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Search Results: 1 - 10 of 341748 matches for " Ayesha S. Ali "
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Markov Equivalence Classes for Maximal Ancestral Graphs
Ayesha R. Ali,Thomas S. Richardson
Computer Science , 2012,
Abstract: Ancestral graphs are a class of graphs that encode conditional independence relations arising in DAG models with latent and selection variables, corresponding to marginalization and conditioning. However, for any ancestral graph, there may be several other graphs to which it is Markov equivalent. We introduce a simple representation of a Markov equivalence class of ancestral graphs, thereby facilitating model search. \ More specifically, we define a join operation on ancestral graphs which will associate a unique graph with a Markov equivalence class. We also extend the separation criterion for ancestral graphs (which is an extension of d-separation) and provide a proof of the pairwise Markov property for joined ancestral graphs.
Markov equivalence for ancestral graphs
R. Ayesha Ali,Thomas S. Richardson,Peter Spirtes
Statistics , 2009, DOI: 10.1214/08-AOS626
Abstract: Ancestral graphs can encode conditional independence relations that arise in directed acyclic graph (DAG) models with latent and selection variables. However, for any ancestral graph, there may be several other graphs to which it is Markov equivalent. We state and prove conditions under which two maximal ancestral graphs are Markov equivalent to each other, thereby extending analogous results for DAGs given by other authors. These conditions lead to an algorithm for determining Markov equivalence that runs in time that is polynomial in the number of vertices in the graph.
Microbial Tyrosinases: Promising Enzymes for Pharmaceutical, Food Bioprocessing, and Environmental Industry
Kamal Uddin Zaidi, Ayesha S. Ali, Sharique A. Ali, Ishrat Naaz
Biochemistry Research International , 2014, DOI: 10.1155/2014/854687
Abstract: Tyrosinase is a natural enzyme and is often purified to only a low degree and it is involved in a variety of functions which mainly catalyse the o-hydroxylation of monophenols into their corresponding o-diphenols and the oxidation of o-diphenols to o-quinones using molecular oxygen, which then polymerizes to form brown or black pigments. The synthesis of o-diphenols is a potentially valuable catalytic ability and thus tyrosinase has attracted a lot of attention with respect to industrial applications. In environmental technology it is used for the detoxification of phenol-containing wastewaters and contaminated soils, as biosensors for phenol monitoring, and for the production of L-DOPA in pharmaceutical industries, and is also used in cosmetic and food industries as important catalytic enzyme. Melanin pigment synthesized by tyrosinase has found applications for protection against radiation cation exchangers, drug carriers, antioxidants, antiviral agents, or immunogen. The recombinant V. spinosum tryosinase protein can be used to produce tailor-made melanin and other polyphenolic materials using various phenols and catechols as starting materials. This review compiles the recent data on biochemical and molecular properties of microbial tyrosinases, underlining their importance in the industrial use of these enzymes. After that, their most promising applications in pharmaceutical, food processing, and environmental fields are presented.
Evaluation of Tyrosinase Producing Endophytic Fungi from Calotropis gigantea, Azadirachta indica, Ocimum tenuiflorum and Lantana camara
Kamal Uddin Zaidi, Abin Mani, Ayesha S. Ali, Sharique A. Ali
Annual Review & Research in Biology , DOI: www.sciencedomain.org
Abstract: Aims: The present study focuses on evaluation of tyrosinase producing endophytic fungi from Calotropis gigantea, Azadirachta indica, Ocimum tenuiflorum and Lantana camara. Place and Duration of the Study: The present study was conducted at centre for Scientific Research and Development People’s Group Bhanpur, Bhopal India during January 2011 to December 2012. Methodology: The endophytic fungi were isolated from leaves, root and stem of Calotropis gigantea, Azadirchta Indica, Ocimum tenuifloram and Lantana camara and cultured on malt extract agar. Isolates were evaluated for tyrosinase production qualitatively and quantitatively on modified Czapex Dox’s agar. Results: Out of fifty isolates, twenty seven isolates showed tyrosinase production in agar plate assay. It was observed that endophytes isolated from Azadirachta indica and Ocimum tenuiflorum has higher production of extracellular tyrosinase in comparison with Calotropis gigantea and Lantana camara. Conclusion: Phylum basidiomycete is considered to be the prominent source of tyrosinase. This finding indicates that the endophytic fungi are also a promising source and are more suitable for large scale productions. - See more at: http://www.sciencedomain.org/abstract.php?iid=239&id=9&aid=1461#.U-Mmr1OJtNk
Towards Characterizing Markov Equivalence Classes for Directed Acyclic Graphs with Latent Variables
Ayesha R. Ali,Thomas S. Richardson,Peter L. Spirtes,Jiji Zhang
Computer Science , 2012,
Abstract: It is well known that there may be many causal explanations that are consistent with a given set of data. Recent work has been done to represent the common aspects of these explanations into one representation. In this paper, we address what is less well known: how do the relationships common to every causal explanation among the observed variables of some DAG process change in the presence of latent variables? Ancestral graphs provide a class of graphs that can encode conditional independence relations that arise in DAG models with latent and selection variables. In this paper we present a set of orientation rules that construct the Markov equivalence class representative for ancestral graphs, given a member of the equivalence class. These rules are sound and complete. We also show that when the equivalence class includes a DAG, the equivalence class representative is the essential graph for the said DAG
Prevalence and Risk of Anemia in Type-2 Diabetic Patients  [PDF]
Ayesha Sharif, Shahnila Younus, Kanwal Baig, Nafisa Hassan Ali
Health (Health) , 2014, DOI: 10.4236/health.2014.612173
Abstract: Aim: To determine the prevalence and risk of anemia in type-2 diabetes mellitus. In addition, the incidence and risk of anemia in these patients were assessed according to gender and glycemic control status. Methods: The study group comprised 200 patients with type-2 diabetes. Patients were divided into groups according to glycemic control and gender. Glycated hemoglobin (HbA1c), blood glucose level, hemoglobin concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) of subjects were evaluated. The presence of anemia was defined by a hemoglobin level <13.0 g/dl for men and <12.0 g/dl for women. The patients were considered as diabetic if he/she had glycated hemoglobin >6.5%, fasting blood glucose >126 mg/dl and random blood glucose >200 mg/dl. Result: 63% of diabetic patients had anemia. There was higher incidence and risk of anemia in females (36%) as compared to males (27%) (p < 0.05) and in poorly controlled diabetes HbA1C >7.5% (49.5%) compared to those with controlled diabetes HbA1C < 7.5% (13.5%) (p < 0.05). Conclusion: This study indicated that poor glycemic control and gender difference are associated with the incidence of anemia in type II diabetes. Our findings suggest the need of screening for anemia in diabetes out-patient clinics. Routine hematological tests along with blood glucose level should be mandatory in order to make therapeutic decisions for the treatment of anemia in type II diabetes mellitus.
