Showing papers in "Journal of Biomedical Science and Engineering in 2011"

Implementation of an open-source customizable minimization program for allocation of patients to parallel groups in clinical trials

Abstract: Current minimization programs do not permit full control over different aspects of minimization algorithm such as distance or probability measures and may not allow for unequal allocation ratios. This article describes the implementation of “MinimPy” an open-source minimization program in Python programming language, which provides full customizetion of minimization features. MinimPy supports naive and biased coin minimization together with various new and classic distance measures. Data syncing is provided to facilitate minimization of multicenter trial over the network. MinimPy can easily be modified to fit special needs of clinical trials and in particular change it to a pure web application, though it currently supports network syncing of data in multi-center trials using network repositories.

Cardiac arrhythmias detection in an ECG beat signal using fast fourier transform and artificial neural network

Abstract: Cardiac Arrhythmias shows a condition of abnor-mal electrical activity in the heart which is a threat to humans. This paper presents a method to analyze electrocardiogram (ECG) signal, extract the fea-tures, for the classification of heart beats according to different arrhythmias. Data were obtained from 40 records of the MIT-BIH arrhythmia database (only one lead). Cardiac arrhythmias which are found are Tachycardia, Bradycardia, Supraventricular Tachycardia, Incomplete Bundle Branch Block, Bundle Branch Block, Ventricular Tachycardia. A learning dataset for the neural network was obtained from a twenty records set which were manually classified using MIT-BIH Arrhythmia Database Directory and docu- mentation, taking advantage of the professional experience of a cardiologist. Fast Fourier transforms are used to identify the peaks in the ECG signal and then Neural Networks are applied to identify the diseases. Levenberg Marquardt Back-Propagation algorithm is used to train the network. The results obtained have better efficiency then the previously proposed methods.

Thermal stability of proteins in the presence of aprotic ionic liquids

Abstract: Thermal stability of lysozyme dissolved in aqueous solutions was examined in the presence of water-miscible aprotic ionic liquids consisting of 1-ethyl-3-methylimidazolium cation and several kinds of anions. Addition of ionic liquids to an aqueous solution containing lysozyme prevented unfolded proteins from aggregating irreversibly at high temperatures. The thermal denaturation curve of lysozyme with ionic liquids was entirely shifted to higher temperature, compared with that without ionic liquids. The remaining activity of lysozyme after the heat treatment was markedly dependent upon the kind and concentration of ionic liquids. The remaining activi-ties of lysozyme with 1.5 M 1-ethyl-3-methylimida-zolium tetrafluoroborate ([emim][BF4]) and 0.1 M 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][Tf]) exhibited 88 and 68% after the heat treatment at 90oC for 30 min, respectively, although that without ionic liquids was perfectly lost.

Early detection of sudden cardiac death by using classical linear techniques and time-frequency methods on electrocardiogram signals

Abstract: Early detection of sudden cardiac death may be used for surviving the life of cardiac patients. In this paper we have investigated an algorithm to detect and predict sudden cardiac death, by processing of heart rate variability signal through the classical and time-frequency methods. At first, one minute of ECG signals, just before the cardiac death event are extracted and used to compute heart rate variability (HRV) signal. Five features in time domain and four features in frequency domain are extracted from the HRV signal and used as classical linear features. Then the Wigner Ville transform is applied to the HRV signal, and 11 extra features in the time-frequency (TF) domain are obtained. In order to improve the performance of classification, the principal component analysis (PCA) is applied to the obtained features vector. Finally a neural network classifier is applied to the reduced features. The obtained results show that the TF method can classify normal and SCD subjects, more efficiently than the classical methods. A MIT-BIH ECG database was used to evaluate the proposed method. The proposed method was implemented using MLP classifier and had 74.36% and 99.16% correct detection rate (accuracy) for classical features and TF method, respectively. Also, the accuracy of the KNN classifier were 73.87% and 96.04%.

Comparison of SVM and ANN for classification of eye events in EEG

Abstract: The eye events (eye blink, eyes close and eyes open) are usually considered as biological artifacts in the electroencephalographic (EEG) signal. One can con-trol his or her eye blink by proper training and hence can be used as a control signal in Brain Computer Interface (BCI) applications. Support vector ma-chines (SVM) in recent years proved to be the best classification tool. A comparison of SVM with the Artificial Neural Network (ANN) always provides fruitful results. A one-against-all SVM and a multi-layer ANN is trained to detect the eye events. A com-parison of both is made in this paper.

