SEARCH · Search NASA
Results for “CAS”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Targeted Assembly of cas Gene Clusters from High Throughput Sequencing Data.
Abstract not provided.
Closure Report for Corrective Action Unit 548: Areas 9, 10, 18, 19, and 20 Housekeeping Sites, Nevada National Security Site, Nevada
This Closure Report (CR) documents closure activities for Corrective Action Unit (CAU) 548, Areas 9, 10, 18, 19, and 20 Housekeeping Sites, and complies with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the State of Nevada; the U.S. Department of Energy (DOE), Environmental Management; the U.S. Department of Defense; and DOE, Legacy Management (FFACO, 1996 as amended). CAU 548 consists of the following Corrective Action Sites (CASs), located in Areas 9, 10, 12, 18, 19, and 20 of the Nevada National Security Site: · CAS 09-99-02, Material Piles (2) · CAS 09-99-04, Wax, Paraffin · CAS 09-99-05, Asbestos, Vermiculite · CAS 09-99-07, Tar Spill · CAS 10-22-02, Drums · CAS 10-22-05, Gas Block · CAS 10-22-07, Gas Block · CAS 10-22-34, Drum · CAS 10-22-38, Drum; Cable · CAS 12-99-04, Epoxy Tar Spill · CAS 12-99-08, Cement Spill · CAS 18-14-01, Transformers (3) · CAS 19-22-01, Drums · CAS 19-22-11, Gas Block (2) · CAS 19-44-01, Fuel Spill · CAS 20-22-07, Drums (2) · CAS 20-22-09, Drums (3) · CAS 20-22-14, Drums (2) · CAS 20-22-16, Drums (2) · CAS 20-24-09, Battery Closure activities began in July 2011 and were completed in December 2011 and included removal and disposal of material piles, spills, sanitary debris, a lead acid battery, lead and steel shot, and stained soil. Activities were conducted according to the Sectored Clean-up Work Plan for Housekeeping Category Waste Sites (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSA/NSO], 2003). Closure activities generated sanitary waste, hydrocarbon waste, low-level waste, hazardous waste, and mixed waste. Some wastes exceeded land disposal limits and required offsite treatment prior to disposal. Other wastes met land disposal restrictions and were disposed in appropriate onsite or offsite landfills. NNSA/NSO requests the following: · A Notice of Completion from the Nevada Division of Environmental Protection to NNSA/NSO for closure of CAU 548 · The transfer of CAU 548 from Appendix III to Appendix IV, Closed Corrective Action Units, of the FFACO
Corrective Action Decision Document/Closure Report for Corrective Action Unit 561: Waste Disposal Areas, Nevada National Security Site, Nevada, Revision 0 with ROTC 1
CAU 561 comprises 10 CASs: (1) 01-19-01, Waste Dump; (2) 02-08-02, Waste Dump and Burn Area; (3) 03-19-02, Debris Pile; (4) 05-62-01, Radioactive Gravel Pile; (5) 12-23-09, Radioactive Waste Dump; (6) 22-19-06, Buried Waste Disposal Site; (7) 23-21-04, Waste Disposal Trenches ; (8) 25-08-02, Waste Dump; (9) 25-23-21, Radioactive Waste Dump; and (10) 25-25-19, Hydrocarbon Stains and Trench. The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure of CAU 561 with no further corrective action. The purpose of the CAI was to fulfill the following data needs as defined during the DQO process: (1) Determine whether COCs are present; (2) If COCs are present, determine their nature and extent; and (3) Provide sufficient information and data to complete appropriate corrective actions. The following contaminants were determined to be present at concentrations exceeding their corresponding FALs: (1) No contamination exceeding FALs was identified at CASs 01-19-01, 03-19-02, 05-62-01, 12-23-09, and 22-19-06. (2) The surface and subsurface soil within the burn area at CAS 02-08-02 contains arsenic and lead above the FALs of 23 milligrams per kilogram (mg/kg) and 800 mg/kg, respectively. The surface and subsurface soil within the burn area also contains melted lead slag (potential source material [PSM]). The soil within the waste piles contains polyaromatic hydrocarbons (PAHs) above the FALs. The contamination within the burn area is spread throughout the area, as it was not feasible to remove all the PSM (melted lead), while at the waste piles, the contamination is confined to the piles. (3) The surface and subsurface soils within Trenches 3 and 5 at CAS 23-21-04 contain arsenic and polychlorinated biphenyls (PCBs) above the FALs of 23 mg/kg and 0.74 mg/kg, respectively. The soil was removed from both trenches, and the soil that remains at this CAS does not contain contamination exceeding the FALs. Lead bricks and counterweights were also removed, and the soil below these items does not contain contamination that