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The past few decades have seen the rapid development of topic modeling. So far, research has been more concerned with determining the ideal number of topics or meaningful topic clustering words than with applying topic modeling techniques to evaluate linguistic theories. This study proposes the Structural Topic Model (STM)-led framework to facilitate the interpretation of topic modeling results and standardize text analysis. STM encompasses various model training mechanisms, thereby requiring systematic designs to properly combine language studies. “Structural” in STM refers to the inclusion of metadata structure. Unlike the corpus-based keyness approach, STM can capture contextual cues and meta-information for the interpretation of topical results. Besides, STM can make cross-corpora comparisons via topical contrast, a challenging task for corpus-driven related models such as the Biterm Topic Model (BTM). Stylistic variations in song lyrics are taken as an illustration to show how to use the suggested framework to delve into the linguistic theory proposed by Pennebaker (2013). The topical model and iterable model in the proposed paradigm can clarify how pronouns affect style distinction. We believe the proposed STM-led framework can shed light on text analysis by conducting a reproducible cross-corpora comparison on short texts.

Pedicle screw-rod assembly procedures following pedicle screw insertion include contouring and placing rods into screw tulips, introducing set screws into the tulip along the screw thread, applying a counter-torque holder and tightening all the set screws clockwise. Even if an appropriate pedicle screw is implanted, screw dislodgement after tightening of the tulip and set screw is not uncommon. Pedicle wall violation resulting from excessive rotational force due to inadequate use of a counter-torque holder might be the reason. However, the strain change in the pedicle during tulip-set screw tightening and the role of counter-torque have never been investigated.This study determined differences in the strain change in the outer and inner pedicle walls during tulip-set screw tightening; additionally, the influence of counter-torque on pedicle wall violation was elucidated.A controlled biomechanical study; the strain values of outer and inner pedicle walls in cadaveric porcine L4-L5 vertebrae during tulip-set screw tightening with or without a counter-torque holder were measured.Twelve L4-L5 fresh-frozen porcine lumbar vertebrae were implanted with screw-rod constructs; the set screw was randomly locked into the tulip in the right L5, right L4, left L5 and left L4 testing groups. The maximal values from eight strain gauges (P-R-O: outer cortex of right pedicle in proximal vertebra; P-R-I: inner cortex of right pedicle in proximal vertebra; D-R-O: outer cortex of right pedicle in distal vertebra; D-R-I: inner cortex of right pedicle in distal vertebra; P-L-O: outer cortex of left pedicle in proximal vertebra; P-L-I: inner cortex of left pedicle in proximal vertebra; D-L-O: outer cortex of left pedicle in distal vertebra; D-L-I: outer cortex of left pedicle in proximal vertebra) for each specimen during tightening to 12 Nm were measured.The maximal strain values of the ipsilateral strain gauges in all testing groups were almost significantly higher when a counter-torque holder was not used than when one was used. The strain values in the adjacent pedicle of specimens without a counter-torque holder were significantly increased: P-R-O and P-R-I in the right L5 group; D-R-I in the right L4 group; P-L-I and P-L-O in the left L5 group; D-L-O and D-L-I in the left L4 group.The constraint effect of counter-torque during tulip-set screw tightening is necessary. Clockwise rotational force with a fragile lateral pedicle wall suggests that caution is required when using a counter-torque holder to tighten the right L5 and left L4 constructs.A counter-torque holder is important during tulip-set screw tightening; improper use may lead to adjacent pedicle wall violation, sequentially resulting in pedicle screw loosening.

OBJECTIVE Decreased bone mineral density as measured by dual-energy x-ray absorptiometry (DEXA) has been reported to be associated with cage subsidence following transforaminal lumbar interbody fusion (TLIF). However, DEXA is not often available or routinely performed before surgery. A novel MRI-based vertebral bone quality (VBQ) score has been developed and reported to be correlated with DEXA T-scores. The authors investigated the ability of the VBQ score to predict cage subsidence and other risk factors associated with this complication. METHODS In this retrospective study, the authors reviewed the records of patients who had undergone single-level TLIF from March 2014 to October 2015 and had a follow-up of more than 2 years. Cage subsidence was measured as postoperative disc height loss and was graded according to the system proposed by Marchi et al. The MRI-based VBQ score was measured on T1-weighted images. Univariable analysis and multivariable binary logistic regression analysis were performed. Ad hoc analysis with receiver operating characteristic curve analysis was performed to assess the predictive ability of the significant continuous variables. Additional analyses were used to determine the correlations between the VBQ score and T-scores and between the significant continuous variables and the amount of cage subsidence. RESULTS Among 242 patients eligible for study inclusion, 111 (45.87%) had cage subsidence after the index operation. Multivariable logistic regression analyses demonstrated that an increased VBQ score (OR 14.615 ± 0.377, p < 0.001), decreased depth ratio (OR 0.011 ± 1.796, p = 0.013), and the use of kidney-shaped cages instead of bullet-shaped cages (OR 2.766 ± 0.358, p = 0.008) were associated with increased cage subsidence. The VBQ score was shown to significantly predict cage subsidence with an accuracy of 85.6%. The VBQ score was found to be moderately correlated with DEXA T-scores of the total hip (r = −0.540, p < 0.001) and the lumbar spine (r = −0.546, p < 0.001). The amount of cage subsidence was moderately correlated with the VBQ score (r = 0.512, p < 0.001). CONCLUSIONS Increased VBQ scores, posteriorly placed cages, and kidney-shaped cages were risk factors for cage subsidence. The VBQ score was shown to be a good predictor of cage subsidence, was moderately correlated with DEXA T-scores for the total hip and lumbar spine, and also had a moderate correlation with the amount of cage subsidence.

