Bifunctional polymer binders featured with both strong binding and superior polysulfide trapping properties are highly desired for the fabrication of sulfur cathodes with suppressed polysulfide ...shuttling in Li–S batteries. In this paper, we have explored the potential of a quaternary ammonium cationic polymer, polydiallyldimethylammonium (PDADMA-X; X = T, B, P, and Cl) with different counter anions (TFSI–, BF4−, PF6−, and Cl−, respectively) as the bifunctional binder. We have also revealed the dramatic effects of the counter anion on the performance of the cationic polymer binder. PDADMA-X's containing the former three weakly associating anions have been demonstrated to show polysulfide adsorption capability. In particular, PDADMA-T having the largest, least interacting TFSI– anion shows the optimum performance, with strong binding strength and the best polysulfide adsorption capability. Relative to commercial PVDF and PDADMA-X's of other counter anions, it offers sulfur cathodes with lowered polarization, higher discharge capacity, significantly better capacity retention, and improved cycling stability. With its convenient synthesis from commercially available PDADMA-Cl, cationic PDADMA-T having the TFSI– anion is a promising bifunctioal binder for sulfur cathodes in practical Li-sulfur batteries.
The organic nitroxyl radical, TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl), finds a variety of industrial applications for chemical transformations. Because of economic and environmental concerns, ...the recovery and reuse of TEMPO with maintained high activity are of the utmost importance. In this Review, we summarize the most important advances made by the scientific community in TEMPO immobilization on various organic and inorganic support materials for recovery and reuse, and we discuss the activity and stability, as well as the procedures. Also summarized is the wide range of applications of TEMPO in both homogeneous and heterogeneous forms in chemical transformations, beginning from methodology tuning in synthetic chemistry to the use in polymer chemistry.
Polymer chain architecture is a critically important chain parameter governing intrinsically the properties and applications of polymers. The rapid developments in "living"/controlled polymerization ...techniques, particularly the controlled radical polymerization techniques, in the past two decades have enabled the precision synthesis of novel polymers having a great variety of complex yet well-defined chain architectures from various monomer stocks. For polyolefins synthesized via catalytic coordination polymerization, the design of complex chain architectures, however, has only started recently because of the relatively limited advancements in the catalytic "living" olefin polymerization technique. In this regard, the versatile Pd-diimine catalysts have provided some unprecedented opportunities, due to their outstanding features, in rendering successfully a novel class of polyethylenes of various new complex chain architectures through the "living" ethylene polymerization protocol. The complex chain architectures designed to date have included hyperbranched, hybrid hyperbranched-linear, block, gradient and block-gradient, star, telechelic, graft and comb, and surface-tethered polymer brushes. This Feature Article attempts to summarize the recent developments achieved in the area, with an emphasis on the synthetic strategies for the architectural design. These developments demonstrate the great potential for further advancements of this new exciting research area.
Urinary protein quantification is critical for assessing the severity of chronic kidney disease (CKD). However, the current procedure for determining the severity of CKD is completed through ...evaluating 24-h urinary protein, which is inconvenient during follow-up.
To quickly predict the severity of CKD using more easily available demographic and blood biochemical features during follow-up, we developed and compared several predictive models using statistical, machine learning and neural network approaches.
The clinical and blood biochemical results from 551 patients with proteinuria were collected. Thirteen blood-derived tests and 5 demographic features were used as non-urinary clinical variables to predict the 24-h urinary protein outcome response. Nine predictive models were established and compared, including logistic regression, Elastic Net, lasso regression, ridge regression, support vector machine, random forest, XGBoost, neural network and k-nearest neighbor. The AU-ROC, sensitivity (recall), specificity, accuracy, log-loss and precision of each of the models were evaluated. The effect sizes of each variable were analysed and ranked.
The linear models including Elastic Net, lasso regression, ridge regression and logistic regression showed the highest overall predictive power, with an average AUC and a precision above 0.87 and 0.8, respectively. Logistic regression ranked first, reaching an AUC of 0.873, with a sensitivity and specificity of 0.83 and 0.82, respectively. The model with the highest sensitivity was Elastic Net (0.85), while XGBoost showed the highest specificity (0.83). In the effect size analyses, we identified that ALB, Scr, TG, LDL and EGFR had important impacts on the predictability of the models, while other predictors such as CRP, HDL and SNA were less important.
