Nanoscale Bandgap Tuning across an Inhomogeneous Ferroelectric Interface

We report nanoscale bandgap engineering via a local strain across the inhomogeneous ferroelectric interface, which is controlled by the visible-light-excited probe voltage. Switchable photovolatic effects and the spectral response of the photocurrent were explore to illustrate the reversible bandgap variation (~0.3eV). This local-strain-engineered bandgap has been further revealed by in situ probe-voltage-assisted valence electron energy-loss spectroscopy (EELS). Phase-field simulations and first-principle calculations were also employed for illustration of the large local strain and the bandgap variation in ferroelectric perovskite oxides. This reversible bandgap tuning in complex oxides demonstrates a framework for the understanding of the opticallyrelated behaviors (photovoltaic, photoemission, and photocatalyst effects) affected by order parameters such as charge, orbital, and lattice parameters

Association of Short Tandem Repeat Polymorphism in the Promoter of Prostate Cancer Antigen 3 Gene with the Risk of Prostate Cancer

BACKGROUND: PCA3 (prostate cancer antigen 3) gene is one of the most prostate cancer-specific genes at present. Consequently, the prostate-specific expression and the sharp up-regulation of PCA3 mRNA in prostate cancer suggest a unique transcriptional regulation, which possibly can be attributed to promoter polymorphism. In our study, we evaluated whether there is polymorphism in PCA3 promoter region and also assess the association of the polymorphism with prostate cancer. METHODOLOGY/PRINCIPAL FINDINGS: We designed a specific primer set to screen the promoter of PCA3 gene by polymerase chain reaction (PCR)-based cloning and sequencing with the DNA extracted from peripheral blood samples of prostate cancer (PCa) cases (n = 186) and healthy control cases (n = 135). Genotype-specific risks were estimated as odds ratios (ORs) with associated 95% confidence intervals (CIs) by chi-square test. Possible deviation of the genotype frequencies from controls and PCa cases expected under Hardy-Weinberg equilibrium was assessed by the chi-square test. Short tandem repeat polymorphism of TAAA was found in the promoter region of PCA3 gene, five polymorphisms and eight genotypes were identified. The eight genotypes were divided into three groups: ≤10TAAA, 11TAAA, ≥12TAAA. The group 11TAAA and ≥12TAAA were associated with higher relative risk for prostate cancer than group ≤10TAAA (OR = 1.76, 95%CI = 1.07-2.89[for group 11TAAA]; OR = 5.28, 95%CI = 1.76-15.89[for group ≥12TAAA]). CONCLUSIONS/SIGNIFICANCE: The presence of the (TAAA)n short tandem repeat polymorphisms in the PCA3 promoter region may be a risk factor for prostate cancer in the Chinese population

Biomechanical evaluation of different sizes of 3D printed cage in lumbar interbody fusion-a finite element analysis

Abstract Objective To study the biomechanical characteristics of various tissue structures of different sizes of 3D printed Cage in lumbar interbody fusion. Methods A finite element model of normal spine was reconstructed and verified. Pedicle screws and Cage of different sizes were implanted in the L4/5 segment to simulate lumbar interbody fusion. The range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment were calculated and analyzed. Results The range of motion and intervertebral disc pressure of the adjacent segment of each postoperative model were larger than those of the intact model, but there was not much difference between them. The stress of cage-endplate interface was also larger than that of the intact model. However, the difference is that the stress of the endplate and the screw-rod system has a tendency to decrease with the increase of the axial area of cage. Conclusions Cage with larger axial area in lumbar interbody fusion can reduce the stress of internal fixation system and endplate, but will not increase the range of motion and intervertebral disc pressure of adjacent segment. It has a certain effect in preventing the cage subsidence, internal fixation system failure and screw rod fracture

Finite element biomechanical analysis of 3D printed intervertebral fusion cage in osteoporotic population

