Atif Khan - Academia.edu (original) (raw)

Papers by Atif Khan

Machine Translation, (hereafter in this document referred to as the "MT") faces a lot o... more Machine Translation, (hereafter in this document referred to as the "MT") faces a lot of complex problems from its origination. Extracting multiword expressions is also one of the complex problems in MT. Finding multiword expressions during translating a sentence from English into Urdu, through existing solutions, takes a lot of time and occupies system resources. We have designed a simple relational data approach, in which we simply set a bit in dictionary (database) for multiword, to find and handle multiword expression. This approach handles multiword efficiently.

1 supervised learning classification: predict the class of an instance of data regression: predic... more 1 supervised learning classification: predict the class of an instance of data regression: prediction of a numeric value 2 unsupervised learning clustering: group similar items together

Annals of International medical and Dental Research, 2017

Variations in the arterial pattern of the upper limb are very common as observed in many cadaveri... more Variations in the arterial pattern of the upper limb are very common as observed in many cadaveric and angiographic studies. Knowledge of variations in the origin and course of the radial artery is important because they are used for many diagnostic procedures as well as vascular and reconstructive surgeries like coronary angiography, percutaneous coronary intervention and coronary artery bypass surgery. During routine dissection in our institute, we observed a case of high origin of the radial artery in a 33 year old male cadaver. It was found to be unilateral; on left side, radial artery was taking origin from 3 rd part of the axillary artery at the lower border of pectoralis minor before the origin of subscapular artery and anterior circumflex humeral artery. It had a superficial course in the arm crossing the median nerve from medial to lateral side. The further course of this superficial radial artery in the forearm was normal and it terminated by forming a deep Palmar arch in hand. These variations may be of great clinical implications for vascular and plastic surgeons and radiologists. Superficial course of radial artery makes it vulnerable to accidental injuries.

Journal of applied clinical medical physics, Sep 8, 2016

This work investigated the possibility of using proton beam for total body irradiation (TBI). We ... more This work investigated the possibility of using proton beam for total body irradiation (TBI). We hypothesized the broad-slow-rising entrance dose from a monoenergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific compensator or beam spoiler. The hypothesis was first tested by simulating 250 MeV, 275 MeV, and 300 MeV protons irradiating a wedge-shaped water phantom in a paired opposing arrangement using Monte Carlo (MC) method. To allow ±7.5% dose variation, the maximum water equivalent thickness (WET) of a treatable patient separation was 29 cm for 250 MeV proton, and >40 cm for 275 MeV and 300 MeV proton. The compared 6 MV photon can only treat patients with up to 15.5 cm water-equivalent separation. In the second step, we simulated the dose deposition from the same beams on a patient's whole-body CT scan. The maximum patient separation in WET was 23 cm. The calculated whole-b...

