bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-energy Resistive Random Access Memory Devices with No Need for a Compliance Current
Authors: Xu Zedong , Yu Lina , Wu Yong , Dong Chang , Deng Ning , Xu Xiaoguang , Miao J. , Jiang Yong 
Published: May 2015

AbstractA novel resistive random access memory device is designed with SrTiO3/ La2/3Sr1/3MnO3 (LSMO)/MgAl2O4 (MAO)/Cu structure, in which metallic epitaxial LSMO is employed as the bottom electrode rather than traditional metal materials. In this device, the critical external compliance current is no longer necessary due to the high self-resistance of LSMO. The LMSO bottom electrode can act as a series resistor to offer a compliance current during the set process. Besides, the device also has excellent switching features which are originated in the formation of Cu filaments under external voltage. Therefore it provides the possibility of reducing power consumption and accelerating the commercialization of resistive switching devices.
Dynastat frequency divider with DC‐153 GHz range
Authors: Vera L. , Long J.R. 
Published: May 2015

A dual‐mode dynamic/static (dynastat) divided‐by‐two combines the range of a static frequency divider (DC‐117 GHz from simulation) and the higher toggle frequency of a dynamic divider (85–153 GHz, simulated) at a low input sensitivity of 0.2 Vpk differential (<−3 dBm into 50 Ω). The measured self‐oscillation frequencies of the prototype are 79 GHz (static) and 129 GHz in dynamic mode. The 8880 μm2 dynastat implemented in 90 nm silicon germanium (SiGe)‐bipolar CMOS consumes 38 mA (static) and 19 mA (in dynamic mode) from a 4.5 V supply.
Swing‐programmable SST transmitter with power‐efficient de‐emphasis
Authors: Tang Liangxiao , Gai Weixin , Liu Jincai 
Published: May 2015

A novel 10 Gbit/s source‐series‐terminated (SST) transmitter in 65 nm CMOS technology is presented. Different from the conventional SST transmitter with the swing fixed to the supply voltage, the proposed transmitter, employing modified SST topology with switch‐based shunting legs, achieves tunable swing to provide suitable a output voltage for specific channel loss, resulting in higher power efficiency for the short and medium‐length channel. The proposed de‐emphasis scheme operates with the shunting path connecting the differential output pins instead of the voltage supply and the ground, which is more efficient than the conventional way. Fewer slices for de‐emphasis are needed along with less parasitic capacitance, and thus the power efficiency is improved. A full‐rate delay‐matching pre‐driver is used to avoid a complicated structure. Swing ranges from 50 mV to 1.2 V at a 1.2 V supply. The de‐emphasis could be tuned from 0 to −15.5 dB with power consumption dropping from 15.6 to 13.3 mW at the nominal swing of 1.2 V.
Design of absorptive frequency selective surface with good transmission at high frequency
Authors: Chen Qiang , Chen Liang , Bai Jiajun , Fu Yunqi 
Published: May 2015

An absorptive frequency selective surface with a wide absorptive property over the low band and a good transmissive property at high frequency is designed. The transmission of high frequency is realised by putting a choke structure into the element to control the current distribution. Its −10 dB absorption band is from 2.8 to 8.3 GHz and the transmission band is at 9.7 GHz with insertion loss <0.5 dB. Numerical and experimental results are given.
Constant on time controlled zero voltage switching electronic ballast with power quality improvement
Authors: Shrivastava Ashish , Singh Bhim 
Published: May 2015

This study deals with the design, modelling and implementation of unity power factor (UPF) boundary conduction mode (BCM)‐based electronic ballast for a T8, 36 W fluorescent lamp. In low power applications, BCM‐based boost converter is widely used because of the low inductor value, however, because of zero crossover distortion, achieving a total harmonic distortion of <10% is difficult for universal AC mains. In proposed electronic ballast, UPF has been achieved at universal AC mains by using a boost power factor corrected converter operating in BCM with constant on time control. The achieved constant DC‐link voltage is converted into high frequency AC voltage using a quasi‐half bridge series resonant inverter to initiate the discharge and also to drive the fluorescent lamp with constant current. The modelling and simulation of the proposed topology have been performed using sim power system tool‐boxes in MATLAB‐Simulink environment. The switching losses have been reduced by achieving zero voltage switching at an operating switching frequency of 46 kHz. Different evaluated parameters have been found as per the international standard IEC61000‐3‐2 of class C regulations.
A Clinical Prediction Rule for Clinical Outcomes in Patients Undergoing Surgery for Degenerative Cervical Myelopathy: Analysis of an International AOSpine Prospective Multicenter Data Set of 743 Subjects
Authors: Fehlings Michael , Tetreault Lindsay , Cote Pierre , Kopjar Branko , Arnold Paul 
Published: May 2015

