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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. Endovascular Treatment of Persistent Epistaxis due to Pseudoaneurysm Formation of the Ophthalmic Artery Secondary to Nasogastric Tube

    SciTech Connect

    Selcuk, Hakan Soylu, Nur; Albayram, Sait; Selcuk, Dogan; Ozer, Harun; Kocer, Naci; Islak, Civan

    2005-04-15

    We present the case of a 60-year-old man with persistent epistaxis for 20 days that had started 2 weeks after removal of a nasogastric tube placed for an abdominal operation. There was no pathologic finding at selective facial and internal maxillary artery injections. An injury to the ethmoidal branches of the ophthalmic arteries or other arterial origins of bleeding was suspected. The internal carotid artery angiography revealed a pseudoaneurysm of an anterior ethmoidal branch of the left ophthalmic artery. The pseudoaneurysm was occluded with NBCA-histoacryl (25%) injection.0.

  4. Endovascular Treatment of Persistent Epistaxis due to Pseudoaneurysm Formation of the Ophthalmic Artery Secondary to Nasogastric Tube

    SciTech Connect

    Selcuk, Hakan Soylu, Nur; Albayram, Sait; Selcuk, Dogan; Ozer, Harun; Kocer, Naci; Islak, Civan

    2005-04-15

    We present the case of a 60-year-old man with persistent epistaxis for 20 days that had started 2 weeks after removal of a nasogastric tube placed for an abdominal operation. There was no pathologic finding at selective facial and internal maxillary artery injections. An injury to the ethmoidal branches of the ophthalmic arteries or other arterial origins of bleeding was suspected. The internal carotid artery angiography revealed a pseudoaneurysm of an anterior ethmoidal branch of the left ophthalmic artery. The pseudoaneurysm was occluded with NBCA-histoacryl (25%) injection.

  5. Hemosuccus pancreaticus secondary to pseudoaneurysm of the splenic artery.

    PubMed

    Parada Blázquez, Mariano José; Núñez Ortiz, Andrea

    2017-10-01

    A 41-years-old male who presents abdominal pain and rectal bleeding with acute anemization. Both the gastroscopy and the colonoscopy dont identify any potential cause of bleeding. The computed tomography (CT) shows a pseudoaneurysm of the splenic artery. Gastrointestinal bleeding was attributed to a hemosuccus pancreaticus secondary to the pseudoaneurysm of the splenic artery. An arteriography was performed to embolize it. Pseudoaneurysm of the splenic artery is a rare cause of gastrointestinal bleeding. Given the risk of a rupture, the treatment is mandatory irrespective of the size or symptoms.

  6. 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

  7. 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

  8. Acute formation of a pseudoaneurysm adjacent to a previously clipped anterior communicating artery aneurysm.

    PubMed

    Shoja, Mohammadali M; Tubbs, R Shane; Cohen-Gadol, Aaron A

    2011-01-01

    Cerebral pseudoaneurysms, especially of the anterior communicating artery (ACoA), are rare. Herein, the authors report a 66-year-old patient who underwent successful clip ligation of a small ruptured ACoA aneurysm. Eighteen days after surgery, he suffered from another episode of subarachnoid hemorrhage due to the rupture of a newly formed pseudoaneurysm adjacent to the previously clipped aneurysm. This pseudoaneurysm was treated through clip ligation as well. A pseudoaneurysm may rarely form adjacent to a previously clipped cerebral aneurysm and should be included in the differential diagnosis of recurrent subarachnoid hemorrhage. Potential mechanisms of formation and management strategies for this challenging problem will be discussed.

  9. 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

  10. Acute formation of a pseudoaneurysm adjacent to a previously clipped anterior communicating artery aneurysm

    PubMed Central

    Shoja, Mohammadali M.; Tubbs, R. Shane; Cohen-Gadol, Aaron A.

    2011-01-01

    Background: Cerebral pseudoaneurysms, especially of the anterior communicating artery (ACoA), are rare. Case Description: Herein, the authors report a 66-year-old patient who underwent successful clip ligation of a small ruptured ACoA aneurysm. Eighteen days after surgery, he suffered from another episode of subarachnoid hemorrhage due to the rupture of a newly formed pseudoaneurysm adjacent to the previously clipped aneurysm. This pseudoaneurysm was treated through clip ligation as well. Conclusion: A pseudoaneurysm may rarely form adjacent to a previously clipped cerebral aneurysm and should be included in the differential diagnosis of recurrent subarachnoid hemorrhage. Potential mechanisms of formation and management strategies for this challenging problem will be discussed. PMID:21697973

  11. 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.

  12. [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.

  13. Osler's nodes, pseudoaneurysm formation, and sepsis complicating percutaneous radial artery cannulation.

    PubMed

    Cohen, A; Reyes, R; Kirk, M; Fulks, R M

    1984-12-01

    Percutaneous arterial cannulation is useful for hemodynamic monitoring and frequent arterial blood gas determinations in selected intensive care patients. However, this procedure is not without risk. We report a case of localized Osler node formation, distal to a radial artery catheter, associated with sepsis, pseudoaneurysm formation, and thrombosis at the site of catheterization. Complications of this technique require aggressive medical and, in selected cases, surgical intervention.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. [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.

  19. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Successful Treatment of Complex Regional Pain Syndrome with Pseudoaneurysm Excision and Median Nerve Neurolysis.

    PubMed

    Gillick, John L; Cooper, Jared B; Babu, Sateesh; Das, Kaushik; Murali, Raj

    2016-08-01

    Complex regional pain syndrome (CRPS), formerly referred to as reflex sympathetic dystrophy, is a pain syndrome characterized by severe pain, altered autonomic and motor function, and trophic changes. CRPS is usually associated with soft tissue injury or trauma. It has also been described as a rare complication of arterial access for angiography secondary to pseudoaneurysm formation. A 73-year-old woman underwent catheterization of the left brachial artery for angiography of the celiac artery. The following day, the patient noticed numbness and severe pain in the median nerve distribution of the left upper extremity. Over the next 6 months, the patient developed CRPS in the left hand with pain and signs of autonomic dysfunction. Further work-up revealed the formation of a left brachial artery pseudoaneurysm with impingement on the median nerve. She underwent excision of the pseudoaneurysm with decompression and neurolysis of the left median nerve. Approximately 6 weeks after surgery, the patient had noticed significant improvement in autonomic symptoms. This case involves a unique presentation of CRPS caused by brachial artery angiography and pseudoaneurysm formation. In addition, the case demonstrates the efficacy of pseudoaneurysm excision and median nerve neurolysis in the treatment of CRPS as a rare complication of arterial angiography. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. 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

  8. Pseudoaneurysm formation after medtronic freestyle porcine aortic bioprosthesis implantation: a word of caution.

    PubMed

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

    2014-12-01

    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. 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. 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. 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 root replacement, which may not be feasible

  9. 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.

  10. [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.

  11. [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.

  12. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. [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.

  14. 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

  15. Hepatic artery pseudoaneurysm; a rare complication of amoebic liver abscess.

    PubMed

    Khan, Anam; Pal, Khawaja Muhammad Inam; Khan, Hussain Ijaz

    2011-08-01

    Hepatic artery pseudoaneurysm (HAP) is an infrequently encountered entity, usually seen secondary to blunt or penetrating trauma. The clinical presentation is often due to complications such as intrahepatic or intraperitoneal bleeding as a result of rupture of the pseudoaneurysm. Diagnosis is frequently delayed and made by splanchnic angiography. HAP associated with a liver abscess, has very rarely been described in the literature. We report the case of a 50-year-old man with amoebic liver abscess and right hepatic artery pseudoaneurysm which was suspected on high resolution contrast-enhanced abdominal computer tomography (CT). The lesion was confirmed by arteriography and treated prophylactically with transcatheteter embolization.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Renal aneurysms and pseudoaneurysms.

    PubMed

    Cura, Marco; Elmerhi, Fadi; Bugnogne, Alejandro; Palacios, Raul; Suri, Rajeev; Dalsaso, Timothy

    2011-01-01

    Pseudoaneurysms and aneurysms are abnormal dilatations of the vessel lumen. Pseudoaneurysm is a perfused hematoma contained by the adventitia and perivascular tissues that is in communication with the lumen of an adjacent artery or vein. Aneurysm is a dilatation of the vessel lumen involving all three layers of the blood vessel wall. Renal artery aneurysms (RAA) are uncommon but the widespread use of cross-sectional imaging and incidental detection of RAA may result in an increasing number of cases diagnosed. Renal artery pseudoaneurysms are suspected in bleeding patients after penetrating renal trauma. Imaging plays a major role in the detection of renal pseudoaneurysms and aneurysms and diagnoses aneurysm rupture and active bleeding. Computed tomography (CT), magnetic resonance imaging, and digital subtraction angiography can characterize lesion size, shape, and location and identify other aneurysms and pseudoaneurysms, helping to narrow the differential diagnosis and to understand the vascular anatomy for guiding proper treatment. Endovascular treatments have contributed considerably in the management of renal pseudoaneurysms and aneurysms. The use of coil embolization or covered stent placement prevents the mortality and mobility of surgery. The article describes imaging features and the endovascular therapies to treat these vascular processes and their possible complications. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. 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.

  19. 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.

  20. 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 ...

  1. Huge traumatic pulmonary artery pseudoaneurysm.

    PubMed

    Shnayderman, Dmitriy; Baginski, Scott G; Lea, William B; Erickson, Scott J

    2017-09-01

    Pulmonary artery pseudoaneurysm is a very rare complication of penetrating thoracic trauma. We present a case of a 27-year-old woman who developed a 6.5-cm traumatic pulmonary artery pseudoaneurysm after suffering multiple stab wounds to the chest and the abdomen. The pseudoaneurysm was successfully treated endovascularly with vascular plug occlusion and coil embolization.

  2. Cervical internal carotid artery pseudoaneurysm complicating malignant otitis externa: first case report.

    PubMed

    Baker, Andrew; Rizk, Habib; Carroll, William; Lambert, Paul

    2015-03-01

    Pseudoaneurysm of the internal carotid artery (ICA) is a rare complication of head and neck infections. To date, three cases of petrous ICA pseudoaneurysm have been described as a complication of otogenic infection, including only one secondary to malignant otitis externa. We present here the first case of cervical ICA pseudoaneurysm as a complication of malignant otitis externa, and stress the importance of timely diagnosis to avoid fatal outcomes. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  3. 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.

  4. Multiple hereditary exostoses: A pseudoaneurysm masquerading as tumor.

    PubMed

    Trivedi, Hari; Link, Thomas M; O'Donnell, Richard J; Horvai, Andrew E; Motamedi, Daria

    2016-08-01

    Multiple hereditary exostoses is an autosomal dominant condition characterized by numerous benign osteochondromas. Complications are rare and can include deformity, growth abnormality, fracture, adventitial bursa formation, local mass effect on a nerve, malignant degeneration, and vascular complications including stenosis, occlusion, arteriovenous fistula, and pseudoaneurysm. We present a case of multiple hereditary exostoses leading to a deep femoral artery pseudoaneurysm in the proximal medial thigh with subsequent rupture and hematoma, masquerading as tumor.

  5. 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.

  6. 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.

  7. 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.

  8. Pseudoaneurysm after arthroscopic procedure in the knee☆

    PubMed Central

    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. PMID:26229905

  9. 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.

  10. 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...

  11. 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...

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Secondary structure formation in peptide amphiphile micelles

    NASA Astrophysics Data System (ADS)

    Tirrell, Matthew

    2012-02-01

    Peptide amphiphiles (PAs) are capable of self-assembly into micelles for use in the targeted delivery of peptide therapeutics and diagnostics. PA micelles exhibit a structural resemblance to proteins by having folded bioactive peptides displayed on the exterior of a hydrophobic core. We have studied two factors that influence PA secondary structure in micellar assemblies: the length of the peptide headgroup and amino acids closest to the micelle core. Peptide length was systematically varied using a heptad repeat PA. For all PAs the addition of a C12 tail induced micellization and secondary structure. PAs with 9 amino acids formed beta-sheet interactions upon aggregation, whereas the 23 and 30 residue peptides were displayed in an apha-helical conformation. The 16 amino acid PA experienced a structural transition from helix to sheet, indicating that kinetics play a role in secondary structure formation. A p53 peptide was conjugated to a C16 tail via various linkers to study the effect of linker chemistry on PA headgroup conformation. With no linker the p53 headgroup was predominantly alpha helix and a four alanine linker drastically changed the structure of the peptide headgroup to beta-sheet, highlighting the importance of hydrogen boding potential near the micelle core.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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

  3. Endovascular treatment of hemodialysis access pseudoaneurysms.

    PubMed

    Shah, Aamir S; Valdes, Jaime; Charlton-Ouw, Kristofer M; Chen, Zhongxue; Coogan, Sheila M; Amer, Hammad M; Estrera, Anthony L; Safi, Hazim J; Azizzadeh, Ali

    2012-04-01

    Pseudoaneurysm (PSA) formation is a complication of hemodialysis access. Open repair requires PSA resection, interposition graft placement, and insertion of a catheter as a bridge. Endovascular stent graft repair is an alternative that permits immediate use of the access site. The objective of this study was to determine the efficacy of stent grafts for repair of arteriovenous fistula and arteriovenous graft PSA. A retrospective review of medical records from October 2007 to March 2011 revealed 24 patients with a PSA who underwent endovascular repair using a stent graft. Indications for repair included PSA with symptoms (n = 11), PSA with skin erosion (n = 8), PSA with failed hemodialysis (n = 3), and PSA after balloon angioplasty of a stenosis (n = 2). Outcome measures were technical success, 30-day and 180-day patency, secondary interventions, and complications. All the statistical analyses were conducted by using software SAS 9.1 (SAS, SAS Institute, Gary, NC). Twenty-seven self-expanding stent grafts (Viabahn, W. L. Gore, n = 25; Fluency, Bard, n = 2) were used to treat hemodialysis access (arteriovenous graft, n = 13; arteriovenous fistula, n = 11) PSA in 24 patients (16 females; mean age, 55.7 years; mean body mass index, 28.4; mean PSA diameter, 19.5 mm). Comorbidities included hypertension (n = 22; 91.7%), diabetes mellitus (n = 8; 33.3%), and coronary artery disease (n = 4; 16.67%). The median time from access creation to repair was 455 days. The technical success rate was 100%. Balloon angioplasty of an outflow stenosis was performed in 56% of stent grafts. The 30- and 180-day patency rate was 100% and 69.2%, respectively. Three secondary interventions were performed for treatment of unrelated stenosis. Treatment failure occurred in five (18.5%) stent grafts due to infection (n = 3) and thrombosis (n = 2). Treatment of PSA with skin erosion was associated with failure due to infection (odds ratio, 5.0; 95% confidence interval, .38, 66.01). The remaining

  4. 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

  5. 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.

  6. 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.

  7. Transcriptional control of secondary growth and wood formation.

    Treesearch

    Juan Du; Andrew Groover

    2010-01-01

    Secondary growth and wood formation are products of the vascular cambium, a lateral meristem. Although the mechanisms have only recently begun to be uncovered, transcriptional regulation appears increasingly central to the regulation of secondary growth. The importance of transcriptional regulation is illustrated by the correlation of expression of specific classes of...

  8. 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.

  9. 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.

  10. 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.

  11. Hereditary Multiple Exostoses with Pseudoaneurysm

    SciTech Connect

    Al-Hadidy, Azmy M. Al-Smady, Moa'ath M.; Haroun, Azmi A.; Hamamy, Hanan A.; Ghoul, Suha M.; Shennak, Akram O.

    2007-06-15

    A 16-year-old male patient with hereditary multiple exostoses (HME) was found to have a pseudoaneurysm of the left popliteal artery caused by osteochondroma in the lower femur. The diagnosis was confirmed by ultrasound, magnetic resonance imaging and magnetic resonance angiography without the need to perform an angiogram. The osteochondroma was excised and the popliteal artery was repaired with a saphenous graft. Vascular complications are extremely rare in HME, pseudoaneurysm being the most common and mostly located in the popliteal artery. This complication should be considered in young HME patients with a mass at the knee region. The radiological spectrum of investigations allows the diagnosis of this complication with proper and less invasive management procedures for the patient.

  12. On the Secondary Eyewall Formation of Hurricane Edouard (2014)

    NASA Technical Reports Server (NTRS)

    Abarca, Sergio F.; Montgomery, Michael T.; Braun, Scott A.; Dunion, Jason

    2016-01-01

    A first observationally-based estimation of departures from gradient wind balance during secondary eyewall formation is presented. The study is based on the Atlantic Hurricane Edouard (2014). This storm was observed during the National Aeronautics and Space Administrations (NASA) Hurricane and Severe Storm Sentinel (HS3) experiment, a field campaign conducted in collaboration with the National Oceanic and Atmospheric Administration (NOAA). A total of 135 dropsondes are analyzed in two separate time periods: one named the secondary eyewall formation period and the other one referred to as the decaying-double eyewalled storm period. During the secondary eyewall formation period, a time when the storm was observed to have only one eyewall, the diagnosed agradient force has a secondary maxima that coincides with the radial location of the secondary eyewall observed in the second period of study. The maximum spin up tendency of the radial influx of absolute vertical vorticity is within the boundary layer in the region of the eyewall of the storm and the spin up tendency structure elongates radially outward into the secondary region of supergradient wind, where the secondary wind maxima is observed in the second period of study. An analysis of the boundary layer averaged vertical structure of equivalent potential temperature reveals a conditionally unstable environment in the secondary eyewall formation region. These findings support the hypothesis that deep convective activity in this region contributed to spin up of the boundary layer tangential winds and the formation of a secondary eyewall that is observed during the decaying-double eyewalled storm period.

  13. Transcriptional regulation of secondary growth and wood formation.

    PubMed

    Du, Juan; Groover, Andrew

    2010-01-01

    Secondary growth and wood formation are products of the vascular cambium, a lateral meristem. Although the mechanisms have only recently begun to be uncovered, transcriptional regulation appears increasingly central to the regulation of secondary growth. The importance of transcriptional regulation is illustrated by the correlation of expression of specific classes of genes with related biological processes occurring at specific stages of secondary growth, including cell division, cell expansion, and cell differentiation. At the same time, transcription factors have been characterized that affect specific aspects of secondary growth, including regulation of the cambium and differentiation of cambial daughter cells. In the present review, we summarize evidence pointing to transcription as a major mechanism for regulation of secondary growth, and outline future approaches for comprehensively describing transcriptional networks underlying secondary growth.

  14. 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

  15. Engineering the formation of secondary building blocks within hollow interiors.

    PubMed

    Li, Xiaobo; Liu, Xiao; Ma, Yi; Li, Mingrun; Zhao, Jiao; Xin, Hongchuan; Zhang, Lei; Yang, Yan; Li, Can; Yang, Qihua

    2012-03-15

    Secondary building blocks within the cavities of primary silica-architecture building blocks are successfully engineered. The immobilized surfactant directs the selective dissolution and reassembly of dissolved silicate species for the formation of secondary building blocks (hollow nanospheres/nanorods; see figure). Supported TiO(2) on nanostructures with multilevel interiors is shown to exhibit significantly enhanced activity in photocatalytic H(2) production. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. [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.

  17. 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.

  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. Treatment of a Urinoma and a Post-Traumatic Pseudoaneurysm Using Selective Arterial Embolization

    SciTech Connect

    Pinto, Isabel T.; Chimeno, Paloma C.

    1998-11-15

    We report a case of severe renal trauma giving rise to a pseudoaneurysm of a renal branch artery and a large urinoma secondary to fracture of a calix disconnected from the rest of the collecting system. Both conditions were successfully treated using selective arterial embolization.

  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. 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...

  2. A Review of Secondary Organic Aerosol (SOA) Formation from Isoprene

    EPA Science Inventory

    Recent field and laboratory evidence indicates that the oxidation of isoprene forms secondary organic aerosol (SOA). Global biogenic emissions of isoprene (600 Tg yr-1) are sufficiently large the formation of SOA is even small yields results in substantial production ...

  3. 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...

  4. 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.

  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. Posttraumatic versus Mycotic Dorsalis Pedis Pseudoaneurysm.

    PubMed

    Lynch, James E; Winkler, Katrina A; Xenos, Eleftherios

    2013-06-01

    Reports of dorsalis pedis aneurysms are rare, and there are currently no reports of mycotic dorsalis pedis aneurysms in the literature. Most dorsalis pedis pseudoaneurysms are diagnosed by physical exam and color flow duplex. Surgical treatment includes aneurysm resection with or without reconstruction of the dorsalis pedis artery. We report a dorsalis pedis pseudoaneurysm diagnosed clinically and via duplex ultrasound, treated by excision and ligation of the aneurysm.

  7. 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

  8. Spontaneous resolution of superior medial geniculate artery pseudoaneurysm following total knee arthroplasty.

    PubMed

    Gaheer, Rajinder Singh; Chirputkar, Kedar; Sarungi, Martin

    2014-03-01

    Vascular injury after total knee arthroplasty is a rare event with significant morbidity. To date there are a handful of cases of pseudoaneurysms affecting the popliteal artery and cases involving one of the geniculate arteries are even rarer. Most case reports involving injuries to the geniculate vessels have reported surgical intervention to treat the condition. We report a case where injury to the superior medial geniculate artery with formation of pseudoaneurysm resolved without any surgical intervention. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. 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

  10. 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.

