Journal articles: 'Acom'

1

Huang, Min, Fred Bernd Oppermann-Sanio, and Alexander Steinbüchel. "Biochemical and Molecular Characterization of theBacillus subtilis Acetoin Catabolic Pathway." Journal of Bacteriology 181, no. 12 (June 15, 1999): 3837–41. http://dx.doi.org/10.1128/jb.181.12.3837-3841.1999.

Full text

Abstract:

ABSTRACT A recent study indicated that Bacillus subtiliscatabolizes acetoin by enzymes encoded by the acu gene cluster (F. J. Grundy, D. A. Waters, T. Y. Takova, and T. M. Henkin, Mol. Microbiol. 10:259–271, 1993) that are completely different from those in the multicomponent acetoin dehydrogenase enzyme system (AoDH ES) encoded by aco gene clusters found before in all other bacteria capable of utilizing acetoin as the sole carbon source for growth. By hybridization with a DNA probe covering acoA and acoB of the AoDH ES from Clostridium magnum, genomic fragments from B. subtilis harboring acoA, acoB,acoC, acoL, and acoR homologous genes were identified, and some of them were functionally expressed inE. coli. Furthermore, acoA was inactivated inB. subtilis by disruptive mutagenesis; these mutants were impaired to express PPi-dependent AoDH E1 activity to remove acetoin from the medium and to grow with acetoin as the carbon source. Therefore, acetoin is catabolized in B. subtilis by the same mechanism as all other bacteria investigated so far, leaving the function of the previously described acu genes obscure.

APA, Harvard, Vancouver, ISO, and other styles

2

Sekhar, Laligam N., Sabareesh K. Natarajan, Gavin W. Britz, and Basavaraj Ghodke. "Microsurgical Management of Anterior Communicating Artery Aneurysms." Operative Neurosurgery 61, suppl_5 (November 1, 2007): ONS273—ONS292. http://dx.doi.org/10.1227/01.neu.0000303980.96504.d9.

Full text

Abstract:

Abstract Objective: Aneurysms of the anterior communicating (ACOM) artery are the most frequently occurring type of ruptured intracranial aneurysms. The peculiar anatomy of the anterior communicating artery complex, its anatomic variations, and its multiple perforators, along with the deep location of these aneurysms and our difficulty accessing them, pose challenging anatomic problems in their surgical treatment. Methods: We present our operative techniques for microsurgical treatment of ACOM artery aneurysms. Special, complex situations that may arise during treatment of these aneurysms and their solutions are also discussed. We highlight the technical aspects of microsurgical clipping of ACOM artery aneurysms. Results: Operative videos are provided to illustrate the technical variations of approaching and clipping these aneurysms, the A3–A3 bypass technique, and the complexity of managing these aneurysms. Conclusion: Attention to detail is critical for successful treatment of ACOM artery aneurysms. Management of each patient must be tailored, because no one technique is suitable for all situations. Not all ACOM artery aneurysms can be coiled; therefore, the surgeon's microsurgical clipping technique is an important facet of managing these aneurysms.

APA, Harvard, Vancouver, ISO, and other styles

3

Sultan-Qurraie, Ali, Ahsan Sattar, Wled Wazni, Mazen Noufal, and Osama Zaidat. "Anterior Communicating Artery Aneurysm Treatment with the Pipeline Embolization Device: A Single-Center Experience with Long-Term Follow-Up." Interventional Neurology 6, no. 3-4 (2017): 126–34. http://dx.doi.org/10.1159/000456552.

Full text

Abstract:

Introduction: The pipeline embolization device (PED) is increasingly used in the endovascular management of cerebral aneurysms. Longitudinal data regarding safety and benefit of the PED in anterior communicating (ACOM) artery aneurysms are limited and particularly lacking in residual ACOM artery aneurysms. We report the use of the PED in 3 patients with ACOM artery aneurysms who were previously coiled. Methods: Three patients with ACOM artery aneurysms, all previously treated with coiling and with recurrence of the aneurysm neck, were treated with the PED. All obtained follow-up diagnostic cerebral angiograms at either 3 or 6 months. Results: Mean age of patients was 59 years. All patients received cerebral angiograms at a minimum of 3 months after treatment with the PED. Follow-up angiography was performed up to a mean of 10 months at which time point all cases demonstrated complete aneurysm occlusion, without any stenosis in the parent artery. Conclusion: The PED can be safely used for the treatment of ACOM artery aneurysms. Complete aneurysm obliteration can be achieved in cases refractory to endovascular coiling. These findings warrant replication in a larger data set.

APA, Harvard, Vancouver, ISO, and other styles

4

Rau, Thomas, Xing He, Prem Venugopal, Fernando Viñuela, Gary Duckwiler, and Daniel J. Valentino. "Hemodynamic Effect of Unequal Anterior Cerebral Artery Flow Rates on the Anterior Communicating Artery Bifurcation: A Computational Fluid Dynamics Study." Modelling and Simulation in Engineering 2008 (2008): 1–9. http://dx.doi.org/10.1155/2008/691982.

Full text

Abstract:

Computational fluid dynamics techniques were used to investigate the hemodynamic effect of unequal anterior cerebral artery flow rates on the anterior cerebral and anterior communicating artery (ACA-ACOM) bifurcation. Hemodynamics have long been implicated as a major factor in cerebrovascular disease. Using an idealized 2D symmetric model of the ACA-ACOM geometry, the flow field and wall shear stress (WSS) at the bifurcation regions are assessed for pulsatile inflows with left to right flow ratios of 1:1, 2:1, 3:1, and 4:1. Unequal flow rates through the ACA parent arteries result in bifurcation of the higher flow parent stream and a shifting of the impingement points along the A2-ACOM adjoining wall toward the contralateral ACA. Cross-flow through the ACOM is generally unstable and results in increased WSS at the impingement region from the higher flow parent artery and a double amplitude peak in the WSS at the contralateral bifurcation region from local recirculation effects. These results suggest that asymmetry in ACA flow rates result in increased hemodynamic stresses at the ACA-ACOM bifurcation regions and suggest a possible factor for vessel weakening and aneurysm formation.

APA, Harvard, Vancouver, ISO, and other styles

5

Borg, A., P. Grover, and A. Schmitt. "WM1-5 Predictors of retreatment of anterior communicating artery aneurysms after endovascular embolisation." Journal of Neurology, Neurosurgery & Psychiatry 90, no. 3 (February 14, 2019): e1.3-e0. http://dx.doi.org/10.1136/jnnp-2019-abn.3.

Full text

Abstract:

ObjectivesTo establish recurrence and retreatment rates of anterior communicating artery aneurysms (ACom) after endovascular embolization and the complication rate of retreatment. To establish predicting morphological characteristics that would favour surgery or endovascular coiling.DesignRetrospective review of all ACom aneurysms treated at a single neurological centre over a thirteen-year period.SubjectsPatients undergoing endovascular treatment of ACom aneurysms.MethodsAneurysm and patient characteristics were recorded for retreated patients. Analysis of retreatment predictors on imaging was made.ResultsBetween 2005 and 2018, 510 Acom aneurysms were treated, of which 456 presented with SAH and 54 were elective. Out of these, 36 underwent re-treatment. Out of the re-treated aneurysms 33 were identified from radiological follow up and three presented with a re-bleed. The complication rate from the second endovascular procedure was 5.6%. Four patients underwent surgical clipping after failed coiling. Retreatment was more likely in ruptured aneurysms. The dome shape, size (mm) and orientation, were recorded for both aneurysms requiring retreatment and aneurysms successfully excluded after the first procedure. Other parameters reported included time interval, coiling technique (balloon-assisted/stent-assisted).ConclusionsRecurrence of Acom aneurysms after coiling carries significant morbidity. Recognising predictors of recurrence would help identify those aneurysms that are better treated with surgery.