exceeds the FAL for lead. (4) The concrete-like material at CAS 25-08-02 contains arsenic above the FAL of 23 mg/kg. This concrete-like material was removed, and the soil that remains at this CAS does not contain contamination exceeding the FALs. Lead-acid batteries were also removed, and the soil below the batteries does not contain contamination that exceeds the FAL for lead. (5) The surface soils within the main waste dump at the posted southern radioactive material area (RMA) at CAS 25-23-21 contain cesium (Cs)-137 and PCBs above the FALs of 72.9 picocuries per gram (pCi/g) and 0.74 mg/kg, respectively. The soil was removed from the RMA, and the soil that remains at this CAS does not contain contamination exceeding the FALs. (6) The surface and subsurface soils at CAS 25-25-19 do not contain contamination exceeding the FALs. In addition, lead bricks were removed, and the soil below these items does not contain contamination that exceeds the FAL for lead. The following best management practices were implemented: (1) Housekeeping debris at CASs 02-08-02, 23-21-04, 25-08-02, 25-23-21, and 25-25-19 was removed and disposed of; (2) The open trenches at CAS 23-21-04 were backfilled; (3) The waste piles at CAS 25-08-02 were removed and the area leveled to ground surface; and (4) The remaining waste piles at the main waste dump at CAS 25-23-21 were leveled to ground surface. Therefore, NNSA/NSO provides the following recommendations: (1) No further action for CASs 01-19-01, 03-19-02, 05-62-01, 12-23-09, and 22-19-06; (2) Closure in place with an FFACO use restriction (UR) at CAS 02-08-02 for the remaining PAH-, arsenic-, and lead-contaminated soil, and the melted lead PSM. The UR form and map have been filed in the NNSA/NSO Facility Information Management System, the FFACO database, and the NNSA/NSO CAU/CAS files; (3) No further corrective action at CAS 23-21-04, as the lead bricks and counterweights (PSM) have been removed, and the COCs of arsenic and PCBs in soil have been removed; (4) No further corrective action at CAS 25-08-02, as the COC of arsenic in soil has been removed, and the lead-acid batteries have been removed; (5) No further corrective action at CAS 25-23-21, as the COCs of Cs-137 and PCBs in soil have been removed, and the cast-iron pipes have been removed and disposed of; (6) No further corrective action at CAS 25-25-19, as the lead bricks (PSM) been removed; (7) A Notice of Completion to the NNSA/NSO is requested from the Nevada Division of Environmental Protection for closure of CAU 561; and (8) Corrective Action Unit 561 should be moved from Appendix III to Appendix IV of the FFACO.
Closure Report for Corrective Action Unit 104: Area 7 Yucca Flat Atmospheric Test Sites, Nevada National Security Site, Nevada
This Closure Report (CR) presents information supporting closure of Corrective Action Unit (CAU) 104, Area 7 Yucca Flat Atmospheric Test Sites, and provides documentation supporting the completed corrective actions and confirmation that closure objectives for CAU 104 were met. This CR complies with the requirements of the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the State of Nevada; the U.S. Department of Energy (DOE), Environmental Management; the U.S. Department of Defense; and DOE, Legacy Management. CAU 104 consists of the following 15 Corrective Action Sites (CASs), located in Area 7 of the Nevada National Security Site: · CAS 07-23-03, Atmospheric Test Site T-7C · CAS 07-23-04, Atmospheric Test Site T7-1 · CAS 07-23-05, Atmospheric Test Site · CAS 07-23-06, Atmospheric Test Site T7-5a · CAS 07-23-07, Atmospheric Test Site - Dog (T-S) · CAS 07-23-08, Atmospheric Test Site - Baker (T-S) · CAS 07-23-09, Atmospheric Test Site - Charlie (T-S) · CAS 07-23-10, Atmospheric Test Site - Dixie · CAS 07-23-11, Atmospheric Test Site - Dixie · CAS 07-23-12, Atmospheric Test Site - Charlie (Bus) · CAS 07-23-13, Atmospheric Test Site - Baker (Buster) · CAS 07-23-14, Atmospheric Test Site - Ruth · CAS 07-23-15, Atmospheric Test Site T7-4 · CAS 07-23-16, Atmospheric Test Site B7-b · CAS 07-23-17, Atmospheric Test Site - Climax Closure activities began in October 2012 and were completed in April 2013. Activities were conducted according to the Corrective Action Decision Document/Corrective Action Plan for CAU 104. The corrective actions included No Further Action and Clean Closure. Closure activities generated sanitary waste, mixed waste, and recyclable material. Some wastes exceeded land disposal limits and required treatment prior to disposal. Other wastes met land disposal restrictions and were disposed in appropriate onsite landfills. The U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO) requests the following: · A Notice of Completion from the Nevada Division of Environmental Protection to NNSA/NFO for closure of CAU 104 · The transfer of CAU 104 from Appendix III to Appendix IV, Closed Corrective Action Units, of the FFACO
