The characteristics of network formation of multiwall carbon nanotubes (MWCNTs) inside ethylene–octene copolymer (EOC) melts under an alternating current (AC) electric field and the resulting ...electrical conductivity improvements are studied by combining dynamic and steady state resistivity measurements. Fine MWCNT dispersion during melt compounding of the samples is accomplished by means of a novel non-specific, non-covalent functionalization method. It is found that the electrified composite films exhibit nanotube assembly into columnar structures parallel to the electric field, accompanied by dramatic increases in electrical conductivity up to eight orders of magnitude. Experimentally acquired resistivity data are used to derive correlations between the characteristic insulator-to-conductor transition times of the composites and process parameters, such as electric field strength (E), polymer viscosity (η) and nanotube volume fraction (ϕ). Finally, a criterion for the selection of (η,E,C) conditions that enable MWCNT assembly under an electric field controlled regime (i.e., minimal Brownian motion-driven aggregation effects) is developed. The correlations presented herein not only provide insights in the MWCNT assembly process, but can also guide the experimental design in future studies on electrified composites or assist in the selection of process parameters in composites manufacturing.
To evaluate the role of sentinel lymph node biopsy (SLNB) for the treatment of melanoma of the extremities.
From April 2007 to August 2013, forty-eight (25 men and 23 women) cases of melanoma of the ...extremities underwent sentinel lymph node biopsy. All the cases had sentinel lymph node biopsy and surgery. Among them 37 cases underwent limb salvage surgery, while 11 cases underwent amputation. Of the cases with limb salvage, 28 cases underwent free skin grafting or local flap grafting reconstruction after wide resection. Of the surgical margin, wide resection was performed in 37 patients, and radical resection was performed in 11 cases. There were 39 cases in stage I or II, and 9 cases in stage III. After the surgery, adjuvant chemotherapy was performed in 9 cases, and adjuvant biotherapy of interferon and interleukin was performed in 26 cases. Except for 2 cases, 46 cases were followed up with a mean follow-up period of 20.1 months (range from 2 to 60 months).
39 (81.3%) cases had negative SLNB, while 9 (18.8
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•Cost-effective amorphous iron oxide–graphene oxide nanocomposite adsorbents.•Arsenic concentration can be reduced efficiently from ∼110 to <0.02ppb.•High maximum adsorption capacity ...of 147mgg−1 for As(III) and 113mgg−1 for As(V).
We report the synthesis of a new range of iron oxide–graphene oxide (GO) nanocomposites having different iron oxide content (36–80wt%) as high-performance adsorbents for arsenic removal. Synthesized by co-precipitation of iron oxide on GO sheets that are prepared by an improved Hummers method, the iron oxide in the nanocomposites is featured primarily in the desirable form of amorphous nanoparticles with an average size of ca. 5nm. This unique amorphous nanoparticle morphology of the iron oxide beneficially endows the nanocomposites with high surface area (up to 341m2g−1 for FeOx–GO-80 having the iron oxide content of 80wt%) and predominant mesopore structures, and consequently increased adsorption sites and enhanced arsenic adsorption capacity. FeOx–GO-80 shows high maximum arsenic adsorption capacity (qmax) of 147 and 113mgg−1 for As(III) and As(V), respectively. These values are the highest among all the iron oxide–GO/reduced GO composite adsorbents reported to date and are also comparable to the best values achieved with various sophisticatedly synthesized iron oxide nanostructures. More strikingly, FeOx–GO-80 is also demonstrated to nearly completely (>99.98%) removes arsenic by reducing the concentration from 118 (for As(III)) or 108 (for As(V)) to <0.02μgL−1, which is far below the limit of 10μgL−1 recommended by the World Health Organization (WHO) for drinking water. The excellent adsorption performance, along with their low cost and convenient synthesis, makes this range of adsorbents highly promising for commercial applications in drinking water purification and wastewater treatment.
