In Situ Observation and Phase-Field Simulation Framework of Duplex Stainless-Steel Slab during Solidification.

The melting and solidification process of S32101 duplex stainless steel (DSS) was investigated using high-temperature confocal microscopy (HTCM). The method of concentric HTCM was employed to study microstructure evolution during the solidification process of S32101 DSS. This method could artificially create a meniscus-shaped solid-liquid interface, which dramatically improved the quality of in situ observations. During the heating stage, γ-austenite transformed to δ-ferrite, and this transformation manifested itself in the form of grain boundaries (GBs) moving. The effects of cooling rate on the solidification pattern and microstructure were revealed in the present research. An enhanced cooling rate led to a finer microstructure, and the solidification pattern changed from cellular to dendritic growth. As the temperature decreased, the commencement and growth of precipitates were observed. In this paper, the experimental data, including parameters such as temperature, cooling rate, and growth mode, were used as the benchmark for the simulation. A simulation framework using Micress linked to a 1D heat transfer model enabling consistent analysis of solidification dynamics in DSS across the whole cast slab was established. Simulating the dendrite growth and elemental segregation of DSS at specific cooling rates shows that this framework can be a powerful tool for solving practical production problems.

Clinical and Analytical Validation of a Novel Urine-Based Test for the Detection of Allograft Rejection in Renal Transplant Patients.

In this clinical validation study, we developed and validated a urinary Q-Score generated from the quantitative test QSant, formerly known as QiSant, for the detection of biopsy-confirmed acute rejection in kidney transplants. Using a cohort of 223 distinct urine samples collected from three independent sites and from both adult and pediatric renal transplant patients, we examined the diagnostic utility of the urinary Q-Score for detection of acute rejection in renal allografts. Statistical models based upon the measurements of the six QSant biomarkers (cell-free DNA, methylated-cell-free DNA, clusterin, CXCL10, creatinine, and total protein) generated a renal transplant Q-Score that reliably differentiated stable allografts from acute rejections in both adult and pediatric renal transplant patients. The composite Q-Score was able to detect both T cell-mediated rejection and antibody-mediated rejection patients and differentiate them from stable non-rejecting patients with a receiver-operator characteristic curve area under the curve of 99.8% and an accuracy of 98.2%. Q-Scores < 32 indicated the absence of active rejection and Q-Scores ≥ 32 indicated an increased risk of active rejection. At the Q-Score cutoff of 32, the overall sensitivity was 95.8% and specificity was 99.3%. At a prevalence of 25%, positive and negative predictive values for active rejection were 98.0% and 98.6%, respectively. The Q-Score also detected subclinical rejection in patients without an elevated serum creatinine level but identified by a protocol biopsy. This study confirms that QSant is an accurate and quantitative measurement suitable for routine monitoring of renal allograft status.

N-doped crumpled graphene derived from vapor phase deposition of PPy on graphene aerogel as an efficient oxygen reduction reaction electrocatalyst.

Nitrogen-doped crumpled graphene (NCG) is successfully synthesized via vapor phase deposition of polypyrrole onto graphene aerogel followed by thermal treatment. The NCG was explored as an electrocatalyst for the oxygen reduction reaction, showing comparable electrocatalytic performance with the commercial Pt/C in alkaline membrane exchange fuel cells because of the well-regulated nitrogen doping and the robust micro-3D crumpled porous nanostructure.

Novel germanium/polypyrrole composite for high power lithium-ion batteries.

Nano-Germanium/polypyrrole composite has been synthesized by chemical reduction method in aqueous solution. The Ge nanoparticles were directly coated on the surface of the polypyrrole. The morphology and structural properties of samples were determined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Thermogravimetric analysis was carried out to determine the polypyrrole content. The electrochemical properties of the samples have been investigated and their suitability as anode materials for the lithium-ion battery was examined. The discharge capacity of the Ge nanoparticles calculated in the Ge-polypyrrole composite is 1014 mAh g(-1) after 50 cycles at 0.2 C rate, which is much higher than that of pristine germanium (439 mAh g(-1)). The composite also demonstrates high specific discharge capacities at different current rates (1318, 1032, 661, and 460 mAh g(-1) at 0.5, 1.0, 2.0, and 4.0 C, respectively). The superior electrochemical performance of Ge-polypyrrole composite could be attributed to the polypyrrole core, which provides an efficient transport pathway for electrons. SEM images of the electrodes have demonstrated that polypyrrole can also act as a conductive binder and alleviate the pulverization of electrode caused by the huge volume changes of the nanosized germanium particles during Li(+) intercalation/de-intercalation.