Lancet (London, England), Jan 23, 2016

American journal of clinical oncology, Jan 20, 2015

COMMENTARY Recently, mature data were published from the MA.20 and European Organization for the ... more COMMENTARY Recently, mature data were published from the MA.20 and European Organization for the Research and Treatment of Cancer (EORTC) 22922 trials, providing clinicians with increasing data supporting the value of regional nodal irradiation (RNI). The MA.20 randomized 1832 women with highrisk node-negative (T3, T2 with <10 nodes removed and grade 3/estrogen receptor-negative/lymphovascular space invasion) or node-positive disease to receive whole breast irradiation with or without RNI (axillary apex, internal mammary, supraclavicular) with >80% of patients having 1 to 3 nodes positive. Ten-year outcomes demonstrated an improvement in disease-free survival (82% vs. 77%) with reductions in distant metastases and locoregional recurrences with the addition of RNI with modest increases in pneumonitis (1.2% vs. 0.2%) and lymphedema (8.4% vs. 4.5%). Similarly, the EORTC trial randomized 4004 women with centromedial tumors or lateral tumors with axillary disease to receive radiation with or without inclusion of the internal mammary chain and medial supraclavicular nodes; 43% of patients had 1 to 3 nodes involved. Results of the study demonstrated improvements in disease-free survival (72% vs. 69%), distant metastases-free survival, and reductions in breast cancer mortality with a trend for improved overall survival. These results confirm data from previous studies (subset analyses of postmastectomy randomized trials, meta-analyses) that demonstrated improvement in outcomes with radiation therapy (including RNI) for patients with 1 to 3 nodes positive. Recent commentary following the publication of these studies has questioned the role of RNI despite the aforementioned improvements in disease-free survival, distant metastases, and locoregional control due to a lack of survival benefit in these trials. However, it should be noted that improvements in locoregional control, disease-free survival, distant metastases, and breast cancer mortality have justified the utilization of surgical, systemic, and radiotherapeutic techniques in the past and continue to do so. For instance, the National Surgical Adjuvant Breast and Bowel Project B28 trial has resulted in the widespread addition of taxanes to anthracycline-based chemotherapy, and the Cancer and Leukemia Group B 9741 results resulted in increasing utilization of dose-dense chemotherapy regimens despite lower than expected outcome events. Further, the EORTC trial demonstrated a trend for improvement in overall survival with the potential for improved survival with further follow-up. Arguments for limiting RNI presented include a reduction in the rates of local recurrence, improvements in systemic therapy, and differences in nodal sampling compared with recent studies. With regards to the improvement in locoregional control over time, recent data demonstrate locoregional recurrence rates exceeding 10% in patients even in patients with low-volume nodal disease with modern systemic therapy. Systemic therapy has evolved over the past few decades; however, taxanes were utilized in these studies (26% in MA.20; unknown in EORTC 22922) and limited data are available suggesting an improvement in locoregional control with trastuzumab, with the benefit more likely associated with radiotherapy. Similarly, aromatase inhibitors have demonstrated a reduction in recurrences but these were primarily distant recurrences and contralateral breast cancers rather than local recurrences. Although management of the axilla continues to evolve, there is insufficient evidence to support that the results of the American College of Surgeons Oncology Group Z011 and After Mapping Axilla, Radiotherapy or Surgery trials is from systemic therapy and in the case of the After Mapping Axilla, Radiotherapy or Surgery trial is more likely due to the RNI. Similarly, although there is a difference in the number of nodes sampled (12 to 15 vs. 17), there is insufficient evidence to support that this difference would lead to a difference in the clinical outcomes noted. RNI can be associated with toxicity though the rates remain low; the EORTC trial demonstrated an increase in pulmonary fibrosis although it was <5% with no difference in other late toxicities. Similarly, MA.20 demonstrated a small increase in pneumonitis as well as chronic lymphedema and skin changes. However, the cost-benefit of an improvement in disease-free survival and potentially overall survival with longer follow-up outweighs the small increase in toxicity. There is a concern regarding the heterogeneity of these trials. A recent editorial recommended RNI for those with Z4 nodes positive but suggested that RNI be limited in patients with 1 to 3 nodes positive to those with high-risk From the *Department of Radiation Oncology, Cleveland Clinic, Taussig Cancer Institute, Cleveland; wDepartment of Radiation Oncology, Northeast Ohio Medical University, Rootstown, OH; zDepartment of Radiation Oncology, Rutgers Robert Wood Johnson Medical…

A 40-year old man was prescribed doxycycline 200 mg once daily for the symptoms of cough and muco... more A 40-year old man was prescribed doxycycline 200 mg once daily for the symptoms of cough and mucopurulent sputum. The patient had retrosternal chest pain one hour after the fourth dose of doxycycline. The pain increased gradually and was radiating to the back. He also had difficult and painful swallowing. Barium swallow revealed longitudinal oriented barium pool with edematous margins on the walls of the mid-esophagus. The findings are suggestive of esophageal ulceration. He is a nonsmoker, non alcoholic and no history of aspirin or non-steroidal anti inflammatory drugs (NSAIDs) intake in the past one month. There is no history of any other concomitant medication. The therapy consisted of doxycycline withdrawal along with treatment with sucralfate, famotidine and liquid antacids. His symptoms gradually disappeared within 10 days.). In light of the strong temporal relationship between taking the drugs and the onset of the esophageal ulceration and clinical recovery of the patient on stopping the drug we believe that the event could be due to doxycycline .The strength of association was examined using the "Naranjo's Adverse drug Reaction Probability Scale", in which a score of +7 was obtained suggesting a 'probable' link.

