Bio-medical materials and engineering最新文献

Background: Percutaneous kyphoplasty (PKP) or percutaneous vertebroplasty (PVP) are commonly employed for Kummell's disease in stages II-III; however, these techniques produce some complications.

Objective: To compare the clinical efficacy and imaging results of percutaneous vertebroplasty + bone cement-augmented short-segment pedicle screw fixation (PSPVP) versus transpedicular intracorporeal bone grafting + pedicle screw fixation (PSIBG) in the treatment of stage II-III Kummell's disease.

Methods: A total of 69 patients admitted between November 2017 and March 2021 were included in this study; 36 of these were treated with PSPVP, and 33 were treated with PSIBG. Patients in the two groups were compared in terms of perioperative, follow-up, and imaging data.

Results: No statistically significant differences were found between the two groups in terms of operation duration (P > 0.05). However, the PSPVP group was superior to the PSIBG group in terms of incision length, intraoperative blood loss, and length of stay (P < 0.05). All patients were followed up for more than 12 months. The VAS score, height of anterior vertebral margin, kyphosis Cobb angle, wedge angle of the affected vertebra at seven days after surgery and last follow-up, and the ODI index at the last follow-up of the two groups were significantly improved compared with figures before surgery (P < 0.05). Compared with values before surgery, no statistically significant differences were found in the height of the posterior vertebral margin in the PSPVP group at seven days after surgery and at the last follow-up (P > 0.05). There were also no statistically significant differences in the VAS score, ODI index, kyphosis Cobb angle, and wedge angle of the affected vertebra between the two groups at corresponding time points (P > 0.05). The heights of the anterior and posterior vertebral margins in the PSIBG group were better than those in the PSPVP group after surgery and at the last follow-up (P < 0.05). In the PSPVP group, a pedicle screw fracture occurred in one patient two months after surgery, while an upper adjacent vertebral fracture occurred in one patient eight months after surgery.

Conclusion: Both PSPVP and PSIBG can achieve good early clinical efficacy in the treatment of stage II-III Kummell's disease, with PSPVP being relatively less invasive while producing a poorer orthopedic effect and more complications than PSIBG.

Background: Although the internal fixation technique for scoliosis is effective, there is a great risk of nail placement in actual operation.

Objective: To compare the effects of three different nail placement strategies on LenkeC patients with scoliosis under cyclic loading.

Methods: Firstly, the finite element model was established by using CT scanning images and X-ray images of patients with LenkeC scoliosis. Secondly, the validity of the model was verified. Finally, the harmonic response analysis and transient dynamic analysis were carried out.

Results: The results showed that the maximum amplitude of each vertebral body appeared in the Z direction at the third natural frequency and the amplitudes of each corresponding vertebral body were very close under three kinds of nail placement. Under different nail placement methods, the uneven distribution of nails would make the model produce obvious stress concentration, but the principal stress of vertebral body and nail rod was far lower than its own yield strength. This showed that under the axial cyclic load, the vertebral bodies of scoliosis tended to have larger impact in Z direction. From the point of view of dynamics, it was feasible to reduce a certain number of nails in operation.

Conclusion: This paper revealed that it was feasible to reduce a certain number of nails during surgery.

Background: Hydrogel is a three-dimensional structure that has the potential to absorb and retain water within the mesh of its porous network structure. Currently hydrogels made from natural biopolymers are preferred in the discipline of biomedical applications because of their blood compatibility, adhesion of platelets and protein binding, ease of administration and delivery of ingredients to the place of action.

Objective: The aim of this work was to prepare a hydrogel from natural biopolymers and evaluate its blood compatibility, swelling nature, prolonged degradation and morphological features in order to further recommend its clinical use.

Methods: To prepare hydrogels, different combinations of gelatin, dialyzed SF, curcumin and N, N methylene bisacrylamide (MBA) were evenly mixed on a magnetic stirrer. After an hour of the gelation process it was kept in a refrigerator at 4 °C. For the characterization and biocompatibility studies of hydrogel, the swelling test and biodegradation analysis, SEM, FTIR, in vitro coagulation tests, total serum albumin and cholesterol level analysis were applied.

Results: Injectable hydrogels were successfully made with significantly correlated combinations of polymers. The analysis of physiochemical biocompatibility studies and morphological characterization were done effectively.

Conclusion: The results of the study indicate that hydrogels made from natural biopolymers are a potential source and suitable matrices with excellent biocompatible nature acting as a useful device in delivering drugs.

Background: Pain related to the sacroiliac joint (SIJ) accounts for low back pain in 15%-30% of patients. One of the most common treatment options is the use of pelvic belts. Various types of pelvic belts exist; however, the mechanisms underlying treatment and their effectiveness remain unclear to date.

Objective: To analyze stress distribution in the pelvis when a pelvic rubber belt or a padded pelvic belt is applied, to assess the effectiveness of treatment from a numerical biomechanical perspective.

Methods: The pressure distribution at the pelvic belts was measured using a device and subsequently modeled with the finite element method of a pelvis with soft tissues. The stress environment when wearing a pelvic belt in a double-leg stance was simulated.

Results: With the application of pelvic belts, the innominate bone rotated outward, which was termed an out-flare. This caused the SIJ to compress and cause reduction in sacrotuberous, sacrospinous, interosseous, and posterior sacroiliac ligament loading. Padded pelvic belts decreased the SIJ displacement to a greater extent than in pelvic rubber belts.

