First-Principles Investigations on the Semiconductor-to-Metal Phase Transition of 2D SiTe for Reversible Resistive Switching.

SiTe is attracting attention due to its compatibility with Si technology while still showing advantages as a two-dimensional layered material. Although recent experimental studies have observed the resistive switching process in SiTe-based memristors, the mechanism has not been clearly identified. In this study, first-principles density functional theory calculations are employed to understand the relationship between the phase transition of SiTe and the reversible resistive switching of the SiTe-based memristor.

Cooperative coupling of anisotropic phonon modes intensifies visible thermochromism in layered α-MoO.

Applications that provide versatile, high temperature warnings require the development of thermochromic materials based on solid-state oxides. To boost the visible thermochromic properties, a fundamental approach to reveal the unclear roles of local structure on band structure modulation should be considered by scrutinizing the thermal motion of phonon modes. Herein, we demonstrate that selective coupling of intra-layer phonon modes intensifies the visible thermochromism of layered oxides α-MoO.

Highly Stable Germanium Microparticle Anodes with a Hybrid Conductive Shell for High Volumetric and Fast Lithium Storage.

The ability to realize a highly capacitive/conductive electrode is an essential factor in large-scale devices, requiring a high-power/energy density system. Germanium is a feasible candidate as an anode material of lithium-ion batteries to meet the demands. However, the application is constrained due to low charge conductivity and large volume change on cycles.

A-Site Effect on the Oxidation Process of Sn-Halide Perovskite: First-Principles Calculations.

Tin-halide perovskite solar cells (Sn-PSCs) are promising candidates as an alternative to toxic lead-halide PSCs. However, Sn is easily oxidized to Sn, so Sn-PSCs are unstable in air. Here, we use first-principles density functional theory calculations to elucidate the oxidation process of Sn at the surface of ASnBr [A = Cs or CHNH (MA)].

First-Principles Investigations to Evaluate the Spin-Polarized Metal-to-Insulator Transition of Halide Cuprite Perovskites for Smart Windows.

Although smart windows have received wide attention as energy-saving devices, conventional metal-to-insulator materials such as VO hinder their commercial usage because of their high transition temperature and low solar energy modulation. Further development can be achieved by finding a new material system that can effectively overcome these limitations. In this study, first-principles density functional theory calculations are used to investigate the possibility of exploiting a spin-polarized band gap material for smart window applications.

Electron-hole separation in ferroelectric oxides for efficient photovoltaic responses.

Despite their potential to exceed the theoretical Shockley-Queisser limit, ferroelectric photovoltaics (FPVs) have performed inefficiently due to their extremely low photocurrents. Incorporating BiFeCrO (BFCO) as the light absorber in FPVs has recently led to impressively high and record photocurrents [Nechache R, et al. (2015) 9:61-67], which has revived the FPV field.

Hydrogen-doped Brookite TiO Nanobullets Array as a Novel Photoanode for Efficient Solar Water Splitting.

As a representative photocatalyst for photoelectrochemical solar water splitting, TiO has been intensively studied but most researches have focused on the rutile and anatsase phases because brookite, another important crystalline polymorph of TiO, rarely exists in nature and is difficult to synthesize. In this work, hydrogen doped brookite (H:brookite) nanobullet arrays were synthesized via a well-designed solution reaction for the first time. H:brookite shows highly improved PEC properties with excellent stability, enhanced photocurrent, and significantly high Faradaic efficiency for overall solar water splitting.

The nature of hydrogen-bonding interaction in the prototypic hybrid halide perovskite, tetragonal CH3NH3PbI3.

In spite of the key role of hydrogen bonding in the structural stabilization of the prototypic hybrid halide perovskite, CH3NH3PbI3 (MAPbI3), little progress has been made in our in-depth understanding of the hydrogen-bonding interaction between the MA(+)-ion and the iodide ions in the PbI6-octahedron network. Herein, we show that there exist two distinct types of the hydrogen-bonding interaction, naming α- and β-modes, in the tetragonal MAPbI3 on the basis of symmetry argument and density-functional theory calculations. The computed Kohn-Sham (K-S) energy difference between these two interaction modes is 45.

