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Search Results: 1 - 10 of 403163 matches for " Katherine M. Hannan "
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Relative Expression Levels Rather Than Specific Activity Plays the Major Role in Determining In Vivo AKT Isoform Substrate Specificity
Rachel S. Lee,Colin M. House,Briony E. Cristiano,Ross D. Hannan,Richard B. Pearson,Katherine M. Hannan
Enzyme Research , 2011, DOI: 10.4061/2011/720985
Abstract: The AKT protooncogene mediates many cellular processes involved in normal development and disease states such as cancer. The three structurally similar isoforms: AKT1, AKT2, and AKT3 exhibit both functional redundancy and isoform-specific functions; however the basis for their differential signalling remains unclear. Here we show that in vitro, purified AKT3 is ~47-fold more active than AKT1 at phosphorylating peptide and protein substrates. Despite these marked variations in specific activity between the individual isoforms, a comprehensive analysis of phosphorylation of validated AKT substrates indicated only subtle differences in signalling via individual isoforms in vivo. Therefore, we hypothesise, at least in this model system, that relative tissue/cellular abundance, rather than specific activity, plays the dominant role in determining AKT substrate specificity in situ. 1. Introduction The AKT protooncogene comprises a family of three highly homologous serine/threonine kinases (AKT1, 2 and 3) [1], that play major regulatory roles in a wide range of cellular processes including cell survival, growth, proliferation, angiogenesis, and metabolism [2–4]. These processes are key to normal development and often dysregulated in disease. Consistent with these wide-ranging roles, to date, more than 100 AKT substrates have been identified that are integral in the regulation of one or more of these cellular processes [3]. Each AKT isoform consists of a pleckstrin homology domain (>75% identity), a linker region (>17% identity), a kinase domain (>87% identity), and a carboxyl tail with a hydrophobic motif (>66% identity) [1]. The two key regulatory phosphorylation sites on AKT are also conserved, Ser473 and Thr308 in AKT1, Ser474 and Thr308 in AKT2, and Ser472 and Thr305 in AKT3 [5]. Thr308 is phosphorylated by 3-Phosphoinositide-dependent kinase 1 (PDK1) and Ser473 by mammalian target of rapamycin (mTOR) complex 2 (mTORC2) [6–9]. Recent studies have suggested that phosphorylation at Ser473 dictates AKT signaling to a specific set of substrates, and phosphorylation at Thr308 determines the kinase activity [8, 10]. Whilst all three AKT isoforms share a high sequence identity and exhibit functional redundancy, there is also genetic evidence that they can function distinctly. This is illustrated in the distinct phenotypes exhibited by the single isoform knockout (KO) mice and the severe phenotypes exhibited by double KO (dKO) mice. AKT1?/? mice are not 100% viable, with surviving mice that reach adulthood being 15–20% smaller than their wild type (wt) and
Autophagy Induction Is a Tor- and Tp53-Independent Cell Survival Response in a Zebrafish Model of Disrupted Ribosome Biogenesis
Yeliz Boglev,Andrew P. Badrock,Andrew J. Trotter,Qian Du,Elsbeth J. Richardson,Adam C. Parslow,Sebastian J. Markmiller,Nathan E. Hall,Tanya A. de Jong-Curtain,Annie Y. Ng,Heather Verkade,Elke A. Ober,Holly A. Field,Donghun Shin,Chong H. Shin,Katherine M. Hannan,Ross D. Hannan,Richard B. Pearson,Seok-Hyung Kim,Kevin C. Ess,Graham J. Lieschke,Didier Y. R. Stainier,Joan K. Heath
PLOS Genetics , 2013, DOI: 10.1371/journal.pgen.1003279
Abstract: Ribosome biogenesis underpins cell growth and division. Disruptions in ribosome biogenesis and translation initiation are deleterious to development and underlie a spectrum of diseases known collectively as ribosomopathies. Here, we describe a novel zebrafish mutant, titania (ttis450), which harbours a recessive lethal mutation in pwp2h, a gene encoding a protein component of the small subunit processome. The biochemical impacts of this lesion are decreased production of mature 18S rRNA molecules, activation of Tp53, and impaired ribosome biogenesis. In ttis450, the growth of the endodermal organs, eyes, brain, and craniofacial structures is severely arrested and autophagy is up-regulated, allowing intestinal epithelial cells to evade cell death. Inhibiting autophagy in ttis450 larvae markedly reduces their lifespan. Somewhat surprisingly, autophagy induction in ttis450 larvae is independent of the state of the Tor pathway and proceeds unabated in Tp53-mutant larvae. These data demonstrate that autophagy is a survival mechanism invoked in response to ribosomal stress. This response may be of relevance to therapeutic strategies aimed at killing cancer cells by targeting ribosome biogenesis. In certain contexts, these treatments may promote autophagy and contribute to cancer cells evading cell death.