Conclusion: Pelvic belts aid in compressing the SIJ and reduce its mobility.

Background: The COVID-19 pandemic has resulted in increased psychological pressure on mental health since 2019. The resulting anxiety and stress have permeated every aspect of life during confinement.

Objective: To provide psychologists with an unbiased measure that can aid in the preliminary diagnosis of anxiety disorders and be used as an initial treatment in cognitive-behavioral therapy, this article introduces automated recognition of three levels of anxiety.

Methods: Anxiety was elicited by exposing participants to virtual environments inspired by social situations in reference to the Liebowitz social anxiety scale. Relevant parameters, such as heart rate variability and vasoconstriction were derived from the measurement of the blood volume pulse (BVP) signal.

Results: A long short-term memory architecture achieved an accuracy of approximately 98% on the training and test set.

Conclusion: The generated model allowed for careful study of the state of seven phobic participants during virtual reality exposure (VRE).

Background: Acute liver failure is one of the most intractable clinical problems. The use of bioartificial livers may solve donor shortage problems. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an excellent seed cell choice for artificial livers because they change their characteristics to resemble hepatocyte-like cells (HLCs) following artificial liver transplantation.

Objective: This study aimed to determine whether the immunological characteristics of hUCMSCs are changed after being transformed into hepatocyte-like cells.

Methods: HUCMSCs were isolated by the adherent method. The following hUCMSC surface markers were detected using flow cytometry: CD45, CD90, CD105, CD34, and octamer-binding transcription factor 4 (OCT-4). Functional detection of adipogenic differentiation was performed. The hUCMSCs were cultured in complete medium (control group) or induction medium (induction group), and flow cytometry was used to detect cell surface markers. Peritoneal lavage fluid was collected after intraperitoneal injection of 1 × 106 cells/mouse over 40 minutes. The leukocyte count, labeled CD45, CD3, CD4 and CD8 antibodies, and flow detection of T lymphocyte subsets were determined using the peritoneal lavage fluid.

Results: Using phenotypic and functional identification, hUCMSCs were successfully isolated using a two-step induction method. The surface markers of the hUCMSCs cells changed after HLC induction. In vivo immune results showed that hUCMSCs and HLsC induced leukocyte production.

Conclusion: Hepatic induction of hUCMSCs changes their cell surface markers. Both HLCs and hUCMSCs cause leukocytosis in vivo, but the immune response induced by HLCs is slightly stronger.

Background: The marginal adaptation of root-end filling materials and the effective antibacterial control in a surgical site are crucial for the successful outcome of endodontic surgery.

Objective: This study aimed to evaluate the effect of retrograde application of photodynamic therapy on the marginal adaptation of Biodentine used as a root-end filling material.

Methods: Twenty single-rooted anterior teeth were selected, instrumented and obturated with gutta-percha and AH Plus. The apical 3 mm of the roots were resected and root-end cavities were prepared with an ultrasonic retro-tip. The teeth were randomly divided into two groups (n = 10). In the first group, photodynamic therapy (PDT) was applied in the retrograde cavity prior to the root-end filling. In the second group retro cavity was filled without PDT. All specimens were obturated with Biodentine and afterwards sectioned longitudinally. The gap width at the material-dentin interface was measured using a scanning electron microscope. The results were statistically analyzed.

Results: The produced gap width by Biodentine/PDT was 3.85 μm versus 2.68 μm in the Biodentine control group with significant differences in-between.

Conclusion: Under the conditions of this study, PDT has a negative effect on the marginal adaptation of Biodentine used as root-end filling material.

Background: Implantable devices such as ventricular assist devices provide appropriate treatment for patients with advanced heart failure. Unfortunately, these devices still have many problems, particularly related to blood damage.

Objective: The aim of this research is to examine two new ventricular assist devices in terms of induced shear stress, exposure time, and induced hemolysis.

Method: Reverse engineering was used on multiple axial flow ventricular assist devices to collect all the details related to the designs (diameters, lengths, blade angles…), which were used to build two prototypes: Model A and Model B.

Results: The obtained results were close to a large extent, except for static pressure rise, where the difference was clear.

Conclusion: Compared with what has been published in other studies, the overall performance of both models was excellent.

Background: The effect of casting parameters on the microstructure and corrosion resistance of Mg alloys is still limited, especially in clinical animal experiments.

Objective: We prepared a new magnesium rare earth alloy (Mg-Re, where Re is Ce or La) by vertical two-roll casting and Mg-A by further rolling. The microstructure characteristics, degradation behavior, and bone reaction of the two alloys were studied.

Method: Ti, Mg-Re, and Mg-A alloy plates were implanted in a rat femur model, and their degradation behavior was observed 48 weeks later.

Results: In vivo experiments showed no significant changes around the femur in the Ti group, excluding external factors that may cause bone remodeling and lead to new bone formation. Mg-A induces more new bone formation than Mg-Re, which meets the necessary conditions to prevent pathological fracture. The specimen staining and sectioning showed that the liver and heart of rats implanted with magnesium alloys had no pathological changes and the cell structure was normal, similar to that of rats without a magnesium alloy.

Conclusion: Mg-A alloy has good healing potential as a biodegradable implant material.