Corrective Action Plan for Corrective Action Unit 562: Waste Systems, Nevada National Security Site, Nevada
This Corrective Action Plan has been prepared for Corrective Action Unit (CAU) 562, Waste Systems, in accordance with the Federal Facility Agreement and Consent Order (1996; as amended March 2010). CAU 562 consists of 13 Corrective Action Sites (CASs) located in Areas 2, 23, and 25 of the Nevada National Security Site. Site characterization activities were performed in 2009 and 2010, and the results are presented in Appendix A of the Corrective Action Decision Document for CAU 562. The scope of work required to implement the recommended closure alternatives is summarized. (1) CAS 02-26-11, Lead Shot, will be clean closed by removing shot. (2) CAS 02-44-02, Paint Spills and French Drain, will be clean closed by removing paint and contaminated soil. As a best management practice (BMP), asbestos tile will be removed. (3) CAS 02-59-01, Septic System, will be clean closed by removing septic tank contents. As a BMP, the septic tank will be removed. (4) CAS 02-60-01, Concrete Drain, contains no contaminants of concern (COCs) above action levels. No further action is required; however, as a BMP, the concrete drain will be removed. (5) CAS 02-60-02, French Drain, was clean closed. Corrective actions were completed during corrective action investigation activities. As a BMP, the drain grates and drain pipe will be removed. (6) CAS 02-60-03, Steam Cleaning Drain, will be clean closed by removing contaminated soil. As a BMP, the steam cleaning sump grate and outfall pipe will be removed. (7) CAS 02-60-04, French Drain, was clean closed. Corrective actions were completed during corrective action investigation activities. (8) CAS 02-60-05, French Drain, will be clean closed by removing contaminated soil. (9) CAS 02-60-06, French Drain, contains no COCs above action levels. No further action is required. (10) CAS 02-60-07, French Drain, requires no further action. The french drain identified in historical documentation was not located during corrective action investigation activities. (11) CAS 23-60-01, Mud Trap Drain and Outfall, will be clean closed by removing sediment from the mud trap. As a BMP, the mud trap and outfall pipe will be removed. (12) CAS 23-99-06, Grease Trap, will be clean closed by removing sediment from the grease trap and backfilling the grease trap with grout. (13) CAS 25-60-04, Building 3123 Outfalls, will be clean closed by removing contaminated soil and the sludge-containing outfall pipe.
Comparison of Endovascular and Open Carotid Artery Treatment in Germany: A Retrospective Analysis from 2010 to 2015
Introduction: We analyzed trends in carotid artery stenting (CAS) and carotid endarterectomy (CEA) in hospitalized cases in Germany in the years 2010–2015. Methods: Data from national statistics (DRG statistics) published by the Federal Statistical Office in Germany describing the number of hospitalized patients treated with CEA and CAS were used. In addition, numbers of patients hospitalized with the principal diagnosis stroke associated with precerebral lesions (ICD code I63), transitory cerebral ischemic attacks (G45) and precerebral carotid artery stenosis (I65) treated by CEA and CAS were analyzed for the year 2015. Results: Total number of CEA decreased by 4.0% from 24.067 (2010) to 23.104 (2015) and CAS increased by 5.1% from 5.703 to 5.992. In 2015, 79.4% of all procedures coded concerning the internal carotid artery were CEA and 21.6% CAS. From 27.798 cases hospitalized with the principal diagnosis stroke associated with precerebral lesions, CEA was performed in 3.921 (14.1%) and in 2.132 (7.7%) CAS was documented, with CAS making up one-third of all treatments within the stroke group. In 28.273 cases hospitalized with a TIA, CEA was specified in 853 (3.0%) and CAS in 255 (0.9%) cases. In 27.553 cases with an occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction, 17.036 (61.8%) had a CEA and 3.156 (11.5%) a CAS procedure. Conclusion: CEA is still the primary treatment of extracranial artery stenosis. The impact of CAS becomes mainly apparent in cases presenting with acute strokes.
