Tailoring of Porous Structure in Macro-Meso-Microporous SiC Ultrathin Fibers <i>via</i> Electrospinning Combined with Polymer-Derived Ceramics Route

<p>Porous SiC has attracted extensive attention for its wide applications, especially in harsh environment, due to its unique properties. In the present paper, novel macro-meso-microporous SiC ultrathin fibers (MMM-SFs) were synthesized through electrospinning process associated with polymer-derived ceramics route, and the porous structure in the SFs can be conveniently tailored by tuning the composition of the spinning solvents and the concentration of the precursor (polycarbosilane). The surface features and microstructures of the resultant MMM-SFs were characterized in detail. These fibers presented a high specific surface area of 86.1–128.2 m² g⁻¹. The formation mechanism of hierarchically porous structure was discussed as well. <i>N,N</i>′-dimethylformamide (DMF) played a critical role in forming macropores, while the decomposition of SiO_<i>x</i>C_<i>y</i> phase was responsible for the meso-/micropores. Our method utilized to synthesize hierarchically porous SFs is easily capable of designing other ceramic fibers.</p

Prevalence of Goiter and Thyroid Nodules before and after Implementation of the Universal Salt Iodization Program in Mainland China from 1985 to 2014: A Systematic Review and Meta-Analysis

<div><p>Objectives</p><p>We comprehensively estimated the prevalence of goiter and thyroid nodules (TNs) before and after the implementation of the Universal Salt Iodization (USI) program in mainland China and provided information for creating effective health policies.</p><p>Methods</p><p>PubMed, Google Scholar, CNKI, Chinese Wanfang and Chongqing VIP databases were searched for relevant studies from Jan 1985 to Feb 2014. Data from eligible citations were extracted by two independent reviewers. All analyses were performed with Stata 11.0 and SPSS 17.0.</p><p>Results</p><p>Eligible articles (N = 31; 4 in English and 27 in Chinese) included 52 studies (15 about goiter rates made before 1996 and 14 afterwards, and 23 about TNs). Our meta-analysis suggests a pooled prevalence for goiter before and after 1996 and for TNs of 22.8% (95% CI: 15.3%, 30.3%), 12.6% (95% CI: 9.4%, 15.8%) and 22.7% (95% CI: 18.3%, 27.0%), respectively. Egger's test of three independent categories revealed no evidence of publication bias (<i>p</i> = 0.101, 0.148 and 0.113, respectively).</p><p>Conclusions</p><p>The prevalence of goiter was reduced by almost half after 1996 in mainland China, so the USI program was considered beneficial. However, subgroup analysis suggests that both insufficient and excess iodine may be associated with goiter. The prevalence of goiter and TNs increased significantly after 2002, suggesting a risk of excessive iodine intake. Thus, salt iodization standardizations should be set according to local conditions.</p></div

Photocurrent Response in Multiwalled Carbon Nanotube Core–Molybdenum Disulfide Shell Heterostructures

In this report, a few-layer molybdenum disulfide (MoS₂) shell was coated on core multiwalled carbon nanotube (CNT) by a facile solvothermal method. The morphology and high crystallinity of this structure were demonstrated and verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). After being integrated into a planar device, the CNT–MoS₂ core–shell structure exhibits clear photoresponse and a wide response range upon laser illumination. In addition, the device shows a bias-dependent and position-sensitive photocurrent effect. Further experiments show that larger photocurrent was obtained under laser illumination with longer wavelength. Both the photocurrent and response speed are enhanced when the device is placed under vacuum condition. The simple material synthesis and device fabrication method used in this work may provide a practical strategy for low-cost and large-scale optical applications

Subclinical Hypothyroidism and Type 2 Diabetes: A Systematic Review and Meta-Analysis

<div><p>Background</p><p>Abundant evidence suggests an association between subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (T2DM), but small sample sizes and inconclusive data in the literature complicate this assertion.</p><p>Objective</p><p>We measured the prevalence of SCH in T2DM population, and investigated whether T2DM increase the risk of SCH and whether SCH was associated with diabetic complications.</p><p>METHODS</p><p>We conducted a meta-analysis using PubMed, EMBASE, Web of Science, Wan Fang, CNKI and VIP databases for literature search. We obtained studies published between January 1, 1980 to December 1, 2014. The studies were selected to evaluate the prevalence of SCH in T2DM subjects, compare the prevalence of SCH in T2DM subjects with those non-diabetics, and investigate whether diabetic complications were more prevalent in SCH than those who were euthyroid. Fixed and random effects meta-analysis models were used, and the outcome was presented as a pooled prevalence with 95% confidence interval (95% CI) or a summary odds ratio (OR) with 95% CI.</p><p>RESULTS</p><p>Through literature search, 36 articles met the inclusion criteria and these articles contained a total of 61 studies. Funnel plots and Egger’s tests showed no publication bias in our studies, except for the pooled prevalence of SCH in T2DM (<i>P</i> = 0.08) and OR for SCH in T2DM (<i>P</i> = 0.04). Trim and fill method was used to correct the results and five potential missing data were replaced respectively. The adjusted pooled prevalence of SCH in T2DM patients was 10.2%, meanwhile, T2DM was associated with a 1.93-fold increase in risk of SCH (95% CI: 1.66, 2.24). Furthermore, SCH might affect the development of diabetic complications with an overall OR of 1.74 (95% CI: 1.34, 2.28) for diabetic nephropathy, 1.42 (95% CI: 1.21, 1.67) for diabetic retinopathy, 1.85 (95% CI: 1.35, 2.54) for peripheral arterial disease, and 1.87 (95% CI: 1.06, 3.28) for diabetic peripheral neuropathy.</p><p>Conclusions</p><p>T2DM patients are more likely to have SCH when compared with healthy population and SCH may be associated with increased diabetic complications. It is necessary to screen thyroid function in patients with T2DM, and appropriate individualized treatments in addition to thyroid function test should be given to T2DM patients with SCH as well.</p></div

Forest plot of the pooled prevalence of TNs in mainland China.

<p>Forest plot of the pooled prevalence of TNs in mainland China.</p

Trim and fill analysis for odds ratio of SCH in T2DM.

<p>Trim and fill analysis for odds ratio of SCH in T2DM.</p

Odds ratio for PAD in T2DM with SCH.

<p>Odds ratio for PAD in T2DM with SCH.</p

Trim and fill analysis for prevalence of SCH in T2DM.

<p>Trim and fill analysis for prevalence of SCH in T2DM.</p

Prevalence of Subclinical hypothyroidism in patients with type 2 diabetes by different stratification factors.

<p>Prevalence of Subclinical hypothyroidism in patients with type 2 diabetes by different stratification factors.</p

Characteristics of the studies included in the meta-analysis for the summarized prevalence of SCH in T2DM patients.

<p>a, Mean ages were expressed in mean ± SD or mean.</p><p>b, These original articles did not provide the mean age of the total population, so age data was extracted according to the age characteristics mentioned in the articles included.</p><p>c, adjusted pooled prevalence.</p><p>Abbreviation: F, female; M, male; C, subjects without SCH; S, subjects with SCH; TSH, thyroid stimulating hormone; CC, case control study; CSS, cross-sectional study.</p><p>Characteristics of the studies included in the meta-analysis for the summarized prevalence of SCH in T2DM patients.</p