Search

Background: Percutaneous vertebroplasty (PVP) via various puncture approaches was an effective minimally invasive treatment for osteoporotic vertebral compression fractures (OVCFs). In recent years, unilateral puncture techniques had been increasingly used with advantages of shorter operation time, lower X-ray exposure. The aim of this study was to explore the safety and efficacy of the unilateral transforaminal approach (UTFA) in PVP for the treatment of OVCFs. Methods: A retrospective study was designed to review 155 cases of single-level OVCFs from July 2018 to December 2019. We treated 77 patients with PVP via the UTFA and 78 via the bilateral transpedicular approach (BTPA). Operation time, number of intraoperative fluoroscopic X-rays, volume of bone cement injection and distribution of bone cement were recorded. We used Visual Analog Scale (VAS) score and Oswestry disability index (ODI) presurgery and at 1 day, 3 months and last follow-up after surgery to assess clinical outcomes. Results: The operation was successfully completed in both groups, with no complications of neurovascular injuries or bone cement embolism. UTFA group had significantly shorter operation time and less-frequent fluoroscopy than BTPA group (P < 0.05). There were no significant differences between the two groups in volume or distribution of injected bone cement (P > 0.05). Postoperative VAS scores and ODI of the two groups were significantly improved over their presurgical values (P < 0.05), but there were no significant differences in VAS or ODI at each time point between the two groups (P > 0.05). Conclusions: Both unilateral transforaminal PVP and bilateral transpedicular PVP were safe and effective treatments for OVCFs, but the former approach had the advantages of shorter operation time and less X-ray radiation exposure and therefore is worthy of greater clinical application.

This paper proposes a general framework of multi-armed bandit (MAB) processes by introducing a type of restrictions on the switches among arms evolving in continuous time. The Gittins index process is constructed for any single arm subject to the restrictions on switches and then the optimality of the corresponding Gittins index rule is established. The Gittins indices defined in this paper are consistent with the ones for MAB processes in continuous time, integer time, semi-Markovian setting as well as general discrete time setting, so that the new theory covers the classical models as special cases and also applies to many other situations that have not yet been touched in the literature. While the proof of the optimality of Gittins index policies benefits from ideas in the existing theory of MAB processes in continuous time, new techniques are introduced which drastically simplify the proof., Comment: 27 pages, 0 figures

The chemical composition of essential oil obtained by hydrodistillation from the dried fruits of Chaenomeles speciosa was analyzed by GC–MS. Forty compounds, constituting about 85.13% of the total oil, were identified. The main constituents were β-caryophyllene (12.52%), α-terpineol (5.41%), terpinen-4-ol (4.56%) and 1,8-cineole (4.31%). The antimicrobial activity of the oil was evaluated against 10 microorganisms using disc diffusion and broth microdilution methods. The essential oil was found to show a broad spectrum of antimicrobial activity against all the tested bacterial strains. The essential oil had more sensitivity to gram-positive than gram-negative bacteria.

Two multilevel algorithms are developed to solve the problem of optimizing a large scale system Kith multiple delays. It is shown that the algorithms convert the problem, even if its cost function is nonseparable. into a sequence of independent subproblems of optimizing smaller subsystems without delays and a coordination problem of predicting interactions. The convergences of the algorithms are studied. By applying one of the algorithms to the economic operation problem of large hydrothermal power systems, we obtain a new computational method for this problem. A numerical example is solved to compare the computational efficiency of this method with that of a current one The results show that the former decreases the computation time on a large scale.

Two multilevel algorithms are developed to solve the problem of optimizing a large scale system with multiple delays. It is shown that the algorithms convert the problem, even if its cost function is nonseparable, into a sequence of independent subproblems of optimizing smaller subsystems without delays and a coordination problem of predicting interactions. The convergences of the algorithms are studied. By applying one of the algorithms to the economic operation problem of large hydrothermal power systems, we obtain a new computational method for this problem. A numerical example is solved to compare the computational efficiency of this method with that of a current one. The results show that the former decreases the computation time on a large scale.