98 results on '"Ahmad, Y."'
Search Results
2. Game theoretic solution for an Unmanned Aerial Vehicle network host under DDoS attack
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Mairaj, Aakif and Javaid, Ahmad Y.
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- 2022
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3. The effect of re-pressing and glazing on the optical properties of high-density micronized heat-pressed glass ceramic.
- Author
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Al-Dabbagh, Raghad A., Imam, Ahmad Y., Baik, Khadijah M., Eldemellawy, Mohamed, and El-Etreby, Amr
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SURFACE roughness , *OPTICAL properties , *CRYSTAL structure , *TWO-way analysis of variance , *THERMOCYCLING - Abstract
Recycling high-density micronized (HDM) heat-press glass ceramic ingots to press several restorations would be economical and reduce waste. However, to achieve this, the effects of re-pressing on the optical properties and long-term durability of HDM glass ceramics must be completely understood. The aim of this study was to assess the effects of re-pressing and glazing on the optical properties of HDM heat-press glass ceramic. Twenty-one HDM glass ceramic (Initial LiSi Press) discs were prepared and randomly divided into three groups (n = 7 per group): single heat pressing, double heat pressing, and triple heat pressing. Optical properties, surface roughness, and crystalline structure were measured for each group at three time points: before glazing and thermocycling, after glazing, and after thermocycling. The effect of these independent variables on optical properties were assessed by two-way ANOVA, and Tukey's post hoc test assessed the differences between groups. Heat re-pressing HDM glass ceramic significantly altered its color, reduced translucency, and reduced surface roughness (P < 0.001). After the second heat-press, the color (ΔΕ 00) and translucency parameter changes (ΔTP 00) exceeded perceptible thresholds but not clinically acceptable thresholds, but these were exceeded after the third press for ΔΕ 00. Additionally, glazing lightened the shade of the ceramic, reduced translucency, and reduced surface roughness (P < 0.001), with ΔΕ 00 and ΔTP 00 changes exceeding the perceptible but not the clinically acceptable threshold. Thermocycling produced ΔTP 00 changes that exceeded the clinically acceptable threshold. Further studies of the effects of heat re-pressing on HDM glass ceramic are now needed to progress toward clinical translation. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
4. Carbon in lithium-ion and post-lithium-ion batteries: Recent features
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Ahmad, Y., Colin, M., Gervillie-Mouravieff, C., Dubois, M., and Guérin, K.
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- 2021
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5. Role of pharmacists in the care of adult asthma patients: A scoping review.
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Mahmoud, Aseel, Abuhelwa, Ahmad Y., Owen, Tom, Alazzawi, Amad, Shara, Mohd, Alqudah, Mohammad A.Y., ElHajj, Maguy Saffouh, and Smith, Jane R.
- Abstract
Asthma is a common long-term condition that affects people of all ages. Evidence suggests that a significant proportion of asthma patients in the Gulf Cooperation Council (GCC) do not receive appropriate diagnosis, monitoring and/or treatment. When inadequately treated, asthma can negatively affect quality of life and may lead to hospitalisation and death. Although pharmacists play a role in asthma care globally, there appears to be no defined role for pharmacists in providing care to patients with asthma in the GCC countries. This scoping review aims to review and summarise studies conducted in the GCC countries involving pharmacists in the management of adults with asthma or evaluating pharmacists' asthma care knowledge and/or skills. A systematic scoping review was undertaken. Seven databases were searched using relevant search terms for articles published up to May 2023. Studies that evaluated pharmacists roles, knowledge and skills in providing asthma care to adults in the United Arab Emirates (UAE), Qatar, Kuwait, Oman, Saudi Arabia, and Bahrain were considered eligible for inclusion. Extracted data were collated using tables and used to produce narrative descriptive summaries. Out of the 1588 search results, only seven studies met the inclusion criteria. Of those, only one developed and tested a pharmacist-led inhaler technique educational intervention in the UAE within community pharmacy setting for asthma patients. The remaining six studies assessed community pharmacists knowledge in providing asthma management and patient education in UAE, Saudi Arabia and Qatar. The quality of the included studies varied with four relying on simulated patients to assess pharmacists knowledge. The study that tested the intervention suggested improvement in inhaler technique and asthma symptoms control after receiving the intervention. The findings suggest a need to improve pharmacists knowledge of inhaler technique demonstration (mainly Metered Dose Inhalers), asthma management advice and assessment of asthma control and medication use. This review highlights a lack of research on pharmacist-led asthma interventions and identifies training needs to enable pharmacists to be involved in asthma care in the GCC countries. Future research could develop approaches involving pharmacists to improve asthma care and outcomes in the region. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Application specific drone simulators: Recent advances and challenges
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Mairaj, Aakif, Baba, Asif I., and Javaid, Ahmad Y.
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- 2019
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7. Invariant characterization of third-order ordinary differential equations [formula omitted] with five-dimensional point symmetry group
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Al-Dweik, Ahmad Y., Mahomed, F.M., and Mustafa, M.T.
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- 2019
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8. An alternative proof of Lie’s linearization theorem using a new [formula omitted]-symmetry criterion
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Al-Dweik, Ahmad Y., Mustafa, M.T., Mara’Beh, Raed A., and Mahomed, F.M.
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- 2015
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9. Noether symmetries and conservation laws of wave equation on static spherically symmetric spacetimes with higher symmetries
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Mustafa, M.T. and Al-Dweik, Ahmad Y.
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- 2015
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10. An efficient compression scheme based on adaptive thresholding in wavelet domain using particle swarm optimization
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Ahmadi, Kaveh, Javaid, Ahmad Y., and Salari, Ezzatollah
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- 2015
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11. Structure control at the nanoscale in fluorinated graphitized carbon blacks through the fluorination route
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Ahmad, Y., Disa, E., Guérin, K., Dubois, M., Petit, E., Hamwi, A., Thomas, P., and Mansot, J.-L.
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- 2014
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12. Real-world effectiveness of COVID-19 vaccines: A retrospective cohort study of vaccinated individuals in Jazan, Saudi Arabia.
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Elamin, Mohammed Y., Maslamani, Yahya A., Muaddi, Mohammed A., Alameer, Anwar A., Alqassim, Ahmad Y., Doweri, Abrar A., Zaylaee, Mutaz M., Rayani, Hussain Y., Darraj, Abdulaziz Y., Hejri, Yehya M., Dahlan, Abdu A., and Gosadi, Ibrahim M.