Intraoperative pedicle screw depth adjustment after initial insertion, including both forward and backward adjustments, is sometimes necessary to facilitate rod application and ensure that the screw is in the correct position, which is determined by intraoperative fluoroscopy. Adjusting the screw with forward turns has no negative influence on the screw fixation stability; however, screw turnback may weaken the fixation stability. The aim of this study is to evaluate the biomechanical properties of screw turnback and demonstrate the reduction in the fixation stability after the screw is turned 360° from its full insertion position. Commercially available synthetic closed-cell polyurethane foams with three different densities simulating various degrees of bone density were utilized as substitutes for human bone. Two different screw shapes (cylindrical and conical) together with two different pilot hole profiles (cylindrical and conical) were tested. Following specimen preparation, screw pullout tests were conducted using a material test machine. The mean maximal pullout strength between full insertion and 360-degree turnback from full insertion in each setting was statistically analyzed. The mean maximal pullout strength after 360-degree turnback from full insertion was generally lower than that at full insertion. The reduced mean maximal pullout strength after turnback increased with decreasing bone density. Conical screws had significantly lower pullout strength after 360-degree turnback than cylindrical screws. The mean maximal pullout strength was reduced by up to approximately 27% after 360-degree turnback when using a conical screw in a low bone density specimen. Additionally, specimens treated with a conical pilot hole presented a less reduction in pullout strength after screw turnback as compared to those with a cylindrical pilot hole. The strength of our study was that we systematically investigated the effects of various bone densities and screw shapes on screw stability after turnback, which has rarely been reported in the literature. Our study suggests that pedicle screw turnback after full insertion should be reduced in spinal surgeries, particularly procedures that use conical screws in osteoporotic bone. Pedicle screw secured with a conical pilot hole might be beneficial for screw adjustment.

Recurrent word sequences, referred to as “lexical bundles”, may be structurally incomplete, but they serve important communicative functions. Despite the essential roles of lexical bundles in discourse, many methodological issues have been raised in the process of identifying lexical bundles, which is generally frequency-based. The present study identifies three-word and four-word bundles in Chinese conversation and news, and efforts are made to respond to methodological challenges encountered in previous studies. We employ a more sensitive dispersion measure, DP, and an internal association measure, G, which help filter out high-frequency word sequences with no identifiable function and reduce the workload of further manual interventions. An exploratory data analysis is then conducted to compare the distributional patterns of lexical bundles in Chinese conversation and news. In Chinese, both the type number and the density of lexical bundles are higher in conversation than in news. This appears to be a strong cross-linguistic tendency that reflects the real-time pressure speakers face in spontaneous speech. The exploratory data analysis also shows that the elements in Chinese bundles are closely associated with each other. This suggests that lexical bundles are useful phrasal units in Chinese discourse, and thus invites further investigations of how lexical bundles are used in Chinese.

Although an anterior approach with anterior lateral screw fixation has been developed for stabilizing the thoracolumbar spine clinically, screw loosening still occurs. In this novel in vitro study, we attempted to elucidate the optimal screw position in the lateral lumbar vertebra and the effect of bicortical fixation. A total of 72 fresh-frozen lumbar vertebrae from L1–6 were harvested from 12 mature pigs and randomly assigned to two modalities: bicortical fixation (n = 36) and unicortical fixation (n = 36). Six groups of screw positions in the lateral vertebral body in each modality were designated as central-anterior, central-middle, central-posterior, lower-anterior, lower-middle, and lower- posterior; 6 specimens were used in each group. The correlations between screw fixation modalities, screw positions and axial pullout strength were analyzed. An appropriate screw trajectory and insertional depth were confirmed using axial and sagittal X-ray imaging prior to pullout testing. In both bicortical and unicortical fixation modalities, the screw pullout force was significantly higher in the posterior or middle position than in the anterior position (p

This paper studies the problem of developing an efficient signal sampling framework for distributed blind spectrum sensing, together with the corresponding local cognitive radio (CR) decision and fusion rules. A novel collaborative sampling and binary output (CSBO) generating scheme is proposed to overcome the disadvantage of traditional energy detectors for blind spectrum sensing, in which the signal-to-noise ratio (SNR) and level of noise power at the CRs are unknown and thus the decision threshold of local energy detectors cannot be specified. In designing the fusion rule in conjunction with the proposed CSBO scheme, both fixed-sample-size tests and sequential tests are considered. It is theoretically shown that the proposed CSBO scheme outperforms traditional blind cooperative energy detectors with uniform sampling schemes in terms of its ability to increase the amount of information acquired under a given number of samples. Simulation results confirm the theoretical analyses, and demonstrate that, compared with the fixed-sample-size test, the sequential test requires fewer observations on average to achieve comparable detection performance. The reduction in the expected sample size needed in the sequential CSBO test when compared to the fixed-sample-size CSBO can reach 50% when primary signal is present.

Three key factors are responsible for the biomechanical performance of pedicle screw fixation: screw mechanical characteristics, bone quality and insertion techniques. To the best of the authors’ knowledge, no study has directly compared the biomechanical performance among three trajectories, i.e., the traditional trajectory (TT), modified trajectory (MT) and cortical bone trajectory (CBT), in a porcine model. This study compared the pullout strength and insertion torque of three trajectory methods in single vertebrae, the pullout strength and fixation stiffness including flexion, extension, and lateral bending in a one-level instrumented functional spinal unit (FSU) that mimics the in vivo configuration were clarified. A total of 18 single vertebrae and 18 FSUs were randomly assigned into three screw insertion methods (n = 6 in each trajectory group). In the TT group, the screw converged from its entry point, passed completely inside the pedicle, was parallel to the superior endplate, was located in the superior third of the vertebral body and reached to at least the anterior third of the vertebral body. In the MT group, the convergent angle was similar to that of the TT method but directed caudally to the anterior inferior margin of the vertebral body. The results of insertion torque and pullout strength in single vertebrae were analyzed; in addition, the stiffness and pullout strength in the one-level FSU were also investigated. This study demonstrated that, in single vertebrae, the insertion torque was significantly higher in CBT groups than in TT and MT groups (p < 0.05). The maximal pullout strength was significantly higher in MT groups than in TT and CBT groups (p < 0.05). There was no significant difference in stiffness in the three motions among all groups. The maximal pullout strength in FSUs of MT and CBT groups were significantly higher than the TT groups (p < 0.05). We concluded that either MT or CBT provides better biomechanical performance than TT in single vertebrae or FSUs. The lack of significance of stiffness in FSUs among three methods suggested that MT or CBT could be a reasonable alternative to TT if the traditional trajectory was not feasible.

Background: Postoperative immunosuppression is associated with blood loss and surgical trauma during surgery and subsequently predisposes patients to increased morbidity. Spine endoscopic surgery has been accepted as an effective surgical technique with less surgical trauma and less blood loss for the complication of infectious spondylodiscitis. Therefore, the aim of this study was to investigate whether PEIDF could reduce the morbidity rates for patients with infectious spondylodiscitis. Methods: We launched a retrospective cohort study on the comparison of the perioperative prognosis between PEIDF and conventional open surgery for single-level lumbar infectious spondylodiscitis in patients with poor physical health (ASA ≥ 4) from 2014 to 2019. Results: Forty-four patients were included in this study. Fifteen of them underwent PEIDF, and the rest of the 29 patients were treated with open surgery. Less surgical blood loss (p < 0.001) and intraoperative transfusions (p < 0.001) with a better decline of CRP (p = 0.017) were statistically significant in patients receiving PEIDF. Patients undergoing conventional open surgery encountered more postoperative sepsis (p = 0.030), a higher qSOFA score (p = 0.044), and prolonged-time for CRP normalization (p = 0.001). Conclusions: PEIDF minimizes a poor postoperative outcome due to less surgical trauma, intraoperative blood loss, and the need for a blood transfusion.

