Repair of the Malpositioned Lower Lid

Complications from surgical approaches to the orbit can be associated with debilitating morbidity and negative surgical outcomes. The surgeon must be familiar with the different factors that predispose a patient to these complications and be facile with techniques to avoid them. In this article, the authors discuss the surgical anatomy of the lower eyelid, as well as various complications that result from eyelid surgery, including lower lid retraction, ectropion, entropion, canthal malposition, and midface descent. They also discuss various management techniques that are employed in addressing these complications

Exploring the complexities of gender roles and psychological wellbeing in farm-families: implications for agricultural extension, management and research

Premised on the recognition that psychological wellbeing is a vital component of optimal productivity, and the need for agricultural extension to enhance farmers' welfare, the study was motivated by a dearth of research on the construction and determinants of psychological wellbeing and gender roles in farm-families. The intention was to gain insight and understanding of the farmers' life experiences, peculiar needs, problems and aspirations, in their unique socio-historical and cultural contexts. The study explored the complexities of the socio-cultural construction of gender roles and psychological wellbeing in farm-families of Ogun state Nigeria. The study is interdisciplinary in nature, drawing from and contributing to the bodies of knowledge in gender-based research, social psychology, family studies, and agricultural extension. Findings reveal a need for the development of gender-sensitive and culture-specific strategies in the agricultural extension system, aimed at improving psychological wellbeing and livelihood security of farm-families and ultimately enhancing sustainable agricultural and national development. Keywords: gender, farm-families, implications for extension, Nigeria South African Journal of Agricultural Extension Vol. 34(1) 2005: 122-13

Biosorption of Fe (II) and Cd (II) ions from aqueous solution using a low cost adsorbent from orange peels

The peels from orange are less expensive biomaterials with excellent adsorption capacities. Orange peels were carbonized at 450 ºC, purified, activated with orthophosphoric acid and modified with citric acid to obtain Modified and Activated carbon which were used as low cost adsorbent to adsorb Cd(II) and Fe(II) metal ions. The effects of initial metal ions concentration; pH; temperature; contact time; and adsorbents dose on the removal of metal ions were investigated. The maximum adsorption occurs at 26 ºC and decreased with increase in temperature while optimum adsorption took place at pH of 6. Both the Fe-MOP and Fe-AOP system attained equilibrium in 60 minutes but Cd-MOP & Cd-AOP attained equilibrium at 45mins. The enthalpy 0f adsorption ranged from 2.48 KJ/mol to 14.418 KJ/mol and the entropy of adsorption ranged from -3.53 KJ/mol to 41.07 KJ/mol for both adsorbents (MOP and AOP). The kinetic studies showed that the adsorption process fitted well for pseudo-second order rate expression. Both MOP and AOP has much affinity for Fe(II) uptake than Cd(II) ion and the adsorption data fitted most into Freundlich but the highest adsorption capacity of 0.895 was obtained from Temkin. The presence of hydroxyl, alkyl, ether and aldehyde groups was confirmed by Infrared while the SEM shows porous surface characteristics suitable for adsorption.Keywords: Modified Orange peel, adsorbent dose, Isotherm, adsorption, Activated Orange pee

Adenosine and lidocaine (AL) combination dilates intimally damaged rat thoracic aortic rings and guinea pig mesenteric arteries: possible significance to cardiac surgery

New pharmacotherapies are required to improve vessel graft protection and prevent vasoconstriction and spasm in CABG surgery. Previously we have studied adenosine (A) and lidocaine (L) relaxation in rat aortic rings, and reported a possible crosstalk between L relaxation and adenosine A(2a) receptor inhibition. The aim of the present study was to examine the effect of AL combination compared to A and L alone on relaxation in intact and denuded rat aortic rings and in guinea-pig pressurized mesenteric arterial segments. Aortic rings were harvested from Sprague-Dawley rats and equilibrated in an organ bath containing modified Krebs-Henseleit (KH) solution, pH 7.4, 37 degrees C. Rings were pre-contracted sub-maximally with 0.3 mu M norepinephrine, and the effects of increasing AL, A or L (up to 1.0 mM) were examined in intact and denuded rings. Mesenteric artery segments were isolated from guinea-pigs and mounted in an arteriograph containing KH solution and pressurised to 60 mmHg. Arteries were preconstricted with 10(-8) M vasopressin and AL, A, or L was administered luminally or abluminally. Diameters were measured using video-microscopy. We report in intact rat aortic rings, AL increased relaxation from 21 to 100% (0.1-1.0 mM) and relaxation was endothelium-independent. Adenosine alone was also a potent relaxant of aortic rings but, unlike AL relaxation, it was partially endothelium-dependent. In intact mesenteric artery segments, increasing luminal AL produced a potent endothelium-independent dilation (up to 90%). Adenosine dilation was endothelium-independent but not lidocaine, which produced 33% dilation only after endothelial removal. Extra-luminal AL and A led to 76% and 80% dilationin intact segments respectively, whereas L resulted in constriction (10-17%). In conclusion, we show that AL can dilate aortic rings and mesenteric artery segments by up to 90% regardless of whether the endothelium is intact. We discuss the potential translational significance of AL to improve conduit protection in cardiac surgery, and other major surgeries