- Abstract
COVID-19 (Coronavirus Disease 2019) vaccinations are a critical control measure for the coronavirus pandemic that began in 2019. Several COVID-19 vaccines have been developed, and their effectiveness will almost certainly vary. This study aimed to assess how effective two doses of the Pfizer and Oxford-AstraZeneca vaccines were in preventing SARS‐CoV‐2 infection six months after administration. This is a retrospective cohort study of adult individuals from the Jazan Region of Saudi Arabia who received their second dose of the COVID-19 vaccine [Pfizer and Oxford-AstraZeneca (ASZ)] between April and June 2021. The monitoring and follow-up period continued until the end of January 2022. Data were retrieved from the Health Electronic Surveillance Network and National Vaccination Records. Logistic regression was performed to assess the risk of COVID-19 infection among the vaccinated subjects. This study included randomly enrolled 4458 participants in Jazan who received two doses of the COVID-19 vaccine during the research period. The majority of them received the Pfizer vaccine (3136/4458; 70.3%), while the remaining received the ASZ vaccine (1322/4458; 29.7%). The study participants' mean age was 59.7 years, with a male-to-female ratio of 1.9:1.0 (2920:1538). The results showed that the Pfizer and ASZ vaccines' protection against infection decreased from 93.2% and 90.2%, respectively, during the first three months, to 68.5% and 68.1% after a six-month interval. In the current study population, being Saudi Arabian, younger as well as having longer intervals between vaccines or crossing a 6-month period after the second vaccine dose were factors linked to higher rates of breakthrough infections. Our findings revealed variations in the efficacy of different COVID-19 vaccine types against COVID-19 breakthrough infections. The Pfizer (mRNA-based) vaccine was found to be relatively more effective than the ASZ (DNA-based) vaccine. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Transcatheter Aortic Valve Replacement in Patients at High Risk of Coronary Obstruction
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Ahmad, Y., Oakley, L., Yoon, S., Kaewkes, D., Chakravarty, T., Patel, C., Palmerini, Tullio, Bruno, A. G., Saia, Francesco, Testa, L., Bedogni, Francesco, Chieffo, Alaide, Montorfano, M., Bartorelli, A. L., Porto, Italo, Grube, E., Nickenig, G., Sinning, J. -M., De Carlo, M., Petronio, A. S., Barbanti, M., Tamburino, C., Iadanza, A., Burzotta, Francesco, Trani, Carlo, Fraccaro, C., Tarantini, G., Aranzulla, T. C., Musumeci, Giampaolo, Stefanini, G. G., Taramasso, M., Kim, H. -S., Codner, P., Kornowski, R., Pelliccia, F., Vignali, L., Makkar, R. R., Palmerini T., Saia F., Bedogni F., Chieffo A., Porto I. (ORCID:0000-0002-9854-5046), Burzotta F. (ORCID:0000-0002-6569-9401), Trani C. (ORCID:0000-0001-9777-013X), Musumeci G., Ahmad, Y., Oakley, L., Yoon, S., Kaewkes, D., Chakravarty, T., Patel, C., Palmerini, Tullio, Bruno, A. G., Saia, Francesco, Testa, L., Bedogni, Francesco, Chieffo, Alaide, Montorfano, M., Bartorelli, A. L., Porto, Italo, Grube, E., Nickenig, G., Sinning, J. -M., De Carlo, M., Petronio, A. S., Barbanti, M., Tamburino, C., Iadanza, A., Burzotta, Francesco, Trani, Carlo, Fraccaro, C., Tarantini, G., Aranzulla, T. C., Musumeci, Giampaolo, Stefanini, G. G., Taramasso, M., Kim, H. -S., Codner, P., Kornowski, R., Pelliccia, F., Vignali, L., Makkar, R. R., Palmerini T., Saia F., Bedogni F., Chieffo A., Porto I. (ORCID:0000-0002-9854-5046), Burzotta F. (ORCID:0000-0002-6569-9401), Trani C. (ORCID:0000-0001-9777-013X), and Musumeci G.
- Abstract
Background: Coronary obstruction following transcatheter aortic valve replacement (TAVR) is a life-threatening complication. For patients at elevated risk, it is not known how valve choice is influenced by clinical and anatomic factors and how outcomes differ between valve platforms. For patients at high risk of coronary obstruction, we sought to describe the anatomical and clinical characteristics of patients treated with both balloon-expandable (BE) and self-expanding (SE) valves. Methods: This was a multicenter international registry of patients undergoing TAVR who are considered to be at high risk of coronary obstruction and receiving pre-emptive coronary protection. Results: A total of 236 patients were included. Patients receiving SE valves were more likely to undergo valve-in-valve procedures and also had smaller sinuses of Valsalva and valve-to-coronary distance. Three-year cardiac mortality was 21.6% with SE vs 3.7% with BE valves. This was primarily driven by increased rates of definite or probable coronary occlusion, which occurred in 12.1% of patients with SE valves vs 2.1% in patients with BE valves. Conclusions: In patients undergoing TAVR with coronary protection, those treated with SE valves had increased rates of clinical and anatomic features that increase the risk of coronary obstruction. These include an increased frequency of valve-in-valve procedures, smaller sinuses of Valsalva, and smaller valve-to-coronary distances. These patients were observed to have increased cardiac mortality compared with patients treated with BE valves, but this is likely due to their higher risk clinical and anatomic phenotypes rather than as a function of the valve type itself.
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- 2022
14. On the conservation laws for a certain class of nonlinear wave equation via a new conservation theorem
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Al-Dweik, Ahmad Y.
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- 2012
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15. Influence of different stabilizers on the optical and nonlinear optical properties of CdTe nanoparticles
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Abd El-sadek, M.S., Nooralden, Ahmad Y., Moorthy Babu, S., and Palanisamy, P.K.
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- 2011
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16. What are the Predictors that Affect the Excellent Long-term Benefits of Redo Coronary Artery Bypass Grafting?
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Ali, Ayyaz, Ramoutar, Darryl, Ashrafian, Hutan, Abu-Omar, Yasir, Freed, Darren, Sheikh, Ahmad Y., Ali, Ziad, Athanasiou, Thanos, and Wallwork, John
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- 2010
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17. Relation of sex to morbidity and mortality in patients with heart failure and reduced or preserved left ventricular ejection fraction
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Alla, FrancOis, Al-Hindi, Ahmad Y., Lee, Craig R., Schwartz, Todd A., Patterson, J. Herbert, and Adams, Kirkwood F.
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Heart failure -- Patient outcomes ,Cardiac patients -- Patient outcomes ,Mortality ,Health - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ahj.2007.03.016 Byline: Francois Alla (e), Ahmad Y. Al-Hindi (a)(b), Craig R. Lee (c), Todd A. Schwartz (d), J. Herbert Patterson (c), Kirkwood F. Adams (a)(b) Abstract: Previous studies indicate a survival advantage for women over men with chronic heart failure associated with reduced or preserved ejection fraction. Whether women with chronic heart failure are at less risk for hospitalization for worsening heart failure has not been well investigated. Author Affiliation: (a) Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC (b) Department of Radiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC (c) School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC (d) Department of Biostatistics, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC (e) Department of Epidemiology, University Hospital of Nancy, Nancy, France Article History: Received 26 July 2006; Accepted 7 March 2007
- Published
- 2007
18. Enhanced Bellmunt Risk Score for Survival Prediction in Urothelial Carcinoma Treated With Immunotherapy.
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Abuhelwa, Ahmad Y., Bellmunt, Joaquim, Kichenadasse, Ganessan, McKinnon, Ross A., Rowland, Andrew, Sorich, Michael J., and Hopkins, Ashley M.
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CANCER immunotherapy , *TRANSITIONAL cell carcinoma , *IMMUNE checkpoint inhibitors , *C-reactive protein , *OVERALL survival - Abstract
The Bellmunt risk score is a well-recognized prognostic model in urothelial carcinoma. However, its discrimination performance for immune checkpoint inhibitor (ICI) therapy is unclear. The present analysis indicates addition of C-reactive protein (CRP > 30 mg/L) to the Bellmunt model enables more accurate patient discrimination. Introduction: The discrimination performance of Bellmunt risk score for immune checkpoint inhibitor (ICI) therapy is largely unknown. This study aimed to validate and enhance discrimination of the Bellmunt score in patients with urothelial carcinoma treated with ICIs. Patients and Methods: Cox proportional hazard analysis were used to validate overall survival (OS) discrimination performance of the Bellmunt score in patients with urothelial carcinoma treated with atezolizumab in IMvigor210. The c-statistic (c) was used to evaluate the ability of C-reactive protein (CRP), neutrophilto-lymphocyte ratio (NLR), lactate dehydrogenase (LDH), PD-L1 gene expression level on immune cells (PD-L1 ICs), albumin, time from prior chemotherapy, and tumor site count to enhance the Bellmunt score. External validation of an enhanced Bellmunt score utilized the independent atezolizumab arm of IMvigor211. Results: In IMvigor210, Bellmunt score displayed moderate OS discrimination (c = 0.66). Addition of CRP (one point for CRP > 30 mg/L) to the Bellmunt score resulted in greatest improvement in performance (c = 0.70), followed by NLR (c = 0.69). On external validation, CRP-Bellmunt score had superior performance (OS c = 0.67, PFS c = 0.60) than original Bellmunt score (OS c = 0.64, PFS c = 0.59) with 30% of patients reclassified into a higher risk group. Patients with CRP-Bellmunt score of 0, 1, 2, or 3-plus had 1-year OS probabilities of 63%, 44%, 21%, and 15%, respectively. Conclusion: CRP inclusion within the Bellmunt score enhanced the ability to discriminate high risk patients misclassified using the original model. We propose that the CRP-Bellmunt score may enable improved patient stratification in ICI clinical trials and provide more accurate prognostic information for patients with urothelial carcinoma initiating ICIs. [ABSTRACT FROM AUTHOR]
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- 2022
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19. Variations in length of stay of inpatients with COVID-19: A nationwide test of the new model of care under vision 2030 in Saudi Arabia.