Pedicle screw fixation is one of the most common procedures used in spinal fusion surgery. The screw loosening is a major concern, which may be caused by broken pedicles. In vitro pullout tests or insertion torque are the main approaches for assessing the stability of the screw; however, direct evidence was lacking for clinical human spines. Here, we aim to provide a model that can predict the pullout strengths of pedicle screws in various pedicle conditions from X-ray images. A weighted embedded bone volume (EBV) model is proposed for pullout strengths prediction by considering the bone heterogeneity and confinement of the screw. We showed that the pullout strength is proportional to the EBV for homogeneous bone and the weighted EBV for layered composite bone. The proposed weighted EBV model is validated with in vitro Sawbones® pullout experiments. The results show that the model has better accuracy than the simple EBV model, with a coefficient of determination of 0.94. The proposed weighted EBV model can help assess the stability of a pedicle screw in a broken pedicle by simply examining 2D X-ray images.

Study Design: Biomechanical study. Objective: Cross-links are a type of common clinical spinal instrumentation. However, the effects of the position and number of cross-links have never been investigated in long-segment spinal fixation, and the variables have not been optimized. We conducted an in vitro biomechanical study by using a porcine long-segment spinal model with 5 different crosslink configurations to determine the optimal construct for clinical practice. Methods: Five modalities with paired segmental screws from T15-L5 were tested in 20 porcine spines. The spines without cross-links composed the control group, Group A; those with a single cross-link from L2-3 composed Group B; those with 2 cross-links from L1-2 and L3-4 composed Group C; those with 2 cross-links from T15-L1 and L4-5 composed Group D; and those with 3 cross-links from T15-L1, L2-3 and L4-5 composed Group E. Spinal stiffnesses in flexion, extension, lateral bending, and axial rotation were compared among 5 different cross-link configurations in 5-level porcine spinal units. Results: Flexional, extensional and lateral bending stiffnesses did not significantly change with an increasing number of cross-links or positions in the construct. Axial stiffness was significantly increased with 2 cross-links compared to one ( P < 0.05) and with placement more distant from the center of the long spinal fixation construct ( P < 0.05). Conclusions: Two cross-links individually placed proximal and distal from the center of a construct is an optimal and efficient configuration to achieve biomechanical stability in non-rigid lumbar spines undergoing long-level fixation.

Objective Spinal cord compression secondary to metastatic epidural lung cancer generally has a worse prognosis when compared with other metastatic tumors. The purpose of this study was to determine the impact of open surgery on the survival time, ambulation status, and associated prognostic variables of these patients over the past 2 decades. Methods We searched the PubMed, MEDLINE, and CENTRAL databases to identify patients with spinal cord compression secondary to metastatic lung cancer. We assessed the role of the following factors on survival outcome and ambulation recovery: Karnofsky Performance Scale, number of extraspinal bone metastases, number of metastases in the vertebrae, major internal organs involvement, vertebral location of spinal metastases, and neurologic status. Results Our initial search yielded 367 articles, from which 11 studies met the eligibility criteria for a total of 395 patients. Significant correlations with the survival period and the recovery in ambulation were found in the prognostic score for the number of metastases in vertebrae (R = 0.74 and 0.88, respectively), and in the prognostic score for metastases to major internal organs (R = 0.82 and 0.81, respectively). A significant correlation with survival period was found in the numbers of extraspinal bone metastases (R = −0.82). The rates of major complications were comparable with those for open surgery for metastatic tumors of other origin. Conclusions Fewer vertebral metastases and less major internal organ involvement were associated with longer survival periods and greater ambulation recovery in patients undergoing open surgery for spinal cord compression secondary to metastatic lung cancer.

Multiple percutaneous vertebral cement augmentation may create sandwich vertebrae. Whether the sandwich vertebra is at higher risk of further fracture remains unknown.To compare the incidence of further fractures of sandwich vertebrae and adjacent vertebrae and to identify potential risk factors for sandwich vertebral fractures.Patients who underwent cement augmentation for osteoporotic vertebral compression fractures (OVCFs) in a single medical center between January 2012 and December 2015 were included. A sandwich vertebra was defined as an intact vertebra located between 2 previously cemented vertebrae. Demographic data and imaging findings were recorded. All patients were followed up for at least 24 mo postoperatively. During follow-up period, if the patient reported new-onset back pain with corresponding imaging findings, a diagnosis of sandwich vertebral fracture was made.Among the 1347 patients who underwent vertebroplasty/kyphoplasty for OVCFs, 127 patients with 128 fracture levels met the criteria for sandwich vertebrae (females/males 100/27, mean age 77.8 ± 7.7 yr old). The fracture location was most common in the thoraco-lumbar junction (T10-L2), 68.5% (87/127). The incidence of sandwich vertebral fracture was 21.3%, whereas the incidence of adjacent level fracture of those with no sandwich vertebra was 16.4% (196/1194), P = .1879.The incidence of sandwich vertebral fracture is not higher than that at the adjacent levels. The factor associated with further sandwich vertebral fracture was male gender. Once sandwich vertebral fracture occurred, patients may seek more surgical intervention than those with only adjacent fractures.

A screen image synthesis (SIS) system is superior than the conventional methods in terms of high-speed measurement and low screen-cross-talk noise when used as a whole-field light-distribution meter. However, reflection signals cannot be measured using the conventional SIS system when it is used as a scattering meter. Furthermore, the conventional SIS system cannot be used to measure a large sample when it is used as an intensity distribution meter. In this study, we devised a rail-based SIS system as long as an image reconstruction algorithm. This would allow whole-field scattering light and intensity distribution measurements for various sample sizes. For this purpose, a versatile instrument was assembled by combining a whole-field intensity distribution meter and a whole-field scattering meter. The results of the experiments confirmed that the measuring time was drastically improved when the proposed instrument was used as a whole-field intensity distribution meter and a whole-field scattering meter. The high normalized cross correlation values of both measurements demonstrated the accuracy and feasibility of the proposed algorithm.