Tin/polypyrrole composite anode using sodium carboxymethyl cellulose binder for lithium-ion batteries.

A tin nanoparticle/polypyrrole (nano-Sn/PPy) composite was prepared by chemically reducing and coating Sn nanoparticles onto the PPy surface. The composite shows a much higher surface area than the pure nano-Sn reference sample, due to the porous higher surface area of PPy and the much smaller size of Sn in the nano-Sn/PPy composite than in the pure tin nanoparticle sample. Poly(vinylidene fluoride) (PVDF) and sodium carboxymethyl cellulose (CMC) were also used as binders, and the electrochemical performance was investigated. The electrochemical results show that both the capacity retention and the rate capability are in the same order of nano-Sn/PPy-CMC > nano-Sn/PPy-PVDF > nano-Sn-CMC > nano-Sn-PVDF. Scanning electronic microscopy (SEM) and electrochemical impedance spectroscopy (EIS) results show that CMC can prevent the formation of cracks in electrodes caused by the big volume changes during the charge-discharge process, and the PPy in the composite can provide a conducting matrix and alleviate the agglomeration of Sn nanoparticles. The present results indicate that the nano-Sn/PPy composite could be suitable for the next generation of anode materials with relatively good capacity retention and rate capability.

Room-temperature solution synthesis of Bi2O3 nanowires for gas sensing application.

A simple room-temperature solution chemical route for bulk synthesis of high quality alpha-Bi(2)O(3) nanowires has been demonstrated. The nanowires have a diameter of about 50 nm and a length in the range of several to tens of micrometers. It was found that oleic acid played an important role in directing the growth of alpha- Bi(2)O(3) nanowires along the [102] direction, and the diameter of the nanowires increased with an increase of the reaction temperature. Furthermore, the Bi(2)O(3) nanowire sensors are highly sensitive to ppm-levels of NO(2) in ambient air with fast response, good selectivity and stability, indicating their potential applications for environmental monitoring and pollution control.

Flutelike porous hematite nanorods and branched nanostructures: synthesis, characterisation and application for gas-sensing.

Flute-like porous alpha-Fe2O3 nanorods and branched nanostructures such as pentapods and hexapods were prepared through dehydration and recrystallisation of hydrothermally synthesised beta-FeOOH precursor. Transmission electron microscopy (TEM), high-resolution TEM and selected area electron diffraction analyses reveal that the nanorods, which grow along the [110] direction, have nearly hollow cavities and porous walls with a pore size of 20-50 nm. The hexapods have six symmetric arms with a diameter of 60-80 nm and length of 400-900 nm. The growth direction of the arms in the hexapod-like nanostructure is also along the [110] direction, and there is a dihedral angle of 69.5 degrees between adjacent arms. These unique iron oxide nanostructures offer the first opportunity to investigate their magnetic and gas sensing properties. The nanostructures exhibited unusual magnetic behaviour, with two different Morin temperatures under field-cooled and zero-field-cooled conditions, owing to their shape anisotropy and magnetocrystalline anisotropy. Furthermore, the alpha-Fe2O3 nanostructures show much better sensing performance towards ethanol than that of the previously reported polycrystalline nanotubes. In addition, the alpha-Fe2O3 nanostructure based sensor can selectively detect formaldehyde and acetic acid among other toxic, corrosive and irritant vapours at a low working temperature with rapid response, high sensitivity and good stability.

Histology of the nasal septal swell body (septal turbinate).

OBJECTIVE: To analyze the vascular and glandular elements of the nasal septal swell body (NSB) and quantitatively compare these to the inferior turbinate (IT) and non-swell body portion of septum. STUDY DESIGN: Fourteen healthy adults undergoing septoplasty and IT reduction were submitted to unilateral biopsies of the NSB, the adjacent inferior turbinate, and inferior septum. Photomicrography with morphometric analysis was used to determine the relative area proportions of each tissue type. RESULTS: NSB was rich in seromucinous glands (49.9% +/- 7.0%) compared to IT (19.9% +/- 5.5%), P < 0.01. Conversely, IT mucosa demonstrated increased area proportion of venous sinusoids (28.3 +/- 13.9) compared to NSB (10.0 +/- 6.0), P < 0.01. Inferior septal mucosa had glandular and vascular elements similar in proportion to that of NSB. CONCLUSIONS AND SIGNIFICANCE: NSB is a highly glandular structure of the anterior-superior septum, with moderate proportion of venous sinusoids. Located at the distal valve segment, the NSB appears structured for secretory function and vasoactive airflow regulation.