Sulfur isotope fractionation between aqueous and carbonate-associated sulfate in abiotic calcite and aragonite
Sulfate (SO 4 2– ) incorporated into calcium carbonate minerals enables measurements of sulfur (S) isotope ratios in carbonate rocks. This Carbonate Associated Sulfate (CAS) in marine carbonate minerals is thought to faithfully represent the S isotope composition of the seawater sulfate incorporated into the mineral, with little or no S isotope fractionation in the process. However, comparison between different calcifying species reveals both positive and negative S isotope fractionation between CAS and seawater sulfate, and a large range of S isotope ratios can be found within a single rock sample, depending on the component measured. To better understand the isotopic effects associated with sulfate incorporation into carbonate minerals, we precipitated inorganic calcite and aragonite over a range covering more than two orders of magnitude of sulfate concentration and precipitation rate. Coupled measurements of CAS concentration, S isotope composition and X-ray absorption near-edge spectra (XANES) permit characterization and explanation of the observed dependence of S isotope fractionation between CAS and aqueous sulfate (CAS-SO 4 2– isotope fractionation) on sulfate concentration and precipitation rate. In aragonite, the CAS-SO 4 2– isotope fractionation is 1.0 ± 0.3‰ and independent of the sulfate (and CAS) concentration. In contrast, we note the CAS-SO 4 2– isotope fractionation in calcite covaries strongly with the sulfate concentration and weakly with the precipitation rate, between values of 1.3 ± 0.1 and 3.1 ± 0.6‰. We suggest that the correlation between aqueous sulfate concentration and CAS-SO 4 2– isotope fractionation in calcite reflects a dependence of the equilibrium S isotope fractionation on the concentration of CAS, through the effect of the sulfate impurity on the carbonate mineral’s energetic state.
Structure of soybean [beta]-cyanoalanine synthase and the molecular basis for cyanide detoxification in plants
Plants produce cyanide (CN{sup -}) during ethylene biosynthesis in the mitochondria and require {beta}-cyanoalanine synthase (CAS) for CN{sup -} detoxification. Recent studies show that CAS is a member of the {beta}-substituted alanine synthase (BSAS) family, which also includes the Cys biosynthesis enzyme O-acetylserine sulfhydrylase (OASS), but how the BSAS evolved distinct metabolic functions is not understood. Here we show that soybean (Glycine max) CAS and OASS form {alpha}-aminoacrylate reaction intermediates from Cys and O-acetylserine, respectively. To understand the molecular evolution of CAS and OASS in the BSAS enzyme family, the crystal structures of Gm-CAS and the Gm-CAS K95A mutant with a linked pyridoxal phosphate (PLP)-Cys molecule in the active site were determined. These structures establish a common fold for the plant BSAS family and reveal a substrate-induced conformational change that encloses the active site for catalysis. Comparison of CAS and OASS identified residues that covary in the PLP binding site. The Gm-OASS T81M, S181M, and T185S mutants altered the ratio of OASS:CAS activity but did not convert substrate preference to that of a CAS. Generation of a triple mutant Gm-OASS successfully switched reaction chemistry to that of a CAS. This study provides new molecular insight into the evolution of diverse enzyme functions across the BSAS family in plants.
STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. II. EPISODIC FORMATION OF BROAD-LINE REGIONS
This is the second in a series of papers discussing the process and effects of star formation in the self-gravitating disk around the supermassive black holes in active galactic nuclei (AGNs). We have previously suggested that warm skins are formed above the star-forming (SF) disk through the diffusion of warm gas driven by supernova explosions. Here we study the evolution of the warm skins when they are exposed to the powerful radiation from the inner part of the accretion disk. The skins initially are heated to the Compton temperature, forming a Compton atmosphere (CAS) whose subsequent evolution is divided into four phases. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS because of the CAS overdensity driven by continuous injection of warm gas from the SF disk. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of broad-line regions (BLRs). We follow the formation of cold clouds through the thermal instability of the CAS during phases II and III, using linear analysis. Since the clouds are produced inside the CAS, the initial spatial distribution of newly formed clouds and angular momentum naturally follow the CAS dynamics, producing a flattened disk of clouds. The number of clouds in phases II and III can be estimated, as well as the filling factor of clouds in the BLR. Since the cooling function depends on the metallicity, the metallicity gradients that originate in the SF disk give rise to different properties of clouds in different radial regions. We find from the instability analysis that clouds have column density N{sub H} {approx}< 10{sup 22} cm{sup -2} in the metal-rich regions whereas they have N{sub H} {approx}> 10{sup 22} cm{sup -2} in the metal-poor regions. The metal-rich clouds compose the high-ionization line regions whereas the metal-poor clouds are in low-ionization line (LIL) regions. Since metal-rich clouds are optically thin, they will be blown away by radiation pressure, forming the observed outflows. The outflowing clouds could set up a metallicity correlation between the BLRs and narrow-line regions. The LIL regions are episodic due to the mass cycle of clouds with the CAS in response to continuous injection by the SF disk, giving rise to different types of AGNs. Based on Sloan Digital Sky Survey quasar spectra, we identify a spectral sequence in light of emission-line equivalent width from phase I to IV. A key phase in the episodic appearance of the BLRs is bright type II AGNs with no or only weak BLRs, contrary to the popular picture in which the absence of a BLR is due to a low accretion rate. We discuss observational implications and tests of the theoretical predictions of this model.