  11. Pseudoaneurysm after ICD battery replacement.

    PubMed

    Schulz, S L; Lehmkuhl, H; Zipfel, K B; Hetzer, R

    2007-02-01

    False aneurysms of the extracranial carotid arteries are rare and mainly of traumatic origin. We report on a patient who presented with a sudden onset mass in his right neck 2 weeks after routine replacement of his ICD battery. He had received systemic anticoagulation since an aortic valve replacement 5 years before. By color Doppler sonography the mass was identified as a partly thrombosed false aneurysm originating from the common carotid artery. As no spontaneous resolution occurred during the following days the aneurysm was removed surgically 5 days later without further complications. However no connection to the common carotid artery was found at surgery. Yet in the histopathological examination the specimen showed the morphological characteristics of a pseudoaneurysm. There was no history of neck-trauma and no attempted vascular access during the recent operation.

  12. Pseudoaneurysm of the left ventricle.

    PubMed Central

    Mackenzie, J W; Lemole, G M

    1994-01-01

    Pseudoaneurysm of the left ventricle most often occurs after transmural myocardial infarction but may also follow cardiac operations, trauma, inflammation, or infection. In contrast to patients with true ventricular aneurysm, those with false aneurysm most commonly die of hemorrhage. Review of the reported surgical experience and of our 14 cases confirms that standard chest radiographs with an abnormal cardiac silhouette and rapidly expanding size may alert the physician to this sometimes overlooked diagnosis. Noninvasive tests such as color-flow Doppler echocardiography, 2-dimensional echocardiography, cineangiographic computed tomography, and transesophageal echocardiography allow relatively easy recognition of these apparently rare lesions with increasing frequency. Cardiac catheterization, however, is usually still necessary for a clear picture of the location and anatomy of the aneurysm and the state of the coronary arteries. Finally, a new classification is proposed, consisting of true aneurysm, false aneurysm, pseudo-false aneurysm, and mixed aneurysm. Images PMID:7888805

  13. A benign gastric ulcer eroding into a splenic artery pseudoaneurysm presenting as a massive upper gastrointestinal bleed

    PubMed Central

    Syed, Shareef M.; Moradian, Simon; Ahmed, Mohammed; Ahmed, Umair; Shaheen, Samuel; Stalin, Vasanth

    2014-01-01

    Upper gastrointestinal (UGI) bleeding secondary to a ruptured splenic artery (SA) pseudoaneurysm into the stomach is a rare but a life-threatening condition. Owing to the low prevalence, it remains a diagnostic and therapeutic challenge. A frail 77-year-old Caucasian female presented with epigastric pain and hematemesis. Endoscopy was non-diagnostic for an etiology. She then underwent diagnostic angiography that revealed an SA pseudoaneurysm with active contrast extravasation into the stomach. Subsequent transcatheter arterial coil embolization was conducted of the SA. The patient was subsequently taken for a partial gastrectomy, distal pancreatectomy and splenectomy. She had an uncomplicated postoperative course. Diagnosis of an UGI bleeding secondary to a ruptured SA pseudoaneurysm into the stomach remains difficult. However, we report that in a hemodynamically stable patient, a multidisciplinary approach can be taken, with interval optimization of the patient prior to definitive surgery for a satisfactory outcome. PMID:25413998

  14. Kinetic regimes for formation and aging of secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Shiraiwa, Manabu; Berkemeier, Thomas; Schilling-Fahnestock, Katherine; Seinfeld, John; Pöschl, Ulrich

    2014-05-01

    Here we present a conceptual framework of kinetic regime and limiting cases for formation and aging of secondary organic aerosol (SOA). The limiting step of SOA formation can be identified following the developed classification scheme, which is based on three fundamental properties of oxidation products: the reaction location, the saturation ratio, and the heterogeneity in the gas and particle phases. Using the kinetic multi-layer model of gas-particle interactions (KM-GAP) (Shiraiwa et al., 2012), we have analyzed the experimental data of photooxidation of dodecane and subsequent SOA formation. We have found that the contribution of intermediate gas-phase oxidation products to SOA formation is most likely limited by gas-phase reaction, validating the assumption of instantaneous equilibrium partitioning. For semi-volatile and low volatility gas-phase oxidation products, partitioning into the particle phase can be limited by surface accommodation, and possibly by bulk diffusion when organic aerosols adopt glassy or amorphous solid state. The formation of low volatility particle-phase products, such as oligomers and other high molar mass compounds, may be limited by reaction and diffusion in the particle. The 2D evolution plot of molar mass vs. volatility is useful to overview SOA formation and aging. The average molar mass of the organic compounds can be used as a yardstick to estimate relative contribution of gas- vs. particle-phase chemistry to SOA formation. The relatively high values of measured average molar mass for ambient and laboratory-generated SOA imply the importance of particle-phase chemistry in SOA formation.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. Traumatic brachiocephalic pseudoaneurysm presenting as stroke in a seventeen-year-old.

    PubMed

    Kanwar, Manreet; Desai, Devang; Joumaa, Mouhammed; Guduguntla, Vamshidhar

    2009-11-01

    We present a 17-y-old male who presented to the emergency room with left arm weakness along with slurred speech. On physical examination, he had stable vital signs with left facial weakness suggestive of lower motor neuron seventh nerve palsy. He was also noted to have a small pulsatile mass in the right infraclavicular region. Further questioning revealed that 3 mo earlier he had suffered blunt chest wall trauma during a football game with fracture-dislocation of the right clavicular head, which was managed conservatively. MRI of the brain showed right frontal cortical changes suggestive of infarct versus vasculitis or edema. Chest CT revealed a 2.5- to 3-cm pseudoaneurysm arising from the brachiocephalic artery, with thrombus formation, along with a surrounding 3 x 4.5 cm hematoma. The patient underwent a successful repair of the pseudoaneurysm with no further neurological sequelae. Traumatic pseudoaneurysm with thrombus formation is an extremely rare cause of stroke. It has been reported in association with the carotid artery, but to our knowledge, this is the first reported case with isolated innominate artery pseudoaneurysm. This case highlights the need for a broad differential when evaluating young patients with neurological deficits.

  20. 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.

  1. Reducing secondary organic aerosol formation from gasoline vehicle exhaust.

    PubMed

    Zhao, Yunliang; Saleh, Rawad; Saliba, Georges; Presto, Albert A; Gordon, Timothy D; Drozd, Greg T; Goldstein, Allen H; Donahue, Neil M; Robinson, Allen L

    2017-07-03

    On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This suggests that the natural replacement of older vehicles with newer ones that meet more stringent emissions standards should reduce SOA levels in urban environments. However, SOA production depends on both precursor concentrations (emissions) and atmospheric chemistry (SOA yields). We found a strongly nonlinear relationship between SOA formation and the ratio of nonmethane organic gas to oxides of nitrogen (NOx) (NMOG:NOx), which affects the fate of peroxy radicals. For example, changing the NMOG:NOx from 4 to 10 ppbC/ppbNOx increased the SOA yield from dilute gasoline vehicle exhaust by a factor of 8. We investigated the implications of this relationship for the Los Angeles area. Although organic gas emissions from gasoline vehicles in Los Angeles are expected to fall by almost 80% over the next two decades, we predict no reduction in SOA production from these emissions due to the effects of rising NMOG:NOx on SOA yields. This highlights the importance of integrated emission control policies for NOx and organic gases.

  2. Fatal Traumatic Subarachnoid Hemorrhage due to Acute Rebleeding of a Pseudoaneurysm Arising from the Distal Basilar Artery.

    PubMed

    Kim, Byung Chul; Lee, Jae Il; Cho, Won Ho; Nam, Kyoung Hyup

    2014-11-01

    Isolated traumatic pseudoaneurysms of the basilar artery are extremely rare but often fatal resulting in a mortality rate as high as 50%. A 51-year-old man presented with craniofacial injury after blunt trauma. A brain computed tomography (CT) scan showed thick basal subarachnoid hemorrhage associated with multiple craniofacial fractures, while CT angiography revealed contrast extravasation at the distal basilar artery with pseudoaneurysm formation. After this primary survey, the condition of the patient suddenly deteriorated. Conventional angiography confirmed the contrast extravasation resulted from pseudoaneurysm formation, which was successfully treated with endovascular coil embolization. Decompressive craniectomy and coma therapy with propofol were also performed. However, the patient died on the 7th hospital day because of the poor initial clinical condition. The current case is the first report of acute pseudoaneurysm rupture arising from the basilar artery within the first day after trauma. Our findings suggest the possibility that pseudoaneurysm rupture should be considered if brain CT shows thick traumatic subarachnoid hemorrhage on the basal cistern with a basal skull fracture.

  3. Endovascular Repair of a Traumatic Axillary Pseudoaneurysm Following Anterior Shoulder Dislocation

    SciTech Connect

    Stahnke, Michaela; Duddy, Martin J.

    2006-04-15

    Pseudoaneurysms due to musculoskeletal trauma are rare and comprise less than 2% of all pseudoaneurysms. We report a case of axillary pseudoaneurysm following anterior dislocation of the shoulder. The patient was successfully treated by endovascular intervention.

  4. Formation and stability of secondary structures in globular proteins

    NASA Astrophysics Data System (ADS)

    Bascle, J.; Garel, T.; Orland, H.

    1993-02-01

    We study two models for the formation and packing of helices and sheets in globular (compact) proteins. These models, based on weighted Hamiltonian paths on a regular lattice both exhibit a first order transition between a compact high temperature phase, with no extended secondary structures, and a quasi-frozen compact phase, with secondary structures invading the whole lattice. The quasi-frozen phase with very weak temperature dependence, is identified as the native phase of proteins, whereas the high-temperature phase may be relevant to the so-called molten globule state of proteins. Nous étudions deux modèles pour la formation et l'empilement d'hélices ou de feuillets dans la phase globulaire (compacte) des protéines. ces modèles, fondés sur des chemins hamiltoniens pondérés sur réseau, possèdent une transition de phase du premier ordre, entre (i) une phase haute température compacte, avec structures secondaires non étendues, et (ii) une phase compacte quasi-gelée, où les structures secondaires envahissent tout le réseau. La phase quasi-gelée, qui a une dépendance en température très faible, est identifiée à la phase native des protéines; la phase haute température est peut-être reliée à la phase native “globule fondu” (molten globule) des protéines.

  5. 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.

  6. 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

  7. 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.

  8. Left ventricular pseudoaneurysm - a challenging diagnosis.

    PubMed

    Faustino, Mariana; Ranchordás, Sara; Abecasis, João; Freitas, António; Ferreira, Moradas; Gil, Victor; Morais, Carlos; Neves, José Pedro

    2016-06-01

    Left ventricular pseudoaneurysm is a rare complication of acute myocardial infarction, associated with high mortality. However, it can present in a non-specific manner, complicating and delaying the diagnosis. The authors present the case of a 65-year-old patient, hypertensive, with no other known relevant medical history, who presented with chest pain, cough and left pleural effusion, initially attributed to a pulmonary process. However, these were in fact the result of a left ventricular pseudoaneurysm following silent acute myocardial infarction. The diagnosis was suspected on echocardiography and confirmed by cardiac magnetic resonance imaging, and the patient underwent successful surgical pseudoaneurysm repair. This case illustrates an atypical presentation of a left ventricular pseudoaneurysm, in which the manifestations resulted from pericardial and pleural extension of the inflammatory process associated with contained myocardial rupture. The case demonstrates the need for a high index of suspicion, and the value of imaging techniques to confirm it, in order to proceed with appropriate surgical treatment, and thus modify the course of the disease. Copyright © 2015 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  9. 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.

  10. On the Dynamics of Hurricane Secondary Eyewall Formation

    NASA Astrophysics Data System (ADS)

    Martinez, Dr.; Brunet, Dr.; Yau, Dr.

    2009-04-01

    Despite the fact that asymmetries in hurricanes, such as spiral rainbands, polygonal eyewalls and mesovortices, have long been observed in radar imagery, many aspects of their dynamics still remain unsolved, particularly in the formation of the secondary eyewall. The underlying associated dynamical processes need to be better understood to advance the science of hurricane intensity forecasting. To fill this gap, a simple 2D barotropic "dry" model and the high-resolution PSU-NCAR non-hydrostatic mesoscale model (MM5) are used to study hurricane asymmetries. The Empirical Mormal Modes (ENM) and the newly developed Space-Time Empirical Normal Modes (ST-ENM) techniques, together with the Eliassen-Palm (EP) flux calculations, are used to isolate wave modes from the model datasets to investigate their impact on the changes in the structure and intensity of the simulated hurricanes. From the ENM diagnostics of the 2D simulations, it is shown that when asymmetric disturbances are placed outside a strong vortex ring with a large vorticity skirt they relax to form concentric rings of enhanced vorticity that contain a secondary wind maximum. The role of internal dynamics on Concentric Eyewall Genesis (CEG) is further evaluated using the full physics MM5 simulation. The leading modes of the ST-ENM diagnostics exhibit mainly characteristics of vortex Rossby waves (VRWs) and their contribution to the EP flux divergence induced two regions of maximum tangential wind acceleration; one inside the primary eyewall which accounts for eyewall contraction and the other outside the primary eyewall which explains the development of the secondary eyewall. A signal of maximum eddy angular momentum propagating outwards to the critical radius of the mode suggests a redistribution of angular momentum and potential vorticity re-arrangement around that area. The fact that the critical radius for some of the leading modes is close to the location where the secondary eyewall eventually develops

  11. 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...

  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. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Nonequilibrium atmospheric secondary organic aerosol formation and growth

    PubMed Central

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

    2012-01-01

    Airborne particles play critical roles in air quality, health effects, visibility, and climate. Secondary organic aerosols (SOA) formed from oxidation of organic gases such as α-pinene account for a significant portion of total airborne particle mass. Current atmospheric models typically incorporate the assumption that SOA mass is a liquid into which semivolatile organic compounds undergo instantaneous equilibrium partitioning to grow the particles into the size range important for light scattering and cloud condensation nuclei activity. We report studies of particles from the oxidation of α-pinene by ozone and NO3 radicals at room temperature. SOA is primarily formed from low-volatility ozonolysis products, with a small contribution from higher volatility organic nitrates from the NO3 reaction. Contrary to expectations, the particulate nitrate concentration is not consistent with equilibrium partitioning between the gas phase and a liquid particle. Rather the fraction of organic nitrates in the particles is only explained by irreversible, kinetically determined uptake of the nitrates on existing particles, with an uptake coefficient that is 1.6% of that for the ozonolysis products. If the nonequilibrium particle formation and growth observed in this atmospherically important system is a general phenomenon in the atmosphere, aerosol models may need to be reformulated. The reformulation of aerosol models could impact the predicted evolution of SOA in the atmosphere both outdoors and indoors, its role in heterogeneous chemistry, its projected impacts on air quality, visibility, and climate, and hence the development of reliable control strategies. PMID:22308444

  4. 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.

  5. Pseudoaneurysms of the Common Hepatic Artery Following Pancreaticoduodenectomy: Successful Emergency Embolization

    SciTech Connect

    Radeleff, Boris Noeldge, Gerd; Heye, Tobias; Schlieter, Martin; Friess, Helmut; Richter, Goetz M.; Kauffmann, Guenter W.

    2007-02-15

    We report a rare case of two communicating pseudoaneurysms of the common hepatic artery 1 month postoperatively following pylorus-preserving pancreaticoduodenectomy due an abscess formation. We describe the superselective transcatheteral embolization technique with deployment of interlocking detachable coils and Histoacryl-Lipiodol in this case and discuss the recent literature. Despite the technical success by achieving hemodynamic stability with initial preservation of liver function, the patient died 23 days postembolization due to multiorgan failure.

  6. 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

  7. [Femoral artery pseudoaneurysms encountered in orthopedics and traumatology].

    PubMed

    Raherinantenaina, F; Rajaonanahary, T M A; Rakoto Ratsimba, H N

    2015-12-01

    Most published articles regarding orthopedic- and trauma-related femoral artery pseudoaneurysms (FAPs) are case reports in English. Reported cases are often associated with a literature review but actually provide little robust data. We wanted to summarize the current knowledge on diagnostic and therapeutic features of these FAPs. A new case of superficial FAP is described followed by a review of the literature. A bibliographic search was performed online (PubMed, ScinceDirect) from 1964 to 2015 using the descriptors "traumatic femoral pseudoaneurysm, orthopedic surgery, osteochondroma". A total of 64 cases of FAPs was analyzed. There were 50 men with an average age of 40.72±26.45 years old. The most common clinical presentation was painful swelling (34%). Arteriography was the commonest radiological investigation used (63%). The main etiologies were orthopedic injuries (47%), surgery of the upper thigh (30%) and femoral osteochondromas (23%). Arterial injuries included superficial femoral (47%) and profunda femoris artery (50%). The treatment was open surgery (56%) or endovascular repair (36%). Deep femoral artery and its branches were embolized (47%) or ligated (38%). Endovascular stenting was performed in 30% of posttraumatic FAPs. All FAPs relating to osteochondromas were repaired surgically. Postoperative courses were uneventful in 95% of patients. Endovascular embolization is preferred in management of postsurgical FAPs which have usually involved the deep femoral artery. Endovascular stenting graft may be proposed for posttraumatic FAPs, for which the superficial femoral trunk is the most often involved vessel. Surgical repair should be performed when endovascular stenting graft is not feasible. Surgical repair is mandatory for all FAPs secondary to traumatic exostoses. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. 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

  9. [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.

  10. 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

  11. 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

  12. 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

  13. 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

  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. Management and outcome of hemorrhage due to arterial pseudoaneurysms in pancreatitis.

    PubMed

    Bergert, Hendrik; Hinterseher, Irene; Kersting, Stephan; Leonhardt, Johannes; Bloomenthal, Aaron; Saeger, Hans Detlev

    2005-03-01

    Arterial pseudoaneurysm formation in pancreatitis is a rare complication. The optimal treatment modality is controversial. Operative treatment and interventional treatment, either alone or as a temporizing method with a later operation, are options. In this single-center, patient-based cohort study, we managed 35 patients (8 with necrotizing pancreatitis and 27 with chronic pancreatitis) with bleeding pseudoaneurysms treated over a period of 10.5 years with a median follow-up of 4.6 years. Angiography was performed depending on the patient's hemodynamic condition. Angiography had a sensitivity of 96% for 26 patients. Angiographic embolization as primary treatment was performed in 16 patients (61% embolization rate); there were 2 rebleeding complications. No patients required intervention for embolization complications after discharge. Nineteen patients (54%) underwent an operation, 9 urgently without angiographic evaluation. The overall mortality rate for the 35 patients was 20% (19% for embolization, 21% after an operation). For necrotizing pancreatitis, an advantage of angiographic embolization was observed (mortality in 2/5 vs 2/3 after surgery). Ligation or repair of the bleeding vessel was complicated by higher rebleeding rates (6/13) than partial pancreatectomy (1/6). Concerns that angiographic embolization is unable to provide definitive hemostasis in both acute and chronic pancreatitis are unfounded. In the operative treatment of chronic pancreatitis, partial pancreatectomy is superior to vessel ligation, depending on the patient's general condition and degree of pancreatic inflammation. We propose an algorithm for the management of arterial pseudoaneurysms in the setting of pancreatitis.

  18. 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.

  19. 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.

  20. Pulmonary artery pseudoaneurysm after Swan-Ganz catheterization: a case presentation and review of literature.

    PubMed

    Nellaiyappan, Madhan; Omar, Hesham R; Justiz, Rafael; Sprenker, Collin; Camporesi, Enrico M; Mangar, Devanand

    2014-09-01

    The Swan-Ganz catheter for pulmonary artery (PA) cannulation was introduced in 1970 and has been utilized in the management of critically ill and cardiac patients. Although the routine use of this catheter has not been associated with better patient outcomes in prospective randomized trials, their ability to provide crucial hemodynamic measurements and the ease of bedside insertion makes them valuable in certain complex clinical scenarios. However, Swan-Ganz catheter insertion is not without complications. PA injury is the most serious complication suspected by the occurrence of hemoptysis after the procedure. We present a case of PA injury with pseudoaneurysm formation after Swan-Ganz catheterization along with a comprehensive review of literature. We reviewed all PubMed/Medline indexed articles published between 1993-2013, reporting the development of PA pseudoaneurysm after Swan-Ganz catheter use. Cases were analyzed with specific reference to patient demographics, indication for Swan-Ganz insertion, initial presenting symptom, duration between insertion and first evidence of PA injury, inciting event, site of pseudoaneurysm, treatment and outcome. Forty-one patients were identified from 27 papers. In the reviewed population, 87.8% were older than 60 years of age and 82.9% were females. Fifty-one percent of the patients had an episode of hemoptysis on the day of Swan-Ganz catheter insertion. Ninety-seven percent of the patients had PA pseudoaneurysm in the right pulmonary circulation. The admission-to-discharge mortality rate in the reviewed cohort was 15%. Cause of death in 22% of the cases was hemoptysis, while non-catheter related complications were responsible for the remaining deaths. PA injury is a feared complication after Swan-Ganz catheterization and can be fatal. In patients who develop massive or recurrent hemoptysis after Swan-Ganz catheter use, PA injury must be considered and airway protection should be employed along with appropriate catheter

  1. Interconnection of Salt-induced Hydrophobic Compaction and Secondary Structure Formation Depends on Solution Conditions

    PubMed Central

    Haldar, Shubhasis; Chattopadhyay, Krishnananda

    2012-01-01

    What happens in the early stage of protein folding remains an interesting unsolved problem. Rapid kinetics measurements with cytochrome c using submillisecond continuous flow mixing devices suggest simultaneous formation of a compact collapsed state and secondary structure. These data seem to indicate that collapse formation is guided by specific short and long range interactions (heteropolymer collapse). A contrasting interpretation also has been proposed, which suggests that the collapse formation is rapid, nonspecific, and a trivial solvent related compaction, which could as well be observed by a homopolymer (homopolymer collapse). We address this controversy using fluorescence correlation spectroscopy (FCS), which enables us to monitor the salt-induced compaction accompanying collapse formation and the associated time constant directly at single molecule resolution. In addition, we follow the formation of secondary structure using far UV CD. The data presented here suggest that both these models (homopolymer and heteropolymer) could be applicable depending on the solution conditions. For example, the formation of secondary structure and compact state is not simultaneous in aqueous buffer. In aqueous buffer, formation of the compact state occurs through a two-state co-operative transition following heteropolymer formalism, whereas secondary structure formation takes place gradually. In contrast, in the presence of urea, a compaction of the protein radius occurs gradually over an extended range of salt concentration following homopolymer formalism. The salt-induced compaction and the formation of secondary structure take place simultaneously in the presence of urea. PMID:22303014

  2. 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

  3. 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.