Introduction Knowledge of important clinical predictors of surgical outcome can provide decision support to surgeons and enable them to appropriately manage their patients' expectations. This study aims to determine the most important global clinical predictors of surgical outcome in patients undergoing surgery for CSM, based on data from two multicenter prospective studies. Patients and Methods A total of 743 surgical patients with CSM participated in either the CSM-North America or CSM-International study. The model was developed to distinguish between patients with mild myelopathy postoperatively (mJOA ≥ 16) and those with substantial residual neurological impairment (mJOA < 16). Univariate analyses were performed to evaluate the relationship between outcome and various clinical predictors. Multivariate logistic regression was used to formulate the final prediction model. Results Univariate analyses demonstrated that the odds of achieving a score ≥ 16 decreased with the presence of certain symptoms, including impaired gait; the presence of certain signs such as lower limb spasticity; positive smoking status; a higher comorbidity score; more severe preoperative myelopathy; and older age. The final prediction model included age (OR = 0.97, p = 0.0017), duration of symptoms (OR = 0.88, p = 0.049), smoking status (OR = 0.51, p = 0.0018), impairment of gait (OR = 1.94, p = 0.0168), broad-based unstable gait (OR = 1.75, p = 0.0133), baseline severity (OR = 1.23, p < 0.0001), and comorbidity score (OR = 0.84, p = 0.0030). Conclusion Patients are more likely to achieve a score ≥ 16 if they are younger, have a shorter duration of symptoms, are less severe preoperatively, do not smoke, and do not have comorbidities or evidence of gait dysfunction.
Which Factors Predict Shoulder Asymmetry in Patients with Lenke Type 1 and 3 Curves following Pedicle Screw Instrumentation?
Authors: Enercan Meric , Kahraman Sinan , Gokcen Bahadir , Sanli Tunay , Ozturk Cagatay , Talu Ufuk , Alanay Ahmet , Hamzaoglu Azmi 
Published: May 2015

Introduction Shoulder asymmetry (SA) has been reported to be a frequent (39%) problem after fusion of the main thoracic (MT) curve in patients with nonstructural proximal thoracic (PT) curves (Lenke Type 1 and 3). The purpose of this study was to analyze factors related to shoulder asymmetry and efficacy of traction X-ray under general anesthesia (TrUGA) in predicting postoperative shoulder asymmetry. Material and Methods A total of 137 (128 female patients, 9 male patients) consecutive patients (average age: 14.2 [11–17]) with Lenke Type 1 and Type 3 curves and preoperative right shoulder elevation (RSE) with (-) T1 tilt were included in this study. Radiographic analysis included preoperative, postoperative, and follow-up AP standing, supine bending, and TrUGA. Magnitudes of curves, T1 tilt, clavicle angle, shoulder height, first rib angle (FRA), and second rib angles (SRA) were measured as shoulder asymmetry parameters. Left or right shoulder elevation > 1 cm is accepted as shoulder imbalance. SRS-22r and shoulder balance questionnaires were also analyzed at follow-up. Results Mean age was 13.96 years (11–17) and average follow-up was 5.21 years (2–12). A total of 107 patients had UIV at T2, 17 patients had UIV at T3, and 13 had UIV at T4. Average correction rates were 69.12% for PT curve, 82.4% for MT curve, and 73.5% for TL/L curve. Postoperatively, 101 patients (73%) had balanced shoulders. A total of 17 patients (12.4%) had LSE and 20 patients (14.6%) had RSE postoperatively. Incidence of LSE was 8.4% (9 patients) for UIV at T2, 29.4% (5 patients) for UIV at T3, and 23.1% (3 patients) UIV at T4. Higher percentage of MT correction was correlated with LSE ( p = 0.043). Shoulder height, clavicula angle, T1 tilt, FRA, and SRA were correlated in TrUGA and at follow-up. Preoperatively, 83% of the patients and at final follow-up 7.8% patients thought they had shoulder asymmetry. Av SRS-22r score was 4.32 (2, 96–5) and was similar in patients who had shoulder asymmetry (4, 36) versus no asymmetry (4, 29). Conclusion Risk factors for shoulder asymmetry in patients with nonstructural PT curves are higher correction percentage of MT and extension of instrumentation up to T3 at PT curve. Extension of fusion up to T2 did not always prevent shoulder asymmetry in patients with nonstructural PT curves. Shoulder asymmetry parameters in TrUGA are helpful in predicting postoperative shoulder asymmetry. HRQL scores are similar in patients with SA versus no SA.
International Classification and Function used in a Rehabilitation Program of Low Back Pain Patients
Authors: Schiottz-Christensen Berit 
Published: May 2015

