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

Papers by Nasir Khan

Updates in surgery, Jan 19, 2017

MR defecography (MRD) is an alternative to conventional defecography (CD) which allows for dynami... more MR defecography (MRD) is an alternative to conventional defecography (CD) which allows for dynamic visualisation of the pelvic floor. The aim of this study was to assess whether MRI features indicative of pelvic floor dysfunction correlated with patient-reported symptom severity. MR proctograms were matched to a prospectively-maintained functional database. Univariate and multivariate analyses were performed using pre-treatment questionnaire responses to the Birmingham Bowel, Bladder and Urinary Symptom Questionnaire (BBUSQ), Wexner Incontinence Score (WIS), and modified Obstructed Defecation Symptom (ODS) Score. 302 MRI proctograms were performed between January 2012 and April 2015. 170 patients were included. Patients with a rectocele > 2 cm (p = 0.003; OR 5.756) or MRD features suggestive of puborectalis syndrome (p = 0.025; OR 8.602) were more likely to report a higher ODS score on multivariate analysis. Lack of rectal evacuation was negatively associated with an abnormal WIS...

Journal of medical imaging and radiation oncology, Jan 17, 2017

The transverse ligament in the ankle joint has been described as a labrum-like structure in a pre... more The transverse ligament in the ankle joint has been described as a labrum-like structure in a previous cadaveric study. The purpose of this study is to assess the spectrum of abnormal changes related to this structure on imaging/MRI, and correlate these findings with other ankle joint findings and patient symptoms. A retrospective observational review of 172 ankle MRI scans was carried out independently by two fellowship trained musculoskeletal Radiologists. Correlation between abnormal labral changes, other ankle joint findings and patient symptomatology was performed. Abnormal labral changes were seen in 26% of the MRI scans (n = 44/172) and included signal change, contour abnormality with heterogeneous signal change, linear fluid filled clefts, multidirectional fluid filled clefts, and a macerated labrum. There was a statistically significant association between abnormal labral changes and the presence of Stieda process/os trigonum (P = 0.001), talocrural joint osteoarthritis (P ...

Studia Geophysica et Geodaetica, 2014

Porosity plays an important part of understanding permeability and fluid flow within the continen... more Porosity plays an important part of understanding permeability and fluid flow within the continental, crystalline rocks. Geophysical well logs are presently the most consistent means of providing continuous information for porosity estimation. However, it is difficult to interpret geophysical well logs data in crystalline rocks due to their complex geological features and the difficulty in understanding and using the complex and intensive information content in these data. Motived by the successful prediction abilities of artificial neural networks (ANN) to solve different problems in geophysics, this study explore the applicability of using ANNs to predict porosity in continental, crystalline rocks. This ANN technique is calibrated on Chinese Continental Scientific Drilling Main Hole (CCSD-MH) data, which provides core porosity data combined with four geophysical well logs (density, neutron porosity, sonic and resistivity). The data from CCSD-MH is utilized to train feed-forward backpropagation (FFBP) neural network and radial basis function (RBF) neural network to derive a relationship between geophysical well logs and porosity, and hence predict porosity accurately. The findings demonstrate that ANNs provide better performances with sets of three geophysical well logs (density, sonic and resistivity) than regression technique. Comparison of FFBP to RBF showed that RBF reveals better stability and more accurate performances than FFBP. Based on the success achieved in this study, this intelligence artificial technique can be a very advantageous tool in facilitating the task of geophysicists in the framework of research drillings in continental crust.

Journal of Ayub Medical College, Abbottabad : JAMC

Laparoscopic cholecystectomy (LC), a gold standard procedure for cholelithiasis, is associated wi... more Laparoscopic cholecystectomy (LC), a gold standard procedure for cholelithiasis, is associated with higher incidence of bile duct injuries and perioperative bleeding. These complications are of further concern when LC is carried out on patients with liver cirrhosis. Although LC is now increasingly being performed for cholelithiasis in cirrhotic patients, the safety of the procedure is debatable in this group of patients. We retrospectively analysed 82 LCs, performed between January 2002 and December 2011. in cirrhotic patients with gall stone disease for perioperative complications. Patients were sub-classified into Class A, B and C based on child-Pugh classification of severity of liver cirrhosis. Intergroup comparisons were carried out using ANOVA, and p < or = 0.05 was considered significant. LC was successfully completed in all but 3 patients (3.7%). None of the cirrhotic patients had bile duct injury. Class C patients (n = 27) had higher frequency of perioperative bleeding t...

