To assess the outcome of cigarette smoking and non-smoking on the healing of bone around dental implants.
A retrospective analysis was made over 6 years of the clinical and radiographic findings ...corresponding to 60 consecutive patients (25 women and 35 men) who had received a total of 100 implants. Patients were divided into two groups: smokers, 32 patients (received 50 implants); and non-smokers (NSs), 28 patients (received 50 implants). Smokers were identified as people smoking >15 cigarettes per day. The success and failure cases were evaluated and studied. The data were analyzed using descriptive statistics.
Smokers and NSs received 50 implants in each group with 5 (10%) and 2 (4%) failures and 90% and 96% of success in smokers and NSs, respectively. Smokers had a higher failure rate than NSs. The difference was statistically significant.
The results indicated a higher success of implants in NSs compared to smokers.
A hybrid neuroprosthesis that combines human muscle power, elicited through functional electrical stimulation (FES), with a powered orthosis may be advantageous over a sole FES or a powered ...exoskeleton-based rehabilitation system. The hybrid system can conceivably overcome torque reduction due to FES-induced muscle fatigue by complementarily using torque from the powered exoskeleton. The second advantage of the hybrid system is that the use of human muscle power can supplement the powered exoskeleton's power (motor torque) requirements; thus, potentially reducing the size and weight of a walking restoration system. To realize these advantages, however, it is unknown how to concurrently optimize desired control performance and allocation of control inputs between FES and electric motor. In this paper, a model predictive control-based dynamic control allocation (DCA) is used to allocate control between FES and the electric motor that simultaneously maintain a desired knee angle. The experimental results, depicting the performance of the DCA method while the muscle fatigues, are presented for an able-bodied participant and a participant with spinal cord injury. The experimental results showed that the motor torque recruited by the hybrid system was less than that recruited by the motor-only system, the algorithm can be easily used to allocate more control input to the electric motor as the muscle fatigues, and the muscle fatigue induced by the hybrid system was found to be less than the fatigue induced by sole FES. These results validate the aforementioned advantages of the hybrid system; thus implying the hybrid technology's potential use in walking rehabilitation.
A hybrid walking neuroprosthesis that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton can be used to restore walking in persons with paraplegia. It provides ...therapeutic benefits of FES and torque reliability of the powered exoskeleton. Moreover, by harnessing metabolic power of muscles via FES, the hybrid combination has a potential to lower power consumption and reduce actuator size in the powered exoskeleton. Its control design, however, must overcome the challenges of actuator redundancy due to the combined use of FES and electric motor. Further, dynamic disturbances such as electromechanical delay (EMD) and muscle fatigue must be considered during the control design process. This ensures stability and control performance despite disparate dynamics of FES and electric motor. In this paper, a general framework to coordinate FES of multiple gait-governing muscles with electric motors is presented. A muscle synergy-inspired control framework is used to derive the controller and is motivated mainly to address the actuator redundancy issue. Dynamic postural synergies between FES of the muscles and the electric motors were artificially generated through optimizations and result in key dynamic postures when activated. These synergies were used in the feedforward path of the control system. A dynamic surface control technique, modified with a delay compensation term, is used as the feedback controller to address model uncertainty, the cascaded muscle activation dynamics, and EMD. To address muscle fatigue, the stimulation levels in the feedforward path were gradually increased based on a model-based fatigue estimate. A Lyapunov-based stability approach was used to derive the controller and guarantee its stability. The synergy-based controller was demonstrated experimentally on an able-bodied subject and person with an incomplete spinal cord injury.