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Alharbi, Abdullah A., Alqassim, Ahmad Y., Alharbi, Ahmad A., Gosadi, Ibrahim M., Aqeeli, Abdulwahab A., Muaddi, Mohammed A., Makeen, Anwar M., and Alharbi, Osama A.
- Abstract
The coronavirus disease 2019 (COVID-19) has impacted the Kingdom of Saudi Arabia (KSA) as it has other nations. However, length of stay (LOS), as a healthcare quality indicator, has not been examined across the healthcare regions in the KSA. Therefore, this study aimed to examine factors associated with LOS to better understand the Saudi Health System's performance in response to the COVID-19 pandemic in the newly suggested five Saudi regional business units (BUs). A retrospective study was conducted using Ministry of Health (MOH) data on hospital LOS during the period from March to mid-July 2020. Participants were adult inpatients (18 years or older) with confirmed COVID-19 (n = 1743 patients). The 13 regions of the KSA were united into the defined five regional BUs during the reorganization of the health system. Covariates included demographics such as age and sex, comorbidities, and complications of COVID-19. A multiple linear regression with stepwise forward selection was used to model LOS for other explanatory variables associated with LOS, including demographic, comorbidities, and complications. The mean LOS was 11.85 days which differed significantly across the BUs, ranging from 9.3 days to 13.3 days (p value < 0.001). BUs differed significantly in LOS for transferred patients but not for patients in the intensive care unit (ICU) or those who died in-hospital. The multiple regression analysis revealed that the LOS for inpatients admitted in the Eastern and Southern BUs was significantly shorter than for those in the Central BU. (p value < 0.001). Admission to the ICU was associated with lengthier stays (p value < 0.0001). Factors significantly associated with shorter stays (compared to the reference), were being Saudi, death during admission, and patients referred to another hospital (p value < 0.05). The LOS for patients with COVID-19 differed across the proposed regional healthcare BUs, suggesting regional differences in quality of care under the reorganization of the national health system. Since patient and disease characteristics did not explain these findings, differences in staffing and other resources need to be examined to develop interventions. [ABSTRACT FROM AUTHOR]
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- 2021
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20. Prediction of severe neutropenia and diarrhoea in breast cancer patients treated with abemaciclib.
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Modi, Natansh D., Abuhelwa, Ahmad Y., Badaoui, Sarah, Shaw, Emily, Shankaran, Kiran, McKinnon, Ross A., Rowland, Andrew, Sorich, Michael J., and Hopkins, Ashley M.
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FEBRILE neutropenia ,BREAST cancer ,LEUKOCYTE count ,NEUTROPENIA ,DIARRHEA ,CANCER patients - Abstract
Neutropenia and diarrhoea are common and potentially serious adverse events associated with abemaciclib in advanced breast cancer (ABC), and the risk factors have been minimally explored. The study aimed to develop clinical prediction tools that allow personalized predictions of neutropenia and diarrhoea following abemaciclib initiation. Data was pooled from MONARCH 1, 2 and 3 trials investigating abemaciclib. Cox proportional hazard analysis was used to assess the association between pre-treatment clinicopathological data and grade ≥3 diarrhoea and neutropenia occurring within the first 365 days of abemaciclib use. Older age was associated with increased risk of grade ≥3 diarrhoea [HR [95%CI] for age > 70: 1.72 [1.14–2.58]; P = 0.009]. A clinical prediction tool for abemaciclib induced grade ≥3 neutropenia was optimally defined by race, ECOGPS and white blood cell count. Large discrimination between subgroups was observed; the highest risk subgroup had a 64% probability of grade ≥3 neutropenia within the first 365 days of abemaciclib (150 mg twice daily) + fulvestrant/NSAI, compared to 5% for the lowest risk subgroup. The study identified advanced age as significantly associated with an increased risk of abemaciclib induced grade ≥ 3 diarrhoea. A clinical prediction tool, defined by race, ECOGPS and pre-treatment white blood cell count, was able to discriminate subgroups with significantly different risks of grade ≥3 neutropenia following abemaciclib initiation. The tool may enable improved interpretation of personalized risks and the risk-benefit ratio of abemaciclib. • Neutropenia and diarrhoea are common adverse effects of abemaciclib. • Higher age was associated with abemaciclib induced diarrhoea. • White blood cell count, Race, and performance status were linked with neutropenia. • A prediction tool was developed to provide personalized risks of neutropenia. [ABSTRACT FROM AUTHOR]
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- 2021
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21. Mo1404 INTRAHEPATIC VERSUS EXTRAHEPATIC BILE DUCT ACCESS DURING ENDOSCOPIC ULTRASOUND GUIDED RENDEZVOUS FOR DIFFICULT BILIARY CANNULATION: A SYSTEMATIC REVIEW AND META-ANALYSIS.
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Alsakarneh, Saqr, Jaber, Fouad, Khraisat, Farah A., Madi, Mahmoud Y., Ahmed, Mohamed, Asha, Ahmad Y., Dahiya, Dushyant Singh, Beran, Azizullah, Ghoz, Hassan, and Bilal, Mohammad
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- 2024
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22. Regional differences in COVID-19 ICU admission rates in the Kingdom of Saudi Arabia: A simulation of the new model of care under vision 2030.
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Alharbi, Abdullah A., Alqassim, Ahmad Y., Gosadi, Ibrahim M., Aqeeli, Abdulwahab A., Muaddi, Mohammed A., Makeen, Anwar M., Alhazmi, Abdulaziz H., and Alharbi, Ahmad A.
- Abstract
Saudi Arabia has succeeded in having one of the lowest rates of COVID-19 worldwide due to the government's initiatives in taking swift action to control both the spread and severity of the virus. However, Covid-19 can serve as a test case of the expected response of the new healthcare system under Vision 2030. This study used data from the thirteen present administrative regions of KSA to simulate the variations in ICU admission as a quality indicator in the five business units proposed by a new Model of Care. We determined the rates of ICU admission for patients with confirmed SARS-CoV-2 (COVID-19) from March to mid-July 2020. The final sample included 1743 inpatients with moderate to severe COVID-19. Patient characteristics, including demographics, pre-existing chronic conditions, and COVID-19 complications, were collected. Business units (BUs) were compared with respect to the relative odds of ICU admission by using multiple logistic regression. After keeping patient and clinical characteristics constant, clear BU differences were observed in the relative odds of ICU admission of COVID-19 patients. Inpatient admission to ICU in our total sample was almost 50%. Compared to the Central BU, the Northern and Western BUs showed significantly higher odds of ICU admission while the Eastern & Southern BUs had significantly lower odds. ICU use for COVID-19 patients differed significantly in KSA healthcare BUs, consistent with variations in care for other non-COVID-19-related conditions. These differences cannot be explained by patient or clinical characteristics, suggesting quality-of-care differences. We believe that privatization and the shift to fewer administrative BUs will help lessen or eliminate altogether the present variations in healthcare service provision. [ABSTRACT FROM AUTHOR]
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- 2021
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23. Smoking and immunotherapy efficacy in lung cancer by PDL1 subgroups: An individual participant data meta-analysis of atezolizumab clinical trials: Smoking and immunotherapy efficacy in lung cancer.
