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Study Design: Retrospective study. Objective: Lumbar magnetic resonance imaging (MRI) findings are believed to be associated with low back pain (LBP). This study sought to develop a new predictive classification system for low back pain. Method: Normal subjects with repeated lumbar MRI scans were retrospectively enrolled. A new classification system, based on the radiological features on MRI, was developed using an unsupervised clustering method. Results: One hundred and fifty-nine subjects were included. Three distinguishable clusters were identified with unsupervised clustering that were significantly correlated with LBP ( P = .017). The incidence of LBP was highest in cluster 3 (57.14%), nearly twice the incidence in cluster 1 (30.11%). There were obvious differences in the sagittal parameters among the 3 clusters. Cluster 3 had the smallest intervertebral height. Based on follow-up findings, 27% of subjects changed clusters. More subjects changed from cluster 1 to clusters 2 or 3 (14.5%) than changed from cluster 2 or cluster 3 to cluster 1 (5%). Participation in sport was more frequent in subjects who changed from cluster 3 to cluster 1. Conclusion: Using an unsupervised clustering method, we developed a new classification system comprising 3 clusters, which were significantly correlated with LBP. The prediction of LBP is independent of age and better than that based on individual sagittal parameters derived from MRI. A change in cluster during follow-up may partially predict lumbar degeneration. This study provides a new system for the prediction of LBP that should be useful for its diagnosis and treatment.

Diabetes mellitus contributes to intervertebral disc degeneration. Nucleus pulposus cell senescence plays an important role in intervertebral disc degeneration. However, the effects of hyperglycemia on human nucleus pulposus cells and the underlying process remains poorly understood. In the current study, we evaluated the effects of high glucose levels on human nucleus pulposus cell senescence in vitro and the effects of hyperglycemia on rat nucleus pulposus aging in vivo. Human nucleus pulposus cells were cultured in high-glucose medium (200 mM glucose) for 48 h. Senescence-associated β-galactosidase staining, western blot analysis, and enzyme-linked immunosorbent assays were performed to evaluate human nucleus pulposus cell senescence. Flow cytometry and enzyme-linked immunosorbent assays were used to evaluate reactive oxygen species and advanced glycation end-product levels. Transcriptome sequencing followed by bioinformatics analysis was used to understand the abnormal biological processes of nucleus pulposus cells cultured in high-glucose medium. Diabetes mellitus rat models were established and histopathological and immunohistochemical analysis was conducted to examine nucleus pulposus tissue senescence in vivo. Exposure to a high glucose concentration promoted human nucleus pulposus cell senescence and increased the senescence-related secretion phenotype in human nucleus pulposus cells in vitro and in rat nucleus pulposus tissue in vivo. Bioinformatics analysis showed that hub genes were involved in nucleus pulposus cell cycle activities and cell senescence. The results suggest that appropriate blood glucose control may be key to preventing intervertebral disc degeneration in diabetic patients.

China is rich in oyster resources and has a long history of oyster aquaculture. Various forms of oyster aquaculture coexist in the coastal regions of China, which are dominated by raft aquaculture and long-line aquaculture. The objective of this study is to assess the environmental sustainability of the oyster aquaculture systems located in Jiantiao Bay, Zhejiang province, China. Emergy synthesis is used in the study to quantify the contributions of the natural and economic inputs to the oyster aquaculture systems, in order to better understand the sustainability. The results show that the raft oyster aquaculture system was high in emergy inputs and yield per unit area, whereas the long-line oyster aquaculture system was low in emergy inputs and yield per unit area. However, the transformities of the oysters from the raft oyster aquaculture system and the long-line aquaculture were similar, reflecting that both systems had a similar efficiency in using natural and economic resources. The oyster aquaculture systems had a different impact on the environment as inferred from the emergy indicators. The higher emergy yield ratio and low emergy loading ratio in the long-line oyster aquaculture system suggest that the system could gain more net benefit, and had a lower impact on the surrounding environment, than raft oyster aquaculture system, and can been considered to be more sustainable. Nevertheless, oyster aquaculture was a labor-intensive process and relied highly on purchased resources, such as labor and construction materials. If the construction materials could be used for a longer time, the oyster aquaculture systems might be more sustainable and environmentally friendly.