APA, Harvard, Vancouver, ISO, and other styles

6

Hula, William D., Patrick J. Doyle, Clement A. Stone, Shannon N. Austermann Hula, Stacey Kellough, Julie L. Wambaugh, Katherine B. Ross, James G. Schumacher, and Ann St. Jacque. "The Aphasia Communication Outcome Measure (ACOM): Dimensionality, Item Bank Calibration, and Initial Validation." Journal of Speech, Language, and Hearing Research 58, no. 3 (June 2015): 906–19. http://dx.doi.org/10.1044/2015_jslhr-l-14-0235.

Full text

Abstract:

Purpose The purpose of this study is to investigate the structure and measurement properties of the Aphasia Communication Outcome Measure (ACOM), a patient-reported outcome measure of communicative functioning for persons with aphasia. Method Three hundred twenty-nine participants with aphasia responded to 177 items asking about communicative functioning. The data were analyzed using a categorical item factor analysis approach. Validity of ACOM scores on the basis of their convergence with performance-based, clinician-reported, and surrogate-reported assessments of communication was also assessed. Results Fifty-nine items that obtained adequate fit to a modified bifactor measurement model and functioned similarly across several demographic and clinical subgroupings were identified. The factor model estimates were transformed to item response theory graded response model parameters, and the resulting score estimates showed good precision and moderately strong convergence with other measures of communicative ability and functioning. A free software application for administration and scoring of the ACOM item bank is available from the first author. Conclusions The ACOM provides reliable measurement of patient-reported communicative functioning in aphasia. The results supported the validity of ACOM scores insofar as (a) factor analyses provided support for a coherent measurement model, (b) items functioned similarly across demographic and clinical subgroups, and (c) scores showed good convergence with measures of related constructs.

APA, Harvard, Vancouver, ISO, and other styles

7

Wang, Xuan, Xiaoguang Tong, Jie Liu, Minggang Shi, Yanguo Shang, and Hu Wang. "Tailored Communicating Bypass for the Management of Complex Anterior Communicating Artery Aneurysms: “Flow-Counteraction” In Situ Bypass and Interposition Bypass Using Contralateral A2 Orifice as Donor Site." Operative Neurosurgery 19, no. 2 (January 24, 2020): 117–25. http://dx.doi.org/10.1093/ons/opz421.

Full text

Abstract:

Abstract BACKGROUND The use of bypass surgery for anterior communicating artery (ACOM) aneurysms is technically challenging. Communicating bypass (COMB), such as pericallosal artery side-to-side anastomosis, is the most frequently used and anatomically directed reconstruction option. However, in many complex cases, this technique may not afford a sufficient blood supply or necessitate sacrificing the ACOM and the eloquent perforators arising from it. OBJECTIVE To evaluate tailored COMB and propose a practical algorithm for the management of complex ACOM aneurysms. METHODS For 1 patient with an aneurysm incorporating the entire ACOM, conventional in Situ A3-A3 bypass was performed as the sole treatment in order to create competing flow for aneurysm obliteration, sparing the sacrifice of eloquent perforators. In situations in which A2s were asymmetric in the other case, the contralateral A2 orifice was selected as the donor site to provide adequate blood flow by employing a short segment of the interposition graft. RESULTS The aneurysm was not visualized in patients with in Situ A3-A3 bypass because of the “flow-counteraction” strategy. The second patient, who underwent implementation of the contralateral A2 orifice for ipsilateral A3 interposition bypass, demonstrated sufficient bypass patency and complete obliteration of the aneurysm. CONCLUSION The feasibility of conventional COMB combined with complete trapping may only be constrained to selected ideal cases for the treatment of complex ACOM aneurysms. Innovative modifications should be designed in order to create individualized strategies for each patient because of the complexity of hemodynamics and the vascular architecture. Flow-counteraction in Situ bypass and interposition bypass using the contralateral A2 orifice as the donor site are 2 novel modalities for optimizing the advantages and broadening the applications of COMB for the treatment of complex ACOM aneurysms.

APA, Harvard, Vancouver, ISO, and other styles

8

Dee, Hannah, and Peter Reffell. "ACOM (“computing for all”)." ACM SIGCSE Bulletin 31, no. 3 (September 1999): 195. http://dx.doi.org/10.1145/384267.305941.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Al-Khafaji, Aktham O., Zahraa F. Al-Sharshahi, Ryan P. Lee, Zahraa A. Alsubaihawi1, Ali A. Dolachee, and Samer S. Hoz. "Unilateral absence of the internal carotid artery associated with anterior communicating artery aneurysms: Systematic review and a proposed management algorithm." Surgical Neurology International 11 (August 1, 2020): 221. http://dx.doi.org/10.25259/sni_238_2020.

Full text

Abstract:

Background: Absence or hypoplasia of the internal carotid artery (ICA) is a rare congenital anomaly that is mostly unilateral and highly associated with other intracranial vascular anomalies, of which saccular aneurysm is the most common. Blood flow to the circulation of the affected side is maintained by collateral pathways, some of which include the anterior communicating artery (Acom) as part of their anatomy. Therefore, temporary clipping during microsurgery on Acom aneurysms in patients with unilateral ICA anomalies could jeopardize these collaterals and place the patient at risk of ischemic damage. In this paper, we review the literature on cases with a unilaterally absent ICA associated with Acom aneurysms and provide an illustrative case. Methods: We combined our experience of one case of a unilaterally absent ICA associated with an Acom aneurysm with the 33 existing publications on the same subject in the literature, for a total of 40 cases. We provide a detailed systematic literature review of this association of vascular anomalies, exploring different aspects regarding the collateral pathways and how they impact management strategies and propose a management algorithm to deal with such association. Results: The mean age was 48.2 ± 16.5 years. The aneurysmal rupture was the most common presentation (75%). Agenesis was observed in 70% of patients, followed by hypoplasia (20%) and, finally, aplasia (10%). Lie Type A was the most common pattern of collaterals (50%), with Types B and D being of almost equal proportions. Most aneurysms were located at the A1-Acom junction contralateral to the anomalous side (Fisher’s Exact test; P = 0.03). One case of temporary clipping was reported in the literature. Conclusion: Acom aneurysms in patients with unilateral ICA anomalies, given they are more commonly present contralaterally, could be of acquired etiology, warranting periodic screening in asymptomatic patients. Temporary clipping might be safe in patients with Type D collateral pattern, while those with Types A or B may require intraoperative rupture risk assessment and a tailored management plan to avoid disrupting collateral flow and causing ischemia.

APA, Harvard, Vancouver, ISO, and other styles

10

Hula, William D., and Patrick J. Doyle. "The Aphasia Communication Outcome Measure: Motivation, Development, Validity Evidence, and Interpretation of Change Scores." Seminars in Speech and Language 42, no. 03 (June 2021): 211–24. http://dx.doi.org/10.1055/s-0041-1730906.

Full text

Abstract:

AbstractThe Aphasia Communication Outcome Measure (ACOM) is a patient-reported measure of communicative functioning developed for persons with stroke-induced aphasia. It was motivated by the desire to include the perspective of persons with aphasia in the measurement of treatment outcomes and to apply newly accessible psychometric tools to improve the quality and usefulness of available outcome measures for aphasia. The ACOM was developed within an item response theory framework, and the validity of the score estimates it provides is supported by evidence based on its content, internal structure, relationships with other variables, stability over time, and responsiveness to treatment. This article summarizes the background and motivation for the ACOM, the steps in its initial development, evidence supporting its validity as a measure of patient-reported communication functioning, and current recommendations for interpreting change scores.

APA, Harvard, Vancouver, ISO, and other styles

11

Das, Joe M., Rashmi Sapkota, and Manish Mishra. "Transient Complete Unilateral Oculomotor Nerve Palsy following Clipping of Ruptured Anterior Communicating Artery Aneurysm: An Abstruse Phenomenon." Case Reports in Vascular Medicine 2019 (February 5, 2019): 1–5. http://dx.doi.org/10.1155/2019/3185023.