Aerodynamic effects of inferior turbinate reduction: computational fluid dynamics simulation.

OBJECTIVE: To investigate the aerodynamic consequences of conservative unilateral inferior turbinate reduction using computational fluid dynamics methods to accomplish detailed nasal airflow simulations. DESIGN: A high-resolution, finite-element mesh of the nasal airway was constructed from magnetic resonance imaging data of a healthy man. Steady-state, inspiratory airflow simulations were conducted at 15 L/min using the techniques of computational fluid dynamics. INTERVENTION: Circumferential removal of 2 mm of soft tissue bulk along the length of the left inferior turbinate was modeled. MAIN OUTCOME MEASURES: Nasal airflow distribution and pressure profiles were computed before and after simulated left inferior turbinate reduction. RESULTS: Simulated inferior turbinate reduction resulted in a broad reduction of pressure along the nasal airway, including the regions distant from the inferior turbinate vicinity. In contrast, relative airflow changes were regional: airflow was minimally affected in the valve region, increased in the lower portion of the middle and posterior nose, and decreased dorsally. CONCLUSION: Use of computational fluid dynamics methods should help elucidate the aerodynamic significance of specific surgical interventions and refine surgical approaches to the nasal airway.

Partial inferior turbinectomy using the microdébrider.

BACKGROUND: A microdébrider was selected to accomplish partial inferior turbinectomy, allowing for controlled and rapid removal of hypertrophic soft tissue while preserving the general turbinate form. OBJECTIVE: To assess the clinical outcome, healing, and any adverse consequences from the microdébrider partial turbinectomy procedure. SETTING: A public hospital in north-central Israel. DESIGN: A nonrandomized prospective study of 35 adults who were referred for nasal airway surgery, including turbinectomy. METHODS: All patients underwent bilateral inferior turbinate reduction with the microdébrider, with removal of mucosa from the medial and inferior portions of the inferior turbinates. Detailed follow-up was accomplished at 4 or more months postoperatively, including a visual analogue scale questionnaire and videoendoscopy. For seven patients, pre- and postoperative mucosal biopsies were available to evaluate healing and epithelial regeneration. RESULTS: Nasal endoscopy showed well-healed turbinate membranes and preservation of the turbinate form, with widening of the inferomedial nasal airway space. Subjective nasal patency improved after surgery, p < .01, and the subjective sense of smell was improved, p < .01, without associated crusting, pain, irritation, sneezing, or dryness. Postoperative biopsies showed subepithelial fibrosis and regenerated epithelium, generally of respiratory differentiation. CONCLUSION: Inferior turbinate reduction can be accomplished efficiently with the microdébrider device, without undue side effects. SIGNIFICANCE: Further experience and long-term follow-up with this technique are warranted.

Endoscopic partial adenoidectomy for children with submucous cleft palate.

OBJECTIVE: Children with submucous cleft palate who suffer from chronic nasal obstruction because of hypertrophic adenoids usually are not subjected to adenoidectomy because of the fear of postoperative velopharyngeal insufficiency. These patients present a therapeutic challenge because we are aware more than ever of the importance of normal nasal breathing and nocturnal respiration, especially during childhood. Our hypothesis was that transnasal endoscopic horizontal limited adenoidectomy may relieve nasal obstruction while preserving the function of the velopharyngeal valve. The objective of this study was to evaluate the efficacy of transnasal endoscopic horizontal partial adenoidectomy in patients with submucous cleft palate and adenoidal hypertrophy. SETTING: Patients were either referred to the outpatient clinic of the Palate Surgery Unit (seven patients) or were patients referred to the senior author's (Y.F.) private clinic. All the patients had been operated on by this senior author (Y.F.). PATIENTS: Ten children aged 3.5 to 13 years (six girls and four boys) with submucous cleft palate and hypertrophic adenoids were included in the study. All the patients were hyponasal and suffered nasal obstruction, loud snoring, and episodes of apnea. INTERVENTIONS: Endoscopic partial adenoidectomy was accomplished to open the lower third of the choanae. Nasal breathing was achieved in all the patients, and only mild snoring remained in two patients. The hyponasality disappeared and speech intelligibility normalized. Mild hypernasality developed in two patients but was still perceived as an overall improvement in speech. CONCLUSIONS: Transnasal endoscopic horizontal partial adenoidectomy may be an effective surgical method for relief of nasal obstruction while preserving velopharyngeal valve function in patients with submucous cleft palate who suffer from obstructive adenoids.