Haplotype-based approach for noninvasive prenatal tests of Duchenne muscular dystrophy using cell-free fetal DNA in maternal plasma.

PURPOSE: This study demonstrates noninvasive prenatal testing (NIPT) for Duchenne muscular dystrophy (DMD) using a newly developed haplotype-based approach. METHODS: Eight families at risk for DMD were recruited for this study. Parental haplotypes were constructed using target-region sequencing data from the parents and the probands. Fetal haplotypes were constructed using a hidden Markov model through maternal plasma DNA sequencing. The presence of haplotypes linked to the maternal mutant alleles in males indicated affected fetuses. This method was further validated by comparing the inferred single-nucleotide polymorphism (SNP) genotypes to the direct sequencing results of fetal genomic DNA. Prenatal diagnosis was confirmed with amniocentesis, and those results were interpreted in a blinded fashion. RESULTS: The results showed an average accuracy of 99.98% for the total inferred maternal SNPs. With a mean depth of 30× achieved in the 10-Mb target region of each sample, the noninvasive results were consistent with those of the invasive procedure. CONCLUSION: This is the first report of NIPT for DMD and the first application of a haplotype-based approach in NIPT for X-linked diseases. With further improvements in accuracy, this haplotype-based strategy could be feasible for NIPT for DMD and even other X-linked single-gene disorders.

Electrochemical milling and faceting: size reduction and catalytic activation of palladium nanoparticles.

Improved performance through milling: A method for enhancing the catalytic activity of supported metal nanoparticles is reported. This method enhances the activity for the ethanol electro-oxidation of a supported palladium catalyst. The much higher catalytic performance is ascribed to the increased electrochemically active surface area as well as the generation of high-index facets at the milled nanoparticle surface.

Tuning the shape and catalytic activity of Fe nanocrystals from rhombic dodecahedra and tetragonal bipyramids to cubes by electrochemistry.

Fe nanocrystal catalysts were synthesized by electrochemistry. Shape transformations of Fe nanocrystals from rhombic dodecahedra and tetragonal bipyramids, both bounded by {110} facets, to 18-facet polyhedra enclosed by different combinations of {110} and {100} facets and finally to cubes exclusively covered by {100} facets have been achieved. A study of the surface-structure functionality of the Fe nanocrystals toward electroreduction of nitrite revealed that the electrocatalytic activity of the Fe nanocrystals increases as the fraction of {100} facets on the surface of the Fe NCs increases.

[Investigation of electrocatalytic reduction of oxalic acid on Pb electrode through in situ FTIR reflection spectroscopy].

Electrochemical in situ Fourier transform infrared reflection spectroscopy was used in the investigation of electrocatalytic reduction of oxalic acid on Pb electrode. The multi-step potential FTIRS and time-resolved FTIRS procedures were used in the present study. The results of MSFTIRS demonstrate that glyoxylic acid could be detected below -0.70 V. The quantity of glyoxylic acid cumulated on Pb electrode surface reaches a maximum at -0.85 V, then it decreases as electrode potential is further decreased. Meanwhile the C-O stretching vibration of -CH2OH group at around 1 093 cm(-1) could be detected at -0.95 V. It was revealed that all the produced glyoxylic acid may be reduced further into glycolic acid at potentials below -1.50 V. Furthermore, none of other new substances could be detected at more negative potentials, which indicated that glycolic acid could not be further reduced. The results of time resolved Fourier transform infrared reflection spectroscopy at -0.75 V indicate that the integrated intensity of the IR band at about 1 750 cm(-1) for the stretching vibration of C=O (-CHO) linearly increases with the reaction time. The TRFTIR spectra at -1.60 V show that not only the IR absorption of C=O (HOOC-CHO) stretching is observed, but also that of C-O (-CH2OH) stretching at about 1 093 cm(-1) can be seen. The current study demonstrated that electrochemical in situ Fourier transform infrared reflection spectroscopy is a powerful tool for the study of electrosynthesis processes, and for the detection of each species involved in the reaction at molecular level. The results are of significance to understand the reaction mechanism of electrocatalytic reduction of oxalic acid.

