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Sample records for pseudoaneurysm formation secondary

  1. Subclavian Arteritis and Pseudoaneurysm Formation Secondary to Stent Infection

    SciTech Connect

    Malek, Adel M.; Higashida, Randall T.; Reilly, Linda M.; Smith, Wade S.; Kang, Sang-Mo; Gress, Daryl R.; Meyers, Philip M.; Phatouros, Constantine C.; Halbach, Van V.; Dowd, Christopher F.

    2000-01-15

    Technically uncomplicated percutaneous angioplasty and stent placement of a left subclavian artery stenosis was performed in a 56-year-old man for treatment of subclavian steal syndrome and vertebrobasilar insufficiency. Six days later the patient was readmitted with Staphylococcus aureus bacteremia and stigmata of septic emboli isolated to the ipsilateral hand. Nine days later he had computed tomography (CT) evidence of a contrast-enhancing phlegmon surrounding the stent. Despite clinical improvement and resolution of bacteremia on intravenous antibiotic therapy, the phlegmon progressed, and at day 21 a pseudoaneurysm was angiographically confirmed. The patient underwent surgical removal of the stented arterial segment and successful autogenous arterial reconstruction. The possible contributory factors leading to stent infection were prolonged right femoral artery access and an infected left arm venous access. Although the role of prophylactic antibiotics remains to be defined, it may be important in cases where the vascular access sheath remains in place for a prolonged period of time.

  2. Iatrogenic Femoral Pseudoaneurysm and Secondary Ipsilateral Deep Vein Thrombosis: An Indication for Early Surgical Exploration.

    PubMed

    Papadakis, Marios; Zirngibl, Hubert; Floros, Nikolaos

    2016-07-01

    Pseudoaneurysm formation often complicates transfemoral interventional procedures. Nonsurgical treatment consists of femoral compression and thrombin injection under ultrasound guidance. We report a 74-year-old man who was diagnosed with a pseudoaneurysm, following coronary angiography. Duplex ultrasound revealed deep vein thrombosis of the ipsilateral common femoral vein. Ultrasound-guided thrombin injection was unsuccessfully performed, and the patient subsequently underwent surgical exploration for repair of the pseudoaneurysm and release of the venous compression. The increased local inflammation, because of the thrombosis, added in surgical difficulties. We conclude that early surgical intervention should be considered as a primary strategy in patients with femoral pseudoaneurysms and deep vein thrombosis secondary to femoral compression.

  3. Aortic Pseudoaneurysm Secondary to Mediastinitis due to Esophageal Perforation

    PubMed Central

    Zuluaga, Claudia Patricia; Aluja Jaramillo, Felipe; Velásquez Castaño, Sergio Andrés; Rivera Bernal, Aura Lucía; Granada, Julio Cesar; Carrillo Bayona, Jorge Alberto

    2016-01-01

    Esophageal perforation is a condition associated with high morbidity and mortality rates; it requires early diagnosis and treatment. The most common complication of esophageal rupture is mediastinitis. There are several case reports in the literature of mediastinitis secondary to esophageal perforation and development of aortic pseudoaneurysm as a complication. We report the case of a patient with an 8-day history of esophageal perforation due to foreign body (fishbone) with mediastinitis and aortic pseudoaneurysm. The diagnosis was made using Computed Tomography (CT) with intravenous and oral water-soluble contrast material. An esophagogastroduodenoscopy did not detect the perforation. PMID:26977330

  4. Laparoscopic Management of a Very Rare Case: Cystic Artery Pseudoaneurysm Secondary to Acute Cholecystitis

    PubMed Central

    Ferahman, Sina; Demiryas, Süleyman; Samanci, Cesur

    2016-01-01

    Pseudoaneurysm of a cystic artery is a rare entity that commonly occurs secondary to biliary procedures. Most of the cases in literature are consisted of ruptured aneurysms and to our knowledge, except our case, there were only 3 cases with unruptured aneurysms, which incidentally were detected by radiological methods. When cystic artery pseudoaneurysm is present with acute cholecystitis, most of the reports in literature suggested open cholecystectomy with the ligation of the cystic artery as a main treatment option. In this paper we present a case of acute cholecystitis with unruptured cystic artery pseudoaneurysm that incidentally was detected by computed tomography (CT). Cystic artery pseudoaneurysm was handled laparoscopically with simultaneous cholecystectomy. Due to high risk of rupture, surgeons have evaded laparoscopic approach to acute cholecystitis, which accompanied cystic artery pseudoaneurysm. However herein, we proved that laparoscopic management of cystic artery pseudoaneurysm with simultaneous cholecystectomy is feasible and reliable method. PMID:27635274

  5. Hematemesis Due to a Pseudoaneurysm of the Splenic Artery Secondary to Gastric Tuberculosis

    SciTech Connect

    Kim, Jae Kyu Chung, Seok Kyun; Yoon, Woong; Jeong, Yong Yeon; Kang, Heoung Keun

    2005-05-15

    Gastric tuberculosis (TB) is very rare compared with other sites in the gastrointestinal (GI) tract, and upper GI bleeding is an extremely rare manifestation of gastric TB. Also, a pseudoaneurysm is an uncommon cause of GI bleeding and is often encountered with pancreatitis. To our knowledge, no case of GI bleeding due to a pseudoaneurysm of the splenic artery secondary to gastric TB has been reported previously. We report a patient who presented with hematemesis due to a pseudoaneurysm of the splenic artery secondary to gastric TB.

  6. Endovascular treatment of an infected pseudoaneurysm secondary to retropharyngeal abscess in a child

    PubMed Central

    Diehn, Felix E; Lindsay, Christopher W; Morris, Jonathan M

    2015-01-01

    We describe a rare case of carotid pseudoaneurysm secondary to a retropharyngeal abscess, treated with coil embolization in a 2-year-old boy. The patient presented to an emergency department with symptoms suggesting meningitis but was subsequently diagnosed with streptococcal pharyngitis. He was discharged home on oral antibiotics after a short hospitalization. He returned to the emergency department two weeks later with limited neck motion and pain. Neck CT demonstrated a retropharyngeal abscess with a large left cervical internal carotid artery (ICA) pseudoaneurysm. The petrous ICA distal to the pseudoaneurysm had thrombosed prior to treatment. The ICA proximal to the pseudoaneurysm was sacrificed with coil embolization. Post-treatment imaging demonstrated complete thrombosis of the pseudoaneurysm but also demonstrated acute strokes in the left MCA/ACA watershed distribution. His parents noted that the patient was clumsier and exhibited some mild speech changes and a steppage gait prior to evaluation in the ED; therefore, these were thought to be secondary to emboli from partial thrombosis of the pseudoaneurysm prior to treatment. The patient was discharged home in good condition and his neurological function improved. PMID:26060279

  7. Location of femoral artery puncture site and the risk of postcatheterization pseudoaneurysm formation.

    PubMed

    Gabriel, Marcin; Pawlaczyk, Katarzyna; Waliszewski, Krzysztof; Krasiński, Zbigniew; Majewski, Wacław

    2007-08-21

    Iatrogenic causes constitute increasingly frequent sources of pseudoaneurysms due to endovascular interventions. However, till now, all analyses focused on evaluating different risk factors contributing to the development of pseudoaneurysm, overlooking the issue of localization of femoral puncture. The aim of this study was to assess the influence of position of femoral artery puncture on the risk of pseudoaneurysm formation. 116 patients were evaluated for the site of catheter insertion into femoral arteries. Another group of 273 patients, suspected of vascular complications after endovascular procedures, were diagnosed with pseudoaneurysms which were analyzed for the location of arterial wall disruption. Puncture sites of groin arteries, i.e. EIA (2.7%), CFA (77.5%), SFA and DFA (19.8%), correlated with pseudoaneurysm location reaching 7.6% (EIA), 54.3% (CFA) and 38.1% (SFA, DFA). Type of procedure influenced these values. Duplex ultrasound mapping of CFA before the endovascular intervention eliminated discrepancies between the incidence of pseudoaneurysm formation and the frequency of arterial puncture in the selected vascular segments. Pseudoaneurysms formed in 4.5% of patients undergoing traditional palpation-guided vessel cannulation and in 2.6% of patients after ultrasound-guided puncture of the femoral artery. Upon further analysis, we concluded that the likelihood of the development of pseudoaneurysm depends on the artery punctured in the groin. This risk increases dramatically for external iliac artery, superficial and deep femoral arteries. A simple means of prevention of this dangerous complication of femoral artery puncture is duplex ultrasound mapping of the groin arteries.

  8. [Post-traumatic pseudoaneurysm of the anterior tibial artery secondary to tibial shaft fracture. Case report].

    PubMed

    Gómez-Salazar, J; Tovar-López, J; Hernández-Rodríguez, G; De la Concha-Ureta, H

    2016-01-01

    Arterial pseudoaneurysm of the lower limb is an infrequent entity, particularly in the infrapopliteal segment. It is commonly associated to vascular repairs or follows a localized arterial lesion, a fracture or a surgical procedure. There is little information in Mexico about this entity in cases involving the anterior tibial artery, and secondary to trauma and osteosynthesis. Given that sudden bleeding due to rupture of the pseudoaneurysm is a possible catastrophic outcome for the viability of the segment, it is important to timely detect and diagnose the pseudoaneurysm. Treatment indications contained in the international literature are controversial. Solution-oriented approaches may be either surgical or endovascular. Current reports show that the best treatment option is an autologous saphenous vein graft, which maintains blood flow and minimizes the risk of peripheral ischemia. The purpose of this paper is to report the case of a patient who sustained the above mentioned complication and provide a literature review. This topic should be further investigated, as this condition may go unnoticed in a large number of cases, given that its symptoms are silent.

  9. Compression-refractory breast hematoma secondary to pseudoaneurysm after stereotactically guided vacuum-assisted biopsy: the critical role of urgent surgical evacuation.

    PubMed

    Sun, Simon; Hennessey, Hooman; Kam Nakch, Idris; Alsharif, Shaza; Meterissian, Sarkis; Mesurolle, Benoît

    2014-10-01

    We report the case of a patient who underwent a vacuum-assisted biopsy of amorphous clustered microcalcifications complicated by a large compression-refractory hematoma secondary to pseudoaneurysm formation. Breast sonography was used to identify an actively bleeding vessel and guide compression. However, due to its unresponsiveness to conventional management and rapid progression, the hematoma required surgical evacuation and ligation of the bleeding vessel. This suggests that, in the face of significant intractable bleeding, a heightened awareness of the possible need for surgical intervention should be maintained.

  10. Aortic Pseudoaneurysm Formation Following Concurrent Chemoradiotherapy And Metallic Stent Insertion in a Patient With Esophageal Cancer

    PubMed Central

    Hou, Pei-Yu; Teng, Chung-Jen; Chung, Chen-Shuan; Liu, Chao-Yu; Huang, Chun-Chieh; Chang, Miu-Hsiang; Shueng, Pei-Wei; Hsieh, Chen-Hsi

    2015-01-01

    Abstract Aortic pseudoaneurysm formation subsequent to concurrent chemoradiotherapy (CCRT) for esophageal cancer patient with esophageal metallic stent insertion is a rare condition. A 52-year-old man with esophageal cancer, cT4N1M0, stage IIIC, was treated with concurrent weekly cisplatin (30 mg/m2) and 5-Fluorouracil (500 mg/m2) as well as radiotherapy (50.4 Gy in 28 fractions) for 6 weeks. An esophageal metallic stent was inserted for dysphagia 1 week after initiation of CCRT. During the treatment regimen, the platelet count dropped to less than 200 × 103 /μL. One month after the completion of CCRT, chest CT revealed the presence of an aortic pseudoaneurysm as well as aortoesophageal fistulas. A thoracic aortic endografting was performed and the patient responded well to surgery. However, the patient died 2 months later due to a nosocomial infection. Multimodality treatment for esophageal cancer comprising cisplatin-based CCRT and esophageal metallic stent placement near a great vessel may increase the risk of pseudoaneurysm formation. PMID:25997064

  11. A penetrating nail-prick injury of the lateral plantar artery leading to pseudo-aneurysm formation and rupture.

    PubMed

    Şişli, Emrah; Hasde, Ali İhsan; Mavi, Mustafa; Dursun, Suat

    2014-08-23

    Pseudo-aneurysm in the plantar region is so rare that there are only sporadic case reports in the literature. The aetiology is usually either iatrogenic or stepping on a piece of glass. In comparison to the medial plantar artery, the lateral plantar artery is the most common arterial structure injured in the plantar region due to its more superficial course and it being less protected by the surrounding structures. With variable presentation and different time intervals from injury to diagnosis, the mechanism and penetration depth of the injury is thought to have a major impact on the formation of a pseudo-aneurysm. The aims of this article were to present a case of a lateral plantar artery injury after stepping on a construction nail, leading to pseudo-aneurysm formation and rupture, and to review the literature with regard to the clinical characteristics of these rare and overlooked cases.

  12. Treatment of Secondary Stent-Graft Collapse After Endovascular Stent-Grafting for Iliac Artery Pseudoaneurysms

    SciTech Connect

    Clevert, D.-A. Stickel, M.; Steitz, H.-O.; Kopp, R.; Strautz, T.; Flach, P.; Johnson, T.; Jung, E.M.; Jauch, K.W.; Reiser, M.

    2007-02-15

    We report the case of a patient who developed an asymptomatic pseudoaneurysm in the left external iliac artery after transplant nephrectomy. The pseudoaneurysm most probably arose as a suture aneurysm from the external iliac artery after removal of the graft renal artery. Obviously we can not exclude the possibility it was a true aneurysm, although this seems much less likely. The pseudoaneurysm was detected during a routine CT scan and was treated interventionally with a stent-graft. One month later the asymptomatic patient underwent a vascular ultrasound examination including color Doppler, power Doppler, and B-flow as a routine control. An endoleak with collapse of the stent-graft was diagnosed. There was no evidence of stent infection. At a reintervention, the pseudoaneurysm was successfully treated using two uncovered Palmaz stents at the proximal and distal edge of the stent graft. Peri- and post-interventional ultrasound and CT angiography confirmed the exclusion of the aneurysm without an endoleak.

  13. [A double aorto-enteric fistula secondary to an aortic pseudoaneurysm. Its anatomical correction].

    PubMed

    de Frutos Rincón, J L; Canales Reina, J; Gianpaolo, B; Iglesias Martínez, E; Viñas Salas, J; Casals Garrido, R; Reñé Espinet, J; Pérez Ruiz, L

    1991-01-01

    A very rare case of double fistula aorto-enteric jejunal and ileal, draining to an aortic pseudoaneurysm, is presented. There were not evidence of sepsis, and by this reason pseudoaneurysm and prosthesis were removed, a new prosthesis was inserted by reconstruction "in situ", and intestinal fistulas were closed. The short- and large-term postoperatory was satisfactory. A review about possible mechanisms implicated in a fistula, diagnosis and therapeutic alternatives was made.

  14. Vertebral artery pseudoaneurysms secondary to blunt trauma: Endovascular management by means of neurostents and flow diverters.

    PubMed

    Cohen, José E; Gomori, John M; Rajz, Gustavo; Rosenthal, Guy; El Hassan, Hosni Abu; Moscovici, Samuel; Itshayek, Eyal

    2016-10-01

    Extracranial vertebral pseudoaneurysms that develop following blunt trauma to the cervical area may have a benign course; however, embolic or ischemic stroke and progressive pseudoaneurysm enlargement may occur. We review the presentation and endovascular management of pseudoaneurysms of the cervical vertebral artery (VA) due to blunt trauma in nine patients (eight male, mean age 27years). Pseudoaneurysms occurred in dominant vessels in seven patients and coexisted with segmental narrowing in six. We favored endovascular intervention during the acute phase only in cases with significant narrowing of a dominant VA, especially when anticoagulation was contraindicated. Four patients were treated during the acute stage (contraindication to anticoagulation, mass effect, severely injured dominant VA/impending stroke); five during the chronic phase (pseudoaneurysm growth, ischemic stroke on aspirin prophylaxis, patient preference). Reconstructive techniques were favored over deliberate endovascular occlusion when dominant vessels were involved. Arterial reconstruction was performed in eight of nine patients using a flow-diverter implant (5 patients), stent-assisted coiling (1), overlapping stent implant (1), or implantation of a balloon-expandable stent (1). Deliberate VA occlusion with coils was performed in one of nine patients due to suboptimal expansion of the stented artery after flow-diverter implant. No neurological complications occurred during follow-up. All cases treated by reconstructive techniques showed complete, persistent pseudoaneurysm occlusion and full arterial patency. Endovascular therapy of traumatic VA pseudoaneurysms using neurostents and flow-diverters resulted in occlusion of the pseudoaneurysms, preservation of the parent vessel, and no periprocedural or delayed clinical complications, supporting the feasibility and safety of the approach.

  15. A New Flow Control Technique Using Diluted Epinephrine in the N-butyl-2-cyanoacrylate Embolization of Visceral Artery Pseudoaneurysms Secondary to Chronic Pancreatitis

    SciTech Connect

    Morishita, Hiroyuki; Yamagami, Takuji; Takeuchi, Yoshito; Matsumoto, Tomohiro; Asai, Shunsuke; Masui, Koji; Sato, Hideki; Taniguchi, Fumihiro; Sato, Osamu; Nishimura, Tsunehiko

    2012-08-15

    Although n-butyl-2-cyanoacrylate (NBCA) has been used as an effective liquid embolization material, its indication for pseudoaneurysms has seemingly been limited because of the technical difficulties of using NBCA, such as reflux to the parent artery and causing significant infarction. Thus, considerable skill in using NBCA or a device to control blood flow during its polymerization is required to achieve embolization without severe complications. We report our new technique for controlling blood flow using diluted epinephrine in transcatheter arterial NBCA embolization of five pseudoaneurysms in four cases secondary to hemosuccus pancreaticus.

  16. Endovascular Treatment of a Brachiocephalic Artery Pseudoaneurysm Secondary to Biopsy at Mediastinoscopy

    SciTech Connect

    Ahmed, Irfan Katsanos, Konstantinos; Ahmad, Farhan; Dourado, Renato; Lyons, Oliver; Reidy, John

    2009-07-15

    Isolated injury to the brachiocephalic artery is relatively rare. We report the case of a 53-year-old lymphoma patient who had had a biopsy at mediastinoscopy in the past and was found incidentally on routine staging computed tomography to have developed a large pseudoaneurysm of the brachiocephalic artery. We describe the successful percutaneous treatment of this iatrogenic injury using endovascular deployment of covered stent-grafts.

  17. Spontaneous left main coronary artery dissection complicated by pseudoaneurysm formation in pregnancy: role of CT coronary angiography.

    PubMed

    Rahman, Shahid; Abdul-Waheed, Mohammed; Helmy, Tarek; Huffman, Lynn C; Koshal, Vipin; Guitron, Julian; Merrill, Walter H; Lewis, David F; Dunlap, Stephanie; Shizukuda, Yukitaka; Weintraub, Neal L; Meyer, Christopher; Cilingiroglu, Mehmet

    2009-04-01

    We report a case of a 26-year-old female, who presented at 34 weeks of an uncomplicated pregnancy with an acute ST elevation anterior wall myocardial infarction. Cardiac catheterization suggested a left main coronary artery dissection with pseudoaneurysm formation. The patient's course was complicated by congestive heart failure. She was initially managed conservatively by a multidisciplinary team including heart failure specialists, obstetricians, and cardiovascular surgeons. 4 days after admission, her LMC was imaged by dual-source 64 slice Cardiac computed tomography, coronary dissection was identified extending to the lumen, and the presence of pseudoaneurysm was confirmed. She underwent subsequently a staged procedure, which included placement of an intra-aortic balloon pump, cesarean section, and coronary artery bypass grafting. This case illustrates the utility of coronary artery CT imaging to assess the complexity and stability of coronary artery dissections, thereby helping to determine the need for, and timing of revascularization procedures.

  18. Totally Endovascular Management of Popliteal Artery Occlusion and Pseudoaneurysm Formation after Total Knee Replacement.

    PubMed

    Reynolds, Anthony; Sandstrom, Anna; Jha, Pankaj K

    2017-01-01

    Injuries to the popliteal artery during total knee arthroplasty (TKA) are rare. We present a case of a 72-year-old man with popliteal artery thrombosis and a pseudoaneurysm presenting immediately after TKA. First-line management of acute limb ischemia is currently transitioning from open surgery to endovascular strategies such as catheter-directed thrombolysis or mechanical thrombectomy. Due to the rarity of acute limb ischemia and pseudoaneurysms after TKA, endovascular management is only reported in a few case studies. This case is distinctive by having both popliteal artery thrombosis and a pseudoaneurysm which were successfully managed entirely endovascular using AngioJet thrombolysis and a flexible covered stent. This case contributes to the evidence supporting endovascular management of this rare complication of TKA.

  19. Characteristics of Pseudoaneurysms in Northern India; Risk Analysis, Clinical Profile, Surgical Management and Outcome

    PubMed Central

    Lone, Hafeezulla; Ganaie, Farooq Ahmad; Lone, Ghulam Nabi; Dar, Abdul Majeed; Bhat, Mohammad Akbar; Singh, Shyam; Parra, Khursheed Ahmad

    2015-01-01

    Objective: To determine the risk factors, clinical characteristics, surgical management and outcome of pseudoaneurysm secondary to iatrogenic or traumatic vascular injury. Methods: This was a cross-sectional study being performed in department of cardiovascular and thoracic surgery skims soura during a 4-year period. We included all the patients referring to our center with primary diagnosis of pseudoaneurysm. The pseudoaneurysm was diagnosed with angiography and color Doppler sonography. The clinical and demographic characteristics were recorded and the risk factors were identified accordingly. Patients with small swelling (less than 5-cm) and without any complication were managed conservatively. They were followed for progression and development of complications in relation to swelling. Others underwent surgical repair and excision. The outcome of the patients was also recorded. Results: Overall we included 20 patients with pseudoaneurysm. The mean age of the patients was 42.1±0.6 years. Among them there were 11 (55%) men and 9 (45%) women. Nine (45%) patients with end stage renal disease developed pseudoaneurysm after inadvertent femoral artery puncture for hemodialysis; two patients after interventional cardiology procedure; one after femoral embolectomy; one developed after fire arm splinter injury and one formed femoral artery related pseudoaneurysm after drainage of right inguinal abscess. The most common site of pseudoaneurysm was femoral artery followed by brachial artery. Overall surgical intervention was performed in 17 (85%) patients and 3 (15%) were managed conservatively. Conclusion: End stage renal disease is a major risk factor for pseudoaneurysm formation. Coagulopathy, either therapeutic or pathological is also an important risk factor. Patients with these risk factors need cannulation of venous structures for hemodialysis under ultrasound guide to prevent inadvertent arterial injury. Patients with end stage renal disease who sustain inadvertent

  20. A rare case of iatrogenic pseudoaneurysm of the left brachiocephalic vein after central venous catheterization treated with thrombin injection.

    PubMed

    Elsaadany, Amr Maged; Alaeddin, Fida Hasan; Alsuhaibani, Hamad Abdulla

    2014-08-01

    Rupture of the central veins with venous pseudoaneurysm formation is an unusual complication of central venous catheterization. Only seven cases of brachiocephalic venous pseudoaneurysm have been reported in the literature (among these only one was secondary to central venous catheterization). Plain radiographic examination of the chest may show widening of the mediastinum, pleural effusion (haemothorax), and/or opacity overlying the hemithorax of the injured vein. Further evaluation using either computed tomography or magnetic resonance imaging can be performed. Venography is considered an important tool, especially when an intervention is planned. We present the first reported case of brachiocephalic vein pseudoaneurysm treated solely with thrombin injection. The imaging, other treatment options, and literature review of brachiocephalic venous pseudoaneurysm are also discussed.

  1. Pseudoaneurysm Formation After Medtronic Freestyle Porcine Aortic Bioprosthesis Implantation: A Word of Caution

    PubMed Central

    Englum, Brian R.; Pavlisko, Elizabeth N.; Mack, Molly C.; Ganapathi, Asvin M.; Schechter, Matthew A.; Hanna, Jennifer M.; Hughes, G. Chad

    2015-01-01

    Background A growing literature describes aneurysmal deterioration after implantation of the stentless porcine aortic Medtronic Freestyle bioprosthesis (MFB; Medtronic Inc, Minneapolis, MN), with some suggesting inadequate tissue fixation with immune response as a cause. However, disjointed reports make the significance of these findings difficult to interpret. We address this concern by aggregating available data. Methods We reviewed institutional data, the Food and Drug Administration’s Manufacturer and User Facility Device Experience registry, and the medical literature for mention of aneurysm or pseudoaneurysm after MFB. Case details were aggregated, and the rate of aneurysmal deterioration was estimated. Immunohistopathologic examination of institutional explanted specimens was performed to elucidate a cause. Results We found 42 cases of aneurysmal deterioration with adequate detail for analysis; all occurred with full root replacement and valve sizes ranging from 23 to 29 mm. The rate of aneurysmal deterioration considering all data sources was 1.1% (9 of 851; 95% confidence interval, 0.5% to 2.0%) vs 4.7% (4 of 86; 95% confidence interval, 1.3% to 11.5%) at our institution, where yearly surveillance imaging is performed. Rate of aneurysmal deterioration appeared constant until 5 years after the operation; however, events are reported out to 10 years. Consistent with previous reports, histopathology demonstrated an immune cell infiltrate in areas of MFB wall breakdown. Conclusions Aneurysmal deterioration is an increasingly described complication of MFB implantation as a full root, with an incidence as high as 4.7%. Given the observed immune reaction and lack of occurrence in smaller (19-mm and 21-mm) valve sizes, inadequate pressure fixation of larger valves is a potential etiology. Patients with MFB require annual surveillance imaging, and consideration of this complication should factor into preoperative decision making because treatment mandates redo

  2. Diagnosis of gynecological pseudoaneurysms and embolization with cyanoacrylate.

    PubMed

    Fernández Bermúdez, M J; Fernández Martínez, A M; Domitrovic, L A; Balboa Arregui, Ó

    2016-12-21

    Pseudoaneurysms of the uterine artery are an uncommon cause of severe gynecological bleeding secondary to surgical manipulation of the pelvis or to instrumental delivery. The different imaging techniques are of vital importance in the diagnosis. Angiography is the technique used for confirmation and also for treatment in many cases. Endovascular treatment by embolizing the pseudoaneurysm has become established as the treatment of choice, making it possible to avoid hysterectomy in women of childbearing age. This article presents two cases of gynecological bleeding due to pseudoaneurysms (one secondary to surgery and one secondary to childbirth) that were embolized in a novel way using cyanoacrylate.

  3. [Pancreatic tail pseudoaneurysm: percutaneous treatment by thrombin injection].

    PubMed

    Pacheco Jiménez, M; Moreno Sánchez, T; Moreno Rodríguez, F; Guillén Rico, M

    2014-01-01

    Visceral artery pseudoaneurysms secondary to acute and/or chronic pancreatitis are a relatively common and potentially serious complication. Endovascular techniques are the most currently accepted techniques, given the higher morbidity-mortality of surgery. The thrombosis of the pseudoaneurysm using an ultrasound-guided percutaneous thrombin injection is emerging as a useful option in those cases in which endovascular embolisation is not possible. We present the case of a patient with a pseudoaneurysm of the transverse pancreatic artery secondary to chronic pancreatitis, and successfully treated by administering percutaneous thrombin.

  4. Endovascular management of postoperative pseudoaneurysms of the external carotid artery.

    PubMed

    Cohen, José E; Gomori, John M; Moscovici, Samuel; Grigoriadis, Savvas; Ramirez de Noriega, Fernando; Itshayek, Eyal

    2012-05-01

    Hemorrhage secondary to postoperative pseudoaneurysm is a rare event, but may complicate the clinical course of straightforward and common interventions such as sinonasal procedures, tonsillectomy, and maxillofacial and plastic surgeries. We report our experience with the endovascular management of iatrogenic pseudoaneurysm in eight patients who had undergone recent craniomaxillofacial surgery. Computed tomography (CT), including CT-angiography, detected only three of the eight lesions. In all patients, endovascular embolization achieved successful occlusion of the pseudoaneurysm without local or general procedure-related complications. Immediate proximal arterial occlusion with detachable coils was performed in every case, and pseudoaneurysm coiling was performed in three cases presenting with active hemorrhage. Endovascular therapy proved to be safe and effective in the management of postoperative pseudoaneurysms. Surgeons involved in the craniomaxillofacial procedures should be aware of this complication and its management.

  5. [Coombs-negative autoimmune hemolytic anemia developed after formation of post-operative pseudoaneurysm for femoral neck fracture].

    PubMed

    Hagihara, Masao; Hua, Jian; Inoue, Morihiro; Michikawa, Naohiko

    2011-03-01

    An 85-year-old woman was admitted to our hospital with severe anemia after nail-plate fixation of the left femoral neck fracture. The patient was diagnosed with Coombs-negative autoimmune hemolytic anemia based on the measurement of red blood cell (RBC)-bound IgG molecules per cell. Pseudoaneurysm of the left profunda femoris artery was detected on magnetic resonance imaging and successfully removed by surgical repair of the artery. Anemia promptly improved, and the number of RBC-bound IgG normalized after the surgery. The destruction of RBCs was thought to have been responsible for temporary induction of anti-RBC autoimmune antibodies.

  6. Life-threatening Rupture of a Femoral Pseudoaneurysm after Cardiac Catheterization

    PubMed Central

    Petrou, Emmanouil; Malakos, Ioannis; Kampanarou, Stamatina; Doulas, Nikolaos; Voudris, Vassilis

    2016-01-01

    A pseudoaneurysm refers to a defect in the arterial wall, allowing communication of arterial blood with the adjacent extra-luminal space. Pseudoaneurysms result from traumatic arterial injury. With the increasing utilization of percutaneous arterial interventions, iatrogenic arterial injury has become the predominant cause of pseudoaneurysm formation. Rupture of the pseudoaneurysm comprises a vascular emergency. Clinical suspicion and imaging techniques are the cornerstones of timely diagnosis and appropriate management of the condition. Herein, we report the case of a 69 year-old woman who suffered a life-threatening profunda femoral artery pseudoaneurysm rupture after a routine cardiac catheterization, that was treated surgically. PMID:27733869

  7. [Chronic Heart Failure Due to Formation of Giant Left Ventricular Pseudoaneurysm After Painless Myocardial Infarction in a Female Patient With Diabetes].

    PubMed

    Katkova, L A; Furman, N V; Dolotovskaya, P V; Dovgalevsky, Ya P; Sakharova, N K; Panteleeva, E A; Parshina, E A

    2016-09-01

    Rupture of the free wall of the left ventricle with the formation of a false aneurysm (pseudoaneurysm, PA) - is a rare complication of acute myocardial infarction. Given the high risk of rupture of the PA and other life-threatening consequences (progressive heart failure, thromboembolic events), as well as the absence of pathognomonic signs and the difficulty in determining treatment strategy (feasibility and timing of surgery), early diagnosis of this complication appears to be especially important. We present here an overview of literature data on prevalence, specific features of diagnostics, and problems related to selection of method of treatment of PA. A case f congestive heart failure due to PA of the left ventricle as a result of painless myocardial infarction in 65-year-old patient with diabetes is also presented.

  8. Secondary organic aerosol formation of primary, secondary and tertiary Amines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amines have been widely identified in ambient aerosol in both urban and rural environments and they are potential precursors for formation of nitrogen-containing secondary organic aerosols (SOA). However, the role of amines in SOA formation has not been well studied. In this wrok, we use UC-Riversid...

  9. Superior Mesenteric Artery Pseudoaneurysm Following Pancreaticoduodenectomy: Management by Endovascular Stent-Graft Placement and Transluminal Thrombin Injection

    SciTech Connect

    Wallace, Michael J. Choi, Eugene; McRae, Stephen; Madoff, David C.; Ahrar, Kamran; Pisters, Peter

    2007-06-15

    Superior mesenteric artery (SMA) pseudoaneurysm formation is a rare and potentially fatal postoperative complication. Herein we present a case of a large post-pancreaticoduodenectomy SMA pseudoaneurysm that required thrombin injection after initial stent-graft deployment to accomplish complete pseudoaneurysm occlusion.

  10. Processes and problems in secondary star formation

    SciTech Connect

    Klein, R.I.; Whitaker, R.W.; Sandford M.T. II

    1984-03-01

    Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of the observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on colliding inter-cloud gas flows leading to non-linear inhomogeneous cloud structures in an intially smooth cloud. This clumpy morphology has important consequences for secondary formation. The triggering processes of supernovae, stellar winds, and H II regions are discussed with emphasis on the consequences for radiation driven implosion as a promising secondary star formation mechanism. Detailed two-dimensional, radiation-hydrodynamic calculations of radiation driven implosion are discussed. This mechanism is shown to be highly efficient in synchronizing the formation of new stars in congruent to 1-3 x 10/sup 4/ years and could account for the recent evidence for new massive star formation in several UCHII regions. It is concluded that, while no single theory adequately explains the variety of star formation observed, a uniform description of star formation is likely to involve several secondary processes. Advances in the theory of star formation will require multiple dimensional calculations of coupled processes. The important non-linear interactions include hydrodynamics, radiation transport, and magnetic fields.

  11. Tamponade by an expanding left ventricular pseudoaneurysm: A unique presentation.

    PubMed

    Mahesh, Balakrishnan; Ong, Ping; Kutty, Ramesh; Abu-Omar, Yasir

    2015-10-01

    Left ventricular free wall rupture secondary to myocardial infarction is an uncommon but catastrophic event requiring emergency surgery. We describe a unique presentation of left ventricular free wall rupture as delayed tamponade caused by a gradually expanding pseudoaneurysm compressing the left atrium, leading to pulmonary congestion that required increasing respiratory support to maintain oxygenation, and necessitated emergency surgery. We discuss the options available to treat pseudoaneurysms due to left ventricular free wall rupture.

  12. Cardiac catheterization: What causes a pseudoaneurysm? Should a pseudoaneurysm always be treated?

    MedlinePlus

    Pseudoaneurysm: What causes it? What causes a pseudoaneurysm? Should a pseudoaneurysm always be treated? Answers from Rekha Mankad, M.D. A pseudoaneurysm, sometimes called a false aneurysm, occurs when ...

  13. Nontraumatic Rupture of Lumbar Artery Causing an Intravertebral Body Pseudoaneurysm: Treatment by Transcatheter Embolization

    SciTech Connect

    Shigematsu, Yoshinori Kudoh, Kouichi; Nakasone, Yutaka; Fujisaki, Tadashi; Uemura, Shouichirou; Yamashita, Yasuyuki

    2006-10-15

    We report a case of nontraumatic rupture of the lumbar artery that led to a pseudoaneurysm in the vertebral body and massive retroperitoneal to retropleural hematoma. The pseudoaneurysm was successfully treated by endovascular embolization. To our knowledge, idiopathic rupture of the lumbar artery has been reported in a limited number of cases and pseudoaneurysm formation in the vertebral body has not been presented in the literature. The etiology of hemorrhage has been discussed based on CT, MRI, and three-dimensional rotational angiography.

  14. Non-pulsatile traumatic pseudoaneurysm of the internal maxillary artery following trauma to mandible.

    PubMed

    Soh, Hui Yuh; Muda, Ahmad Sobri; Jabar, Nazimi Abd; Nordin, Rifqah; Nabil, S; Ramli, Roszalina

    2015-12-01

    Traumatic pseudoaneurysm involving the maxillary artery is rare. Owing to its anatomic location, internal maxillary artery is usually protected by its surrounding structures. Formation of pseudoaneurysm usually takes place after several weeks to months of the initial injury. In this case, we reported a pseudoaneurysm arising from left internal maxillary artery following blunt injuries within 3 hours after a road accident and the treatment with endovascular embolization with titanium coils prior to open reduction and internal fixation of the fractured mandibles.

  15. Percutaneous Ultrasound-Guided Thrombin Injection as First-Line Treatment of Pancreatic Pseudoaneurysm

    SciTech Connect

    McErlean, Aoife; Looby, Seamus; Lee, Michael J.

    2007-06-15

    Pancreatic pseudoaneurysms are a rare but potentially fatal complication of pancreatitis. Surgical intervention and transcatheter embolization are not always feasible therapeutic options. In this report we present a case of a pseudoaneurysm secondary to pancreatitis which, despite being angiographically invisible, was successfully embolized with a single ultrasound-guided percutaneous injection of thrombin.

  16. Organosulfate Formation in Biogenic Secondary Organic Aerosol

    EPA Science Inventory

    Organosulfates of isoprene, α-pinene, and β-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive seri...

  17. Pseudoaneurysm after arthroscopic procedure in the knee.

    PubMed

    Filho, Edmar Stieven; Isolani, Guilherme Rufini; Baracho, Filipe Ribas; de Oliveira Franco, Ana Paula Gebert; Ridder Bauer, Luiz Antônio; Namba, Mario

    2015-01-01

    The aim of this study was to review all cases of pseudoaneurysm in the literature, in predominantly arthroscopic procedures on the knee, and to report on a case of pseudoaneurysm that we treated. A bibliographic search was conducted for scientific articles published in Brazilian and foreign periodicals over the last 23 years. Forty-seven cases were found, in 40 articles. In addition to these 47 cases, there was the case that we treated, which was also included in the data. Among the operations that progressed with formation of a pseudoaneurysm, 60% were cases of meniscal injuries and 23%, anterior cruciate ligament injuries. In 46% of the cases, the artery affected with the popliteal, and in 21%, the inferomedial genicular artery. The commonest clinical symptom was pain (37%), followed by pulsating tumor (31%), edema of the calf (12%) and hemarthrosis (11%). The median time taken to make the diagnosis was 11 days, but it ranged from one day to 10 weeks after the procedure. Although rare, pseudoaneurysms are a risk that is inherent to arthroscopic surgery. All patients should be made aware of the vascular risks, even in small-scale procedures.

  18. Percutaneous Stent-Graft Repair of Anastomotic Pseudoaneurysms following Vascular Bypass Procedures: A Report of Two Cases

    PubMed Central

    Rundback, John; Haug, James; Herman, Kevin; Manno, Joseph; Cerda, Martin

    2013-01-01

    Anastomotic pseudoaneurysms are common entities following vascular bypass procedures and, if left untreated, serious complications such as thromboses, infection, and rupture can frequently occur. Therefore, attempts to employ various methods of repair have been utilized in treating anastomotic pseudoaneurysms to maximize operational success and future risk reduction. Herein, the authors report two cases of anastomotic pseudoaneurysms which were repaired percutaneously utilizing a combination of strategies such as careful preoperational image planning, multiple commercially available devices, and secondary embolization techniques. PMID:23365781

  19. Ultrasound-guided trans-hepatic embolization of a renal artery pseudoaneurysm in a patient with acquired solitary kidney and with chronic renal failure secondary to phenacetin abuse.

    PubMed

    Ferramosca, Emiliana; Serra, Carla; Di Felice, Antonio; Mandreoli, Marcora; Brunocilla, Eugenio; Santoro, Antonio

    2014-03-01

    A patient with a pseudoaneurysm of the right renal artery underwent treatment with percutaneous approach. No complications were observed. Based on the experience described in this report, a percutaneous ultrasound guided approach can be proposed in selected patients. Renal insufficiency and allergic reactions are potential contraindications to angiography with conventional ionic iodinated contrast dye in patients who need endovascular stent-graft placement. Real-time contrast-enhanced ultrasound (CEUS) guided endovascular procedures may provide an alternative to overcome these limitations. We report an endovascular renal artery repair in a solitary kidney patient with an asymptomatic infrarenal aortic aneurysm and renal insufficiency due to phenacetin abuse. The precise placement of the stent-graft was performed with CEUS and intraprocedural angiographic fluoroscopy without the use of any nephrotoxic contrast dye. During follow-up, CEUS was used to exclude endoleaks, stent-graft failure or malposition.

  20. Pseudoaneurysm of the aortic arch

    PubMed Central

    Lu, Yuan-Qiang; Yao, Feng; Shang, An-Dong; Pan, Jian

    2016-01-01

    Abstract Background: Pseudoaneurysm of the aortic arch is uncommonly associated with cancer, and is extremely rare in pulmonary cancer. Here, we report an unusual and successfully treated case of aortic arch pseudoaneurysm in a male patient with lung squamous cell carcinoma. Methods: A 64-year-old male patient was admitted to the Emergency Department, presenting with massive hemoptysis (>500 mL blood during the 12 hours prior to treatment). The diagnosis of aortic arch pseudoaneurysm was confirmed after inspection of computed tomographic angiography and three-dimensional reconstruction. We processed the immediate endovascular stent-grafting for this patient. Results: This patient recovered with no filling or enlargement of the pseudoaneurysm, no episodes of hemoptysis, and no neurological complications during the 4-week follow-up period. Conclusion: Herein, we compare our case with other cancer-related pseudoaneurysms in the medical literature and summarize the clinical features and treatment of this unusual case. PMID:27495079

  1. Rare presentation of ruptured syphilitic aortic aneurysm with pseudoaneurysm.

    PubMed

    de Almeida Feitosa, Israel Nilton; Dantas Leite Figueiredo, Magda; de Sousa Belem, Lucia; Evelin Soares Filho, Antônio Wilon

    2015-11-01

    We report the interesting case of a rare form of presentation of rupture of the ascending aorta with formation of a pseudoaneurysm, diagnosed following the development of a large mass on the surface of the chest over a period of about eight months. Serological tests were positive for syphilis. Echocardiography and computed tomography angiography were essential to confirm the diagnosis and therapeutic management. Cardiovascular syphilis is a rare entity since the discovery of penicillin. Rupture of an aortic aneurysm with formation of a pseudoaneurysm is a potentially fatal complication. The postoperative period was uneventful and the patient was discharged from hospital within days of surgery.

  2. Subclavian Artery Occlusion and Pseudoaneurysm Caused by Lung Apex Mucormycosis: Successful Treatment with Transcatheter Embolization

    SciTech Connect

    Economopoulos, Nikolaos; Kelekis, Dimitris; Papadopoulos, Antonios; Kontopoulou, Christina; Brountzos, Elias N.

    2007-02-15

    Subclavian artery pseudoaneurysm and occlusion in young patients are usually post-traumatic. We report the case of a 33-year-old diabetic woman with subclavian artery occlusion and pseudoaneurysm formation caused by pulmonary mucormycosis infection. The patient presented with diabetic ketoacidosis, Horner's syndrome, and absent left arm pulses. A cystic lesion of the left lung apex was found by imaging, was surgically resected, and was histologically diagnosed as mucormycosis infection. Magnetic resonance angiography depicted a left subclavian artery pseudoaneurysm and occlusion adjacent to the mucormycosis lesion. To protect against thromboembolic complications and rupture, the pseudoaneurysm was embolized with coils. The patient is clinically well 1 year after the intervention with no perfusion of the pseudoaneurysm.

  3. Giant left ventricular pseudoaneurysm.

    PubMed

    Prakash, Sumi; Garg, Nadish; Xie, Gong-Yuan; Dellsperger, Kevin C

    2010-01-01

    Left ventricular (LV) pseudoaneurysm (PS) is an uncommon, often fatal complication associated with myocardial infarction, cardiothoracic surgery, trauma, and, rarely, infective endocarditis. A 28-year-old man with prior history of bioprosthetic mitral valve replacement presented with congestive heart failure and bacteremia with Abiotrophia granulitica. Transesophageal echocardiogram showed bioprosthesis dysfunction, large vegetations, mitral regurgitation, and probable PS. Cardiac and chest CT confirmed a PS communicating with the left ventricle Patient had pulseless electrical activity and died. Autopsy showed a giant PS with layered thrombus and pseudo-endothelialized cavity. Our case highlights the importance of multimodality imaging as an important tool in management of PS.

  4. Diagnosis and management of pseudoaneurysms.

    PubMed

    Mansour, M Ashraf; Gorsuch, Jill M

    2007-03-01

    Pseudoaneurysms develop at the site of arterial access when there is failure to establish adequate hemostasis. The number of percutaneous diagnostic and therapeutic coronary and peripheral vascular interventions has increased and with it a commensurate rise in the incidence of pseudoaneurysms is observed. Clinical examination and color-flow duplex ultrasound identify the majority of pseudoaneurysms. Ultrasound-guided thrombin injection has been shown to be the ideal method to treat the vast majority of false aneurysms. In a small number of cases, alternative endovascular techniques or open surgical repair is required.

  5. Organosulfate formation in biogenic secondary organic aerosol.

    PubMed

    Surratt, Jason D; Gómez-González, Yadian; Chan, Arthur W H; Vermeylen, Reinhilde; Shahgholi, Mona; Kleindienst, Tadeusz E; Edney, Edward O; Offenberg, John H; Lewandowski, Michael; Jaoui, Mohammed; Maenhaut, Willy; Claeys, Magda; Flagan, Richard C; Seinfeld, John H

    2008-09-11

    Organosulfates of isoprene, alpha-pinene, and beta-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO3-initiated oxidation under dark conditions) experiments using nine monoterpenes (alpha-pinene, beta-pinene, d-limonene, l-limonene, alpha-terpinene, gamma-terpinene, terpinolene, Delta(3)-carene, and beta-phellandrene) and three monoterpenes (alpha-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, alpha-pinene, beta-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate

  6. Percutaneous thrombin embolization of a pancreatico-duodenal artery pseudoaneurysm after failing of the endovascular treatment

    PubMed Central

    Barbiero, Giulio; Battistel, Michele; Susac, Ana; Miotto, Diego

    2014-01-01

    Pancreatico-duodenal artery (PDA) pseudoaneurysms are rare vascular conditions with high mortality rates after rupture and they are frequently secondary to pancreatitis, surgery, trauma or infection. Due to the high risk of rupture and bleeding, it is mandatory to treat all pseudoaneurysms, regardless of their size or symptomatology. First option of treatment is open surgical repair, but it has high mortality rate, especially in hemodynamically unstable patients. In the recent years, percutaneous ultrasonography (US)- or computed tomography-guided thrombin injection was proposed as an alternative method for treating visceral aneurysms and pseudoaneurysms, but few reports described this therapy in case of peri-pancreatic pseudoaneurysms. We present a rare case of pseudoaneurysm of the PDA in a patient with no previous history of pancreatitis nor major surgery but with an occlusive lesion of the celiac axis. To the best of our knowledge this is the first reported case of PDA pseudoaneurysm successfully treated in emergency by single transabdominal US-guided injection of thrombin after failed attempts of percutaneous catheterization of the feeding vessel of the pseudoaneurysm. PMID:25170402

  7. Early Diagnosis of Intrahepatic Pseudoaneurysm during Radiofrequency Ablation using Contrast-Enhanced Ultrasound

    PubMed Central

    Kumar, S Krishna; Oon, Ong Keh; Horgan, Paul; Leen, Edward

    2015-01-01

    Radiofrequency ablation is one of the more established forms of local treatment in patients with unresectable tumours, including colorectal hepatic metastases. Complications associated with this method of intervention include thermal and mechanical injuries, including vascular insults resulting in haemorrhage or pseudoaneurysm formation. This is the first case demonstrating the detection of post-ablation acute pseudoaneurysm formation identified on the table using contrast-enhanced ultrasound (CEUS) and the subsequent successful management. PMID:28223887

  8. Recent Studies Investigating Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Weber, R. J.

    2009-05-01

    The metropolitan areas of Mexico City and Atlanta have very different emissions and meteorology, yet in both cities secondary organic aerosol (SOA) comprises a significant fraction of fine particle mass. SOA in Mexico City is predominately from anthropogenic emissions and a number of studies have investigated the role of dicarbonyl partitioning to aerosol liquid water as a SOA formation route [Volkamer et al., 2006; 2007]. Hennigan et al. [2008] noted a high correlation between SOA (measured as water-soluble organic carbon) and fine particle nitrate in Mexico City and used this to estimate the volatility of both species during periods of rapidly decreasing RH in late morning. Secondary aerosol may also form when particles are much drier. In Mexico City, both nitrate and SOA were also frequently observed and highly correlated in late afternoon when RH was below 30 percent. A thermodynamic model could reproduce the observed morning nitrate under high RH when equilibrium was between nitric acid and dissolved nitrate, whereas equilibrium between vapor and crystalline ammonium nitrate was predicted in the afternoon [Fountoukis et al., 2007]. By analogy, these results may suggest two different SOA partitioning mechanisms in Mexico City, occurring at different times of the day. In contrast, measurements suggest that SOA in the southeastern United States is largely from biogenic precursors, and there is evidence that liquid water also plays a role. The stability of dissolved organic aerosol in response to loss of liquid water is currently being investigated and preliminary data suggest that like Mexico City, there is some degree of volatility. Recent experiments comparing data from rural-urban sites shows that there are periods when anthropogenic emissions also substantially contribute to SOA in the Atlanta metropolitan region. However, the mechanisms, or organic precursors involved, are yet to be determined. Results from these various ongoing studies will be presented

  9. Characterizing the formation of secondary organic aerosols

    SciTech Connect

    Lunden, Melissa; Black, Douglas; Brown, Nancy

    2004-02-01

    combination of the aerosol and gas phase data, will continue to provide important information on the extent to which biogenic emissions contribute to secondary organic aerosol and may elucidate important interactions between anthropogenic and biogenic sources. The results of these studies, performed in the field, will contribute to the growing effort to produce robust models for particulate formation that are necessary for air quality planning and source apportionment.

  10. Cardiac Pseudoaneurysm- A Death Defying Entity

    PubMed Central

    Gupta, Saryu

    2016-01-01

    A pseudoaneurysm refers to a contained rupture of the myocardium with a tenuous pericardium walling off the leak. It needs to be differentiated from a true aneurysm by the fact that there is lack of myocardial tissue in the wall of a pseudoaneurysm. The differentiation between the two is pertinent as true aneurysms can be treated medically while pseudoaneurysms require urgent surgical treatment. Untreated pseudoaneurysms carry a high risk of rupture and mortality. We report a case of cardiac pseudoaneurysm developing in a 46-year-old male who had suffered myocardial infarction four months back. The patient now presented with chest pain and dyspnoea. CECT chest revealed a partially thrombosed large pseudoaneurysm arising from the posterior wall of left ventricle. While the clinical diagnosis of this entity is difficult, CECT plays a pivotal role in the non-invasive detection of pseudoaneurysms. PMID:27504379

  11. Formation of secondary radiation fields at NICA

    NASA Astrophysics Data System (ADS)

    Timoshenko, G.; Paraipan, M.

    2009-09-01

    The crucial points of a radiation shielding design for a relativistic heavy ion accelerator are the source term problem, neutron fluence and dose attenuation characteristics of the shielding. Simulations of the radiation shielding for JINR's Nuclotron-Based Ion Facility (NICA) project were carried out using the GEANT4 code. Some regularities in the secondary neutron field generation at the 4.5 GeV/n uranium beam interaction with thick targets are discussed. Neutron attenuation by the ordinary concrete shielding of NICA was considered as well.

  12. Three-dimensional computed tomography angiography for the investigation of superficial temporal artery pseudoaneurysms--two case reports--.

    PubMed

    Higashino, Takuya; Kawashima, Masatou; Mannoji, Hiromichi

    2005-03-01

    An 89-year-old man and a 60-year-old man presented with superficial temporal artery (STA) pseudoaneurysms which developed secondary to trauma. Conventional cerebral angiography and three-dimensional computed tomography (3D CT) angiography clearly demonstrated the STA pseudoaneurysms. The patients underwent surgical excision of the aneurysms based on the conventional cerebral angiography findings in one patient and 3D CT angiography findings in other patient. 3D CT angiography is an excellent noninvasive diagnostic method for detecting extracranial aneurysms such as STA pseudoaneurysm, especially the relationship between the aneurysm and surrounding structures, including the calvarium.

  13. Interventional Radiology in the Diagnosis, Management, and Follow-Up of Pseudoaneurysms

    SciTech Connect

    Keeling, A. N.; McGrath, F. P.; Lee, M. J.

    2009-01-15

    Arterial wall disruption, as a consequence of inflammation/infection, trauma (penetrating or blunt), or iatrogenic causes, may result in pseudoaneurysm formation. Currently, iatrogenic causes are increasing as a result of the growth of endovascular intervention. The frequency of other causes also seems to be increasing, but this may simply be the result of increased diagnosis by better imaging techniques, such as multidetector contrast-enhanced computed tomography. Clinically, pseudoaneurysms may be silent, may present with local or systemic signs, or can rupture with catastrophic consequences. Open surgical repair, previously the mainstay of treatment, has largely been replaced by image-guided occlusion methods. On the basis of an experience of over 100 pseudoaneurysms, treatments at various anatomical sites, imaging modalities used for accurate diagnosis, current changing therapeutic options for pseudoaneurysm management, approved embolization agents, and clinical follow-up requirements to ensure adequate treatment will be discussed. Image-guided direct percutaneous and endovascular embolization of pseudoaneurysms are established treatment options with favorable success rates and minimal morbidity. The pendulum has now swung from invasive surgical repair of pseudoaneurysms to that of image-guided interventional radiology.

  14. Traumatic pseudoaneurysm of bulbourethral artery managed by coil embolization.

    PubMed

    Nadarajah, Jeyaseelan; Baliyan, Vinit; Yadav, Ajay Kumar; Kumar, Atin; Gamanagatti, Shivanand; Saini, Ashish; Gupta, Amit

    2015-04-01

    Urethral injury is a common form of urogenital trauma in males. Urethral injuries can be diagnosed with ease in emergency due to the presence of blood clot at external urethral meatus or inability to catheterize the urethra. Stricture formation is usual sequelae of such injuries. Uncontrolled urethral hemorrhage is a relatively rare complication which can present either as immediate or delayed. Such injuries can be managed conservatively in majority; however, if uncontrolled may require interventional management. Such patients usually have underlying pseudoaneurysm formation or arteriovenous fistula. Here, we are reporting a case of bulbar urethral injury which presented with delayed uncontrolled urethral hemorrhage. On angiography, pseudoaneurysm arising from left bulbourethral artery with active urethral extravasation was noted and was managed with coil embolization.

  15. [Secondary metabolites accumulating and geoherbs formation under enviromental stress].

    PubMed

    Huang, Lu-Qi; Guo, Lan-Ping

    2007-02-01

    This paper analyzed how habitat affected the formation of geoherbs after summarizing the influences of environmental stress on plants growth, especially on theirs secondary metabolites accumulating, and introducing 4 kinds hypothesis about environmental stress affects plants. It was then pointed out that environmental stress may have advantage on the formation of geoherbs. The stress effect hypothesis on forming geoherbs was brought forward, and the ways and methods on study the geoherbs under environmental stress was discussed.

  16. EFFECT OF ACIDITY ON SECONDARY ORGANIC AEROSOL FORMATION FROM ISOPRENE

    EPA Science Inventory

    The effect of particle-phase acidity on secondary organic aerosol (SOA) formation from isoprene is investigated in a laboratory chamber study, in which the acidity of the inorganic seed aerosol was controlled systematically. The observed enhancement in SOA mass concentration is c...

  17. The unusual angiographic course of intracranial pseudoaneurysms

    PubMed Central

    Zanaty, Mario; Chalouhi, Nohra; Jabbour, Pascal; Starke, Robert M.; Hasan, David

    2015-01-01

    Although rare, traumatic intracranial pseudoaneurysms remain one of the most difficult vascular lesions to diagnose and treat. A 55-year-old male patient underwent endoscopic endonasal transphenoidal resection for a pituitary macroadenoma. The operation was complicated by an arterial bleed. The initial angiogram revealed pseudoaneurysm of the anterior choroidal artery. Although the pseudoaneurysm completely disappeared on the second angiogram, it was surprisingly found to have enlarged on the third angiogram. The lesion was successfully treated with flow-diversion using a pipeline embolization device. The present case demonstrates that the natural history of iatrogenic pseudoaneurysms may be unpredictable and misleading. Traumatic pseudoaneurysms should, therefore, be carefully followed when conservative treatment is elected or when the lesion seems to have spontaneously regressed. Flow-diversion seems to be a reasonable treatment option. PMID:26425168

  18. Hemorrhage associated with hepatic artery pseudoaneurysms after regional chemotherapy with floxuridine: case report.

    PubMed

    Samaras, Panagiotis; Pfammatter, Thomas; Pestalozzi, Bernhard C

    2008-07-11

    Pseudoaneurysms of the hepatic artery are a rare complication in patients with primary or secondary liver tumors treated with intra-arterial chemotherapy. We present two patients who developed this complication after placement of a catheter system into the gastroduodenal artery and initiation of regional chemotherapy with floxuridine. Diagnosis was made after symptomatic bleeding occurred, necessitating emergency angiography with coil embolization. Pseudoaneurysms usually occur after mechanical damage of the vessel wall, but the chemical toxicity of floxuridine may add to the development of vascular impairment.

  19. Stent graft exclusion of a pseudoaneurysm in a Blalock-Taussig shunt.

    PubMed

    Sanchez-Recalde, Angel; Garzón, Gonzalo; Oliver, José M

    2010-08-01

    This case is the first report of slow-growing pseudoaneurysm after vessel dissection secondary to two stents implantation into classic Blalock Taussig shunt in a patient with pulmonary atresia and ventricular septal defect. Pseudoaneurysm was successfully excluded by a percutaneous approach with self-expandable stent graft deployment from the aorta to the middle of the Blalock Taussig shunt. Nearly 3 years after the procedure, the classic BT is patent, and there were no restenosis or thrombosis in spite of the very long length of the stented segment.

  20. Treatment of a Splenic Artery Pseudoaneurysm by Endoscopic Ultrasound-Guided Thrombin Injection

    SciTech Connect

    Robinson, Mark Richards, Dafydd; Carr, Nicholas

    2007-06-15

    We present a case of a splenic artery pseudoaneurysm secondary to pancreatitis that was successfully treated by transgastric injection of thrombin under endoscopic ultrasound guidance. There has been no recurrence on follow-up CT angiography, and thus complex surgery or endovascular intervention has been avoided.

  1. Subacute Staphylococcus epidermidis Bacterial Endocarditis Complicated by Mitral-Aortic Intervalvular Fibrosa Pseudoaneurysm

    DTIC Science & Technology

    2012-12-01

    Staphylococcus epidermidis Bacterial Endocarditis Complicated byMitral- Aortic Intervalvular Fibrosa Pseudoaneurysm Diane Elegino-Steffens,1 Amy Stratton,1...hypertension and congestive heart failure who underwent a bioprosthetic aortic valve replacement secondary to acute onset of aortic insufficiency...severe regurgitation, anterior and posterior leaflet vegetations, and scallop prolapse. There was also evidence of a mitral- aortic intervalvular fibrosa

  2. Diagnosis and management of ileocolic pseudoaneurysms.

    PubMed

    Desai, Sapan S; Dua, Anahita; Shortell, Cynthia K; Thacker, Julie K

    2012-09-01

    Ileocolic pseudoaneurysmal disease is a rare splanchnic aneurysm that affects 3 out of 100 000 patients, and only 7 cases have been described in the past 40 years in patients without preexisting connective tissue disorders. Abdominal pain is the most common presenting symptom and nearly 30% of patients present with hemorrhage. Ileocolic pseudoaneurysms are diagnosed by contrasted computed tomography scans and verified by arteriography. We present a case report and review of the literature in which a patient was initially managed by coil embolization, followed by laparotomy and suture ligation due to pseudoaneurysm rupture.

  3. Formation of halogen-induced secondary organic aerosol (XOA)

    NASA Astrophysics Data System (ADS)

    Kamilli, Katharina; Ofner, Johannes; Zetzsch, Cornelius; Held, Andreas

    2013-04-01

    Reactive halogen species (RHS) are very important due to their potential of stratospheric ozone depletion and surface ozone destruction. RHS seem to interact with precursors of secondary organic aerosol (SOA) similarly to common atmospheric oxidants like OH radicals and ozone. The potential interaction of RHS with preformed SOA has recently been studied (Ofner et al., 2012). Although aerosol formation from reaction of RHS with typical SOA precursors was previously studied (e.g. Cai et al., 2006), no data are available on bromine-induced aerosol formation from organic precursors yet. An aerosol smog-chamber was used to examine the halogen-induced secondary organic aerosol (XOA) formation under atmospheric conditions using simulated sunlight. With a concentration of 10 ppb for the organic precursor, 2 ppb for molecular chlorine, and 10 ppb for molecular bromine, the experimental setup is close to ambient conditions. By combined measurements of the aerosol size distribution, ozone and NOx mixing ratios, as well as the decay of the organic precursor, aerosol yields and aerosol growth rates were determined. The decay of the organic precursor was analyzed by capillary gas chromatography coupled with flame-ionization detection (GC-FID) and the aerosol size distribution was measured using a Scanning Mobility Particle Sizer (SMPS). Additionally, with the decay rate of the precursor and the calculated photolysis rates of molecular halogen species, based on the well-known spectrum of the solar simulator, mechanistic details on the XOA formation pathways can be determined. We observed XOA formation even at very low precursor and RHS concentrations with a diameter mode at 10-20 nm and a number concentration up to 1000000 particles cm-3. While the XOA formation from chlorine is very rapid, the interaction of bromine with the organic precursors is about five times slower. The aerosol yield reached maximum values of 0.01 for the reaction of chlorine with α-pinene and 0.0004 for

  4. Endovascular repair of post-traumatic, concomitant popliteal artery pseudoaneurysm and arteriovenous fistula

    PubMed Central

    Franz, Randall W; Jump, Mark A

    2009-01-01

    Popliteal artery trauma is a potentially devastating injury to the lower extremity with substantial associated morbidity. Pseudoaneurysm and arteriovenous fistula formation are complications of arterial injury that often present in a delayed fashion. Although these have traditionally been repaired using an open procedure, the growth of minimally invasive techniques has provided new therapeutic options for the treatment of such lesions. The present report discusses the successful treatment of concomitant popliteal pseudoaneurysm and arteriovenous fistula after delayed presentation by placing covered stents endovascularly. PMID:22477476

  5. Pseudoaneurysm of the superficial temporal artery.

    PubMed

    Nemade, S S; Eiman, M; Blondet, R; Beber, C; Nanes, M; Kirton, O C; Trainor, L D; Silverman, M A

    1996-08-01

    Ours is the first report of pseudoaneurysm of the superficial temporal in a 90-year-old woman. Although falls with associated head and scalp injuries in the geriatric population are common, pseudoaneurysm of the superficial temporal artery is rarely reported, probably due to the generally protected course of the superficial temporal artery across the skull. Clinicians' familiarity with this entity is important for early diagnosis and intervention.

  6. Extrarenal Transplant Artery Pseudoaneurysm: A Combined Therapeutic Approach

    SciTech Connect

    Poels, Jonathan A. D. Riley, Peter L.

    2008-03-15

    Extrarenal transplant pseudoaneurysms are rare, and treatment usually involves sacrificing of the transplant kidney. We report a case where combined use of a thrombotic agent and covered stents successfully excluded a pseudoaneurysm while preserving renal function.

  7. A Study on the Aqueous Formation of Secondary Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Sinclair, K.; Tsigaridis, K.

    2013-12-01

    The effect aerosols have on radiative forcing in the atmosphere is recognized as one of the largest uncertainties in the radiation budget. About 80% of organic aerosol mass in the atmosphere is estimated to be created though secondary processes. Recently, the aqueous formation of secondary organic aerosols (SOA) has become recognized as important when considering the source, transformation and radiative impacts of SOA. This work focuses on implementing a mechanism for aqueous SOA formation that can be used in atmospheric chemistry and models of all scales, from box to global. A box model containing a simplified chemical mechanism for the aqueous production of precursors of aqueous SOA (Myriokefalitakis et al. (2011) is coupled to gas-phase chemistry which uses the carbon bond mechanism (CBM) IV is presented. The model implements aqueous chemistry of soluble gases, both in-cloud and aerosol water, including organic compounds such as glyoxal and methylglyoxal, which have been shown as potentially significant sources for dissolved secondary organic aerosols. This mechanism implements aqueous phase mass transfer and molecular dissociation. The model's performance is evaluated against previous box model studies from the literature. A comparison is conducted between the detailed GAMMA model (McNeill et al., 2012), which is constrained with chamber experiments and the one developed here. The model output under different atmospheric conditions is explored and differences and sensitivities are assessed. The objective of this work is to create a robust framework for simulating aqueous phase formation of SOA and maximizing the computational efficiency of the model, while maintaining accuracy, in order to later use the exact mechanism in global climate simulations.

  8. Formation of secondary organic aerosols from the ozonolysis of dihydrofurans

    NASA Astrophysics Data System (ADS)

    Diaz-de-Mera, Yolanda; Aranda, Alfonso; Bracco, Larisa; Rodriguez, Diana; Rodriguez, Ana

    2017-02-01

    In this work we report the study of the ozonolysis of 2,5-dihydrofuran and 2,3-dihydrofuran and the reaction conditions leading to the formation of secondary organic aerosols. The reactions have been carried out in a Teflon chamber filled with synthetic air mixtures at atmospheric pressure and room temperature. The ozonolysis only produced particles in the presence of SO2. Rising relative humidity from 0 to 40 % had no effect on the production of secondary organic aerosol in the case of 2,5-dihydrofuran, while it reduced the particle number and particle mass concentrations from the 2,3-dihydrofuran ozonolysis. The water-to-SO2 rate constant ratio for the 2,3-dihydrofuran Criegee intermediate was derived from the secondary organic aerosol (SOA) yields in experiments with different relative humidity values, kH2O/kSO2 = (9.8 ± 3.7) × 10-5. The experimental results show that SO3 may not be the only intermediate involved in the formation or growth of new particles in contrast to the data reported for other Criegee intermediate-SO2 reactions. For the studied reactions, SO2 concentrations remained constant during the experiments, behaving as a catalyst in the production of condensable products. Computational calculations also show that the stabilised Criegee intermediates from the ozonolysis reaction of both 2,5-dihydrofuran and 2,3-dihydrofuran may react with SO2, resulting in the regeneration of SO2 and the formation of low-volatility organic acids.

  9. Formation and Applications of the Secondary Fiber Bragg Grating †

    PubMed Central

    Guan, Bai-Ou; Ran, Yang; Feng, Fu-Rong; Jin, Long

    2017-01-01

    Being one of the most proven fiber optic devices, the fiber Bragg grating has developed continually to extend its applications, particularly in extreme environments. Accompanying the growth of Type-IIa Bragg gratings in some active fibers, a new resonance appears at the shorter wavelength. This new type of grating was named “secondary Bragg grating” (SBG). This paper describes the formation and applications of the SBGs. The formation of the SBG is attributed to the intracore Talbot-type-fringes as a result of multi-order diffractions of the inscribing beams. The SBG presents a variety of interesting characteristics, including dip merge, high-temperature resistance, distinct temperature response, and the strong higher-order harmonic reflection. These features enable its promising applications in fiber lasers and fiber sensing technology. PMID:28218697

  10. Surgical Treatment of Left Ventricular Pseudoaneurysm

    PubMed Central

    Mujanovic, Emir; Bergsland, Jacob; Avdic, Sevleta; Stanimirovic-Mujanovic, Sanja; Kovacevic-Preradovic, Tamara; Kabil, Emir

    2014-01-01

    Introduction: Left ventricular pseudoaneurysm is a rare condition because in most instances ventricular free-wall rupture leads to fatal pericardial tamponade. Rupture of the free wall of the left ventricle is a cata­strophic complication of myocardial infarction, occurring in approximately 4% of pa­tients with infarcts, resulting in immediate collapse of the patient and electromechanical dissociation. In rare cases the rupture is contained by pericardial and fibrous tissue, and the result is a pseudoaneurysm. The left ventricular pseudoaneurysm contains only pericardial and fibrous elements in its wall-no myocardial tissue. Because such aneurysms have a strong tendency to rupture, this disorder may lead to death if it is left surgically untreated. Case report: In this case report, we present a patient who underwent successful repair of a left ventricular pseudoaneurysm, which followed a myocardial infarction that was caused by occlusion of the left circumflex coronary artery. Although repair of left ventricular pseudoaneurysm is still a surgical challenge, it can be performed with acceptable results in most patients. PMID:25568538

  11. Transcatheter Embolization of Pseudoaneurysms Complicating Pancreatitis

    SciTech Connect

    Golzarian, Jafar; Nicaise, Nicole; Deviere, Jacques; Ghysels, Marc; Wery, Didier; Dussaussois, Luc; Gansbeke, Daniel van; Struyven, Julien

    1997-11-15

    Purpose: To evaluate the therapeutic role of angiography in patients with pseudoaneurysms complicating pancreatitis. Methods: Thirteen symptomatic pseudoaneurysms were treated in nine patients with pancreatitis. Eight patients had chronic pancreatitis and pseudocyst and one had acute pancreatitis. Clinical presentation included gastrointestinal bleeding in seven patients and epigastric pain without bleeding in two. All patients underwent transcatheter embolization. Results: Transcatheter embolization resulted in symptomatic resolution in all patients. Rebleeding occurred in two patients, 18 and 28 days after embolization respectively, and was successfully treated by repeated emnbolization. One patient with severe pancreatitis died from sepsis 28 days after embolization. Follow-up was then available for eight patients with no relapse of bleeding after a mean follow-up of 32 months (range 9-48 months). Conclusion: Transcatheter embolization is safe and effective in the management of pseudoaneurysms complicating pancreatitis.

  12. SECONDARY ORGANIC AEROSOL FORMATION FROM THE IRRADIATION OF SIMULATED AUTOMOBILE EXHAUST

    EPA Science Inventory

    A laboratory study was conducted to evaluate the potential for secondary organic aerosol formation from emissions from automotive exhaust. The goal was to determine to what extent photochemical oxidation products of these hydrocarbons contribute to secondary organic aerosol (SO...

  13. Secondary organic aerosol formation from road vehicle emissions

    NASA Astrophysics Data System (ADS)

    Pieber, Simone M.; Platt, Stephen M.; El Haddad, Imad; Zardini, Alessandro A.; Suarez-Bertoa, Ricardo; Slowik, Jay G.; Huang, Ru-Jin; Hellebust, Stig; Temime-Roussel, Brice; Marchand, Nicolas; Drinovec, Luca; Mocnik, Grisa; Baltensperger, Urs; Astorga, Covadogna; Prévôt, André S. H.

