WO3-ZnO and CuO-ZnO nanocomposites as highly efficient photoanodes under visible light illumination.

We prepared ZnO nanocomposites with WO3 or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. Characterization of the nanocomposites using scanning electron microscopy, x-ray diffraction, UV-vis spectrometry and photoluminescence revealed the morphologies and wide light absorption range of the materials. The highest current densities of WO3/ZnO and CuO/ZnO nanocomposites were 1.28 mA cm-2 and 2.49 mA cm-2 at 1.23 V (versus a reversible hydrogen electrode) under AM 1.5 100 mW cm-2, which are ~1.2- and 3.5-fold greater than those of bare ZnO nanostructures, respectively. The easy fabrication process suggests that nanocomposites with narrow bandgap materials, such as WO3 and CuO, will improve the performance of electrochemical and optoelectrical devices such as dye-sensitized solar cells and biosensors.

Survivorship Analysis and Clinical Outcomes of Transtibial Pullout Repair for Medial Meniscus Posterior Root Tears: A 5- to 10-Year Follow-up Study.

PURPOSE: This study investigated the clinical outcomes and mid- to long-term survival rates in patients undergoing transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) after a minimum follow-up of 5 years. METHODS: Between 2005 and 2011, patients with MMPRTs who had been followed for at least 5 years after undergoing transtibial pullout repair were recruited. Participants were identified using medical records and information in a prospectively collected database. Clinical outcomes were assessed based on a comparison of patient preoperative Lysholm scores and their scores at the final follow-up. A Kaplan-Meier survival analysis was used to investigate the survival rates of repair procedures. Clinical failures were defined as cases requiring conversion to total knee arthroplasty (TKA) or having final Lysholm score <65 or less than their preoperative scores. RESULTS: Overall, 91 patients (mean age, 58.7 ± 9.7 years) were included: the mean follow-up duration was 84.8 ± 13.8 months. Among these patients, the mean Lysholm score improved significantly from 51.8 ± 7.9 preoperatively to 83.0 ± 11.1 at the final follow-up (P < .001). Overall, 4 patients failed due to conversion to TKA (n = 1) or having final Lysholm scores <65 or less than the preoperative scores (n = 3). The overall Kaplan-Meier probabilities of survival after repair were 99% at 5 years, 98% at 6 years, 95% at 7 years, and 92% at 8 years. CONCLUSIONS: Among patients with MMPRTs, transtibial pullout repair demonstrated a high clinical survival rate and the patients demonstrated clinical improvement, based on mid- and long-term follow-up examinations. LEVEL OF EVIDENCE: Level IV, retrospective uncontrolled case series.

Cross-comparisons of trending accuracies of continuous cardiac-output measurements: pulse contour analysis, bioreactance, and pulmonary-artery catheter.

We compared the similarity of cardiac-output (CO) estimates between available bolus thermodilution pulmonary-artery catheters (PAC), arterial pulse-contour analysis (LiDCOplus™, FloTrac™ and PiCCOplus™), and bioreactance (NICOM™). Repetitive simultaneous estimates of CO obtained from the above devices were compared in 21 cardiac-surgery patients during the first 2 h post-surgery. Mean and absolute values for CO across the devices were compared by ANOVA, Bland-Altman, Pearson moment, and linear-regression analyses. Twenty-one simultaneous CO measurements were made before and after therapeutic interventions. Mean PAC CO (5.7 ± 1.5 L min) was similar to LiDCO™, FloTrac™, PiCCO™, and NICOM™ CO (6.0 ± 1.9, 5.9 ± 1.0, 5.7 ± 1.8, 5.3 ± 1.0 L min, respectively). Mean CO bias between each paired method was -0.10 (PAC-LiDCO), 0.18 (PAC-PiCCO), -0.40 (PAC-FloTrac), -0.71 (PAC-NICOM), 0.28 (LiDCO-PiCCO), 0.39 (LiDCO-FloTrac), -0.97 (NICOM-LiDCO), 0.61 (PiCCO-FloTrac), -1.0 (NICOM-FloTrac), -0.73 (NICOM-PiCCO) L/min, with limits of agreement (1.96 SD, ±95% CI) of ± 2.01, ±2.35, ±2.27, ±2.70, ±1.97, ±2.17, ±3.51, ±2.87, ±2.40, and ± 3.14 L min, respectively, and the percentage error for each of the paired devices was 35, 41, 40, 47, 33, 36, 59, 50, 42, and 55%, respectively. From Pearson moment analysis, dynamic changes in CO, estimated by each device, showed good cross-correlations. Although all devices studied recorded similar mean CO values, which dynamically changed in similar directions, they have markedly different bias and precision values relative to each other. Thus, results from prior studies that have used one device to estimate CO cannot be used to validate others devices.

