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Role of Cardiac MRI in Complicated Cardiac Defects
Khan Yasir,Pervez Mohammad Bin,Fatimi Saulat 아시아심장혈관영상의학회 2019 Cardiovascular Imaging Asia Vol.3 No.3
Sinus of Valsalva rupture is a rare condition that results in aortocardiac shunt. Although the investigation of choice is transthoracic echocardiography, the gold standard is cardiac catheterization. We present a case of a young male with acute onset heart failure. Acute coronary syndrome blood workup was unremarkable. Transthoracic and transesophageal echocardiography revealed mild right atrial dilation with a Gerbode shunt. Right heart catheterization showed left to right shunt suggestive of acquired acute onset shunting. Eventually, a cardiac MRI revealed a ruptured sinus of Valsalva opening into the right atrium as the cause. The patient was taken to the operation theater where an aortobicaval bypass was established. A horizontal aortotomy revealed a sinus of Valsalva aneurysm arising from the right coronary sinus which was repaired using a Dacron patch. Postoperative transthoracic echocardiography showed no defect. In summary, cardiac MRI is an excellent tool for establishing a definite diagnosis for complicated cardiac defects.
Paraplegia Following Spinal Cord Contusion from an Indirect Gunshot Injury
Khuram Khan,Beatrice Dieudonne,Saqib Saeed,Sara Alothman,Yasir Saeed,Sanjiv Gray,Khuram Khan 대한신경손상학회 2018 Korean Journal of Neurotrauma Vol.15 No.1
Spinal cord injuries are debilitating and life threatening. Paraplegia due to direct traumatic gunshot injury to the spinalcord is common. The most common cause of spinal cord injury is road traffc accidents. This is followed by spinal cord injury due to a fall from a height. Most of the spinal cord injuries due to gunshot wounds occur as a result of direct traumatic effects. We present a rare case of a 49-year-old male with trauma. He developed paraplegia after a gunshot wound injuryto the neck and contusion to the spinal cord, with no direct trauma. Paraplegia due to direct gunshot injury can have manydifferent outcomes. In our case, the patient was managed conservatively, and the outcome was favorable
An overview of the role of ionic liquids in biodiesel reactions
Nawshad Muhammad,Yasir A. Elsheikh,Muhammad Ibrahim Abdul Mutalib,Zakaria Man,Ihsnullah khan,Aqeel Ahmed Bazmi,Rahmat Ali Khan,Hidayatullah Khan,Sikander Rafiq 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
The concerns on the depleting petroleum resources and increasing environmental problems have driventhe scientific community worldwide to develop large-scale non-petroleum-based alternative fuels, suchas bioethanol and biodiesel. Biodiesel produced through the transesterification of vegetable oils oranimal fats are highly attractive. On the other hand, ionic liquids which possess properties that aremoreenvironmental friendly have found significant applications as solvents and catalysts for reaction andseparation. It is also beginning to find its way in many of the chemical process applications and hasattracted significant attention including biodiesel production. This paper provides a brief overview onthe feasibility of applying ionic liquids in biodiesel production for the purpose of powering diesel enginesfor transportation and utility generation. The potential of applying ionic liquids as catalyst and solventfor enzymatic production of biodiesel from feedstock is particularly highlighted.
Alam, Tariq,Khattak, Yasir Jamil,Beg, Madiha,Raouf, Abdul,Azeemuddin, Muhammad,Khan, Asif Alam Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22
Background: In Pakistan thyroid cancer is responsible for 1.2% cases of all malignant tumors. Ultrasonography (US) is helpful in detecting cancerous thyroid nodules on basis of different features like echogenicity, margins, microcalcifications, size, shape and abnormal neck lymph nodes. We therefore aimed to calculate diagnostic accuracy of ultrasound in detection of carcinoma in thyroid nodules taking fine needle aspiration cytology as the reference standard. Materials and Methods: A cross-sectional analytical study was designed to prospectively collect data from December 2010 till December 2012 from the Department of Radiology in Aga Khan University Hospital, Karachi, Pakistan. A total of 100 patients of both genders were enrolled after informed consent via applying non-probability consecutive sampling technique. Patients referred to Radiology department of Aga Khan University to perform thyroid ultrasound followed by fine-needle aspiration cytology of thyroid nodules were included. They were excluded if proven for thyroid malignancy or if their US or FNAC was conducted outside our institution. Results: The subjects comprised 76 (76%) females and 24 males. Mean age was $41.8{\pm}SD$ 12.3 years. Sensitivity and specificity with 95%CI of ultrasound in differentiating malignant thyroid nodule from benign thyroid nodule calculated to be 91.7% (95%CI, 0.72-0.98) and 78.94% (0.68-0.87) respectively. Reported positive predictive value and negative PV were 57.9% (0.41-0.73) and 96.8% (0.88-0.99) and overall accuracy was 82%. Likelihood ratio (LR) positive was computed to be 4.3 and LR negative was 0.1. Conclusions: Ultrasonography has a high diagnostic accuracy in detecting malignancy in thyroid nodules on the basis of features like echogenicity, margins, micro calcifications and shape.