Abstract Objective To study the biomechanical characteristics of each tissue structure when using different 3D printing Cage in osteoporotic patients undergoing interbody fusion. Methods A finite element model of the lumbar spine was reconstructed and validated with regarding a range of motion and intervertebral disc pressure from previous in vitro studies. Cage and pedicle screws were implanted and part of the lamina, spinous process, and facet joints were removed in the L4/5 segment of the validated mode to simulate interbody fusion. A 280 N follower load and 7.5 N·m moment were applied to different postoperative models and intact osteoporotic model to simulate lumbar motion. The biomechanical characteristics of different models were evaluated by calculating and analyzing the range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment. Results After rigid fixation, the range of motion of the fixed segment of model A-C decreased significantly, which was much smaller than that of the osteoporotic model. And with the increase of the axial area of the interbody fusion cages, the fixed segment of model A-C tended to be more stable. The range of motion and intradiscal pressure of the spinal models with different interbody fusion cages were higher than those of the complete osteoporosis model, but there was no significant difference between the postoperative models. On the other hand, the L5 upper endplate stress and screw-rod system stress of model A-C show a decreasing trend in different directions of motion. The stress of the endplate is the highest during flexion, which can reach 40.5 MPa (model A). The difference in endplate stress between models A-C was the largest during lateral bending. The endplate stress of models A and B was 150.5% and 140.9% of that of model C, respectively. The stress of the screw-rod system was the highest during lateral bending (model A, 102.0 MPa), which was 108.4%, 102.4%, 110.4%, 114.2% of model B and 158.5%, 110.1%, 115.8%, 125.4% of model C in flexion, extension, lateral bending, and rotation, respectively. Conclusions For people with osteoporosis, no matter what type of cage is used, good immediate stability can be achieved after surgery. Larger cage sizes provide better fixation without significantly increasing ROM and IDP in adjacent segments, which may contribute to the development of ASD. In addition, larger cage sizes can disperse endplate stress and reduce stress concentration, which is of positive significance in preventing cage subsidence after operation. The cage and screw rod system establish a stress conduction pathway on the spine, and a larger cage greatly enhances the stress-bearing capacity of the front column, which can better distribute the stress of the posterior spine structure and the stress borne by the posterior screw rod system, reduce the stress concentration phenomenon of the nail rod system, and avoid exceeding the yield strength of the material, resulting in the risk of future instrument failure

Nanoscale Bandgap Tuning across an Inhomogeneous Ferroelectric Interface

We report nanoscale bandgap engineering via a local strain across the inhomogeneous ferroelectric interface, which is controlled by the visible-light-excited probe voltage. Switchable photovoltaic effects and the spectral response of the photocurrent were explored to illustrate the reversible bandgap variation (∼0.3 eV). This local-strain-engineered bandgap has been further revealed by <i>in situ</i> probe-voltage-assisted valence electron energy-loss spectroscopy (EELS). Phase-field simulations and first-principle calculations were also employed for illustration of the large local strain and the bandgap variation in ferroelectric perovskite oxides. This reversible bandgap tuning in complex oxides demonstrates a framework for the understanding of the optically related behaviors (photovoltaic, photoemission, and photocatalyst effects) affected by order parameters such as charge, orbital, and lattice parameters

Clinical characteristics.

a<p>Independent-Samples T Test between cases and controls, t = 1.20, P = 0.23.</p

Association between <i>PCA3</i> promoter STR polymorphisms and prostate carcinoma risk.

a<p>10, 11, 12 and 13 correspond to the total number of <i>TAAA</i> repeat in one allele.</p>b<p>10<i>TAAA</i> group includes the 9<i>TAAA</i> group.</p>c<p>4, 5, 6, 7 and 8 correspond to the number of <i>TAAA</i> repeat.</p

Association between <i>PCA3</i> promoter STR polymorphism and Gleason score in prostate carcinoma.

e<p>Spearman's rank correlation coefficient.</p

Repressentative PCR -based cloning and sequencing of STR polymorphism in the promoter region of <i>PCA3</i> gene.

<p><b>A</b>. (<i>TAAA</i>)₄ alleles; <b>B</b>. (<i>TAAA</i>)₅ alleles; <b>C</b>. (<i>TAAA</i>)₆ alleles; <b>D</b>. (<i>TAAA</i>)₇ alleles; <b>E</b>. (<i>TAAA</i>)₈ alleles.</p