Addendum 2 to the Closure Report for CAU 577 Area 5 Chromium Containing Waste Disposal Cells, NNSS, Nevada
Corrective Action Unit (CAU) 577, “Area 5 Chromium Containing Waste Disposal Cells,” includes five low-level waste cells at the Nevada National Security Site Area 5 Radioactive Waste Management Site where buried waste received from Nuclear Fuel Services, Inc., was subsequently determined to contain chromium that exceeded the toxicity characteristic leaching procedure regulatory limit, which would require the waste to carry hazardous waste code D007. CAU 577 was created to satisfy the requirements of the Settlement Agreement (SA) executed between the Nevada Division of Environmental Protection (NDEP) and the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO) on April 25, 2019 (NDEP 2019). The SA required that the chromium-containing waste received from NFS would be addressed following the closure process laid out in the Federal Facility Agreement and Consent Order (FFACO). The FFACO process ensures proper closure of the chromium-containing waste and documentation of that closure through FFACO-type documents. The following three Corrective Action Sites (CASs) were closed, and their closure was documented in the Closure Report for Corrective Action Unit 577: Area 5 Chromium Containing Waste Disposal Cells, Nevada National Security Site, Nevada, DOE/EMNV--0030, dated September 2021 (U.S. Department of Energy [DOE] Environmental Management [EM] Nevada Program 2021a): • CAS 05-21-02, Waste Disposal Cell 12 • CAS 05-21-03, Waste Disposal Cell 15 • CAS 05-21-04, Waste Disposal Cell 17 Closure of the following CAS was previously documented in the Addendum to the Closure Report for Corrective Action Unit 577: Area 5 Chromium Containing Waste Disposal Cells, Nevada National Security Site, Nevada, DOE/EMNV--0030-ADD, dated September 2022 (DOE EM Nevada Program 2022): • CAS 05-21-05, Waste Disposal Cell 20 This second addendum to the Closure Report documents the closure activities that have occurred for CAS 05-21-06, Waste Disposal Cell 21. This is the last CAS in CAU 577. The final waste shipment was placed in the waste disposal cell on November 21, 2022. Following this, closure activities began on November 28, 2022, and were conducted according to the Corrective Action Decision Document/Corrective Action Plan (CADD/CAP) for CAU 577 (DOE EM Nevada Program 2021b). The following closure activities were performed: • Constructing an engineered evapotranspiration cover • Installing two subsidence monuments and vadose zone monitoring equipment • Seeding the cover with a mixture of native plant species • Installing four concrete monuments on the corners of the cover and placing two use restriction (UR) warning signs on each monument These activities fulfill applicable federal and state regulations for closure of CAS 05-21-06 and minimize potential future exposure pathways to buried waste. Completed closure activities are also consistent with closure of the nine historical Resource Conservation and Recovery Act (RCRA) units included in Section 10.2.2 of the RCRA Permit that governs hazardous waste management activities at the Nevada National Security Site (Permit NEV HW0101) (NDEP 2023). UR documentation for this CAS is included in Appendix B of this report. The post-closure plan is presented in detail in the CADD/CAP for CAU 577 (DOE EM Nevada Program 2021b), and the requirements are summarized in Section 5.2 of this document. In accordance with paragraph 5D of the SA, a request to incorporate the requirements for post-closure monitoring of CAU 577 was included with the permit application for RCRA Permit NEV HW0101 that was submitted in January 2022 (NNSA/NFO 2022). The request included the post-closure requirements for the three CASs that had been closed at the time of submittal of the application as well as requirements that would be implemented upon future approval of closure of the remaining two CASs. All CAU 577 post-closure monitoring requirements have been captured in the April 4, 2023, Revision 7 of the RCRA Permit (NDEP 2023). As the RCRA Permit NEV HW0101 has been revised since the submittal of the original CAU 577 Closure Report (DOE EM Nevada Program 2021a) and Addendum 1 (DOE EM Nevada Program 2022), the post-closure requirements in this Addendum 2 report do not align with the previous documents. Specific changes resulting from the issuance of Revision 7 of the RCRA Permit are discussed in Section 5.2 of this report. The requirements in this report are consistent with the current permit (NDEP 2023) and supersede all requirements listed in the CAU 577 Closure Report and Addendum 1. All CAU 577 post-closure requirements should be conducted in accordance with the version of the RCRA Permit that is current at the time of the activities being performed. The DOE EM Nevada Program is requesting a Notice of Completion from NDEP for closure of CAU 577. Although CAU 577 is not a legacy site, the FFACO process is being followed to ensure proper closure of the chromium-containing waste. Therefore, transfer of CAU 577 from Appendix III of the FFACO to Appendix IV, Closed Corrective Action Units, is requested, as all closure activities have been completed.