    2014-05-01

    Organic aerosol particles (OA) are a major fraction of the submicron particulate matter. OA consists of directly emitted primary (POA) and secondary OA (SOA). SOA is formed in-situ in the atmosphere via the reaction of volatile organic precursors. The partitioning of SOA species depends not only on the exposure to oxidants, but for instance also on temperature, relative humidity (RH), and the absorptive mass chemical composition (presence of inorganics) and concentration. Vehicle exhaust is a known source of POA and likely contributes to SOA formation in urban areas [1;2]. This has recently been estimated by (i) analyzing ambient data from urban areas combined with fuel consumption data [3], (ii) by examining the chemical composition of raw fuels [4], or (iii) smog chamber studies [5, 6]. Contradictory and thus somewhat controversial results in the relative quantity of SOA from diesel vs. gasoline vehicle exhaust were observed. In order to elucidate the impact of variable ambient conditions on the potential SOA formation of vehicle exhaust, and its relation to the emitted gas phase species, we studied SOA formed from the exhaust of passenger cars and trucks as a function of fuel and engine type (gasoline, diesel) at different temperatures (T 22 vs. -7oC) and RH (40 vs. 90%), as well as with different levels of inorganic salt concentrations. The exhaust was sampled at the tailpipe during regulatory driving cycles on chassis dynamometers, diluted (200 - 400x) and introduced into the PSI mobile smog chamber [6], where the emissions were subjected to simulated atmospheric ageing. Particle phase instruments (HR-ToF-AMS, aethalometers, CPC, SMPS) and gas phase instruments (PTR-TOF-MS, CO, CO2, CH4, THC, NH3 and other gases) were used online during the experiments. We found that gasoline emissions, because of cold starts, were generally larger than diesel, especially during cold temperatures driving cycles. Gasoline vehicles also showed the highest SOA formation

  14. Secondary Organic Aerosol Formation from the Photooxidation of Naphthalene

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Chen, Y.; Wenger, J.

    2009-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous air pollutants that are released into the atmosphere as a by-product of combustion processes. The gas-phase PAHs can be chemically transformed via reaction with the hydroxyl radical to produce a range of oxidised organic compounds and other pollutants such as ozone and secondary organic aerosol (SOA). Epidemiological studies have established that exposure to this type of air pollution is associated with damaging effects on the respiratory and cardiovascular systems, and can lead to asthma, oxidative stress, health deterioration and even death. The major anthropogenic source of SOA in urban areas is believed to be aromatic hydrocarbons, which are present in automobile fuels and are used as solvents. As a result, research is currently being performed on the characterisation of SOA produced from aromatic hydrocarbons such as toluene, the xylenes and trimethylbenzenes. However, significant amounts of PAHs are also released into urban areas from automobile emissions and the combustion of fossil fuels for home heating. Naphthalene is regularly cited as the most abundant PAH in polluted urban air, with typical ambient air concentrations of 0.05 - 0.20 parts per billion (ppbV) in European cities, comparable to the xylenes. Since naphthalene reacts in an analogous manner to monocyclic aromatic compounds then it is also expected to make a significant contribution to ambient SOA. However, the yield and chemical composition of SOA produced from the atmospheric degradation of naphthalene is not well known. In this presentation, the effects of NOx level and relative humidity on the SOA formation from the phootooixdation of naphthalene will be presented. A series of experiments has been performed in a large atmospheric simulation chamber equipped with a gas chromatograph and analyzers for monitoring nitrogen oxides (NOx) and ozone. SOA formation from the photooxidation of naphthalene was measured using a scanning mobility

  15. Endovascular Stent-Grafting for Infected Iliac Artery Pseudoaneurysms

    SciTech Connect

    Sanada, Junichiro Matsui, Osamu; Arakawa, Fumitaka; Tawara, Mari; Endo, Tamao; Ito, Hiroshi; Ushijima, Satoshi; Endo, Masamitsu; Ikeda, Masahiro; Miyazu, Katsuyuki

    2005-01-15

    We report two cases of acutely infected pseudoaneurysms of the iliac arteries, successfully treated with endovascular stent-grafting. Two patients underwent stent-graft treatment for erosive rupture of the iliac artery caused by surrounding infection. The first case is that of a 61-year-old man who had undergone Miles' operation for an advanced rectal cancer. Postoperatively, he developed intrapelvic abscess formation, from which methicillin-resistant Staphylococcus aureus was cultured, followed by rupture of the right external iliac artery. The second case is that of a 60-year-old man who had a pseudoaneurysm of the left common iliac artery, which was contiguous with a left psoas muscle abscess, from which Streptococcus agalactiae was cultured. Both patients were successfully treated with only a stent-graft and antibiotic therapy, and remained symptom-free 12 months and 10 months later. Although endovascular stent-grafting should not be considered standard therapy for infected aneurysms, our cases suggest that it can result in repair of infected aneurysms even in the uncontrolled active stage.

  16. Secondary Organic Aerosol Formation from the Ozonolysis of Cycloalkenes

    NASA Astrophysics Data System (ADS)

    Keywood, M.; Varutbangkul, V.; Gao, S.; Brechtel, F.; Bahreini, R.; Flagan, R. C.; Seinfeld, J. H.

    2003-12-01

    Secondary organic aerosol (SOA) is ubiquitous in the atmosphere being present in both urban and remote locations and exerting influence on human health, visibility and climate. Despite its importance, our understanding of SOA formation still lacks essential elements, limiting our understanding of the effect of SOA on climate forcing. While there do exist experimental data on SOA yields from both biogenic and anthropogenic precursor compounds, it is difficult to extend these results to predict the aerosol-forming potential of precursor compounds not yet studied. In response to this, a series of chamber experiments were carried out in the Caltech Indoor Chamber Facility, where compounds from the cycloalkene and methyl-substituted cycloalkene families were oxidized by ozone in the dark. The reactions were carried out in dual 28 m3 teflon chambers at 20oC and relative humidity below 5%, in the presence of ammonium sulfate seed aerosol. Cyclohexane was used as a scavenger to prevent side oxidation reactions with OH radicals, generated during ozonolysis of the cycloalkene. While cycloalkenes may not be important precursors for SOA formation in the ambient atmosphere, the system was chosen for its simplicity relative to atmospherically relevant SOA precursors such as the biogenic monoterpenes and sesquiterpenes. Cycloalkenes may be seen as the simplified structures on which these more complicated compounds are based. The compounds reacted included the cycloalkenes: cyclopentene, cyclohexene, cycloheptene and cyclooctene, the methyl-substituted cycloalkenes: 1-methyl-1-cyclohexene, 3-methyl-1-cyclohexene, 1-methy-1-cycloheptene and1-methyl-1-cylopentene, and other related classes of hydrocarbons: methylene cyclohexane and terpinolene. Data collected include aerosol yield, chemical composition and hygroscopic behaviour. The effect of the precursor hydrocarbon structure on these properties of the SOA will be discussed.

  17. Thyrocervical trunk pseudoaneurysm following central venous catheterization.

    PubMed

    Mazzei, Valerio; Benvenuto, Domenico; Gagliardi, Massimo; Guarracini, Stefano; Di Mauro, Michele

    2011-11-01

    A 71-year-old female developed a painless neck mass three months following an aortic valve replacement, mitral commissurotomy, and coronary artery bypass. A cervical trunk angio revealed a pseudoaneurysm supplied from a branch of the thyrocervical trunk, which was successfully excised.

  18. Complication of Behcet's disease: spontaneous aortic pseudoaneurysm.

    PubMed

    Ugurlucan, Murat; Sayin, Omer Ali; Surmen, Benguhan; Kafali, Eylul; Basaran, Murat; Alpagut, Ufuk; Dayioglu, Enver; Onursal, Ertan

    2006-01-01

    Behcet's disease is an autoimmune multisystemic disorder based on vasculitis. In this disease, the most important predictor of morbidity and mortality is the vascular complications. Appropriate surgical interventions are critical and must be planned strategically. Here, we will describe a very rare complication of the disease; spontaneous aortic pseudoaneurysm in a 33-year-old patient.

  19. Clinical Analysis of Traumatic Cerebral Pseudoaneurysms

    PubMed Central

    Moon, Tae Hun; Kim, Sung Han; Huh, Seung Kon

    2015-01-01

    Objective Traumatic pseudoaneurysms are rare but life-threatening lesions. We investigated the patients with these lesions to clarify their clinical characteristics and therapeutic strategies and we also reviewed the literatures on the treatment principles, possible options, and outcomes. Methods There were a total of 8 patients who were treated with traumatic intracranial pseudoaneurysms between April 1980 and January 2009. Medical charts and the imaging studies were reviewed for analysis. The outcome was measured with modified Rankin Scale (mRS) score at 6 months after treatment. Results All 8 patients were male and the mean age was 25 years old. Six of those were located at the cavernous segment of the internal carotid artery (ICA) and the other 2 was located at the M2 segment of middle cerebral artery. The causes of trauma were car accidents in 6, penetrating injury through the orbit in 1, and slip down injury in 1 patient. Massive epistaxis or hematemesis occurred in all patients with a pseudoaneurysm at the cavernous and ophthalmic segment of the ICA. All 6 patients of the cavernous and ophthalmic ICA group showed favorable outcome of mRS 0 to 1. The outcome of patients with middle cerebral artery pseudoaneurysm was mRS 2 to 3. Conclusion Upon prompt diagnosis and proper treatment planning, it is possible to achieve favorable outcome in these patients. Lesions located at the cavernous segment of the ICA favored endovascular treatment while those at the middle cerebral artery favored surgical treatment. PMID:27169077

  20. The Transcriptomics of Secondary Growth and Wood Formation in Conifers

    PubMed Central

    Carvalho, Ana; Paiva, Jorge; Louzada, José; Lima-Brito, José

    2013-01-01

    In the last years, forestry scientists have adapted genomics and next-generation sequencing (NGS) technologies to the search for candidate genes related to the transcriptomics of secondary growth and wood formation in several tree species. Gymnosperms, in particular, the conifers, are ecologically and economically important, namely, for the production of wood and other forestry end products. Until very recently, no whole genome sequencing of a conifer genome was available. Due to the gradual improvement of the NGS technologies and inherent bioinformatics tools, two draft assemblies of the whole genomes sequence of Picea abies and Picea glauca arose in the current year. These draft genome assemblies will bring new insights about the structure, content, and evolution of the conifer genomes. Furthermore, new directions in the forestry, breeding and research of conifers will be discussed in the following. The identification of genes associated with the xylem transcriptome and the knowledge of their regulatory mechanisms will provide less time-consuming breeding cycles and a high accuracy for the selection of traits related to wood production and quality. PMID:24288610

  1. The transcriptomics of secondary growth and wood formation in conifers.

    PubMed

    Carvalho, Ana; Paiva, Jorge; Louzada, José; Lima-Brito, José

    2013-01-01

    In the last years, forestry scientists have adapted genomics and next-generation sequencing (NGS) technologies to the search for candidate genes related to the transcriptomics of secondary growth and wood formation in several tree species. Gymnosperms, in particular, the conifers, are ecologically and economically important, namely, for the production of wood and other forestry end products. Until very recently, no whole genome sequencing of a conifer genome was available. Due to the gradual improvement of the NGS technologies and inherent bioinformatics tools, two draft assemblies of the whole genomes sequence of Picea abies and Picea glauca arose in the current year. These draft genome assemblies will bring new insights about the structure, content, and evolution of the conifer genomes. Furthermore, new directions in the forestry, breeding and research of conifers will be discussed in the following. The identification of genes associated with the xylem transcriptome and the knowledge of their regulatory mechanisms will provide less time-consuming breeding cycles and a high accuracy for the selection of traits related to wood production and quality.

  2. Laboratory studies on secondary organic aerosol formation from terpenes.

    PubMed

    Iinuma, Yoshiteru; Böge, Olaf; Miao, Yunkun; Sierau, Berko; Gnauk, Thomas; Herrmann, Hartmut

    2005-01-01

    The formation of secondary organic aerosol (SOA) following the ozonolysis of terpene has been investigated intensively in recent years. The enhancement of SOA yields from the acid catalysed reactions of organics on aerosol surfaces or in the bulk particle phase has been receiving great attention. Recent studies show that the presence of acidic seed particles increases the SOA yield significantly (M. S. Jang and R. M. Kamens, Environ. Sci. Technol., 2001, 35, 4758, ref. 1; M. S. Jang, N. M. Czoschke, S. Lee and R. M. Kamens, Science, 2002, 298, 814, ref. 2; N. M. Czoschke, M. Jang and R. M. Kamens, Atmos. Environ., 2003, 37, 4287, ref. 3; M. S. Jang, B. Carroll, B. Chandramouli and R. M. Kamens, Environ. Sci. Technol., 2003, 37, 3828, ref. 4; Y. Iinuma, O. Böge, T. Gnauk and H. Herrmann, Atmos. Environ., 2004, 38, 761, ref. 5; S. Gao, M. Keywood, N. L. Ng, J. Surratt, V. Varutbangkul, R. Bahreini, R. C. Flagan and J. H. Seinfeld, J. Phys. Chem. A, 2004, 108, 10147, ref. 6). More detailed studies report the formation of higher molecular weight products in SOA (refs. 5 and 6; M. P. Tolocka, M. Jang, J. M. Ginter, F. J. Cox, R. M. Kamens and M. V. Johnston, Environ. Sci. Technol., 2004, 38, 1428, ref. 7; S. Gao, N. L. Ng, M. Keywood, V. Varutbangkul, R. Bahreini, A. Nenes, J. He, K. Y. Yoo, J. L. Beauchamp, R. P. Hodyss, R. C. Flagan and J. H. Seinfeld, Environ. Sci. Technol., 2004, 38, 6582, ref. 8) which could result in a non-reversible uptake of organics into the particle phase. Most of the past studies concentrated on the characterisation of the yields of enhanced SOA and its composition from ozonolysis of terpenes in the presence or absence of acidic and neutral seed particles. Recent findings from cyclohexene ozonolysis show that the presence of OH scavengers can also significantly influence the SOA yield. Our new results from the IfT chemistry department aerosol chamber on terpene ozonolysis in the presence of OH scavengers show that the presence of hydroxyl

  3. Secondary brown carbon formation via the dicarbonyl imine pathway: nitrogen heterocycle formation and synergistic effects.

    PubMed

    Kampf, C J; Filippi, A; Zuth, C; Hoffmann, T; Opatz, T

    2016-07-21

    Dicarbonyls are known to be important precursors of so-called atmospheric brown carbon, significantly affecting aerosol optical properties and radiative forcing. In this systematic study we report the formation of light-absorbing nitrogen containing compounds from simple 1,2-, 1,3-, 1,4-, and 1,5-dicarbonyl + amine reactions. A combination of spectrophotometric and mass spectrometric techniques was used to characterize reaction products in solutions mimicking atmospheric particulates. Experiments with individual dicarbonyls and dicarbonyl mixtures in ammonium sulfate and glycine solutions demonstrate that nitrogen heterocycles are common structural motifs of brown carbon chromophores formed in such reaction systems. 1,4- and 1,5-dicarbonyl reaction systems, which were used as surrogates for terpene ozonolysis products, showed rapid formation of light-absorbing material and products with absorbance maxima at ∼450 nm. Synergistic effects on absorbance properties were observed in mixed (di-)carbonyl experiments, as indicated by the formation of a strong absorber in ammonium sulfate solutions containing acetaldehyde and acetylacetone. This cross-reaction oligomer shows an absorbance maximum at 385 nm, relevant for the actinic flux region of the atmosphere. This study demonstrates the complexity of secondary brown carbon formation via the imine pathway and highlights that cross-reactions with synergistic effects have to be considered an important pathway for atmospheric BrC formation.

  4. Subclavian artery pseudoaneurysm complicating central venous catheterization: endovascular treatment with Amplatzer Vascular Plug 4 and covered stent.

    PubMed

    Rossi, Umberto G; Petrocelli, Francesco; Ferro, Carlo

    2013-12-01

    Central venous catheterization is a routine vascular access procedure; however, it may be associated with life-threatening complications such as arterial puncture, leading to pseudoaneurysm formation. We report a case of a 41-year-old female that developed an iatrogenic left subclavian pseudoaneurysm complicating the attempt of left internal jugular vein cannulation for temporary hemodialysis therapy. The patient underwent urgent endovascular treatment with deployment of covered stent into the left subclavian artery (SCA) after embolization of the origin of the left internal mammary artery with Amplatzer Vascular Plug 4. The patient's recovery was unremarkable. Follow-up till 24 months reveals total exclusion of the pseudoaneurysm of the left SCA with patency of the distal branches.

  5. Transarterial Coil Embolization of a Symptomatic Posttraumatic Plantar Pseudoaneurysm

    PubMed Central

    Beyer, Lukas Philipp; Wohlgemuth, Walter A.; Müller-Wille, René

    2015-01-01

    Posttraumatic pseudoaneurysms of the lateral plantar artery are rare. We report the case of a 31-year-old woman with a painful pseudoaneurysm of the lateral plantar artery resulting from a deep plantar cut injury. The pseudoaneurysm was successfully treated by performing a transarterial “frontdoor-backdoor” coil embolization technique, which is a minimally invasive alternative to conventional ligature of the artery. PMID:25874151

  6. Endovascular Repair of a Large Profunda Femoris Artery Pseudoaneurysm

    PubMed Central

    Khalid, Ahsan Syed; Ghanem, Omar M.; Mojtaba Gashti, Seyed

    2014-01-01

    Profunda femoris artery aneurysms and pseudoaneurysms are a rare cause of peripheral arterial aneurysms but their risk of rupture is quite high. We have presented a case of a left lower leg pseudoaneurysm. We have shown that endovascular repair with angioplasty and stenting is a suitable treatment method for such a pseudoaneurysm. Due to the limited data on this disease, we suggest multi-institute collaboration to identify and standardize management for the treatment. PMID:24716098

  7. Kinetics, products, and mechanisms of secondary organic aerosol formation.

    PubMed

    Ziemann, Paul J; Atkinson, Roger

    2012-10-07

    Secondary organic aerosol (SOA) is formed in the atmosphere when volatile organic compounds (VOCs) emitted from anthropogenic and biogenic sources are oxidized by reactions with OH radicals, O(3), NO(3) radicals, or Cl atoms to form less volatile products that subsequently partition into aerosol particles. Once in particles, these organic compounds can undergo heterogenous/multiphase reactions to form more highly oxidized or oligomeric products. SOA comprises a large fraction of atmospheric aerosol mass and can have significant effects on atmospheric chemistry, visibility, human health, and climate. Previous articles have reviewed the kinetics, products, and mechanisms of atmospheric VOC reactions and the general chemistry and physics involved in SOA formation. In this article we present a detailed review of VOC and heterogeneous/multiphase chemistry as they apply to SOA formation, with a focus on the effects of VOC molecular structure on the kinetics of initial reactions with the major atmospheric oxidants, the subsequent reactions of alkyl, alkyl peroxy, and alkoxy radical intermediates, and the composition of the resulting products. Structural features of reactants and products discussed include compound carbon number; linear, branched, and cyclic configurations; the presence of C[double bond, length as m-dash]C bonds and aromatic rings; and functional groups such as carbonyl, hydroxyl, ester, hydroxperoxy, carboxyl, peroxycarboxyl, nitrate, and peroxynitrate. The intention of this review is to provide atmospheric chemists with sufficient information to understand the dominant pathways by which the major classes of atmospheric VOCs react to form SOA products, and the further reactions of these products in particles. This will allow reasonable predictions to be made, based on molecular structure, about the kinetics, products, and mechanisms of VOC and heterogeneous/multiphase reactions, including the effects of important variables such as VOC, oxidant, and NO

  8. Surgical Treatment of Post-Infarction Left Ventricular Pseudoaneurysm

    PubMed Central

    Eren, Ercan; Bozbuga, Nilgun; Toker, Mehmet Erdem; Keles, Cuneyt; Rabus, Murat Bulent; Yildirim, Ozgur; Guler, Mustafa; Balkanay, Mehmet; Isik, Omer; Yakut, Cevat

    2007-01-01

    Herein, we present a retrospective analysis of our experience with acquired pseudoaneurysms of the left ventricle over a 20-year period. From February 1985 through September 2004, 14 patients underwent operation for left ventricular pseudoaneurysm in our clinic. All pseudoaneurysms (12 chronic, 2 acute) were caused by myocardial infarction. The mean interval between myocardial infarction and diagnosis of pseudoaneurysm was 7 months (range, 1–11 mo). The pseudoaneurysm was located in the inferior or posterolateral wall in 11 of 14 patients (78.6%). In all patients, the pseudoaneurysm was resected and the ventricular wall defect was closed with direct suture (6 patients) or a patch (8 patients). Most patients had 3-vessel coronary artery disease. Coronary artery bypass grafting was performed in all patients. Five patients died (postoperative mortality rate, 35.7%) after repair of a pseudoaneurysm (post-infarction, 2 patients; chronic, 3 patients). Two patients died during follow-up (median, 42 mo), due to cancer in 1 patient and sudden death in the other. Although repair of left ventricular pseudoaneurysm is still a surgical challenge, it can be performed with acceptable results in most patients. Surgical repair is warranted particularly in cases of large or expanding pseudoaneurysms because of the propensity for fatal rupture. PMID:17420793

  9. Repair of anastomotic abdominal aortic pseudoaneurysm utilizing sequential AneuRx aortic cuffs in an overlapping configuration.

    PubMed

    Zhou, Wei; Bush, Ruth L; Bhama, Jay K; Lin, Peter H; Safaya, Rakesh; Lumsden, Alan B

    2006-01-01

    Anastomotic aortic pseudoaneurysm is a known late complication following aortic repair and presents a considerable surgical challenge. We herein evaluate the endovascular alternative of using sequential AneuRx aortic cuffs to bridge the degenerative anastomotic pseudoaneurysms as a definitive treatment. Over a 3-year period, six patients with a mean age of 68.7 years (range 58-75) were identified who had proximal anastomotic aortic pseudoaneurysms secondary to previously implanted bifurcated aortic grafts (mean 15, range 12-20 years) following open surgical correction of aortoiliac occlusive disease. Five patients (83%) presented with concomitant palpable femoral anastomotic pseudoaneurysms and one patient (16%) had a pulsatile abdominal mass. All patients had computed tomographic (CT) scans confirming proximal anastomotic pseudoaneuryms without evidence of infection. The mean diameter of the pseudoaneurysms was 5.3 cm (range 4.0-7.0). Five patients were treated with endovascular methods, while one patient was not suitable for endovascular repair due to the diameter of the native aorta as seen on imaging study at the time of the procedure. AneuRx aortic extender cuffs (3.75 cm length) were deployed sequentially in five patients via a femoral approach. Devices were overlapped approximately 1.5 cm in order to achieve total exclusion of the pseudoaneurysms, and all concomitant femoral aneurysms were repaired surgically at the same time. Successful exclusion of the anastomotic pseudoaneurysm was achieved in four patients (80%) using a combination of two or three overlapping aortic cuffs. One patient had a small residual endoleak that had sealed by 1 month, evidenced by follow-up CT. The renal arteries were preserved in all patients. The average estimated blood loss and operative time were 355 +/- 25 cc and 84 +/- 21 min, respectively. The average length of hospital stay was 2.1 days, and there was no mortality or major morbidity. All patients underwent CT scanning

  10. Secondary organic aerosol formation and source apportionment in Southeast Texas

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Ying, Qi

    2011-06-01

    The latest version of US EPA's Community Multi-scale Air Quality (CMAQ v4.7) model with the most recent update on secondary organic aerosol (SOA) formation pathways was adapted into a source-oriented modeling framework to determine the contributions of different emission sources to SOA concentrations from a carbon source perspective in Southeast Texas during the 2000 Texas Air Quality Study (TexAQS 2000) from August 25 to September 5, 2000. A comparison of the VOC and SOA predictions with observations shows that anthropogenic emissions of long chain alkanes and aromatics are likely underestimated in the EPA's Clean Air Interstate Rule (CAIR) inventory and the current SOA mechanism in CMAQ still under-predicts SOA. The peak SOA concentrations measured at La Porte are more accurately predicted by increasing the emissions of the anthropogenic SOA precursors by a factor of 5 although the overall precursor concentrations are better predicted by increasing the emissions by a factor of 2. A linear correlation between SOA and odd oxygen (ΔSOA/ΔOx = 23.0-28.4 μg m-3/ppm Ox) can be found when they are formed simultaneously in the air masses passing the urban Houston area on high SOA days. Based on the adjusted emissions (a factor of 2 increase in the alkane and aromatics precursor emissions), approximately 20% of the total SOA in the Houston-Galveston Bay area is due to anthropogenic sources. Solvent utilization and gasoline engines are the main anthropogenic sources. SOA from alkanes and aromatics accounts for approximately 2-4% and 5-9% of total SOA, respectively. The predicted overall anthropogenic SOA concentrations are not sensitive to the half-life time used to calculate the conversion rate of semi-volatile organic compounds to non-volatile oligomers in the particle phase. The main precursors of biogenic SOA are sesquiterpenes, which contribute to approximately 12-35% of total SOA. Monoterpenes contribute to 3-14% and isoprene accounts for approximately 6-9% of the

  11. [Pseudoaneurysm of saphenous vein graft after CABG].

    PubMed

    Nakamura, T; Shimamoto, M; Yamazaki, F; Fujita, S; Yoshimura, T; Ueno, T; Shinozaki, T

    1995-04-01

    A 69-year-old man was admitted because of angina pectoris and thoracic descending aorta aneurysm. Staged operations were planned. First, he underwent CABG (coronary artery bypass grafting) with SVGs (saphenous vein grafts) to #4 PD, #7 and #12. Aprotinin was administrated to reduce blood loss. The routine postoperative graft angiography and enhanced CT showed a pseudoaneurysm in the SVG to #4 PD. We planned an elective operation of pseudoaneurysm repair and graft replacement of thoracic descending aorta. Also in this second operation, continuous infusion of aprotinin was started after the induction of anesthesia. About 30 minutes later, he suddenly fell in shock and cardiac arrest. Partial cardiopulmonary bypass was established and median sternotomy was performed. In the mediastinum, no bleeding was found. We found out a bleeding point of the SVG to #4 PD and a hemostatic clip on the right ventricule, and closed the bleeding point with suture. The cause of the pseudoaneurysm seemed to be defluxion of the hemostatic clip for a side brunch of the SVG. The cause of the preoperative shock may be an anaphylaxis to readministrated aprotinin.

  12. Left ventricular pseudoaneurysm perceived as a left lung mass

    PubMed Central

    Yaliniz, Hafize; Gocen, Ugur; Atalay, Atakan; Salih, Orhan Kemal

    2016-01-01

    Left ventricular pseudoaneurysm is a rare complication of aneurysmectomy. We present a case of a surgically treated left ventricular pseudoaneurysm, which was diagnosed three years after coronary artery bypass grafting and left ventricular aneurysmectomy. The presenting symptoms, diagnostic evaluation, and surgical repair are described. PMID:27516793

  13. Surgical exclusion of postsurgical pseudoaneurysm of the ascending aorta

    PubMed Central

    Barik, Ramachandra; Patnaik, Amar Narayana; Kumar, Ravintula Venkata; Mohapatra, Rudra Prasad; Medep, Vikas; Nemani, Lalita

    2014-01-01

    Pseudoaneurysm of ascending aorta after cardiac surgery is rare in children. We report a case of successful surgical exclusion of ascending aortic pseudoaneurysm in a 15-year-old boy. The neck of the aneurysm was in close proximity to the right coronary artery (RCA). PMID:24987261

  14. EVALUATION OF SECONDARY ORGANIC AEROSOL FORMATION IN WINTER. (R823514)

    EPA Science Inventory

    Three different methods are used to predict secondary organic aerosol (SOA)
    concentrations in the San Joaquin Valley of California during the winter of 1995-1996 [Integrated
    Monitoring Study, (IMS95)]. The first of these methods estimates SOA by using elemental carbon as

  15. FORMATION MECHANISMS FOR SECONDARY ORGANIC AEROSOL IN AMBIENT AIR

    EPA Science Inventory

    An laboratory and field research program is underway at the NERL to characterize secondary organic carbon in PM2.5 which is formed through chemical reactions in the atmosphere. Information from this study will provide critical data needed to improve the treatment of SO...

  16. SECONDARY ORGANIC AEROSOL FORMATION FROM MIXTURES OF BIOGENIC HYDROCARBONS

    EPA Science Inventory

    In this work the influence of hydrocarbon mixtures on the overall Secondary Organic Aerosol yield is investigated. Photochemical reaction experiments were conducted using mixtures of a-pinene, isoprene and propene in the presence of NOx. Results of the experiments show...

  17. Formation of Secondary Ca-Fe-Rich Assemblages in CV Chondrites

    NASA Astrophysics Data System (ADS)

    Ganino, C.; Libourel, G.

    2016-08-01

    Chondrites have multiplied evidences for metasomatic processes during the early solar system formation. Diversity in secondary Ca-Fe silicate provides information on T-X conditions and the open/closed-system behavior.

  18. Thrombin Injection Failure with Subsequent Successful Stent-Graft Placement for the Treatment of an Extracranial Internal Carotid Pseudoaneurysm in a 5-Year-Old Child

    SciTech Connect

    Garcia-Monaco, R. D.; Kohan, A. A.; Martinez-Corvalan, M. P.; Cacchiarelli, N.; Peralta, O.; Wahren, C. G.

    2012-06-15

    Internal carotid artery pseudoaneurysm is a rare life-threatening condition that may develop in different clinical situations. We report the case of an extracranial internal carotid artery pseudoaneurysm secondary to a throat infection in a pediatric patient that was initially treated with percutaneous thrombin injection under ultrasound guidance. However, recanalization occurred at 48 h, and definitive treatment was then performed by endovascular stent-graft placement. We briefly review the clinical characteristics of this uncommon clinical condition as well as the treatment options.

  19. Examining the Use of Audience Response Systems in Secondary School Classrooms: A Formative Analysis

    ERIC Educational Resources Information Center

    Kay, Robin; LeSage, Ann; Knaack, Liesel

    2010-01-01

    To date, extensive research has been done on the use of Audience Response Systems (ARSs) in colleges and universities, but not in secondary school schools. The purpose of this study was to conduct a detailed formative analysis on the benefits, challenges, and use of ARSs from the perspective of 659 secondary school students. Key benefits reported…

  20. Formative Assessment in the Grenadian Lower Secondary School: Teachers' Perceptions, Attitudes and Practices

    ERIC Educational Resources Information Center

    Young, James E. J.; Jackman, Mary Grace-Anne

    2014-01-01

    The purpose of this study was to explore the perceptions, attitudes and frequency of use of formative assessment strategies of teachers in the Grenadian lower secondary school (Forms 1, 2 and 3). The study, which was quantitative in nature, involved 252 lower secondary school teachers. Overall the participants had positive perceptions and…

  1. Organic Aerosol Formation Photoenhanced by the Formation of Secondary Photo-sensitizers in ageing Aerosols

    NASA Astrophysics Data System (ADS)

    Aregahegn, Kifle; Nozière, Barbara; George, Christian

    2013-04-01

    Humankind is facing a changing environment possibly due to anthropogenic stress on the atmosphere. In this context, aerosols play a key role by affecting the radiative climate forcing, hydrological cycle, and by their adverse effect on health. The role of organic compounds in these processes is however still poorly understood because of their massive chemical complexity and numerous transformations. This is particularly true for Secondary Organic Aerosol (SOA), which are produced in the atmosphere by organic gases. Traditionally, the driving forces for SOA growth is believed to be the partitioning onto aerosol seeds of condensable gases, either emitted primarily or resulting from the gas phase oxidation of organic gases. However, even the most up-to-date models based on such mechanisms can not account for the SOA mass observed in the atmosphere, suggesting the existence of other, yet unknown formation processes. The present study shows experimental evidence that particulate phase chemistry produces photo-sensitizers that lead to photo-induced formation and growth of secondary organic aerosol in the near UV and the presence of volatile organic compounds (VOC) such as terpenes. By means of an aerosol flow tube reactor equipped with Scanning Mobility Particle Sizer (SMPS) having Kr-85 source aerosol neutralizer, Differential Mobility Analyser (DMA) and Condensation Particle Sizer (CPC), we identified that traces of the aerosol phase product of glyoxal chemistry as is explained in Gallway et al., and Yu et al., namely imidazole-2-carboxaldehyde (IC) is a strong photo-sensitizer when irradiated by near-UV in the presence of volatile organic compounds such as terpenes. Furthermore, the influence of pH, type and concentration of VOCs, composition of seed particles, relative humidity and irradiation intensity on particle growth were studied. This novel photo-sensitizer contributed to more than 30% of SOA growth in 19min irradiation time in the presence of terpenes in the

  2. Role of particulate metals in heterogenous secondary sulfate formation

    NASA Astrophysics Data System (ADS)

    Clements, Andrea L.; Buzcu-Guven, Birnur; Fraser, Matthew P.; Kulkarni, Pranav; Chellam, Shankararaman

    2013-08-01

    A series of field sampling and controlled laboratory experiments were undertaken to quantify the role of trace metals found in ambient fine particulate matter and metal-rich primary sources in the heterogenous catalytic conversion of SO2 gas into sulfate particulate matter (PM) in the atmosphere. Analysis produced source profiles of three primary source materials, fluidized-bed catalytic cracking catalyst, coal-fired combustion fly ash, and paved road dust, featuring 33 elements including rare earth metals, which are not commonly reported in the literature. Subsequently three sets of experiments were conducted exposing 1) source materials, 2) ambient PM, and 3) ambient PM augmented with approximately an equal amount of source material to SO2 gas and measuring sulfate formation. Source material experiments revealed that the greatest extent of reaction was on the surface of coal fly ash with sulfate formation of 19 ± 5 mg sulfate g-1 material. Ambient fine particulate matter (PM) experiments showed sulfate formation ranging from negligible amounts to 180 ± 10 mg sulfate g-1 PM. It was much more difficult to quantify the sulfate formation on ambient filters augmented with the source materials. In these experiments, sulfate formation ranged from negligible amounts to 40 ± 8 mg sulfate g-1 of particles (ambient + augmented material). These three sets of experiments shows that heterogenous sulfate formation is often negligible but, under some conditions can contribute 10% or more to the total sulfate concentrations when exposed to high SO2 concentrations such as those found in plumes. Factor analysis of the source material experiments grouped metals into two categories, crustal components and anthropogenically emitted metals representative of catalyst material, with the former showing the strongest correlation with sulfate formation. Subsequent analysis of data collected from the ambient PM experiments showed a much weaker correlation of sulfate formation with the

  3. Ultrasound-Guided Glue Injection as Alternative Treatment of Femoral Pseudoaneurysms

    SciTech Connect

    Aytekin, Cueneyt; Firat, Ali; Yildirim, Erkan; Kirbas, Ismail; Boyvat, Fatih

    2004-11-15

    The interventional angiographic techniques using the percutaneous femoral approach for endovascular revascularization are becoming increasingly more popular. These methods usually require larger sheaths, and most patients need postprocedural anticoagulation or antiplatelet therapy. As a consequence, the interventional procedure is associated with a higher rate of complications at the arterial entry site compared to diagnostic angiography. The reported incidence of iatrogenic pseudoaneurysm formation after coronary artery interventions ranges from 3.2% to 7.7%, and the rates noted after diagnostic angiography range from 0.2% to 1%. Peripheral pseudoaneurysms have traditionally been treated by surgical intervention, but nonsurgical alternatives, such as ultrasound (US)-guided compression, coil embolization, stent-graft placement, and percutaneous thrombin injection with or without balloon occlusion have also been documented. Of these alternatives, direct percutaneous embolization with embolic agents is the most popular method. The tissue adhesive n-butyl cyanoacrylate (NBCA) (Hystoacryl) (B. Braun, Melsungen, Germany) is one of the most popular occluding agents for neurovascular interventions, and has been widely used for more than 20 years [5,6]. In this study, we evaluated the efficacy and utility of direct percutaneous injection of NBCA for embolization of femoral pseudoaneurysms.

  4. Formation potential of nine nitrosamines from corresponding secondary amines by chloramination.

    PubMed

    Zhou, Wenjun; Chen, Cuiping; Lou, Linjie; Yang, Qi; Zhu, Lizhong

    2014-01-01

    Nitrosamines, a group of emerging disinfection by-products (DBPs) in drinking water, have recently caused significant concern because of their higher carcinogenic potential than that of currently regulated DBPs. In this study, the formation of nine representative nitrosamines by chloramination of their corresponding secondary amines was investigated under various conditions. All nine nitrosamines were detected in the corresponding reaction solutions, which confirmed that all the investigated secondary amines were the potential precursors of corresponding nitrosamines. The molar yields of nitrosamines from the corresponding secondary amines were quite different, depending on the structural characteristics of the secondary amines. The maximum molar yields for the formation of all nine nitrosamines occurred in the pH range of 7.0-9.0 and at the Cl/N molar ratio of 0.7 for chloramines, suggesting that monochloramine and unprotonated secondary amines may play a major role in the formation of nitrosamines. The molar yields of nitrosamines also exhibited a moderate upward tendency with rising temperature, but no consistent correlation was observed between the formation of nitrosamine and the initial concentrations of secondary amines and chloramines. The results of this study could be useful for devising strategies for controlling the formation of nitrosamines during the disinfection processes of drinking water.

  5. Influence of Aerosol Acidity on the Formation of Secondary Organic Aerosol from Biogenic Precursor Hydrocarbons

    EPA Science Inventory

    Secondary organic aerosol (SOA) formation and dynamics may be important factors for the role of aerosols in adverse health effects, visibility and climate change. Formation of SOA occurs when a parent volatile organic compound is oxidized to create products that form in a conden...

  6. Alternative Format Preferences among Secondary School Visually Impaired Students in Nigeria

    ERIC Educational Resources Information Center

    Adetoro, 'Niran

    2012-01-01

    Persons with visual impairment have consistently shown a preference for one alternative reading format over another, often because of factors outside their control. This study adopted survey research design to investigate alternative format preferences among secondary school visually impaired students, focusing on Southwestern Nigeria. Using total…

  7. Early Stent Graft Perforation after Endovascular Repair for Pseudoaneurysm That Was Associated with Clavicle Nonunion

    PubMed Central

    Touma, Masanao; Ohno, Nobuhisa; Yoshikawa, Eiji; Yoshizawa, Kousuke; Fujiwara, Keiichi

    2015-01-01

    We report the case of a 62-year-old man who experienced a left axillary artery pseudoaneurysm that was secondary to nonunion of a 30-year-old left midshaft clavicle fracture. He initially underwent endovascular repair using a self-expanding nitinol stent graft, which was perforated at postoperative day 5. Therefore, we performed open repair with concomitant clavicle resection, and no complications were observed during an approximately 6-year follow-up. We recommend performing clavicle resection with vascular repair to prevent recurrence in similar cases. PMID:26421082

  8. Gastroduodenal artery pseudoaneurysm ruptured in the common bile duct.

    PubMed

    Fodor, M; Fodor, L; Ciuce, C

    2010-01-01

    A pseudoaneurysm of the gastroduodenal artery (GDA) is the rarest splanchnic artery aneurysm, comprising fewer than 10% of these lesions. Bleeding into the gastrointestinal tract is the most rapidly fatal complication of an arterial visceral pseudoaneurysm, affecting 4-10% of patients. We present an unusual case of a GDA pseudoaneurysm that ruptured in the common bile duct, and that was successfully treated by partial resection and hepatic artery reconstruction. The postoperative evolution was favourable and the CT performed six months later disclosed the absence of a vascular tumour.

  9. A bulbar artery pseudoaneurysm following traumatic urethral catheterization

    PubMed Central

    Bettez, Mathieu; Aubé, Melanie; Sherbiny, Mohamed El; Cabrera, Tatiana; Jednak, Roman

    2017-01-01

    Traumatic urethral catheterization may result in a number of serious complications. A rare occurrence is the development of a urethral pseudoaneurysm. We report the case of a 13-year-old male who required placement of a Foley catheter for an orthopedic surgical procedure. The Foley was misplaced in the bulbourethra, resulting in the development of a bulbar artery pseudoaneurysm. Profuse bleeding via the urethra was noted after removal of the catheter, and the patient experienced severe intermittent hematuria during the postoperative period. Cystoscopy revealed a pulsatile mass within the bulbourethra. Angiography confirmed a bulbar artery pseudoaneurysm, which was successfully embolized with resolution of bleeding. PMID:28163815

  10. Endovascular Treatment of Two Pseudoaneurysms Originating From the Left Ventricle

    SciTech Connect

    Cwikiel, Wojciech Keussen, Inger; Gustafsson, Ronny; Mokhtari, Arash

    2013-12-15

    A 67-year-old woman resented with an acute type A aortic dissection, which was treated surgically with aortic valve replacement as a composite graft with reimplantation of the coronary arteries. At the end of surgery, a left-ventricular venting catheter was placed through the apex and closed with a buffered suture. Consecutive computed tomography (CT) examinations verified a growing apex pseudoaneurysm. Communication between the ventricle and the pseudoaneurysm was successfully closed with an Amplatz septal plug by the transfemoral route. Follow-up CT showed an additional pseudoaneurysm, which also was successfully closed using the same method.

  11. Secondary organic aerosol formation from the irradiation of simulated automobile exhaust.

    PubMed

    Kleindienst, T E; Corse, E W; Li, W; McIver, C D; Conver, T S; Edney, E O; Driscoll, D J; Speer, R E; Weathers, W S; Tejada, S B

    2002-03-01

    A laboratory study was conducted to evaluate the potential for secondary organic aerosol formation from emissions from automotive exhaust. The goal was to determine to what extent photochemical oxidation products of these hydrocarbons contribute to secondary organic aerosol (SOA) and how well their formation is described by recently developed models for SOA formation. The quality of a surrogate was tested by comparing its reactivity with that from irradiations of authentic automobile exhaust. Experiments for secondary particle formation using the surrogate were conducted in a fixed volume reactor operated in a dynamic mode. The mass concentration of the aerosol was determined from measurements of organic carbon collected on quartz filters and was corrected for the presence of hydrogen, nitrogen, and oxygen atoms in the organic species. A functional group analysis of the aerosol made by Fourier transform infrared (FTIR) spectroscopy indicated

  12. Fuel composition and secondary organic aerosol formation: gas-turbine exhaust and alternative aviation fuels.

    PubMed

    Miracolo, Marissa A; Drozd, Greg T; Jathar, Shantanu H; Presto, Albert A; Lipsky, Eric M; Corporan, Edwin; Robinson, Allen L

    2012-08-07

    A series of smog chamber experiments were performed to investigate the effects of fuel composition on secondary particulate matter (PM) formation from dilute exhaust from a T63 gas-turbine engine. Tests were performed at idle and cruise loads with the engine fueled on conventional military jet fuel (JP-8), Fischer-Tropsch synthetic jet fuel (FT), and a 50/50 blend of the two fuels. Emissions were sampled into a portable smog chamber and exposed to sunlight or artificial UV light to initiate photo-oxidation. Similar to previous studies, neat FT fuel and a 50/50 FT/JP-8 blend reduced the primary particulate matter emissions compared to neat JP-8. After only one hour of photo-oxidation at typical atmospheric OH levels, the secondary PM production in dilute exhaust exceeded primary PM emissions, except when operating the engine at high load on FT fuel. Therefore, accounting for secondary PM production should be considered when assessing the contribution of gas-turbine engine emissions to ambient PM levels. FT fuel substantially reduced secondary PM formation in dilute exhaust compared to neat JP-8 at both idle and cruise loads. At idle load, the secondary PM formation was reduced by a factor of 20 with the use of neat FT fuel, and a factor of 2 with the use of the blend fuel. At cruise load, the use of FT fuel resulted in no measured formation of secondary PM. In every experiment, the secondary PM was dominated by organics with minor contributions from sulfate when the engine was operated on JP-8 fuel. At both loads, FT fuel produces less secondary organic aerosol than JP-8 because of differences in the composition of the fuels and the resultant emissions. This work indicates that fuel reformulation may be a viable strategy to reduce the contribution of emissions from combustion systems to secondary organic aerosol production and ultimately ambient PM levels.

  13. Nonequilibrium Atmospheric Secondary Organic Aerosol Formation and Growth

    SciTech Connect

    Perraud, Veronique M.; Bruns, Emily A.; Ezell, Michael J.; Johnson, Stanley N.; Yu, Yong; Alexander, M. L.; Zelenyuk, Alla; Imre, D.; Chang, W. L.; Dabdub, Donald; Pankow, James F.; Finlayson-Pitts, Barbara J.

    2012-02-21

    Airborne particles play a critical role in air quality, human health effects, visibility and climate. Secondary organic aerosols (SOA) account for a significant portion of total airborne particles. They are formed in reactions of organic gases that produce low volatility and semi-volatile organic compounds (SVOCs). Current atmospheric models assume that SOA are liquids into which SVOCs undergo equilibrium partitioning and grow the particles. However a large discrepancy between model predictions and field measurements of SOA is commonly observed. We report here laboratory studies of the oxidation of a-pinene by ozone and nitrate radicals and show that particle composition is actually consistent with a kinetically determined growth mechanism, and not with equilibrium partitioning between the gas phase and liquid particles. If this is indeed a general phenomenon in air, the formulation of atmospheric SOA models will have to be revised to reflect this new paradigm. This will have significant impacts on quantifying the role of SOA in air quality, visibility, and climate.

  14. Secondary Aerosol: Precursors and Formation Mechanisms. Technical Report on Grant

    SciTech Connect

    Weinstein-Lloyd, Judith B

    2009-05-04

    This project focused on studying trace gases that participate in chemical reactions that form atmospheric aerosols. Ammonium sulfate is a major constituent of these tiny particles, and one important pathway to sulfate formation is oxidation of dissolved sulfur dioxide by hydrogen peroxide in cloud, fog and rainwater. Sulfate aerosols influence the number and size of cloud droplets, and since these factors determine cloud radiative properties, sulfate aerosols also influence climate. Peroxide measurements, in conjunction with those of other gaseous species, can used to distinguish the contribution of in-cloud reaction to new sulfate aerosol formation from gas-phase nucleation reactions. This will lead to more reliable global climate models. We constructed and tested a new 4-channel fluorescence detector for airborne detection of peroxides. We integrated the instrument on the G-1 in January, 2006 and took a test flight in anticipation of the MAX-Mex field program, where we planned to fly under pressurized conditions for the first time. We participated in the 2006 Megacity Initiative: Local and Global Research Observations (MILAGRO) - Megacity Aerosol EXperiment Mexico City (MAX-Mex) field measurement campaign. Peroxide instrumentation was deployed on the DOE G-1 research aircraft based in Veracruz, and at the surface site at Tecamac University.

  15. Lumbar spine osteomyelitis and epidural abscess formation secondary to acupuncture

    PubMed Central

    Godhania, Vinesh

    2016-01-01

    A 39-year-old male with no previous medical history presented with abdominal and low back pain. Based on clinical and radiological findings he was diagnosed with L1/L2 osteomyelitis and epidural abscess. Further history taking revealed recent use of acupuncture for treatment of mechanical back pain. The patient was treated conservatively with an extended course of antibiotics, monitored with repeat MRI scans and had a full recovery with no neurological deficit. This is the first reported case of epidural abscess formation and osteomyelitis after acupuncture in the UK. As acupuncture becomes more commonly used in western countries, it is important to be aware of this rare but serious complication. PMID:26976275

  16. Cerebrovascular bypass and aneurysm trapping for the treatment of an A2-segment anterior cerebral artery pseudoaneurysm and herniation through a skull base defect following trauma.

    PubMed

    Walcott, Brian P; Nahed, Brian V; Kahle, Kristopher T; Sekhar, Laligam N; Ferreira, Manuel J

    2012-01-01

    Fractures of the anterior skull base can lead to pseudoaneurysm formation as a result of direct injury to a vessel wall. Pseudoaneurysms in this location are challenging to treat, as both perforator and distal blood supply must be maintained. Additionally, traumatic skull base fractures can lead to a rare condition of cerebral blood vessel herniation through the bony defect, further complicating treatment planning. Treatment of these lesions is essential to (1) prevent the occurrence of potentially fatal subarachnoid hemorrhage and (2) prevent dissection from propagating and compromising blood flow to distal vessels, perforators, and even parent vessels. We present a unique case of a traumatic proximal anterior cerebral artery pseudoaneurysm, herniating through a skull base defect. Treatment consisted of aneurysm trapping and bypass with skull base reconstruction.

  17. Endovascular Management of Superior Mesenteric Artery Pseudoaneurysm and Fistula

    SciTech Connect

    Narayanan, Govindarajan; Barbery, Katuska; Lamus, Daniel; Nanavati, Kunal

    2008-11-15

    The uncommon presentation of an arterioportal fistula (APF) involving the superior mesenteric artery (SMA) associated with a pseudoaneurysm represents a therapeutic challenge. We present the case of a 24-year-old female admitted to the hospital after multiple gunshot wounds to the abdomen; the patient underwent multiple surgeries and, in the process, developed a SMA pseudoaneurysm and fistula. The vascular interventional radiology team was consulted for treatment of the pseudoaneurysm and fistula. A covered stent was inserted percutaneously to exclude the APF and the pseudoaneurysm in a single procedure. The patient returned to our service after 21 months for a follow-up CT scan, which demonstrated the stent and the distal vasculature to be patent.

  18. Endovascular Management of an Infected Superficial Femoral Artery Pseudoaneurysm

    SciTech Connect

    Damodharan, Karthik Beckett, David

    2013-10-15

    This article describes an endovascular technique of treating an infected pseudoaneurysm by direct thrombin injection via a catheter placed inside the aneurysm sac while maintaining temporary balloon occlusion of the neck of the false aneurysm.

  19. Laparoscopic management of post-cholecystectomy sectoral artery pseudoaneurysm

    PubMed Central

    Panda, Nilanjan; Narasimhan, Mohan; Gunaraj, Alwin; Ardhanari, Ramesh

    2014-01-01

    Vascular injuries during laparoscopic cholecystectomy can occur similar to biliary injuries and mostly represented by intraoperative bleeding. Hepatic artery system pseudoaneurysm are rare. It occurs in the early or late postoperative course. Patients present with pallor, signs of haemobillia and altered liver function. We report a case of right posterior sectoral artery pseudoaneurysm detected 2 weeks after laparoscopic cholecystectomy and successfully repaired laparoscopically. We also describe how laparoscopic pringle clamping saved the conversion. The actively bleeding right posterior sectoral artery pseudoaneurysm was diagnosed by CT angiogram. Embolisation, usually the treatment of choice, would have risked liver insufficiency as hepatic artery proper was at risk because the origin the bleeding artery was just after its bifurcation. Isolated right hepatic artery embolisation can also cause hepatic insufficiency. To our knowledge this is the first reported case of laparoscopic repair of post-laparoscopic cholecystectomy bleeding sectoral artery pseudoaneurysm. PMID:24501508

  20. Emergency Stenting of a Ruptured Infected Anastomotic Femoral Pseudoaneurysm

    SciTech Connect

    Klonaris, Chris Katsargyris, Athanasios; Matthaiou, Alexandros; Giannopoulos, Athanasios; Tsigris, Chris; Papadopouli, Katerina; Tsiodras, Sotiris; Bastounis, Elias

    2007-11-15

    A 74-year-old man presented with a ruptured infected anastomotic femoral pseudoaneurysm. Due to severe medical comorbidities he was considered unsuitable for conventional surgical management and underwent an emergency endovascular repair with a balloon-expandable covered stent. The pseudoaneurysm was excluded successfully and the patient had an uneventful postoperative recovery with long-term suppressive antimicrobials. He remained well for 10 months after the procedure with no signs of recurrent local or systemic infection and finally died from an acute myocardial infarction. To our knowledge, emergency endovascular treatment of a free ruptured bleeding femoral artery pseudoaneurysm has not been documented before in the English literature. This case illustrates that endovascular therapy may be a safe and efficient alternative in the emergent management of ruptured infected anastomotic femoral artery pseudoaneurysms when traditional open surgery is contraindicated.

  1. Concomitant Lumbar Stenosis and Aortic Pseudoaneurysm: A Case Report

    PubMed Central

    Fuchs, Christoph; Niemeier, Thomas E; Neway, William E

    2016-01-01

    Aortic pseudoaneurysm can create a constellation of symptoms that can mimic lumbar back pain. There are rare but well-documented reports of aortic pathology (aneurysms, pseudoaneurysms, and chronic contained aneurysm ruptures) eroding into the vertebral column causing neural compression. We report a case of a rapidly progressive aortic pseudoaneurysm in a patient with pre-existing lumbar spine pathology which had the potential for catastrophic intraoperative bleeding during a minimally invasive surgery (MIS) using the transforaminal lumbar interbody fusion (TLIF) technique. Postoperatively, the patient’s radicular pain resolved but her back pain remained. Further workup identified the pseudoaneurysm and the patient subsequently underwent open vascular repair. In this report, we highlight a lesser known mimicker of lumbar back pain. PMID:27882269

  2. Two Cases of Postmyomectomy Pseudoaneurysm Treated by Transarterial Embolization

    SciTech Connect

    Ito, Nobutake; Natimatsu, Yoshiaki; Tsukada, Jitsuro; Sato, Akihiro; Hasegawa, Ichiro; Lin, Bao-Liang

    2013-12-15

    Pseudoaneurysm resulting from hysteroscopic myomectomy is a rare clinical situation, and interventional radiologists are not traditionally involved in the management. To our knowledge, endovascular treatment of a pseudoaneurysm resulting from hysteroscopic myomectomy has not yet been reported in the English-language literature. Here, two such cases are reported, including one of a woman who later became pregnant. The case is unique because little is known about the influence of unilateral coil embolization of the uterine artery on fertility.

  3. Secondary island formation in collisional and collisionless kinetic simulations of magnetic reconnection

    SciTech Connect

    Dayton, William S; Roytershteyn, Vadim; Gary, Peter; Yin, L; Albright, B J; Bowers, K J; Karimabadi, H

    2009-01-01

    The evolution of magnetic reconnection in large-scale systems often gives rise to extended current layers that are unstable to the formation of secondary magnetic islands. The role of these islands in the reconnection process and the conditions under which they form remains a subject of debate. In this work, we benchmark two different kinetic particle-in-cell codes to address the formation of secondary islands for several types of global boundary conditions. The influence on reconnection is examined for a range of conditions and collisionality limits. Although secondary islands are observed in all cases, their influence on reconnection may be different depending on the regime. In the collisional limit, the secondary islands playa key role in breaking away from the Sweet-Parker scaling and enabling faster reconnection. In the collisionless limit, their formation is one mechanism for controlling the length of the diffusion region. In both limits, the onset of secondary islands leads to a time dependent behavior in the reconnection rate. In all cases considered, the number of secondary islands increases for larger systems.

  4. Progressive paralyzing sciatica revealing a pelvic pseudoaneurysm a year after hip surgery in a 12yo boy.

    PubMed

    Boulouis, Grégoire; Shotar, Eimad; Dangouloff-Ros, Volodia; Janklevicz, Pierre-Henri; Boddaert, Nathalie; Naggara, Olivier; Brunelle, Francis

    2016-01-01

    Identifying extra spinal causes of a lumbar radiculopathy or polyneuropathy can be a tricky diagnosis challenge, especially in children. Among them, traumatic or iatrogenic pseudoaneurysms of iliac arteries have been seldom reported, in adults' series. The authors report an unusual case of progressive paralyzing left sciatica and lumbar plexopathy in a 12 years old boy, 12 months after a pelvic osteotomy for bilateral hip luxation secondary to osteochondritis dissecans. Spine MRI and pelvic CT angiography revealed a giant internal iliac artery pseudoaneurysm, enclosed in a chronic hematoma. The patient was successfully treated with endovascular coil embolization, and subsequent surgical hematoma evacuation. However, three months after treatment, neurological recovery was incomplete. This case highlights the importance of a rapid and extensive diagnosis work up of all causes of lower limb radiculopathies in children, including pelvic arteries lesions especially after pelvic surgery to avoid therapeutic delays that may jeopardize the chances of neurological recovery.

  5. Endovascular Management of Iatrogenic Native Renal Arterial Pseudoaneurysms

    SciTech Connect

    Sildiroglu, Onur; Saad, Wael E.; Hagspiel, Klaus D.; Matsumoto, Alan H.; Turba, Ulku Cenk

    2012-12-15

    Purpose: Our purpose was to evaluate iatrogenic renal pseudoaneurysms, endovascular treatment, and outcomes. Methods: This retrospective study (2003-2011) reported the technical and clinical outcomes of endovascular therapy for renal pseudoaneurysms in eight patients (mean age, 46 (range 24-68) years). Renal parenchymal loss evaluation was based on digital subtraction angiography and computed tomography. Results: We identified eight iatrogenic renal pseudoaneurysm patients with symptoms of hematuria, pain, and hematoma after renal biopsy (n = 3), surgery (n = 3), percutaneous nephrolithotomy (n = 1), and endoscopic shock-wave lithotripsy (n = 1). In six patients, the pseudoaneurysms were small-sized (<20 mm) and peripherally located and were treated solely with coil embolization (n = 5). In one patient, coil embolization was preceded by embolization with 500-700 micron embospheres to control active bleeding. The remaining two patients had large-sized ({>=}50 mm), centrally located renal pseudoaneurysms treated with thrombin {+-} coils. Technical success with immediate bleeding cessation was achieved in all patients. There were no procedure-related deaths or complications (mean follow-up, 23.5 (range, 1-67) months). Conclusions: Treatment of renal pseudoaneurysms using endovascular approach is a relatively safe and viable option regardless of location (central or peripheral) and size of the lesions with minimal renal parenchymal sacrifice.

  6. Endovascular Treatment for Proximal Anastomotic Pseudoaneurysm after Total Arch Replacement in Behcet's Disease.

    PubMed

    Sakata, Tomoki; Ueda, Hideki; Watanabe, Michiko; Kohno, Hiroki; Tamura, Yusaku; Abe, Shinichiro; Inage, Yuichi; Ikeuchi, Hiroki; Kanda, Tomoyoshi; Fujii, Masahiko; Matsumiya, Goro

    2016-07-01

    A 17-year-old patient underwent total arch replacement for aortic arch aneurysm due to vascular Behcet's disease (BD). Follow-up computed tomography, performed 6 months after the operation, demonstrated pseudoaneurysm formation at the proximal anastomotic site. We performed endovascular treatment and used a short stent graft that was originally designed for abdominal aortic aneurysm. To avoid the occlusion of the coronary or brachiocephalic artery (BCA) due to stent graft migration, we used right ventricular rapid pacing and BCA ballooning. Thus, we believe that endovascular treatment can be used for anastomotic complications in the ascending aorta after open surgery for connective tissue disorders including BD.

  7. Endovascular Treatment of an Aortoiliac Tuberculous Pseudoaneurysm

    SciTech Connect

    Villegas, Miguel O.; Mereles, Alberto Perez; Tamashiro, Gustavo A.; Dini, Andres E.; Mollon, Ana P.; De Candido, Laura V.; Zelaya, Denis A.; Soledispa-Suarez, Carlos I.; Denato, Sergio; Tamashiro, Alberto; Diaz, Jose A.

    2013-04-15

    We report a rare case of a tuberculous mycotic aortoiliac pseudoaneurysm treated with an endovascular procedure and follow-up of 36 months. The patient was a white 72-year-old man with pulmonary tuberculosis and a former smoker with hypertension, chronic renal failure, and dyslipidemia. A computed tomographic scan of the abdomen and pelvis revealed a left paravertebral cavity with fluid content and involvement of vertebrae L2-L4. After a surgical repair attempt, the patient was treated with the implant of a bifurcated endoprosthesis. Because it is unlikely that any center has extensive experience in the management of this rare manifestation of the disease, we reviewed the literature for similar cases.

  8. Formation of Secondary Particulate Matter by Reactions of Gas Phase Hexanal with Sulfate Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2003-12-01

    The formation of secondary particulate matter from the atmospheric oxidation of organic compounds can significantly contribute to the particulate burden, but the formation of organic secondary particulate matter is poorly understood. One way of producing organic secondary particulate matter is the oxidation of hydrocarbons with seven or more carbon atoms to get products with low vapor pressure. However, several recent reports suggest that relatively low molecular weight carbonyls can enter the particle phase by undergoing heterogeneous reactions. This may be a very important mechanism for the formation of organic secondary particulate matter. Atmospheric aldehydes are important carbonyls in the gas phase, which form via the oxidation of hydrocarbons emitted from anthropogenic and biogenic sources. In this poster, we report the results on particle growth by the heterogeneous reactions of hexanal. A 5 L Continuous Stirred Tank Reactor (CSTR) is set up to conduct the reactions in the presence of seed aerosol particles of deliquesced ammonia bisulfate. Hexanal is added into CSTR by syringe pump, meanwhile the concentrations of hexanal are monitored with High Pressure Liquid Chromatograph (HPLC 1050). A differential Mobility Analyzer (TSI 3071) set to an appropriate voltage is employed to obtain monodisperse aerosols, and another DMA associated with a Condensation Nuclear Counter (TSI 7610) is used to measure the secondary particle size distribution by the reaction in CSTR. This permits the sensitive determination of particle growth due to the heterogeneous reaction, very little growth occurs when hexanal added alone. Results for the simultaneous addition of hexanal and alcohols will also be presented.

  9. Formative Assessment and Increased Student Involvement Increase Grades in an Upper Secondary School Biology Course

    ERIC Educational Resources Information Center

    Granbom, Martin

    2016-01-01

    This study shows that formative methods and increased student participation has a positive influence on learning measured as grades. The study was conducted during the course Biology A in a Swedish Upper Secondary School. The students constructed grade criteria and defined working methods and type of examination within a given topic, Gene…

  10. Public Health Impacts of Secondary Particulate Formation from Aromatic Hydrocarbons in Gasoline

    EPA Science Inventory

    Background: Aromatic hydrocarbons emitted from gasoline‐powered vehicles contribute to the formation of secondary organic aerosol (SOA), which increases the atmospheric mass concentration of fine particles (PM2.5). Here we estimate the public health burden associated w...

  11. Secondary organic aerosol formation from reaction of tertiary amines with nitrate radical

    NASA Astrophysics Data System (ADS)

    Erupe, M. E.; Price, D. J.; Silva, P. J.; Malloy, Q. G. J.; Qi, L.; Warren, B.; Cocker, D. R., III

    2008-09-01

    Secondary organic aerosol formation from the reaction of tertiary amines with nitrate radical was investigated in an indoor environmental chamber. Particle chemistry was monitored using a high resolution aerosol mass spectrometer while gas-phase species were detected using a proton transfer reaction mass spectrometer. Trimethylamine, triethylamine and tributylamine were studied. Results indicate that tributylamine forms the most aerosol mass followed by trimethylamine and triethylamine respectively. Spectra from the aerosol mass spectrometer indicate the formation of complex non-salt aerosol products. We propose a reaction mechanism that proceeds via abstraction of a proton by nitrate radical followed by RO2 chemistry. Rearrangement of the aminyl alkoxy radical through hydrogen shift leads to the formation of hydroxylated amides, which explain most of the higher mass ions in the mass spectra. These experiments show that oxidation of tertiary amines by nitrate radical may be an important night-time source of secondary organic aerosol.

  12. A rare case of splenic pseudoaneurysm in pediatric splenic blunt trauma patient: Review of diagnosis and management

    PubMed Central

    Zhu, Roger Chen; Kurbatov, Vadim; Leung, Patricia; Sugiyama, Gainosuke; Roudnitsky, Valery

    2015-01-01

    Introduction Splenic pseudoaneurysms (SPA) are a rare but serious sequela of blunt traumatic injury to the spleen. Management of adult blunt splenic trauma is well-studied, however, in children, the management is much less well-defined. Presentation of case A 15 year-old male presented with severe abdominal pain of acute onset after sustaining injury to his left side while playing football. FAST was positive for free fluid in the abdomen. Initial abdomen CT demonstrated a grade III/IV left splenic laceration with moderate to large hemoperitoneum with no active extravasation or injury to the splenic vessels noted. A follow-up CT angiography of the abdomen demonstrated a splenic hypervascular structure suspicious for a small pseudoaneurysm. Splenic arteriogram which demonstrated multiple pseudoaneurysms arising from the second order splenic artery branches which was angioembolized and treated. Discussion & conclusion Questions still remain regarding the timing of repeat imaging for diagnosis of SPA following non-operative blunt splenic trauma, which patients should be imaged, and how to manage SPA upon diagnosis. More clinical study and basic science research is warranted to study the disease process of SPA in pediatric patient. We believe that our proposed management algorithm timely detect formation of delayed SPA formation and addresses the possible fatal disease course of pediatric SPA. PMID:26117449

  13. Synergetic formation of secondary inorganic and organic aerosol: effect of SO2 and NH3 on particle formation and growth

    NASA Astrophysics Data System (ADS)

    Chu, Biwu; Zhang, Xiao; Liu, Yongchun; He, Hong; Sun, Yele; Jiang, Jingkun; Li, Junhua; Hao, Jiming

    2016-11-01

    The effects of SO2 and NH3 on secondary organic aerosol formation have rarely been investigated together, while the interactive effects between inorganic and organic species under highly complex pollution conditions remain uncertain. Here we studied the effects of SO2 and NH3 on secondary aerosol formation in the photooxidation system of toluene/NOx in the presence or absence of Al2O3 seed aerosols in a 2 m3 smog chamber. The presence of SO2 increased new particle formation and particle growth significantly, regardless of whether NH3 was present. Sulfate, organic aerosol, nitrate, and ammonium were all found to increase linearly with increasing SO2 concentrations. The increases in these four species were more obvious under NH3-rich conditions, and the generation of nitrate, ammonium, and organic aerosol increased more significantly than sulfate with respect to SO2 concentration, while sulfate was the most sensitive species under NH3-poor conditions. The synergistic effects between SO2 and NH3 in the heterogeneous process contributed greatly to secondary aerosol formation. Specifically, the generation of NH4NO3 was found to be highly dependent on the surface area concentration of suspended particles, and increased most significantly with SO2 concentration among the four species under NH3-rich conditions. Meanwhile, the absorbed NH3 might provide a liquid surface layer for the absorption and subsequent reaction of SO2 and organic products and, therefore, enhance sulfate and secondary organic aerosol (SOA) formation. This effect mainly occurred in the heterogeneous process and resulted in a significantly higher growth rate of seed aerosols compared to without NH3. By applying positive matrix factorisation (PMF) analysis to the AMS data, two factors were identified for the generated SOA. One factor, assigned to less-oxidised organic aerosol and some oligomers, increased with increasing SO2 under NH3-poor conditions, mainly due to the well-known acid catalytic effect of

  14. Secondary Organic Aerosol Formation from the Photooxidation of p- and o-Xylene

    SciTech Connect

    Song, Chen; Na, Kwangsam; Warren, Bethany; Malloy, Quentin; Cocker, David R.

    2007-11-01

    The formation of secondary organic aerosol (SOA) from the photooxidation of xylene isomers (m-, p-, and o-xylenes) has been extensively investigated. The dependence of SOA aerosol formation on the structure of xylene isomers in the presence of NO was confirmed. Generally, SOA formation of p-xylene was less than that ofm- and o-xylenes. This discrepancy varies significantly with initial NOx levels. In a NOx-free environment, the difference of aerosol formation between o- and p-xylenes becomes insignificant. Several chemical pathways for the SOA dependence on structure and NOx are explored, with the experimental findings indicating that organic peroxides may be a major key to explaining SOA formation from aromatic hydrocarbons.

  15. Increasing Gas Hydrate Formation Temperature for Desalination of High Salinity Produced Water with Secondary Guests

    SciTech Connect

    Cha, Jong-Ho; Seol, Yongkoo

    2013-10-07

    We suggest a new gas hydrate-based desalination process using water-immiscible hydrate formers; cyclopentane (CP) and cyclohexane (CH) as secondary hydrate guests to alleviate temperature requirements for hydrate formation. The hydrate formation reactions were carried out in an isobaric condition of 3.1 MPa to find the upper temperature limit of CO2 hydrate formation. Simulated produced water (8.95 wt % salinity) mixed with the hydrate formers shows an increased upper temperature limit from -2 °C for simple CO2 hydrate to 16 and 7 °C for double (CO2 + CP) and (CO2 + CH) hydrates, respectively. The resulting conversion rate to double hydrate turned out to be similar to that with simple CO2 hydrate at the upper temperature limit. Hydrate formation rates (Rf) for the double hydrates with CP and CH are shown to be 22 and 16 times higher, respectively, than that of the simple CO2 hydrate at the upper temperature limit. Such mild hydrate formation temperature and fast formation kinetics indicate increased energy efficiency of the double hydrate system for the desalination process. Dissociated water from the hydrates shows greater than 90% salt removal efficiency for the hydrates with the secondary guests, which is also improved from about 70% salt removal efficiency for the simple hydrates.

  16. Successful Post-Pancreatitis Pseudoaneurysm Coagulation by Percutaneous Computed Tomography (CT)-Guided Thrombin Injection

    PubMed Central

    Spezia, Laura; Sozzi, Carlo; Contro, Alberto; Mansueto, Giancarlo

    2017-01-01

    Summary Background Pseudoaneurysm is a rare but potentially life-threatening vascular complication of acute pancreatitis, with a mortality rate of 20–43% in untreated patients. The treatment usually involves trans-arterial embolization or surgical resection. Case Report A 44-year-old man with a history of acute pancreatitis developed a pseudoaneurysm of the pancreatic tail, diagnosed as a splenic artery pseudoaneurysm by CT. Selective arteriography performed with the purpose of embolization did not reveal the pseudoaneurysm. The day after, under CT guidance, human thrombin (1,000 IU) was injected inside the aneurysmatic sac with its complete occlusion. A control MRI 6 months later confirmed a complete resolution of the pseudoaneurysm. Conclusions Percutaneous coagulation of a post-pancreatitis pseudoaneurysm is a relatively easy and safe procedure, and it can be considered as an alternative to trans-arterial embolization when the pseudoaneurysm cannot be visualized on selective arteriography. PMID:28203308

  17. Secondary formation of disinfection by-products by UV treatment of swimming pool water.

    PubMed

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M S; Andersen, Henrik R

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  18. A Case of Late Femoral Pseudoaneurysm Caused by Stent Disconnection

    SciTech Connect

    Rivolta, Nicola; Fontana, Federico; Piffaretti, Gabriele Tozzi, Matteo; Carrafiello, Gianpaolo

    2010-10-15

    We present the case of a late superficial femoral artery stent disconnection causing an asymptomatic pseudoaneurysm successfully treated with a stent-graft. A 67-year-old female was referred to our department for evaluation of claudication of the left lower limb and was diagnosed to have a total occlusion of the superficial femoral artery. Three nitinol stents were used to revascularize this artery. At 48 months, duplex-ultrasonography control revealed the presence of a 45-mm saccular femoral dilatation; X-rays and CT angiography showed fractures of the proximal stents and the presence of a pseudoaneurysm at the site of the distal stents disconnection. The pseudoaneurysm was excluded using two stent-grafts. We conclude that patients and surgeons should be aware of structural complications with all stents. Rigorous follow-up controls should be mandatory. Endovascular repair proved to be feasible and durable to manage a previous endovascular procedure.