Nanotechnology, Jan 13, 2015

We report a facile and highly effective n-doping method using hydrazine solution to realize enhan... more We report a facile and highly effective n-doping method using hydrazine solution to realize enhanced electron conduction in a WSe2 field-effect transistor (FET) with three different metal contacts of varying work functions-namely, Ti, Co, and Pt. Before hydrazine treatment, the Ti- and Co-contacted WSe2 FETs show weak ambipolar behaviour with electron dominant transport, whereas in the Pt-contacted WSe2 FETs, the p-type unipolar behaviour was observed with the transport dominated by holes. In the hydrazine treatment, a p-type WSe2 FET (Pt contacted) was converted to n-type with enhanced electron conduction, whereas highly n-doped properties were achieved for both Ti- and Co-contacted WSe2 FETs with on-current increasing by three orders of magnitude for Ti. All n-doped WSe2 FETs exhibited enhanced hysteresis in their transfer characteristics, which opens up the possibility of developing memories using transition metal dichalcogenides.

Molecular Cancer Therapeutics, 2015

Glioblastoma (GBM) is the most frequent and lethal brain cancer. The lack of early detection meth... more Glioblastoma (GBM) is the most frequent and lethal brain cancer. The lack of early detection methods, the presence of rapidly growing tumor cells, and the high levels of recurrence due to chemo- and radioresistance make this cancer an extremely difficult disease to treat. Emerging studies have focused on inhibiting AKT activation; here, we demonstrate that in primary GBM tumor samples, full-dose inhibition of AKT activity leads to differential responses among samples in the context of cell death and self-renewal, reinforcing the notion that GBM is a heterogeneous disease. In contrast, low-dose AKT inhibition when combined with fractionation of radiation doses leads to a significant apoptosis-mediated cell death of primary patient–derived GBM cells. Therefore, low-dose–targeted therapies might be better for radiosensitization of primary GBM cells and further allow for reducing the clinical toxicities often associated with targeting the AKT/PI3K/mTOR pathway. This work emphasizes the ...

Journal of Radiation Oncology, 2013

ABSTRACT

Frontiers in Oncology, 2014

Blocks have been used to protect heart from potential radiation damage in left-sided breast treat... more Blocks have been used to protect heart from potential radiation damage in left-sided breast treatments. Since cardiac motion pattern may not be fully captured on conventional 3DCT or 4DCT simulation scans, this study was intended to investigate the optimization of the heart block design taking the cardiac motion into consideration. Materials and Methods: Whole breast treatment plans using two opposed tangential fields were designed based on 4DCT simulation images for 10 left-sided breast cancer patients. Using an OBI system equipped to a Varian Linac, beam-eye viewed fluoroscopy images were acquired for each of the treatment beams after patient treatment setup, and the MLC heart blocks were overlaid onto the fluoroscopy images with an in-house software package. A non-rigid image registration and tracking algorithm was utilized to track the cardiac motion on the fluoroscopy images with minimal manual delineation for initialization, and the tracked cardiac motion information was used to optimize the heart block design to minimize the radiation damage to heart while avoiding the over-shielding that may lead to underdosing certain breast tissues. Results: Twenty-three sets of fluoroscopy images were acquired on 23 different days of treatment for the 10 patients. As expected, heart moved under the influences of both respiratory and cardiac motion. It was observed that for 16 out of the 23 treatments, heart moved beyond the planed heart block into treatment fields and MLC had to be adjusted to fully block heart. The adjustment was made for all but one patient. The number of the adjusted MLC leaves ranged from 1 to 16 (mean = 10), and the MLC leaf position adjustment ranged from 2 to 10 mm (mean = 6 mm). The added heart block areas ranged from 3 to 1230 mm 2 (mean = 331 mm 2). Conclusion: In left-sided whole breast radiation treatments, simulation CT (and 4DCT) based heart block design may not provide adequate heart protection for all the treatments. A fluoroscopy-based method has been developed to adaptively optimize the heart MLC block to achieve optimal heart protection.

IEEE Journal of Biomedical and Health Informatics, 2015

The version presented here may differ from the published version or, version of record, if you wi... more The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription.