Objective To compare the effect of different fixation methods on spinal stability after total en bloc spondylectomy(TES) of lumbar spine.Method The finite element models were established based on the CT scan of a healthy volunteer. After the validity of the models was confirmed, the models with different posterior fixation methods of the lumbar spine were established with and without the artificial vertebral body, respectively. The motions of flexion, extension, lateral bending and rotation under supine and standing conditions were simulated. The angular displacement of T11-L3 and stress of internal fixations were compared and analyzed.Results The finite element models of spinal reconstruction after TES were obtained. When the anterior support existed, the movement of the spine after TES was not affected by the gravity of the upper body. The movements in the opposite direction on the same plane were similar. All three methods provided enough stability to the spine. The improved short-segment fixation shared stress of the artificial vertebral body with no obvious negative effect. The long-segment fixation had stronger fixation effect with the huge loss of the range of motion of lumbar spine. When the anterior support failed, obvious rotation showed in lateral bending in all models. The short-segment fixation and the long-segment fixation failed to maintain the spinal stability with fixations breakage or functional loss. The improved short-segment fixations showed strong ability in maintaining the spinal stability. The vertebral body screws can prevent the failure of anterior fixation by sharing great stress of the whole internal fixation system. The improved short-segment had huge advantages over the others.Conclusion After TES, the improved short-segment fixation can provide more stability to the spine. The vertebral body screws can prevent the failure of the internal fixation by reducing the stress of the anterior support. This fixation method should be promoted in clinical practice while the effect requires more observation.

A retrospective clinical study.This study sought to retrospectively compare the mid-term to long-term outcomes between unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) augmented transforaminal lumbar interbody fusion (TLIF) in lumbar degenerative diseases.Recently, UPS fixation has been applied in TLIF, for its satisfactory clinical outcome, less implants and less invasiveness. However, only short-term outcome has been reported, the mid-term to long-term outcome has not been well characterized.From June 2007 to February 2011, 215 of 348 consecutive patients suffering from lumbar degenerative diseases were operated in our hospital and accomplished a minimum of 4-year follow-up. These patients were divided into 2 groups according to the operative techniques: UPS group (n=109), and bilateral pedicle screw group (n=106). Operative time, blood loss, length of hospital stay, hospital bill, fusion status, and complications were recorded and analyzed statistically. Visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores were used to assess the preoperative and postoperative pain and functional outcome.The mean follow-up duration was 52.2 months. A significant decrease occurred in operative time, blood loss, and hospital bill in unilateral group, compared with bilateral group (P0.05). The average postoperative visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores improved significantly in each group than the preoperative counterparts (P0.05); however, there were no significant difference between groups at any follow-up time point (P0.05). No statistically difference was detected regarding fusion rate and complication rate between the 2 groups (P0.05), except the cage migration rate (P0.05).UPS fixation could achieve satisfactory clinical outcome similar to bilateral fixation in TLIF at a mid-term to long-term follow-up. To avoid cage migration, bullet-shaped cages should not be used in the unilateral group.

Objective In this retrospective study, a modified measurement method was used to analyze cage migration during follow-up after unilateral instrumented transforaminal lumbar interbody fusion (TLIF) and identify associated factors. Methods We retrospectively evaluated 75 patients who had been treated with unilateral instrumented TLIF. Cage migration was quantitatively defined as anterior–posterior or lateral displacement of the cage. Results Five patients had significant cage migration (6.7%), but none developed severe neural symptoms during follow-up or underwent reoperation. The cages tended to migrate posteriorly or toward the side of surgery. The initial cage position and patient age were strongly associated with migration. Migration was less frequent when the cages were initially placed closer to the side of surgery. Patients of advanced age were more likely to develop anterior–posterior migration than were young patients. Conclusion Cage migration is related to the initial position of the cage. Particular attention is required when performing unilateral instrumented TLIF in patients of advanced age because they are most likely to develop cage migration. Quantification of cage migration is an effective method of exploring the associated factors.