  19. Sinus of Valsalva Pseudoaneurysm as a Sequela to Infective Endocarditis.

    PubMed

    Lee, Chin C; Siegel, Robert J

    2016-02-01

    Pseudoaneurysm is an uncommon sequela of infective endocarditis. We treated a 44-year-old man who had an active case of group B streptococcal infective endocarditis of the aortic valve despite no evidence of valvular dysfunction or vegetation on his initial transesophageal echocardiogram. After completing 6 weeks of intravenous antibiotic therapy, the patient developed a sinus of Valsalva pseudoaneurysm and severe aortic regurgitation caused by partial detachment of the left coronary cusp. We used a pericardial patch to close the pseudoaneurysm and repair the coronary cusp. This case shows the importance of routine clinical follow-up evaluation in infective endocarditis, even after completion of antibiotic therapy. Late sequelae associated with infective endocarditis or its therapy include recurrent infection, heart failure caused by valvular dysfunction (albeit delayed), and antibiotic toxicity such as aminoglycoside-induced nephropathy and vestibular toxicity.

  20. [Hybrid management of an infectious pseudoaneurysm. Report of one case].

    PubMed

    Sagüés C, Rodrigo; Soto G, Sebastián

    2011-08-01

    We report a 61-year-old male with a four months history of progressive back pain, fever, weight loss and hematuria. A CAT scan showed a spondylitis with destruction of L1 and L2 vertebral bodies and a big pseudoaneurysm of the posterior wall of the visceral aorta. A hybrid approach was used to repair the lesion in two stages; a surgical superior mesenteric artery revascularization followed by the placement of an endovascular stent graft in the affected segment of the aorta 48 hours later, excluding the lesion from circulation. In the postoperative period, no evidence of mesenteric vascular insufficiency was detected but the patient developed a systemic inflammatory response that was managed adequately. A CAT scan performed one month later confirmed the exclusion of the pseudoaneurysm. One year after surgery, the patient is able to walk and without evidences of infection or pseudoaneurysm.

  1. Mechanisms of Formation of Secondary Organic Aerosols and Implications for Global Radiative Forcing

    SciTech Connect

    Seinfeld, John H.

    2011-12-02

    Organic material constitutes about 50% of global atmospheric aerosol mass, and the dominant source of organic aerosol is the oxidation of volatile hydrocarbons, to produce secondary organic aerosol (SOA). Understanding the formation of SOA is crucial to predicting present and future climate effects of atmospheric aerosols. The goal of this program is to significantly increase our understanding of secondary organic aerosol (SOA) formation in the atmosphere. Ambient measurements indicate that the amount of SOA in the atmosphere exceeds that predicted in current models based on existing laboratory chamber data. This would suggest that either the SOA yields measured in laboratory chambers are understated or that all major organic precursors have not been identified. In this research program we are systematically exploring these possibilities.

  2. Peripheral Arterial Pseudoaneurysms-a 10-Year Clinical Study.

    PubMed

    Luther, Anil; Kumar, Amit; Negi, Kamal Nabh Rai

    2015-12-01

    Peripheral arterial pseudoaneurysms are quite common in Northern India (Punjab Province) and thus a common presenting complaint of varied etiology. The objective of this study was to evaluate the clinical outcome of patients presenting with peripheral arterial pseudoaneurysms of varied etiology. Retrospective analysis of medical records of patients with diagnosis of peripheral arterial pseudoaneurysm from 1 May 2001 to 30 October 2009 was done. In the prospective period from 1 November 2009 to 30 April 2011, the patients were personally examined by the authors and followed up till discharge from the hospital and subsequently at 2 weeks, 1 month, 3 months, and 6 months postdischarge from the hospital. We studied 50 patients (13 in the prospective group and 37 in the retrospective study group). Intravenous drug abuse (26 cases) followed by trauma (nine cases) was the commonest etiology. Femoral artery was the commonest artery involved (37 cases). A pulsatile mass with localized tenderness was the commonest presentation. All patients underwent surgical treatment with 36 (72 %) patients undergoing ligation and excision of the pseudoaneurysm. Six (12 %) patients underwent revascularization with reverse saphenous vein graft. Five (10 %) patients underwent primary repair, and three (6 %) patients were managed by putting a synthetic ePTFE graft. Postoperative wound infection was seen in 18 (36 %) patients, and 33 (66 %) patients had an uneventful recovery. In pseudoaneurysms, surgical repair at the early instance carries a favorable prognosis. If feasible, reverse saphenous vein grafting is the best conduit for repair. Synthetic vascular graft (ePTFE) can be used in case autologous saphenous vein is not available. Excision and ligation is safe, and we recommend it as the treatment of choice for infected arterial pseudoaneurysms.

  3. Secondary Organic Aerosol formation from the gas-phase ozonolysis of 3-methylcatechol and 4-methylcatechol

    NASA Astrophysics Data System (ADS)

    Coeur-Tourneur, Cécile; Foulon, Valentine; Laréal, Michel; Cassez, Andy; Zhao, Weixiong

    2010-05-01

    Secondary Organic Aerosol (SOA) formation during the ozonolysis of 3-methylcatechol (3-methyl-1,2-dihydroxybenzene) and 4-methylcatechol (3-methyl-1,2-dihydroxybenzene) was investigated using a simulation chamber (8 m3) at atmospheric pressure, room temperature (294 ± 2 K) and low relative humidity (5-10%). The initial mixing ratios were as follows (in ppb): 3-methylcatechol (194-1059), 4-methylcatechol (204-1188) and ozone (93-531). The ozone and methylcatechol concentrations were followed by UV photometry and GC-FID (Gas Chromatography - Flame ionization detector), respectively and the aerosol production was monitored using a SMPS (Scanning Mobility Particle Sizer). The SOA yields (Y) were determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted methylcatechol concentrations assuming a particle density of 1.4 g cm-3. The aerosol formation yield increases as the initial methylcatechol concentration increases, and leads to aerosol yields ranging from 32% to 67% and from 30% to 64% for 3-methylcatechol and 4-methylcatechol, respectively. Y is a strong function of Mo and the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. These data are comparable to those published in a recent study on secondary organic aerosol formation from catechol ozonolysis. To our knowledge, this work represents the first investigation of SOA formation from the ozone reaction with methylcatechols.

  4. Secondary organic aerosol formation initiated from reactions between ozone and surface-sorbed squalene

    NASA Astrophysics Data System (ADS)

    Wang, Chunyi; Waring, Michael S.

    2014-02-01

    Previous research has shown that ozone reactions on surface-sorbed D-limonene can promote gas phase secondary organic aerosol (SOA) formation indoors. In this work, we conducted 13 steady state chamber experiments to measure the SOA formation entirely initiated by ozone reactions with squalene sorbed to glass, at chamber ozone of 57-500 ppb for two relative humidity (RH) conditions of 21% and 51%, in the absence of seed particles. Squalene is a nonvolatile compound that is a component of human skin oil and prevalent on indoor surfaces and in settled dust due to desquamation. The size distributions, mass and number secondary emission rates (SER), aerosol mass fractions (AMF), and aerosol number fractions (ANF) of formed SOA were quantified. The surface AMF and ANF are defined as the change in SOA mass or number formed, respectively, per ozone mass consumed by ozone-squalene reactions. All experiments but one exhibited nucleation and mass formation. Mass formation was relatively small in magnitude and increased with ozone, most notably for the RH = 51% experiments. The surface AMF was a function of the chamber aerosol concentration, and a multi-product model was fit using the 'volatility basis set' framework. Number formation was relatively strong at low ozone and low RH conditions. Though we cannot extrapolate our results because experiments were conducted at high air exchange rates, we speculate that this process may enhance particle number more than mass concentrations indoors.

  5. Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010

    NASA Astrophysics Data System (ADS)

    Asmi, E.; Kivekäs, N.; Kerminen, V.-M.; Komppula, M.; Hyvärinen, A.-P.; Hatakka, J.; Viisanen, Y.; Lihavainen, H.

    2011-09-01

    Secondary new particle formation affects atmospheric aerosol and cloud droplet numbers and thereby, the aerosol effects on climate. In this paper, the frequency of nucleation events and the associated particle formation and growth rates, along with their seasonal variation, was analysed based on over ten years of aerosol measurements conducted at the Pallas GAW station in northern Finland. The long-term measurements also allowed a detailed examination of factors possibly favouring or suppressing particle formation. Effects of meteorological parameters and air mass properties as well as vapour sources and sinks for particle formation frequency and event parameters were inspected. In addition, the potential of secondary particle formation to increase the concentration of cloud condensation nuclei (CCN) sized particles was examined. Findings from these long-term measurements confirmed previous observations: event frequency peaked in spring and the highest growth rates were observed in summer, affiliated with increased biogenic activity. Events were almost exclusively observed in marine air masses on sunny cloud-free days. A low vapour sink by the background particle population as well as an elevated sulphuric acid concentration were found to favour particle formation. These were also conditions taking place most likely in marine air masses. Inter-annual trend showed a minimum in event frequency in 2003, when also the smallest annual median of growth rate was observed. This gives further evidence of the importance and sensitivity of particle formation for the condensing vapour concentrations at Pallas site. The particle formation was observed to increase CCN80 (>80 nm particle number) concentrations especially in summer and autumn seasons when the growth rates were the highest. When the growing mode exceeded the selected 80 nm limit, on average in those cases, 211 ± 114 % increase of CCN80 concentrations was observed.

  6. Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010

    NASA Astrophysics Data System (ADS)

    Asmi, E.; Kivekäs, N.; Kerminen, V.-M.; Komppula, M.; Hyvärinen, A.-P.; Hatakka, J.; Viisanen, Y.; Lihavainen, H.

    2011-12-01

    Secondary new particle formation affects atmospheric aerosol and cloud droplet numbers and thereby, the aerosol effects on climate. In this paper, the frequency of nucleation events and the associated particle formation and growth rates, along with their seasonal variation, was analysed based on over ten years of aerosol measurements conducted at the Pallas GAW station in northern Finland. The long-term measurements also allowed a detailed examination of factors possibly favouring or suppressing particle formation. Effects of meteorological parameters and air mass properties as well as vapour sources and sinks for particle formation frequency and event parameters were inspected. In addition, the potential of secondary particle formation to increase the concentration of cloud condensation nuclei (CCN) sized particles was examined. Findings from these long-term measurements confirmed previous observations: event frequency peaked in spring and the highest growth rates were observed in summer, affiliated with increased biogenic activity. Events were almost exclusively observed in marine air masses on sunny cloud-free days. A low vapour sink by the background particle population as well as an elevated sulphuric acid concentration were found to favour particle formation. These were also conditions taking place most likely in marine air masses. Inter-annual trend showed a minimum in event frequency in 2003, when also the smallest annual median of growth rate was observed. This gives further evidence of the importance and sensitivity of particle formation for the condensing vapour concentrations at Pallas site. The particle formation was observed to increase CCN80 (>80 nm particle number) concentrations especially in summer and autumn seasons when the growth rates were the highest. When the growing mode exceeded the selected 80 nm limit, on average in those cases, 211 ± 114% increase of CCN80 concentrations was observed.

  7. Endovascular treatment for traumatic thoracic aortic pseudoaneurysm: a case report

    PubMed Central

    2013-01-01

    Cases of an endovascular treatment for traumatic aortic injury are extremely rare. A prompt diagnosis of traumatic thoracic aortic pseudoaneurysm through a 3-dimensional computed tomographic angiography of aorta and emergency repair are mandatory to rescue the life-threatening condition. An endovascular treatment is a trend for traumatic aortic injury because of lower invasivity, morbidity and mortality. We reported a rare case of traumatic aortic injury with thoracic aortic pseudoaneurysm definitively diagnosed by the reconstructional computed tomographic angiography of aorta and successfully treated with endovascular stent-graft. PMID:23452982

  8. Iatrogenic Pseudoaneurysm in the Upper Arm: Treatment by Transcatheter Embolization

    SciTech Connect

    Maleux, Geert; Stockx, Luc; Brys, Peter; Lammens, Johan; Lacroix, Hendrik; Wilms, Guy; Marchal, Guy

    2000-03-15

    A 32-year-old woman presented with a pulsatile, painful mass in her left upper arm, originating several days after removal of an Ilizarov external fixation. The diagnosis of a pseudoaneurysm was made by medical history and by physical and ultrasonographic examination of the mass. Angiography confirmed the presence of the pseudoaneurysm, originating from a branch of the arteria profunda brachii, and definitive treatment was performed by transcatheter embolization. Clinical follow-up showed absence of pulsation and pain in the upper arm and a gradual volume decrease of the mass lesion.

  9. Embolization of an Hepatic Artery Pseudoaneurysm Following Laparoscopic Cholecystectomy

    SciTech Connect

    Rivitz, S. Mitchell; Waltman, Arthur C.; Kelsey, Peter B.

    1996-11-15

    Vascular injuries during laparoscopic cholecystectomy can occur in an analogous fashion to biliary injuries, with potential laceration, transection, and occlusion of blood vessels. A patient presented with symptomatic hemobilia 1 month following laparoscopic cholecystectomy and was found to have a right hepatic artery pseudoaneurysm which communicated with the common bile duct. This was successfully embolized with several embolic agents, resulting in rapid resolution of all signs and symptoms. The patient has been free of symptoms during a follow-up period of 1 year. A brief discussion of hepatic artery pseudoaneurysms is presented.

  10. Formation of secondary aerosols from gasoline vehicle exhaust when mixing with SO2

    NASA Astrophysics Data System (ADS)

    Liu, T.; Wang, X.; Hu, Q.; Deng, W.; Zhang, Y.; Ding, X.; Fu, X.; Bernard, F.; Zhang, Z.; Lü, S.; He, Q.; Bi, X.; Chen, J.; Sun, Y.; Yu, J.; Peng, P.; Sheng, G.; Fu, J.

    2016-01-01

    Sulfur dioxide (SO2) can enhance the formation of secondary aerosols from biogenic volatile organic compounds (VOCs), but its influence on secondary aerosol formation from anthropogenic VOCs, particularly complex mixtures like vehicle exhaust, remains uncertain. Gasoline vehicle exhaust (GVE) and SO2, a typical pollutant from coal burning, are directly co-introduced into a smog chamber, in this study, to investigate the formation of secondary organic aerosols (SOA) and sulfate aerosols through photooxidation. New particle formation was enhanced, while substantial sulfate was formed through the oxidation of SO2 in the presence of high concentration of SO2. Homogenous oxidation by OH radicals contributed a negligible fraction to the conversion of SO2 to sulfate, and instead the oxidation by stabilized Criegee intermediates (sCIs), formed from alkenes in the exhaust reacting with ozone, dominated the conversion of SO2. After 5 h of photochemical aging, GVE's SOA production factor revealed an increase by 60-200 % in the presence of high concentration of SO2. The increase could principally be attributed to acid-catalyzed SOA formation as evidenced by the strong positive linear correlation (R2 = 0.97) between the SOA production factor and in situ particle acidity calculated by the AIM-II model. A high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) resolved OA's relatively lower oxygen-to-carbon (O : C) (0.44 ± 0.02) and higher hydrogen-to-carbon (H : C) (1.40 ± 0.03) molar ratios for the GVE / SO2 mixture, with a significantly lower estimated average carbon oxidation state (OSc) of -0.51 ± 0.06 than -0.19 ± 0.08 for GVE alone. The relative higher mass loading of OA in the experiments with SO2 might be a significant explanation for the lower SOA oxidation degree.

  11. Formation of secondary aerosols from gasoline vehicle exhausts when mixing with SO2

    NASA Astrophysics Data System (ADS)

    Liu, T.; Wang, X.; Hu, Q.; Deng, W.; Zhang, Y.; Ding, X.; Fu, X.; Bernard, F.; Zhang, Z.; Lü, S.; He, Q.; Bi, X.; Chen, J.; Sun, Y.; Yu, J.; Peng, P.; Sheng, G.; Fu, J.

    2015-09-01

    Sulfur dioxide (SO2) can enhance the formation of secondary aerosols from biogenic volatile organic compounds (VOCs), but its influence on secondary aerosol formation from anthropogenic VOCs, particularly complex mixtures like vehicle exhausts, is still poorly understood. Here we directly co-introduced gasoline vehicles exhausts (GVE) and SO2, a typical pollutant from coal burning, into a smog chamber to investigate the formation of secondary organic aerosols (SOA) and sulfate aerosols through photooxidation. In the presence of high concentration of SO2, new particle formation was enhanced while substantial sulfate was formed through the oxidation of SO2. The homogenous oxidation by OH radicals contributed a negligible fraction to the conversion of SO2 to sulfate, and instead the oxidation by stabilized Criegee intermediates (sCIs), formed from alkenes in the exhaust reacting with ozone, dominated the conversion of SO2. After 5 h of photochemical aging, GVE's SOA production factor revealed an increase by 60-200 % in the presence of high concentration of SO2. This increase could largely be attributed to acid-catalyzed SOA formation, which was evidenced by the strong positive linear correlation (R2 = 0.97) between the SOA production factor and in-situ particle acidity calculated by AIM-II model. A high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) resolved OA's relatively lower oxygen-to-carbon (O : C) and higher hydrogen-to-carbon (H : C) molar ratios for the GVE/SO2 mixture, with a much lower estimated average carbon oxidation state (OSc) of -0.51 ± 0.06 than that of -0.19 ± 0.08 for GVE alone. The relative higher mass loading of OA in the experiments with SO2 might be the major reason for the lower oxidation degree of SOA.

  12. Oligomerization reaction of the Criegee intermediate leads to secondary organic aerosol formation in ethylene ozonolysis.

    PubMed

    Sakamoto, Yosuke; Inomata, Satoshi; Hirokawa, Jun

    2013-12-05

    Ethylene ozonolysis was investigated in laboratory experiments using a Teflon bag reactor. A negative ion chemical ionization mass spectrometer (NI-CIMS) using SO2Cl(-) and Cl(-) as reagent ions was used for product analysis. In addition to the expected gas-phase products, such as formic acid and hydroperoxymethyl formate, oligomeric hydroperoxides composed of the Criegee intermediate (CH2OO) as a chain unit were observed. Furthermore, we observed secondary organic aerosol (SOA) formation from the ethylene ozonolysis, and the particle-phase products were also analyzed by NI-CIMS. The CH2OO oligomers were also observed as particle-phase components, suggesting that the oligomeric hydroperoxides formed in the gas phase partition into the particle phase. By adding methanol as a stabilized Criegee intermediate scavenger, both the gas-phase oligomer formation and SOA formation were strongly suppressed. This indicates that CH2OO plays a critical role in the formation of oligomeric hydroperoxides followed by SOA formation in ethylene ozonolysis. A new formation mechanism for the oligomeric hydroperoxides, which includes sequential addition of CH2OO to hydroperoxides, is proposed.

  13. Secondary organic aerosol formation from isoprene photooxidation during cloud condensation-evaporation cycles

    NASA Astrophysics Data System (ADS)

    Brégonzio-Rozier, L.; Giorio, C.; Siekmann, F.; Pangui, E.; Morales, S. B.; Temime-Roussel, B.; Gratien, A.; Michoud, V.; Cazaunau, M.; DeWitt, H. L.; Tapparo, A.; Monod, A.; Doussin, J.-F.

    2016-02-01

    The impact of cloud events on isoprene secondary organic aerosol (SOA) formation has been studied from an isoprene / NOx / light system in an atmospheric simulation chamber. It was shown that the presence of a liquid water cloud leads to a faster and higher SOA formation than under dry conditions. When a cloud is generated early in the photooxidation reaction, before any SOA formation has occurred, a fast SOA formation is observed with mass yields ranging from 0.002 to 0.004. These yields are 2 and 4 times higher than those observed under dry conditions. When the cloud is generated at a later photooxidation stage, after isoprene SOA is stabilized at its maximum mass concentration, a rapid increase (by a factor of 2 or higher) of the SOA mass concentration is observed. The SOA chemical composition is influenced by cloud generation: the additional SOA formed during cloud events is composed of both organics and nitrate containing species. This SOA formation can be linked to the dissolution of water soluble volatile organic compounds (VOCs) in the aqueous phase and to further aqueous phase reactions. Cloud-induced SOA formation is experimentally demonstrated in this study, thus highlighting the importance of aqueous multiphase systems in atmospheric SOA formation estimations.

  14. Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Veres, P. R.; Warneke, C.; Roberts, J. M.; Gilman, J. B.; Koss, A.; Edwards, P. M.; Graus, M.; Kuster, W. C.; Li, S.-M.; Wild, R. J.; Brown, S. S.; Dubé, W. P.; Lerner, B. M.; Williams, E. J.; Johnson, J. E.; Quinn, P. K.; Bates, T. S.; Lefer, B.; Hayes, P. L.; Jimenez, J. L.; Weber, R. J.; Zamora, R.; Ervens, B.; Millet, D. B.; Rappenglück, B.; de Gouw, J. A.

    2014-09-01

    Formic acid (HCOOH) is one of the most abundant carboxylic acids in the atmosphere. However, current photochemical models cannot fully explain observed concentrations and in particular secondary formation of formic acid across various environments. In this work, formic acid measurements made at an urban receptor site in June-July of 2010 during CalNex and a site in an oil and gas producing region in January-February of 2013 during UBWOS 2013 will be discussed. Although the VOC compositions differed dramatically at the two sites, measured formic acid concentrations were comparable: 2.3 ± 1.3 ppb in UBWOS 2013 and 2.0 ± 1.0 ppb in CalNex. We determine that concentrations of formic acid at both sites were dominated by secondary formation (> 8%). A constrained box model using the Master Chemical Mechanism (MCM v3.2) underestimates the measured formic acid concentrations drastically at both sites (by a factor of > 10). Inclusion of recent findings on additional precursors and formation pathways of formic acid in the box model increases modeled formic acid concentrations for UBWOS 2013 and CalNex by a factor of 6.4 and 4.5, respectively. A comparison of measured and modeled HCOOH/acetone ratios is used to evaluate the model performance for formic acid. We conclude that the modified chemical mechanism can explain 21 and 47% of secondary formation of formic acid in UBWOS 2013 and CalNex, respectively. The contributions from aqueous reactions in aerosol and heterogeneous reactions on aerosol surface to formic acid are estimated to be -7 and 0-6% in UBWOS 2013 and CalNex, respectively. We observe that air-snow exchange processes and morning fog events may also contribute to ambient formic acid concentrations during UBWOS 2013 (∼20% in total). In total, 50-57% in UBWOS 2013 and 48-53% in CalNex of secondary formation of formic acid remains unexplained. More work on formic acid formation pathways is needed to reduce the uncertainties in the sources and budget of formic

  15. Dynamics of protein aggregation and oligomer formation governed by secondary nucleation

    NASA Astrophysics Data System (ADS)

    Michaels, Thomas C. T.; Lazell, Hamish W.; Arosio, Paolo; Knowles, Tuomas P. J.

    2015-08-01

    The formation of aggregates in many protein systems can be significantly accelerated by secondary nucleation, a process where existing assemblies catalyse the nucleation of new species. In particular, secondary nucleation has emerged as a central process controlling the proliferation of many filamentous protein structures, including molecular species related to diseases such as sickle cell anemia and a range of neurodegenerative conditions. Increasing evidence suggests that the physical size of protein filaments plays a key role in determining their potential for deleterious interactions with living cells, with smaller aggregates of misfolded proteins, oligomers, being particularly toxic. It is thus crucial to progress towards an understanding of the factors that control the sizes of protein aggregates. However, the influence of secondary nucleation on the time evolution of aggregate size distributions has been challenging to quantify. This difficulty originates in large part from the fact that secondary nucleation couples the dynamics of species distant in size space. Here, we approach this problem by presenting an analytical treatment of the master equation describing the growth kinetics of linear protein structures proliferating through secondary nucleation and provide closed-form expressions for the temporal evolution of the resulting aggregate size distribution. We show how the availability of analytical solutions for the full filament distribution allows us to identify the key physical parameters that control the sizes of growing protein filaments. Furthermore, we use these results to probe the dynamics of the populations of small oligomeric species as they are formed through secondary nucleation and discuss the implications of our work for understanding the factors that promote or curtail the production of these species with a potentially high deleterious biological activity.

  16. Dynamics of protein aggregation and oligomer formation governed by secondary nucleation

    SciTech Connect

    Michaels, Thomas C. T. Lazell, Hamish W.; Arosio, Paolo; Knowles, Tuomas P. J.

    2015-08-07

    The formation of aggregates in many protein systems can be significantly accelerated by secondary nucleation, a process where existing assemblies catalyse the nucleation of new species. In particular, secondary nucleation has emerged as a central process controlling the proliferation of many filamentous protein structures, including molecular species related to diseases such as sickle cell anemia and a range of neurodegenerative conditions. Increasing evidence suggests that the physical size of protein filaments plays a key role in determining their potential for deleterious interactions with living cells, with smaller aggregates of misfolded proteins, oligomers, being particularly toxic. It is thus crucial to progress towards an understanding of the factors that control the sizes of protein aggregates. However, the influence of secondary nucleation on the time evolution of aggregate size distributions has been challenging to quantify. This difficulty originates in large part from the fact that secondary nucleation couples the dynamics of species distant in size space. Here, we approach this problem by presenting an analytical treatment of the master equation describing the growth kinetics of linear protein structures proliferating through secondary nucleation and provide closed-form expressions for the temporal evolution of the resulting aggregate size distribution. We show how the availability of analytical solutions for the full filament distribution allows us to identify the key physical parameters that control the sizes of growing protein filaments. Furthermore, we use these results to probe the dynamics of the populations of small oligomeric species as they are formed through secondary nucleation and discuss the implications of our work for understanding the factors that promote or curtail the production of these species with a potentially high deleterious biological activity.

  17. Mechanisms for Secondary Eyewall Formation in Tropical Cyclones: A Case Study of Hurricane Katrina (2005)

    NASA Astrophysics Data System (ADS)

    Garcia-Rivera, J. M.; Lin, Y.

    2013-05-01

    The Weather Research and Forecast (WRF) model is used to simulate the last eyewall replacement cycle (ERC) of Hurricane Katrina (2005) just before it's landfall in the Louisiana coastline. In this study, we pursue a complete understanding of the physics behind the secondary eyewall formation (SEF) in tropical cyclones. The simulation results show the occurrence of the early stages of an ERC in the simulated storm just before landfall. This confirms that with the appropriate set of physics parameterization schemes, grid spacing and initial conditions, the numerical model is able to reproduce ERCs on certain tropical cyclones with no data assimilation or extra data inputs. Strong updrafts are observed to converge in a ring outside the primary eyewall of Hurricane Katrina (2005) suggesting SEF during that period. The increase of divergence outside the primary eyewall with an outer-ring of convergence forming above the boundary layer can be part of the mechanisms that lead to SEF. Also, potential vorticity (PV) field is analyzed for its possible relationship with the development of the secondary eyewall. This detailed study of the pre-ERC events in the inner-core of Hurricane Katrina can build the foundations for testing some of the existing hypotheses for the development of secondary eyewalls leading to new ideas behind their formation.

  18. The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis.

    PubMed

    Getoff, Nikola; Gerschpacher, Marion; Hartmann, Johannes; Huber, Johannes C; Schittl, Heike; Quint, Ruth Maria

    2010-01-21

    4-Hydroxyestrone (4-OHE(1)), a typical cancer-inducing metabolite, originating from 17beta-estradiol (17beta-E2), was chosen as a model for the studies. The aim was to get a deeper insight in the mechanisms of its ability to initiate cancer. It was found, that 4-OHE(1) can eject electrons (e(aq)(-)), when excited in the singlet state by monochromatic UV-light (lambda=254 nm) in polar media (water:ethanol=40:60 vol.%). The quantum yield Q(e(aq)(-)), determined for various 4-OHE(1) concentrations, is found to be as high as that previously observed for 17beta-E2. It decreases with increasing substrate concentration, but it is enhanced at higher temperature. The ability of 4-OHE(1) to eject as well as to consume and to transfer electrons to other biological systems, classifies it as an electron mediator, similar to 17beta-E2. The 4-OHE(1) transients resulting of the electron emission process are leading to the formation of secondary metabolites. Surprisingly, it was established that the secondary metabolites possess likewise the ability to eject as well as to consume electrons. Hence, they behave similar like 17beta-E2. However, the structure of the secondary formed metabolites, which determinates their biological properties and carcinogenity, depends on the nature of the available reaction partners involved in their formation. A probable reaction mechanism explaining the subject matter is discussed.

  19. Monitoring Single-Stranded DNA Secondary Structure Formation by Determining the Topological State of DNA Catenanes

    PubMed Central

    Liang, Xingguo; Kuhn, Heiko; Frank-Kamenetskii, Maxim D.

    2006-01-01

    Single-stranded DNA (ssDNA) has essential biological functions during DNA replication, recombination, repair, and transcription. The structure of ssDNA must be better understood to elucidate its functions. However, the available data are too limited to give a clear picture of ssDNA due to the extremely capricious structural features of ssDNA. In this study, by forming DNA catenanes and determining their topology (the linking number, Lk) through the electrophoretic analysis, we demonstrate that the studies of catenanes formed from two ssDNA molecules can yield valuable new information about the ssDNA secondary structure. We construct catenanes out of two short (60/70 nt) ssDNA molecules by enzymatic cyclization of linear oligodeoxynucleotides. The secondary structure formed between the two DNA circles determines the topology (the Lk value) of the constructed DNA catenane. Thus, formation of the secondary structure is experimentally monitored by observing the changes of linking number with sequences and conditions. We found that the secondary structure of ssDNA is much easier to form than expected: the two strands in an internal loop in the folded ssDNA structure prefer to braid around each other rather than stay separately forming a loop, and a duplex containing only mismatched basepairs can form under physiological conditions. PMID:16461397

  20. A set of nearest neighbor parameters for predicting the enthalpy change of RNA secondary structure formation

    PubMed Central

    Lu, Zhi John; Turner, Douglas H.; Mathews, David H.

    2006-01-01

    A complete set of nearest neighbor parameters to predict the enthalpy change of RNA secondary structure formation was derived. These parameters can be used with available free energy nearest neighbor parameters to extend the secondary structure prediction of RNA sequences to temperatures other than 37°C. The parameters were tested by predicting the secondary structures of sequences with known secondary structure that are from organisms with known optimal growth temperatures. Compared with the previous set of enthalpy nearest neighbor parameters, the sensitivity of base pair prediction improved from 65.2 to 68.9% at optimal growth temperatures ranging from 10 to 60°C. Base pair probabilities were predicted with a partition function and the positive predictive value of structure prediction is 90.4% when considering the base pairs in the lowest free energy structure with pairing probability of 0.99 or above. Moreover, a strong correlation is found between the predicted melting temperatures of RNA sequences and the optimal growth temperatures of the host organism. This indicates that organisms that live at higher temperatures have evolved RNA sequences with higher melting temperatures. PMID:16982646

  1. Formation flavonoid secondary metabolites in callus culture of Chrysanthemum cinerariefolium as alternative provision medicine

    NASA Astrophysics Data System (ADS)

    Purwianingsih, Widi; Febri, Santika; Kusdianti

    2016-02-01

    Increasing need of medicine ingredients require the discovery of other methods that can be used as an alternative. One method that can be used as an alternative is tissue culture. Quercetin is a flavonoid secondary metabolites that have been known to be useful as antiviral, anti-asthma and anti-cancer potential. The purpose of this study was to produce flavonoids, especially quercetin in callus culture Chrysanthemum cinerariefolium. Pieces of leaves of plantlets C. cinerariefolium used as explants for formation of callus tissue. To grow the callus, Murashige and Skoog (MS) medium used with addition of various concentrations of growth regulators 2.4-D, and kinetin. For multiplication, callus subcultured on similar medium. Callus that had formed, especially brown callus, further analyzed using Gas Chromatography Mass Spectrum (GCMS). Before analyzed callus was extracted in 95% ethanol. The result showed that callus potentially generate secondary metabolite are brown and friable. Based on these parameters, the best callus produced from leaf explants grown on MS medium with the addition of 4 mg / L 2,4-D and 0 mg / L kinetin. The callus contain secondary metabolites such as some of the flavonoid quercetin precursors such as acetic acid and tetrahydroxychalcone, and some other secondary metabolites.

  2. Secondary aerosol formation from stress-induced biogenic emissions and possible climate feedbacks

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Kleist, E.; Andres, S.; Dal Maso, M.; Hohaus, T.; Kiendler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

    2013-09-01

    Atmospheric aerosols impact climate by scattering and absorbing solar radiation and by acting as ice and cloud condensation nuclei. Biogenic secondary organic aerosols (BSOAs) comprise an important component of atmospheric aerosols. Biogenic volatile organic compounds (BVOCs) emitted by vegetation are the source of BSOAs. Pathogens and insect attacks, heat waves and droughts can induce stress to plants that may impact their BVOC emissions, and hence the yield and type of formed BSOAs, and possibly their climatic effects. This raises questions of whether stress-induced changes in BSOA formation may attenuate or amplify effects of climate change. In this study we assess the potential impact of stress-induced BVOC emissions on BSOA formation for tree species typical for mixed deciduous and Boreal Eurasian forests. We studied the photochemical BSOA formation for plants infested by aphids in a laboratory setup under well-controlled conditions and applied in addition heat and drought stress. The results indicate that stress conditions substantially modify BSOA formation and yield. Stress-induced emissions of sesquiterpenes, methyl salicylate, and C17-BVOCs increase BSOA yields. Mixtures including these compounds exhibit BSOA yields between 17 and 33%, significantly higher than mixtures containing mainly monoterpenes (4-6% yield). Green leaf volatiles suppress SOA formation, presumably by scavenging OH, similar to isoprene. By classifying emission types, stressors and BSOA formation potential, we discuss possible climatic feedbacks regarding aerosol effects. We conclude that stress situations for plants due to climate change should be considered in climate-vegetation feedback mechanisms.

  3. Secondary Organic Aerosol Formation from m-Xylene in the Absence of NOx

    SciTech Connect

    Song, Chen; Na, Kwangsam; Warren, Bethany; Malloy, Quentin; Cocker, David R.

    2007-11-01

    Formation of secondary organic aerosol (SOA) from m-xylene photoxidation in the absence of NOx was investigated in a series of smog chamber experiments. Experiments were performed in dry air and in the absence of seed aerosol with H2O2 photolysis providing a stable hydroxyl radical (OH radical) source. SOA formation from this study is exceptionally higher than experiments with existence of NOx. The experiments with elevated HO2 levels indicate that organic hydroperoxide compounds should contribute to SOA formation. Nitrogen oxide (NO) is shown to reduce aerosol formation; the constant aerosol formation rate obtained before addition of NO and after consumption of NO strongly suggests that aerosol formation is mainly through reactions with OH and HO2 radicals. In addition, a density of 1.40 ± 0.1 g cm-3 for the SOA from the photooxidation of m-xylene in the absence of NOx has been measured, which is significantly higher than the currently used unit density.

  4. Secondary aerosol formation from stress-induced biogenic emissions and possible climate feedbacks

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Kleist, E.; Andres, S.; Maso, M. D.; Hohaus, T.; Kiendler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

    2013-03-01

    Atmospheric aerosols impact climate by scattering and absorbing solar radiation and by acting as ice and cloud condensation nuclei. Secondary organic aerosols (SOA) comprise an important component of atmospheric aerosols. Biogenic volatile organic compounds (BVOC) emitted by vegetation are a major source of SOA. Pathogens and insect attacks, heat waves and droughts can induce stress to plants that may impact their BVOC emissions, and hence the yield and type of formed SOA, and possibly their climatic effects. This raises questions whether stress-induced changes in SOA formation may attenuate or amplify effects of climate change. In this study we assess the potential impact of stress-induced BVOC emissions on SOA formation for tree species typical for mixed deciduous and Boreal Eurasian forests. We studied the photochemical SOA formation for infested plants in a laboratory setup under well-controlled conditions and applied in addition heat and drought stress. The results indicate that stress conditions substantially modify SOA formation. While sesquiterpenes, methyl salicylate, and C17-BVOC increase SOA yield, green leaf volatiles suppress SOA formation. By classifying emission types, stressors and SOA formation potential, we propose possible climatic feedbacks regarding aerosol effects. We conclude that stress situations for plants due to climate change should be considered in climate-vegetation feedback mechanisms.

  5. Traumatic pseudoaneurysm of left internal mammary artery graft.

    PubMed

    Agathos, E A; Hussein, A; Trehan, H; Trenholme, S E; Floten, H S

    1993-10-01

    Traumatic pseudoaneurysm of the left internal mammary artery was recognized as a possible causal factor in the early recurrence of angina in a 51-year-old man. This patient underwent reoperation for revascularization with the left internal mammary artery graft in situ.

  6. Pseudoaneurysm of the left atrium following infective endocarditis

    PubMed Central

    Manuel, Devi A; Sahayo, Bino John; Thomson, Viji Samuel; Jose, Jacob

    2017-01-01

    Transthoracic echocardiogram of a 3-year-old child showed a hypoechoic cavity in the posterior wall of the left atrium communicating with the left ventricle through an orifice in the mitral annulus, suggestive of pseudoaneurysm (Ps), probably the result of infective endocarditis. Three-dimensional echocardiography was helpful to confirm the diagnosis and assess the anatomical relationship of the Ps. PMID:28163437

  7. Endovascular pseudoaneurysm repair after distal pancreatectomy with celiac axis resection

    PubMed Central

    Sumiyoshi, Tatsuaki; Shima, Yasuo; Noda, Yoshihiro; Hosoki, Shingo; Hata, Yasuhiro; Okabayashi, Takehiro; Kozuki, Akihito; Nakamura, Toshio

    2013-01-01

    Erosive hemorrhage due to pseudoaneurysm is one of the most life-threatening complications after pancreatectomy. Here, we report an extremely rare case of rupture of a pseudoaneurysm of the common hepatic artery (CHA) stump that developed after distal pancreatectomy with en block celiac axis resection (DP-CAR), and was successfully treated through covered stent placement. The patient is a 66-year-old woman who underwent DP-CAR after adjuvant chemoradiotherapy for locally advanced pancreatic body cancer. She developed an intra-abdominal abscess around the remnant pancreas head 31 d after the surgery, and computed tomography (CT) showed an occluded portal vein due to the spreading inflammation around the abscess. Her general condition improved after CT-guided drainage of the abscess. However, 19 d later, she presented with melena, and CT showed a pseudoaneurysm arising from the CHA stump. Because the CHA had been resected during the DP-CAR, this artery could not be used as the access route for endovascular treatment, and instead, we placed a covered stent via the inferior pancreaticoduodenal artery originating from the superior mesenteric artery. After stent placement, cessation of bleeding and anterograde hepatic artery flow were confirmed, and the patient recovered well without any further complications. CT angiography at the 6-mo follow-up indicated the patency of the covered stent with sustained hepatic artery flow. To our knowledge, this is the first reported case of endovascular repair of a pseudoaneurysm that developed after DP-CAR. PMID:24363537

  8. Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Veres, P. R.; Warneke, C.; Roberts, J. M.; Gilman, J. B.; Koss, A.; Edwards, P. M.; Graus, M.; Kuster, W. C.; Li, S.-M.; Wild, R. J.; Brown, S. S.; Dubé, W. P.; Lerner, B. M.; Williams, E. J.; Johnson, J. E.; Quinn, P. K.; Bates, T. S.; Lefer, B.; Hayes, P. L.; Jimenez, J. L.; Weber, R. J.; Zamora, R.; Ervens, B.; Millet, D. B.; Rappenglück, B.; de Gouw, J. A.

    2015-02-01

    Formic acid (HCOOH) is one of the most abundant carboxylic acids in the atmosphere. However, current photochemical models cannot fully explain observed concentrations and in particular secondary formation of formic acid across various environments. In this work, formic acid measurements made at an urban receptor site (Pasadena) in June-July 2010 during CalNex (California Research at the Nexus of Air Quality and Climate Change) and a site in an oil and gas producing region (Uintah Basin) in January-February 2013 during UBWOS 2013 (Uintah Basin Winter Ozone Studies) will be discussed. Although the VOC (volatile organic compounds) compositions differed dramatically at the two sites, measured formic acid concentrations were comparable: 2.3 ± 1.3 in UBWOS 2013 and 2.0 ± 1.0 ppb in CalNex. We determine that concentrations of formic acid at both sites were dominated by secondary formation (> 99%). A constrained box model using the Master Chemical Mechanism (MCM v3.2) underestimates the measured formic acid concentrations drastically at both sites (by a factor of > 10). Compared to the original MCM model that includes only ozonolysis of unsaturated organic compounds and OH oxidation of acetylene, when we updated yields of ozonolysis of alkenes and included OH oxidation of isoprene, vinyl alcohol chemistry, reaction of formaldehyde with HO2, oxidation of aromatics, and reaction of CH3O2 with OH, the model predictions for formic acid were improved by a factor of 6.4 in UBWOS 2013 and 4.5 in CalNex, respectively. A comparison of measured and modeled HCOOH/acetone ratios is used to evaluate the model performance for formic acid. We conclude that the modified chemical mechanism can explain 19 and 45% of secondary formation of formic acid in UBWOS 2013 and CalNex, respectively. The contributions from aqueous reactions in aerosol and heterogeneous reactions on aerosol surface to formic acid are estimated to be 0-6 and 0-5% in UBWOS 2013 and CalNex, respectively. We observe that

  9. Secondary Organic Aerosol formation from the gas-phase reaction of catechol with ozone

    NASA Astrophysics Data System (ADS)

    Coeur-Tourneur, C.; Tomas, A.; Guilloteau, A.; Henry, F.; Ledoux, F.; Visez, N.; Riffault, V.; Wenger, J. C.; Bedjanian, Y.; Foulon, V.

    2009-04-01

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers (at the LPCA in France and at the CRAC in Ireland). Aerosol production was monitored using a scanning mobility particle sizer. The overall organic aerosol yield (Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm-3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The aerosol yields determined in the LPCA and CRAC smog chambers were comparable and were also in accordance with those determined in a previous study performed in EUPHORE (EUropean PHOto REactor, Spain).

  10. Contribution of secondary condensable organics to new particle formation: A case study in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Fan, Jiwen; Zhang, Renyi; Collins, Don; Li, Guohui

    2006-08-01

    We report aerosol simulations using the EPA's Models-3 Community Multiscale Air Quality model (CMAQ) and ground-based and aircraft aerosol measurements to investigate new particle formation in Houston, Texas. The aerosol measurements reveal elevated ultrafine particles that reach the highest value in the afternoon, indicating prominent new particle formation. Simulations of the binary H2SO4-H2O nucleation predict an order of magnitude lower concentrations for aerosols near 10 nm than the measurements. A parameterized nucleation scheme that accounts for the enhanced nucleation effect of secondary condensable organics is incorporated into the Models-3/CMAQ. The organic nucleation scheme predicts the number concentrations in agreement with the measurements during the daytime. The diurnal variation is well reproduced in the simulations including the organic nucleation scheme. Comparison with the aircraft measurements also shows that the organic nucleation scheme produces good predictions of the altitude-dependent number size distributions of the ultrafine particles. The results corroborate the importance of secondary condensable organics in new particle formation when sulfate and organics are abundant.

  11. Contribution of methyl group to secondary organic aerosol formation from aromatic hydrocarbon photooxidation

    NASA Astrophysics Data System (ADS)

    Li, Lijie; Qi, Li; Cocker, David R.

    2017-02-01

    The complete atmospheric oxidation pathways leading to secondary organic aerosol remain elusive for aromatic compounds including the role of methyl substitutes on oxidation. This study investigates the contribution of methyl group to Secondary Organic Aerosol (SOA) formation during the photooxidation of aromatic hydrocarbons under low NOx condition by applying methyl carbon labeled aromatic hydrocarbons ((13C2) m-xylene and (13C2) p-xylene). Particle and gas phase oxidation products are analyzed by a series of mass spectrometers (HR-TOF-AMS, PTR-MS and SIFT-MS). The methyl group carbon containing oxidation products partition to the particle-phase at a lower rate than the carbons originating from the aromatic ring as a result of ring opening reactions. Further, the methyl carbon in the original aromatic structure is at least 7 times less likely to be oxidized when forming products that partition to SOA than the aromatic ring carbon. Therefore, oxidation of the methyl group in xylenes exerts little impact on SOA formation in current study. This study provides supporting evidence for a recent finding - a similarity in the SOA formation and composition from aromatic hydrocarbons regardless of the alkyl substitutes.

  12. Optimized Jasmonic Acid Production by Lasiodiplodia theobromae Reveals Formation of Valuable Plant Secondary Metabolites

    PubMed Central

    Eng, Felipe; Haroth, Sven; Feussner, Kirstin; Meldau, Dorothea; Rekhter, Dmitrij; Ischebeck, Till; Brodhun, Florian

    2016-01-01

    Jasmonic acid is a plant hormone that can be produced by the fungus Lasiodiplodia theobromae via submerged fermentation. From a biotechnological perspective jasmonic acid is a valuable feedstock as its derivatives serve as important ingredients in different cosmetic products and in the future it may be used for pharmaceutical applications. The objective of this work was to improve the production of jasmonic acid by L. theobromae strain 2334. We observed that jasmonic acid formation is dependent on the culture volume. Moreover, cultures grown in medium containing potassium nitrate as nitrogen source produced higher amounts of jasmonic acid than analogous cultures supplemented with ammonium nitrate. When cultivated under optimal conditions for jasmonic acid production, L. theobromae secreted several secondary metabolites known from plants into the medium. Among those we found 3-oxo-2-(pent-2-enyl)-cyclopentane-1-butanoic acid (OPC-4) and hydroxy-jasmonic acid derivatives, respectively, suggesting that fungal jasmonate metabolism may involve similar reaction steps as that of plants. To characterize fungal growth and jasmonic acid-formation, we established a mathematical model describing both processes. This model may form the basis of industrial upscaling attempts. Importantly, it showed that jasmonic acid-formation is not associated to fungal growth. Therefore, this finding suggests that jasmonic acid, despite its enormous amount being produced upon fungal development, serves merely as secondary metabolite. PMID:27907207

  13. Formation of secondary organic aerosol in the Paris pollution plume and its impact on surrounding regions

    NASA Astrophysics Data System (ADS)

    Zhang, Q. J.; Beekmann, M.; Freney, E.; Sellegri, K.; Pichon, J. M.; Schwarzenboeck, A.; Colomb, A.; Bourrianne, T.; Michoud, V.; Borbon, A.

    2015-03-01

    Secondary pollutants such as ozone, secondary inorganic aerosol, and secondary organic aerosol formed in the plume of megacities can affect regional air quality. In the framework of the FP7/EU MEGAPOLI project, an intensive campaign was launched in the Greater Paris Region in July 2009. The major objective was to quantify different sources of organic aerosol (OA) within a megacity and in its plume. In this study, we use airborne measurements aboard the French ATR-42 aircraft to evaluate the regional chemistry-transport model CHIMERE within and downwind the Paris region. Slopes of the plume OA levels vs. Ox (= O3 + NO2) show secondary OA (SOA) formation normalized with respect to photochemical activity and are used for specific evaluation of the OA scheme in the model. Simulated and observed slopes are in good agreement, when the most realistic "high-NOx" yields are used in the Volatility-Basis-Set scheme implemented into the model. In addition, these slopes are relatively stable from one day to another, which suggest that they are characteristic for the given megacity plume environment. Since OA within the plume is mainly formed from anthropogenic precursors (VOC and primary OA, POA), this work allows a specific evaluation of anthropogenic SOA and SOA formed from primary semi-volatile and intermediate volatile VOCs (SI-SOA) formation scheme in a model. For specific plumes, this anthropogenic OA build-up can reach about 10 μg m-3. For the average of the month of July 2009, maximum increases occur close to the agglomeration for primary OA are noticed at several tens (for POA) to hundred (for SI-SOA) kilometers of distance from the Paris agglomeration.

  14. Formation mechanism of the secondary building unit in a chromium terephthalate metal-organic framework

    SciTech Connect

    Cantu Cantu, David; McGrail, B. Peter; Glezakou, Vassiliki Alexandra

    2014-09-18

    Based on density functional theory calculations and simulation, a detailed mechanism is presented on the formation of the secondary building unit (SBU) of MIL-101, a chromium terephthalate metal-organic framework (MOF). SBU formation is key to MOF nucleation, the rate-limiting step in the formation process of many MOFs. A series of reactions that lead to the formation of the SBU of MIL-101 is proposed in this work. Initial rate-limiting reactions form the metal cluster with three chromium (III) atoms linked to a central bridging oxygen. Terephthalate linkers play a key role as chromium (III) atoms are joined to linker carboxylate groups prior to the placement of the central bridging oxygen. Multiple linker addition reactions, which follow in different paths due to structural isomers, are limited by the removal of water molecules in the first chromium coordination shell. The least energy path is identified were all linkers on one face of the metal center plane are added first. A simple kinetic model based on transition state theory shows the rate of secondary building unit formation similar to the rate metal-organic framework nucleation. The authors are thankful to Dr. R. Rousseau for a critical reading of the manuscript. This research would not have been possible without the support of the Office of Fossil Energy, U.S. Department of Energy. This research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and the PNNL Institutional Computing (PIC) program located at Pacific Northwest National Laboratory.

  15. Lithologic Control on Secondary Clay Mineral Formation in the Valles Caldera, New Mexico

    NASA Astrophysics Data System (ADS)

    Caylor, E.; Rasmussen, C.; Dhakal, P.

    2015-12-01

    Understanding the transformation of rock to soil is central to landscape evolution and ecosystem function. The objective of this study was to examine controls on secondary mineral formation in a forested catchment in the Catalina-Jemez CZO. We hypothesized landscape position controls the type of secondary minerals formed in that well-drained hillslopes favor Si-poor secondary phases such as kaolinite, whereas poorly drained portions of the landscape that collect solutes from surrounding areas favor formation of Si-rich secondary phases such as smectite. The study focused on a catchment in Valles Caldera in northern New Mexico where soils are derived from a mix of rhyolitic volcanic material, vegetation includes a mixed conifer forest, and climate is characterized by a mean annual precipitation of ~800 mm yr-1 and mean annual temperature of 4.5°C. Soils were collected at the soil-saprolite boundary from three landscape positions, classified as well drained hillslope, poorly drained convergent area, and poorly drained hill slope. Clay fractions were isolated and analyzed using a combination of quantitative and qualitative x-ray diffraction (XRD) analyses and thermal analysis. Quantitative XRD of random powder mounts indicated the presence of both primary phases such as quartz, and alkali and plagioclase feldspars, and secondary phases that include illite, Fe-oxyhydroxides including both goethite and hematite, kaolinite, and smectite. The clay fractions were dominated by smectite ranging from 36-42%, illite ranging from 21-35%, and kaolinite ranging from 1-8%. Qualitative XRD of oriented mounts confirmed the presence of smectite in all samples, with varying degrees of interlayering and interstratification. In contrast to our hypothesis, results indicated that secondary mineral assemblage was not strongly controlled by landscape position, but rather varied with underlying variation in lithology. The catchment is underlain by a combination of porphorytic rhyolite and

  16. Giant pseudoaneurysm on left ventricular posterolateral wall with an orifice between papillary muscles.

    PubMed

    Saito, Tomohiro; Solowjowa, Natalia; Hetzer, Roland; Knosalla, Christoph

    2014-11-01

    A left ventricular pseudoaneurysm develops when myocardial rupture is contained by the pericardium. Although left ventricular pseudoaneurysm has been a topic of discussion since the pioneering days of open heart surgery, it still remains a technical challenge in reconstructive cardiac surgery. Reoperation following pseudoaneurysm repair is also frequent. We report surgical treatment in two patients with a pseudoaneurysm on the left ventricular posterolateral wall. The pseudoaneurysm and left ventricular cavity communicated at a point just between the anterolateral and posteromedial papillary muscle attachments. Such a manifestation is highly infrequent but potentially lethal. During aneurysmectomy, special attention was paid to avoid the development of mitral regurgitation because the papillary muscle geometry changes after removal of the pseudoaneurysm. In both cases, surgical decision-making was facilitated by preoperative assessment using electrocardiographic-gated multislice computed tomography.

  17. Secondary organic aerosol formation from ozone-initiated reactions with nicotine and secondhand tobacco smoke

    NASA Astrophysics Data System (ADS)

    Sleiman, Mohamad; Destaillats, Hugo; Smith, Jared D.; Liu, Chen-Lin; Ahmed, Musahid; Wilson, Kevin R.; Gundel, Lara A.

    2010-11-01

    We used controlled laboratory experiments to evaluate the aerosol-forming potential of ozone reactions with nicotine and secondhand smoke. Special attention was devoted to real-time monitoring of the particle size distribution and chemical composition of SOA as they are believed to be key factors determining the toxicity of SOA. The experimental approach was based on using a vacuum ultraviolet photon ionization time-of-flight aerosol mass spectrometer (VUV-AMS), a scanning mobility particle sizer (SMPS) and off-line thermal desorption coupled to mass spectrometry (TD-GC-MS) for gas-phase byproducts analysis. Results showed that exposure of SHS to ozone induced the formation of ultrafine particles (<100 nm) that contained high molecular weight nitrogenated species ( m/ z 400-500), which can be due to accretion/acid-base reactions and formation of oligomers. In addition, nicotine was found to contribute significantly (with yields 4-9%) to the formation of secondary organic aerosol through reaction with ozone. The main constituents of the resulting SOA were tentatively identified and a reaction mechanism was proposed to elucidate their formation. These findings identify a new component of thirdhand smoke that is associated with the formation of ultrafine particles (UFP) through oxidative aging of secondhand smoke. The significance of this chemistry for indoor exposure and health effects is highlighted.

  18. A model of formative assessment practice in secondary science classrooms using an audience response system

    NASA Astrophysics Data System (ADS)

    Shirley, Melissa L.

    Formative assessment involves the probing of students' ideas to determine their level of understanding during the instructional sequence. Often conceptualized as a cycle, formative assessment consists of the teacher posing an instructional task to students, collecting data about student understanding, and engaging in follow-up strategies such as clarifying student understanding and adjusting instruction to meet learning needs. Despite having been shown to increase student achievement in a variety of classroom settings, formative assessment remains a relative weak area of teacher practice. Methods that enhance formative assessment strategies may therefore have a positive effect on student achievement. Audience response systems comprise a broad category of technologies that support richer classroom interaction and have the potential to facilitate formative assessment. Results from a large national research study, Classroom Connectivity in Promoting Mathematics and Science Achievement (CCMS), show that students in algebra classrooms where the teacher has implemented a type of audience response system experience significantly higher achievement gains compared to a control group. This suggests a role for audience response systems in promoting rich formative assessment. The importance of incorporating formative assessment strategies into regular classroom practice is widely recognized. However, it remains challenging to identify whether rich formative assessment is occurring during a particular class session. This dissertation uses teacher interviews and classroom observations to develop a fine-grained model of formative assessment in secondary science classrooms employing a type of audience response system. This model can be used by researchers and practitioners to characterize components of formative assessment practice in classrooms. A major component of formative assessment practice is the collection and aggregation of evidence of student learning. This dissertation

  19. Postpyelolithotomy Renal Artery Pseudoaneurysm Management with Percutaneous Thrombin Injection: A Case Report

    SciTech Connect

    Gupta, Vivek Galwa, Ramprakash; Khandelwal, N.; Bapuraj, J. R.

    2008-03-15

    Renal artery pseudoaneurysm leading to life-threatening hematuria can occur after a surgical procedure such as pyelolithotomy, albeit rarely. With recent advances in transarterial embolization techniques, this minimally invasive procedure has become the treatment of choice, replacing surgery. We present a case of massive hematuria due to renal artery pseudoaneurysm developing after pyelolithotomy that was managed with percutaneus thrombin injection directly into the pseudoaneurysm.

  20. Hemobilia Due to Cystic Artery Pseudoaneurysm: A Rare Late Complication of Laparoscopic Cholecystectomy

    PubMed Central

    Darcy, Michael D.; Kushnir, Vladimir M.

    2017-01-01

    We discuss a patient with late presentation of hemobilia following cholecystectomy, which is unusual because pseudoaneurysm caused by vascular injury during surgery typically presents soon after surgery. Endoscopic retrograde cholangiopancreatography revealed a large blood clot arising from the biliary orifice with subsequent computed tomography angiography diagnosing a large pseudoaneurysm in the region of the cystic artery adjacent to the cholecystectomy clips. Embolization was performed via direct percutaneous puncture of the pseudoaneurysm. PMID:28331877

  1. Pseudoaneurysm of the Inferior Epigastric Artery Successfully Treated by Ultrasound-guided Compression

    SciTech Connect

    Takase, Kei Kazama, Takuro; Abe, Kayoko; Chiba, Yoshihiro; Saito, Haruo; Takahashi, Shoki

    2004-09-15

    An 82-year-old woman underwent right hemicolectomy by median laparotomy. Two weeks later, a pulsatile mass was found at the left side of the surgical wound, which was diagnosed as pseudoaneurysm of the inferior epigastric artery by color Doppler US and CT. The pseudoaneurysm was successfully treated by US-guided compression of the neck of the aneurysm for 30 minutes. US-guided compression should be considered the treatment of choice for postsurgical pseudoaneurysm of the inferior epigastric artery.

  2. [ROLE OF LEPTIN IN THE FORMATION OF SECONDARY AMENORRHEA IN ADOLESCENT GIRLS].

    PubMed

    Levenets, S A; Nachotova, T A; Kashkalda, D A

    2015-01-01

    In order to understand the role of leptin in the formation of secondary amenorrhea (SA) during puberty, 78 girls aged from 13 to 17 years with SA and 74 girls of the same age with regular menstrual cycle have been examined with the estimation of body mass index (BMI) and hormonal/metabolic state. The obtained data show a strong connection between leptin level, BMI and parameters of energetic metabolic state (insulin; HOMA index); regression analysis results indicated the participation of leptin in steroidogenesis. Odds ratio (OR) values indicated an important role of leptin in the formation of SA during body weight deficit and normal BMI. It has been found that various clinical types of SA have different patterns of leptin influence.

  3. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-08-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios (3-8), the SOA yields from isoprene high-NOx photooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  4. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-04-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios, the SOA yields from isoprene high-NOxphotooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  5. Composition and secondary formation of fine particulate matter in the Salt Lake Valley: winter 2009.

    PubMed

    Kuprov, Roman; Eatough, Delbert J; Cruickshank, Tyler; Olson, Neal; Cropper, Paul M; Hansen, Jaron C

    2014-08-01

    Under the National Ambient Air Quality Standards (NAAQS), put in place as a result of the Clean Air Amendments of 1990, three regions in the state of Utah are in violation of the NAAQS for PM10 and PM2.5 (Salt Lake County, Ogden City, and Utah County). These regions are susceptible to strong inversions that can persist for days to weeks. This meteorology, coupled with the metropolitan nature of these regions, contributes to its violation of the NAAQS for PM during the winter. During January-February 2009, 1-hr averaged concentrations of PM10-2.5, PM2.5, NO(x), NO2, NO, O3, CO, and NH3 were measured. Particulate-phase nitrate, nitrite, and sulfate and gas-phase HONO, HNO3, and SO2 were also measured on a 1-hr average basis. The results indicate that ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited. Overall, the lower boundary layer in the Salt Lake Valley appears to be oxidant and volatile organic carbon (VOC) limited with respect to ozone formation. The most effective way to reduce ammonium nitrate secondary particle formation during the inversions period is to reduce NO(x) emissions. However, a decrease in NO(x) will increase ozone concentrations. A better definition of the complete ozone isopleths would better inform this decision. Implications: Monitoring of air pollution constituents in Salt Lake City, UT, during periods in which PM2.5 concentrations exceeded the NAAQS, reveals that secondary aerosol formation for this region is NO(x) limited. Therefore, NO(x) emissions should be targeted in order to reduce secondary particle formation and PM2.5. Data also indicate that the highest concentrations of sulfur dioxide are associated with winds from the north-northwest, the location of several small refineries.

  6. Secondary organic aerosol formation from the ozonolysis of 2-carene and 3-carene

    NASA Astrophysics Data System (ADS)

    Mellouki, A.; Chen, H.; Bernard, F.; Cazaunau, M.; Grosselin, B.; Daele, V.; Chen, J.

    2013-12-01

    The atmospheric degradation of terpenes in the remote areas such as those with coniferous forests is known to lead to the formation and growth of atmospheric new particles. 2-carene and 3-carene have been reported to be present in number of such areas. Hence, their oxidation may represent an important source of secondary organic aerosols in some specific regions. 2-carene and 3-carene possess a structure of endocyclic double bonds which make them reactive toward ozone under atmospheric conditions. We have conducted a study on the reactions of ozone with 2-carene and 3-carene using a flow reactor dedicated to the investigation of secondary organic aerosol (SOA) formation. The reactor is equipped with an ozone generator and a movable injector which allows the reaction to occur within a short time range (typically 17 - 48 seconds). This enables us to investigate the initial steps of the SOA formation. In a first series of experiments, we have determined the rate constant for the reaction of ozone with 3-carene under pseudo-first-order conditions. The rate constant value measured was 3.8 x 10-17 molecule-1s-1, at 298 K, in agreement with the literatures and simulation chamber experiments. We have then investigated the SOA formation from the ozonolysis of 2-carene and 3-carene. By adjusting the residence time and initial concentration of carenes and ozone, number concentration of SOA have been measured for short reactions times and low concentrations of reactants. Nucleation thresholds of 2-carene and 3-carene were extracted from the plots of log N = f(Δ[Carenes]).

  7. Formation of hydroxyl radicals from photolysis of secondary organic aerosol material

    NASA Astrophysics Data System (ADS)

    Badali, K. M.; Zhou, S.; Aljawhary, D.; Antiñolo, M.; Chen, W. J.; Lok, A.; Mungall, E.; Wong, J. P. S.; Zhao, R.; Abbatt, J. P. D.

    2015-07-01

    This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both α-pinene and limonene SOA, are measured from the formation rate of p-hydroxybenzoic acid as measured using offline HPLC analysis. To evaluate whether the OH is formed by photolysis of H2O2 or organic hydroperoxides (ROOH), the peroxide content of the SOA was measured using the horseradish peroxidase-dichlorofluorescein (HRP-DCF) assay, which was calibrated using H2O2. The OH formation rates from SOA are 5 times faster than from the photolysis of H2O2 solutions whose concentrations correspond to the peroxide content of the SOA solutions, assuming that the HRP-DCF signal arises from H2O2 alone. The higher rates of OH formation from SOA are likely due to ROOH photolysis, but we cannot rule out a contribution from secondary processes as well. This result is substantiated by photolysis experiments conducted with t-butyl hydroperoxide and cumene hydroperoxide which produce over 3 times more OH than photolysis of equivalent concentrations of H2O2. Relative to the peroxide level in the SOA and assuming that the peroxides drive most of the ultraviolet absorption, the quantum yield for OH generation from α-pinene SOA is 0.8 ± 0.4. This is the first demonstration of an efficient photolytic source of OH in SOA, one that may affect both cloud water and aerosol chemistry.

  8. Endovascular Treatment of a Vertebral Artery Pseudoaneurysm Following Posterior C1-C2 Transarticular Screw Fixation

    SciTech Connect

    Mendez, Jose C. Gonzalez-Llanos, Francisco

    2005-01-15

    We present a case of vertebral artery pseudoaneurysm after a posterior C1-C2 transarticular screw fixation procedure that was effectively treated with endovascular coil occlusion. Vertebral artery pseudoaneurysm complicating posterior C1-C2 transarticular fixation is extremely rare, with only one previous case having been reported previously. Endovascular occlusion is better achieved in the subacute phase of the pseudoaneurysm, when the wall of the pseudoaneurysm has matured and stabilized. Further follow-up angiographies are mandatory in order to confirm that there is no recurrence of the lesion.

  9. Interventional Radiology in the Management of Visceral Artery Pseudoaneurysms: A Review of Techniques and Embolic Materials

    PubMed Central

    Venkatesh, Hosur Ananthashayana; Gamanagatti, Shivanand; Garg, Pramod; Srivastava, Deep Narayan

    2016-01-01

    Visceral artery pseudoaneurysms occur mostly as a result of inflammation and trauma. Owing to high risk of rupture, they require early treatment to prevent lethal complications. Knowledge of the various approaches of embolization of pseudoaneurysms and different embolic materials used in the management of visceral artery pseudoaneurysms is essential for successful and safe embolization. We review and illustrate the endovascular, percutaneous and endoscopic ultrasound techniques used in the treatment of visceral artery pseudoaneurysm and briefly discuss the embolic materials and their benefits and risks. PMID:27134524

  10. Bare Stent Implantation in Iatrogenic Dissecting Pseudoaneurysm of the Superior Mesenteric Artery

    SciTech Connect

    Kutlu, Ramazan Ara, Cengiz; Sarac, Kaya

    2007-02-15

    Iatrogenic arterial dissection leading to the development of dissecting pseudoaneurysms of the superior mesenteric artery (SMA) is a rare complication of angiography. Surgical and endovascular treatment options exist for this important condition. We report a case of bare stent implantation in dissecting pseudoaneurysm of the SMA that developed after angiography in a patient with acute mesenteric ischemia. Although it is rarely published, iatrogenic arterial dissection causing pseudoaneurysm can occur after diagnostic and interventional angiography. Bare stent implantation in dissecting pseudoaneurysm of the SMA could be an advantageous endovascular treatment option in selected cases due its to potential preservation of important side branches of the SMA.

  11. Pseudoaneurysm of the Common Carotid Artery in an Infant due to Swallowed Fish Bone

    PubMed Central

    Jean Roger, Moulion Tapouh; Marcus, Fokou; Emmanuel, Fongang; Boniface, Moifo; Alain Georges, Juimo

    2015-01-01

    Carotid artery pseudoaneurysm is a rare condition, particularly in the paediatric population. Only about 30 cases of carotid artery aneurysms in infants have been published until now. This paper reports the case of a giant pseudoaneurysm of the left common carotid artery due to swallowed fish bone by an 8-year-old boy. This pseudoaneurysm was 5.5 cm transverse-diameter and resulted in severe respiratory distress. It was treated by resection and end-to-end anastomosis with satisfactory outcome after one-year follow-up. To the best of our knowledge, this is the largest carotid artery pseudoaneurysm ever described in children. PMID:26783485

  12. Non-Tuberculous Mycobacterium Induced Pseudoaneurysm of the Common Carotid Artery

    PubMed Central

    Lee, Hae Young; Cho, Seong Ho; Kim, Hyun Su; Moon, Jeong Min; Lee, Sangho; Kim, Jong In

    2016-01-01

    An 81-year-old male patient presented with complaint of a pulsating neck mass. The patient had a previous history of cervical lymphadenopathy by non-tuberculous mycobacterium infection. Rapid growth of the mass on admission and contrast enhanced computed tomography of the neck resulted in a diagnosis of non-tuberculous mycobacterium induced pseudoaneurysm. The patient underwent emergency open repair of the pseudoaneurysm. Pseudoaneurysm of the common carotid artery is regularly reported, but here we report a rare case of non-tuberculous mycobacterium induced pseudoaneurysm of the common carotid artery. PMID:27965926

  13. A secondary antibody format chemiluminescence immunoassay for the determination of estradiol in human serum.

    PubMed

    Xin, Tian-Bing; Chen, Hui; Lin, Zhen; Liang, Shu-Xuan; Lin, Jin-Ming

    2010-09-15

    A competitive immunoassay for estradiol (E2) based on secondary antibody format was established. The donkey anti-rabbit IgG was used as the secondary antibody to coat micro-plates, and the horseradish peroxidase (HRP)-luminol-H(2)O(2) chemiluminescent system with high sensitivity was chosen as the detection system. The addition of sodium trichloroacetate (CCl(3)COONa) in the enzyme buffer as a replaceable packing material can realize directly analysis of E2 in human serum without extraction, which improved reproducibility and resolution of the assay. Additionally, the method showed specific recognition of estrogen, without cross-reaction for the major steroids (estrone (E1), estriol (E3), dihydrotestosterone (DHT), androstenedione, testosterone (T)) commonly found in human serum. The chemiluminescence immunoassay with secondary antibody can be applied to detect E2 with good precision at concentrations as low as 1.48 pg mL(-1). The proposed method has been successfully applied to the determination of E2 in 97 human sera and showed a good correlation compared with the commercially radioimmunoassay (RIA) kit with a correlative coefficient of 0.9881. This method has exhibited great potential in the fabrication of diagnostic kit and can be used in the clinical analysis of E2 in human serum.

  14. Chamber studies to simulate secondary organic aerosol formation from the Deepwater Horizon oil spill

    NASA Astrophysics Data System (ADS)

    Daumit, K. E.; Carrasquillo, A. J.; Cross, E. S.; Hunter, J. F.; Bahreini, R.; Middlebrook, A. M.; De Gouw, J. A.; Williams, L. R.; Worsnop, D. R.; Kroll, J. H.