A Biomechanical Analysis of an Artificial Disc With a Shock-absorbing Core Property by Using Whole-cervical Spine Finite Element Analysis.

Study Design: A biomechanical comparison among the intact C2 to C7 segments, the C5 to C6 segments implanted with fusion cage, and three different artificial disc replacements (ADRs) by finite element (FE) model creation reflecting the entire cervical spine below C2.

Objective: The aim of this study was to analyze the biomechanical changes in subaxial cervical spine after ADR and to verify the efficacy of a new mobile core artificial disc Baguera C that is designed to absorb shock.

Summary Of Background Data: Scarce references could be found and compared regarding the cervical ADR devices' biomechanical differences that are consequently related to their different clinical results.

Clinical significance of achieving a flexion limitation with a tension band system in grade 1 degenerative spondylolisthesis: a minimum 5-year follow-up.

Study Design: Retrospective clinical study.

Objective: To evaluate the effect of the limitation of flexion rotation clinically and radiologically after interspinous soft stabilization using a tension band system in grade 1 degenerative spondylolisthesis.

Summary Of Background Data: Although several studies have been published on the clinical effects of limiting rotatory motion using tension band systems, which mainly targets the limitation of flexion rather than that of extension, they were confined to the category of pedicle screw-based systems, revealing inconsistent long-term outcomes.

Unsuccessful percutaneous endoscopic lumbar discectomy: a single-center experience of 10,228 cases.

Background: Percutaneous endoscopic lumbar discectomy (PELD) has remarkably evolved with successful results. Although PELD has gained popularity for the treatment of herniated disc (HD), the risk of surgical failure may be a major obstacle to performing PELD. We analyzed unsuccessful cases requiring reoperation.

Clinical and radiographic changes after percutaneous endoscopic cervical discectomy: a long-term follow-up.

Objective: Results following anterior cervical discectomy (ACD) without fusion are not well reported because of skepticism that the disturbed cervical spine anatomy after ACD might compromise clinical outcome. The purpose of this study was to determine whether ACD without fusion prompts the degenerative process significantly, and whether it is necessary to preserve disc height and cervical alignment for the sake of better clinical outcome following cervical spine surgery.

Background Data: Out of 56 consecutive patients, 37 patients who replied and consequently underwent postoperative MRI from April to June 2009 were included in this study.

The efficacy of hydroxyapatite for screw augmentation in osteoporotic patients.

The stability of screw constructs is of considerable importance in determining the outcome, especially in spinal osteoporosis. Polymethylmethacrylate (PMMA) has been proven as an effective material for increasing the pullout strength of pedicle screws inserted into the osteoporotic bones. However, PMMA has several disadvantages, such as its exothermic properties, the risk of neural injury in the event of extravasation, and difficulties in performing revision surgery.

Comparison of cervical kinematics between patients with cervical artificial disc replacement and anterior cervical discectomy and fusion for cervical disc herniation.

Background Context: Although anterior cervical discectomy and fusion (ACDF) is an effective treatment option for patients with cervical disc herniation, it limits cervical range of motion, which sometimes causes discomfort and leads to biomechanical stress at neighboring segments. In contrast, cervical artificial disc replacement (ADR) is supposed to preserve normal cervical range of motion than ACDF. A biomechanical measurement is necessary to identify the advantages and clinical implications of ADR.

Radiation exposure to the surgeon during percutaneous endoscopic lumbar discectomy: a prospective study.

Study Design: A prospective study.

Objective: The purpose of this study was to determine the radiation dose to which the surgeons are exposed during percutaneous endoscopic lumbar discectomy (PELD) and to calculate the allowable number of cases per year.

Summary Of Background Data: Transforaminal PELD is a minimally invasive technique for soft disc herniation.

Factors affecting clinical outcomes in treating patients with grade 1 degenerative spondylolisthesis using interspinous soft stabilization with a tension band system: a minimum 5-year follow-up.

Study Design: Retrospective clinical study.