Blood-derived tests could be applied as non-urinary predictors during outpatient follow-up. Features in routine blood tests, including ALB, Scr, TG, LDL and EGFR levels, showed predictive ability for CKD severity. The developed online tool can facilitate the prediction of proteinuria progress during follow-up in clinical practice.
To realize the practical application of lithium–sulfur (Li–S) batteries, bifunctional binders featured with the capability of trapping soluble polysulfide species besides the strong binding property ...are highly desired. Herein, we demonstrate the strong potential of a commercially available, environmentally friendly, water-soluble linear polyethylenimine (PEI) as a superior bifunctional binder for high-sulfur-loading cathodes in Li–S batteries. Our investigation shows the significantly improved cathode performance with enhanced sulfur utilization (i.e., higher capacity), reduced capacity decay, and longer cycling life upon the use of PEI as the binder, relative to the traditional polyvinylidene fluoride (PVDF) binder. This arises from the significantly stronger binding strength and valuable polysulfide trapping ability of the linear PEI binder. In particular, its superior polysulfide adsorption capability has been evidenced experimentally with both ex situ and in situ studies, as well as through theoretical density functional theory (DFT) calculations. At a sulfur loading of 2.4 mg cm–2, the capacity decay rate of the cathode with the linear PEI binder is reduced to as low as 0.042% per cycle over 500 cycles at 2 C. In addition, it also enables the fabrication of high-sulfur-loading cathodes (as high as 6.5 mg cm–2) with high areal capacity (ca. 4.5 mAh cm–2) and high cycling stability. With its superior performance, linear PEI is promising for fabricating high-sulfur-loading cathodes of significantly lowered capacity decay for practical applications.
Designing reusable high‐performance heterogeneous palladium (Pd) catalysts via convenient, economic synthesis is of great importance to the industrial applications of various carbon‐carbon ...cross‐coupling reactions. We demonstrate herein a convenient one‐pot self‐encapsulation synthesis of a heterogeneous Pd catalyst Pd@PDEB, PDEB=poly(1,3‐diethynylbenzene) directly from commercially available, economic precursors. In the synthesis, the formation of the cross‐linked polymer networks and Pd encapsulation are accomplished simultaneously, turning a homogeneous Pd polymerization catalyst into the heterogeneous cross‐coupling catalyst. As a unique, practical heterogeneous catalyst, Pd@PDEB shows remarkably high activity, high reusability, and high versatility towards at least four types of cross‐coupling reactions (Suzuki–Miyaura, Stille, allylic arylation, and Mizoroki–Heck reactions) with even difficult reactants (aryl chlorides and heteroaryl halides) under aerobic conditions with Pd loadings down to ppm or even ppb levels. Evidences from hot filtration and 3‐phase tests demonstrate the heterogeneous nature of the catalyst with very low Pd leaching and negligible contributions of leached homogeneous Pd species towards the coupling reactions.
Obesity is an independent risk factor of development and progression of chronic kidney disease (CKD). Data on the benefits of bariatric surgery in obese patients with impaired kidney function have ...been conflicting.
To explore whether there is improvement in glomerular filtration rate (GFR), proteinuria or albuminuria after bariatric surgery.
We comprehensively searched the databases of MEDLINE, Embase, web of science and Cochrane for randomized, controlled trials and observational studies that examined bariatric surgery in obese subjects with impaired kidney function. Outcomes included the pre- and post-bariatric surgery GFR, proteinuria and albuminuria. In obese patients with hyperfiltration, we draw conclusions from studies using measured GFR (inulin or iothalamate clearance) unadjusted for BSA only. Study quality was evaluated using the Newcastle-Ottawa Scale.
32 observational studies met our inclusion criteria, and 30 studies were included in the meta-analysis. No matter in dichotomous data or in dichotomous data, there were statistically significant reduction in hyperfiltration, albuminuria and proteinuria after bariatric surgery.
The main limitation of this meta-analysis is the lack of randomized controlled trials (RCTs). Another limitation is the lack of long-term follow-up.
