Zinc Metal–Organic Framework for Selective Detection and Differentiation of Fe(III) and Cr(VI) Ions in Aqueous Solution

A new luminescent Zn­(II)-based metal–organic framework (MOF), [Zn₂(TPOM)­(NDC)₂]·3.5H₂O (Zn-MOF; TPOM = tetrakis­(4-pyridyloxymethylene)­methane and H₂ndc = 2,6-naphthalenedicarboxylic acid), was successfully synthesized by a hydrothermal reaction. The MOF exhibits excellent luminescence emission, and it can detect Fe­(III) and Cr­(VI) ions with high selectivity, well antiinterference performance, and short response time. In addition, Zn-MOF was selected as a parent coordination compound to encapsulate Eu³⁺ cations to obtain a Eu³⁺-incorporated sample (Eu³⁺@Zn-MOF). Subsequently, we explored the potential application of Eu³⁺@Zn-MOF as a probe for the selective sensing of Fe­(III) and Cr­(VI) ions, and it revealed that we could differentiate Fe­(III) and Cr­(VI) ions by the combination Zn-MOF and Eu³⁺@Zn-MOF. More importantly, it represents the first example of MOF-based luminescent sensors which can detect and differentiate Fe­(III) and Cr­(VI) ions selectively. And the possible sensing mechanism was discussed in detail

Associations of <i>MTHFR</i> Gene Polymorphisms with Hypertension and Hypertension in Pregnancy: A Meta-Analysis from 114 Studies with 15411 Cases and 21970 Controls

<div><p>Background</p><p>Several epidemiological studies have investigated the associations of methylenetetrahydrofolate reductase (<i>MTHFR</i>) C677T and A1298C polymorphisms with hypertension (H) or hypertension in pregnancy (HIP). However, the results were controversial. We therefore performed a comprehensive meta-analysis to provide empirical evidences on the associations.</p><p>Methodologies</p><p>The English and Chinese databases were systematically searched to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. Meta-regression, subgroup analysis, sensitivity analysis, cumulative meta-analysis and assessment of publication bias were performed in our study.</p><p>Principal Findings</p><p>A total of 114 studies with 15411 cases and 21970 controls were included, 111 studies with 15094 cases and 21633 controls for the C677T polymorphism and 21 with 2533 cases and 2976 controls for the A1298C polymorphism. Overall, the C677T polymorphism was significantly associated with H and HIP (H & HIP: OR = 1.26, 95% CI = 1.17–1.34; H: OR = 1.36, 95% CI = 1.20–1.53; HIP: OR = 1.21, 95% CI = 1.08–1.32). Stratified analysis by ethnicity revealed a significant association among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans. In the stratified analyses according to source of controls, genotyping method, sample size and study quality, significant associations were observed in all the subgroups, with the exception of population based subgroup in H studies and large sample size and “others” genotyping method subgroups in HIP studies. For the A1298C polymorphism, no significant association was observed either in overall or subgroup analysis under all genetic models.</p><p>Conclusions</p><p>This meta-analysis suggests that the <i>MTHFR</i> C677T rather than A1298C polymorphism may be associated with H & HIP, especially among East Asians and Caucasians.</p></div

Summarized ORs with 95% CIs for the associations of <i>MTHFR</i> polymorphisms with H and HIP.

<p>Abbreviation: <i>MTHFR</i>, methylenetetrahydrofolate reductase; H, hypertension; HIP, hypertension in pregnancy; OR, odds ratio; CI, confidence interval; <i>P</i>_z, <i>P</i> value for association test; <i>P</i>_h, <i>P</i> value for heterogeneity test; <i>P</i>_e, <i>P</i> value for publication bias test; n, the number of studies.</p

Stratified analysis of the associations of <i>MTHFR</i> A1298C polymorphism with H and HIP under dominant model.