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Hopkins, Ashley M., Abuhelwa, Ahmad Y., McKinnon, Ross A., Logan, Jessica M., Kichenadasse, Ganessan, Rowland, Andrew, and Sorich, Michael J.
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TREATMENT of lung tumors , *DRUG efficacy , *SMOKING , *IMMUNOTHERAPY - Published
- 2022
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24. 803 Clinical Outcomes of Patients With Diffuse Coronary Artery Disease Following Physiology-Guided Treatment Strategy: Insights From AJIP Registry
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Warisawa, T., M. Cook, C., Nour, D., P. Howard, J., Rajkumar, C., Seligman, H., Ahmad, Y., Doi, S., Nakajima, A., Nakayama, M., Goto, S., Yamanaka, F., Kikuta, Y., Yakuta, Y., Karube, K., Uetani, T., Shiono, Y., Kawase, Y., Nishina, H., Matsuo, H., Escaned, J., J. Akashi, Y., and E. Davies, J.
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- 2020
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25. A comprehensive micro unmanned aerial vehicle (UAV/Drone) forensic framework.
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Renduchintala, Ankit, Jahan, Farha, Khanna, Raghav, and Javaid, Ahmad Y.
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MICRO air vehicles ,FORENSIC sciences ,GRAPHICAL user interfaces ,CRIME scenes ,ELECTRONIC equipment ,TELEMARKETING - Abstract
In the early 1990s, unmanned aerial vehicles (UAV) were used exclusively in military applications by various developed countries. Now with its ease of availability and affordability in the electronic device market, this aerial vehicular technology has augmented its familiarity in public and has expanded its usage to countries all over the world. However, expanded use of UAVs, colloquially known as drones, is raising understandable security concerns. With the increasing possibility of drones' misuse and their abilities to get close to critical targets, drones are prone to potentially committing crimes and, therefore, investigation of such activities is a much-needed facet. This motivated us to devise a comprehensive drone forensic framework that includes hardware/physical and digital forensics, proficient enough for the post-flight investigation of drone's activity. For hardware/physical forensics, we propose a model for investigating drone components at the crime scene. Additionally, we propose a robust digital drone forensic application with a primary focus on analyzing the essential log parameters of drones through a graphical user interface (GUI) developed using JavaFX 8.0. This application interface would allow users to extract and examine onboard flight information. It also includes a file converter created for easy and effective 3D flight trajectory visualization. We used two popular drones for conducting this research; namely, DJI Phantom 4 and Yuneec Typhoon H. The interface also provides a visual representation of the sensor recordings from which pieces of evidence could be acquired. Our research is intended to offer the forensic science community a powerful approach for investigating drone-related crimes effectively. [ABSTRACT FROM AUTHOR]
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- 2019
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26. Early and late anti nociceptive effects of sucrose on neonatal inflammatory pain in rats: Comparison to a non-steroidal anti-inflammatory drug.
- Author
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Nuseir, Khawla Q., Altarifi, Ahmad Y., Tasslaq, Alaa, Alhusban, Ahmd Y., and Alzoubi, Karem H.
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DRUG side effects , *SUCROSE , *ANTI-inflammatory agents , *EXPERIMENTAL arthritis , *PAIN management , *CHRONIC pain - Abstract
Management of neonatal pain is not only ethical but is also essential. Barriers to pain management in infants include lack of safe and effective medications and fear of adverse effects of conventional pain medications. Sweet solutions given intraorally have been shown to reduce pain behaviors and associated symptoms. Sucrose and other sweet solutions are being increasingly used at the NICUs and immunization clinics. Sucrose for mild invasive procedures is effective and safe for those procedures that need to be repeated multiple times during the day. Only few studies examine the efficacy of sucrose for the management of inflammatory pain during infancy. In this study, Complete Freund's Adjuvant (CFA) was used to induce inflammation in 5-day-old rat pups; CFA also produces inflammation that lasts for more than a day, thus can also be a model for chronic pain. Sucrose or ibuprofen was given to subset of pups shortly after CFA intraplantar injections. Thermal as well as mechanical pain sensitivity was assessed on subsequent days as well as during adolescence and early adulthood. Sucrose and ibuprofen were both effective in preventing hyperalgesia and allodynia produced by CFA. Interestingly, sucrose was even more effective than ibuprofen, and the analgesic effects continued further to adolescence and adult life of the rats. Thus, and according to the results of this study, sucrose seems to be just as effective for inflammatory pain as Ibuprofen. In addition, sucrose protects against later-in-life hypersensitivity consequences to neonatal pain. • Sucrose is antinociceptive in inflammatory pain during infancy. • Sucrose-produced antinociception is superior to ibuprofen. • Sucrose and ibuprofen reversed hyperalgesia and allodynia at infancy. • Sucrose and ibuprofen reversed hyperalgesia and allodynia during adolescence. • Sucrose protective effects extended to early adulthood. [ABSTRACT FROM AUTHOR]
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- 2019
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27. S31. Guillain–Barré syndrome outcome at Cipto Mangunkusumo Hospital Jakarta Indonesia
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Safri, Ahmad Y., Avisenna, Ramdinal, Indrawati, Luh Ari, Octaviana, Fitri, and Hakim, Manfaluthy
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- 2018
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28. Characterizing thiol redox dynamics in the organogenesis stage rat embryo.
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Veltman, K., Ahmad, Y., Harris, C., and Jolliet, O.
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GLUTATHIONE , *DISULFIDES , *MAMMALIAN embryos , *MAMMAL development , *RATS - Abstract
Precise control of the glutathione (GSH): glutathione disulfide (GSSG) balance is vital for the developing embryo, but it is not yet well understood how GSH levels and the GSH redox state are regulated, maintained, and modulated over the course of mammalian embryonic development. In this study, we characterize and connect thiol redox dynamics, protein synthesis, volumetric growth and net cysteine fluxes over the course of early organogenesis (gestational day (GD) 10–GD11.13) in the rat embryo. Our results show that despite a significant exponential growth of conceptal volumes and protein mass, the GSH: GSSG redox balance is remarkably stable during early organogenesis, with distinct redox potentials for the visceral yolk sac (VYS) (− 218 mV) and the embryo proper (EMB) (− 222 mV). The yolk sac was found to play a key role in maintaining GSH levels and the GSH: GSSG redox balance in the developing embryo. Based on an overall cysteine (Cys) mass-balance, we show that until GD10.6, yolk sac supply of Cys, the rate-limiting precursor for GSH synthesis, is sufficient to sustain embryonic demands for its GSH synthesis and protein synthesis needs. After GD10.6, the EMB maintains the amino acid intake flux, resulting in a significant depletion of most thiols in the amniotic fluid and the yolk sac fluid. Cysteine, was found to be predominantly used for de novo protein synthesis in the developing embryo (approximately 90% of total Cys). Protein synthesis (rates) should thus be included in any quantitative assessment of GSH redox dynamics in the developing embryo. Our time-course dataset of thiol dynamics, developed exponential relationships for protein synthesis and volumetric growth, and yolk sac surface area-mediated protein influx, provide important quantitative insights in GSH redox dynamics during embryonic development and are a prerequisite to further develop quantitative ‘systems biology’ models for GSH metabolism in the developing embryo. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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29. Food, gastrointestinal pH, and models of oral drug absorption.
- Author
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Abuhelwa, Ahmad Y., Williams, Desmond B., Upton, Richard N., and Foster, David J.R.
