Comparison of endoscopic spine surgery and minimally invasive transforaminal lumbar interbody fusion for degenerative lumbar disease: A meta-analysis.

This study aimed to compare the clinical outcomes of endoscopic spinal surgery (ESS) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for degenerative lumbar disease (DLD) through meta-analysis. The Medline (via PubMed), Cochrane, Scopus, and Embase databases were searched for studies that evaluated the outcomes of ESS and MIS-TLIF in DLD, including visual analog scale (VAS) score for low back pain, VAS score for leg pain, Oswestry Disability Index (ODI), and complications published between January 2000 and August 2020. Two authors extracted the data independently. Any discrepancies were resolved by a consensus. Four comparative studies were identified. No significant differences were found between the ESS and MIS-TLIF groups in terms of VAS score for back pain, VAS score for leg pain, and ODI, except for complication rate. The complication rate was higher in the ESS than in the MIS-TLIF group. A literature review identified four comparative studies reporting the clinical outcomes of ESS and MIS-TLIF for DLD. Despite the heterogeneity, a limited number of meta-analyses showed that the clinical outcomes between the two groups were not significantly different except for complication rate. Hence, further large-scale multicenter studies are required to validate our results.

Production of pristine, sulfur-coated and silicon-alloyed germanium nanoparticles via laser pyrolysis.

Here we demonstrate production of three types of germanium containing nanoparticles (NPs) by laser pyrolysis of GeH4 and characterize their sizes, structures and composition. Pristine Ge NPs were fabricated with 50 standard cubic centimeter per minute (sccm) of GeH4 and 25 sccm of SF6 as a photosensitizer gas, while sulfur-coated Ge NPs were produced with 25 sccm of GeH4 and 50 sccm of SF6. The laser pyrolysis of SiH4/GeH4 mixtures produced Si1-xGex alloy NPs. Effects of key process parameters including laser intensity and gas flow rates on NP properties have been investigated. The ability of the laser pyrolysis technique to flexibly produce a variety of germanium-containing NPs, as illustrated in this study shows promise for commercial-scale production of new nanomaterials as high purity dry powders.

Capacity retention behavior and morphology evolution of SixGe1-x nanoparticles as lithium-ion battery anode.

Engineering silicon into nanostructures has been a well-adopted strategy to improve the cyclic performance of silicon as a lithium-ion battery anode. Here, we show that the electrode performance can be further improved by alloying silicon with germanium. We have evaluated the electrode performance of SixGe1-x nanoparticles (NPs) with different compositions. Experimentally, SixGe1-x NPs with compositions approaching Si50Ge50 are found to have better cyclic retention than both Si-rich and Ge-rich NPs. During the charge/discharge process, NP merging and Si-Ge homogenization are observed. In addition, a distinct morphology difference is observed after 100 cycles, which is believed to be responsible for the different capacity retention behavior. The present study on SixGe1-x alloy NPs sheds light on the development of Si-based electrode materials for stable operation in lithium-ion batteries (e.g., through a comprehensive design of material structure and chemical composition). The investigation of composition-dependent morphology evolution in the delithiated Li-SiGe ternary alloy also significantly broadens our understanding of dealloying in complex systems, and it is complementary to the well-established understanding of dealloying behavior in binary systems (e.g., Au-Ag alloys).