  4. 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

  5. Pulmonary Artery Pseudoaneurysm Related to Radiofrequency Ablation of Lung Tumor

    SciTech Connect

    Sakurai, Jun Mimura, Hidefumi; Gobara, Hideo; Hiraki, Takao; Kanazawa, Susumu

    2010-04-15

    We describe a case of pulmonary artery (PA) pseudoaneurysm related to radiofrequency ablation (RFA) of lung tumor. We performed RFA for a pulmonary epithelioid hemangioendothelioma directly adjacent to a branch of the PA. Seventeen days later, the patient complained of hemoptysis. A chest CT image revealed PA pseudoaneurysm. Transcatheter coil embolization was performed 59 days after RFA. Although PA pseudoaneurysm is rare, with an incidence of 0.2% (1/538 sessions) at our institution, it should be recognized as a risk when treating lung tumors adjacent to a branch of the PA.

  6. 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.

  7. 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.

  8. 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…

  9. 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…

  10. 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…

  11. 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…

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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

  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. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Hemobilia due to a cystic artery pseudoaneurysm on ultrasound.

    PubMed

    de Lara Bendahán, Victoria; García DomÍnguez, Encarna; Rivas Rivas, Marta; García Serrano, Jesús

    2017-09-07

    The present paper describes a case of hemobilia in a woman with a cystic artery pseudoaneurysm. The pseudoaneurysm could be seen with ultrasound, Doppler sonography and CT angiography. In our case, Doppler sonography was the most useful technique for diagnosis, revealing the turbulent forward and backwards flow within the gallbladder, representing the focally dilated artery. This was later confirmed by CT angiography. A recent bleeding site was found on the cholecystectomy specimen.

  1. Hemobilia due to a cystic artery pseudoaneurysm on ultrasound.

    PubMed

    de Lara Bendahán, Victoria; García DomÍnguez, Encarna; Rivas Rivas, Marta; García Serrano, Jesús

    2017-08-01

    The present paper describes a case of hemobilia in a woman with a cystic artery pseudoaneurysm. The pseudoaneurysm could be seen with ultrasound, Doppler sonography and CT angiography. In our case, Doppler sonography was the most useful technique for diagnosis, revealing the turbulent forward and backwards flow within the gallbladder, representing the focally dilated artery. This was later confirmed by CT angiography. A recent bleeding site was found on the cholecystectomy specimen.

  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. 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...

  4. 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…

  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. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. A benign gastric ulcer eroding into a splenic artery pseudoaneurysm presenting as a massive upper gastrointestinal bleed.

    PubMed

    Syed, Shareef M; Moradian, Simon; Ahmed, Mohammed; Ahmed, Umair; Shaheen, Samuel; Stalin, Vasanth

    2014-11-20

    Upper gastrointestinal (UGI) bleeding secondary to a ruptured splenic artery (SA) pseudoaneurysm into the stomach is a rare but a life-threatening condition. Owing to the low prevalence, it remains a diagnostic and therapeutic challenge. A frail 77-year-old Caucasian female presented with epigastric pain and hematemesis. Endoscopy was non-diagnostic for an etiology. She then underwent diagnostic angiography that revealed an SA pseudoaneurysm with active contrast extravasation into the stomach. Subsequent transcatheter arterial coil embolization was conducted of the SA. The patient was subsequently taken for a partial gastrectomy, distal pancreatectomy and splenectomy. She had an uncomplicated postoperative course. Diagnosis of an UGI bleeding secondary to a ruptured SA pseudoaneurysm into the stomach remains difficult. However, we report that in a hemodynamically stable patient, a multidisciplinary approach can be taken, with interval optimization of the patient prior to definitive surgery for a satisfactory outcome. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2014.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Secondary embryonic axis formation by transplantation of D quadrant micromeres in an oligochaete annelid.

    PubMed

    Nakamoto, Ayaki; Nagy, Lisa M; Shimizu, Takashi

    2011-01-01

    Among spiral cleaving embryos (e.g. mollusks and annelids), it has long been known that one blastomere at the four-cell stage, the D cell, and its direct descendants play an important role in axial pattern formation. Various studies have suggested that the D quadrant acts as the organizer of the embryonic axes in annelids, although this has never been demonstrated directly. Here we show that D quadrant micromeres (2d and 4d) of the oligochaete annelid Tubifex tubifex are essential for embryonic axis formation. When 2d and 4d were ablated the embryo developed into a rounded cell mass covered with an epithelial cell sheet. To examine whether 2d and 4d are sufficient for axis formation they were transplanted to an ectopic position in an otherwise intact embryo. The reconstituted embryo formed a secondary embryonic axis with a duplicated head and/or tail. Cell lineage analyses showed that neuroectoderm and mesoderm along the secondary axis were derived from the transplanted D quadrant micromeres and not from the host embryo. However, endodermal tissue along the secondary axis originated from the host embryo. Interestingly, when either 2d or 4d was transplanted separately to host embryos, the reconstituted embryos failed to form a secondary axis, suggesting that both 2d and 4d are required for secondary axis formation. Thus, the Tubifex D quadrant micromeres have the ability to organize axis formation, but they lack the ability to induce neuroectodermal tissues, a characteristic common to chordate primary embryonic organizers.

  18. Posttraumatic infrarenal abdominal aortic pseudoaneurysm treated with bifurcated endovascular graft stent

    PubMed Central

    Erkanli, Korhan; Akturk, Ibrahim Faruk; Aydin, Unal; Akinci, Okan; Yildirim, Aydin

    2015-01-01

    Posttraumatic infrarenal aortic pseudoaneurysms are rare and potentially lethal lesions. We report the case of a 32-year-old man presenting with infrarenal aortic pseudoaneurysm eight months after being stabbed in the back and right flank. His pseudoaneurysm was close to the iliac bifurcation, so we decided to deploy a bifurcated endovascular graft stent, the TriVascular Ovation endovascular stent. Imaging one month after the procedure revealed no endoleak and slight shrinkage of the pseudoaneurysm. PMID:26161108

  19. Post-traumatic hepatic artery pseudo-aneurysm combined with subphrenic liver abscess treated with embolization

    PubMed Central

    Sun, Long; Guan, Yong-Song; Wu, Hua; Pan, Wei-Min; Li, Xiao; He, Qing; Liu, Yuan

    2006-01-01

    A 23-year-old man with post-traumatic hepatic artery pseudo-aneurysm and subphrenic liver abscess was admitted. He underwent coil embolization of hepatic artery pseudo-aneurysm. The pseudo-aneurysm was successfully obstructed and subphrenic liver abscess was controlled. Super-selective trans-catheter coil embolization may represent an effective treatment for hepatic artery pseudo-aneurysm combined with subphrenic liver abscess in the absence of other therapeutic alternatives. PMID:16718774

  20. 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.

  1. Secondary Island Formation in Collisional and Collisionless Kinetic Simulations of Magnetic Reconnection

    SciTech Connect

    Daughton, W.; Roytershteyn, V.; Yin, L.; Albright, B. J.; Gary, S. P.; Karimabadi, H.; Bowers, Kevin J.

    2011-01-04

    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 play a key role in breaking away from the slow Sweet-Parker scaling and pushing the evolution towards small scales where kinetic effects can dominate. In the collisionless limit, fast reconnection can proceed in small systems (30x ion inertial scale) without producing any secondary islands. However, in large-scale systems the diffusion region forms extended current layers that are unstable to the formation of secondary islands, giving rise to a time-dependent reconnection process. These instabilities provide one possible mechanism for controlling the average length of the diffusion region in large systems. New results from Fokker-Planck kinetic simulations are used to examine the role of secondary islands in electron-positron plasmas for both collisional and kinetic parameter regimes. Simple physics arguments suggest the transition should occur when the resistive layers approach the inertial scale. These expectations are confirmed by simulations, which demonstrate the average rate remains fast in large systems and is accompanied by the continuous formation of secondary islands.

  2. Femoral artery pseudoaneurysm as a complication of angioplasty. How can it be prevented?

    PubMed Central

    Gupta, Prabha Nini; Salam Basheer, Abdul; Sukumaran, Gireesh Gomaty; Padmajan, Sabin; Praveen, Satheesan; Velappan, Praveen; Nair, Bigesh Unnikrishnan; Nair, Sandeep Govindan; Kunjuraman, Usha Kumari; Madthipat, Unnikrishnan; R, Jayadevan

    2013-01-01

    Femoral pseudoaneurysm is a common complication of repeated femoral puncture during cardiac catheterisation. We describe here the development of femoral pseudoaneurysms in a patient with Takayasu's arteritis, which healed in response to conservative treatment, and review the literature on the prevention and treatment of femoral pseudoaneurysm. PMID:27326111

  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. Hepatic Artery Pseudoaneurysm: Delayed Presentation after a Blunt Trauma

    PubMed Central

    Batur, Abdussamet; Yavuz, Alpaslan; Toktas, Osman; Bora, Aydın; Bulut, Mehmet Deniz

    2015-01-01

    Summary Background Ruptured hepatic artery pseudoaneurysm is a rare condition that is life-threatening if not diagnosed and treated rapidly. We present a case of a spontaneously ruptured hepatic artery pseudoaneurysm that occurred after a blunt trauma, and provide a review of the current literature on this topic. This case study demonstrates a spontaneously ruptured hepatic artery pseudoaneurysm which emerged following a blunt trauma and it also presents current literature studies on the topic. Case Report A man at the age of 34 years with blunt trauma dating back to 1.5 month was admitted to the emergency department of a hospital with hematemesis and epigastric tenderness. He also had a duodenal ulcer, blood in the gastric lumen and a large pseudoaneurysm that developed from the left hepatic artery. Soon after the diagnosis, the patient worsened and underwent distal gastrectomy and cholecystectomy that included removing the bleeding aneurysm. Conclusions Ruptured hepatic artery pseudoaneurysm stands as a deadly condition which has to be diagnosed and managed as soon as possible. Physicians need to take aneurysms of abdominal arteries into consideration after routine diagnostic practises as long as the cause of gastrointestinal haemorrhage is unidentified. PMID:26171087

  5. FASTR: A novel data format for concomitant representation of RNA sequence and secondary structure information.

    PubMed

    Bose, Tungadri; Dutta, Anirban; Mh, Mohammed; Gandhi, Hemang; Mande, Sharmila S

    2015-09-01

    Given the importance of RNA secondary structures in defining their biological role, it would be convenient for researchers seeking RNA data if both sequence and structural information pertaining to RNA molecules are made available together. Current nucleotide data repositories archive only RNA sequence data. Furthermore, storage formats which can frugally represent RNA sequence as well as structure data in a single file, are currently unavailable. This article proposes a novel storage format, 'FASTR', for concomitant representation of RNA sequence and structure. The storage efficiency of the proposed FASTR format has been evaluated using RNA data from various microorganisms. Results indicate that the size of FASTR formatted files (containing both RNA sequence as well as structure information) are equivalent to that of FASTA-format files, which contain only RNA sequence information. RNA secondary structure is typically represented using a combination of a string of nucleotide characters along with the corresponding dot-bracket notation indicating structural attributes. 'FASTR' - the novel storage format proposed in the present study enables a frugal representation of both RNA sequence and structural information in the form of a single string. In spite of having a relatively smaller storage footprint, the resultant 'fastr' string(s) retain all sequence as well as secondary structural information that could be stored using a dot-bracket notation. An implementation of the 'FASTR' methodology is available for download at http://metagenomics.atc.tcs.com/compression/fastr.

  6. 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.

  7. 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

  8. Ipsilateral jugular access to treat an otherwise inaccessible puncture-related arteriovenous fistula pseudoaneurysm: a technical note.

    PubMed

    Rabellino, Martin; Rosa-Diez, Guillermo; Peralta, Oscar; Shinzato, Sergio; Crucelegui, Maria Soledad; Serra, Diego; Garcia-Monaco, Ricardo

    2014-01-01

    The standard approach for the endovascular treatment of a dysfunctional or occluded hemodialysis access in the upper limbs includes a direct intervention through the access itself or alternatively, when not feasible, through the brachial or radial artery access. Nonetheless, there are certain circumstances in which these approaches are not easily achieved. An 89-year-old male with end-stage renal disease developed a pseudoaneurysm after an hemorrhagic complication of a recently transposed native basilic arteriovenous fistula secondary to a needle puncture. Dehiscence of the injured access with spontaneous arterial bleeding evolved as a consequence of the upper limb swelling, rendering therapeutic intervention of the access through a conventional route impossible. A fistulogram through puncture of the common femoral artery was performed to obtain an accurate diagnosis. However, this approach was insufficient to advance the covered stent with the intention of excluding the pseudoaneurysm, as the stent delivery system could not reach the desired site. Given that the covered stent insertion required a 9 Fr introducer, the radial artery approach was ruled out. Therefore, we chose a venous access via the ipsilateral internal jugular vein, which was punctured under ultrasound guidance. This strategy was useful to advance the stent and exclude the pseudoaneurysm successfully. This technique should be considered for those individuals in whom conventional routes of approach for repairing dialysis accesses are not feasible or are extremely risky.

  9. Modeling of formation and distribution of secondary aerosols in the Milan area (Italy)

    NASA Astrophysics Data System (ADS)

    Andreani-Aksoyoglu, S.; PréVôT, A. S. H.; Baltensperger, U.; Keller, J.; Dommen, J.

    2004-03-01

    The performance of an aerosol module of the three-dimensional Eulerian model CAMx (Comprehensive Air Quality Model with Extensions) was evaluated in a domain covering the Po Basin in northern Italy. Concentrations of secondary aerosol species such as particulate NO3-, NH4+, SO42-, and SOC (secondary organic carbon) were calculated for the particle size below 2.5 μm and compared with the data available from a field experiment, which took place in May-June 1998. Model results for the inorganic aerosols were comparable to the measurements at an urban and a rural station. Sensitivity studies with reduced anthropogenic NOx and volatile organic carbon (VOC) emissions showed that SOC behaves in the same way as ozone, i.e., decreases with reduced VOC emissions and increases with reduced NOx emissions in the plume where ozone production is predicted to be VOC sensitive. Sensitivity of secondary aerosol formation to NH3 and NOx emissions was studied by reducing these emissions. Varying NH3 emissions led to an almost linear change in secondary aerosol mass at sites with low NH3. At ammonia-rich sites, on the other hand, availability of nitrate became important for the further formation of secondary aerosols. Monoterpene emissions were predicted to contribute about 25% of the secondary organic aerosols produced in the northern part of the model domain, which is mostly a forested area.

  10. 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…

  11. 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…

  12. 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...

  13. 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...

  14. 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.

  15. Iatrogenic pseudoaneurysm following reverse radial forearm free tissue transfer.

    PubMed

    Baynosa, Richard C; Echo, Anthony; Hovsepian, Raffi V; Zamboni, William A

    2007-08-01

    The appearance of a pseudoaneurysm in a free flap is an extremely rare complication in microsurgery. Yet, although uncommon, this occurrence still poses a dilemma as to the most effective mode of treatment. Treatment modalities consist of surgical exploration, embolization, and endovascular stenting. We present a case of arterial pedicle pseudoaneurysm following free tissue transfer of a radial forearm flap for a cranial defect. We describe our successful operative treatment of the pseudoaneurysm as well as review the literature regarding the applicability of the described treatments. We conclude that a critical evaluation of factors including the timing of arterial inflow loss, the necessity of the pedicle, the condition and quality of the recipient site, and the possibility of neovascularization can assist in determining the proper intervention and maximizing success.

  16. [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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Technical strategy for the endovascular management of ascending aortic pseudoaneurysm.

    PubMed

    Gray, Bruce H; Langan, Eugene M; Manos, Ginger; Bair, Leah; Lysak, Steven Z

    2012-07-01

    We present two cases of ascending aortic pseudoaneurysm exclusion with off-the-shelf aortic stent grafts. The right common carotid artery was used for access to facilitate graft delivery. Control of graft deployment was aided using a compliant right atrial occlusion balloon to lower cardiac output at the time of deployment. Transesophageal echocardiography facilitated the sizing and positioning of the right atrial balloon and was used to survey the heart and ascending aorta on successful exclusion of the pseudoaneurysm. These simple maneuvers made an uncommon procedure straight forward, predictable, and successful. Copyright © 2012 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    PubMed Central

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  8. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    PubMed

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  9. 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.

  10. 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

  11. Factors determining the formation of secondary inorganic aerosol: a case study in the Po Valley (Italy)

    NASA Astrophysics Data System (ADS)

    Squizzato, S.; Masiol, M.; Brunelli, A.; Pistollato, S.; Tarabotti, E.; Rampazzo, G.; Pavoni, B.

    2013-02-01

    Physicochemical properties of aerosol were investigated by analyzing the inorganic water soluble content in PM2.5 samples collected in the eastern part of the Po Valley (Italy). In this area the EU limits for many air pollutants are frequently exceeded as a consequence of local sources and regional-scale transport of secondary inorganic aerosol precursors. Nine PM2.5-bound major inorganic ions (F-, Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+, Ca2+) were monitored over one year in three sites categorized as semi-rural background, urban background and industrial. The acidic properties of the PM2.5 were studied by applying the recently developed E-AIM thermodynamic model 4 (Extended Aerosol Thermodynamics Model). The experimental data were also examined in relation to the levels of gaseous precursors of secondary inorganic aerosol (SO2, NOx, NO, NO2) and on the basis of some environmental conditions having an effect on the secondary aerosols generation processes. A chemometric procedure using cluster analysis on experimental [NH4+]/[SO42-] molar ratio and NO3- concentration has been applied to determine the conditions needed for ammonium nitrate formation in different chemical environments. Finally, some considerations on the secondary inorganic aerosol formation and the most relevant weather conditions concerning the sulfate-nitrate-ammonium system were also discussed. The obtained results and discussion can help in understanding the secondary aerosol formation dynamics in the Po Valley, which is one of the most critical regions for air pollution in southern Europe.

  12. 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.

  13. 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.

  14. 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.

  15. Fly ash-mediated formation of polychlorinated naphthalenes during secondary copper smelting and mechanistic aspects.

    PubMed

    Jiang, Xiaoxu; Liu, Guorui; Wang, Mei; Zheng, Minghui

    2015-01-01

    Thermal experiments (at 250-450 °C for 10-240 min) on fly ash from secondary copper smelting process (SeCu) were performed to study the polychlorinated naphthalene (PCN) formation in the post-zone of a secondary copper smelter. Unexpectedly high concentrations of PCNs were formed. Total PCN concentrations and toxic equivalents were 47-104 and 44-80 times higher than the initial concentration and toxic equivalent, respectively. The thermal disposal of SeCu fly ash should therefore be reconsidered. The kinetic of each homolog was determined under different thermal conditions. Less chlorinated homologs favored 350 °C and more chlorinated homologs favored higher temperature. Most of the homologs reached an equilibrium of formation and degradation within 30 min, except octachloronaphthalene which did not appear to reach such an equilibrium even after 240 min. Chlorine substitution of the formed PCNs was identified and a similar pattern was found in chlorination products starting with naphthalene and chlorine. Furthermore, inorganic chlorine and unsubstituted naphthalene were found in the reaction products, confirming that the formation of naphthalene and the chlorination of that naphthalene could occur and could be suggested to be an important PCN formation route. A detailed formation pathway from naphthalene through octachloronaphthalene is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Anastomotic pseudoaneurysms. A continuing late complication of vascular reconstructive procedures.

    PubMed

    Dennis, J W; Littooy, F N; Greisler, H P; Baker, W H

    1986-03-01

    Anastomotic pseudoaneurysms continue to be a late complication of vascular grafting procedures. We reviewed the records of 48 patients who presented with 65 abdominal or lower extremity anastomotic pseudoaneurysms during 1977 to 1985. The interval between the original operation and the development of a pseudoaneurysm was 6.2 years (range, 2.5 months to 19 years). Most patients underwent resection of the involved segment of graft and artery with placement of an interposition graft. Graft patency was 97.5% during a mean follow-up of 2.4 years (range, two months to five years), and one operative mortality occurred. Four patients had emergency procedures; one patient underwent reconstruction, and three others underwent resection of the pseudoaneurysms alone. Two of those patients died, and the one survivor eventually required a high amputation. We recommend aggressive diagnosis and surgical reconstruction in these patients usually by interposition grafts or anastomotic revisions because the short- and long-term results are excellent. Morbidity and mortality are greatly increased when these procedures are done emergently.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary aerosol formation

    NASA Astrophysics Data System (ADS)

    Carter, William P. L.; Cocker, David R.; Fitz, Dennis R.; Malkina, Irina L.; Bumiller, Kurt; Sauer, Claudia G.; Pisano, John T.; Bufalino, Charles; Song, Chen

    A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m 3 FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled enclosure flushed with purified air. Solar radiation is simulated with either a 200 kW Argon arc lamp or multiple blacklamps. Results of initial characterization experiments, all carried out at ˜300-305 K under dry conditions, concerning NO x and formaldehyde offgasing, radical sources, particle loss rates, and background PM formation are described. Results of initial single organic-NO x and simplified ambient surrogate-NO x experiments to demonstrate the utility of the facility for mechanism evaluation under low NO x conditions are summarized and compared with the predictions of the SAPRC-99 chemical mechanism. Overall, the results of the initial characterization and evaluation indicate that this new environmental chamber can provide high quality mechanism evaluation data for experiments with NO x levels as low as ˜2 ppb, though the results indicate some problems with the gas-phase mechanism that need further study. Initial evaluation experiments for SOA formation, also carried out under dry conditions, indicate that the chamber can provide high quality secondary aerosol formation data at relatively low hydrocarbon concentrations.