It is technically demanding and requires rich experience to insert the translaminar facet screw(TFS) via the paramedian mini-incision approach. It seems that it is easy to place the TFS using computer-assisted design and rapid prototyping(RP) techniques. However, the accuracy and safety of these techniques is still unknown. The aim of this study is to assess the accuracy and safety of translaminar facet screw placement in multilevel unilateral transforaminal lumbar interbody fusion using a rapid prototyping drill guide template system. A patient-matched rapid prototyping translaminar facet screw guide was examined in fourteen cadaveric lumbar spine specimens. A three-dimensional (3D) preoperative screw trajectory was constructed using spinal computed tomography scans, from which individualized guides were developed for the placement of translaminar facet screws. Following bone tunnel establishment, the 3D positioning of the entry point and trajectory of the screws was compared to the preoperative plan as found in the Mimics software.Among 60 trajectories eligible for assessment, no cases of clinically significant laminar perforation were found. The mean deviation between the planned and the actual starting points on spinous process was 1.22 mm. The mean tail and submergence angle deviation was found to be 0.68°and 1.46°, respectively. Among all the deviations, none were found to have any statistical significance. These results indicate that translaminar facet screw placement using the guide system is both accurate and safe.

OBJECT This study sought to make a biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders. METHODS Eight fresh-frozen human cadaver lumbar spines (4 from L-1 to L-5, 4 from L-1 to S-1) were tested by applying pure moments of ± 8 Nm. Each specimen was first tested intact, and then the left facetectomies of L3–4 and L4–5 were performed to establish an unstable condition without removal of discs. Three instrumentation systems were then tested randomly: unilateral pedicle screw (UPS), UPS with contralateral translaminar facet screw (UPSFS), and bilateral pedicle screw (BPS). The range of motion (ROM) and the neutral zone (NZ) of L3–5 were measured. RESULTS All fixation types could reduce the ROM of L3–5 significantly in flexion, extension, and lateral bending, compared with the intact state. In axial torsion, only BPS reduced the ROM significantly, compared with the intact state. The UPSFS technique provided intermediate stability, which was superior to the UPS in flexion-extension and lateral bending, and inferior to the BPS in lateral bending. Compared with the intact state, the NZs decreased significantly for UPS, UPSFS, and BPS in flexion-extension, while not significantly in lateral bending and axial torsion. CONCLUSIONS In this study, among the 3 fixation techniques, BPS offered the highest stability, UPSFS provided intermediate stability, and UPS was the least stable for 2-level lumbar spinal disorders. UPSFS appeared to be able to offer a less invasive choice than BPS in well-selected patients with 2-level lumbar spinal disorders.

The aim of this study was to evaluate the risk factors between ipsilateral and contralateral reherniation and to compare the effectiveness of miniopen transforaminal lumbar interbody fusion (TLIF) with unilateral fixation for each group. From November 2007 to December 2014, clinical and radiographic data of each group (ipsilateral or contralateral reherniation) were collected and compared. Functional assessment (Visual Analog Scale (VAS) score and Japanese Orthopaedic Association (JOA)) and radiographic evaluation (fusion status, disc height, lumbar lordosis (LL), and functional spine unit (FSU) angle) were applied to compare surgical effect for each group preoperatively and at final followup. MacNab questionnaire was applied to further evaluate the satisfactory rate after the discectomy and fusion. No difference except pain-free interval was found between ipsilateral and contralateral groups. There was a significant difference in operative time between two groups. No differences were found in clinical and radiographic data for assessment of surgical effect between two groups. The satisfactory rate was decreasing in both groups with time passing after discectomy. Difference in pain-free interval may be a distinction for ipsilateral and contralateral reherniation. Miniopen TLIF with unilateral pedicle screw fixation can be a recommendable way for single level reherniation regardless of ipsilateral or contralateral reherniation.