Canadian family physician Médecin de famille canadien, 2014

We perform an automatic analysis of television news programs, based on the closed captions that a... more We perform an automatic analysis of television news programs, based on the closed captions that accompany them. Specifically, we collect all the news broadcasted in over 140 television channels in the US during a period of six months. We start by segmenting, processing, and annotating the closed captions automatically. Next, we focus on the analysis of their linguistic style and on mentions of people using NLP methods. We present a series of key insights about news providers, people in the news, and we discuss the biases that can be uncovered by automatic means. These insights are contrasted by looking at the data from multiple points of view, including qualitative assessment.

Postgraduate Medicine, 2001

Type 2 diabetes can cause serious complications even as it remains undiagnosed. Screening is reco... more Type 2 diabetes can cause serious complications even as it remains undiagnosed. Screening is recommended only in people with risk factors for the disease. The ADA recommends FPG as the test of choice, but RPG is also a practical alternative because it is easier and more convenient. Frequency of rescreening if the first screen result is normal depends on the number of risk factors present. Physicians should realize the importance of a confirmatory test and not base a diagnosis of diabetes on a single value unless the value is so high that the diagnosis is unequivocal.

Emergency Radiology, 2010

Delayed enlargement of a traumatic cerebral contusion can occur subsequent to an initial CT scan,... more Delayed enlargement of a traumatic cerebral contusion can occur subsequent to an initial CT scan, and this can lead to neurological deterioration, brain herniation, and death. Herein, we describe the case of a 76-year-old male who experienced an intracerebral hemorrhage subsequent to a fall and whose injury worsened over time. We summarize the current recommendations in the literature for when to initiate follow-up imaging in patients with traumatic head injury, the risk factors for progression, and the role of close clinical monitoring and serial imaging in managing such patients. Finally, we illustrate how these recommendations were applied in our case.

Pediatric Surgery International, 2008

Meckel's diverticulum (MD) has varied presentations and often becomes a diagnostic challenge. The... more Meckel's diverticulum (MD) has varied presentations and often becomes a diagnostic challenge. The purpose of this study was to review the various presentations of symptomatic MD and to assess the sensitivity of the Meckel's scan as a diagnostic tool in patients with bleeding MD. The hospital records of 71 consecutive patients with a diagnosis of MD from 1990 to 2005 were retrospectively reviewed. The data was assessed for age at presentation, sex, clinical features, investigations performed, surgical intervention and histopathological findings. There were 71 patients with a diagnosis of MD (age 2 days-14 years). In eight patients, MD was an incidental finding at laparotomy. The remaining 63 patients were symptomatic and presented with various clinical features. Ten patients (15.8%) had clinical features of peritonitis; of these, six had perforated MD and four had Meckel's diverticulitis at laparotomy. Nine patients (14.2%) were diagnosed as intestinal obstruction, and at laparotomy, a Meckel's band was found to be the cause of the obstruction. Nine patients (14.2%) had a patent vitellointestinal duct and presented with umbilical discharge. Thirty-five patients (55.5%) presented with episodes of bleeding per rectum or malaena. Ultrasound scans revealed intussusception in six patients requiring open reduction. Of the remaining 29 patients with bleeding per rectum, 27 underwent a Meckel's Tc99 scan that showed a positive tracer in 18 patients (66.6%) and negative in 9 (33.3%). All patients with a symptomatic MD underwent resection of the diverticulum. Histology revealed ectopic gastric mucosa in 43 patients (68.3%). MD has various presentations and can be easily misdiagnosed. It is necessary to maintain a high index of suspicion in the paediatric age group. The Meckel's scan has a poor positive predictive value and cannot be relied upon for a diagnosis in cases of bleeding MD if Tc99 scan is negative.

