Significant Amount Of Debris Research Articles

Retrograde approach for innominate artery stenting using flow reversal for neuroprotection in Re-operative carotid field

A case of a 74 year old female with a prior history of right carotid endarterectomy (CEA) followed by carotid interposition bypass with polytetrafluoroethylene (PTFE) graft several years later due to restenosis. At 1 year follow up, she was found to have low velocities in the bypass and reversal of flow in her right vertebral artery indicating proximal stenosis. A computed tomography angiography (CTA) and magnetic resonance angiography (MRA) were obtained showing high grade occlusive lesion at her innominate artery. After an unsuccessful attempt at transfemoral endovascular intervention, the patient was brought back for a transcarotid retrograde approach utilizing ENROUTE ® Neuroprotection System with flow reversal for embolic protection. The lesions was crossed successfully in this approach and a balloon mounted covered stent was deployed using Gore ® VBX stent. There was significant amount of debris in the filter which would have embolized without neuroprotection. Patient was discharged on postoperative day 1 with no neurological deficits. In conclusion, this case highlights a successful use of ENROUTE ® Neuroprotection System flow reversal for retrograde transcarotid approach to treat difficult innominate lesions with satisfactory embolic protection.

CFD based wall condensation model for evaluating PCV conditions in Fukushima Daiichi Unit-1

Even after seven years since the Fukushima accident, conditions inside Fukushima Daiichi Unit-1 (1F1) remain mostly unknown, making decommissioning activities challenging. Furthermore, practical data from within the primary containment vessel (PCV) of 1F1, which may provide crucial information for decommissioning activities, have not been assessed sufficiently. In this study, an alternative approach for evaluating such practical data is investigated. In this approach, the condition of debris inside the PCV is estimated through computational fluid dynamics (CFD) simulations performed using STAR-CCM+. Heat transfer inside the PCV is modeled with the developed wall condensation. The wall condensation model is firstly validated through experiment results from COPAIN tests and applied to the PCV of 1F1. Possible locations of debris and decay power that dissipated and heated the environment inside the PCV are then estimated using the simulation results. Moreover, temperature asymmetry observed from practical data on safety valves is also addressed by conducting parameter analysis for different decay powers. The results suggest that 5% of decay heat (65 kW) dissipated to heat gas inside the PCV, and temperature asymmetry on safety valves could be explained by 2% of decay heat (20 kW) as the heat source. A significant amount of debris is estimated to exist inside the pedestal and safety relief valve locations, and some may have spread to the drywell floor through the doorway opening of the pedestal. The findings of the study contribute towards improved decommissioning of 1F1.

Evaluation of Apical Extrusion of Debris, Irrigant Solution and Bacteria after Canal Instrumentation using iRace, Wave One and ProTaper NEXT: An In Vitro Study

Aim: Extrusion of debris during endodontic preparation carries the risk of flare-ups. Purpose of this study was to evaluate and compare the three different rotary systems (ProTaper Next, WaveOne and iRace) for the amount of debris, irrigant, and bacteria they extruded apically. Materials and methods: Present study is an in vitro, experimental single-blinded randomized study. Thirty extracted premolars were used for the study. Biomechanical preparations of the specimens were done using either ProTaper Next, WaveOne or iRace file systems. The apically extruded irrigant was collected and measured using the Myers and Montgomery model. Statistical analysis was done using Mann–Whitney and Kruskal–Wallis test. The level of significance was set at <0.05. Results: Study revealed that WaveOne extruded least bacteria and debris and Protaper Next the highest which was statistically significant. WaveOne group and Protaper Next had more number of irrigant extrusion than iRace. The difference between WaveOne and iRace was statistically significant. A significant difference was noted in the amount of debris, bacteria, and irrigant between WaveOne and iRace. A significant difference was also noted in the amount of debris, irrigant, and bacteria extruded between Protaper Next and iRace. Conclusion: Significant amount of debris and bacterial extrusion was seen in ProTaper Next followed by iRace and WaveOne, whereas apical extrusion of irrigant solution, was greater with WaveOne than ProTaper Next and iRace. Clinical significance: WaveOne causes the least extrusion of debris and bacteria and this outcome would help in the selection of the system while choosing the rotary system for endodontic treatment.