Muhammad Yasir,Haji Khan,Syed Sikander Azam,Amar Telke,Seon Won Kim,Young Ryun Chung 한국미생물학회 2013 The journal of microbiology Vol.51 No.3
In the vermicomposting of paper mill sludge, the activity of earthworms is very dependent on dietetic polysaccharides including cellulose as energy sources. Most of these polymers are degraded by the host microbiota and considered potentially important source for cellulolytic enzymes. In the present study, a metagenomic library was constructed from vermicompost (VC) prepared with paper mill sludge and dairy sludge (fresh sludge, FS) and functionally screened for cellulolytic activities. Eighteen cellulase expressing clones were isolated from about 89,000 fosmid clones libraries. A short fragment library was constructed from the most active positive clone (cMGL504) and one open reading frame (ORF) of 1,092 bp encoding an endo-β-1,4-glucanase was indentified which showed 88% similarity with Cellvibrio mixtus cellulase A gene. The endo-β-1,4-glucanase cmgl504 gene was overexpressed in Escherichia coli. The purified recombinant cmgl504 cellulase displayed activities at a broad range of temperature (25–55°C) and pH (5.5–8.5). The enzyme degraded carboxymethyl cellulose (CMC) with 15.4 U, while having low activity against avicel. No detectable activity was found for xylan and laminarin. The enzyme activity was stimulated by potassium chloride. The deduced protein and three-dimensional structure of metagenomederived cellulase cmgl504 possessed all features, including general architecture, signature motifs, and N-terminal signal peptide, followed by the catalytic domain of cellulase belonging to glycosyl hydrolase family 5 (GHF5). The cellulases cloned in this work may play important roles in the degradation of celluloses in vermicomposting process and could be exploited for industrial application in future.
Abid, Muhammad,Khan, Yasir Mehmood Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.6
This paper presents results of the effect of different bolt tightening sequences and methods on the performance of gasketed bolted flange joint using nonlinear finite element analysis. Bolt preload scatter due to elastic interactions, flange stress variation and bolt bending due to flange rotation and gasket contact stress variation is difficult to eliminate in torque control method i.e. tightening one bolt at a time. Although stretch control method (tightening more than one bolt at time) eradicates the bolt preload scatter, flange stress variation is relatively high. Flange joint's performance is compared to establish relative merits and demerits of both the methods and different bolt tightening sequences.
Muddasir Riaz KHAN,Yasir Bin TARIQ 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.5
In today’s financial economics literature, the impact of innovative family ownership and management on firm performance is a prominent concern. In this study, the existence of family firms in the listed sector of Pakistan’s economy is investigated. The objective of this study is to examine the performance-oriented relationship of family ownership and active involvement of family member at the CEO position. The theoretical perspectives that underpin this research are agency and stewardship. This analysis used a sample of 315 publicly traded companies from 2009 to 2019. The study’s primary independent variables include family influence on ownership and family CEO. Financial performance is the dependent variable that is divided into accounting and market measures. The proxy for accounting measure is return on asset and proxy for market measure is Tobin’s Q. This study employs univariate and balanced panel data analysis. For robustness of the analysis random-effects GLS regression is carried out. The empirical results show that that Family Firms outperform Non-Family Firms both in terms of accounting and market measures. In the later part family CEOs firms outperform the firms that have either insider or outsider non-family CEOs. This superior performance is subjected to the positive and statistically significant association between family ownership, management, and financial performance.
Dastgeer, Ghulam,Khan, Muhammad Farooq,Nazir, Ghazanfar,Afzal, Amir Muhammad,Aftab, Sikandar,Naqvi, Bilal Abbas,Cha, Janghwan,Min, Kyung-Ah,Jamil, Yasir,Jung, Jongwan,Hong, Suklyun,Eom, Jonghwa American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.15
<P>Heterostructures comprising two-dimensional (2D) semiconductors fabricated by individual stacking exhibit interesting characteristics owing to their 2D nature and atomically sharp interface. As an emerging 2D material, black phosphorus (BP) nanosheets have drawn much attention because of their small band gap semiconductor characteristics along with high mobility. Stacking structures composed of p-type BP and n-type transition metal dichalcogenides can produce an atomically sharp interface with van der Waals interaction which leads to p-n diode functionality. In this study, for the first time, we fabricated a heterojunction p-n diode composed of BP and WS<SUB>2</SUB>. The rectification effects are examined for monolayer, bilayer, trilayer, and multilayer WS<SUB>2</SUB> flakes in our BP/WS<SUB>2</SUB> van der Waals heterojunction diodes and also verified by density function theory calculations. We report superior functionalities as compared to other van der Waals heterojunction, such as efficient gate-dependent static rectification of 2.6 × 10<SUP>4</SUP>, temperature dependence, thickness dependence of rectification, and ideality factor of the device. The temperature dependence of Zener breakdown voltage and avalanche breakdown voltage were analyzed in the same device. Additionally, superior optoelectronic characteristics such as photoresponsivity of 500 mA/W and external quantum efficiency of 103% are achieved in the BP/WS<SUB>2</SUB> van der Waals p-n diode, which is unprecedented for BP/transition metal dichalcogenides heterostructures. The BP/WS<SUB>2</SUB> van der Waals p-n diodes have a profound potential to fabricate rectifiers, solar cells, and photovoltaic diodes in 2D semiconductor electronics and optoelectronics.</P> [FIG OMISSION]</BR>