The present study aimed to investigate the neural mechanism underlying semantic processing in Mandarin Chinese adult learners, focusing on the learners who were Indo-European language speakers with advanced levels of proficiency in Mandarin Chinese. We used functional magnetic resonance imaging technique and a semantic judgment task to test 24 Mandarin Chinese adult learners (L2 group) and 26 Mandarin Chinese adult native speakers (L1 group) as a control group. In the task, participants were asked to indicate whether two-character pairs were related in meaning. Compared to the L1 group, the L2 group had greater activation in the bilateral occipital regions, including the fusiform gyrus and middle occipital gyrus, as well as the right superior parietal lobule. On the other hand, less activation in the bilateral temporal regions was found in the L2 group relative to the L1 group. Correlation analysis further revealed that, within the L2 group, increased activation in the left middle temporal gyrus/superior temporal gyrus (M/STG, BA 21) was correlated with higher accuracy in the semantic judgment task as well as better scores in the two vocabulary tests, the Assessment of Chinese character list for grade 3 to grade 9 (A39) and the Peabody Picture Vocabulary Test-Revised. In addition, functional connectivity analysis showed that connectivity strength between the left fusiform gyrus and left ventral inferior frontal gyrus (IFG, BA 47) was modulated by the accuracy in the semantic judgment task in the L1 group. By contrast, this modulation effect was weaker in the L2 group. Taken together, our study suggests that Mandarin Chinese adult learners rely on greater recruitment of the bilateral occipital regions to process orthographic information to access the meaning of Chinese characters. Also, our correlation results provide convergent evidence that the left M/STG (BA 21) plays a crucial role in the storage of semantic knowledge for readers to access to conceptual information. Moreover, the connectivity results indicate that the left ventral pathway (left fusiform gyrus-left ventral IFG) is associated with orthographic-semantic processing in Mandarin Chinese. However, this semantic-related ventral pathway might require more time and language experience to be developed, especially for the late adult learners of Mandarin Chinese.

In this study, we propose a novel design of the triangular mesoscale Janus prisms for the generation of the long photonic hook. The numerical simulations based on the finite-difference time-domain method are used to examine the formation mechanism of the photonic hook. The electric intensity distributions near the micro-prisms are calculated for operating at different re-fractive indices and spaces of the two triangular micro-prisms. The asymmetric vortexes of in-tensity distributions result in the long photonic hook with large bending angle. The length and the bending angle of the photonic hook are efficiently modulated by changing the space be-tween the two triangular micro-prisms. Moreover, the narrow width of the photonic hook is achieved beyond the diffraction limit. The triangular Janus micro-prisms have high potential for practical applications in optical tweezers, nanoparticle sorting and manipulation and photonic circuits., Comment: 8 Figures

Introduction: In patients under immunosuppression or severe sepsis, it is sometimes manifested as coexisting septic arthritis and spondylitis. The aim of this study is to evaluate and investigate the risk factors of infectious spondylitis associated with septic arthritis. Methods: The study retrospectively reviewed the patients diagnosed with infectious spondylitis between January 2010 and September 2018 for risk factors of coexisting major joint septic arthritis. Results: A total of 10 patients with infectious spondylitis and coexisting septic arthritis comprised the study group. Fifty matched patients with solely infectious spondylitis were selected as the control group. Major risk factors include preoperative C-reactive protein (p = 0.001), hypoalbuminemia (p = 0.011), history of total joint replacement (p &lt, 0.001), duration of preoperative antibiotics treatment (p = 0.038) and psoas muscle abscess (p &lt, 0.001). Conclusion: Infectious spondylitis and septic arthritis are thought of as medical emergencies due to their high mortality and morbidity. Our study evaluated 5 risk factors as significant major findings: hypoalbuminemia (&lt, 3.4 g/dL), higher preoperative CRP (&gt, 130 mg/L), psoas muscle abscess, longer preoperative antibiotics treatment (&gt, 8 days) and history of total joint replacement. Clinicians should pay attention to the patients with those five factors to detect the coexisting infections as early as possible.

We propose a volume holographic optical element (VHOE) used as an objective turret in a lensless digital holographic microscope. It also served as a reference wave guide to reduce the volume of the system. For further optimization of resolution performance, it used a spherical wave in the object light of the VHOE, which served as the reference light of the microscope. Another sheared spherical wave was used to illuminate the sample. The optimized VHOE increased the spatial resolution of the record signal effectively. Furthermore, the change of spherical wave distance leads to the change of imaging magnification.

Background A considerable propotion of patients with cancer got thoracolumbar vertebral metastatic epidural spinal cord compression, which affected their quality of life. Traditional surgical management involves early decompression with concomitant spine stabilization with long instrumentation. However, complications are caused by massive blood loss and long operation time. This study aimed to compare the safety and efficacy of short posterior instrumentation with kyphoplasty and the traditional method for thoracolumbar metastatic epidural spinal cord compression. Methods Between January 2004 and December 2015, a retrospective study was conducted on 120 patients with metastatic epidural spinal cord compression from T6 to L5 and divided into 2 groups: short posterior instrumentation with the balloon kyphoplasty group (group I, n = 50) and the long posterior instrumentation group (group II, n = 70). The clinical and radiographic parameters of patients in the 2 groups were compared with a nonrandomized cohort method. Patients were followed up from 3 to 40 months after surgery according to survival time. Results In group I, the surgery had a mean blood loss of 650 mL and a survival time of 19.1 months. In group II, the surgery had a mean blood loss of 2100 mL and a survival time of 14.14 months. A significant difference in blood loss amount (P = 0.002) was observed. Complications, including deep wound infection, durotomy, and uncontrolled bleeding, were observed in both groups. No postoperative cement-induced neurologic deterioration, implant failure occurred. Conclusions Kyphoplasty with short posterior instrumentation is a novel technique that can be performed safely and effectively for the treatment of thoracolumbar metastatic epidural spinal cord compression. Rigid stability, reduced blood loss, and short fixation decrease surgical morbidity of spinal metastasis.