Next generation sequencing for profiling expression of miRNAs: technical progress and applications in drug development.

Abstract: miRNAs are non-coding RNAs that play a regulatory role in expression of genes and are associated with diseases. Quantitatively measuring expression levels of miRNAs can help understanding the mechanisms of human diseases and discovering new drug targets. There are three major methods that have been used to measure the expression levels of miRNAs: real-time reverse transcription PCR (qRT-PCR), microarray, and the newly introduced next-generation sequencing (NGS). NGS is not only suitable for profiling of known miRNAs that qRT-PCR and microarray can do too but also able to detect unknown miRNAs that the other two methods are incapable. Profiling of miRNAs by NGS has been progressed rapidly and is a promising field for applications in drug development. This paper will review the technical advancement of NGS for profiling miRNAs, including comparative analyses between different platforms and software packages for analyzing NGS data. Examples and future perspectives of applications of NGS profiling miRNAs in drug development will be discussed.

Medical ultrasound image segmentation using genetic active contour

Abstract: Image segmentation is one of the earliest and most important stages of image processing and plays an important role in both qualitative and quantitative analysis of medical ultrasound images but ultrasound images have low level of contrast and are corrupted with strong speckle noise. Due to these effects, segmentation of ultrasound images is very challenging and traditional image segmentation methods may not be leads to satisfactory results. The active contour method has been one of the widely used techniques for image segmentation; however, due to low quality of ultrasound images, it has encountered difficulties. In this paper, we presented a segmental method combined genetic algorithm and active contour with an energy minimization procedure based on genetic algorithms. This method have been proposed to overcome some limits of classical active contours, as con-tour initialization and local minima (speckle noise), and have been successfully applied on medical ultrasound images. Experimental result on medical ultrasound image show that our presented method only can correctly segment the circular tissue’s on ultra-sound images.

Synthesis and evaluation of a novel antibacterial dental resin composite with quaternary ammonium salts

Abstract: The novel quaternary ammonium bromide (QAB)-containing oligomers were synthesized and applied for developing an antibacterial resin composite. Compressive strength (CS) and S. mutans (an oral bacteria strain) viability were used to evaluate the mechanical strength and antibacterial activity of the formed composites. All the QAB-modified resin composites showed significant antibacterial activity and mechanical strength reduction. Increasing chain length and loading significantly enhanced the antibacterial activity but dramatically reduced the CS as well. The 30-day aging study showed that the incorporation of the QAB accelerated the degradation of the composite, suggesting that the QAB may not be well suitable for development of antibacterial dental resin composites or at least the QAB loading should be well controlled, unlike its use in dental glass-ionomer cements. The work in this study is beneficial and valuable to those who are interested in studying antibacterial dental resin composites.

Antimicrobial silver nanoparticle induces organ deformities in the developing Zebrafish (Danio rerio) embryos

Abstract: Silver Nanoparticles were synthesized by Esche- richia coli using Silver nitrate in the growth me-dium and characterized in X-Ray Diffraction, UV-Vis Spectrophotometer and Scanning Electron Microscope. They exhibited antimicrobial activity against human pathogens except Escherichia Coli. Nanoparticles were impregnated in yarn and ana-lyzed for their inhibition in the broth culture. The Minimal Inhibitory Concentratio was calculated for the human pathogens in Microtitre plate. The toxicity assessment of the nanoparticles in the embry-onic Zebrafish showed many organogensis deformi-ties like cardiac malformations, eye and head edema, tail and trunk flexure were observed in the organ system of the developing embryos for 1 to 5 day post fertilization in different concentrations of Ag Nanoparticles. The Organogenesis disruptive effects were found in 14 - 20 ng/ml of silver nanoparticles but the inhibition was found in 4-10ng/ml for the pathogens in vitro and 10ng/ml in embryos. Nevertheless, in Cardiac assay, the Heart Beat rates were calculated as 42 - 45 for 15 Sec in the concentrations ranging from 10 - 20 ng/ml of Silver nanoparticles. The blood flows, rhythmicity, contractility of heart beat rates were observed normal. The Mean value of blood Cell counting did not showed any notable effects in the Nanoparticle treated Zebrafish embryos and control. The LC50 value for the Biosynthesized nanoparticle was at 22 ng/ml in all the developmental stages of the em-bryos. Our results shows silver nanoparticles dis-rupts the normal organogenesis during development and further detailed studies are needed to prove silver nanopartcles are an antimicrobial agent for use in humans.