  7. Adenomyomectomy, curettage, and then uterine artery pseudoaneurysm occupying the entire uterine cavity.

    PubMed

    Matsubara, Shigeki; Usui, Rie; Sato, Tomomi; Kuwata, Tomoyuki; Ohkuchi, Akihide; Nakata, Manabu

    2013-05-01

    Uterine artery pseudoaneurysm can occur after cesarean section or traumatic delivery, usually manifesting as postpartum hemorrhage. Pregnant women after adenomyomectomy sometimes suffer some adverse events, among which uterine rupture has been widely acknowledged. We describe a post-abortive woman who had uterine artery pseudoaneurysm occupying the entire uterine cavity. She underwent adenomyomectomy and became pregnant. She experienced a missed abortion and underwent evacuation and curettage, which caused bleeding. Several days later, ultrasound revealed an intrauterine mass with marked blood flow. Angiography revealed the un-ruptured left uterine artery pseudoaneurysm, with arterial embolization stopping the flow within the pseudoaneurysm. Adenomyomectomy with subsequent curettage was considered to have caused the pseudoaneurysm. We must be cautious that pseudoaneurysm may occur in post-abortive women after adenomyomectomy. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Predicting secondary organic aerosol formation from terpenoid ozonolysis with varying yields in indoor environments.

    PubMed

    Youssefi, S; Waring, M S

    2012-10-01

    The ozonolysis of terpenoids generates secondary organic aerosol (SOA) indoors. Models of varying complexity have been used to predict indoor SOA formation, and many models use the SOA yield, which is the ratio of the mass of produced SOA and the mass of consumed reactive organic gas. For indoor simulations, the SOA yield has been assumed as a constant, even though it depends on the concentration of organic particles in the air, including any formed SOA. We developed two indoor SOA formation models for single terpenoid ozonolysis, with yields that vary with the organic particle concentration. The models have their own strengths and were in agreement with published experiments for d-limonene ozonolysis. Monte Carlo analyses were performed, which simulated different residential and office environments to estimate ranges of SOA concentrations and yields for d-limonene and α-pinene ozonolysis occurring indoors. Results indicate that yields are highly variable indoors and are most influenced by background organic particles for steady-state formation and indoor ozone concentration for transient peak formation. Additionally, a review of ozonolysis yields for indoor-relevant terpenoids in the literature revealed much uncertainty in their values at low concentrations typical of indoors. The results in this study suggest important factors that govern indoor secondary organic aerosol (SOA) formation and yields, in typical residential and office spaces. This knowledge informs the development and comparison of control strategies to reduce indoor-generated SOA. The ranges of SOA concentrations predicted indoors allow the quantification of the effects of sorptive interactions of semi-volatile organic compounds or reactive oxygen species with SOA, filter loading owing to SOA formation, and impacts of SOA on health, if links are established. © 2012 John Wiley & Sons A/S.

  13. Emerging Trends in the Volume and Format of Outside Examinations Submitted for Secondary Interpretation

    PubMed Central

    Hunt, Christopher H.; Wood, Christopher P.; Diehn, Felix E.; Eckel, Laurence J.; Schwartz, Kara M.; Erickson, Bradley J.

    2014-01-01

    OBJECTIVE The purpose of this article is to describe the trends of secondary interpretations, including the total volume and format of cases. MATERIALS AND METHODS This retrospective study involved all outside neuroradiology examinations submitted for secondary interpretation from November 2006 through December 2010. This practice utilizes consistent criteria and includes all images that cover the brain, neck, and spine. For each month, the total number of outside examinations and their format (i.e., hard-copy film, DICOM CD-ROM, or non-DICOM CD-ROM) were recorded. RESULTS There was no significant change in the volume of cases (1043 ± 131 cases/month; p = 0.46, two-sided Student t test). There was a significant decrease in the volume of hard-copy films submitted, with the mean number of examinations submitted per month on hard-copy film declining from 297 in 2007 to 57 in 2010 (p < 0.0001, Student t test). This decrease was mirrored by an increase in the mean number of cases submitted on CD-ROM (753 cases/month in 2007 and 1036 cases/month in 2010; p < 0.0001). Although most were submitted in DICOM format, there was almost a doubling of the volume of cases submitted on non-DICOM CD-ROM (mean number of non-DICOM CD-ROMs, nine cases/month in 2007 and 17 cases/month in 2010; p < 0.001). CONCLUSION There has been a significant decrease in the number of hard-copy films submitted for secondary interpretation. There has been almost a doubling of the volume of cases submitted in non-DICOM formats, which is unfortunate, given the many advantages of the internationally derived DICOM standard, including ease of archiving, standardized display, efficient review, improved interpretation, and quality of patient care. PMID:22451538

  14. Surgical Treatment of Facial Artery Pseudoaneurysm Following Blunt Trauma: Report of a Case.

    PubMed

    Payami, Ali; Montazem, Andre H

    2017-02-01

    There are few reports of pseudoaneurysm of the facial artery in the literature and very little attention has been paid to their surgical management. Practitioners should be aware of this unusual complication of facial trauma and of the alternatives for treatment of pseudoaneurysms. Surgical resection of selective head and neck pseudoaneurysms provides a safe and effective method for the treatment of these vascular lesions. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  15. 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.

  16. Post-traumatic Cavernosal Artery Pseudoaneurysm Presenting as Right Hip Pain: An Imaging Evaluation.

    PubMed

    Govindarajan, Aarthi; Sai, P M Venkata; Anupama, C; Joseph, S Santosh

    2012-01-01

    Pseudoaneurysm of the cavernosal artery is quite rare. Herein, we describe color Doppler findings of post-traumatic pseudoaneurysm of the right cavernosal artery in a 19-year-old adolescent boy who presented with right hip pain. Doppler showed turbulence of flow with arterial inflow and outflow from the aneurysm. Selective transarterial catheterization of the internal iliac and internal pudental artery with microcatheter and embolization of pseudoaneurysm using histocryl resulted in alleviation of symptoms.

  17. 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

  18. Percutaneous Repair of Radial Artery Pseudoaneurysm in a Hemodialysis Patient Using Sonographically Guided Thrombin Injection

    SciTech Connect

    Corso, Rocco Rampoldi, Antonio; Vercelli, Ruggero; Leni, Davide; Vanzulli, Angelo

    2006-02-15

    We report a case of a radial artery pseudoaneurysm complicating an incorrect puncture of a Brescia-Cimino hemodialysis fistula that was treated with percutaneous ultrasound-guided thrombin injection. The pseudoaneurysm recurred after the initial successful thrombin injection. With a second injection we obtained permanent pseudoaneurysm occlusion. Our case illustrates that this procedure is an effective treatment in this type of arteriovenous fistula complication. We compare this case with the only similar one we could find in the literature.

  19. 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.

  20. 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.

  1. 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.

  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.; 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.

  3. 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.

  4. Exact calculation of loop formation probability identifies folding motifs in RNA secondary structures.

    PubMed

    Sloma, Michael F; Mathews, David H

    2016-12-01

    RNA secondary structure prediction is widely used to analyze RNA sequences. In an RNA partition function calculation, free energy nearest neighbor parameters are used in a dynamic programming algorithm to estimate statistical properties of the secondary structure ensemble. Previously, partition functions have largely been used to estimate the probability that a given pair of nucleotides form a base pair, the conditional stacking probability, the accessibility to binding of a continuous stretch of nucleotides, or a representative sample of RNA structures. Here it is demonstrated that an RNA partition function can also be used to calculate the exact probability of formation of hairpin loops, internal loops, bulge loops, or multibranch loops at a given position. This calculation can also be used to estimate the probability of formation of specific helices. Benchmarking on a set of RNA sequences with known secondary structures indicated that loops that were calculated to be more probable were more likely to be present in the known structure than less probable loops. Furthermore, highly probable loops are more likely to be in the known structure than the set of loops predicted in the lowest free energy structures. © 2016 Sloma and Mathews; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  5. 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.

  6. 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

  7. 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.

  8. Formation of wood secondary cell wall may involve two type cellulose synthase complexes in Populus.

    PubMed

    Xi, Wang; Song, Dongliang; Sun, Jiayan; Shen, Junhui; Li, Laigeng

    2017-03-01

    Cellulose biosynthesis is mediated by cellulose synthases (CesAs), which constitute into rosette-like cellulose synthase complexe (CSC) on the plasma membrane. Two types of CSCs in Arabidopsis are believed to be involved in cellulose synthesis in the primary cell wall and secondary cell walls, respectively. In this work, we found that the two type CSCs participated cellulose biosynthesis in differentiating xylem cells undergoing secondary cell wall thickening in Populus. During the cell wall thickening process, expression of one type CSC genes increased while expression of the other type CSC genes decreased. Suppression of different type CSC genes both affected the wall-thickening and disrupted the multilaminar structure of the secondary cell walls. When CesA7A was suppressed, crystalline cellulose content was reduced, which, however, showed an increase when CesA3D was suppressed. The CesA suppression also affected cellulose digestibility of the wood cell walls. The results suggest that two type CSCs are involved in coordinating the cellulose biosynthesis in formation of the multilaminar structure in Populus wood secondary cell walls.

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

    PubMed

    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 degrees 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 degrees 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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).

  18. 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.

  19. 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.

  20. 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

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

    PubMed

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

    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.

  2. 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.

  3. 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.

  4. Endovascular management of iatrogenic cervical internal carotid artery pseudoaneurysm in a 9-year-old child: Case report and literature review.

    PubMed

    Pinzón, Martín; Lobelo, Nelson Oswaldo; Rodríguez, María Claudia; Villamor, Perla; Otoya, Ana María

    2017-04-01

    Extracranial internal carotid artery (ICA) pseudoaneurysms are uncommon in the pediatric population and are usually secondary to direct trauma to the vessel. Treatment options include surgery (ligation), anticoagulation therapy and endovascular treatment. Endovascular covered stents have shown good results in adult populations, resulting in occlusion of the aneurysm and preservation of the artery without significant complications. However, there have been only limited reports in the literature reporting endovascular carotid stent placement in the pediatric population. We report a case of a 9-year-old boy patient, who developed a cervical ICA pseudoaneurysm after a parapharyngeal tumor resection. He was successfully treated by primary endovascular covered stent placement. During a follow-up of 6 months the patient has been asymptomatic, without any adverse event. Additionally, a literature review is done. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. 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

  6. Dynamics and predictability of secondary eyewall formation in sheared tropical cyclones

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqing; Tao, Dandan; Sun, Y. Qiang; Kepert, Jeffrey D.

    2017-03-01

    This study examines the predictability and dynamics of tropical cyclone (TC) secondary eyewall formation (SEF), eyewall replacement cycles (ERC), and intensity changes under moderate environmental shear through convection-permitting ensemble simulations. Even with the same environmental shear, the TC intensity changes during formation, rapid intensification, and SEF/ERC can be extremely sensitive to small, unobservable, random initial condition uncertainties, or computer's truncation error due to the chaotic nature of moist convection. Through composite analysis of five ensemble members with similar clear SEF/ERC and diagnostics with a nonlinear boundary layer (BL) model, we identify several key factors in the SEF/ERC process: (1) fast expansion of outer wind fields and changing inertial stability through shear-induced peripheral convection outside of the primary eyewall, (2) downward building and axisymmetrization of the primary (outer) rainband due to enhanced inertial stability and positive feedback between BL and outer convection, (3) establishment of the secondary eyewall along with moat formation that is facilitated by compensating subsidence from the primary eyewall, and (4) weakening and eventual replacement of the original primary eyewall by the strengthening secondary eyewall. It is also seen from the partial ERC cases that the preexisting rainband can be of great importance to the later development of SEF. Diagnosis with the nonlinear BL model shows that the location and relative strengths of the diagnosed frictional updrafts closely match those in the ensemble simulation of the ERC case, suggesting that the boundary layer convergence substantially influences the location of the convection in both eyewalls there.

  7. Seed Regeneration Potential of Canopy Gaps at Early Formation Stage in Temperate Secondary Forests, Northeast China

    PubMed Central

    Yan, Qiao-Ling; Zhu, Jiao-Jun; Yu, Li-Zhong

    2012-01-01

    Promoting the seed regeneration potential of secondary forests undergoing gap disturbances is an important approach for achieving forest restoration and sustainable management. Seedling recruitment from seed banks strongly determines the seed regeneration potential, but the process is poorly understood in the gaps of secondary forests. The objectives of the present study were to evaluate the effects of gap size, seed availability, and environmental conditions on the seed regeneration potential in temperate secondary forests. It was found that gap formation could favor the invasion of more varieties of species in seed banks, but it also could speed up the turnover rate of seed banks leading to lower seed densities. Seeds of the dominant species, Fraxinus rhynchophylla, were transient in soil and there was a minor and discontinuous contribution of the seed bank to its seedling emergence. For Quercus mongolica, emerging seedling number was positively correlated with seed density in gaps (R = 0.32, P<0.01), especially in medium and small gaps (<500 m2). Furthermore, under canopies, there was a positive correlation between seedling number and seed density of Acer mono (R = 0.43, P<0.01). Gap formation could promote seedling emergence of two gap-dependent species (i.e., Q. mongolica and A. mono), but the contribution of seed banks to seedlings was below 10% after gap creation. Soil moisture and temperature were the restrictive factors controlling the seedling emergence from seeds in gaps and under canopies, respectively. Thus, the regeneration potential from seed banks is limited after gap formation. PMID:22745771

  8. 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.

  9. 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

  10. Induction of secondary axis in hydra revisited: New insights into pattern formation

    PubMed Central

    Kadu, Vishal; S. Ghaskadbi, Saroj; Ghaskadbi, Surendra

    2012-01-01

    In 1909, several years before the famous `Organizer’ experiments of Spemann and Mangold, Ethel Browne demonstrated induction of a secondary axis in hydra by grafting a hypostome. Based on this and subsequent work, in the late sixties, Lewis Wolpert proposed the theory of morphogen gradients and positional information. We have studied secondary axis induction by hypostome and foot tissue using three species of hydra as well as transgenic, GFP-expressing lines of hydra. We have found that pieces of hypostome and complete foot of a donor hydra can induce a secondary axis all along (in upper, middle or lower parts of) the body column of a host hydra, both within and across species with comparable rates. Thus, contrary to the available literature, our results show that the host hypostome does not completely inhibit the induction of a secondary axis. The length of the induced axis though is determined by the position of the graft. By using GFP-expressing lines of hydra we have demonstrated that host ectodermal and endodermal cells actively contribute to the secondary axis. On comparison, the hypostome was found to be a stronger and dominant Organizer than the foot. Foot grafting experiments show a transient increase in the host length as well as the distance between the two Organizers. The length becomes normal once the grafted foot reaches the budding zone. Our work brings out several new aspects of the role of positional cues in pattern formation in hydra that can be now be explored at cellular and molecular levels. PMID:24551754

  11. 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.

  12. 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.

  13. [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.

  14. Gasoline emissions dominate over diesel in formation of secondary organic aerosol mass

    NASA Astrophysics Data System (ADS)

    Bahreini, R.; Middlebrook, A. M.; de Gouw, J. A.; Warneke, C.; Trainer, M.; Brock, C. A.; Stark, H.; Brown, S. S.; Dube, W. P.; Gilman, J. B.; Hall, K.; Holloway, J. S.; Kuster, W. C.; Perring, A. E.; Prevot, A. S. H.; Schwarz, J. P.; Spackman, J. R.; Szidat, S.; Wagner, N. L.; Weber, R. J.; Zotter, P.; Parrish, D. D.

    2012-03-01

    Although laboratory experiments have shown that organic compounds in both gasoline fuel and diesel engine exhaust can form secondary organic aerosol (SOA), the fractional contribution from gasoline and diesel exhaust emissions to ambient SOA in urban environments is poorly known. Here we use airborne and ground-based measurements of organic aerosol (OA) in the Los Angeles (LA) Basin, California made during May and June 2010 to assess the amount of SOA formed from diesel emissions. Diesel emissions in the LA Basin vary between weekdays and weekends, with 54% lower diesel emissions on weekends. Despite this difference in source contributions, in air masses with similar degrees of photochemical processing, formation of OA is the same on weekends and weekdays, within the measurement uncertainties. This result indicates that the contribution from diesel emissions to SOA formation is zero within our uncertainties. Therefore, substantial reductions of SOA mass on local to global scales will be achieved by reducing gasoline vehicle emissions.

  15. Popliteal pseudoaneurysm after arthroscopic posterior cruciate ligament reconstruction.

    PubMed

    van Dorp, Karin B; Breugem, Stefan J M; Driessen, Marcel J M

    2014-09-01

    This report presents the case of a 30-year-old motocross (BMX) cyclist with a third-degree posterior cruciate ligament rupture. The technique used for reconstruction was the transtibial single-bundle autologous hamstring technique. Unfortunately, the procedure was complicated by a popliteal pseudoaneurysm, which was located in line with the tibial canal. The pseudoaneurysm was treated with an end-to-end anastomosis and the patient recovered without further complaints. In this case, the popliteal artery was damaged most probably by the edge of the reamer or the guide wire during removal. Vascular complications can be limb- and life-threatening. This case report aims to increase the awareness of this serious complication with a review of the literature.

  16. Popliteal Pseudoaneurysm after Arthroscopic Posterior Cruciate Ligament Reconstruction

    PubMed Central

    Breugem, Stefan J.M.; Driessen, Marcel J.M.

    2014-01-01

    This report presents the case of a 30-year-old motocross (BMX) cyclist with a third-degree posterior cruciate ligament rupture. The technique used for reconstruction was the transtibial single-bundle autologous hamstring technique. Unfortunately, the procedure was complicated by a popliteal pseudoaneurysm, which was located in line with the tibial canal. The pseudoaneurysm was treated with an end-to-end anastomosis and the patient recovered without further complaints. In this case, the popliteal artery was damaged most probably by the edge of the reamer or the guide wire during removal. Vascular complications can be limb- and life-threatening. This case report aims to increase the awareness of this serious complication with a review of the literature. PMID:25229050

  17. 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

  18. Ortner's syndrome: Cardiovocal syndrome caused by aortic arch pseudoaneurysm.

    PubMed

    Al Kindi, Adil H; Al Kindi, Faiza A; Al Abri, Qasim S; Al Kemyani, Nasser A

    2016-10-01

    72-year-old hypertensive presented with two weeks history of left sided chest pain and hoarseness. Workup demonstrated a pseudoaneurysm in the lesser curvature of the distal aortic arch opposite the origin of the left subclavian artery from a penetrating atherosclerotic ulcer. Following a left carotid-subclavian bypass, endovascular stenting of the aorta was performed excluding the pseudoaneurysm. Patient had excellent angiographic results post-stenting. Follow up at 12 weeks demonstrated complete resolution of his symptoms and good stent position with no endo-leak. Ortner's syndrome describes vocal changes caused by cardiovascular pathology. It should be included in the differential diagnosis of patients with cardiovascular risk factors presenting with hoarseness. This case demonstrates the use of endovascular stents to treat the causative pathology with resolution of symptoms. In expert hands, it represents low risk, minimally invasive therapeutic strategy with excellent early results in patients who are high risk for open procedure.

  19. 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.

  20. Urban stress-induced biogenic VOC emissions impact secondary aerosol formation in Beijing

    NASA Astrophysics Data System (ADS)

    Ghirardo, A.; Xie, J.; Zheng, X.; Wang, Y.; Grote, R.; Block, K.; Wildt, J.; Mentel, T.; Kiendler-Scharr, A.; Hallquist, M.; Butterbach-Bahl, K.; Schnitzler, J.-P.

    2015-08-01

    Trees can significantly impact the urban air chemistry by the uptake and emission of reactive biogenic volatile organic compounds (BVOCs), which are involved in ozone and particle formation. Here we present the emission potentials of "constitutive" (cBVOCs) and "stress-induced" BVOCs (sBVOCs) from the dominant broadleaf woody plant species in the megacity of Beijing. Based on an inventory of BVOC emissions and the tree census, we assessed the potential impact of BVOCs on secondary particulate matter formation in 2005 and 2010, i.e., before and after realizing the large tree-planting program for the 2008 Olympic Games. We found that sBVOCs, such as fatty acid derivatives, benzenoids and sesquiterpenes, constituted a significant fraction (∼ 15 %) of the total annual BVOC emissions, and we estimated that the overall annual BVOC budget may have doubled from ∼ 3.6 × 109 g C year-1 in 2005 to ∼ 7.1 × 109 g C year-1 in 2010 due to the increase in urban greens, while at the same time, the emission of anthropogenic VOCs (AVOCs) could be lowered by 24 %. Based on our BVOC emission assessment, we estimated the biological impact on SOA mass formation in Beijing. Compared to AVOCs, the contribution of biogenic precursors (2-5 %) for secondary particulate matter in Beijing was low. However, sBVOCs can significantly contribute (∼ 40 %) to the formation of total secondary organic aerosol (SOA) from biogenic sources; apparently, their annual emission increased from 1.05 μg m-3 in 2005 to 2.05 μg m-3 in 2010. This study demonstrates that biogenic and, in particular, sBVOC emissions contribute to SOA formation in megacities. However, the main problems regarding air quality in Beijing still originate from anthropogenic activities. Nevertheless, the present survey suggests that in urban plantation programs, the selection of plant species with low cBVOC and sBVOC emission potentials have some possible beneficial effects on urban air quality.