Full text

Abstract:

Background. Aneurysmal subarachnoid hemorrhage may be associated with different cranial nerve palsies, with oculomotor nerve palsy (ONP) being the most common. ONP is especially associated with posterior communicating artery aneurysms, due to the anatomical proximity of the nerve to the aneurysmal wall. Anterior communicating artery (Acom) aneurysms are very unlikely to produce ONP due to the widely separated anatomical locations of Acom and oculomotor nerve. Case Description. Here we describe the case of a 60-year-old nondiabetic lady who presented with Acom aneurysmal subarachnoid hemorrhage having a World Federation of Neurosurgical Societies (WFNS) grade I. She underwent an uneventful right pterional craniotomy and clipping of the aneurysm, except for a short period of controlled rupture of the aneurysm. Postoperatively she developed complete ONP on the right side, though her sensorium was preserved. Computed Tomogram and Magnetic Resonance Imaging scans of the brain did not yield any useful information regarding its etiology. She was conservatively managed and kept on regular follow-up. She had a gradual recovery of ONP in the following order: pupillary reaction, ocular movements, and finally ptosis. On postoperative day 61, she had complete recovery from ONP. Conclusion. We describe a very unusual case of complete ONP following Acom aneurysm clipping and its management by masterly inactivity.

APA, Harvard, Vancouver, ISO, and other styles

12

Lin, Li-Mei, Rajiv R. Iyer, Matthew T. Bender, Thomas Monarch, Geoffrey P. Colby, Judy Huang, Rafael J. Tamargo, and Alexander L. Coon. "Rescue Treatment with Pipeline Embolization for Postsurgical Clipping Recurrences of Anterior Communicating Artery Region Aneurysms." Interventional Neurology 6, no. 3-4 (2017): 135–46. http://dx.doi.org/10.1159/000460264.

Full text

Abstract:

Background: Postsurgical clipping aneurysm recurrences or residuals can be difficult to manage with either traditional open microsurgical approaches or endosaccular coiling. Endoluminal parent vessel reconstruction with flow diversion may be an ideal method for treating these recurrences by avoiding reoperative surgery or intraprocedural aneurysm rupture with aneurysm access. Method: We retrospectively reviewed a single-center aneurysm database identifying all anterior communicating artery (ACom) region aneurysms with recurrences after microsurgical clipping. Cases subsequently treated with Pipeline embolization device (PED) were identified for analysis. Results: Nine PED neurointerventions were performed for the treatment of 6 ACom region recurrent aneurysms after surgical clipping (ACom, n = 4 and A1-A2 junction, n = 2). Of the 6 aneurysms treated, 4 were previously ruptured. Mean patient age was 59.5 ± 6.9 years (range 50-67 years). Mean aneurysm size was 5.1 ± 2.2 mm (range 3-9 mm). Mean fluoroscopy time was 44.1 ± 12.4 min. A single PED, deployed from ipsilateral A2 to ipsilateral A1, was used in 6 cases. No instances of periprocedural complications were encountered. Angiographic follow-up was available in all aneurysms; 5 of these 6 (83%) demonstrated complete aneurysm occlusion. Conclusion: Flow diversion with PED can be a safe and efficacious treatment approach for recurrent ACom region aneurysms after surgical clipping.

APA, Harvard, Vancouver, ISO, and other styles

13

Chakraborty, S., N. F. Fanning, S. K. Lee, and K. G. TerBrugge. "Bilateral Infraoptic Origin of Anterior Cerebral Arteries: A Rare Anomaly and its Embryological and Clinical Significance." Interventional Neuroradiology 12, no. 2 (June 2006): 155–59. http://dx.doi.org/10.1177/159101990601200210.

Full text

Abstract:

We describe a case of bilateral infraoptic origin of the anterior cerebral arteries associated with an anterior communicating artery (ACOM) aneurysm. Anatomical variations of the anterior cerebral artery (ACA) are common; however, bilateral infraoptic course of the anterior cerebral artery is extremely rare. Since an infraoptic course of the ACA is associated with ACOM aneurysm formation, an understanding of the cerebrovascular anatomy and embryology is important for appropriate management of the aneurysm.

APA, Harvard, Vancouver, ISO, and other styles

14

Mahmud, Reaz, Mansur Habib, Sharif Uddin Khan, and Asma Khan. "Risk Factors and Morphological Differences of Ruptured Saccular Aneurysm in Different Sites of Anterior Circulation in Patients Presenting with Subarachnoid Haemorrhage." Journal of National Institute of Neurosciences Bangladesh 3, no. 1 (April 6, 2018): 21–28. http://dx.doi.org/10.3329/jninb.v3i1.36268.

Full text

Abstract:

Background: All sites of intracranial aneurysms have always been considered together in most of the studies of risk factors of aneurysm rupture. Therefore, it is not known whether some risk factors predispose to aneurysm rupture at a particular location. Morphologies also vary in accordance to different sites of the aneurysm.Objective: The purpose of the present study was to observe the differences in the risk factors, the size, aspect ratio and size ratio among the anterior circulation aneurysms.Methodology: This hospital based cross-sectional study carried out in the Department of Neurology at Dhaka Medical College Hospital (DMCH), Dhaka during July 2013 to June 2015 for a period of two (02) years. Patients with subarachnoid haemorrhage caused by ruptured anterior circulation saccular aneurysms admitted in the Departments of Neurology, Internal Medicine and Neurosurgery Departments at Dhaka Medical College Hospital (DMCH), Dhaka and the Department of Neurointervention at National Institute of Neurosciences and Hospital, Dhaka were enrolled in this study. Patients’ ≥18 years of age with subarachnoid haemorrhage caused by anterior circulation aneurysm which was confirmed by computed tomogram (CT-scan) and/or CSF study and digital subtraction angiography were included in this study. The risk factors were identified by interviewing the patients and the morphology were measured from the digital subtraction angiogram.Results: A total number of 85 patients with ruptured saccular anterior circulation aneurysm were enrolled in this study. In this study anterior communicating artery aneurysm (ACom) was the most frequent site of aneurysm (42%). The mean age of the patients with ACom aneurysm (51.72 ± 9.26 years) was significantly higher than posterior communicating artery (47.5 ± 8.2 years) aneurysm and middle cerebral artery (MCA) (43.41 ± 8.0 years) aneurysm. Above the age of 50 ACom aneurysm was the most frequent aneurysm (OR 5.5, p<0.05). Among the female Posterior communicating artery (PCom) aneurysm (46.7%) was the most frequent aneurysm and among the male ACom aneurysm (37.5%) was the most frequent aneurysm. Family history was exclusive in MCA aneurysm (3.5%). The mean size of MCA (7.79 ± 0.71 cm) was higher than ACom (6.12 ± 2.7cm) aneurysm and PCom (6.5 ± 2.4 cm) aneurysm and proportion of aneurysm >10 mm was also higher among the middle cerebral artery (35.6%) aneurysms. The size ratio was significantly higher in ACom (3.08±1.23) and MCA (3.04±0.97) aneurysm. ACom (76.4%) and MCA (83.3%) had also more frequent high risk size ratio.Conclusion: In conclusion anterior circulation aneurysms differ in respects of risk factors and morphology.Journal of National Institute of Neurosciences Bangladesh, 2017;3(1): 21-28

APA, Harvard, Vancouver, ISO, and other styles

15

Noda, Kosumo, Rokuya Tanikawa, Hiroyasu Kamiyama, Nakao Ohta, Tomonari Yabuuchi, Shirou Miyata, Akira Kosaka, Toshiyuki Tsuboi, and Sadahisa Tokuda. "Interhemispheric Approach for ACom Aneurysm." Japanese Journal of Neurosurgery 21, no. 11 (2012): 834–41. http://dx.doi.org/10.7887/jcns.21.834.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Kim, Bum Joon, Hyun Goo Kang, Byeong-Duk Kwun, Jae-sung Ahn, Jisung Lee, Sung Ho Lee, Dong-Wha Kang, Jong S. Kim, and Sun U. Kwon. "Small versus Large Ruptured Intracranial Aneurysm: Concerns with the Site of Aneurysm." Cerebrovascular Diseases 43, no. 3-4 (2017): 139–44. http://dx.doi.org/10.1159/000452347.