Obese children experience more extremity fractures than nonobese children and are significantly more likely to die from traumatic injuries.

UNLABELLED: Two of the most prevalent problems children facing worldwide are injuries and obesity. We conducted a systematic review of published studies that evaluated the effects of obesity on children with traumatic injuries. Six studies published between 2006 and 2014 were identified, comprising a total of 4594 children: 867 were obese and 3727 were not. Obese children were 25% more likely to have extremity fractures than nonobese children (p = 0.003), and their mortality rate was significantly higher at 4.7% versus 2.8% (p = 0.026). CONCLUSION: Our review showed that obese children were more likely to have extremity fractures and die of traumatic injuries than nonobese children.

Differential Effects of Left Ventricular Pacing Sites on Regional Contraction Patterns and Global Performance.

OBJECTIVE: To define the differential effect of site-specific ventricular counterpacing efficacy during cardiac resynchronization therapy (CRT) to identify the most informative imaging views to quantify it. Cross-sectional and long-axis views commonly are used to assess left ventricular (LV) contractility. DESIGN: The effects of LV apical (LVa) and free-wall (LVfw) pacing during CRT on long- and short-axis contraction, cardiac output, and stroke work were assessed in an open-chested acute canine model to determine whether LVa and LVfw would induce earlier apical than basilar LV radial contraction and earlier free-wall than septal contraction, respectively. Apical (CRTa) and free-wall (CRTfw) using right ventricular (RV) pacing-induced dyssynchrony also were examined. SETTING: University large animal research laboratory. PARTICIPANTS: Ten acutely anesthetized and instrumented open-chested purpose-bred dogs. INTERVENTIONS: RV pacing served as the model of cardiac dyssynchrony. Selective LVfw and LVa pacing alone or with RV (CRTfw and CRTa, respectively) were studied relative to right atrial pacing (RA) as the control. MEASUREMENTS AND MAIN RESULTS: Two pairs of 3 ultrasonic crystals were place along the LV longitudinal axis-apex and mid-to-base pairs along septal and free wall lines. Conductance catheter-defined longitudinal LV segmental volumes and pressure-volume data were collected. RV decreased cardiac output and stroke work compared with RA (2.0±0.3 v 1.4±0.1 L/min; 137±22 v 60±14 mJ; p<0.05, respectively). LVfw but not LVa decreased stroke work (130±35 mJ), and CRTa but not CRTfw improved both (2.1±0.2 L/min; 113±13 mJ; p<0.01 v RV pacing). No difference in time to minimal length free wall-to-septal crystal was seen with pacing. Both LVa and CRTa displayed increased apical-to-basilar shortening delay compared with RA, RV, and LVfw (42±47, 9±105, and 1±46 msec, respectively; p<0.05). No matching regional LV volume changes were seen during LVa. CONCLUSIONS: LV functional analysis from only a cross-sectional plane may be insufficient to characterize improved LV contraction synchrony during multisite CRT.

Probing the interaction of caffeic acid with ZnO nanoparticles.

The binding of ZnO nanoparticles (NPs) and caffeic acid (CFA) was investigated using fluorescence quenching, UV/vis absorption spectrscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) at different temperatures. The study results indicated fluorescence quenching between ZnO NPs and CFA rationalized in terms of a static quenching mechanism or the formation of non-fluorescent CFA-ZnO. From fluorescence quenching spectral analysis, the binding constant (K(a)), number of binding sites (n) and thermodynamic properties were determined. Values of the quenching (K(SV)) and binding (K(a)) constants decrease with increasing temperature and the number of binding sites n = 2. The thermodynamic parameters determined using Van't Hoff equation indicated that binding occurs spontaneously involving the hydrogen bond, and van der Waal's forces played a major role in the reaction of ZnO NPs with CFA. The FTIR, TEM and DLS measurements also indicated differences in the structure, morphology and size of CFA, ZnO NPs and their corresponding CFA-ZnO.

Binding of caffeine with caffeic acid and chlorogenic acid using fluorescence quenching, UV/vis and FTIR spectroscopic techniques.