Criticality Alarm Systems at the Idaho Chemical Processing Plant
The Idaho Chemical Processing Plant (ICPP) has a number of criticality alarm systems (CAS) in the various facilities. The complexity of the plant creates some unique CAS problems. A detailed review of the CAS has been made to determine the level of compliance with ANSI 8.3-1986. A major CAS upgrade project is currently in the design stage which will expand coverage and bring all CAS monitoring unshielded areas into full compliance with ANSI 8.3-1986. Because DOE Orders do not contain an exclusion that exempts the need for CAS coverage in shielded areas as provided in ANSI 8.3-1986, a future CAS upgrade project is in the planning stage which will also upgrade the CAS coverage in shielded portions of the plant.
Cerebrospinal Fluid Enhancement on Fluid Attenuated Inversion Recovery Images After Carotid Artery Stenting with Neuroprotective Balloon Occlusions: Hemodynamic Instability and Blood-Brain Barrier Disruption
Purpose: A rare complication of carotid artery stenting (CAS), prolonged reversible neurological symptoms with delayed cerebrospinal fluid (CSF) space enhancement on fluid attenuated inversion recovery (FLAIR) images, is associated with blood-brain barrier (BBB) disruption. We prospectively identified patients who showed CSF space enhancement on FLAIR images. Methods: Nineteen patients-5 acute-phase and 14 scheduled-underwent 21 CAS procedures. Balloon catheters were navigated across stenoses, angioplasty was performed using a neuroprotective balloon, and stents were placed with after dilation under distal balloon protection. CSF space hyperintensity or obscuration on FLAIR after versus before CAS indicated CSF space enhancement. Correlations with clinical factors were examined. Results: CSF space was enhanced on FLAIR in 12 (57.1%) cases. Postprocedural CSF space enhancement was significantly related to age, stenosis rate, acute-stage procedure, and total occlusion time. All acute-stage CAS patients showed delayed enhancement. Only age was associated with delayed CSF space enhancement in scheduled CAS patients. Conclusions: Ischemic intolerance for severe carotid artery stenosis and temporary neuroprotective balloon occlusion, causing reperfusion injury, seem to be the main factors that underlie BBB disruption with delayed CSF space enhancement shortly after CAS, rather than sudden poststenting hemodynamic change. Our results suggest that factors related to hemodynamic instability or ischemic intolerance seem to be associated with post-CAS BBB vulnerability. Patients at risk for hemodynamic instability or with ischemic intolerance, which decrease BBB integrity, require careful management to prevent intracranial hemorrhagic and other post-CAS complications.
Acute Carotid Artery Stent Thrombosis Due to Dual Antiplatelet Resistance
Carotid artery stenting (CAS) is a revascularization modality that is an alternative to carotid endarterectomy. The efficacy of CAS in primary and secondary prevention from ischemic stroke has been demonstrated in various trials. Acute thrombosis of CAS is a rare complication that can lead to dramatic and catastrophic consequences. We discuss a case of acute CAS thrombosis in a patient who had previously undergone successful CAS. CAS was performed in a 73-year-old man who had had dysarthria lasting 2 weeks with 95 % stenosis in his left internal carotid artery. An acute cerebrovascular event resulting in right-sided hemiplegia developed 24 h after the procedure. Computed tomographic carotid angiography revealed complete occlusion of the stent with thrombus. The cause of stent thrombosis was thought to be antiaggregant resistance to both acetylsalicylic acid and clopidogrel. The most important cause of acute CAS thrombosis is inadequate or ineffective antiaggregant therapy. Evaluating patients who are candidates for CAS for acetylsalicylic acid and clopidogrel resistance may preclude this complication.