[Ethanol electrooxidation on carbon supported PtSn catalyst: in situ TRFTIR study].

Carbon supported PtSn catalyst (PtSn/C) was prepared by a modified polyol method and characterized by means of XRD. It was showed that the metal particle size was 2.2 nm and the unit cell parameter increased compared with Pt/C. In situ time-resolved Fourier transform infrared spectroscopy (TRFTIRS) was used to study the electrooxidation of ethanol on PtSn/C catalyst. COL was the main poison species adsorbed on the active sites to inhibit the further reaction of ethanol electrooxidation. Acetaldehyde and acetic acid were found to be the products of ethanol electrooxidation as competing reactions with ethanol dissociation when the potential was up to 0.3 V, which reduced the poisoning effect. The selectivity of acetic acid among the products was improved with the increase in the potential and reaction time. CO2, which appeared at 0.4 V, was the final product and yielded from the oxidation of COL. The catalytic mechanism of PtSn/C towards ethanol electrooxidation was analyzed based on the results.

[EQCM and in situ FTIR studies on the adsorption and oxidation of 1-butanol at a platinum electrode in alkaline media].

The adsorption and oxidation of 1-butanol in alkaline media on a platinum electrode were investigated mainly by EQCM and in situ FTIR spectroscopy. The experimental results demonstrate that the electrooxidation of 1-butanol is closely relative to solution acidity. Since no chemically adsorbed species, such as CO, were evidenced by in situ FTIR spectroscopy, the adsorption of 1-butanol or its dissociative products on Pt surface is suggested by EQCM and CV data. Only one current peak of 1-butanol oxidation in PGPS was detected at -0.23 V/SCE, which illustrated the disappearance of the second current peak due to Pt electrode passivation in alkaline media. The final product of 1-butanol oxidation is only butyric acid anion under experimental condition. It may therefore be suggested that the main reaction occurring at the electrode is the oxidation of 1-butanol to butyric acid anion. The EQCM studies provide quantitative results of surface mass variation and have shed light on elucidating 1-butanol oxidation.

A new method of ion chromatography technology for speedy determination and analysis in organic electrosynthesis of glyoxylic acid.

Based on ion chromatography (IC) technology, we have developed a new method that combines ion chromatography with a conductivity detector to separate and determine the substances of glyoxal, glycolic acid, oxalic acid and glyoxylic acid. The ion chromatography was applied for the first time in quantitative determination of substances involved in electrosynthesis of glyoxylic acid. The method has been applied to separate and analyze simultaneously either glyoxylic acid and glyoxal in electroxidation of glyoxal, or glyoxylic acid and oxalic acid in electroreduction of oxalic acid. An aqueous Na2CO3-NaHCO3 or NaOH-Na2CO3 solution was confirmed to be the most desirable eluent. The experimental results demonstrated that the detection sensitivity is ahead of ppm grade, and the variation coefficients such as the retention time, the peak height and the peak area outperform 2%. All the recoveries of the detected substances are ranged between 97 and 103%. The method exhibits advantages of high selectivity, high sensitivity, speediness and simple apparatus requirement. Furthermore, simultaneous determination of a mixture of several substances can be achieved by the developed method, and even a neutral molecule of glyoxal can be also determined by choosing an appropriate composition and concentration of eluent.

[In situ FTIR spectroscopy studies of HCOOH oxidation on surface alloy electrocatalysts].