Introduction ICF is developed as a generic system for classification of function. The ICF framework is often used to describe functional capacity of the low back patient (LBP) referred for rehabilitation but the score describing the level of capacity for the individual patient is not used in daily practice. The purpose of the presented study was to implement and validate the core set for LBP used as a framework for reporting information and to evaluate whether information reported in self-administered questionnaires (PRMOs) can be used to fill in parts of the ICF. Patients and Methods LBP referred to the University Hospital, Aarhus, Denmark, for further diagnostic procedures were included in the cohort. Overall, 80 patients were described according to the framework of ICF and scored according to the LBP brief core set.1 Of the whole group, 28 (35%) were referred to a rehabilitation center. At inclusion and at the rehabilitation center, the team treating the patient did the ICF scoring at inclusion and at 4 weeks' follow-up. In addition, the patients filled in questionnaires; Roland Morris and SF-36. The correlation between the registration in the context of ICF at one side and RM/SF-36 at the other was estimated to validate whether a self-administered questionnaire is as valid to describe functional capacity as an interview by the treating physician. Results The functional capacity evaluated by the treating team at first gradient for each of 35 domains in ICF correlated with information obtained from the self-administered questionnaires RM and SF-36. Valid information can be translated from RM and SF-36 and the time used to complete the ICF form can be reduced. A dynamic model describing the functional capacity of the individual patient in the terms of ICF filled in by self-administered questionnaires will be demonstrated and the need of supplementary information obtained by interview will be highlighted. Conclusion ICF can be used as a framework for information used in a rehabilitation program. The corset has to be defined in detail, as well as the approach to the scoring system, before the information given is reliable as well as clinical important in any clinical setting. PROMs can be used to fill in part of the ICF core set. A dynamic database is a valuable tool facilitating the reporting process. Reference Stucki G, Ewert T, Cieza A. Value and application of the ICF in rehabilitation medicine. Disabil Rehabil 2002;24(17):932–938
Association of Lumbar Spondylolisthesis with Low Back Pain and Symptomatic Lumbar Spinal Stenosis in a Population-Based Cohort: The Wakayama Spine Study
Authors: Ishimoto Yuyu 
Published: May 2015

Introduction Despite the high number of surgeries performed for spondylolisthesis, the basic epidemiology of lumbar spondylolisthesis in the general population is not well known. The aim of this study was to clarify the association of lumbar spondylolisthesis with symptomatic lumbar spinal stenosis (LSS) in a population-based cohort study with participants representing the general Japanese population. Patients and Methods This cross-sectional study included 938 participants (308 men, 630 women; mean age, 67.3 years; range, 40–93 years). Lumbar radiographs were obtained for all the participants, with lumbar spondylolisthesis classified as a slip of more than 5% on the lateral view. The diagnosis for symptomatic LSS required the presence of both leg symptoms and radiographic lumbar spinal stenosis on magnetic resonance imaging. The presence of symptomatic LSS was compared between participants with and those without lumbar spondylolisthesis using statistical analysis. Furthermore, we clarified the association between the amount of slippage and the presence of neurogenic claudication. Results The prevalence of spondylolisthesis at any level was 15.8% overall, 13.0% in men and 17.1% in women, with no significant difference between genders. The prevalence of symptomatic LSS was 9.0% overall, 9.4% in men, and 8.7% in women. Logistic regression analysis after adjustment for age, gender, and BMI showed that there existed a significant association of spondylolisthesis with symptomatic LSS overall. (OR: 2.07, 95% CI: 1.20–3.44). While, among participants with L4 anterior spondylolisthesis, the mean percentage slip in those with neurogenic claudication was 14 ± 1.2% and those without was 14 ± 0.5%, with no significant difference. Conclusion This population-based cohort study revealed that there was a significant association of spondylolisthesis with neurogenic claudication, although the amount of slippage was not related to the presence of neurogenic claudication.
Economic Evaluation of Intraoperative Cone Beam CT-Based Navigation for the Placement of Spinal Pedicle Screws: A Patient Level Cost Effectiveness Analysis
Authors: Dea Nicolas , Fisher Charles , Batke Juliet , Street John 
Published: May 2015

