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To solve the problem that how users choose access points in cell-free massive multiple-input multiple-output (CF-mMIMO) network, a prioritized access strategy for poorer users based on channel coefficient ranking was proposed.First, users were evaluated and ranked for their channel quality and stability after channel sensing, and suitable access points were selected in sequence according to the order of the channel state information.Second, considering issues such as users' energy consumption and data security, a federal learning framework was used to enhance user's data privacy and security.Meanwhile, an alternating optimization variables algorithm based on energy consumption optimization was proposed to optimize the multi-dimensional variables, for the purpose of minimizing the total energy consumption of the system.Simulation results show that compared with the traditional user-centric in massive MIMO, the proposed access strategy can improve the average uplink reachable rate of users by 20%, and the uplink rate of users with poor channels can be double improved; in terms of energy consumption optimization, the total energy consumption can be reduced by much more than 50% after optimization.

The hybrid Cartesian grid/gridless method is developed to simulate viscous flows. The flow field is basically discretized by Cartesian grids, and local gridless treatment is embedded in the region adjacent to the body. In order to simulate the thin boundary layer of the viscous flows interested in this paper, the cloud of anisotropic points is implemented in the local gridless region. A cloud overlap-free procedure is proposed which enables the hybrid method to treat complex flows involving close-coupled bodies. The unstructured Cartesian grid needed for the hybrid method is generated based on the quadtree data structure, which can help to control the quality of the clouds at the interface between the grid region and the gridless region. The resulting hybrid method is applied to solve two-dimensional compressible NS equations. The viscous flows past a NACA0012 airfoil and a RAE2822 airfoil are first simulated, and the numerical results obtained present a good agreement with available experimental data. The paper ends with a numerical example of the viscous flow past a two-element airfoil, which demonstrates the ability of the present method for treating more complex flows over multi-bodies. [ABSTRACT FROM AUTHOR]

The paper introduced characteristics of WiFi wireless communication system and its application at underground gas drilling site of Shihao Coal Mine. The actual application showed that WiFi wireless communication system realizes video monitoring and voice communication function at underground gas drilling site, so as to ground control center can make adjustment in time according to the underground scene.

Objective: To measure the correlative parameters of vertebral pedicles from L₁ to S₁ by CT scan in the patients with thoracolumbar kyphosis secondary to ankylosing spondylitis(AS) and disc degenerative disease(DDD), and analyze their anatomical difference in order to provide the selection and placement of pedicle screw during operation., Methods: The clinical data of 30 male AS patients (AS group) with the mean age of(35.7±9.5) years (ranged, 23 to 51) and 30 male DDD patients (DDD group) with the mean age of(52.4±8.9) years(ranged, 39 to 64) underwent surgery in our institution from March 2012 to November 2014 were analyzed. The CT scans of lumbar and sacrum were performed before surgery. The parameters of vertebral pedicle from L₁ to S₁ were measured and compared, including pedicle width (PW), pedicle screw path length (PL), pedicle height (PH), pedicle transverse angle (EA), and pedicle inclined angle (FA). Paired sample t-test was used to detect the divergence in the above-mentioned data between left and right sides. In addition, results between two groups were compared using independent sample t-test., Results: The study showed that a gradual increase in the average pedicle width both AS group and DDD group from L₁ to S₁. The average PW of AS group was bigger than DDD group in L₅ and S₁( P <0.05), it was(16.47±2.66) mm and (21.76±2.97)mm vs. (14.51±2.11)mm and (18.87±2.14) mm respectively;the average PL of DDD group was smaller than AS group from L₁ to S₁( P <0.05); the both maximum of PL were in L₃ segment; the average EA of AS group was smaller than DDD group from L₁ to S₁; the average FA of AS group was significantly smaller than DDD group from L₃ to S₁, ( P <0.05), was(-2.88±10.24)°, (-7.88±10.22)°, (-7.70±10.40)°, (-5.15±10.25)° vs. (4.05±2.21)°, (7.79±4.38)°, (7.07±3.21)°, (12.62±3.21)°, respectively., Conclusions: Increasing the strength of internal fixation is feasible to insert the larger and bigger pedicle screws in low lumbar and S₁ among AS patients, while the EA should be decreased properly and the direction on the sagittal plane should be adjusted., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.