Bariatric surgery could prevent further decline in renal function by reducing proteinuria, albuminuria and improving glomerular hyperfiltration in obese patients with impaired renal function. However, whether bariatric surgery reverses CKD or delays ESRD progression is still in question, large, randomized prospective studies with a longer follow-up are needed.
Epidemiological evidence relating sleep disorders to end-stage renal disease (ESRD) has been obscure. The present study is sought to examine the association between sleep traits and ESRD.
For this ...analysis, we selected genetic instruments for sleep traits from published genome-wide association studies (GWAS). As instrumental variables, independent genetic variations linked with seven sleep-related features (sleep duration, getting up in the morning, daytime napping, chronotype of morning/evening person, sleeplessness/insomnia, non-snoring, and daytime dozing) were chosen. A two-sample Mendelian randomization (TSMR) study was conducted to assess the causal relationship between sleep traits and ESRD (N = 33,061). The reverse MR analysis subsequently determined the causal relationship between ESRD and sleep traits. The causal effects were estimated using inverse variance weighted, MR-Egger, weighted median. To conduct sensitivity studies, Cochran's Q test, MR-Egger intercept test, MR-PRESSO, leave-one-out analysis, and funnel plot were used. To study the potential mediators, multivariable mendelian randomization analyses were undertaken further.
Genetically predicted sleeplessness/ insomnia (OR = 6.11, 95%CI 1.00-37.3, P = 0.049, FDR = 0.105), getting up in the morning easily(OR = 0.23, 95%CI 0.063-0.85; P = 0.0278, FDR = 0.105), non-snoring (OR = 4.76E-02, 95%CI 2.29E-03-0.985, P = 0.0488, FDR = 0.105) was suggestively associated with the risk of ESRD. However, we found no evidence favoring a causal association between other sleep traits and ESRD through the IVW method.
The present TSMR found no strong evidence of a bidirectional causal association between genetically predicted sleep traits and ESRD.
A master oscillator power amplifier (MOPA) pulsed laser operating at 1342 nm is demonstrated. It consists of an acousto-optical (A-O) Q-switched oscillator and two-stage Nd: YVO
4
power amplifiers. ...The spherical aberration self-compensation technique is used in the second stage amplifier to obtain high-beam-quality laser output. The maximum average output power of 20.4 W is obtained with the oscillator power of 2.0 W and the total pump light power of 184.08 W, corresponding to an optical-optical efficiency of 11.08%. The repetition rate and pulse width are 100 kHz and 14.8 ns, respectively. The beam quality factor is M
x
2
=1.45 and M
y
2
=1.34. According to our knowledge, this is the maximum output power with a pulse width of ten-nanoseconds level and repetition rate of one-hundred-kilohertz level by an A-O Q-switch at the wavelength of 1342 nm.
We report in this article the convenient synthesis of a class of hyperbranched poly(phenylacetylene)s (HBPPAs) containing various branching densities and different contents of pendant alkyne groups ...through one-pot chain-growth copolymerization of phenylacetylene (PA) with a diyne comonomer (1,3- or 1,4-diethynylbenzene (DEB)). The polymerization was facilitated with the use of an in situ generated cationic diphosphine-ligated Pd(II) catalyst system. Serving effectively as difunctional cross-linker in the polymerization, the diyne comonomer first undergoes monoinsertion to render pendant alkyne groups, which can be further enchained to generate branching structures. A systematic investigation has been undertaken to study the effects of various polymerization parameters, including diyne/PA feed ratio, diyne type, temperature, and solvent, on the polymerization, polymer structure and topology. With either 1,3- or 1,4-DEB, a convenient tuning of polymer topology from linear to hyperbranched can be achieved by simply increasing diyne/PA feed ratio. Relative to 1,3-DEB, 1,4-DEB is more effective in rendering branching structures since the pendant alkyne groups suffer less steric effect from the polymer backbone and are thus more reactive. As to the solvent, a dichloromethane/methanol mixture (at vol. ratio of 13:3) was shown to better help the formation of branching structures than methanol alone as the resulting polymers can dissolve well in the former while precipitate in the latter. Because of their possession of the valuable pendant alkyne groups, these polymers have also been demonstrated for their use as building blocks in the synthesis of core–shell structured star polymers containing a HBPPA core and polystyrene arms through their Cu-catalyzed “click” reaction with an azide-ended polystyrene.
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