Inclusion Characterization in Aluminum-Deoxidized Special Steel with Certain Sulfur Content Under Combined Influences of Slag Refining, Calcium Treatment, and Reoxidation
Inclusions in Al-killed steel with [S] of about 0.0060 to 0.0070 mass pct were characterized and discussed, evaluating the combined effects of basic slag refining and Ca treatment in ladle, together with reoxidation of liquid steel in casting tundish. Inclusions were changed from Al{sub 2}O{sub 3} to MgO-Al{sub 2}O{sub 3} spinel and then to MgO-Al{sub 2}O{sub 3}-CaO during basic slag refining. After Ca treatment, many (MgO-Al{sub 2}O{sub 3}) + CaS inclusions were formed, featuring the coexistence of MgO-Al{sub 2}O{sub 3} and CaS to form a dual-phased structure. In the following Ar blowing, the number density of (MgO-Al{sub 2}O{sub 3}) + CaS inclusions and pure CaS increased obviously, which implied that [Ca] preferentially reacted with [S] rather than [O] in steel. Reoxidation in casting tundish caused the pickup of oxygen in steel, and the rise of total oxygen (T.O) was 0.0002 mass pct; even 55t steel has been poured. As a result, the content of CaO in inclusions increased and MgO-Al{sub 2}O{sub 3}-CaO inclusions were formed again. Thermodynamic calculations revealed that the driving force was strong for the formation of CaS-based inclusions. Higher carbon content in steel would help to reduce oxygen content while enhancing the activity of [S] in steel, which further stabilized the existence of CaS-based inclusions. Therefore, inclusions were mostly the solid (MgO-Al{sub 2}O{sub 3}) + CaS dual-phase ones, without the formation of liquid calcium aluminates. Contents of CaS and CaO in inclusions were affected by the [mass pct S]/[mass pct O] ratio, which was calculated as about 4.58 K and 5.34 K at 1873 K and 1823 K, respectively. This finding implied that lower oxygen was not favorable to prevent the solid inclusions in the calcium treatment of high carbon special steel.
Aberrant endoplasmic reticulum stress mediates coronary artery spasm through regulating MLCK/MLC2 pathway
Coronary artery spasm (CAS) is a pathophysiological phenomenon that may cause myocardial infarction and lead to circulatory collapse and death. Aberrant endoplasmic reticulum (ER) stress causes accumulation of misfolding proteins and has been reported to be involved in a variety of vascular diseases. The present study investigated the role of ER stress in the development of CAS and explored the possible molecular mechanisms. Initially, it was found that ER stress markers were elevated in response to drug-induced vascular smooth muscle cells (VSMCs) contraction. Pharmacologic activation of ER stress using Tunicamycin (Tm) persistently induced CAS and significantly promoted Pituitrin-induced CAS in mice as well as in a collagen gel contraction assay. On the contrary, pharmacologic inhibition of ER stress using 4-phenylacetic acid (4-PBA) completely blunted Pituitrin-induced CAS development in mice. Moreover, during the drug-induced VSMCs contraction, expression of ER stress markers were increased in parallel to those of myosin light chain kinase (MLCK) and phosphor-MLC2 (p-MLC2, at Ser19). After inhibiting MLCK activity by using its specific inhibitor ML-7, the ER stress activator Tm failed to activate the MLCK/MLC2 pathway and could neither trigger CAS in mice nor induce VSMCs contraction in vitro. Our results suggested that aberrant ER stress mediated CAS via regulating the MLCK/MLC2 pathway. ER stress activators might be more robust than the common drugs (Pituitrin or acetylcholine) as to induce vasocontraction and thus may serve as potential therapeutics against chronic bleeding, while its inhibitor might be useful for treatment of severe CAS caused by other medication.