The interactions of caffeine (CF) with chlorogenic acid (CGA) and caffeic acid (CFA) were investigated by fluorescence quenching, UV/vis and Fourier transform infrared (FTIR) spectroscopic techniques. The results of the study indicated that the fluorescence quenching between caffeine and hydroxycinnamic acids could be rationalized in terms of static quenching or the formation of non-fluorescent CF-CFA and CF-CGA complexes. From fluorescence quenching spectral analysis, the quenching constant (KSV), quenching rate constant (kq), number of binding sites (n), thermodynamic properties and conformational changes of the interaction were determined. The quenching constants (KSV) between CF and CGA, CFA are 1.84 × 10(4) and 1.04 × 10(4) L/mol at 298 K and their binding site n is ~ 1. Thermodynamic parameters determined using the Van't Hoff equation indicated that hydrogen bonds and van der Waal's forces have a major role in the reaction of caffeine with caffeic acid and chlorogenic acid. The 3D fluorescence, UV/vis and FTIR spectra also showed that the binding of CF with CFA and CGA induces conformational changes in CFA and CGA.

Effects of solvent polarity on the absorption and fluorescence spectra of chlorogenic acid and caffeic acid compounds: determination of the dipole moments.

The effects of solvent polarity on absorption and fluorescence spectra of biologically active compounds (chlorogenic acid (CGA) and caffeic acids (CA)) have been investigated. In both spectra pronounced solvatochromic effects were observed with shift of emission peaks larger than the corresponding UV-vis electronic absorption spectra. From solvatochromic theory the ground and excited-state dipole moments were determined experimentally and theoretically. The differences between the excited and ground state dipole moment determined by Bakhshiev, Kawski-Chamma-Viallet and Reichardt equations are quite similar. The ground and excited-state dipole moments were determined by theoretical quantum chemical calculation using density function theory (DFT) method (Gaussian 09) and were also similar to the experimental results. The HOMO-LUMO energy band gaps for CGA and CFA were calculated and found to be 4.1119 and 1.8732 eV respectively. The results also indicated the CGA molecule is more stable than that of CFA. It was also observed that in both compounds the excited state possesses a higher dipole moment than that of the ground state. This confirms that the excited state of the hydroxycinnamic compounds is more polarized than that of the ground state and therefore is more sensitive to the solvent.

Is magnetic resonance imaging necessary in isolated greater trochanter fracture? A systemic review and pooled analysis.

BACKGROUND: Isolated fractures of the greater trochanter (GT) of the femur are uncommon and few studies have assessed the diagnosis and appropriate therapeutic schedule for these fractures. The current data regarding assessment of isolated fractures of the GT are limited to a few reviews based on the experience of a single institution. Therefore, we asked the following questions: (1) what proportion of cases has an associated extension of the fracture into the intertrochanteric region in isolated GT fracture and (2) what are the treatment options and outcomes of GT fractures with occult intertrochanteric fractures. METHODS: We conducted a systematic review of published studies that evaluated patients who displayed isolated GT fracture on routine radiographic examination and underwent a magnetic resonance imaging (MRI) scan because of the suspicion of extension into the intertrochanteric region. A structured literature review of multiple databases (PubMed, EMBASE, CINAHL, and Cochrane systematic reviews) referenced articles from 1950 to 2015. RESULTS: A total of 110 patients were identified from 7 published studies. MRI documented isolated GT fractures diagnosed on initial radiographs in only 11 of 110 patients (10%). In 99 patients (90%), MRI examinations revealed extension of the fracture into the intertrochanteric region. Surgical fixation was necessary for 61 patients, with a pooled percentage of 55%. No complications were observed after surgery. CONCLUSIONS: Our study has helped to elucidate further the assessment of isolated fracture of the GT. We believe that MRI is a reasonable option for patients presenting with isolated GT fracture on plain radiographs.

Mesoporous silica with fibrous morphology: a multifunctional core-shell platform for biomedical applications.

Multifunctional mesoporous silica nanocomposites are attractive carriers for targeted drug delivery in nanomedicine. Although promising developments have been made in the fabrication of multifunctional mesoporous silica nanocomposites, the design and mass production of novel multifunctional carriers are still challenging. This paper reports the facile one-pot fabrication of a multifunctional inorganic composite composed of superparamagnetic Fe3O4 nanoparticles and coated dye-functionalized mesoporous silica with a high specific surface area. The resulting composite particles had a tunable particle size, special open pore channels with high specific surface area, which is quite favorable for drug loading and release properties, as well as luminescent and superparamagnetic properties suitable for targeted drug delivery and tracking. This composite exhibited low toxicity, suggesting potential biomedical applications.

