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Search Results: 1 - 10 of 325428 matches for " Ziyad S. Haidar "
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Bio-Inspired/-Functional Colloidal Core-Shell Polymeric-Based NanoSystems: Technology Promise in Tissue Engineering, Bioimaging and NanoMedicine
Ziyad S. Haidar
Polymers , 2010, DOI: 10.3390/polym2030323
Abstract: Modern breakthroughs in the fields of proteomics and DNA micro-arrays have widened the horizons of nanotechnology for applications with peptides and nucleic acids. Hence, biomimetic interest in the study and formulation of nanoscaled bio-structures, -materials, -devices and -therapeutic agent delivery vehicles has been recently increasing. Many of the currently–investigated functionalized bio-nanosystems draw their inspiration from naturally-occurring phenomenon, prompting the integration of molecular signals and mimicking natural processes, at the cell, tissue and organ levels. Technologically, the ability to obtain spherical nanostructures exhibiting combinations of several properties that neither individual material possesses on its own renders colloidal core-shell architectured nanosystems particularly attractive. The three main developments presently foreseen in the nanomedicine sub-arena of nanobiotechnology are: sensorization (biosensors/ biodetection), diagnosis (biomarkers/bioimaging) and drug, protein or gene delivery (systemic vs. localized/targeted controlled–release systems). Advances in bio-applications such as cell-labelling/cell membrane modelling, agent delivery and targeting, tissue engineering, organ regeneration, nanoncology and immunoassay strategies, along the major limitations and potential future and advances are highlighted in this review. Herein, is an attempt to address some of the most recent works focusing on bio-inspired and -functional polymeric-based core-shell nanoparticulate systems aimed for agent delivery. It is founded, mostly, on specialized research and review articles that have emerged during the last ten years.
A Novel Self-Assembled Liposome-Based Polymeric Hydrogel for Cranio-Maxillofacial Applications: Preliminary Findings
Victor Joo,Thiruganesh Ramasamy,Ziyad S. Haidar
Polymers , 2011, DOI: 10.3390/polym3020967
Abstract: Soft nanogels are submicron-sized hydrophilic structures engineered from biocompatible polymers possessing the characteristics of nanoparticles as well as hydrogels, with a wide array of potential applications in biotechnology and biomedicine, namely, drug and protein delivery. In this work, nanogels were obtained using the physical self-assembly technique or ‘layer-by-layer’ which is based on electrostatic interactions. Liposomal vesicles were coated with alternating layers of hyaluronic acid and chitosan yielding a more viscous hydrogel formulation that previously reported core-shell nanoparticulate suspension, via simply modifying the physico-chemical characteristics of the system. Structural features, size, surface charge, stability and swelling characteristics of the nanogel were studied using scanning electron microscopy and dynamic light scattering. With a specific cranio-maxillofacial application in mind, the hydrogel was loaded with recombinant human (rh) bone morphogenetic protein-7, also known as osteogenic protein-1 or rhOP-1 and release was monitored over an extended period of 60 days. This preliminary study reports promising results on the formulation of a novel core-shell polymeric nanogel.
Modulating the Release Kinetics of Paclitaxel from Membrane-Covered Stents Using Different Loading Strategies
Georg Sydow-Plum,Ziyad S. Haidar,Yahye Merhi,Maryam Tabrizian
Materials , 2008, DOI: 10.3390/ma1010025
Abstract: Membrane-covered Express2TM Monorail? stents composed of chitosan (CH) blended with polyethylene oxide (PEO) in 70:30% wt (CH-PEO) were coated with a monolayer of hyaluronic acid (HA). This significantly improved the resistance to platelet adhesion and demonstrated excellent mechanical properties, resisting the harsh conditions during stent crimping and subsequent inflation. CH-PEO/HA membrane was then combined with a paclitaxel (Pac) delivery system via three different approaches for comparison of release profiles of Pac. The activity of Pac in these systems was confirmed since its presence in the membrane significantly decreased cell viability of U937 macrophages. Presented results are promising for applications requiring different release patterns of hydrophobic drugs.