A Novel Approach of Dyeing Jute Fiber with Reactive Dye after Treating with Chitosan  [PDF]
M. A. Rahman Bhuiyan, Abu Shaid, M. M. Bashar, P. Haque, M. A. Hannan
Open Journal of Organic Polymer Materials (OJOPM) , 2013, DOI: 10.4236/ojopm.2013.34014
Abstract:

Jute is generally not dyed with reactive dye though it is a cellulosic fiber. Reactive dye is extensively used to dye cotton, viscose and other cellulosic fibers whereas jute is dyed with basic dye. This paper presents a novel approach to dye the jute fiber with reactive dye after treating with chitosan. Jute fabric was treated with chitosan solution at different con- centrations (0.5%, 1%, 2%, 3% and 4%) and then dyed with reactive dye. The depth and fastness of shade of dyed fabric were analyzed by comparing the chitosan treated samples with untreated dyed fabric samples. It has been found that, the dyebath exhaustion is increased with the increment of chitosan concentrations. The exhaustion percentages have found 36.79%, 41.59%, 48.33%, 54.46% and 58.75% for the fabric treated with 0.5%, 1%, 2%, 3% and 4% chitosan solution respectively, while the exhaustion of dyebath is only 23.15% for untreated fabric. The K/S values (at λmax = 540 nm) of dyed samples have found 4.93, 6.77, 10.5, 14.07, 15.57 and 2.37 for 0.5%, 1%, 2%, 3%, 4% and untreated fabric respectively. The color fastness to washing and rubbing of the dyed fabrics was also evaluated. In case of dry rubbing, both types of fabric have shown almost similar fastness ratings. However, chitosan treated fabrics have shown inferior fastness rating in case of wet rubbing and washing, particularly for the fabrics at higher chitosan concentrations.

Dynamic Phasor Modeling and EMT Simulation of USSC
M A Hannan,A Mohamed,A Hussain
Lecture Notes in Engineering and Computer Science , 2009,
Abstract:
Intelligent Photovoltaic Maximum Power Point Tracking Controller for Energy Enhancement in Renewable Energy System
Subiyanto,Azah Mohamed,M. A. Hannan
Journal of Renewable Energy , 2013, DOI: 10.1155/2013/901962
Abstract:
Intelligent Photovoltaic Maximum Power Point Tracking Controller for Energy Enhancement in Renewable Energy System
Subiyanto,Azah Mohamed,M. A. Hannan
Journal of Renewable Energy , 2013, DOI: 10.1155/2013/901962
Abstract: Photovoltaic (PV) system is one of the promising renewable energy technologies. Although the energy conversion efficiency of the system is still low, but it has the advantage that the operating cost is free, very low maintenance and pollution-free. Maximum power point tracking (MPPT) is a significant part of PV systems. This paper presents a novel intelligent MPPT controller for PV systems. For the MPPT algorithm, an optimized fuzzy logic controller (FLC) using the Hopfield neural network is proposed. It utilizes an automatically tuned FLC membership function instead of the trial-and-error approach. The MPPT algorithm is implemented in a new variant of coupled inductor soft switching boost converter with high voltage gain to increase the converter output from the PV panel. The applied switching technique, which includes passive and active regenerative snubber circuits, reduces the insulated gate bipolar transistor switching losses. The proposed MPPT algorithm is implemented using the dSPACE DS1104 platform software on a DS1104 board controller. The prototype MPPT controller is tested using an agilent solar array simulator together with a 3?kW real PV panel. Experimental test results show that the proposed boost converter produces higher output voltages and gives better efficiency (90%) than the conventional boost converter with an RCD snubber, which gives 81% efficiency. The prototype MPPT controller is also found to be capable of tracking power from the 3?kW PV array about 2.4 times more than that without using the MPPT controller. 1. Introduction Energy generation based on renewable energy resources has received a great attention. Photovoltaic (PV) system is one of the promising renewable energy technologies. The photovoltaic (PV) generation system is a promising renewable, clean, and environmentally friendly source of energy [1]. Each solar cell produces only about one-half volt of electricity, and dozens of individual solar cells are interconnected in a sealed, weatherproof package called a PV module [2]. PV modules can be connected in series, parallel, or both into what is called a PV array. This PV array is connected to a power conditioner and then to a load or grid tie as a grid connected PV system. In general, the two main problems with PV power generation systems are the low conversion efficiency and that electrical power generated by a typical PV panel varies with weather conditions. Thus, many studies on enhancing the energy-generation efficiency of PV applications have been carried out [3]. A PV generation system should operate at its