Introduction Pedicle screws are routinely used in contemporary spinal surgery. Screw misplacement is however correlated with potential adverse events. The goal of this study is to perform an economic evaluation looking specifically at the misplaced screws leading to reoperation secondary to neurological deficits or biomechanical concerns. Material and Methods A patient-level data cost-effectiveness analysis from the hospital perspective was conducted based on a single center observational study of prospectively collected data to determine the value of a navigation system coupled with intraoperative 3D imaging (O-arm Imaging and the StealthStation S7 Navigation Systems, Medtronic, Louisville, CO) in adult spinal surgery. The data source was a consecutive series of patients treated with the aid of computer-assisted surgery (treatment group) compared with a matched historical cohort of patients treated with conventional methods (control group). The primary effectiveness measure studied was the number of reoperations for misplaced screws. Results A total of 5,132 pedicle screws were inserted in 502 patients during the study period; 2,682 screws in 253 patients in the treatment group, and 2,450 screws in 249 patients in the control group. Overall accuracy rates were 95.2% for the treatment group and 86.9% for the control group. Two patients (0.8%) required a revision surgery in the treatment group (both within the same admission) compared with 15 patients (6%) in the control group (nine within the same admission and six within 1 year during a subsequent admission). Costs of the different alternatives were assessed based on the annuitization of capital expenditures method. Using this methodology, an incremental cost effectiveness ratio of $15,961/reoperation avoided was calculated for the computer-assisted surgery group. On the basis of a reoperation cost of $12,618, this new technology becomes cost saving for centers performing more than 254 instrumented spinal procedures per year. Conclusion Computer-assisted spinal surgery has the potential to reduce reoperation rates and thus to have serious cost-effectiveness implications. High acquisition and maintenance costs of this technology can be offset by equally high reoperation costs. Our cost-effectiveness analysis showed that for high-volume centers, this technology is economically justified.
Quantitative Magnetic Resonance Imaging Analysis of the Cervical Spine Extensor Muscles: A Pilot Study
Authors: Fortin Maryse , Dobrescu Octavian , Ouellet Jean , Weber Michael 
Published: May 2015

Introduction Variations in cervical muscle cross-sectional area (CSA) and composition, particularly of the multifidus muscle, have been reported in patients with chronic neck pain. However, few studies have reported on the reliability of such muscle measurements and there remains no standard protocol for tissue segmentation. Therefore, the purpose of this pilot study was to provide a detailed muscle measurement protocol and determine the reliability of associated cervical muscle size and composition measurements using an open-source image analysis software (ImageJ). Material and Methods Cervical magnetic resonance images of 10 individuals with spinal stenosis were selected from an internal database. Muscle CSA and functional cross-sectional area (FCSA, fat-free area) measurements of the multifidus, semispinalis cervicis, semispinalis capitis, and splenius capitis were acquired bilaterally from axial T2-weighted magnetic resonance image from C2–C3 to C6–C7 levels. All measurements were repeated twice, at least 5 days apart and the assessor was blinded to all earlier measurements. Results The reliability for the upper (C2–C3 and C3–C4) and lower cervical levels (C4–C5, C5–C6, and C6–C7) was assessed separately. The intrarater reliability measurements were comparable between muscles and spinal levels. The intraclass correlation coefficient (ICC) for the CSA measurements varied between 0.79 to 0.97 at C2–C4 and 0.75 to 0.91 at C4–C7. The reliability was similar for the FCSA measurements and varied between 0.73 to 0.93 at C2–C4 and 0.78 to 0.90 at C4–C7. Conclusion The results of this pilot study suggest that the proposed method to investigate cervical muscle size and composition is reliable, with moderate-to-excellent reliability across cervical muscles and vertebral levels.
Economic Evaluation of Lumbar Disc Herniation Surgery in Brazilian Health
Authors: Falavigna Asdrubal , Teles Alisson Roberto , Righesso Orlando , Gollo Maria Carolina Rosa , Scheverin Nicolas , Cheng Joseph S. , Riew K. Daniel 
Published: May 2015