Background: Transforaminal lumbar interbody fusion (TLIF) has been used in lumbar degenerative diseases. Some researchers have applied unilateral fixation in TLIF to reduce operational trauma without compromising the clinical outcome, but it is always suspected biomechanically unstable. The supplementary contralateral translaminar facet screw (cTLFS) seemed to be able to overcome the inherent drawbacks of unilateral pedicle screw (uPS) fixation theoretically. This study evaluates the safety, feasibility and efficacy of TLIF using uPS with cTLFS fixation in the treatment of lumbar degenerative diseases (LDD). Materials and Methods: 50 patients (29 male) underwent the aforementioned surgical technique for their LDD between December 2009 and April 2012. The results were evaluated based on visual analogue scale (VAS) of the leg and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI) were recorded. The radiographic examinations in form of X-ray, computed tomography (CT) or magnetic resonance imaging was done preoperatively and 1 week, 3 months, 6 months, 12 months and 24 months postoperatively. The student t-test was used for comparison between the preoperative values and postoperative counterparts. P < 0.05 was considered to be statistically significant. Results: Among 50 patients, 22 received one level fusion and 28 two level′s, with corresponding operation time and estimated blood loss being approximately 90 min, 150 ml and 120 min, 200 ml, respectively. No severe complications happened perioperatively. The mean VAS (back, leg) scores dropped from (7.6, 7.5) preoperatively to (2.1, 0.6) at 12 months′ followup, ODI from 49.1 preoperatively to 5.6 and JOA score raised from 10.6 preoperatively to 28.5, all P < 0.001, suggesting of good clinical outcome. From the three-dimensional reconstructed CT, 62 out of 70 segments displayed solid fusion with fusion rate of 88.6% at 12 months postoperatively. Conclusions: TLIF using uPS fixation plus cTLFS fixation is a safe, feasible and effective technique in the treatment of one or two level lumbar degenerative diseases short termly.

A self-control study was designed to compare the process of creeping substitution between allograft bone and local bone grafting in lumbar interbody fusion. From December 2011 to July 2012, 81 patients (mean age: 56.4) were included in this study and randomly allocated to two groups. Leopard cages were using in unilateral instrumentation transforaminal lumbar interbody fusion. In group 1, the cages were filled with the local bone on the side of the instrumentation and allograft bone on the other side. In group 2, they were totally filled with the local bone chips. Then, the special CT-reconstructions were made at 6- and 12-month follow-up. On the sagittal section, the sections of CT-reconstructions were perpendicular to the lateral axis of the cage from the side of the cage to the other side. Similarly, they were parallel to the lateral axis of the cage on the coronal section and intervertebral space on the cross section. The mean area size of bone mass on both sides of the cage was calculated, respectively, using image analysis software (Osirix, version 3.3.2) on each section in two groups. In group 1, at 6- and 12-month follow-up, significant differences were observed in the mean area size of bone mass between allograft bone and local bone grafting on the coronal, cross, and sagittal section. In group 2, the mean area size of local bone on both sides of the cage had no significant differences at 6- and 12-month follow-up on each section. The results of our study showed a superiority of local bone grafting over allograft bone.

Degenerative disc disease is a multifaceted progressive irreversible condition and an inevitable part of aging, which has been found to be a contributing factor for low back pain and might cause radiculopathy, myelopathy, spinal stenosis, degenerative spondylolisthesis, and herniations. Its etiology is complex and multifactorial. Although genetics influence more dominant, the occupational and mechanical influences still persist as a major risk factor. This review emphasizes up-to-date knowledge regarding etiology of disc degeneration with special consideration on occupational, lifestyle factors, and genetic polymorphisms.