Final payload test results for the RemoveDebris active debris removal mission

Since the beginning of the space era, a significant amount of debris has progressively been generated in space. Active Debris Removal (ADR) missions have been suggested as a way of limiting and controlling future growth in orbital space debris by actively deploying vehicles to remove debris. The European Commission FP7-sponsored RemoveDebris mission, which started in 2013, draws on the expertise of some of Europe's most prominent space institutions in order to demonstrate key ADR technologies in a cost effective ambitious manner: net capture, harpoon capture, vision-based navigation, dragsail de-orbiting.This paper provides an overview of some of the final payload test results before launch. A comprehensive test campaign is underway on both payloads and platform. The tests aim to demonstrate both functional success of the experiments and that the experiments can survive the space environment. Space environmental tests (EVT) include vibration, thermal, vacuum or thermal-vacuum (TVAC) and in some cases EMC and shock. The test flow differs for each payload and depends on the heritage of the constituent payload parts. The paper will also provide an update to the launch, expected in 2017 from the International Space Station (ISS), and test philosophy that has been influenced from the launch and prerequisite NASA safety review for the mission.The RemoveDebris mission aims to be one of the world's first in-orbit demonstrations of key technologies for active debris removal and is a vital prerequisite to achieving the ultimate goal of a cleaner Earth orbital environment.

RemoveDEBRIS: An in-orbit active debris removal demonstration mission

Since the beginning of the space era, a significant amount of debris has progressively been generated. Most of the objects launched into space are still orbiting the Earth and today these objects represent a threat as the presence of space debris incurs risk of collision and damage to operational satellites. A credible solution has emerged over the recent years: actively removing debris objects by capturing them and disposing of them.This paper provides an update to the mission baseline and concept of operations of the EC FP7 RemoveDEBRIS mission drawing on the expertise of some of Europe's most prominent space institutions in order to demonstrate key active debris remove (ADR) technologies in a low-cost ambitious manner. The mission will consist of a microsatellite platform (chaser) that ejects 2 CubeSats (targets). These targets will assist with a range of strategically important ADR technology demonstrations including net capture, harpoon capture and vision-based navigation using a standard camera and LiDAR. The chaser will also host a drag sail for orbital lifetime reduction.The mission baseline has been revised to take into account feedback from international and national space policy providers in terms of risk and compliance and a suitable launch option is selected. A launch in 2017 is targeted. The RemoveDEBRIS mission aims to be one of the world's first in-orbit demonstrations of key technologies for active debris removal and is a vital prerequisite to achieving the ultimate goal of a cleaner Earth orbital environment.

Investigation of Flame Blow-Out in a Low Bypass Military Turbofan Engine

Flame blow-out is a serious concern for military gas turbine engines, and maintaining a reliable and stable flame in engine throughout the mission is a great challenge. A low bypass military turbo fan engine is investigated for flame blow-out. The history of the engine and its accessories were reviewed. Flight data were analyzed to confirm the blow-out incident. Air flow passages and engine modules were examined for possible foreign object damages or internal damages and found satisfactory. Analysis of atomizer characteristics showed the shifting of spray cone angle and fuel flow rate close to the lower limits. Blockage of atomizer flow passages and liner front end flares could contribute to flame blow-out. One of the filters in the fuel line found damaged. Significant amount of debris were found inside the fuel control valve. From the investigations and evidences, it was concluded that the engine flame blow-out was due to blockage of fuel flow when the air flow was almost steady. Assessment and control of debris in fuel accessories, the periodicity of inspection, and cleaning are very important for maintaining a stable flame throughout the mission. Also understanding the blow-out mechanism in an aero gas turbine engine during maneuvers is necessary to address blow-out issues.