Allograft bone particles, hydroxyapatite/β-hydroxyapatite-tricalcium phosphate (HA/β-TCP), calcium sulfate (CS), and polymethylmethacrylate (PMMA) bone cement are biomaterials clinically used to fill defective pedicles for pedicle screw augmentation. Few studies have systematically investigated the effects of various biomaterials utilized for salvage screw stabilization. The aim of this study was to evaluate the biomechanical properties of screws augmented with these four different materials and the effect of different pilot hole sizes and bone densities on screw fixation strength. Commercially available synthetic bones with three different densities (7.5 pcf, 15pcf, 30 pcf) simulating different degrees of bone density were utilized as substitutes for human bone. Two different pilot hole sizes (3.2 mm and 7.0 mm in diameter) were prepared on test blocks to simulate primary and revision pedicle screw fixation, respectively. Following separate specimen preparation with these four different filling biomaterials, a screw pullout test was conducted using a material test machine, and the average maximal screw pullout strength was compared among groups. The average maximal pullout strength of the materials, presented in descending order, was as follows: bone cement, calcium sulfate, HA/β-TCP, allograft bone chips and the control. In samples in both the 3.2 mm pilot-hole and 7.0 mm pilot-hole groups, the average maximal pullout strength of these four materials increased with increasing bone density. The average maximal pullout strength of the bone cement augmented salvage screw (7.0 mm) was apparently elevated in the 7.5 pcf test block. Salvage pedicle screw augmentation with allograft bone chips, HA/β-TCP, calcium sulfate, and bone cement are all feasible methods and can offer better pullout strength than materials in the non-augmentation group. Bone cement provides the most significantly augmented effect in each pilot hole size and bone density setting and could be considered preferentially to achieve larger initial stability during revision surgery, especially for bones with osteoporotic quality.

Minimal invasive spinal fusion has become popular in the last decade. Oblique lumbar interbody fusion (OLIF) is a relatively new surgical technique and could avoid back muscle stripping and posterior complex destruction as in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Between December 2016 and September 2018, patients with single level degenerative spondylosis were selected to enroll in this retrospective study. A total of 21 patients that underwent OLIF and 41 patients that received MIS-TLIF were enrolled. OLIF showed significantly less blood loss and shorter surgery time compared to MIS-TLIF (p

Polymethylmethacrylate (PMMA) has been applied clinically and biomechanically repair loose pedicle screws. Controversies have arisen over data due to uncontrolled cement properties, various locations and sizes of fenestrated holes in repair screws, irregular holes and different bone densities of specimens. In this study, the pullout strength was compared for two techniques, the modified technique to use PMMA to augment a threaded hole and the traditional technique with retrograde injection of a PMMA filling, for standard loose screws in porcine vertebrae. Both techniques provided statistically significant results for sufficiently randomized specimens and experimental procedures. The difference in the pullout strength between conical and cylindrical screws for the aforementioned cement augmentation techniques was also investigated. Twenty-four single-level fresh-frozen lumbar vertebrae from L1 to L6 were harvested from four mature pigs. A total of 0.8 ml of PMMA was retrograde injected into screw holes with a 5.5 mm diameter, followed by insertion of a 5.0 mm diameter repair screw in the traditional group (n = 12). A stiff threaded PMMA hole was created with a 4.5 mm tapping screw before insertion of repair screws in the modified group (n = 12). Two screw geometries were randomly assigned as cylindrical (n = 6) and conical (n = 6) in each group. The correlations between filling techniques, screw geometries and axial pullout strength were analyzed. An appropriate screw trajectory and insertion depth were confirmed using X-ray imaging prior to pullout testing in both groups. For a given screw geometry (cylindrical or conical), the pullout force of the modified group was significantly higher than that of the traditional group. There was no significant difference in the pullout force between the screw geometries for a given filling technique. The cement augmentation technique is far more influential than the screw outer geometry. The modified PMMA technique created a greater anchor force than the traditional method and could be an alternative for revision of pedicle screw loosening.

Human poly(ADP)-ribose polymerase-1 (PARP1) is a global regulator of various cellular processes, from DNA repair to gene expression. The underlying mechanism of PARP1 action during transcription remains unclear. Herein, we have studied the role of human PARP1 during transcription through nucleosomes by RNA polymerase II (Pol II) in vitro. PARP1 strongly facilitates transcription through mononucleosomes by Pol II and displacement of core histones in the presence of NAD+ during transcription, and its NAD+-dependent catalytic activity is essential for this process. Kinetic analysis suggests that PARP1 facilitates formation of “open” complexes containing nucleosomal DNA partially uncoiled from the octamer and allowing Pol II progression along nucleosomal DNA. Anti-cancer drug and PARP1 catalytic inhibitor olaparib strongly represses PARP1-dependent transcription. The data suggest that the negative charge on protein(s) poly(ADP)-ribosylated by PARP1 interact with positively charged DNA-binding surfaces of histones transiently exposed during transcription, facilitating transcription through chromatin and transcription-dependent histone displacement/exchange.

With the coming of information age, the laboratory and the manufacture factory begins to import smart monitor system to enhance safety. The smart monitor system can save human costs. The information system can prevent unsafety event from happening. Smart Laboratory Administrator System was developed to cooperate with IoT (Internet of things) to prevent illegal invasion and achieve internal security. If unexpected events happen, it will work and switch on an alarm to prevent objects in the laboratory from being stolen. Hence, the Smart Laboratory Administrator System can save the human cost and enhance the security of laboratory.

Fish-farming is an entertainment for many people, but changing the water always takes a lot of time. The temperature of water will be changed during changing the water, and the quality of the water usually affects the fish life. This research was accompanied with smart sensor and fish tanks to achieve the smart fish tank. The smart fish tank owns Wi-Fi module which could collect the information of environment and control switch to maintain temperature, quality, inflow and outflow of water. IFTTT is used to send message in the smart fish tank. Besides, the light opening time was controlled to be suitable for nature light time that can bring more convenience for owner.

The modern conversational agent requires high-quality datasets, which are often the bottlenecks when building models. This paper introduces MatDC, an entirely human-produced dialogue dataset with full semantic annotations in Chinese. The dataset features linguistic variations given users’ intents and fully annotated semantic slots. MatDC dataset was completely human-edited, and the curation comprises two stages. At first, templates design stage, domain editors first construct schemas and compose ten dialogues between the agents and the users based on the back- end database. Secondly, in the dialogue rewrite stage, rewriters generate sentential variations for each template, under the constraints that the normalized slot values are kept unchanged. The underlying methodology of the MatDC is more open to extension and more adaptable to different domains. To demonstrate the applicability of the dataset, we build a dialogue agent with conventional pipeline architecture. We expect the MatDC dataset to provide additional training data and testing ground for dialogue agent studies.