Twenty years study of solar, geomagnetic, cosmic ray activity links with monthly deaths number (n-850304)

Abstract: The interrelationship between human life and death at the end of the XX and beginning of the XXI centuries is the topic of this study. The aim of the study is to study links between time, Solar (SA), Geomagnetic (GMA) and Cosmic Ray (CRA) (Neutron) activity and monthly deaths distribution from all and six subgroups of death causes in years 1990-2009 for additional clarification of the role of exogenic factors in human homeostasis. Methods and patients: 850304 deaths (44657 men, 400647 woman) and 6 subgroups were studied in 240 consecutive months in the Republic of Lithuania in relation to the months of year (1 - 12), 4 indices of SA (Sunspot number and Solar Flux), 3 indices of GMA (planetary and regional for the Middle Latitudes), and CRA described by Neutron activity on the Earth's surface-remains of crushed atoms in the high space levels and measured by Imp/min. The cosmophysical data came from Space Science Institutions in the USA, Russia and Finland. Statistical analysis of the results for monthly comparison are presented. Results: It was a significant and inverse relationship of monthly deaths number for both gender with CRA and SA, less with GMA. It was a significant drop of deaths from IHD and suicides. Oncology deaths also show similarity in their timing with other groups. A strong inverse relationship was seen in monthly death number from IHD and Stroke. (r = -0.76, p < 0.0001), woman show more seasonality in death's distribution. Most deaths show annual rhythm with acrophase in February. Only Suicide pick appears in the summer months. Conclusion: at the beginning of the XXI century, in addition to accepted risk factors, environmental physical activity is linked to timing of death. Cosmic Ray (Neutron) activity is one of the main regulators of this relationship. Stroke related deaths are becoming a more prominent cause in the collection of cardiovascular deaths. Suicide related deaths show a drop, possibly related to a massive trend for immigration in the high risk group of the population. The precise mechanism of action of the studied physical factors needs additional studies.

Polymer-based nanoparticulate solid dispersions prepared by a modified electrospraying process

Abstract: A modified electrospraying process is exploited to enhance the dissolution profiles of a poorly water-soluble drug. With polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix and ketoprofen (KET) as a model drug, polymer-drug composites in the form of nanoparticles were prepared and characterized. The surface morphologies, the physical status of the drug, and the drug-polymer interactions were studied using FESEM, DSC, XRD, and ATR-FTIR. FESEM observations demonstrated that the nanoparticles gradually decreased in size from 640 ± 350, to 530 ± 320, 460 ± 200 and 320 ± 160 nm as the KET content increased from 0, to 9.1%, 16.7% and 33.3% w/w, respectively. Results from DSC and XRD suggested that KET was distributed in the PVP matrix in an amorphous manner at the molecular level. This is thought to be due to their compatibility, arising through hydrogen bonding as demonstrated by ATR- FTIR spectra. In vitro dissolution tests showed that the nanoparticles released the incorporated KET within 1 min, evidencing markedly improved dissolution over pure KET and a KET-PVP physical mixture. Electrospraying can hence offer a facile route to develop new polymer composites for biomedical applications, in particular for improving dissolution rate of poorly water-soluble drugs.

A review of developments of EEG-based automatic medical support systems for epilepsy diagnosis and seizure detection

Abstract: Epilepsy is one of the most common neurological disorders-approximately one in every 100 people worldwide are suffering from it. The electroencephalogram (EEG) is the most common source of information used to monitor, diagnose and manage neurological disorders related to epilepsy. Large amounts of data are produced by EEG monitoring devices, and analysis by visual inspection of long recordings of EEG in order to find traces of epilepsy is not routinely possible. Therefore, automated detection of epilepsy has been a goal of many researchers for a long time. Until now, reviews of epileptic seizure detection have been published but none of them has specifically reviewed developments of automatic medical support systems utilized for EEG-based epileptic seizure detection. This review aims at filling this lack. The main objective of this review will be to briefly discuss different methods used in this research field and describe their critical properties.