Backgrounds A variety of improved surgical methods were adopted in the transforaminal lumbar interbody fusion. A mechanical stability provides an ideal environment for the formation of a fusion mass and is the basis of their good outcomes. The object of this study is to evaluate the initial similarities and differences of four commonly-used posterior surgical procedures biomechanically. Methods Biomechanical testing was performed at L3–4 motion segment in 6 fresh-frozen human cadaveric lumbar spines (L2–L5), including the following sequentially tested configurations: 1) intact motion segment; 2) bilateral pedicle screw fixation; 3) unilateral pedicle screw fixation; 4) unilateral pedicle screw plus contralateral translaminar facet joint screw fixation according to the Magerl technique; and 5) bilateral pedicle screw fixation with bilateral facetectomies. The range of motion, neutral zone and stiffness of each method and intact segment were collected and compared. Findings All of four methods reduce the range of motion significantly in flexion and extension and lateral bending but not in axial torsion compared with the native segment. There is no significant difference among four procedures about the range of motion in all loading modes. All of methods increase the stiffness of segmental motion compared with intact segment in all loading modes, but only bilateral pedicle screw fixation showed significant increases in stiffness in flexion and extension( p = 0.02) and lateral bending( p = 0.023). The stiffness offered by instrumented constructs in different methods showed no significant difference in all loading modes. Interpretation The stiffness offered by four different posterior fixations in single segmental transforaminal lumbar interbody fusion is not significantly different.

In the present paper an experimental procedure and a finite element model were used to explore the possibilities of determining the creep-damage parameters of duralumin alloy 2A12 incorporated with modified Kachanov–Rabotnov (K–R) creep-damage constitutive equations. To study the phenomenon of creep damage of 2A12 a set of uniaxial tensile creep tests were carried out at 210 °C at different loads—1800, 2000 and 2200 N. From the experiment results and by using the optimum software ISIGHT, creep-damage parameters of duralumin alloy 2A12 based on the modified K–R creep-damage constitutive equations can be obtained by fitting the creep curves. Then, a finite element model was established by implementing a user subroutine in order to predict the creep damage. The optimum results were in agreement with the experimental results as well as the finite element method (FEM) results. The FEM results also showed that the creep damage at about the central part developed faster. An important conclusion obtained from the comparison was that the modified K–R creep-damage constitutive equations could be used to predict the creep damage and the residual strength as well as the optimum method could be used to treat the experimental results and calculate the creep-damage parameters of some metal materials.

This study sought to retrospectively compare three different posterior fixation techniques in transforaminal lumbar interbody fusion for two-level lumbar degenerative diseases.This was a retrospective single-center study including 84 patients who underwent TLIF instrumented with unilateral pedicle screws (UPS), unilateral pedicle screws plus contra-lateral translaminar facet screws (UPSFS), or bilateral pedicle screws (BPS) between June 2008 and May 2012. These patients were divided into three groups: UPS (n=22), UPSFS (n=28) and BPS (n=34) group. Operative time, blood loss, length of hospital stay, hospital bill, fusion status and complications were recorded and analyzed statistically. Visual analog scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopaedic Association Scores (JOA) were used to assess the preoperative and postoperative pain and functional outcome. Sagittal alignment was evaluated by the segment lordosis (SL) and whole lumbar spine lordosis (LL).The mean follow up duration was 46.2 (ranging from 36 to 60) months. A significant decrease occurred in operative time, blood loss and hospital bill in UPS and UPSFS group, compared with BPS group (p0.05). The average postoperative VAS, ODI and JOA scores improved significantly in each group than the preoperative counterparts (p0.05), however, there were no significant difference between groups at any follow-up time point (p0.05). No statistically difference was detected regarding fusion rate and complication rate between groups (p0.05), except the screw/rod failure rate (p0.05). Radiographic analysis showed that the LLs in all these groups got improved (p0.05) and the SLs maintained (p0.05).UPS or UPSFS instrumented TLIF could achieve satisfactory mid-term clinical outcome comparable to BPS's, with less surgical time, less blood loss, and lower cost; UPS should be prudently performed for two-level cases in case of lower fusion rate, and cannulated screws should be replaced by stronger solid screws in UPSFS to reduce facet screw breakage.