Objective: To investigate the clinical outcome and fusion rate in patients with idiopathic thoracolumbar/lumbar scoliosis treated with anterior correction and interbody fusion with calcium phosphate cement., Methods: From October 2006 to March 2008, 24 cases undergoing anterior correction and interbody fusion with calcium phosphate cement were enrolled. All of them were female, with an age ranged from 12 to 25 years. The mean Cobb angle of main curve was 46° ± 5° (range, 40° - 56°) before surgery. During operation, the most proximal and distal disc spaces were filled with rib autograft, while the remaining levels were filled with calcium phosphate cement. The interbody fusion rate, coronal correction and sagittal profile reconstruction were evaluated respectively by using χ² test and t test., Results: Interbody fusion was performed in 103 levels, including 48 levels with rib autograft and 55 levels with calcium phosphate cement. The mean follow-up period was 23.8 months (range, 12 - 33 months) in this series. At the follow-up of 6 months, fusion rate was found as 54.2% in the levels filled with rib autograft, while 50.9% in those filled with calcium phosphate cement. Solid fusion of the whole instrumented area was achieved in all cases with a minimum one-year follow-up. No instrumentation-related complications occurred. The correction rate of main curve was on an average of 76% ± 11% after surgery. A significant difference was found between preoperative and immediate postoperative value in terms of the main curve magnitude (46° ± 5° vs. 14° ± 5°, t = -26.95, P < 0.05). The correction loss of the main curve was -5.1° - 10.4° at the final follow-up. The coronal balance and lower instrumented vertebra tilting were significantly improved after operation. The thoracolumbar kyphosis was significantly reduced postoperatively (t = 3.11, P < 0.05)., Conclusion: Satisfactory bone fusion and correction maintenance can be achieved in idiopathic thoracolumbar/lumbar scoliosis treated by anterior instrumentation combined with interbody fusion using calcium phosphate cement.

Objective: To investigate whether the titrate-resistant acid phosphatase 5 (ACP5) gene polymorphisms were associated with the occurrence or curve severity of adolescent idiopathic scoliosis (AIS)., Methods: There were 372 AIS patients from January 2006 to December 2008 and 239 normal controls from March 2005 to August 2006 were recruited. The Cobb angles were ≥ 10° in all AIS patients. Using the haplotype data of Han population from the Hapmap Project, two tag SNPs (rs2229531, rs2071484) were defined for ACP5 gene. PCR-restriction fragment length polymorphism was used for the genotyping., Results: No polymorphism in rs2229531 was found in this study. The genotype and allele frequency distribution in rs2071484 were similar between AIS patients and normal controls (χ(2) = 3.336 and 1.438, P > 0.05). The mean maximum Cobb angles of different genotypes of rs2071484 in ACP5 gene were 38° ± 19° in AA, 34° ± 14° in AG and 38° ± 21° in GG, which were similar with each other among AIS patients who reached skeletal maturity or received surgery treatment (P = 0.157)., Conclusion: The ACP5 gene is neither associated with the occurrence nor the curve severity of AIS.

Objectives: To compare the sagittal profiles between thoracic idiopathic scoliosis (IS) patients with different curve progression and to determine the risk factors associated with curve progression., Methods: A total of 83 thoracic IS patients from September 2009 to May 2010 were included in this study and were divided into 3 groups according to different curve progression. All the patients did not receive any previous treatments. There were 26 skeletally mature patients whose Risser sign were 5 degree with Cobb angle < 40° in non-curve progression group (NCP group), 29 mature patients whose Risser sign were 5 degree with Cobb angle ≥ 40° in moderate curve progression group (MCP group) and 28 immature patients whose Risser sign ≤ 3 degree with Cobb angle ≥ 40° in severe curve progression group (SCP group). Five sagittal parameters, including thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI) and pelvic tilt (PT) were measured on the lateral X-ray films. Analysis of variance was used to compare these parameters among the 3 groups., Results: The average thoracic Cobb angle was significantly smaller in NCP group when compared with MCP group (P < 0.01) or SCP group (P < 0.01), but not significantly different between the 2 latter groups (P = 0.619). The average TK was 19° ± 7° in NCP group, 13° ± 6° in MCP group and 8° ± 5° in SCP group. The average TK was significantly smaller in SCP group when compared with MCP group (P = 0.011) or NCP group (P < 0.01), while the average TK was significantly smaller in MCP group when compared with NCP group (P < 0.01). None of the other 4 parameters showed any significant difference between the 3 groups (P > 0.05)., Conclusions: Thoracic hypokyphosis is strongly associated with curve progression in thoracic IS patients. Pelvic sagittal profile may not be involved in the underlying mechanism of curve progression in thoracic IS patients.