Full text

Abstract:

Background: Although size is one of the strongest predictors, small aneurysms often rupture. We compared the characteristics of small and large ruptured intracranial aneurysms (RIAs) according to their location to find the factors associated with small RIAs in each location. Methods: Patients with subarachnoid hemorrhage due to saccular RIAs were consecutively enrolled. The sizes were dichotomized as small (<5 mm) or large, and the location was classified as paraclinoid-distal internal carotid artery, sidewalls of anterior or middle cerebral artery (MCA; sidewall), MCA-bifurcation, anterior or posterior communicating artery (Acom or Pcom, respectively), and posterior circulation RIAs. Independent factors associated with small RIAs compared to large RIAs were investigated in each location. Results: Small RIAs were observed in 384 of 791 patients (48.5%), and were most commonly located at Acom (17.1%) followed by Pcom (9.0%) and sidewalls (7.2%). Female sex (OR 3.038; 95% CI 2.099-4.395), young age (OR 0.971; 95% CI 0.958-0.985), hypertension (OR 1.412; 95% CI 1.033-1.930) and multiple aneurysms (OR 1.942; 95% CI 1.335-2.824) were associated with small RIAs. By location, sidewall aneurysms (OR 2.183; 95% CI 1.049-4.542) were associated with small RIAs, whereas MCA-bifurcation (OR 0.318; 95% CI 0.168-0.599) and Pcom aneurysms (OR 0.511; 95% CI 0.277-0.944) were associated with large RIAs. The presence of multiple aneurysms (OR 4.69; 95% CI 1.45-21.19) was associated with small RIAs at sidewalls, and young age, female sex, hypertension and the presence of bilateral A1 (OR 1.85; 95% CI 1.09-3.13) were associated with small RIAs at Acom. Acom RIAs with bilateral A1 was smaller than those with unilateral A1 (4.7 ± 2.1 vs. 5.8 ± 2.6 mm; p < 0.001). Conclusions: Intracranial aneurysms which rupture below 5 mm are not uncommon, and the factors associated with small-sized RIAs differ according to location. Sidewall aneurysms, with multiple aneurysms and Acom aneurysms with bilateral A1 may rupture even at small size.

APA, Harvard, Vancouver, ISO, and other styles

17

Glauser, Gregory, and Omar A. Choudhri. "Microsurgical clipping of an unruptured superiorly projecting ACoM aneurysm in a rotated ACoM complex." Clinical Case Reports 7, no. 5 (March 19, 2019): 1112–13. http://dx.doi.org/10.1002/ccr3.2022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Mortimer, Alex M., Brendan Steinfort, Ken Faulder, Tian Erho, Daniel B. Scherman, Prashanth J. Rao, and Timothy Harrington. "Rates of local procedural-related structural injury following clipping or coiling of anterior communicating artery aneurysms." Journal of NeuroInterventional Surgery 8, no. 3 (February 2, 2015): 256–64. http://dx.doi.org/10.1136/neurintsurg-2014-011620.

Full text

Abstract:

BackgroundSurgical clipping and endovascular coiling yield similar functional outcomes for the treatment of saccular aneurysms of the anterior communicating (ACOM) artery. However, surgical treatment may be associated with greater rates of cognitive impairment due to injury of adjacent structures. We aimed to quantify the rates of injury (infarction/hemorrhage) for both clipping and coiling of ACOM aneurysms.MethodsThis was a retrospective dual-center radiological investigation of a consecutive series of patients with ruptured and unruptured ACOM aneurysms treated between January 2011 and October 2014. Post-treatment CT or MRI was assessed for new ischemic or hemorrhagic injury. Injury relating to the primary hemorrhage or vasospasm was differentiated. Univariate analysis using χ2 tests and multivariate analysis using binary logistic regression was used.Results66 patients treated with clipping were compared with 93 patients treated with coiling. 32/66 (48.5%) patients in the clipping group suffered treatment-related injury (31 ischemic, 1 hemorrhagic) compared with 4/93 (4.4%) patients in the coiling group (3 ischemic, 1 hemorrhagic) (p<0.0001). For patients with subarachnoid hemorrhage, the multivariate OR for infarction for clipping over coiling was 24.42 (95% CI 5.84 to 102.14), p<0.0001. The most common site of infarction was the basal forebrain (28/66 patients, 42.4%), with bilateral infarction in 4. There was injury of the septal/subcallosal region in 12/66 patients (18%).ConclusionsClipping of ACOM aneurysms is associated with significantly higher rates of structural injury than coiling, and this may be a reason for superior cognitive outcomes in patients treated with coiling in previously published studies.

APA, Harvard, Vancouver, ISO, and other styles

19

Mahmoud, M. "Rescue Stenting in Endovascular Treatment of Acutely Ruptured Cerebral Aneurysms." Interventional Neuroradiology 19, no. 1 (March 2013): 21–26. http://dx.doi.org/10.1177/159101991301900103.

Full text

Abstract:

Thromboembolic events and major artery occlusion following cerebral aneurysm coiling may lead to serious complications and even death if not treated. The use of an intracranial stent in the setting of subarachnoid hemorrhage (SAH) is risky due to the need for antiplatelet therapy. However in some conditions it could be an effective solution for this major problem. This study describes a revascularization technique using a Solitaire stent for treatment of anterior cerebral artery (ACA) occlusion following coiling of anterior communicating artery (Acom) aneurysms. Three cases of ruptured Acom aneurysms treated during the course of SAH underwent unplanned deployment of an intracranial stent. Complete occlusion of the ACA at the origin of the A2 segment developed during or shortly after coiling. Emergent CT brain scan was done in two cases to exclude rebleeding. Follow-up CT or MRI scans were performed 24 hours after stenting. Technical success was achieved in all cases. Complete revascularization of the Acom was achieved post stent deployment (TIMI grade 3). Time from onset of symptoms to full revascularization in the three cases was 35 minutes, one hour 50 minutes and two hours 40 minutes respectively. No intracranial bleeding occurred in any case following the procedure. No neurological changes occurred in case 1; mild neurological and radiological changes occurred in cases 2 and 3. Deployment of an intracranial stent achieved complete revascularization of the occluded Acom. Its use in a context of SAH is relatively risky but the technique resulted in a significant improvement of symptoms following flow restoration and probably helped prevent symptoms worsening, major disability or even death. A study on a larger patient sample with long-term follow-up will be of value.

APA, Harvard, Vancouver, ISO, and other styles

20

Hage, Ziad A., and Fady T. Charbel. "Clipping of bilateral MCA aneurysms and a coiled ACOM aneurysm through a modified lateral supraorbital craniotomy." Neurosurgical Focus 38, videosuppl1 (January 2015): Video19. http://dx.doi.org/10.3171/2015.v1.focus14604.

Full text

Abstract:

We showcase the microsurgical clipping of a left middle cerebral artery (MCA) aneurysm-(B) done through a modified right lateral supraorbital craniotomy, as well as clipping of a previously coiled anterior communicating (ACOM) artery aneurysm-(C) and a bilobed right MCA aneurysm-(A). Splitting of the right sylvian fissure is initially performed following which a subfrontal approach is used to expose and dissect the contralateral sylvian fissure. The left MCA aneurysm is identified and clipped. The ACOM aneurysm is then clipped following multiple clip repositioning based on flow measurements. The right MCA aneurysm is then identified and each lobe is clipped separately.The first picture showcased in this video is a side to side right and left ICA injection in AP projection. In this picture, (A) points to the bilobed right MCA aneurysm, (B) to the left middle cerebral artery (MCA) aneurysm, and (C) to the previously coiled anterior communicating (ACOM) artery aneurysm. The red dotted line shows that both MCA aneurysms lie within the same plane which makes it easier to clip both of them, through one small craniotomy.The video can be found here: http://youtu.be/4cQC7nHsL5I.

APA, Harvard, Vancouver, ISO, and other styles

21

Finitsis, S., R. Anxionnat, A. Lebedinsky, P. C. Albuquerque, M. F. Clayton, L. Picard, and S. Bracard. "Endovascular Treatment of ACom Intracranial Aneurysms." Interventional Neuroradiology 16, no. 1 (March 2010): 7–16. http://dx.doi.org/10.1177/159101991001600101.