    2011-12-01

    Because atmospheric organic species are generally emitted from a large number of sources, over wide spatial and temporal scales, it is generally challenging to ascribe ambient organic aerosol (OA) to the oxidation of specific secondary organic aerosol (SOA) precursors. However, the Deepwater Horizon (DWH) oil spill (April 20-July 15, 2010), provided the unique circumstance of a large, well-defined source of gas-phase organics introduced into a relatively clean atmosphere. Here we describe a laboratory simulation of SOA formation downwind of the DWH spill, via the oxidation of South Louisiana-light (SL) crude oil by OH radicals in an environmental chamber. Intermediate and semi-volatile fractions of the SL crude oil are vaporized and oxidized by gas-phase OH radicals (formed from the photolysis of HONO). The chemical composition is monitored as a function of OH exposure. When OH exposures are approximately matched, laboratory-generated SOA and OA measured downwind of the oil spill exhibit extremely similar aerosol mass spectra, in strong support of the hypothesis that the OA measured downwind of the DWH oil spill was secondary in nature. More generally, this agreement indicates that in cases when SOA precursors are well-constrained, chamber experiments can reasonably reproduce key properties of ambient OA. Results of chamber studies on sub-fractions of the SL crude oil, aimed at identifying the classes of oil components most responsible for SOA formation, will be discussed.

  15. Modeling the influence of alkane molecular structure on secondary organic aerosol formation.

    PubMed

    Aumont, Bernard; Camredon, Marie; Mouchel-Vallon, Camille; La, Stéphanie; Ouzebidour, Farida; Valorso, Richard; Lee-Taylor, Julia; Madronich, Sasha

    2013-01-01

    Secondary Organic Aerosols (SOA) production and ageing is a multigenerational oxidation process involving the formation of successive organic compounds with higher oxidation degree and lower vapor pressure. Intermediate Volatility Organic Compounds (IVOC) emitted to the atmosphere are expected to be a substantial source of SOA. These emitted IVOC constitute a complex mixture including linear, branched and cyclic alkanes. The explicit gas-phase oxidation mechanisms are here generated for various linear and branched C10-C22 alkanes using the GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) and SOA formation is investigated for various homologous series. Simulation results show that both the size and the branching of the carbon skeleton are dominant factors driving the SOA yield. However, branching appears to be of secondary importance for the particle oxidation state and composition. The effect of alkane molecular structure on SOA yields appears to be consistent with recent laboratory observations. The simulated SOA composition shows, however, an unexpected major contribution from multifunctional organic nitrates. Most SOA contributors simulated for the oxidation of the various homologous series are far too reduced to be categorized as highly oxygenated organic aerosols (OOA). On a carbon basis, the OOA yields never exceeded 10% regardless of carbon chain length, molecular structure or ageing time. This version of the model appears clearly unable to explain a large production of OOA from alkane precursors.

  16. Secondary organic aerosol formation from cyclohexene ozonolysis in the presence of water vapor and dissolved salts

    NASA Astrophysics Data System (ADS)

    Warren, Bethany; Malloy, Quentin G. J.; Yee, Lindsay D.; Cocker, David R.

    A series of 90 experiments were conducted in the UC Riverside/CE-CERT environmental chamber to evaluate the impact of water vapor and dissolved salts on secondary organic aerosol formation for cyclohexene ozonolysis. Water vapor (low - 30 ± 2% RH, medium - 46 ± 2% RH, high - 63 ± 2% RH) was found to directly participate in the atmospheric chemistry altering the composition of the condensing species, thus increasing total organic aerosol formation by ˜22% as compared to the system under dry (<0.1% RH) conditions. Hygroscopicity measurements also indicate that the organic aerosol composition is altered in the presence of gaseous water. These results are consistent with water vapor reacting with the crigee intermediate in the gas phase resulting in increased aldehyde formation. The addition of dissolved salts ((NH 4) 2SO 4, NH 4HSO 4, CaCl 2, NaCl) had minimal effect; only the (NH 4) 2SO 4 and NaCl were found to significantly impact the system with ˜10% increase in total organic aerosol formation. These results indicate that the organics may be partitioning to an outer organic shell as opposed to into the aqueous salt. Hygroscopicity measurements indicate that the addition of salts does not alter the aerosol composition for the dry or water vapor system.

  17. N-nitrosamines formation from secondary amines by nitrogen fixation on the surface of activated carbon.

    PubMed

    Padhye, Lokesh P; Hertzberg, Benjamin; Yushin, Gleb; Huang, Ching-Hua

    2011-10-01

    Our previous study demonstrated that many commercial activated carbon (AC) particles may catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. Because of the widespread usage of AC materials in numerous analytical and environmental applications, it is imperative to understand the reaction mechanism responsible for formation of nitrosamine on the surface of ACs to minimize their occurrence in water treatment systems and during analytical methods employing ACs. The study results show that the AC-catalyzed nitrosamine formation requires both atmospheric oxygen and nitrogen. AC's surface reactive sites react with molecular oxygen to form reactive oxygen species (ROS), which facilitate fixation of molecular nitrogen on the carbon surfaces to generate reactive nitrogen species (RNS) likely nitrous oxide and hydroxylamine that can react with adsorbed amines to form nitrosamines. AC's properties play a crucial role as more nitrosamine formation is associated with carbon surfaces with higher surface area, more surface defects, reduced surface properties, higher O(2) uptake capacity, and higher carbonyl group content. This study is a first of its kind on the nitrosamine formation mechanism involving nitrogen fixation on AC surfaces, and the information will be useful for minimization of nitrosamines in AC-based processes.

  18. Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

    SciTech Connect

    Wang, Wei; Li, Eryang; Porth, Ilga; Chen, Jin-Gui; Mansfield, Shawn D.; Douglas, Carl J.; Wang, Shucai

    2016-02-02

    Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter, PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.

  19. Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

    DOE PAGES

    Wang, Wei; Li, Eryang; Porth, Ilga; ...

    2016-02-02

    Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

  20. Secondary chaotic terrain formation in the higher outflow channels of southern circum-Chryse, Mars

    USGS Publications Warehouse

    Rodriguez, J.A.P.; Kargel, J.S.; Tanaka, K.L.; Crown, D.A.; Berman, D.C.; Fairen, A.G.; Baker, V.R.; Furfaro, R.; Candelaria, P.; Sasaki, S.

    2011-01-01

    Higher outflow channel dissection in the martian region of southern circum-Chryse appears to have extended from the Late Hesperian to the Middle Amazonian Epoch. These outflow channels were excavated within the upper 1. km of the cryolithosphere, where no liquid water is expected to have existed during these geologic epochs. In accordance with previous work, our examination of outflow channel floor morphologies suggests the upper crust excavated by the studied outflow channels consisted of a thin (a few tens of meters) layer of dry geologic materials overlying an indurated zone that extends to the bases of the investigated outflow channels (1. km in depth). We find that the floors of these outflow channels contain widespread secondary chaotic terrains (i.e., chaotic terrains produced by the destruction of channel-floor materials). These chaotic terrains occur within the full range of outflow channel dissection and tend to form clusters. Our examination of the geology of these chaotic terrains suggests that their formation did not result in the generation of floods. Nevertheless, despite their much smaller dimensions, these chaotic terrains are comprised of the same basic morphologic elements (e.g., mesas, knobs, and smooth deposits within scarp-bound depressions) as those located in the initiation zones of the outflow channels, which suggests that their formation must have involved the release of ground volatiles. We propose that these chaotic terrains developed not catastrophically but gradually and during multiple episodes of nested surface collapse. In order to explain the formation of secondary chaotic terrains within zones of outflow channel dissection, we propose that the regional Martian cryolithosphere contained widespread lenses of volatiles in liquid form. In this model, channel floor collapse and secondary chaotic terrain formation would have taken place as a consequence of instabilities arising during their exhumation by outflow channel dissection

  1. Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

    NASA Astrophysics Data System (ADS)

    Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

    2016-04-01

    Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m-Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts

  2. Secondary Reaction Zone Formations in coated Ni-base Single Crystal Superalloys

    NASA Astrophysics Data System (ADS)

    Suzuki, A.; Rae, C. M. F.

    2009-05-01

    Ruthenium (Ru) has been added to the latest 4th Generation Ni-base superalloys to improve phase stability and modify creep life. Various coatings are routinely applied to these advanced alloys to protect the turbine blade at elevated temperature, however, this creates several problems such as the precipitation of brittle Topologically Close-Packed (TCP) phases and the formation of Secondary Reaction Zones (SRZ). The SRZ forms under the plat-aluminized coating of turbine blades and consists of γ, γ and TCP phases growing into substrate by the migration of high-angle grain boundaries. Surface residual stress and chemical super-saturation of alloying elements are associated to SRZ formation. In the thin sections of high-pressure turbine blades this is critical in determining blade performance and longevity. It is essential to know how Ru additions affect coating and SRZ morphologies during exposure. In this study, we focus on the effects of three variables on the SRZ formation: Ru concentration, alloy composition in Ru-containing alloys and surface finish. A series of Platinum-Aluminised superalloys containing 2-5wt% Ru and having various surface finishes was studied after isothermal exposure at 1100°C for up to 500h. The alloys were classified into two groups by their distinctive SRZ morphology. At the lowest Ru levels sporadic formation of SRZ was observed, whilst a continuous SRZ was formed in the higher Ru alloys. EBSD analysis revealed that the latter group have a higher nucleation rate of individual SRZ grains and also showed more rapid SRZ growth. The precipitation of TCPs in the substrate also inhibited the growth of the SRZ towards the end of the exposure further reducing the penetration of the SRZ into the substrate. It is concluded that Ru-additions to Ni-base superalloys are effective in impeding TCP phase formation in the substrate, but increase both the extent and the rate of SRZ formation beneath coating.

  3. Formation of secondary organic aerosol and oligomers from the ozonolysis of enol ethers

    NASA Astrophysics Data System (ADS)

    Sadezky, A.; Chaimbault, P.; Mellouki, A.; Römpp, A.; Winterhalter, R.; Le Bras, G.; Moortgat, G. K.

    2006-10-01

    Formation of secondary organic aerosol has been observed in the gas phase ozonolysis of a series of enol ethers, among them several alkyl vinyl ethers (AVE, ROCH=CH2), such as ethyl, propyl, n-butyl, iso-butyl, t-butyl vinyl ether, and ethyl propenyl ether (EPE, C2H5OCH=CHCH3). The ozonolysis has been studied in a 570 l spherical glass reactor at ambient pressure (730 Torr) and room temperature (296 K). Gas phase reaction products were investigated by in-situ FTIR spectroscopy, and secondary organic aerosol (SOA) formation was monitored by a scanning mobility particle sizer (SMPS). The chemical composition of the formed SOA was analysed by a hybrid mass spectrometer using electrospray ionization (ESI). The main stable gas phase reaction product is the respective alkyl formate ROC(O)H, formed with yields of 60 to 80%, implying that similar yields of the corresponding excited Criegee Intermediates (CI) CH2O2 for the AVE and CH3CHO2 for EPE are generated. Measured SOA yields are between 2 to 4% for all enol ethers. Furthermore, SOA formation is strongly reduced or suppressed by the presence of an excess of formic acid, which acts as an efficient CI scavenger. Chemical analysis of the formed SOA by ESI(+)/MS-TOF allows to identify oligomeric compounds in the mass range 200 to 800 u as its major constituents. Repetitive chain units are identified as CH2O2 (mass 46) for the AVE and C2H4O2 (mass 60) for EPE and thus have the same chemical compositions as the respective major Criegee Intermediates formed during ozonolysis of these ethers. The oligomeric structure and chain unit identity are confirmed by HPLC/ESI(+)/MS-TOF and ESI(+)/MS/MS-TOF experiments, whereby successive and systematic loss of a fragment with mass 46 for the AVE (and mass 60 for EPE) is observed. It is proposed that the oligomer has the following basic structure of an oligoperoxide, -[CH(R)-O-O]n-, where R=H for the AVE and R=CH3 for the EPE. Oligoperoxide formation is thus suggested to be another, so

  4. Formation of secondary organic aerosol and oligomers from the ozonolysis of enol ethers

    NASA Astrophysics Data System (ADS)

    Sadezky, A.; Chaimbault, P.; Mellouki, A.; Römpp, A.; Winterhalter, R.; Le Bras, G.; Moortgat, G. K.

    2006-06-01

    Formation of secondary organic aerosol has been observed in the gas phase ozonolysis of a series of enol ethers, among them several alkyl vinyl ethers (AVE, ROCH=CH2), such as ethyl, propyl, n-butyl, iso-butyl, t-butyl vinyl ether, and ethyl propenyl ether (EPE, C2H5OCH=CHCH3). The ozonolysis has been studied in a 570 l spherical glass reactor at atmospheric pressure (730 Torr) and temperature (296 K). Gas phase reaction products were investigated by in-situ FTIR spectroscopy, and secondary organic aerosol (SOA) formation was monitored by a scanning mobility particle sizer (SMPS). The chemical composition of the formed SOA was analysed by a hybrid mass spectrometer using electrospray ionization (ESI). The main stable gas phase reaction product is the respective alkyl formate ROC(O)H, formed with yields of 60 to 80%, implying that similar yields of the corresponding Criegee Intermediates (CI) CH2O2 for the AVE and CH3CHO2 for EPE are generated. Measured SOA yields are between 2 to 4% for all enol ethers. Furthermore, SOA formation is strongly reduced or suppressed by the presence of an excess of formic acid, which acts as an efficient CI scavenger. Chemical analysis of the formed SOA by ESI(+)/MS-TOF allows to identify oligomeric compounds in the mass range 200 to 800 u as its major constituents. Repetitive chain units are identified as CH2O2 (mass 46) for the AVE and C2H4O2 (mass 60) for EPE and thus have the same chemical compositions as the respective major Criegee Intermediates formed during ozonolysis of these ethers. The oligomeric structure and chain unit identity are confirmed by HPLC/ESI(+)/MS-TOF and ESI(+)/MS/MS-TOF experiments, whereby successive and systematic loss of a fragment with mass 46 for the AVE (and mass 60 for EPE) is observed. It is proposed that the oligomer has the following basic structure of an oligoperoxide, -[CH(R)-O-O]n-, where R=H for the AVE and R=CH3 for the EPE. Oligoperoxide formation is thus suggested to be another, so far

  5. 3rd hand smoking; heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment

    NASA Astrophysics Data System (ADS)

    Petrick, Lauren; Dubowski, Yael

    2010-05-01

    Tobacco smoking is well known as a significant source of primary indoor air pollutants. However, only recently has it been recognized that the impact of Tobacco smoking may continue even after the cigarette has been extinguished (i.e., third hand smoke) due to the effect of indoor surfaces. These surfaces may affect the fate of tobacco smoke in the form of secondary reactions and pollutants, including secondary organic aerosol (SOA) formation. Fourier Transform Infrared spectrometry with Attenuated Total Reflection (FTIR-ATR) in tandem with a Scanning Mobility Particle Sizing (SMPS) system was used to monitor the ozonation of cellulose sorbed nicotine and resulting SOA formation. SOA formation began at onset of ozone introduction ([O3] = 60 ± 5 ppb) with a size distribution of dp ≤ 25 nm, and was determined to be a result of heterogeneous reaction (opposed to homogeneous). SOA yield from reacted surface nicotine was on the order of 10 %. Simultaneous to SOA monitoring, FTIR-ATR spectra showed surface changes in the nicotine film as the reaction progressed, revealing a pseudo first-order surface reaction rate of 0.0026 ± 0.0008 min-1. Identified surface oxidation products included: cotinine, myosmine, methylnicotinamide and nicotyrine. Surface reaction rate was found to be partially inhibited at high relative humidity. Given the toxicity of some of the identified products (e.g., cotinine has shown potential mutagenicity and teratogenicity) and that small particles may contribute to adverse health effects, the present study indicates that exposure to 3rd hand smoke ozonation products may pose additional health risks.

  6. Primary sources and secondary formation of organic aerosols in Beijing, China.

    PubMed

    Guo, Song; Hu, Min; Guo, Qingfeng; Zhang, Xin; Zheng, Mei; Zheng, Jun; Chang, Chih Chung; Schauer, James J; Zhang, Renyi

    2012-09-18

    Ambient aerosol samples were collected at an urban site and an upwind rural site of Beijing during the CAREBEIJING-2008 (Campaigns of Air quality REsearch in BEIJING and surrounding region) summer field campaign. Contributions of primary particles and secondary organic aerosols (SOA) were estimated by chemical mass balance (CMB) modeling and tracer-yield method. The apportioned primary and secondary sources explain 73.8% ± 9.7% and 79.6% ± 10.1% of the measured OC at the urban and rural sites, respectively. Secondary organic carbon (SOC) contributes to 32.5 ± 15.9% of the organic carbon (OC) at the urban site, with 17.4 ± 7.6% from toluene, 9.7 ± 5.4% from isoprene, 5.1 ± 2.0% from α-pinene, and 2.3 ± 1.7% from β-caryophyllene. At the rural site, the secondary sources are responsible for 38.4 ± 14.4% of the OC, with the contributions of 17.3 ± 6.9%, 13.9 ± 9.1%, 5.6 ± 1.9%, and 1.7 ± 1.0% from toluene, isoprene, α-pinene, and β-caryophyllene, respectively. Compared with other regions in the world, SOA in Beijing is less aged, but the concentrations are much higher; between the sites, SOA is more aged and affected by regional transport at the urban site. The high SOA loading in Beijing is probably attributed to the high regional SOC background (~2 μg m(-3)). The toluene SOC concentration is high and comparable at the two sites, implying that some anthropogenic components, at least toluene SOA, are widespread in Beijing and represents a major factor in affecting the regional air quality. The aerosol gaseous precursor concentrations and temperature correlate well with SOA, both affecting SOA formation. The significant SOA enhancement with increasing water uptake and acidification indicates that the aqueous-phase reactions are largely responsible SOA formation in Beijing.

  7. Constraints on Permeability Resulting from Secondary Porosity in the Burns Formation, Meridiani Planum, Mars

    NASA Astrophysics Data System (ADS)

    Perl, S. M.; McLennan, S. M.

    2012-12-01

    Investigations by the MER rover Opportunity of the Burns Formation on the surface and within various craters on Meridiani Planum, using the Rock Abrasion Tool (RAT) and Microscopic Imager (MI), revealed abundant void spaces within abraded sandstone outcrop targets interpreted to have formed by post-depositional mineral dissolution of primary depositional constituents. After deposition, multiple episodic events of groundwater recharge led to these constituents, primarily Mg-sulfates, chlorides, or other soluble ferrous sulfates, being dissolved - leaving behind secondary porosity. Elongate to sheet-like pores are aligned to bedding, but with vertical porous features allowing for connectivity of pore spaces, or throats, throughout much of the exposed stratigraphic section; the section itself being divided into three units in the vicinity of Endurance crater whose boundaries are controlled largely by the former presence of a fluctuating paleo-groundwater table. The boundary separating the Lower and Middle units (Wellington contact) formed as a groundwater-controlled deflation surface whereas the boundary separating the Middle and Upper units (Whatanga contact) is interpreted as a diagenetic front possibly associated with a stagnant water table. The timing, shape, volume, and quantity of secondary pore space provide important constraints on the genesis and history of diagenetic fluid-flow through these sedimentary rocks. Measurements of pore geometries indicate that three distinct pore classes can be defined with varying length/width ratios, shapes, abundances, and stratigraphic position. The infiltration history of these groundwater recharge cycles is likely related to the connectivity of secondary pores. After the original mineral dissolution, the vertical extent of the vadose zone probably decreased as the water table rose higher with each recharge cycle. Secondary pores that have been enlarged have only been found stratigraphically at the Whatanga contact exposed

  8. Chemistry of secondary organic aerosol: Formation and evolution of low-volatility organics in the atmosphere

    NASA Astrophysics Data System (ADS)

    Kroll, Jesse H.; Seinfeld, John H.

    2008-05-01

    Secondary organic aerosol (SOA), particulate matter composed of compounds formed from the atmospheric transformation of organic species, accounts for a substantial fraction of tropospheric aerosol. The formation of low-volatility (semivolatile and possibly nonvolatile) compounds that make up SOA is governed by a complex series of reactions of a large number of organic species, so the experimental characterization and theoretical description of SOA formation presents a substantial challenge. In this review we outline what is known about the chemistry of formation and continuing transformation of low-volatility species in the atmosphere. The primary focus is chemical processes that can change the volatility of organic compounds: (1) oxidation reactions in the gas phase, (2) reactions in the particle phase, and (3) continuing chemistry (in either phase) over several generations. Gas-phase oxidation reactions can reduce volatility by the addition of polar functional groups or increase it by the cleavage of carbon-carbon bonds; key branch points that control volatility are the initial attack of the oxidant, reactions of alkylperoxy (RO2) radicals, and reactions of alkoxy (RO) radicals. Reactions in the particle phase include oxidation reactions as well as accretion reactions, non-oxidative processes leading to the formation of high-molecular-weight species. Organic carbon in the atmosphere is continually subject to reactions in the gas and particle phases throughout its atmospheric lifetime (until lost by physical deposition or oxidized to CO or CO2), implying continual changes in volatility over the timescales of several days. The volatility changes arising from these chemical reactions must be parameterized and included in models in order to gain a quantitative and predictive understanding of SOA formation.

  9. Cloud processing of organic compounds: Secondary organic aerosol and nitrosamine formation

    NASA Astrophysics Data System (ADS)

    Hutchings, James W., III

    Cloud processing of atmospheric organic compounds has been investigated through field studies, laboratory experiments, and numerical modeling. Observational cloud chemistry studies were performed in northern Arizona and fog studies in central Pennsylvania. At both locations, the cloud and fogs showed low acidity due to neutralization by soil dust components (Arizona) and ammonia (Pennsylvania). The field observations showed substantial concentrations (20-5500 ng•L -1) of volatile organic compounds (VOC) in the cloud droplets. The potential generation of secondary organic aerosol mass through the processing of these anthropogenic VOCs was investigated through laboratory and modeling studies. Under simulated atmospheric conditions, in idealized solutions, benzene, toluene, ethylbenzene, and xylene (BTEX) degraded quickly in the aqueous phase with half lives of approximately three hours. The degradation process yielded less volatile products which would contribute to new aerosol mass upon cloud evaporation. However, when realistic cloud solutions containing natural organic matter were used in the experiments, the reaction kinetics decreased with increasing organic carbon content, resulting in half lives of approximately 7 hours. The secondary organic aerosol (SUA) mass formation potential of cloud processing of BTEX was evaluated. SOA mass formation by cloud processing of BTEX, while strongly dependent on the atmospheric conditions, could contribute up to 9% of the ambient atmospheric aerosol mass, although typically ˜1% appears realistic. Field observations also showed the occurrence of N-nitrosodimethylamine (NDMA), a potent carcinogen, in fogs and clouds (100-340 ng•L -1). Laboratory studies were conducted to investigate the formation of NDMA from nitrous acid and dimethylamine in the homogeneous aqueous phase within cloud droplets. While NDMA was produced in the cloud droplets, the low yields (<1%) observed could not explain observational concentrations

  10. Secondary Organic Aerosol (SOA) Formation from Hydroxyl Radical Oxidation and Ozonolysis of Monoterpenes

    NASA Astrophysics Data System (ADS)

    Zhao, Defeng; Kaminski, Martin; Schlag, Patrick; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Haeseler, Rolf; Kiendler-Scharr, Astrid; Rohrer, Franz; Tillmann, Ralf; Wang, Mingjin; Wegner, Robert; Wahner, Andreas; Mentel, Thomas

    2014-05-01

    Hydroxyl radical (OH) oxidation and ozonolysis are the two major pathways of daytime biogenic volatile organic compounds (VOCs) oxidation and secondary organic aerosol (SOA) formation. The pure OH oxidation of monoterpenes, an important biogenic VOC class, has seldom been investigated. In order to elucidate the importance of the reaction pathyways of the OH oxidation and ozonolysis and their roles in particle formation and growth, we investigated the particle formation of several common monoterpenes (alpha-pinene, beta-pinene, and limonene) in the large atmosphere simulation chamber SAPHIR in Juelich, Germany. The experiments were conducted for both OH dominant and pure ozonolysis case (in the presence of CO as OH scavenger) at ambient relevant conditions (low OA, low VOC and low NOx concentration). OH and ozone (O3) concentrations were measured so that the oxidation rates of OH and O3 with precursors were quantified. The particle formation and growth, aerosol yield, multi-generation reaction process and aerosol composition were analyzed. Pure ozonolysis generated a large amount of particles indicating ozonolysis plays an important role in particle formation as well as OH oxidation. In individual experiments, particle growth rates did not necessarily correlate with OH or O3 oxidation rates. However, comparing the growth rates at similar OH or O3 oxidation rates shows that generally, OH oxidation and ozonolysis have similar efficiency in particle growth. Multi-generation products are shown to be important in the OH oxidation experiment based on aerosol yield "growth curve" (Ng et al., 2006). The reaction process of OH oxidation experiments was analyzed as a function of OH dose to elucidate the role of functionalization and fragmentation. A novel analysis was developed to link the particle formation with the reaction with OH, which was also used to examine the role of functionalization and fragmentation in the particle formation by OH oxidation. These analyses show

  11. Laboratory studies on secondary organic aerosol formation from crude oil vapors.

    PubMed

    Li, R; Palm, B B; Borbon, A; Graus, M; Warneke, C; Ortega, A M; Day, D A; Brune, W H; Jimenez, J L; de Gouw, J A

    2013-01-01

    Airborne measurements of aerosol composition and gas phase compounds over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico in June 2010 indicated the presence of high concentrations of secondary organic aerosol (SOA) formed from organic compounds of intermediate volatility. In this work, we investigated SOA formation from South Louisiana crude oil vapors reacting with OH in a Potential Aerosol Mass flow reactor. We use the dependence of evaporation time on the saturation concentration (C*) of the SOA precursors to separate the contribution of species of different C* to total SOA formation. This study shows consistent results with those at the DWH oil spill: (1) organic compounds of intermediate volatility with C* = 10(5)-10(6) μg m(-3) contribute the large majority of SOA mass formed, and have much larger SOA yields (0.37 for C* = 10(5) and 0.21 for C* = 10(6) μg m(-3)) than more volatile compounds with C*≥10(7) μg m(-3), (2) the mass spectral signature of SOA formed from oxidation of the less volatile compounds in the reactor shows good agreement with that of SOA formed at DWH oil spill. These results also support the use of flow reactors simulating atmospheric SOA formation and aging.

  12. Substantial secondary organic aerosol formation in a coniferous forest: observations of both day- and nighttime chemistry

    NASA Astrophysics Data System (ADS)

    Lee, Alex K. Y.; Abbatt, Jonathan P. D.; Leaitch, W. Richard; Li, Shao-Meng; Sjostedt, Steve J.; Wentzell, Jeremy J. B.; Liggio, John; Macdonald, Anne Marie

    2016-06-01

    Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region in Whistler, British Columbia. A largely biogenic aerosol growth episode was observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas-particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 arises from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is likely less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22-33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol. Using f91 to evaluate BSOA formation pathways in this unpolluted, forested region, heterogeneous oxidation of BSOA-1 is a minor production pathway of BSOA-2.

  13. Formation and evolution of molecular products in α-pinene secondary organic aerosol.

    PubMed

    Zhang, Xuan; McVay, Renee C; Huang, Dan D; Dalleska, Nathan F; Aumont, Bernard; Flagan, Richard C; Seinfeld, John H

    2015-11-17

    Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58-72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA.

  14. Formation and evolution of molecular products in α-pinene secondary organic aerosol

    PubMed Central

    Zhang, Xuan; McVay, Renee C.; Huang, Dan D.; Dalleska, Nathan F.; Aumont, Bernard; Flagan, Richard C.; Seinfeld, John H.

    2015-01-01

    Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58–72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA. PMID:26578760

  15. Impact of NOx on secondary organic aerosol (SOA) formation from β-pinene photooxidation

    NASA Astrophysics Data System (ADS)

    Sarrafzadeh, Mehrnaz; Pullinen, Iida; Springer, Monika; Kleist, Einhard; Tillmann, Ralf; Mentel, Thomas F.; Kiendler-Scharr, Astrid; Hastie, Donald R.; Wildt, Jürgen

    2016-04-01

    Secondary organic aerosols (SOA) generated from atmospheric oxidation of volatile organics contributes substantially to the global aerosol load. It has been shown that odd nitrogen (NOx) has a significant influence on the formation of this SOA. In this study, we investigated SOA formation from β-pinene photooxidation in the Jülich Plant Atmosphere Chamber (JPAC) under varying NOx conditions. At higher-NOx levels, the SOA yield was significantly suppressed by increasing the NOx concentration. However at lower-NOx levels the opposite trend, an increase in SOA with increasing NOx concentration, was observed. This increase was likely due to the increased OH concentration in the stirred flow reactor. By holding the OH concentration constant for all experiments we removed the potential effect of OH concentration on SOA mass growth. In this case increasing the NOx concentration only decreased the SOA yield. In addition, the impact of NOx on SOA formation was explored in the presence of ammonium sulfate seed aerosols. This suggested that SOA yield was only slightly suppressed under increasing NOx concentrations when seed aerosol was present.

  16. Impacts of Sulfate Seed Acidity and Water Content on Isoprene Secondary Organic Aerosol Formation.

    PubMed

    Wong, Jenny P S; Lee, Alex K Y; Abbatt, Jonathan P D

    2015-11-17

    The effects of particle-phase water and the acidity of pre-existing sulfate seed particles on the formation of isoprene secondary organic aerosol (SOA) was investigated. SOA was generated from the photo-oxidation of isoprene in a flow tube reactor at 70% relative humidity (RH) and room temperature in the presence of three different sulfate seeds (effloresced and deliquesced ammonium sulfate and ammonium bisulfate) under low NOx conditions. High OH exposure conditions lead to little isoprene epoxydiol (IEPOX) SOA being generated. The primary result is that particle-phase water had the largest effect on the amount of SOA formed, with 60% more SOA formation occurring with deliquesced ammonium sulfate seeds as compared to that on effloresced ones. The additional organic material was highly oxidized. Although the amount of SOA formed did not exhibit a dependence on the range of seed particle acidity examined, perhaps because of the low amount of IEPOX SOA, the levels of high-molecular-weight material increased with acidity. While the uptake of organics was partially reversible under drying, the results nevertheless indicate that particle-phase water enhanced the amount of organic aerosol material formed and that the RH cycling of sulfate particles may mediate the extent of isoprene SOA formation in the atmosphere.

  17. Effect of Pellet Boiler Exhaust on Secondary Organic Aerosol Formation from α-Pinene.

    PubMed

    Kari, Eetu; Hao, Liqing; Yli-Pirilä, Pasi; Leskinen, Ari; Kortelainen, Miika; Grigonyte, Julija; Worsnop, Douglas R; Jokiniemi, Jorma; Sippula, Olli; Faiola, Celia L; Virtanen, Annele

    2017-02-07

    Interactions between anthropogenic and biogenic emissions, and implications for aerosol production, have raised particular scientific interest. Despite active research in this area, real anthropogenic emission sources have not been exploited for anthropogenic-biogenic interaction studies until now. This work examines these interactions using α-pinene and pellet boiler emissions as a model test system. The impact of pellet boiler emissions on secondary organic aerosol (SOA) formation from α-pinene photo-oxidation was studied under atmospherically relevant conditions in an environmental chamber. The aim of this study was to identify which of the major pellet exhaust components (including high nitrogen oxide (NOx), primary particles, or a combination of the two) affected SOA formation from α-pinene. Results demonstrated that high NOx concentrations emitted by the pellet boiler reduced SOA yields from α-pinene, whereas the chemical properties of the primary particles emitted by the pellet boiler had no effect on observed SOA yields. The maximum SOA yield of α-pinene in the presence of pellet boiler exhaust (under high-NOx conditions) was 18.7% and in the absence of pellet boiler exhaust (under low-NOx conditions) was 34.1%. The reduced SOA yield under high-NOx conditions was caused by changes in gas-phase chemistry that led to the formation of organonitrate compounds.

  18. Impact of Propene on Secondary Organic Aerosol Formation from m-Xylene

    SciTech Connect

    Song, Chen; Na, Kwangsam; Warren, Bethany; Malloy, Quentin; Cocker, David R.

    2007-10-15

    Propene is widely used in smog chamber experiments to increase the hydroxyl radical (OH) level based on the assumption that the formation of secondary organic aerosol (SOA) from parent hydrocarbon is unaffected. A series ofm-xylene/NOx photooxidation experiments were conducted in the presence of propene in the University of California CECERT atmospheric chamber facility. The experimental data are compared with previousm-xylene/NOx photooxidation work performed in the same chamber facility in the absence of propene (Song et al. Environ. Sci. Technol. 2005, 39, 3143-3149). The result shows that, for similar initial conditions, experiments with propene have lower reaction rates of m-xylene than those without propene, which indicates that propene reduces OH in the system. Furthermore, experiments with propene showed more than 15% reduction in SOA yield compared to experiments in the absence of propene. Additional experiments ofm-xylene/NOx with CO showed similar trends of suppressing OH and SOA formation. These results indicate that SOA from m-xylene/NOx photooxidation is strongly dependent on the OH level present, which provides evidence for the critical role of OH in SOA formation from aromatic hydrocarbons.

  19. Secondary organic aerosol formation initiated by α-terpineol ozonolysis in indoor air.

    PubMed

    Yang, Y; Waring, M S

    2016-12-01

    Secondary organic aerosol (SOA) owing to reactive organic gas (ROG) ozonolysis can be an important indoor particle source. However, SOA formation owing to ozonolysis of α-terpineol, which is emitted by consumer product usage and reacts strongly with ozone, has not been systematically quantified. Therefore, we conducted 21 experiments to investigate the SOA formation initiated by α-terpineol ozonolysis for high (0.84 h(-1) ), moderate (0.61 h(-1) ), and low (0.36 h(-1) ) air exchange rates (AER), which is the frequency with which indoor is replaced by outdoor air. α-Terpineol concentrations of 6.39 to 226 ppb were combined with high ozone (~25 ppm) to ensure rapid and complete ozonolysis. No reactants were replenished, so SOA peaked quickly and then decreased due to AER and surface losses, and peak SOA ranged from 2.03 to 281 μg/m(3) at unit density. SOA mass formation was parameterized with the aerosol mass fraction (AMF), a.k.a. the SOA yield, and AMFs ranged from 0.056 to 0.24. The AMFs strongly and positively correlated with reacted α-terpineol, whereas they weakly and negatively correlated with higher AERs. One-product, two-product, and volatility basis set (VBS) models were fit to the AMF data. Predictive modeling demonstrated that α-terpineol ozonolysis could meaningfully form SOA in indoor air.

  20. Profunda Femoris Pseudoaneurysm following Total Hip Arthroplasty Revision

    PubMed Central

    Harper, Katharine; Iorio, Justin; Balasubramanian, Easwaran

    2015-01-01

    Vascular injuries following total hip arthroplasty (THA) are very rare, with pseudoaneurysm being a small subset. We report a case of profunda femoris artery (PFA) pseudoaneurysm in a 61-year-old male following a posterior approach revision left THA. Presentation involved continued blood transfusion requirements several weeks postoperatively. Diagnosis of the pseduoaneurysm was made by contrast CT of the lower extremity, with confirmation via IR angiography. Successful embolization was achieved with selective coiling and Gelfoam. Presenting complaints of such complications are often vague and therefore lead to delayed diagnosis. Causes of such complications are not completely understood, particularly with PFA injuries in THA. Possible mechanisms are discussed in this paper. Vascular complications following THA can be difficult to diagnose. High suspicion in the setting of continued postoperative pain or bleeding may allow prompt diagnosis and avoidance of serious limb-threatening complications. PMID:26347839

  1. Expanding pseudoaneurysm compressing the coronary arteries and causing cardiogenic shock.

    PubMed

    Maliske, Seth M; Alshawabkeh, Laith; Schouweiler, Katie; Sigurdsson, Gardar

    2015-01-01

    A 37-year-old man who recently underwent aortic valve replacement after endocarditis presented with cardiogenic shock. A large expansile pseudoaneurysm was subsequently discovered using multiple imaging modalities. Although transesophageal echocardiography is important in diagnosing valve endocarditis, coronary CT angiography of prosthetic valves is feasible and image quality is good. In this case, coronary CT angiography allowed for better understanding of transesophageal echocardiography images and earlier diagnosis of coronary involvement as cause for left ventricular dysfunction.

  2. Pseudoaneurysm after heart transplantation with history of LVAD driveline infection.

    PubMed

    Omoto, T; Minami, K; Muramatsu, T; Kyo, S; Körfer, R

    2001-07-01

    An infective complication of the aorta is a potential cause of early and late mortality after heart transplantation. We report the case of a 21-year-old male cardiac transplant patient in whom a pseudoaneurysm of the recipient site of ascending aorta coincided with the site of the outflow prosthesis of a preexisting left ventricular assist device; this condition developed 9 months after transplantation.

  3. Secondary organic aerosols - formation and ageing studies in the SAPHIR chamber

    NASA Astrophysics Data System (ADS)

    Spindler, Christian; Müller, Lars; Trimborn, Achim; Mentel, Thomas; Hoffmann, Thorsten

    2010-05-01

    Secondary organic aerosol (SOA) formation from oxidation products of biogenic volatile organic compounds (BVOC) constitutes an important coupling between vegetation, atmospheric chemistry, and climate change. Such secondary organic aerosol components play an important role in particle formation in Boreal regions ((Laaksonen et al., 2008)), where biogenic secondary organic aerosols contribute to an overall negative radiative forcing, thus a negative feed back between vegetation and climate warming (Spracklen et al., 2008). Within the EUCAARI project we investigated SOA formation from mixtures of monoterpenes (and sesquiterpenes) as emitted typically from Boreal tree species in Southern Finland. The experiments were performed in the large photochemical reactor SAPHIR in Juelich at natural light and oxidant levels. Oxidation of the BVOC mixtures and SOA formation was induced by OH radicals and O3. The SOA was formed on the first day and then aged for another day. The resulting SOA was characterized by HR-ToF-AMS, APCI-MS, and filter samples with subsequent H-NMR, GC-MS and HPLC-MS analysis. The chemical evolution of the SOA is characterized by a fast increase of the O/C ratio during the formation process on the first day, stable O/C ratio during night, and a distinctive increase of O/C ratio at the second day. The increase of the O/C ratio on the second day is highly correlated to the OH dose and is accompanied by condensational growth of the particles. We will present simultaneous factor analysis of AMS times series (PMF, Ulbrich et al., 2009 ) and direct measurements of individual chemical species. We found that four factors were needed to represent the time evolution of the SOA composition (in the mass spectra) if oxidation by OH plays a mayor role. Corresponding to these factors we observed individual, representative molecules with very similar time behaviour. The correlation between tracers and AMS factors is astonishingly good as the molecular tracers

  4. Formation of secondary organic aerosol in the Paris pollution plume and its impact on surrounding regions

    NASA Astrophysics Data System (ADS)

    Zhang, Q. J.; Beekmann, M.; Freney, E.; Sellegri, K.; Pichon, J. M.; Schwarzenboeck, A.; Colomb, A.; Bourrianne, T.; Michoud, V.; Borbon, A.

    2015-12-01

    Secondary pollutants such as ozone, secondary inorganic aerosol, and secondary organic aerosol formed in the plumes of megacities can affect regional air quality. In the framework of the FP7/EU MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) project, an intensive campaign was launched in the greater Paris region in July 2009. The major objective was to quantify different sources of organic aerosol (OA) within a megacity and in its plume. In this study, we use airborne measurements aboard the French ATR-42 aircraft to evaluate the regional chemistry-transport model CHIMERE within and downwind of the Paris region. Two mechanisms of secondary OA (SOA) formation are used, both including SOA formation from oxidation and chemical aging of primary semivolatile and intermediate volatility organic compounds (SI-SOA) in the volatility basis set (VBS) framework. As for SOA formed from traditional VOC (volatile organic compound) precursors (traditional SOA), one applies chemical aging in the VBS framework adopting different SOA yields for high- and low-NOx environments, while another applies a single-step oxidation scheme without chemical aging. Two emission inventories are used for discussion of emission uncertainties. The slopes of the airborne OA levels versus Ox (i.e., O3 + NO2) show SOA formation normalized with respect to photochemical activity and are used for specific evaluation of the OA scheme in the model. The simulated slopes were overestimated slightly by factors of 1.1, 1.7 and 1.3 with respect to those observed for the three airborne measurements, when the most realistic "high-NOx" yields for traditional SOA formation in the VBS scheme are used in the model. In addition, these slopes are relatively stable from one day to another, which suggests that they are characteristic for the given megacity plume environment. The configuration with increased primary

  5. Formation of secondary minerals in a lysimeter approach - A mineral-microbe interaction

    NASA Astrophysics Data System (ADS)

    Schäffner, F.; Merten, D.; De Giudici, G.; Beyer, A.; Akob, D. M.; Ricci, P. C.; Küsel, K.; Büchel, G.

    2012-04-01

    Heavy metal contamination of large areas due to uranium mining operations poses a serious long-term environmental problem. In the Ronneburg district (eastern Thuringia, Germany), leaching of low grade uranium bearing ores (uranium content < 300 g/t) occurred from 1972 to 1990 using acid mine drainage (AMD; pH 2.7-2.8) and diluted sulphuric acid (10 g/l). Secondary mineral phases like birnessite, todorokite and goethite occur within a natural attenuation process associated with enrichment of heavy metals, especially Cd, Ni, Co, Cu and Zn due to a residual contamination even after remediation efforts. To reveal the processes of secondary mineral precipitation in the field a laboratory lysimeter approach was set up under in situ-like conditions. Homogenized soil from the field site and pure quartz sand were used as substrates. In general, in situ measurements of redox potentials in the substrates showed highly oxidizing conditions (200-750 mV). Water was supplied to the lysimeter from below via a mariottés bottle containing contaminated groundwater from the field. Evaporation processes were allowed, providing a continuous flow of water. This led to precipitation of epsomite and probably aplowite on the top layer of substrate, similar to what is observed in field investigations. After 4 weeks, the first iron and manganese bearing secondary minerals became visible. Soil water samples were used to monitor the behaviour of metals within the lysimeter. Saturation indices (SI) for different secondary minerals were calculated with PHREEQC. The SI of goethite showed oversaturation with respect to the soil solution. SEM-EDX analyses and IR spectroscopy confirmed the formation of goethite. Geochemical data revealed that goethite formation was mainly dominated by Eh/pH processes and that heavy metals, e.g. Zn and U, could be enriched in this phase. Although Eh/pH data does not support formation of manganese minerals, Mn(II)-oxidizing bacteria (MOB) could be isolated from field

  6. Secondary Organic Aerosol (SOA) formation from hydroxyl radical oxidation and ozonolysis of monoterpenes

    NASA Astrophysics Data System (ADS)

    Zhao, D. F.; Kaminski, M.; Schlag, P.; Fuchs, H.; Acir, I.-H.; Bohn, B.; Häseler, R.; Kiendler-Scharr, A.; Rohrer, F.; Tillmann, R.; Wang, M. J.; Wegener, R.; Wildt, J.; Wahner, A.; Mentel, T. F.

    2014-05-01

    Oxidation by hydroxyl radical (OH) and ozonolysis are the two major pathways of daytime biogenic volatile organic compounds (VOCs) oxidation and secondary organic aerosol (SOA) formation. In this study, we investigated the particle formation of several common monoterpenes (α-pinene, β-pinene, and limonene) by OH dominated oxidation, which has seldom been investigated. OH oxidation experiments were carried out in the SAPHIR chamber in Jülich, Germany, at low NOx (0.01-1 ppbV) and low ozone (O3) concentration. OH concentration and OH reactivity were measured directly so that the overall reaction rates of organic compounds with OH were quantified. Multi-generation reaction process, particle growth, new particle formation, particle yield, and chemical composition were analyzed and compared with that of monoterpene ozonolysis. Multi-generation products were found to be important in OH dominated SOA formation. The relative role of functionalization and fragmentation in the reaction process of OH oxidation was analyzed by examining the particle mass and the particle size as a function of OH dose. We developed a novel method which quantitatively links particle growth to the reaction of OH with organics in a reaction system. This method was also used to analyze the evolution of functionalization and fragmentation of organics in the particle formation by OH oxidation. It shows that functionalization of organics was dominant in the beginning of the reaction (within two lifetimes of the monoterpene) and fragmentation started to be dominant after that. We compared particle formation from OH oxidation with that from pure ozonolysis. In individual experiments, growth rates of the particle size did not necessarily correlate with the reaction rate of monoterpene with OH and O3. Comparing the size growth rates at the similar reaction rates of monoterpene with OH or O3 indicates that generally, OH oxidation and ozonolysis had similar efficiency in particle growth. The SOA yield of

  7. Secondary organic aerosol formation from hydroxyl radical oxidation and ozonolysis of monoterpenes

    NASA Astrophysics Data System (ADS)

    Zhao, D. F.; Kaminski, M.; Schlag, P.; Fuchs, H.; Acir, I.-H.; Bohn, B.; Häseler, R.; Kiendler-Scharr, A.; Rohrer, F.; Tillmann, R.; Wang, M. J.; Wegener, R.; Wildt, J.; Wahner, A.; Mentel, Th. F.

    2015-01-01

    Oxidation by hydroxyl radical (OH) and ozonolysis are the two major pathways of daytime biogenic volatile organic compound (BVOC) oxidation and secondary organic aerosol (SOA) formation. In this study, we investigated the particle formation of several common monoterpenes (α-pinene, β-pinene and limonene) by OH-dominated oxidation, which has seldom been investigated. OH oxidation experiments were carried out in the SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction) chamber in Jülich, Germany, at low NOx (0.01 ~ 1 ppbV) and low ozone (O3) concentration (< 20 ppbV). OH concentration and total OH reactivity (kOH) were measured directly, and through this the overall reaction rate of total organics with OH in each reaction system was quantified. Multi-generation reaction process, particle growth, new particle formation (NPF), particle yield and chemical composition were analyzed and compared with that of monoterpene ozonolysis. Multi-generation products were found to be important in OH-dominated SOA formation. The relative role of functionalization and fragmentation in the reaction process of OH oxidation was analyzed by examining the particle mass and the particle size as a function of OH dose. We developed a novel method which quantitatively links particle growth to the reaction rate of OH with total organics in a reaction system. This method was also used to analyze the evolution of functionalization and fragmentation of organics in the particle formation by OH oxidation. It shows that functionalization of organics was dominant in the beginning of the reaction (within two lifetimes of the monoterpene) and fragmentation started to play an important role after that. We compared particle formation from OH oxidation with that from pure ozonolysis. In individual experiments, growth rates of the particle size did not necessarily correlate with the reaction rate of monoterpene with OH and O3. Comparing the size growth rates at the similar reaction rates

  8. Intracranial Pseudoaneurysms, Fusiform Aneurysms and Carotid-Cavernous Fistulas

    PubMed Central

    Lv, Xianli; Jiang, Chuhan; Li, Youxiang; Lv, Ming; Zhang, Jingbo; Wu, Zhongxue

    2008-01-01

    Summary The study assessed the effectiveness and safety of endovascular covered stents in the management of intracranial pseudoaneurysms, fusiform aneurysms and direct carotid-cavernous fistulas. Fourteen endovascular covered stents were used to repair three pseudoaneurysms, six fu-siform aneurysms and six direct carotid-cavernous fistulas. Aneurysms were in the carotid artery in seven cases, in the vertebral artery two cases. It was not possible to treat two additional cases transcutaneously for technical reasons
2/15. Percutaneous closure of the lesions with an endovascular covered stent was successful in 13 of 15 cases. Initial follow-up showed good stent patency. No complications were observed after stent implantation. During follow-up, stent thromboses were detected in two of nine patients with follow-up digital subtracted angiography. One carotid-cavernous fistula of Barrow Type A transformed into Barrow Type D at nine month follow-up study was cured with a procudure of Onyx-18 injection. Endovascular covered stents may be an option for percutaneous closure of intracranial pseudoaneurysms, fusiform aneurysms and direct carotid-cavernous fistulas. Endoluminal vascular repair with covered stents offers an alternative therapeutic approach to conventional modalities. PMID:20557743

  9. Contribution of Glyoxal to Secondary Organic Aerosol Formation in Los Angeles

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Young, C. J.; Brown, S. S.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.

    2010-12-01

    Glyoxal (CHOCHO) is the simplest alpha-dicarbonyl and one of the most prevalent dicarbonyls in the atmosphere. It is an oxidation product of isoprene, and is also formed from the photooxidation of anthropogenic hydrocarbons, including aromatics and ethyne. In addition to its importance as a source of HOx, previous studies indicate that glyoxal reacts heterogeneously to form secondary organic aerosol. For the CalNex field campaign during summer 2010, we deployed a new glyoxal field instrument in Pasadena, California. This instrument consists of a broadband LED light source coupled to a cavity enhanced absorption spectrometer (IBBCEAS). The effective pathlength of the instrument is approximately 18 km. The measurement precision of the glyoxal instrument allows us to observe diurnal variability and trends. The glyoxal measurements were co-located with a comprehensive set of hydrocarbon measurements. These included the important photochemical precursors for CHOCHO, with measurements of isoprene, ethyne, ethene, monoterpenes, aromatics, and methylbutenol. We use the precursor concentrations to evaluate expected glyoxal concentrations. The difference between the expected gas-phase production of glyoxal and the measured concentrations indicates the contribution that glyoxal makes to secondary organic aerosol formation in Los Angeles.

  10. The role of dicentric chromosome formation and secondary centromere deletion in the evolution of myeloid malignancy.

    PubMed

    Mackinnon, Ruth N; Campbell, Lynda J

    2011-01-01

    Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes, together with other unrecognized dicentric chromosomes, points to a greater role for dicentric chromosomes in cancer initiation and progression than is generally acknowledged. We present a model that predicts and explains a significant role for dicentric chromosomes in the formation of unbalanced translocations in malignancy.

  11. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees.

    PubMed

    Liu, Lijun; Filkov, Vladimir; Groover, Andrew

    2014-06-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary growth), but a comprehensive understanding of how these genes interact to influence woody growth is currently lacking. Modeling transcriptional networks has recently been made tractable by next-generation sequencing-based technologies that can comprehensively catalog gene expression and transcription factor-binding genome-wide, but has not yet been extensively applied to undomesticated tree species or woody growth. Here we discuss basic features of transcriptional networks, approaches for modeling biological networks, and examples of biological network models developed for forest trees to date. We discuss how transcriptional network research is being developed in the model forest tree genus, Populus, and how this research area can be further developed and applied. Transcriptional network models for forest tree secondary growth and wood formation could ultimately provide new predictive models to accelerate hypothesis-driven research and develop new breeding applications.

  12. Formation and aging of secondary organic aerosol from toluene: changes in chemical composition, volatility, and hygroscopicity

    DOE PAGES

    Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.; ...

    2015-07-24

    Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NOx under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OSc), and mass yield. The OA oxidation state generally increased duringmore » photo-oxidation, and the final OA OSc ranged from -0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. There was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

  13. RGM regulates BMP-mediated secondary axis formation in the sea anemone Nematostella vectensis.

    PubMed

    Leclère, Lucas; Rentzsch, Fabian

    2014-12-11

    Patterning of the metazoan dorsoventral axis is mediated by a complex interplay of BMP signaling regulators. Repulsive guidance molecule (RGM) is a conserved BMP coreceptor that has not been implicated in axis specification. We show that NvRGM is a key positive regulator of BMP signaling during secondary axis establishment in the cnidarian Nematostella vectensis. NvRGM regulates first the generation and later the shape of a BMP-dependent Smad1/5/8 gradient with peak activity on the side opposite the NvBMP/NvRGM/NvChordin expression domain. Full knockdown of Smad1/5/8 signaling blocks the formation of endodermal structures, the mesenteries, and the establishment of bilateral symmetry, while altering the gradient through partial NvRGM or NvBMP knockdown shifts the boundaries of asymmetric gene expression and the positioning of the mesenteries along the secondary axis. These findings provide insight into the diversification of axis specification mechanisms and identify a previously unrecognized role for RGM in BMP-mediated axial patterning.

  14. Formation of secondary carbonates and native sulphur in sulphate-rich Messinian strata, Sicily

    NASA Astrophysics Data System (ADS)

    Ziegenbalg, S. B.; Brunner, B.; Rouchy, J. M.; Birgel, D.; Pierre, C.; Böttcher, M. E.; Caruso, A.; Immenhauser, A.; Peckmann, J.

    2010-05-01

    Microbially formed authigenic carbonates accompanied by native sulphur are present in the 'Calcare Solfifero' below a thick succession of gypsum deposited during the Messinian salinity crisis in Sicily. We sampled these carbonates and associated sulphur in five former sulphur mines to subject them to a detailed petrographic and geochemical study in order to explore their different modes of formation. Native sulphur formed in conjunction with microbial sulphate reduction, which is reflected in its depletion in 34S ( δ34S values as low as - 2‰ vs. V-CDT) and an enrichment of 34S in the residual sulphate ( δ34S values as high as + 61‰). The oxidation of organic matter by sulphate reduction increased alkalinity, inducing precipitation of secondary carbonate minerals. A set of authigenic limestones lacking sulphate minerals, but characterized by pseudomorphs after gypsum and high δ18O values (as high as + 9‰ vs. V-PDB) reflects syngenetic mineral formation within evaporitic settings. Low δ13C values (as low as - 52‰ vs. V-PDB) reveal that these carbonate phases were formed by microbial sulphate reduction coupled to the oxidation of biogenic methane. Another set of authigenic carbonates that replaced sulphate minerals is typified by low δ18O values (as low as - 4‰). These carbonates formed epigenetically during later diagenesis following compaction. Dissolution of gypsum or anhydrite by meteoric waters delivered the sulphate for microbial sulphate reduction. Low carbon isotope values of these carbonates (- 29 to - 5‰) indicate that carbonate was derived from the oxidation of crude oil and possibly minor methane, partly involving different degrees of admixture of dissolved carbonate from other sources. Although the studied rocks with their vast amounts of secondary carbonate minerals and sulphur seem to indicate a similar genesis at first glance - having formed by biogeochemical transformations of sulphate and hydrocarbons - this study reveals that these

  15. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-02-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  16. Formation of hydroxyl radicals from photolysis of secondary organic aerosol material

    NASA Astrophysics Data System (ADS)

    Badali, K. M.; Zhou, S.; Aljawhary, D.; Antiñolo, M.; Chen, W. J.; Lok, A.; Mungall, E.; Wong, J. P. S.; Zhao, R.; Abbatt, J. P. D.

    2015-02-01

    This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA aerosol is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both α-pinene and limonene SOA, are measured from the formation rate of p-hydroxybenzoic acid as measured using offline HPLC analysis. To evaluate whether the OH is formed by photolysis of H2O2 or organic hydroperoxides (ROOH), the peroxide content of the SOA was measured using the horseradish peroxidase-dichlorofluorescein (HRP-DCF) assay, which was calibrated using H2O2. The OH formation rates from SOA are five times faster than from the photolysis of H2O2 solutions whose concentrations correspond to the peroxide content of the SOA solutions assuming that the HRP-DCF signal arises from H2O2 alone. The higher rates of OH formation from SOA are likely due to ROOH photolysis. This result is substantiated by photolysis experiments conducted with t-butyl hydroperoxide and cumene hydroperoxide which produce over three times more OH than photolysis of equivalent concentrations of H2O2. Relative to the peroxide level in the SOA, the quantum yield for OH generation from α-pinene SOA is 0.8 ± 0.4. This is the first demonstration of an efficient photolytic source of OH in SOA, one that may affect both cloudwater and aerosol chemistry.

  17. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-06-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  18. Formation and aging of secondary organic aerosol from isoprene photooxidation during cloud condensation-evaporation cycles

    NASA Astrophysics Data System (ADS)

    Giorio, C.; Siekmann, F.; Bregonzio, L.; Temime-Roussel, B.; Ravier, S.; Tapparo, A.; Kalberer, M.; Doussin, J.; Monod, A.

    2013-12-01

    Biogenic volatile organic compounds (BVOCs) can be oxidized in the gas phase to form more water-soluble compounds which could partition into atmospheric water droplets. Oxidation processes in the liquid phase could produce high molecular weight and less volatile compounds which can partly remain in the particle phase after water evaporation (Ervens et al., 2011). This work investigates the formation and composition of secondary organic aerosol (SOA) from the photooxidation of isoprene (the most abundant BVOC) and methacrolein (its main first-generation oxidation product). The experiments were performed during the CUMULUS (CloUd MULtiphase chemistry of organic compoUndS in the troposphere) campaigns at the 4.2 m3 stainless steel CESAM chamber at LISA, specifically designed to investigate multiphase processes (Wang et al., 2011). In each experiment, 500/1000 ppb of isoprene or methacrolein were injected in the chamber together with HONO before irradiation. Gas phase oxidation products have been analyzed on-line by a Proton Transfer Reaction Mass Spectrometer (PTR-MS) and a Fourier Transform Infrared Spectrometer (FTIR) together with NOx and O3 analyzers. SOA formation and composition has been followed on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-Of-Flight Aerosol Mass Spectrometer (HR-TOF-AMS). Particular attention has been focused on the study of SOA formation and aging during cloud condensation-evaporation cycles simulated in the smog chamber. In all experiments, we noted that water soluble gas-phase oxidation products readily partition into cloud droplets accompanied by a prompt SOA production during cloud formation which partly persists after cloud evaporation. Ervens, B. et al. (2011) Atmos. Chem. Phys. 11, 11069 11102. Wang, J. et al. (2011) Atmos. Measur. Tech. 4, 2465 2494.

  19. Digital artery pseudoaneurysm in a patient with previous radial artery harvest

    PubMed Central

    Plant, Mathew A; Panchapakesan, Vivek

    2011-01-01

    A post-traumatic pseudoaneurysm in the ulnar digital artery of the thumb in a patient with compromised vascularity due to a previous harvest of the ipsilateral radial artery is reported. To the authors’ knowledge, the present case is the first such description of a pseudoaneurysm in the digital artery of a patient with compromised collateral blood flow. PMID:23204888

  20. Endovascular Stent-Graft Placement as Emergency Treatment for Ruptured Iliac Pseudoaneurysm

    SciTech Connect

    Aytekin, Cueneyt; Boyvat, Fatih; Yildirim, Erkan; Coskun, Mehmet

    2002-08-15

    A 65-year-old woman with advanced mucinous carcinoma of the ovary presented with massive rectal bleeding caused by rupture of an iliac artery pseudoaneurysm into the bowel. Surgery was contraindicated due to the patient's poor clinical condition. We successfully placed an endovascular stent-graft that excluded the pseudoaneurysm. There were no complications, and the patient recovered well.

  1. Left ventricular pseudoaneurysm found after mitral valve replacement performed 30 years earlier.

    PubMed

    Castilla, Elena; Gato, Manuel; Ruiz, José Ramón

    2010-03-01

    Pseudoaneurysm of the left ventricle (LV) is a rare cardiac disease that occurs after myocardial infarction or cardiac surgery. Because patients frequently present with nonspecific symptoms, a high index of suspicion is needed to make the diagnosis. This report describes an unusual case demonstrating a large LV pseudoaneurysm after mitral valve replacement performed 30 years earlier.

  2. Superselective embolization of superior gluteal artery pseudoaneurysms following intramuscular injection: case report.

    PubMed

    Vauthey, J N; Maddern, G J; Balsiger, D; Blumgart, L H; Triller, J

    1991-08-01

    Two bleeding superior gluteal artery pseudoaneurysms occurred in a patient with advanced malignant disease following an intramuscular injection. This was diagnosed by angiography and successfully managed by superselective embolization. This avoided further surgery and no additional complication from the pseudoaneurysm occurred up to the time of the patient's demise.

  3. Percutaneous Endovascular Stent-Graft for Iliac Pseudoaneurysm Following Lumbar Discectomy

    SciTech Connect

    Hong, Seong J.; Oh, Joo H.; Yoon, Yup

    2000-11-15

    In a 24-year-old woman, an iliac pseudoaneurysm following lumbar discectomy was successfully treated by percutaneous placement of a self-expanding stent-graft. A postprocedural angiogram demonstrated complete exclusion of the pseudoaneurysm without leakage of contrast agent.

  4. Formation of secondary aerosols from biomass burning plumes: chamber simulation study

    NASA Astrophysics Data System (ADS)

    Wang, X.; Hu, Q.; Fang, Z.; Deng, W.

    2015-12-01

    Biomass burning contributed substantially to carbonaceous aerosols in China's ambient air, even in its highly industrialized megacities, based on recent source attributions by receptor modeling or by molecular and isotopic tracers. Although chemical evolution of biomass burning plumes in the ambient is a vital issue for the study of climatic and health effects, the understanding of secondary pollutants formation during the aging of biomass burning plumes is far from complete. Here we collected typical agriculture residues and forest plant branches in the Pearl River Delta in south China, and got them burned in laboratory-controlled conditions and introduced the plumes from burning these biomass directly into the GIGCAS indoor smog chamber with a reactor of 30 m3 to investigate the photochemical aging of the plumes. The inorganic trace gases, including SO2, NOx, NH3 and O3, were monitored online with chemiluminescence gas analyzers, precursor volatile organic compounds (VOCs) were monitor online with a PTR-ToF-MS and offline by a preconcentrator coupled with a gas chromatography-mass selective detector/flame ionization detector/electron capture detector (GC-MSD/FID/ECD), particle number concentrations and size distributions were obtained using a scanning mobility particle sizer (SMPS), and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) was used to measure the chemical compositions and evolutions of submicron aerosols and to trace the change in the average element ratios of organics, like H/C, O/C, and N/C. The results from the study were summarized in the following aspects: 1) primary emission factors of gaseous and particulate pollutants from burning of typical biomass including agricultural remains and forest wood plants; 2) yields of secondary pollutants, including secondary inorganic and organic aerosols and gaseous products (like O3) during photochemical aging of biomass burning plumes; 3) relationship between the formed secondary

  5. Secondary Organic Aerosol Formation by Molecular-Weight Building Reactions of Biogenic Oxidation Products

    NASA Astrophysics Data System (ADS)

    Barsanti, K.; Guenther, A.; Matsunaga, S.; Smith, J.

    2006-12-01

    Understanding the chemical composition of atmospheric organic aerosols (OA) remains one of the significant challenges to accurately representing OA in air quality and climate models. Meeting this challenge will require further understanding of secondary organic aerosols (SOA), of which biogenic emissions are thought to be major precursors. Of recent interest is the significance of higher-molecular weight (MW) compounds (i.e., "oligomers"). Theoretical, laboratory, and field study results suggest that relatively volatile oxidation products may contribute to SOA formation through multi-phase MW- building reactions. The significance of such reactions for biogenic SOA formation, including for newly considered precursors such as isoprene, is explored in this work. Theoretical and field studies are employed to: 1) identify MW-building reactions that may contribute to SOA formation in the atmosphere, 2) identify MW-building reaction products in ambient samples, and 3) parameterize atmospheric SOA formation by MW-building reactions of biogenic oxidation products. Likely reactions of biogenic oxidation products include ester, amide, and peroxyhemiacetal formation. Each of the proposed reactions involves known oxidation productions of biogenic precursors (e.g., carboxylic acids and aldehydes) reacting with one another and/or other atmospheric constituents (e.g., sulfuric acid and ammonia) to form higher-MW/lower-volatility products that can condense to form SOA. It has been suggested that products of MW-building reactions can revert to the parent reactants during sampling and analysis. Thus, relatively volatile compounds detected in ambient particle samples in fact may be decomposition products of higher-MW products. The contribution of relatively volatile biogenic oxidation products to SOA via ester, amide, and peroxyhemiacetal formation, as determined by studies based on fundamental thermodynamics and gas/particle partitioning theory, will be discussed; in addition to

  6. Telescoping Dual Covered Stent Graft Construct for Endovascular Treatment of a Giant Extracranial Carotid Artery Pseudoaneurysm

    PubMed Central

    Ding, Dale; Starke, Robert M.; Moriarty, Maurice; Brew, Stefan

    2016-01-01

    Large pseudoaneurysms which compress the parent vessel are challenging lesions to successfully treat with endovascular therapy. We describe the endovascular treatment of a giant extracranial carotid artery (ECCA) pseudoaneurysm resulting in substantial mass effect on the common carotid artery (CCA) bifurcation using a telescoping dual covered stent graft construct. A 56-year-old male was diagnosed with an 8.5 cm × 13 cm pseudoaneurysm arising from the left CCA bifurcation, which was causing luminal narrowing of the CCA and proximal internal carotid artery (ICA). The patient underwent endovascular intervention, during which a balloon-expandable covered stent was deployed within a heparin-bonded covered stent, such that the overall construct spanned from the CCA to the lower cervical ICA. The employment of a telescoping dual covered stent technique can successfully treat appropriately selected patients with large or giant ECCA pseudoaneurysms, with the concomitant goals of excluding the pseudoaneurysm and restoring the luminal caliber of the parent artery. PMID:28163519

  7. Telescoping Dual Covered Stent Graft Construct for Endovascular Treatment of a Giant Extracranial Carotid Artery Pseudoaneurysm.

    PubMed

    Ding, Dale; Starke, Robert M; Moriarty, Maurice; Brew, Stefan

    2016-12-01

    Large pseudoaneurysms which compress the parent vessel are challenging lesions to successfully treat with endovascular therapy. We describe the endovascular treatment of a giant extracranial carotid artery (ECCA) pseudoaneurysm resulting in substantial mass effect on the common carotid artery (CCA) bifurcation using a telescoping dual covered stent graft construct. A 56-year-old male was diagnosed with an 8.5 cm × 13 cm pseudoaneurysm arising from the left CCA bifurcation, which was causing luminal narrowing of the CCA and proximal internal carotid artery (ICA). The patient underwent endovascular intervention, during which a balloon-expandable covered stent was deployed within a heparin-bonded covered stent, such that the overall construct spanned from the CCA to the lower cervical ICA. The employment of a telescoping dual covered stent technique can successfully treat appropriately selected patients with large or giant ECCA pseudoaneurysms, with the concomitant goals of excluding the pseudoaneurysm and restoring the luminal caliber of the parent artery.

  8. Ethylene glycol emissions from on-road vehicles: implications for aqueous phase secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Wood, E. C.; Knighton, W. B.; Fortner, E.; Herndon, S. C.; Onasch, T. B.; Franklin, J.; Harley, R. A.; Gentner, D. R.; Goldstein, A. H.

    2012-12-01

    Ethylene glycol (HOCH2CH2OH), used as an engine coolant for most on-road vehicles, is an intermediate volatility organic compound (IVOC) with a high Henry's Law Coefficient (kH > 10,000 M atm-1) . Oxidation of ethylene glycol, especially in the atmospheric aqueous phase (clouds, fog, wet aerosol), can lead to the formation of glycolaldehyde, oxalic acid, and ultimately secondary organic aerosol. We present measurements of unexpectedly high ethylene glycol emissions in the Caldecott Tunnel near San Francisco (Summer 2010) and the Washburn Tunnel near Houston (Spring 2009). Ethylene glycol was detected using a proton-transfer reaction mass spectrometer (PTR-MS) at m/z = 45, which is usually interpreted as acetaldehyde. Although not necessarily a tailpipe emission, effective fuel-based emission factors are calculated using the carbon balance method and range from 50 to 400 mg ethylene glycol per kg fuel. Total US and global emissions are estimated using these emission factors and fuel consumption rates and are compared to previous model estimates of ethylene glycol emissions (e.g., the Regional Atmospheric Chemistry Model). Compared to biogenically emitted isoprene, ethylene glycol is likely a minor source of glycolaldehyde globally, but may contribute significantly to glycolaldehyde, oxalate and SOA formation in areas dominated by urban emissions.

  9. Constraining condensed-phase formation kinetics of secondary organic aerosol components from isoprene epoxydiols

    NASA Astrophysics Data System (ADS)

    Riedel, T. P.; Lin, Y.-H.; Zhang, Z.; Chu, K.; Thornton, J. A.; Vizuete, W.; Gold, A.; Surratt, J. D.

    2016-02-01

    Isomeric epoxydiols from isoprene photooxidation (IEPOX) have been shown to produce substantial amounts of secondary organic aerosol (SOA) mass and are therefore considered a major isoprene-derived SOA precursor. Heterogeneous reactions of IEPOX on atmospheric aerosols form various aerosol-phase components or "tracers" that contribute to the SOA mass burden. A limited number of the reaction rate constants for these acid-catalyzed aqueous-phase tracer formation reactions have been constrained through bulk laboratory measurements. We have designed a chemical box model with multiple experimental constraints to explicitly simulate gas- and aqueous-phase reactions during chamber experiments of SOA growth from IEPOX uptake onto acidic sulfate aerosol. The model is constrained by measurements of the IEPOX reactive uptake coefficient, IEPOX and aerosol chamber wall losses, chamber-measured aerosol mass and surface area concentrations, aerosol thermodynamic model calculations, and offline filter-based measurements of SOA tracers. By requiring the model output to match the SOA growth and offline filter measurements collected during the chamber experiments, we derive estimates of the tracer formation reaction rate constants that have not yet been measured or estimated for bulk solutions.

  10. Interpretation of Secondary Organic Aerosol Formation from Diesel Exhaust Photooxidation in an Environmental Chamber

    SciTech Connect

    Nakao, Shunsuke; Shrivastava, ManishKumar B.; Nguyen, Anh; Jung, Hee-Jung; Cocker, David R.

    2011-04-14

    Secondary organic aerosol (SOA) formation from diesel exhaust in a smog chamber was investigated. Particle volume measurement based on mobility diameter is shown to underestimate SOA formation from diesel exhaust due to the external void space of agglomerate particles, in which case mass-based measurement technique is necessary. Rapid determination of particle effective density as a function of particle mass was performed by an Aerosol Particle Mass analyzer – Scanning Mobility Particle Sizer (APM-SMPS) to obtain particle mass concentration and fractal dimension. Continuous aging of aerosol was observed in terms of atomic ratio (O/C), from 0.05 to 0.25 in 12 hours, underscoring the importance of multi-generational oxidation of low-volatile organic vapors emitted from diesel engine as the significant source of oxygenated SOA. Experimental conditions possibly have strong impacts on physical evolution of diesel particulates in a smog chamber. Higher particle effective densities were observed when raw exhaust was injected into a full bag as opposed to filling a bag with diluted exhaust using an ejector diluter. When longer transfer line was used for injecting diesel exhaust into the smog chamber, rapid particle coagulation was observed, leading to increasing particle volume concentration in dark while its mass concentration is decreasing.