Video Macrosegmentation Using Automatic Analysis of Similarity Matrices
S. Haidar,B. Chebaro,B. Haidar
Information Technology Journal , 2010,
Abstract: In the present study, we propose an automatic method for segmenting video material using the comparison matrix. Without a priori information, neither any training phase, the similarity matrices are filtered then regional minimums and maximums are extracted over the line and column projections. Pseudo-homogeneous areas are identified between each pair of regional minimums. The pseudo-homogeneous areas in the resulting matrix are thus the macro-segment video records in question. We experiment our method over a database of short video commercials to illustrate the potential of our approach. An overall evaluation is finally established and given.
Applicability of the theory of planned behavior in predicting intended use of Voluntary HIV Counseling and Testing services among teachers of Harari Region, Ethiopia
S Omer, J Haidar
Ethiopian Journal of Health Development , 2010,
Abstract: Background: The predictive validity and applicability of Theory of Planned Behavior (TPB) may be a promising model for understanding and predicting intended behaviors to use VCT services. The need for theory based study would thus be essential in designing evidence based HIV-related interventions in the future. Objectives: To examine the applicability of the Theory of Planned Behavior and the additional predictive role of perceived risk in predicting intended use of Voluntary HIV Counseling and Testing (VCT) services. Methods: A cross sectional study design was conducted among 20 randomly selected schools in Harari Region between March and April 2009. Four hundred ninety seven randomly selected teachers consented to participate in the study giving a response rate of 87.8%. Self administered questionnaire, adopted from the TPB was used for data collection. Multiple linear regression models were used to predict the role of important variables that can influence the intention to use VCT among teachers using SPSS version 15. Result: More than half (53.7%) who had never used VCT service were considered in the analysis for the intended VCT service use. All the modal variables correlated significantly with behavioral intention. Subjective norm (r=0.45, p<0.001), perceived behavioral control (r=0.42, p<0.001) attitude (r=0.33, p<0.001) and perceived susceptibility(r=0.25, p<0.001), were significantly and positively correlated while perceived severity to the illness (r= -0.14, P<0.001) was significantly but negatively correlated with behavioral intention. Perceived severity of the illness, normative belief and having high level of self control were the major predictors for intended use of VCT. Conclusion: The study demonstrated that the TBP is a useful model for evidence based educational programs focusing mainly on creating supportive social system and strengthens their self efficacy for positive VCT uptake. [Ethiop. J. Health Dev. 2010;24(2):96-102]
VCT uptake and associated factors among teachers from Harari Administrative Region
S Omer, J Haidar
Ethiopian Journal of Health Development , 2009,
Abstract: sector which is vital to the creation of human capital is also equally affected. The loss of skilled and experienced teachers due to the problem is increasingly compromising the provision of quality education in most African countries and thus, needs appropriate intervention measures that reverse the current trend. Objectives: To assess the prevalence and determining factors of VCT uptake among teachers of Harari Administrative Region. Methods: A cross sectional study design with analytic component was conducted among 566 teachers drawn from 20 randomly selected schools of Harari Administrative Region from March to April 2009. Self administered questionnaire, adapted from previous relevant studies was used to estimate the prevalence of VCT uptake and the various socio-demographic and psychological factors. Data were entered and analyzed using bi-variate and multivariate models. Results: A total number of 497 teachers responded to the questionnaire adequately making the response rate of 87.8%. The mean age of the participants was 34.68 ranging from 18 – 61 years. There were more teachers from urban areas (72.0%) and most of them were males (62.2%). About half (54.1%) were married and few (5.2%) were divorced. The vast majority (98.6%) heard about the confidential VCT service and their major sources of information were mass media (85.3%) and health workers (56.2%). The prevalence of VCT uptake was 46.3%. The odds of utilizing VCT significantly increased with being younger age group, female and first and second cycle teachers’ category. Conclusions: The major factors identified for increased uptake of VCT are gender, age and salary category. Actions targeting the males, non-youth age group and low grade teachers’ are necessary to follow their peer groups to utilize the VCT service in order to achieve the goal of education set for 2015.