Robust model-based quantification of global ventricular torsion from spatially sparse three-dimensional time series data by orthogonal distance regression: evaluation in a canine animal model under different pacing regimes.

BACKGROUND: Quantification of global ventricular rotational deformation, expressed as twist or torsion, and its dynamic changes is important in understanding the pathophysiology of heart disease and its therapy. Various techniques, such as sonomicrometry, allow tracking of specific sites within the myocardium. Quantification of twist from such data requires a longitudinal reference axis of rotation. Current methods require specific positioning and numbers of myocardial markers and assumptions about temporal positional evolution that may be violated during dyssynchronous contraction. METHODS: We present a new method to assess myocardial twist that makes minimal fully explicit assumptions while removing extraneous assumptions, by performing a least squares orthogonal distance regression of all position data on an ellipsoidal ventricular model. Rotational deformation is quantified in terms of the ellipsoid's internal coordinate system, allowing intuitive visualization. RESULTS: We tested this method on a set of sparse, noisy sonomicrometric crystal data in dogs under different pacing regimes to model dyssynchrony and cardiac resynchronization. We found that this method yielded robust and plausible data. This technique is also fully automated while identifying when data may be insufficient for reliable quantification of rotational deformation. CONCLUSION: This approach may allow future analysis of myocardial contraction with less tracking sites and relaxed positioning requirements while identifying situations where data are insufficient for reliable quantification of rotational deformation.

Physiologic responses to severe hemorrhagic shock and the genesis of cardiovascular collapse: can irreversibility be anticipated?

BACKGROUND: The causes of cardiovascular collapse (CC) during hemorrhagic shock (HS) are unknown. We hypothesized that vascular tone loss characterizes CC, and that arterial pulse pressure/stroke volume index ratio or vascular tone index (VTI) would identify CC. METHODS: Fourteen Yorkshire-Durock pigs were bled to 30 mmHg mean arterial pressure and held there by repetitive bleeding until rendered unable to compensate (CC) or for 90 min (NoCC). They were then resuscitated in equal parts to shed volume and observed for 2 h. CC was defined as a MAP < 30 mmHg for 10 min or <20 mmHg for 10 s. Study variables were recorded at baseline (B0), 30, 60, 90 min after bleeding and at resuscitation (R0), 30, and 60 min afterward. RESULTS: Swine were bled to 32% ± 9% of total blood volume. Epinephrine (Epi) and VTI were low and did not change in NoCC after bleeding compared with CC swine, in which both increased (0.97 ± 0.22 to 2.57 ± 1.42 mcg/dL, and 173 ± 181 to 939 ± 474 mmHg/mL, respectively), despite no differences in bled volume. Lactate increase rate (LIR) increased with hemorrhage and was higher at R0 for CC, but did not vary in NoCC. VTI identified CC from NoCC and survivors from non-survivors before CC. A large increase in LIR was coincident with VTI decrement before CC occurred. CONCLUSIONS: Vasodilatation immediately prior to CC in severe HS occurs at the same time as an increase in LIR, suggesting loss of tone as the mechanism causing CC, and energy failure as its probable cause.

Advantages of using Ti-mesh type electrodes for flexible dye-sensitized solar cells.

We used Ti meshes for both the photoanodes and counter electrodes of dye-sensitized solar cells (DSSCs) to improve the flexibility and conductivity of the electrodes. These mesh type electrodes showed good transparency and high bendability when subjected to an external force. We demonstrated the advantages of cells using such electrodes compared to traditional transparent conducting oxide based electrodes and back side illuminated DSSCs, such as low sheet resistance, elevated photo-induced current and enhanced sunlight utilization. Nanotube layers of different thicknesses were investigated to determine their effect on the photovoltaic parameters of the cell. The overall efficiency of the best cells was approximately 5.3% under standard air mass 1.5 global (AM 1.5 G) solar conditions. Furthermore, the DSSCs showed an efficiency of approximately 3.15% due to the all Ti-mesh type electrodes even after illumination from the back side.

Physiological relevance of quantifying segmental contraction synchrony.