A retrospective study was designed to evaluate clinical outcomes and sagittal alignment following single-level unilateral instrumented transforaminal lumbar interbody fusion (TLIF). From November 2008 to December 2010, a total of 139 patients, who suffered from single-level lumbar degenerative disease, were included in this study. Forty-seven males and seventy-two females with a mean age of 57.3 years were enrolled. The average follow-up period was 51.7 months with a range of 41–66 months. The follow-up rate was 85.6 %. Thirty-one patients had diagnosis of discogenic low back pain, ten had recurrent disk herniation, thirty-four had spinal stenosis, and fourty-four had spondylolisthesis. Clinical outcomes were evaluated using the Oswestry disability index (ODI), visual analog scale (VAS) and Japanese Orthopedic Association. Operating time, blood loss, length of stay, and complications were also evaluated. The sagittal alignment and fusion status were assessed by X-ray and three-dimensional computed tomography. The average operating time was 92.1 ± 27.5 min, the average blood loss was 135.1 ± 113.5 ml, and the average length of stay was 12.0 ± 2.9 days. The overall complication rate was 13.4 %, and the fusion rate was 82.4 %. The postoperative clinical outcomes and sagittal alignment were significantly different from the preoperative values. The final lumbar lordosis angle and segment lordosis angle were associated with back pain VAS and ODI scores, respectively. Unilateral instrumented TLIF is a safe and effective treatment option for single-level lumbar degenerative disease, and is less invasive, yields good outcomes and has a low complication rate. In addition, the procedure has the potential to partly restore sagittal alignment.

This paper is to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) using unilateral pedicle screws along with contralateral translaminar facet joint screw (UPS+TFS) fixation in comparison with the method using bilateral pedicle screws fixation (BPS) in degenerative lumbar diseases. Forty patients with single-level lumbar diseases were divided into two groups randomly. One group was treated by TLIF with BPS fixation while the other group was treated by the new technique with UPS+TFS fixation. The preoperative and postoperative ODI, JOA, VAPS scores, mean operation time, mean operation blood loss, fusion rate and complications were collected for comparison under two surgical methods. In terms of complications, only two cases of superficial infection in the BPS group and one case of urinary tract infection in the other group was found. The mean operation time and blood loss was significantly less in UPS+TFS group than in BPS group. The preoperation and postoperative ODI, JOA and VAPS at the intervals of 6 weeks, 3, 6 months and 1 year between the BPS and UPS+TFS group showed no significant disparities. Only one patient in UPS+TFS group was not fused with pseudoarthrosis formation. The clinical efficacy and safety of TLIF with UPS+TFS fixation were comparable to BPS fixation; however, the soft tissue injury and the corresponding operation cost were reduced with unilateral pedicle screw plus translaminar facet screw fixation.