Familial correlates of adolescent girls' physical activity, television use, dietary intake, weight, and body composition
Katherine W Bauer, Dianne Neumark-Sztainer, Jayne A Fulkerson, Peter J Hannan, Mary Story
International Journal of Behavioral Nutrition and Physical Activity , 2011, DOI: 10.1186/1479-5868-8-25
Abstract: Subjects included girls (mean age = 15.7), 71% of whom identified as a racial/ethnic minority, and one of their parents (dyad n = 253). Parents completed surveys assessing factors in the family environment including familial support for adolescents' PA, healthful dietary intake, and limiting TV use; parental modeling of behavior; and resources in the home such as availability of healthful food. Girls' PA and TV use were measured by 3-Day Physical Activity Recall (3DPAR) and dietary intake by survey measures. BMI was measured by study staff, and body fat by dual-energy X-ray absorptiometry (DXA). Hierarchical linear regression models tested individual and mutually-adjusted relationships between family environment factors and girls' outcomes.In the individual models, positive associations were observed between family support for PA and girls' total PA (p = .011) and moderate-to-vigorous PA (p=.016), home food availability and girls' soft drink (p < .001) and FV (p < .001) intake, and family meal frequency and girls' FV intake (p = .023). Across the individual and mutually-adjusted models, parental modeling of PA, TV, and soft drink and FV intake was consistently associated with girls' behavior.Helping parents improve their physical activity and dietary intake, as well as reduce time watching television, may be an effective way to promote healthful behaviors and weight among adolescent girls.One-third of adolescent girls in the United States are overweight or obese [1]. This high prevalence of overweight and obesity among adolescent girls, and specifically African American, Hispanic, and girls from low socioeconomic (SES) families [1,2], may be attributable to girls' participation in behaviors associated with higher weight and excess weight gain including lack of regular physical activity [3], frequent sedentary behavior including watching television [4], and poor dietary intake including frequent consumption of sugar-sweetened soft drinks [5] and less than adequate in
Patellar Tendinopathy: A Physiotherapist’s Perspective  [PDF]
Hannan Mohammad Ali
International Journal of Clinical Medicine (IJCM) , 2012, DOI: 10.4236/ijcm.2012.32019
Abstract: The pathology of patellar tendinopathy and the mechanisms of pain are poorly understood. The most popular treatment modality is the Eccentric overload Exercise. However, there is insufficient evidence to recommend a specific protocol and yet it is the most commonly used treatment modality. The aim of this case study is to present the possible mechanisms of pain and a treatment approach on a patient who was diagnosed as having patellar tendinopathy. It is suggested that hyper extension of the knee might be the source of patellar tendon pain in this patient. Following a course of pulsed short wave diathermy the patient was symptom free and remained so at 6 month review. Further studies to evaluate effectiveness of pulsed short wave diathermy is suggested.
Intelligent Bus Monitoring and Management System
M. A. HANNAN,A. M. MUSTAPHA,A. HUSSAIN,H. BASRI
Lecture Notes in Engineering and Computer Science , 2012,
Abstract:
Survey on Inter-Vehicle Communication Applications: Current Trends and Challenges
M.S. Javadi,S. Habib,M.A. Hannan
Information Technology Journal , 2013,
Abstract: Inter-Vehicle Communication (IVC) has presented a promising role in vehicular technology to fulfill a variety of applications to improve safety and traffic flow. This article outlines IVC taxonomy, applications and challenges. Current trends of vehicular communication technologies are explained including classification, functions, applications, missions, requirements, advantages and disadvantages, respectively. Many IVC applications have been investigated from the literature to provide safe, comfortable and reliable vehicular operations. In this article, the recent research trends and development activities in inter-vehicle communications have been critically reviewed, emphasizing the areas where further work is needed. It is found that the continuous developing technology will certainly push the future market of high-quality IVC systems. However, the issues and challenges of the existing IVC system such as data aggregation, distribution, hardware/software compatibility, nodes density, security, mobility, market, etc. are highlighted to future system development. Thus, this study will lead the increasing need to develop new and improved IVC technology for many applications.
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