51 research outputs found
Relationship between endothelial cell loss and microcoaxial phacoemulsification parameters in noncomplicated cataract surgery
No full textMohamed AE Soliman Mahdy1,2, Mohamed Z Eid1, Mahmoud Abdel-Badei Mohammed3, Amr Hafez4,5, Jagdish Bhatia21Ophthalmic Department, Al-Hussein University Hospital, Al-Azhar University, Cairo, Egypt; 2Ophthalmic Department, Rustaq Hospital, Rustaq, Sultanate of Oman; 3Research Institute of Ophthalmology, Cairo, Egypt; 4Magrabi Eye and Ear Center, Muscat, Sultanate of Oman; 5Ophthalmic Department, Al-Azhar University Hospital, Assuit, EgyptPurpose: To assess the relationship between postoperative endothelial cell loss and microcoaxial phaco parameters using Ozil IP (Alcon Laboratories, Inc, Fort Worth, TX) in noncomplicated cataract surgery.Methods: In this prospective observational study, 120 consecutive cases of cataract patients with different grades of nuclear hardness underwent microcoaxial phacoemulsification through a 2.2-mm clear corneal incision. An Alcon Infinity Vision System with Ozil IP (Alcon Laboratories) was used with an Ozil torsional handpiece and a Kelman-style 45° phacoemulsification tip. Patients underwent preoperative and postoperative central endothelial cell counts.Results: The study included 120 cases of age-related cataract whose mean age (standard deviation [SD]) was 59.68 years (9.47). There was a highly statistically significant endothelial cell loss (P < 0.001). The endothelial cell loss ranged 11–1149 cells/mm2 with a median (interquartile range) of 386 cells/mm2 (184.5–686 cells/mm2). The percentage of postoperative ECLoss% ranged from 0.48% to 47.8% with a median (interquartile range) of 15.4% (7.2% to 26.8%). A significant positive correlation was found between the ECLoss% and different phaco parameters. The Spearman’s rank-order correlation coefficient values, rho, (ρ) were as follows: CDE (ρ = 0.425), aspiration time (ρ = 0.176), and volume (ρ = 0.278). Also, ECLoss% was significantly correlated with the grade of nuclear opalescence (Kendall’s tau τ = 0.42).Conclusion: Microcoaxial phacoemulsification was efficient in removing noncomplicated cataracts; however a statistically significant endothelial cell loss was noted, especially with increased nuclear hardness. This endothelial cell loss was mostly related to the increased cumulative dissipated energy (CDE), aspiration time, and volume of balanced salt solution used.Keywords: cataract surgery, phacoemulsification, Ozil, endothelial cells, cumulative dissipated energy&nbsp
Biomedical applications of amino acid-modified chitosans: A review
No full textThe presence of reactive primary amines in the backbone structure of chitosan, enables the derivatisation with different functional groups and thereby improving and expanding its properties, such as solubility and mucoadhesiveness, for biomedical applications. Such derivatives can be exploited with good results in a number of biomedical areas, including enhancement of nucleic acid transfection in gene therapy, as well as many other applications aiming to maximize drug delivery and aiding tissue engineering. The aim of this review is to provide an up to date overview of the methods used for derivatizing the chitosan with amino acids and to discuss the characteristics and potential biomedical application of the different amino acid derivatized chitosans described in the literature. © 2012 Elsevier Ltd.link_to_subscribed_fulltex
A technique for estimating permeability of a randomly fractured rock mass
No full textExtensive field and laboratory testing programs were performed to develop a relationship between the permeability of a fractured limestone and the core recovery values. The studied limestone does not encompass any jointing system but is consistently and randomly fractured. Nineteen in situ falling head permeability tests were carried out to measure permeability of the fractured rock mass at a representative study area. Analysis of test results has led to the formulation of an empirical equation that estimates the permeability of the rock mass in terms of its solid core recovery value and the permeability of the fractures filling material. Unlike the existing equations for estimating the permeability of rock masses, the proposed equation is simple and utilizes parameters that can be easily determined in regular geotechnical field and laboratory investigations. A technique is also presented to estimate the permeability of a rock layer, the quality of which significantly changes with depth, using the proposed equation that utilizes a single value of core recovery. Analysis of well-documented pumping test results supported the validity of the proposed equation and technique.Acknowledgments The work described in this paper forms part of an applied research project funded by Qatar University. Support from the University in form of research resources is gratefully acknowledged. The author also acknowledges Omar M. Alansari, Abdelrah-man A. Hamad, and Mahmoud A. Alarouqi of Qatar University for their help during the field and laboratory investigation.Scopu
Challenges of Wireline Formation Testing and Fluid Sampling in Tight, Low Permeability Gas Reservoirs: Case Study from Saudi Arabia
No full textAbstract
Saudi Aramco's operations cover a wide range of environments, some of which are multilayer gas reservoirs, consisting of thinly-laminated shaly sands. Evaluations based on conventional log data often prove to be inconclusive. Wireline formation testers are routine sources of reservoir pressure and fluid samples that address uncertainties in these formation evaluations.