  1. 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]).

  2. 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.

  3. Repair of a recurrent pseudoaneurysm of the ascending aorta in an atomic bomb survivor with myelodysplastic syndrome.

    PubMed

    Hattori, Reiji; Nakao, Yoshihisa; Okada, Takayuki; Johno, Hiroyuki; Enoki, Chiharu; Sumida, Tomohiko; Imamura, Hiroji

    2009-01-01

    The occurrence of infective aortic pseudoaneurysms tends to be intractable and difficult to treat. We experienced a very rare case of a recurrent infective pseudoaneurysm in the ascending aorta that occurred after cardiac surgery in an atomic bomb survivor with myelodysplastic syndrome. The pseudoaneurysm was successfully repaired using a femoral artery autograft with an omentopexy and the patient recovered well without any recurrence.

  4. Successful Embolization of an Ovarian Artery Pseudoaneurysm Complicating Obstetric Hysterectomy

    SciTech Connect

    Rathod, Krantikumar R Deshmukh, Hemant L; Asrani, Ashwin; Salvi, Vinita S; Prabhu, Santoshi

    2005-01-15

    Transcatheter arterial embolization is becoming the therapy of choice for controlling obstetric hemorrhage, affording the ability to control persistent bleeding from pelvic vessels while avoiding the morbidity of surgical exploration. The clinicians are left with little choice if pelvic hemorrhage continues after hysterectomy and ligation of anterior division of both internal iliac arteries. We present one such case of intractable post-obstetric hysterectomy hemorrhage in which an ovarian artery pseudoaneurysm was diagnosed angiographically and successfully embolized, highlighting the role of transcatheter embolization.

  5. 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.

  6. 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.

  7. Dealing with a left ventricular pseudoaneurysm during assist device implant.

    PubMed

    Ha, Richard V; Chiu, Peter; Banerjee, Dipanjan; Sheikh, Ahmad Y

    2016-06-01

    Despite increasing use of left ventricular devices for the surgical treatment of heart failure, there is limited experience with implantation of devices in the setting of challenging left apical anatomy. We report the case of a 68-year-old man with a chronic post-infarction calcified apical pseudoaneurysm, who underwent pseudoaneurysmectomy, ventricular myoplasty, and left ventricular assist device implantation. A review of the literature and operative strategies are presented. © The Author(s) 2015.

  8. Impairment of Cellulose Synthases Required for Arabidopsis Secondary Cell Wall Formation Enhances Disease Resistance[W

    PubMed Central

    Hernández-Blanco, Camilo; Feng, Dong Xin; Hu, Jian; Sánchez-Vallet, Andrea; Deslandes, Laurent; Llorente, Francisco; Berrocal-Lobo, Marta; Keller, Harald; Barlet, Xavier; Sánchez-Rodríguez, Clara; Anderson, Lisa K.; Somerville, Shauna; Marco, Yves; Molina, Antonio

    2007-01-01

    Cellulose is synthesized by cellulose synthases (CESAs) contained in plasma membrane–localized complexes. In Arabidopsis thaliana, three types of CESA subunits (CESA4/IRREGULAR XYLEM5 [IRX5], CESA7/IRX3, and CESA8/IRX1) are required for secondary cell wall formation. We report that mutations in these proteins conferred enhanced resistance to the soil-borne bacterium Ralstonia solanacearum and the necrotrophic fungus Plectosphaerella cucumerina. By contrast, susceptibility to these pathogens was not altered in cell wall mutants of primary wall CESA subunits (CESA1, CESA3/ISOXABEN RESISTANT1 [IXR1], and CESA6/IXR2) or POWDERY MILDEW–RESISTANT5 (PMR5) and PMR6 genes. Double mutants indicated that irx-mediated resistance was independent of salicylic acid, ethylene, and jasmonate signaling. Comparative transcriptomic analyses identified a set of common irx upregulated genes, including a number of abscisic acid (ABA)–responsive, defense-related genes encoding antibiotic peptides and enzymes involved in the synthesis and activation of antimicrobial secondary metabolites. These data as well as the increased susceptibility of ABA mutants (abi1-1, abi2-1, and aba1-6) to R. solanacearum support a direct role of ABA in resistance to this pathogen. Our results also indicate that alteration of secondary cell wall integrity by inhibiting cellulose synthesis leads to specific activation of novel defense pathways that contribute to the generation of an antimicrobial-enriched environment hostile to pathogens. PMID:17351116

  9. Secondary structure formations of conotoxin genes: a possible role in mediating variability.

    PubMed

    Dewan, Kalyan Kumar

    2006-10-20

    Small venomous peptides called conotoxins produced by the predatory marine snail (genus Conus) present an interesting case for mutational studies. They have a high degree of amino acid variability among them yet they possess highly conserved structural elements that are defined by cysteine residues forming disulfide bridges along the length of the mature peptide. It has been observed that codons specifying these cysteines are also highly conserved. It is unknown how such codon conservation is maintained within the mature conotoxin gene since this entire region undergoes an accelerated rate of mutation. There is evidence suggesting that nucleic acids wield some influence in mechanisms that dictate the region and frequency where mutations occur in DNA. Nucleic acids exert this effect primarily through secondary structures that bring about local peaks and troughs in the energy relief of these transient formations. Secondary structure predictions of several conotoxin genes were analyzed to see if there was any correspondence between the highly variable regions of the conotoxin. Regions of the DNA encompassing the conserved Cys codons (and several other conserved amino acid codons) have been found to correspond to predicted secondary structures of higher stabilities. In stark contrast the regions of the conotoxin that have a higher degree of variation correlate to regions of lower stability. This striking co-relation allows for a simple model of inaccessibility of a mutator to these highly conserved regions of the conotoxin gene allowing them a relative degree of resistance towards change.

  10. 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.

  11. 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.

  12. 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.

  13. Aqueous-phase secondary organic aerosol and organosulfate formation in atmospheric aerosols: a modeling study.

    PubMed

    McNeill, V Faye; Woo, Joseph L; Kim, Derek D; Schwier, Allison N; Wannell, Neal J; Sumner, Andrew J; Barakat, Joseph M

    2012-08-07

    We have examined aqueous-phase secondary organic aerosol (SOA) and organosulfate (OS) formation in atmospheric aerosols using a photochemical box model with coupled gas-phase chemistry and detailed aqueous aerosol chemistry. SOA formation in deliquesced ammonium sulfate aerosol is highest under low-NO(x) conditions, with acidic aerosol (pH = 1) and low ambient relative humidity (40%). Under these conditions, with an initial sulfate loading of 4.0 μg m(-3), 0.9 μg m(-3) SOA is predicted after 12 h. Low-NO(x) aqueous-aerosol SOA (aaSOA) and OS formation is dominated by isoprene-derived epoxydiol (IEPOX) pathways; 69% or more of aaSOA is composed of IEPOX, 2-methyltetrol, and 2-methyltetrol sulfate ester. 2-Methyltetrol sulfate ester comprises >99% of OS mass (66 ng m(-3) at 40% RH and pH 1). In urban (high-NO(x)) environments, aaSOA is primarily formed via reversible glyoxal uptake, with 0.12 μg m(-3) formed after 12 h at 80% RH, with 20 μg m(-3) initial sulfate. OS formation under all conditions studied is maximum at low pH and lower relative humidities (<60% RH), i.e., when the aerosol is more concentrated. Therefore, OS species are expected to be good tracer compounds for aqueous aerosol-phase chemistry (vs cloudwater processing).

  14. Modeling Photosensitized Secondary Organic Aerosol Formation in Laboratory and Ambient Aerosols.

    PubMed

    Tsui, William G; Rao, Yi; Dai, Hai-Lung; McNeill, V Faye

    2017-07-05

    Photosensitized reactions involving imidazole-2-carboxaldehyde (IC) have been experimentally observed to contribute to secondary organic aerosol (SOA) growth. However, the extent of photosensitized reactions in ambient aerosols remains poorly understood and unaccounted for in atmospheric models. Here we use GAMMA 4.0, a photochemical box model that couples gas-phase and aqueous-phase aerosol chemistry, along with recent laboratory measurements of the kinetics of IC photochemistry, to analyze IC-photosensitized SOA formation in laboratory and ambient settings. Analysis of the laboratory results of Aregahegn et al. (2013) suggests that photosensitized production of SOA from limonene, isoprene, α-pinene, β-pinene, and toluene by (3)IC* occurs at or near the surface of the aerosol particle. Reactive uptake coefficients were derived from the experimental data using GAMMA 4.0. Simulations of aqueous aerosol SOA formation at remote ambient conditions including IC photosensitizer chemistry indicate less than 0.3% contribution to SOA growth from direct reactions of (3)IC* with limonene, isoprene, α-pinene, β-pinene, and toluene, and an enhancement of less than 0.04% of SOA formation from other precursors due to the formation of radicals in the bulk aerosol aqueous phase. Other, more abundant photosensitizer species, such as humic-like substances (HULIS), may contribute more significantly to aqueous aerosol SOA production.

  15. 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.

  16. Heterogeneous Chemistry of Carbonyls and Alcohols With Sulfuric Acid: Implications for Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Levitt, N.; Zhang, R.

    2006-12-01

    Recent environmental chamber studies have suggested that acid-catalyzed particle-phase reactions of organic carbonyls lead to multifold increases in secondary organic aerosol (SOA) mass and acid-catalyzed reactions between alcohols and aldehydes in the condensed phase lead to the formation of hemiacetals and acetals, also enhancing secondary organic aerosol growth. The kinetics and mechanism of the heterogeneous chemistry of carbonyls and alcohols with sulfuric acid, however, remain largely uncertain. In this talk, we present measurements of heterogeneous uptake of several carbonyls and alcohols on liquid H2SO4 in a wide range of acid concentrations and temperatures. The results indicate that uptake of larger carbonyls is explained by aldol condensation. For small dicarbonyls, heterogeneous reactions are shown to decrease with acidity and involve negligible formation of sulfate esters. Hydration and polymerization likely explain the measured uptake of such small dicarbonyls on H2SO4 and the measurements do not support an acid- catalyzed uptake. Atmospheric implications from our findings will be discussed.

  17. Effect of Biodentine on secondary caries formation: An in vitro study.

    PubMed

    Özgül, Betül Memis; Tirali, R Ebru; Cehreli, S Burcak

    2016-04-01

    To compare the effects of two materials, Biodentine and conventional glass-ionomer cement (CGIC), on secondary caries formation around restorations when used as a dentin replacement material. 30 approximal cavities were prepared on mesial and distal surfaces of 15 caries-free human premolar teeth extracted for orthodontic or periodontal reasons. Cavities were filled with A: Biodentine as a base + Filtek Z250 composite (n = 15) or B: CGIC as a base + Filtek Z250 composite (n = 15). The materials were applied according to the manufacturers' instructions. Teeth were thermocycled, and placed in a demineralizing solution for 5 weeks. Secondary caries formation was assessed using the International Caries Detection and Assessment System (ICDAS) II and quantitative computer- aided image measurement of caries depth. The computer-aided measurements showed that the Biodentine group had significantly lower lesion depth measurements than the CGIC group (P = 0.004). However, there was no significant difference among the groups based on the ICDAS II scores (P > 0.05).

  18. 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.

  19. 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

  20. Ozone and secondary organic aerosol formation potential from anthropogenic volatile organic compounds emissions in China.

    PubMed

    Wu, Wenjing; Zhao, Bin; Wang, Shuxiao; Hao, Jiming

    2017-03-01

    Volatile organic compounds (VOCs) are major precursors for ozone and secondary organic aerosol (SOA), both of which greatly harm human health and significantly affect the Earth's climate. We simultaneously estimated ozone and SOA formation from anthropogenic VOCs emissions in China by employing photochemical ozone creation potential (POCP) values and SOA yields. We gave special attention to large molecular species and adopted the SOA yield curves from latest smog chamber experiments. The estimation shows that alkylbenzenes are greatest contributors to both ozone and SOA formation (36.0% and 51.6%, respectively), while toluene and xylenes are largest contributing individual VOCs. Industry solvent use, industry process and domestic combustion are three sectors with the largest contributions to both ozone (24.7%, 23.0% and 17.8%, respectively) and SOA (22.9%, 34.6% and 19.6%, respectively) formation. In terms of the formation potential per unit VOCs emission, ozone is sensitive to open biomass burning, transportation, and domestic solvent use, and SOA is sensitive to industry process, domestic solvent use, and domestic combustion. Biomass stoves, paint application in industrial protection and buildings, adhesives application are key individual sources to ozone and SOA formation, whether measured by total contribution or contribution per unit VOCs emission. The results imply that current VOCs control policies should be extended to cover most important industrial sources, and the control measures for biomass stoves should be tightened. Finally, discrepant VOCs control policies should be implemented in different regions based on their ozone/aerosol concentration levels and dominant emission sources for ozone and SOA formation potential. Copyright © 2016. Published by Elsevier B.V.

  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. Atmospheric chemistry of nitrogenous aerosols in Northeast Asia: biological sources and secondary formation

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Fu, P. Q.

    2015-04-01

    To better understand the sources of nitrogenous aerosols, particularly water-soluble organic nitrogen (WSON) and water-insoluble organic nitrogen (WION), in Northeast Asia, we measured total nitrogen (TN) and water-soluble total nitrogen (WSTN) as well as nitrogen isotope ratios (δ15N) of TN (δ15NTN) and WSTN (δ15NWSTN) in the total suspended particles (TSP) collected from Sapporo, northern Japan for one-year period. In general, WION was more abundant (126 ± 117 ng m-3) whereas WSON (89.7 ± 80.6 ng m-3), accounting for 14 ± 11% and 9.2 ± 7.3% of TN, respectively. WSON peaked in late autumn to winter (maximum 288 ng m-3) and WION peaked in mid spring to early summer (454 ng m-3). δ15NTN (21.9 ± 4.1‰) and δ15NWSTN (25.8 ± 8.2‰) showed peaks in summer with relatively high ratios in late autumn. Based on the seasonal variations of WSON and WION together with organic tracers, fossil fuel combustion and biomass burning are found to be two major sources of WSON whereas emissions of biological particles and secondary formation by reactions of biogenic secondary organic species (carbonyls) with NH3 are suggested as important source of WION. The seasonality of δ15NTN and δ15NWSTN, together with the comparisons to literature values, implies that chemical aging (including gas/particle partitioning) and biomass burning are the causes of the enhanced values in summer and autumn, respectively. This study demonstrates that contributions of aerosol N from fossil fuel combustion and biomass burning dominate in autumn/winter whereas emission of terrestrial biological particles and secondary formation from biogenic hydrocarbons and subsequent chemical aging in the atmosphere are important in spring/summer in Northeast Asia.

  4. Atmospheric chemistry of nitrogenous aerosols in northeastern Asia: biological sources and secondary formation

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Fu, P. Q.

    2015-09-01

    To better understand the sources of nitrogenous aerosols, particularly water-soluble organic nitrogen (WSON) and water-insoluble organic nitrogen (WION), in northeastern Asia, we measured total nitrogen (TN) and water-soluble total nitrogen (WSTN) as well as nitrogen isotope ratios (δ15N) of TN (δ15NTN) and WSTN (δ15NWSTN) in the total suspended particulate (TSP) samples collected from Sapporo, northern Japan, for a 1-year period. In general, WION was more abundant (126 ± 117 ng m-3), whereas WSON was 89.7 ± 80.6 ng m-3, accounting for 14 ± 11 % and 9.2 ± 7.3 % of TN, respectively. WSON peaked in late autumn to winter (maximum 288 ng m-3) and WION peaked in mid-spring to early summer (454 ng m-3). δ15NTN (21.9 ± 4.1 ‰) and δ15NWSTN (25.8 ± 8.2 ‰) showed peaks in summer with relatively high ratios in late autumn. Based on the seasonal variations in WSON and WION together with organic tracers, fossil fuel combustion and biomass burning are found to be two major sources of WSON, whereas emissions of biological particles and secondary formation by reactions of biogenic secondary organic species (carbonyls) with NH3 are suggested as an important source of WION. The seasonality of δ15NTN and δ15NWSTN, together with the comparisons to literature values, implies that chemical aging (including gas-particle partitioning) and biomass burning are the causes of the enhanced values in summer and autumn, respectively. This study demonstrates that contributions of aerosol N from fossil fuel combustion and biomass burning dominate in autumn and/or winter, whereas emission of terrestrial biological particles and secondary formation from biogenic hydrocarbons and subsequent chemical aging in the atmosphere are important in spring and/or summer in northeastern Asia.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, B. B.; Campuzano-Jost, P.; Ortega, A. M.; Day, D. A.; Kaser, L.; Jud, W.; Karl, T.; Hansel, A.; Hunter, J. F.; Cross, E. S.; Kroll, J. H.; Peng, Z.; Brune, W. H.; Jimenez, J. L.

    2015-11-01

    Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR) located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA) formation and aging. High OH concentrations and short residence times allowed for semi-continuous 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 time scales 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 4 μg m-3 when LVOC fate corrected) compared to daytime (average 1 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 LT. 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), 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 compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH oxidation than

  11. 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.

  12. Delayed carotid pseudoaneurysm: a life-threatening complication after endoscopic sinus surgery.

    PubMed

    Golinelli, Gloria; Toso, Andrea; Taranto, Fausto; Aluffi, Paolo; Pia, Francesco

    2012-11-01

    Internal carotid artery pseudoaneurysm is a rare but potentially lethal complication of sinus surgery. We present 2 cases of delayed carotid pseudoaneurysm development after internal carotid laceration during functional sinus surgery for chronic sinusitis to emphasize the need to follow up the patients with profuse bleeding perioperatively and to identify when to suspect iatrogenic vascular malformations.

  13. 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.

  14. Pseudoaneurysm with Arteriovenous Fistula after Arthroscopic Procedure: A Rare Complication of Arthroscopy.

    PubMed

    Jin, Moran; Lee, Yang-Haeng; Yoon, Young Chul; Han, Il-Yong; Park, Kyung-Taek; Wi, Jin Hong

    2015-08-01

    Pseudoaneurysm with arteriovenous fistula is a rare complication of arthroscopy, and can be diagnosed by ultrasonography, computed tomography, magnetic resonance imaging, or angiography. This condition can be treated with open surgical repair or endovascular repair. We report our experience with the open surgical repair of a pseudoaneurysm with an arteriovenous fistula in a young male patient who underwent arthroscopy five months previously.

  15. Successful repair of ascending aortic pseudoaneurysm using autograft patch from fascia lata and saphenous vein.

    PubMed

    Yamashita, Katsushi; Kazui, Teruhisa; Suzuki, Kazuya; Terada, Hitoshi; Washiyama, Naoki; Hasan, Abul; Bashar, Muhammad

    2007-12-01

    An 80-year-old man developed a pseudoaneurysm in the ascending aorta due to mediastinitis following cardiac surgery. We successfully repaired the pseudoaneurysm with an autograft patch harvested from fascia lata and the saphenous vein. The repair, which was carried out in two layers, can be expected to be durable.

  16. Endovascular Treatment of a Vertebral Artery Pseudoaneurysm in a Drug User

    SciTech Connect

    Mourikis, Dimitrios; Chatziioannou, Achilleas; Doriforou, Ortansia; Skiadas, Vasilios Koutoulidis, Vasilios; Katsenis, Konstantinos; Vlahos, Lampros

    2006-08-15

    A 26-year-old drug abuser who presented with sepsis was found to have a pseudoaneurysm in the left vertebral artery. This aneurysm was presumed to be post-traumatic, since the patient reported multiple attempts to inject drugs in the left jugular vein 15 days prior to admission. The pseudoaneurysm was treated effectively with stent-graft placement.

  17. 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.

  18. 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

  19. Pseudoaneurysm of the hepatic artery, a rare complication of an amebic liver abscess

    PubMed Central

    Tacconi, D.; Lapini, L.; Giorni, P.; Corradini, S.; Caremani, M.

    2009-01-01

    Hepatic artery pseudoaneurysm is a rare complication of amebic or pyogenic liver abscesses, and it is generally diagnosed because of hemobilia due to rupture of the aneurysm into the biliary tract. The authors describe a case of vascular complication in a patient affected by amebic liver abscess. Pseudoaneurysm was diagnosed and resolved without hemobilia. PMID:23396987

  20. Amoebic liver abscess with hepatic artery pseudoaneurysm: successful treatment by interventional radiology.

    PubMed

    Yadav, Ajit K; Gupta, Saumya; Hariprasad, Sudarsan; Kumar, Ashish; Ghuman, Samarjit S; Gupta, Arun

    2015-03-01

    Amoebic liver abscess is most common extra-intestinal presentation of amoebiasis. It is rarely complicated with vascular involvement including thrombosis of hepatic vein or IVC and pseudo-aneurysm of hepatic artery. We describe a case of hepatic artery pseudo-aneurysm as a complication of amoebic liver abscess treated with percutaneous embolization.

  1. 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.

  2. 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.

