Factors Affecting Cage Obliquity and the Relationship between Cage Obliquity and Radiological Outcomes in Oblique Lateral Interbody Fusion at the L4-L5 Level.

OBJECTIVE: This retrospective study investigated the factors that affect cage obliquity angle despite orthogonal maneuvers performed during oblique lateral interbody fusion (OLIF) and assessed the relationship between cage obliquity angle and radiological outcomes post-surgery. METHODS: Twenty-nine males who underwent L4-L5 OLIF for lumbar degenerative disease between 2019 and 2021 with a followup duration greater than 12 months were analyzed. Radiological parameters were measured including psoas muscle volume, total psoas area index (total psoas muscle area [cm2]/height squared [m2]), distance from the iliac artery to the origin of the psoas muscle (DIAPM), angle between the origin of the psoas muscle and the center of the vertebral disc (APCVD), iliac crest height, disc height, lumbar flexibility (lumbar flexion angle minus extension angle), cage location ratio, cage-induced segmental lumbar lordosis (LL) (postoperative index level segmental LL minus used cage angle), foraminal height changes, fusion grade. RESULTS: DIAPM, APCVD, iliac crest height, postoperative index level segmental LL, and cage-induced segmental LL were significantly correlated with OLIF cage obliquity angle. However, other radiological parameters did not correlate with cage obliquity. Based on multiple regression analysis, the predictive equation for the OLIF cage obliquity angle was 13.062-0.318×DIAPM+0.325×A PCVD+0.174×iliac crest height. The greater the cage obliquity, the smaller the segmental LL compared to the cage angle used. CONCLUSION: At the L4-L5 level, OLIF cage obliquity was affected by DIAPM, APCVD, and iliac crest height, and as the cage obliquity angle increases, LL agnle achievable by the used cage could not be obtained.

Exploring research trends of technology use in mathematics education: A scoping review using topic modeling.

This study performed a scoping review of the literature concerning the use of technology in mathematics education published between January 1981 and March 2022 to explore research trends. After the defined filtering process, we retrieved 2,433 articles from Web of Science, ERIC, and PsycInfo databases and employed Latent Dirichlet Allocation (LDA) topic modeling to extract key terms and topics from the selected articles. The analysis focused on the four aspects: (a) evolution of research trends of technology use in mathematics education, (b) frequently used words, (c) latent research topics, and (d) research trends for particular topics. The findings revealed a steady increase in research interest, and the combination of frequently used words in the article abstracts suggests popular research topics that have been studied during the set period. The results of LDA identified seven research topics that were not precisely aligned with those identified in prior studies on mathematics education or educational technology. This implied technology integration into mathematics education as a distinctive research area. Over time, the seven topics showed different research trends (stable, fluctuating, increasing, and decreasing). We discussed plausible reasons for these varied patterns and proposed implications based on the research findings.

Progression of Ossification of Posterior Longitudinal Ligament After Anterior Cervical Discectomy and Fusion in Military Patients Exposed to Minor Trauma.

Objective: Ossification of the posterior longitudinal ligament (OPLL) can progress even after cervical spine surgery and may cause neurological injury as a result of minor trauma. The purpose of this study was to investigate the preventive factors associated with OPLL progression after anterior cervical discectomy and fusion (ACDF), a procedure commonly performed in clinical practice. Methods: We retrospectively investigated 295 male soldiers who underwent ACDF surgery between 2012 and 2017. Patients who were followed up for >12 months using dynamic radiography and computed tomography (CT) were included in the study. Radiological parameters investigated included OPLL progression, C2-C7 angles on dynamic radiography, segmental angles, C2-C7 cervical sagittal vertical axis (C2-C7 SVA), and the T1 slope. These parameters were measured preoperatively and 1 year postoperatively. Results: A total of 49 patients were enrolled, and 10 patients were confirmed to have OPLL progression. Comparison between the OPLL progression and non-progression groups showed no statistically significant differences in pre- and postoperative cervical range of motion. However, statistically significant differences were observed in the postoperative neutral C2-C7 angle (progression -3.9°±6.4° vs. non-progression -13.4°±7.9°, p=0.001) and the SVA change (progression 5.8±7.9 mm vs. non-progression -3.7±6.3 mm, p=0.00). The cutoff values were -8.01° for the postoperative neutral C2-C7 angle and 1.4 mm for SVA changes. Conclusion: Increased SVA (>1.4 mm) and a small postoperative neutral C2-C7 angle (>-8.01°) 1 year after ACDF were associated with OPLL progression. It is important to be mindful of these factors during follow-up after ACDF, because additional surgical treatment may be necessary for OPLL progression due to neurological injury caused by minor trauma.