  11. Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions.

    PubMed

    Gentner, Drew R; Jathar, Shantanu H; Gordon, Timothy D; Bahreini, Roya; Day, Douglas A; El Haddad, Imad; Hayes, Patrick L; Pieber, Simone M; Platt, Stephen M; de Gouw, Joost; Goldstein, Allen H; Harley, Robert A; Jimenez, Jose L; Prévôt, André S H; Robinson, Allen L

    2017-02-07

    Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.

  12. Role of Aerosol Liquid Water in Secondary Organic Aerosol Formation from Volatile Organic Compounds.

    PubMed

    Faust, Jennifer A; Wong, Jenny P S; Lee, Alex K Y; Abbatt, Jonathan P D

    2017-02-07

    A key mechanism for atmospheric secondary organic aerosol (SOA) formation occurs when oxidation products of volatile organic compounds condense onto pre-existing particles. Here, we examine effects of aerosol liquid water (ALW) on relative SOA yield and composition from α-pinene ozonolysis and the photooxidation of toluene and acetylene by OH. Reactions were conducted in a room-temperature flow tube under low-NOx conditions in the presence of equivalent loadings of deliquesced (∼20 μg m(-3) ALW) or effloresced (∼0.2 μg m(-3) ALW) ammonium sulfate seeds at exactly the same relative humidity (RH = 70%) and state of wall conditioning. We found 13% and 19% enhancements in relative SOA yield for the α-pinene and toluene systems, respectively, when seeds were deliquesced rather than effloresced. The relative yield doubled in the acetylene system, and this enhancement was partially reversible upon drying the prepared SOA, which reduced the yield by 40% within a time scale of seconds. We attribute the high relative yield of acetylene SOA on deliquesced seeds to aqueous partitioning and particle-phase reactions of the photooxidation product glyoxal. The observed range of relative yields for α-pinene, toluene, and acetylene SOA on deliquesced and effloresced seeds suggests that ALW plays a complicated, system-dependent role in SOA formation.

  13. Primary particulate emissions and secondary organic aerosol (SOA) formation from idling diesel vehicle exhaust in China.

    PubMed

    Deng, Wei; Hu, Qihou; Liu, Tengyu; Wang, Xinming; Zhang, Yanli; Song, Wei; Sun, Yele; Bi, Xinhui; Yu, Jianzhen; Yang, Weiqiang; Huang, Xinyu; Zhang, Zhou; Huang, Zhonghui; He, Quanfu; Mellouki, Abdelwahid; George, Christian

    2017-03-26

    In China diesel vehicles dominate the primary emission of particulate matters from on-road vehicles, and they might also contribute substantially to the formation of secondary organic aerosols (SOA). In this study tailpipe exhaust of three typical in-use diesel vehicles under warm idling conditions was introduced directly into an indoor smog chamber with a 30m(3) Teflon reactor to characterize primary emissions and SOA formation during photo-oxidation. The emission factors of primary organic aerosol (POA) and black carbon (BC) for the three types of Chinese diesel vehicles ranged 0.18-0.91 and 0.15-0.51gkg-fuel(-1), respectively; and the SOA production factors ranged 0.50-1.8gkg-fuel(-1) and SOA/POA ratios ranged 0.7-3.7 with an average of 2.2. The fuel-based POA emission factors and SOA production factors from this study for idling diesel vehicle exhaust were 1-3 orders of magnitude higher than those reported in previous studies for idling gasoline vehicle exhaust. The emission factors for total particle numbers were 0.65-4.0×10(15)particleskg-fuel(-1), and particles with diameters less than 50nm dominated in total particle numbers. Traditional C2-C12 precursor non-methane hydrocarbons (NMHCs) could only explain less than 3% of the SOA formed during aging and contribution from other precursors including intermediate volatile organic compounds (IVOC) needs further investigation.

  14. Efficient Isoprene Secondary Organic Aerosol Formation from a Non-IEPOX Pathway

    SciTech Connect

    Liu, Jiumeng; D’Ambro, Emma L.; Lee, Ben H.; Lopez-Hilfiker, Felipe D.; Zaveri, Rahul A.; Rivera-Rios, Jean C.; Keutsch, Frank N.; Iyer, Siddharth; Kurten, Theo; Zhang, Zhenfa; Gold, Avram; Surratt, Jason D.; Shilling, John E.; Thornton, Joel A.

    2016-09-20

    With a large global emission rate and high reactivity, isoprene has a profound effect upon atmospheric chemistry and composition. The atmospheric pathways by which isoprene converts to secondary organic aerosol (SOA) and how anthropogenic pollutants such as nitrogen oxides and sulfur affect this process are a subject of intense research because particles affect Earth’s climate and local air quality. In the absence of both nitrogen oxides and reactive aqueous seed particles, we measure SOA mass yields from isoprene photochemical oxidation of up to 15%, which are factors of 2, or more, higher than those typically used in coupled chemistry-climate models. SOA yield is initially constant with the addition of increasing amounts of nitric oxide (NO) but then sharply decreases for input concentrations above 10 ppbv. Online measurements of aerosol molecular composition show that the fate of second-generation RO2 radicals is key to understanding the efficient SOA formation and the NOx dependent yields described here and in the literature. These insights allow for improved quantitative estimates of SOA formation in the pre-industrial atmosphere and in biogenic-rich regions with limited anthropogenic impacts and suggest a more complex representation of NOx dependent SOA yields may be important in models.

  15. Effects of meteorology and secondary particle formation on visibility during heavy haze events in Beijing, China.

    PubMed

    Zhang, Qiang; Quan, Jiannong; Tie, Xuexi; Li, Xia; Liu, Quan; Gao, Yang; Zhao, Delong

    2015-01-01

    The causes of haze formation in Beijing, China were analyzed based on a comprehensive measurement, including PBL (planetary boundary layer), aerosol composition and concentrations, and several important meteorological parameters such as visibility, RH (relative humidity), and wind speed/direction. The measurement was conducted in an urban location from Nov. 16, 2012 to Jan. 15, 2013. During the period, the visibility varied from >20 km to less than a kilometer, with a minimum visibility of 667 m, causing 16 haze occurrences. During the haze occurrences, the wind speeds were less than 1m/s, and the concentrations of PM2.5 (particle matter with radius less than 2.5 μm) were often exceeded 200 μg/m(3). The correlation between PM2.5 concentration and visibility under different RH values shows that visibility was exponentially decreased with the increase of PM2.5 concentrations when RH was less than 80%. However, when RH was higher than 80%, the relationship was no longer to follow the exponentially decreasing trend, and the visibility maintained in very low values, even with low PM2.5 concentrations. Under this condition, the hygroscopic growth of particles played important roles, and a large amount of water vapor acted as particle matter (PM) for the reduction of visibility. The variations of meteorological parameters (RH, PBL heights, and WS (wind speed)), chemical species in gas-phase (CO, O3, SO2, and NOx), and gas-phase to particle-phase conversions under different visibility ranges were analyzed. The results show that from high visibility (>20 km) to low visibility (<2 km), the averaged PBL decreased from 1.24 km to 0.53 km; wind speeds reduced from 1m/s to 0.5m/s; and CO increased from 0.5 ppmv to 4.0 ppmv, suggesting that weaker transport/diffusion caused the haze occurrences. This study also found that the formation of SPM (secondary particle matter) was accelerated in the haze events. The conversions between SO2 and SO4 as well as NOx to NO3(-) increased

  16. Secondary Organic Aerosol formation from isoprene photooxidation under dry conditions (CUMULUS project)

    NASA Astrophysics Data System (ADS)

    Brégonzio-Rozier, Lola; Siekmann, Frank; Giorio, Chiara; Temime-Roussel, Brice; Pangui, Edouard; Morales, Sébastien; Gratien, Aline; Ravier, Sylvain; Monod, Anne; Doussin, Jean-Francois

    2014-05-01

    Isoprene (2-methyl-1,3-butadiene, C5H8) is one of the most abundant non-methane hydrocarbons emitted into the troposphere. Its annual global emission has recently been estimated in the range of 440 to 660 TgC (Guenther et al., 2006). Because of its large concentrations and high reactivity with the hydroxyl radical (OH), isoprene can have a strong influence on tropospheric photochemistry. It has been determined recently that isoprene also plays a role in secondary organic aerosol (SOA) formation in the ambient atmosphere even if isoprene leads to low SOA yields. The aim of the present work was to study isoprene photo-oxidation with OH radical in order to investigate its oxidation products and resulting aerosol production. A special care was taken to the realism of the experiment: light source, NOx and OH levels and aging time (around 10 hours). Experiments were performed in the CESAM chamber (Wang et al., 2011) which was designed to investigate multiphase processes under realistic actinic flux, and accurate control of temperature. In each experiment, around 800 ppb of isoprene was injected in the chamber together with the OH source under dry conditions (<5 %RH) before irradiation. Gas-phase composition was analyzed in-situ by a Fourier Transform Infrared Spectrometer (FTIR), a Proton Transfer Reaction Mass Spectrometer (PTR-TOF-MS) and NOx and ozone analyzers. A Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-Of-Flight Aerosol Mass Spectrometer (HR-TOF-AMS) were also used to investigate SOA formation and composition. In all experiments, we noted a SOA production at the end of isoprene oxidation i.e. exhibiting a clear secondary products type growth. Several results (including SOA densities and yields, and O/C ratios) were obtained using SMPS and AMS data allowing us to characterize SOA formation and composition during the experiments. The characterization of the gaseous and particulate phases will be presented. While the SOA yields in

  17. Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car

    NASA Astrophysics Data System (ADS)

    Karjalainen, Panu; Timonen, Hilkka; Saukko, Erkka; Kuuluvainen, Heino; Saarikoski, Sanna; Aakko-Saksa, Päivi; Murtonen, Timo; Bloss, Matthew; Dal Maso, Miikka; Simonen, Pauli; Ahlberg, Erik; Svenningsson, Birgitta; Brune, William Henry; Hillamo, Risto; Keskinen, Jorma; Rönkkö, Topi

    2016-07-01

    Changes in vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic-related emissions, both primary (direct) particulate emission and secondary particle formation (from gaseous precursors in the exhaust emissions) need to be characterized. In this study, we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a Euro 5 level gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the tailpipe to the atmosphere, and also takes into account differences in driving patterns. We observed that, in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence.

  18. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    NASA Technical Reports Server (NTRS)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  19. Field Observation of Heterogeneous Formation of Secondary Organic Aerosols on Asian Mineral Dust Surfaces

    NASA Astrophysics Data System (ADS)

    Wang, G.

    2014-12-01

    This study investigated the heterogeneous formation mechanism of secondary organic aerosols (SOA) on dust surfaces by characterizing molecular compositions and size distributions of dicarboxylic acids, keto-carboxylic acids, a-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) in the urban atmosphere of Xi'an, China during dust storm periods and comparing with those in non-dust storm periods. In the presence of a dust storm, all the above mentioned SOA species in Xi'an are predominantly enriched on coarse particles (>2.1 µm). Oxalic acid well correlated with NO3- (r2=0.72, p<0.01) rather than SO42-. This phenomenon differs greatly from the observed particles during a non-dust storm period, which is characterized by an enrichment of the SOA on fine particles (<2.1 µm) with a strong correlation between C2 and SO42-. We propose a three-step formation pathway to explain these observations as follows. First, nitric acid and nitrogen oxides react with dust to form a liquid film on the surface via water vapor-absorption of calcium nitrate. Second, gaseous Gly and mGly partition into the aqueous-phase. Finally, the aqueous-phase Gly and mGly oxidize into glyoxylic acid (wC2), followed by a further oxidation into C2. To the best of our knowledge, we found for the first time the enrichments of glyoxal (Gly) and methylglyoxal (mGly) on dust surfaces. Our data indicate a more critical role of nitrate than sulfate in the heterogeneous formation process of SOA on dust surfaces. Mass ratio of C2 to wC2 was found to be higher in coarse particles than in fine particles during the dust storm events, which is due to low acidity condition of large particles that is favorable for conversion of wC2 to C2.

  20. Secondary organic aerosol formation from idling gasoline passenger vehicle emissions investigated in a smog chamber

    NASA Astrophysics Data System (ADS)

    Nordin, E. Z.; Eriksson, A. C.; Roldin, P.; Nilsson, P. T.; Carlsson, J. E.; Kajos, M. K.; Hellén, H.; Wittbom, C.; Rissler, J.; Löndahl, J.; Swietlicki, E.; Svenningsson, B.; Bohgard, M.; Kulmala, M.; Hallquist, M.; Pagels, J. H.

    2013-06-01

    Gasoline vehicles have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from three passenger vehicles (EURO2-EURO4) were investigated with photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out down to atmospherically relevant organic aerosol mass concentrations. The characterization instruments included a high-resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind of urban areas. After a cumulative OH exposure of ~5 × 106 cm-3 h, the formed SOA was 1-2 orders of magnitude higher than the primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 43), approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6-C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher-order aromatic compounds such as C10 and C11 light aromatics, naphthalene and methyl-naphthalenes. We conclude that approaches using only light aromatic precursors give an incomplete picture of the magnitude of SOA formation and the SOA composition from gasoline exhaust.

  1. Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Liggio, J.; Staebler, R.; Li, S.-M.

    2015-06-01

    As a class of brown carbon, organonitrogen compounds originating from the heterogeneous uptake of NH3 by secondary organic aerosol (SOA) have received significant attention recently. In the current work, particulate organonitrogen formation during the ozonolysis of α-pinene and the OH oxidation of m-xylene in the presence of ammonia (34-125 ppb) is studied in a smog chamber equipped with a High Resolution Time-of-Flight Aerosol Mass Spectrometer and a Quantum Cascade Laser instrument. A large diversity of nitrogen containing organic (NOC) fragments was observed which were consistent with the reaction of ammonia with carbonyl containing SOA. The uptake coefficients of NH3 to SOA leading to organonitrogen compounds are reported for the first time and were in the range of ∼ 10-3-10-2, decreasing significantly to < 10-5 after 6 h of reaction. At the end of experiments (∼ 6 h) the NOC mass contributed 8.9 ± 1.7 and 31.5 ± 4.4 wt% to the total α-pinene and m-xylene derived SOA, and 4-15 wt% of the total nitrogen in the system. Uptake coefficients were also found to be positively correlated with particle acidity and negatively correlated with NH3 concentration, indicating that heterogeneous reactions were responsible for the observed NOC mass, possibly limited by liquid phase diffusion. Under these conditions, the data also indicate that the formation of NOC can compete kinetically with inorganic acid neutralization. The formation of NOC in this study suggests that a significant portion of the ambient particle associated N may be derived from NH3 heterogeneous reactions with SOA. NOC from such a mechanism may be an important and unaccounted for source of PM associated nitrogen, and a mechanism for medium or long-range transport and dry/wet deposition of atmospheric nitrogen.

  2. Formation of Secondary Organic Aerosol from Non-traditional Intermediate Volatility Organic Compounds

    NASA Astrophysics Data System (ADS)

    Donahue, N. M.; Presto, A. A.; Robinson, A. L.; Kroll, J. H.; Worsnop, D. R.

    2009-04-01

    Secondary organic aerosol (SOA) formation from 'traditional' precursors such as monoterpenes and alkylbenzenes has received substantial attention for the past decade. These traditional sources have relatively high emissions into the atmosphere, but they are also relatively volatile. As a consequence, the oxidation products from those precursors must be more than one million times less volatile in order to form SOA. We have recently begun to investigate the role of 'nontraditional' SOA precursors with much lower volatility than the traditional precursors. These intermediate volatility organic compounds (IVOC) are typically co-emitted with traditional primary organic aerosol (POA) sources at elevated temperatures, including biomass burning and internal combustion processes. While their emissions are much lower than the traditional precursors, the volatility reduction required of the reaction products is much less drastic, making high-yield SOA formation much more likely. Here we describe the formation of SOA from two precursors in the CMU environmental chamber - heptadecane and pentacosane - under high- and low-NOx conditions. Analysis of the resulting SOA with a high-resolution aerosol mass spectrometer coupled to a thermodenuder allows us to asses the oxidation state and volatility distribution of the condensible products, revealing a high degree of oxidation under high-NOx conditions where most of the organics remain in the vapor phase for at least 2 generations of oxidation chemistry, but a lower (though progressive) degree of oxidation under other conditions. These results will be place in context using a two-dimensional volatility basis set that incorporates both the volatility distribution and oxidation state of complex organic mixtures.

  3. Quantifying the ionic reaction channels in the Secondary Organic Aerosol formation from glyoxal

    NASA Astrophysics Data System (ADS)

    Maxut, Aurelia; Nozière, Barbara; Rossignol, Stéphanie; George, Christian; Waxman, Eleanor Marie; Laskin, Alexander; Slowik, Jay; Dommen, Josef; Prévôt, André; Baltensperger, Urs; Volkamer, Rainer

    2014-05-01

    Glyoxal, a common organic gas in the atmosphere, has been identified in recent years as an important Secondary Organic Aerosol (SOA) precursor (Volkamer et al., 2007). But, unlike with other precursors, the SOA is largely produced by particle-phase reactions (Volkamer et al., 2009) and equilibria (Kampf et al. 2013) that are still not entirely characterized. Since 2009 series of smog chamber experiments have been performed within the Eurochamp program at the Paul Scherrer Institute, Switzerland, to investigate SOA formation from glyoxal. In these experiments, glyoxal was produced by the gas-phase oxidation of acetylene in the presence of seeds, the seed composition and other conditions being varied. The 2011 campaign resulted in the identification of salting processes controlling the glyoxal partitioning in the seeds (Kampf et al. 2013). This presentation will report results of the 2013 campaign focusing on the identification of the various reactions (ionic or photo-induced) contributing to the SOA mass. In particular, the contribution of the ionic reactions, i.e. mediated by NH4+, were investigated by quantifying the formation of imidazoles (imidazole, imidazole-2-carboxaldehyde, 2,2'-biimidazole) from the small condensation channel of glyoxal with ammonia. For this, the SOA produced were collected on quartz filters and analyzed by Orbitrap LC/MS (Q-Exactive Thermo Fisher). The formation of other products such as organic acids was also investigated to determine potential competing reactions. Time-resolved MOUDI sampling coupled with nano-DESY/ESI-MS/MS analysis was also used to identify nitrogen- and sulphur-containing products from all the reactions. The results obtained for a range of conditions will be presented and compared with recent mechanistic information on the ionic reaction channels (Nozière et al., in preparation, 2013). The implementation of all this new information into a glyoxal-SOA model will be discussed.

  4. Limited Effect of Anthropogenic Nitrogen Oxides on Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Knote, C. J.; Tilmes, S.; Emmons, L. K.; Lamarque, J. F.; Yu, P.

    2014-12-01

    Globally secondary organic aerosol (SOA) is mostly formed from biogenic vegetation emissions and as such is regarded as natural aerosol that cannot be reduced by emission control legislation. However, recent research implies that human activities facilitate SOA formation by affecting the amount of precursor emission, the chemical processing and the partitioning into the aerosol phase. Among the multiple human influences, nitrogen oxides (NO + NO2 = NOx) have been assumed to play a critical role in the chemical formation of low volatile compounds. The goal of this study is to improve the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-Chem) by implementing an updated 4-product Volatility Basis Set (VBS) scheme, and apply it to investigate the impact of anthropogenic NOx on SOA. We first compare three different SOA parameterizations: a 2-product model and the updated VBS model both with and without a SOA aging parameterization. Secondly we evaluate predicted organic aerosol amounts against surface measurement from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network and Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns. We then perform sensitivity experiments to examine how the SOA loading responds to a 50% reduction in anthropogenic NOx in different regions. We find limited SOA reductions of -2.3%, -5.6% and -4.0% for global, southeastern U.S. and Amazon NOx perturbations, respectively. To investigate the chemical processes in more detail, we also use a simplified box model with the same gas-phase chemistry and gas-aerosol partitioning mechanism as in CAM4-Chem to examine the SOA yields dependence on initial precursor emissions and background NOx level. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- versus high-NOx pathways, OH versus NO3-initiated oxidation) and to offsetting

  5. Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Liggio, J.; Staebler, R.; Li, S.-M.

    2015-12-01

    As a class of brown carbon, organonitrogen compounds originating from the heterogeneous uptake of NH3 by secondary organic aerosol (SOA) have received significant attention recently. In the current work, particulate organonitrogen formation during the ozonolysis of α-pinene and the OH oxidation of m-xylene in the presence of ammonia (34-125 ppb) was studied in a smog chamber equipped with a high resolution time-of-flight aerosol mass spectrometer and a quantum cascade laser instrument. A large diversity of nitrogen-containing organic (NOC) fragments was observed which were consistent with the reactions between ammonia and carbonyl-containing SOA. Ammonia uptake coefficients onto SOA which led to organonitrogen compounds were reported for the first time, and were in the range of ∼ 10-3-10-2, decreasing significantly to < 10-5 after 6 h of reaction. At the end of experiments (~ 6 h) the NOC mass contributed 8.9 ± 1.7 and 31.5 ± 4.4 wt % to the total α-pinene- and m-xylene-derived SOA, respectively, and 4-15 wt % of the total nitrogen in the system. Uptake coefficients were also found to be positively correlated with particle acidity and negatively correlated with NH3 concentration, indicating that heterogeneous reactions were responsible for the observed NOC mass, possibly limited by liquid phase diffusion. Under these conditions, the data also indicate that the formation of NOC can compete kinetically with inorganic acid neutralization. The formation of NOC in this study suggests that a significant portion of the ambient particle associated N may be derived from NH3 heterogeneous reactions with SOA. NOC from such a mechanism may be an important and unaccounted for source of PM associated nitrogen. This mechanism may also contribute to the medium or long-range transport and wet/dry deposition of atmospheric nitrogen.

  6. Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)

    NASA Astrophysics Data System (ADS)

    Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Muñoz, A.; Vásquez, M.; Borrás, E.; Ródenas, M.

    2013-12-01

    The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high performance liquid chromatography mass spectrometry (HPLC-ITMS), high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18-29% depending on initial precursor (VOC : NOx) mixing ratios. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O : C ratios, where functionalisation rather than fragmentation is mainly observed as a~result of the stability of the ring. The SOA species observed can be characterized as semi-volatile to low volatile oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.

  7. Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)

    NASA Astrophysics Data System (ADS)

    Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Muñoz, A.; Vázquez, M.; Borrás, E.; Ródenas, M.

    2014-06-01

    The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound (VOC) that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high-performance liquid chromatography mass spectrometry (HPLC-ITMS), high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18 and 29% for an initial VOC mixing ratio of 212 and 460 ppbv (parts per billion by volume) respectively; using a VOC:NOx ratio of ~5:1. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high-resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro-functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O:C ratios, where functionalisation rather than fragmentation is mainly observed as a result of the stability of the ring. The SOA species observed can be characterised as semi-volatile to low-volatility oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.

  8. Secondary organic aerosol formation from ozone reactions with single terpenoids and terpenoid mixtures

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Wells, J. Raymond; Siegel, Jeffrey A.

    2011-08-01

    Ozone reacts with indoor-emitted terpenoids to form secondary organic aerosol (SOA). Most SOA research has focused on ozone reactions with single terpenoids or with consumer products, and this paper reports the results from an investigation of SOA formation from ozone reactions with both single terpenoids and mixtures of D-limonene, α-pinene, and α-terpineol. Transient experiments were conducted at low (25 ppb) and high (100 ppb) initial concentrations of ozone. The three terpenoids were tested singly and in combinations in a manner that controlled for their different reaction rates with ozone. The SOA formation was assessed by examining the evolution in time of the resulting number size-distributions and estimates of the mass concentrations. The results suggest that at higher ozone and terpenoid concentrations, SOA number formation follows a linear trend as a function of the initial rate of reaction. This finding was valid for both single terpenoids and mixtures. Generally speaking, higher ozone and terpenoid concentrations also led to larger geometric mean diameters and smaller geometric standard deviations of fitted lognormal distributions of the formed SOA. By assuming a density, mass concentrations were also assessed and did not follow as consistent of a trend. At low ozone concentration conditions, reactions with only D-limonene yielded the largest number concentrations of any experiment, even more than experiments with mixtures containing D-limonene and much higher overall terpenoid concentrations. This finding was not seen for high ozone concentrations. These experiments demonstrate quantifiable trends for SOA forming reactions of ozone and mixtures, and this work provides a framework for expanding these results to more complex mixtures and consumer products.

  9. High-Aluminum-Affinity Silica Is a Nanoparticle That Seeds Secondary Aluminosilicate Formation

    PubMed Central

    Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J.

    2013-01-01

    Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m2 g-1 and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates. PMID:24349573

  10. Dissection of the Transcriptional Program Regulating Secondary Wall Biosynthesis during Wood Formation in Poplar1[C][W][OA

    PubMed Central

    Zhong, Ruiqin; McCarthy, Ryan L.; Lee, Chanhui; Ye, Zheng-Hua

    2011-01-01

    Wood biomass is mainly made of secondary cell walls; hence, elucidation of the molecular mechanisms underlying the transcriptional regulation of secondary wall biosynthesis during wood formation will be instrumental to design strategies for genetic improvement of wood biomass. Here, we provide direct evidence demonstrating that the poplar (Populus trichocarpa) wood-associated NAC domain transcription factors (PtrWNDs) are master switches activating a suite of downstream transcription factors, and together, they are involved in the coordinated regulation of secondary wall biosynthesis during wood formation. We show that transgenic poplar plants with dominant repression of PtrWNDs functions exhibit a drastic reduction in secondary wall thickening in woody cells, and those with PtrWND overexpression result in ectopic deposition of secondary walls. Analysis of PtrWND2B overexpressors revealed up-regulation of the expression of a number of wood-associated transcription factors, the promoters of which were also activated by PtrWND6B and the Eucalyptus EgWND1. Transactivation analysis and electrophoretic mobility shift assay demonstrated that PtrWNDs and EgWND1 activated gene expression through direct binding to the secondary wall NAC-binding elements, which are present in the promoters of several wood-associated transcription factors and a number of genes involved in secondary wall biosynthesis and modification. The WND-regulated transcription factors PtrNAC150, PtrNAC156, PtrNAC157, PtrMYB18, PtrMYB74, PtrMYB75, PtrMYB121, PtrMYB128, PtrZF1, and PtrGATA8 were able to activate the promoter activities of the biosynthetic genes for all three major wood components. Our study has uncovered that the WND master switches together with a battery of their downstream transcription factors form a transcriptional network controlling secondary wall biosynthesis during wood formation. PMID:21908685

  11. Formation of Secondary Reaction Zones in Diffusion Aluminide-Coated Ni-Base Single-Crystal Superalloys Containing Ruthenium

    NASA Astrophysics Data System (ADS)

    Das, Dipak K.; Murphy, Kenneth S.; Ma, Shuwei; Pollock, Tresa M.

    2008-07-01

    The formation of secondary reaction zones (SRZs) beneath aluminide coatings in several Ru-bearing single-crystal Ni-base superalloys has been investigated. The presence of significant amounts of Ru in the superalloys did not prevent the formation of the secondary reaction zone. However, the Ru content of the alloys affected the type of refractory element-rich phase formed during the transformation. As the Ru content increased, the phase involved in the transformation shifted from the orthorhombic P to the β-RuAl phase. A differential tendency to SRZ formation was observed between the dendritic and interdendritic regions of the alloys. Significant growth of the SRZ was also observed during the high-temperature oxidation exposure of the coated alloys. The effects of the alloying elements on SRZ formation are discussed.

  12. Self-assembly through secondary interactions in formation of two-dimensional lead(II) supramolecular polymer with nanosheets morphology

    NASA Astrophysics Data System (ADS)

    Noori, Yasamin; Akhbari, Kamran; Phuruangrat, Anukorn; Costantino, Ferdinando

    2017-02-01

    In order to study the role of self-assembly through secondary interactions in formation of [Pb(3-AB)2]n (1), [3-ABbar = 3-aminobenzoate], we designed some experiments and synthesized two samples of 1 under ultrasonic irradiations. Nanosheets of 1 were synthesized under these conditions. Compound 1 is a one-dimensional coordination polymer. Self-assembly through hydrogen bonding and π-π stacking interactions between these chains results in formation of two-dimensional supramolecular polymer. It seems that self-assembly through secondary interactions between these chain structures is responsible for formation of 1 with nanosheet morphology. Formation nanoparticles of [Pb(2,6-DHB)2]n (2), [2,6-DHBbar = 2,6-dihydroxybenzoate], under the same condition applied for 1, which has three-dimensional coordination network in its crystalline structure, approved our hypotheses. These microstructures were characterized by IR spectroscopy, X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM).

  13. Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles

    NASA Astrophysics Data System (ADS)

    Gordon, T. D.; Presto, A. A.; May, A. A.; Nguyen, N. T.; Lipsky, E. M.; Donahue, N. M.; Gutierrez, A.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

    2014-05-01

    The effects of photochemical aging on emissions from 15 light-duty gasoline vehicles were investigated using a smog chamber to probe the critical link between the tailpipe and ambient atmosphere. The vehicles were recruited from the California in-use fleet; they represent a wide range of model years (1987 to 2011), vehicle types and emission control technologies. Each vehicle was tested on a chassis dynamometer using the unified cycle. Dilute emissions were sampled into a portable smog chamber and then photochemically aged under urban-like conditions. For every vehicle, substantial secondary organic aerosol (SOA) formation occurred during cold-start tests, with the emissions from some vehicles generating as much as 6 times the amount of SOA as primary particulate matter (PM) after 3 h of oxidation inside the chamber at typical atmospheric oxidant levels (and 5 times the amount of SOA as primary PM after 5 × 106 molecules cm-3 h of OH exposure). Therefore, the contribution of light-duty gasoline vehicle exhaust to ambient PM levels is likely dominated by secondary PM production (SOA and nitrate). Emissions from hot-start tests formed about a factor of 3-7 less SOA than cold-start tests. Therefore, catalyst warm-up appears to be an important factor in controlling SOA precursor emissions. The mass of SOA generated by photooxidizing exhaust from newer (LEV2) vehicles was a factor of 3 lower than that formed from exhaust emitted by older (pre-LEV) vehicles, despite much larger reductions (a factor of 11-15) in nonmethane organic gas emissions. These data suggest that a complex and nonlinear relationship exists between organic gas emissions and SOA formation, which is not surprising since SOA precursors are only one component of the exhaust. Except for the oldest (pre-LEV) vehicles, the SOA production could not be fully explained by the measured oxidation of speciated (traditional) SOA precursors. Over the timescale of these experiments, the mixture of organic vapors

  14. Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles

    NASA Astrophysics Data System (ADS)

    Gordon, T. D.; Presto, A. A.; May, A. A.; Nguyen, N. T.; Lipsky, E. M.; Donahue, N. M.; Gutierrez, A.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

    2013-09-01

    The effects of photochemical aging on emissions from 15 light-duty gasoline vehicles were investigated using a smog chamber to probe the critical link between the tailpipe and ambient atmosphere. The vehicles were recruited from the California in-use fleet; they represent a wide range of model years (1987 to 2011), vehicle types and emission control technologies. Each vehicle was tested on a chassis dynamometer using the unified cycle. Dilute emissions were sampled into a portable smog chamber and then photochemically aged under urban-like conditions. For every vehicle, substantial secondary organic aerosol (SOA) formation occurred during cold-start tests, with the emissions from some vehicles generating as much as 6 times the amount of SOA as primary particulate matter after three hours of oxidation inside the chamber at typical atmospheric oxidant levels. Therefore, the contribution of light duty gasoline vehicle exhaust to ambient PM levels is likely dominated by secondary PM production (SOA and nitrate). Emissions from hot-start tests formed about a factor of 3-7 less SOA than cold-start tests. Therefore, catalyst warm-up appears to be an important factor in controlling SOA precursor emissions. The mass of SOA generated by photo-oxidizing exhaust from newer (LEV1 and LEV2) vehicles was only modestly lower (38%) than that formed from exhaust emitted by older (pre-LEV) vehicles, despite much larger reductions in non-methane organic gas emissions. These data suggest that a complex and non-linear relationship exists between organic gas emissions and SOA formation, which is not surprising since SOA precursors are only one component of the exhaust. Except for the oldest (pre-LEV) vehicles, the SOA production could not be fully explained by the measured oxidation of speciated (traditional) SOA precursors. Over the time scale of these experiments, the mixture of organic vapors emitted by newer vehicles appear to be more efficient (higher yielding) in producing SOA than

  15. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    NASA Astrophysics Data System (ADS)

    Quan, Jiannong; Liu, Quan; Li, Xia; Gao, Yang; Jia, Xingcan; Sheng, Jiujiang; Liu, Yangang

    2015-12-01

    The effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) both significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60-80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly due to high emission and low reaction rate; the occurrence of heterogeneous aqueous reactions in the late haze period, together with the accumulated high concentrations of precursor gases such as SO2 and NOx, accelerated the formation of secondary

  16. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    SciTech Connect

    Quan, Jiannong; Liu, Yangang; Liu, Quan; Li, Xia; Gao, Yang; Jia, Xingcan; Sheng, Jiujiang

    2015-09-30

    In this study, the effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) both significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60–80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly

  17. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    DOE PAGES

    Quan, Jiannong; Liu, Yangang; Liu, Quan; ...

    2015-09-30

    In this study, the effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) bothmore » significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60–80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly due to high emission and low reaction rate; the occurrence of heterogeneous aqueous reactions in the late haze period, together with the accumulated high concentrations of precursor gases such as SO2 and NOx, accelerated the

  18. Secondary Aerosol Formation from Oxidation of Aromatics Hydrocarbons by Cl atoms

    NASA Astrophysics Data System (ADS)

    Cai, X.; Griffin, R.

    2006-12-01

    Aerosol Formation From the Oxidation of Aromatic Hydrocarbons by Chlorine Atmospheric secondary organic aerosol (SOA) affects regional and global air quality. The formation mechanisms of SOA via the oxidation of volatile organic compounds by hydroxyl radicals, ozone, and nitrate radicals have been studied intensively during the last decade. Chlorine atoms (Cl) also have been hypothesized to be effective oxidants in marine and industrially influenced areas. Recent work by the authors has indicated that significant amounts of SOA are formed from the oxidation of monoterpenes by Cl. Aromatic hydrocarbons are important for generation of both SOA and ozone in urban areas because of their large emission rates and high reactivity. The goal of this work was to quantify the SOA formation potentials of two representative aromatic hydrocarbons through laboratory chamber experiments in which oxidation was initiated by Cl. The system constructed for this study includes an experimental chamber, a gas chromatograph for quantification of aromatic mixing ratios, a Scanning Mobility Particle Spectrometer to measure SOA size distributions, a zero air generator, and an illuminating system. The model aromatic hydrocarbons chosen for this study are toluene and m-xylene. Aerosol yields are estimated based on measured aerosol volume concentration, the concentration of consumed hydrocarbon, and estimation of wall loss of the newly formed aerosol. Toluene and m-xylene exhibit similar SOA yields from the oxidation initiated by Cl. The toluene SOA yield from Cl-initiated oxidation, however, depends on the ratio between the mixing ratios of the initial chlorine source and toluene in the chamber. For toluene experiments with higher such ratios, SOA yields vary from 0.05 to 0.079 for generated aerosol ranging from 4.2 to12.0 micrograms per cubic meter. In the lower ratio experiments, SOA yields are from 0.033 to 0.064, corresponding to generated aerosol from 3.0 to 11.0 micrograms per cubic

  19. Impact of NOx and OH on secondary organic aerosol formation from β-pinene photooxidation

    NASA Astrophysics Data System (ADS)

    Sarrafzadeh, Mehrnaz; Wildt, Jürgen; Pullinen, Iida; Springer, Monika; Kleist, Einhard; Tillmann, Ralf; Schmitt, Sebastian H.; Wu, Cheng; Mentel, Thomas F.; Zhao, Defeng; Hastie, Donald R.; Kiendler-Scharr, Astrid

    2016-09-01

    In this study, the NOx dependence of secondary organic aerosol (SOA) formation from photooxidation of the biogenic volatile organic compound (BVOC) β-pinene was comprehensively investigated in the Jülich Plant Atmosphere Chamber. Consistent with the results of previous NOx studies we found increases of SOA yields with increasing [NOx] at low-NOx conditions ([NOx]0 < 30 ppb, [BVOC]0 / [NOx]0 > 10 ppbC ppb-1). Furthermore, increasing [NOx] at high-NOx conditions ([NOx]0 > 30 ppb, [BVOC]0 / [NOx]0 ˜ 10 to ˜ 2.6 ppbC ppb-1) suppressed the SOA yield. The increase of SOA yield at low-NOx conditions was attributed to an increase of OH concentration, most probably by OH recycling in NO + HO2 → NO2 + OH reaction. Separate measurements without NOx addition but with different OH primary production rates confirmed the OH dependence of SOA yields. After removing the effect of OH concentration on SOA mass growth by keeping the OH concentration constant, SOA yields only decreased with increasing [NOx]. Measuring the NOx dependence of SOA yields at lower [NO] / [NO2] ratio showed less pronounced increase in both OH concentration and SOA yield. This result was consistent with our assumption of OH recycling by NO and to SOA yields being dependent on OH concentrations. Our results furthermore indicated that NOx dependencies vary for different NOx compositions. A substantial fraction of the NOx-induced decrease of SOA yields at high-NOx conditions was caused by NOx-induced suppression of new particle formation (NPF), which subsequently limits the particle surface where low volatiles condense. This was shown by probing the NOx dependence of SOA formation in the presence of seed particles. After eliminating the effect of NOx-induced suppression of NPF and NOx-induced changes of OH concentrations, the remaining effect of NOx on the SOA yield from β-pinene photooxidation was moderate. Compared to β-pinene, the SOA formation from α-pinene photooxidation was only suppressed by

  20. Formation and Processing of Secondary Organic Aerosol from Catechol as a Model for Atmospheric HULIS

    NASA Astrophysics Data System (ADS)

    Ofner, Johannes; Krüger, Heinz-Ulrich; Grothe, Hinrich; Zetzsch, Cornelius

    2010-05-01

    A particular fraction of the secondary organic aerosol (SOA) termed HUmic Like Substances (HULIS) attracted attention only recently in atmospheric aerosol, initiating a discourse about their aromaticity and other properties, such as reactivity and hygroscopicity. A major portion of HULIS originates from volatile organic compounds, which are formed by abiotic oxidation reactions involving mainly OH radicals, ozone, nitrogen oxides and possibly halogens. Subsequently, the particles provide surface for heterogeneous reactions with atmospheric trace gases. Thus, aerosol smog-chamber studies with appropriate precursors are needed to generate SOA with HULIS qualities in situ inside the smog chamber and study their possible interactions. Catechol and guaiacol were chosen as aromatic precursors for synthetic HULIS production. The SOA was produced in a 700 L aerosol smog chamber, equipped with a solar simulator. SOA formation from each precursor was investigated at simulated environmental conditions (humidity, light, and presence of oxidizers) and characterized with respect to HULIS properties by particle classifiers, Fourier Transform IR spectroscopy (by long-path absorption and attenuated total reflection), UV/VIS spectroscopy, high-resolution mass-spectroscopy and temperature-programmed-desorption mass-spectrometry. High-resolution imaging was obtained using Field Emission Gun Scanning Electron Microscopy (FEGSEM). After HULIS formation the aerosol particles were exposed to atmospheric halogen species to study their processing with those trace gases, released by sea salt-activation. Those investigations show that aromatic precursors like catechol and guaiacol are suitable to form synthetic HULIS for laboratory-scale measurements with physical and chemical properties described in literature. However, sunlight and relative humidity play a major role in particle production and composition of functional groups, which are the anchor points for heterogeneous atmospheric

  1. Secondary organic aerosol formation from gasoline passenger vehicle emissions investigated in a smog chamber

    NASA Astrophysics Data System (ADS)

    Nordin, E. Z.; Eriksson, A. C.; Roldin, P.; Nilsson, P. T.; Carlsson, J. E.; Kajos, M. K.; Hellén, H.; Wittbom, C.; Rissler, J.; Löndahl, J.; Swietlicki, E.; Svenningsson, B.; Bohgard, M.; Kulmala, M.; Hallquist, M.; Pagels, J.

    2012-12-01

    Gasoline vehicles have elevated emissions of volatile organic compounds during cold starts and idling and have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from one Euro II, one Euro III and one Euro IV passenger vehicles were investigated using photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out at atmospherically relevant organic aerosol mass concentrations. The characterization methods included a high resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind urban areas. After 4 h aging the formed SOA was 1-2 orders of magnitude higher than the Primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 4 3) approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6-C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher order aromatic compounds such as C10, C11 light aromatics, naphthalene and methyl-naphthalenes.

  2. Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

    2015-08-01

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

  3. Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

    2015-12-01

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for the no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9-5.6, 6.4-12.0 and 0.9-2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

  4. Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

    DOE PAGES

    Zheng, Y.; Unger, N.; Hodzic, A.; ...

    2015-08-28

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution ofmore » US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

  5. Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

    DOE PAGES

    Zheng, Y.; Unger, N.; Hodzic, A.; ...

    2015-12-08

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for themore » no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9–5.6, 6.4–12.0 and 0.9–2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

  6. Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber

    NASA Astrophysics Data System (ADS)

    Platt, S. M.; El Haddad, I.; Zardini, A. A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J. G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; Drinovec, L.; Močnik, G.; Möhler, O.; Richter, R.; Barmet, P.; Bianchi, F.; Baltensperger, U.; Prévôt, A. S. H.

    2013-09-01

    We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of different emission sources without limitation from the instruments or facilities available at any single site. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric aging of emissions may be simulated over a range of temperatures (-7 to 25 °C). A photolysis rate of NO2, JNO2, of (8.0 ± 0.7) × 10-3 s-1 was determined at 25 °C. We demonstrate the utility of this new system by presenting results on the aging (OH = 12 × 106 cm-3 h) of emissions from a modern (Euro 5) gasoline car operated during a driving cycle (New European Driving Cycle, NEDC) on a chassis dynamometer in a vehicle test cell. Emissions from the entire NEDC were sampled and aged in the chamber. Total organic aerosol (OA; primary organic aerosol (POA) emission + secondary organic aerosol (SOA) formation) was (369.8-397.5)10-3 g kg-1 fuel, or (13.2-15.4) × 10-3 g km-1, after aging, with aged OA/POA in the range 9-15. A thorough investigation of the composition of the gas phase emissions suggests that the observed SOA is from previously unconsidered precursors and processes. This large enhancement in particulate matter mass from gasoline vehicle aerosol emissions due to SOA formation, if it occurs across a wider range of gasoline vehicles, would have significant implications for our understanding of the contribution of on-road gasoline vehicles to ambient aerosols.

  7. Preferred Social Organization of Learning Formats among Pupils Experiencing Different Kinds of Internalizing Problems in Secondary School

    ERIC Educational Resources Information Center

    Paulsen, Erik; Bru, Edvin

    2008-01-01

    The aims of this study were to investigate the dimensionality of internalizing problems among secondary high school pupils and to find out about their preferences for the social organization of learning formats. We wanted to see if preferences varied for pupils reporting different kinds of internalizing problems. Five hundred and one pupils in…

  8. SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS IN THE PRESENCE OF DRY SUBMICRON AMMONIUM SULFATE AEROSOL

    EPA Science Inventory

    A laboratory study was conducted to examine formation of secondary organic aerosols. A smog chamber system was developed for studying gas-aerosol interactions in a dynamic flow reactor. These experiments were conducted to investigate the fate of gas and aerosol phase compounds ...

  9. Mechanism Underlying the Spatial Pattern Formation of Dominant Tree Species in a Natural Secondary Forest

    PubMed Central

    Jia, Guodong; Yu, Xinxiao; Fan, Dengxing; Jia, Jianbo

    2016-01-01

    Studying the spatial pattern of plant species may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley’s L(r) functions were employed to evaluate intra-/interspecific relationships of four dominant tree species (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono) and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of trees. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large trees did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer trees occurred among other species, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined. PMID:27028757

  10. Secondary effects of catalytic diesel particulate filters: copper-induced formation of PCDD/Fs.

    PubMed

    Heeb, Norbert V; Zennegg, Markus; Gujer, Erika; Honegger, Peter; Zeyer, Kerstin; Gfeller, Urs; Wichser, Adrian; Kohler, Martin; Schmid, Peter; Emmenegger, Lukas; Ulrich, Andrea; Wenger, Daniela; Petermann, Jean-Luc; Czerwinski, Jan; Mosimann, Thomas; Kasper, Markus; Mayer, Andreas

    2007-08-15

    Potential risks of a secondary formation of polychlorinated dibenzodioxins/furans (PCDD/Fs) were assessed for two cordierite-based, wall-through diesel particulate filters (DPFs) for which soot combustion was either catalyzed with an iron- or a copper-based fuel additive. A heavy duty diesel engine was used as test platform, applying the eight-stage ISO 8178/4 C1 cycle. DPF applications neither affected the engine performance, nor did they increase NO, NO2, CO, and CO2 emissions. The latter is a metric for fuel consumption. THC emissions decreased by about 40% when deploying DPFs. PCDD/F emissions, with a focus on tetra- to octachlorinated congeners, were compared under standard and worst case conditions (enhanced chlorine uptake). The iron-catalyzed DPF neither increased PCDD/F emissions, nor did it change the congener pattern, even when traces of chlorine became available. In case of copper, PCDD/F emissions increased by up to 3 orders of magnitude from 22 to 200 to 12 700 pg I-TEQ/L with fuels of < 2, 14, and 110 microg/g chlorine, respectively. Mainly lower chlorinated DD/Fs were formed. Based on these substantial effects on PCDD/F emissions, the copper-catalyzed DPF system was not approved for workplace applications, whereas the iron system fulfilled all the specifications of the Swiss procedures for DPF approval (VERT).

  11. Carbon Catabolite Regulation of Secondary Metabolite Formation and Morphological Differentiation in Streptomyces coelicolor.

    PubMed

    Romero-Rodríguez, A; Ruiz-Villafán, B; Tierrafría, V H; Rodríguez-Sanoja, R; Sánchez, S

    2016-11-01

    In the genus Streptomyces, carbon utilization is of significant importance for the expression of genes involved in morphological differentiation and antibiotic production. However, there is little information about the mechanism involved in these effects. In the present work, it was found that glucose exerted a suppressive effect on the Streptomyces coelicolor actinorhodin (Act) and undecylprodigiosin (Red) production, as well as in its morphological differentiation. Accordingly, using a high-density microarray approach in S. coelicolor grown under glucose repression, at early growth stages, a negative effect was exerted on the transcription of genes involved in Act and Red production, when compared with non-repressive conditions. Seven genes of Act and at least ten genes of Red production were down-regulated by glucose. Stronger repression was observed on the initial steps of antibiotics formation. On the contrary, the coelimycin P1 cluster was up-regulated by glucose. Regarding differentiation, no sporulation was observed in the presence of glucose and expression of a set of genes of the bld cascade was repressed as well as chaplins and rodlins genes. Finally, a series of transcriptional regulators involved in both processes were up- or down-regulated by glucose. This is the first global transcriptomic approach performed to understand the molecular basis of the glucose effect on the synthesis of secondary metabolism and differentiation in the genus Streptomyces. The results of this study are opening new avenues for further exploration.

  12. "To-and-fro" waveform in the diagnosis of arterial pseudoaneurysms.

    PubMed

    Mahmoud, Mustafa Z; Al-Saadi, Mohammed; Abuderman, Abdulwahab; Alzimami, Khalid S; Alkhorayef, Mohammed; Almagli, Babikir; Sulieman, Abdelmoneim

    2015-05-28

    Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography (DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of "to-and-fro" waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of "to-and-fro" waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and "to-and-fro" flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional "to-and-fro" waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the "to-and-fro" waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.

  13. "To-and-fro" waveform in the diagnosis of arterial pseudoaneurysms

    PubMed Central

    Mahmoud, Mustafa Z; Al-Saadi, Mohammed; Abuderman, Abdulwahab; Alzimami, Khalid S; Alkhorayef, Mohammed; Almagli, Babikir; Sulieman, Abdelmoneim

    2015-01-01

    Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of “to-and-fro” waveform at duplex Doppler ultrasonography (DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of “to-and-fro” waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of “to-and-fro” waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and “to-and-fro” flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional “to-and-fro” waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the “to-and-fro” waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative. PMID:26029351

  14. Analysis of secondary growth in the Arabidopsis shoot reveals a positive role of jasmonate signalling in cambium formation

    PubMed Central

    Sehr, Eva M; Agusti, Javier; Lehner, Reinhard; Farmer, Edward E; Schwarz, Martina; Greb, Thomas

    2010-01-01

    After primary growth, most dicotyledonous plants undergo secondary growth. Secondary growth involves an increase in the diameter of shoots and roots through formation of secondary vascular tissue. A hallmark of secondary growth initiation in shoots of dicotyledonous plants is the initiation of meristematic activity between primary vascular bundles, i.e. in the interfascicular regions. This results in establishment of a cylindrical meristem, namely the vascular cambium. Surprisingly, despite its major implications for plant growth and the accumulation of biomass, the molecular regulation of secondary growth is only poorly understood. Here, we combine histological, molecular and genetic approaches to characterize interfascicular cambium initiation in the Arabidopsis thaliana inflorescence shoot. Using genome-wide transcriptional profiling, we show that stress-related and touch-inducible genes are up-regulated in stem regions where secondary growth takes place. Furthermore, we show that the products of COI1, MYC2, JAZ7 and the touch-inducible gene JAZ10, which are components of the JA signalling pathway, are cambium regulators. The positive effect of JA application on cambium activity confirmed a stimulatory role of JA in secondary growth, and suggests that JA signalling triggers cell divisions in this particular context. PMID:20579310

  15. Analysis of secondary growth in the Arabidopsis shoot reveals a positive role of jasmonate signalling in cambium formation.

    PubMed

    Sehr, Eva M; Agusti, Javier; Lehner, Reinhard; Farmer, Edward E; Schwarz, Martina; Greb, Thomas

    2010-09-01

    After primary growth, most dicotyledonous plants undergo secondary growth. Secondary growth involves an increase in the diameter of shoots and roots through formation of secondary vascular tissue. A hallmark of secondary growth initiation in shoots of dicotyledonous plants is the initiation of meristematic activity between primary vascular bundles, i.e. in the interfascicular regions. This results in establishment of a cylindrical meristem, namely the vascular cambium. Surprisingly, despite its major implications for plant growth and the accumulation of biomass, the molecular regulation of secondary growth is only poorly understood. Here, we combine histological, molecular and genetic approaches to characterize interfascicular cambium initiation in the Arabidopsis thaliana inflorescence shoot. Using genome-wide transcriptional profiling, we show that stress-related and touch-inducible genes are up-regulated in stem regions where secondary growth takes place. Furthermore, we show that the products of COI1, MYC2, JAZ7 and the touch-inducible gene JAZ10, which are components of the JA signalling pathway, are cambium regulators. The positive effect of JA application on cambium activity confirmed a stimulatory role of JA in secondary growth, and suggests that JA signalling triggers cell divisions in this particular context.

  16. Secondary inorganic aerosol formation and its shortwave direct radiative forcing in China

    NASA Astrophysics Data System (ADS)

    Huang, Xin

    2015-04-01

    Secondary inorganic aerosol (SIA), including sulfate, nitrate and ammonium, is an important part of fine particle. SIA plays a significant role in shortwave radiation transfer. Numerical simulation is usually used to study SIA formation and its climate effect. In this work, we used the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to study SIA formation and its direct radiative forcing (DRF) over China. SO2 oxidation pathways related to mineral aerosol, including transition metal-catalyzed oxidation in aqueous phase and heterogeneous reactions, play an important role in sulfate production, but they are not well treated in current atmospheric models. In this work, we improved the WRF-Chem model by simulating the enhancement role of mineral aerosol in sulfate production. Firstly, we estimated mineral cations based on local measurements in order to well represent aqueous phase acidity. Secondly, we scaled the transition metal concentration to the mineral aerosol levels according to the existing observations and improved transition metal-catalyzed oxidation calculation. Lastly, heterogeneous reactions of acid gases on the surface of mineral aerosol were included in this simulation. Accuracy in the prediction of sulfate by the model was significantly improved and we concluded that mineral aerosol can facilitate SO2 oxidation and subsequent sulfate formation. It was demonstrated that, over China, mineral aerosol was responsible for 21.8% of annual mean sulfate concentration. The enhanced aqueous oxidation was more significant compared to the heterogeneous reactions. In winter, mineral aerosol was responsible for 39.6% of sulfate production. In summer, gaseous oxidation and aqueous oxidation of SO2 by hydrogen peroxide and ozone were the dominant pathways of sulfate formation. Mineral aerosol only contributed 11.9% to the total sulfate production. The increase in annual mean sulfate concentration due to mineral aerosol could reach up to over 6

  17. New technique for treatment of postcatheterization radial artery pseudoaneurysm

    PubMed Central

    Pancholy, Samir B.; Kartashov, Dmitriy S.

    2016-01-01

    We report a new technique for treatment of radial artery pseudoaneurysm (RAP) caused by transradial access (TRA) for coronary angiography. Traditional extrinsic compression with radial flow cessation leads to a local milieu likely associated with an increase in probability of radial artery occlusion (RAO). Our technique involves obtaining ipsilateral radial artery access distal to the neck of the RAP followed by a prolonged sheath dwell time covering the neck of the RAP which allows the RAP sac to thrombose and maintains radial artery lumen patency. © 2016 The Authors. Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc. PMID:27527608

  18. Radiofrequency Ablation for Iatrogenic Thyroid Artery Pseudoaneurysm: Initial Experience.

    PubMed

    Jun, Ye Kyeong; Jung, So Lyung; Byun, Ho Kyun; Baek, Jung Hwan; Sung, Jin Yong; Sim, Jung Suk

    2016-10-01

    Eight iatrogenic thyroid pseudoaneurysms (ITPAs) after thyroid biopsy are reported. The mean ITPA diameter was 7.2 mm (range 4 to 12 mm). Ultrasound (US)-guided compression was initially performed at the neck of the ITPA in all cases. Among them, 4 ITPAs persisted (50%) in which radiofrequency (RF) ablation was performed. Mean RF ablation time and power were 13.5 seconds (range 5 to 24 seconds) and 20 W (range 10 to 50 W), respectively. All 4 cases were treated with RF ablation without any complications.

  19. Common carotid artery pseudoaneurysm after neck dissection: colour Doppler ultrasound and multidetector computed tomography findings.

    PubMed

    Flor, N; Sardanelli, F; Ghilardi, G; Tentori, A; Franceschelli, G; Felisati, G; Cornalba, G P

    2007-05-01

    Common carotid artery pseudoaneurysm is a rare disease, which has been previously unreported in association with neck dissection. We describe the Doppler ultrasound and multidetector computed tomography (CT) findings of a case of carotid pseudoaneurysm, one month after pharyngolaryngectomy with bilateral neck dissection. Multidetector CT confirmed the diagnosis made on the basis of Doppler ultrasound; the high image quality of axial and three-dimensional reconstructions avoided the need for pre-operative conventional angiography. In the presence of a pulsatile cervical mass after neck surgery, pseudoaneurysm of the carotid artery should be included in the differential diagnosis, and multidetector CT can be the sole pre-operative diagnostic imaging modality.

  20. Case of Pseudoaneurysm Mimicking a Soft Tissue Sarcoma: A Diagnostic Pitfall

    PubMed Central

    ALBERT, Sandeep; DANIEL, Sanju; GOUSE, Mohamad; CHERIAN, Vinu Mathew

    2015-01-01

    Pseudoaneurysms represent a pulsating encapsulated hematoma in communication with the lumen of a ruptured vessel. We present a 33-year-old male with a pseudoaneurysm of the profunda femoris artery. At presentation and on further evaluation, he was diagnosed with a possible soft tissue sarcoma of the distal thigh. Catastrophic haemorrhage occurred at the time of a planned, elective open biopsy. This case report emphasises the importance of considering pseudoaneurysm as a crucial differential diagnosis in atypical swellings and scrutinising all suspected soft tissue tumours with a contrast study or a Doppler ultrasound. PMID:26023297

  1. Diagnosis of pseudoaneurysm of the ascending aorta by pulsed Doppler cross sectional echocardiography.

    PubMed Central

    Wendel, C H; Cornman, C R; Dianzumba, S B

    1985-01-01

    Pseudoaneurysms of the ascending aorta are relatively uncommon compared with those evolving from the left ventricle. In a young man with endocarditis of the aortic valve who developed a pseudoaneurysm arising from the ascending aorta, the diagnosis was established with the pulsed Doppler technique and cross sectional echocardiography by passing the Doppler sample from the aorta through the neck of the false aneurysm into the large pseudoaneurysm. Aortic root angiography showed this connexion to be a small fistula between the aorta and right atrium. Necropsy findings confirmed the diagnosis. Images PMID:3994873

  2. Delayed rupture of a pseudoaneurysm in the brachial artery of a burn reconstruction patient

    PubMed Central

    2013-01-01

    A brachial artery pseudoaneurysm is a rare but serious condition that can be limb threatening. A number of reports have found that it may be the result of damage to the blood vessels around the brachial artery, either directly or indirectly, due to trauma or systemic diseases. We present our experience of delayed pseudoaneurysm rupture of the brachial artery in a rehabilitation patient with burns of the upper extremity who underwent fasciotomy and musculocutaneous flap coverage. We also provide a review of the brachial artery pseudoaneurysm. PMID:23758847

  3. Left Ventricular Pseudoaneurysm Following Inferior Myocardial Infarction: A Case for Conservative Management

    PubMed Central

    Ludmir, Jonathan; Kapoor, Karan; George, Praveen; Khural, Jasjeet; Barr, Brian

    2016-01-01

    Left ventricular pseudoaneurysm is a rare complication of myocardial infarction that carries a high mortality rate. Although conventional wisdom suggests prompt surgical repair in order to mitigate risk of expansion and rupture, there are some data to support non-operative management in asymptomatic individuals with likely chronic pseudoaneurysms, particularly when surgical candidacy is poor. We present a case of a medically managed left ventricular pseudoaneurysm subsequent to inferior ST-segment elevation myocardial infarction with 6-month follow-up data. PMID:28197266

  4. Intrarenal artery pseudoaneurysm after blunt abdominal trauma: a case report of successful superselective angioembolization

    PubMed Central

    Antunes-Lopes, T; Pinto, R; Morgado, P; Madaleno, P; Silva, J; Silva, C; Cruz, F

    2014-01-01

    Renal artery pseudoaneurysm is a very rare complication after blunt trauma injury. We report on a case of a 54-year-old man admitted to our hospital for right flank pain and gross hematuria, 5 days after blunt abdominal trauma. The diagnosis of interlobar renal pseudoaneurysm was established by a computed tomography scan and confirmed by angiography. Successful superselective angioembolization was performed. This radiographic intervention is an effective and minimally invasive technique to stop active bleeding from renal artery pseudoaneurysms, when patients are hemodynamically stable and where technically feasible. A review of the literature was carried out. PMID:24809039

  5. Percutaneous Thrombin Injection to Complete SMA Pseudoaneurysm Exclusion After Failing of Endograft Placement

    SciTech Connect

    Szopinski, Piotr Ciostek, Piotr; Pleban, Eliza; Iwanowski, Jaroslaw; Krol, Malgorzata Serafin-; Marianowska, Agnieszka; Noszczyk, Wojciech

    2005-05-15

    Visceral aneurysms are potentially life-threatening vascular lesions. Superior mesenteric artery (SMA) pseudoaneurysms are a rare but well-recognized complication of chronic pancreatitis. Open surgical repair of such an aneurysm, especially in patients after previous surgical treatment, might be dangerous and risky. Stent graft implantation makes SMA pseudoaneurysm exclusion possible and therefore avoids a major abdominal operation. Percutaneous direct thrombin injection is also one of the methods of treating aneurysms in this area. We report a first case of percutaneous ultrasound-guided thrombin injection to complete SMA pseudoaneurysm exclusion after an unsuccessful endograft placement. Six-month follow-up did not demonstrate any signs of aneurysm recurrence.

  6. Treatment of Infected Pseudoaneurysm of Femoral Artery after Vascular Closure Device Deployment: A Practical Solution

    PubMed Central

    Matic, Predrag; Babic, Srdjan; Tanaskovic, Slobodan; Jocic, Dario; Radak, Djordje

    2012-01-01

    Like other invasive procedures, percutaneous coronary interventions are associated with complications. Most common access site for these procedures is common femoral artery. Complications such as groin and retroperitoneal hematoma can be encountered as well as pseudoaneurysms, arteriovenous fistulas, acute arterial occlusion, and infection. When infected pseudoaneurysm occurs, surgical treatment can be extremely difficult. We present a case of the patient in whom infected pseudoaneurysm of common femoral artery developed after percutaneous coronary intervention and was successfully treated by surgical excision and autoarterial graft insertion. PMID:23119221

  7. Mechanisms for secondary eyewall formation, and cold-air damming: Tropical cyclone interactions

    NASA Astrophysics Data System (ADS)

    Garcia-Rivera, Jose Manuel

    This dissertation consists of two topics, the mechanisms leading to secondary eyewall formation in tropical cyclones, and effects of tropical cyclone---cold-air interactions on heavy precipitation. The first research topic involves a proposed coupled mechanism for secondary eyewall formation (SEF; initiation of an eyewall replacement cycle), using a WRF-ARW simulation of Hurricane Katrina (2005). The storm underwent a series of structural changes that were deemed necessary for the cycle to begin. These included a significant increase of rainband activity in the SEF region and the eventual vertical coupling of azimuthal-mean updrafts that led to cycle initiation. Increased rainband activity outside the primary eyewall in the hours before was mostly related to an intensifying main feeder band. Close to initiation, an updraft (explained by a pre-existing hypothesis) emerged outside the primary eyewall near the top of the boundary layer (BL). This updraft then intensified and extended both upward and outward, while the storm intensified and approached SEF. Eventually, the updraft coupled with the upward motion associated with rainband-related convection near the SEF radius. Once the alignment occurred, the deep updraft quickly organized to support deep convection that led to SEF within hours of initiation. The coupling of updrafts emanating from the BL with the environmental upward motion associated with the pre-existing rainband activity is proposed to be the key for SEF initiation in this case. The second topic investigates the interactions between an Appalachian cold-air damming event and the near-passage of Tropical Storm Kyle (2002) along the coastal Carolinas, as assessed by using a numerical weather prediction model. While the storm moved along the coastline, it began extra-tropical transition, bringing heavy rains to both the coastal region and inland towards the Piedmont of North Carolina. Our goal is to quantify the effects of both interacting weather systems

  8. Importance of Aqueous-phase Secondary Organic Aerosol Formation from Aromatics in an Atmospheric Hydrocarbon Mixture

    NASA Astrophysics Data System (ADS)

    Parikh, H. M.; Carlton, A. G.; Vizuete, W.; Zhang, H.; Zhou, Y.; Chen, E.; Kamens, R. M.

    2010-12-01

    Two new secondary organic aerosol (SOA) modeling frameworks are developed, one based on an aromatic gas and particle-phase kinetic mechanism and another based on a parameterized SOA model used in conjunction with an underlying gas-phase mechanism, both of which simulate SOA formation through partitioning to two stable liquid phases: one hydrophilic containing particle aqueous-phase and the other hydrophobic comprising mainly organic components. The models were evaluated against outdoor smog chamber experiments with different combinations of initial toluene, o-xylene, p-xylene, toluene and xylene mixtures, NOx, non-SOA-forming hydrocarbon mixture, initial seed type, and humidity. Aerosol data for experiments with either ammonium sulfate or initial background seed particles, in the presence of an atmospheric hydrocarbon mixture, NOx and in sunlight under a dry atmosphere (RH = 6 to 10%) show reduced SOA formation when compared to experiments with similar initial gas and particle concentrations at higher relative humidities (RH = 40 to 90%). Both frameworks simulated reasonable fits to the total observed SOA concentrations under all conditions. For both dry and wet experiments with low initial seed, semi-volatile product partitioning in particle organic-phase is mass-transfer limited and is modeled using a dynamic gas-particle partitioning algorithm with accommodation coefficient as the primary pseudo-transport parameter. Further, the modeled SOA product distributions for both frameworks clearly show the importance of the contribution of aqueous-phase SOA particularly under conditions of low initial seed concentrations and high-humidity. For both models, under these conditions, aqueous-phase SOA from uptake of glyoxal, methylglyoxal and related polar products to particle water phase dominates as compared to the partitioning of semi-volatiles to particle organic phase. Interestingly, both the kinetic and parameterized SOA frameworks simulate similar amounts of aqueous

  9. Novel methods for predicting gas-particle partitioning during the formation of secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Wania, F.; Lei, Y. D.; Wang, C.; Abbatt, J. P. D.; Goss, K.-U.

    2014-12-01

    Several methods have been presented in the literature to predict an organic chemical's equilibrium partitioning between the water insoluble organic matter (WIOM) component of aerosol and the gas phase, Ki,WIOM, as a function of temperature. They include (i) polyparameter linear free energy relationships calibrated with empirical aerosol sorption data, as well as (ii) the solvation models implemented in SPARC and (iii) the quantum-chemical software COSMOtherm, which predict solvation equilibria from molecular structure alone. We demonstrate that these methods can be used to predict Ki,WIOM for large numbers of individual molecules implicated in secondary organic aerosol (SOA) formation, including those with multiple functional groups. Although very different in their theoretical foundations, these methods give remarkably consistent results for the products of the reaction of normal alkanes with OH, i.e. their partition coefficients Ki,WIOM generally agree within one order of magnitude over a range of more than ten orders of magnitude. This level of agreement is much better than that achieved by different vapour pressure estimation methods that are more commonly used in the SOA community. Also, in contrast to the agreement between vapour pressure estimates, the agreement between the Ki,WIOM estimates does not deteriorate with increasing number of functional groups. Furthermore, these partitioning coefficients Ki,WIOM predicted SOA mass yields in agreement with those measured in chamber experiments of the oxidation of normal alkanes. If a Ki,WIOM prediction method was based on one or more surrogate molecules representing the solvation properties of the mixed OM phase of SOA, the choice of those molecule(s) was found to have a relatively minor effect on the predicted Ki,WIOM, as long as the molecule(s) are not very polar. This suggests that a single surrogate molecule, such as 1-octanol or a hypothetical SOA structure proposed by Kalberer et al. (2004), may often be

  10. Novel methods for predicting gas-particle partitioning during the formation of secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Wania, F.; Lei, Y. D.; Wang, C.; Abbatt, J. P. D.; Goss, K.-U.

    2014-08-01

    Several methods have been presented in the literature to predict an organic chemical's equilibrium partitioning between the water insoluble organic matter (WIOM) component of aerosol and the gas phase, Ki, WIOM as a function of temperature. They include (i) polyparameter linear free energy relationships calibrated with empirical aerosol sorption data, as well as (ii) the solvation models implemented in SPARC and (iii) the quantum-chemical software Cosmotherm, which predict solvation equilibria from molecular structure alone. We demonstrate that these methods can be used to predict Ki, WIOM for large numbers of individual molecules implicated in secondary organic aerosol (SOA) formation, including those with multiple functional groups. Although very different in their theoretical foundations, these methods give remarkably consistent results for the products of the reaction of normal alkanes with OH, i.e. their partition coefficients Ki, WIOM generally agree within one order of magnitude over a range of more than ten orders of magnitude. This level of agreement is much better than that achieved by different vapour pressure estimation methods that are more commonly used in the SOA community. Also, in contrast to the agreement between vapour pressure estimates, that between the Ki, WIOM estimates does not deteriorate with increasing number of functional groups. Furthermore, these partitioning coefficients Ki, WIOM are found to predict the SOA mass yield in chamber experiments of the oxidation of normal alkanes as good or better than a vapour pressure based method. If a Ki, WIOM prediction method was based on one or more surrogate molecules representing the solvation properties of the mixed OM phase of SOA, the choice of those molecule(s) was found to have a relatively minor effect on the predicted Ki, WIOM, as long as the molecule(s) are not very polar. This suggests that a single surrogate molecule, such as 1-octanol or a hypothetical SOA structure proposed by

  11. Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber

    NASA Astrophysics Data System (ADS)

    Platt, S. M.; El Haddad, I.; Zardini, A. A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J. G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; Drinovec, L.; Močnik, G.; Möhler, O.; Richter, R.; Barmet, P.; Bianchi, F.; Baltensperger, U.; Prévôt, A. S. H.

    2012-10-01

    We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of aerosols from different emissions sources without limitation from the instruments or facilities available at any single site. The chamber can be mounted on a trailer for transport to host facilities or for mobile measurements. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric photochemistry can be accurately simulated over a range of temperatures from -7-25 °C. A photolysis rate of NO2, JNO2, of (8.0 ± 0.7) × 10-3 molecules cm-3 s-1 was determined at 25 °C. Further, we present the first application of the mobile chamber and demonstrate its utility by quantifying primary organic aerosol (POA) emission and secondary organic aerosol (SOA) production from a Euro 5 light duty gasoline vehicle. Exhaust emissions were sampled during the New European Driving Cycle (NEDC), the standard driving cycle for European regulatory purposes, and injected into the chamber. The relative concentrations of oxides of nitrogen (NOx) and total hydrocarbon (THC) during the aging of emissions inside the chamber were controlled using an injection system developed as a part of the new mobile chamber set up. Total OA (POA + SOA) emission factors of (370 ± 18) × 10-3 g kg-1 fuel, or (14.6 ± 0.8) × 10-3 g km-1, after aging, were calculated from concentrations measured inside the smog chamber during two experiments. The average SOA/POA ratio for the two experiments was 15.1, a much larger increase than has previously been seen for diesel vehicles, where smog chamber studies have found SOA/POA ratios of 1.3-1.7. Due to this SOA formation, carbonaceous particulate matter (PM) emissions from a gasoline vehicle may approach those of a diesel vehicle of the same class. Furthermore, with the advent of emission controls requiring the use of diesel particle filters, gasoline vehicle emissions

  12. Cross-over: a generalizable phenomenon necessary for secondary intraneural ganglion cyst formation.

    PubMed

    Spinner, Robert J; Amrami, Kimberly K; Wang, Huan; Kliot, Michel; Carmichael, Stephen W

    2008-03-01

    . The injection study also demonstrated the cross-over phenomenon and produced a similar pattern as the cyst dissection. This article illustrates that cross-over can occur in another nerve (apart from the prototype fibular nerve). Furthermore, understanding the more complex anatomic nature of the upper trunk cross-over model provides insight into important mechanistic information regarding the bidirectional propagation patterns and formation of primary and secondary intraneural ganglion cysts not afforded by the previously described sciatic nerve cross-over model.