  3. Secondary Organic Aerosol Formation of Tailpipe Emissions from On-road Gasoline Vehicles

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Lambe, A. T.; Saleh, R.; Saliba, G.; Drozd, G.; Maldonado, H.; Sardar, S.; Frodin, B.; Russell, L. M.; Goldstein, A. H.; Robinson, A. L.

    2016-12-01

    On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We tested a fleet of on-road gasoline vehicles using a cold-start unified cycle on the dynamometer to investigate SOA formation from the OH radical oxidation of gasoline vehicle tailpipe emissions using a smog chamber and a Potential Aerosol Mass (PAM) oxidation flow reactor. These vehicles were recruited from California in-use on-road vehicles and covered a wide range of emission standards, including Super Ultra-Low Emission vehicles (SULEVs) that meet the most stringent emission standard. The PAM reactor complements the smog chamber by enabling us to characterize SOA production from the oxidation of gasoline vehicular exhaust over longer OH exposure times. Comprehensive chemical analysis of non-methane hydrocarbons (NMHCs) in tailpipe emissions from gasoline vehicles has been carried out to determine SOA precursors, including intermediate volatility and semi-volatile organic compounds. We observed less SOA production from newer, lower NMHC emitting vehicles compared to older, higher-emitting vehicles. No SOA production was observed for SULEV vehicles during smog chamber experiments, but SOA production for SULEV vehicles was about a factor of 4 greater than primary organic aerosol in the PAM reactor. In addition, we have investigated the SOA formation potential and the composition of SOA under a range of conditions, including organic aerosol concentrations, SOA precursor concentrations and OH exposure, by comparing the SOA formation in the smog chamber to the PAM reactor. Our measurements of SOA formation and characterization of NMHCs identify the major classes of SOA precursors and determine the effectiveness of the tightening of emission standards to reduce SOA. Our results will significantly improve our understanding of SOA formation in the atmosphere.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Secondary aerosol formation from the oxidation of biogenic hydrocarbons by chlorine atoms

    NASA Astrophysics Data System (ADS)

    Cai, Xuyi; Griffin, Robert J.

    2006-07-01

    The chlorine atom (Cl) is a potential oxidant of volatile organic compounds (VOCs) in the atmosphere and is hypothesized to lead to secondary organic aerosol (SOA) formation in coastal and industrialized areas. The purpose of this paper is to test this hypothesis and to quantify the SOA formation potentials of the common monoterpenes α-pinene, β-pinene, and d-limonene when oxidized by Cl in laboratory chamber experiments. Results indicate that the oxidation of these monoterpenes generates significant amounts of aerosol. The SOA yields of α-pinene, β-pinene, and d-limonene in this study are comparable to those when they are oxidized by ozone, by nitrate radical, and in photooxidation scenarios. For aerosol mass up to 30.0 μg m-3, their yields reach approximately 0.20, 0.20, and 0.30, respectively. For d-limonene, data indicate two yield curves that depend on the initial concentration ratio of Cl precursor to d-limonene. It is argued theoretically that multiple SOA yield curves may be common for VOCs, depending on the initial concentration ratio of oxidant to VOC. SOA formation from the three typical monoterpenes when oxidized by Cl in the marine boundary layer, coastal areas, and inland industrialized areas could be a source of organic aerosol in the early morning.

  13. 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

  14. Interactions between SO2 oxidation and Secondary Organic Aerosol formation through Criegee intermediate chemistry

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Ye, J.; Abbatt, J.

    2016-12-01

    Ozonolysis of monoterpenes is an important source of atmospheric biogenic secondary organic aerosol (BSOA). While enhanced BSOA formation has been repeatedly observed under sulfate-rich conditions in both field studies and laboratory experiments, the underlying mechanisms remain poorly understood. In this work, the effect of SO2 on BSOA formation from monoterpene ozonolysis was investigated. The role of stabilized Criegee biradicals (sCIs) generated from alkene ozonolysis on SO2 oxidation was examined under different humidity conditions (<5% vs. 50%). Experiments were conducted in a 1 m3 Teflon chamber. BSOA was produced from ozonolysis of a-pinene or limonene. SO2 concentration was injected at various levels ranging from 30 to 100 ppb. In all experiments, cyclohexane was used as OH scavenger and added at sufficient amount to minimize the influence from OH + monoterpenes reaction. SOA samples were collected for composition analysis. Preliminary results show that BSOA from monoterpene ozonolysis is significantly enhanced in the presence of SO2 under dry conditions. SOA enhancement increases with increasing the concentration of SO2. However, the enhancement became negligible as the conditions became more humid. Control experiments show that SO2 is consumed at timescales consistent with oxidation by sCIs indicating that gaseous SO2 interacts directly with reactive intermediates during monoterpene ozonolysis. Organosulfate formation is probed by electrospray ionization-ion mobility time of flight mass spectrometer (ESI-IMS/TOF). The effect of SO2 on ozonolysis mechanism and chemical composition will be discussed.

  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. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. Ozonolysis of a series of biogenic organic volatile compounds and secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Bernard, François; Quilgars, Alain; Cazaunau, Mathieu; Grosselin, Benoît.; Daele, Véronique; Mellouki, Abdelwahid; Winterhalter, Richard; Moortgat, Geert K.

    2010-05-01

    Secondary organic aerosols are formed via nucleation of atmospheric organic vapours on pre-existing particles observed in various rural environments where the organic fraction represents the major part of the observed nano-particle (Kavouras and Stephanou, 2002; Kulmala et al., 2004a). However, nucleation of organic vapors appears to be unlikely thermodynamically in relevant atmospheric conditions (Kulmala et al., 2004b). In this work, a systematic study has been conducted to investigate the aerosol formation through the ozonolysis of a series of monotepenes using a newly developed aerosol flow reactor and the ICARE indoor simulation chamber. The nucleation thresholds have been determined for SOA formed through the reaction of ozone with a-Pinene, sabinene, myrcene and limonene in absence of any observable existing particles. The measurements were performed using the flow reactor combined to a particle counter (CPC 3022). Number concentrations of SOA have been measured for different concentration of consumed monoterpenes. The data obtained allow us to estimate the nucleation threshold for a range of 0.2 - 45 ppb of consumed monoterpenes. The nucleation threshold values obtained here (≤ 1 ppb of the consumed monoterpenes) have been found to be lower than the previously reported ones (Berndt et al., 2003; Bonn and Moortgat, 2003; Koch et al., 2000; Lee and Kamens, 2005). The ICARE simulation chamber has been used to study the mechanism of the reaction of ozone with various acyclic terpenes (myrcene, ocimene, linalool and a-farnesene) and to derive the SOA mass formation yield. The time-concentration profiles of reactants and products in gas-phase were obtained using in-situ Fourier Transform Infrared Spectroscopy. In addition, the number and mass concentrations of SOA have been monitored with a Scanning Mobility Particle Sizer. The chemical composition of the SOA formed has been tentatively characterised using Liquid Chromatography - Mass Spectrometry. The results

  6. 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

  7. 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

  8. Secondary formation products in power plant plumes. Final report August 1979-December 1980

    SciTech Connect

    Balfour, W.D.; Edwards, L.O.; Tannahill, G.K.

    1981-05-01

    Source and airborne measurements were made in October 1979, at the TVA Widows Creek Steam Plant in northeastern Alabama. Primary emissions from the flue gas stacks were determined including total mass, particle size distribution, SO2, NOx, and SO3/H2SO4. An instrumented fixed wing airplane was used to acquire plume data at various altitudes and downwind distances. This data was used to establish secondary pollutant formation rates. Sulfate transformation rates were measured between 4.3 percent/hr and 0.6 percent/hr for a well-defined plume at 1.1 hr and 2.2 hr plume ages respectively. A chemical element balance around the scrubber indicates that as much as 40% of the total mass exiting the scrubber was generated from entrained liquor. This accounts for 90% of the unit's sulfate emissions. These primary emissions account for between 4 and 17% of the total sulfates measured downwind in the plume.

  9. 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.

  10. UV light selectively coinduces supply pathways from primary metabolism and flavonoid secondary product formation in parsley

    PubMed Central

    Logemann, Elke; Tavernaro, Annette; Schulz, Wolfgang; Somssich, Imre E.; Hahlbrock, Klaus

    2000-01-01

    The UV light-induced synthesis of UV-protective flavonoids diverts substantial amounts of substrates from primary metabolism into secondary product formation and thus causes major perturbations of the cellular homeostasis. Results from this study show that the mRNAs encoding representative enzymes from various supply pathways are coinduced in UV-irradiated parsley cells (Petroselinum crispum) with two mRNAs of flavonoid glycoside biosynthesis, encoding phenylalanine ammonia-lyase and chalcone synthase. Strong induction was observed for mRNAs encoding glucose 6-phosphate dehydrogenase (carbohydrate metabolism, providing substrates for the shikimate pathway), 3-deoxyarabinoheptulosonate 7-phosphate synthase (shikimate pathway, yielding phenylalanine), and acyl-CoA oxidase (fatty acid degradation, yielding acetyl-CoA), and moderate induction for an mRNA encoding S-adenosyl-homocysteine hydrolase (activated methyl cycle, yielding S-adenosyl-methionine for B-ring methylation). Ten arbitrarily selected mRNAs representing various unrelated metabolic activities remained unaffected. Comparative analysis of acyl-CoA oxidase and chalcone synthase with respect to mRNA expression modes and gene promoter structure and function revealed close similarities. These results indicate a fine-tuned regulatory network integrating those functionally related pathways of primary and secondary metabolism that are specifically required for protective adaptation to UV irradiation. Although the response of parsley cells to UV light is considerably broader than previously assumed, it contrasts greatly with the extensive metabolic reprogramming observed previously in elicitor-treated or fungus-infected cells. PMID:10677554

  11. 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

  12. 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. © 2013 Scandinavian Plant Physiology Society.

  13. 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.

  14. 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.

  15. Formation of Secondary Lherzolite and Refertilization of the Subcontinental Lithospheric Mantle: The Record of Orogenic Peridotites

    NASA Astrophysics Data System (ADS)

    Garrido, Carlos J.; Varas-Reus, María Isabel; Bodinier, Jean-Louis; Marchesi, Claudio; Bosch, Delphine; Hidas, Károly

    2016-04-01

    Correlations observed between major and minor transition elements in tectonically-emplaced orogenic peridotites have classically been ascribed to variable degrees of melt extraction. There is a growing body of evidence indicating that these chemical variations mostly reflect melt redistribution and near solidus reactions superimposed onto previous melting depletion events. Here we will assess this hypothesis using a large database of peridotites from orogenic peridotites in the westernmost Mediterranean (Ronda and Beni Bousera peridotites). We show that lherzolite samples show some trends in major elements and modal variations that are inconsistent with their interpretation as depleted MORB mantle (DMM). These trends are more consistent with the secondary formation of lherzolites by refertilization processes involving a least two different near-solidus, melt-processes: refertilization by pyroxenite-derived melts and by hydrous melts leading, respectively, to secondary lherzolites with Ol/Opx and Cpx/Opx ratios greater than those expected from residues from a primitive upper mantle source. Together with their N-MORB, LREE-depleted pattern, their fertile lherzolitic composition may have been acquired as a result of melt-rock interaction processes associated with the thermomechanical erosion of lithospheric mantle by asthenosphere. Major refertilization of depleted subcontinental mantle is an alternative to the small degrees of melt extraction to account for LREE depletion in otherwise fertile orogenic lherzolites.

  16. 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.

  17. 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.

  18. Oligomerization as a potential mechanism for Secondary Organic Aerosol (SOA) formation in clouds

    NASA Astrophysics Data System (ADS)

    Yasmeen, F.; Sauret, N.; Claeys, M.; Maria, P. C.; Massi, L.

    2009-04-01

    Electrospray ionization - mass spectrometry (ESI-MS) has been used to investigate oligomer formation in dark chamber experiments designed to study the polymerization conditions of common atmospheric photooxidation products without photochemical action. Methylglyoxal has been selected as the monomer considering, it is a gas-phase product from the atmospheric oxidation of isoprene and terpenes (biogenic sources) as well as of aromatic compounds (anthropogenic sources). Aqueous-phase oligomer formation of methylglyoxal has been investigated in a simulated cloud matrix, under dark conditions in view of its short life time (~1.6 hrs). A mechanistic pathway for the growth of oligomers via aldol condensation under cloud conditions and in the absence of UV-light and the OH radical is proposed here for the first time. Soluble oligomers (n=1-12) formed in the course of acid-catalyzed aldol condensation have been detected and identified by positive and negative ion ESI-MS, while their relative abundance is estimated from the full-scan mass spectra. In particular, oligomer abundances and their adduct formation was considered with special emphasis on the structural elucidation of these oligomers and their corresponding adduct products. The oligomer series starts with a β-hydroxy ketone via aldol condensation and oligomers are formed by multiple addition of C3H4O2 units (72 Da) to the parent β-hydroxy ketone. MS2 ion trap experiments have been performed to structurally characterize the oligomers. Oligomers could form under conditions encountered in clouds even at micromolar concentrations and thus could significantly result in secondary organic aerosol (SOA) after cloud droplet evaporation. Therefore, it is proposed that oligomer formation does not only occur during droplet evaporation when the concentrations of products increase but could as well be an in-cloud process and substantially enhance in-cloud SOA yields.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. Gas-phase products and secondary organic aerosol formation from the ozonolysis and photooxidation of myrcene

    NASA Astrophysics Data System (ADS)

    Böge, Olaf; Mutzel, Anke; Iinuma, Yoshiteru; Yli-Pirilä, Pasi; Kahnt, Ariane; Joutsensaari, Jorma; Herrmann, Hartmut

    2013-04-01

    Terrestrial vegetation releases a great variety of volatile organic compounds (VOC) into the atmosphere. Monoterpenes, like myrcene, contribute significantly to this global biogenic VOC emission. In the atmosphere, monoterpenes rapidly undergo oxidation reactions by OH radicals (mainly during the daytime), NO3 radicals (mainly during the nighttime) and O3 to form multifunctional oxidation products. The products of these reactions are likely to be of low volatility and hence might lead to secondary organic aerosol (SOA) formation. In the present study, we report results from a series of chamber experiments performed in the LEAK chamber at TROPOS in which the gas-phase products and SOA yields obtained from myrcene O3 reactions with and without an OH radical scavenger as well as from the myrcene OH radical reaction in the presence of NOx have been measured. During the experiments the consumption of myrcene as well as the formation of gas-phase products was monitored using a proton transfer reaction mass spectrometer (PTR-MS). Ozone concentration was measured by an O3 monitor and the mixing ratios of nitrogen oxides were measured by a NOx monitor. Particle size distributions between 3-900 nm were monitored every 11 min using a differential mobility particle sizer (DMPS) system. In addition to the products observed by means of the PTR-MS by their m/z values, an identification of carbonylic compounds by their DNPH derivatives was performed. Beside low molecular mass products the formation of 4-vinyl-4-pentenal with a yield of 55 % in myrcene ozonolysis has been observed. The further oxidation of this major first generation product lead to the formation of two dicarbonylic products with m/z 113 and to SOA formation. The influence of the continuing oxidation of 4-vinyl-4-pentenal on SOA formation will be discussed in detail. The emergence of the gas-phase product hydroxyacetone as direct result of the myrcene ozone reaction will be mooted, because hydroxyacetone seems to

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

    DOE PAGES

    Liu, Jiumeng; D’Ambro, Emma L.; Lee, Ben H.; ...

    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 subjects 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.more » SOA yield is initially constant with the addition of increasing amounts of nitric oxide (NO) but then sharply decreases for input concentrations above 50 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 preindustrial atmosphere and in biogenic-rich regions with limited anthropogenic impacts and suggest that a more-complex representation of NOx-dependent SOA yields may be important in models« less

  6. Secondary organic aerosol formation in cloud and fog droplets: a literature evaluation of plausibility

    NASA Astrophysics Data System (ADS)

    Blando, James D.; Turpin, Barbara J.

    This paper investigates the hypothesis that cloud and fog processes produce fine organic particulate matter in the atmosphere. The evidence provided suggests that cloud and fog processes could be important contributors to secondary organic aerosol formation, and the contribution of this formation pathway should be further investigated. This conclusion is based on the following observations: (1) many organic vapors present in the atmosphere are sorbed by suspended droplets and have been measured in cloud and fog water, (2) organics participate in aqueous-phase reactions, and (3) organic particulate matter is sometimes found in the size mode attributed to cloud processing (i.e. the droplet mode). Specific compounds identified as potential precursors include aldehydes (e.g. formaldehyde, acetaldehyde, and propionaldehyde), acetone, alcohols (e.g. methanol, ethanol, 2-propanol, and phenol), monocarboxylic acids, and organic peroxides. Carboxylic acids (e.g. diacids and oxo-acids), glyoxal, esters, organosulfur compounds, polyols, amines and amino acids are potential products of cloud and fog processing.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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 subjects 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 50 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 preindustrial atmosphere and in biogenic-rich regions with limited anthropogenic impacts and suggest that a more-complex representation of NOx-dependent SOA yields may be important in models

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. Secondary organic aerosol formation of relevance to the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Cai, Xuyi

    The chlorine atom (Cl) is a potential oxidant of volatile organic compounds (VOCs) in the atmosphere and is hypothesized to lead to secondary organic aerosol (SOA) formation in coastal areas. The purpose of this dissertation is to test this hypothesis and quantify the SOA formation potentials of some representative biogenic and anthropogenic hydrocarbons when oxidized by Cl in laboratory chamber experiments. The chosen model compounds for biogenic and anthropogenic hydrocarbons in this study are three monoterpenes (alpha-pinene, beta-pinene, and d-limonene) and two aromatics (m-xylene and toluene), respectively. Results indicate that the oxidation of these monoterpenes and aromatics generates significant amounts of aerosol. The SOA yields of alpha-pinene, beta-pinene, and d-limonene obtained in this study are comparable to those when they are oxidized by ozone, by nitrate radical, and in photooxidation scenarios. For aerosol mass up to 30.0 mug m-3, their yields reach approximately 0.20, 0.20, and 0.30, respectively. The SOA yields for m-xylene and toluene are found to be in the range of 0.035 to 0.12 for aerosol concentrations up to 19 mug m-3. For d-limonene and toluene, data indicate two yield curves that depend on the initial concentration ratios of Cl precursor to hydrocarbon hydrocarbon. Zero-dimensional calculations based on these yields show that SOA formation from the five model compounds when oxidized by Cl in the marine boundary layer could be a significant source of SOA in the early morning. In addition, the mechanistic reaction pathways for Cl oxidation of alpha-pinene, beta-pinene, d-limonene, and toluene with Cl have been developed within the framework of the Caltech Atmospheric Chemistry Mechanisms (CACM). Output from the developed mechanisms is combined with an absorptive partitioning model to predict precursor decay curves and time-dependent SOA concentrations in experiments. Model calculations are able to match (in general within general +/- 50

  17. 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.

  18. Aqueous photooxidation of ambient Po Valley Italy air samples: Insights into secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Kirkland, J. R.; Lim, Y. B.; Sullivan, A. P.; Decesari, S.; Facchini, C.; Collett, J. L.; Keutsch, F. N.; Turpin, B. J.

    2012-12-01

    In this work, we conducted aqueous photooxidation experiments with ambient samples in order to develop insights concerning the formation of secondary organic aerosol through gas followed by aqueous chemistry (SOAaq). Water-soluble organics (e.g., glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone) are formed through gas phase oxidation of alkene and aromatic emissions of anthropogenic and biogenic origin. Their further oxidation in clouds, fogs and wet aerosols can form lower volatility products (e.g., oligomers, organic acids) that remain in the particle phase after water evaporation, thus producing SOA. The aqueous OH radical oxidation of several individual potentially important precursors has been studied in the laboratory. In this work, we used a mist-chamber apparatus to collect atmospheric mixtures of water-soluble gases from the ambient air at San Pietro Capofiume, Italy during the PEGASOS field campaign. We measured the concentration dynamics after addition of OH radicals, in order to develop new insights regarding formation of SOA through aqueous chemistry. Specifically, batch aqueous reactions were conducted with 33 ml mist-chamber samples (TOC ~ 50-100μM) and OH radicals (~10-12M) in a new low-volume aqueous reaction vessel. OH radicals were formed in-situ, continuously by H2O2 photolysis. Products were analyzed by ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS +/-), and ESI-MS with IC pre-separation (IC/ESI-MS-). Reproducible formation of pyruvate and oxalate were observed both by IC and ESI-MS. These compounds are known to form from aldehyde oxidation in the aqueous phase. New insights regarding the aqueous chemistry of these "more atmospherically-realistic" experiments will be discussed.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  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. 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.

  15. 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

  16. Formation and emission of brominated dioxins and furans during secondary aluminum smelting processes.

    PubMed

    Wang, Mei; Liu, Guorui; Jiang, Xiaoxu; Li, Sumei; Liu, Wenbin; Zheng, Minghui

    2016-03-01

    Secondary aluminum smelting (SAl) processes have previously been found to be important sources of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). It is crucial that the key factors that influence the formation and emission of PBDD/Fs are identified to allow techniques for decreasing PBDD/F emissions during SAl processes to be developed. In this study, stack gas samples were collected from four typical secondary aluminum smelters that used different raw materials, and the samples were analyzed to allow differences between PBDD/F emissions from different SAl plants to be assessed. The composition of the raw materials was found to be one of the key factors influencing the amounts of PBDD/Fs emitted. The PBDD/F emission factors (per tonne of aluminum produced) for the plants using 100% (Plant1), 80% (Plant2), and 50% (Plant3) dirty aluminum scrap in the raw material feed were 180, 86, and 14 μg t(-1), respectively. The amounts of PBDD/Fs emitted at different stages of the smelting process (feeding-fusion, refining, and casting) were compared, and the feeding-fusion stage was found to be the main stage in which PBDD/Fs were formed and emitted. Effective aluminum scrap pretreatments could significantly decrease PBDD/F emissions. Much higher polybrominated dibenzofuran concentrations than polybrominated dibenzo-p-dioxin concentrations were found throughout the SAl process. The more-brominated congeners (including octabromodibenzo-p-dioxin, octabromodibenzofuran, heptabromodibenzo-p-dioxins, and heptabromodibenzofurans) were the dominant contributors to the total PBDD/F concentrations. The results could help in the development of techniques and strategies for controlling PBDD/F emissions during metallurgical processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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

  18. 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.

