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The purpose of this study was to evaluate the risk factors for subsequent fractures after distal radius fracture (DRF).We retrospectively reviewed 705 patients with DRF who performed dual-energy X-ray absorptiometry within six months before or after the DRF and followed more than 12 months. We identified patients with subsequent fractures and multivariate logistic regression analyses were conducted with demographic information, underlying disease status, and bone fragility parameters at the time of DRF to evaluate the risk factors for subsequent fractures.Subsequent fractures occurred in 56 patients (7.9% of 705 patients) with 65 fractures at a mean time of 33.5 months after DRF. In multivariate logistic regression analysis, older age (OR 1.032; 95% CI, 1.001-1.064, p = 0.044), diabetes mellitus (DM) (OR 2.663; 95% CI, 1.429-4.963, p = 0.002) and previous fracture history (OR 1.917; 95% CI, 1.019-3.607, p = 0.043), and low total hip BMD (OR 1.410; 95% CI, 1.083-1.836, p = 0.011) were significant risk factors for the occurrence of subsequent fractures.This study demonstrated that older age, DM, previous fracture history and low hip BMD are the risk factors for subsequent fractures after DRF. Active glycemic control would have a role in patients with DM and a more aggressive treat-to-target approach may be necessary for patients with low BMDs to prevent subsequent fractures after DRF.

We examine the effects of quantity‐based approaches to airport congestion management such as slot restrictions on price dispersion and on‐time performance. From the evidence at Newark Liberty International Airport, we find that slot restrictions increase price dispersion and improve on‐time performance. Price dispersion originates from heterogeneous price effects, as ticket prices for high‐value passengers increase more than that for low‐value passengers. Our novel finding is that the share of passengers who have purchased tickets at a top‐end price increase despite the price hike. We use various empirical specifications and an analysis on leads and lags of the policy for robustness.

Mechanisms of ceramic liner fractures have not yet been fully elucidated. Impingement between a stem and ceramic liner is a proposed cause of ceramic liner fractures. We experienced a case of ceramic liner fracture caused by direct impingement between the stem shoulder and the ceramic liner. This type of impingement, unlike impingements with a stem neck, has not been previously reported. While we assume that certain characteristics of the stem contributed to the impingement, we report this case to note that caution may be needed when using certain stem designs.

This study aimed to analyze the epidemiologic characteristics of patients who underwent hip arthroplasty using the Korean nationwide database and investigate the recent trends in implant fixation methods and bearing surface selection. We aimed to compare clinical characteristics and differences with the results from the registry of other western countries. We analyzed the data collected by the Health Insurance Review and Assessment Service database of Korea from 2007 to 2011 and the Main Surgery Statistical Yearbook from 2014 to 2018, published by the National Health Insurance Service. The number and rate of patients who underwent hip joint arthroplasty per 10,000 persons have been steadily increasing since 2007. There was a big difference in mean age and preoperative diagnosis of patients between the bipolar hemiarthroplasty and total hip arthroplasty groups. Most patients underwent surgery using a cementless biological fixation method, and the cemented fixation method was selectively used for a small portion of old aged osteoporotic patients. In relation to the use of bearing surfaces, the registry data showed that ceramic-ceramic bearings were used at an overwhelmingly high rate (81%) in Korea compared to other countries. The reason was attributable to various factors, such as patient’s age or economic status, differences in the health insurance system between countries, and recently reported complications, such as ceramic fracture or noise.