  13. Secondary organic aerosol formation during the photooxidation of toluene: NOx dependence of chemical composition.

    PubMed

    Sato, Kei; Hatakeyama, Shiro; Imamura, Takashi

    2007-10-04

    The photooxidation of toluene is a potential source of secondary organic aerosol (SOA) in urban air, but only a small portion of the compounds present in SOA have been identified. In this study, we analyzed the chemical compositions of SOA produced by photoirradiation of the toluene/NOx/air system in laboratory chamber experiments by a combination of liquid chromatography-mass spectrometry, hybrid high-performance liquid chromatography-mass spectrometry, and iodometry-spectrophotometry. The dependence of the chemical composition on the initial NOx concentration was examined at initial NO concentrations ([NO]0) of 0.2 and 1 ppmv. Fifteen semivolatile products, including aromatic and ring-cleavage compounds, were quantified. However, the quantified products comprised only a small portion ( approximately 1 wt %) of the total aerosol mass. The total SOA yield ( approximately 13 wt %), the ratio of organic peroxides to total SOA mass ( approximately 17 wt %), and the density of SOA ( approximately 1.4 g cm-3) were independent of the NOx level, suggesting that the reaction mechanisms of the formation of major SOA products at [NO]0 = 0.2 and 1 ppmv are essentially the same. The negative-ion mass spectra of SOA samples showed that ion signals attributed to hemiacetal oligomers and/or decomposition products of peroxy hemiacetal oligomers were detected in the range of mass-to-charge ratios (m/z) between 200 and 500. The highest signals were detected at m/z = 155 and 177, and these were tentatively assigned to C7 unsaturated oxacyclic oxocarboxylic acids and C7 unsaturated oxacyclic dicarboxylic acids, respectively. We conclude that the major chemical components of the aerosol are hemiacetal and peroxy hemiacetal oligomers and low-molecular-weight dicarboxylic acids.

  14. Delayed recurrent nerve paralysis following post-traumatic aortic pseudoaneurysm.

    PubMed

    Mesolella, Massimo; Ricciardiello, Filippo; Tafuri, Domenico; Varriale, Roberto; Testa, Domenico

    2016-01-01

    Blunt trauma to the neck or to the chest are increasingly observed in the emergency clinical practice. They usually follow motor vehicle accidents or may be work or sports related. A wide pattern of clinical presentation can be potentially encountered. We report the uncommon case of a patient who was referred to our observation presenting with hoarseness and disphagia. Twenty days before he had sustained a car accident with trauma to the chest, neck and the mandible. Laryngoscopy showed a left recurrent laryngeal nerve palsy. Further otolaryngo-logical examination showed no other abnormality. At CT and MR imaging a post-traumatic aortic pseudoaneurysm was revealed. The aortic pseudoaneurysm was consequently repaired by implantation of an endovascular stent graft under local anesthesia. The patient was discharged 10 days later. At 30-days follow-up laryngoscopy the left vocal cord palsy was completely resolved. Hoarseness associated with a dilated left atrium in a patient with mitral valve stenosis was initially described by Ortner more than a century ago. Since then several non malignant, cardiovascular, intrathoracic disease that results in embarrassment from recurrent laryngeal nerve palsy usually by stretching, pulling or compression; thus, the correlations of these pathologies was termed as cardiovocal syndrome or Ortner's syndrome. The reported case illustrates that life-threatening cardiovascular comorbidities can cause hoarseness and that an impaired recurrent laryngeal nerve might be correctable.

  15. Delayed recurrent nerve paralysis following post-traumatic aortic pseudoaneurysm

    PubMed Central

    Ricciardiello, Filippo; Tafuri, Domenico; Varriale, Roberto; Testa, Domenico

    2016-01-01

    Abstract Blunt trauma to the neck or to the chest are increasingly observed in the emergency clinical practice. They usually follow motor vehicle accidents or may be work or sports related. A wide pattern of clinical presentation can be potentially encountered. We report the uncommon case of a patient who was referred to our observation presenting with hoarseness and disphagia. Twenty days before he had sustained a car accident with trauma to the chest, neck and the mandible. Laryngoscopy showed a left recurrent laryngeal nerve palsy. Further otolaryngo-logical examination showed no other abnormality. At CT and MR imaging a post-traumatic aortic pseudoaneurysm was revealed. The aortic pseudoaneurysm was consequently repaired by implantation of an endovascular stent graft under local anesthesia. The patient was discharged 10 days later. At 30-days follow-up laryngoscopy the left vocal cord palsy was completely resolved. Hoarseness associated with a dilated left atrium in a patient with mitral valve stenosis was initially described by Ortner more than a century ago. Since then several non malignant, cardiovascular, intrathoracic disease that results in embarrassment from recurrent laryngeal nerve palsy usually by stretching, pulling or compression; thus, the correlations of these pathologies was termed as cardiovocal syndrome or Ortner’s syndrome. The reported case illustrates that life-threatening cardiovascular comorbidities can cause hoarseness and that an impaired recurrent laryngeal nerve might be correctable. PMID:28352797

  16. Effect of ammonia on ozone-initiated formation of indoor secondary products with emissions from cleaning products

    NASA Astrophysics Data System (ADS)

    Huang, Yu; Lee, Shun Cheng; Ho, Kin Fai; Ho, Steven Sai Hang; Cao, Nanying; Cheng, Yan; Gao, Yuan

    2012-11-01

    Biogenic volatile organic compounds (BVOCs) emitted from cleaning products and air fresheners indoors are prone to oxidation resulting in the formation of secondary pollutants that can pose health risks on residents. Ammonia (NH3) is ubiquitous in ambient and indoor environments. In this study, we investigated the effect of ammonia (NH3) on secondary pollutants formation from the ozonolysis of BVOCs emitted from cleaning products including floor cleaner (FC), kitchen cleaner (KC) and dishwashing detergent (DD) in a large environmental chamber. Our results demonstrated that the presence of NH3 (maximum concentration is 240 ppb) could significantly enhance secondary organic aerosols (SOAs) formation from the ozonolysis of all the three categories of cleaning products. For example, for the FC sample, the maximum total particle concentration was up to 2.0 × 104 # cm-3 in the presence of NH3, while it was 1.3 × 104 # cm-3 which was 35% lower without NH3. However, it was found that the extent of NH3 effect on SOAs formation from the ozonolysis of BVOCs emissions was component-dependent. The presence of NH3 in the reaction systems could increase the consumptions of d-limonene that is the dominant BVOC species as identified in cleaning products. The percent yields (%) of secondary carbonyl compounds generated from the ozonolysis of BVOCs emitted from three categories of cleaning products were identified in the presence and absence of NH3, respectively. The increase in SOAs particle number concentration can be attributed to the formation of condensable salts from reactions between NH3 and organic compounds generated from the BVOCs ozonolysis processes. By investigating the NH3 effect on the ozonolysis of BVOCs mixtures in contrast to the chemistry of individual compounds, a better assessment can be made of the overall impact cleaning products have on real indoor environments.

  17. Traumatic Pseudoaneurysm of Right Extracranial Internal Carotid Artery: A Rare Entity and Recent Advancement of Treatment with Minimally Invasive Technique

    PubMed Central

    Ong, Joo Lian Julian; Jalaludin, Salmah

    2016-01-01

    The purpose is to describe a case of traumatic right extracranial internal carotid artery (EICA) pseudoaneurysm, which is a rare entity and the evolution of treatment from surgery to minimally invasive intervention by endovascular stenting and coiling. We reported a case of traumatic right EICA pseudoaneurysm who presented with multiple cranial nerve palsies. Multiple radiological examinations [including magnetic resonance imaging (MRI) with angiogram, computed tomography angiogram (CTA), and digital subtraction angiogram (DSA)] demonstrated right EICA pseudoaneurysm. The pseudoaneurysm was successfully treated with endovascular stenting and coiling. EICA pseudoaneurysm is a rare entity, and open surgery was the gold standard of treatment. Current technology allows endovascular stenting and coiling of pseudoaneurysm as an alternative treatment. It is minimally invasive, associated with lesser complications, better recovery and a shorter hospital stay. PMID:27547119

  18. Multidrug Resistant Pseudomonas Mycotic Pseudoaneurysm following Cardiac Transplant Bridged by Ventricular Assistant Device

    PubMed Central

    Williams, M.; Horvath, R.

    2017-01-01

    Mycotic pseudoaneurysm of aorta following cardiac surgery is rare but is highly fatal if it is unrecognized and untreated. Here, we report a case of a 45-year-old male patient who presented with rapidly progressive multiple pseudoaneurysms of the ascending aorta infected with multidrug resistant (MDR) Pseudomonas aeruginosa at 5 weeks after cardiac transplantation, on a background of prior bridging therapy with left ventricular assistant device (LVAD). The patient was successfully treated with the newer cephalosporin, Ceftolozane/Tazobactam, in combination with surgery. This is the first reported case of mycotic pseudoaneurysm infected with MDR Pseudomonas. This case also highlights the importance of high vigilance and timely multimodality treatment in the diagnosis and management of mycotic pseudoaneurysm following cardiac transplant, especially in patients who had LVAD. PMID:28386491

  19. Pseudoaneurysm of the inferior epigastric artery: a rare complication of laparoscopic ventral hernia repair.

    PubMed

    Nichols-Totten, Kysha; Pollema, Travis; Moncure, Michael

    2012-02-01

    Pseudoaneurysm of the inferior epigastric artery (IEA) is a recognized complication of surgery; however, it is a very rare clinical occurrence. The anatomic position of the IEA subjects patients to possible IEA injury during abdominal wall procedures that are close to the artery, such as insertions of drains, Tenckhoff catheters, laparoscopic trocars, or paracentesis. Treatment options include open surgery, percutaneous coil embolization, embolization with N-butyl cyanoacrylate, sonographic-guided thrombin injection, or sonographic-guided compression. We report the first case of a pseudoaneurysm arising from the IEA after a laparoscopic ventral hernia repair. To our knowledge, 17 IEA pseudoaneurysms have been reported, only 3 of which were spontaneous. The pseudoaneurysm in our patient was successfully treated by percutaneous injection of thrombin by interventional radiology.

  20. Damage control surgery in patient with delayed rupture of pseudoaneurysm after blunt abdominal trauma

    PubMed Central

    Park, Chan Yong; Ju, Jae Kyun

    2012-01-01

    Delayed rupture of post-traumatic pseudoaneurysms of the visceral arteries, especially the pancreaticoduodenal artery, is uncommon. Here, we describe a 55-year-old man hemorrhaging from a pseudoaneurysm of the inferior pancreaticoduodenal artery (IPDA). Computed tomography of the abdomen showed active bleeding in the IPDA and large amounts of hemoperitoneum and hemoretroperitoneum. Selective mesenteric angiography showed that the pseudoaneurysm arose from the IPDA, and treatment by angioembolization failed because the involved artery was too tortuous to fit with a catheter. Damage control surgery with surgical ligation and pad packing was successfully performed. The patient had an uncomplicated postoperative course and was discharged 19 days after the operation. To our knowledge, this is the first report of ruptured pseudoaneurysm of an IPDA after blunt abdominal trauma from Korea. PMID:22880189

  1. Damage control surgery in patient with delayed rupture of pseudoaneurysm after blunt abdominal trauma.

    PubMed

    Park, Chan Yong; Ju, Jae Kyun; Kim, Jung Chul

    2012-08-01

    Delayed rupture of post-traumatic pseudoaneurysms of the visceral arteries, especially the pancreaticoduodenal artery, is uncommon. Here, we describe a 55-year-old man hemorrhaging from a pseudoaneurysm of the inferior pancreaticoduodenal artery (IPDA). Computed tomography of the abdomen showed active bleeding in the IPDA and large amounts of hemoperitoneum and hemoretroperitoneum. Selective mesenteric angiography showed that the pseudoaneurysm arose from the IPDA, and treatment by angioembolization failed because the involved artery was too tortuous to fit with a catheter. Damage control surgery with surgical ligation and pad packing was successfully performed. The patient had an uncomplicated postoperative course and was discharged 19 days after the operation. To our knowledge, this is the first report of ruptured pseudoaneurysm of an IPDA after blunt abdominal trauma from Korea.

  2. Pipeline embolization device as primary treatment for cervical internal carotid artery pseudoaneurysms

    PubMed Central

    Wang, Arthur; Santarelli, Justin; Stiefel, Michael F.

    2017-01-01

    Background: Limited data exists on the durability and occlusion rate of treating extracranial cervical internal carotid artery pseudoaneurysms using the pipeline embolization device (PED) flow-diverting stent. Methods: Three patients presenting with dissecting cervical internal carotid artery pseudoaneurysms were treated with the PED as the sole treatment modality. Results: In all three patients, successful aneurysmal occlusion and parent vessel reconstruction occurred on immediate angiography and continued on 6-month follow-up. No immediate or delayed complications were seen, and all patients remained neurologically intact. Conclusion: Complete aneurysmal occlusion and long-term angiographic occlusion can occur after PED treatment of cervical carotid pseudoaneurysms. In select patients, the PED can be a suitable primary treatment modality with good neurological outcome for cervical carotid pseudoaneurysms. PMID:28217382

  3. Pseudoaneurysm After Spontaneous Rupture of Renal Angiomyolipoma in Tuberous Sclerosis: Successful Treatment with Percutaneous Thrombin Injection

    SciTech Connect

    Corso, Rocco Carrafiello, Gianpaolo; Rampoldi, Antonio; Leni, Davide; Ticca, Cristiana; Vercelli, Ruggero; Vanzulli, Angelo

    2005-04-15

    We report a case of a large perinephric pseudoaneurysm due to spontaneous rupture of renal angiomyolipoma, occluded by percutaneous thrombin injection under ultrasound guidance in a young woman affected by tuberous sclerosis.

  4. Formation of secondary phase at grain boundary of flash-sintered BaTiO3.

    PubMed

    Uehashi, Akinori; Sasaki, Katsuhiro; Tokunaga, Tomoharu; Yoshida, Hidehiro; Yamamoto, Takahisa

    2014-11-01

    decrease with an increase in electric fields, which is very different from the case of ZrO2-3mol%Y2O3 and Y2O3 ceramics. This fact means that application of high electric fields does not effectively operate for enhancement of shrinkage rates in the case of BaTiO3. In contrast, only gradual current increment was observed at 25V/cm, which is categorized in field-assisted sintering (FAST) process. The density of the green compact at 25V/cm was more than 95%.To investigate the mechanism of the decrease in a total shrinkage with electric fields, the microstructure of flash-sintered compact was observed. As a result, it was found that discharge occurs during flash-sintering process, indicating that the input power due to high electric fields does not work effectively. A typical example of the microstructure near the discharge area is shown in Fig. 1. Fig. 1 is a TEM bright field image taken from BaTiO3 flash-sintered at 100V/cm. As seen in the image, the formation of a secondary phase along the grain boundary can be clearly seen. Diffractometric and EDS analysis have revealed that the secondary phase is BaTi4O9, one of compounds between BaO and TiO2 system. By discharging, grain boundaries partially melt and a part of Ba vaporizes to form BaTi4O9 with cooling. To investigate flash-sintering behaviors, it was concluded that FAST process play an important role to enhance the shrinklage rate in the case of BaTiO3.jmicro;63/suppl_1/i19/DFU048F1F1DFU048F1Fig. 1.TEM bright field image of a secondary phase and the electron diffraction pattern taken from the secondary phase.

  5. External carotid artery pseudoaneurysm with arteriovenous fistula: A rare complication of glass shrapnel injury

    PubMed Central

    Saraf, Rashmi; Sharma, Rajaram; Jaini, Lodha V; Mhashal, Shashikant

    2016-01-01

    Posttraumatic external carotid artery pseudoaneurysm with arteriovenous fistula is a rare condition. An 8-year-old child presented with painful pulsatile swelling in the preauricular region following a penetrating glass shrapnel injury. Detailed evaluation showed distal external carotid artery pseudoaneurysm with fistula, which was draining into the retromandibular vein. Endovascular treatment was performed. This case highlights the role of endovascular intervention for such rare complicated vascular pathologies. PMID:28104948

  6. Uncommon cause of left ventricular pseudoaneurysm: case report and review of literature.

    PubMed

    Wei, Wu; Hui, Chen; Sheng-Yu, Wang; Xin, Diao

    2014-06-01

    We report a case of an 18-year-old man without tuberculosis history who presented with chest distress, dyspnea, and fever. Chest computed tomography scan and echocardiography showed left ventricular posterior wall pseudoaneurysm and perforation. Unfortunately, the patient died shortly after surgery. On the basis of surgical pathology, we made a final diagnosis of tuberculous pericarditis complicated with left ventricular pseudoaneurysm. This has not been reported before in the published literature.

  7. Stent-Graft Repair of a Large Cervical Internal Carotid Artery Pseudoaneurysm Causing Dysphagia

    SciTech Connect

    Gupta, Vivek Niranjan, Khandelwal; Rawat, Lokesh; Gupta, A. K.

    2009-05-15

    Pseudoaneurysms of the cervical internal carotid artery (ICA) are rare and most frequently result from trauma, infection, or sometimes spontaneously. They have the potential to cause life-threatening hemorrhage; thus, their immediate management is necessary. Endovascular treatment by stent graft placement in the affected artery appears to be a safe and effective treatment option. We present a case of a child who presented with neck swelling and dysphagia caused by a ruptured cervical ICA pseudoaneurysm which was managed by stent graft placement.

  8. Embolisation of a leaking pseudoaneurysm of the main artery supplying a replanted arm: a case report.

    PubMed

    Tan, J J; Low, C K

    1999-07-01

    A 51-year-old patient suffered a near amputation of the right arm. Replant of the arm was performed and the brachial artery was grafted with a vein. A week later, there was severe bleeding from a leaking pseudoaneurysm at the proximal junction of the grafted artery. This was managed with embolization using coils and resulted in successful obliteration of the pseudoaneurysm without necrosis of the replanted arm.

  9. Percutaneous Cyanoacrylate Glue Injection into the Renal Pseudoaneurysm to Control Intractable Hematuria After Percutaneous Nephrolithotomy

    SciTech Connect

    Lal, Anupam Kumar, Ajay; Prakash, Mahesh; Singhal, Manphool; Agarwal, Mayank Mohan; Sarkar, Debansu; Khandelwal, Niranjan

    2009-07-15

    We report a case of a 43-year-old man who developed intractable hematuria after percutaneous nephrolithotomy. Angiography detected a pseudoaneurysm arising from the lower polar artery; however, embolization could not be performed because of unfavorable vascular anatomy. A percutaneous thrombin injection under ultrasound guidance initially controlled the bleeding, but hematuria subsequently recurred as a result of recanalization of the aneurysm. The case was successfully managed with ultrasound- and fluoroscopic-guided direct injection of cyanoacrylate glue into the pseudoaneurysm.

  10. Traumatic Inferior Gluteal Artery Pseudoaneurysm and Arteriovenous Fistula Managed with Emergency Transcatheter Embolization

    SciTech Connect

    Keeling, A. N.; Naughton, P. A.; Leahy, A. L.; Lee, M. J.

    2008-07-15

    We present a case of blunt trauma to the buttock resulting in an inferior gluteal artery pseudoaneurysm and arteriovenous fistula. The characteristic diagnostic features on CT angiography and digital subtraction angiography (DSA), along with the emergency percutaneous management of this traumatic vascular injury, are described. A review of the literature demonstrates inferior gluteal artery pseudoaneurysm is a rare condition, while successful treatment with glue embolization is previously unreported.

  11. Percutaneous cyanoacrylate glue injection into the renal pseudoaneurysm to control intractable hematuria after percutaneous nephrolithotomy.

    PubMed

    Lal, Anupam; Kumar, Ajay; Prakash, Mahesh; Singhal, Manphool; Agarwal, Mayank Mohan; Sarkar, Debansu; Khandelwal, Niranjan

    2009-07-01

    We report a case of a 43-year-old man who developed intractable hematuria after percutaneous nephrolithotomy. Angiography detected a pseudoaneurysm arising from the lower polar artery; however, embolization could not be performed because of unfavorable vascular anatomy. A percutaneous thrombin injection under ultrasound guidance initially controlled the bleeding, but hematuria subsequently recurred as a result of recanalization of the aneurysm. The case was successfully managed with ultrasound- and fluoroscopic-guided direct injection of cyanoacrylate glue into the pseudoaneurysm.

  12. Minimally Invasive Therapy of Pseudoaneurysms of the Trunk: Application of Thrombin

    SciTech Connect

    Schellhammer, Frank Steinhaus, Daniele; Cohnen, Mathias; Hoppe, Jonas; Moedder, Ulrich; Fuerst, Guenter

    2008-05-15

    Thrombin injection has been proven to be successful in postcatheterization pseudoaneurysms. However, there are only a few reports on the treatment of pseudoaneurysms of the trunk. We report our first experiences using a percutaneous as well as an endovascular access. Eight iatrogenic pseudoaneurysms of the trunk (aorta, n = 4; pulmonary artery, n = 1; gastroduodenal artery, n = 1; left gastric artery, n = 1, renal artery, n = 1) were treated either percutaneously using CT guidance (n = 3) or via an endovascular access (n = 5). Noninvasive control angiograms were performed at day 1 and weeks 1 and 3 by either CT or MR angiography. The total volume of the pseudoaneurysms was 31.2 {+-} 23.1 ml on average, with a mean volume of the perfused aneurysmal lumen of 12.9 {+-} 7.2 ml. The maximum diameter was 4.1 {+-} 1.39 cm on average. In each case, the aneurysmal neck was not wider than 2 mm. One pseudoaneurysm occluded spontaneously following selective catheterization. The remaining pseudoaneurysms were successfully treated by injection of 765 {+-} 438.1 IU thrombin. In one individual, a nontarget embolization occurred, as well as an intervention-associated rupture of a pseudoaneurysm. High-grade stenoses of the donor artery were found in a different case. Only once was the endoluminal access converted to a percutaneous one. Thrombin injection might be a future first-line treatment of vascular lesions such as pseudoaneurysms of the trunk. In our experience both percutanous and endoluminal access are technically feasible and safe. However, further experiences are mandatory, especially concerning the question of dosage and long-term results.

  13. Transarterial Thrombin Injection Secured with an Embolic Protection Device as a Treatment for a Superior Mesenteric Artery Pseudoaneurysm

    SciTech Connect

    Juszkat, Robert Krasinski, Zbigniew; Wykretowicz, Mateusz; Staniszewski, Ryszard; Majewski, Waclaw

    2011-02-15

    A pseudoaneurysm of the superior mesenteric artery (SMA) is a rare and life-threatening condition of various etiology. Even unruptured it can cause severe health problems or death. We report a 71-year-old male with a SMA pseudoaneurysm who was successfully treated with a transarterial thrombin injection secured with an embolic protection device used in carotid angioplasty. To our knowledge, this is the first case of a SMA pseudoaneurysm treated by this method.

  14. Streptomycetes in micro-cultures: growth, production of secondary metabolites, and storage and retrieval in the 96-well format.

    PubMed

    Minas, W; Bailey, J E; Duetz, W

    2000-12-01

    Mycelium-forming Streptomyces strains were grown in one milliliter liquid micro-cultures in square deep-well microtiter plates. Growth was evaluated with respect to biomass formation and production of secondary metabolites which were found to be very similar in the micro-cultures, bioreactor, and shake flask cultivations, respectively. Despite repetitive sampling and extensive growth on the walls of the wells, no cross contamination occurred. Furthermore, we successfully employed cold storage at -20 degrees C of spore suspensions (in the 96-well format), directly prepared from cultures grown on agar in the microtitre plate. Cultures were retrieved by replicating aliquots from the frozen spore suspensions.

  15. Laparoscopic management of a cystic artery pseudoaneurysm in a patient with calculus cholecystitis

    PubMed Central

    Loizides, Sofronis; Ali, Asad; Newton, Richard; Singh, Krishna Kumar

    2015-01-01

    INTRODUCTION Pseudoaneurysm of the cystic artery is very rare. In the majority of cases it has been reported as a post-operative complication of laparoscopic cholecystectomy, however it has also been associated with the presence of acute cholecystitis or pancreatitis. When these pseudoaneurysms rupture they can lead to intraperitoneal bleeding, haemobilia and upper gastrointestinal haemorrhage. Radiological as well as open surgical approaches have been described for control of this rare pathology. PRESENTATION OF CASE We report the laparoscopic surgical management of an incidental, unruptured cystic artery pseudoaneurysm in a patient presenting with acute cholecystitis. DISCUSSION Cystic artery pseudoaneurysm is a rare entity and as such there is no consensus on the clinical management of this condition. A variety of treatment strategies have been reported in the literature including radiological selective embolisation and coiling, open cholecystectomy with ligation of the aneurysm, or a two-step approach involving radiological management of the pseudoaneurysm followed by an elective cholecystectomy. CONCLUSION In this report we have demonstrated that laparoscopic management of a cystic artery pseudoaneurysm with simultaneous laparoscopic cholecystectomy is feasible and safe. This avoids multiple invasive procedures and decreases morbidity associated with open surgery. PMID:26291047

  16. Formation of anthropogenic secondary organic aerosol (SOA) and its influence on biogenic SOA properties

    NASA Astrophysics Data System (ADS)

    Emanuelsson, E. U.; Hallquist, M.; Kristensen, K.; Glasius, M.; Bohn, B.; Fuchs, H.; Kammer, B.; Kiendler-Scharr, A.; Nehr, S.; Rubach, F.; Tillmann, R.; Wahner, A.; Wu, H.-C.; Mentel, Th. F.

    2012-08-01

    Secondary organic aerosol (SOA) formation from mixed anthropogenic and biogenic precursors has been studied exposing reaction mixtures to natural sunlight in the SAPHIR chamber in Jülich, Germany. Several experiments with exclusively anthropogenic precursors were performed to establish a relationship between yield and organic aerosol mass loading for the atmospheric relevant range of aerosol loads of 0.01 to 10 μg m-3. The yields (0.5-9%) were comparable to previous data and further used for the detailed evaluation of the mixed biogenic and anthropogenic experiments. For the mixed experiments a number of different oxidation schemes were addressed. The reactivity, the sequence of addition, and the amount of the precursors influenced the SOA properties. Monoterpene oxidation products, including carboxylic acids and dimer esters were identified in the aged aerosol at levels comparable to ambient air. OH radicals were measured by Laser Induced Fluorescence, which allowed for establishing relations of aerosol properties and composition to the experimental OH dose. Furthermore, the OH measurements in combination with the derived yields for anthropogenic SOA enabled application of a simplified model to calculate the chemical turnover of the anthropogenic precursor and corresponding anthropogenic contribution to the mixed aerosol. The estimated anthropogenic contributions were ranging from small (≈8%) up to significant fraction (>50%) providing a suitable range to study the effect of aerosol composition on the aerosol volatility (volume fraction remaining at 343 K: 0.86-0.94). The anthropogenic aerosol had higher oxygen to carbon ratio O/C and was less volatile than the biogenic fraction. However, in order to produce significant amount of anthropogenic SOA the reaction mixtures needed a higher OH dose that also increased O/C and provided a less volatile aerosol. A strong positive correlation was found between changes in volatility and O/C with the exception during dark

  17. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: chemical characterization of the products

    NASA Astrophysics Data System (ADS)

    Grgić, Irena; Kitanovski, Zoran; Kroflič, Ana; Čusak, Alen

    2014-05-01

    One of the largest primary sources of organic aerosol in the atmosphere is biomass burning (BB) (Laskin et al. 2009); in Europe its contribution to annual mean of PM10 is between 3 and 14 % (Maenhaut et al. 2012). During the process of wood burning many different products are formed via thermal degradation of wood lignin. Hardwood burning produces mainly syringol (2,6-dimetoxyphenol) derivatives, while softwood burning exclusively guaiacol (2-methoxyphenol) and its derivatives. Taking into account physical properties of methoxyphenols only, their concentrations in atmospheric waters might be underestimated. So, their aqueous phase reactions can be an additional source of SOA, especially in regions under significant influence of wood combustion. An important class of compounds formed during physical and chemical aging of the primary BBA in the atmosphere is nitrocatechols, known as strong absorbers of UV and Vis light (Claeys et al. 2012). Very recently, methyl-nitrocatechols were proposed as suitable markers for highly oxidized secondary BBA (Iinuma et al. 2010, Kitanovski et al. 2012). In the present work, the formation of SOA through aqueous phase photooxidation and nitration of guaiacol was examined. The key objective was to chemically characterize the main low-volatility products and further to check their possible presence in the urban atmospheric aerosols. The aqueous phase reactions were performed in a thermostated reactor under simulated sunlight in the presence of H2O2 and nitrite. Guaiacol reaction products were first concentrated by solid-phase extraction (SPE) and then subjected to semi-preparative liquid chromatography.The main product compounds were fractionated and isolated as pure solids and their structure was further elucidated by using nuclear magnetic resonance spectroscopy (1H, 13C and 2D NMR) and direct infusion negative ion electro-spray ionization tandem mass spectrometry (( )ESI-MS/MS). The main photonitration products of guaiacol (4

  18. The dual functions of WLIM1a in cell elongation and secondary wall formation in developing cotton fibers.

    PubMed

    Han, Li-Bo; Li, Yuan-Bao; Wang, Hai-Yun; Wu, Xiao-Min; Li, Chun-Li; Luo, Ming; Wu, Shen-Jie; Kong, Zhao-Sheng; Pei, Yan; Jiao, Gai-Li; Xia, Gui-Xian

    2013-11-01

    LIN-11, Isl1 and MEC-3 (LIM)-domain proteins play pivotal roles in a variety of cellular processes in animals, but plant LIM functions remain largely unexplored. Here, we demonstrate dual roles of the WLIM1a gene in fiber development in upland cotton (Gossypium hirsutum). WLIM1a is preferentially expressed during the elongation and secondary wall synthesis stages in developing fibers. Overexpression of WLIM1a in cotton led to significant changes in fiber length and secondary wall structure. Compared with the wild type, fibers of WLIM1a-overexpressing plants grew longer and formed a thinner and more compact secondary cell wall, which contributed to improved fiber strength and fineness. Functional studies demonstrated that (1) WLIM1a acts as an actin bundler to facilitate elongation of fiber cells and (2) WLIM1a also functions as a transcription factor to activate expression of Phe ammonia lyase-box genes involved in phenylpropanoid biosynthesis to build up the secondary cell wall. WLIM1a localizes in the cytosol and nucleus and moves into the nucleus in response to hydrogen peroxide. Taken together, these results demonstrate that WLIM1a has dual roles in cotton fiber development, elongation, and secondary wall formation. Moreover, our study shows that lignin/lignin-like phenolics may substantially affect cotton fiber quality; this finding may guide cotton breeding for improved fiber traits.

  19. Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

    EPA Science Inventory

    Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemic...

  20. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    EPA Science Inventory

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  1. Superior Mesenteric Artery Stent-graft Placement in a Patient with Pseudoaneurysm Developing from a Pancreatic Pseudocyst

    SciTech Connect

    Ogino, H.; Banno, T.; Sato, Y.; Hara, M.; Shibamoto, Y.

    2004-01-15

    Pseudoaneurysm is a relatively rare but serious complication of pancreatitis which is often fatal. We report successful stent-graft placement in the superior mesenteric artery in a 45-year-old man with a pancreatic pseudocyst that grew during therapy for chronic pancreatitis and developed into a pseudoaneurysm. After a stent graft was inserted in the superior mesenteric artery, the pseudoaneurysm disappeared and no further complications developed. Stent-graft placement was considered to be a useful therapy for pseudoaneurysms in the superior mesenteric arterial region.

  2. Post-traumatic pseudoaneurysm of the medial plantar artery combined with tarsal tunnel syndrome: two case reports.

    PubMed

    Park, Sang-Eun; Kim, Ji-Chang; Ji, Jong-Hun; Kim, Young-Yul; Lee, Hwan-Hee; Jeong, Jae-Jung

    2013-03-01

    Pseudoaneurysms in the foot are more often reported in the lateral plantar artery than the medial plantar artery, most likely because of its more superficial location. There are no reports of pseudoaneurysm of the medial plantar artery after trauma. We present two cases of pseudoaneurysm of the medial plantar artery after blunt foot trauma and foot laceration. This pseudoaneurysm compressed a posterior tibial nerve, resulting in tarsal tunnel syndrome. The patients were treated successfully using transcatheter embolization without the need for surgical intervention. The tarsal tunnel syndrome also subsided. Here, the authors report these cases and provide a review of literature.

  3. Thrombin Injection for Treatment of Brachial Artery Pseudoaneurysm at the Site of a Hemodialysis Fistula: Report of Two Patients

    SciTech Connect

    Clark, Timothy W.I.; Abraham, Robert J.

    2000-09-15

    We report two patients with arteriovenous hemodialysis fistulas that were complicated by brachial artery pseudoaneurysms. Each pseudoanerysm was percutaneously thrombosed with an injection of thrombin, using techniques to prevent escape of thrombin into the native brachial artery. In one patient, an angioplasty balloon was inflated across the neck of the aneurysm during thrombin injection. In the second patient, thrombin was injected during ultrasound-guided compression of the neck of the pseudoaneurysm. Complete thrombosis of each pseudoaneurysm was achieved within 30 sec. No ischemic or embolic events occurred. This technique may be useful in treating pseudoaneurysms of smaller peripheral arteries.

  4. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: a kinetic study

    NASA Astrophysics Data System (ADS)

    Kroflič, Ana; Grgić, Irena

    2014-05-01

    It is well known that atmospheric aerosols play a crucial role in the Earth's climate and public health (Pöschl 2005). Despite a great effort invested in the studies of secondary organic aerosol (SOA) budget, composition, and its formation mechanisms, there is still a gap between field observations and atmospheric model predictions (Heald et al. 2005, Hallquist et al. 2009, and Lim et al. 2010). The insisting uncertainties surrounding SOA formation and aging thus gained an increasing interest in atmospheric aqueous phase chemistry; they call for more complex and time consuming studies at the environmentally relevant conditions allowing confident extrapolation to desired ambient conditions. In addition to the adverse health effects of atmospheric particulate matter (PM) as such, toxicity is also attributed to nitro-aromatic and other organic compounds which have already been detected in real aerosol samples (Traversi et al. 2009). Moreover, low-volatility aromatic derivatives are believed to form at least partly in the aerosol aqueous phase and not only in the gas phase from where they partition into water droplets (Ervens et al. 2011). Two nitro derivatives of biomass burning tracer guaiacol have recently been found in winter PM10 samples from the city of Ljubljana, Slovenia, and aqueous photonitration reaction was proposed as their possible production pathway (Kitanovski et al. 2012). In this study the kinetics of guaiacol nitration in aqueous solution was investigated in the presence of H2O2 and NO2¯ upon simulated solar irradiation (Xenon lamp, 300 W). During the experiment the DURAN® flask with the reaction mixture was held in the thermostated bath and thoroughly mixed. The reaction was monitored for 44 hours at different temperatures. Guaiacol and its main nitro-products (4-nitroguaiacol, 4-NG; 6-nitroguaiacol, 6-NG; and 4,6-dinitroguaiacol, 4,6-DNG) were quantified in every aliquot, taken from the reaction mixture, by use of high pressure liquid

  5. Organic photolysis reactions in tropospheric aerosols: effect on secondary organic aerosol formation and lifetime

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Madronich, S.; Kasibhatla, P. S.; Tyndall, G.; Aumont, B.; Jimenez, J. L.; Lee-Taylor, J.; Orlando, J.

    2015-08-01

    This study presents the first modeling estimates of the potential effect of gas- and particle-phase organic photolysis reactions on the formation and lifetime of secondary organic aerosols (SOAs). Typically only photolysis of smaller organic molecules (e.g., formaldehyde) for which explicit data exist is included in chemistry-climate models. Here, we specifically examine the photolysis of larger molecules that actively partition between the gas and particle phases. The chemical mechanism generator GECKO-A is used to explicitly model SOA formation from α-pinene, toluene, and C12 and C16 n-alkane reactions with OH at low and high NOx. Simulations are conducted for typical mid-latitude conditions and a solar zenith angle of 45° (permanent daylight). The results show that after 4 days of chemical aging under those conditions (equivalent to 8 days in the summer mid-latitudes), gas-phase photolysis leads to a moderate decrease in SOA yields, i.e., ~15 % (low NOx) to ~45 % (high NOx) for α-pinene, ~15 % for toluene, ~25 % for C12 n-alkane, and ~10 % for C16 n-alkane. The small effect of gas-phase photolysis on low-volatility n-alkanes such as C16 n-alkane is due to the rapid partitioning of early-generation products to the particle phase, where they are protected from gas-phase photolysis. Minor changes are found in the volatility distribution of organic products and in oxygen to carbon ratios. The decrease in SOA mass is increasingly more important after a day of chemical processing, suggesting that most laboratory experiments are likely too short to quantify the effect of gas-phase photolysis on SOA yields. Our results also suggest that many molecules containing chromophores are preferentially partitioned into the particle phase before they can be photolyzed in the gas phase. Given the growing experimental evidence that these molecules can undergo in-particle photolysis, we performed sensitivity simulations using an empirically estimated SOA photolysis rate of JSOA

  6. Organic photolysis reactions in tropospheric aerosols: effect on secondary organic aerosol formation and lifetime

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Madronich, S.; Kasibhatla, P. S.; Tyndall, G.; Aumont, B.; Jimenez, J. L.; Lee-Taylor, J.; Orlando, J.

    2015-03-01

    This study presents the first modeling estimates of the potential effect of gas- and particle-phase organic photolysis reactions on the formation and lifetime of secondary organic aerosols (SOA). Typically only photolysis of smaller organic molecules (e.g. formaldehyde) for which explicit data exist is included in chemistry-climate models. Here, we specifically examine the photolysis of larger molecules that actively partition between the gas and particle phases. The chemical mechanism generator GECKO-A is used to explicitly model SOA formation from α-pinene, toluene, and C12 and C16 n-alkane reactions with OH at low- and high-NOx. Simulations are conducted for typical mid-latitude conditions and a solar zenith angle of 45° (permanent daylight). The results show that after four days of chemical aging under those conditions (equivalent to eight days in the summer mid-latitudes), gas-phase photolysis leads to a moderate decrease in SOA yields i.e ~15% (low-NOx) to ~45% (high-NOx) for α-pinene, ~15% for toluene, ~25% for C12-alkane, and ~10% for C16-alkane. The small effect on low volatility n-alkanes such as C16-alkane is due to the rapid partitioning of early-generation products to the particle phase where they are assumed to be protected from gas-phase photolysis. Minor changes are found in the volatility distribution of organic products and in oxygen to carbon ratios. The decrease in SOA mass seems increasingly more important after a day of chemical processing, suggesting that most laboratory experiments are likely too short to quantify the effect of gas-phase photolysis on SOA yields. Our results also suggest that many molecules containing chromophores are preferentially partitioned into the particle phase before they can be photolyzed in the gas-phase. Given the growing experimental evidence that these molecules can undergo in-particle photolysis, we performed sensitivity simulations using an estimated SOA photolysis rate of JSOA=4 x 10-4JNO2. Modeling

  7. Formation of Polychlorinated Biphenyls on Secondary Copper Production Fly Ash: Mechanistic Aspects and Correlation to Other Persistent Organic Pollutants

    PubMed Central

    Jiang, Xiaoxu; Liu, Guorui; Wang, Mei; Zheng, Minghui

    2015-01-01

    Emission of unintentionally formed polychlorinated biphenyls (PCBs) from industrial thermal processes is a global issue. Because the production and use of technical PCB mixtures has been banned, industrial thermal processes have become increasingly important sources of PCBs. Among these processes, secondary copper smelting is an important PCB source in China. In the present study, the potential for fly ash-mediated formation of PCBs in the secondary copper industry, and the mechanisms involved, were studied in laboratory thermochemical experiments. The total PCB concentrations were 37–70 times higher than the initial concentrations. Thermochemical reactions on the fly ash amplified the potential toxic equivalents of PCBs. The formation of PCBs over time and the effect of temperature were investigated. Based on analyses of PCB homologue profiles with different reaction conditions, a chlorination mechanism was proposed for forming PCBs in addition to a de novo synthesis mechanism. The chlorination pathway was supported by close correlations between each pair of adjacent homologue groups. Formation of PCBs and multiple persistent organic pollutants, including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated naphthalenes, occurred during the tests, indicating that these compounds may share similar formation mechanisms. PMID:26374495

  8. Formation of Polychlorinated Biphenyls on Secondary Copper Production Fly Ash: Mechanistic Aspects and Correlation to Other Persistent Organic Pollutants

    NASA Astrophysics Data System (ADS)

    Jiang, Xiaoxu; Liu, Guorui; Wang, Mei; Zheng, Minghui

    2015-09-01

    Emission of unintentionally formed polychlorinated biphenyls (PCBs) from industrial thermal processes is a global issue. Because the production and use of technical PCB mixtures has been banned, industrial thermal processes have become increasingly important sources of PCBs. Among these processes, secondary copper smelting is an important PCB source in China. In the present study, the potential for fly ash-mediated formation of PCBs in the secondary copper industry, and the mechanisms involved, were studied in laboratory thermochemical experiments. The total PCB concentrations were 37-70 times higher than the initial concentrations. Thermochemical reactions on the fly ash amplified the potential toxic equivalents of PCBs. The formation of PCBs over time and the effect of temperature were investigated. Based on analyses of PCB homologue profiles with different reaction conditions, a chlorination mechanism was proposed for forming PCBs in addition to a de novo synthesis mechanism. The chlorination pathway was supported by close correlations between each pair of adjacent homologue groups. Formation of PCBs and multiple persistent organic pollutants, including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated naphthalenes, occurred during the tests, indicating that these compounds may share similar formation mechanisms.

  9. Development of anterior inferior cerebellar artery pseudoaneurysm after gamma knife surgery for vestibular schwannoma. A case report and review of the literature.

    PubMed

    Sunderland, Geraint; Hassan, Faizul; Bhatnagar, Priya; Mitchell, Patrick; Jayakrishnan, Vijayam; Forster, David; Mendelow, Alexander David

    2014-08-01

    Gamma knife surgery (GKS) is a well-established modality for controlling the progression of vestibular schwannomas. Adverse effects of this treatment are extremely rare but include cyst formation and malignant transformation. We report a case of anterior inferior cerebellar artery (AICA) pseudoaneurysm development rupture presenting as a poor WFNS grade subarachnoid haemorrhage. This is only the fourth case of aneurysm development (AICA aneurysm) following GKS reported but due to its serious nature we believe this potential complication warrants awareness in those offering this treatment.

  10. Iatrogenic pseudoaneurysm of the popliteal artery following corrective tibial osteotomy.

    PubMed

    Szyber, P; Skóra, J; Rybak, W; Pupka, A

    2011-09-01

    Due to its anatomical location the popliteal artery is exposed to injury during surgical procedures in the region of the knee joint, in particular during high-level corrective osteotomies of the proximal tibial epiphysis. Nevertheless, posttraumatic (iatrogenic) pseudoaneurysm constitutes a very rare complication of the procedure. Only few reports of such complication have been published and they were usually connected with lateral tibial osteotomy - the accidents after medial osteotomy are seldom. The complication we report was observed in a 52-year-old female patient after corrective osteotomy of the medial portion of the proximal tibial epiphysis. The complication was diagnosed 7 days after surgery on US-examination and subsequently confirmed by emergently performed angio-CT. The patient was referred for urgent reconstructive surgery. No significant complications were observed, neither postoperatively nor during follow-up visits.

  11. Formation of anthropogenic secondary organic aerosol (SOA) and its influence on biogenic SOA properties

    NASA Astrophysics Data System (ADS)

    Emanuelsson, E. U.; Hallquist, M.; Kristensen, K.; Glasius, M.; Bohn, B.; Fuchs, H.; Kammer, B.; Kiendler-Scharr, A.; Nehr, S.; Rubach, F.; Tillmann, R.; Wahner, A.; Wu, H.-C.; Mentel, Th. F.

    2013-03-01

    Secondary organic aerosol (SOA) formation from mixed anthropogenic and biogenic precursors has been studied exposing reaction mixtures to natural sunlight in the SAPHIR chamber in Jülich, Germany. In this study aromatic compounds served as examples of anthropogenic volatile organic compound (VOC) and a mixture of α-pinene and limonene as an example for biogenic VOC. Several experiments with exclusively aromatic precursors were performed to establish a relationship between yield and organic aerosol mass loading for the atmospheric relevant range of aerosol loads of 0.01 to 10 μg m-3. The yields (0.5 to 9%) were comparable to previous data and further used for the detailed evaluation of the mixed biogenic and anthropogenic experiments. For the mixed experiments a number of different oxidation schemes were addressed. The reactivity, the sequence of addition, and the amount of the precursors influenced the SOA properties. Monoterpene oxidation products, including carboxylic acids and dimer esters were identified in the aged aerosol at levels comparable to ambient air. OH radicals were measured by Laser Induced Fluorescence, which allowed for establishing relations of aerosol properties and composition to the experimental OH dose. Furthermore, the OH measurements in combination with the derived yields for aromatic SOA enabled application of a simplified model to calculate the chemical turnover of the aromatic precursor and corresponding anthropogenic contribution to the mixed aerosol. The estimated anthropogenic contributions were ranging from small (≈8%) up to significant fraction (>50%) providing a suitable range to study the effect of aerosol composition on the aerosol volatility (volume fraction remaining (VFR) at 343 K: 0.86-0.94). The aromatic aerosol had higher oxygen to carbon ratio O/C and was less volatile than the biogenic fraction. However, in order to produce significant amount of aromatic SOA the reaction mixtures needed a higher OH dose that also

  12. Septic Shock of Unknown Origin: A Case Report of a Pseudoaneurysm of the Mitral-Aortic Intervalvular Fibrosa

    PubMed Central

    Gil, Julio; Antunes, Hugo; Marmelo, Bruno; Abreu, Luis; Goncalves, Maria Luisa; dos Santos, Luis Ferreira; Cabral, Jose Costa

    2017-01-01

    Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (P-MAIVF) is a rare complication of infective endocarditis and trauma, particularly of aortic valve surgery. Clinical symptoms are usually unspecific and generally due to complications. Transesophageal echocardiography (TEE) is the most commonly used exam to diagnose P-MAIVF. The main echocardiographic feature is the presence of a cavity communicating with the left ventricular outflow tract that expands during systole and collapses during diastole. Most frequent complications are formation of a fistulous tract and compression of adjacent structures. Surgical correction is usually the treatment of choice. The authors describe a case of a female patient with a septic shock of unclear origin. After antibiotic therapy and organ-supporting measures without apparent improvements, a TEE revealed infective endocarditis, complicated with P-MAIVF. Despite adequate treatment, the patient did not survive for long enough to be submitted to surgical repair. PMID:28179972

  13. Modeling the relative contributions of secondary ice formation processes to ice crystal number concentrations within mixed-phase clouds

    NASA Astrophysics Data System (ADS)

    Sullivan, Sylvia; Hoose, Corinna; Nenes, Athanasios

    2016-04-01

    Measurements of in-cloud ice crystal number concentrations can be three or four orders of magnitude greater than the in-cloud ice nuclei number concentrations. This discrepancy can be explained by various secondary ice formation processes, which occur after initial ice nucleation, but the relative importance of these processes, and even the exact physics of each, is still unclear. A simple bin microphysics model (2IM) is constructed to investigate these knowledge gaps. 2IM extends the time-lag collision parameterization of Yano and Phillips, 2011 to include rime splintering, ice-ice aggregation, and droplet shattering and to incorporate the aspect ratio evolution as in Jensen and Harrington, 2015. The relative contribution of the secondary processes under various conditions are shown. In particular, temperature-dependent efficiencies are adjusted for ice-ice aggregation versus collision around -15°C, when rime splintering is no longer active, and the effect of aspect ratio on the process weighting is explored. The resulting simulations are intended to guide secondary ice formation parameterizations in larger-scale mixed-phase cloud schemes.

  14. Enhanced N-nitrosamine formation in pool water by UV irradiation of chlorinated secondary amines in the presence of monochloramine.

    PubMed

    Soltermann, Fabian; Lee, Minju; Canonica, Silvio; von Gunten, Urs

    2013-01-01

    N-Nitrosamines, in particular N-nitrosodimethylamine (NDMA), are carcinogens, which occur as chlorine disinfection by-products (DBPs) in swimming pools and hot tubs. UV treatment is a commonly used technique in swimming pools for disinfection and DBP attenuation. UV irradiation is known to efficiently degrade N-nitrosamines. However, UV irradiation (at λ = 254 nm) of chlorinated dimethylamine (CDMA) and monochloramine, two NDMA precursors present in swimming pool water, resulted in a substantial UV-induced NDMA formation (~1-2% molar yield based on initial CDMA concentration) simultaneously to NDMA photolysis. Maximum NDMA concentrations were found at UV doses in the range used for advanced oxidation (350-850 mJ cm(-2)). Very similar behaviour was found for other chlorinated secondary amines, namely diethylamine and morpholine. Effectiveness of UV irradiation for N-nitrosamine abatement depends on initial N-nitrosamine and precursor concentrations and the applied UV dose. N-Nitrosamine formation is hypothesized to occur via the reaction of nitric oxide or peroxynitrite with the secondary aminyl radical, which are products from the photolysis of monochloramine and chlorinated secondary amines, respectively. Experiments with pool water showed that similar trends were observed under pool water conditions. UV treatment (UV dose: ~360 mJ cm(-2)) slightly increased NDMA concentration in pool water instead of the anticipated 50% abatement in the absence of NDMA precursors.

  15. Role and Effectiveness of Percutaneous Arterial Embolization in Hemodynamically Unstable Patients with Ruptured Splanchnic Artery Pseudoaneurysms

    SciTech Connect

    Dohan, Anthony; Eveno, Clarisse; Dautry, Raphael Guerrache, Youcef; Camus, Marine; Boudiaf, Mourad; Gayat, Etienne; Dref, Olivier Le Sirol, Marc Soyer, Philippe

    2015-08-15

    PurposeTo assess the role and effectiveness of percutaneous arterial embolization (TAE) in patients with hemodynamic instability due to hypovolemic shock secondary to ruptured splanchnic artery pseudoaneurysms (SAPA).Materials and MethodsSeventeen patients (11 men, 6 women; mean age, 53 years) with hemodynamic instability (systolic blood pressure <90 mmHg) due to hypovolemic shock secondary to ruptured SAPA were treated by TAE. Clinical files, multidetector row computed tomography angiography, and angiographic examinations along with procedure details were reviewed.ResultsSeventeen SAPAs were present, predominantly located on gastroduodenal or pancreatic arteries (9/17; 53 %). Angiography showed extravasation of contrast medium from SAPA in 15/17 patients (88 %). Technical success rate of TAE was 100 %. TAE was performed using metallic coils in all patients (100 %), in association with gelatin sponge in 5/17 patients (29 %). TAE allowed controlling the bleeding and returning to normal hemodynamic status in 16/17 patients (94 %). In 1/17 patient (6 %), surgery was needed to definitively control the bleeding. The mortality and morbidity rate of TAE at 30 days were 0 and 12 %, respectively. Morbidity consisted in coil migration in 1/17 patient (6 %) and transient serum liver enzyme elevation in 1/17 patient (6 %).ConclusionTAE is an effective and safe treatment option for ruptured SAPA in hemodynamically unstable patients, with a success rate of 94 %. Our results suggest that TAE should be the favored option in patients with hemodynamic instability due to ruptured SAPA.

  16. OZONE-ISOPRENE REACTION: RE-EXAMINATION OF THE FORMATION OF SECONDARY ORGANIC AEROSOL

    EPA Science Inventory

    The reaction of ozone and isoprene has been studied to examine physical and chemical characteristics of the secondary organic aerosol formed. Using a scanning mobility particle sizer, the volume distribution of the aerosol was found in the range 0.05 - 0.2 µm. The aerosol yield w...

  17. Professional Identity Formation as a Framework in Working with Preservice Secondary Teacher Candidates

    ERIC Educational Resources Information Center

    Hsieh, Betina

    2016-01-01

    In this article, using the context of a secondary literacy course, the author argues that personal experiences, praxis-based reflective opportunities, and pedagogically-minded assessments are important in shaping an emergent professional identity that effectively integrates literate practices with content instruction. This article examines…

  18. The Formation of Secondary Organic Aerosol from the Isoprene + OH Reaction in the Absence of NOx

    EPA Science Inventory

    The reaction of isoprene (C5H8) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog ch...

  19. Giant saphenous vein graft pseudoaneurysm to right posterior descending artery presenting with superior vena cava syndrome.

    PubMed

    Vargas-Estrada, Andres; Edwards, Dianna; Bashir, Mohammad; Rossen, James; Zahr, Firas

    2015-06-26

    Saphenous vein grafts (SVG) pseudoaneurysms, especially giant ones, are rare and occur as a late complication of coronary artery bypass grafting. This condition affects both genders and typically occurs within the sixth decade of life. The clinical presentation ranges from an asymptomatic incidental finding on imaging studies to new onset angina, dyspnea, myocardial infarction or symptoms related to compression of neighboring structures. An 82-year-old woman presented with acute onset back pain, dyspnea and was noted to have significantly engorged neck veins. In the emergency department, a chest computed tomographic angiogram with intravenous contrast revealed a ruptured giant bilobed SVG pseudoaneurysm to the right posterior descending artery (RPDA). This imaging modality also demonstrated compression of the superior vena cava (SVC) by the SVG pseudoaneurysm. Coronary angiogram with bypass study was performed to establish the patency of this graft. Endovascular coiling and embolization of the SVG to RPDA was initially considered but disfavored after the coronary angiogram revealed preserved flow from the graft to this arterial branch. After reviewing the angiogram films, a surgical strategy was favored over a percutaneous intervention with a Nitinol self-expanding stent since the latter would have not addressed the superior vena cava compression caused by the giant pseudoaneurysm. Intraoperative transesophageal echocardiogram demonstrated SVC compression by the giant pseudoaneurysm cranial lobe. Our patient underwent surgical ligation and excision of the giant pseudoaneurysm and the RPDA was regrafted successfully. In summary, saphenous vein grafts pseudoaneurysms can be life-threatening and its therapy should be guided based on the presence of mechanical complications, the patency of the affected vein graft and the involved myocardial territory viability.

  20. Giant saphenous vein graft pseudoaneurysm to right posterior descending artery presenting with superior vena cava syndrome

    PubMed Central

    Vargas-Estrada, Andres; Edwards, Dianna; Bashir, Mohammad; Rossen, James; Zahr, Firas

    2015-01-01

    Saphenous vein grafts (SVG) pseudoaneurysms, especially giant ones, are rare and occur as a late complication of coronary artery bypass grafting. This condition affects both genders and typically occurs within the sixth decade of life. The clinical presentation ranges from an asymptomatic incidental finding on imaging studies to new onset angina, dyspnea, myocardial infarction or symptoms related to compression of neighboring structures. An 82-year-old woman presented with acute onset back pain, dyspnea and was noted to have significantly engorged neck veins. In the emergency department, a chest computed tomographic angiogram with intravenous contrast revealed a ruptured giant bilobed SVG pseudoaneurysm to the right posterior descending artery (RPDA). This imaging modality also demonstrated compression of the superior vena cava (SVC) by the SVG pseudoaneurysm. Coronary angiogram with bypass study was performed to establish the patency of this graft. Endovascular coiling and embolization of the SVG to RPDA was initially considered but disfavored after the coronary angiogram revealed preserved flow from the graft to this arterial branch. After reviewing the angiogram films, a surgical strategy was favored over a percutaneous intervention with a Nitinol self-expanding stent since the latter would have not addressed the superior vena cava compression caused by the giant pseudoaneurysm. Intraoperative transesophageal echocardiogram demonstrated SVC compression by the giant pseudoaneurysm cranial lobe. Our patient underwent surgical ligation and excision of the giant pseudoaneurysm and the RPDA was regrafted successfully. In summary, saphenous vein grafts pseudoaneurysms can be life-threatening and its therapy should be guided based on the presence of mechanical complications, the patency of the affected vein graft and the involved myocardial territory viability. PMID:26131340

  1. Assessment of secondary bubble formation on a backward-facing step geometry

    NASA Astrophysics Data System (ADS)

    Juste, G. L.; Fajardo, P.; Guijarro, A.

    2016-07-01

    Flow visualization experiments and numerical simulations were performed on a narrow three-dimensional backward-facing step (BFS) flow with the main objective of characterizing the secondary bubble appearing at the top wall. The BFS has been widely studied because of its geometrical simplicity as well as its ability to reproduce most of the flow features appearing in many applications in which separation occurs. A BFS test rig with an expansion ratio of 2 and two aspect ratios (AR = 4 and AR = 8) was developed. Tests were performed at range of Reynolds numbers ranging from 50 to 1000; visualization experiments provided a qualitative description of secondary bubble and wall-jet flows. Large eddy simulations were carried out with two different codes for validation. Numerical solutions, once validated with experimental data from the literature, were used to acquire a deeper understanding of the experimental visualizations, to characterize the secondary bubble as a function of the flow variables (Reynolds and AR) and to analyze the effect of the secondary bubble on primary reattachment length. Finally, to decouple the sidewall effects due to the non-slip condition and the intrinsic flow three-dimensionality, numerical experiments with free-slip conditions over the sidewalls were computed. The main differences were as follows: When the non-slip condition is used, the secondary bubble appears at a Reynolds number of approximately 200, increases with the Reynolds number, and is limited to a small part of the span. This recirculation zone interacts with the wall-jets and causes the maximum and minimum lengths in the reattachment line of the primary recirculation. Under free slip conditions, the recirculation bubble appears at a higher Reynolds number and covers the entire channel span.

  2. Unpacking the Formative Assessment Processes of Secondary Mathematics Teachers Who Use Wireless Networked Classroom Technology

    ERIC Educational Resources Information Center

    Roble, Amanda Jean

    2015-01-01

    The use of formative assessment can increase student achievement (Black & Wiliam, 1998a). However, some of the challenges of incorporating formative assessment into instruction include the length of time needed to collect, assess and provide feedback to all students and dealing with students misunderstandings and incorrect answers that are…

  3. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae

    PubMed Central

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

  4. Key parameters controlling OH-initiated formation of secondary organic aerosol in the aqueous phase (aqSOA)

    NASA Astrophysics Data System (ADS)

    Ervens, Barbara; Sorooshian, Armin; Lim, Yong B.; Turpin, Barbara J.

    2014-04-01

    Secondary organic aerosol formation in the aqueous phase of cloud droplets and aerosol particles (aqSOA) might contribute substantially to the total SOA burden and help to explain discrepancies between observed and predicted SOA properties. In order to implement aqSOA formation in models, key processes controlling formation within the multiphase system have to be identified. We explore parameters affecting phase transfer and OH(aq)-initiated aqSOA formation as a function of OH(aq) availability. Box model results suggest OH(aq)-limited photochemical aqSOA formation in cloud water even if aqueous OH(aq) sources are present. This limitation manifests itself as an apparent surface dependence of aqSOA formation. We estimate chemical OH(aq) production fluxes, necessary to establish thermodynamic equilibrium between the phases (based on Henry's law constants) for both cloud and aqueous particles. Estimates show that no (currently known) OH(aq) source in cloud water can remove this limitation, whereas in aerosol water, it might be feasible. Ambient organic mass (oxalate) measurements in stratocumulus clouds as a function of cloud drop surface area and liquid water content exhibit trends similar to model results. These findings support the use of parameterizations of cloud-aqSOA using effective droplet radius rather than liquid water volume or drop surface area. Sensitivity studies suggest that future laboratory studies should explore aqSOA yields in multiphase systems as a function of these parameters and at atmospherically relevant OH(aq) levels. Since aerosol-aqSOA formation significantly depends on OH(aq) availability, parameterizations might be less straightforward, and oxidant (OH) sources within aerosol water emerge as one of the major uncertainties in aerosol-aqSOA formation.

  5. MYB75 functions in regulation of secondary cell wall formation in the Arabidopsis inflorescence stem.

    PubMed

    Bhargava, Apurva; Mansfield, Shawn D; Hall, Hardy C; Douglas, Carl J; Ellis, Brian E

    2010-11-01

    Deposition of lignified secondary cell walls in plants involves a major commitment of carbon skeletons in both the form of polysaccharides and phenylpropanoid constituents. This process is spatially and temporally regulated by transcription factors, including a number of MYB family transcription factors. MYB75, also called PRODUCTION OF ANTHOCYANIN PIGMENT1, is a known regulator of the anthocyanin branch of the phenylpropanoid pathway in Arabidopsis (Arabidopsis thaliana), but how this regulation might impact other aspects of carbon metabolism is unclear. We established that a loss-of-function mutation in MYB75 (myb75-1) results in increased cell wall thickness in xylary and interfascicular fibers within the inflorescence stem. The total lignin content and S/G ratio of the lignin monomers were also affected. Transcript profiles from the myb75-1 inflorescence stem revealed marked up-regulation in the expression of a suite of genes associated with lignin biosynthesis and cellulose deposition, as well as cell wall modifying proteins and genes involved in photosynthesis and carbon assimilation. These patterns suggest that MYB75 acts as a repressor of the lignin branch of the phenylpropanoid pathway. Since MYB75 physically interacts with another secondary cell wall regulator, the KNOX transcription factor KNAT7, these regulatory proteins may form functional complexes that contribute to the regulation of secondary cell wall deposition in the Arabidopsis inflorescence stem and that integrate the metabolic flux through the lignin, flavonoid, and polysaccharide pathways.

  6. Herbivory by an Outbreaking Moth Increases Emissions of Biogenic Volatiles and Leads to Enhanced Secondary Organic Aerosol Formation Capacity.

    PubMed

    Yli-Pirilä, Pasi; Copolovici, Lucian; Kännaste, Astrid; Noe, Steffen; Blande, James D; Mikkonen, Santtu; Klemola, Tero; Pulkkinen, Juha; Virtanen, Annele; Laaksonen, Ari; Joutsensaari, Jorma; Niinemets, Ülo; Holopainen, Jarmo K

    2016-11-01

    In addition to climate warming, greater herbivore pressure is anticipated to enhance the emissions of climate-relevant biogenic volatile organic compounds (VOCs) from boreal and subarctic forests and promote the formation of secondary aerosols (SOA) in the atmosphere. We evaluated the effects of Epirrita autumnata, an outbreaking geometrid moth, feeding and larval density on herbivore-induced VOC emissions from mountain birch in laboratory experiments and assessed the impact of these emissions on SOA formation via ozonolysis in chamber experiments. The results show that herbivore-induced VOC emissions were strongly dependent on larval density. Compared to controls without larval feeding, clear new particle formation by nucleation in the reaction chamber was observed, and the SOA mass loadings in the insect-infested samples were significantly higher (up to 150-fold). To our knowledge, this study provides the first controlled documentation of SOA formation from direct VOC emission of deciduous trees damaged by known defoliating herbivores and suggests that chewing damage on mountain birch foliage could significantly increase reactive VOC emissions that can importantly contribute to SOA formation in subarctic forests. Additional feeding experiments on related silver birch confirmed the SOA results. Thus, herbivory-driven volatiles are likely to play a major role in future biosphere-vegetation feedbacks such as sun-screening under daily 24 h sunshine in the subarctic.

  7. Secondary Eyewall Formation in Two Idealized, Full-Physics Modeled Hurricanes

    DTIC Science & Technology

    2008-06-26

    eyewall initiation, testing and drawing ideas from previous hypotheses for this complex process. Prior formation hypotheses are summarized and many are...Montgomery and Brunet, 2002]. It is from this viewpoint that we propose the following second- ary eyewall formation hypothesis for testing . 4.3. Hypothesis... tested and used operationally with current hurricane obser- vational methods. Accurate azimuthal mean wind profiles can be computed from dropsonde and

  8. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

    NASA Astrophysics Data System (ADS)

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2015-09-01

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool which explicitly represents SOA formation and gas/wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas/wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up to 0.35 yield unit due to the loss of organic vapors to chamber walls.

  9. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

    NASA Astrophysics Data System (ADS)

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2016-02-01

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas-wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas-wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.

  10. Endovascular Management of Visceral Artery Pseudoaneurysms: Transcatheter Coil Embolization Using the Isolation Technique

    SciTech Connect

    Ikeda, Osamu Nakasone, Yutaka; Tamura, Yoshitaka; Yamashita, Yasuyuki

    2010-12-15

    PurposeTo describe our experiences with treatment of visceral artery pseudoaneurysms (VAPA) by transcatheter coil embolization using an isolation technique and to propose indications for treating VAPA with this method.Materials and MethodsWe treated 37 patients with VAPA endovascularly: There were 15 pancreaticoduodenal arcade, 10 hepatic, 5 renal, 3 splenic, and 1 each left gastric, gastroepiploic, adrenal, and superior mesenteric artery pseudoaneurysms. Preprocedure computed tomography (CT) and/or angiographic studies confirmed the presence of VAPA in all 37 patients. Using the isolation technique, we embolized vessels at sites distal and proximal to the pseudoaneurysm.ResultsTranscatheter coil embolization with the isolation technique was technically successful in 33 (89%) of 37 patients, and angiogram confirmed the complete disappearance of the VAPA in 32 patients. No major complications occurred during the procedures. In a patient with a pancreaticoduodenal arcade artery pseudoaneurysm, we were unable to control hemorrhage. In 30 of 32 patients who recovered after transcatheter coil embolization using the isolation technique, follow-up CT scan showed no flow in VAPA; they survived without rebleeding. Two of the 32 patients (6%) with confirmed complete disappearance of VAPA on angiogram and CT scan obtained the day after the procedure manifested rebleeding during follow-up.ConclusionTranscatheter coil embolization using the isolation technique is an effective alternative treatment in patients with VAPA. In combination with coil embolization, the isolation technique is particularly useful in patients whose pseudoaneurysms present surgical difficulties.

  11. Percutaneous Stent-Graft Repair of a Mycotic Pulmonary Artery Pseudoaneurysm

    SciTech Connect

    Chou Meichun; Liang Hueilung Pan Huayban; Yang Chienfang

    2006-10-15

    Ruptured mycotic pulmonary pseudoaneurysm is a lethal complication. Emergent surgical repair is usually recommended, but still associated with a high mortality rate. We present a patient in whom mycotic pulmonary pseudoaneurysm was a complication after surgical lobectomy 2 weeks earlier. This patient had suffered from repeated massive hemoptysis. After emergent surgical repair of the ruptured pulmonary artery stump, another episode of massive hemorrhage occurred. The pulmonary arteriogram revealed a segmental stenosis and a large, wide-necked, lobulated pseudoaneurysm at the left proximal pulmonary artery. We deployed a balloon-expandable stent-graft (48 mm in length mounted on a 12 mm x 40 mm angioplasty balloon) across the stenotic segment and the neck of the pulmonary pseudoaneurysm. Hemostasis was achieved immediately and, under a 4-week antibiotic treatment, patient was transferred to a local hospital for medical care. This case report demonstrates the benefit of minimally invasive endovascular therapy in a critically ill patient. A literature review of the etiology and management of mycotic pulmonary pseudoaneurysm is included.

  12. Nonsurgical repair of a pseudoaneurysm in a cynomolgus macaque (Macaca fascicularis).

    PubMed

    Daviau, Judith S; Merton, Daniel A

    2010-09-01

    A cynomolgus macaque presented with an ecchymotic and edematous left leg approximately 1 wk after a blood sample had been collected from the left femoral vein. Ecchymosis was noted in the femoral triangle, prepuce, and scrotum. The animal was not febrile or exhibiting signs of pain or distress. Duplex Doppler ultrasound imaging was used to evaluate the area. An arteriovenous fistula between the femoral artery and vein, accompanied by a pseudoaneurysm arising from the femoral artery, was identified. Various invasive and noninvasive treatment options for the pseudoaneurysm, including surgical repair, thrombin injection, stent placement, and ultrasound-guided compression repair (UGCR), were considered. UGCR was chosen as the first option for treatment. After a total of 20 min of UGCR at the neck of the pseudoaneurysm, complete thrombosis was achieved. Subsequent imaging of the lesion revealed resolution of the pseudoaneurysm. Because of the risks involved with invasive management techniques for this vascular lesion, UGCR is a valuable noninvasive treatment option for the repair of pseudoaneurysms.