Effect of longer battery life on small bowel capsule endoscopy.

To determine if longer battery life improves capsule endoscopy (CE) completion rates. A retrospective study was performed at a tertiary, university-affiliated hospital in Vancouver, Canada. Patients who underwent CE with either PillCam™ SB2 or SB2U between 01/2010 and 12/2013 were considered for inclusion. SB2 and SB2U share identical physical dimensions but differ in their battery lives (8 h vs 12 h). Exclusion criteria included history of gastric or small bowel surgery, endoscopic placement of CE, interrupted view of major landmarks due to technical difficulty or significant amount of debris, and repeat CE using same system. Basic demographics, comorbidities, medications, baseline bowel habits, and previous surgeries were reviewed. Timing of major landmarks in CE were recorded, and used to calculate gastric transit time, small bowel transit time, and total recording time. A complete CE study was defined as visualization of cecum. Transit times and completion rates were compared. Four hundred and eight patients, including 208 (51.0%) males, were included for analysis. The mean age was 55.5 ± 19.3 years. The most common indication for CE was gastrointestinal bleeding (n = 254, 62.3%), followed by inflammatory bowel disease (n = 86, 21.1%). There was no difference in gastric transit times (group difference 0.90, 95%CI: 0.72-1.13, P = 0.352) and small bowel transit times (group difference 1.07, 95%CI: 0.95-1.19, P = 0.261) between SB2U and SB2, but total recording time was about 14% longer in the SB2U group (95%CI: 10%-18%, P < 0.001) and there was a corresponding trend toward higher completion rate (88.2% vs 93.2%, OR = 1.78, 95%CI 0.88-3.63, P = 0.111). There was no statistically significant difference in the rates of positive findings (OR = 0.98, 95%CI: 0.64-1.51, P = 0.918). Extending the operating time of CE may be a simple method to improve completion rate although it does not affect the rate of positive findings.

A MANAGEMENT OF ADHESIVE DRILLING FLUID PROPERTIES ON A WELL SINKING INTO CLAY DEPOSITS

The authors had considered in the article causes destabilization lithified clay rocks (mudstone and claystone-like) and the formation sticking of the bit in unlithified leck in the field of the Timan-Pechora province and Western Siberia on the basis of the literature, own experimental research and field material. Physico-chemical processes of reaction between the contacting surfaces (adhesion) are one of the reasons and in that in both cases. Adhesive interactions in the rock provide stability clay shale which is characterized slabby, thinly laminated structure with exspressed slip plane, the presence of chaotic microcracks and significant amount of debris. The authors give recommendation about integrated use of clay by applying organic and inorganic inhibitor and technical carbon (for example, carbon black), witch increase the adhesive interaction between the individual ratchet of clay rocks on the basis of own laboratory research besides generally accepted methods preservation of stability claystone-like (inhibiting, hydrophobization, wall packing). The probability of forming cake intensifies in haz-lithified clay from plastic deformation clay rock to form a sealing contact with the surfaces of the bit or steel tubes. The authors conducted a complex research in the laboratory, which has allowed to develop a series of recommendations to be considered at the opening of plastic smectite clay. Except for a general increase in lubricating efficiency drilling mud, necessary to limit the content of the colloidal phase (MBT 3.5 kg/m 3 ) in the presence of a potassium chloride at a concentration of not less than 80 kg/m 3 to reduce the intensity of the adhesive interactions with the components of the drilling mud and metal surfaces (the formation of the cake).