Objective: To investigate the pulmonary dysfunction patterns in patients of scoliosis associated with neurofibromatosis type I (NF1) and to identify factors affecting the pulmonary function in patients with scoliosis associated with NF1., Methods: Preoperative pulmonary function tests (PFTs) were evaluated in 100 patients with scoliosis [NF1 group, 36 cases; idiopathic scoliosis (IS) group, 64 cases] from January 2003 to June 2009. According to location of apical vertebra and dystrophic change in patients with NF1, the parameters of pulmonary function [vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal mid-expiratory flow (MMEF), maximal voluntary ventilation (MVV)] were compared between NF1 group and IS group, and between the subgroups of NF1. The correlation between pulmonary function parameters and radiographic parameters of scoliosis was analyzed., Results: The VC, FVC, FEV1, MMEF, MVV in NF1 group and IS group were of no significant difference (P > 0.05). In NF1 patients, the pulmonary dysfunction was more severe in thoracic subgroup than non-thoracic subgroup (P < 0.05), while there was no difference between dystrophic scoliosis and non-dystrophic scoliosis (P > 0.05). The location of apical vertebra and the severity of scoliosis correlated significantly with the pulmonary dysfunction in NF1 group., Conclusions: The pattern of pulmonary dysfunction in scoliosis associated with NF1 is similar with IS. Pulmonary dysfunction is more severe in thoracic scoliosis. The location of apical vertebra and the severity of scoliosis are the risk factors influencing the pulmonary dysfunction.

Objective: To investigate the association between the tissue inhibitor of metalloproteinase-2 (TIMP-2) gene polymorphisms with the predisposition and disease severity of thoracic adolescent idiopathic scoliosis (AIS)., Methods: Three hundred and fifty-four female thoracic AIS patients treated from January 2007 to March 2009 and 210 healthy female who underwent health examination during March 2005 to June 2006 as normal controls were recruited in this study. One SNP-418G/C (rs8179090) in the promoter region were selected for TIMP-2 gene. PCR- RFLP was used for genotyping., Results: No significant differences of genotype and allele frequency distribution were found between AIS patients and normal controls (P > 0.05). In AIS patients, the frequency of C allele of the patients with the body mass index (BMI) < 17 kg/m(2) was significantly higher than those with the BMI > or = 17 kg/m(2) (P < 0.05), and the frequency of C allele of cases with the major Cobb angle > or = 40 degrees was significantly higher than that with Cobb angle < 40 degrees (P < 0.05). Among the patients who reached skeletal maturity without any interference of natural history, significantly higher average maximum Cobb angle was found in patients with GC and CC genotype compare with those with GG genotype., Conclusions: The SNP-418G/C (rs8179090) in the promoter region of TIMP-2 gene may be associated with abnormal growth pattern and curve progression of thoracic AIS. TIMP-2 gene is a disease-modifier gene of thoracic AIS.

Objective: To study whether antisense oligonucleotides and ultrasonic microbubble intensifier transfection combined with ultrasound irradiation is an effective and directional way in reversing multidrug resistance (MDR) in tumors., Methods: Mdr1, mrp, and lrp genes antisense oligonucleotides on the ultrasound microbubble intensifier were transfected for the human HepG2/ADM cell lines and then the cells were radiated with low intensity ultrasound. The effects of the reversion of carcinoma cells' MDR and the reduction of their malignancy and growth capability in vitro and in vivo were assessed using RT-PCR, Western blot and MTT., Results: The treatment restrained the multiplication of the human HepG2/AMD cell lines. The levels of their mRNA and protein of cells' mdr1 and mrp genes dropped significantly. Growth of the subcutaneous transplanted tumors in the nude mice decreased., Conclusions: Transfection of MDR genes antisense oligonucleotides on the ultrasonic microbubble intensifier combined with low intensity ultrasound radiation may serve as a new treatment method for hepatocellular carcinoma.