The Journal of Urology, 1999

Journal of Surgical Research, 2008

Background. Fetal tracheal occlusion (TO) has been investigated as a treatment option for lung hy... more Background. Fetal tracheal occlusion (TO) has been investigated as a treatment option for lung hypoplasia secondary to congenital diaphragmatic hernia (CDH). TO increases lung size, but it is unclear whether TO stimulates mature lung growth or simply induces alveolarization without concomitant bronchial development. In this study, we characterize bronchial branch development in fetal rats with CDH with or without TO through conventional histological and morphometric analysis as well as lung casting. Materials and methods. Rat dams were gavaged nitrofen at gestational day 9.5, and 3 to 4 fetuses per dam underwent fetal TO on gestational day 19 (term ‫؍‬ 22 days). Fetuses were sacrificed on day 21, the presence of CDH was confirmed, and the lung weight to body weight ratio (LW/BW) was calculated. Lung casts of all research groups were created using liquid silicon and bronchial branches were quantified from lung periphery to carina. Results. CDH fetuses had smaller LW/BW ratios and a lesser percentage (%) of airspace when compared to controls, and manifested less lung branching than controls. Fetuses treated by TO had a greater LW/BW ratio and % airspace, but did not have a different number of branch iterations. Fetuses with CDH and TO demonstrated a restoration in LW/BW ratio to control levels (P ‫؍‬ 0.42), but the number of bronchial branch iterations remained less than control animals. Conclusion. The results of this study suggest that TO in this animal model at gestational day 19 promotes distal airway proliferation but does not reverse the under-development of bronchial branching seen in lung hypoplasia due to CDH.

Acta Crystallographica Section E Structure Reports Online, 2010

The crystal structure of (II) i.e. N-(benzylidene)-4-ferrocenylaniline (Shah et al., 2007) and (I... more The crystal structure of (II) i.e. N-(benzylidene)-4-ferrocenylaniline (Shah et al., 2007) and (III) i.e. 1-(4-((1,4-Benzoquinonyl)carbonylamino)phenyl)ferrocene (Fukuzumi et al., 2002) have been published. The title compound (I) differs from these due to substituants at the N-atom. In (I) the cyclopentadienyl ring A (C6-C10), phenyl rings B (C11-C16) and C (C18-C23) are planar with r. m. s. deviations of 0.0024, 0.0020 and 0.0030 Å, respectively. The dihedral angle between A/B is 2.31 (23)° which shows that central phenyl ring is almost planar with attached cyclopentadienyl. The dihedral angle between B/C is 69.05 (8)°. The Fe-atom is at a distance of 1.6435 (17) Å from the centroid of ring A. The important bond distances [Fe-C] and bond angles [C-Fe-C] are given in Table 1. Cyclopentadienyl ring of ferrocene not attached with 4-(benzoylamino)phenyl is disordered over two set of sites with occupancy ratio of 0.548 (14):0.452 (14). There exist intramolecular H-bonding of C-H•••O type forming S(6) ring motif (Bernstein et al., 1995). The intermolecular H-bondings of C-H•••O and N-H•••O type complete R 2 1 (7) ring motif (Table 2, Fig. 2). The molecules are stabilized in the form of polymeric chains extending along the crystallographic b axis (Fig. 2). In these chains molecules are connected in helical way due to screw symmetry. S2. Experimental Solution of benzoyl chloride (0.5 ml, 4.296 mmol) in 50 ml anhydrous CHCl 3 added to the solution of ferrocenyl aniline (1.19 g, 4.296 mmol) and triethylamine (0.71 ml, 5.155 mmol) in 50 ml anhydrous CHCl 3 , at 273 K and stirred for 24 h. The completion of reaction monitored through TLC. To remove extra triethylamine and un-reacted acid chloride and the formed ammonium chloride, the mixture was extracted with distilled water (6 × 100 ml). The solution was evaporated under reduced pressure to give orange solid and re-crystallized form CH 2 Cl 2. (yield: 84%) S3. Refinement The disordered cyclopentadienyl was refined in two groups as regular pentagons of 1.42 Å. The anisotropic temperature factors of the disordered C atoms were restrained to be nearly isotropic. The H-atoms were positioned geometrically (N-H = 0.86 Å, C-H = 0.93 Å) and refined as riding with U iso (H) = xU eq (C, N), where x = 1.2 for all H-atoms. supporting information sup-2