Practical Radiation Oncology, 2013

A 41-year-old African-American male presented at an outside institution with complaint of progres... more A 41-year-old African-American male presented at an outside institution with complaint of progressively worsening double vision for 1 to 2 months, with dimming of vision in his left eye. Pertinent past medical, surgical, family, or social history consisted of previous tobacco, alcohol, and cocaine abuse. Magnetic resonance imaging (MRI) of the brain, with and without gadolinium, revealed a heterogeneously enhancing mass with numerous flow voids. The mass was centered in the region of the pineal gland and it was inseparable from the medullary velum. The mass was hyperintense on T1-weighted imaging suggesting hemorrhage or calcifications. There was associated hydrocephalus with no other abnormalities seen. The patient underwent a biopsy of the tumor. First, the patient had a right frontal ventriculoperitoneal shunt with a medium pressure Codman valve placed. During this procedure, it was noted that cerebrospinal fluid (CSF)

Proceedings of the 2nd ACM SIGHIT International Health Informatics Symposium, 2012

Modern medical decision making systems require users to manually collect and process information ... more Modern medical decision making systems require users to manually collect and process information from distributed and heterogeneous repositories to facilitate the decision making process. There are many factors (such as time, volume of information and technical ability) that can potentially compromise the quality of decisions made for patients. In this work we demonstrate and evaluate a new medical decision making support system, called OMeD, which automatically answers medical queries in real time, by collecting and processing medical information. OMeD utilizes a natural-language-like user interface (for querying) and semantic web techniques (for knowledge representation and reasoning) to answer queries. We compare OMeD to a set of standard machine learning techniques across a series of benchmarks based on simulated patient data. The conventional techniques attempt to learn the answer to a query by analyzing simulated patient records. The sparsity of the simulated data leads conventional techniques to frequently misidentify the relationships between medical concepts. In contrast, OMeD is able to reliably provide correct answers to queries. Unlike conventional automated decision support systems, OMeD also generates independently verifiable proofs for its answers, providing healthcare workers with confidence in the system's recommendations.

Urology Annals, 2014

Inguinal herniation of the urinary bladder is an extremely rare occurrence involving less than 5%... more Inguinal herniation of the urinary bladder is an extremely rare occurrence involving less than 5% of inguinal hernias reported in literature. These hernias require a high index of suspicion for their diagnosis and pose significant challenges to the operating surgeon. The majority of these hernias have been repaired by an open technique. We report two cases managed laparoscopically.

Journal of the American Society of Echocardiography, 2012

JSLS : Journal of the Society of Laparoendoscopic Surgeons, 2011

Minimally invasive surgery has revolutionized surgery for urologic disorders, and laparoscopic pr... more Minimally invasive surgery has revolutionized surgery for urologic disorders, and laparoscopic procedures have become widely available for several different ablative and reconstructive operations. Laparoscopic heminephrectomy in patients with horseshoe kidney can be a technically challenging procedure due to aberrant vessels, functional parenchyma in the isthmus, and abnormal location. We report the management of a case of symptomatic nonfunctioning left moiety of a horseshoe kidney with emphasis on its surgical technique combined with a review of the literature. Laparoscopic heminephrectomy is a feasible option in the surgical management of benign and malignant conditions of the horseshoe kidney and can be performed safely using a transperitoneal or a retroperitoneal approach.

International Journal of Radiation Oncology*Biology*Physics, 2011

Preclinical studies have shown that bevacizumab combined with radiotherapy (RT) induces a radiose... more Preclinical studies have shown that bevacizumab combined with radiotherapy (RT) induces a radiosensitizing effect. Published reports regarding the safety of combination therapy involving bevacizumab and RT are lacking. The purpose of this study was to analyze acute locoregional toxicity in patients with breast cancer receiving concurrent bevacizumab plus RT. After institutional review board approval was obtained, patients with breast cancer who received bevacizumab were identified; these patients were then cross-referenced with patients receiving RT. Toxicity was scored by the Common Terminology Criteria for Adverse Events. Patients were matched 1:1 with those who did not receive bevacizumab. Statistical analysis was performed to analyze toxicity between the two groups. Fourteen patients were identified to have received bevacizumab plus RT. All patients received bevacizumab during RT without delay or treatment breaks; there were no RT treatment breaks in all patients. No patient receiving bevacizumab plus RT experienced ≥Grade 3 toxicity; 3 matched control patients experienced a Grade 3 skin reaction. There was no difference in fatigue, radiation fibrosis, pneumonitis, or lymphedema between the two groups. Five patients (35%) developed reduction in ejection fraction; 2 with right-sided and 3 with left-sided treatment. Patients with left-sided treatment experienced a persistent reduction in ejection fraction compared with those receiving right-sided treatment. Concurrent bevacizumab and RT did not increase acute locoregional toxicity in comparison with matched control patients who did not receive RT alone. The addition of concurrent RT when treating the intact breast, chest wall, and associated nodal regions in breast cancer seems to be safe and well tolerated.