A universal method for sensitive and cell-free detection of CRISPR-associated nucleases
A multitude of biological applications for CRISPR-associated (Cas) nucleases have propelled the development of robust cell-based methods for quantitation of on- and off-target activities of these nucleases. However, emerging applications of these nucleases require cell-free methods that are simple, sensitive, cost effective, high throughput, multiplexable, and generalizable to all classes of Cas nucleases. Current methods for cell-free detection are cumbersome, expensive, or require sophisticated sequencing technologies, hindering their widespread application beyond the field of life sciences. Developing such cell-free assays is challenging for multiple reasons, including that Cas nucleases are single-turnover enzymes that must be present in large excess over their substrate and that different classes of Cas nucleases exhibit wildly different operating mechanisms. Here, we report the development of a cell-free method wherein Cas nuclease activity is amplified via an in vitro transcription reaction that produces a fluorescent RNA:small-molecule adduct. We demonstrate that our method is sensitive, detecting activity from low nanomolar concentrations of several families of Cas nucleases, and can be conducted in a high-throughput microplate fashion with a simple fluorescent-based readout. We provide a mathematical framework for quantifying the activities of these nucleases and demonstrate two applications of our method, namely the development of a logic circuit and the characterization of an anti-CRISPR protein. We anticipate our method will be valuable to those studying Cas nucleases and will allow the application of Cas nuclease beyond the field of life sciences.
Closure Report for Corrective Action Unit 539: Areas 25 and 26 Railroad Tracks Nevada National Security Site, Nevada with ROTCs 1-2, Revision 0
This Closure Report (CR) presents information supporting the closure of Corrective Action Unit (CAU) 539: Areas 25 and 26 Railroad Tracks, Nevada National Security Site, Nevada. This CR complies with the requirements of the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the State of Nevada; U.S. Department of Energy (DOE), Environmental Management; U.S. Department of Defense; and DOE, Legacy Management. The corrective action sites (CASs) within CAU 539 are located within Areas 25 and 26 of the Nevada National Security Site. Corrective Action Unit 539 comprises the following CASs: • 25-99-21, Area 25 Railroad Tracks • 26-99-05, Area 26 Railroad Tracks The purpose of this CR is to provide documentation supporting the completed corrective actions and provide data confirming that the closure objectives for CASs within CAU 539 were met. To achieve this, the following actions were performed: • Reviewed documentation on historical and current site conditions, including the concentration and extent of contamination. • Conducted radiological walkover surveys of railroad tracks in both Areas 25 and 26. • Collected ballast and soil samples and calculated internal dose estimates for radiological releases. • Collected in situ thermoluminescent dosimeter measurements and calculated external dose estimates for radiological releases. • Removed lead bricks as potential source material (PSM) and collected verification samples. • Implemented corrective actions as necessary to protect human health and the environment. • Properly disposed of corrective action and investigation wastes. • Implemented an FFACO use restriction (UR) for radiological contamination at CAS 25-99-21. The approved UR form and map are provided in Appendix F and will be filed in the DOE, National Nuclear Security Administration Nevada Site Office (NNSA/NSO), Facility Information Management System; the FFACO database; and the NNSA/NSO CAU/CAS files. From November 29, 2010, through May 2, 2011, closure activities were performed as set forth in the Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 539: Areas 25 and 26 Railroad Tracks, Nevada Test Site, Nevada. The purposes of the activities as defined during the data quality objectives process were as follows: • Determine whether contaminants of concern (COCs) are present. • If COCs are present, determine their nature and extent, implement appropriate corrective actions, and properly dispose of wastes. Analytes detected during the closure activities were evaluated against final action levels (FALs) to determine COCs for CAU 539. Assessment of the data generated from closure activities revealed the following: • At CAS 26-99-05, the total effective dose for radiological releases did not exceed the FAL of 25 millirem per Industrial Area year. Potential source material in the form of lead bricks was found at three locations. A corrective action of clean closure was implemented at these locations, and verification samples indicated that no further action is necessary. • At CAS 25-99-21, the total effective dose for radiological releases exceeds the FAL of 25 millirem per Industrial Area year. Potential source material in the form of lead bricks was found at eight locations. A corrective action was implemented by removing the lead bricks and soil above FALs at these locations, and verification samples indicated that no further action is necessary. Pieces of debris with high radioactivity were identified as PSM and remain within the CAS boundary. A corrective action of closure in place with a UR was implemented at this CAS because closure activities showed evidence of remaining soil contamination and radioactive PSM. Future land use will be restricted from surface and intrusive activities. Closure activities generated waste streams consisting of industrial solid waste, recyclable materials, low-level radioactive waste, and mixed low-level radioactive waste. Wastes were disposed of in the appropriate onsite landfills. The NNSA/NSO provides the following recommendations: • Clean closure is required at CAS 26-99-05. • Closure in place is required at CAS 25-99-21. • A UR is required at CAS 25-99-21. • A Notice of Completion to the NNSA/NSO is requested from the Nevada Division of Environmental Protection for closure of CAU 539. • Corrective Action Unit 539 should be moved from Appendix III to Appendix IV of the FFACO.