  13. Nonsurgical Repair of a Pseudoaneurysm in a Cynomolgus Macaque (Macaca fascicularis)

    PubMed Central

    Daviau, Judith S; Merton, Daniel A

    2010-01-01

    A cynomolgus macaque presented with an ecchymotic and edematous left leg approximately 1 wk after a blood sample had been collected from the left femoral vein. Ecchymosis was noted in the femoral triangle, prepuce, and scrotum. The animal was not febrile or exhibiting signs of pain or distress. Duplex Doppler ultrasound imaging was used to evaluate the area. An arteriovenous fistula between the femoral artery and vein, accompanied by a pseudoaneurysm arising from the femoral artery, was identified. Various invasive and noninvasive treatment options for the pseudoaneurysm, including surgical repair, thrombin injection, stent placement, and ultrasound-guided compression repair (UGCR), were considered. UGCR was chosen as the first option for treatment. After a total of 20 min of UGCR at the neck of the pseudoaneurysm, complete thrombosis was achieved. Subsequent imaging of the lesion revealed resolution of the pseudoaneurysm. Because of the risks involved with invasive management techniques for this vascular lesion, UGCR is a valuable noninvasive treatment option for the repair of pseudoaneurysms. PMID:20858370

  14. Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

    NASA Astrophysics Data System (ADS)

    Liu, Shang; Ahlm, Lars; Day, Douglas A.; Russell, Lynn M.; Zhao, Yunliang; Gentner, Drew R.; Weber, Robin J.; Goldstein, Allen H.; Jaoui, Mohammed; Offenberg, John H.; Kleindienst, Tadeusz E.; Rubitschun, Caitlin; Surratt, Jason D.; Sheesley, Rebecca J.; Scheller, Scott

    2012-12-01

    Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemical and physical properties of SOA at Bakersfield, California, a site influenced by anthropogenic and terrestrial biogenic emissions. Factor analysis was applied to the infrared and mass spectra of fine particles to identify sources and atmospheric processing that contributed to the organic mass (OM). We found that OM accounted for 56% of submicron particle mass, with SOA components contributing 80% to 90% of OM from 15 May to 29 June 2010. SOA formed from alkane and aromatic compounds, the two major classes of vehicle-emitted hydrocarbons, accounted for 65% OM (72% SOA). The alkane and aromatic SOA components were associated with 200 nm to 500 nm accumulation mode particles, likely from condensation of daytime photochemical products of VOCs. In contrast, biogenic SOA likely formed from condensation of secondary organic vapors, produced from NO3radical oxidation reactions during nighttime hours, on 400 nm to 700 nm sized primary particles, and accounted for less than 10% OM. Local petroleum operation emissions contributed 13% to the OM, and the moderate O/C (0.2) of this factor suggested it was largely of secondary origin. Approximately 10% of organic aerosols in submicron particles were identified as either vegetative detritus (10%) or cooking activities (7%), from Fourier transform infrared spectroscopic and aerosol mass spectrometry measurements, respectively. While the mass spectra of several linearly independent SOA components were nearly identical and external source markers were needed to separate them, each component had distinct infrared spectrum, likely associated with the source-specific VOCs from which they formed.

  15. Effect of preparation conditions on protein secondary structure and biofilm formation of kafirin.

    PubMed

    Gao, Chunli; Taylor, Janet; Wellner, Nikolaus; Byaruhanga, Yusuf B; Parker, Mary L; Mills, E N Clare; Belton, Peter S

    2005-01-26

    Various extraction and drying conditions for the isolation of kafirin from dry-milled, whole grain sorghum have been investigated, with a view to optimizing extraction of the protein for commercial food coatings and packaging films. The addition of sodium hydroxide to an aqueous ethanol extractant increased the yield and solubility of kafirin. Subsequent heat drying at 40 degrees C was shown to cause the kafirin to aggregate as indicated by an increase in intermolecular beta-sheets. Extraction of the flour using ethanol (70%, w/w) with 0.5% (w/w) sodium metabisulfite and 0.35% (w/w) sodium hydroxide at 70 degrees C followed by freeze-drying of the protein was found to produce a yield of 54% kafirin with good film-forming properties. The kafirin films were assessed for their sensory properties, tensile strength, strain, and water vapor permeability. Fourier transform infrared spectroscopy was used to study the secondary structure of the extracted kafirins. The best films were made with kafirin containing a large proportion of nativelike alpha-helical structures with little intermolecular beta-sheet content as indicated by the Fourier transform infrared reflectance peak intensity ratios associated with these secondary structures. The principal factor affecting the secondary structure of the protein appeared to be the temperature at which the protein was dried. Heat drying resulted in a greater proportion of intermolecular beta-sheets. Any industrial-scale extraction must therefore minimize protein aggregation and maximize native alpha-helical structures to achieve optimal film quality.

  16. Loss of INCREASED SIZE EXCLUSION LIMIT (ISE)1 or ISE2 increases the formation of secondary plasmodesmata.

    PubMed

    Burch-Smith, Tessa M; Zambryski, Patricia C

    2010-06-08

    Plasmodesmata (PD) transport developmentally important nucleic acids and proteins between plant cells. Primary PD form during cell division and are simple, linear channels. Secondary PD form in existing cell walls after cell division and are simple, twinned, or branched. PD function undergoes a marked reduction at the mid-torpedo stage of Arabidopsis embryogenesis. Two mutants, increased size exclusion limit (ise)1 and ise2, fail to undergo this transition, and their null mutations are embryonically lethal. We investigated the ultrastructure of PD in early-, mid-, and late-torpedo-stage embryos and in young leaves. Wild-type (WT) embryos contain twinned and branched (T/B) PD at all stages, but ise1 and ise2 embryos contain significantly higher proportions of T/B PD than WT embryos. WT T/B PD formation occurs in a stage- and tissue-specific pattern that is reversed in ise1 embryos. Silencing ISE1 in Nicotiana benthamiana leaves increases the frequency of secondary PD in existing cell walls. Silencing ISE2 increases the proportion of T/B secondary PD formed. Silenced tissues exhibit increased PD-mediated movement of green fluorescent protein tracers. Thus, silencing of ISE1 and ISE2 phenocopies ise1 and ise2 mutant embryos: when wild-type ISE1 and ISE2 functions are lost, de novo production of PD occurs, leading to increased intercellular transport.

  17. Comparing secondary organic aerosol formation in two U.S. cities

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-12-01

    Secondary organic aerosols (SOAs) form from the oxidation of volatile organic compounds (VOCs) in the atmosphere, and the composition and abundance of SOAs determine their effects on air quality, human health, and the planetary radiation budget. To investigate how the production of SOAs varies with location, Zhang et al. conducted a parallel set of experiments in Los Angeles, Calif., and Atlanta, Ga. Both cities see a large amount of volatile organic compounds thrown into the air because of anthropogenic emissions, largely stemming from vehicles. Atlanta, unlike Los Angeles, also sees a large amount of biogenic emissions from vegetation in the region.

  18. Secondary abscess formation in pituitary adenoma after tooth extraction. Case report.

    PubMed

    Kroppenstedt, S N; Liebig, T; Mueller, W; Gräf, K J; Lanksch, W R; Unterberg, A W

    2001-02-01

    The presence of an abscess in a pituitary tumor is a very rare finding. The authors report the case of a 69-year-old man with a pituitary adenoma confirmed by neuroimaging results, in whom a high fever, meningismus, and left-sided ophthalmoplegia developed 4 days after tooth extraction. The results of serial cranial magnetic resonance imaging were highly indicative of an abscess formation within the pituitary adenoma. During surgery the tumor was approached transsphenoidally and removed. Histological examination confirmed the presence of an abscess formation within the pituitary adenoma. It is most likely that the tooth extraction caused a bacteremia, which led to an inflammation with abscess formation within the pituitary adenoma. The authors conclude that invasive dental procedures should be avoided before planned resection of a pituitary adenoma.

  19. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; Day, Douglas A.; Kaser, Lisa; Jud, Werner; Karl, Thomas; Hansel, Armin; Hunter, James F.; Cross, Eben S.; Kroll, Jesse H.; Peng, Zhe; Brune, William H.; Jimenez, Jose L.

    2016-03-01

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen-Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed for semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m-3 when LVOC fate corrected) compared to daytime (average 0.9 µg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic

  20. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    DOE PAGES

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; ...

    2016-03-08

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen–Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed formore » semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m−3 when LVOC fate corrected) compared to daytime (average 0.9 µg m−3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of

  1. Impacts of oxidation aging on secondary organic aerosol formation, particle growth rate, cloud condensation nuclei abundance, and aerosol climate forcing

    NASA Astrophysics Data System (ADS)

    Yu, F.; Luo, G.

    2014-12-01

    Particle composition measurements indicate that organic aerosol (OA) makes up ~20-90% of submicron particulate mass and secondary OA (SOA) accounts for a large fraction (~ 72 ±21%) of these OA masses at many locations around the globe. The volatility changes of secondary organic gases (SOG) associated with oxidation aging as well as the contribution of highly oxidized low volatile SOG (LV-SOG) to the condensational growth of secondary particles have been found to be important in laboratory and field measurements but are poorly represented in global models. A novel scheme to extend the widely used two-product SOA formation model, by adding a third product arising from the oxidation aging (i.e., LV-SOG) and considering the dynamic transfer of mass from higher to lower volatile products, has been developed and implemented into a global chemical transport model (GEOS-Chem) and a community atmosphere model (CESM-CAM5). The scheme requires only minor changes to the existing two-product SOA formation model and is computationally efficient. With the oxidation rate constrained by laboratory measurements, we show that the new scheme predicts a much higher SOA mass concentrations, improving the agreement with aerosol mass spectrometer SOA measurements. The kinetic condensation of LV-SOG on ultrafine particles, simulated by a size-resolved (sectional) advanced particle microphysics (APM) model incorporated into in GEOS-Chem and CAM5, increases the particle growth rate substantially and improves the agreement of simulated cloud condensation nuclei (CCN) concentrations with observations. Based on GEOS-Chem-APM simulations, the new SOA formation scheme increases global mean low troposphere SOA mass concentration by ~130% and CCN abundance by ~ 15%, and optical depth of secondary particles and coated black carbon and primary organic carbon particles by ~10%. As a result, aerosol radiative cooling effect (direct + first indirect) is enhanced by -0.9 W/m2, with large spatial

  2. Virus-induced gene silencing of P23k in barley leaf reveals morphological changes involved in secondary wall formation.

    PubMed

    Oikawa, Ai; Rahman, Abidur; Yamashita, Tetsuro; Taira, Hideharu; Kidou, Shin-Ichiro

    2007-01-01

    P23k is a monocot-unique protein that is highly expressed in the scutellum of germinating barley seed. Previous expression analyses suggested that P23k is involved in sugar translocation and/or sugar metabolism. However, the role of P23k in barley physiology remains unclear. Here, to elucidate its physiological function, BSMV-based virus-induced gene silencing (VIGS) of P23k in barley leaves was performed. Expression and localization analyses of P23k mRNA in barley leaves showed up-regulation of P23k transcript with increased photosynthetic activity and the localization of these transcripts to the vascular bundles and sclerenchyma, where secondary wall formation is most active. VIGS of the P23k gene led to abnormal leaf development, asymmetric orientation of main veins, and cracked leaf edges caused by mechanical weakness. In addition, histochemical analyses indicated that the distribution of P23k in leaves coincides with the distribution of cell wall polysaccharides. Considering these results together, it is proposed that P23k is involved in the synthesis of cell wall polysaccharides and contributes to secondary wall formation in barley leaves.

  3. Multiple secondary islands formation in nonlinear evolution of double tearing mode simulations

    NASA Astrophysics Data System (ADS)

    Guo, W.; Ma, J.; Yu, Z.

    2017-03-01

    A new numerical code solving the conservative perturbed resistive magnetohydrodynamic (MHD) model is developed. Numerical tests of the ideal Kelvin-Helmholtz instability and the resistive double tearing mode (DTM) show its capability in solving linear and nonlinear MHD instabilities. The nonlinear DTM evolution in 2D geometry is numerically investigated with low guiding field B z 0 , short half-distance y 0 between the equilibrium current sheets, and small resistivity η. The interaction of islands on the two initial current sheets may generate an unstable flow driven current sheet with a high length-to-thickness aspect ratio (α), and multiple secondary islands can form. In general, the length-to-thickness aspect ratio α and the number of secondary islands increase with decreasing guide field B z 0 , decreasing half-distance y 0 , and increasing Lundquist number of the flow driven current sheet S L although the dependence may be non-monotonic. The reconnection rate dependence on S L , B z 0 , and y 0 is also investigated.

  4. Prevention of PCDD/F formation and minimization of their emission at the stack of a secondary aluminum casting plant.

    PubMed

    Pitea, Demetrio; Bortolami, Michele; Collina, Elena; Cortili, Gabriele; Franzoni, Francesco; Lasagni, Marina; Piccinelli, Elsa

    2008-10-01

    Results of an extensive 5 year study on a full-scale plant with the specific aim to investigate polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzo furan (PCDF) formation and release in a secondary aluminum casting plant are reported. PCDD and PCDF concentrations were evaluated for all the gaseous and solid streams (no liquid stream was present) as well as for the flue gas upstream and downstream of every single unit of the flue gas cleaning system. The study highlights PCDD and PCDF formation particularly in the narrow 320-360 degrees C range. To prevent formation reactions and/or minimize PCDD and PCDF concentration at the stack, effects of the fabric filter substitution, a quenching chamber and a postcombustor installation together with working conditions are investigated. The flue gas cleaning system results in PCDD and PCDF emission at stack of 0.1-0.2 ng I-TEQ/N m3 and in a mass flow of 250-550 nmol/h. The total PCDD and PCDF release into the environment is 0.06 g I-TEQ/yr and the corresponding emission factor, 0.35 microg I-TEQ/ton. It is shown that the global effects of the technological innovation on the reaction mechanisms are the prevention of PCDD/F formation by de novo synthesis and the minimization of their emission.

  5. Formation of Brown Aqueous Secondary Organic Aerosol during Multiphase Cloud Simulations using the CESAM Chamber Facility

    NASA Astrophysics Data System (ADS)

    Hawkins, L. N.; Welsh, H.; De Haan, D. O.; Doussin, J. F.; Pednekar, R.; Caponi, L.; Pangui, E.; Gratien, A.; Cazaunau, M.; Formenti, P.; Pajunoja, A.

    2015-12-01

    We investigated the formation of aqueous brown carbon (aqBrC) from methylglyoxal and methylamine in multiphase reactions using the CESAM chamber facility at the University Paris-Est Creteil. Following reaction in the chamber, droplets and particles were sampled with a Particle-Into-Liquid-Sampler (PILS), a capillary waveguide cell for UV/visible spectroscopy, and a total organic carbon analyzer (TOC). Particle size distributions were measured with a scanning mobility particle sizer and used to determine the mass absorption coefficient (a normalized absorbance measurement). Absorption spectra were recorded while aerosol or gas phase aqBrC precursors were introduced into the humid chamber. Sampling was continuous during and after cloud events. The events lasted 5-10 minutes and produced measurable brown carbon signal at 365 nm. When lights were used, absorbance at 365 nm decreased steadily indicating photobleaching of aqBrC products or preferential formation of different, non-absorbing products. Although absorptivity increases prior to cloud formation, cloud events produce sharp increased in aqBrC absorptivity. While measurable absorbance at 365 nm indicates aqBrC formation, very little absorbance was recorded beyond 450 nm indicating that the products were not as oligomerized as products observed in prior work in multi-day, bulk phase simulations.

  6. Insights into different nitrate formation mechanisms from seasonal variations of secondary inorganic aerosols in Shanghai

    NASA Astrophysics Data System (ADS)

    Tao, Ye; Ye, Xingnan; Ma, Zhen; Xie, Yuanyuan; Wang, Ruyu; Chen, Jianmin; Yang, Xin; Jiang, Shuqin

    2016-11-01

    The dominant mechanisms for the formation of fine particulate nitrate during four seasons were proposed by evaluating the correlations between [NO3-]/[SO42-] and [NH4+]/[SO42-]. Size-resolved aerosols were collected in Shanghai from April 2013 to January 2014. The concentration of fine particulate nitrate was below one tenth of the concentration of sulfate in summer, whereas fine particulate nitrate dominated over sulfate in winter. Influenced by aged sea salt aerosols, the molar ratio of [Na+]/[NH4+] reached 53 ± 49% and the depletion of chloride was very significant (0.83) during autumn. In spring, the increase of nitrate concentration became evident for [NH4+]/[SO42-]>2, indicating that sulfate is fully neutralized. During summertime, nighttime hydrolysis of N2O5 dominated the fine particulate nitrate formation. The thresholds of [NH4+]/[SO42-] for nitrate formation in autumn and winter were wrongly characterized by the linear regression between [NO3-]/[SO42-] and [NH4+]/[SO42-], because considerable amounts of Na2SO4 and NH4Cl were present. Replaced by free ammonium in the function equation, it was established that the winter and spring aerosols shared the same nitrate formation mechanism. On the basis of free sulfate, it was evident that both homogeneous neutralization and hydrolysis of N2O5 mechanisms were involved during autumn.

  7. Effects of temperature on the formation of secondary organic aerosol from amine precursors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerosol formation is directly influenced by meteorological properties such as temperature and relative humidity. Temperature, for example, directly affects the gas-to-particle partitioning of amine salts and semi-volatile organic amine products. These salts are formed in areas with high agricultur...

  8. Scottish Secondary School Students' Preferences for Location, Format of Counselling and Sex of Counsellor

    ERIC Educational Resources Information Center

    Cooper, Mick

    2006-01-01

    Within the United Kingdom there is a significant revival of therapeutic counselling services in schools. This study looks at three factors which may affect students' willingness to attend such a service: location of the service (school-based or external); format (individual or group); and sex of counsellor. The views of 584 students from four…

  9. Investigating secondary aerosol formation from agricultural amines and reduced sulfur compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gas phase amines and reduced sulfur compounds are often co-emitted from agricultural processes. Amines have been recently recognized as potentially major sources of agricultural aerosol formation, while the reduced sulfur compounds are largely ignored. There is a severe lack of knowledge and under...

  10. Modelling the formation and composition of secondary organic aerosol from α- and β-pinene ozonolysis using MCM v3

    NASA Astrophysics Data System (ADS)

    Jenkin, M. E.

    2004-05-01

    The formation and detailed composition of secondary organic aerosol (SOA) from the gas phase ozonolysis of α- and β-pinene has been simulated using the Master Chemical Mechanism version 3 (MCM v3), coupled with a representation of gas-to-aerosol transfer of semivolatile and involatile oxygenated products. A kinetics representation, based on equilibrium absorptive partitioning of ca. 200 semivolatile products, was found to provide an acceptable description of the final mass concentrations observed in a number of reported laboratory and chamber experiments, provided partitioning coefficients were increased by about two orders of magnitude over those defined on the basis of estimated vapour pressures. This adjustment is believed to be due, at least partially, to the effect of condensed phase association reactions of the partitioning products. Even with this adjustment, the simulated initial formation of SOA was delayed relative to that observed, implying the requirement for the formation of species of much lower volatility to initiate SOA formation. The inclusion of a simplified representation of the formation and gas-to-aerosol transfer of involatile dimers of 22 bi- and multifunctional carboxylic acids (in addition to the absorptive partitioning mechanism) allowed a much improved description of SOA formation for a wide range of conditions. The simulated SOA composition recreates certain features of the product distributions observed in a number of experimental studies, but implies an important role for multifunctional products containing hydroperoxy groups (i.e. hydroperoxides). This is particularly the case for experiments in which 2-butanol is used to scavenge OH radicals, because [HO2]/[RO2] ratios are elevated in such systems. The optimized mechanism is used to calculate SOA yields from α- and β-pinene ozonolysis in the presence and absence of OH scavengers, and as a function of temperature.

  11. Modelling the formation and composition of secondary organic aerosol from α- and β-pinene ozonolysis using MCM v3

    NASA Astrophysics Data System (ADS)

    Jenkin, M. E.

    2004-09-01

    The formation and detailed composition of secondary organic aerosol (SOA) from the gas phase ozonolysis of α- and β-pinene has been simulated using the Master Chemical Mechanism version 3 (MCM v3), coupled with a representation of gas-to-aerosol transfer of semivolatile and involatile oxygenated products. A kinetics representation, based on equilibrium absorptive partitioning of ca. 200 semivolatile products, was found to provide an acceptable description of the final mass concentrations observed in a number of reported laboratory and chamber experiments, provided partitioning coefficients were increased by about two orders of magnitude over those defined on the basis of estimated vapour pressures. This adjustment is believed to be due, at least partially, to the effect of condensed phase association reactions of the partitioning products. Even with this adjustment, the simulated initial formation of SOA was delayed relative to that observed, implying the requirement for the formation of species of much lower volatility to initiate SOA formation. The inclusion of a simplified representation of the formation and gas-to-aerosol transfer of involatile dimers of 22 bi- and multifunctional carboxylic acids (in addition to the absorptive partitioning mechanism) allowed a much improved description of SOA formation for a wide range of conditions. The simulated SOA composition recreates certain features of the product distributions observed in a number of experimental studies, but implies an important role for multifunctional products containing hydroperoxy groups (i.e. hydroperoxides). This is particularly the case for experiments in which 2-butanol is used to scavenge OH radicals, because [HO2]/[RO2] ratios are elevated in such systems. The optimized mechanism is used to calculate SOA yields from α- and β-pinene ozonolysis in the presence and absence of OH scavengers, and as a function of temperature.

  12. Modeling Gas-phase Glyoxal and Associated Secondary Organic Aerosol Formation in a Megacity using WRF/Chem

    NASA Astrophysics Data System (ADS)

    Wang, K.; Hodzic, A.; Barth, M. C.; Jimenez, J. L.; Volkamer, R.; Ervens, B.; Zhang, Y.

    2011-12-01

    Organic aerosol (OA) as one of a major fine particulate matter in the atmosphere plays an important role in air pollution, human health, and climate forcing. OA is composed of directly emitted primary organic aerosol and chemically produced secondary organic aerosols (SOA). Despite much recent progress in understanding SOA formation, current air quality models cannot explain the magnitude and growth of atmospheric SOA, due to high uncertainties in sources, properties, and chemical reactions of precursors and formation pathways of SOA. Recent laboratory and modeling studies showed that glyoxal may serve as an important SOA precursor in the condensed solution of inorganic or organic aerosol particles (e.g., ammonium sulfate, fulvic acid, and amino acids). In this study, the Weather Research and Forecasting model with chemistry (WRF/Chem) is modified to account for the latest observed gas-phase yields of glyoxal from various volatile organic compounds (VOCs) and the associated SOA formation in the aqueous aerosol phase. The SOA formation in the aqueous aerosol phase is implemented using two approaches. In the first approach, two simplified parameterizations are used to represent the lumped particle-phase chemical processes under dark conditions and photochemical surface uptake. In the second approach, more detailed kinetic glyoxal reactions such as reversible glyoxal uptake, dimer formation of glyoxal, and oligomerization are treated and resolved explicitly. The updated WRF/Chem is assessed over the Mexico City and the surrounding region during March 2006 using the MILAGRO campaign data. Various observations such as organic matter from Aerodyne Aerosol Mass Spectrometer and VOCs from Proton-transfer Ion Trap Mass Spectrometry were compared. The preliminary results showed that the addition of the SOA formation from glyoxal in aqueous particles brings SOA predictions into a better agreement with field observations, in particular in presence of high relative humidity

  13. Endovascular Treatment of Anastomotic Pseudoaneurysms after Aorto-iliac Surgical Reconstruction

    SciTech Connect

    Lagana, Domenico Carrafiello, Gianpaolo; Mangini, Monica Recaldini, Chiara; Lumia, Domenico; Cuffari, Salvatore; Caronno, Roberto; Castelli, Patrizio; Fugazzola, Carlo

    2007-11-15

    Purpose. To assess the effectiveness of endovascular treatment of anastomotic pseudoaneurysms (APAs) following aorto-iliac surgical reconstruction. Materials. We retrospectively evaluated 21 men who, between July 2000 and March 2006, were observed with 30 APAs, 13 to the proximal anastomosis and 17 to the distal anastomosis. The patients had had previous aorto-iliac reconstructive surgery with a bypass due to aneurysm (15/21) or obstructive disease (6/21). The following devices were used: 12 bifurcated endoprostheses, 2 aorto-monoiliac, 4 aortic extenders, 1 stent-graft leg, and 2 covered stents. Follow-up was performed with CT angiography at 1, 3, and 6 months after the procedure and yearly thereafter. Results. Immediate technical success was 100%. No periprocedural complications occurred. Four patients died during follow-up from causes not related to APA, and 1 (treated for prosthetic-enteric fistula) from sepsis 3 months after the procedure. During a mean follow-up of 19.7 months (range 1-72 months), 2 of 21 occlusions of stent-graft legs occurred 3 and 24 months after the procedure (treated with thrombolysis and percutaneous transluminal angioplasty and femorofemoral bypass, respectively) and 1 type I endoleak. Primary clinical success rate was 81% and secondary clinical success was 91%. Conclusion. Endovascular treatment is a valid alternative to open surgery and can be proposed as the treatment of choice for APAs, especially in patients who are a high surgical risk. Further studies with larger series and longer follow-up are necessary to confirm the long-term effectiveness of this approach.

  14. Endovascular Treatment of Visceral Aneurysms and Pseudoaneurysms: Long-term Outcomes from a Multicenter European Study

    SciTech Connect

    Spiliopoulos, Stavros Sabharwal, Tarun; Karnabatidis, Dimitrios; Brountzos, Elias; Katsanos, Konstantinos; Krokidis, Miltiadis; Gkoutzios, Panagiotis; Siablis, Dimitrios; Adam, Andreas

    2012-12-15

    Purpose: To investigate the percutaneous endovascular management of visceral aneurysms (VA) and visceral pseudoaneurysms (VPA) treated in three European interventional radiology departments. Methods: Patient archives from the department's databases were examined and retrospectively analyzed. Patients diagnosed between 2000 and 2010 with VA and/or VPA, confirmed by computed tomography angiography, magnetic resonance angiography, or digital subtraction angiography and treated exclusively with percutaneous endovascular methods, were included in the study. The study's primary end points were procedural technical success, target lesion reintervention rate, and periprocedural mortality rate. Secondary end points included major and minor complications rates. Results: The medical records of 54 patients (41 male, mean age 55 {+-} 18.1 years) with 58 VAs or VPAs and treated with various percutaneous endovascular therapeutic modalities were analyzed. In total, 21 VAs (mean diameter 49.4 {+-} 21 mm, range 20-100 mm) and 37 VPAs (mean diameter 25.1 {+-} 14.6 mm, range 8-60 mm) were treated. Procedural technical success was achieved in 100% of the cases, while target lesion reintervention rate was 6.1% (2 of 33) and 14.2% (3 of 21) in the VPA and VA groups, respectively. Mean clinical follow-up period was 19.1 {+-} 21.4 months. Overall periprocedural mortality rate was 3% (1 of 33) in the VPA group and 0% (0 of 21) in the VA group. Conclusion: Percutaneous endovascular treatment of VAs and VPAs is safe and effective with low morbidity and mortality. There is a small but significant reintervention rate, particularly for true aneurysms; dedicated follow-up imaging is recommended. Successful aneurysm exclusion was achieved in all cases with a second procedure.

  15. Functionalization vs. fragmentation: n-aldehyde oxidation mechanisms and secondary organic aerosol formation.

    PubMed

    Chacon-Madrid, Heber J; Presto, Albert A; Donahue, Neil M

    2010-11-14

    Because of their relatively well-understood chemistry and atmospheric relevance, aldehydes represent a good model system for carbon-carbon fragmentation reactions in organic-aerosol aging mechanisms. Small aldehydes such as ethanal and propanal react with OH radicals under high NO(x) conditions to form formaldehyde and ethanal, respectively, with nearly unit yield. CO(2) is formed as a coproduct. This path implies the formation of the C(n-1) aldehyde, or an aldehyde with one fewer methylene group than the parent. However, as the carbon number of the n-aldehyde increases, reaction with the carbon backbone becomes more likely and the C(n-1) formation path becomes less important. In this work we oxidized n-pentanal, n-octanal, n-undecanal and n-tridecanal with OH radicals at high NO(x). The C(n-1) aldehyde molar yields after the peroxyl radical + NO reaction were 69 ± 15, 36 ± 10, 16 ± 5 and 4 ± 1%, respectively. Complementary structure-activity relationship calculations of important rate constants enable estimates of branching ratios between several intermediates of the C(n)n-aldehyde reaction with OH: C(n) peroxyacyl nitrate versus C(n) alkoxyacyl radical formation, C(n-1) alkyl nitrate versus C(n-1) alkoxy radical, and C(n-1) aldehyde formation versus isomerization products. We also measured SOA mass yields, which we compare with analogous n-alkanes to understand the effect of fragmentation on organic-aerosol formation.

  16. An Unusual Left Ventricular Outflow Pseudoaneurysm: Usefulness of Echocardiography and Multidetector Computed Tomography for Surgical Repair

    SciTech Connect

    Da Col, Uberto; Ramoni, Enrico Di Bella, Isidoro; Ragni, Temistocle

    2009-01-15

    Left ventricular outflow tract (LVOT) pseudoaneurysm is a rare but potentially lethal complication, mainly after aortic root endocarditis or surgery. Usually it originates from a dehiscence in the mitral-aortic intervalvular fibrosa and it arises posteriorly to the aortic root. Due to these anatomical features, its imaging assessment is challenging and surgical repair requires complex procedures. An unusual case of LVOT pseudoaneurysm is described. It was detected by transthoracic ecocardiography 7 months after aortic root replacement for acute endocarditis. Multidetector computed tomography (MDCT) confirmed the presence of a pouch located between the aortic root and the right atrium. Computed tomography also detected the origin of the pseudoaneurysm from the muscular interventricular septum of the LVOT, rather below the aortic valve plane. It was repaired with an extracardiac surgical approach, sparing the aortic root bioprosthesis previously implanted. The high-resolution three-dimensional details provided by the preoperative MDCT allowed us to plan a simple and effective surgical strategy.

  17. Treatment of iatrogenic V2 segment vertebral artery pseudoaneurysm using Pipeline flow-diverting stent

    PubMed Central

    Shakir, Hakeem J.; Rooney, Patrick J.; Rangel-Castilla, Leonardo; Yashar, Parham; Levy, Elad I.

    2016-01-01

    Background: Iatrogenic injury to the vertebral artery is a rare but potential complication of cervical spine surgery. Previous authors have commented on the use of flow-diverting stents for treatment of aneurysms of the V3 segment of the vertebral artery. Case Description: Here, we report a case in which injury occurred at the V2 segment of the vertebral artery with the development of a pseudoaneurysm, which was found on angiography. After decompressing the spinal cord from an epidural hematoma, the pseudoaneurysm was treated by deploying two Pipeline flow-diverting stents (Medtronic, Minneapolis, MN). Obliteration of the pseudoaneurysm was noted on follow-up angiography 4 days after the treatment. Conclusion: This case highlights a unique treatment at a region which, to our knowledge, has not been mentioned in the literature. PMID:28168090

  18. Flow-diverter stenting of post-traumatic bilateral anterior cerebral artery pseudoaneurysm: A case report

    PubMed Central

    Giorgianni, Andrea; Minotto, Renzo; Mercuri, Anna; Frattini, Lara; Baruzzi, Fabio; Valvassori, Luca

    2015-01-01

    The use of flow-diverter (FD) stents in recent years has positively changed the therapeutic approach to some vascular diseases, especially of certain types of aneurysms. This paper describes the case of a young patient after a major head trauma causing multiple skull fractures. The trauma occasioned two pseudoaneurysms from the A1 segment of the right anterior cerebral artery and from the A2 segment of the left anterior cerebral artery. Both lesions were treated with two Pipeline devices (ev3, Irvine, CA, USA) in two different sessions. The CT study and angiographic investigations performed in the following month showed a complete resolution of the post-traumatic pseudoaneurysmal lesions. Although the use of FD stents is described in the literature, particularly in the treatment of selected aneurysms, this paper shows good technical results in the use of these stents in cases of intracranial post-traumatic pseudoaneurysms with clinical improvement. PMID:25934771

  19. Endovascular Treatment of a Giant Superior Mesenteric Artery Pseudoaneurysm Using a Nitinol Stent-Graft

    SciTech Connect

    Gandini, Roberto; Pipitone, Vincenzo; Konda, Daniel Pendenza, Gianluca; Spinelli, Alessio; Stefanini, Matteo; Simonetti, Giovanni

    2005-01-15

    A 68-year-old woman presenting with gastrointestinal bleeding (hematocrit 19.3%) and in a critical clinical condition (American Society of Anesthesiologists grade 4) from a giant superior mesenteric artery pseudoaneurysm (196.0 x 131.4 mm) underwent emergency endovascular treatment. The arterial tear supplying the pseudoaneurysm was excluded using a 5.0 mm diameter and 31 mm long monorail expanded polytetrafluoroethylene (ePTFE)-covered self-expanding nitinol stent. Within 6 days of the procedure, a gradual increase in hemoglobin levels and a prompt improvement in the clinical condition were observed. Multislice CT angiograms performed immediately, 5 days, 30 days and 3 months after the procedure confirmed the complete exclusion of the pseudoaneurysm.

  20. Case-report: endovascular treatment of aortic pseudo-aneurysm caused by Fishbone.

    PubMed

    Wang, Wei; Liu, Xuesong; Lu, Mingjun

    2015-07-08

    Aortic pseudo-aneurysm (APA) is a rare disease in clinic. Because of its relative rarity, we are far from making any conclusion regarding the natural history and appropriate therapeutic strategy for this condition. This study is to investigate the treatment effect of interventional therapy in aortic pseudo-aneurysm. A woman of 68 years old diagnosed with APA caused by fishbone was treated with stent grafts. After treatment, the therapeutic effect was assessed by measuring the size of trauma. The patient recovered well after stent grafts treatment, as her trauma was minimal. However, some complications of intravascular interventional treatment were observed. Compared with conventional surgery, interventional therapy of intravascular stent grafts has its merits. Therefore, this strategy was worthy to apply in the treatment of aortic pseudo-aneurysm.

  1. Secondary organic aerosol formation from photo-oxidation of unburned fuel: experimental results and implications for aerosol formation from combustion emissions.

    PubMed

    Jathar, Shantanu H; Miracolo, Marissa A; Tkacik, Daniel S; Donahue, Neil M; Adams, Peter J; Robinson, Allen L

    2013-11-19

    We conducted photo-oxidation experiments in a smog chamber to investigate secondary organic aerosol (SOA) formation from eleven different unburned fuels: commercial gasoline, three types of jet fuel, and seven different diesel fuels. The goals were to investigate the influence of fuel composition on SOA formation and to compare SOA production from unburned fuel to that from diluted exhaust. The trends in SOA production were largely consistent with differences in carbon number and molecular structure of the fuel, i.e., fuels with higher carbon numbers and/or more aromatics formed more SOA than fuels with lower carbon numbers and/or substituted alkanes. However, SOA production from different diesel fuels did not depend strongly on aromatic content, highlighting the important contribution of large alkanes to SOA formation from mixtures of high carbon number (lower volatility) precursors. In comparison to diesels, SOA production from higher volatility fuels such as gasoline appeared to be more sensitive to aromatic content. On the basis of a comparison of SOA mass yields (SOA mass formed per mass of fuel reacted) and SOA composition (as measured by an aerosol mass spectrometer) from unburned fuels and diluted exhaust, unburned fuels may be reasonable surrogates for emissions from uncontrolled engines but not for emissions from engines with after treatment devices such as catalytic converters.

  2. Role of stabilized Criegee Intermediate in secondary organic aerosol formation from the ozonolysis of α-cedrene

    NASA Astrophysics Data System (ADS)

    Yao, Lei; Ma, Yan; Wang, Lin; Zheng, Jun; Khalizov, Alexei; Chen, Mindong; Zhou, Yaoyao; Qi, Lu; Cui, Fenping

    2014-09-01

    Atmospheric ozonolysis of sesquiterpenes is an important source of secondary organic aerosols (SOA). The mechanisms by which Criegee Intermediates (CIs) react to form SOA precursors and the influence of environmental conditions, however, remain unclear. On the basis of environmental chamber experiments coupled with detailed characterization of gas-phase and particle-phase products, we present evidence that a significant fraction of CIs from ozonolysis of α-cedrene are stabilized and bimolecular reactions of these stabilized CIs (SCIs) play a key role in the formation of SOA precursors. Ozonolysis experiments were conducted in a 4.5 m3 collapsible fluoropolymer chamber under various conditions in the presence of the OH radical and SCI scavengers. The size and mass of SOA particles produced during ozonolysis were measured directly and used for calculation of particle effective density and mass yield. Gaseous and particulate products were analyzed by several mass spectrometry methods. A total of 14 compounds in gas phase and 17 compounds in particle phase were tentatively identified. The major gas-phase products are secondary ozonides (SOZ) from intramolecular reactions of SCIs. Multifunctional organic acids are dominant particle-phase products. The measured density of aerosol particles is 1.04 ± 0.03 to 1.38 ± 0.03 g/cm3, and the aerosol mass yield is (23.7 ± 0.4)% to (46.4 ± 6.5)%, depending on reaction conditions. The presence of acetic acid, an SCI scavenger, inhibits new particle formation, but leads to increased aerosol mass yield. In contrast, the addition of SO2 dramatically enhances new particle formation and total aerosol yield. The calculated OH formation yield decreases from (62.4 ± 4.9)% to (9.0 ± 1.6)% upon addition of SCI scavengers CH3COOH and SO2, indicating that a large fraction of excited CIs are collisionally stabilized and unimolecular decomposition of SCIs via the hydroperoxide channel can be suppressed by bimolecular reactions. The

  3. The in vivo hydrocarbon formation by vanadium nitrogenase follows a secondary metabolic pathway

    PubMed Central

    Rebelein, Johannes G.; Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W.

    2016-01-01

    The vanadium (V)-nitrogenase of Azotobacter vinelandii catalyses the in vitro conversion of carbon monoxide (CO) to hydrocarbons. Here we show that an A. vinelandii strain expressing the V-nitrogenase is capable of in vivo reduction of CO to ethylene (C2H4), ethane (C2H6) and propane (C3H8). Moreover, we demonstrate that CO is not used as a carbon source for cell growth, being instead reduced to hydrocarbons in a secondary metabolic pathway. These findings suggest a possible role of the ancient nitrogenase as an evolutionary link between the carbon and nitrogen cycles on Earth and establish a solid foundation for biotechnological adaptation of a whole-cell approach to recycling carbon wastes into hydrocarbon products. Thus, this study has several repercussions for evolution-, environment- and energy-related areas. PMID:27976719

  4. Formation of secondary messengers by blood-formed elements in low-power laser irradiation

    NASA Astrophysics Data System (ADS)

    Brill, Gregory E.; Proshina, Olga V.; Zhigalina, Valentina N.; Filimonovskaya, Lyudmila S.; Romanova, Tatyana P.; Petrisheva, Svetlana G.; Zolotarjova, Tamara M.

    1995-05-01

    Irradiation of heparinized rat blood by He-Ne laser light ((lambda) - 632.8 nm, power density - 5 mW/cm2) during 15 or 30 min was performed in vitro experiments. The complex of biochemical parameters of erythrocytes, plasma and cytochemical parameters of polymorphonuclear leucocytes was studied. Laser irradiation was stated to cause different metabolic changes in red blood cells and neutrophils depending on the dose. In both doses of irradiation glucose-6-phosphate dehydrogenase activity lowers in erythrocytes, succinate dehydrogenase activity and lysosomal cationic proteins content increase in neutrophils. Stimulation of oxygen active forms production in cellular membranes of blood formed elements results in plasma malonic dialdehyde level increase and in the change of the balance between primary and secondary lipid peroxidation products. Cooperative interaction between different blood cells in the process of realization of system response to laser exposure is supposed to exist.

  5. Formation of beyerene, kaurene, trachylobane, and atiserene diterpenes by rearrangements that avoid secondary carbocations.

    PubMed

    Hong, Young J; Tantillo, Dean J

    2010-04-21

    Quantum chemical calculations on carbocation intermediates encountered during the conversion of ent-copalyl diphosphate to the diterpenes beyerene, kaurene, trachylobane, and atiserene are described. Based on the results of these computations, it is suggested that previously proposed secondary carbocation intermediates are avoided. In some cases, complex rearrangements in which up to three alkyl or hydride shifting events are coupled into concerted processes are predicted to occur instead. The potential effects of electron-rich active site groups on the inherent reactivity of key carbocations are discussed, as are complex rearrangements coupled to deprotonation events. Based on computed electrostatic potential maps, it also is proposed that ammonium ions that were previously designed as mimics of several carbocations are actually better mimics of transition state structures for carbocation deprotonation.

  6. Secondary natural gas recovery in mature fluvial sandstone reservoirs, Frio Formation, Agua Dulce Field, South Texas

    SciTech Connect

    Ambrose, W.A.; Levey, R.A. ); Vidal, J.M. ); Sippel, M.A. ); Ballard, J.R. ); Coover, D.M. Jr. ); Bloxsom, W.E. )

    1993-09-01

    An approach that integrates detailed geologic, engineering, and petrophysical analyses combined with improved well-log analytical techniques can be used by independent oil and gas companies of successful infield exploration in mature Gulf Coast fields that larger companies may consider uneconomic. In a secondary gas recovery project conducted by the Bureau of Economic Geology and funded by the Gas Research Institute and the U.S. Department of Energy, a potential incremental natural gas resource of 7.7 bcf, of which 4.0 bcf may be technically recoverable, was identified in a 490-ac lease in Agua Dulce field. Five wells in this lease had previously produced 13.7 bcf from Frio reservoirs at depths of 4600-6200 ft. The pay zones occur in heterogeneous fluvial sandstones offset by faults associated with the Vicksburg fault zone. The compartments may each contain up to 1.0 bcf of gas resources with estimates based on previous completions and the recent infield drilling experience of Pintas Creek Oil Company. Uncontacted gas resources occur in thin (typically less than 10 ft) bypassed zones that can be identified through a computed log evaluation that integrates open-hole logs, wireline pressure tests, fluid samples, and cores. At Agua Dulce field, such analysis identified at 4-ft bypassed zone uphole from previously produced reservoirs. This reservoir contained original reservoir pressure and flowed at rates exceeding 1 mmcf/d. The expected ultimate recovery is 0.4 bcf. Methodologies developed in the evaluation of Agua Dulce field can be successfully applied to other mature gas fields in the south Texas Gulf Coast. For example, Stratton and McFaddin are two fields in which the secondary gas recovery project has demonstrated the existence of thin, potentially bypassed zones that can yield significant incremental gas resources, extending the economic life of these fields.

  7. Aortic Branch Artery Pseudoaneurysms Associated with Intramural Hematoma: When and How to Do Endovascular Embolization

    SciTech Connect

    Ferro, Carlo; Rossi, Umberto G. Seitun, Sara; Scarano, Flavio; Passerone, Giancarlo; Williams, David M.

    2013-04-15

    To describe when and how to perform endovascular embolization of aortic branch artery pseudoaneurysms associated with type A and type B intramural hematoma (IMH) involving the descending thoracic and abdominal aorta (DeBakey I and III) that increased significantly in size during follow-up. Sixty-one patients (39 men; mean {+-} standard deviation age 66.1 {+-} 11.2 years) with acute IMH undergoing at least two multidetector computed tomographic examinations during follow-up for 12 months or longer were enrolled. Overall, 48 patients (31 men, age 65.9 {+-} 11.5) had type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III). Among the 48 patients, 26 (54 %; 17 men, aged 64.3 {+-} 11.4 years) had 71 aortic branch artery pseudoaneurysms. Overall, during a mean follow-up of 22.1 {+-} 9.5 months (range 12-42 months), 31 (44 %) pseudoaneurysms disappeared; 22 (31 %) decreased in size; two (3 %) remained stable; and 16 (22 %) increased in size. Among the 16 pseudoaneurysms with increasing size, five of these (three intercostal arteries, one combined intercostobronchial/intercostal arteries, one renal artery), present in five symptomatic patients, had a significant increase in size (thickness >10 mm; width and length >20 mm). These five patients underwent endovascular embolization with coils and/or Amplatzer Vascular Plug. In all patients, complete thrombosis and exclusion of aortic pseudoaneurysm and relief of back pain were achieved. Aortic branch artery pseudoaneurysms associated with type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III) may be considered relatively benign lesions. However, a small number may grow in size or extend longitudinally with clinical symptoms during follow-up, and in these cases, endovascular embolization can be an effective and safe procedure.

  8. Experimental investigation of cesium mobility in the course of secondary mineral formations in Hanford sediment columns at 50 degrees C.

    PubMed

    Mashal, Kholoud Y; Cetiner, Ziya S

    2010-10-01

    Formation of secondary minerals and Cs mobility in Hanford sediments were investigated under conditions similar to the Hanford tank leak in a dynamic flow system at 50 degrees C. The objectives were to (1) examine the nature and locations of secondary mineral phases precipitated in the sediments and (2) quantify the amount of Cs retained by the sediment matrix at 50 degrees C. To this end, Hanford sediments were packed into 10-cm long columns and leached with simulated tank waste consisting of 1.4 M NaOH, 0.125 M NaAlO(2), 3.7 M NaNO(3), and 1.3 x 10(-4) M Cs at 50 degrees C. Compositions of outflow solution were monitored with time for up to 25 days, and the columns were then segmented into four 2.5-cm long layers. The colloidal fraction in these segments was characterized in terms of mineralogy, particle morphology, Cs content, and short-range Al and Si structure. It was observed that cancrinite and sodalite precipitated at 50 degrees C. Approximately 53% Cs was retained in the column treated by the simulated tank waste at this temperature. Cesium retention in the column was lowered in the high ionic strength solution due to competition from Na for the exchange sites. This can be explained by alteration of distribution and number of sorption sites which reduces the selectivity of Cs for Na, and through the formation of cancrinite and sodalite. The formation of hydroxide complexes in highly alkaline solutions could also contribute to relatively poor retention of Cs by hindering ion exchange mechanism.

  9. Imaging diagnosis--celiac artery pseudoaneurysm associated with a migrating grass awn.

    PubMed

    Llabrés-Díaz, Francisco J; Brissot, Hervé; Ibarrola, Patricia

    2010-01-01

    The ultrasound and computed tomography findings of a retroperitoneal pseudoaneurysm associated with a grass awn are described in a 10-month-old dog. Ultrasound was used to localize the lesion and surrounding reaction as well as to determine its relationship with the celiac artery, but inadequate Doppler settings hindered the diagnosis of its vascular nature. Dual phase CT enabled further characterization, particularly its close relationship with the major retroperitoneal vessels. The imaging examination was fundamental in recommending nonsurgical therapy. The dog died as a consequence of the rupture of this pseudoaneurysm. A grass awn was confirmed.

  10. Compression assisted by removable coils as a new treatment for iatrogenic femoral pseudoaneurysms.

    PubMed

    Bellmunt, Sergi; Dilmé, Jaume; Barros, Antonio; Escudero, José Román

    2011-01-01

    To avoid undesirable effects that sometimes result from current treatments for postpuncture femoral pseudoaneurysms, we developed a new technique involving compression assisted by removable coils. Using ultrasound-guided percutaneous puncture, an Inconel coil with synthetic microfibers is inserted in the pseudoaneurysm, leaving a part of the coil above the skin. Short-duration, ultrasound-guided compression is applied, taking advantage of the coil's thrombogenicity. Following occlusion, the coil is removed, leaving no residual foreign material. The technique was effective in the first patient treated and may minimize or obviate the adverse effects associated with current approaches.

  11. Combined endovascular intervention and percutaneous thrombin injection in the treatment of iatrogenic pseudoaneurysm. Case report.

    PubMed

    Gabriel, M; Juszkat, R; Pukacki, F; Waliszewski, K

    2007-06-01

    One of the basic techniques of treatment of iatrogenic pseudoaneurysms is percutaneous thrombin injection. Unfortunately, success rate of this treatment can be limited in cases associated with extensive damage to arterial wall. Our paper presents one case of combined treatment involving endovascular occlusion of the entry to the false aneurysm and percutaneous thrombin injection into the pseudoaneurysm chamber. In our opinion this technique can be successfully applied in patients with contraindications for compression therapy, surgical intervention or failure of traditional injection due to large entry, multiple arterial wall damage or accompanying arteriovenous fistula.

  12. Transcatheter Embolization of Splenic Artery Pseudo-Aneurysm Rupturing into Colon After Post-Operative Pancreatitis

    SciTech Connect

    Iwama, Yuki; Sugimoto, Koji Zamora, Carlos A.; Yamaguchi, Masato; Tsurusaki, Masakatsu; Taniguchi, Takanori; Mori, Takeki; Sugimura, Kazuro

    2006-02-15

    Splenic pseudoaneurysms following chronic pancreatitis can rarely become a source of life-threatening bleeding by rupturing into various regions or components, including pseudocysts, the abdominal cavity, the gastrointestinal tract, and the pancreatic duct. In such cases, prompt diagnosis and therapy are warranted. We report herein the case of a 52-year-old man in whom a splenic pseudoaneurysm ruptured into the colon via a fistula with an abscess cavity, causing massive bleeding, which was successfully managed by trans-catheter arterial embolization (TAE)

  13. Superficial Temporal Artery Pseudoaneurysm: A Conservative Approach in a Critically Ill Patient

    SciTech Connect

    Grasso, Rosario Francesco Quattrocchi, Carlo Cosimo; Crucitti, Pierfilippo; Carboni, Giampiero; Coppola, Roberto; Zobel, Bruno Beomonte

    2007-04-15

    A 71-year-old man affected by cardio- and cerebrovascular disease experienced an accidental fall and trauma to the fronto-temporal area of the head. A few weeks later a growing mass appeared on his scalp. A diagnosis of superficial temporal artery pseudoaneurysm was made following CT and color Doppler ultrasound. His clinical condition favoured a conservative approach by ultrasound-guided compression and subsequent surgical resection. A conservative approach should be considered the treatment of choice in critically ill patients affected by superficial temporal artery pseudoaneurysm.

  14. Endoluminal Repair of a Dardik Prosthesis Pseudoaneurysm Using the Wallgraft Endoprosthesis

    SciTech Connect

    Zanchetta, Mario; Rigatelli, Gianluca; Konstantinos, Dimopoulos; Girardi, Diego; Caminiti, Antonio; Pedon, Luigi; Zennaro, Marco; Maiolino, Pietro

    2001-03-15

    A 58-year-old man with a history of severe invalidating claudicatio intermittens underwent femoropopliteal bypass with a human umbilical vein graft. Seven years later he presented with a painful enlarging mass in the middle portion of his right thigh. The duplex scan showed a pseudoaneurysm of the body of the prosthesis, which was confirmed by angiography. As an alternative to surgical management, Wallgraft endoprosthesis was used for endoluminal exclusion of the pseudoaneurysm. To our knowledge, this technique has never been used before in such a case.

  15. Stent-Graft Treatment for Bleeding Superior Mesenteric Artery Pseudoaneurysm After Pancreaticoduodenectomy

    SciTech Connect

    Suzuki, Kojiro Mori, Yoshine; Komada, Tomohiro; Matsushima, Masaya; Ota, Toyohiro; Naganawa, Shinji

    2009-07-15

    We report two cases of intraperitoneal bleeding from superior mesenteric artery (SMA) pseudoaneurysm after pancreaticoduodenectomy for pancreatic head carcinoma. In both cases, a stent-graft was deployed on the main SMA to exclude pseudoaneurysm and to preserve blood flow to the bowel. Bleeding stopped after the procedure. One patient was able to be discharged but died from carcinoma recurrence 4 months later. The other patient died of sepsis and stent-graft infection 5 months later. These patients remained free of intraperitoneal rebleeding during the follow-up period.

  16. Repair of Traumatic Abdominal Aortic Pseudoaneurysm Using N-Butyl-2-Cyano-Acrylate Embolization

    SciTech Connect

    Kawai, Nobuyuki; Sato, Morio Tanihata, Hirohiko; Sahara, Shinya; Takasaka, Isao; Minamiguchi, Hiroki; Nakai, Motoki

    2010-04-15

    Embolization using N-butyl-2-cyano-acrylate (NBCA) has been highly regarded for treating pseudoaneurysm, arteriovenous malformation, and hemorrhage of the visceral arteries. We report the case of a patient who fell from a cliff and sustained hemorrhagic shock with blunt abdominal aortic rupture and who underwent embolization using NBCA. This treatment achieved immediate hemostasis and stabilization of vital signs. Although the long-term durability of NBCA is unknown, it appears that certain types of acute aortic hemorrhage with narrow-necked pseudoaneurysm can be controlled by embolization using NBCA.

  17. Lower extremity vascular stenting for a post-traumatic pseudoaneurysm in a young trauma patient

    PubMed Central

    Marks, Joshua A; Hager, Eric; Henry, David; Martin, Niels D

    2011-01-01

    Endovascular treatment of post-traumatic pseudoaneurysms has become a viable, less invasive option when compared to open repair. Due to the relative youth of this technology, studies have yet to be concluded on the long-term patency of stent grafts in this population. For this reason, concern exists with endovascular stent placement in the young trauma patient. In this study, we present a case and review the literature on a post-traumatic pseudoaneurysm of the posterior tibial artery in a 19-year-old man treated with an endovascular stent. PMID:21769220

  18. Management of a Complicated Ruptured Infected Pseudoaneurysm of the Femoral Artery in a Drug Addict

    PubMed Central

    Psathas, Emmanouil; Lioudaki, Stella; Karantonis, Fotios-Filippos; Charalampoudis, Petros; Papadopoulos, Othon; Klonaris, Chris

    2012-01-01

    Infected pseudoaneurysm of the femoral artery represents a devastating complication of intravenous drug abuse, especially in the event of rupture. Operative strategy depends upon the extent of arterial injury and the coexistence of infection or sepsis. Options range from simple common femoral artery (CFA) ligation to complex arterial reconstruction with autologous grafts (arterial, venous, or homografts). We report herein the management of a 29-year-old male patient who was urgently admitted with a ruptured pseudoaneurysm of the right CFA, extending well above the inguinal ligament. Multidisciplinary approach with multiple arterial reconstructions and subsequent coverage of the tissue defect with a rectus abdominis musculocutaneous flap transposition was performed. PMID:23227421

  19. Pseudoaneurysm rupture after liver injury in a 14-year-old boy.

    PubMed

    Hacker, H W; Schwöbel, M G; Allgayer, B

    2008-04-01

    Today, haemodynamically stable children with blunt liver trauma are treated conservatively and can be discharged from hospital within one week. We report on a 14-year-old boy with a blunt hepatic trauma grade III, who showed a pseudoaneurysm with active bleeding into the abdominal cavity after mobilisation on day 9. Supraselective angiography of the right hepatic artery was performed and 2 titanium coils and gelatine sponge particles were placed for embolisation. In view of this complication, we suggest carrying out colour Doppler sonographic imaging to rule out pseudoaneurysm in children with blunt hepatic trauma before they are discharged from hospital.

  20. PET/CT imaging of abdominal aorta with intramural hematomas, penetrating ulcer, and saccular pseudoaneurysm.

    PubMed

    Nguyen, Vien X; Nguyen, Ba D

    2014-05-01

    Acute aortic syndromes, encompassing intramural hematoma, penetrating ulcer, and pseudoaneurysm, are best demonstrated by angiographic CT and magnetic resonance imaging. These imaging modalities provide an accurate evaluation and allow timely therapies of these frequently symptomatic lesions, thus reducing their morbidity and mortality. The inflammatory pathogenesis of these acute aortic syndromes may exhibit positive PET findings predictive of prognosis and outcomes of these vascular events. The authors present a case of PET/CT imaging showing asymptomatic intramural hematomas with penetrating ulcer and saccular pseudoaneurysm of the proximal abdominal aorta.

  1. Ruptured Mycotic Pulmonary Artery Pseudoaneurysm in an Infant: Transcatheter Embolization and CT Assessment

    SciTech Connect

    Deshmukh, Hemant; Rathod, Krantikumar; Garg, Ashwin Sheth, Rahul

    2003-09-15

    Mycotic pseudoaneurysm of the pulmonary artery that ruptures during necrotizing pneumonia is a rare entity that is often fatal. Traditionally it has been treated with open thoracotomy and resection of both the aneurysm and the lobe in which the aneurysm is located. In this report, we describe the radiological findings and transcatheter coil embolization of a mycotic pulmonary pseudoaneurysm in a 6-month-old female infant. We also describe the subsequent morphologic changes observed on follow-up computed tomography after 9 months of embolization.

  2. Endovascular treatment of a symptomatic vertebral artery pseudoaneurysm.

    PubMed

    Inaraja Pérez, Gabriel Cristian; Rodríguez Morata, Alejandro; Reyes Ortega, Juan Pedro; Gómez Medialdea, Rafael; Cabezudo García, Pablo

    2015-07-01

    A 35-year-old patient was brought to the emergency department referring dysarthria, left ear tinnitus for 5 min, and short-lasting blindness, with headache in the 45 min before the clinical presentation. In the magnetic resonance imaging, an acute-subacute lesion in the cerebellum right-anterior lobe (in the territory of the cerebellum anterior artery) and a dilatation near the ostium of the right vertebral artery were seen. For a better assessment, an Angio-CT was done, showing a 9-mm saccular pseudoaneurysm of the right vertebral artery close to the origin of the vessel, without being able to determine if it had been caused because of a dissection. The rest of the study (cerebral vessels and supra-aortic vessels) showed no disorders. He was operated under local anesthesia and sedation a week after the onset of the symptoms. Through a 0.014 wire, a Biotronik PK Papyrus balloon-expandable covered cobalt-chromium stent was deployed covering the hole in the artery. Antiplatelet drugs were prescribed, and the patient was discharged 24 hr after surgery. He has remained symptom free since then.

  3. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: Explicit modeling of SOA formation from alkane and alkene oxidation

    SciTech Connect

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2016-02-08

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. Furthermore, this work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.

  4. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: Explicit modeling of SOA formation from alkane and alkene oxidation

    DOE PAGES

    La, Y. S.; Camredon, M.; Ziemann, P. J.; ...

    2016-02-08

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chambermore » experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. Furthermore, this work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.« less

  5. Insights into secondary organic aerosol formation mechanisms from measured gas/particle partitioning of specific organic tracer compounds.

    PubMed

    Zhao, Yunliang; Kreisberg, Nathan M; Worton, David R; Isaacman, Gabriel; Weber, Robin J; Liu, Shang; Day, Douglas A; Russell, Lynn M; Markovic, Milos Z; VandenBoer, Trevor C; Murphy, Jennifer G; Hering, Susanne V; Goldstein, Allen H

    2013-04-16

    In situ measurements of organic compounds in both gas and particle phases were made with a thermal desorption aerosol gas chromatography (TAG) instrument. The gas/particle partitioning of phthalic acid, pinonaldehyde, and 6,10,14-trimethyl-2-pentadecanone is discussed in detail to explore secondary organic aerosol (SOA) formation mechanisms. Measured fractions in the particle phase (f(part)) of 6,10,14-trimethyl-2-pentadecanone were similar to those expected from the absorptive gas/particle partitioning theory, suggesting that its partitioning is dominated by absorption processes. However, f(part) of phthalic acid and pinonaldehyde were substantially higher than predicted. The formation of low-volatility products from reactions of phthalic acid with ammonia is proposed as one possible mechanism to explain the high f(part) of phthalic acid. The observations of particle-phase pinonaldehyde when inorganic acids were fully neutralized indicate that inorganic acids are not required for the occurrence of reactive uptake of pinonaldehyde on particles. The observed relationship between f(part) of pinonaldehyde and relative humidity suggests that the aerosol water plays a significant role in the formation of particle-phase pinonaldehyde. Our results clearly show it is necessary to include multiple gas/particle partitioning pathways in models to predict SOA and multiple SOA tracers in source apportionment models to reconstruct SOA.

  6. Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Kacarab, M.; Li, L.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Two surrogate reactive organic gas (ROG) mixtures were developed to create a controlled reactivity environment simulating different urban atmospheres with varying levels of anthropogenic (e.g. Los Angeles reactivity) and biogenic (e.g. Atlanta reactivity) influences. Traditional chamber experiments focus on the oxidation of one or two volatile organic compound (VOC) precursors, allowing the reactivity of the system to be dictated by those compounds. Surrogate ROG mixtures control the overall reactivity of the system, allowing for the incremental aerosol formation from an added VOC to be observed. The surrogate ROG mixtures were developed based on that used to determine maximum incremental reactivity (MIR) scales for O3 formation from VOC precursors in a Los Angeles smog environment. Environmental chamber experiments were designed to highlight the incremental aerosol formation in the simulated environment due to the addition of an added anthropogenic (aromatic) or biogenic (terpene) VOC. All experiments were conducted in the UC Riverside/CE-CERT dual 90m3 environmental chambers. It was found that the aerosol precursors behaved differently under the two altered reactivity conditions, with more incremental aerosol being formed in the anthropogenic ROG system than in the biogenic ROG system. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Data will be presented on aerosol properties (density, volatility, hygroscopicity) and bulk chemical composition in the gas and particle phases (from a SYFT Technologies selected ion flow tube mass spectrometer, SIFT-MS, and Aerodyne high resolution time of flight aerosol mass spectrometer, HR-ToF-AMS, respectively) comparing the two controlled reactivity systems and single precursor VOC/NOx studies. Incremental aerosol yield data at different controlled reactivities provide a novel and valuable insight in the attempt to extrapolate environmental chamber

  7. Secondary structure formation and LCST behavior of short elastin-like peptides.

    PubMed

    Nuhn, Harald; Klok, Harm-Anton

    2008-10-01

    This contribution investigates the effects of chain length and chemical composition on the secondary structure and LCST behavior of a library of short, elastin-like peptides based on the GVGVP motif. CD experiments revealed that most of the investigated peptides showed the typical elastin conformational behavior with a decrease in random coil and an increase in beta-turn character with increasing temperature. For several peptides, LCST behavior was observed in aqueous NaCl solutions containing 10 mg/mL peptide. By extrapolation of the LCSTs measured at different NaCl concentrations to zero-salt concentration, apparent LCSTs were determined. The apparent LCST was found to decrease with increasing peptide chain length, which correlated well with the trend in the predicted partition coefficients. The apparent LCST of the peptides could be manipulated by successive replacement of the valine residues by more hydrophobic isoleucine, leucine, or phenylalanine residues. Within a particular series of variants, the apparent LCST was found to decrease with an increasing number of valine replacements, which also correlated well with the predicted evolution of the partition coefficient. Although the relative importance of the overall peptide hydrophobicity and the conformational preferences of the constituent amino acids on the LCST behavior still remains an open question, the results described in this contribution clearly demonstrate that short, elastin-like peptides are potentially attractive building blocks for a range of materials applications in biomedicine and engineering.

  8. The plant secondary metabolite citral alters water status and prevents seed formation in Arabidopsis thaliana.

    PubMed

    Graña, E; Díaz-Tielas, C; López-González, D; Martínez-Peñalver, A; Reigosa, M J; Sánchez-Moreiras, A M

    2016-05-01

    Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 μm citral showed decreased RWC, reduced Ψs , increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil.

  9. Secondary caries formation in vitro around glass ionomer-lined amalgam and composite restorations.

    PubMed

    Dionysopoulos, P; Kotsanos, N; Papadogianis, Y

    1996-08-01

    The aim of this in vitro secondary caries study was to examine the glass-ionomer liner's effect on wall-lesion inhibition when a conventional and a light-cured glass ionomer liner was placed under amalgam and composite resin restorations. Class V preparations in extracted upper premolars were used and ten restorations were used for each of the following groups: (i) two layers of copal varnish and amalgam; (ii) conventional glass-ionomer and amalgam; (iii) light-cured glass-ionomer and amalgam; (iv) bonding agent and light-cured composite resin; (v) conventional glass-ionomer, bonding agent and light-cured composite resin; (vi) light-cured glass-ionomer, extended 0.3 mm short of the enamel margin bonding agent and light-cured composite resin; and (vii) light-cured glass-ionomer, extended 1 mm short of the enamel margin, bonding agent and light-cured composite resin. The teeth were thermocycled and artificial caries were created using an acid-gel. The results of this study showed that artificial recurrent caries can be reduced significantly (P < 0.05) with a glass-ionomer liner under amalgam restorations. The results also showed that when the light-cured glass-ionomer liner was placed 0.3 mm from the cavosurface margin under composite resin restoration, the artificial recurrent caries reduced significantly (P < 0.05).

  10. Secondary Organic Aerosol Formation and Organic Nitrate Yield from NO3 Oxidation of Biogenic Hydrocarbons

    PubMed Central

    2014-01-01

    The secondary organic aerosol (SOA) mass yields from NO3 oxidation of a series of biogenic volatile organic compounds (BVOCs), consisting of five monoterpenes and one sesquiterpene (α-pinene, β-pinene, Δ-3-carene, limonene, sabinene, and β-caryophyllene), were investigated in a series of continuous flow experiments in a 10 m3 indoor Teflon chamber. By making in situ measurements of the nitrate radical and employing a kinetics box model, we generate time-dependent yield curves as a function of reacted BVOC. SOA yields varied dramatically among the different BVOCs, from zero for α-pinene to 38–65% for Δ-3-carene and 86% for β-caryophyllene at mass loading of 10 μg m–3, suggesting that model mechanisms that treat all NO3 + monoterpene reactions equally will lead to errors in predicted SOA depending on each location’s mix of BVOC emissions. In most cases, organonitrate is a dominant component of the aerosol produced, but in the case of α-pinene, little organonitrate and no aerosol is formed. PMID:25229208

  11. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    NASA Astrophysics Data System (ADS)

    Malloy, Q. G. J.; Qi, Li; Warren, B.; Cocker, D. R., III; Erupe, M. E.; Silva, P. J.

    2008-07-01

    Primary aliphatic amines are an important class of nitrogen containing compounds found to be emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with NO3 has been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by extension NO3, large yields of aerosol mass loadings (~44% for butylamine) are seen. Aerosol generated was determined to be organic in nature due to the small fraction of NO and NO2 in the total signal (<17% for all amines tested) as detected by an aerosol mass spectrometer (AMS). We propose a reaction mechanism between carbonyl containing species and the parent amine leading to formation of particulate imine products. These findings can have significant impacts on rural communities and lead to elevated nighttime PM loadings, when significant levels on NO3 exist.

  12. Secondary organic aerosol formation from primary aliphatic amines with NO3 radical

    NASA Astrophysics Data System (ADS)

    Malloy, Q. G. J.; Qi, Li; Warren, B.; Cocker, D. R., III; Erupe, M. E.; Silva, P. J.

    2009-03-01

    Primary aliphatic amines are an important class of nitrogen containing compounds emitted from automobiles, waste treatment facilities and agricultural animal operations. A series of experiments conducted at the UC-Riverside/CE-CERT Environmental Chamber is presented in which oxidation of methylamine, ethylamine, propylamine, and butylamine with O3 and NO3 have been investigated. Very little aerosol formation is observed in the presence of O3 only. However, after addition of NO, and by extension NO3, large aerosol mass yields (~44% for butylamine) are seen. Aerosol generated was determined to be organic in nature due to the small fraction of NO and NO2 in the total signal (<1% for all amines tested) as detected by an aerosol mass spectrometer (AMS). We propose a reaction mechanism between carbonyl containing species and the parent amine leading to formation of particulate imine products. These findings can have significant impacts on rural communities with elevated nighttime PM loadings, when significant levels of NO3 exist.

  13. Postpartum Hemorrhage Resulting from Pelvic Pseudoaneurysm: A Retrospective Analysis of 588 Consecutive Cases Treated by Arterial Embolization

    SciTech Connect

    Dohan, Anthony Soyer, Philippe Subhani, Aqeel; Hequet, Delphine; Fargeaudou, Yann; Morel, Olivier; Boudiaf, Mourad; Gayat, Etienne; Barranger, Emmanuel; Dref, Olivier Le Sirol, Marc

    2013-10-15

    Objective: This study was designed to determine the incidence of arterial pseudoaneurysm in patients presenting with postpartum hemorrhage (PPH), to analyze the angiographic characteristics of pseudoaneurysms that cause PPH, and to evaluate the effectiveness of pelvic arterial embolization for the treatment of this condition.Study designEighteen women with pelvic arterial pseudoaneurysm were retrieved from a series of 588 consecutive patients with PPH treated by arterial embolization. Clinical files, angiographic examinations, and procedure details were reviewed. Results: The incidence of pseudoaneurysm was 3.06 % (18/588; 95 % confidence interval (CI): 1.82-4.8 %). A total of 20 pseudoaneurysms were found; 15/20 (75 %) were located on the uterine arteries. Angiography revealed extravasation of contrast material from pseudoaneurysm indicating rupture in 9 of 18 (50 %) patients. Arterial embolization was performed using gelatin sponge alone in 12 of 18 (67 %) patients or in association with metallic coils in 5 of 18 (28 %) patients or n-butyl-2-cyanoacrylate in 1 of 18 (6 %) patients. Arterial embolization allowed controlling the bleeding in all patients after one or two embolization sessions in 17 of 18 (94 %) and 1 of 18 patients (6 %) respectively, without complications, obviating the need for further surgery. Conclusions: Pseudoaneurysm is rarely associated with PPH. Arterial embolization is an effective and safe procedure for the treatment of PPH due to uterine or vaginal artery pseudoaneurysm. Our results suggest that gelatin sponge is effective for the treatment of ruptured pseudoaneurysms, although we agree that our series does not contain sufficient material to allow drawing definitive conclusions with respect to the most effective embolic material.

  14. Patterns of growth and tract formation during the early development of secondary lineages in the Drosophila larval brain.

    PubMed

    Lovick, Jennifer K; Kong, Angel; Omoto, Jaison J; Ngo, Kathy T; Younossi-Hartenstein, Amelia; Hartenstein, Volker

    2016-04-01

    The Drosophila brain consists of a relatively small number of invariant, genetically determined lineages which provide a model to study the relationship between gene function and neuronal architecture. In following this long-term goal, we reconstruct the morphology (projection pattern and connectivity) and gene expression patterns of brain lineages throughout development. In this article, we focus on the secondary phase of lineage morphogenesis, from the reactivation of neuroblast proliferation in the first larval instar to the time when proliferation ends and secondary axon tracts have fully extended in the late third larval instar. We have reconstructed the location and projection of secondary lineages at close (4 h) intervals and produced a detailed map in the form of confocal z-projections and digital three-dimensional models of all lineages at successive larval stages. Based on these reconstructions, we could compare the spatio-temporal pattern of axon formation and morphogenetic movements of different lineages in normal brain development. In addition to wild type, we reconstructed lineage morphology in two mutant conditions. (1) Expressing the construct UAS-p35 which rescues programmed cell death we could systematically determine which lineages normally lose hemilineages to apoptosis. (2) so-Gal4-driven expression of dominant-negative EGFR ablated the optic lobe, which allowed us to conclude that the global centrifugal movement normally affecting the cell bodies of lateral lineages in the late larva is causally related to the expansion of the optic lobe, and that the central pattern of axonal projections of these lineages is independent of the presence or absence of the optic lobe.