- Subjects
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FOOD , *ORAL medication , *ABSORPTION , *BIOAVAILABILITY , *GASTROINTESTINAL diseases - Abstract
This article reviews the major physiological and physicochemical principles of the effect of food and gastrointestinal (GI) pH on the absorption and bioavailability of oral drugs, and the various absorption models that are used to describe/predict oral drug absorption. The rate and extent of oral drug absorption is determined by a complex interaction between a drug’s physicochemical properties, GI physiologic factors, and the nature of the formulation administered. GI pH is an important factor that can markedly affect oral drug absorption and bioavailability as it may have significant influence on drug dissolution & solubility, drug release, drug stability, and intestinal permeability. Different regions of the GI tract have different drug absorptive properties. Thus, the transit time in each GI region and its variability between subjects may contribute to the variability in the rate and/or extent of drug absorption. Food-drug interactions can result in delayed, decreased, increased, and sometimes un-altered drug absorption. Food effects on oral absorption can be achieved by direct and indirect mechanisms. Various models have been proposed to describe oral absorption ranging from empirical models to the more sophisticated “mechanism-based” models. Through understanding of the physicochemical and physiological rate-limiting factors affecting oral absorption, modellers can implement simplified population-based modelling approaches that are less complex than whole-body physiologically-based models but still capture the essential elements in a physiological way and hence will be more suited for population modelling of large clinical data sets. It will also help formulation scientists to better predict formulation performance and to develop formulations that maximize oral bioavailability. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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30. Repair of Enlarging Left Ventricular Pseudoaneurysm Two Months After Coronary Artery Bypass Grafting.
- Author
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Weber, Daniel J., Sheikh, Ahmad Y., Cain, Brian S., LaBourene, Jay I., and Melikian, Vicken
- Abstract
Enlarging left ventricular pseudoaneurysms are a rare complication (especially after surgical revascularization) and require tailored surgical decision making and techniques for repair. We present a challenging patient with a rapidly enlarging left ventricular pseudoaneurysm 4 weeks after coronary bypass. The repair was approached through a left thoracotomy using circulatory arrest with selective antegrade cerebral perfusion. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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31. Abstract No. 523 Geospatial and Socioeconomic Disparities in Access to Interventional Radiology Care in the United States.
- Author
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Ahmad, Y., Asad, N., Nasir, R., and Ahmed, O.
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- 2023
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32. A point symmetry based method for transforming ODEs with three-dimensional symmetry algebras to their canonical forms.
- Author
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Azad, H., Al-Dweik, Ahmad Y., Mahomed, F.M., and Mustafa, M.T.
- Subjects
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MATHEMATICAL symmetry , *ORDINARY differential equations , *ALGEBRA , *CANONICAL correlation (Statistics) , *MATHEMATICAL forms - Abstract
We provide an algorithmic approach to the construction of point transformations for scalar ordinary differential equations that admit three-dimensional symmetry algebras which lead to their respective canonical forms. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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33. Creation and Global Deployment of a Mobile, Application-Based Cognitive Simulator for Cardiac Surgical Procedures.
- Author
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Brewer, Zachary E., Ogden, William David, Fann, James I., Burdon, Thomas A., and Sheikh, Ahmad Y.
- Abstract
Several modern learning frameworks (eg, cognitive apprenticeship, anchored instruction, and situated cognition) posit the utility of nontraditional methods for effective experiential learning. Thus, development of novel educational tools emphasizing the cognitive framework of operative sequences may be of benefit to surgical trainees. We propose the development and global deployment of an effective, mobile cognitive cardiac surgical simulator. In methods, 16 preclinical medical students were assessed. Overall, 4 separate surgical modules (sternotomy, cannulation, decannulation, and sternal closure) were created utilizing the Touch Surgery (London, UK) platform. Modules were made available to download free of charge for use on mobile devices. Usage data were collected over a 6-month period. Educational efficacy of the modules was evaluated by randomizing a cohort of medical students to either module usage or traditional, reading-based self-study, followed by a multiple-choice learning assessment tool. In results, downloads of the simulator achieved global penetrance, with highest usage in the USA, Brazil, Italy, UK, and India. Overall, 5368 unique users conducted a total of 1971 hours of simulation. Evaluation of the medical student cohort revealed significantly higher assessment scores in those randomized to module use versus traditional reading (75% ± 9% vs 61% ± 7%, respectively; P < 0.05). In conclusion, this study represents the first effort to create a mobile, interactive cognitive simulator for cardiac surgery. Simulators of this type may be effective for the training and assessment of surgical students. We investigated whether an interactive, mobile-computing-based cognitive task simulator for cardiac surgery could be developed, deployed, and validated. Our findings suggest that such simulators may be a useful learning tool. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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34. ADVAN-style analytical solutions for common pharmacokinetic models.
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Abuhelwa, Ahmad Y., Foster, David J.R., and Upton, Richard N.
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PHARMACOKINETICS , *DRUG dosage , *INTRAVENOUS therapy , *LAPLACE transformation , *ANALYTICAL solutions , *OPEN source software - Abstract
Introduction The analytical solutions to compartmental pharmacokinetic models are well known, but have not been presented in a form that easily allows for complex dosing regimen and changes in covariate/parameter values that may occur at discrete times within and/or between dosing intervals. Methods Laplace transforms were used to derive ADVAN-style analytical solutions for 1, 2, and 3 compartment pharmacokinetic linear models of intravenous and first-order absorption drug administration. The equations calculate the change in drug amounts in each compartment of the model over a time interval ( t ; t = t 2 − t 1 ) accounting for any dose or covariate events acting in the time interval. The equations were coded in the R language and used to simulate the time-course of drug amounts in each compartment of the systems. The equations were validated against commercial software [NONMEM (Beal, Sheiner, Boeckmann, & Bauer, 2009)] output to assess their capability to handle both complex dosage regimens and the effect of changes in covariate/parameter values that may occur at discrete times within or between dosing intervals. Results For all tested pharmacokinetic models, the time-course of drug amounts using the ADVAN-style analytical solutions were identical to NONMEM outputs to at least four significant figures, confirming the validity of the presented equations. Discussion To our knowledge, this paper presents the ADVAN-style equations for common pharmacokinetic models in the literature for the first time. The presented ADVAN-style equations overcome obstacles to implementing the classical analytical solutions in software, and have speed advantages over solutions using differential equation solvers. The equations presented in this paper fill a gap in the pharmacokinetic literature, and it is expected that these equations will facilitate the investigation of useful open-source software for modelling pharmacokinetic data. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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35. Evaluation of Effects of Pharmaceutical Processing on Structural Disorders of Active Pharmaceutical Ingredient Crystals Using Nanoindentation and High-Resolution Total Scattering Pair Distribution Function Analysis.
- Author
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Chen, Shuang, Sheikh, Ahmad Y., and Ho, Raimundo
- Subjects
- *
NANOINDENTATION tests , *PHARMACEUTICAL industry , *LIGHT scattering , *HARDNESS , *DISSOLUTION (Chemistry) , *CRYSTAL structure - Abstract
Pharmaceutical unit operations such as milling and compaction can often generate disordered regions in crystals of active pharmaceutical ingredients ( APIs). This may lead to changes in a number of important pharmaceutical properties including dissolution, stability, hygroscopicity, and so on. It is therefore important for pharmaceutical industry to evaluate the effects of pharmaceutical processing on API structural orders, and to investigate and develop analytical tools that are capable of accurately detecting and assessing subtle process-induced structural disorders in pharmaceutical crystals. In this study, nanoindentation was first used to determine the intrinsic mechanical properties including hardness and Young's modulus of two API crystals, compounds 1 and 2. These crystals of different mechanical properties were then milled and compacted under various conditions. The resulting structural disorders in these crystals were subsequently evaluated using synchrotron-based high-resolution total scattering pair distribution function ( TS- PDF) analysis. Furthermore, principal component analysis was applied to the PDF data to assess the relative extents of disorders in the API crystals, which showed a good correlation with the process conditions. The study demonstrates that high-resolution TS- PDF analysis coupled with nanoindentation measurement is a valuable and effective tool for detecting and assessing process-induced subtle structural disorders in API crystals. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3879-3890, 2014 [ABSTRACT FROM AUTHOR]
- Published
- 2014
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36. Individual differences in field independence influence the ability to determine accurate needle angles.
