Long-term outcome of posterior spinal fusion for the correction of adolescent idiopathic scoliosis

Background: Adolescent idiopathic scoliosis (AIS) is the most common form of idiopathic scoliosis, and surgery is considered as one of the therapeutic options. However, it is associated with a variety of irreversible complications, in spite of the benefits it provides. Here, we evaluated the long-term outcome of posterior spinal fusion (PSF) of AIS to shed more light on the consequences of this surgery. Methods: In a cross-sectional study, a total of 42 AIS patients who underwent PSF surgery were radiographically and clinically inspected for the potential post-operative complications. Radiographic assessments included the device failure, union status, and vertebral tilt below the site of fusion. Clinical outcomes were evaluated using the Oswestry disability index (ODI) and visual analogue scale (VAS). Results: The mean age of the surgery was 14.4 ± 5.1 years. The mean follow-up of the patients was 5.6 ± 3.2 years. Complete union was observed in all patients, and no device failure was noticed. Pre- and post-operative vertebral tilt below the site of fusion were 11.12° ± 7.92° and 6.21° ± 5.73°, respectively (p < 0.001). The mean post-operative ODI was 16.7 ± 9.8. The mean post-operative VAS was 2.1 ± 0.7. ODI value was positively correlated with follow-up periods (p = 0.04, r = 0.471). New degenerative disc disease (DDD) was observed in 6 out of 37 (16) patients. Conclusion: In spite of the efficacy and safety of PSF surgery of AIS, it might result in irreversible complications such as DDD. Moreover, the amount of post-operative disability might increase over the time and should be discussed with the patients. © 2018 The Author(s)

Management of spine trauma in COVID-19 pandemic: A preliminary report

Background: COVID-19 was first identified in Iran in February 2020 and since then it spread rapidly through all over the country and soon after that it was reported as a pandemic. The current study presents a preliminary report of spine trauma management during COVID-19 pandemic. Methods: A cross sectional study was designed to evaluate patients admitted for vertebral fractures with diagnosis of COVID-19 infection on February and March 2020. Analysis was made based on clinical and laboratory data along with the imaging findings from chest HRCT. Results: Seven patients with spine trauma including five males and two females ranging from 14 to 59 years were diagnosed for COVID-19 infection through CT-scan findings. Except one, all other patients were asymptomatic for COVID-19 at the time of admission. In three cases the COVID diagnosis was made the day after arrival and in others after 10, 14 and 35 days. Five patients were treated surgically among whom four were admitted to ICU soon after the surgery. The mean ICU stay for operated patients were eight days and the mean hospital stay was 22.6 days. Conclusion: Proper diagnosis of COVID-19 is the keystone to protect both patients and health care providers. During the pandemic all admitted patients should be screened for COVID-19 infection. Unnecessary procedures for spine trauma patients should be avoided in order to reduce complications related to surgery and to preserve ICU beds. © 2020 BY THE ARCHIVES OF BONE AND JOINT SURGERY

COVID-19 among patients with orthopedic surgery: our experience from the Middle East

Background: We report our experiences with COVID-19 in one of the largest referral orthopedic centers in the Middle East and aimed to describe the epidemiology and clinical characteristics of these patients. Methods: During February 20 and April 20, 2020, patients who underwent orthopedic surgery and healthcare staff who were in contact with these patients were screened for COVID-19. To identify patients who were in the incubation period of COVID-19 during their hospital stay, all patients were tested again for COVID-19 4 weeks after discharge. Results: Overall, 1244 patients underwent orthopedic surgery (1123 emergency and 121 elective) during the study period. Overall, 17 patients were diagnosed with COVID-19 during hospital admission and seven after discharge. Among the total 24 patients with COVID-19, 15 were (62.5) males with a mean (SD) age of 47.0±1.6 years old. Emergency surgeries were performed in 20 (83.3) patients, and elective surgery was done in the remaining 4 patients which included one case of posterior spinal fusion, spondylolisthesis, acromioclavicular joint dislocation, and one case of leg necrosis. A considerable number of infections occurred in patients with intertrochanteric fractures (n=7, 29.2), followed by pelvic fractures (n=2, 8.3), humerus fractures (n=2, 8.3), and tibial plateau fractures (n=2, 8.3). Fever (n=11, 45.8) and cough (n=10, 37.5) were the most common symptoms among patients. Laboratory examinations showed leukopenia in 2 patients (8.3) and lymphopenia in 4 (16.7) patients. One patient with a history of cancer died 2 weeks after discharge due to myocardial infarction. Among hospital staff, 26 individuals contracted COVID-19 during the study period, which included 13 (50) males. Physicians were the most commonly infected group (n = 11), followed by operation room technicians (n = 5), nurses (n = 4), and paramedics (n = 4). Conclusions: Patients who undergo surgical treatment for orthopedic problems, particularly lower limb fractures with limited ambulation, are at a higher risk of acquiring COVID-19 infections, although they may not be at higher risks for death compared to the general population. Orthopedic surgeons in particular and other hospital staff who are in close contact with these patients must be adequately trained and given appropriate personal protective equipment during the COVID-19 outbreak. © 2021, The Author(s)