  15. Patterns of growth and tract formation during the early development of secondary lineages in the Drosophila larval brain

    PubMed Central

    Lovick, Jennifer K.; Kong, Angel; Omoto, Jaison J.; Ngo, Kathy T.; Younossi-Hartenstein, Amelia; Hartenstein, Volker

    2015-01-01

    The Drosophila brain consists of a relatively small number of invariant, genetically determined lineages which provide a model to study the relationship between gene function and neuronal architecture. In following this long-term goal we reconstruct the morphology (projection pattern and connectivity) and gene expression patterns of brain lineages throughout development. In the present paper, we focus on the secondary phase of lineage morphogenesis, from the reactivation of neuroblast proliferation in the first larval instar to the time when proliferation ends and secondary axon tracts have fully extended in the late third larval instar. We have reconstructed the location and projection of secondary lineages at close (4h) intervals and produced a detailed map in the form of confocal z-projections and digital 3D models of all lineages at successive larval stages. Based on these reconstructions we could compare the spatio-temporal pattern of axon formation and morphogenetic movements of different lineages in normal brain development. In addition to wild type, we reconstructed lineage morphology in two mutant conditions. (1) Expressing the construct UAS-p35 which rescues programmed cell death we could systematically determine which lineages normally lose hemilineages to apoptosis. (2) so-Gal4-driven expression of dominant-negative EGFR ablated the optic lobe, which allowed us to conclude that the global centrifugal movement normally affecting the cell bodies of lateral lineages in the late larva is causally related to the expansion of the optic lobe, and that the central pattern of axonal projections of these lineages is independent of the presence or absence of the optic lobe. PMID:26178322

  16. Formation and chemical aging of secondary organic aerosol during the β-caryophyllene oxidation

    NASA Astrophysics Data System (ADS)

    Tasoglou, A.; Pandis, S. N.

    2015-06-01

    The secondary organic aerosol (SOA) production during the oxidation of β-caryophyllene by ozone (O3) and hydroxyl radicals (OH) and the subsequent chemical aging of the products during reactions with OH were investigated. Experiments were conducted with ozone and with hydroxyl radicals at low NOx (zero added NOx) and at high NOx (hundreds of parts per billion). The SOA mass yield at 10 μg m-3 of organic aerosol was 27% for the ozonolysis, 20% for the reaction with OH at low NOx, and 38% at high NOx under dry conditions, 20 °C, and ozone excess. Parameterizations of the fresh SOA yields have been developed. The average fresh SOA atomic O : C ratio varied from 0.24 to 0.34 depending on the oxidant and the NOx level, while the H : C ratio was close to 1.5 for all systems examined. An average density of 1.06 ± 0.1 μg m-3 of the β-caryophyllene SOA was estimated. The exposure to UV light had no effect on the β-caryophyllene SOA concentration and aerosol mass spectrometer (AMS) measurements. The chemical aging of the β-caryophyllene SOA produced was studied by exposing the fresh SOA to high concentrations (107 molecules cm-3) of OH for several hours. These additional reactions increased the SOA concentration by 15-40% and O : C by approximately 25%. A limited number of experiments suggested that there was a significant impact of the relative humidity on the chemical aging of the SOA. The evaporation rates of β-caryophyllene SOA were quantified by using a thermodenuder allowing us to estimate the corresponding volatility distributions and effective vaporization enthalpies.

  17. The formation of secondary organic aerosol from the isoprene + OH reaction in the absence of NOx

    NASA Astrophysics Data System (ADS)

    Kleindienst, T. E.; Lewandowski, M.; Offenberg, J. H.; Jaoui, M.; Edney, E. O.

    2009-09-01

    The reaction of isoprene (C5H8) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (ΔHvapeff), organic peroxide fraction, and the aerosol yield. The gas phase analysis showed the presence of methacrolein, methyl vinyl ketone, and four isomers of the methyl butenediols. These gas-phase compounds may serve as precursors for one or more of several compounds detected in the aerosol phase including 2-methylglyceric acid, three 2-methyl alkenetriols, and two 2-methyl tetrols. In contrast to most previous studies, the 2-methyl tetrols (and the 2-methyl alkenetriols) were found to form in the absence of acidic sulfate aerosol. However, reaction conditions did not favor the production of HO2 radicals, thus allowing RO2+RO2 reactions to proceed more readily than if higher HO2 levels had been generated. SOA/SOC (i.e. OM/OC) was found to average 1.9 in the absence of NOx. The effective enthalpy of vaporization was measured as 38.6 kJ mol-1, consistent with values used previously in modeling studies. The yields in this work (using an independent technique than used previously) are lower than those of Kroll et al. (2006) for similar aerosol masses. SOC yields reported in this work range from 0.5-1.4% for carbon masses between 17 and 49 μgC m-3.

  18. The formation of secondary organic aerosol from the isoprene + OH reaction in the absence of NOx

    NASA Astrophysics Data System (ADS)

    Kleindienst, T. E.; Lewandowski, M.; Offenberg, J. H.; Jaoui, M.; Edney, E. O.

    2009-04-01

    The reaction of isoprene (C5H8) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (ΔHvapeff), the organic peroxide fraction, and the aerosol yield. The gas phase analysis showed the presence of methacrolein, methyl vinyl ketone, and four isomers of the methyl butenediols. These gas-phase compounds may serve as precursors for one or more of several compounds detected in the aerosol phase including 2-methylglyceric acid, three 2-methyl alkenetriols, and two 2-methyl tetrols. In contrast to most previous studies, the 2-methyl tetrols (and the 2-methyl alkenetriols) were found to form in the absence of acidic sulfate aerosol. A re-evaluation of field samples in Research Triangle Park, North Carolina, during the summers of 2000 and 2001 indicated in the presence of the methyl butenediols from gas-phase denuder samples taken at the time. SOA/SOC (i.e., OM/OC) was found to average 1.9 in the absence of NOx. The effective enthalpy of vaporization was measured as 38.6 kJ mol-1, consistent with values that have previously been used in modeling studies. The yields in this work (using an independent technique than that previous) are lower than those of Kroll et al. (2006) for similar aerosol masses. SOC yields reported in this work range from 0.5-1.4% for carbon masses between 17 and 49 μgC m-3.

  19. Role of toxic and bioactive secondary metabolites in colonization and bloom formation by filamentous cyanobacteria Planktothrix.

    PubMed

    Kurmayer, Rainer; Deng, Li; Entfellner, Elisabeth

    2016-04-01

    Bloom-forming cyanobacteria Planktothrix agardhii and P. rubescens are regularly involved in the occurrence of cyanotoxin in lakes and reservoirs. Besides microcystins (MCs), which inhibit eukaryotic protein phosphatase 1 and 2A, several families of bioactive peptides are produced, thereby resulting in impressive secondary metabolite structural diversity. This review will focus on the current knowledge of the phylogeny, morphology, and ecophysiological adaptations of Planktothrix as well as the toxins and bioactive peptides produced. The relatively well studied ecophysiological adaptations (buoyancy, shade tolerance, nutrient storage capacity) can partly explain the invasiveness of this group of cyanobacteria that bloom within short periods (weeks to months). The more recent elucidation of the genetic basis of toxin and bioactive peptide synthesis paved the way for investigating its regulation both in the laboratory using cell cultures as well as under field conditions. The high frequency of several toxin and bioactive peptide synthesis genes observed within P. agardhii and P. rubescens, but not for other Planktothrix species (e.g. P. pseudagardhii), suggests a potential functional linkage between bioactive peptide production and the colonization potential and possible dominance in habitats. It is hypothesized that, through toxin and bioactive peptide production, Planktothrix act as a niche constructor at the ecosystem scale, possibly resulting in an even higher ability to monopolize resources, positive feedback loops, and resilience under stable environmental conditions. Thus, refocusing harmful algal bloom management by integrating ecological and phylogenetic factors acting on toxin and bioactive peptide synthesis gene distribution and concentrations could increase the predictability of the risks originating from Planktothrix blooms.

  20. The SOA formation model combined with semiempirical quantum chemistry for predicting UV-Vis absorption of secondary organic aerosols.

    PubMed

    Zhong, Min; Jang, Myoseon; Oliferenko, Alexander; Pillai, Girinath G; Katritzky, Alan R

    2012-07-07

    A new model for predicting the UV-visible absorption spectra of secondary organic aerosols (SOA) has been developed. The model consists of two primary parts: a SOA formation model and a semiempirical quantum chemistry method. The mass of SOA is predicted using the PHRCSOA (Partitioning Heterogeneous Reaction Consortium Secondary Organic Aerosol) model developed by Cao and Jang [Environ. Sci. Technol., 2010, 44, 727]. The chemical composition is estimated using a combination of the kinetic model (MCM) and the PHRCSOA model. The absorption spectrum is obtained by taking the sum of the spectrum of each SOA product calculated using a semiempirical NDDO (Neglect of Diatomic Differential Overlap)-based method. SOA was generated from the photochemical reaction of toluene or α-pinene at different NO(x) levels (low NO(x): 24-26 ppm, middle NO(x): 49 ppb, high NO(x): 104-105 ppb) using a 2 m(3) indoor Teflon film chamber. The model simulation reasonably agrees with the measured absorption spectra of α-pinene SOA but underestimates toluene SOA under high and middle NO(x) conditions. The absorption spectrum of toluene SOA is moderately enhanced with increasing NO(x) concentrations, while that of α-pinene SOA is not affected. Both measured and calculated UV-visible spectra show that the light absorption of toluene SOA is much stronger than that of α-pinene SOA.

  1. Characterization of new particle and secondary aerosol formation during summertime in Beijing, China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Zhang, X. Y.; Sun, J. Y.; Lin, W. L.; Gong, S. L.; Shen, X. J.; Yang, S.

    2011-07-01

    Size-resolved aerosol number and mass concentrations and the mixing ratios of O3 and various trace gases were continuously measured at an urban station before and during the Beijing Olympic and Paralympic Games (5 June to 22 September, 2008). 23 new particle formation (NPF) events were identified; these usually were associated with changes in wind direction and/or rising concentrations of gas-phase precursors or after precipitation events. Most of the NPF events started in the morning and continued to noon as particles in the nucleation mode grew into the Aitken mode. From noon to midnight, the aerosols grew into the accumulation mode through condensation and coagulation. Ozone showed a gradual rise starting around 10:00 local time, reached its peak around 15:00 and then declined as the organics increased. The dominant new particle species were organics (40-75% of PM1) and sulphate; nitrate and ammonium were more minor contributors.

  2. Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection.

    PubMed

    Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling

    2016-01-01

    Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for

  3. Substantial secondary organic aerosol formation in a coniferous forest: observations of both day and night time chemistry

    NASA Astrophysics Data System (ADS)

    Lee, A. K. Y.; Abbatt, J. P. D.; Leaitch, W. R.; Li, S.-M.; Sjostedt, S. J.; Wentzell, J. J. B.; Liggio, J.; Macdonald, A. M.

    2015-10-01

    Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region at Whistler, British Columbia. A largely biogenic aerosol growth episode was observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas-particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 will arise from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by the OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22-33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol, and so f91 is used as an indicator of BSOA formation pathways. A comparison between laboratory studies in the literature and our field observations highlights the potential importance of gas-phase formation chemistry of BSOA-2 type materials that may not be captured in smog chamber experiments, perhaps due to the wall loss of gas-phase intermediate products.

  4. Traumatic Pseudoaneurysm Related to Calcified Nodules of Cerebral Convexity Dura Mater in an American College Football Player

    PubMed Central

    Jeon, Yoo Sung; Lee, Jong Gon; Cho, Joon; Choe, Woo Jin

    2016-01-01

    Repeated concussion is common among football players; however, these minor blunt head trauma rarely result in serious complications. We report a case of a young college football player who presented acute subdural hematoma, cerebral edema, and seizure due to pseudoaneurysm rupture. The pseudoaneurysm, located at the cortical branch of the middle cerebral artery, was speculated to be formed by dural calcification and adhesion with the underlying brain, possibly due to repeated concussions. Following successful excision of the pseudoaneurysm and control of brain swelling, the patient recovered without sequelae and was discharged after a short while. PMID:27847782

  5. Reactive Uptake of Ammonia to Secondary Organic Aerosols: Kinetics of Organonitrogen Formation

    NASA Astrophysics Data System (ADS)

    Liu, Yongchun; Liggio, John; Staebler, Ralf; Li, Shao-Meng

    2015-04-01

    Organonitrogen compounds originating from the heterogeneous uptake of NH3 or amines by secondary organic aerosol (SOA) has received significant attention recently. This is primarily due to its potential contribution to brown carbon (BrC), which can absorb solar radiation and affect climate. In addition, particle phase Organonitrogen species may represent a means of altering regional nitrogen cycles and/or nitrogen deposition patterns though the sequestering of ambient ammonia which is ultimately deposited downwind. Several reduced nitrogen forming heterogeneous reactions have previously been proposed, including Schiff base and/or Mannich reactions between NH3, ammonium salts or amines and organic carbonyl functional groups in particles. In order to assess and model the possible impact of Schiff base, Mannich or other N-forming reactions (via NH3) on the radiative forcing ability of ambient SOA and/or its impact on N-deposition, the kinetics of such heterogeneous reactions are required, and yet remain largely unknown. In the current study, the uptake kinetics of NH3 to form organonitrogen compounds in SOA derived from the ozonolysis of α-pinene and the OH oxidation of m-xylene is reported for the first time from experiments performed in a 9 m3 smog chamber equipped with a High Resolution Time-of-Flight Aerosol Mass Spectrometer. The results demonstrate that particle bound organonitrogen compounds are mainly formed by NH3 uptake onto newly formed SOA (~1 hr), but relatively little onto more aged SOA. The uptake coefficients of NH3 to form organonitrogen compounds (between 0-150 min) are on the order of 10-4-10-3 and are prominently dependent upon particle acidity. Following 6 hours of reaction, the total organonitrogen mass contributed up to 10.0±1.5 wt% and 31.5±4.4 wt% to the total SOA mass from the ozonolysis of α-pinene and OH oxidation of m-xylene. The influence of VOC precursors, seed particle acidity and gaseous NH3 concentration on the obtained uptake

  6. Secondary Organic Aerosol Formation and Aging in a Flow Reactor in the Forested Southeast US during SOAS

    NASA Astrophysics Data System (ADS)

    Hu, W.; Palm, B. B.; Hacker, L.; Campuzano Jost, P.; Day, D. A.; Simoes de Sa, S.; Fry, J.; Ayres, B. R.; Draper, D. C.; Ortega, A. M.; Kiendler-Scharr, A.; Panujoka, A.; Virtanen, A.; Miettinen, P.; Krechmer, J.; Canagaratna, M. R.; Thompson, S.; Yatavelli, L. R.; Stark, H.; Worsnop, D. R.; Lechner, M.; Martin, S. T.; Farmer, D.; Brown, S. S.; Jimenez, J. L.

    2013-12-01

    A major field campaign (Southern Oxidant and Aerosol Study, SOAS) was conducted in summer 2013 in a forested area (Centreville Supersite) in the southeast U.S. To investigate secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (BVOCs), 3 flow reactors (potential aerosol mass, PAM) were used to expose ambient air to oxidants and their output was analyzed by state-of-art gas and aerosol instruments including a High-Resolution Aerosol Mass Spectrometer (HR-AMS), a High-Resolution Proton-Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOFMS), and for the first time, two different High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometers (HRToF-CIMS), and an SMPS. Ambient air was exposed 24/7 to variable concentrations of each of the 3 main atmospheric oxidants (OH, O3 and NO3) to investigate SOA formation and aging. The OH exposure was estimated by 3 different methods (empirical parameterization, carbon monoxide consumption, and chemical box model). Effective OH exposures up to 7e12 molec cm-3 s were achieved, which is equivalent to over a month of aging in the atmosphere. High SOA formation of up to 12 μg m-3 above ambient concentrations of 5 μg m-3 was observed under intermediate OH exposures, while very high OH exposures led to destruction of ambient OA by ≈ 30%, indicating shifting contributions of functionalization vs. fragmentation, which is similar to previous results from urban and terpene-dominated environments. The highest SOA enhancements were 3-4 times higher than the ambient OA. More SOA is typically formed during nighttime when terpenes are higher and lower during daytime when isoprene is higher. SOA formation is also observed after exposure of ambient air to O3 or NO3, although the amount and oxidation was lower than for OH exposure. Formation of organic nitrates in the NO3 reaction will be discussed. High SOA formation (above 40 μg m-3) and a large number of CIMS ions, indicating many different

  7. Reactive Uptake of Ammonia and Formation of Organic Nitrogen Species for Non-Liquid/Liquid Secondary Organic Material

    NASA Astrophysics Data System (ADS)

    Martin, S. T.; Li, Y.; Liu, P.

    2015-12-01

    Formation of ammonium and organic nitrogen (ON) species was studied for secondary organic material (SOM) of variable viscosity, ranging from non-liquid to liquid physical states. The SOM was produced as particles of 50 to 150 nm in diameter in aerosol form from six precursors, including three terpenoid and three aromatic species. The viscosity of the hygroscopic SOM was adjusted by exposure to relative humidity (RH) from <5% to >90% RH in steps of 10% at 293 ± 2 K. The aerosol was subsequently exposed to 5 ppm NH3 for mean reaction times of 30, 370, or 5230 s. Ammonium and ON were characterized by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS). The ammonium-to-organic ratio of mass concentrations (MNH4/MOrg) in the particles increased monotonically from <5% RH to a limiting value at a threshold RH, implicating a switchover in the reaction kinetics from a system limited by diffusivity within the SOM for low RH to one limited by other factors, such as saturated uptake, at higher RH. Formation of ON was observed for aromatic-derived SOMs, but not significant for terpenoid-derived SOMs. For aromatic-derived SOMs, the ON-to-organic ratio of mass concentrations (MON/MOrg) was negligible for RH <20%, increased monotonically from 20% to 60% RH, and stayed constant for RH >60%. The threshold RH for the switchover from kinetically controlled regime to a non-kinetically-controlled one was thus different between formation of ammonium and ON. This difference suggests that water may play a role in the slow reactions of ON formation as a reactant or a catalyst, in addition to affecting the reactant diffusion as in the fast reaction of ammonium formation. The implication is that formation of ammonium salts and organic nitrogen species by certain SOMs should be treated separately in chemical transport models to reflect the different roles of water that may affect the phase state of the SOMs or may act as a reactant or a catalyst.

  8. Real-Time Secondary Aerosol Formation Measurements using a Photooxidation Reactor (PAM) and AMS in Urban Air and Biomass Smoke

    NASA Astrophysics Data System (ADS)

    Ortega, A. M.; Cubison, M.; Hayes, P. L.; Brune, W. H.; Hu, W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Alvarez, S. L.; Rappenglueck, B.; Bon, D.; Graus, M.; Warneke, C.; Gilman, J. B.; Kuster, W. C.; De Gouw, J. A.; Sullivan, A. P.; Jimenez, J. L.

    2011-12-01

    Recent field studies reveal large formation of secondary organic aerosol (SOA) under urban polluted ambient conditions, while SOA formation in biomass burning smoke appears to be variable but sometimes substantial. To study this formation in real-time, a Potential Aerosol Mass (PAM) photooxidation reactor was deployed with submicron aerosol size and chemical composition measurements during two studies: FLAME-3, a biomass-burning study at USDA Fire Sciences Laboratory in Missoula in 2009, MT and CalNex-LA in Pasadena, CA in 2010. A high-resolution aerosol mass spectrometer (HR-AMS) and a scanning mobility particle sizer (SMPS) alternated sampling unprocessed and PAM-processed aerosol. The PAM reactor produces OH concentrations up to 4 orders of magnitude higher than in ambient air, achieving equivalent aging of ~2 weeks in 5 minutes of processing. The OH intensity was also scanned every 20 min. in both field studies. Results show the value of PAM-AMS as a tool for in-situ evaluation of changes in OA concentration and composition due to SOA formation and POA oxidation. In FLAME-3, net SOA formation was variable among smokes from different biomasses; however, OA oxidation was always observed. The average SOA enhancement factor was 1.7 +/- 0.5 of the initial POA. Reactive VOCs such as toluene, monoterpenes, and acetaldehyde, as measured from a PIT-MS, decreased with increased PAM processing; however, formic acid, acetone, and some unidentified OVOCs increased after significant exposure to high oxidant levels suggesting multigenerational chemistry. Results from CalNex-LA show enhancement of SOA and inorganic aerosol from gas-phase precursors. This enhanced OA mass increase from PAM processing is maximum at night and correlates with trimethylbenzene concentrations, which indicates the dominance of short-lived SOA precursors in the LA Basin. A traditional SOA model with mostly aromatic precursors underpredicts the amount of SOA formed by about an order-of-magnitude, which

  9. Subclavian artery pseudoaneurysm: a rare and serious complication of central venous catheterization in an infant.

    PubMed

    Koklu, Esad; Poyrazoglu, Hakan; Yikilmaz, Ali; Canpolat, Mehmet; Konuskan, Bahadir

    2008-02-01

    Serious complications of central venous access occur in 0.4-9.9% of patients undergoing attempted central venepuncture. We report an unusual case of an 18-month-old infant in whom a right subclavian artery pseudoaneurysm developed rapidly after attempted subclavian vein catheterization without US guidance failed.

  10. Infectious anastomotic pseudoaneurysm complicating renal allograft: case report and review of literature

    PubMed Central

    Chung, Marvin MT; Chan, Yiu Che; Law, Yuk; Cheng, Stephen WK

    2017-01-01

    Infectious anastomotic pseudoaneurysm complicating renal transplant is rare, but probably under-reported with <30 cases worldwide. We report a 45-year-old man with hypertension, diabetes mellitus and end stage renal failure, who had a renal transplant anastomosed to the right external iliac artery and vein. Postoperatively, he made a slow recovery with malaise and persistent vague right iliac fossa discomfort. Ultrasound scan 1 month postoperatively showed perinephric collection, and fluid culture grew Enterococcus faecium and Pseudomonas aeruginosa. He was started on vancomycin, daptomycin and colistin. MAG-3 scan also showed suboptimal function in the renal allograft. His symptoms persisted with fever, and blood culture yielded P. aeruginosa. Repeated ultrasound scan, and subsequent computed tomography scan a few weeks later, showed perinephric collection and a large, 3.8×3.5 cm pseudoaneurysm posteromedial to the graft kidney. He underwent emergency graft excision, together with resection of the pseudoaneurysm with in situ reversed great saphenous vein interposition graft, and made a good recovery on hemodialysis. The aneurysm wall grew P. aeruginosa, and he was put on imipenem and cilastatin (tienam), colistin, ciprofloxacin and daptomycin. To our knowledge, this is one of very few cases in the world’s literature in which a P. aeruginosa infectious anastomotic pseudoaneurysm developed after a renal allograft. PMID:28260939

  11. Arterial Pseudoaneurysm Associated with Pancreas and Kidney Transplantation: A Case Report

    PubMed Central

    Arantes, Rubens Macedo; Pantanali, Carlos Andrés Rodriguez; Santos, Vinicius Rocha; D’Albuquerque, Luiz Augusto Carneiro

    2017-01-01

    Patient: Male, 49 Final Diagnosis: Arterial pseudoaneurysm Symptoms: Abdominal pain • fever and a pulsatile tumor located in the right iliac fossa Medication: — Clinical Procedure: Endovascular and surgical approach Specialty: Transplantology Objective: Unusual clinical course Background: Pseudoaneurysm is a rare vascular complication in pancreas transplantation. This complication develops from a disruption of the arterial continuity, usually related to trauma, infection, vasculitis, or complications in vascular procedures. Case Report: A 43-year-old man underwent simultaneous pancreas and kidney transplantation for end-stage renal disease. He subsequently developed acute pancreatitis and acute kidney cellular rejection as late complications, thus returning to hemodialysis. A new, uneventful kidney transplantectomy and living donor kidney transplant was performed. One year after the last transplant, the patient presented with moderate abdominal pain, fever, and a pulsatile tumor located in the right iliac fossa. A pseudoaneurysm located in the pancreatic Y graft was observed. The patient was treated using an endovascular and surgical approach. Conclusions: A combined procedure using an endovascular and surgical approach promoted a good vascular control with a lower risk of bleeding in a rare case of pseudoaneurysm in a transplant patient. PMID:28232659

  12. Brachial plexus compression due to subclavian artery pseudoaneurysm from internal jugular vein catheterization

    PubMed Central

    Mol, T. N.; Gupta, A.; Narain, U.

    2017-01-01

    Internal jugular vein (IJV) catheterization has become the preferred approach for temporary vascular access for hemodialysis. However, complications such as internal carotid artery puncture, vessel erosion, thrombosis, and infection may occur. We report a case of brachial plexus palsy due to compression by right subclavian artery pseudoaneurysm as a result of IJV catheterization in a patient who was under maintenance hemodialysis. PMID:28356671

  13. Percutaneous Glue Embolization of a Visceral Artery Pseudoaneurysm in a Case of Sickle Cell Anemia

    SciTech Connect

    Gulati, Gurpreet S.; Gulati, Manpreet S. Makharia, Govind; Hatimota, Pradeep; Saikia, Nripen; Paul, Shashi B.; Acharya, Subrat

    2006-08-15

    Although aneurysmal complications of sickle cell anemia have been described in the intracranial circulation, visceral artery pseudoaneurysms in this disease entity have not previously been reported in the literature. Conventional treatment of visceral pseudoaneurysms has been surgical ligation or resection of the aneurysm. Transcatheter embolization has emerged as an attractive, minimally invasive alternative to surgery in the treatment of these lesions. In certain situations, however, due to the unfavorable angiographic anatomy precluding safe transcatheter embolization, direct percutaneous glue injection of the pseudoaneurysm sac may be considered to achieve successful occlusion of the sac. The procedure may be rendered safer by simultaneous balloon protection of the parent artery. We describe this novel treatment modality in a case of inferior pancreaticoduodenal artery pseudoaneurysm in a patient with sickle cell anemia. Although a complication in the form of glue reflux into the parent vessel occurred that necessitated surgery, this treatment modality may be used in very selected cases (where conventional endovascular embolization techniques are not applicable) after careful selection of the balloon diameter and appropriate concentration of the glue-lipiodol mixture.

  14. Pseudoaneurysm of the internal maxillary artery: A case report of facial trauma and recurrent bleeding

    PubMed Central

    Alonso, Nivaldo; de Oliveira Bastos, Endrigo; Massenburg, Benjamin B.

    2016-01-01

    Introduction Pseudoaneurysms occur when there is a partial disruption in the wall of a blood vessel, causing a hematoma that is either contained by the vessel adventitia or the perivascular soft tissue. Presentation of case A 32-year-old male presented to the emergency department presented with comminuted fractures in the left zygoma, ethmoids, and the right ramus of the mandible following a gunshot wound. The patient underwent open reduction of his fractures and the patient was discharged on the eighth day after the trauma. Thirteen days after the discharge and 21 days after the gunshot wound, the patient returned to the ER due to heavy nasopharyngeal bleeding that compromised the patency of the patient’s airways and caused hemodynamic instability. Arteriography of the facial blood vessels revealed a pseudoaneurysm of the maxillary artery. Endovascular embolization with a synthetic embolic agent resulted in adequate hemostasis, and nine days after embolization the patient was discharged. Discussion The diagnosis of pseudoaneurysm is suggested by history and physical examination, and confirmed by one of several imaging methods, such as CT scan with contrast. Progressive enlargement of the lesion may lead to several complications, including rupture of the aneurysm and hemorrhage, compression of adjacent nerves, or release of embolic thrombi. Conclusion This case reports the long-term follow up and natural history of a patient with a post-traumatic pseudoaneurysm of the internal maxillary artery and the successful use of endovascular embolization to treat the lesion. PMID:26942333

  15. Intractable Postpartum Hemorrhage Resulting from Uterine Artery Pseudoaneurysm: Superselective Arteriographic Embolization via the Collateral Route

    SciTech Connect

    Doenmez, Halil Oztuerk, M. Halil; Guergen, Fatma; Soylu, Serra O.; Hekimoglu, Baki

    2007-04-15

    We present a patient with intractable postpartum hemorrhage resulting from uterine artery pseudoaneurysm despite bilateral hypogastric artery ligation who was successfully treated by an endovascular approach via the collateral route. Although there is a good argument for postponing surgery until transcatheter embolization has been attempted, this case shows that embolization can still be successful even if the iliac vessels have been ligated.

  16. Identifying new components participating in the secondary cell wall formation of vessel elements in zinnia and Arabidopsis.

    PubMed

    Endo, Satoshi; Pesquet, Edouard; Yamaguchi, Masatoshi; Tashiro, Gen; Sato, Mayuko; Toyooka, Kiminori; Nishikubo, Nobuyuki; Udagawa-Motose, Makiko; Kubo, Minoru; Fukuda, Hiroo; Demura, Taku

    2009-04-01

    Xylem vessel elements are hollow cellular units that assemble end-to-end to form a continuous vessel throughout the plant body; the xylem vessel is strengthened by the xylem elements' reinforced secondary cell walls (SCWs). This work aims to unravel the contribution of unknown actors in xylem vessel differentiation using the model in vitro cell culture system of Zinnia elegans differentiating cell cultures and the model in vivo system of Arabidopsis thaliana plants. Tracheary Element Differentiation-Related6 (TED6) and TED7 were selected based on an RNA interference (RNAi) screen in the Zinnia system. RNAi reduction of TED6 and 7 delayed tracheary element (TE) differentiation and co-overexpression of TED6 and 7 increased TE differentiation in cultured Zinnia cells. Arabidopsis TED6 and 7 were expressed preferentially in differentiating vessel elements in seedlings. Aberrant SCW formation of root vessel elements was induced by transient RNAi of At TED7 alone and enhanced by inhibition of both TED6 and 7. Protein-protein interactions were demonstrated between TED6 and a subunit of the SCW-related cellulose synthase complex. Our strategy has succeeded in finding two novel components in SCW formation and has opened the door for in-depth analysis of their molecular functions.

  17. Contributions of vehicular emissions and secondary formation to nitrous acid concentrations in ambient urban air in Tokyo in the winter.

    PubMed

    Nakashima, Yoshihiro; Sadanaga, Yasuhiro; Saito, Shinji; Hoshi, Junya; Ueno, Hiroyuki

    2017-03-15

    Nitrous acid (HONO) plays an important role in the formation of OH radicals, which are involved in photochemical oxidation. HONO concentrations in ambient air at urban sites have previously been measured, but very few studies have been performed in central Tokyo. In this study, HONO concentrations in ambient air in southeast central Tokyo (near Tokyo Bay) in winter were determined by incoherent cavity enhanced absorption spectroscopy. The O3, NO, NO2, and SO2 concentrations were simultaneously determined. The NO concentrations were used to classify the parts of the study period into types I (high pollution), II (medium pollution), and III (low pollution). The maximum HONO concentrations in the type I, II, and III periods were 7.1, 4.5, and 3.0ppbv, respectively. These concentrations were comparable to concentrations previously found in other Asian megacities. The mean HONO concentration varied diurnally, and HONO was depleted between 00:00 and 03:00 each day. The sampling site is surrounded by roads with high traffic loads, but vehicular emissions were estimated to contribute <10% of the HONO concentrations. Two positive and negative relative humidity dependences of the HONO to NO2 ratio were confirmed, implying the existence of the two different secondary formation process of HONO. The NO2 to HONO conversion rates at night in the type I, II, and III periods were 6.3×10(-3), 7.6×10(-3), and 4.2×10(-3)h(-1), respectively.

  18. Secondary Organic Aerosol Formation over Coastal Ocean: Inferences from Atmospheric Water-Soluble Low Molecular Weight Organic Compounds.

    PubMed

    Bikkina, Srinivas; Kawamura, Kimitaka; Sarin, Manmohan

    2017-04-07

    A lack of consensus on the distributions and formation pathways of secondary organic aerosols (SOA) over oceanic regions downwind of pollution sources limits our ability to assess their climate impact globally. As a case study, we report here on water-soluble SOA components such as dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls in the continental outflows from the Indo-Gangetic Plain (IGP) and Southeast Asia (SEA) to the Bay of Bengal. Oxalic acid (C2) is the dominant species followed by succinic (C4) and glyoxylic acids (ωC2) in the outflow. Nonsea-salt SO4(2-) also dominates (∼70%) total water-soluble inorganic constituents and correlates well with aerosol liquid water content (LWC) and C2, indicating their production through aqueous phase photochemical reactions. Furthermore, mass ratios of dicarboxylic acids (C2/C4, C2/ωC2), and their relative abundances in water-soluble organic carbon and total organic carbon are quite similar between the two continental (IGP and SEA) outflows, indicating the formation of SOA through aqueous phase photochemical reactions in LWC-enriched aerosols, largely controlled by anthropogenic SO4(2-).

  19. Identifying New Components Participating in the Secondary Cell Wall Formation of Vessel Elements in Zinnia and Arabidopsis[W

    PubMed Central

    Endo, Satoshi; Pesquet, Edouard; Yamaguchi, Masatoshi; Tashiro, Gen; Sato, Mayuko; Toyooka, Kiminori; Nishikubo, Nobuyuki; Udagawa-Motose, Makiko; Kubo, Minoru; Fukuda, Hiroo; Demura, Taku

    2009-01-01

    Xylem vessel elements are hollow cellular units that assemble end-to-end to form a continuous vessel throughout the plant body; the xylem vessel is strengthened by the xylem elements' reinforced secondary cell walls (SCWs). This work aims to unravel the contribution of unknown actors in xylem vessel differentiation using the model in vitro cell culture system of Zinnia elegans differentiating cell cultures and the model in vivo system of Arabidopsis thaliana plants. Tracheary Element Differentiation-Related6 (TED6) and TED7 were selected based on an RNA interference (RNAi) screen in the Zinnia system. RNAi reduction of TED6 and 7 delayed tracheary element (TE) differentiation and co-overexpression of TED6 and 7 increased TE differentiation in cultured Zinnia cells. Arabidopsis TED6 and 7 were expressed preferentially in differentiating vessel elements in seedlings. Aberrant SCW formation of root vessel elements was induced by transient RNAi of At TED7 alone and enhanced by inhibition of both TED6 and 7. Protein–protein interactions were demonstrated between TED6 and a subunit of the SCW-related cellulose synthase complex. Our strategy has succeeded in finding two novel components in SCW formation and has opened the door for in-depth analysis of their molecular functions. PMID:19383897

  20. Graft union formation in grapevine induces transcriptional changes related to cell wall modification, wounding, hormone signalling, and secondary metabolism

    PubMed Central

    Cookson, Sarah Jane; Clemente Moreno, Maria José; Hevin, Cyril; Nyamba Mendome, Larissa Zita; Delrot, Serge; Trossat-Magnin, Claudine; Ollat, Nathalie

    2013-01-01

    Grafting is particularly important to the cultivation of perennial crops such as grapevine (Vitis vinifera) because rootstocks can provide resistance to soil-borne pests and diseases as well as improve tolerance to some abiotic stresses. Successful grafting is a complex biochemical and structural process beginning with the adhesion of the two grafted partners, followed by callus formation and the establishment of a functional vascular system. At the molecular level, the sequence of events underlying graft union formation remains largely uncharacterized. The present study investigates the transcriptome of grapevine rootstock and graft interface tissues sampled 3 d and 28 d after grafting of over-wintering stems in the spring. Many genes were differentially expressed over time, from 3 d to 28 d after grafting, which could be related to the activation of stem growth and metabolic activity in the spring. This hypothesis is supported by the up-regulation of many genes associated with cell wall synthesis, and phloem and xylem development. Generally, there was an up-regulation of gene expression in the graft interface tissue compared with the rootstock, particularly genes involved in cell wall synthesis, secondary metabolism, and signalling. Although there was overlap between the genes differentially expressed over time (from 3 d to 28 d after grafting) with the gene differentially expressed between the rootstock and the graft interface, numerous graft interface-specific genes were identified. PMID:23698628

  1. simpleGAMMA - a reduced model of secondary organic aerosol formation in the aqueous aerosol phase (aaSOA)

    NASA Astrophysics Data System (ADS)

    Woo, J. L.; McNeill, V. F.

    2015-01-01

    There is increasing evidence that the uptake and aqueous processing of water-soluble volatile organic compounds (VOCs) by wet aerosols or cloud droplets is an important source of secondary organic aerosol (SOA). We recently developed GAMMA (Gas-Aerosol Model for Mechanism Analysis), a zero-dimensional kinetic model that couples gas-phase and detailed aqueous-phase atmospheric chemistry for speciated prediction of SOA and organosulfate formation in cloudwater or aqueous aerosols. Results from GAMMA simulations of SOA formation in aerosol water (McNeill et al., 2012) indicate that it is dominated by two pathways: isoprene epoxydiol (IEPOX) uptake followed by ring-opening chemistry (under low-NOx conditions) and glyoxal uptake. This suggested that it is possible to model the majority of aqueous aerosol phase SOA mass using a highly simplified reaction scheme. We have therefore developed a reduced version of GAMMA, simpleGAMMA. Close agreement in predicted aaSOA mass is observed between simpleGAMMA and GAMMA under all conditions tested (between pH 1-4 and RH 40-80%) after 12 h of simulation. simpleGAMMA is computationally efficient and suitable for coupling with larger-scale atmospheric chemistry models.

  2. Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation.

    PubMed

    Krechmer, Jordan E; Coggon, Matthew M; Massoli, Paola; Nguyen, Tran B; Crounse, John D; Hu, Weiwei; Day, Douglas A; Tyndall, Geoffrey S; Henze, Daven K; Rivera-Rios, Jean C; Nowak, John B; Kimmel, Joel R; Mauldin, Roy L; Stark, Harald; Jayne, John T; Sipilä, Mikko; Junninen, Heikki; Clair, Jason M St; Zhang, Xuan; Feiner, Philip A; Zhang, Li; Miller, David O; Brune, William H; Keutsch, Frank N; Wennberg, Paul O; Seinfeld, John H; Worsnop, Douglas R; Jimenez, Jose L; Canagaratna, Manjula R

    2015-09-01

    Gas-phase low volatility organic compounds (LVOC), produced from oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC directly correspond to appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA below 1 μg m(-3)). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The SOA formation in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxidation in the chamber study implies a wall-loss corrected non-IEPOX SOA mass yield of ∼4%. By contrast to monoterpene oxidation, in which extremely low volatility VOC (ELVOC) constitute the organic aerosol, in the isoprene system LVOC with saturation concentrations from 10(-2) to 10 μg m(-3) are the main constituents. These LVOC may be important for the growth of nanoparticles in environments with low OA concentrations. LVOC observed in the chamber were also observed in the atmosphere during SOAS-2013 in the Southeastern United States, with the expected diurnal cycle. This previously uncharacterized aerosol formation pathway could account for ∼5.0 Tg yr(-1) of SOA production, or 3.3% of global SOA.

  3. Systematic Review of Interventions to Repair Ascending Aortic Pseudoaneurysms

    PubMed Central

    Quevedo, Henry C.; Santiago-Trinidad, Ricardo; Castellanos, Jorge; Atianzar, Kimberly; Anwar, Asif; Rafeh, Nidal Abi

    2014-01-01

    Background The safety and efficacy of endovascular therapies for ascending aortic pseudoaneurysms (AAPs) are still controversial. Methods We report an endovascular correction of an AAP in a high-risk surgical patient and present the results of a literature review focusing on AAP treatment strategies. A multilingual search of AAP therapy was performed with limiting dates of January 1980 to May 2014. The studies were classified by intervention. Results A 79-year-old male with a 9 × 10 × 7 cm AAP in the anterior mediastinum was considered too high risk for surgery. An endovascular closure with a 12 mm Amplatzer septal occluder device (St. Jude Medical) was performed, and computed tomography angiography at 3-month follow-up exhibited a thrombosed AAP with minimal residual shunt. In our literature search, we identified 355 cases of AAPs, mostly case reports (91.5%) and a few patient series (8.5%). Surgical correction accounted for 73.8% of the cases, 5% of the patients were conservatively treated or considered too critically ill for any intervention, and 21.2% were treated with endovascular techniques. The most commonly reported endovascular techniques were stent grafts (9.8%) and septal occluder devices (9.8%). Conclusion Although endovascular closure of AAPs with off-label devices is a reliable option for controlling the expansion and symptoms in high-risk surgical patients, solid data on survival are lacking. Efforts to promote discussion within the heart team to expand the application of endovascular techniques can provide groundbreaking evidence to support the use of endovascular techniques as guideline therapy when facing these complicated cases. PMID:25598723

  4. Seasonal variation and secondary formation of size-segregated aerosol water-soluble inorganic ions during pollution episodes in Beijing

    NASA Astrophysics Data System (ADS)

    Huang, Xiaojuan; Liu, Zirui; Zhang, Junke; Wen, Tianxue; Ji, Dongsheng; Wang, Yuesi

    2016-02-01

    Particulate matter (PM) pollution is a serious issue that has aroused great public attention in Beijing. To examine the seasonal characteristics of aerosols in typical pollution episodes, water-soluble inorganic ions (SO42 -, NO3-, NH4+, Cl-, K+, Na+, Ca2 + and Mg2 +) in size-segregated PM collected by an Anderson sampler (equipped with 50% effective cut-off diameters of 9.0, 5.8, 4.7, 3.3, 2.1, 1.1, 0.65, 0.43 μm and an after filter) were investigated in four intensive campaigns from June 2013 to May 2014 in the Beijing urban area. Pronounced seasonal variation of TWSIs in fine particles (aerodynamic diameter less than 2.1 μm) was observed, with the highest concentration in summer (71.5 ± 36.3 μg/m3) and the lowest in spring (28.1 ± 15.2 μg/m3). Different ion species presented different seasonal characteristics of mass concentration and size distribution, reflecting their different dominant sources. As the dominant component, SO42 -, NO3- and NH4+ (SNA) in fine particles appeared to play an important role in the formation of high PM pollution since its contribution to the TWSIs and PM2.1 mass increased significantly during pollution episodes. Due to the hygroscopic growth and enhanced secondary formation in the droplet mode (0.65-2.1 μm) from clean days to polluted days, the size distribution peak of SNA in the fine mode tended to shift from 0.43-0.65 μm to 0.65-2.1 μm. Relative humidity (RH) and temperature contributed to influence the secondary formation and regulate the size distributions of sulfates and nitrates. Partial correlation analysis found that high RH would promote the sulfur and nitrogen oxidation rates in the fine mode, while high temperature favored the sulfur oxidation rate in the condensation mode (0.43-0.65 μm) and reduced the nitrogen oxidation rate in the droplet mode (0.65-2.1 μm). The NO3-/SO42 - mass ratio in PM2.1 (73% of the samples) exceeded 1.0, suggesting that vehicle exhaust currently makes a greater contribution to aerosol

  5. Secondary Organic Aerosol Formation from Ambient Air in an Oxidation Flow Reactor at GoAmazon2014/5

    NASA Astrophysics Data System (ADS)

    Palm, Brett B.; de Sa, Suzane S.; Campuzano-Jost, Pedro; Day, Douglas A.; Hu, Weiwei; Seco, Roger; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Brito, Joel; Wurm, Florian; Artaxo, Paulo; Yee, Lindsay; Isaacman-VanWertz, Gabrial; Goldstein, Allen; Newburn, Matt K.; Lizabeth Alexander, M.; Martin, Scot T.; Brune, William H.; Jimenez, Jose L.

    2016-04-01

    During GoAmazon2014/5, ambient air was exposed to controlled concentrations of OH or O3 in situ using an oxidation flow reactor (OFR). Oxidation ranged from hours-several weeks of aging. Oxidized air was sampled by several instruments (e.g., HR-AMS, ACSM, PTR-TOF-MS, SMPS, CCN) at both the T3 site (IOP1: Feb 1-Mar 31, 2014, and IOP2: Aug 15-Oct 15, 2014) and T2 site (between IOPs and into 2nd IOP). The oxidation of ambient air in the OFR led to substantial and variable secondary organic aerosol (SOA) formation from any SOA-precursor gases, known and unknown, that entered the OFR. In general, more SOA was produced during the nighttime than daytime, suggesting that SOA-precursor gases were found in relatively higher concentrations at night. Similarly, more SOA was formed in the dry season (IOP2) than wet season (IOP1). The maximum amount of SOA produced during nighttime from OH oxidation ranged from less than 1 μg/m3 on some nights to greater than 10 μg/m3 on other nights. O3 oxidation of ambient air also led to SOA formation, although several times less than from OH oxidation. The amount of SOA formation sometimes, but not always, correlated with measured gas-phase biogenic and/or anthropogenic SOA precursors (e.g., SV-TAG sesquiterpenes, PTR-TOFMS aromatics, isoprene, and monoterpenes). The SOA mass formed in the OFR from OH oxidation was up to an order of magnitude larger than could be explained from aerosol yields of measured primary VOCs. This along with measurements from previous campaigns suggests that most SOA was formed from intermediate S/IVOC sources (e.g., VOC oxidation products, evaporated POA, or direct emissions). To verify the SOA yields of VOCs under OFR experimental conditions, atmospherically-relevant concentrations of several VOCs were added individually into ambient air in the OFR and oxidized by OH or O3. SOA yields in the OFR were similar to published chamber yields. Preliminary PMF factor analysis showed production of secondary factors in

  6. Atmospheric fate of OH initiated oxidation of terpenes. Reaction mechanism of alpha-pinene degradation and secondary organic aerosol formation.

    PubMed

    Librando, Vito; Tringali, Giuseppe

    2005-05-01

    This paper studies the reaction products of alpha-pinene, beta-pinene, sabinene, 3-carene and limonene with OH radicals and of alpha-pinene with ozone using FT-IR spectroscopy for measuring gas phase products and HPLC-MS-MS to measure products in the aerosol phase. These techniques were used to investigate the secondary organic aerosol (SOA) formation from the terpenes. The gas phase reaction products were all quantified using reference compounds. At low terpene concentrations (0.9-2.1 ppm), the molar yields of gas phase reaction products were: HCHO 16-92%, HCOOH 10-54% (OH source: H2O2, 6-25 ppm); HCHO 127-148%, HCOOH 4-6% (OH source: CH3ONO, 5-8 ppm). At high terpene concentrations (4.1-13.2 ppm) the results were: HCHO 9-27%, HCOOH 15-23%, CH3(CO)CH3 0-14%, CH3COOH 0-5%, nopinone 24% (only from beta-pinene oxidation), limona ketone 61% (only from limonene oxidation), pinonaldehyde was identified during alpha-pinene degradation (OH source H2O2, 23-30 ppm); HCHO 76-183%, HCOOH 12-15%, CH3(CO)CH3 0-12%, nopinone 17% (from beta-pinene oxidation), limona ketone 48% (from limonene oxidation), pinonaldehyde was identified during alpha-pinene degradation (OH source CH3ONO, 14-16 ppm). Pinic acid, pinonic acid, limonic acid, limoninic acid, 3-caric acid, 3-caronic acid and sabinic acid were identified in the aerosol phase. On the basis of these results, we propose a formation mechanism for pinonic and pinic acid in the aerosol phase explaining how degradation products could influence SOA formation and growth in the troposphere.

  7. Morphology of mixed primary and secondary organic particles and the adsorption of spectator organic gases during aerosol formation

    PubMed Central

    Vaden, Timothy D.; Song, Chen; Zaveri, Rahul A.; Imre, Dan; Zelenyuk, Alla

    2010-01-01

    Primary organic aerosol (POA) and associated vapors can play an important role in determining the formation and properties of secondary organic aerosol (SOA). If SOA and POA are miscible, POA will significantly enhance SOA formation and some POA vapor will incorporate into SOA particles. When the two are not miscible, condensation of SOA on POA particles forms particles with complex morphology. In addition, POA vapor can adsorb to the surface of SOA particles increasing their mass and affecting their evaporation rates. To gain insight into SOA/POA interactions we present a detailed experimental investigation of the morphologies of SOA particles formed during ozonolysis of α-pinene in the presence of dioctyl phthalate (DOP) particles, serving as a simplified model of hydrophobic POA, using a single-particle mass spectrometer. Ultraviolet laser depth-profiling experiments were used to characterize two different types of mixed SOA/DOP particles: those formed by condensation of the oxidized α-pinene products on size-selected DOP particles and by condensation of DOP on size-selected α-pinene SOA particles. The results show that the hydrophilic SOA and hydrophobic DOP do not mix but instead form layered phases. In addition, an examination of homogeneously nucleated SOA particles formed in the presence of DOP vapor shows them to have an adsorbed DOP coating layer that is ∼4 nm thick and carries 12% of the particles mass. These results may have implications for SOA formation and behavior in the atmosphere, where numerous organic compounds with various volatilities and different polarities are present. PMID:20194795

  8. Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest

    NASA Astrophysics Data System (ADS)

    Mochizuki, T.; Miyazaki, Y.; Ono, K.; Wada, R.; Takahashi, Y.; Saigusa, N.; Kawamura, K.; Tani, A.

    2015-04-01

    We conducted simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene, along with their oxidation products in aerosols in a Larix kaempferi (Japanese larch) forest in summer 2012. Vertical profiles of isoprene showed the maximum concentration near the forest floor with a peak around noon, whereas oxidation products of isoprene, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), showed higher concentrations near the canopy level of the forest. The vertical profile suggests large emissions of isoprene near the forest floor, likely due to Dryopteris crassirhizoma (a fern species), and the subsequent reaction within the canopy. The concentrations of α-pinene also showed highest values near the forest floor with maximums in the early morning and late afternoon. The vertical profiles of α-pinene suggest its large emissions from soil and litter in addition to emissions from L. kaempferi leaves at the forest site. Isoprene and its oxidation products in aerosols exhibited similar diurnal variations within the forest canopy, providing evidence for secondary organic aerosol (SOA) formation via oxidation of isoprene most likely emitted from the forest floor. Although high abundance of α-pinene was observed in the morning, its oxidation products in aerosols showed peaks in daytime, due to a time lag between the emission and atmospheric reactions of α-pinene to form SOA. Positive matrix factorization (PMF) analysis indicated that anthropogenic influence is the most important factor contributing to the elevated concentrations of molecular oxidation products of isoprene- (> 64%) and α-pinene-derived SOA (> 57%). The combination of the measured fluxes and vertical profiles of biogenic volatile organic compounds (BVOCs) suggests that the inflow of anthropogenic precursors/aerosols likely enhanced the formation of both isoprene- and α-pinene-SOA within the forest canopy even when the BVOC flux was relatively low. This study highlights

  9. Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

    NASA Astrophysics Data System (ADS)

    Liu, T.; Wang, X.; Deng, W.; Hu, Q.; Ding, X.; Zhang, Y.; He, Q.; Zhang, Z.; Lü, S.; Bi, X.; Chen, J.; Yu, J.

    2015-04-01

    In China, fast increase in passenger vehicles has procured the growing concern about vehicle exhausts as an important source of anthropogenic secondary organic aerosols (SOA) in megacities hard-hit by haze. However, there are still no chamber simulation studies in China on SOA formation from vehicle exhausts. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with the relative humidity around 50%. After aging at an OH exposure of 5 × 106 molecules cm-3 h, the formed SOA was 12-259 times as high as primary OA (POA). The SOA production factors (PF) were 0.001-0.044 g kg-1 fuel, comparable with those from the previous studies at the quite similar OH exposure. This quite lower OH exposure than that in typical atmospheric condition might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yield data in this study were well fit by a one-product gas-particle partitioning model and quite lower than those of a previous study investigating SOA formation form three idling passenger vehicles (Euro 2-Euro 4). Traditional single-ring aromatic precursors and naphthalene could explain 51-90% of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C/ΔO : C ranged from -0.59 to -0.36, suggesting that the oxidation chemistry in these experiments was a

  10. Secondary Organic Aerosol Formation from Ultra-Low Super Ultra-Low and Partial Zero Emission Vehicle Exhaust

    NASA Astrophysics Data System (ADS)

    Robinson, A. L.; Zhao, Y.; Lambe, A. T.; Saleh, R.; Saliba, G.; Maldonado, H.; Sardar, S.; Frodin, B.; Drozd, G.; Goldstein, A. H.; Kroll, J. H.; Cross, E. S.; Franklin, J. P.

    2015-12-01

    Secondary organic aerosol (SOA) is the dominant component of organic aerosol in many urban areas during the summertime. On-road light duty gasoline vehicles (LDGV) have been indicated as a major source of SOA precursors. Emissions of the SOA-forming non methane hydrocarbons (NMHCs) from on-road LDGV have been substantially reduced along with more stringent emission standards, leading to reduced potential for SOA formation. However, recent smog chamber measurements reported that the reductions in SOA formation were less than those in NMHC emissions, indicating that newer, low emitting vehicles may emit a more efficient of SOA precursors. Vehicles that meet the ultra-low, super ultra-low and partial zero emission standards have substantially lower NMHC emissions than vehicles tested in past studies. To better understand the effects of more stringent emission controls on the SOA formation, we conducted experiments 13 vehicles recruited from the Southern California vehicle fleet (five ultra-low emission vehicles, four super ultra-low emission vehicles and four partial zero emission vehicles) at the California Air Resources Board Haagen-Smit Laboratory. In addition, we investigated several vehicles compliant with older emission standards have also been investigated here to bridge the previous studies. Dilute vehicle exhaust were photo-oxidized in a smog chamber with the VOC-to-NOx ratio adjusted to simulate the photochemistry in urban air. Application of literature data from single-ring aromatic compounds cannot explain the observed SOA during chamber experiments. The average ratios between estimated and measured SOA for vehicles under different emission standards ranged from 0.04 to 0.71. Comprehensive measurements of SOA precursor emissions were made, including NMHCs, intermediate volatility and semi-volatile organic compounds. This study presents results of SOA production from these low emitting vehicles and compares the results with recently published data. This

  11. Real-Time Observations of Secondary Aerosol Formation and Aging from Different Emission Sources and Environments

    NASA Astrophysics Data System (ADS)

    Ortega, A. M.; Palm, B. B.; Hayes, P. L.; Day, D. A.; Cubison, M.; Brune, W. H.; Hu, W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Rappenglueck, B.; Bon, D.; Graus, M.; Warneke, C.; Gilman, J.; Kuster, W.; De Gouw, J. A.; Jimenez, J. L.

    2013-12-01

    To investigate atmospheric processing of direct urban and wildfire emissions, we deployed a photochemical flow reactor (Potential Aerosol Mass, PAM) with submicron aerosol size and chemical composition measurements during FLAME-3, a biomass-burning study at USDA Fire Sciences Laboratory in Missoula, MT, and CalNex, a field study investigating the nexus of air quality and climate change at a receptor site in the LA-Basin at Pasadena, CA. The reactor produces OH concentrations up to 4 orders of magnitude higher than in ambient air, achieving equivalent aging of ~2 weeks in 5 minutes of processing. The OH exposure (OHexp) was stepped every 20 min in both field studies. Results show the value of this approach as a tool for in-situ evaluation of changes in OA concentration and composition due to photochemical processing. In FLAME-3, the average OA enhancement factor was 1.42 × 0.36 of the initial POA. Reactive VOCs, such as toluene, monoterpenes, and acetaldehyde, decreased with increased OHexp; however, formic acid, acetone, and some unidentified OVOCs increased after significant exposure. Net SOA formation in the photochemical reactor increased with OHexp, typically peaking around 3 days of equivalent atmospheric photochemical age (OHexp ~3.9e11 molecules cm-3 s), then leveling off at higher exposures. Unlike other studies, no decrease in OA is observed at high exposure, likely due to lower max OHexp in this study due to very high OH reactivity. The amount of additional OA mass added from aging is positively correlated with initial POA concentration, but not with the total VOC concentration or the concentration of known SOA precursors. The mass of SOA formed often exceeded the mass of the known VOC precursors, indicating the likely importance of primary semivolatile/intermediate volatility species, and possibly of unidentified VOCs as SOA precursors in biomass burning smoke. Results from CalNex show enhancement of OA and inorganic aerosol from gas-phase precursors

  12. Traumatic Pseudoaneurysm of the Internal Maxillary Artery: A Rare Life-Threatening Hemorrhage as a Complication of Maxillofacial Fractures

    PubMed Central

    Nastro Siniscalchi, E.; Catalfamo, L.; Pitrone, A.; Papa, R.; Famà, F.; Lo Giudice, G.; Cervino, G.; De Ponte, F. S.

    2016-01-01

    Pseudoaneurysm of the internal maxillary artery due to a traumatic event is a rare condition. Pseudoaneurysms are usually directly produced by arteries break with extravasation of blood. The compressed perivascular tissue forms the wall of aneurysmal sac. Then, this sac gradually expands and can be damaged. It is rare to see pseudoaneurysms of IMA. They are usually associated with fracture of the neck of the mandible. To the best of our knowledge the pseudoaneurysm of the internal maxillary artery related to maxillofacial trauma is an event extremely rare in the literature and if not quickly managed can lead to the patient's death. This case underlines how the close cooperation between surgeons and radiologists results in a quick diagnosis and management of such pathological events. PMID:27999596

  13. Endovascular PTFE-Covered Stent for Treatment of an External Iliac Artery Pseudoaneurysm in the Presence of Chronic Infection

    SciTech Connect

    Warren, Martin J. Fabian, Sebastian; Tisi, Paul

    2007-07-15

    A 75-year-old woman with an external iliac artery pseudoaneurysm, thought to have resulted from a chronic loosening and infection of a total hip replacement, was successfully treated by placement of a covered endoluminal stent.

  14. Novel model of negative secondary ion formation and its use to refine the electronegativity of almost fifty elements.

    PubMed

    Wittmaack, Klaus

    2014-06-17

    This study aimed to examine the recently proposed idea that the ionic contribution to atomic bonds is essential in determining the charge state of sputtered atoms. Use was made of negative secondary ion yields reported by Wilson for a large number of elements implanted in silicon and then sputter profiled by Cs bombardment. The derived normalized ion yields (or fractions) P vary by 6 orders of magnitude, but the expected exponential dependence on the electron affinity EA is evident only vaguely. Remarkably, a correlation of similar quality is observed if the data are presented as a function of the ionization potential IP. With IP being the dominant (if not sole) contributor to the electronegativity χ, one is led to assume that P depends on the sum χ + EA. About 72% of the "nonsaturated" ion yields are in accordance with a dependence of the form P ∝ exp[(χ + EA)/ε], with ε ≅ 0.2 eV, provided the appropriate value of χ is selected from the electronegativity tables of Pauling (read in eV), Mulliken or Allen. However, each of the three sources contributes only about one-third to the favorable electronegativity data. This unsatisfactory situation initiated the idea to derive the "true" electronegativity χSIMS from the measured ion yields P(χ + EA), verified for 48 elements. Significant negative deviations of χSIMS from a smooth increase with increasing atomic number are evident for elements with special outer-shell electron configurations such as (n-1)d(g-1)ns(1) or (n-1)d(10)ns(2)np(1). The results strongly support the new model of secondary ion formation and provide means for refining electronegativity data.

  15. Leaching patterns and secondary phase formation during unsaturated leaching of UO{sub 2} at 90{degrees}C

    SciTech Connect

    Wronkiewicz, D.J.; Bates, J.K.; Gerding, T.J.; Veleckis, E.; Tani, B.S.

    1991-11-01

    Experiments are being conducted that examine the reaction of UO{sub 2} with dripping oxygenated ground water at 90{degrees}C. The experiments are designed to identify secondary phases formed during UO{sub 2} alteration, evaluate parameters controlling U release, and act as scoping tests for studies with spent fuel. This study is the first of its kind that examines the alteration of UO{sub 2} under unsaturated conditions expected to exist at the proposed Yucca Mountain repository site. Results suggest the UO{sub 2} matrix will readily react within a few months after being exposed to simulated Yucca Mountain conditions. A pulse of rapid U release, combined with the formation of dehydrated schoepite on the UO{sub 2} surface, characterizes the reaction between one to two years. Rapid dissolution of intergrain boundaries and spallation of UO{sub 2} granules appears to be responsible for much of the U released. Differential release of the UO{sub 2} granules may be responsible for much of the variation observed between duplicate experiments. Less than 5 wt % of the released U remains in solution or in a suspended form, while the remaining settles out of solution as fine particles or is reprecipitated as secondary phases. Subsequent to the pulse period, U release rates decline and a more stable assemblage of uranyl silicate phases are formed by incorporating cations from the ground water leachant. Uranophane, boltwoodite, and sklodowskite appear as the final solubility limiting phases that form in these tests. This observed paragenetic sequence (from uraninite to schoepite-type phases to uranyl silicates) is identical to those observed in weathered zones of natural uraninite occurrences. The combined results indicate that the release of radionuclides from spent fuel may not be limited by U solubility constraints, but that spallation of particulate matter may be an important, if not the dominant release mechanism affecting release.

  16. Stent graft implantation in an aortic pseudoaneurysm associated with a fractured Cheatham-Platinum stent in aortic coarctation.

    PubMed

    Kuhelj, Dimitrij; Berden, Pavel; Podnar, Tomaž

    2016-03-01

    We report a case of aortic pseudoaneurysm associated with a fractured bare Cheatham-Platinum stent following stenting for aortic coarctation. These complications were recognised 6 years after the implantation procedure and were successfully managed by percutaneous stent graft implantation. Staged approach for stent dilatation might prevent development of aortic pseudoaneurysms. In addition, careful follow-up is warranted after stenting for aortic coarctation, particularly in patients with recognised aortic wall injury.

  17. Pseudoaneurysms Occurring as a Result of Fractures Giving Rise to the Appearance of Pseudotumors: A Short Series

    SciTech Connect

    Farquharson, Finn; Haroon, Athar; Fleet, Mustafa

    2007-09-15

    Pseudoaneurysms are focal enlargements of the vascular lumen due to partial or complete disruption of the arterial wall. These are an uncommon complication of fractures. The presence of a pseudoaneurysm adjacent to a fracture fragment can cause a pressure effect. This pressure not only impairs fracture healing but sometimes can erode the adjacent bone, producing the appearance of a pseudotumor. We present two such cases and discuss the management of these patients.

  18. Percutaneous Thrombin Injection with a Distal Embolic Protection Device for Treatment of a Common Carotid Artery Pseudoaneurysm

    PubMed Central

    Lee, J.H.; Tseng, I.K.; Siegel, R.L.; Roychowdhury, S.

    2013-01-01

    Summary Carotid artery pseudoaneurysm is a rare complication from placement of an internal jugular triple lumen catheter. Endovascular stenting is the favored treatment option in the setting of traumatic carotid injury. In other parts of the body, specifically the femoral artery, thrombin injection has become the standard of care. We intend to show that effective management of carotid pseudoaneurysms can also be achieved with thrombin injection after placement of a distal embolic protection device. PMID:23693049

  19. Endovascular Treatment of Pseudoaneurysm of the Common Hepatic Artery with Intra-aneurysmal Glue (N-Butyl 2-Cyanoacrylate) Embolization

    SciTech Connect

    Garg, Ashwin Banait, Swati; Babhad, Sudeep; Kanchankar, Niraj; Nimade, Pradeep; Panchal, Chintan

    2007-09-15

    A 40-year-old man, a chronic alcoholic, presented with acute epigastric pain. Selective celiac arteriography showed a pseudoaneurysm arising from the common hepatic artery. We hereby describe a technical innovation where complete pseudoaneurysm exclusion was seen after intra-aneurysmal N-butyl 2-cyanoacrylate (glue) injection with preservation of antegrade hepatic arterial flow and conclude that intra-aneurysmal liquid injection may have potential as a therapeutic option to reconstruct a defective vessel wall and thereby maintain the antegrade flow.

  20. Pseudoaneurysm of the Internal Mammary Artery as an Unusual Cause of Post-sternotomy Hemorrhage: The Role of Multislice Computed Tomography in the Diagnosis and Treatment Planning

    SciTech Connect

    Kamath, Sridhar Unsworth-White, Jonathan; Wells, Irving P.

    2005-04-15

    Pseudoaneurysm of the internal mammary artery (IMA) following median sternotomy is extremely rare. To date, the reported cases are only in single figures. The majority of these pseudoaneurysms were suspected from the clinical presentation, echocardiography or computed tomography (CT) but were only confirmed on contrast angiography. This case report demonstrates the current ability to carry out detailed vascular imaging on a 16-slice CT scanner. This accurate delineation of the pseudoaneurysm allowed targeted therapeutic embolization to be performed without unnecessary angiographic imaging.

  1. Characterization of Organic Nitrate Formation in Limonene Secondary Organic Aerosol using High-Resolution Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Faxon, Cameron; Hammes, Julia; Peng, Jianfei; Hallquist, Mattias; Pathak, Ravi

    2016-04-01

    Previous work has shown that organic nitrates (RONO2) are prevalent in the boundary layer, and can contribute significantly to secondary organic aerosol formation. Monoterpenes, including limonene, have been shown to be precursors for the formation of these organic nitrates. Limonene has two double bonds, either of which may be oxidized by NO3 or O3. This leads to the generation of products that can subsequently condense or partition into the particle phase, producing secondary organic aerosol. In order to further elucidate the particle and gas phase product distribution of organic nitrates forming from the reactions of limonene and the nitrate radical (NO3), a series of experiments were performed in the Gothenburg Flow Reactor for Oxidation Studies at Low Temperatures (G-FROST), described by previous work. N2O5 was used as the source for NO3 and NO2, and a characterized diffusion source was used to introduce limonene into the flow reactor. All experiments were conducted in the absence of light, and the concentration of limonene was increased step-wise throughout each experiment to modify the ratio of N2O5to limonene. The experiments were conducted such that both limonene- and N2O5-limited regimes were present. Gas and particle phase products were measured using an iodide High-Resolution Time-of-Flight Mass Spectrometer (HR-ToF-CIMS) coupled to a Filter Inlet for Gases and AEROsols (FIGAERO, and particle size and SOA mass concentrations were derived using a Scanning Mobility Particle Sizer (SMPS). CIMS measurement techniques have previously been employed for the measurement of organic nitrate products of such compounds using multiple reagent ions. The use of this instrumentation allowed for the identification of chemical formulas for gas and particle phase species. The findings from the experiments will be presented in terms of the relative gas-particle partitioning of major products and the effects of N2O5/limonene ratios on product distributions. Additionally, a

  2. Primary emissions and secondary organic aerosol formation from the exhaust of a flex-fuel (ethanol) vehicle

    NASA Astrophysics Data System (ADS)

    Suarez-Bertoa, R.; Zardini, A. A.; Platt, S. M.; Hellebust, S.; Pieber, S. M.; El Haddad, I.; Temime-Roussel, B.; Baltensperger, U.; Marchand, N.; Prévôt, A. S. H.; Astorga, C.

    2015-09-01

    Incentives to use biofuels may result in increasing vehicular emissions of compounds detrimental to air quality. Therefore, regulated and unregulated emissions from a Euro 5a flex-fuel vehicle, tested using E85 and E75 blends (gasoline containing 85% and 75% of ethanol (vol/vol), respectively), were investigated at 22 and -7 °C over the New European Driving Cycle, at the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. Vehicle exhaust was comprehensively analyzed at the tailpipe and in a dilution tunnel. A fraction of the exhaust was injected into a mobile smog chamber to study the photochemical aging of the mixture. We found that emissions from a flex-fuel vehicle, fueled by E85 and E75, led to secondary organic aerosol (SOA) formation, despite the low aromatic content of these fuel blends. Emissions of regulated and unregulated compounds, as well as emissions of black carbon (BC) and primary organic aerosol (POA) and SOA formation were higher at -7 °C. The flex-fuel unregulated emissions, mainly composed of ethanol and acetaldehyde, resulted in very high ozone formation potential and SOA, especially at low temperature (860 mg O3 km-1 and up to 38 mg C kg-1). After an OH exposure of 10 × 106 cm-3 h, SOA mass was, on average, 3 times larger than total primary particle mass emissions (BC + POA) with a high O:C ratio (up to 0.7 and 0.5 at 22 and -7 °C, respectively) typical of highly oxidized mixtures. Furthermore, high resolution organic mass spectra showed high 44/43 ratios (ratio of the ions m/z 44 and m/z 43) characteristic of low-volatility oxygenated organic aerosol. We also hypothesize that SOA formation from vehicular emissions could be due to oxidation products of ethanol and acetaldehyde, both short-chain oxygenated VOCs, e.g. methylglyoxal and acetic acid, and not only from aromatic compounds.

  3. Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

    NASA Astrophysics Data System (ADS)

    Liu, T.; Wang, X.; Deng, W.; Hu, Q.; Ding, X.; Zhang, Y.; He, Q.; Zhang, Z.; Lü, S.; Bi, X.; Chen, J.; Yu, J.

    2015-08-01

    In China, a rapid increase in passenger vehicles has led to the growing concern of vehicle exhaust as an important source of anthropogenic secondary organic aerosol (SOA) in megacities hard hit by haze. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) operated in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with relative humidity at around 50 %. After aging at an OH exposure of 5 × 106 molecules cm-3 h, the formed SOA was 12-259 times as high as primary organic aerosol (POA). The SOA production factors (PF) were 0.001-0.044 g kg-1 fuel, comparable with those from the previous studies at comparable OH exposure. This quite lower OH exposure than that in typical atmospheric conditions might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yields in this study were well fit by a one-product gas-particle partitioning model but quite lower than those of a previous study investigating SOA formation from three idling passenger vehicles (Euro 2-4). Traditional single-ring aromatic precursors and naphthalene could explain 51-90 % of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C / ΔO : C ranged from -0.59 to -0.36, suggesting that the oxidation chemistry in these experiments was a combination of carboxylic acid and alcohol/peroxide formation.

  4. PtoMYB156 is involved in negative regulation of phenylpropanoid metabolism and secondary cell wall biosynthesis during wood formation in poplar

    PubMed Central

    Yang, Li; Zhao, Xin; Ran, Lingyu; Li, Chaofeng; Fan, Di; Luo, Keming

    2017-01-01

    Some R2R3 MYB transcription factors have been shown to be major regulators of phenylpropanoid biosynthetic pathway and impact secondary wall formation in plants. In this study, we describe the functional characterization