Full text

Abstract:

The immediate and long-term outcomes, complications, recurrences and the need for retreatment were analyzed in a series of 280 consecutive patients with anterior communicating artery aneurysms treated with the endovascular technique. From October 1992 to October 2001 280 patients with 282 anterior communicating artery aneurysms were addressed to our center. For the analysis, the population was divided into two major groups: group 1, comprising 239 (85%) patients with ruptured aneurysms and group 2 comprising of 42 (15%) patients with unruptured aneurysms. In group 1, 185 (77.4%) patients had a good initial pre-treatment Hunt and Hess grade of I-III. Aneurysm size was divided into three categories according to the larger diameter: less than 4 mm, between 4 and 10 mm and larger than 10 mm. The sizes of aneurysms in groups 1 and 2 were identical but a less favorable neck to depth ratio of 0.5 was more frequent in group 2. Endovascular treatment was finally performed in 234 patients in group 1 and 34 patients in group 2. Complete obliteration was more frequently obtained in group 2 unlike a residual neck or opacification of the sac that were more frequently seen in group 1. No peri-treatment complications were recorded in group 2. In group 1 the peri-treatment mortality and overall peri-treatment morbidity were 5.1% and 8.1% respectively. Eight patients (3.4%) in group 1 presented early post treatment rebleeding with a mortality of 88%. The mean time to follow-up was 3.09 years. In group 1, 51 (21.7%) recurrences occurred of which 14 were minor and 37 major. In group 2, eight (23.5%) recurrences occurred, five minor and three major. Two patients (0.8%) presented late rebleeding in group 1. Twenty-seven second endovascular retreatments were performed, 24 (10.2%) in group 1 and three (8.8%) in group 2, seven third endovascular retreatments and two surgical clippings in group 1 only. There was no additional morbidity related to retreatments. Endovascular treatment is an effective method for the treatment of anterior communicating artery aneurysms allowing late rebleeding prevention. Peri-treatment rebleeding warrants caution in anticoagulation management. This is a single center experience and the follow-up period is limited. Patients should be followed-up in the long-term as recurrences may occur and warrant additional treatment.

APA, Harvard, Vancouver, ISO, and other styles

22

Garge, ShaileshkumarS, DevshiR Visana, PoojaD Vyas, PranavD Modi, SanditiN Poyam, and Sharad Ghatge. "Actively leaking ruptured acom aneurysm: Fountain sign." Neurology India 62, no. 2 (2014): 234. http://dx.doi.org/10.4103/0028-3886.132454.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Garcia, Alessandro, Phil Greenwood, George Heineman, Robert Walker, Yuanfang Cai, Hong Yul Yang, Elisa Baniassad, Cristina Videira Lopes, Christa Schwanninger, and Jianjun Zhao. "Assessment of Contemporary Modularization Techniques - ACoM'07." ACM SIGSOFT Software Engineering Notes 32, no. 5 (September 2007): 31–37. http://dx.doi.org/10.1145/1290993.1291005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Takahashi, Koji, Meguru Kaminoyama, and Yutaka Tada. "Preface to the Special Issue for ACOM." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 42, no. 11 (2009): 788. http://dx.doi.org/10.1252/jcej.421100.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Tomita, Hideyuki, and Katsuya Saito. "A difficult-to-treat Acom aneurysm with the combined vascular anomaly of Acom fenestration and accessory anterior cerebral artery." Surgical Neurology International 9, no. 1 (2018): 67. http://dx.doi.org/10.4103/sni.sni_4_18.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Thomas, Joshua D., and Kenneth B. Sloan. "In vitro evaluation of alkylcarbonyloxymethyl (ACOM) ethers as novel prodrugs of phenols for topical delivery: ACOM prodrugs of acetaminophen." International Journal of Pharmaceutics 346, no. 1-2 (January 4, 2008): 80–88. http://dx.doi.org/10.1016/j.ijpharm.2007.06.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

H., Zafar Ahmed, and Paresh Sodhiya. "A study of outcome of surgical management of ruptured intracranial aneurysms." International Surgery Journal 5, no. 5 (April 21, 2018): 1697. http://dx.doi.org/10.18203/2349-2902.isj20181449.

Full text

Abstract:

Background: The present study is a retrospective analysis of collected data of consecutive cases with ruptured intracranial aneurysms treated at two centres. The clinical outcome and associated complications were graded using the modified Rankins scale.Methods: A total of 48 patients of ruptured intracranial aneurysms were managed between January 2014 and August 2017. All forty eight patients underwent clipping. All the 48 patients who were consequently treated with surgery for intracranial aneurysm were analysed.Results: Of the total of 48 patients, Six patients died in the post-operative period while the remaining 42 patients were available for a minimum followup of 6 months duration. the post operatives outcomes matched the presenting Hunt and Hess grade in 80% patients.Conclusions: Surgical outcome of ICA Aneurysm is generally good. Poor results are mainly related to poor aneurysm grade, atherosclerotic intracranial carotid artery, and severe vasospasm. ACOM aneurysm in spite of being very common the outcome of patients with ACOM aneurysms remains not so good. In patients with MCA aneurysm the post-operative outcome is significantly better if surgery is undertaken earlier.

APA, Harvard, Vancouver, ISO, and other styles

28

Kobler, Aaron, Jochen Lohmiller, Jonathan Schäfer, Michael Kerber, Anna Castrup, Ankush Kashiwar, Patric A. Gruber, Karsten Albe, Horst Hahn, and Christian Kübel. "Deformation-induced grain growth and twinning in nanocrystalline palladium thin films." Beilstein Journal of Nanotechnology 4 (September 24, 2013): 554–66. http://dx.doi.org/10.3762/bjnano.4.64.

Full text

Abstract:

The microstructure and mechanical properties of nanocrystalline Pd films prepared by magnetron sputtering have been investigated as a function of strain. The films were deposited onto polyimide substrates and tested in tensile mode. In order to follow the deformation processes in the material, several samples were strained to defined straining states, up to a maximum engineering strain of 10%, and prepared for post-mortem analysis. The nanocrystalline structure was investigated by quantitative automated crystal orientation mapping (ACOM) in a transmission electron microscope (TEM), identifying grain growth and twinning/detwinning resulting from dislocation activity as two of the mechanisms contributing to the macroscopic deformation. Depending on the initial twin density, the samples behaved differently. For low initial twin densities, an increasing twin density was found during straining. On the other hand, starting from a higher twin density, the twins were depleted with increasing strain. The findings from ACOM-TEM were confirmed by results from molecular dynamics (MD) simulations and from conventional and in-situ synchrotron X-ray diffraction (CXRD, SXRD) experiments.

APA, Harvard, Vancouver, ISO, and other styles

29

Rauch, Edgar F., Patrick Harrison, and Muriel Véron. "New Features in Crystal Orientation and Phase Mapping for Transmission Electron Microscopy." Symmetry 13, no. 9 (September 11, 2021): 1675. http://dx.doi.org/10.3390/sym13091675.

Full text

Abstract:

ACOM/TEM is an automated electron diffraction pattern indexing tool that enables the structure, phase and crystallographic orientation of materials to be routinely determined. The software package, which is part of ACOM/TEM, has substantially evolved over the last fifteen years and has pioneered numerous additional functions with the constant objective of improving its capabilities to make the tremendous amount of information contained in the diffraction patterns easily available to the user. Initially devoted to the analysis of local crystallographic texture, and as an alternative to both X-ray pole figure measurement and EBSD accessories for scanning electron microscopes, it has rapidly proven itself effective to distinguish multiple different phases contained within a given sample, including amorphous phases. Different strategies were developed to bypass the inherent limitations of transmission electron diffraction patterns, such as 180° ambiguities or the complexity of patterns produced from overlapping grains. Post processing algorithms have also been developed to improve the angular resolution and to increase the computing rate. The present paper aims to review some of these facilities. On-going works on 3D reconstruction are also introduced.