Venn Diagram Approach to Heisenberg Inequalities
Nassar H. S. Haidar
Applied Physics Research , 2012, DOI: 10.5539/apr.v4n2p253
Abstract: We report on a proof to the Heisenberg inequalities, for both vector-like and scalar-like variables, that is based on statistical dependence of quantum events on appropriate Venn diagrams. A similar proof is provided for the “energy-velocity” uncertainty principle of Haidar (2010).
Inversion of Fourier Transforms by Means of Scale-Frequency Series
Nassar H. S. Haidar
International Journal of Engineering Mathematics , 2014, DOI: 10.1155/2014/686785
Abstract: We report on inversion of the Fourier transform when the frequency variable can be scaled in a variety of different ways that improve the resolution of certain parts of the frequency domain. The corresponding inverse Fourier transform is shown to exist in the form of two dual scale-frequency series. Upon discretization of the continuous scale factor, this Fourier transform series inverse becomes a certain nonharmonic double series, a discretized scale-frequency (DSF) series. The DSF series is also demonstrated, theoretically and practically, to be rate-optimizable with respect to its two free parameters, when it satisfies, as an entropy maximizer, a pertaining recursive nonlinear programming problem incorporating the entropy-based uncertainty principle. 1. Introduction We revisit the classical problem of recovering a Fourier transformable signal in , , from its Fourier transform; see, for example, [1, 2], image . The space is the set of all real functions for which the integral exists. Obviously, the function to be integrated in (1) is the product and when the variable , the function will oscillate extremely rapidly. Then in order to follow the variations of the product meaningfully in a -quadrature formula, see, for example, [3], for (1), there is a need for a large number of -points, even for slowly varying . Consequently, the faster the decreases as , the more the tractable computationally the integral (1) will be, and the more accurate are its numerical evaluations. Bandlimiting of signals has been a practical way for easing the previous problem. A fact that has so far been motivating the wide engineering interest in bandlimited signals, for which where is the band width of with an image having the compact support of . Inversion of bandlimited signals is currently performed by projections onto convex sets (POCS) algorithms [4], which encompass the Gerchberg-Papoulis algorithm [5]. In this work we report on a novel robust semianalytical method for integration of (1) to recover a signal that is not necessarily bandlimited. In this method, the frequency variable can be scaled in a variety of different ways that improve the resolution of certain parts of the frequency domain. The corresponding inverse Fourier transform is shown to exist in the form of two dual scale-frequency series. Upon discretization of the continuous scale factor, this Fourier transform series inverse becomes a certain nonharmonic [6] double series, a discretized scale-frequency (DSF) series. This DSF series is demonstrated, for the first time in this work, to be the proper
Elbow dislocation associated with vascular injury treated by delayed vascular repair
S. Joshy,S. G. Haidar
Journal of Orthopaedics and Traumatology , 2005, DOI: 10.1007/s10195-005-0109-2
Abstract: Vascular injuries associated with elbow dislocation are generally treated by urgent surgical repair. Delayed vascular repair or non-operative treatment is an option if there are adequate signs of perfusion in the absence of palpable pulses. We report a case of elbow dislocation with brachial artery rupture, treated by delayed vascular repair.
Path Coefficient Analysis of Some Yield Traits in Cotton (Gossypium hirsutum L.)
S. Haidar,M. A. Khan
Pakistan Journal of Biological Sciences , 1998,
Abstract: Path coefficient analysis was done to understand the type of contribution directly as well as indirectly of each character to yield of seed cotton. The results revealed that number of bolls per plant and boll weight had the maximum direct effect on yield of seed cotton per plant. Number of bolls per plant had negative indirect effect on boll weight, while boll weight had positive indirect effect on ginning outturn percentage and negative indirect effect on number of bolls per plant and number of seeds per boll. Number of seeds per boll had negative direct effect on yield of seed cotton per plant while ginning outturn percentage had very small positive effect on yield of seed cotton per plant. So it is suggested that selection for higher productivity should be based on higher number of bolls per plant and boll weight.
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