Investigation of changes in thickness and reflectivity from layered retinal structures of healthy and diabetic eyes with optical coherence tomography

Abstract: OCT is usually employed for the measurement of retinal thickness. However, coherent reflected light carries more information characterizing the optical properties of tissue. Therefore, optical property changes may provide further information regarding cellular layers and early damage in ocular diseases. We investigated the possibility of OCT in detecting changes in the optical backscattered signal from layered retinal structures. OCT images were obtained from diabetic patients without retinopathy (DM, n = 38 eyes) or mild diabetic retinopathy (MDR, n = 43 eyes) and normal healthy subjects (n = 74 eyes). The thickness and reflectivity of various layered structures were assessed using a custom-built algorithm. In addition, we evaluated the usefulness of quantifying the reflectivity of layered structures in the detection of retinal damage. Generalized estimating equations considering within-subject inter-eye relations were used to test for differences between the groups. A modified p value of <0.001 was considered statistically significant. Receiver operating characteristic (ROC) curves were constructed to describe the ability of each parameter to discriminate between the eyes of DM, MDR and healthy eyes. Thickness values of the GCL + IPL and OPL showed a significant decrease in the MDR eyes compared to controls. Significant decreases of total reflectance average values were observed in all layers in the MDR eyes compared with controls. The highest AUROC values estimated for the total reflectance were observed for the GCL+IPL, OPL and OS when comparing MDR eyes with controls. Total reflectance showed a better discriminating power between the MDR eyes and healthy eyes compared to thickness values. Our results suggest that the optical properties of the intraretinal layers may provide useful information to differentiate pathological from healthy eyes. Further research is warranted to determine how this approach may be used to improve diagnosis of early retinal neurodegeneration.

Immobilization of antibodies on the self-assembled monolayer by antigen-binding site protection and immobilization kinetic control

Abstract: The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-binding site of the antibody prior to immo-bilization to -functionalized mixed self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 1-heptanethiol. More importantly, the number of immobilization bonds formed between each an-tigen-binding site protected antibody molecule and the solid surface was controlled by optimizing the mole fraction of the activated carboxyl group of the linker molecules in the mixed SAM. The amount of antibody used in this study was approximately equivalent to the amount for one monolayer surface coverage. The resulting activity of protected immo-bilized antibody was about 10 fold higher than that of random immobilized antibody

The effects of different sterilization methods on silk fibroin

Abstract: The aim of this study was to investigate the changes in the molecular structure and physiological activities of silk fibroin induced by three different sterilization methods (steam, gamma radiation and ethylene oxide) with different dose or time period of sterilization by means of Fourier transform infrared (FT-IR) spec-troscopy, X-ray diffraction, mechanical properties and assessment of molecular weight. The results showed that the steam sterilization darkened the color of silk fibroin and obviously affected the mechanical property; gamma irradiation slightly degraded the molecular weight of silk fibroin and the speed of degradation increased with increasing irradiation dose; and ethylene oxide almost had no influence on silk fibroin expect for some slight hydrolysis on mo-lecular weight. Because ethylene oxide sterilization had the smallest influence on the quality of silk fi-broin with compared to other sterilization methods, it could be used as an efficient method to make fibroin more suitable for the development of functional foods and cosmetics.

Identification and low-complexity regime-switching insulin control of type I diabetic patients

Abstract: This paper studies benefits of using simplified re-gime-switching adaptive control strategies in improving performance of insulin control for Type I diabetic patients. Typical dynamic models of glucose levels in diabetic patients are nonlinear. Using a linear time invariant controller based on an operating condition is a common method to simplify control design. On the other hand, adaptive control can potentially improve system performance, but it increases control complexity and may create further stability issues. This paper investigates patient models and presents a simplified switching control scheme using PID controllers. By comparing different switching schemes, it shows that switched PID controllers can improve performance, but frequent switching of controllers is unnecessary. These findings lead to a control strategy that utilizes only a small number of PID controllers in this scheduled adaptation strategy.