Cave development by frost weathering

This paper deals with the description and genesis of a special type of shelter cave. In German they are termed Auswitterungshöhlen which goes back to the 19th century and the genesis is supposed to be related to frost weathering, but to our knowledge, detailed studies are missing so far. This type of cave is very common in the area of investigation that comprises pre-Alpine and Alpine regions in the north-eastern part of the Eastern Alps: They make up 32% of the 5138 registered caves but surprisingly they entirely developed in carbonate rocks. Although most of them are smaller than a dozen metres, some have lengths of more than 50m and entrances can be more than 100m wide or similarly high. Besides general observations that lead to a list of characteristics for these caves, two of them in a pre-Alpine setting were studied in-depth. A detailed map, descriptions, and measurements concerning cave morphology, host rock geology, and climate are given. The thickness and composition of clastic sediments were investigated by small trenches and electric resistivity measurements. Sediment thicknesses reach up to 2m inside the caves and below the entrances. For one year nets were installed to measure rockfall in both caves. In warm periods generally less than 5g/month of debris could be collected, but a few 100g/month for frost periods. This strong correlation and the significant amount of debris together with other observations suggest that frost weathering is an on-going and very important process for the formation of these caves. Grain-size distribution of the collected debris argues for the activity of both microgelivation and ice segregation. Therefore we suggest that the term frost weathering caves should be used for shelter caves whose genesis is related to frost weathering. As dissolution seems to be of marginal importance for the genesis they are a paradox as they develop in karstic rock but have pseudokarst features.

Design of Gelled Fluid for Debris Removal in Subsea Pipeline

Summary Transportation of hydrocarbon through a pipeline may be hindered as a result of deposition of debris. The presence of debris within the pipeline leads to reduction in the effective flow area, thus reducing the efficiency of the transportation system. Some of the factors leading to formation of the debris are changes in temperature and/or pressure of the transported fluid and chemical reactions, which occur therein. Pipeline-maintenance pigging is performed routinely to extend the operational life of pipelines. Recently, a combination of mechanical and chemical remedial measures has shown beneficial results in pipeline cleaning. Mechanical-brush pigs loosen the debris adhering to the walls, while chemical techniques, such as the use of gelled fluids, enhance the carrying capacity and help to transport the loosened debris out of the pipeline. This paper presents the results of tests conducted to design a fast-breaking gelled fluid for a debris-removal operation in a long, large-diameter subsea pipeline in the Asia Pacific region. In addition to exhibiting good stability and debris-carrying capacity under the laboratory test and field conditions, the gel had to be compatible and demonstrate stability when mixed with other additives in the transported hydrocarbon. A highly viscous, aqueous-based linear polysaccharide gel was designed to satisfy these requirements. A key environmental and operational consideration was the easy and fast disposal of the gel after completion of the cleaning operation. With oxidizing breaker, gels prepared in potable water resulted in viscosity of &amp;lt; 10 cp within 2 days, which was significantly shorter than when seawater-based gels were treated similarly. Preliminary field results indicate that the combined mechanical and gel system removed a significant amount of debris. Data from future trials will help evaluate the feasibility of such a technique for effective cleaning of the pipeline.

Analysis of third body particles generated during total knee arthroplasty: Is metal debris an issue?

PurposeThere is a concern amongst knee surgeons that during total knee arthroplasty (TKA) certain particles could be generated which might become left inside the knee, and which could become a possible cause of third body wear. Especially during the sawing process, when an oscillating saw is used through slots in a cutting block, there is a potential cause for metal debris generation. So far however, no data exist to substantiate and quantify the amount of metal debris left in situ after TKA, and it was the purpose of this study to evaluate this. MethodsIn seven consecutive patients undergoing primary cemented TKA, we measured the amount of debris that was present at the end of the operation immediately before closure. The debris was retrieved using pulsed irrigation with 1 l of normal saline, which was then collected and centrifuged. Obtained pellets were subsequently washed and chemically treated to quantify the different components present in the debris. ResultsOverall an average amount of 134.9 mg (range 73.6–198.0 mg) debris was retrieved. The debris contained on average 75.8 mg of bone particles (range 41.2–109.3 mg), 57.2 mg (range 31.2–83.9 mg) of cement particles, and 1.96 mg (range 0–7.2 mg) of metal particles. On average the total amount of debris consisted for 56.5% of bony fragments, 42% cement fragments and 1.5% metal particles. ConclusionEven despite precise surgical technique including pressurized irrigation, a significant amount of debris is still present after TKA. The debris consists predominantly of bone and cement particles. The presence of metal debris is limited, and contributes only 1.5% to the total amount.