Introduction Lumbar discectomy is one of the most common surgical procedures, with success rates greater than 80%. To better understand the meaning of a good outcome in lumbar disc herniation treatment, it is important to know how much the health care system or the patient need to pay to achieve a good result. The cost–utility studies are useful to evaluate the value of health care interventions. The objective of this study was to evaluate for the first time the cost-effectiveness of spine surgery in Latin America for lumbar discectomy in terms of cost per quality-adjusted life years (QALY) gained in Brazil. Patients and Methods Costs of medical treatment were recorded in 143 consecutive patients who underwent open discectomy for lumbar disc herniation. Direct medical costs comprised medical reimbursement and costs of hospitalization. Indirect costs were considered the disability losses. Utilities were estimated using SF-6D–derived utilities from a 12-month variation in SF-36. A 4-year horizon with 3% discounting was applied to health utilities estimates. Sensitivity analysis was performed by varying utility gain by 20%. The costs were expressed in Reais (R$) and American Dollars ($), at an exchange rate of 2.4:1. Results Direct and indirect costs of open discectomy were estimated at an average of R$ 3.426,72 ($ 1,427.80) and R$ 2.027,67 ($ 844.86), respectively. The mean total cost of treatment was estimated at R$ 5.454,40 ($ 2,272.66) (± R$ 2.709,17/$ 1,128.82) The SF-6D utility gain was 0.0456 (95% CI: 0.03197–0.05923, p = 0.017) at 12 months. The 4-year discounted QALY gain was 0.176928. The estimated cost-utility ratio was R$ 30.828,35 ($ 12,845.14) per QALY gained. The sensitivity analysis showed a range of R$ 25.690,29 ($ 10,714.28)–R$ 38.535,44 ($ 16,056.43) per QALY gained. Conclusion Open discectomy is associated with a significant improvement in health utilities as measured by SF-6D. Open discectomy performed in the Brazilian Supplementary Health System provides a cost–utility ratio of R$ 30.828,35 ($ 12,845.14) per 1 quality-adjusted life year.
Reliability of Postoperative Multislice Computed Tomography in Assessment of Pedicle Screw Placement in Thoracic and Lumbar Spinal Fixation
Authors: Awadalla Akram , El Fiki Inas , Fatma Zaiton 
Published: May 2015

Objective This study aims to evaluate the reliability of three-dimensional (3D) volume rendering computed tomography (CT) in postoperative assessment of pedicle screw placement. Methods A total of 98 patients with previous spinal fixation surgery were included. All inserted screws were evaluated postoperatively within the first week using CT. Degree of misplacement and difference between CT images were recorded. Results Overall, 76, 68, and 39 misplaced screws were detected in 3D reformatted image, coronal reconstruction, and axial CT images, respectively. Dorsal spine had higher rate of violation 46 (9.95%) with the highest rate at T4 (12.8%) comparing it with lumber 32 (6.9%). Statistically significant differences were found between lateral and medial violation ( p = 0.03), between findings of CT 3D reformatted and axial image ( p = 0.04), and also in detecting end plate perforation and anterior vertebral encroachment in different CT images ( p = 0.013). Sensitivity for 3D reformatted image and axial image compared with surgical finding in six revised screws was 100 and 95.8% and specificity 100 and 88.7%, respectively. Highly momentous agreement reported with Kappa coefficient = 0.95 Â ± < 0.001. Conclusion The vertebral body and the pedicle are 3D structures. Therefore, we have to study them as they are. The postoperative evaluation of pedicle screw using CT 3D reconstruction was a reliable method and unveiled the deficiencies in conventional axial CT.