Patients' specific simulations of coronary fluxes in case of three-vessel disease

Abstract: In this work, we propose a model of the coronary circulation based on hydraulic/electric analogy. This model aims to provide quantitative estimations of the distribution of flows and pressures across the coro-nary network for patients with stenoses of the left main coronary artery (LMCA), left anterior de-scending artery (LAD) and left circumflex branch (LCx), and chronic occlusion of the right coronary artery (RCA), undergoing off-pump coronary sur-gery. The results of the simulations are presented for 10 patients with various stenoses grades and collat-eral supply. For each patient, the four revasculariza-tion situations (no graft operating, pathological situa-tion (0G); right graft only (1G), left grafts only (2G), complete revascularization (3G)) are considered. It is shown that: 1) the complete revascularization is fully justified for these patients because neither the right graft alone, nor the left grafts alone can ensure a suf-ficient perfusion improvement for the heart; 2) the capillary and collateral resistances (and the propor-tion between them) have a major impact on the flows and pressures everywhere in the network; 3) in the presence of the left grafts, the flows in the native stenosed arteries become low and this could promote the development of the native disease in these branches.

A doublet mechanics model for the ultrasound characterization of malignant tissues

Abstract: Non invasive ultrasound-based imaging systems are being more commonly used in clinical bio-microscopy applications for both ex vivo and in vivo analysis of tissue pathological and physiological states. These modalities usually employ high-frequency ultrasound systems to overcome spatial resolution limits of conventional clinical diagnostic approaches. Biological tissues are non continuous, non homogeneous and exhibit a multiscale organization from the sub-cellular level (£1 mm) to the organ level (³1 cm). When the ultrasonic wavelength used to probe the tissues becomes comparable with the tissue's microstructure scale, the propagation and reflection of ultrasound waves cannot be fully interpreted employing classical models developed within the continuum assumption. In this study, we present a multiscale model for analyzing the mechanical response of a non-continuum double-layer system exposed to an ultrasound source. The model is developed within the framework of the Doublet Mechanics theory and can be applied to the non-invasive analysis of complex biological tissues.

Development of forearm impedance plethysmography for the minimally invasive monitoring of cardiac pumping function

Abstract: It is essential to continuously and non-invasively monitor the cardiac pumping function in clinical setting. Thus, the study aimed to explore a regional impedance phethysmographic method to assess the changes in stroke volume. To do this, we developed a plethysmographic device that was capable of delivering a single-frequency current with constant amplitude and of recording electrical impedance signals of biological tissue. The electrical impedance plethy- smographic waveform form the lower arm was measured with the impedance plethysmographic device, and simultaneously the end-systolic and end- diastolic volumes of the left ventricle were obtained with a two-dimension echocardiographic system in fourteen healthy subjects before and immediately after a thirty-second breath-hold maneuver. For the 14 subjects, a linear correlation coefficient of 0.79 (p < 0.001) was obtained between the changes in peak amplitude of the forearm impedance waveform and the changes in stroke volume before and just after the breath-hold test. In addition, the changes in the mean area under the impedance curve and the change in stroke volume were also correlated linearly (r = 0.71, p < 0.005). In summary, the forearm impedance plethysmography may be employed to evaluate the beat-to-beat alteration in cardiac stroke volume, suggesting its potential for long-term monitoring cardiac pumping performance.

Analysis of trans tibial prosthetic socket materials using finite element method

Abstract: The objective of this work was to analyze in a parametric study for optimum design solution of prosthetic socket material by finite element method. A realistic three-dimensional finite element model of the PTB socket was developed to find out the stress distribution pattern under physiologically relevant loading condition during normal walking. The CAD model of the rectified socket was collected from a CMET 250 non-tactile high accuracy (0.06 mm) white light scanner and analyses were carried out using finite element Method in ANSYS®. All structural materials used in the analysis were assumed to be linearly elastic, homogeneous and isotropic. Different materials were used for socket and only polypropylene was used for socket adopter. Analysis was prepared at 2 mm, 3 mm, 4 mm, 5 mm & 6 mm thickness of socket in different materials commonly used in developing countries. The bottom line of socket was made to zero displacement constraints and vertical loads in relation to stance phase of gait cycle were applied under static condition at the patella tendon brim. The 3 mm laminated composite sockets was found to be optimum in terms of strength, weight and factor of safety.