Background Dilute povidone-iodine (PI) lavage, a simple disinfection method, could reduce postoperative infection risk. However, there is no clinical consensus regarding its efficacy in total joint arthroplasties (TJAs). This systematic review and meta-analysis evaluated PI lavage’s efficacy in preventing infection after TJA. Methods MEDLINE, Embase, and the Cochrane Library were systematically searched for studies published before November 22, 2019, that compared postoperative infection rates in patients who underwent TJA with or without PI lavage before wound closure. Subgroup analyses were designed to identify the differences in infection site (overall or deep), type of surgery (total hip arthroplasty or total knee arthroplasty), time until diagnosis of infection (3 or 12 months postoperatively), and primary/aseptic revision arthroplasties. Results We included 7 studies with 31,213 TJA cases, comprising 8861 patients who received PI lavage and 22,352 who did not. Pooled odds ratio for overall infection rate for the PI and non-PI lavage groups was 0.67 (95% confidence interval, 0.38-1.19, P = .17) and for the deep infection rate was 0.90 (95% confidence interval, 0.27-2.98, P = .86). Subgroup analyses revealed no differences in postoperative infection rates between the PI and non-PI lavage groups in terms of total hip arthroplasty and total knee arthroplasty, diagnosis of infection at 3 and 12 months postoperatively, or primary and aseptic revision arthroplasties. Conclusion We detected no differences in the overall postoperative infection rates between the PI and non-PI lavage groups before wound closure in TJA including all studies in the subgroup analyses.

Quadratus lumborum block (QLB) has been shown to be effective for pain relief after hip surgery. This study evaluated the efficacy of ultrasound-guided anterior QLB in pain control after total replacement hip arthroplasty (TRHA). A total of 115 patients receiving anterior QLB were propensity score-matched with 115 patients who did not receive the block. The primary outcome was opioid consumption at 24, 24–48, and 48 postoperative hours. Secondary outcomes included pain scores at the post-anesthesia care unit (PACU), 8, 16, 24, 32, 40, and 48 h length of hospital stay, time to first ambulation, and the incidence of opioid-related side effects. Postoperative opioid consumption 48 h after surgery was significantly lower in the QLB group. Resting, mean, worst, and the difference of resting pain scores compared with preoperative values were significantly lower in the QLB group during the 48 postoperative hours. The length of hospital stay was shorter in the QLB group. The incidence of postoperative nausea and vomiting was significantly lower in the QLB group during the 48 postoperative hours, except at the PACU. This study suggests that anterior QLB provides effective postoperative analgesia for patients undergoing THRA performed using the posterolateral approach.

Incomplete fractures are assumed to occur in the intertrochanteric area as fractures at other sites, but reports of incomplete intertrochanteric fractures (IIFs) are rare. In 1999, Schultz et al. defined isolated greater trochanter fractures (GTFs) as IIFs when intertrochanteric extension is observed on magnetic resonance (MR) images. On multiplanar reformation computed tomography (MPR CT) images acquired for further study of apparently isolated GTFs, we noted incomplete cortical breakage in the intertrochanteric area. We then found that the fracture line was incomplete on plain radiographs in some intertrochanteric fractures. We evaluated IIFs and apparently isolated GTFs using MPR CT and analyzed the fracture patterns of IIFs that were confirmed using MPR CT.Between February 2006 and June 2019, 36 cases of IIF were detected using MPR CT in 36 patients. They were 17 women and 19 men with a mean age of 74.7 years (range, 26-94 years). Plain radiographs and MPR CT images were evaluated by two experienced orthopedic surgeons. In addition, MR imaging was performed in 5 cases.Plain radiographs showed no evidence of fracture in 2 cases, isolated GTF in 7 cases, and IIF in 27 cases. In all cases, incomplete cortical breakage in the intertrochanteric area was confirmed on MPR CT images. Cortical breakage was located in the anterior portion of the intertrochanteric area, whereas the posterior portion remained intact in all cases. The detection rate of cortical breakage was higher on coronal or sagittal images than that on axial images. On MR images of 5 cases, intertrochanteric extensions were found in the medullary space. All extensions originated in the greater trochanter area and extended anteriorly in the axial plane and inferomedially in the coronal plane. On the T1-weighted mid-coronal image, the extension reached or passed the midline in 3 cases, and cortical breakage was detected in only 2 cases.In all cases of IIF, cortical breakage was detected in the anterior portion of the proximal femur, leaving the posterior cortex intact. This finding is notably different from that of intertrochanteric extension (from posterior to anterior) detected on MR images of isolated GTFs.