Tailoring of TiAl6V4 Surface Nanostructure for Enhanced In Vitro Osteoblast Response via Gas/Solid (Non-Line-of-Sight) Oxidation/Reduction Reactions.

An aging global population is accelerating the need for better, longer-lasting orthopaedic and dental implants. Additive manufacturing can provide patient-specific, titanium-alloy-based implants with tailored, three-dimensional, bone-like architecture. Studies using two-dimensional substrates have demonstrated that osteoblastic differentiation of bone marrow stromal cells (MSCs) is enhanced on surfaces possessing hierarchical macro/micro/nano-scale roughness that mimics the topography of osteoclast resorption pits on the bone surface. Conventional machined implants with these surfaces exhibit successful osseointegration, but the complex architectures produced by 3D printing make consistent nanoscale surface texturing difficult to achieve, and current line-of-sight methods used to roughen titanium alloy surfaces cannot reach all internal surfaces. Here, we demonstrate a new, non-line-of-sight, gas/solid-reaction-based process capable of generating well-controlled nanotopographies on all open (gas-exposed) surfaces of titanium alloy implants. Dense 3D-printed titanium-aluminum-vanadium (TiAl6V4) substrates were used to evaluate the evolution of surface nanostructure for development of this process. Substrates were either polished to be smooth (for easier evaluation of surface nanostructure evolution) or grit-blasted and acid-etched to present a microrough biomimetic topography. An ultrathin (90 ± 16 nm) conformal, titania-based surface layer was first formed by thermal oxidation (600 °C, 6 h, air). A calciothermic reduction (CaR) reaction (700 °C, 1 h) was then used to convert the surface titania (TiO2) into thin layers of calcia (CaO, 77 ± 16 nm) and titanium (Ti, 51 ± 20 nm). Selective dissolution of the CaO layer (3 M acetic acid, 40 min) then yielded a thin nanoporous/nanorough Ti-based surface layer. The changes in surface nanostructure/chemistry after each step were confirmed by scanning and transmission electron microscopies with energy-dispersive X-ray analysis, X-ray diffraction, selected area electron diffraction, atomic force microscopy, and mass change analyses. In vitro studies indicated that human MSCs on CaR-modified microrough surfaces exhibited increased protein expression associated with osteoblast differentiation and promoted osteogenesis compared to unmodified microrough surfaces (increases of 387% in osteopontin, 210% in osteocalcin, 282% in bone morphogenic protein 2, 150% in bone morphogenic protein 4, 265% in osteoprotegerin, and 191% in vascular endothelial growth factor). This work suggests that this CaR-based technique can provide biomimetic topography on all biologically facing surfaces of complex, porous, additively manufactured TiAl6V4 implants.

Highly Skin-Conformal Laser-Induced Graphene-Based Human Motion Monitoring Sensor.

Bio-compatible strain sensors based on elastomeric conductive polymer composites play pivotal roles in human monitoring devices. However, fabricating highly sensitive and skin-like (flexible and stretchable) strain sensors with broad working range is still an enormous challenge. Herein, we report on a novel fabrication technology for building elastomeric conductive skin-like composite by mixing polymer solutions. Our e-skin substrates were fabricated according to the weight of polydimethylsiloxane (PDMS) and photosensitive polyimide (PSPI) solutions, which could control substrate color. An e-skin and 3-D flexible strain sensor was developed with the formation of laser induced graphene (LIG) on the skin-like substrates. For a one-step process, Laser direct writing (LDW) was employed to construct superior durable LIG/PDMS/PSPI composites with a closed-pore porous structure. Graphene sheets of LIG coated on the closed-porous structure constitute a deformable conductive path. The LIG integrated with the closed-porous structure intensifies the deformation of the conductive network when tensile strain is applied, which enhances the sensitivity. Our sensor can efficiently monitor not only energetic human motions but also subtle oscillation and physiological signals for intelligent sound sensing. The skin-like strain sensor showed a perfect combination of ultrawide sensing range (120% strain), large sensitivity (gauge factor of ~380), short response time (90 ms) and recovery time (140 ms), as well as superior stability. Our sensor has great potential for innovative applications in wearable health-monitoring devices, robot tactile systems, and human-machine interface systems.

Droplet-Mediated Deterministic Microtransfer Printing: Water as a Temporary Adhesive.