Inhibition of UVA‐induced c‐Jun N‐terminal Kinase Activity Results in Caspase‐dependent Apoptosis in Human Keratinocytes

Inhibition of c-Jun N-terminal kinase (JNK) with the pharmacologic inhibitor SP600125 in UVA-irradiated HaCaT cells and human primary keratinocytes resulted in dramatic phenotypic changes indicative of cell death. These phenotypic changes correlated with caspase 8, 9 and 3 activations as well as cleavage of the caspase substrate polyADP-ribose polymerase (PARP). Morphologic analysis and analysis of sub-G0 DNA content confirmed apoptotic cell death in these keratinocytes after combination treatment. Addition of the general caspase inhibitor zVAD-fmk to combination-treated HaCaT cells was able to completely block caspase activation, PARP cleavage, the increase in sub-G0 DNA content and the classic morphologic features of apoptosis, indicating that this combination treatment resulted in caspase-dependent apoptotic cell death. zVAD-fmk treatment of primary keratinocytes was able to completely inhibit caspase activation and PARP cleavage, reduce morphologic apoptosis at lower concentrations of SP600125 and decrease the sub-G(0) DNA content detected after UVA + SP600125 treatment. However, cell death and a significant amount of debris was still detected after caspase inhibitor treatment, particularly with 125 nM SP600125. At subconfluent conditions and low passage, primary keratinocytes were more sensitive to UVA irradiation alone than HaCaT cells. In conclusion, we have observed that inhibition of UVA-induced JNK activity with the pharmacologic inhibitor SP600125 resulted in caspase-dependent apoptotic cell death in both the immortalized keratinocyte cell line HaCaT and primary keratinocytes. However, the increased sensitivity of primary keratinocytes to experimental stress may have also resulted in direct cellular injury and caspase-independent cell death.

WEAR OF POLYETHYLENE IN ARTIFICIAL HIP JOINTS: SUPEROLATERAL WEAR OF THE ACETABULUM

The bearing couple of a polyethylene acetabular cup and a polished metal or ceramic femoral head has been a successful combination in hip arthroplasty for over 30 years, but it is now recognised that fine micron and submicron polyethylene wear particles can cause adverse cellular reactions which may lead to osteolysis and loosening. In prostheses showing high wear, the penetration of the femoral head into the acetabular cup often exceeds 2 mm after 10 to 15 years. Although the head does not wear through the cup, which may be over 8 mm thick, there is a significant amount of debris, typically over 600 mm. Most of these particles are less than a micron, and therefore in the size range for phagocytosis, resulting in inflammatory reactions and osteolysis. Recent studies of failed Charnley prostheses at 10 to 20 years have estimated that well over one thousand billion wear particles (10) are released into the tissue during this period. There is much interest in the wear of polyethylene since it can lead to the failure of hip arthroplasties. Wear, unlike elastic modulus or hardness, is not a specific property of a material but is a result of the system and conditions in which the materials articulate. The simplest laws of wear state that the volume produced is proportional to the load and the sliding distance, but many other factors dramatically affect the wear rate. These include: 1) Local damage or roughening of the polished femoral head. 2) Oxidative degradation after sterilisation by gamma irradiation in the presence of oxygen (p. 340 and Besong et al). 3) Multidirectional movement. Polyethylene molecules are orientated by the forces of friction in the primary direction concern. Until there is good evidence that the intra-articular procedure alone is as effective as a combined reconstruction there must be doubt about its continued use. In this respect, the longer-term results of the cohort described by Webb et al are of particular interest.