CFD-FSI simulation of vortex-induced vibrations of a circular cylinder with low mass-damping

Borna, Amir,Habashi, Wagdi G.,McClure, Ghyslaine,Nadarajah, Siva K. Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.16 No.5

A computational study of vortex-induced transverse vibrations of a cylinder with low mass-damping is presented. An Arbitrary Lagrangian-Eulerian (ALE) formulation of the Unsteady Reynolds-Averaged Navier-Stokes equations (URANS), along with the Spalart-Allmaras (SA) one-equation turbulence model, are coupled conservatively with rigid body motion equations of the cylinder mounted on elastic supports in order to study the amplitude and frequency response of a freely vibrating cylinder, its flow-induced motion, Vortex Street, near-wake flow structure, and unsteady loading in a moderate range of Reynolds numbers. The time accurate response of the cylinder from rest to its limit cycle is studied to explore the effects of Reynolds number on the start of large displacements, motion amplitude, and frequency. The computational results are compared with published physical experiments and numerical studies. The maximum amplitudes of displacements computed for various Reynolds numbers are smaller than the experimental values; however, the overall agreement of the results is quite satisfactory, and the upper branch of the limit-cycle displacement amplitude vs. reduced velocity response is captured, a feature that was missed by other studies. Vortex shedding modes, lock-in phenomena, frequency response, and phase angles are also in agreement with experiments.

CFD-FSI simulation of vortex-induced vibrations of a circular cylinder with low mass-damping

Amir Borna,Wagdi G. Habashi,Ghyslaine McClure,Siva K. Nadarajah 한국풍공학회 2013 Wind and Structures, An International Journal (WAS Vol.16 No.5

A computational study of vortex-induced transverse vibrations of a cylinder with low mass-damping is presented. An Arbitrary Lagrangian-Eulerian (ALE) formulation of the Unsteady Reynolds-Averaged Navier-Stokes equations (URANS), along with the Spalart-Allmaras (SA) one-equation turbulence model, are coupled conservatively with rigid body motion equations of the cylinder mounted on elastic supports in order to study the amplitude and frequency response of a freely vibrating cylinder, its flow-induced motion, Vortex Street, near-wake flow structure, and unsteady loading in a moderate range of Reynolds numbers. The time accurate response of the cylinder from rest to its limit cycle is studied to explore the effects of Reynolds number on the start of large displacements, motion amplitude, and frequency. The computational results are compared with published physical experiments and numerical studies. The maximum amplitudes of displacements computed for various Reynolds numbers are smaller than the experimental values; however, the overall agreement of the results is quite satisfactory, and the upper branch of the limit-cycle displacement amplitude vs. reduced velocity response is captured, a feature that was missed by other studies. Vortex shedding modes, lock-in phenomena, frequency response, and phase angles are also in agreement with experiments.

Statistical Approach to Discovery of Factors Impacting on Emergence of Blood Cancers in Iran

Zand, Ali Mohammad,Imani, Saber,Saadati, Mojtaba,Ziaei, Robabeh,Borna, Hojat,Zaefizadeh, Mohammad,Shazad, Babak Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12

Cancer is now the main cause of increasing mortality throughout the world. Minor alterations in the cell cycle which are inherited and not removed by apoptosis are important rsik factors. Blood cancers are asmong the types which most readily cause death. Here in this study, usual but important factors such as age, gender, Rh and ABO blood typing, weight, and platelet counts are analyzed for impact on blood cancers. Frequencies and distributions, correlations and chi-square test were utilized in order to clarify the perspective of important factors. Our statistical results show males and females to have same risk in blood cancer but A blood type (40%) along with positive Rh (73%) had the highest risk. Low platelet counts are related to more than 80% of cases. Obesity has a statistically ignorable role in blood cancer prevalence. The fact that blood cancer cases increase during the second decade of life (45.7%) which might be because of involvement of maturation processes.

Preoperative short course radiotherapy with concurrent and consolidation chemotherapies followed by delayed surgery in locally advanced rectal cancer: preliminary results

Mahdi Aghili,Sarvazad Sotoudeh,Reza Ghalehtaki,Mohammad Babaei,Borna Farazmand,Mohammad-Sadegh Fazeli,Amir Keshvari,Peiman Haddad,Farshid Farhan 대한방사선종양학회 2018 Radiation Oncology Journal Vol.36 No.1