Control Lyapunov Functions: A Control Strategy for Damping of Power Oscillations in Large Power Systems

Keywords: Controllable Series Devices (CSDs), Unified Power Flow Controller (UPFC), Quadrature Boosting Transformer (QBT), Controllable Series Capacitor (CSC), Lyapunov function, Control Lyapunov Function (CLF), Single Machine Equivalent (SIME), Variable Structure Control (VSC)

Title:Evaluation of Optimal Water Allocation Scenarios for Bar River of NeishabourUsing WEAP Model Under A2 Climatic Changes Scenario

Introduction: The rapid population growth in Iran and the corresponding increases in water demands, including drinking water, industry, agriculture and urban development and existing constraints necessitate optimal scheduling necessity in use of this crucial source. Furthermore, the phenomenon of climate change as a major challenge for humanity can be considered in future periods. Climate change is caused by human activity have also been identified as significant causes of recent climate change, referred to as "global warming". Climate change indicates an unusual change in the Earth's atmosphere and climate consequences of the different parts of planet Earth. Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions. A Warmer climate exacerbates the hydrologic cycle, altering precipitation, magnitude and timing of runoff. The purpose of this study was to evaluate the effect of climate change on water consumption and demand in Bar river basin of Neighbor. Climate change affects precipitation and temperature patterns and hence, may alter on water requirements and demand at three sectors; agriculture, industry and urban water. Materials and Methods: At present, Global coupled atmosphere-ocean general circulation models (AOGCMs) are the most frequently used models for projection of different climatic change scenarios. AOGCMs models represent the pinnacle of complexity in climate models and internalize as many processes as possible. These models are based on physical laws that are provided by mathematical relations. AOGCMs models used for climate studies and climate forecast are run at coarse spatial resolution and are unable to resolve important sub-grid scale features such as clouds and topography. As a result AOGCMs output cannot be used for local impact studies. Therefore, downscaling methods were developed to obtain local-scale weather and climate, particularly at the surface level, from regional-scale atmospheric variables that are provided by AOGCMs. Four different downscaling methods exist: regression methods, weather pattern-based approaches, stochastic weather generators, which are all statistical downscaling methods, and limited-area modeling. For this research, HadCM3 and statistical downscaling model (SDSM), precipitation and temperature variations were simulated under A2 scenario. Then the impacts of these variations on Bar River discharge were analyzed, i.e. water resources at three sectors of agriculture, industrial and potable water under climate change during 2011-2040 using WEAP. Results at first part of simulation showed that temperature is increasing and precipitation is decreasing resulted in decreasing of Bar discharge. According to the decreasing on Bar discharge, water allocation was simulated under these conditions of agricultural and industrial development and increasing of population with WEAP. Simulation showed that watershed will face increasing of water demand for all three sectors; agriculture, industry and drinking water, so the highest water shortage would be in agricultural demand and then industry and drinking water respectively. IWRM is the basic managerial need to rest the demands especially for drought periods. Current allocation process is based on steady state conditions while allocation pattern would be done under climate change conditions so we need to be reinvestigat the last allocations for all three sectors. Another challenge for this watershed refers to the gardens and steel factory of Khorasan that they need to use new technologies for reduction of their water needs. Results Discussion: In this study, the outputs of General Circulation Models (HadCM3) and statistical downscaling model (SDSM) have been used to investigate the changes of rainfall and temperature under A2 scenario in Bar river basin of Neishaboor and assess the impacts of this changes on the Bar river’s discharge. Finally, using WEAP model under climate change conditions for the period of 2011-2040, the status of basin water resources was evaluated for the three sectors (agricultural, domestic and industrial). The results indicated increased temperature in the Arie station amounting to 16 percent and rainfall reduction in the Arie and Taghan stations amounting to 3.9 and 8.75 percent respectively. Under these conditions, according to the increasing water demands of agricultural and industrial sectors in the future, there will be a shortage of water supply resources in the region. So the agricultural sector with 12 percent will have the highest percentage of water shortage and water scarcity and of the industrial sector will be 2%. However, the drinking water or domestic demand will not face a shortage of supplies. Conclusion: Therefore given that the most part of agriculture sector’s share of basin is allocated to orchards and on the other hand the most shortages are related to agriculture, then while creating an integrated management of water resources, development and use of modern methods of irrigation during the period of 2011 - 2040 would seem to be necessary