Increase in thermal stability of proteins adsorbed on biomass charcoal powder prepared from plant biomass wastes

Abstract: Thermal stability of lysozyme adsorbed on biomass charcoal powder (BCP), which was prepared from plant biomass wastes such as dumped adzuki bean, bamboo, and wood by pyrolysis without combustion under nitrogen atmosphere and comminution with a jet mill, was examined. Adsorbing lysozyme on BCP could sufficiently prevent proteins from denaturing and aggregating in an aqueous solution at high temperatures, and enhanced the refolding of thermally denatured proteins by cooling treatment. The remaining activities of lysozyme adsorbed on BCP of adzuki bean exhibited 51% by cooling treatment after the heat treatment at 90?C for 30 min, although that of native lysozyme was almost lost under the same experimental conditions. The thermostabilization effect of BCP on the remaining activity of adsorbed lysozyme was markedly dependent upon the kind of plant biomass wastes.

In vitro degradation behavior of chitosan based hybrid microparticles

Abstract: The degradation properties of the MPs is important to the long-term benefits of the use of the chitosan (CS) based hybrid MPs in bone tissue-engineering, because the degradation kinetics could affect a multitude of processes within the cell, such as cell growth, tissue regeneration, and host response. The aim of this study was to investigate the degradation of solid, hybrid CS microparticles (MPs), CS-10% calcium phosphate (CaHPO4, w/w), and CS-10% calcium carbonate (CaCO3, w/w) MPs in phosphate buffered solution (PBS) over a 30-week period. The hybrid MPs were synthesized by emulsification technique, cross-linked with 64% sodium tripolyphosphate (TPP), purified and air dried overnight. Each sample had 30 mg of MPs was placed in a glass vial with 9 ml of PBS added and then the vial was closed to prevent evaporation. Every week 4 ml of the incubated solution was removed for sample measurement and all samples were replaced with an equivalent amount of fresh medium. The samples were maintained at 37oC under continuous shaking. The hybrid MPs were measured for pH and calcium release, every week in triplicate. At 0, 5, 10, 15, 20, 25, and 30 weeks, surface and bulk morphology were analyzed with a scanning electron microscope (SEM). The degradation data suggested that the hybrid MPs were stable at least up to 25 week and maintain the physiologically relevant pH. Therefore, we can use these hybrid MPs to apply in the bone tissue engineering applications since they do not degrade within a short period.

X-ray digital linear tomosynthesis imaging

Abstract: Aims: The purpose of this review includes the fol-lowing: 1) to identify indications for volumetric X-ray digital linear tomosynthesis by using a filtered back projection (FBP) algorithm and 2) to compare X-ray digital linear tomosynthesis, X-ray digital ra-diography, conventional tomography, and computed tomography. Review: The methods include the fol-lowing: 1) an overview of the tomosynthesis system in comparison with conventional X-ray imaging tech-nology; 2) an overview of the properties of diagnostic imaging for the chest, hip joint, and temporomandibular joint when imaging overlying structures and their effect of various artificial images; and 3) a review of each system. Summary: Tomosynthesis is worthy of further evaluation because of its flexibility and ability to suppress streak artifacts through an appropriate choice of an FBP algorithm. Tomosynthesis may be considered the imaging technique of choice for investigation of bone changes and detection of pulmonary nodules. Understanding the potential of tomosynthesis imaging will improve diagnostic accuracy in clinical applications.

The effect of amblyopia on educational activities of students aged 9 - 15

Abstract: Amblyopia is an illness with reduced vision and a number of students are affected with this disease To determine any association of amblyopia with educational activities, sport and social activities of students involved by amblyopia, this study was carried on This study was conducted at Boali Hospital in Gazvin, Iran: A total of 110 patients 9 to 15 years (545% female and 455% male; mean age: 137 ± 32) with amblyopia (20/25 - 20/400) due to strabismus and/or refractive errors, and that persisted after treatment with spectacles All children wore eyeglasses containing their refractive correction (based on cycloplegic autorefractor measurements, refined or confirmed by cycloplegic retinoscopy or subjective refinement) for acuity testing The results indicated that, 25 (2273%) patients with strabismus amblyopia, 40 (3636%) patients anisometropic amblyopia, 22 (20%) patients ametropic amblyopia, 18 (1636%) patients with strabismic mixed with anisometropia and 5 (455) with deprived amblyopia Parent’s knowledge about meaning of amblyopia and amblyopia-related phenomena in 50 (455%) of patiens was very low The educational level in 45 (41%) of parents were reported to be primary school, 40 (363%) higher school and university degrees 25 (227%) The sport activity in 35 (318%) of patients with amblyopia was very low and in 14 (127%) higher than others In a comparison with other students, the educational qualification in 18 (164%) was very low, 35 (32%) the as equal as others and 27 (245%) higher than their classmate Visual acuity with the best correction, in 75 (67%) of patients was 20/25, in 30 (2727%) patients 20/40 or worse and in 5 (45%) of them 20/200 or worse Poor eyesight and amblyopia can influence on learning, sport and social activity, and performance in school, as well as restrict choice in profession and hobbies The parent’s knowledge of amblyopia is high efficiency of treatment of the amblyopia patient’s morale