Performance of high rate space-time trellis coded modulation in fading channels.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.Future wireless communication systems promise to offer a variety of multimedia services which require reliable transmission at high data rates over wireless links. Multiple input multiple output (MIMO) systems have received a great deal of attention because they provide very high data rates for such links. Theoretical studies have shown that the quality provided by MIMO systems can be increased by using space-time codes. Space-time codes combine both space (antenna) and time diversity in the transmitter to increase the efficiency of MIMO system. The three primary approaches, layered spacetime architecture, space-time trellis coding (STTC) and space-time block coding (STBC) represent a way to investigate transmitter-based signal processing for diversity exploitation and interference suppression. The advantages of STBC (i.e. low decoding complexity) and STTC (i.e. TCM encoder structure) can be used to design a high rate space-time trellis coded modulation (HR-STTCM). Most space-time codes designs are based on the assumption of perfect channel state information at the receiver so as to make coherent decoding possible. However, accurate channel estimation requires a long training sequence that lowers spectral efficiency. Part of this dissertation focuses on the performance of HR-STTCM under non-coherent detection where there is imperfect channel state information and also in environment where the channel experiences rapid fading. Prior work on space-time codes with particular reference to STBC systems in multiuser environment has not adequately addressed the performance of the decoupled user signalto-noise ratio. Part of this thesis enumerates from a signal-to-noise ratio point of view the performance of the STBC systems in multiuser environment and also the performance of the HR-STTCM in such environment. The bit/frame error performance of space-time codes in fading channels can be evaluated using different approaches. The Chemoff upper-bound combined with the pair state generalized transfer function bound approach or the modified state transition diagram transfer function bound approach has been widely used in literature. However, although readily detennined, this bound can be too loose over nonnal signal-to-noise ranges of interest. Other approaches, based on the exact calculation of the pairwise error probabilities, are often too cumbersome. A simple exact numerical technique, for calculating, within any desired degree of accuracy, of the pairwise error probability of the HR-STTCM scheme over Rayleigh fading channel is proposed in this dissertation

Performance analysis of channel codes in multiple antenna OFDM systems

Multiple antenna techniques are used to increase the robustness and performance of wireless networks. Multiple antenna techniques can achieve diversity and increase bandwidth efficiency when specially designed channel codes are used at the scheme’s transmitter. These channel codes can be designed in the space, time and frequency domain. These specially designed channel codes in the space and time domain are actually designed for flat fading channels and in frequency selective fading channel, their performance may be degraded. To counteract this possible performance degradation in frequency selective fading channel, two main approaches can be applied to mitigate the effect of the symbol interference due to the frequency selective fading channel. These approaches are multichannel equalisation and orthogonal frequency division multiplexing (OFDM). In this thesis, a multichannel equalisation technique and OFDM were applied to channel codes specially designed for multiple antenna systems. An optimum receiver was proposed for super-orthogonal space-time trellis codes in a multichannel equalised frequency selective environment. Although the proposed receiver had increased complexity, the diversity order is still the same as compared to the code in a flat fading channel. To take advantage of the multipath diversity possible in a frequency selective fading channel, super-orthogonal block codes were employed in an OFDM environment. A new kind of super-orthogonal block code was proposed in this thesis. Super-orthogonal space-frequency trellis-coded OFDM was proposed to take advantage of not only the possible multipath diversity but also the spatial diversity for coded OFDM schemes. Based on simulation results in this thesis, the proposed coded OFDM scheme performs better than all other coded OFDM schemes (i.e. space time trellis-coded OFDM, space-time block coded OFDM, space-frequency block coded OFDM and super-orthogonal space-time trellis-coded OFDM). A simplified channel estimation algorithm was proposed for two of the coded OFDM schemes, which form a broad-based classification of coded OFDM schemes, i.e. trelliscoded schemes and block-coded schemes. Finally in this thesis performance analysis using the Gauss Chebychev quadrature technique as a way of validating simulation results was done for super-orthogonal block coded OFDM schemes when channel state information is known and when it is estimated. The results obtained show that results obtained via simulation and analysis are asymptotic and therefore the proposed analysis technique can be use to obtain error rate values for different SNR region instead of time consuming simulation.Thesis (PhD)--University of Pretoria, 2012.Electrical, Electronic and Computer Engineeringunrestricte

Polymyositis Initiation Involving Amlodipine Besylate

© 2006 R. M. Golding, L. G.F. Giles and E. M. Sokoya. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Based on extensive blood pressure data and results from a scientific model of the analysis of the rate processes involved in polymyositis the evidence suggests that the polymyositis in a particular patient was initiated by taking the drug amlodipine besylate (norvasc). The method of our analysis should serve as a foundation in handling other drug related interactions

Management of Enophthalmos from Silent Sinus Syndrome with a Customized Orbital Implant

Background We describe the surgical treatment of silent sinus syndrome, a disease characterized by progressive enophthalmos and hypoglobus due to orbital floor collapse with opacification of the maxillary sinus, in the presence of chronic maxillary sinusitis. Methods Case study of a 55-year-old male with persistent diplopia secondary to left-sided esotropia and enophthalmos from chronic maxillary sinusitis. Results Two stage procedure to treat the sinonasal and orbital symptoms, which include endoscopic sinus surgery to treat the underlying the ostial obstruction along with decompression of maxillary sinus. Then, reconstruction of the orbital floor with a customized implant. Conclusions Though the treatment of silent sinus syndrome can be challenging, we demonstrate the successful use of a customized orbital implant in the treatment of diplopia and enophthalmos from silent sinus syndrome using a two-stage approach

Orbital Skull Base Reconstruction with Temporalis Muscle: The Sphenoid Keyhole Technique

The temporalis flap is a common flap used in head and neck reconstruction. In this article, the authors present a new modification of the use of the temporalis muscle flap for orbital skull base reconstruction with the use of a sphenoid keyhole. This technique confers multiple advantages in reducing the arc of rotation and providing a tension-free reconstruction of the orbital skull base