APA, Harvard, Vancouver, ISO, and other styles

30

Nepal, Pankaj Raj, Dinesh Kumar Thapa, Robin Bhattrai, and Jagat Narayan Rajbanshi. "Fenestrated A1 in Ruptured Anterior Communicating Artery Aneurysm: A Case Report." Eastern Green Neurosurgery 2, no. 3 (September 24, 2020): 29–31. http://dx.doi.org/10.3126/egn.v2i3.31463.

Full text

Abstract:

There is a lot of variation around the anterior communicating artery (Acom) and various classification systems have been quoted many times in literatures. Here we have reported a rare case of a 52-year-old woman who had ruptured Acomartery aneurysm. The angiography also showed a fenestration of the A1 segment of anterior cerebral artery.

APA, Harvard, Vancouver, ISO, and other styles

31

Ostafin, M., Jan Pospiech, and Robert A. Schwarzer. "Microstructure and Texture in Copper Sheets after Reverse and Cross Rolling." Solid State Phenomena 105 (July 2005): 309–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.105.309.

Full text

Abstract:

The objectives of this investigation are structural effects in electrolytic copper sheets which are caused by the change of the direction of rolling. Unidirectional, reverse as well as cross-rolling at 90° respectively at 45° to the precedent rolling direction have been applied down to final deformations as low as 80% reduction in thickness. Texture has been determined by ACOM (Automated Crystal Orientation Measurement, “Automated EBSD”) in the SEM and by X-ray pole figure measurement. The main benefits of ACOM are a high spatial resolution which enables the investigation of texture gradients from the mid plane to the surface of the sheet, and the visualization of the microstructure by crystal orientation mapping. In addition to local texture, statistical distributions of misorientations across grain boundaries and of S grain boundaries have been derived from the individual grain orientation data. The change of the path of plastic deformation induces a destabilization of the substructure which is formed during the primary step of unidirectional rolling. A distinct change of texture is found depending on the deformation process. In cross rolling, the b fiber changes into the unstable b90 fiber which almost disappears with progressive deformation along the new rolling direction.

APA, Harvard, Vancouver, ISO, and other styles

32

Hendricks, Benjamin K., and Robert F. Spetzler. "Recurrent Giant Anterior Cerebral Artery (ACA) Aneurysm With Previous Coiling, Attempted Clipping Then Direct ACA-to-ACA Bypass: 2-Dimensional Operative Video." Operative Neurosurgery 18, no. 4 (January 15, 2020): E110. http://dx.doi.org/10.1093/ons/opz415.

Full text

Abstract:

Abstract Giant aneurysms are defined as lesions with a widest diameter of 2.5 cm or greater and account for 2% to 5% of all intracranial aneurysms. These lesions are challenging entities for microsurgical management with techniques such as direct aneurysmal neck clipping, aneurysm neck reconstructions, aneurysmotomy, and aneurysmectomy. This patient had a previously coiled, unruptured, superiorly projecting giant anterior communicating artery (ACom) aneurysm, eccentric toward the left, for which surgical intervention was undertaken. A left orbitozygomatic craniotomy was performed, and a temporary clip was applied to the bilateral proximal A1 segments. Aneurysmotomy was then performed with internal debulking of the aneurysmal thrombus. Aneurysmectomy and removal of the coil mass were performed. Next, the aneurysm neck was reconstructed using multiple surgical clips. After anticipated aneurysm neck reconstruction, indocyanine green (ICG) angiography demonstrated a lack of flow in the ipsilateral A2. The ACom was then transected along the aneurysm neck, and an end-to-end anastomosis of the distal A1 and proximal A2 was performed. Repeat ICG angiography demonstrated patency of the A1-A2 anastomosis. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

APA, Harvard, Vancouver, ISO, and other styles

33

De Araújo Júnior, Antônio Santos, Paulo Henrique Pires De Aguiar, Mirella Martins Fazzito, Renata Simm, Apio Claudio Martins Antunes, Carlos Alexandre Zicarelli, and Marco Stefani. "Use of temporary arterial occlusion during anterior cerebral artery aneurysm repair." JBNC - JORNAL BRASILEIRO DE NEUROCIRURGIA 23, no. 4 (March 28, 2018): 275–80. http://dx.doi.org/10.22290/jbnc.v23i4.1205.

Full text

Abstract:

Introduction: This study was undertaken to determine variables that could predict, in the perioperative period of anterior communicating artery (ACom) aneurysms surgeries, the likelihood of postoperative sequelae and complications, after temporary arterial occlusion. Patients and Methods: In a universe of 92 patients submitted to ACom aneurysm clipping between 2000 and 2013, 32 were operated in the last seven years. Among these patients, 21 needed temporary arterial occlusion during surgical aneurysm repair, and had their data examined retrospectively. Results: Aneurysms larger than 7mm were more likely to be treated with longer temporary clipping time than small aneurysms, <7mm (22±5.7 vs 11.3±4.1, t-Test, p <0.0001). There was no statistical correlation between time of occlusion and outcome (r=0.92, Pearson, p>0.08). Age, Glasgow Coma Scale (GCS) at initial evaluation, and Fisher scale at 1st CT scanning were independent factors of unfavorable outcome (Glasgow Outcome Scale ≤ 3) (cox-regression, p<0.001). Among variable factors, patients older than 50 years, an initial GCS under 13, and a Fisher grade III or IV resulted in worse outcome. Meanwhile gender, tobacco or alcohol addiction, obesity, arterial hypertension, dyslipidemia, location of temporary occlusion (A1 or A2), intraoperative rupture and the aneurysm size were not identified as independent prognostic factors. During follow-up period, two thirds of the patients had a favorable outcome (GOS ≥ 4), accomplishing normal daily life activities without major complications. Fifty-two percent of patients evolved with hydrocephalus, despite of routine fenestration of the lamina terminalis, performed in 71.4% of procedures. Most patients also developed clinical vasospasm (66.6%), with 19% of the patients presenting with a severe disease. Delayed ischemic neurological deficit was observed in 28.5%, secondary to severe vasospasm, and without any statistical correlation to time of temporary occlusion or intraoperative aneurysm rupture. Conclusion: Temporary clipping during ACom aneurysm repair does not seem to add more morbidities to the procedure, and is not an independent prognostic factor. However, age, initial GCS and Fisher grade are associated to unfavorable outcome.

APA, Harvard, Vancouver, ISO, and other styles

34

Songsaeng, Dittapong, Sonti Nummeesri, and Sukanya Krueklang. "Successful Endovascular Coiling of Ruptured Anterior Communicating Aneurysm (aCom)." Bangkok Medical Journal 14, no. 01 (February 18, 2018): 87. http://dx.doi.org/10.31524/bkkmedj.2018.02.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Schwarzer, R. A. "Spatial Resolution in ACOM - What Will Come After EBSD." Microscopy Today 16, no. 1 (January 2008): 34–37. http://dx.doi.org/10.1017/s1551929500054316.

Full text

Abstract:

Automated Crystal Orientation Microscopy (ACOM) on a grain specific level has proved to be an invaluable new tool for characterizing polycrystalline materials. It is usually based on scanning facilities using electron diffraction , due to its high sensitivity and spatial resolution, but also attempts have been made which rely upon X-ray or hard synchrotron radiation diffraction. The grain orientations are commonly mapped in pseudo-colors on the scanning grid to construct Crystal Orientation Maps (COM), which represent “images” of the microstructure with the advantage of providing quantitative orientation contrast. In a similar way, misorientations across grain boundaries, Σ values of grain boundaries, or other microstructural characteristics are visualized by mapping the grains in the micrograph with specific colors. The principal objectives are the determination of quantitative, statistically meaningful data sets of crystal orientations, misorientations, the CSL character (Σ) of grain boundaries, local crystal texture (pole figures, ODF, MODF, OCF) and derived entities, phase discrimination and phase identification.