Pectin and chitosan are natural polysaccharides obtained from fruit peels and exoskeletons of crustaceans and insects. They are safe for usage in food products and are renewable and biocompatible. ...They have further applications as wound dressings, body fat reduction, tissue engineering, and auxiliary agents in drug delivery systems. The healing process is usually long and painful. Adding a new material such as a pectin-chitosan composite to the implant surface or body would create unique biological responses to accelerate healing and delivery of target-specific medication at the implant site. The present study utilized the electrospraying process to create pectin-chitosan polyelectrolyte composite (PCPC) coatings with various ratios of 1:1, 2:1, 1:2, 1:3, and 3:1 on commercially pure titanium substrates. By means of FESEM, AFM, wettability, cross-cut adhesion, and microhardness were assessed the PCPC coatings' physical and mechanical properties. Subsequently, the antibacterial properties of the coating composite were assessed. AFM analysis revealed higher surface roughness for group 5 and homogenous coating for group 1. Group 3 showed the lowest water contact angle of 66.7° and all PCPC coatings had significantly higher Vickers hardness values compared to the control uncoated CpTi samples. Groups 3 and 4 showed the best adhesion of the PCPC to the titanium substrates. Groups 3, 4, and 5 showed antibacterial properties with a high zone of inhibitions compared to the control. The PCPC coating's characteristics can be significantly impacted by using certain pectin-chitosan ratios. Groups 3 (1:2) and 4 (1:3) showed remarkable morphological and mechanical properties with better surface roughness, greater surface strength, improved hydrophilicity, improved adhesion to the substrate surface, and additionally demonstrated significant antibacterial properties. According to the accomplished in vitro study outcomes, these particular PCPC ratios can be considered as an efficient coating for titanium dental implants.
A comparison of linear and non-linear regression method for predicting the optimum isotherm was made using the experimental adsorption equilibrium data of Cu(II) onto treated Martil sand (TMS). For ...this, six error analysis methods were used: the coefficient of determination r2, the sum of the squares of the errors, the sum of the absolute errors, the average relative error, the hybrid fractional error function and the Marquardt's percent standard deviation. The error values indicated that non-linear method is a better way to obtain the isotherm parameters describing the Cu(II) adsorption onto TMS. The comparison between different models such as Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Koble-Corrigan and Fritz-Schlünder showed that Fritz-Schlünder model was more suitable to describe the equilibrium data. Based on this result and in order to optimize the equilibrium model results for more accurate parameters values, the Fritz-Schlünder equation was modified and called modified Fritz-Schlünder model. As a comparison of such developed modified model to existing mentioned ones, the results showed that the adsorption equilibrium of Cu(II) onto TMS was better described by the modified Fritz-Schlünder model than by others.
Display omitted
•The determination of optimum equilibrium isotherm is investigated.•Non-linear regression is the best method to obtain the isotherm parameters.•Modified Fritz-Schlünder model is the best-fit isotherm among seven adsorption models.
Several hundred plant and herb species that have potential as novel antiviral agents have been studied, with surprisingly little overlap. A wide variety of active phytochemicals, including the ...flavonoids, terpenoids, lignans, sulphides, polyphenolics, coumarins, saponins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been identified. Some volatile essential oils of commonly used culinary herbs, spices and herbal teas have also exhibited a high level of antiviral activity. However, given the few classes of compounds investigated, most of the pharmacopoeia of compounds in medicinal plants with antiviral activity is still not known. Several of these phytochemicals have complementary and overlapping mechanisms of action, including antiviral effects by either inhibiting the formation of viral DNA or RNA or inhibiting the activity of viral reproduction. Assay methods to determine antiviral activity include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and post-treatment analyses. Methods are needed to link antiviral efficacy/potency- and laboratory-based research. Nevertheless, the relative success achieved recently using medicinal plant/herb extracts of various species that are capable of acting therapeutically in various viral infections has raised optimism about the future of phyto-antiviral agents. As this review illustrates, there are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse viruses families such as Retroviridae, Hepadnaviridae and Herpesviridae
Driving risk varies substantially according to many factors related to the driven vehicle, environmental conditions, and drivers. This study explores the contributing historical factors of driving ...risk with hierarchical clustering analysis and the quasi-Poisson regression model. The dataset of the study was collected from two sources: naturalistic driving experiments and self-reports. The drivers who participated in the naturalistic driving experiment were categorized into four risk groups according to their near-crash frequency with the hierarchical clustering method. Moreover, a quasi-Poisson model was used to identify the essential factors of individual driving risk. The findings of this study indicated that historical driving factors have substantial impacts on individual risk of drivers. These factors include the total number of miles driven, the driver's age, the number of illegal parking (past three years), the number of over-speeding (past three years) and passing red lights (past three years). The outcome of the study can help transportation officials, educators, and researchers to consider the influencing factors on individual driving risk and can give insights and provide suggestions to improve driving safety.
