for conventional and innovative endoscopic procedures, such as NOTES. The purpose of this study is the systematic evaluation of the procedural and clinical success rates in closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the over-the-scope-clip system (OTSC(®)). PubMed and other sources were searched systematically for clinical and preclinical research on the evaluation of the OTSC System for closure of gastrointestinal perforations and leaks. Appraisal of studies for inclusion and data extraction was performed independently by two reviewers using an a priori determined data extraction grid. Major endpoints to be extracted were data on procedural success (successful clip application) and clinical access (durable closure of defect without secondary adjunct therapy). A total of 17 clinical research articles/abstracts and 22 preclinical research articles/abstracts were identified. The examined clinical studies comprised case series and clinical single-arm studies. The reviewed studies revealed a consistently high mean rate of procedural success of 80-100 % and durable clinical success of 57-100 %. An identified major drawback preventing successful clip application was occurrence of fibrotic or inflamed lesion edges. Usage of the OTSC System was accompanied by neither major clip-related nor application-related complication. In experimental settings, closure of larger perforations and gastric access sites of NOTES or endoscopic full-thickness resection were achieved with high rates of success. Because randomized, clinical trials are not available in this field of indication, the evaluation is based on small case series. Nevertheless, by pooling all experience gained, we conclude that endoscopic closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the OTSC System is a safe and effective method.