Prevention of Staphylococcus aureus biofilm formation on metallic surgical implants via controlled release of gentamicin

Abstract: Implant associated infections are a critical health concern following orthopaedic surgery. Sustained local delivery of antibiotics has been suggested as a means of preventing these infections. Poly(D,L-lactide) (PDLLA) is a biodegradable polymer that has been used to coat implants for the delivery of antibiotics and other bioactive molecules. While effective, these studies show that antibiotics are released in a burst profile. Here we evaluated a method for controlled release of gentamicin from implant surfaces using the palmitate alkyl salt to decrease its solubility in aqueous solution. Steel Kirschner wires (K-wires) were coated with Gentamicin-palmitate (GP)-PDLLA, gentamicin sulphate (GS)-PDLLA or vancomycin sulphate (VS)-PDLLA, and elution of antibiotics from coated K-wires investigated using HPLC/MS/ MS. In contrast to burst antibiotic release from the GS-PDLLA and VS-PDLLA groups, GP was released in a slower sustained manner. Colonisation and initial attachment of Staphylococcus aureus Xen29 to gentamicin-coated K-wires was reduced by 90% when compared to the non-coated control group. However there was no statistical difference in recovery of bacteria from GS or GP groups. Bacteria recovered from VS-PDLLA coated K-wires decreased by 36%. Bioluminescence emitted by S. aureus Xen29 was also reduced over seven days in the antibiotic control groups, demonstrating that growth and biofilm development over the longer term was impaired by antibiotic-PDLLA coating. These results indicate that using alkyl salts of antibiotics may be an effective strategy for controlling the release of antibiotics from implants.

Biomechanical comparison of distal locking screws for distal tibia fracture intramedullary nailing

Abstract: Background: Newer generation intramedullary (IM) tibial nails provide several distal interlocking screw options. The objectives were to determine: 1) if the new oblique interlocking option provides superior stability, 2) which screw orientation/ configuration is the most biomechanically stable, and 3) if three distal interlocking screws provide better stability. Methods: A preliminary experiment was performed in torsion, compression, and bending tests with four different screw configurations: (I) one medial-to-lateral and one oblique, (II) two me-dial-to-lateral, (III) one medial-to-lateral and one anterior-to-posterior, and (IV) one medial-to-lateral, one anterior-to-posterior and one oblique in simu-lated distal metaphyseal fracture tibiae. Twenty- four Synthes EXPERT tibial IM nails were used for six specimens of each screw configuration. Parts I and II, tibial IM nails were locked with 5.0 mm in-terlocking screws into simulated distal tibiae (PVC and composite analogue tibia). Part III, the two most stable configurations were tested using five pairs of simulated cadaveric distal tibiae metaphy-seal fractures. Results: Significant differences were attributable to distal screw orientation for intrame- dullary nailing of distal tibia fractures. Configura-tions II and IV were found to be more stable than the other two configurations. No significant differ-ence was detected in construct stability in all modes of testing between Configurations II and IV. Dis-cussion: Configuration I did not provide superior stability for the distal tibia fracture fixation. Con-figurations II and IV provided equivalent stability. When choosing IM fixation for treatment of distal tibia metaphyseal fractures two medial-to-lateral screws provide the necessary stability for satisfac-tory fixation. Clinical Relevance: This study indi-cated an option for operative treatment of distal metaphyseal tibia fracture fixation where preserva-tion of soft tissue and rigid stabilization are needed.