<p>Abbreviation: <i>MTHFR</i>, methylenetetrahydrofolate reductase; HWE, Hardy-Weinberg equilibrium; H, hypertension; HIP, hypertension in pregnancy; OR, odds ratio; CI, confidence interval; <i>P</i>_h, <i>P</i> value for heterogeneity test; n, the number of studies; PCR-RFLP, polymerase chain reaction-restriction fragment length polymorphism.</p

Flow diagram of study selection process in this meta-analysis.

<p>Flow diagram of study selection process in this meta-analysis.</p

Funnel plot analysis on the detection of publication bias in the meta-analysis of the associations between <i>MTHFR</i> polymorphisms and H & HIP (A: C677T and H & HIP; B: C677T and H; C: C677T and HIP; D: A1298C and H & HIP; E: A1298C and H; F: A1298C and HIP).

<p>Funnel plot analysis on the detection of publication bias in the meta-analysis of the associations between <i>MTHFR</i> polymorphisms and H & HIP (A: C677T and H & HIP; B: C677T and H; C: C677T and HIP; D: A1298C and H & HIP; E: A1298C and H; F: A1298C and HIP).</p

Distribution of <i>MTHFR</i> A1298C polymorphism among populations from 9 provinces in China.

<p>Abbreviation: <i>MTHFR</i>, methylenetetrahydrofolate reductase; AA, “wild-type” homozygosity; AC, heterozygosity; CC, mutant homozygosity; CI, confidence interval.</p>a<p>The 1298C allele frequencies were significantly different among the 9 populations (χ² = 406.85, <i>P</i><0.0001).</p>b<p>The 1298CC genotype frequencies were significantly different among the 9 populations (χ² = 130.73, <i>P</i><0.0001).</p>*<p>The 1298C allele frequencies were significantly different from the southern populations (χ² = 5.40, <i>P = </i>0.0201).</p>#<p>The 1298 CC genotype frequencies were significantly different from the southern populations (χ² = 4.27, <i>P = </i>0.0389).</p

Frequencies of <i>MTHFR</i> C677T genotypes and alleles by gender^a.

<p>Abbreviations: <i>MTHFR</i>, methylenetetrahydrofolate reductase; CC, “wild-type” homozygosity; CT, heterozygosity; TT, mutant homozygosity; CI, confidence interval.</p>a<p>All participants were from Tianjin municipality.</p>b<p>The 677T allele and the 677TT genotype frequencies were not significantly different from females (χ² = 0.23, <i>P = </i>0.6321 and χ² = 0.26, <i>P = </i>0.6157, respectively).</p

Frequencies of <i>MTRR</i> A66G genotypes and alleles by gender^a.

<p>Abbreviations: <i>MTRR</i>, methionine synthase reductase; AA, “wild-type” homozygosity; AG, heterozygosity; GG, homozygosity; CI, confidence interval.</p>a<p>All participants were from Tianjin municipality.</p>b<p>The 66G allele and the 66GG genotype frequencies were not significantly different from females (χ² = 2.89, <i>P = </i>0.0893 and χ² = 1.11, <i>P = </i>0.2930, respectively).</p

Distribution of <i>MTHFR</i> C677T polymorphism among populations from 10 regions in China^a.

<p>Abbreviation: <i>MTHFR</i>, methylenetetrahydrofolate reductase; CC, “wild-type” homozygosity; CT, heterozygosity; TT, mutant homozygosity; CI, confidence interval.</p>a<p>The 10 regions include 9 provinces (Shandong, Henan, Shannxi, Jiangsu, Hubei, Yunnan, Guangdong, and Hainan) and 1 municipality (Tianjin).</p>b<p>The 677T allele frequencies were significantly different among the 10 populations (χ² = 2166.61, <i>P</i><0.0001).</p>c<p>The 677TT genotype frequencies were significantly different among the 10 populations (χ² = 1242.20, <i>P</i><0.0001).</p>*<p>The 677T allele frequencies were significantly different from the southern populations (χ² = 6.55, <i>P = </i>0.0105).</p>#<p>The 677TT genotype frequencies were significantly different from the southern populations (χ² = 6.59, <i>P = </i>0.0103).</p