Ni Xinye

A Novel Strategy for Preparation of Si-HA Coatings on C/C Composites by Chemical Liquid Vaporization Deposition/Hydrothermal Treatments.

A novel strategy for the preparation of Si-doped hydroxyapatite (Si-HA) coatings on H2O2-treated carbon/carbon composites (C/C) was developed. HA coating was prepared on C/C through chemical liquid vaporization deposition (CLVD)/hydrothermal treatment. HA coating was immersed in an H2SiO3 solution at an autoclave at 413 K for transformation into Si-HA coating. The effects of H2SiO3 mass contents on the phase, morphology, and composition of the Si-HA coatings were studied through SEM, EDS,XRD, and FTIR. Their bonding performance to C/C was measured through a scratch test. Under the optimal content condition, the in vitro skull osteoblast response behaviors of the Si-HA coating were evaluated. Results showed that SiO32− could enter into the HA lattice and occupy the PO43− sites. Doped SiO32− significantly improved the bonding performance of the HA coating to C/C in comparison with the untreated HA. The adhesive strength of the coatings initially increased and then decreased with increasing H2SiO3 content. Meanwhile, the cohesive strength of the Si-HA coatings was almost nearly identical. The Si-HA coating achieved at a content of 90% H2SiO3 exhibited the best bonding performance, and its osteoblast compatibility in vitro was superior to that of the untreated HA coating on C/C through CLVD/hydrothermal treatment.

Individual humeral head replacement by C/C composite implants coated with hydroxyapatite via rotation plasma spraying

Abstract The humeral heads of rabbits were replaced with individualized C/C composite implants coated with hydroxyapatite (HA) via rotation plasma spraying. The effect of the implants was evaluated after 5 and 150 days by using histology, scanning electron microscopy, X-ray diffraction, and so on. Results showed that the coating interface of C/C composites facilitated phosphorite deposition and osseous tissue growth. Furthermore, the humeral bone and remaining bone tissues were morphologically similar and possessed enhanced bonding strength. These results indicated that individualized C/C composite implants with HA coatings enabled the humeral head to adapt to dynamic requirements and accelerate healing after bone transplantation.

A novel hydrogel-polydimethylsiloxane elastomer for wound dressing application

ABSTRACT Human skin is a perfect natural protective barrier in body defensive system and chronic, non-healing skin wounds like diabetic foot ulcers always lead to formidable consequence, high healthcare costs and even amputation of the patient. For many years, there is an urgent need for better wound dressing that promotes wound healing of refractory wounds. Here we report a novel hybrid hydrogel-polydimethylsiloxane (PDMS) elastomer (HPE), which is nontoxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts and has great anti-infection property. HPE could eliminate >94% of S.aureus and >99% of E.coli in the bacterial tests, revealing great potential of protecting the wounds from infection. HPE also exhibited a high water absorbing capacity from the environment, which is an important property for maintaining the wet environment around the wounds. In addition, HPE was self-sticky that could adhere to the wound surface without additional adhesive. These unique properties make HPE a promising candidate for wound dressing application.

Application of Metal Implant 16-Bit Imaging New Technique in Radiotherapy

Objective: This study aimed to evaluate the computed tomography number and the variation of dose distribution based on 12-bit, 16-bit, and revised 16-bit images while the metal bars were inserted. Methods: The phantoms containing stainless steel, titanium alloy, and aluminum bar were scanned with computed tomography. These images were reconstructed with 12-bit and 16-bit imaging technologies. The “cupping artifacts” computed tomography value of the metal object revised by Matlab software was called the revised 16-bit image. The computed tomography values of these metal materials were analyzed. Two radiotherapy treatment plans were designed using the treatment plan system: (1) gantry was of 0° irradiation field and (2) gantry was of 90° and 270° for 2 opposed irradiation fields. The dose profile and dose–volume histogram of a structure of interest were analyzed in various images. The analysis was based on the radiotherapy plan differences between 3 different imaging techniques (12-bit imaging, 16-bit imaging, and revised 16-bit imaging technologies). Results: For low-density metal object (computed tomography value <3071 Hounsfield unit, HU), the radiotherapy plan results were consistent based on 3 different imaging techniques. For high-density metal object (computed tomography value >3071 HU), the difference in radiotherapy plan results was obvious. The dose of 12-bit was 15.9% higher than revised 16-bit on average for the downstream of titanium rod. For stainless steel, this number reached up to 42.7%. Conclusion: A 16-bit imaging technology of metal implants can distinguish the computed tomography value of different metal materials. Furthermore, the revised 16-bit imaging technology can improve the dose computational accuracy of radiotherapy plan with high-density metal implants.