Deterministic transfer printing of solid objects has been introduced and demonstrated, where capillary force based on water droplet has been utilized. Droplets on pickup head form capillary bridges with chips to be picked, where the capillarity provides enough force to grip or lift the chip. Release or printing of chips can be achieved by simply drying droplet while the chip is in contact with receiver substrate. That is, water droplet acts as a temporary adhesive, adheres onto solid chip by capillary force, and releases it upon drying. The technique has unique features such as self-alignment during pickup, self-correction on pickup head by short exposure to water mist, and pickup capability of solids having a nonflat, corrugated surface, all of which originated from the fluidic nature of water droplet. The technique has been successfully applied for the fabrication of stretchable micro-light-emitting diode chip arrays. The proposed technique can find wide applications in many fields such as displays, sensors, printed electronics, photovoltaics, etc.

Tunable multimodal adhesion of 3D, nanocrystalline CoFe2O4 pollen replicas.

3D replicas of sunflower pollen microparticles, comprised of a multicomponent magnetic spinel ferrite (CoFe2O4) with tailorable adhesive properties, have been synthesized for the first time via a conformal layer-by-layer (LbL) surface sol-gel (SSG) deposition process followed by organic pyrolysis and oxide compound formation at a peak temperature of 600 °C-900 °C. These high-fidelity ferrite pollen replicas exhibited multimodal (van der Waals, vdW, and magnetic) adhesion that could be tuned via control of the CoFe2O4 nanoparticle and crystal sizes. The CoFe2O4 pollen replicas exhibited a non-monotonic change in short-range (~10 nm) vdW adhesion with an increase in the peak firing temperature, which was consistent with the counteracting effects of particle coarsening on the size and number of nanoparticles present on the sharp tips of the echini (spines) on the pollen replica surfaces. The longer-range (up to ~1 mm) magnetic force of adhesion increased monotonically with an increase in firing temperature, which was consistent with the observed increases in the values of the saturation and remanent magnetization of CoFe2O4 with an increase in average nanocrystal size. By adjusting the nanocrystal/nanoparticle sizes of the CoFe2O4 pollen replicas, the total force of adhesion (vdW + magnetic) to a magnetic substrate could be increased by a factor of ~3 relative to native pollen grains.

Early Experience With a Partial Stapled Hemorrhoidopexy for Treating Patients With Grades III-IV Prolapsing Hemorrhoids.

PURPOSE: Circular stapled hemorrhoidopexy (CSH) is widely used to treat patients with grades III-IV hemorrhoids because of less pain and short hospital stay. However, this procedure is associated with some complications, such as urge to defecate, anal stenosis, staple line dehiscence, abscess and sepsis. To avoid these complications, surgeons perform a partial stapled hemorrhoidopexy (PSH). The aim of this study is to present our early experience with the PSH. METHODS: We retrospectively reviewed the medical records of 58 patients with hemorrhoids who were treated with a PSH at Busan Hang-Un Hospital from January 2016 to June 2016. A specially designed tri-window anoscope was used, and a purse string suture was made at the mucosae of the protruding hemorrhoids through the window of the anoscope. The hemorrhoidopexy was done by using a circular stapler. RESULTS: Of the 58 patients included in this study, 34 were male and 24 were female patients (mean age, 50.4 years). The mean operation time was 12.4 minutes, and the mean postoperative hospital stay was 3.8 days. Three patients experienced bleeding (5.1%) 5 urinary retention (8.6%) and 5 skin tags (8.6%). Urge to defecate, tenesmus, abscess, rectovaginal fistula, anal stricture, incontinence, and recurrence did not occur. CONCLUSION: PSH is a minimally invasive, feasible, and safe technique for treating patients with grades III-IV hemorrhoids. A PSH, instead of a CSH, can be used to treat certain patients with hemorrhoids.

Layer-modulated synthesis of uniform tungsten disulfide nanosheet using gas-phase precursors.

The synthesis of layered transition-metal-disulfide (MS2, M = Mo, W) nanosheets with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical devices. In this report, we describe a synthesis process of WS2 nanosheets with layer controllability and high uniformity using chemical vapor deposition (CVD) and WCl6 and H2S as gas-phase precursors. Through this process, we can systematically modulate the thickness of WS2 nanosheets by controlling the duration of the reaction between WCl6 and H2S. The CVD-grown WS2 nanosheets exhibit good stoichiometry as well as dependencies of a clear Raman shift and bandgap on the number of layers. These properties are confirmed by X-ray photoemission spectroscopy, Raman spectroscopy, and photoluminescence measurements. The number of layers of WS2 nanosheets is confirmed by atomic force microscopy. Finally, we demonstrate the fabrication and performance of a photodetector based on a hybrid structure consisting of graphene and a WS2 nanosheet.