Purpose: This study aimed to assess complications and outcomes of a new approach, that is, combining short course radiotherapy (SRT), concurrent and consolidative chemotherapies, and delayed surgery. Materials and Methods: In this single arm phase II prospective clinical trial, patients with T3-4 or N+ M0 rectal adenocarcinoma were enrolled. Patients who received induction chemotherapy or previous pelvic radiotherapy were excluded. Study protocol consisted of three-dimensional conformal SRT (25 Gy in 5 fractions in 1 week) with concurrent and consolidation chemotherapies including capecitabine and oxaliplatin. Total mesorectal excision was done at least 8 weeks after the last fraction of radiotherapy. Primary outcome was complete pathologic response and secondary outcomes were treatment related complications. Results: Thirty-three patients completed the planned preoperative chemoradiation and 26 of them underwent surgery (24 low anterior resection and 2 abdominoperineal resection). Acute proctitis grades 2 and 3 were seen in 11 (33.3%) and 7 (21.2%) patients, respectively. There were no grades 3 and 4 subacute hematologic and non-hematologic (genitourinary and peripheral neuropathy) toxicities and perioperative morbidities such as anastomose leakage. Grade 2 or higher late toxicities were observed among 29.6% of the patients. Complete pathologic response was achieved in 8 (30.8%) patients who underwent surgery. The 3-year overall survival and local control rates were 65% and 94%, respectively. Conclusion: This study showed that SRT combined with concurrent and consolidation chemotherapies followed by delayed surgery is not only feasible and tolerable without significant toxicity but also, associated with promising complete pathologic response rates.

Preoperative short course radiotherapy with concurrent and consolidation chemotherapies followed by delayed surgery in locally advanced rectal cancer: preliminary results

Aghili, Mahdi,Sotoudeh, Sarvazad,Ghalehtaki, Reza,Babaei, Mohammad,Farazmand, Borna,Fazeli, Mohammad-Sadegh,Keshvari, Amir,Haddad, Peiman,Farhan, Farshid The Korean Society for Radiation Oncology 2018 Radiation Oncology Journal Vol.36 No.1

Purpose: This study aimed to assess complications and outcomes of a new approach, that is, combining short course radiotherapy (SRT), concurrent and consolidative chemotherapies, and delayed surgery. Materials and Methods: In this single arm phase II prospective clinical trial, patients with T3-4 or N+ M0 rectal adenocarcinoma were enrolled. Patients who received induction chemotherapy or previous pelvic radiotherapy were excluded. Study protocol consisted of three-dimensional conformal SRT (25 Gy in 5 fractions in 1 week) with concurrent and consolidation chemotherapies including capecitabine and oxaliplatin. Total mesorectal excision was done at least 8 weeks after the last fraction of radiotherapy. Primary outcome was complete pathologic response and secondary outcomes were treatment related complications. Results: Thirty-three patients completed the planned preoperative chemoradiation and 26 of them underwent surgery (24 low anterior resection and 2 abdominoperineal resection). Acute proctitis grades 2 and 3 were seen in 11 (33.3%) and 7 (21.2%) patients, respectively. There were no grades 3 and 4 subacute hematologic and non-hematologic (genitourinary and peripheral neuropathy) toxicities and perioperative morbidities such as anastomose leakage. Grade 2 or higher late toxicities were observed among 29.6% of the patients. Complete pathologic response was achieved in 8 (30.8%) patients who underwent surgery. The 3-year overall survival and local control rates were 65% and 94%, respectively. Conclusion: This study showed that SRT combined with concurrent and consolidation chemotherapies followed by delayed surgery is not only feasible and tolerable without significant toxicity but also, associated with promising complete pathologic response rates.

Patient Satisfaction in Spine Surgery: A Systematic Review of the Literature

Joshua York Menendez,Nidal Bassam Omar,Gustavo Chagoya,Borna Ethan Tabibian,Galal Ashraf Elsayed,Beverly Claire Walters,Barton Lucius Guthrie,Mark Norman Hadley 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.6

Patient satisfaction reflects the patients’ perception of the outcome of care and is being considered for use in future reimbursement schemes. No consensus exists regarding the best instrument to measure patient satisfaction in the field of spine surgery. This systematic review aimed to determine how patient satisfaction for spine surgery has been measured previously and whether a disease-specific, comprehensive instrument to measure patient satisfaction has been established; we also aimed to define the dimensions of care that determine patient satisfaction in spine surgery. A systematic search of three online databases, unpublished sources, and citations was undertaken to identify 156 empirical studies that reported on patient satisfaction in the field of spine surgery. Manuscripts were reviewed in terms of the patient satisfaction instrument used, and the instruments were categorized as per content and method axes. Taxonomy of patient satisfaction with spine surgery identified the major characteristics of providers and medical care that influenced patient satisfaction and acted as a structure to categorically define the dimensions of patient satisfaction in spine surgery. The reviewed studies predominantly used global (108/156) rather than multidimensional (46/156), instruments. Most studies (96.2%) reported satisfaction with outcome rather than with care, and only 18.5% of the studies (29/156) utilized a disease-specific instrument. The following seven dimensions of patient status, outcome, and care experience that affected patient satisfaction were identified: pain, function, patient expectations/preference, specific patient health characteristics, caregiver interpersonal manner, efficacy/clinical outcomes, and postoperative care/therapy. Currently, no disease-specific instrument that includes all dimensions of patient satisfaction in spine surgery has been developed. Such a patient satisfaction instrument should be designed, tested for reliability and validity, and widely implemented.