Electrocatalytic properties of three electrodes for formic acid oxidation were studied by using electrochemical in situ FTIR spectroscopy and cyclic voltammetry in this paper. It is demonstrated that the electrocatalytical mechanism of formic acid oxidation on platinum-dispersed carbon(Pt/GC) is similar to that on massive platinum, which involves two paths, i.e. one way through active intermediate and the other through poison intermediate to CO2. The Pt/GC exhibits higher catalytivity than pure platinum. The electrode of Pt/GC modified by Sb (Sb-Pt/GC) was also prepared in the work. It was observed that the onset potential (Ei) for formic acid oxidation on Sb-Pt/GC was shift negatively for 0.20 V. The peak potential (Ep) was observed to shifted negatively to 0.34 V and the value of oxidation current (jp) was enhanced nearly 7.28 times. Similar results were also observed on surface alloy/GC prepared. In this case, Ei and Ep were -0.12 and 0.32 V, respectively, jp was enhanced about 8.15 times, and FWHM (full width at half maximum) was 0.50 V. It is indicated that Sb-Pt/GC and surface alloy/GC can not only effectively restrain the formation of poison intermediate CO, but also significantly increase the electrocatalytic activities for oxidation of active intermediates.

[Solid/liquid interfacial in situ IR microscope and step-scan time-resolved FTIR spectroscopy and applications in studies of nanomaterials].

Electrochemical in situ microscope IR reflection spectroscopy and step-scan time-resolved FTIR reflection spectroscopy were established by using an IR-plan advantage microscope and a Nexus 870 FTIR instrument, and a home-made signal synchronizer that harmonizes electrode polarization potential and step-scan spectral data collection sequence. These new techniques have been applied in studies of particular IR properties of 2-dimensional nanomaterials. By applying a treatment of fast potential cycling with different time (tau), a set of nanostructured Pt microelectrodes were prepared. CO adsorption was employed as a probe reaction together with in situ developed microscope FTIR spectroscopy. The results illustrated the variation of abnormal IR features with the nanostructure and the thickness (i.e., the size) of film formed on Pt microelectrode, i.e., following the increase of tau in fast potential cycling treatment, the direction of CO band was turned from absorption to antiabsorption direction, and the intensity and the width of CO band were increased. By taking the advantage of the abnormal infrared effects of nanostructured Pt microelectrode, the sensitivity of in situ IR reflection spectroscopy has been significantly improved, and spectra of time-resolution as fast as 50 micros have been recorded at solid/liquid interfaces. The current studies demonstrated not only the success of development of new techniques of in situ IR spectroscopy, but also the exploitation of the established techniques in studies of nanomaterials.

Electrochemically shape-controlled synthesis in deep eutectic solvents: triambic icosahedral platinum nanocrystals with high-index facets and their enhanced catalytic activity.

Pt triambic icosahedral nanocrystals (TIH NCs) enclosed by {771} high-index facets were successfully synthesized electrochemically, for the first time, in ChCl-urea based deep eutectic solvents, and exhibited higher electrocatalytic activity and stability towards ethanol electrooxidation than a commercial Pt black catalyst.

Anomalous IR properties of nanostructured films created by square wave potential on an array of Pt microelectrodes: an in situ microscope FTIRS study of CO adsorption.

Thin films of different nanostructures on an array of nine Pt microelectrodes were prepared by applying a square wave potential treatment for different times (tau). It has been measured from the cyclic voltammetric studies that the relative surface roughness of the films was increased slightly and reached a maximal value of about 2.5. SEM studies demonstrated that with the increase of tau, the growth of island-shaped Pt crystallites on the films led to the formation of plumelike crystallites that can reach about 2-3.5 microm in length when tau exceeded 70 min. In situ microscope FTIR reflection spectroscopic studies illuminated that CO adsorbed on the array yielded different anomalous IR features. With the increase of tau, the direction of the CO L band (linearly bonded CO) was transformed from the negative-going direction (normal IR adsorption) to bipolar (Fano-like spectral line shape) and finally to the positive-going direction (abnormal IR adsorption). The intensity of the CO L band was enhanced significantly and a maximal enhancement factor of about 33 was measured when tau was 40 min; the center of the CO L band and the Stark tuning rate also showed regular changes. This study demonstrated that specific nanostructures of Pt thin films can be prepared through a square wave potential treatment for different times and revealed the intrinsic relationship between anomalous IR properties and surface nanostructures of the thin films.