Spectral Imaging Technology-Based Evaluation of Radiation Treatment Planning to Remove Contrast Agent Artifacts:

Objective: This study employs dual-source computed tomography single-spectrum imaging to evaluate the effects of contrast agent artifact removal and the computational accuracy of radiotherapy treatment planning improvement. Method: The phantom, including the contrast agent, was used in all experiments. The amounts of iodine in the contrast agent were 30, 15, 7.5, and 0.75 g/100 mL. Two images with different energy values were scanned and captured using dual-source computed tomography (80 and 140 kV). To obtain a fused image, 2 groups of images were processed using single-energy spectrum imaging technology. The Pinnacle planning system was used to measure the computed tomography values of the contrast agent and the surrounding phantom tissue. The difference between radiotherapy treatment planning based on 80 kV, 140 kV, and energy spectrum image was analyzed. Results: For the image with high iodine concentration, the quality of the energy spectrum-fused image was the highest, followed by that of the 140-kV image. That of the 80-kV image was the worst. The difference in the radiotherapy treatment results among the 3 models was significant. When the concentration of iodine was 30 g/100 mL and the distance from the contrast agent at the dose measurement point was 1 cm, the deviation values (P) were 5.95% and 2.20% when image treatment planning was based on 80 and 140 kV, respectively. When the concentration of iodine was 15 g/100 mL, deviation values (P) were −2.64% and −1.69%. Conclusion: Dual-source computed tomography single-energy spectral imaging technology can remove contrast agent artifacts to improve the calculated dose accuracy in radiotherapy treatment planning.

Naturally-derived microparticles for hemostatic applications

ABSTRACT The research area of hemostatic biomaterials is an emerging field attracted lots of interests recently due to the soaring number of traumas. One of the key unmet needs in this area is non-toxic, non-irritating, cost-effective, hemostatic materials which can shorten blood clotting time effectively. Here we used naturally derived starch to prepare two types of new hemostatic microparticles, swellable and microporous starch particles. The hemostatic particles were characterized by optical and scanning electron microscopy and evaluated for their swelling and hemostatic properties. The results of in vitro blood test demonstrated a strong relationship between swelling power and blood clotting index (BCI). Also, the swellable microparticles had dominant ability of water/blood absorption over the microporous particles, accelerating the aggregation of red blood cells, thrombin, platelets and fibrin and other active components on the particle surface and thus achieving better hemostatic effect.

Sensitivity of 3D Dose Verification to Multileaf Collimator Misalignments in Stereotactic Body Radiation Therapy of Spinal Tumor