Objective: To explore the factors influencing the clinical outcomes and motion-preserving stabilization after interspinous soft stabilization (ISS) with a tension band system for grade 1 degenerative spondylolisthesis (DS).

Summary Of Background Data: Despite increasing recognition of the benefits of dynamic stabilization systems for treating lumbar degenerative disorders, the factors affecting the clinical and radiological outcomes of these systems have rarely been identified.

Spinal meningeal melanocytoma in the S-1 nerve root sheath with paraspinal extension mimicking schwannoma.

Background: Spinal melanocytomas are variants that can be extradural or intradural and are most often located in the intradural extramedullary compartment of the main thecal sac as in schwannomas. However, origin of this variant from the pure peripheral compartment of rootlets is exceedingly rare.

Case Description: The authors present a case of spinal melanocytoma with confusing pathologic and radiologic features.

Cervical radiculopathy caused by vertebral artery loop formation : a case report and review of the literature.

Vertebral artery loop formation causing encroachment on cervical neural foramen and canal is a rare cause of cervical radiculopathy. We report a case of 61-year-old woman with vertebral artery loop formation who presented with right shoulder pain radiating to her arm for 2 years. Plain radiograph and computed tomography scan revealed widening of the right intervertebral foramen at the C5-6 level.

Comparison of multilevel oblique corpectomy with and without image guided navigation for multi-segmental cervical spondylotic myelopathy.

Objective: Multilevel Oblique Corpectomy (MOC) is an emerging technique for surgical treatment of multi-segmental cervical spondylotic myelopathy (CSM) featuring extensive ossification of the posterior longitudinal ligament (OPLL). However, the use of an oblique drilling plane is unfamiliar to most surgeons and there is no anatomical landmark present on the posterior portion of the vertebral body. To overcome these difficulties, the authors used intraoperative C-arm-based image guided navigation (IGN), and this study was conducted to evaluate the efficacy of IGN in MOC.

Dural tears in percutaneous endoscopic lumbar discectomy.

The objective of the study was to demonstrate the clinical characteristics of dural tears during percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent this unintended complication. The study used data from 816 consecutive patients who underwent PELD between 2003 and 2007. A total of nine patients (1.

Spinopelvic alignment after interspinous soft stabilization with a tension band system in grade 1 degenerative lumbar spondylolisthesis.

Study Design: Retrospective clinical study.

Objective: The purpose of this study was to examine the changes in spinopelvic alignment after interspinous soft stabilization (ISS) with a tension band system and to identify the lumbosacral parameters related to those changes and to determine their impact on the clinical outcomes compared with posterior lumbar interbody fusion (PLIF) in patients with low-grade degenerative spondylolisthesis (DS).

Summary Of Background Data: The sacropelvic morphometric changes after fusion surgery have received much research attention.

Postoperative retroperitoneal hematoma following transforaminal percutaneous endoscopic lumbar discectomy.

Object: The purpose of this study was to demonstrate the clinical characteristics of postoperative retroperitoneal hematoma (RPH) following transforaminal percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent the complication of unintended hemorrhage.

Methods: The medical records of 412 consecutive patients treated with transforaminal PELD between January 2005 and May 2007 were reviewed. A total of 4 patients (0.

Transforaminal percutaneous endoscopic lumbar discectomy for upper lumbar disc herniation: clinical outcome, prognostic factors, and technical consideration.

Background: Compared with lower lumbar disc herniations, upper lumbar disc herniations at L1-L2 and L2-L3 have specific characteristics that result in different surgical outcomes after conventional open discectomy. There are no published studies on the feasibility of percutaneous endoscopic lumbar discectomy for upper lumbar disc herniation. The purpose of this study was to assess the clinical outcome, prognostic factors and the technical pitfalls of PELD for upper lumbar disc herniation.

Spinal cord glioblastoma multiforme of conus medullaris masquerading as high lumbar disk herniation.

Background: A case of primary intramedullary glioblastoma occurring at conus medullaris is presented, which was initially undetected and misdiagnosed as L1 through L2 disk herniation.

Case Description: After the performance of L1 through L2 discectomy, the patient's initial painful symptom did not subside. The patient then developed a progressive paraparesis.