Mathematics teachers must be able to engage in self-reflection and think constructively about their professional activities to instruct students effectively. This is also important for students' ...ability to solve problems in class, as well as the challenges facing them and their societies in the future. This study aimed to examine in-service math teachers' reflective thinking skills in the context of how they are applied to their understanding of their teaching practices. The sample included 322 mathematics teachers, who responded to a questionnaire designed to elucidate how they were thinking reflectively about their teaching practice. The findings revealed that the teachers' practices concerning all the themes of reflective thinking addressed by the questionnaire, especially their ability to self-assess, fluctuated around the intermediate, and advanced levels. The implications of our findings are discussed in terms of extensive and continuous professional development centered on supporting ongoing growth in the reflective thinking skills of in-service math teachers.
Recently, hyperspectral image (HSI) classification has become a hot topic in the geographical images research area. Sufficient samples are required for image classes to properly train classification ...models. However, a class imbalance problem has emerged in hyperspectral image (HSI) datasets as some classes do not have enough samples for training, and some classes have many samples. Therefore, the performance of classifiers is likely to be biased toward the classes with the largest samples, and this can lead to a decrease in the classification accuracy. Therefore, a new deep-learning-based model is proposed for hyperspectral images generation and classification of imbalanced data. Firstly, the spectral features are extracted by a 1D convolutional neural network, whereas a 2D convolutional neural network extracts the spatial features and the extracted spatial features and spectral features are catenated into a stacked spatial–spectral feature vector. Secondly, an autoencoder model was developed to generate synthetic images for minority classes, and the image samples were balanced. The GAN model is applied to determine the synthetic images from the real ones and then enhancing the classification performance. Finally, the balanced datasets are fed to a 2D CNN model for performing classification and validating the efficiency of the proposed model. Our model and the state-of-the-art classifiers are evaluated by four open-access HSI datasets. The results showed that the proposed approach can generate better quality samples for rebalancing datasets, which in turn noticeably enhances the classification performance compared to the existing classification models.
The current study focuses on the effects of Cucumber mosaic virus (CMV) infection on phytochemical changes and pathogenesis- and phenylpropanoid pathway-associated gene activities in squash ...(Cucurbita pepo L.) plants during a time course of 2 to 12 days post inoculation (dpi). The identity of the CMV isolate was confirmed by DAS-ELISA, TEM, and coat protein gene sequence. The CMV infection initially boosts and then suppresses transcript levels of the defense-related genes PR-1, PR-2, PAL, HQT, and CHS during the investigated time course compared to controls. The expression profile during the time-course study indicated that early, transient induction of PR-1 occurs during CMV infection, while CMV induced the expression of PR-2 in systemically infected squash tissues at all time points and suppressed the expression of PAL and HQT at 8-12 dpi. CHS transcript levels fluctuated between up- and down-regulation, but by 12 dpi, CHS expression reached its peak. The HPLC and GC–MS analyses of CMV-infected squash extracts revealed that different phenolic, flavonoid, and fatty acid compounds could be induced or suppressed upon CMV infection. In particular, CMV could suppress the synthesis of most phenolic compounds, specifically chlorogenic acid, possibly leading to the virus’s rapid spread.
PDF
