A trinity strategy enabled by iodine-loaded nitrogen-boron-doped carbon protective layer for dendrite-free zinc-ion batteries

Although aqueous zinc ion batteries (AZIBs) have the merits of environmental friendliness, high safety and theoretical capacity, the slow kinetics associated with zinc deposition and unavoidable interfacial corrosion have seriously affected the commercialization of aqueous zinc ion batteries. In this work, an ingenious "trinity" design is proposed by applying a porous hydrophilic carbon-loaded iodine coating to the zinc metal surface (INBC@Zn), which simultaneously acts as an artificial protective layer, electrolyte additive and anode curvature regulator, so as to reduce the nucleation overpotential of Zn and promote the preferential deposition of (002) planes to some extent. With this synergistic effect, INBC@Zn exhibits high reversibility and strong side reaction inhibition. As a result, INBC@Zn shows high symmetric cycling stability up to 4500 h at 1 mA cm-2. An ultra-long cycle stability of 1500 cycles with high Coulombic efficiency (99.8 %) is achieved in the asymmetric cell. In addition, the INBC@Zn//NVO full cells exhibit impressive capacity retention (96 % after 1000 cycles at 3 A/g). Importantly, the designed pouch cell demonstrates stable performance and shows certain prospects for application. This work provides a facile and instructive approach toward the development of high-performance AZIBs.

Bimetallic mutual-doping magnetic aerogels for iodine reduction capture and immobilization

Adsorption is considered to be one of the most effective methods to remove radioiodine from the solution. However, developing highly efficient adsorbents and the rapid recovery of the used adsorbents is still a challenge. Here, a series of Cu/Fe3O4 bimetallic mutual-doping magnetic aerogels (Cu/Fe3O4-BMMA) were synthesized. Based on the in-situ bimetallic co-gelation process, the high dispersion of Cu in the aerogel was realized, providing conditions for the efficient elimination of I2. The Fe3+ in the initial gel was reduced to magnetic Fe3O4 during the preparation process, allowing for the quick recovery of the adsorbent through the application of a magnetic field. The adsorption experiments showed that Cu/Fe3O4-BMMA has good I2 adsorption capacity (631.3 mg/g) and fast capture kinetics (equilibrium time < 30 min). In addition, Cu/Fe3O4-BMMA was able to effectively remove trace I2 in the solution from ppm level (1.0 ppm) down to ppb level (≤30 ppb). The adsorbed I2 was converted into stable CuI, avoiding secondary pollution due to desorption. Overall, this study provides a potentially efficient iodine capture material for long-term decay storage of radioactive iodine.

Key concepts in clinical epidemiology: detecting and dealing with heterogeneity in meta-analyses

In a meta-analysis, a question always arises. Is it worthwhile to combine estimates from studies of different populations using various formulations of an intervention, evaluating outcomes measured differently? Sometimes even study designs differ. Differences are expected in a meta-analysis. These may be negligible, and a pooled estimate of effect can guide the clinical decision. However, when the differences are large, this estimate may mislead. Effect estimates from study to study differ because of real differences (between-study variability) and because of chance (within-study variability). To combine estimates when there is heterogeneity (between-study differences are large) may not be sensible. Two complementary methods may be used to detect heterogeneity: visual inspection of the forest plot and calculating numerical measures of heterogeneity (I² and Q). Visual inspection can show effects that are different from the rest. A large I² (proportion of overall variability attributed to between-study variation) or a small P-value associated with Q may suggest heterogeneity. Large P-values, however, do not mean the absence of heterogeneity. It is more informative to report the confidence interval of the I². If there is no heterogeneity, a pooled estimate of the true effect may be generated using only within-study variation (fixed-effect model). If there is substantial heterogeneity, reasons should be sought. Subgroup analysis or meta-regression using study-level characteristics may be done. Although more involved and potentially challenging, individual-level data (Individual Participant Data, IPD) may also be used. In the case of unexplained heterogeneity, both within- and between-study variation should be used to generate a pooled estimate (random-effects model). This estimate does not estimate a single true effect but estimates the average of a range of effects of the intervention on populations represented by the studies. If precise enough (narrow confidence interval), this estimate, together with the prediction interval (a measure of uncertainty in the effect one might see in a particular context), can guide clinical and policy decisions.