APA, Harvard, Vancouver, ISO, and other styles

36

Schwarzer, R. A., and A. Huot. "The Study of Microstructure on a Mesoscale by ACOM." Crystal Research and Technology 35, no. 6-7 (July 2000): 851–62. http://dx.doi.org/10.1002/1521-4079(200007)35:6/7<851::aid-crat851>3.0.co;2-n.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Wu, Jun, Roumen Petrov, Sebastian Kölling, Paul Koenraad, Loic Malet, Stephane Godet, and Jilt Sietsma. "Micro and Nanoscale Characterization of Complex Multilayer-Structured White Etching Layer in Rails." Metals 8, no. 10 (September 23, 2018): 749. http://dx.doi.org/10.3390/met8100749.

Full text

Abstract:

Micro- to nano-scale characterization of the microstructures in the white etching layer (WEL), observed in a Dutch R260 Mn grade rail steel, was performed via various techniques. Retained austenite in the WEL was identified via electron backscatter diffraction (EBSD), automatic crystallographic orientation mapping in transmission electron microscopy (ACOM-TEM), and X-ray diffraction (XRD). EBSD and ACOM-TEM methods were used to quantify grains (size range: 50 nm–4 μm) in the WEL. Transmission electron microscopy (TEM) was used to identify complex heterogeneous microstructural morphologies in the WEL: Nano-twinning substructure with high dislocation density in the WEL close to the rail surface and untransformed cementite and dislocations in the WEL close to the pearlite matrix. Furthermore, atom probe tomography (APT) revealed a heterogeneous through-thickness distribution of alloying elements in the WEL. Accordingly, the WEL is considered a multi-layered martensitic microstructure. These findings are supported by the temperature calculations from the shape analysis of the manganese profile from APT measurements, related to manganese diffusion. The deformation characteristics of the WEL and the pearlite beneath the WEL are discussed based on the EBSD measurements. The role of deformation in the martensitic phase transformation for WEL formation is discussed.

APA, Harvard, Vancouver, ISO, and other styles

38

Kashiwar, Ankush, Horst Hahn, and Christian Kübel. "In Situ TEM Observation of Cooperative Grain Rotations and the Bauschinger Effect in Nanocrystalline Palladium." Nanomaterials 11, no. 2 (February 9, 2021): 432. http://dx.doi.org/10.3390/nano11020432.

Full text

Abstract:

We report on cooperative grain rotation accompanied by a strong Bauschinger effect in nanocrystalline (nc) palladium thin film. A thin film of nc Pd was subjected to cyclic loading–unloading using in situ TEM nanomechanics, and the evolving microstructural characteristics were investigated with ADF-STEM imaging and quantitative ACOM-STEM analysis. ADF-STEM imaging revealed a partially reversible rotation of nanosized grains with a strong out-of-plane component during cyclic loading–unloading experiments. Sets of neighboring grains were shown to rotate cooperatively, one after the other, with increasing/decreasing strain. ACOM-STEM in conjunction with these experiments provided information on the crystallographic orientation of the rotating grains at different strain levels. Local Nye tensor analysis showed significantly different geometrically necessary dislocation (GND) density evolution within grains in close proximity, confirming a locally heterogeneous deformation response. The GND density analysis revealed the formation of dislocation pile-ups at grain boundaries (GBs), indicating the generation of back stresses during unloading. A statistical analysis of the orientation changes of individual grains showed the rotation of most grains without global texture development, which fits to both dislocation- and GB sliding-based mechanisms. Overall, our quantitative in situ experimental approach explores the roles of these different deformation mechanisms operating in nanocrystalline metals during cyclic loading.

APA, Harvard, Vancouver, ISO, and other styles

39

Kiyofuji, Satoshi, Tomohiro Inoue, Akira Tamura, and Isamu Saito. "Combined interhemispheric and pterional approach for ACOM and left MCA aneurysms." Neurosurgical Focus 38, videosuppl1 (January 2015): Video15. http://dx.doi.org/10.3171/2015.v1.focus14559.

Full text

Abstract:

This video demonstrates combined two separate craniotomies for two difficult unruptured cerebral aneurysms. The anterior communicating artery (ACOM) aneurysm existed at a high position, projected posteriorly, and thus necessitated an interhemispheric approach. Left middle cerebral artery (MCA) aneurysm with complex figure was treated through a separate pterional approach. Meticulous micro-cisternal opening under high magnification enabled safe and effective exposure of both aneurysms with minimal brain retraction, which alleviated brain damage as shown in postoperative images.The video can be found here: http://youtu.be/mBYsaAVekCA.

APA, Harvard, Vancouver, ISO, and other styles

40

Delgadillo Grajeda, Arnoldo. "Burkholder, Arno, La red de los espejos. Una historia del diario Excélsior, 1916-1976, México, Fondo de Cultura Económica (FCE), 2016, 187 pp., ISBN: 978–607-16-3720-8." Revista de Historia de América, no. 156 (January 30, 2019): 331–33. http://dx.doi.org/10.35424/rha.156.2019.246.

Full text

Abstract:

Excélsior es el tercer periódico más antiguo del país, y en la actualidad uno de los más importantes de México. Fue fundado por Rafael Alducin, acom-pañado en su trinchera por más de 30 periodistas de la época; su primer número circuló el 18 de marzo de 1917. Actualmente pertenece al empresa-rio Olegario Vázquez Raña, es dirigido por Ernesto Rivera Aguilar, y forma parte del Grupo Imagen, que integra también radio, televisión y mediosdigitales.

APA, Harvard, Vancouver, ISO, and other styles

41

Bosscher, Ph M. "J.J. van Dijk, Strategie of eigen weg? ACOM 1982-2002." BMGN - Low Countries Historical Review 118, no. 3 (January 1, 2003): 444. http://dx.doi.org/10.18352/bmgn-lchr.5936.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Honna, Masao, Hisashi Matsunaga, and Hiromu Nakazawa. "Development of Adaptive Companion Robot Based on Human Satisfaction (ACOM)." IFAC Proceedings Volumes 33, no. 12 (June 2000): 15–18. http://dx.doi.org/10.1016/s1474-6670(17)37266-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Waqar, M., and A. H. Vohra. "Sudden collapse in a middle-aged male: giant ACOM aneurysm." Case Reports 2013, oct18 1 (October 18, 2013): bcr2013201711. http://dx.doi.org/10.1136/bcr-2013-201711.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Chowdhury, Md Tauhidul Islam, Mohammad Shah Jahirul Hoque Chowdhury, Mohammad Sadekur Rahman Sarkar, KM Ahasan Ahmed, Md Nazmul Kabir, Mohammad Rezaul Haque, Fahmida Rouf, et al. "Computed Tomography Angiography (CTA) Evaluation of Spontaneous Subarachnoid Hemorrhage." Journal of National Institute of Neurosciences Bangladesh 6, no. 2 (December 13, 2020): 78–81. http://dx.doi.org/10.3329/jninb.v6i2.50745.

Full text

Abstract:

Background: In evaluation of non-traumatic subarachnoid hemorrhage CT angiography (CTA) has 97-98% sensitivity and near 100% specificity. Objective: This study was conducted to evaluate the CTA findings of CT positive non traumatic subarachnoid hemorrhage. Methodology: This is an observational cross sectional study performed in Neurology department of National Institute of Neurosciences and Hospital, Dhaka over one year period (January 2019 to December 2019). Total 87 CT positive subarachnoid hemorrhage cases were purposively included in this study. All CT positive patients underwent CTA of Cerebral vessels for further evaluation. The angiography were evaluated by competent neuro-radiologists blinded about the study. Result: Among 87 patients, 40.2% were male and 59.8% were female. The average age was 53.33±11.1 years. Among the studied patient the source of bleeding was found 78.16% aneurysmal and 21.84% non-aneurysmal. 85.30% patients had single aneurysm and 14.70% had multiple aneurysm. The highest number of patient had Acom aneurysm (41.17%) followed by MCA (22.05%), ICA (13.23%), ACA (7.35%) and vertebral artery (1.14%) in order of frequency. Among the multiple aneurysm group most of the patients had combination of Acom, MCA and ICA aneurysm. Conclusion: From this study, we can conclude that CTA can be used as the primary diagnostic tool in evaluation of spontaneous SAH. Journal of National Institute of Neurosciences Bangladesh, 2020;6(2): 78-81