  19. 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).

  20. 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

  1. 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

  2. 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.

  3. Lumbar artery pseudoaneurysm caused by a Gunther Tulip inferior vena cava filter.

    PubMed

    Skeik, Nedaa; McEachen, James C; Stockland, Andrew H; Wennberg, Paul W; Shepherd, Roger F J; Shields, Raymond C; Andrews, James C

    2011-11-01

    Inferior vena cava (IVC) filters are widely used to decrease the risk of pulmonary embolism in patients with contraindications to anticoagulation. Complications include local hematoma, access site deep venous thrombosis (DVT), filter migration and embolization, leg penetration through the IVC wall, IVC occlusion, and filter fracture with embolization. Other rare complications include leg penetration into adjacent organs including duodenum and ureter. Lumbar artery pseudoaneurysms are rare and may be spontaneous, iatrogenic, or traumatic. To date, there have been 3 case reports of lumbar artery pseudoaneurysms caused by IVC filters. We present an additional case of a lumbar artery pseudoaneurysm caused by a Gunther Tulip IVC filter treated successfully with selective embolization.

  4. 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.

  5. Post-traumatic hepatic artery pseudoaneurysm treated with endovascular embolization and thrombin injection

    PubMed Central

    Francisco, Lloret Estañ; Asunción, López Conesa; Antonio, Capel Alemán; Ricardo, Robles Campos; Manuel, Reus Pintado; Caridad, Marín Hernández

    2010-01-01

    Post-traumatic hepatic artery pseudoaneurysm is uncommon, appearing in approximately 1% of hepatic trauma cases. Most are extrahepatic (80%) and have a late onset. Although they are usually asymptomatic, they should always be treated becasue of the high risk of complications, especially breakage. Currently the treatment of choice is endovascular embolization with coils or the exclusion of the pseudoaneurysm using other intravascular devices. Recently there have been accounts of a treatment that combines embolization with coils and image-guided percutaneous human thrombin injection. We present a case of post-traumatic hepatic artery pseudoaneurysm that was successfully treated using this combined technique. PMID:21160978

  6. Post-traumatic hepatic artery pseudoaneurysm treated with endovascular embolization and thrombin injection.

    PubMed

    Francisco, Lloret Estañ; Asunción, López Conesa; Antonio, Capel Alemán; Ricardo, Robles Campos; Manuel, Reus Pintado; Caridad, Marín Hernández

    2010-02-27

    Post-traumatic hepatic artery pseudoaneurysm is uncommon, appearing in approximately 1% of hepatic trauma cases. Most are extrahepatic (80%) and have a late onset. Although they are usually asymptomatic, they should always be treated becasue of the high risk of complications, especially breakage. Currently the treatment of choice is endovascular embolization with coils or the exclusion of the pseudoaneurysm using other intravascular devices. Recently there have been accounts of a treatment that combines embolization with coils and image-guided percutaneous human thrombin injection. We present a case of post-traumatic hepatic artery pseudoaneurysm that was successfully treated using this combined technique.

  7. 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

  8. 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

  9. 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

  10. Aortoesophageal Fistula and Aortic Pseudoaneurysm Induced by Swallowed Fish Bone: A Report of Two Cases

    SciTech Connect

    Chen Aiping Yu Hong; Li Huimin; Xiao Xiangsheng Liu Shiyuan

    2011-02-15

    Esophageal perforation caused by accidental swallowing of fish bones can lead to rare complications, such as aortoesophageal fistula accompanied by aortic pseudoaneurysm, which can be fatal if not properly handled. We report two rare cases of aortoesophageal fistula and aortic pseudoaneurysm caused by esophagus perforation after accidental swallow of fish bone; the patients also had purulent mediastinitis and esophagitis. The treatment of aortic pseudoaneurysm was successful in both cases, with one patient undergoing surgical resection and aortic neoplasty and the other patient undergoing endovascular stent graft placement. Long-term antibiotic treatment was administered to both patients after surgery. There were no postsurgical complications, and the patients recovered without incident.

  11. 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

  12. 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

  13. Regional-scale modeling of secondary organic aerosol formation downwind from the DWH oil spill

    NASA Astrophysics Data System (ADS)

    Ahmadov, R.; McKeen, S. A.; Bahreini, R.; Brioude, J.; de Gouw, J. A.; Middlebrook, A. M.; Murphy, D. M.; Pollack, I. B.; Robinson, A. L.; Ryerson, T. B.; Trainer, M.; Warneke, C.

    2010-12-01

    In response to the Deepwater Horizon (DWH) oil spill disaster in the Gulf of Mexico, the NOAA P3 aircraft performed two flights over the Gulf of Mexico during 8th and 10th of June 2010 with multiple flight legs around the DWH site to quantify the atmospheric impact of the oil spill. The measurements detected high concentrations of volatile organic compounds (VOCs) and organic aerosols (OA) downwind of the spill site. Spatial characteristics of the observed OA distribution indicated a moderate secondary organic aerosol (SOA) formation in narrow plumes coincident with high concentrations of aromatic VOCs, and also a much broader and larger SOA plume somewhat removed from the spill site. These patterns can qualitatively be explained by a dependence of VOC species volatility on the distance to the DWH spill site, and SOA yield differences associated with lower volatility (C12-C20 alkanes) versus higher volatility VOC (C7-C11 alkanes and aromatics) that comprise the bulk of the spilled oil reaching the surface. In order to test this SOA formation hypothesis the WRF-CHEM model has been applied to the Gulf of Mexico for the period of P3 aircraft operations. Modifications to the original WRF-Chem formulation include the addition of hexadecane (n-C16) within the gas-phase mechanism, and a new volatility basis set approach to simulate SOA formation using the most recent SOA yields from available literature. Emissions of NOx and C6-C11 VOC species are constrained from the P3 aircraft observations. The model has been run with different horizontal resolutions, and different emission scenarios for C12-C20 VOCs that were inferred from the composition of oil collected near the DWH. Model results for SOA and total PM2.5 aerosol are compared with the observations collected aboard the P3 aircraft, and coastal PM2.5 monitors positioned downwind of the DWH spill site, in order to test the veracity of the model formulation and help constrain the conceptual model of SOA formation from

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. Investigation of formation and ageing of biogenic secondary aerosols by soft ionization aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Müller, Lars; Reinnig, Marc-Christopher; Vogel, Alexander; Mentel, Thomas; Tillmann, Ralf; Schlosser, E.; Wahner, Andreas; Donahue, Neil; Saathoff, Harald; Hoffmann, Thorsten

    2010-05-01

    The knowledge of the chemical composition of secondary organic aerosol is one essential key to understand the significance and fate of SOA in the atmosphere. However, the chemical evolution of SOA, from the very first condensing/nucleating molecules to the final oxidation products is still insufficiently understood and object of current research [1-3]. Consequently, the formation and photochemical ageing of secondary organic aerosol (SOA) was investigated in a series of reaction chamber experiments by applying on-line aerosol mass spectrometry (atmospheric pressure chemical ionization mass spectrometry (APCI/MS)) as well as off-line high performance liquid chromatography mass spectrometry (HPLC-MS). In a set of experiments, performed in the large outdoor reaction chamber SAPHIR (Jülich, Germany), SOA was generated from a boreal mixture of biogenic VOCs. During a two-day experiment the generated biogenic SOA was exposed to OH-radicals and the temporal evolution of the chemical composition was characterized. The applied on-line MS method not only provides highly time resolved chemical information (such as an AMS) but also allows molecular identification/quantification of specific marker compounds. Several first and higher generation BSOA products were identified. Among the higher generation products, especially a tricarboxylic acid (3-methyl-1,2,3-butanetricarboxylic acid) [2] was observed as an eye-catching oxidative processing marker. A more detailed investigation of hydroxyl radical induced SOA aging at the AIDA chamber facility in Karlsruhe, again using terpenes as SOA precursors, clearly showed that the formation of the tricarboxylic acid takes place in the gas phase by the reaction of semivolatile first generation products and hydroxyl radicals. Actually, there were no indications for OH induced oxidation of compounds in the condensed phase. The consequences of these results will be discussed in the contribution. 1. Rudich, Y., N.M. Donahue, and T.F. Mentel

  20. 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

  1. Investigation of a Particle into Liquid Sampler to Study the Formation & Ageing of Secondary Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Munoz, A.; Vazquez, M.; Rodenas, M.; Vera, T.; Borrás, E.

    2012-12-01

    The atmospheric oxidation of Volatile Organic Compounds (VOCs) in the presence of NOx results in the formation of tropospheric ozone and Secondary Organic Aerosol (SOA) [Hallquist et al., 2009]. Whilst SOA is known to affect both climate and human health, the VOC oxidation pathways leading to SOA formation are poorly understood [Solomon et al., 2007]. This is in part due to the vast number and the low concentration of SOA species present in the ambient atmosphere. It has been estimated as many as 10,000 to 100,000 VOCs have been detected in the atmosphere, all of which can undergo photo-chemical oxidation and contribute to SOA formation [Goldstein and Galbally, 2007]. Atmospheric simulation chambers such as the EUropean PHOtoREactor (EUPHORE) in Valencia, Spain, are often used to study SOA formation from a single VOC precursor under controlled conditions. SOA composition and formation can be studied using online techniques such as Aerosol Mass Spectrometry (AMS), which provide high time resolution but limited structural information [Zhang et al., 2007]. Offline techniques, such as collection onto filters, extraction and subsequent analysis, provide detailed SOA composition but only usually one or two samples per experiment. In this work we report time resolved SOA composition analysis using a Particle into Liquid Sampler (PILS) followed by Liquid Chromatography Ion-Trap Mass Spectrometry (LC-IT-MS/MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS/MS). Experiments were performed at EUPHORE investigating the formation and composition of Methyl Chavicol SOA. Methyl Chavicol (also known as Estragole) was identified as the highest floral emission from an oil palm plantation in Malaysian Borneo and has also been observed in US pine forests [Bouvier-Brown et al., 2009; Misztal et al., 2010]. Previous studies indicate a high SOA yield from Methyl Chavicol at around 40 % [Lee et al., 2006], however currently there have been very few literature

  2. 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

  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.

    2015-08-01

    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.

  4. 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.

  5. 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

    2017-09-01

    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. Copyright © 2017 Elsevier B.V. All rights reserved.

  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. 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

  8. Primary Emission and the Potential of Secondary Aerosol Formation from Chinese Gasoline Engine Exhaust

    NASA Astrophysics Data System (ADS)

    Hu, Min; Peng, Jianfei; Qin, Yanhong; Du, Zhuofei; Li, Mengjin; Zheng, Rong; Zheng, Jing; Shang, Dongjie; Lu, Sihua; Wu, Yusheng; Zeng, Limin; Guo, Song; Shao, Min; Wang, Yinhui; Shuai, Shijin

    2017-04-01

    Along with the urbanization and economic growth, vehicle population in China reached 269 million, ranked the second in the world in 2015. Gasoline vehicle is identified to be the main source for urban PM2.5 in China, accounting for 15%-31%. In this study the impact of fuel components on PM2.5 and volatile organic compounds (VOCs) emissions from a gasoline port fuel injection (PFI) engine and a gasoline direct injection (GDI) engine are discussed. Results show that, higher proportion of aromatics, alkenes or sulfur in gasoline fuel will lead to higher PM emissions. The PM from the PFI engine mainly consists of OC and a small amount of EC and inorganic ions, while the PM discharge from the GDI engine mainly consists of EC, OM and a small amount of inorganic ions. Since the GDI engines can reduce fuel consumption and CO2 emissions, and it would become more and more popular in the near future. The characteristics of POM component, emission factors and source profile were investigated from GDI engine, particularly focused on the effect of engine speed, load and the catalyst, which will be very much helpful for source identification as source indicators. Chamber experiments were conducted to quantify the potential of secondary aerosol formation from exhaust of a PFI gasoline engine and China V gasoline fuel. During 4-5 h simulation, equivalent to10 days of atmospheric photo-oxidation in Beijing, the extreme SOA production was 426 ± 85 mg/kg fuel, with high precursors and OH exposure. 14% of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatility organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reduction of emissions of aerosol precursor gases from vehicles is essential to mediate pollution in China.

  9. 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.

  10. 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

  11. Mechanistic insights into non-IEPOX isoprene secondary organic aerosol formation utilizing measurements and modeling

    NASA Astrophysics Data System (ADS)

    D'Ambro, E.; Møller, K. H.; Kjaergaard, H.; Schobesberger, S.; Lopez-Hilfiker, F.; Liu, J.; Shilling, J.; Lee, B. H.; Thornton, J. A.

    2016-12-01

    Isoprene (C5H8) has the highest global emission rate of any non-methane volatile organic compound. As a result, isoprene has the potential to produce large quantities of secondary organic aerosol (SOA), which has implications for climate, air quality, and human health. However, the mechanisms by which isoprene forms SOA remain uncertain. We use a series of chamber experiments together with a detailed multiphase chemical model and quantum chemical calculations to improve our understanding of SOA formation from isoprene when IEPOX multiphase chemistry is suppressed. Isoprene photochemical oxidation experiments were conducted in the Pacific Northwest National Laboratory (PNNL) 10.6 m3 environmental chamber with dry ammonium sulfate seed, thus suppressing IEPOX reactive uptake and allowing for the study of the recently discovered dihydroxy dihydroperoxide (C5H12O6) formation pathway. Concentrations of radicals in the chamber, such as OH, HO2, RO2, and NO were systematically varied. We coupled a dynamic gas-particle partitioning module to the University of Leeds Master Chemical Mechanism with custom updates to reflect the non-IEPOX C5H12O6 pathway. The model reproduces the approximate quantity and time evolution of SOA in the PNNL chamber, as well as previous studies performed in different chambers. However, to explain the observed trends of C5H12O6 versus HO2 and NO concentrations, a fast isomerization rate (0.3-0.8 s-1) of the C5H11O6 peroxy radical is required and well supported by quantum chemical calculations of the corresponding rate coefficient. These calculations also suggest epoxides are a major product of the RO2 isomerization, indicating that epoxides and their related multiphase chemistry may be a general feature of the isoprene SOA system. The implications for the ability of isoprene oxidation to contribute to SOA under atmospheric conditions will be discussed.

  12. Secondary organic aerosol formation from intermediate-volatility organic compounds: cyclic, linear, and branched alkanes.

    PubMed

    Tkacik, Daniel S; Presto, Albert A; Donahue, Neil M; Robinson, Allen L

    2012-08-21

    Intermediate volatility organic compounds (IVOCs) are an important class of secondary organic aerosol (SOA) precursors that have not been traditionally included in chemical transport models. A challenge is that the vast majority of IVOCs cannot be speciated using traditional gas chromatography-based techniques; instead they are classified as an unresolved complex mixture (UCM) that is presumably made up of a complex mixture of branched and cyclic alkanes. To better understand SOA formation from IVOCs, a series of smog chamber experiments was conducted with different alkanes, including cyclic, branched, and linear compounds. The experiments focused on freshly formed SOA from hydroxyl (OH) radical-initiated reactions under high-NO(x) conditions at typical atmospheric organic aerosol concentrations (C(OA)). SOA yields from cyclic alkanes were comparable to yields from linear alkanes three to four carbons larger in size. For alkanes with equivalent carbon numbers, branched alkanes had the lowest SOA mass yields, ranging between 0.05 and 0.08 at a C(OA) of 15 μg m(-3). The SOA yield of branched alkanes also depends on the methyl branch position on the carbon backbone. High-resolution aerosol mass spectrometer data indicate that the SOA oxygen-to-carbon ratios were largely controlled by the carbon number of the precursor compound. Depending on the precursor size, the mass spectrum of SOA produced from IVOCs is similar to the semivolatile-oxygenated and hydrocarbon-like organic aerosol factors derived from ambient data. Using the new yield data, we estimated SOA formation potential from diesel exhaust and predict the contribution from UCM vapors to be nearly four times larger than the contribution from single-ring aromatics and comparable to that of polycyclic aromatic hydrocarbons after several hours of oxidation at typical atmospheric conditions. Therefore, SOA from IVOCs may be an important contributor to urban OA and should be included in SOA models; the yield data

  13. 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.

  14. 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

  15. 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

  16. 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…

  17. 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…

  18. 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 ...

  19. 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 ...

  20. 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

  1. Gasoline aromatics: a critical determinant of urban secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Peng, Jianfei; Hu, Min; Du, Zhuofei; Wang, Yinhui; Zheng, Jing; Zhang, Wenbin; Yang, Yudong; Qin, Yanhong; Zheng, Rong; Xiao, Yao; Wu, Yusheng; Lu, Sihua; Wu, Zhijun; Guo, Song; Mao, Hongjun; Shuai, Shijin

    2017-09-01

    Gasoline vehicle exhaust is an important contributor to secondary organic aerosol (SOA) formation in urban atmosphere. Fuel composition has a potentially considerable impact on gasoline SOA production, but the link between fuel components and SOA production is still poorly understood. Here, we present chamber experiments to investigate the impacts of gasoline aromatic content on SOA production through chamber oxidation approach. A significant amplification factor of 3-6 for SOA productions from gasoline exhausts is observed as gasoline aromatic content rose from 29 to 37 %. Considerably higher emission of aromatic volatile organic compounds (VOCs) using high-aromatic fuel plays an essential role in the enhancement of SOA production, while semi-volatile organic compounds (e.g., gas-phase PAHs) may also contribute to the higher SOA production. Our findings indicate that gasoline aromatics significantly influence ambient PM2. 5 concentration in urban areas and emphasize that more stringent regulation of gasoline aromatic content will lead to considerable benefits for urban air quality.

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

    PubMed

    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.

  3. 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).

  4. 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.

  5. Anthropogenic Influence on Secondary Aerosol Formation and Total Water-Soluble Carbon on Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Gioda, Adriana; Mateus, Vinicius; Monteiro, Isabela; Taira, Fabio; Esteves, Veronica; Saint'Pierre, Tatiana

    2013-04-01

    On a global scale, the atmosphere is an important source of nutrients, as well as pollutants, because of its interfaces with soil and water. Important compounds in the gaseous phase are in both organic and inorganic forms, such as organic acids, nitrogen, sulfur and chloride. In spite of the species in gas form, a huge number of process, anthropogenic and natural, are able to form aerosols, which may be transported over long distances. Sulfates e nitrates are responsible for rain acidity; they may also increase the solubility of organic compounds and metals making them more bioavailable, and also can act as cloud condensation nuclei (CCN). Aerosol samples (PM2.5) were collected in a rural and industrial area in Rio de Janeiro, Brazil, in order to quantify chemical species and evaluate anthropogenic influences in secondary aerosol formation and organic compounds. Samples were collected during 24 h every six days using a high-volume sampler from August 2010 to July 2011. The aerosol mass was determined by Gravimetry. The water-soluble ionic composition (WSIC) was obtained by Ion Chromatography in order to determine the major anions (NO3-, SO4= and Cl-); total water-soluble carbon (TWSC) was determined by a TOC analyzer. The average aerosol (PM2.5) concentrations ranged from 1 to 43 ug/m3 in the industrial site and from 4 to 35 ug/m3 in the rural area. Regarding anions, the highest concentrations were measured for SO42- (10.6 μg/m3-12.6 μg/m3); where the lowest value was found in the rural site and the highest in the industrial. The concentrations for NO3- and Cl- ranged from 4.2 μg/m3 to 9.3 μg/m3 and 3.1 μg/m3 to 6.4 μg /m3, respectively. Sulfate was the major species and, like nitrate, it is related to photooxidation in the atmosphere. Interestingly sulfate concentrations were higher during the dry period and could be related to photochemistry activity. The correlations between nitrate and non-sea-salt sulfate were weak, suggesting different sources for these

  6. 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

  7. 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.

  8. Secondary aerosol formation through photochemical reactions estimated by using air quality monitoring data in Taipei City from 1994 to 2003

    NASA Astrophysics Data System (ADS)

    Chang, Shuenn-Chin; Lee, Chung-Te

    Analyses of diurnal patterns of PM 10 in Taipei City have been performed in this study at different daily ozone maximum concentrations (O 3,max) from 1994 to 2003. In order to evaluate secondary aerosol formation at different ozone levels, CO was used as a tracer of primary aerosol, and O 3,max was used as an index of photochemical activity. Results show that when O 3,max exceeds 120 ppb, the highest photochemical formation of secondary aerosol can be found at 15:00 (local time). The produced secondary aerosol is estimated to contribute 30 μg m -3 (43%) of PM 10 concentration, and about 77% of the estimated secondary PM 10 is composed of PM 2.5. The estimated maximum concentration of secondary aerosol occurs 2-3 h later than the maximum ozone concentration. As revealed in an O 3 episode, PM 10 and PM 2.5 vary consistently with O 3 at daytime, which suggests that they are mostly secondary aerosols produced from photochemical reactions. Data collected from Taipei aerosol supersite in 2002 indicates that for all O 3 levels, summertime PM 2.5 is composed of 23%, 20%, 9%, and 7% of organic carbon, sulfate, nitrate, and elemental carbon, respectively. Aerosol number and volume size spectra are dominated by submicron particles either from pollution transport or photochemical reactions. Secondary PM 10 concentrations show increasing tendencies for the time between 15:00 and 19:00 from 1994-1996 to 2001-2003. This reveals that the abatement of secondary PM 10 becomes more important after pronounced primary PM 10 reduction in a metropolis.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Rare Post-Tonsillectomy Internal Carotid Artery Pseudoaneurysm: Management by Parent Artery Occlusion Using Detachable Balloons.