Background Minimal invasive spinal fusion has become popular in the last decade. Oblique lumbar interbody fusion (OLIF) is a relatively new surgical technique and could avoid back muscle stripping and posterior complex destruction as in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Methods Between December 2016 and September 2018, patients with single level degenerative spondylosis were selected to enroll in this retrospective study. Results A total of 21 patients that underwent OLIF and 41 patients that received MIS-TLIF were enrolled. OLIF showed significantly less blood loss and shorter surgery time compared to MIS-TLIF (p

BackgroundWidely used in recent years, mesenchymal stem cells (MSCs) expressing enhanced green fluorescent protein (eGFP) can be tracked during migration to injury sites, while also supporting tri-lineage differentiation. However, the relationship between the expression of green fluorescence and the magnitude of osteogenic differentiation is not clearly defined. Despite increasing use of eGFP-MSCs derived from the transgenic pigs and non-viral eGFP plasmid transfected MSCs in recent years, it remains unclear which cells are suitable for tracking during osteogenic differentiation, and whether the transfected plasmid alters osteogenic potential.MethodsWe compared the expression of green fluorescence and the magnitude of osteogenic differentiation between eGFP MSCs from a transgenic pig (group 1) and non-virally transfected eGFP-MSCs using transIT®-2020 (group 2). Non-transfected MSCs were used as control group (group 3). We also use a scaffold to compare the osteogenic induction environments created by 2-D monolayer cultures and 3-D cultures, respectivelyResultsIn the monolayer culture, flow cytometry from day 7 to day 28 showed that the percentage of green fluorescent cells in groups 1 and 2 were 99.6% and 59.7% of total cell counts, respectively. Quantification showed that eGFP expression peaked on day 7, decreased after day 14, and plateaued to day 28 in group 1 and group 2. Significant aggregation of eGFP over bone-like nodules was appreciated in group 1. In 3-D culture, eGFP expression increased from day 7 to day 28 in both groups, and was higher in group 1 than in group 2 at each time point. Osteogenic profiles and immunohistochemistry showed more significant osteogenic activity in group 1 and group 3 than in group 2. ConclusionsThe expression of eGFP in the test groups did not significantly change after osteogenic induction. However, quantification data was different in monolayer and 3-D cultures due to spatial limitations, differing extracellular environments, and heterogeneous cell morphology and methods of division. Osteogenic profiles and immunohistochemistry data confirmed that osteogenic potential did not change in transgenic pig-derived MSCs. However osteogenic potential decreased in pig MSCs (pig MSCs) treated with the transfection reagent, likely from related toxicity.

In this paper, we study the problem of blind spectrum sensing by exploring signal sampling at each cognitive radio (CR) in a distributed cognitive radio network. Specifically, a new cooperative sampling scheme is proposed to deal with the challenge of unknown signal-to-noise ratio and level of noise power at each CR, which is a more realistic assumption in distributed spectrum sensing. We prove that the observations acquired by the proposed collaborative sampling are informative from an information theoretic perspective. Simulation results also demonstrate better receiver operating characteristics (ROC) of the proposed sampling scheme than the traditional uniform sampling scheme.

Purpose We investigated whether spinopelvic parameters are important prognostic factors for adjacent segment degeneration after long instrumented spinal fusion for degenerative spinal disease. Methods This uncontrolled, randomized, single arm retrospective study included patients who underwent long instrumented lumbar fusion (fusion levels≥ 4) in the past 5 years with follow-up for at least 2 years. The inclusion criteria included adult patients (≥40 years of age) with a diagnosis of spinal degeneration who underwent instrumented corrective surgery. The exclusion criteria included preexisting adjacent disc degeneration, combined anterior reconstructive surgery, and distal ASD. Clinical and operative characters were evaluated. Lumbar lordotic angle (LLA), sacral slope angle (SSA), pelvic tilt angle (PTA) and pelvic incidence angle (PIA) were compared preoperatively, postoperatively and at the final follow-up. Results From 2009 to 2014, 60 patients (30 ASD and 30 non-ASD patients) were enrolled. The average age was 66.82 ± 7.48 years for the study group and 67.97 ± 7.81 years for the control group. There was no statistically significant difference in clinical and operative characteristics. Among all spinopelvic parameters, only pre-, post-operative and final follow-up PIA in ASD group (53.9±10.4ﾟ, 54.6±14.0ﾟ, 54.3±14.1ﾟ) and non-ASD group (60.3±13.0ﾟ, 61.8±11.3ﾟ, 62.5±11.2ﾟ) showed statistically significant differences (p

Background: Cervical spine infections are uncommon but potentially dangerous, having the highest rate of neurological compromise and resulting disability. However, the factors related to surgical success is multiple yet unclear. Methods: We retrospectively reviewed the medical records of 27 patients (16 men and 11 women) with cervical spine infection who underwent surgical treatment at Chang Gung Memorial Hospital, Linkou branch, between 2001 and 2014. The neurological status, by Frankel classification, was recorded preoperatively and at discharge. Group X had neurologic improvement of at least 1 grade, group Y had unchanged neurologic status, and group Z showed deterioration. We recorded the patient demographic data, presenting symptoms and signs, interval from admission to surgery, surgical procedure, laboratory data, perioperative antibiotic course, pathogens identified, coexisting medical disease, concomitant nonspinal infection, and clinical outcomes. We intended to evaluate the different characteristics of patients who improved neurologically after treatment. Results: The mean age of our cohort was 56.6 years. Anterior cervical discectomy and fusion was the most commonly performed surgical procedure (74.1%). The Frankel neurological status improved in 70.4% (group X, n = 19) and unchanged in 29.6% (group Y, n = 8). No patients worsened. Motor weakness was most common (96.3%) neurological deficit, followed by sensory abnormalities (37.0%), and bowel/urine incontinence (33.3%). The main difference in presentation between group X and group Y was neck pain (100% vs. 75.0%; p = .02), not fever. Group X had a shorter preoperative antibiotic course (p = .004), interval from admission to operation (p = .02), and hospital stay (p = .01). Conclusion: Clinicians should be more suspicious in patients who present with neck pain and any neurological involvement even in those without fever while establishing early diagnosis. Earlier operative treatment in group X result in better neurologic recovery and shorter hospital stay due to disease improvement. Keywords: Spondylodiscitis, Epidural abscess, Osteomyelitis, Neurologic manifestation, Risk factors