Background It is assumed that impingement between the ceramic liner and the stem increases the possibility of a liner fracture in total hip arthroplasty with a ceramic-on-ceramic bearing. The purpose of this study was to analyze the pattern of the impingement by evaluating the notches (U-shaped indented wear scars engraved on the stem) on radiographs to determine when and where impingement develops and to analyze the factors affecting its occurrence. Methods Among the primary total hip arthroplasty cases using a ceramic-on-ceramic bearing performed from November 1997 to December 2003, 244 cases of 197 patients (123 male patients and 74 female patients) that had follow-up of ≥15 years were included. All of the radiographs were examined with special regard to the notches and the cup positions. Results Notches were detected at 77 sites of 57 cases (23.4%) for the first time between 8 months and 14.8 years after the surgical procedure. They were located on the neck or the shoulder of the stem. Shoulder notches were detected only in the cases with a short-neck head. Shoulder notches were found in 29 cases (20.0% of short-neck cases). Cup inclination was lower (p = 0.01) and anteversion was higher (p = 0.01) in the group with notches than the group without notches. There were 5 cases of ceramic head fracture. One of them experienced another ceramic liner fracture, assumed to be caused by prosthetic shoulder impingement, after the revision surgical procedure. Conclusions The results of this study suggest that impingement between the stem and the ceramic liner occurs in a considerable proportion of patients who underwent total hip arthroplasty not only on the neck but also on the shoulder of the stem. Forceful and abrupt impingement on the stem shoulder can cause ceramic liner fracture. Impingement between the stem shoulder and the ceramic liner should be considered in designing a stem. It seems to be prudent to recommend that patients avoid squatting or sitting cross-legged on the floor as much as possible. Level of evidence Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Presently, hip arthroscopy is a widely adopted surgical intervention for the treatment of femoroacetabular impingement (FAI). However, there is insufficient evidence regarding which between arthroscopy and nonoperative treatment is more optimal for symptomatic FAI. Methods: MEDLINE, Embase, Web of Science, and the Cochrane Library were systematically searched for studies that compared arthroscopy and nonoperative interventions for FAI treatment from inception to August 4, 2020. We included studies that directly compared surgical and nonsurgical treatment for symptomatic FAI and excluded those that did not use arthroscopic treatment as a surgical technique and studies performed on patients with concomitant diagnoses instead of pure FAI. We compared the following clinical outcome scores at 6 and 12 months of follow-up: International Hip Outcome Tool 33 (iHOT-33), hip outcome score (HOS), EuroQol-visual analog scale (EQ-VAS), modified Harris hip score (mHHS), and nonarthritic hip score (NAHS). Results: Five studies totaling 838 patients were included in the qualitative and quantitative synthesis; 382 patients underwent hip arthroscopy, and 456 patients were treated by nonoperative interventions. At 6 months of follow-up, there were no statistically significant differences in iHOT-33 ratings (mean difference [MD] = 7.92, P = .15), HOS (MD of HOS-ADL = 5.15, P = .26 and MD of HOS-Sports = 2.65, P = .79, respectively), and EQ-VAS (MD = 1.22, P = .76) between the 2 treatment strategies. At 12 months of follow-up, the arthroscopy group had a greater mean improvement in iHOT-33 score than the conservative treatment group (MD = 8.42, P = .002), but there was no difference between the groups in terms of mHHS rating (MD = −0.24, P = .83) and NAHS (MD = −2.08, P = .09). Conclusion: Despite arthroscopy being associated with significantly superior iHOT-33 scores after 12 months of follow-up, we were unable to discern the difference between the treatment strategies using other scoring methods, such as HOS, EQ-VAS, mHHS, and NAHS. Further studies will be needed to conclusively determine if 1 strategy is superior to the other for treating FAI.