This study compared the biomechanics of 3 fixation techniques: bilateral pedicle screw (BPS) fixation, unilateral pedicle screw (UPS) fixation, and UPS supplemented with translaminar facet screw (UPS+TLFS) fixation. The study was conducted in an L3–L5 finite element model. Three different finite element models were created by adopting different fixation techniques after removal of the left L3–L4 and L4–L5 facet joints. A 500-N compressive preload combined with 8-NM moment were applied in 3 finite element models with 3 fixation techniques during different movements. Angular displacement and stress distribution were recorded. As described in this article, the UPS model had the most variation in angular displacement, the BPS model was intermediate, and the UPS+TLFS model had the least mobility. Most of the stress accumulated on the body and tail of the pedicle screws and the connecting rods in the UPS and BPS models, but stress accumulated on the rods and the part of the facet joint pierced by the TLFS in the UPS+TLFS model. The middle part of the pedicle screw endured little stress compared with the upper and lower parts. The maximum stress on the fixation devices was highest in the UPS model. The maximum stress in the UPS+TLFS model was the lowest among the 3 models. Biomechanically, UPS+TLFS fixation is superior to either UPS fixation or BPS fixation in improving stability and reducing stress. Bilateral pedicle screw fixation is intermediate, and UPS fixation is inferior.

In current TLIF practice, the choice of the cage size is empirical and primarily depends on the case volume and experience of the surgeon. We used a self-made modified distractor handle in TLIF procedure with the goal of standardizing the intervertebral space tension and determining the proper cage size.

Neuroserpin (NSP) is a neuroprotective factor in the situation of ischemia of a brain, such as stroke. However, it has never been reported in the spinal cord, which is part of the central nervous system (CNS).The expression of NSP was detected using Western blotting and neuron apoptosis detected by TUNEL staining following spinal cord ischemia caused by sustained compression in rats.The results showed that NSP was upregulated in the injury area of spinal cord, accompanied with the activation of micorglia and tissue plasminogen activator (tPA), which suggested that NSP also plays a neuroprotective role in spinal cord compression since neuronal apoptosis appears when NSP returns to normal levels or even lower.NSP upregulates in early periods of sustained spinal cord compression.

ATP-binding cassette transporter A1 (ABCA1) is a membrane-associated protein which has attracted considerable attention as a candidate gene for Alzheimer’s disease (AD) based on its function as a key factor in lipid metabolism by mediating cellular cholesterol efflux, the rate-limiting step in the production of nascent high-density lipoprotein (HDL) particles. The relationship between ABCA1 common variations (R219 K rs2230806, I883 M rs4149313 and R1587 K rs2230808) and AD has been reported in various ethnic groups; however, these studies have yielded contradictory results. To investigate this inconsistency, we performed a meta-analysis of 13 studies involving a total of 12,248 subjects to evaluate the effect of ABCA1 on genetic susceptibility for AD. Overall, the summary OR of AD was 1.01 (95 % CI: 0.93–1.10; P = 0.77), 1.10 (95 % CI: 0.96–1.26; P = 0.16), and 1.08 (95 % CI: 0.96–1.23; P = 0.21) for R219 K, I883 M and R1587 K polymorphism, respectively. No significant results were observed in dominant and recessive when compared with wild genotype for these polymorphisms. In the stratified analyses by ethnicity and sample size, no evidence of any gene-disease association was obtained. In conclusion, the present meta-analysis does not support the notion that common SNPs on ABCA1 is a major genetic risk factor for AD.

[Abstract] Through statistic analysis of the 387 events of the failure of aircraft fuel or hydraulic system from 1986 to 2004 for the some aircraft, it is obtained that the failure of pump is susceptible, and the result of the failure of pump is analyzed. Divided the type of pump failure, the influence of pump speed was major form. A complete fuel system model is established in Flowmaster2 software, and steady state and transient state for the complete fuel system are analyzed. The results show it is a feasible for aircraft fuel system analysis. This validated model is used to simulate the influence of fuel pump failure on the stability of an aircraft fuel system. The result of the failure of pump is simulated, and the influence of main fuel pump on the fuel feeding stability of whole system is analyzed at transient states analysis, and the influence on the fuel pump obtained is obvious. No.2 and No.9 pump were investigated in this paper. It was obtained that the change of No.9 pump speed had no effect on the whole system but No.2 through simulating failure pump by the way of changing the pump speed. Aircraft’s flying control and war aims were affected directly even the life of pilot if No.2 fuel pump was broken up.