BACKGROUND: Most current indices of synchrony quantify left ventricular (LV) contraction pattern in terms of a single, global (integrated) measure. We report the development and physiological relevance of a novel method to quantify LV segmental contraction synchrony. METHODS: LV pressure-volume and echocardiographic data were collected in seven anesthetized, opened-chest dogs under several pacing modes: right atrial (RA) (control), right ventricular (RV) (dyssynchrony), and additional LV pacing at either apex (CRTa) or free wall (CRTf). Cross-correlation-based integrated (CCSI(int) ) and segmental (CCSI(seg) ) measures of synchrony were calculated from speckle-tracking derived radial strain, along with a commonly used index (maximum time delay). LV contractility was quantified using either E(es) (ESPVR slope) or ESPVR(area) (defined in the manuscript). RESULTS: RV pacing decreased CCSI(int) at LV base (0.95 ± 0.02 [RA] vs 0.64 ± 0.14 [RV]; P < 0.05) and only CRTa improved it (0.93 ± 0.03; P < 0.05 vs RV). The CCSI(seg) analysis identified anteroseptal and septal segments as being responsible for the low CCSI(int) during RV pacing and inferior segment for poor resynchronization with CRTf. Changes in ESPVR(area) , and not in E(es) , indicated depressed LV contractility with RV pacing, an observation consistent with significantly decreased global LV performance (stroke work [SW]: 252 ± 23 [RA] vs 151 ± 24 [RV] mJ; P < 0.05). Only CRTa improved SW and contractility (SW: 240 ± 19 mJ; ESPVR(area) : 545 ± 175 mmHg•mL; both P < 0.01 vs RV). Only changes in CCSI(seg) and global LV contractility were strongly correlated (R(2) = 0.698, P = 0.005). CONCLUSION: CCSI(seg) provided insights into the changes in LV integrated contraction pattern and a better link to global LV contractility changes.

Synthesis and photoluminescence properties of Ho3+ doped LaAlO3 nanoparticles.

Nanosized particles with different Ho3+ concentrations were synthesized in LaAlO3 lattices using a simple Pechini-type sol-gel method. X-ray diffraction measurements were used to investigate the structural composition and the effects of holmium dopant concentration on LaAlO3:Ho3+ crystal formation. Field-emission scanning-electron microscopy images confirm the formation of approximately spherical particles with an average size about 100 nm. The photoluminescence results yielded optimal holmium ion concentration in LaAlO3 host matrices was about 3% in mol equivalent. The mechanism that are responsible for the photoluminescence emission processes discussed with the help of Ho3+-ion Dieke energy level diagram. Power dependent slope measurements were performed to identify up-conversion photoluminescence process involved in LaAlO3:Ho3+.

Left ventricular systolic torsion correlates global cardiac performance during dyssynchrony and cardiac resynchronization therapy.

Left ventricular (LV) systolic torsion is a primary mechanism contributing to stroke volume (SV). We hypothesized that change in LV torsion parallels changes in global systolic performance during dyssynchrony and cardiac resynchronization therapy (CRT). Seven anesthetized open chest dogs had LV pressure-volume relationship. Apical, basal, and mid-LV cross-sectional echocardiographic images were studied by speckle tracking analysis. Right atrial (RA) pacing served as control. Right ventricular (RV) pacing simulated left bundle branch block. Simultaneous RV-LV free wall and RV-LV apex pacing (CRTfw and CRTa, respectively) modeled CRT. Dyssynchrony was defined as the time difference in peak strain between earliest and latest segments. Torsion was calculated as the maximum difference between the apical and basal rotation. RA pacing had minimal dyssynchrony (52 ± 36 ms). RV pacing induced dyssynchrony (189 ± 61 ms, P < 0.05). CRTa decreased dyssynchrony (46 ± 36 ms, P < 0.05 vs. RV pacing), whereas CRTfw did not (110 ± 96 ms). Torsion during baseline RA was 6.6 ± 3.7°. RV pacing decreased torsion (5.1 ± 3.6°, P < 0.05 vs. control), and reduced SV, stroke work (SW), and dP/dt(max) compared with RA (21 ± 5 vs. 17 ± 5 ml, 252 ± 61 vs. 151 ± 64 mJ, and 2,063 ± 456 vs. 1,603 ± 424 mmHg/s, respectively, P < 0.05). CRTa improved torsion, SV, SW, and dP/dt(max) compared with RV pacing (7.7 ± 4.7°, 23 ± 3 ml, 240 ± 50 mJ, and 1,947 ± 647 mmHg/s, respectively, P < 0.05), whereas CRTfw did not (5.1 ± 3.6°, 18 ± 5 ml, 175 ± 48 mJ, and 1,699 ± 432 mmHg/s, respectively, P < 0.05). LV torsion changes covaried across conditions with SW (y = 0.94x+12.27, r = 0.81, P < 0.0001) and SV (y = 0.66x+0.91, r = 0.81, P < 0.0001). LV dyssynchrony changes did not correlate with SW or SV (r = -0.12, P = 0.61 and r = 0.08, P = 0.73, respectively). Thus, we conclude that LV torsion is primarily altered by dyssynchrony, and CRT that restores LV performance also restores torsion.