APA, Harvard, Vancouver, ISO, and other styles

45

Fierstra, Jorn, Jan Karl Burkhardt, Stamatios Stamou, Luca Regli, and Oliver Bozinov. "Twin-like appearance of an unruptured intracerebral anterior communicating artery (ACom) aneurysm in a male sibling of a patient with a ruptured ACom aneurysm." Acta Neurochirurgica 158, no. 6 (April 1, 2016): 1051–55. http://dx.doi.org/10.1007/s00701-016-2782-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Nagata, Kazuya. "2.Surgery for the anterior communicating artery aneurysm based on the anatomical backgroun." Japanese Journal of Neurosurgery 12, no. 4 (2003): 264. http://dx.doi.org/10.7887/jcns.12.264_2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Nie, Xianzhou, Rudra P. Singh, and George C. C. Tai. "Molecular characterization and expression analysis of 1-aminocyclopropane-1-carboxylate oxidase homologs from potato under abiotic and biotic stresses." Genome 45, no. 5 (October 1, 2002): 905–13. http://dx.doi.org/10.1139/g02-062.

Full text

Abstract:

In this work, we report cloning of two full-length 1-aminocyclopropane-1-carboxylate oxidase (ACO) cDNAs (ACO1 and ACO2) from potato (Solanum tuberosum) and their expression in potato tissues. The sequence data indicate that the two cDNAs share a high degree of homology with each other, and with known ACO genes from other plant species, including monocots and dicots. However, these potato genes lack homology at the 5' and 3' ends, despite similarities in their open reading frames and encoded amino acids. Phylogenetic analysis places them in two subfamilies of ACOs. The genes are tissue specific: expression is high in leaves and low in roots and tubers. In sprouts and tubers, ACO1 is induced by heat (40°C) and cold (0°C) stresses, whereas ACO2 is induced only by cold (0°C). ACO1 is markedly induced in leaves by wounding, soil-flooding, and exogenous application of 1-aminocyclopropane-1-carboxylic acid (ACC). In contrast, ACO2 induction is lower under these treatments. ACO1 and ACO2 are regulated very differently in potato leaves with respect to senescence. ACO2 expression is unaffected by senescence, whereas that of ACO1 is closely related to the age and senescence in both attached and detached leaves. Exogenous ACC not only induces ACO1, but also accelerates leaf senescence. ACO1 transcripts are induced significantly in leaves, stems, and tubers in the Potato virus A (PVA)-resistant potato cultivar Shepody when graft inoculated with PVA.Key Words: ACO, ethylene, gene isolation, phylogeny, Solanum tuberosum.

APA, Harvard, Vancouver, ISO, and other styles

48

Tai, Alexander X., Kenneth D. Sack, Aalap Herur-Raman, and Walter C. Jean. "The Benefits of Limited Orbitotomy on the Supraorbital Approach: An Anatomic and Morphometric Study in Virtual Reality." Operative Neurosurgery 18, no. 5 (July 23, 2019): 542–50. http://dx.doi.org/10.1093/ons/opz201.

Full text

Abstract:

Abstract BACKGROUND Cadaveric studies on surgical anatomy and approaches are hampered by the limited number of specimens. Virtual reality (VR) technology can overcome this limitation, allowing for more in-depth statistical analysis of the data. OBJECTIVE To determine the benefit of a supraorbital ridge osteotomy in a supraorbital craniotomy targeting (1) the anterior communicating artery complex (ACOM), and (2) a lesion 25 mm above tuberculum sellae, using a large dataset generated by VR. METHODS Computed tomography scans of 30 subjects without cranial osseous pathology were identified for use with VR technology. After correlating VR and DICOM datasets, supraorbital craniotomies were simulated without and with removal of supraorbital ridge, bilaterally (n = 60). Area of freedom (AOF) from the outer table to the targets and the vertical center angle (VCA) to targets were calculated, before and after the orbitotomy. RESULTS For the ACOM, AOF averaged 496 mm2 (range: 322-805) and increased 8.9% to an average of 547 mm2 with the removal of the supraorbital ridge (P < .001). VCA increased from 18.5 to 20.3 degrees. For the suprasellar target, AOF averaged 507 mm2 (range 324-772) and increased 42.5% to 722 mm2 after orbitotomy (P < .001). VCA increased from 22.1 to 30.8 degrees. CONCLUSION VR technology is an emerging tool to study neurosurgical approaches. Here, we demonstrate with VR that the removal of the supraorbital ridge in a supraorbital craniotomy affords greater access to superiorly located lesions of the anterior fossa floor; however, deeper and lower lesions require a more aggressive orbital roof osteotomy to widen the exposure.

APA, Harvard, Vancouver, ISO, and other styles

49

Doong, Joe-Yuan H., and Yun-Tzu Kiang. "Inheritance of aconitase isozymes in soybean." Genome 29, no. 5 (October 1, 1987): 713–17. http://dx.doi.org/10.1139/g87-122.

Full text

Abstract:

A six-band electrophoretic zymogram for aconitase was observed in mature soybean seeds. Among 750 Glycine max (L.) Merr. strains and cultivars examined, 10 zymogram types were identified. Genetic studies showed that the second band (Rf's of 0.35 or 0.42) and the fourth band (Rf's of 0.61, 0.63, or 0.69) in the zymograms were the products of two unlinked loci, Aco2 and Aco4, with two and three codominant alleles, respectively. Heterozygotes displayed both parental band sets without any intermediate band, indicating a monomeric structure for aconitase. The most common alleles at the two loci were Aco2-b (0.793) and Aco4-c (0.818). Linkage analyses revealed that both Aco2 and Aco4 loci are inherited independently of four other biochemical loci (Adh1, Am3, Ap, Dial). Key words: aconitase, isozymes, electrophoresis, gene locus, soybean, Glycine max.

APA, Harvard, Vancouver, ISO, and other styles

50

Nzogang, Billy Clitton, Manuel Thieme, Alexandre Mussi, Sylvie Demouchy, and Patrick Cordier. "Characterization of recovery onset by subgrain and grain boundary migration in experimentally deformed polycrystalline olivine." European Journal of Mineralogy 32, no. 1 (January 15, 2020): 13–26. http://dx.doi.org/10.5194/ejm-32-13-2020.

Full text

Abstract:

Abstract. To apprehend plate tectonics and the dynamics of the lithosphere–asthenosphere boundary, composed principally of olivine, we need to understand the mechanisms that control plastic deformation of olivine in the relevant temperature domain. After more than 50 years of laboratory studies and investigations on natural rocks, the interplay of several key parameters (e.g. temperature, pressure, vacancy concentration, dislocation densities, grain size, strain rate) controlling polycrystalline olivine plasticity remains difficult to assess. Here, we study four olivine polycrystals, which have been deformed in axial compression under a confining pressure of 300 MPa, at 1273 or 1473 K. Despite significant differences in mechanical properties (stress–strain curves), previous characterization by scanning (SEM) and transmission electron microscopy (TEM) did not reveal significant differences in dislocation microstructures which could explain these contrasted behaviours. We have undertaken automatic crystallographic orientation mapping (ACOM) analyses in TEM to increase the spatial resolution of characterization compared to previously obtained electron backscatter diffraction maps to further decipher the microstructures at nanoscale. With this novel technique applied to olivine, a noticeable difference in the onset of microstructural recovery has been identified between specimens deformed at 1273 and 1473 K. The microstructures of the olivine polycrystals deformed at 1473 K exhibit numerous curved grain and subgrain boundaries, advocating for recovery by boundary migration. In contrast, the microstructures of the olivine polycrystals deformed at 1273 K have significantly fewer subgrain boundaries and show more straight boundaries (i.e. closer to an equilibrium microstructure) than in the specimen deformed at 1473 K. Characterization by ACOM-TEM has permitted the identification of the onset of recovery, which is led by boundary migration even for very low macroscopic finite strains.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Acom'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles