108 results on '"Ahmed, Kamran"'
Search Results
2. Controversies in neuro-oncology: Focal proton versus photon radiation therapy for adult brain tumors
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Eekers, Danielle B P, Zegers, Catharina M L, Ahmed, Kamran A, Amelio, Dante, Gupta, Tejpal, Harrabi, Semi Ben, Kazda, Tomas, Scartoni, Daniele, Seidel, Clemens, Shih, Helen A, and Minniti, Giuseppe
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Radiation therapy (RT) plays a fundamental role in the treatment of malignant and benign brain tumors. Current state-of-the-art photon- and proton-based RT combines more conformal dose distribution of target volumes and accurate dose delivery while limiting the adverse radiation effects. PubMed was systematically searched from from 2000 to October 2023 to identify studies reporting outcomes related to treatment of central nervous system (CNS)/skull base tumors with PT in adults. Several studies have demonstrated that proton therapy (PT) provides a reduced dose to healthy brain parenchyma compared with photon-based (xRT) radiation techniques. However, whether dosimetric advantages translate into superior clinical outcomes for different adult brain tumors remains an open question. This review aims at critically reviewing the recent studies on PT in adult patients with brain tumors, including glioma, meningiomas, and chordomas, to explore its potential benefits compared with xRT.
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- 2024
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3. Radiation Therapy Followed by Intrathecal Trastuzumab-Pertuzumab for ERBB2-Positive Breast Leptomeningeal Disease: A Phase 1 Nonrandomized Controlled Trial
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Ahmed, Kamran A., Kumthekar, Priya U., Pina, Yolanda, Kim, Youngchul, Vogelbaum, Michael A., Han, Hyo S., and Forsyth, Peter A.
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- 2024
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4. Digital health and inpatient palliative care: a cohort-controlled study
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Singh, Baldev Malkit, Kumari-Dewat, Nisha, Ryder, Adam, Parry, Emma, Klaire, Vijay, Matthews, Dawn, Bennion, Gemma, Jennens, Hannah, Ritzenthaler, Benoit M E, Rayner, Sophie, Shears, Jean, Ahmed, Kamran, Sidhu, Mona, Viswanath, Ananth, and Warren, Kate
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ObjectivesEnd of life has unacceptable levels of hospital admission and death. We aimed to determine the association of a novel digital specific system (Proactive Risk-Based and Data-Driven Assessment of Patients at the End of Life, PRADA) to modify such events.MethodsA cohort-controlled study of those discharged alive, who died within 90 days of discharge, comparing PRADA (n=114) with standard care (n=3730).ResultsAt 90 days, the PRADA group were more likely to die (78.9% vs 46.2%, p<0.001), had a shorter time to death (58±90 vs 178±186 days, p<0.001) but readmission (20.2% vs 37.9%, p<0.001) or death in hospital (4.4% vs 28.9%, p<0.001) was lower with reduced risk for a combined 90-day outcome of postdischarge non-elective admission or hospital death (OR 0.45, 95% CI 0.27–0.74, p<0.001). Tightening criteria with 1:1 matching (n=83 vs 83) showed persistent significant findings in PRADA contact with markedly reduced adverse events (OR 0.15, 95% CI 0.02–0.96, p<0.05).ConclusionsBeing seen in hospital by a specialist palliative care team using the PRADA tool was associated with significantly improved postdischarge outcomes pertaining to those destined to die after discharge.
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- 2024
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5. Virtual reality vs. physical models in surgical skills training. An update of the evidence
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Chahal, Baldev, Aydin, Abdullatif, and Ahmed, Kamran
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- 2024
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6. Decision Regret in Patients with Localised Prostate Cancer: A Systematic Review and Meta-analysis
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Fanshawe, Jack B., Wai-Shun Chan, Vinson, Asif, Aqua, Ng, Alexander, Van Hemelrijck, Mieke, Cathcart, Paul, Challacombe, Ben, Brown, Christian, Popert, Rick, Elhage, Oussama, Ahmed, Kamran, Brunckhorst, Oliver, and Dasgupta, Prokar
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A sizeable proportion of men experience decision regret after a localised prostate cancer diagnosis. Monitoring those with increased functional symptoms and improving patient involvement in the decision-making process through education and decision aids may reduce regret.
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- 2023
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7. A systematic review of non-surgical management in Peyronieʼs disease
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Hayat, Sulaiman, Brunckhorst, Oliver, Alnajjar, Hussain M, Cakir, Onur Omer, Muneer, Asif, and Ahmed, Kamran
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The efficacy of many non-surgical treatments for Peyronie’s disease is unclear. This systematic review aims to critically assess the currently available options and provide a recommendation for treatment based on this. A systematic literature search utilising the Medline (Pubmed), Embase, global health and Cochrane library databases was conducted up to May 2021. All randomised controlled trials assessing non-surgical treatment modalities for Peyronie’s Disease were included. Individual study risk of bias was evaluated using the Cochrane tool and GRADE was used to assess evidence strength. Outcome measures were the change in penile curvature (degrees), plaque size (volume or size), International Index of Erectile Function score, pain scores and change in penile length. Prospero registration number: CRD42017064618. Amongst the 5549 articles identified, 41 studies (42 reports) were included. Seven different oral treatment options including vitamin E supplementation showed evidence for improving outcomes such as penile curvature and plaque size. Of the intralesional treatments, Collagenase Clostridium Histolyticum showed evidence for improving penile curvature (Range: 16.3–17 degrees, moderate level certainty of evidence). Intralesional Interferon demonstrated some improvement in curvature (Range: 12–13.5 degrees), plaque size (Range: 1.67–2.2 cm2) and pain, whilst intralesional calcium channel blockers such as Verapamil showed variable evidence for changes in the plaque size and pain. Extracorporeal Shockwave Therapy consistently demonstrated evidence for improving penile pain in stable disease, and two mechanical traction devices improved curvature. Iontophoresis, topical medications, and combination therapies did not demonstrate any consistent improvements in outcome measures. Intralesional options demonstrate the best potential. Overall, results varied with few high-quality randomised trials present.
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- 2023
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8. Audit Qualification Paragraphs and Audit Report Lag: Evidence from Iran
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Faraji, Omid, MohammadRezaei, Fakhroddin, Yazdifar, Hassan, Ahmed, Kamran, and Najafi Gadikelaei, Yaser
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ABSTRACTWe investigate whether the number and type (the nature and repetitiveness) of audit qualification paragraphs (AQPs) play a role in audit report lag (ARL). We use a unique dataset of listed firms in Iran where the multitude and diversity of AQPs are very high. The results show that ARL is longer for firms with a greater number of AQPs, that there is a significant positive relationship between all AQP types and ARL except for misclassification of accounting numbers in financial statements, and that ARL increases with the number of non-repetitive AQPs. We employed several sensitivity tests, and the results did not change materially. Drawing on prior studies, we have developed two arguments, ‘additional audit procedures’ and ‘auditor-client negotiations’, to explain the role of the number and type of AQPs on ARL. The findings of this study have significant implications for investors, auditors and authority bodies in terms of paying close attention to the number and type of AQPs in their decisions.
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- 2023
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9. Complications and outcomes following injection of foreign material into the male external genitalia for augmentation: a single-centre experience and systematic review
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Pang, Karl H., Randhawa, Karen, Tang, Stanley, Fallara, Giuseppe, Katelaris, Athos, Castiglione, Fabio, Ahmed, Kamran, Blecher, Gideon, Christopher, Nim, Ralph, David J., Muneer, Asif, and Alnajjar, Hussain M.
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Injection of exogenous material into the penis and scrotum has been performed for augmentation purposes. Complications include cosmetic dissatisfaction, penile necrosis and lymphoedema. We report the complications and outcomes from a single centre with an updated systematic review of the literature. A retrospective review of all cases presenting with foreign substance injection into the genitalia, over a 10-year period was performed. Thirty-five patients with a mean (standard deviation (SD); range) age of 36.9 (±9.1; 22–61) years at presentation were included. The mean (SD; range) time between injection and presentation was 7.8 (±5.8; 1 day–20 years) years. The most common injected substance was silicone (n= 16, 45.7%) and liquid paraffin (n= 8, 22.9%). The penile shaft (94.3%) was the most injected site. The most common presentations were cosmetic dissatisfaction (57.1%) and pain and/or swelling (45.7%). Surgery was required in 32 (91.4%) cases. Primary procedures included local excision and primary closure (n= 19, 59.4%), circumcision (n= 5, 15.6%), excision with a split skin graft or a scrotal flap reconstruction (n= 5, 15.6%). Three (8.6%) patients presented with necrosis and required acute debridement. Overall, 18 patients had more than 1 procedure, and 8 patients required 3 or more procedures. A systematic search of the literature identified 887 articles of which 68 studies were included for analysis. The most common substance injected was paraffin (47.7%), followed by silicone (15.8%). The majority of patients (77.9%) presented with pain, swelling or penile deformity. 78.8% of the patients underwent surgical treatment, which included excision and primary closure with or without the use of skin grafts (85.1% of all procedures), the use of flaps (12.3%) and penile amputation (n= 2). Complications of foreign body injection into the male genitalia can be serious resulting in necrosis and autoamputation. Surgical intervention is often required to excise abnormal tissue to manage pain and improve cosmesis.
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- 2023
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10. Busy boards and accounting conservatism – an Australian perspective
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Le, Quyen, Vafaei, Alireza, Ahmed, Kamran, and Kutubi, Shawgat
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Purpose: This paper aims to examine the association between busy directors on corporate boards and accounting conservatism. Design/methodology/approach: The authors use a sample of 500 firms listed on the Australian Security Exchange from 2004 to 2019. The busyness of non-executive directors is proxied by three indicators. For accounting conservatism, the authors use both conditional and unconditional accounting conservatism via asymmetric timeliness of earnings, accrual-based loss recognition, cumulative total accruals and book-to-market ratio. The authors cluster the standard errors at the firm level to compensate for potential residuals’ dependency and heteroscedasticity, in addition to analysing the main models using year and industry fixed effects (Petersen, 2009). Separately, the authors look at the impact of female busy directors on firms’ adoption of conservative accounting methods. Both propensity score matching analyses and Heckman (1979) two-stage approach systematically address endogeneity issues. Findings: The presence of busy directors on boards leads to greater unconditional conservatism and less conditional conservatism. The relationships between busy female directors with both conditional and unconditional conservatism remain consistent with the main findings. Practical implications: This paper provides useful insights for shareholders, regulators and accounting standards setters to better evaluate busy directors’ effectiveness in monitoring firms’ financial reporting quality. Directors and the companies themselves can refer to the authors’ findings to decide the best structure for their boards and committees, considering their specific monitoring requirements. Given that no mandatory restriction has been legislated, improved policies or new ones will ensure that busy directors can effectively fulfil their duties. Originality/value: This research contributes to the broader research theme by examining the influence of directors’ quality on financial reporting conservatism. It also contributes to the ongoing debate in the corporate finance literature regarding the experience and busyness hypotheses of directors with multiple directorships. Additionally, this research adds value to gender diversity research by finding evidence that female busy directors follow the same pattern of reporting conservatism as male busy directors.
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- 2022
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11. Quantitative Changes in Intratumoral Habitats on MRI Correlate With Pathologic Response in Early-stage ER/PR+ HER2− Breast Cancer Treated With Preoperative Stereotactic Ablative Body Radiotherapy
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Jared Weinfurtner, R, Abdalah, Mahmoud, Stringfield, Olya, Ataya, Dana, Williams, Angela, Mooney, Blaise, Rosa, Marilin, Lee, Marie C, Khakpour, Nazanin, Laronga, Christine, Czerniecki, Brian, Diaz, Roberto, Ahmed, Kamran, Washington, Iman, Latifi, Kujtim, Niell, Bethany L, Montejo, Michael, and Raghunand, Natarajan
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- 2022
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12. An empirical investigation of earnings restatements by Australian firms
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Ahmed, Kamran and Goodwin, John
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Banking, finance and accounting industries ,Business - Abstract
To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1467-629X.2006.00196.x Byline: Kamran Ahmed (a), John Goodwin (b) Keywords: Earnings restatements; Value relevance; Firm characteristics Abstract: Abstract From 1970 to 2003, we document earnings restatements for the top 500 Australian firms, examine the characteristics of restating firms, and test whether restatements are value relevant. Of the 195 earnings restatements, 49 per cent decrease prior-period earnings (negative restatements). Negative restatements are relatively larger than positive restatements. We identify three reasons for earnings restatements; namely, accounting policy changes, revision of estimates, and errors and unknown, and they comprise 49, 40 and 11 per cent of the sample, respectively. Restatement firms have higher growth opportunities and are smaller than non-restating firms from the same industry. Restatements are generally negatively associated with market and non-market value. Author Affiliation: (a)School of Business, La Trobe University, Bundoora, 3086, Australia (b)School of Accounting and Law, RMIT University, Melbourne, 3000, Australia Article History: Received 3 August 2005; accepted 15 March 2006 by Gary Monroe (Deputy Editor). doi: 10.1111/j.1467-629x.2006.00196.x
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- 2007
13. Self-harm in South Asian women: a literature review informed approach to assessment and formulation
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Ahmed, Kamran, Mohan, Rajesh A., and Bhugra, Dinesh
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South Asians -- Psychological aspects ,Women -- Psychological aspects ,Self-destructive behavior -- Social aspects ,Self-destructive behavior -- Care and treatment ,Psychology and mental health - Abstract
The rates of self--harm among South Asian women in the United Kingdom are much higher than among their White counterparts. However, the explanation for this is far from clear, and there is a need for more culturally informed assessments for this group. Using literature review we identified cultural factors associated with self--harm in South Asian women. These findings were used to guide the clinical assessment of an Asian woman who had self--harmed using a personal narrative approach. Three independent clinicians analysed the narrative and identified important themes that gave an insight into the problems associated with the incident, arriving at a cultural formulation. Our interview showed that specific cultural factors, such as level of acculturation, cultural conflicts, stigma and interpersonal relationships, were important factors associated with distress and resilience. Literature reviews can help in conducting culturally competent assessments and enable better interventions for this group of patients. The key cultural areas identified are discussed in detail.
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- 2007
14. The value relevance of management's research and development reporting choice: Evidence from Australia
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Ahmed, Kamran and Falk, Haim
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Industrial research -- Analysis ,Research and development ,Banking, finance and accounting industries ,Business - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jaccpubpol.2006.03.002 Byline: Kamran Ahmed (a), Haim Falk (b) Abstract: We examine the value relevance of Australian firms' discretionary R&D accounting policy and the association between this expenditure and the firm's future economic performance. The results indicate that: (1) managerial discretionary accounting practice, capitalizing or expensing R&D expenditure, demonstrates greater value relevance than accounting figures that are the product of mandatory R&D expensing, (2) managerial discretionary capitalized R&D accounting figures demonstrate higher association with market share prices than managerial discretionary expensed expenditure, (3) the strength of the association between R&D accounting figures and the firm's market value is higher for firms that are members of a defined industrial group than for the general population of firms and (4) R&D capitalized expenditure is positively and significantly associated with the firm's future earnings. We also examine the sensitivity of comparative value relevance models to the choice of deflator variables. Our results are robust with respect to such choice. Implications of our findings for accounting rule makers and researchers are also offered. Author Affiliation: (a) Department of Accounting, La Trobe University, Melbourne, Vic 3083, Australia (b) Faculty of Industrial Engineering and Management, Technion, Israel Institute of Technology and Ariel Academic College, Israel
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- 2006
15. Erectile dysfunction in patients with anxiety disorders: a systematic review
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Velurajah, Rajalaxmi, Brunckhorst, Oliver, Waqar, Muhammad, McMullen, Isabel, and Ahmed, Kamran
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Men with anxiety disorders have been identified as high risk of developing erectile dysfunction (ED). The aim of this review is to define the prevalence and severity of ED in the male anxiety disorder population. A literature search of three electronic databases (PubMed, Embase and PsychINFO) and a grey literature registry was conducted. Inclusion criteria were studies that investigated adult males, documented diagnosis of anxiety disorders made by a qualified psychiatrist and use of a validated tool to diagnose ED such as International Index of Erectile Function or ICD-10/DSM-IV. The search yielded 1220 articles and 12 studies were selected. The anxiety disorders investigated were post-traumatic stress disorder, obsessive–compulsive disorder, social phobia/social anxiety disorder and panic disorder. We found that the median [IQR] prevalence of ED was 20.0 [5.1–41.2]% and the median [IQR] International Index of Erectile Function-5 scores were 17.62 [13.88–20.88], indicating a mild to moderate severity. Our review suggests a high prevalence of ED in the anxiety disorder population and ED may be more severe in this cohort, therefore advocating this is an important clinical topic. However, the evidence is limited due to the high heterogeneity between the studies and more research is required in this field.
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- 2022
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16. Procedural virtual reality simulation training for robotic surgery: a randomised controlled trial
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Raison, Nicholas, Harrison, Patrick, Abe, Takashige, Aydin, Abdullatif, Ahmed, Kamran, and Dasgupta, Prokar
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Background: Virtual reality (VR) training is widely used for surgical training, supported by comprehensive, high-quality validation. Technological advances have enabled the development of procedural-based VR training. This study assesses the effectiveness of procedural VR compared to basic skills VR in minimally invasive surgery. Methods: 26 novice participants were randomised to either procedural VR (n= 13) or basic VR simulation (n= 13). Both cohorts completed a structured training programme. Simulator metric data were used to plot learning curves. All participants then performed parts of a robotic radical prostatectomy (RARP) on a fresh frozen cadaver. Performances were compared against a cohort of 9 control participants without any training experience. Performances were video recorded and assessed blindly using GEARS post hoc. Results: Learning curve analysis demonstrated improvements in technical skill for both training modalities although procedural training was associated with greater training effects. Conclusions: This trial has shown that a structured programme of procedural VR simulation is effective for robotic training with technical skills successfully transferred to a clinical task in cadavers. Further work to evaluate the role of procedural-based VR for more advanced surgical skills training is required.
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- 2021
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17. Evaluation of a remote-controlled laparoscopic camera holder for basic laparoscopic skills acquisition: a randomized controlled trial
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Amin, Mohammad S. A., Aydin, Abdullatif, Abbud, Nurhan, Van Cleynenbreugel, Ben, Veneziano, Domenico, Somani, Bhaskar, Gözen, Ali Serdar, Redorta, Juan Palou, Khan, M. Shamim, Dasgupta, Prokar, Makanjuoala, Jonathan, and Ahmed, Kamran
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Background: Unsteady camera movement and poor visualization contribute to a difficult learning curve for laparoscopic surgery. Remote-controlled camera holders (RCHs) aim to mitigate these factors and may be used to overcome barriers to learning. Our aim was to evaluate performance benefits to laparoscopic skill acquisition in novices using a RCH. Methods: Novices were randomized into groups using a human camera assistant (HCA) or the FreeHand v1.0 RCH and trained in the (E-BLUS) curriculum. After completing training, a surgical workload questionnaire (SURG-TLX) was issued to participants. Results: Forty volunteers naïve in laparoscopic skill were randomized into control and intervention groups (n= 20) with intention-to-treat analysis. Each participant received up to 10 training sessions using the E-BLUS curriculum. Competency was reached in the peg transfer task in 5.5 and 7.6 sessions for the ACH and HCA groups, respectively (P= 0.015), and 3.6 and 6.8 sessions for the laparoscopic suturing task (P= 0.0004). No significance differences were achieved in the circle cutting (P= 0.18) or needle guidance tasks (P= 0.32). The RCH group experienced significantly lower workload (P= 0.014) due to lower levels of distraction (P= 0.047). Conclusions: Remote-controlled camera holders have demonstrated the potential to significantly benefit intra-operative performance and surgical experience where camera movement is minimal. Future high-quality studies are needed to evaluate RCHs in clinical practice. Trial registration: ISRCTN 83733979
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- 2021
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18. Depression, anxiety, and suicidality in patients with prostate cancer: a systematic review and meta-analysis of observational studies
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Brunckhorst, Oliver, Hashemi, Safiya, Martin, Anastasia, George, Gincy, Van Hemelrijck, Mieke, Dasgupta, Prokar, Stewart, Robert, and Ahmed, Kamran
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Background: Psychiatric implications of prostate cancer are increasingly recognised, having important effects on oncological and functional outcomes. However, findings for co-occurring depression, anxiety, and suicidality remain variable. Therefore, this review of observational studies aimed to establish best estimates of the prevalence and rates of these outcomes in prostate cancer patients. Methods: A systematic literature search was conducted using MEDLINE, Scopus, PsycInfo, and Cochrane Library databases from inception up to 26 May 2020. Observational studies using validated methods for evaluating prevalences of depression, anxiety and suicidal ideation, or suicide mortality rates post prostate cancer diagnosis were included. Random effect models were used to calculate pooled prevalences of depressive and anxiety symptoms or disorders, and suicidal ideation post diagnosis. Additionally, pooled crude suicide mortality rates per 100,000 person years were calculated. Heterogeneity was explored using a stratified analysis. Results: Of 3537 articles screened, 117 were included. Pooled prevalence for depressive disorders was 5.81% (95% CI 4.36–7.46) in 11 studies, representing 655,149 patients. Significant depressive symptoms were identified in 17.07% (15.14–19.09) across 32,339 patients and 76 studies. In total, 16.86% (14.92–18.89) had significant anxiety symptoms in 56 studies combining 24,526 patients. In 6,173 patients and eight studies, recent suicidal ideation was present in 9.85% (7.31–12.70). Crude suicide mortality rate after diagnosis was 47.1 (39.85–54.96) per 100,000 person years in 12 studies. Significant heterogeneity was seen with potential sources identified through our sensitivity analysis including diagnostic method utilised, study size and location of study. Conclusions: The mental health impact in patients with prostate cancer is significant. Depressive, anxiety, and suicidal symptoms were common. Additionally, a high suicide mortality rate was identified when compared to general population estimates. Screening of patients and integration of physical and mental health care should be evaluated further to improve quality of life and functional outcomes.
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- 2021
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19. Cystine calculi: challenging group of stones
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Ahmed, Kamran, Dasgupta, Prokar, and Khan, Mohammad Shamim
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Aminoaciduria, Renal -- Causes of ,Aminoaciduria, Renal -- Care and treatment ,Kidney stones -- Analysis ,Kidney stones -- Development and progression ,Health - Published
- 2006
20. Development and content validation of a competency-based assessment tool for penile prosthesis surgery
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Wells, Lauren, Ahmed, Kamran, Ralph, David J., and Muneer, Asif
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The aim of this study was to identify potential hazards for the inflatable penile prosthesis (IPP) surgical procedure and from this develop and content validate an IPP intraoperative competency-based assessment tool. A multi-institutional longitudinal prospective observational study was conducted over a 6-month period. Healthcare Failure Mode and Effects Analysis (HFMEA) methodology was used to prospectively risk assess the IPP procedure using a collaborative multidisciplinary team (MDT) approach. International content validation of the developed tool was then undertaken via face-to-face meetings and WebEx seminars. A total of 22 h of observation led to the construction of a detailed process map consisting of 11 stages and 49 sub-stages. HFMEA identified 50 failure modes and 45 failure mode effects, nine failure modes were excluded after analysis leaving 41 key failure modes included in the checklist. The high-risk steps identified were related to corporal dilatation, incorrect sizing of the prosthesis cylinders and incorrect localisation of the superficial inguinal ring for blind reservoir placement. The final content validated IPP assessment tool (PPAT) consisted of 13 processes and 27 sub-processes. We concluded that HFMEA methodology successfully allowed for the identification of key steps within the IPP procedure from which the PPAT was developed. Formal international content validation confirmed that all key procedural steps were included in the PPAT and that completion of all steps would indicate trainee competency in the procedure. Further validation is required before the tool can be used to assess learning curves for the IPP procedure.
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- 2021
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21. Corporate governance and turnaround: Evidence from Australia
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Miglani, Seema, Ahmed, Kamran, and Henry, Darren
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We examine the relationship between ownership and outside director attributes and corporate turnaround outcomes using matched samples of 99 turnaround and 99 non-turnaround listed Australian firms during the 2004–2015 period. Based on agency theory principles, we propose that key shareholder groups (block ownership, director ownership, institutional ownership) and outside directors are related to firm-level turnaround outcomes, and particularly changes in these attributes across decline to turnaround periods. Our results provide evidence that turnaround and non-turnaround firms differ in terms of their ownership and board composition structures, and that changes in director ownership and the degree of board independence are important in determining the likelihood of turnaround success.JEL Classification: G33, G34, M40
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- 2020
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22. A systematic review of simulation-based training tools for technical and non-technical skills in ophthalmology
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Lee, Roxanne, Raison, Nicholas, Lau, Wai Yan, Aydin, Abdullatif, Dasgupta, Prokar, Ahmed, Kamran, and Haldar, Shreya
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To evaluate all simulation models for ophthalmology technical and non-technical skills training and the strength of evidence to support their validity and effectiveness. A systematic search was performed using PubMed and Embase for studies published from inception to 01/07/2019. Studies were analysed according to the training modality: virtual reality; wet-lab; dry-lab models; e-learning. The educational impact of studies was evaluated using Messick’s validity framework and McGaghie’s model of translational outcomes for evaluating effectiveness. One hundred and thirty-one studies were included in this review, with 93 different simulators described. Fifty-three studies were based on virtual reality tools; 47 on wet-lab models; 26 on dry-lab models; 5 on e-learning. Only two studies provided evidence for all five sources of validity assessment. Models with the strongest validity evidence were the Eyesi Surgical, Eyesi Direct Ophthalmoscope and Eye Surgical Skills Assessment Test. Effectiveness ratings for simulator models were mostly limited to level 2 (contained effects) with the exception of the Sophocle vitreoretinal surgery simulator, which was shown at level 3 (downstream effects), and the Eyesi at level 5 (target effects) for cataract surgery. A wide range of models have been described but only the Eyesi has undergone comprehensive investigation. The main weakness is in the poor quality of study design, with a predominance of descriptive reports showing limited validity evidence and few studies investigating the effects of simulation training on patient outcomes. More robust research is needed to enable effective implementation of simulation tools into current training curriculums.
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- 2020
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23. Outcomes and the Role of Primary Histology Following LINAC-based Stereotactic Radiation for Sarcoma Brain Metastases
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Sim, Austin J., Ahmed, Kamran A., Keller, Andrew, Figura, Nicholas B., Oliver, Daniel E., Sarangkasiri, Siriporn, Robinson, Timothy J., Johnstone, Peter A.S., Yu, Hsiang-Hsuan Michael, and Naghavi, Arash O.
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- 2020
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24. Effectiveness of the HoloLens mixed-reality headset in minimally invasive surgery: a simulation-based feasibility study
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Al Janabi, Hasaneen Fathy, Aydin, Abdullatif, Palaneer, Sharanya, Macchione, Nicola, Al-Jabir, Ahmed, Khan, Muhammad Shamim, Dasgupta, Prokar, and Ahmed, Kamran
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Background: The advent of Virtual Reality technologies presents new opportunities for enhancing current surgical practice. Studies suggest that current techniques in endoscopic surgery are prone to disturbance of a surgeon’s visual-motor axis, influencing performance, ergonomics and iatrogenic injury rates. The Microsoft
® HoloLens is a novel head-mounted display that has not been explored within surgical innovation research. This study aims to evaluate the HoloLens as a potential alternative to conventional monitors in endoscopic surgery. Materials and methods: This prospective, observational and comparative study recruited 72 participants consisting of novices (n= 28), intermediate-level (n= 24) and experts (n= 20). Participants performed ureteroscopy, within an inflatable operating environment, using a validated training model and the HoloLens mixed-reality device as a monitor. Novices also completed the assigned task using conventional monitors; whilst the experienced groups did not, due to their extensive familiarity. Outcome measures were procedural completion time and performance evaluation (OSATS) score. A final evaluation survey was distributed amongst all participants. Results: The HoloLens facilitated improved outcomes for procedural times (absolute difference, − 73 s; 95% CI − 115 to − 30; P= 0.0011) and OSAT scores (absolute difference, 4.1 points; 95% CI 2.9–5.3; P< 0.0001) compared to conventional monitors. Feedback evaluation demonstrated 97% of participants agreed or strongly agreed that the HoloLens will have a role in surgical education (mean rating, 4.6 of 5; 95% CI 4.5–4.8). Furthermore, 95% of participants agreed or strongly agreed that the HoloLens is feasible to introduce clinically and will have a role within surgery (mean rating, 4.4 of 5; 95% CI 4.2–4.5). Conclusion: This study demonstrates that the device facilitated improved outcomes of performance in novices and was widely accepted as a surgical visual aid by all groups. The HoloLens represents a feasible alternative to the conventional setup, possibly by aligning the surgeon’s visual-motor axis.- Published
- 2020
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25. Host and Graft Thickness after Descemet Stripping Endothelial Keratoplasty for Fuchs Endothelial Dystrophy
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Ahmed, Kamran A., McLaren, Jay W., Baratz, Keith H., Maguire, Leo J., Kittleson, Katrina M., and Patel, Sanjay V.
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Political corruption ,Endothelium ,Health - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ajo.2010.05.011 Byline: Kamran A. Ahmed (a), Jay W. McLaren (b), Keith H. Baratz (b), Leo J. Maguire (b), Katrina M. Kittleson (b), Sanjay V. Patel (b) Abstract: To determine relationships between vision, forward scatter, and total corneal and graft thicknesses after Descemet stripping endothelial keratoplasty (DSEK). Author Affiliation: (a) Mayo Medical School, Mayo Clinic, Rochester, Minnesota (b) Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota Article History: Accepted 13 May 2010 Article Note: (footnote) Supplemental Material available at AJO.com.
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- 2010
26. Formulation development and characterization of highly water-soluble drug-loaded extended-release pellets prepared by extrusion–spheronization technique
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Nasiri, Muhammad, Yousuf, Rabia, Shoaib, Muhammad, Zaheer, Kamran, Ali, Tariq, Ahmed, Kamran, Qazia, Faaiza, and Anwer, Sohail
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The objectives of current study were (a) to prepare extended-release plain (without polymers) and matrix pellets of itopride hydrochloride (ITP) by extrusion and spheronization technique, (b) to control the initial fast release of drug from the matrix pellets by coating using ethylcellulose, Eudragit®RL/RS100 (2:1), and Kollicoat®SR 30D, and (c) to investigate the influence of different types and concentration of coating polymers on release of highly water-soluble drug. The plain pellet contained microcrystalline cellulose and lactose without polymer, whereas matrix pellet formulations were composed of hydroxypropyl methylcellulose (HPMC K4M, K15M, and K100M) and ethylcellulose (EC 7 cps). Matrix pellet formulations failed to control the drug release, up to targeted period of 12 h. Five pellet formulations—one without polymer (F1) and one from each polymer category (F4, F7, F10, and F13)—were screened out for coating using different types and levels of polymers. The DDSolver (an add-in software for MS Excel) was used to analyze the dissolution profile data for drug release kinetics. However, drug release from pellet formulation (F7) containing HPMC as a matrix former and coated with EC followed zero-order kinetics (R2= 0.897–0.998). The release mechanism of EC-coated formulations F7, F10, and F13 was non-Fickian diffusion (anomalous transport), whereas F1 and F4 were Fickian diffusion mechanism. The stability studies of all 5% EC-coated ITP pellet formulations were conducted at room and accelerated temperature as per ICH guidelines, and results were found satisfactory. It is concluded that ethylcellulose other than Eudragit®RL/RS100 (2:1) and Kollicoat®SR 30D was found to be an excellent release controlling agent for ITP which showed good controlled-release characteristics.
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- 2019
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27. Validity assessment of a simulation module for robot-assisted thoracic lobectomy
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Whittaker, George, Aydin, Abdullatif, Raveendran, Sinthuri, Dar, Faizan, Dasgupta, Prokar, and Ahmed, Kamran
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Background Training for robot-assisted thoracic lobectomy remains an issue, prompting the development of virtual reality simulators. Our aim was to assess the construct and face validity of a new thoracic lobectomy module on the RobotiX Mentor, a robotic surgery simulator. We also aimed to determine the acceptability and feasibility of implementation into training.Methods This prospective, observational, and comparative study recruited novice (n = 16), intermediate (n = 9), and expert (n = 5) participants from King's College London, the 25th European Conference on General Thoracic Surgery, and the Society of Robotic Surgery conference 2018. Each participant completed two familiarization tasks followed by the Guided Robotic Lobectomy module and an evaluation questionnaire. Outcome measures were compared using Mann-Whitney Utests.Results Construct validity was demonstrated in 12/21 performance evaluation metrics. Significant differences between groups were found in all metrics including: time taken to complete module, vascular injury, respect for tissue, number of stapler firings, time instruments out of view, number of instrument collisions, and number of movements. Participants deemed aspects of the simulator (mean 3/5) and module (3/5) as realistic and rated the simulator as both acceptable (3.8/5) and feasible (3.8/5) for robotic surgical training.Conclusions Face validity, acceptability, and feasibility were established for the thoracic lobectomy module of the RobotiX Mentor simulator. Moderate evidence of construct validity was also demonstrated. With further work, this simulation module could help to reduce the initial part of the learning curve for trainees and decrease the risk of errors during live training.
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- 2019
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28. Nontechnical Skills in Surgery: A Systematic Review of Current Training Modalities
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Ounounou, Esther, Aydin, Abdullatif, Brunckhorst, Oliver, Khan, M. Shamim, Dasgupta, Prokar, and Ahmed, Kamran
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The complexity of the operating room requires a surgeon to have both technical ability and an array of nontechnical skills. The emphasis on technical skills during surgical training is well established, however it is deficiencies in nontechnical skills that have been identified as the main cause of errors in the operating room.
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- 2019
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29. Robot-assisted laparoscopic pyeloplasty: a single-centre experience
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Wood, Thomas, Raison, Nicholas, El-Hage, Oussama, Ahmed, Kamran, Cahill, Declan, Challacombe, Benjamin, Khan, Muhammad, and Dasgupta, Prokar
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Ureteropelvic junction obstruction (UPJO) is characterised by an obstruction compromising the passage of urine from the renal pelvis into the ureter, and can be corrected by Robot-Assisted Laparoscopic Pyeloplasty (RALP). We aimed to evaluate the surgical outcomes of RALP, and examine the rates of true pain resolution following the procedure. We retrospectively explored the records of all patients who underwent RALP between April 2005 and January 2017. Measures of success were defined as the prevention of deterioration in split renal function and resolution of obstruction, and the resolution or improvement in subjective pain levels. 83 patients were included in this series. Mean patient age was 40.8 years. 38 patients had a left sided RALP, whilst 45 underwent RALP on the right. Crossing vessels were identified in 53.0% of patients. Mean operative time was 148.0 min. 68 patients had pain as their presenting feature. Following RALP, the pain resolved in 69.2% (n= 47), improved in 26.5% (n= 18), and remained the same in 4.4% (n= 3). 11.8% (n= 8) of patients required referral to other specialities for pain management. Success from a radiological perspective of cleared obstruction and arrest of deteriorating renal function was 97.6%. Our individual outcomes demonstrate a high success rate regarding resolution of obstruction and preventing deterioration in renal function. We also report that a number of patients, who despite meeting the radiological criteria to undergo RALP, had alternate underlying causes for their pain symptoms. For this reason, we propose that the primary measure of success for RALP should be based on renal function and radiological outcomes, rather than the outcomes relating to pain. Both surgeons and patients should be aware that whilst RALP is a highly successful procedure, persistence of pain may be due to overlapping clinical conditions which can be managed by a multidisciplinary approach.
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- 2018
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30. Development of a technical checklist for the assessment of suturing in robotic surgery
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Guni, Ahmad, Raison, Nicholas, Challacombe, Ben, Khan, Shamim, Dasgupta, Prokar, and Ahmed, Kamran
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With the increased use of simulation for surgical training, there is a need for objective forms of assessment to evaluate trainees. The Global Evaluative Assessment of Robotic Skills (GEARS) is widely used for assessing skills in robotic surgery, but there are no recognised checklist scoring systems. This study aimed to develop a checklist for suturing in robotic surgery. A suturing checklist for needle driving and knot tying was constructed following evaluation of participants performing urethrovesical anastomoses. Key procedural steps were identified from expert videos, while assessing novice videos allowed identification of common technical errors. 22 novice and 13 expert videos were marked on needle driving, while 18 novices and 10 experts were assessed on knot tying. Validation of the finalised checklist was performed with the assessment of 39 separate novices by an expert surgeon and compared to GEARS scoring. The internal consistency of the preliminary checklist was high (Cronbach’s alpha = 0.870 for needle driving items; 0.736 for knot tying items), and after removal of poorly correlating items, the final checklist contained 23 steps. Both the needle driving and knot tying categories discriminated between novices and experts, p< 0.005. While the GEARS score demonstrated construct validity for needle driving, it could not significantly differentiate between novices and experts for knot tying, p= 0.286. The needle driving category significantly correlated with the corresponding GEARS scores (rs= 0.613, p< 0.005), but the correlation for knot tying was insignificant (rs= 0.296, p= 0.127). The pilot data indicates the checklist significantly correlated with the GEARS score (p< 0.005). This study reports the development of a valid assessment tool for suturing in robotic surgery. Given that checklists are simple to use, there is significant scope for this checklist to be used in surgical training.
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- 2018
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31. Aptovision: Aptovision.com
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Ahmed, Kamran
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Mass communications - Abstract
'It is a well-known fact that IP-based technologies have taken over AV distribution in the consumer space (e.g. Skype, iTunes, YouTube). It should come as no surprise then that the [...]
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- 2016
32. Use of electronic tools for evidence-based preparedness and response to the COVID-19 pandemic in the WHO African region
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Impouma, Benido, Wolfe, Caitlin M, Mboussou, Franck, Farham, Bridget, Bukhari, Arish, Flahault, Antoine, Lee, Theresa M, Mlanda, Tamayi, Ndumbi, Patricia, Ngom, Roland, Okot, Charles, Moussana, Fleury, Williams, George Sie, Moussongo, Alden, Talisuna, Ambrose, Kasolo, Francis, Ahmed, Kamran, and Keiser, Olivia
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- 2020
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33. Radiosensitivity of Lung Metastases by Primary Histology and Implications for Stereotactic Body Radiation Therapy Using the Genomically Adjusted Radiation Dose
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Ahmed, Kamran A., Scott, Jacob G., Arrington, John A., Naghavi, Arash O., Grass, G. Daniel, Perez, Bradford A., Caudell, Jimmy J., Berglund, Anders E., Welsh, Eric A., Eschrich, Steven A., Dilling, Thomas J., and Torres-Roca, Javier F.
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We assessed the radiosensitivity of lung metastases on the basis of primary histologic type by using a validated gene signature and model lung metastases for the gnomically adjusted radiation dose (GARD).
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- 2018
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34. The Validation of a Novel Robot-Assisted Radical Prostatectomy Virtual Reality Module
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Harrison, Patrick, Raison, Nicholas, Abe, Takashige, Watkinson, William, Dar, Faizan, Challacombe, Ben, Van Der Poel, Henk, Khan, Muhammad Shamim, Dasgupa, Prokar, and Ahmed, Kamran
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To perform the first validation of a full procedural virtual reality robotic training module and analysis of novice surgeon’s learning curves.
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- 2018
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35. The Effect of Visual-Spatial Ability on the Learning of Robot-Assisted Surgical Skills
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Abe, Takashige, Raison, Nicholas, Shinohara, Nobuo, Shamim Khan, M., Ahmed, Kamran, and Dasgupta, Prokar
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The aim of this study was to determine the correlation of visual-spatial ability with progression along the learning curve for robotic surgical skills training.
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- 2018
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36. Establishing objective benchmarks in robotic virtual reality simulation at the level of a competent surgeon using the RobotiX Mentor simulator
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Watkinson, William, Raison, Nicholas, Abe, Takashige, Harrison, Patrick, Khan, Shamim, Van der Poel, Henk, Dasgupta, Prokar, and Ahmed, Kamran
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BackgroundTo establish objective benchmarks at the level of a competent robotic surgeon across different exercises and metrics for the RobotiX Mentor virtual reality (VR) simulator suitable for use within a robotic surgical training curriculum.MethodsThis retrospective observational study analysed results from multiple data sources, all of which used the RobotiX Mentor VR simulator. 123 participants with varying experience from novice to expert completed the exercises. Competency was established as the 25th centile of the mean advanced intermediate score. Three basic skill exercises and two advanced skill exercises were used.SettingKing’s College London.Participants84 Novice, 26 beginner intermediates, 9 advanced intermediates and 4 experts were used in this retrospective observational study.ResultsObjective benchmarks derived from the 25th centile of the mean scores of the advanced intermediates provided suitably challenging yet also achievable targets for training surgeons. The disparity in scores was greatest for the advanced exercises. Novice surgeons are able to achieve the benchmarks across all exercises in the majority of metrics.ConclusionWe have successfully created this proof-of-concept study, which requires validation in a larger cohort. Objective benchmarks obtained from the 25th centile of the mean scores of advanced intermediates provide clinically relevant benchmarks at the standard of a competent robotic surgeon that are challenging yet also attainable. That can be used within a VR training curriculum allowing participants to track and monitor their progress in a structured and progressional manner through five exercises. Providing clearly defined targets, ensuring that a universal training standard has been achieved across training surgeons.
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- 2018
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37. Development and validation of a tool for non-technical skills evaluation in robotic surgery—the ICARS system
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Raison, Nicholas, Wood, Thomas, Brunckhorst, Oliver, Abe, Takashige, Ross, Talisa, Challacombe, Ben, Khan, Mohammed, Novara, Giacomo, Buffi, Nicolo, Poel, Henk, McIlhenny, Craig, Dasgupta, Prokar, and Ahmed, Kamran
- Abstract
Non-technical skills (NTS) are being increasingly recognised as vital for safe surgical practice. Numerous NTS rating systems have been developed to support effective training and assessment. Yet despite the additional challenges posed by robotic surgery, no NTS rating systems have been developed for this unique surgical environment. This study reports the development and validation of the first NTS behavioural rating system for robotic surgery. A comprehensive index of all relevant NTS behaviours in robotic surgery was developed through observation of robotic theatre and interviews with robotic surgeons. Using a Delphi methodology, a panel of 16 expert surgeons was consulted to identify behaviours important to NTS assessment. These behaviours were organised into an appropriate assessment template. Experts were consulted on the feasibility, applicability and educational impact of ICARS. An observational trial was used to validate ICARS. 73 novice, intermediate and expert robotic surgeons completed a urethrovesical anastomosis within a simulated operating room. NTS were tested using four scripted scenarios of increasing difficulty. Performances were video recorded. Robotic and NTS experts assessed the videos post hoc using ICARS and the standard behavioural rating system, NOn-Technical Skills for Surgeons (NOTSS). 28 key non-technical behaviours were identified by the expert panel. The finalised behavioural rating system was organised into four principle domains and seven categories. Expert opinion strongly supported its implementation. ICARS was found to be equivalent to NOTSS on Bland–Altman analysis and accurately differentiated between novice, intermediate and expert participants, p= 0.01. Moderate agreement was found between raters, Krippendorff’s alpha = 0.4. The internal structure of ICARS was shown to be consistent and reliable (median Cronbach alpha = 0.92, range 0.85–0.94). ICARS is the first NTS behavioural rating system developed for robotic surgery. Initial validation has shown it to be an effective and reliable tool. Implementation of ICARS will supported structured training and assessment of NTS within the robotic surgical curriculum.
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- 2017
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38. Commentary: From Postoperative to Preoperative: A Case Series of Hypofractionated and Single-Fraction Neoadjuvant Stereotactic Radiosurgery for Brain Metastases
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Dohm, Ammoren E., Oliver, Daniel E., Michael Yu, Hsiang-Hsuan, and Ahmed, Kamran A.
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- 2022
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39. Ownership structure and voluntary disclosure: A synthesis of empirical studies
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Khlif, Hichem, Ahmed, Kamran, and Souissi, Mohsen
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In this article, we meta-analyse 69 empirical studies assessing the association between corporate voluntary disclosure and ownership concentration and types, and how institutional characteristics and research design moderate these relationships. Our overall analyses show that state, foreign and institutional ownerships have a positive effect but managerial ownership and ownership concentration have a negative effect on voluntary disclosure. Since the overall effect may conceal the underlying factors that cause heterogeneity in the effect size distribution, we select two important institutional factors: country-level investor protection and the equity market development, and research design and journal quality, to explain the mixed and conflicting findings. Our results emphasise the need to consider legal and institutional characteristics, and researcher induced-artefacts, in understanding the role of ownership structure and identity in corporate voluntary disclosure.
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- 2017
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40. Nontechnical skill training and the use of scenarios in modern surgical education
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Brunckhorst, Oliver, Khan, Muhammad S., Dasgupta, Prokar, and Ahmed, Kamran
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- 2017
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41. Current Status of Simulation-based Training Tools in Orthopedic Surgery: A Systematic Review
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Morgan, Michael, Aydin, Abdullatif, Salih, Alan, Robati, Shibby, and Ahmed, Kamran
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To conduct a systematic review of orthopedic training and assessment simulators with reference to their level of evidence (LoE) and level of recommendation.
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- 2017
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42. Novel Opportunities to Use Radiation Therapy with Immune Checkpoint Inhibitors for Melanoma Management
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Ahmed, Kamran A., Kim, Sungjune, and Harrison, Louis B.
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Immunotherapy has revolutionized the systemic management of numerous malignancies. Nowhere has the proven benefit of these agents in clinical practice been more evident than in the management of advanced melanoma. Numerous preclinical studies have revealed the potential benefit of immune-priming radiotherapy in stimulating tumor-specific immune responses. This signal for immune activation may lead to clinically relevant synergy with immune checkpoint inhibitors against malignant cells. In this review, the authors summarize the current data outlining the role radiation therapy may play in the management of advanced melanoma alongside immune checkpoint inhibitors.
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- 2017
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43. Training Tools for Nontechnical Skills for Surgeons—A Systematic Review
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Wood, Thomas Charles, Raison, Nicholas, Haldar, Shreya, Brunckhorst, Oliver, McIlhenny, Craig, Dasgupta, Prokar, and Ahmed, Kamran
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Development of nontechnical skills for surgeons has been recognized as an important factor in surgical care. Training tools for this specific domain are being created and validated to maximize the surgeon’s nontechnical ability. This systematic review aims to outline, address, and recommend these training tools.
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- 2017
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44. Modular Training for Robot-Assisted Radical Prostatectomy: Where to Begin?
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Lovegrove, Catherine, Ahmed, Kamran, Novara, Giacomo, Guru, Khurshid, Mottrie, Alex, Challacombe, Ben, der Poel, Henk Van, Peabody, James, and Dasgupta, Prokar
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Effective training is paramount for patient safety. Modular training entails advancing through surgical steps of increasing difficulty. This study aimed to construct a modular training pathway for use in robot-assisted radical prostatectomy (RARP). It aims to identify the sequence of procedural steps that are learnt before surgeons are able to perform a full procedure without an intervention from mentor.
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- 2017
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45. Priming radioimmunotherapy with external beam radiation in patients with relapsed low grade non-Hodgkin lymphoma
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Abuodeh, Yazan, Ahmed, Kamran, Echevarria, Michelle, Naghavi, Arash, Grass, G. Daniel, Robinson, Timothy J., Tomblyn, Michael, Shah, Bijal, Chavez, Julio, Bello, Celeste, El-Haddad, Ghassan, Harrison, Louis, and Kim, Sungjune
- Abstract
Background: The aim of this study was to evaluate the outcomes of priming salvage radioimmunotherapy (RIT) with a low dose of external beam radiotherapy (EBRT) in patients with relapsed low grade non-Hodgkin lymphoma (LG-NHL).Methods: Patients who received salvage RIT with or without 2 × 2 Gy EBRT between March 2009 and February 2013 were retrospectively reviewed at a single institution. Planning target volume (PTV) for EBRT was created by adding a 1–2 cm expansion to the gross tumor volume depending on the anatomical location. Kaplan−Meier method vialog-rank was employed to analyze the endpoints freedom from progression (FFP) and overall survival (OS).Results: We identified 22 patients who received salvage RIT without chemotherapy with a median follow up of 34 months. Of these, 9 (41%) patients were treated with EBRT immediately prior to RIT, and 13 (59%) received salvage RIT alone. Median FFP was not reached in patients who underwent combination treatment, while it was 9 months for patients treated with RIT alone (p= 0.02). OS for all patients at 36 months was 80.3% with no significant difference between the two groups (p= 0.88). On univariate analysis, the addition of EBRT was associated with improved FFP [hazard ratio (HR) = 4.17; 95% confidence interval (CI), 1.24–19.1; p= 0.02)]. No long term toxicities were reported in both groups.Conclusions: RIT outcomes and effects were improved with addition of low-dose EBRT immediately prior to it, in the treatment of relapsed LG-NHL with no additional toxicity. This study is hypothesis-generating and the findings should be validated in prospective studies.
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- 2017
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46. Current Status of Simulation in Otolaryngology: A Systematic Review
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Musbahi, Omar, Aydin, Abdullatif, Al Omran, Yasser, Skilbeck, Christopher James, and Ahmed, Kamran
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Otolaryngology is a highly technical and demanding specialty and the requirements for surgical trainees to acquire proficiency remains challenging. Simulation has been purported to be an effective tool in assisting with this. The aim of this systematic review is to identify the available otolaryngology simulators, their status of validation, and evaluation the level of evidence behind each training model and thereby establish a level of recommendation.
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- 2017
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47. Training, assessment and accreditation in surgery
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Aydin, Abdullatif, Fisher, Rebecca, Khan, Muhammad Shamim, Dasgupta, Prokar, and Ahmed, Kamran
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- 2017
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48. Formulation development and optimization of taste-masked azithromycin oral suspension with ion exchange resins: Bioanalytical method development and validation, in vivo bioequivalence study, and in-silicoPBPK modeling for the paediatric population
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Siddiqui, Fahad, Shoaib, Muhammad Harris, Ahmed, Farrukh Rafiq, Qazi, Faaiza, Yousuf, Rabia Ismail, Usmani, Muhammad Talha, Saleem, Muhammad Talha, and Ahmed, Kamran
- Abstract
The study is based on preparing taste-masked oral suspension of azithromycin using ion exchange resins Kyron T135 and Doshion-P542 AB. The complexation process was optimized through Design of Experiment (DOE), and the resins-complexes were characterized by bitterness score, differential scanning calorimetry (DSC), fourier transform infra-red spectrophotometry (FTIR) and powder x-ray diffraction (PXRD). The complexes were further formulated and optimized through Central Composite Design (CCRD) into oral suspension using xanthan gum, hydroxypropyl cellulose, tri-basic sodium phosphate, and sucrose. To obtain the optimized product, the trial batches were tested for sedimentation ratio and viscosity in comparison to the reference product followed by assay and studies of drug-release kinetics. To perform bioequivalence of the optimized formulations against the reference product, an LC-MS/MS based bio-analytical method was developed and validated followed by a three-period cross over study. The pharmacokinetic parameters Cmax, Tmax, AUC0-tand AUC 0-∞were obtained through non-compartmental analysis (NCA) using log-transformed data. Moreover, physiologically based pharmacokinetic (PBPK) modelling of the in-vitrodata was carried out to predict the pharmacokinetics of the optimized formulations in the intended paediatric population. Kyron T-135 yielded the best loading efficiency at a drug resin ratio of 1:1.35 and Doshion-P542 AB at 1:3.25, while stirring and swelling time of 30 min for Kyron T-135 yielded optimum drug loading. In case of Doshion P-542 AB the optimum time was 22.5 and 30 min for stirring and swelling respectively. The bitterness score proved the tastelessness of the drug resin complex. The optimized formulation with Kyron (formulation code K4) and Doshion (formulation code D6) were selected as optimum on the basis of similar quality attributes to the reference product. The drug dissolution kinetics revealed first order drug release. The developed bioanalytical method was found to be sensitive and linear in the range of 2–500 ng/mL showing accuracy within 101.32–106.68%. Both optimized formulations (K4 and D6) were found to be bioequivalent with geometric mean ratio of Cmax, Tmax, AUC0-tand AUC 0-∞within 90% C.I. in silicoPBPK based predictive pharmacokinetics in the paediatric population was successfully estimated for the developed formulations.
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- 2023
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49. Simulation-based training and assessment in urological surgery
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Aydin, Abdullatif, Raison, Nicholas, Khan, Muhammad Shamim, Dasgupta, Prokar, and Ahmed, Kamran
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Simulation has become widely accepted as a supplementary method of training. Within urology, the greatest number of procedure-specific models and subsequent validation studies have been carried out in the field of endourology. Many generic-skills simulators have been created for laparoscopic and robot-assisted surgery, but only a limited number of procedure-specific models are available. By contrast, open urological simulation has only seen a handful of validated models. Of the available modalities, virtual reality (VR) simulators are most commonly used for endourology and robotic surgery training, the former also employing many high-fidelity bench models. Smaller dry-lab and ex vivo animal models have been used for laparoscopic and robotic training, whereas live animals and human cadavers are widely used for full procedural training. Newer concepts such as augmented-reality (AR) models and patient-specific simulators have also been introduced. Several curricula, including one recommended within, have been produced, incorporating various different training modalities and nontechnical skills training techniques. Such curricula and validated models should be used in a structured fashion to supplement operating room training.
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- 2016
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50. Outcomes Following Hypofractionated Stereotactic Radiotherapy in the Management of Brain Metastases
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Ahmed, Kamran A., Sarangkasiri, Siriporn, Chinnaiyan, Prakash, Sahebjam, Solmaz, Yu, Hsiang-Hsuan Michael, Etame, Arnold B., and Rao, Nikhil G.
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- 2016
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