In general, low permeability reservoirs pose numerous challenges for obtaining successful pressure measurements and fluid samples, including supercharging effects and "tight" tests, where no pressure measurements or samples can be obtained. In some cases, tight reservoir permeability prevents an adequate and competent mud cake buildup, which can prevent sealing of the conventional rubber probe type pads. In this paper, the authors share the different approaches employed under some of these challenging conditions in getting representative pressures and samples. Proper selection of tool configuration and appropriate pad and packer design were key success factors.
In the paper, we highlight how to use pre-job modeling to improve pressure testing and fluid sampling.. In our examples, pre-job modeling were done to predict the expected rates and drawdowns. We used dual ports within the straddle packer testing interval, which permits the segregation of gas and the filtrate. This allowed the formation fluid to be sampled faster than a single-port packer design or probe type tool. We also demonstrate how a combination of pad type probes and dual packer helped to enhance the success rate and reduced our pumping time during sampling.
This paper reviews cases of testing in tight gas reservoirs. It also demonstrates how we improved the success rate of our pressure testing and sampling by combining modern wireline formation testing (WFT) functionalities and effective pre-job planning. This approach is helping us meet the challenge of obtaining representative pressures and fluid samples in low permeability formations.</jats:p
Long-term outcome of treat and extend intravitreal ziv-aflibercept therapy
Get PDFAim To assess the 30-month outcome of treat and extend (TAE) intravitreal ziv-aflibercept therapy in eyes with macular diseases. Methods In this prospective study, consecutive subjects received intravitreal 0.05 mL ziv-aflibercept (1.25 mg) injections for various macular diseases. Outcome measures were best-corrected visual acuity (BCVA) (logarithm of the minimum angle of resolution) and central macular thickness (CMT) on spectral domain optical coherence tomography. Paired comparison was done using Wilcoxon signed-rank test calculator. Results Fifty-three eyes of 48 subjects (33 naïve eyes) received intravitreal ziv-aflibercept and were followed between 12 and 30 months following TAE included neovascular age-related macular degeneration (nAMD) (35 eyes) and diabetic macular oedema (DMO) (18 eyes). In eyes with nAMD, CMT decreased by 107.8 μm at the 30-month follow-up (p=0.012) with BCVA gain of 0.52 (p=0.001). In eyes with DMO, CMT decreased by 224.3 μm at the 30-month follow-up (p=0.027) with BCVA gain of 0.46 (p=0.042). Combining all disease categories, the mean number of injections was 9.2 at month 12, 2.5 between 12 and 18 months, 1.6 between 18 and 24 months and 1.0 between 24 and 30 months. Conclusions Using TAE regimen, intravitreal ziv-aflibercept appeared efficacious at managing retinal disease through month 30 using the TAE regimen. © Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ
The Influence of Chicken Egg Lysozyme or Zinc-Bacitracin Antibiotic on the Growth Performance, Antibacterial Capacity, Blood Profiles, and Antioxidative Status of Rabbits: A Comparative Study
No full textDietary egg lysozyme has beneficial roles in the growth performance and health conditions of animals. The study was performed using 90 multicolored rabbits in three groups (each replicate with thirty rabbits). In the control group, rabbits were fed a diet without zinc bacitracin (ZnB) or egg lysozyme, while the second and third groups were treated with ZnB and lysozyme additive at 100 mg/kg, respectively. After eight weeks, the final weight and body weight gain (BWG) of rabbits fed dietary egg lysozyme and ZnB additives were meaningfully increased (p p p Clostridium spp. and Escherichia coli (p Lactobacillus and total bacteria were meaningfully increased in the the intestines of rabbits treated with egg lysozyme and ZnB (p p p p SOD1) and glutathione peroxidase (GPX) in the liver of rabbits fed dietary egg lysozyme and ZnB additives were markedly upregulated (p SOD1 and GPX genes than rabbits treated with ZnB (p < 0.05). In conclusion, the inclusion of egg lysozyme could replace the inclusion of ZnB in the diets of rabbits
Nonlinear filtering for state delayed systems with Markovian switching
Get PDFCopyright [2003] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This paper deals with the filtering problem for a general class of nonlinear time-delay systems with Markovian jumping parameters. The nonlinear time-delay stochastic systems may switch from one to the others according to the behavior of a Markov chain. The purpose of the problem addressed is to design a nonlinear full-order filter such that the dynamics of the estimation error is guaranteed to be stochastically exponentially stable in the mean square. Both filter analysis and synthesis problems are investigated. Sufficient conditions are established for the existence of the desired exponential filters, which are expressed in terms of the solutions to a set of linear matrix inequalities (LMIs). The explicit expression of the desired filters is also provided. A simulation example is given to illustrate the design procedures and performances of the proposed method
Highly Pathogenic Avian Influenza Virus (H5N8) Clade 2.3.4.4 Infection in Migratory Birds, Egypt
Get PDFWe isolated highly pathogenic avian influenza virus (H5N8) of clade 2.3.4.4 from the common coot (Fulica atra) in Egypt, documenting its introduction into Africa through migratory birds. This virus has a close genetic relationship with subtype H5N8 viruses circulating in Europe. Enhanced surveillance to detect newly emerging viruses is warranted
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