Purpose: This study aimed to detect the sensitivity of Delt 4 on ordinary field multileaf collimator misalignments, system misalignments, random misalignments, and misalignments caused by gravity of the multileaf collimator in stereotactic body radiation therapy. Methods: (1) Two field sizes, including 2.00 cm (X) × 6.00 cm (Y) and 7.00 cm (X) × 6.00 cm (Y), were set. The leaves of X1 and X2 in the multileaf collimator were simultaneously opened. (2) Three cases of stereotactic body radiation therapy of spinal tumor were used. The dose of the planning target volume was 1800 cGy with 3 fractions. The 4 types to be simulated included (1) the leaves of X1 and X2 in the multileaf collimator were simultaneously opened, (2) only X1 of the multileaf collimator and the unilateral leaf were opened, (3) the leaves of X1 and X2 in the multileaf collimator were randomly opened, and (4) gravity effect was simulated. The leaves of X1 and X2 in the multileaf collimator shifted to the same direction. The difference between the corresponding 3-dimensional dose distribution measured by Delt 4 and the dose distribution in the original plan made in the treatment planning system was analyzed with γ index criteria of 3.0 mm/3.0%, 2.5 mm/2.5%, 2.0 mm/2.0%, 2.5 mm/1.5%, and 1.0 mm/1.0%. Results: (1) In the field size of 2.00 cm (X) × 6.00 cm (Y), the γ pass rate of the original was 100% with 2.5 mm/2.5% as the statistical standard. The pass rate decreased to 95.9% and 89.4% when the X1 and X2 directions of the multileaf collimator were opened within 0.3 and 0.5 mm, respectively. In the field size of 7.00 (X) cm × 6.00 (Y) cm with 1.5 mm/1.5% as the statistical standard, the pass rate of the original was 96.5%. After X1 and X2 of the multileaf collimator were opened within 0.3 mm, the pass rate decreased to lower than 95%. The pass rate was higher than 90% within the 3 mm opening. (2) For spinal tumor, the change in the planning target volume V18 under various modes calculated using treatment planning system was within 1%. However, the maximum dose deviation of the spinal cord was high. In the spinal cord with a gravity of −0.25 mm, the maximum dose deviation minimally changed and increased by 6.8% than that of the original. In the largest opening of 1.00 mm, the deviation increased by 47.7% than that of the original. Moreover, the pass rate of the original determined through Delt 4 was 100% with 3 mm/3% as the statistical standard. The pass rate was 97.5% in the 0.25 mm opening and higher than 95% in the 0.5 mm opening A, 0.25 mm opening A, whole gravity series, and 0.20 mm random opening. Moreover, the pass rate was higher than 90% with 2.0 mm/2.0% as the statistical standard in the original and in the 0.25 mm gravity. The difference in the pass rates was not statistically significant among the −0.25 mm gravity, 0.25 mm opening A, 0.20 mm random opening, and original as calculated using SPSS 11.0 software with P > .05. Conclusions: Different analysis standards of Delt 4 were analyzed in different field sizes to improve the detection sensitivity of the multileaf collimator position on the basis of 90% throughout rate. In stereotactic body radiation therapy of spinal tumor, the 2.0 mm/2.0% standard can reveal the dosimetric differences caused by the minor multileaf collimator position compared with the 3.0 mm/3.0% statistical standard. However, some position derivations of the misalignments that caused high dose amount to the spinal cord cannot be detected. However, some misalignments were not detected when a large number of multileaf collimator were administered into the spinal cord.

Metal artifact reduction through MVCBCT and kVCT in radiotherapy

This study proposes a new method for removal of metal artifacts from megavoltage cone beam computed tomography (MVCBCT) and kilovoltage CT (kVCT) images. Both images were combined to obtain prior image, which was forward projected to obtain surrogate data and replace metal trace in the uncorrected kVCT image. The corrected image was then reconstructed through filtered back projection. A similar radiotherapy plan was designed using the theoretical CT image, the uncorrected kVCT image, and the corrected image. The corrected images removed most metal artifacts, and the CT values were accurate. The corrected image also distinguished the hollow circular hole at the center of the metal. The uncorrected kVCT image did not display the internal structure of the metal, and the hole was misclassified as metal portion. Dose distribution calculated based on the corrected image was similar to that based on the theoretical CT image. The calculated dose distribution also evidently differed between the uncorrected kVCT image and the theoretical CT image. The use of the combined kVCT and MVCBCT to obtain the prior image can distinctly improve the quality of CT images containing large metal implants.

Functions of the Mg–HA coating on carbon/carbon composite surface to promote the proliferation and osteogenic differentiation of mBMSCs

This study aims to evaluate the functions of the Mg–hydroxyapatite (Mg–HA) bio-coating on carbon/carbon composite (C/C) surface to promote the proliferation and osteogenic differentiation of bone mesenchymal stem cell (BMSCs). The Mg–HA-coated carbon/carbon composite was placed into a medium. The change of ion concentration in the solution and formation of bone-like apatite on the composite surface were observed. Thereafter, BMSCs of mice (mBMSCs) were cultivated on the coating surface for 4, 8, 24, 48, and 72 h. Finally, gene changes (i.e., Alp, OCN, Osx, and Runx2) related to cell proliferation and osteogenic differentiation were observed. The Mg–HA coating can form a bone-like apatite coating of high Mg concentration in the medium. After mBMSCs were cultivated on the Mg–HA coating for 72 h, mRNA of Alp, Osx, and Runx2 in Mg–HA was higher than that in the HA group (P 0.05). The Mg coating can significantly promote the proliferation and osteogenic differentiation of mBMSCs.