Activity Based Quality Model for Evaluating Web2.0 Applications
Ambreen Nazir,Ayesha Raana,Ali Javed
International Journal of Modern Education and Computer Science , 2013, DOI: 10.5815/ijmecs.2013.03.02
Abstract: Quality is key term to be considered when developing the Web applications. If this is not adequately measured; there will be little to force users to use web applications. The focus of Web2.0 is to enhance the interactions between the application and end users and among users. The main challenge of this research is to identify the key quality attributes that gain the end user attention towards the Web applications. There are many Quality Models available for measuring the W2A (Web2.0 Applications). This paper has a critical review of the previously defined quality models. It defines a theoretical quality model containing essential attributes to assess the quality of W2A.
DNA Extraction from Insects by Using Different Techniques: A Review  [PDF]
Usman Asghar, Muhammad Faheem Malik, Fakhra Anwar, Ayesha Javed, Ali Raza
Advances in Entomology (AE) , 2015, DOI: 10.4236/ae.2015.34016
Abstract: This review paper was prepared at Department of Zoology, University of Gujrat, Pakistan during 2014-2015. The data for the two decades, DNA Extraction from Insects by Using Different Techniques was compiled through a thorough review of many research articles published in various journals of international repute. Insects are very important economically and ecologically for human due to their various roles, as pests, decomposer in nutrition cycle, vector for the transmission of certain diseases and a source of medically and economically important products. To identify insect, and for research on their role, different molecular techniques are used. For each molecular technique, high quality DNA is required, which is extracted from the insects by different techniques. The selection of DNA extraction technique is depended upon specimen under study, time required for extraction, economical stander of technique due to reagents and equipment used for extraction and most importantly extracted DNA quality. In this paper, most frequently used techniques for DNA extraction from insect with different size and condition are outlined. This paper is only a guide for these techniques and we describe them briefly.
Use of Polymerase Chain Reaction for Identification of the Pathogen and Management of Potato Soft Rot with Zinc Application  [PDF]
Ayesha Bibi, Muhammad Junaid, Musharaf Ahmad, Amjad Ali, Fazli Wahid, Rubina Naz, Arif Ullah, Amanullah Mahar, Shahmir Ali Kalhoro
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.68118
Abstract: Effect of different Zinc doses was investigated against Erwinia carotovora ssp. atroseptica, the potato blackleg/soft rot causing organism, during 2009 and 2010 in Department of Plant Pathology and Institute of Biotechnology and Genetic Engineering, The University of Agriculture, Peshawar-Pakistan. Out of 200 tested samples, 21 of them were proved to be Eca. However, these tentative Eca isolates showed some characteristics which were unexpected for Eca. We, therefore, decided to perform Polymerase Chain Reaction using Eca-specific primers, Eca1F and Eca2R for confirm identification. For disease management, at the time of sowing, pots containing 5 kg sterilized soil were applied with Zinc in four different treatments i.e. 8 mg, 10 mg, 12 mg and 14 mg along with one control. Results indicated that 12 mg (4.8 kg Zn ha-1) were better doses in controlling the disease up to 73% and increasing the yield up to 117% as compared to control plants.
Study of Cultural Conditions for the Conversion of L-tyrosine to L-dopa by the Strain of Aspergillus oryzae Isb-9
Ayesha Khan,Sikander Ali,Ikram-ul-Haq
Journal of Food Technology , 2013,
Abstract: The present study is concerned with the optimization of cultural conditions for maximum conversion of L-Tyrosine to L-DOPA by strain of Aspergillus oryzae ISB-9. The effect of time course, temperature and pH on the production of L-DOPA was checked. Surface culture method was employed for L-DOPA fermentation. Optimum temperature and time for L-DOPA production is 50 C and 60 minutes respectively. However, the optimum pH of mycelium development was 5.0 because maximum production of L-DOPA (0.95 mg ml-1) was observed at this pH. The acidic pH (3.0) of reaction mixture was found to be optimum for higher L-DOPA production (1.1mg ml-1).
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