Study of dielectric relaxations of anhydrous trehalose and maltose glasses.

We investigated the frequency dependent dielectric relaxation behaviors of anhydrous trehalose and maltose glasses in the temperature range which covers a supercooled and glassy states. In addition to the α-, Johari-Goldstein (JG) ß-, and γ-relaxations in a typical glass forming system, we observed an extra relaxation process between JG ß- and γ-relaxations in the dielectric loss spectra. We found that the unknown extra relaxation is a unique property of disaccharide which might originate from the intramolecular motion of flexible glycosidic bond. We also found that the temperature dependence of the JG ß-relaxation time changes at 0.95T(g) and it might be universal.

Enhanced stokes and anti-stokes photoluminescence emission from LaAlO3:Nd+3 nanosized powder coated with a SiO2 shell layer.

The research on and development of materials in the field of rare-earth-ion doped nanocrystals for downconversion and up-conversion emission has been recognized to hold tremendous potential in the areas of photonic and biophotonic applications. In the present manuscript, the comprehensive results of the investigation of Stokes and anti-Stokes photoluminescence emission from the prepared LaAlO3:Nd+3 nanoparticles synthesized via the Pechini-type sol-gel method are presented and explained. The XRD diffraction peaks of the LaAlO3:Nd+3 nanoparticles can be easily assigned to the cubic-perovskite LaAlO3 structure. The FESEM image confirms the formation of approximately spherical particles within the range of 80 +/- 30 nm. The PL results showed that the LaAlO3 doped with 5% of Nd+3 ions shows the strongest emission. The core-shell structures obviously enhanced the photoluminescence intensity by suppressing the non-radiative emission and surface defects. As they yield the best PL measurement results, the LaAlO3:0.05Nd+3 nanoparticles were coated with a SiO2 shell layer, to enhance the photoluminescence emission. The mechanisms that are responsible for the photoluminescence emission process observed in the samples are discussed herein, with the help of the Nd+3 ion Dieke energy level diagram. Power dependence slope measurements were performed to identify the processes involved in the LaAlO3:Nd+3 up-conversion photoluminescence.

Unusual melting transition of nitrogen physisorbed on carbon nanotube bundles.

The melting transition of nitrogen physisorbed on close-ended single-wall nanotube bundles was investigated using synchrotron X-ray diffraction measurements. The beta-nitrogen solid diffraction peak was observed above the coverage that corresponded to the monolayer and the average size of the nitrogen solid was approximately 30 A. The diffraction peak was surprisingly maintained above the triple point of the bulk nitrogen solid. The crystal structure of N2 changed from cubic N2 (beta-phase) to hexagonal N2 (beta-phase) at 35.61 K. The melting temperature of the nano-scale solid nitrogen in the experiment was between 80 K and 90 K, however, which is about 20 K higher than the melting temperature of normal bulk nitrogen. The observed extraordinary melting behavior of nitrogen might originate from a combination of two factors, i.e., the substrate field effect of the carbon nanotube surface (the interaction between the single walled carbon nanotubes and the adsorbates) and the capillary condensation. If the substrate field effect is especially prominent, the nitrogen molecules that were adsorbed mainly in the groove region would be under 1,100-Torr pressure from the nanotube bundles, compared to the corresponding melting temperature of the bulk beta-nitrogen solid under a high pressure.

Effects of the nano-tubular anodic TiO2 buffer layer on bioactive hydroxyapatite coating.

We studied the effect of nano-tubular anodic TiO2 buffer layers on hydroxyapatite (HA) coating. The pulsed laser deposition (PLD) method was used to deposit HA on a well arranged nano-tubular anodic TiO2 (NT-ATO) buffer layer prepared by an electrochemical anodization technique. The surface morphology and chemical composition of HA coatings were characterized by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and contact angle measurement. We found that crystalline HA coatings show well arranged porous morphologies with a favorable surface wettability. We also found that an anodic nano-tubular TiO2 buffer layer with a relatively short tube length shows a better coating morphology. The deposition process of HA on the nanotubular TiO2 buffer layer was also proposed.