A control strategy for controllable series capacitor in electric power systems

It has been veri"ed that a controllable series capacitor with a suitable control scheme can improve transient stability and help to damp electromechanical oscillations. A question of great importance is the selection of the input signals and a control strategy for this device in order to damp power oscillations in an e!ective and robust manner. Based on Lyapunov theory a control strategy for damping of electromechanical power oscillations in a multi-machine power system is derived. Lyapunov theory deals with dynamical systems without inputs. For this reason, it has traditionally been applied only to closed-loop control systems, that is, systems for which the input has been eliminated through the substitution of a predetermined feedback control. However, in this paper, we use Lyapunov function candidates in feedback design itself by making the Lyapunov derivative negative when choosing the control. This control strategy is called control Lyapunov function for systems with control inputs. Also, two input signals for this control strategy are used. The "rst one is based on local information and the second one on remote information derived by the single machine equivalent method

Different kinds of embodied language: A comparison between Italian and Persian languages

It is debated whether only concrete but also abstract, figurative sentences, e.g.: “She grasps the cup” vs. “She grasps the concept”, are grounded in the sensorimotor system. Importantly, studies on sentences with action verbs and motor system activation have been conducted so far only with WEIRD samples (Western cultures, in North American and European countries). The aim of our work is to investigate the relationship between language and motor responses using both concrete and abstract sentences in Italian and Persian languages. In the present study, Italian and Persian participants were asked to read the sentences on the screen. The sentences referred either literally or metaphorically to motor actions. They were accompanied by a video displaying a movement that could be congruent or incongruent with the one described in the sentence. Participants were asked to re-execute the movement observed and subsequently they had to perform the task evaluating whether the sentence made sense or not. In the Italian sample a strong effect of concreteness was present, especially in the congruent but also in the incongruent condition. In the Persian sample, instead, there was an inhibition effect of congruent trials, particularly with concrete sentences, and in the incongruent trials no difference in RTs between abstract and concrete sentences was present. Results indicate that cross-cultural differences have to be taken into account when investigating the relationship between language and action

Assessment of disability levels in patients with low back pain based on the type of lumbar spinal disorder

BACKGROUND: Low back pain (LBP) is a common health condition and the leading cause of activity limitation and absenteeism in most parts of the world. One-fifth of patients with LBP develop chronic pain disability. OBJECTIVE: This study investigated the disability levels in patients with different types of lumbar spinal disorders. METHODS: A total of 528 patients visiting spine clinics between June 2017 and February 2018 were enrolled in this study. A demographic checklist, the patients' medical records, the Oswestry Disability Questionnaire, and the Visual Analog Scale (VAS) were used to collect the data. RESULTS: Non-specific LBP (29.5) and discopathy (27) were the most common final diagnoses. The obtained Oswestry Disability Index (ODI) was significantly higher in older patients, those with higher body mass index, more work experience, and smokers. Lower ODI was found in individuals with a history of regular exercise. Most individuals in all diagnostic groups were categorized into the high ODI group (p⩽ 0.001). CONCLUSION: In patients with lumbar spine lesions, ODI is significantly correlated with age, BMI, work experience, smoking, and the type of disorder (discopathy, spondylolysis, and spondylolisthesis). Regular exercise is associated with lower levels of disability

Reduced-order modelling of wind turbines

In this chapter power system dynamics simulation(PSDS) isused to study the dynamics of large-scale power systems. It is necessary to incorporate models of wind turbine generating systems into PSDS software packages in order to analyse the impact of high wind power penetration on electrical power systems. These models need to match the assumptions and simplifications applied in this type of simulation. This chapter presents models that can be used to represent wind turbines in PSDSs. We give a brief introduction to PSDS, and describe the three main wind turbine types and the assumptions on which they are modelled. We then present the models of the various subsystems of each of the most important current wind turbine types are then presented. The response of the models to a simulated wind speed sequence is then shown