OBJECTIVESpinopelvic parameters, such as the pelvic incidence (PI) angle, sacral slope angle, and pelvic tilt angle, are important anatomical indices for determining the sagittal curvature of the spine and the individual variability of the lumbar lordosis (LL) curve. The aim of this study was to investigate the influence of spinopelvic parameters and LL on adjacent-segment degeneration (ASD) after short lumbar and lumbosacral fusion for single-level degenerative spondylolisthesis.METHODSThe authors retrospectively reviewed the records of all short lumbar and lumbosacral fusion surgeries performed between August 2003 and July 2010 for single-level degenerative spondylolisthesis in their orthopedic department.RESULTSA total of 30 patients (21 women and 9 men, mean age 64 years) with ASD after lower lumbar or lumbosacral fusion surgery comprised the study group. Thirty matched patients (21 women and 9 men, mean age 63 years) without ASD comprised the control group, according to the following matching criteria: same diagnosis on admission, similar pathologic level (≤ 1 level difference), similar sex, and age. The average follow-up was 6.8 years (range 5–8 years). The spinopelvic parameters had no significant influence on ASD after short spinal fusion.CONCLUSIONSNeither the spinopelvic parameters nor a mismatch of PI and LL were significant factors responsible for ASD after short spinal fusion due to single-level degenerative spondylolisthesis.

Gene therapy for bone tissue engineering has been widely developed. Recently, non-viral DNA-based gene therapy has been reported to be a safer and more efficient method of delivering DNA into target cells. We used a non-viral gene transfection reagent to delivery bone morphogenetic protein-2 (BMP-2) gene into bone marrow stromal cells (BMSCs). Primary BMSCs were isolated from rat femurs and transfected with BMP-2 plasmids. The transfection rate was analyzed using flow cytometry. The concentration of BMP-2 protein was quantified using an enzyme-linked immunosorbent assay. Levels of osteopontin and osteocalcin were measured to evaluate osteogenic differentiation. In vivo, we designed a critical-size calvarial defect rat model to study new bone regeneration, using Matrigel as a scaffold to carry BMP-2-transfected bone marrow stromal cells into the defect site. New bone formation was assessed by micro-computed tomography, X-ray, immunohistochemical staining and histomophometry. The transfection rate after 72 h was 31.5%. The BMP-2 protein level as well as osteopontin and osteocalcin expressions were higher in the experimental group (transfected with BMP-2) than the control group (transfected with green fluorescent protein, GFP). The in vivo study suggested that bone healing occurred 12 weeks after scaffold implantation. In addition, BMP-2-transfected bone marrow stromal cells provided better osteogenic differentiation than primary bone marrow stromal cells. Our findings suggest that non-viral gene therapy may be useful in bone tissue engineering. Significance The study has clinical implications for the wider use of BMP-2-transfected BMSCs for cell-based transplantation therapy in bone regeneration.

Background Multiple percutaneous vertebral cement augmentation may create sandwich vertebrae. Whether the sandwich vertebra is at higher risk of further fracture remains unknown. Objective To compare the incidence of further fractures of sandwich vertebrae and adjacent vertebrae and to identify potential risk factors for sandwich vertebral fractures. Methods Patients who underwent cement augmentation for osteoporotic vertebral compression fractures (OVCFs) in a single medical center between January 2012 and December 2015 were included. A sandwich vertebra was defined as an intact vertebra located between 2 previously cemented vertebrae. Demographic data and imaging findings were recorded. All patients were followed up for at least 24 mo postoperatively. During follow-up period, if the patient reported new-onset back pain with corresponding imaging findings, a diagnosis of sandwich vertebral fracture was made. Results Among the 1347 patients who underwent vertebroplasty/kyphoplasty for OVCFs, 127 patients with 128 fracture levels met the criteria for sandwich vertebrae (females/males 100/27, mean age 77.8 ± 7.7 yr old). The fracture location was most common in the thoraco-lumbar junction (T10-L2), 68.5% (87/127). The incidence of sandwich vertebral fracture was 21.3%, whereas the incidence of adjacent level fracture of those with no sandwich vertebra was 16.4% (196/1194), P = .1879. Conclusion The incidence of sandwich vertebral fracture is not higher than that at the adjacent levels. The factor associated with further sandwich vertebral fracture was male gender. Once sandwich vertebral fracture occurred, patients may seek more surgical intervention than those with only adjacent fractures.

In Generative Lexicon Theory (glt) (Pustejovsky 1995), co-composition is one of the generative devices proposed to explain the cases of verbal polysemous behavior where more than one function application is allowed. The English baking verbs were used as examples to illustrate how their arguments co-specify the verb with qualia unification. Some studies (Blutner 2002; Carston 2002; Falkum 2007) stated that the information of pragmatics and world knowledge need to be considered as well. Therefore, this study would like to examine whether glt could be practiced in a real-world Natural Language Processing (nlp) application using collocations. We have conducted a fine-grained logical polysemy disambiguation task, taking the open-sourced Leiden Weibo Corpus as resource and computing with Support Vector Machine (svm) classifier. Within the classifier, we have taken collocated verbs under glt as main features. In addition, measure words and syntactic patterns are extracted as additional features for comparison. Our study investigates the logical polysemy of the Chinese verb kao ‘bake’. We find that glt could help in identifying logically polysemous cases; additional features would help the classifier achieve a higher performance.

Mutations in CHD7 are diagnostic for human CHARGE syndrome. RNAs expressed from the HERVH repeats modulate CHD7 function providing one mechanism for regulation of differentiation of pluripotent cells., Chd7 encodes an ATP-dependent chromatin remodeler which has been shown to target specific genomic loci and alter local transcription potentially by remodeling chromatin structure. De novo mutations in CHD7 are the major cause of CHARGE syndrome which features multiple developmental defects. We examined whether nuclear RNAs might contribute to its targeting and function and identified a preferential interaction between CHD7 and lncRNAs derived from HERVH loci in pluripotent stem cells. Knockdown of HERVH family lncRNAs using LNAs or knockout of an individual copy of HERVH by CRISPR-Cas9 both resulted in increased binding of CHD7 and increased levels of H3K27ac at a subset of enhancers. Depletion of HERVH family RNAs led to the activation of multiple genes. CHD7 bound HERVH RNA with high affinity but low specificity and this interaction decreased the ability of CHD7 to bind and remodel nucleosomes. We present a model in which HERVH lncRNAs act as a decoy to modulate the dynamics of CHD7 binding to enhancers in pluripotent cells and the activation of numerous genes that might impact the differentiation process.