    PubMed

    Sharma, Arun; Kumar, Sanjeev; Devarajan, S Leve Joseph; Agarwal, Himanshu

    2017-10-01

    Iatrogenic cervical internal carotid artery pseudoaneurysm is a rare and potentially lethal complication following tonsillectomy. It can be complicated by thromboembolism, mass effect and eventually may rupture leading to death. Various endovascular treatment options are available for the management of these pseudoaneurysms, including coil embolization, detachable balloon occlusion, or stent graft placement. Parent artery occlusion using detachable balloons can be a therapeutic option in a subset of patients. However, evaluation of cross circulation with preprocedure balloon test occlusion is imperative in such cases.

  20. Percutaneous Injection Therapy for a Peripheral Pulmonary Artery Pseudoaneurysm After Failed Transcatheter Coil Embolization

    SciTech Connect

    Lee, Kyungwoo; Shin, Taebeom; Choi, Jinsu; Kim, Younghwan

    2008-09-15

    Coil embolization to occlude the feeding artery of a pseudoaneurysm is an effective treatment to control hemoptysis. However, a feeding artery of the pseudoaneurysm may not be identified at pulmonary angiography, resulting in a failure to obtain embolization. We describe here two cases of a Rasmussen aneurysm that was successfully treated with percutaneous injection of thrombin (case 1) and N-butyl cyanoacrylate (case 2) under ultrasonographic and fluoroscopic guidance after failed transcatheter coil embolization.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  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. Endovascular Treatment of Aorto-Iliac-Femoral Anastomotic Pseudoaneurysms: A Multicentric Study.

    PubMed

    Laganà, Domenico; Guzzardi, Giuseppe; Petullà, Maria; Martelli, Massimiliano; Ierardi, Anna Maria; Del Sette, Bruno; Carrafiello, Gian Paolo

    2017-06-08

    The purpose of this study was to assess the effectiveness of anastomotic pseudoaneurysms (APAs) endovascular treatment following aorto-iliac-femoral surgical reconstruction. We retrospectively evaluated 54 patients who underwent aorto-iliac-femoral bypass (72 APAs). Follow-up was performed with echo-color-Doppler and/or computed tomography angiography at 1, 3, and 6 months after the procedure and then yearly. We compared clinical success in terms of mortality between aortic APAs and nonaortic APAs (iliac-femoral-popliteal). Immediate technical success was 100%. No periprocedural complications occurred. Six patients died during follow-up due to causes not related to APA and 5 due to sepsis at 3 months after the procedure. Thirty-day mortality was 9% overall, and we did not register any statistically significant different between aortic APA and nonaortic APA groups. During a mean follow-up of 25.5 months (range: 3-72), we registered 3 occlusions of stent-graft leg, respectively, at 3 days, 7 days, and 24 months after the procedure, 2 type I endoleaks and 1 type III endoleak. Primary clinical success rate was 87.2%, and secondary clinical success was 95.7%. Endovascular treatment resulted as a valid alternative to open surgery and could be proposed as the treatment of choice for APAs especially in patients with a high surgical risk. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 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.

  8. 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

  9. Intrusive growth of primary and secondary phloem fibres in hemp stem determines fibre-bundle formation and structure

    PubMed Central

    Snegireva, Anastasia; Chernova, Tatyana; Ageeva, Marina; Lev-Yadun, Simcha; Gorshkova, Tatyana

    2015-01-01

    Plant fibres—cells with important mechanical functions and a widely used raw material—are usually identified in microscopic sections only after reaching a significant length or after developing a thickened cell wall. We characterized the early developmental stages of hemp (Cannabis sativa) stem phloem fibres, both primary (originating from the procambium) and secondary (originating in the cambium), when they still had only a primary cell wall. We gave a major emphasis to the role of intrusive elongation, the specific type of plant cell growth by which fibres commonly attain large cell length. We could identify primary phloem fibres at a distance of only 1.2–1.5 mm from the shoot apical meristem when they grew symplastically with the surrounding tissues. Half a millimeter further downwards along the stem, fibres began their intrusive elongation, which led to a sharp increase in fibre numbers visible within the stem cross-sections. The intrusive elongation of primary phloem fibres was completed within the several distal centimetres of the growing stem, before the onset of their secondary cell wall formation. The formation of secondary phloem fibres started long after the beginning of secondary xylem formation. Our data indicate that only a small portion of the fusiform cambial initials (<10 %) give rise directly or via their derivatives to secondary phloem fibres. The key determinant of final bundle structure, both for primary and secondary phloem fibres, is intrusive growth. Through bi-directional elongation, fibres join other fibres initiated individually in other stem levels, thus forming the bundles. Our results provide the specific developmental basis for further biochemical and molecular-genetic studies of phloem fibre development in hemp, but may be applied to many other species. PMID:26019229

  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.

    2014-12-01

    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

  11. 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

  12. 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

  13. ER-YAG laser pretreatment effect on in vitro secondary caries formation around composite restorations.

    PubMed

    Ceballos, L; Toledano, M; Osorio, R; García-Godoy, F; Flaitz, C; Hicks, J

    2001-02-01

    This in vitro study determined if Er-YAG laser used in instead of acid-etching influenced artificial secondary caries formation in enamel and root surfaces. Class V cavities were prepared in buccal and lingual surfaces of 10 extracted caries-free molars, with cervical margins in the root surface and occlusal margins in enamel. The specimens were randomly assigned to 2 groups: Group 1: Enamel and dentin etched with 35% phosphoric acid gel (Scotchbond 15s, rinse 10s; n=5 teeth with 2 cavities per specimen, 10 occlusal and 10 root surface margins at caries risk). Group 2: Enamel and dentin surfaces conditioned using a pulsed Er-YAG laser (KAVO) with 2.94 microm wavelength, 250 micros pulse duration, 300 mJ for enamel and 250 mJ for root surface pulse energy, 2 Hz repetition rate, and water cooling (n=5 teeth with 2 cavities per specimen, 10 occlusal and 10 root surface margins at caries risk). The cavity preparations were restored with a wet-bonding technique (Scotchbond 1 adhesive system) and a hybrid resin, light-cured composite (Z100, A3 shade), according to the manufacturer's instructions. Acid-resistant varnish was applied leaving the restoration and a 1 mm rim of adjacent surface enamel and root surface exposed. The specimens were thermocycled (5-50 degrees C, 500 cycles, dwell time 30s). Following artificial caries formation (2.2 mM calcium, 2.2 mM phosphate, 50 mM acetic acid, 5.0 mg/L fluoride, pH 4.25, 10 days), longitudinal sections (3/tooth, 30 occlusal and cervical caries risk sites per group) were taken for polarized light microscopic examination (water imbibition). Primary surface lesion depth and wall lesion frequency was determined and compared between groups (Student's t-test). Er-YAG laser irradiation resulted in a 56% reduction in primary enamel surface lesion depth (116 microm mean depth) when compared with the acid-etched group (263 microm mean depth), and a 39% decrease in root surface lesion depth (194 microm mean depth) compared with that (316

  14. Secondary organic aerosol formation from propylene irradiations in a chamber study

    NASA Astrophysics Data System (ADS)

    Ge, Shuangshuang; Xu, Yongfu; Jia, Long

    2017-05-01

    Some studies have shown that low-molecular-weight VOCs such as ethylene and acetylene can form SOA. However, so far propylene (C3H6) has not been studied. The current work systematically investigates irradiations of propylene in the presence of NOx (x = 1, 2) in a self-made indoor chamber. Only a small amount of secondary organic aerosols (SOA) was formed under 5% and 80% RH conditions without sodium chloride (NaCl) seed particles or in the presence of solid NaCl. When NaCl was in the form of droplets, liquid water content (LWC) increased from 34.5 to 169.8 μg m-3 under different initial NaCl concentrations, and correspondingly the amount of SOA linearly increased from 5.9 to 29.8 μg m-3 (SOA = 0.0164 × LWC+1.137, R2 = 0.97) at the C3H6/NOx ratio of 32.2-44.9 (ppbC/ppb). The initial C3H6/NOx concentration ratio considerably impacted the formation of SOA, in which the amount of SOA increased from 12.1 to 47.9 μg m-3 exponentially as the ratio decreased from 46.5 to 6.3 with an important point of the ratio value of 11. At the ratio of less than 11 in the regime under the control of C3H6, SOA concentrations decreased considerably with increasing ratio, whereas at the ratio value of larger than 11 in the NOx controlled regime, SOA slightly decreased with increasing ratio. From combination of the analysis of different functional groups of particles by IR spectra and ESI-Exactive-Orbitrap mass spectrometer, the constituents of SOA were identified to be hydroperoxides (e.g. HOCH2CCl(CH3)OOH), esters (e.g. CH2ClC(O)OCHClCHO), organic nitrates (e.g. HO2CH(CH2Cl)C(O)OCCl(CH2Cl)C(O)OCHClCH2ONO2), etc. Furthermore, a liquid-phase mechanism of SOA formation has been proposed in this study.

  15. 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

  16. 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.

  17. 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

  18. Source and formation of secondary particulate matter in PM2.5 in Asian continental outflow

    NASA Astrophysics Data System (ADS)

    Feng, J. L.; Guo, Z. G.; Zhang, T. R.; Yao, X. H.; Chan, C. K.; Fang, M.

    2012-02-01

    Fifty-five 48-h PM2.5 samples were collected from March 2003 to January 2004 at Changdao, a resort island in Bohai Sea/Yellow Sea in Northern China. Sulfate, nitrate and ammonium accounted for 54 ± 9% of the PM2.5 mass concentration (annual average 47 μg m-3) while organic matter and K+ contributed to 27 ± 7% and 7 ± 7% of the total mass, respectively. The ratios of SO42- to NO3- mass concentrations could be divided into two regimes and demarcated at nitrate concentration of 5 μg m-3. In the low NO3- regime, NO3-, SO42- and EC were well correlated to K+, and the estimated contributions of NO3-, SO42- and EC from biomass burning were 50 ± 27%, 38 ± 24% and 47 ± 27%, respectively. These correlations substantially decreased in the high NO3- regime reflecting fossil fuel combustion and formation of ammonium nitrate and the estimated contributions of NO3-, SO42- and EC from biomass burning were 16 ± 12%, 28 ± 18% and 27 ± 16%, respectively. In most samples, the equivalent ratios of total anion to total cation concentrations were greater than unity, suggesting that the aerosols were acidic. When [H+] > 0, a moderately good linear correlation of the estimated aerosol acidity [H+] with the water-soluble organic carbon (WSOC) was observed with R2 = 0.70 and an increase of [H+] by 100 neq m-3 would increase 1.2 μg m-3 WSOC in PM2.5. When [H+] > 0, an increase of [H+] by 100 neq m-3 would increase 1.4 μg m-3 of secondary organic carbon (SOC) in PM2.5. Moreover, the correlation analysis result suggested that 60% of the estimated SOC (on average) in PM2.5 were water-soluble.

  19. An arabinogalactan protein associated with secondary cell wall formation in differentiating xylem of loblolly pine.

    PubMed

    Zhang, Yi; Brown, Garth; Whetten, Ross; Loopstra, Carol A; Neale, David; Kieliszewski, Marcia J; Sederoff, Ronald R

    2003-05-01

    Arabinogalactan proteins (AGPs) are abundant plant proteoglycans implicated in plant growth and development. Here, we report the genetic characterization, partial purification and immunolocalization of a classical AGP (PtaAGP6, accession number AF101785) in loblolly pine (Pinus taeda L.). A PtaAGP6 full-length cDNA clone was expressed in bacteria. PtaAGP6 resembles tomato LeAGP-1 and Arabidopsis AtAGP17-19 in that they all possess a subdomain composed of basic amino acids. The accessibility of this domain in the glycoprotein makes it possible to label the PtaAGP6 epitopes on the cell surface or in the cell wall with polyclonal antibodies raised against this subdomain. The antibodies recognize the peptide of the basic subdomain and bind to the intact protein molecule. A soluble protein-containing fraction was purified from the differentiating xylem of pine trees by using beta-glucosyl Yariv reagent (beta-glcY) and was recognized by antibodies against the basic subdomain. Immunolocalization studies showed that the PtaAGP6 epitopes are restricted to a file of cells that just precede secondary cell wall thickening, suggesting roles in xylem differentiation and wood formation. The location of apparent labeling of the PtaAGP6 epitopes is separated from the location of lignin deposition. Multiple single nucleotide polymorphisms (SNPs) were detected in EST variants. Denaturing HPLC analysis of PCR products suggests that PtaAGP6 is encoded by a single gene. Mobility variation in denaturing gel electrophoresis was used to map PtaAGP6 SNPs to a site on linkage group 5.

  20. Public health impacts of secondary particulate formation from aromatic hydrocarbons in gasoline

    PubMed Central

    2013-01-01

    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 with exposures to the subset of PM2.5 that originates from vehicle emissions of aromatics under business as usual conditions. Methods The PM2.5 contribution from gasoline aromatics is estimated using the Community Multiscale Air Quality (CMAQ) modeling system and the results are compared to ambient measurements from the literature. Marginal PM2.5 annualized concentration changes are used to calculate premature mortalities using concentration-response functions, with a value of mortality reduction approach used to monetize the social cost of mortality impacts. Morbidity impacts are qualitatively discussed. Results Modeled aromatic SOA concentrations from CMAQ fall short of ambient measurements by approximately a factor of two nationwide, with strong regional differences. After accounting for this model bias, the estimated public health impacts from exposure to PM2.5 originating from aromatic hydrocarbons in gasoline lead to a central estimate of approximately 3800 predicted premature mortalities nationwide, with estimates ranging from 1800 to over 4700 depending on the specific concentration-response function used. These impacts are associated with total social costs of $28.2B, and range from $13.6B to $34.9B in 2006$. Conclusions These preliminary quantitative estimates indicate particulates from vehicular emissions of aromatic hydrocarbons demonstrate a nontrivial public health burden. The results provide a baseline from which to evaluate potential public health impacts of changes in gasoline composition. PMID:23425393

  1. 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.

  2. Formation of secondary organic aerosols from gas-phase emissions of heated cooking oils

    NASA Astrophysics Data System (ADS)

    Liu, Tengyu; Li, Zijun; Chan, ManNin; Chan, Chak K.

    2017-06-01

    Cooking emissions can potentially contribute to secondary organic aerosol (SOA) but remain poorly understood. In this study, formation of SOA from gas-phase emissions of five heated vegetable oils (i.e., corn, canola, sunflower, peanut and olive oils) was investigated in a potential aerosol mass (PAM) chamber. Experiments were conducted at 19-20 °C and 65-70 % relative humidity (RH). The characterization instruments included a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). The efficiency of SOA production, in ascending order, was peanut oil, olive oil, canola oil, corn oil and sunflower oil. The major SOA precursors from heated cooking oils were related to the content of monounsaturated fat and omega-6 fatty acids in cooking oils. The average production rate of SOA, after aging at an OH exposure of 1. 7 × 1011 molecules cm-3 s, was 1. 35 ± 0. 30 µg min-1, 3 orders of magnitude lower compared with emission rates of fine particulate matter (PM2. 5) from heated cooking oils in previous studies. The mass spectra of cooking SOA highly resemble field-derived COA (cooking-related organic aerosol) in ambient air, with R2 ranging from 0.74 to 0.88. The average carbon oxidation state (OSc) of SOA was -1.51 to -0.81, falling in the range between ambient hydrocarbon-like organic aerosol (HOA) and semi-volatile oxygenated organic aerosol (SV-OOA), indicating that SOA in these experiments was lightly oxidized.

  3. Role identification of NH3 in atmospheric secondary new particle formation in haze occurrence of China

    NASA Astrophysics Data System (ADS)

    Jiang, Binfan; Xia, Dehong

    2017-08-01

    Haze pollution in China, dominated by the aerosol particulate matters smaller than 2.5 μm (PM2.5) has raised much concern over the past decade. PM2.5 is principally derived from secondary new particulate formation (NPF) with main precursors SO2, NO2, NH3 and organic compounds (OC), where NH3 is the only alkaline inorganic gas. However, due to the lack understanding of NH3's role in NPF, few attention has been paid to NH3, which hinders the haze mitigation in China. In this work, the role of NH3 in NPF is investigated theoretically with a new kinetic model. Combining the oxidation of SO2/NO2 in SO2/NO2/NH3/H2O/air system and the aggregation of clusters in H2SO4/HNO3/NH3/OC system, this model has been established based on gas-kinetic theory, and tested upon uncertainty analysis with Monte Carlo method. The results of NPF calculations at the atmospheric concentration of each precursor show that NH3 is able to enhance NPF indirectly by facilitating conversions of SO2 and NO2, and directly by promoting aggregations of H2SO4, HNO3, NH3 and OC. The major effect of NH3 on NPF is found to be the enhancement of conversion fractions for SO2 and NO2 during oxidation processes. In addition, the promotion in contribution of HNO3 to NPF due to NH3 has been particularly observed. Therefore, controlling the emission of NH3 strictly as current restrictions on SO2 and NOx is reasonable to mitigating the haze pollution in China which has much higher atmospheric NH3 concentration over the global average level.

  4. Impacts of crystal metal on secondary aliphatic amine aerosol formation during dust storm episodes in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Qingyang; Bei, Yiling

    2016-03-01

    Trimethylamine (TMA) enters the atmosphere from a variety of sources and is a ubiquitous atmospheric organic base. The atmospheric reaction mechanism of TMA with key atmospheric oxidants is important to predict its distribution and environmental behavior in the particle phase. While previous studies have extensively focused on the production of particle amine salts (i.e. trimethylamine-N-oxide (TMAO)) using chamber experiments, the atmospheric behavior of TMAO in the environment is still poorly understood. Ambient fine particulate matter (PM2.5) was collected at two sampling sites in Beijing from March 10 to May 10, 2012. We analyzed the samples for water-soluble ions, crystal metals, TMA, and TMAO. Water-soluble ions (e.g. SO42-, NO3-, NH4+), TMA, and TMAO were measured using ion chromatography, while crystal metal (e.g. Al, Fe, Mn) in PM2.5 was quantified by inductively coupled plasma mass spectrometry (ICP-MS). Two dust storms (DS) occurred during the sampling period on March 28 and April 28. Mineral dust impacted PM2.5 mass and composition greatly during dust storm days, as it contributed approximately 1.2-4.0 times greater on dust storm days versus non-dust storm days. We found TMAO concentrations were highly associated with aluminum in PM2.5. Further, we applied the density functional theory (DFT) method to confirm that aluminum plays a catalytic effect in the reaction of TMA with ozone (O3). Our work improves understanding of the effect of crystal metals on secondary aliphatic amine aerosol formation in the atmosphere.

  5. Variability in the primary emissions and secondary gas and particle formation from vehicles using bio-ethanol mixtures.

    PubMed

    Gramsch, E; Papapostolou, V; Reyes, F; Vásquez, Y; Castillo, M; Oyola, P; López, G; Cádiz, A; Ferguson, S; Wolfson, M; Lawrence, J; Koutrakis, P

    2017-10-11

    Bioethanol for use in vehicles is becoming a substantial part of global energy infrastructure because it is renewable and some emissions are reduced. Carbon monoxide (CO) emissions and total hydrocarbons (THC) are reduced but there is still controversy regarding emissions of nitrogen oxides (NOx), aldehydes and ethanol, this may be a concern because all these compounds are precursors of ozone and secondary organic aerosol (SOA). The amount of emissions depends on the ethanol content, but also may depend on the engine quality and ethanol origin. Thus, a photochemical chamber was used to study secondary gas and aerosol formation from two flex-fueled vehicles using different ethanol blends in gasoline. One vehicle and the fuel used were made in USA and the others were made in Brazil. Primary emissions of total hydrocarbons (THC), CO, carbon dioxide (CO2), and non-methane hydrocarbons (NMHC) from both vehicles decreased as the amount of ethanol in gasoline increased. NOx emissions in the American and Brazilian car decreased with ethanol content. However, emissions of THC, CO and NOx from the Brazilian car were markedly higher than those from the U. S. car showing high variability between vehicle technologies. In the Brazilian car, formation of secondary nitrogen dioxide (NO2) and ozone (O3) was lower for higher ethanol content in the fuel. In the American car, NO2 and O3 had a small increase. Secondary particle (PM) formation in the chamber decreased for both vehicles as the fraction of ethanol in fuel increased, consistent with previous studies. Secondary to primary PM ratios for pure gasoline is 11, also consistent with previous studies. In addition, the time required to form secondary PM is longer for higher ethanol blends. These results indicate that using higher ethanol blends may have a positive impact on air quality. The use of bio-ethanol can significantly reduce petroleum use and greenhouse gas emissions worldwide. Given the extent of its use, it is important

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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 secondary phase at grain boundary of flash-sintered BaTiO3.

    PubMed

    Uehashi, Akinori; Sasaki, Katsuhiro;