Fibrin glue fixation for suction blister epidermal grafting in two patients with stable vitiligo.

Vitiligo is a chronic disorder characterized by depigmented macules which can slowly enlarge with the concurrent development of new lesions. Although autologous suction blister epidermal grafting is an established technique for the treatment of recalcitrant, stable vitiligo, the donor tissue graft is not easy to fix at the recipient site, especially in areas such as the joints, face, cutaneous folds, hands, feet, and hair-bearing areas. Therefore, various methods of donor tissue fixation have been attempted. We report two cases of vitiligo treated with suction blister epidermal grafting, with fibrin tissue adhesion. The first case is that of 16-year-old female patient presented with hypopigmented patches on the forehead and frontal scalp area. The other case is that of 32-year-old female patient presented with hypopigmented patches on the chin. We treated them with phototherapy for 1~4 years; however, the lesions were recalcitrant. Therefore, we tried treatment with a suction blister epidermal graft. Because graft fixation is difficult at the recipient sites, fibrin glue was sprayed on the grafts. Thereafter, we applied a porous silicone wound contact layer over the graft area and applied sterile gauze dressing that was left for a week. One week after the procedure, firm fixation of the donor tissue was observed in both cases. Fibrin glue seemed to improve the graft fixation, providng protection against infection and an optimal environment for wound healing. This report suggests that the application of an epidermal graft with fibrin glufixation, can provide the best result in the surgical treatment of stable vitiligo.

Silver thin film as a temporal template and dopant source for vertically aligned p-n homojunction of ZnO nanorods.

A silver thin film is introduced as a temporal template and dopant source for vertically aligned p-n homojunction of ZnO nanorods. The growth of Ag-doped ZnO nanorods was observed over time and the doping effect was determined through various characterization methods. Furthermore, a p-n homojunction diode of ZnO nanorods was fabricated.

Significance of C-reactive protein and transcranial Doppler in cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Cerebral vasospasm is a common and potentially devastating complication of aneurysmal subarachnoid hemorrhage (aSAH). Inflammatory processes seem to play a major role in the pathogenesis of vasospasm. C-reactive protein (CRP) constitutes a highly sensitive inflammatory marker. Elevation of serum CRP levels has been demonstrated in patients with aSAH. The purpose of the current study was to evaluate the possible relationship between CRP levels in the serum and transcranial Doppler (TCD) and the development of vasospasm in patients with aSAH. METHODS: A total of 61 adult patients in whom aSAH was diagnosed were included in the study from November 2008 to May 2011. The patients' demographics, Hunt and Hess grade, Fisher grade, CT scans, digital subtraction angiography studies, and daily neurological examinations were recorded. Serial serum CRP measurements were obtained on days 1, 3, 5, 7, 9, 11 and 13 and TCD was measured on days 3, 5, 7, 9, 11 and 13. All patients underwent either surgical or endovascular treatment within 24 hours of their hemorrhagic attacks. RESULTS: Serum CRP levels peaked on the 3rd postoperative day. There were significant differences between the vasospasm group and the non-vasospasm group on the 1st, 3rd and 5th day. There were significant differences between the vasospasm group and the non-vasospasm group on the 3rd day in the mean middle cerebral artery velocities on TCD. CONCLUSION: Patients with high levels of CRP on the 1st postoperative day and high velocity of mean TCD on the 3rd postoperative day may require closer observation to monitor for the development of vasospasm.

Layer-controlled, wafer-scale, and conformal synthesis of tungsten disulfide nanosheets using atomic layer deposition.

The synthesis of atomically thin transition-metal disulfides (MS2) with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical devices. In this work, we describe a process for the synthesis of WS2 nanosheets through the sulfurization of an atomic layer deposition (ALD) WO3 film with systematic layer controllability and wafer-level uniformity. The X-ray photoemission spectroscopy, Raman, and photoluminescence measurements exhibit that the ALD-based WS2 nanosheets have good stoichiometry, clear Raman shift, and bandgap dependence as a function of the number of layers. The electron mobility of the monolayer WS2 measured using a field-effect transistor (FET) with a high-k dielectric gate insulator is shown to be better than that of CVD-grown WS2, and the subthreshold swing is comparable to that of an exfoliated MoS2 FET device. Moreover, by utilizing the high conformality of the ALD process, we have developed a process for the fabrication of WS2 nanotubes.