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Sheikh, Ahmad Y., Keehner, Madeleine, Walker, Audrey, Chang, Paul A., Burdon, Thomas A., and Fann, James I.
- Abstract
Objective "Field dependence" is used in cognitive psychology to describe an individual's tendency to be visually distracted by the surrounding environment. Notwithstanding the role of field dependence in contexts in which spatial judgment is important, such as piloting an aircraft, to date, studies linking field dependence to surgical skills have been limited. We evaluated whether field dependence correlates with an ability to anticipate appropriate needle angles in a simulated setting. Methods Trainees underwent field dependence testing and then participated in a surgical skills exercise. Correlations between field dependence and surgical skill were computed. Specifically, cardiothoracic surgery residents (n = 11) took a battery of cognitive examinations to assess general reasoning and visuospatial judgment. Two written tests, the Rod and Frame test and the Judgment of Line Orientation test, measured the degree of field dependence. The subjects then underwent surgical skills testing. Using a standard needle driver, the participants placed curved needles into a cylindrical silicone mitral valve model with 10 premarked needle entry and exit sites. The components assessed included the ability to load a needle on driver at the appropriate angle. Results The test results showed a parametric distribution, with internal cognitive testing controls demonstrating valid testing techniques and methods. Performance on the cognitive tests measuring spatial judgment and field dependence correlated significantly with skill at determining the appropriate needle angle load in an inverse fashion (Judgment of Line Orientation test, r = 0.61, P < .05; Rod and Frame test, r = -0.52, P = .05), suggesting that residents who were not distracted by surrounding objects performed better. Performance on the cognitive examinations did not correlate with resident training level. Conclusions Although our study was of a small cohort, the findings suggest that individuals described as field independent (not easily distracted by external visual cues) might possess improved ability to determine appropriate needle angle loads compared with field-dependent individuals. Additional studies examining the role field dependence might play in the acquisition and execution of surgical tasks are warranted. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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37. Resource use trends in extracorporeal membrane oxygenation in adults: An analysis of the Nationwide Inpatient Sample 1998-2009.
- Author
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Maxwell, Bryan G., Powers, Andrew J., Sheikh, Ahmad Y., Lee, Peter H. U., Lobato, Robert L., and Wong, Jim K.
- Abstract
Objective The study objective was to determine whether significant trends over time have occurred in resource use associated with the use of extracorporeal membrane oxygenation in critically ill adults. Methods All adult admissions involving extracorporeal membrane oxygenation were examined by using the Nationwide Inpatient Sample database (years 1998-2009). Trends in volume, outcome, and resource use (including hospital charges, length of stay, and charges per day) were analyzed. Results An estimated total of 8753 admissions involved extracorporeal membrane oxygenation over the study period. Overall length of stay was 18.3 ± 1.3 days. Total hospital charges averaged $344,009 ± $30,707 per admission, with average charges per day of $40,588 ± $3099. Cumulative national charges for extracorporeal membrane oxygenation admissions increased significantly from $109.0 million in 1998 to $764.7 million in 2009 (P = .0016). Charges per patient and length of stay also increased significantly (P = .0032 and .0321, respectively). The increasing trend in the number of extracorporeal membrane oxygenation admissions during the study period was not statistically significant (P = .19). The post-cardiotomy group had more favorable outcomes and lower resource use. A shift was observed in the relative case-mix of extracorporeal membrane oxygenation admissions over the study period, with a relative decrease in the post-cardiotomy group and increases in the cardiogenic shock, respiratory failure, and lung transplant groups. Conclusions These results suggest that dramatic increases in resource use associated with extracorporeal membrane oxygenation are not solely the result of increased volume, but in part are due to a shift toward extracorporeal membrane oxygenation use in patient groups (other than in the post-cardiotomy setting) with greater resource use and worse outcomes. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
38. A Novel, Catheter-Based Approach to Left Ventricular Assist Device Deactivation After Myocardial Recovery.
- Author
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Zeigler, Sanford M., Sheikh, Ahmad Y., Lee, Peter H. U., Desai, Jay, Banerjee, Dipanjan, Oyer, Philip, Dake, Michael D., and Ha, Richard V.
- Abstract
We describe a case of catheter-based embolization and deactivation of a left ventricular assist device using an Amplatzer plug for a patient demonstrating myocardial recovery after diagnosis of nonischemic cardiomyopathy. This procedure can provide a minimally invasive, low morbidity solution for patients wishing to be separated from left ventricular assist device support who want to avoid invasive surgery for device removal. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
39. Implant-abutment interface: A comparison of the ultimate force to failure among narrow-diameter implant systems.
- Author
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Imam, Ahmad Y., Moshaverinia, Alireza, and McGlumphy, Edwin A.
- Abstract
Statement of problem Limited available alveolar ridge bone and space deficiencies are some of the challenging scenarios that have led many dental implant manufacturers to develop narrow-diameter implants of various designs. Clinicians may have concerns about the durability and function of the narrow-diameter implants. Purpose The purpose of this study was to explore and compare the ultimate failure resistance of the smallest diameter of the 2-stage type implant provided by 5 commonly used dental implant systems. Material and methods Thirty implants, Astra OsseoSpeed 3.0 mm and 3.5 mm, Straumann Bone Level 3.3 mm, Zimmer Tapered Screw-Vent 3.7 mm, Full Osseotite Certain 3.25 mm, and NobelSpeedy Replace 3.5 mm, 5 of each type, were tested in this study. A rigid clamp was used to hold the implants at a 30-degree angle to a static load vector. The load continued until the specimen broke or obviously deformed. Peak loads were recorded at that point for all the studied implant systems. Student t test and 1-way ANOVA were used to compare the mean peak load values (α=.05). Results The mean fracture/deformation peak load values were 367.20 N ±98.05 for Astra OsseoSpeed 3.0 mm; 568.80 N ±85.24 for Astra OsseoSpeed 3.5 mm; 679.00 N ±81.09 for Full Osseotite Certain 3.25 mm; 553.4 N ±56.96 for NobelSpeedy Replace 3.5 mm; 802.80 N ±134.50 for Zimmer Tapered Screw-Vent 3.7 mm; and 576.20 N ±71.45 for Straumann Bone Level 3.3 mm. Generally, a higher load was required to cause failure in implants with larger diameters than in narrower-diameter implants, and more force was necessary to cause failure in Ti6Al4V alloy implants than in commercially pure titanium implants. Conclusions With regard to implant diameter and ultimate failure strength, Osseotite Certain 3.25 mm was considered to be more advantageous in comparison with the other implants tested. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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40. Abstract No. 151 Inferior vena cava filter litigation review: an analysis of medicolegal cases pertaining to IVC filters.
- Author
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Ahmad, Y., Funaki, B., Jilani, S., and Ahmed, O.
- Published
- 2022
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41. SALVAGING AND ANGLED IMPLANT ABUTMENT WITH DAMAGED INTERNAL THREADS: A CLINICAL REPORT.
- Author
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Imam, Ahmad Y., Yilmaz, Burak, Özçelik, Tuncer Burak, and McGlumpy, Edwin
- Abstract
This clinical report describes at technique to fit an existing fixed detachable implant-supported prosthesis to zygomatic implant abutment with stripped internal threads. The threads of the abutment were retapped and a wide diameter/wide head retaining screw was used to secure the existing prosthesis on the abutment. Care is needed in the retrieval of broken screws so as not to damage the internal threads of the implants, which might lead to irreversible complications. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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42. Surgical reconstruction of peripheral pulmonary artery stenosis in Williams and Alagille syndromes.