Most isolated greater trochanter (IGT) fractures are treated conservatively. However, some require surgical fixation although indications for surgery have not yet been established. Many surgeons perform surgical fixation when the intertrochanteric extension crosses the midline on magnetic resonance (MR) images. Nevertheless, for mechanical strength, cortical bone integrity is more important than that of intramedullary cancellous trabeculae. We retrospectively evaluated the clinical usefulness of multiplanar reformation computed tomography (MPR CT) in determining treatment strategies for IGT fractures.We evaluated 99 cases of suspected IGT fractures between October 2004 and December 2019. They were 66 women and 33 men with a mean age of 77 years. The mean follow-up period was 34 months. Most patients were evaluated with plain radiographs, followed by additional imaging study via MPR CT in 65 cases, magnetic resonance imaging (MRI) in 5 cases, and both in 17 cases. Typically, fractures were fixed surgically when a cortical breakage was detected in the intertrochanteric area on MPR CT, while fractures without evidence of cortical breakage on MPR CT were treated conservatively.In 13 out of 82 cases evaluated by MPR CT, incomplete cortical breakage in the intertrochanteric area was detected, of which 10 were treated surgically. The remaining 3 cases were treated conservatively due to patient's refusal, poor medical condition, and failure to detect breakage. Of 69 cases without cortical breakage, 61 cases were successfully treated conservatively. Among the 17 cases evaluated by both MPR CT and MRI, cortical breakage was detected in 3, of which the intertrochanteric extension crossed the midline on the MR image only in 1 case. Of the remaining 14 cases without breakage, the intertrochanteric extension crossed the midline in 5. Among these 5 cases, 3 were treated conservatively.The results suggest that MPR CT is a useful imaging modality for further evaluation of IGT fractures. It was especially valuable in evaluating cortical bone integrity, which may be more critical for fracture stability.

The present study investigated the minimum 2-year outcomes of hip arthroscopy for femoroacetabular impingement (FAI) and concomitant labral tears in Asian patients.Patients who underwent hip arthroscopy for both FAI and concomitant labral tears between January 2012 and December 2017 were included. Patients with hip osteoarthritis of Tönnis grade ≥2, previous hip surgery, or followed for less than 2 years were excluded. Clinical assessments were performed using the modified Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, and the rates of achieving threshold values of the minimal clinically important difference and patient acceptable symptomatic state at the latest follow-up. Plain radiographs were acquired pre- and postoperatively for radiologic assessments.A total of 73 patients (90 hips, 58 male, 15 female; mean age 34.4 years) who underwent hip arthroscopy for FAI and concomitant labral tears were enrolled. Forty-three hips (47.8%) had cam-type, 7 (7.8%) had pincer-type, and 40 (44.4%) had mixed-type FAI. The mean follow-up duration was 5.2 years. In cam- and mixed-type FAI hips, the mean α angle significantly decreased from 66.7 ± 8.28° preoperatively to 44.9 ± 3.78° postoperatively (95% confidence interval [CI] 19.6°-22.8°; P.001). The mean modified Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index increased from 74.8 ± 13.2 and 75 ± 12.7 preoperatively to 93 ± 8.1 (95% CI 15.4-20.9; P = .001) and 89.4 ± 8.4 postoperatively (95% CI 11.8-17; P = .001), respectively. Seventy-four hips (82.2%) crossed the minimal clinically important difference, and 85 hips (94.4%) had achieved the patient acceptable symptomatic state. There were 2 cases of pudendal nerve palsy and 1 case of sciatic nerve palsy. No additional surgeries were required.Hip arthroscopy can be an effective treatment for FAI and concomitant labral tears in Asian patients as demonstrated in this study, with improved PRO scores and reoperation rates. Longer-term studies with larger cohorts are necessary.Level IV, case series.

BackgroundAcetabular labral tears cause of pain in patients with symptomatic hip dysplasia. To date, no structured grading system has been developed to evaluate labral tears in these patients. The present study describes a new system of grading labral tears in patients with acetabular dysplasia.MethodsThe data of 66 patients who underwent hip arthroscopy for symptomatic hip dysplasia from March 2014 to February 2018 were reviewed. Labral tears were classified into four groups, based on the occurrence of chondrolabral junction (CLJ) disruption, capsulolabral recess (CLR) disruption, and labral displacement. Labral tears without instability were classified as grade 1 or 2. Partial delamination or blistering of the labrum with minimal fraying at the CLJ was classified as grade 1, whereas labral tears with CLJ disruption were classified as grade 2. Unstable labral tears with CLR disruption followed by CLJ disruption, but without labral displacement, were classified as grade 3, whereas unstable labral tears with CLR and CLJ disruption, but with labral displacement, were classified as grade 4. The radiological and clinical characteristics of patients in each grade were determined including by simple radiographs and MRI/MR arthrography, as were concomitant findings, including rupture of the ligamentum teres, articular cartilage damage, and presence of a paralabral cyst. The surgical options selected for each grade and clinical outcomes, including modified Harris hip scores (mHHS) and Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) scores, were evaluated. Spearman's correlation analyses were performed to assess whether labral tear grade correlated with baseline characteristics, the incidence of concomitant injuries, and the severity of osteoarthritis (OA). The Wilcoxon test for paired data was performed to compare treatment results with pain scores.ResultsThe study cohort included six men and 53 women of mean ± SD age 39.9 ± 13.0 years (range, 15-66 years). Of the 66 hips, seven (10.6%), 10 (15.2%), 30 (45.5%), and 19 (28.8%) were classified as grades 1-4, respectively. Symptom duration (P = 0.017), preoperative Tönnis OA grade (P < 0.001), cartilage damage (P < 0.001), and the presence of a paralabral cyst (P = 0.001) correlated significantly with baseline tear grade. In all groups, mHHS and WOMAC scores improved after surgical treatment.ConclusionsArthroscopic findings of labral tears in patients with hip dysplasia differed from the conventional classification. The classification system proposed in this study will likely be useful for determining the degree of labral tear in patients with hip dysplasia and for predicting treatment outcomes.

We provide a novel approach of estimating a regime-switching nonlinear and non-Gaussian state-space model based on a particle learning scheme. In particular, we extend the particle learning method in Liu, J., and M. West. 2001. “Combined Parameter and State Estimation in Simulation-Based Filtering.” In Sequential Monte Carlo Methods in Practice, 197–223. Springer. by constructing a new proposal distribution for the latent regime index variable that incorporates all available information contained in the current and past observations. The Monte Carlo simulation result implies that our approach categorically outperforms a popular existing algorithm. For empirical illustration, the proposed algorithm is used to analyze the underlying dynamics of US excess stock return.

We show that the efficacy of fiscal decentralization in enhancing economic growth and labor productivity growth depends on whether taxes are collected at the central level or at the sub-national level. To empirically examine the differential effects, we introduce a distinct measure of fiscal decentralization that serves as a proxy for taxes collected at the sub-national level. While the proposed measure is used to investigate a specific question, the measurement itself is general and practical in nature. In addition to proposing a new proxy for fiscal decentralization, we evaluate the permanent impact of fiscal decentralization; consider heterogeneity in parameters by federalism status and income levels; and incorporate nonlinearity. Our finding suggests that neither a complete revenue decentralization nor centralization is optimal.

The conventional audio fingerprinting system by Haitsma uses a lookup table to identify the candidate songs in the database, which contains the sub-fingerprints of songs, and searches the candidates to find a song whose bit error rate is the lowest. However, this approach has a drawback that the number of database accesses increases dramatically, especially when the database contains a large number of songs or when a matching sub-fingerprint is not found in the lookup table due to a heavily degraded input signal. In this paper, a novel search method is proposed to overcome these difficulties. The proposed method partitions each song found from the lookup table into blocks, assigns a weight to each block, and uses the weight as a search priority to speed up the search process while reducing the number of database accesses. Various results from our experiment show the significant improvement in search speed while maintaining the search accuracy comparable to the conventional method.

Three-dimensional (3-D) Nb 2 O 5 nanotube layers with honeycomb structures were successfully synthesized using polystyrene (PS) microsphere templates and NbO x nanocrystals. A densely packed monolayer of monodisperse PS microspheres was deposited onto a silica glass substrate using the Langmuir–Blodgett film technique. NbO x nanocrystals were prepared via proton-exchange and exfoliation processes of highly crystalline, layered K 4 Nb 6 O 17 crystals obtained by flux-growth. The 3-D crystal layers were fabricated by coating the pastes containing NbO x nanosheets onto the PS microsphere templates, followed by a heating treatment in an electric furnace. During the heating process, the PS microsphere templates were thermally decomposed, and the NbO x nanosheets were transformed into Nb 2 O 5 nanotubes. As a result, transparent/colorless, nano-/micro-textured surfaces were formed on the silica glass substrates. The surface structure clearly varied depending on the nanosheet concentration of the pastes. The rough, solid surfaces modified with fluoroalkylsilane were found to be highly hydrophobic (water contact angle=148°). The 3-D nano-/micro-textures of the Nb 2 O 5 -layered surfaces enhanced their hydrophobicity. The highly hydrophobic surfaces were converted to ultrahydrophilic surfaces by photocatalytic oxidation using Nb 2 O 5 nanotube layers.

Highly crystalline, NaYF4 and NaYF4:Ln (Ln = Yb, Er, Tm) crystals with upconversion fluorescence were successfully grown by the cooling of the solo NaF flux at a holding temperature of 1100 °C and cooling rate of 5 °C·h−1. The basic forms of NaYF4 and NaYF4:Ln crystals were a sphere. The crystal system, form, and size were affected by cooling rate. The red, green, and blue upconversion fluorescence of NaYF4:Ln crystals were clearly observed under 980 nm laser irradiation by a two- or three-photon upconversion process. The upconversion fluorescence of NaYF4:Ln crystals was successfully controlled by changing the cooling rate and type of dopant. Furthermore, the NaYF4:Yb,Er crystals were successfully grown using a mixed NaF-KF flux cooling method at a relatively low temperature of 800 °C.

High quality, idiomorphic hydroxyapatite (HAp) nanocrystals were directly, selectively and successfully grown on the hydrophobic/hydrophilic patterned surface via gel method. The patterned agar gel acted successfully as the micro reaction cell between raw materials. The HAp nanocrystals densely covered the hydrophilic surface, but their shape depended greatly on growth period. After 20 d growth, they were highly crystalline and well developed, and their crystal shape changed to form the one-dimensional (1-D) structure. Furthermore, idiomorphic, hexagonal cylindrical HAp nanocrystals were obtained after annealing at 600 °C for 5 h. It is expected to become considerably important in researching the direct growth/patterning of biocrystals.

Highly crystalline, well-developed potassium titanoniobate (KTiNbO5 and KTi3NbO9) crystals were successfully grown at temperatures ranging from 700 to 1000 °C by a KCl flux cooling method. Colourless and transparent KTiNbO5 crystals with a smallest average size of 750 nm were grown at a relatively low temperature of 700 °C. The sizes of grown crystals were observed to greatly dependent on the holding temperature and solute concentration. HRTEM observations indicated that the flux-grown KTiNbO5 crystals were of high quality. The band gap energies of the fabricated KTiNbO5 and KTi3NbO9 crystals, as estimated from their absorption edges in UV-vis diffuse reflectance spectra, were approximately 3.54 and 3.35 eV, respectively. Furthermore, these crystals exhibited good photocatalytic activities under UV light irradiation. The photodecomposition of TCE gas occurred via a photocatalytic process under UV light irradiation. This study demonstrates that KCl flux cooling is an environmentally friendly and nature-mimetic process for growing high-quality, well-developed, and photocatalytic KTiNbO5 and KTi3NbO9 crystals.

High quality LiCoO2 crystals, useful as cathode material for lithium-ion rechargeable batteries, were successfully grown at a holding temperature of 800−1000 °C using the NaCl flux cooling method. The morphology, structure, size uniformity, and crystallinity of the obtained LiCoO2 crystals were obviously dependent on the growth conditions, such as the holding temperature and the starting composition. Well-developed, highly crystalline LiCoO2 crystals were first grown at a holding temperature of 900 °C from a NaCl flux. The grown LiCoO2 crystals had a hexagonal barrel-shaped structure with well-developed {001}, {104}, {101}, and {102} faces. On the basis of the powder X-ray diffraction data, the lattice parameters of the crystals were determined as a = 2.816 and c = 14.077 A. These values agree approximately with those from the literature (a = 2.816 and c = 14.052 A). The average crystal size was about 1.4 μm, which is a relatively small size when compared to previous reports. Transmission electron microsc...

Highly crystalline and oriented Na2Ti3O7 whiskers were successfully and directly grown on a metallic titanium mesh using a NaCl flux cooling method for application to semiconducting photocatalysis. Specifically, unique three-dimensional photocatalytic materials were fabricated by converting a titanium mesh into a Na2Ti3O7 tubular mesh consisting of highly oriented whiskers. The formation mechanism of the oriented Na2Ti3O7 whiskers was investigated using field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray diffraction. From these results, the following conclusions could be confirmed. First, a titanium oxide layer was formed on the Ti wire surface by thermal oxidation. Since this oxide layer acts as a protective layer to thermal energy, the wire shape was maintained during Na2Ti3O7 whisker growth. Next, highly oriented Na2Ti3O7 whiskers were directly grown on the titanium oxide layer. During whisker growth, Ti was radially supplied from the bulk of the Ti mesh to the ...

Highly crystalline upconversion fluorescence crystals of ytterbium phosphate (YbPO4) doped with Er3+ or Tm3+ were selectively and directly grown on a hydrophilic/hydrophobic self-assembled monolaye...

Activated carbon surfaces were modified using molten KNO3 to introduce functional groups and form microtextures. Their surface treatment temperatures were 250—300 °C; the melting point of KNO3 is 337 °C. Microtextures formed on the surfaces of the activated carbons during the molten KNO3 treatment. Furthermore, various functional groups such as -COOH, -COO, and -CO, were observed clearly in XPS spectra of the surface-modified activated carbons. Their metal-ion adsorption ability increased in the order of activated carbon modified at 300 °C > activated carbon modified at 250 °C > original activated carbon.

YbPO4:Er nanocrystals with upconversion fluorescence were successfully prepared using a two-step process, i.e., gelatin gel growth of YbPO4:Er·nH2O precursors and subsequent annealing. The YbPO4:Er·nH2O precursors grown in gelatin gels were milky white, spherical in shape and uniform in size and appearance. The spherical YbPO4:Er·nH2O precursors were an aggregation of numerous, dense nanospheres (10−50 nm). The average diameters were dependent on growth conditions, such as growth period and concentrations of gel and inner and outer solutions. After the precursor spheres were annealed, their shapes changed dramatically to an aggregation of YbPO4:Er nanocubes (50−300 nm) in three dimensions (900 °C) and large and well-formed crystals (∼500 nm) of YbPO4:Er (1100 °C). The prepared YbPO4:Er crystals showed a bright green upconversion emission under 980 nm laser irradiation by a two-photon upconversion process.

The effects of coated materials for Si probes on the sizes of line structure by using anodization scanning probe lithography (SPL) are investigated by using atomic force microscopy (AFM). Anodization SPL was carried out on the 1-decane monolayer directly attached to hydrogen-terminated silicon. Gold-coated, diamond-coated, and uncoated Si probes were used as the SPL probes in order to fabricate line structures of silicon oxide. In the cases of Au-coated and uncoated Si probes, the widths of line structures are widely influenced by the changes of scanning rate and applied bias voltage. However, the line width fabricated by use of the diamond-coated probe maintained 15 nm under any condition of scanning rate and applied bias voltage. One of the most narrow and three-dimensional nanostructures is found to be successfully fabricated on the hydrogen-terminated Si substrates when the diamond-coated probe was used as a probe of anodization SPL. In addition, this result indicated that high reproducibility of oxide nanostructures is attainable by anodization SPL used the diamond-coated probe.

The binary alkyl- and amino-terminated self-assembled monolayers (SAMs) composed of nano/micro-sized domains was prepared though a self-assembly technique. In addition, the wetting and electrostatic property of the binary SAMs was investigated by the analysis of the static and dynamic water contact angle and zeta-potentials measurement. The binary SAMs were also characterized by atomic force microscope (AFM), Kelvin probe force microscope (KPFM) and X-ray photoelectron spectroscopy (XPS). The domains on the binary SAMs were observed in topographic and surface potential images. The height of domain and the surface potential between octadecyltrichlorosilanes (OTS)-domain and n-(6-aminohexl)aminopropyl-trimethoxysilane (AHAPS)-SAM were about 1.1 nm and −30 mV. These differences of height and surface potential correspond to the ones between OTS and AHAPS. In XPS N 1s spectra, we confirmed the formation of binary SAMs by an amino peak observed at 399.15 eV. The dynamic and the static water contact angles indicated that the wetting property of the binary SAMs was depended on the OTS domain size. In addition, static water contact angles were measured under the conditions of different pH water and zeta-potential also indicated that the electrostatic property of the binary SAMs depended on OTS domain size. Thus, these results showed that the wetting and electrostatic property on the binary SAMs could be regulated by controlling the domain size.

The effect of reaction temperature on the self-organization and growth mechanism of octadecyltrichlorosilane (OTS) self-assembled monolayers (SAM) was investigated by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXD) measurement, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). OTS SAM was prepared by a liquid phase method and chemical vapor deposition. In the liquid phase method, OTS SAM was prepared in the temperature range from 5 to 40 °C. In the reaction temperature range from 5 to 30 °C, OTS molecules formed domain structures early in the growth process and grew two-dimensionally on SiO2 substrates. In addition, the crystalline peaks of GIXD measurements indicated that OTS SAM prepared at lower temperatures (5–30 °C) grew in the crystalline state. Thus, "self-organization" occurred under these conditions. However, OTS SAM prepared at 40 °C showed an amorphous structure. XPS and FT-IR spectra showed that the SiO2 peak increased while reaction temperature decreased. These results indicated that the formation of a siloxane bond between OTS molecules was important for the self-organization of the OTS monolayer. In addition, FT-IR measurement indicated that the packing density of the OTS monolayer prepared at lower temperatures was higher than that prepared at higher temperatures by chemical vapor deposition.

The effect of humidity on the self-organization and growth mechanism of octadecyltrichlorosilane (OTS) monolayers was investigated using an atomic force microscope (AFM), grazing incidence X-ray diffraction (GIXD), and Fourier transform IR spectroscopy (FT-IR). OTS self-assembled monolayers (SAMs) were prepared under humidity ranging from 5 to 80%. Under humidity ranging from 15 to 80%, OTS molecules produced domain structures early in the growth process that grew two-dimensionally on SiO2 substrates. Also, the crystalline peaks of the obtained from the GIXD measurement indicated that OTS-SAMs prepared under high humidity (15–80%) had grown in a crystalline state. Thus, "self-organization" occurred under these conditions. However, OTS-SAMs prepared under 5% humidity were in an amorphous structure. OTS-SAMs prepared at high humidity were denser than those prepared at low humidity. The domain size early in the growth process increased in proportion to the solution age. This shows that the reaction rate is governed by the hydrolysis of organosilane. On the other hand, solution age has no great influence on the density of the OTS-SAMs under conditions of more than 50% humidity.