Poly(methyl methacrylate) (PMMA) has been widely used in orthopedic applications, but bone ingrowth and toxic monomer release are drawback of this material. Particle reinforcement with osteoconductive substitute, such as calcium sulfate (CaSO4), is one of the solutions used to modify PMMA bone cement. The current study investigated the mechanical, chemical and biological properties of CaSO4-augmented bone cement. Mechanical strength was measured by a material testing machine. The concentration of methyl methacrylate (MMA) monomer from the various formulations of PMMA mixed with CaSO4was measured by ultra-performance liquid chromatography (UPLC). CCK-8 assay and ALP assay were performed to evaluate cytotoxicity of released MMA monomer and cell differentiation. The attachment of cells to CaSO4-augmented bone cement discs was observed by confocal and scanning electron microscopy, and surface topography was also evaluated by atomic force microscopy. The results revealed that increased CaSO4weight ratios led to compromised mechanical strength and increased MMA monomer release. Cell density and cell differentiation on CaSO4-augmented bone cement discs were decreased at CaSO4weight ratios above 10%. In addition, the presence of micropores on the surface and surface roughness were both increased for PMMA composite discs containing higher levels of CaSO4. These results demonstrated that fewer MC3T3-E1 cells on the surface of CaSO4-PMMA composites was correlated to increased MMA monomer release, micropore number and surface roughness. In summary, the augmentation of a higher proportion of CaSO4(>10 wt. %) to PMMA did not promote the biological properties of traditional PMMA bone cement.

This paper investigates the most frequent lexical bundle (LB) ka li kong (to-you-say) (KLK), in an 18.5-hour Taiwanese Southern Min conversation corpus. The analysis focuses on the discourse-pragmatic functions of KLK, the role it plays in the speaker’s management of information in talk-in-interaction, and the collocations that are employed. The results show that the speaker utilizes KLK to imply epistemic authority regarding the veracity of the predication. Meanwhile, it expresses the speaker’s stance or functions as a discourse organizer to initiate a narrative that is newsworthy. Prosodically, it is always processed as a holistic chunk with great phonological reduction. Along with the low transitivity of the verb kong demonstrated by the type of object it takes, we argue that KLK is developing into a discourse marker. Collocation of KLK with the marker toh further triggers the grammaticalization of the four-word bundle toh ka li kong (TKLK) to encode an extreme stance.

Editor’s note: This article points out that the fundamental problem of platform verification is incompleteness of the test plan and proposes an unsupervised learning approach to augment the test plan. –Magdy Abadir, Helic Inc.

Background To investigate the role of vertebral augmentation in kyphosis reduction, vertebral fracture union, and correction loss after surgical management of thoracolumbar burst fracture. Design Retrospective chart and radiographic review. Setting Level 1 trauma center. Methods The analysis included patients treated between April 2007 and June 2015, who received pedicle-screw-rod distraction and reduction within two days following acute traumatic thoracolumbar burst fracture with a load sharing score >6. Medical records were retrospectively reviewed for data regarding operative details, imaging and laboratory findings, neurological function, and functional outcomes. Intervention Not applicable. Main outcome measures Sagittal index, pain score, loss of correction, and implant failure rate. Results Nineteen patients were enrolled in this study (mean age, 37.2 ± 13 years; age range, 17–62 years; female/male ratio: 10/9). Of the five patients who received only reduction (no augmentation), one underwent revision surgery because of implant failure and pedicle screw backing out. Compared to patients who received only reduction, those who received both reduction and augmentation showed better sagittal alignment after the operation, with better sagittal index immediately postoperatively and during the follow-up (p Conclusions Transpedicular vertebral augmentation with calcium sulfate/phosphate-based bone cement may reinforce thoracolumbar burst fracture stability, partially restore vertebral body height, and reduce pedicle screw bending and movement, thereby preventing early implant failure and late loss of correction, especially in patients with excellent fracture reduction. Level of evidence: Therapeutic level III, retrospective chart review

The morphological status of affixes in Chinese has long been a matter of debate. How one might apply the conventional criteria of free/bound and content/function features to distinguish word-forming affixes from bound roots in Chinese is still far from clear. Issues involving polysemy and diachronic dynamics further blur the boundaries. In this paper, we propose three quantitative features in a computational model of affixoid behavior in Mandarin Chinese. The results show that, except for in a very few cases, there are no clear criteria that can be used to identify an affix’s status in an isolating language like Chinese. A diachronic check using contextualized embeddings with the WordNet Sense Inventory also demonstrates the possible role of the polysemy of lexical roots across diachronic settings.

BackgroundThe risk factors, incidence, and clinical management of pulmonary cement embolism and neurological deficit during percutaneous vertebroplasty (PVP) were evaluated.MethodsThree thousand one hundred and seventy-five patients with symptomatic osteoporotic vertebral compression fractures (OVCFs) treated with PVP were retrospectively reviewed in a single institution. Clinical parameters such as age, gender, number of fractures, and time from fracture to vertebroplasty were recorded at the time of surgery. Image and surgical parameters including the amount of cement, the vertebral level, uni- or bipedicle surgical approach, and leakage pattern were recorded.ResultsType-C leakage, including paraspinal (25%), intradiscal (26%), and posterior (0.7%) leakage, was more common than type-B (11.4%) and type-S leaks (4.9%). Cement leakage into the spinal canal (type-C posterior) occurred in 26 patients (0.7%), and four patients needed surgical decompression. Three in nine patients with leakage into thoracic spine needed decompressive surgery, but only one of 17 patients into lumbar spine needed surgery (p< 0.01). Age, gender, number of fractures, and time from fracture to vertebroplasty were not risk factors of pulmonary cement embolism or neurological deficit. The risk factor of pulmonary cement embolism was higher volume of PMMA injected (p< 0.001) and risk factor of neurological deficit was type-C posterior cement leakage into thoracic spine. The incidence of pulmonary cement embolism was significantly high in the volume of PMMA injected (PMMA injection 7.0 cc: 0.9%;p< 0.01) which needed postoperative oxygen support.ConclusionsCement leakage is relatively common but mostly of no clinical significance. Percutaneous vertebroplasty in thoracic spine and high amount of PMMA injected should be treated with caution in clinical practice.

We design an array of transverse slots cut out from the broad wall of a groove-gap waveguide, with periodic spacing between slots of a guided wavelength at 28 GHz that is centered about an important millimeter-wave band. External horns are brought upon to address the problem of grating lobes. The simulations have been carried out for operation in the designed frequency band from 27.676 to 28.652 GHz while preserving the conditions for port matching. This antenna solution lends itself to many applications within this millimeter-wave band.