- Author
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Monge, Michael C., Mainwaring, Richard D., Sheikh, Ahmad Y., Punn, Rajesh, Reddy, V. Mohan, and Hanley, Frank L.
- Subjects
PULMONARY artery abnormalities ,CONGENITAL heart disease ,ARTERIAL stenosis ,ANGIOGRAPHY ,CARDIAC surgery ,REOPERATION ,HOMOGRAFTS ,TRANSPLANTATION of organs, tissues, etc. - Abstract
Objectives: Peripheral pulmonary artery stenosis is a rare congenital heart defect frequently found in association with Williams and Alagille syndromes. Controversy exists regarding the optimal treatment of peripheral pulmonary artery stenosis, with most centers favoring catheter-based interventions. In contrast, we have preferentially used surgical reconstruction of peripheral pulmonary artery stenosis. The purpose of the present study was to review our experience with surgical reconstruction of peripheral pulmonary artery stenosis. Methods: We performed a retrospective review of patients who underwent surgical reconstruction of peripheral pulmonary artery stenosis. A total of 16 patients were identified: 7 had Williams syndrome, 6 had Alagille syndrome, and 3 had no identifiable syndrome. Detailed pulmonary angiography was performed in all patients to define stenoses at the main, branch, lobar, and segmental arterial levels. The mean preoperative right ventricular/left ventricular pressure ratio was 0.88 ± 0.07. The surgical approach was a median sternotomy with cardiopulmonary bypass. All peripheral stenoses were augmented with pulmonary artery homograft tissue. The median age at surgery was 14 months, and concomitant procedures were performed in 9 of the 16 patients. Results: There was 1 operative mortality (6%). The mean right ventricular/left ventricular pressure ratio decreased to 0.40 ± 0.04 postoperatively (P < .005), representing a 55% reduction compared with the preoperative values. The patients were followed up for a median of 5 years. No late mortality occurred and reoperation was not required. Conclusions: The data have demonstrate that this comprehensive surgical approach to the treatment of peripheral pulmonary artery stenosis was associated with low early and no late mortality. Surgical reconstruction of the peripheral pulmonary artery stenosis resulted in a significant decrease in right ventricular pressure. We hypothesize that this reduction in right ventricular pressures will confer a long-term survival advantage for this cohort of patients. [Copyright &y& Elsevier]
- Published
- 2013
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43. Generalization of the double reduction theory
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Bokhari, Ashfaque H., Al-Dweik, Ahmad Y., Zaman, F.D., Kara, A.H., and Mahomed, F.M.
- Subjects
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NUMERICAL solutions to partial differential equations , *INVARIANTS (Mathematics) , *DIMENSIONAL analysis , *NONLINEAR theories , *MATHEMATICAL variables , *MATHEMATICAL symmetry , *NUMERICAL solutions to wave equations - Abstract
Abstract: In a recent work Sjöberg (2007, 2008) remarked that generalization of the double reduction theory to partial differential equations of higher dimensions is still an open problem. In this note we have attempted to provide this generalization to find invariant solution for a non linear system of th order partial differential equations with independent and dependent variables provided that the non linear system of partial differential equations admits a nontrivial conserved form which has at least one associated symmetry in every reduction. In order to give an application of the procedure we apply it to the nonlinear (2+1) wave equation for arbitrary function and . [ABSTRACT FROM AUTHOR]
- Published
- 2010
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44. Conservation laws of a nonlinear wave equation
- Author
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Bokhari, Ashfaque H., Al-Dweik, Ahmad Y., Mahomed, F.M., and Zaman, F.D.
- Subjects
- *
NONLINEAR wave equations , *CONSERVATION laws (Mathematics) , *VARIATIONAL principles , *LAGRANGE equations , *MATHEMATICAL formulas , *MODULES (Algebra) , *MATHEMATICAL symmetry - Abstract
Abstract: Conservation laws of the nonlinear wave equation involving an arbitrary function of the dependent variable, are obtained. This equation is not derivable from a variational principle. By writing the equation, which admits a partial Lagrangian, in the partial Euler–Lagrange form, partial Noether operators associated with the partial Lagrangian are obtained for all possible cases of the arbitrary function. Partial Noether operators are used via a formula in the construction of the conservation laws of the wave equation. If is an arbitrary function, we show that there is a finite number of conservation laws for and an infinite number of conservation laws for . None of the partial Noether operators is a Lie point symmetry of the equation. If is constant, where all of the partial Noether operators are point symmetries of the equation, there is also an infinite number of conservation laws. [Copyright &y& Elsevier]
- Published
- 2010
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45. A Rare Case of Plastic Bronchitis in an Adult Patient After Cardiopulmonary Bypass.
- Author
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Sheikh, Ahmad Y., Ahmadi-Kashani, Mastaneh, Mohindra, Vibha, Friedenberg, Allison, Pramanik, Sharmila B., and Ogden, William D.
- Abstract
Plastic bronchitis is a rare life-threatening complication observed after cardiopulmonary bypass (CPB). We describe a case of a 54-year-old man in whom a fulminant case of plastic bronchitis developed after coronary artery bypass grafting (CABG) and mitral valve repair. A brief review of the literature is also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
46. A novel method to generate key-dependent s-boxes with identical algebraic properties.
- Author
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Al-Dweik, Ahmad Y., Hussain, Iqtadar, Saleh, Moutaz, and Mustafa, M.T.
- Subjects
- *
CRYPTOSYSTEMS , *BLOCK ciphers , *BOOLEAN functions , *PERMUTATIONS , *BIJECTIONS - Abstract
The s-box plays the vital role of creating confusion between the ciphertext and secret key in any cryptosystem, and is the only nonlinear component in many block ciphers. Dynamic s-boxes, as compared to static, improve entropy of the system, hence leading to better resistance against linear and differential attacks. It was shown in Easttom (2018) that while incorporating dynamic s-boxes in cryptosystems is sufficiently secure, they do not keep non-linearity invariant. This work provides an algorithmic scheme to generate key-dependent dynamic n × n clone s-boxes having the same algebraic properties namely bijection, nonlinearity, the strict avalanche criterion (SAC), the output bits independence criterion (BIC) as of the initial seed s-box. The method is based on group action of symmetric group S n and a subgroup S 2 n respectively on columns and rows of Boolean functions (G F (2 n) → G F (2)) of s-box. Invariance of the bijection, nonlinearity, SAC, and BIC for the generated clone copies is proved. As illustration, examples are provided for n = 8 and n = 4 along with comparison of the algebraic properties of the clone and initial seed s-box. The proposed method is an extension of Hussain et al. (2012); Hussain et al. (2012); Hussain et al. (2018); Anees and Chen (2020) which involved group action of S 8 only on columns of Boolean functions (G F (2 8) → G F (2) ) of s-box. For n = 4 , we have used an initial 4 × 4 s-box constructed by Carlisle Adams and Stafford Tavares (Adams and Tavares, 1990) to generated (4 !) 2 clone copies. For n = 8 , it can be seen (Hussain et al. (2012); Hussain et al. (2012); Hussain et al. (2018); Anees and Chen (2020)) that the number of clone copies that can be constructed by permuting the columns is 8 !. For each column permutation, the proposed method enables to generate 8 ! clone copies by permuting the rows. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. Propensity analysis of survival after subcoronary or root replacement techniques for homograft aortic valve replacement.
