Therapeutic Effect of Artificial Femoral Head Replacement and Proximal Femoral Nail Antirotation on Elderly Unstable Intertrochanteric Fractures

Objective: To compare the clinical efficacy of artificial femoral head replacement and Proximal femoral nail antirotation (PFNA) in the treatment of unstable femoral intertrochanteric fractures in the elderly. Methods: This study retrospectively analyzed 60 elderly patients with unstable intertrochanteric fractures treated with PFNA and artificial femoral head replacement from 2015.06 to 2018.06, of which 34 were in the PFNA group (Group A) and 26 in the artificial femoral head replacement group (Group B). Statistical analysis of relevant surgical indicators such as surgical time, intraoperative blood loss, postoperative blood transfusion, postoperative time to landing, postoperative infection rate, hospital stay, number of secondary operations, postoperative VAS score, and postoperative Hip function score comparison. Results: All 60 patients were followed up for 1 - 24 months. Compared with the artificial femoral head replacement group, the operation time of PFNA group was shorter, the blood loss during operation was less, and the difference was statistically significant (P 0.05). Conclusion: The hip joint function and pain scores of the artificial femoral head replacement group in the early and follow-up periods are better than those of the PFNA group. The artificial femoral head replacement is more suitable for the treatment of elderly unstable intertrochanteric fractures.

A Case of Premature Ventricular Complexes from the Proximal Left Bundle Branch Successfully Ablated from the Right Coronary Cusp

Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of successful ablation of PVCs from the proximal LBB within the right coronary cusp(RCC).Case presentation:Our patient was a 70-year-old woman with PVCs from the proximal LBB that were successfully ablated via the RCC through radiofrequency catheter ablation with a 3D mapping system;she had a complication of incomplete right bundle branch block(RBBB)and remained asymptomatic during follow-up.Conclusion:The RCC provides an alternative approach for ablating PVCs originating from the proximal LBB,ow-ing to the close relationship between the RCC and proximal LBB.

Enhanced electrocaloric strength in P(VDF-TrFE-CFE) by decreasing the crystalline size

Through the modulation of the dipolar entropy under an applied electric field(E),a reversible temperature change(ΔT)could be achieved in a dielectric material,which is known as the electrocaloric(EC)effect.Among all EC materials,ferroelectric terpolymer P(VDF-TrFE-CFE)has been regarded as one of the most promising EC materials owing to its large EC effect and superior thermal stability.Yet,the low EC strength limits the application of terpolymers in realistic cooling devices.In this work,using the thermal treatment of quenching and low-temperature annealing,the terpolymers with significantly decreased crystalline size are prepared with their EC performances investigated.Compared to the normal ones,the terpolymers with smaller crystalline size exhibit substantially enhanced EC strength.The better EC performance may be mainly attributed to the lower energy barriers for dipole orientation,which gives rise to higher polarization at low electric fields.This work emphasizes the critical role of crystalline size on the macroscopic properties of EC polymers.

High electrocaloric cooling power of relaxor ferroelectric BaZr_xTi_(1–x)O_3 ceramics within broad temperature range

Electrocaloric effect （ECE） is much promising to realize high efficiency and environment friendly solution in solid cooling devices. Relaxor ferroelectrics are good candidates for the materials with high elec-trocaloric cooling power. In this paper, relaxor ferroelectric Ba（ZrxTil_x）O3 （BZT, x = 0.2, 0.21, 0.22, 0.23） ceramics were prepared with their temperature change （AT） induced by the ECE and electrocaloric strength （AT/E） measured within broad temperature range. It is found that the BZT21 （x = 0.21) exhibits the largest ATof-4.67 K and a high AT/E value of-0.46 km/MV at 9.9 MV/m and 25℃. BZT21 also exhi-bits apparent relaxor ferroelectric response, showing a very broad EC peak in the temperature interval between 15℃ and 50℃. Moreover, the relationship between EC properties and relaxor features was analyzed by piezoresponse force microscopy test. The results reveal that more dispersed phase structures induce additional configurational entropy, which is in favor for the enhanced EC performance. The inter-play and compromise between the kinetic and thermodynamic mechanisms of domain switching deter-mines the optimal composition for the EC performances of the BZT ceramics.