Comparison of fatigue behaviour of eight different hip stems: a numerical and experimental study

Abstract: In this study, finite element analysis was used to investigate the fatigue behavior of eight different hip stems. All of the prostheses investigated in the analysis are already being used in Turkish orthopaedic surgery. All stems were compared with each other in terms of fatigue, deformation and safety factors. Primary analysis was applied on three of the stems, which were tested experimentally. It was observed that the simulation and the experimental results are in good agreement with each other. After determining the reliability of the numerical method, the analysis was applied on all other stems. To obtain a more realistic simulation, boundary conditions were applied according to standards specified in the ISO 7206-4 standard. Three different types of materials were selected during analysis. These materials were Ti-6Al-4V, cobalt chrome alloy and 316L. Minimum fatigue cycles, critical fatigue areas, stresses and safety factor values have been identified. The results obtained from the finite element analysis showed that all stems were safe enough in terms of fatigue life. As a result of fatigue analysis, all stems have been found to be successful, but some of them were found to be better than the others in terms of safety factor. The current study has also demonstrated that analysing hip stems with the finite element method (FEM) can be applied with confidence to support standard fatigue testing and used as an alternative. Further studies can expand the simulations to the clinical relevance due to complex physical relevance.

Automatic DNA sequencing for electrophoresis gels using image processing algorithms

Abstract: DNA electrophoresis gel is an important biologically experimental technique and DNA sequencing can be defined by it. Traditionally, it is time consuming for biologists to exam the gel images by their eyes and often has human errors during the process. Therefore, automatic analysis of the gel image could provide more information that is usually ignored by human expert. However, basic tasks such as the identification of lanes in a gel image, easily done by human experts, emerge as problems that may be difficult to be executed automatically. In this paper, we design an automatic procedure to analyze DNA gel images using various image processing algorithms. Firstly, we employ an enhanced fuzzy c-means algorithm to extract the useful information from DNA gel images and exclude the undesired background. Then, Gaussian function is utilized to estimate the location of each lane of A, T, C, and G on the gels images automatically. Finally, the location of each band on the gel image can be detected accurately by tracing lanes, renewing lost bands, and eliminating repetitive bands.

Discrete wavelet and modified PCA decompositions for postural stability analysis in biometric applications

Abstract: The aim of this study is to compare the Discrete wavelet decomposition and the modified Principal Analysis Component (PCA) decomposition to analyze the stabilogram for the purpose to provide a new insight about human postural stability. Discrete wavelet analysis is used to decompose the stabilogram into several timescale components (i.e. detail wavelet coefficients and approximation wavelet coefficients). Whereas, the modified PCA decomposition is applied to decompose the stabilogram into three components, namely: trend, rambling and trembling. Based on the modified PCA analysis, the trace of analytic trembling and rambling in the complex plan highlights a unique rotation center. The same property is found when considering the detail wavelet coefficients. Based on this property, the area of the circle in which 95% of the trace’s data points are located, is extracted to provide important information about the postural equilibrium status of healthy subjects (average age 31 ± 11 years). Based on experimental results, this parameter seems to be a valuable parameter in order to highlight the effect of visual entries, stabilogram direction, gender and age on the postural stability. Obtained results show also that wavelets and the modified PCA decomposition can discriminate the subjects by gender which is particularly interesting in biometric applications and human stability simulation. Moreover, both techniques highlight the fact that male are less stable than female and the fact that there is no correlation between human stability and his age (under 60).

Bone blood flow is influenced by muscle contractions

Abstract: Forces acting on the skeleton could be divided into those originating from gravitational loading and those originating from muscle loading. Flat bones in a non-weight-baring segment of the skeleton probably experience forces mostly generated by muscle contractions. One purpose of muscle contractions is to generate blood flow within skeletal tissues. The present study aimed to investigate the pulsatile patellar bone blood flow after low and high intensity leg extension exercises. Forty-two healthy individuals volunteered for the study. Dynamic isotonic one leg extension/flexion exercises were performed in a leg extension machine. Randomly, the exercises were performed with the left or right leg with either 10 repetition maximum (10 RM) continuously without any resting periods (high intensity muscle work), or 20 RM with a 2 second rest between contractions (low intensity muscle work). The work load, expressed in kilograms totally lifted, was identical in both legs. The pulsatile patellar blood flow was recorded continuously using a photoplethysmographic technique. Blood pressure was measured continuously during muscle work by a non-invasive method (Finapress). The patellar pulsatile bone blood flow increased significantly more after high intensity muscle work (61%) compared to the same work load performed using a lower intensity (22%), p = 0.000073. Systolic blood pressure changed equally during and after both interventions. Post-exercise bone hyperaemia appears to be correlated to the intensity of muscle contractions in the muscle compartment attached to the bone.