Multi-wall carbon nanotubes (MWCNTs) were functionalized with a hyperbranched polyethylene (HBPE) using a non-covalent, non-specific functionalization approach. The adsorption behavior of HBPE on ...MWCNTs was characterized by means of an adsorption isotherm. HBPE adsorption reached a plateau value of 0.3:1.0 (w/w) HBPE:MWCNT, corresponding to a surface coverage of approximately 30%. The functionalized MWCNTs were better dispersed in tetrahydrofuran (THF), forming smaller aggregates compared to their unmodified counterparts. Pristine and HBPE-functionalized MWCNTs were melt compounded with a low-viscosity ethylene–octene copolymer (EOC) matrix. Electrical and rheological percolation thresholds were observed at nanotube loadings of less than 1wt%. Functionalization did not affect significantly the electrical conductivity and rheological properties. The improved dispersion of the functionalized MWCNTs within the EOC matrix resulted in improved ductility over the non-functionalized counterpart. This study demonstrates that this method of functionalization results in partial surface coverage of the nanotubes, therefore providing an efficient means for achieving good nanotube dispersion, without compromising their surface properties.
Background: Our research group has previously reported a noninvasive model that estimates phosphate removal within a 4-h hemodialysis (HD) treatment. The aim of this study was to modify the original ...model and validate the accuracy of the new model of phosphate removal for HD and hemodiafiltration (HDF) treatment. Methods: A total of 109 HD patients from 3 HD centers were enrolled. The actual phosphate removal amount was calculated using the area under the dialysate phosphate concentration time curve. Model modification was executed using second-order multivariable polynomial regression analysis to obtain a new parameter for dialyzer phosphate clearance. Bias, precision, and accuracy were measured in the internal and external validation to determine the performance of the modified model. Results: Mean age of the enrolled patients was 63 ± 12 years, and 67 (61.5%) were male. Phosphate removal was 19.06 ± 8.12 mmol and 17.38 ± 6.75 mmol in 4-h HD and HDF treatments, respectively, with no significant difference. The modified phosphate removal model was expressed as Tpo 4 = 80.3 × C 45 − 0.024 × age + 0.07 × weight + β × clearance − 8.14 (β = 6.231 × 10 −3 × clearance − 1.886 × 10 −5 × clearance 2 – 0.467), where C 45 was the phosphate concentration in the spent dialysate measured at the 45th minute of HD and clearance was the phosphate clearance of the dialyzer. Internal validation indicated that the new model was superior to the original model with a significantly smaller bias and higher accuracy. External validation showed that R 2 , bias, and accuracy were not significantly different than those of internal validation. Conclusions: A new model was generated to quantify phosphate removal by 4-h HD and HDF with a dialyzer surface area of 1.3–1.8 m 2 . This modified model would contribute to the evaluation of phosphate balance and individualized therapy of hyperphosphatemia.
Aim
To investigate the correlation of renal tubular inflammatory and injury markers with renal uric acid excretion in chronic kidney disease (CKD) patients.
Methods
Seventy-three patients with CKD ...were enrolled. Fasting blood and morning urine sample were collected for routine laboratory measurements. At the same time, 24 h of urine was collected for urine biochemistry analyses, and 10 ml was extracted from the 24-h urine sample to further detect renal tubular inflammatory and injury markers, including interleukin-18 (IL-18), interleukin 1β (IL-1β), neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). The patients were divided into three tertile groups according to their 24-h urinary uric acid (24-h UUA) levels (UUA1: 24-h UUA ≤ 393.12 mg; UUA2: 393.12 < 24-h UUA ≤ 515.76 mg; UUA3: 24-h UUA > 515.76 mg). The general clinical and biochemical indexes were compared. Multivariable linear regression models were used to test the association of IL-18/Urinary creatinine concentration (IL-18/CR), IL-1β/CR, NGAL/CR and KIM-1/CR with renal uric acid excretion indicators.
Results
All of tested renal tubular inflammation- and injury-related urinary markers were negatively associated with 24-h UUA and UEUA, and the negative correlation still persisted after adjusting for multiple influencing factors including urinary protein and eGFR. Further group analyses showed that these makers were significantly higher in the UUA1 than in the UUA3 group.