Heterogeneity in Cochrane and non-Cochrane meta-analyses in orthodontics

OBJECTIVES

Heterogeneity describes the percentage of variability across the study effects that can be attributed to between-study differences in a meta-analysis. The aim of this project was to explore the magnitude of heterogeneity in Cochrane and non-Cochrane meta-analyses in orthodontic research and to identify possible associations between heterogeneity (I²) and a number of study characteristics including number of studies, type of outcome and type of analysis.

METHODS

The contents of five major orthodontic journals and the Cochrane Database of Systematic Reviews were electronically searched from January 2000 to December 2017 to identify Systematic Reviews (SRs) with at least one meta-analysis. Included records were screened for reporting of I² classified into four categories: 0%, 1-29%, 30-59%, 60-100%. Associations between I² and review-level and synthesis-level characteristics were tested. Univariable and multivariable mixed effects ordinal logistic regression was used to identify significant predictors for statistical heterogeneity.

RESULTS

A total of 72 SRs comprising 391 meta-analyses were included with the majority based on non-Cochrane reviews (n = 54, 75%). Overall, 125 meta-analyses (32%) reported heterogeneity explained by chance (I² = 0%), whereas high values of I² (∼60-100%) were seen in 152 syntheses (39%). In the multivariable analysis, inclusion of each additional study within the synthesis presented 20% higher odds for substantial/considerable heterogeneity compared to lower heterogeneity categories (OR = 1.20; 95%CIs: 1.09, 1.31; p < 0.001). Use of fixed effect analysis (OR = 0.25; 95%CIs: 0.12, 0.55; p = 0.001) was associated with significantly lower odds. Cochrane versus non-Cochrane meta-analyses were not associated with higher odds for substantial/considerable heterogeneity (OR = 2.81; 95%CIs: 0.53, 14.91; p = 0.22).

CONCLUSIONS

Substantial statistical heterogeneity is present within a considerable number of orthodontic meta-analyses. Further efforts should be made to improve understanding of decisions to undertake meta-analyses and selection of studies eligible for inclusion.

CLINICAL SIGNIFICANCE

The consistency of meta-analyses could be improved with more careful consideration of individual study characteristics. Reduced heterogeneity in meta-analyses will ensue more solid evidence based decisions for clinical practice.

A useful PET probe [11C]BU99008 with ultra-high specific radioactivity for small animal PET imaging of I2-imidazoline receptors in the hypothalamus

INTRODUCTION

A positron emission tomography (PET) probe with ultra-high specific radioactivity (SA) enables measuring high receptor specific binding in brain regions by avoiding mass effect of the PET probe itself. It has been reported that PET probe with ultra-high SA can detect small change caused by endogenous or exogenous ligand. Recently, Kealey et al. developed [¹¹C]BU99008, a more potent PET probe for I₂-imidazoline receptors (I₂Rs) imaging, with a conventional SA (mean 76GBq/μmol) showed higher specific binding in the brain. Here, to detect small change of specific binding for I₂Rs caused by endogenous or exogenous ligand in an extremely small region, such as hypothalamus in the brain, we synthesized and evaluated [¹¹C]BU99008 with ultra-high SA as a useful PET probe for small-animal PET imaging of I₂Rs.

METHODS

[¹¹C]BU99008 was prepared by [¹¹C]methylation of N-desmethyl precursor with [¹¹C]methyl iodide. Biodistribution, metabolite analysis, and brain PET studies were conducted in rats.

RESULTS

[¹¹C]BU99008 with ultra-high SA in the range of 5400-16,600GBq/μmol were successfully synthesized (n=7), and had appropriate radioactivity for in vivo study. In the biodistribution study, the mean radioactivity levels in all investigated tissues except for the kidney did not show significant difference between [¹¹C]BU99008 with ultra-high SA and that with conventional SA. In the metabolite analysis, the percentage of unchanged [¹¹C]BU99008 at 30min after the injection of probes with ultra-high and conventional SA was similar in rat brain and plasma. In the PET study of rats' brain, radioactivity level (AUC_{30-60 min}) in the hypothalamus of rats injected with [¹¹C]BU99008 with ultra-high SA (64 [SUV ∙ min]) was significantly higher than that observed for that with conventional SA (50 [SUV ∙ min]). The specific binding of [¹¹C]BU99008 with ultra-high SA (86% of total binding) for I₂R was higher than that of conventional SA (76% of total binding).

CONCLUSION

A PET study using [¹¹C]BU99008 with ultra-high SA would thus contribute to the detection of small changes in or small regions with I₂R expression and hence may be useful in elucidating new functions of I₂R.