- Author
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Ali, Ayyaz, Abu-Omar, Yasir, Patel, Amit, Sheikh, Ahmad Y., Ali, Ziad, Saeed, Amber, Akhtar, Asim, Athanasiou, Thanos, and Pepper, John
- Subjects
AORTIC valve surgery ,OPERATIVE surgery ,HOMOGRAFTS ,CONFIDENCE intervals ,LOGISTIC regression analysis ,HEALTH outcome assessment ,HEMODYNAMICS - Abstract
Objective: Homograft aortic valve replacement is associated with excellent clinical and hemodynamic outcomes. Valves are implanted predominantly by using 2 techniques: the freehand subcoronary technique or as an aortic root replacement. Our aim was to identify any difference in survival, durability, and clinical performance. Methods: Demographic, operative, and clinical data were obtained retrospectively through case-note review. All operations were performed by a single surgeon. Propensity score–adjusted analysis was used by developing a nonparsimonious logistic regression model for implantation with subcoronary versus root replacement. Actuarial survival and freedom from valve-related events were compared with Kaplan–Meier curves and multivariable proportional hazard Cox regression. Results: Between January 1, 1991, and January 1, 2001, 215 patients underwent aortic valve replacement with a homograft. The subcoronary technique was used in 131 (61%) patients. Eighty-four (39%) patients underwent free-standing aortic root replacement. After propensity risk adjustment, the subcoronary implantation technique was associated with a decreased risk of 30-day death (adjusted odds ratio, 0.18; 95% confidence interval, 0.06–0.34; P = .03). Technique of insertion was not an independent predictor of overall mortality during follow-up after adjustment (propensity adjusted hazard ratio, 0.35; 95% confidence interval, 0.09–1.41; P = .18). There were no significant differences in 1- and 5-year actuarial survival, freedom from structural valve disease, endocarditis, or reoperation. Conclusions: Both the subcoronary and root replacement techniques for homograft aortic valve replacement are associated with excellent midterm survival and clinical performance. Root replacement was associated with an increased risk of perioperative death after adjustment for covariates by using propensity analysis. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
48. Multimodal evaluation of in vivo magnetic resonance imaging of myocardial restoration by mouse embryonic stem cells.
- Author
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Hendry, Stephen L., van der Bogt, Koen E.A., Sheikh, Ahmad Y., Arai, Takayasu, Dylla, Scott J., Drukker, Micha, McConnell, Michael V., Kutschka, Ingo, Hoyt, Grant, Cao, Feng, Weissman, Irving L., Connolly, Andrew J., Pelletier, Marc P., Wu, Joseph C., Robbins, Robert C., and Yang, Phillip C.
- Subjects
MAGNETIC resonance imaging ,CARDIOMYOPATHIES ,EMBRYONIC stem cells ,MYOCARDIAL infarction ,LABORATORY mice ,FIBROBLASTS ,BIOLUMINESCENCE - Abstract
Objective: Mouse embryonic stem cells have demonstrated potential to restore infarcted myocardium after acute myocardial infarction. Although the underlying mechanism remains controversial, magnetic resonance imaging has provided reliable in vivo assessment of functional recovery after cellular transplants. Multimodal comparison of the restorative effects of mouse embryonic stem cells and mouse embryonic fibroblasts was performed to validate magnetic resonance imaging data and provide mechanistic insight. Methods: SCID-beige mice (n = 55) underwent coronary artery ligation followed by injection of 2.5 × 10
5 mouse embryonic stem cells, 2.5 × 105 mouse embryonic fibroblasts, or normal saline solution. In vivo magnetic resonance imaging of myocardial restoration by mouse embryonic stem cells was evaluated by (1) in vivo pressure–volume loops, (2) in vivo bioluminescence imaging, and (3) ex vivo TaqMan (Roche Molecular Diagnostics, Pleasanton, Calif) polymerase chain reaction and immunohistologic examination. Results: In vivo magnetic resonance imaging demonstrated significant improvement in left ventricular ejection fraction at 1 week in the mouse embryonic stem cell group. This finding was validated with (1) pressure–volume loop analysis demonstrating significantly improved systolic and diastolic functions, (2) bioluminescence imaging and polymerase chain reaction showing superior posttransplant survival of mouse embryonic stem cells, (3) immunohistologic identification of cardiac phenotype within engrafted mouse embryonic stem cells, and (4) polymerase chain reaction measuring increased expressions of angiogenic and antiapoptotic genes and decreased expressions of antifibrotic genes. Conclusion: This study validates in vivo magnetic resonance imaging as an effective means of evaluating the restorative potential of mouse embryonic stem cells. [Copyright &y& Elsevier]- Published
- 2008
- Full Text
- View/download PDF
49. The applicability of sustainable city paradigm to the city of Jerusalem: Criteria and indicators of efficiency.
- Author
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Jarrar, Ola M. and Al-Zoabi, Ahmad Y.
- Subjects
CITIES & towns ,URBAN beautification ,MUNICIPAL government - Abstract
Abstract: Making the world''s villages, towns and cities environmentally, economically and socially sustainable is humanity''s most urgent challenge for the 21st century. This issue has been the focus of many researchers and several studies have been carried out in order to find the closest city form to the ethos of sustainability. Efficiency is one of the main key issues closely related to the sustainable city agenda. Since the concept of sustainable city is highly contextual, this study is concerned with the investigation of the applicability of sustainable city paradigm, in terms of efficiency, to the old city of Jerusalem. Investigation is limited to one major theoretical area, city form; and two minor theoretical areas, street system and land use. In order to carry out the investigation, the study used different methods (multi-method approach) consisting of content analysis and field survey, thus, incorporating the triangulation method in data analysis. The use of different methods was inspired by the very nature of the data collected, and the local context of Jerusalem. Also, the adoption of different methods compensated for the limited sources of data and provided strength for each method. The findings provide evidence that the parameter ‘efficiency’ of the sustainable city paradigm is applicable to the old city of Jerusalem with respect to the city''s form and street system, but this is not the case for land use. The criteria and indicators that were not applicable identified a number of problems in the functioning of the city. The paradigm characterized is not a healing recipe or a blueprint. Rather, it is a flexible framework or a vision out of many others and, thus, disputable. This study provides an approach, out of many others, to investigate the applicability of the sustainable city paradigm on Arabic–Islamic cities in general and the old city of Jerusalem in particular. This approach provides a flexible framework for officials and planners to work through and vision each city''s own version of sustainability. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
50. Agglomerative crystallization of ABT-510 in a partially miscible solvent system.
- Author
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Sheikh, Ahmad Y., Pal, Agnes, Viswanath, Shekhar, and Tolle, John C.
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AGGLOMERATION (Materials) , *CRYSTALLIZATION , *WETTING agents , *PHARMACEUTICAL industry - Abstract
A modification of wet agglomeration technique is developed and demonstrated by agglomerative crystallization process for a nonapeptide (ABT-510) to improve processing of needle like crystals. Our procedure involves exploiting partial miscibility of the crystallization solvent system for in situ generation of a wetting agent with suitable agglomerative properties. Experiences with ABT-510 show that a relatively small fraction of phase separation (1–5%) is needed to create enough wetting agent for effective agglomeration. Manipulations in the properties and quantity of the wetting agent easily achieved by modifying process trajectories in the solvent space lead to significant variations in agglomerative particle shapes. An optimal process trajectory is established by thorough evaluation of solid–liquid equilibria, liquid–liquid equilibria, properties of the wetting agent and agglomerative particle shape. Optimum antisolvent addition profile is also established and the process scaled up using suitable process analytical tools (PAT) to monitor for consistent performance. This optimally designed agglomerative crystallization process consistently lead to agglomeration of the particles just inside the biphasic solvent region. Extremely rapid crystal form conversion to the desired crystalline form is also observed in the vicinity of the biphasic solvent region, probably as a consequence of density fluctuations generated by the onset of solvent immiscibility. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1202–1212, 2008 [ABSTRACT FROM AUTHOR]
- Published
- 2008
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