Conclusions
Our findings suggest that markers of urinary interstitial inflammation and injury in CKD patients are significantly correlated with 24-h UUA and Urinary excretion of uric acid (UEUA), and those with high 24-h UUA have lower levels of these markers. Renal uric acid excretion may also reflect the inflammation and injury of renal tubules under certain conditions.
Lithium‐ion batteries are the predominant energy storage devices for portable electronic devices and hold great promise for renewable energies and sustainability. High capacity and long‐life anode ...materials are highly desired for the next‐generation Li‐ion battery with high energy density. Herein, a high‐performance anode electrode constructed with cobalt and zinc sulfides nanocrystals embedded within a nitrogen and sulfur co‐doped porous carbon is successfully designed bimetal‐organic frameworks as the precursor. Benefiting from synergistic effects of bimetal sulfides, the unique rhombohedral dodecahedral nanostructure with rough surface area and N,S‐codoped carbon matrix, such an anode material presents superior initial reversible capacity of 938.2 mA h g−1 with a high‐capacity retention of 65.6% after 100 cycles at 150 mA/g. The effective nanostructure design is expected to open a venue to construct high‐performance materials for energy and environment applications.
High‐performance anode material with hollow dodecahedral porous N,S‐doped Co/Zn@CN is designed and derived from bimetallic‐organic frameworks exhibiting outstanding initial reversible capacity with a high‐capacity retention performance towards Li‐ion batteries applications.
Long-chain-branched isotactic polypropylenes (LCBed PP) were synthesized by copolymerizing propylene with a small amount of nonconjugated α,ω-diene (1,9-decadiene or 1,7-octadiene) using the catalyst ...system of rac-Me2Si(2-MeBenzeInd)2ZrCl2(MBI)/MMAO. In this approach, the LCB structures were introduced by the incorporation of in situ generated macromonomers with pendant 1-octenyl or 1-hexenyl groups during the polymerization. A detailed study on the effects of diene concentration on polymer properties was conducted. Polymer chain microstructures were characterized by 13C NMR, GPCV, and DSC. In the propylene/1,9-decadiene copolymerization, a series of LCBed polymer samples with the long-chain-branch density (LCBD) of up to 0.53 branch structures per 1000 carbons were produced with the diene concentrations of 0.177−3.54 mmol/L at 40 and 25 °C. A diene concentration of 35.4 mmol/L yielded cross-linked polymer gels. In the copolymerization of propylene and 1,7-octadiene, in addition to a small fraction of LCB structures produced, a cyclic seven-member ring structure was observed due to the cycloaddition of 1,7-octadiene. The cyclization significantly decreased the LCBD in the polymers. A small-amplitude oscillatory shear flow measurement was conducted to evaluate the rheological properties of the LCBed polymers. Compared to the linear samples prepared at the same polymerization conditions, the LCBed polymers exhibited enhanced low-frequency complex viscosity, improved shear-thinning, increased dynamic moduli, and reduced phase angle. The samples also showed thermorheological complexity and enhanced activation energy at low frequencies. These particular properties are related to the LCB in the polymers and become more significant with the increase of LCBD. The LCBed polypropylenes were also blended with their counterpart linear samples and demonstrated the improvement of rheological properties.
A one‐pot procedure for the synthesis of hyperbranched polyethylenes tethered with ATRP initiating sites by chain walking ethylene copolymerization with an acrylate‐type ATRP inimer, ...2‐(2‐bromoisobutyryloxy) ethyl acrylate (BIEA) is reported. Because of its ability to incorporate acrylate‐type comonomers and tolerance toward the α‐bromoester group, the chain walking Pd‐diimine catalyst, (ArNC(Me)(Me)CNAr)Pd(CH3)(NCMe)SbF6 (Ar = 2,6‐(iPr)2C6H3), allowed the successful synthesis of a series of hyperbranched copolymers tethered with 2‐bromoisobutyryl groups at different densities. These copolymers may serve as polyfunctional macroinitiators for the ATRP of functional monomers to further synthesize core‐shell structured functionalized copolymers with a hyperbranched polyethylene core grafted with side chains of the functional monomers.
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