Detection of cell-free fetal DNA in maternal plasma using two types of compound markers

With the discovery of circulating cell-free fetal DNA (cffDNA) in maternal plasma, noninvasive prenatal testing became possible. However, analysis of low-level cffDNA against high background maternal DNA remains complicated and challenging. To circumvent this limitation, selective amplification of cffDNA was used in this study. Two kinds of compound markers (namely DIP-STR and SNP-STR), both based on selective amplification, were used here for targeting fetal DNA. By designing two allele-specific forward primers for DIP-STR and SNP-STR, DNA fragments with different DIP/SNP alleles can be selectively amplified. When analyzing maternal plasma DNA, these markers can selectively target paternally inherited fetal alleles whose DIP/SNP allele was not shared with the mother. In this study, 21 families were studied with six DIP-STRs and 11 SNP-STRs. Fetal DNA was successfully detected across plasma samples for at least one marker. Detection rate varied between DIP-STR and SNP-STR markers, and DIP-STR outperforms SNP-STR. Fetal alleles obtained from maternal plasma were double confirmed by genotyping paternal genomic DNA and fetal genomic DNA from amniocentesis. This study demonstrated that selective amplification strategy can be used to target cffDNA in maternal plasma, which will be a promising method for noninvasive prenatal paternity testing.     

用于无创产前诊断的SRY基因高灵敏高特异检测方法研究

通过检测母体外周血中胎儿游离DNA(cffDNA)的SRY基因,确定胎儿性别,可评估胎儿性连锁遗传病的发病风险,降低病儿出生率.本研究建立了高灵敏、高特异、闭管检测不易污染的实时荧光PCR偶联核酸侵入反应方法用于SRY基因的检测.通过优化反应体系中的检测探针浓度、FEN1酶用量、Taq酶用量及预扩增退火温度,确定了最佳的反应条件,即检测探针浓度为250 nmol/L、FEN1酶用量为7.5 U、Taq酶用量为0.5 U、预扩增退火温度为67℃.在最佳反应条件下,实现对含量低至4%(4 copies/μL)的模拟样本的检测,并成功检测两例孕期分别为9周和10周的临床实际样本.结果表明,所建立的方法可用于母体外周血cffDNA的SRY基因检测,为临床开展基于SRY基因的无创产前诊断提供了新方法.     

Quantities of adult, fetal and embryonic globin chains in the blood of eighteen- to twenty-week-old human fetuses

The prenatal diagnostic program, established at Hacettepe University in Ankara for the purpose of detecting beta-thalassemia (beta-thal), sickle cell anemia (SS), and Hb S-beta-thal, offered the opportunity of evaluating the relative quantities of adult (beta A, beta S), fetal (G gamma, A gamma, A gamma T), and embryonic (epsilon, zeta) chains in 26 fetuses, aged 18-20 weeks. Methodology involved micro high-performance liquid chromatographic (HPLC) procedures and immunology using an mAb, specific for the embryonic epsilon chain. A good correlation was observed between the beta/gamma in vitro chain synthesis ratio and the level of beta A and/or beta S chains determined by reversed-phase HPLC; the combination of these two sets of data strengthens the prenatal diagnostic approach of detecting beta-thal major but not beta-thal trait. The levels of the different gamma chains were about as observed in newborn babies; the frequency of the A gamma T variant in the 26 fetuses was the same as observed for a larger group of Turkish newborn babies. The level of the embryonic zeta chain was higher than seen in full-term babies and varied between 0 and 1.3%; 5 of the 26 fetuses showed the complete absence of zeta. The embryonic epsilon chain was not detectable, not even in babies with beta-thal major. These data indicate that the synthesis of epsilon is completely turned off in fetuses at the age of 18-20 weeks, while that of zeta continues, albeit at a low level.     

Biological matrices for the evaluation of exposure to environmental tobacco smoke during prenatal life and childhood

The measurement of nicotine and its major metabolites cotinine and trans-3´-hydroxicotinine together with other minor metabolites (e.g., cotinine N-oxide, cotinine, and trans-3´-hydroxicotinine glucuronides) in conventional and nonconventional biological matrices has been used as a biomarker to assess the exposure to environmental tobacco smoke during childhood. The determination of these substances in matrices such as amniotic fluid, meconium, and fetal hair accounts for prenatal exposure to cigarette smoking at different stages of pregnancy. Nicotine and its metabolites in cord blood, neonatal urine, and breast milk are useful for determining acute exposure to drugs of abuse in the period immediately before and after delivery. Cotinine measurement in children’s blood and urine and nicotine and cotinine measurements in children’s hair constitute objective indexes of acute and chronic exposure during infancy, respectively. However, for monitoring and categorizing cumulative exposure to environmental tobacco smoke during the entire childhood, including the prenatal period, the assessment of nicotine in teeth has been proposed as a promising noninvasive tool. This article reviews the usefulness of measurement of nicotine and its metabolites in different fetal and pediatric biological matrices in light of noninvasive collection, time window of exposure detection, and finally clinical application in pediatrics.     

Simultaneous forward and reverse ABO blood group typing using a paper-based device and barcode-like interpretation

A new platform of a paper-based analytical device (PAD) for simultaneous forward and reverse ABO blood group typing has been reported. This platform can overcome the discrepancy results as influenced by the individual haematocrit. The test and the control of non-haemagglutination on each channel were performed in parallel. The PAD was fabricated by printing six parallel channels with wax onto Whatman No. 4 filter paper. An LF1 blood separation membrane was used for the separation of plasma from whole blood for reverse grouping. The blood group was identified by haemagglutination of the corresponding antigen–antibody. For forward grouping, Anti-A, -B and –A,B were treated on the test line of PAD, and inactivated Anti-A, -B and –A,B were immobilized on the control line. For reverse grouping, 30% standard A-cells, B- and O- were added to the test channel after plasma separation, and O-cells were used as a control. Then, 0.9% normal saline (NSS) containing 1% Tween-20 was bi-functionally used for dilution of the blood sample and elution of the non-agglutinated RBCs within the channels. The distance of agglutinated RBCs in each test line was compared with the distance of non-agglutinated RBCs in the parallel control line. The forward and reverse patterns of blood groups A, B, AB and O were a barcode-like chart in which the results can be visually analysed. The PAD has excellent reproducibility when 10 replications of the A, B, AB or O blood groups were performed. The results of both forward and reverse grouping were highly correlated with conventional methods compared with the slide method and tube method, respectively (n = 76). Thus, this ABO typing PAD holds great potential for future applications in blood typing point-of-care testing.     

产前超声联合MRI对胎儿中枢神经系统畸形的筛查价值

本文对产前超声联合核磁共振成像（MRI）筛查胎儿中枢神经系统（CNS）畸形的价值进行了分析。研究对象选取2016年1月~2019年2月本院收治的疑似胎儿CNS畸形的孕妇196例,所有孕妇均给予产前超声、MRI检查,以产后结果为对照,分析产前超声、MRI及二者联合对胎儿CNS畸形的筛查价值。结果显示,产后胎儿CNS畸形84例（42.86%）;在筛查胎儿CNS畸形方面,产前超声敏感度、特异度、准确度分别为80.95%（68/84）、76.79%（86/112）、78.57%（154/196）,产前MRI分别为88.10%（74/84）、82.14%（92/112）、84.69%（166/196）,产前超声联合MRI分别为97.62%（82/84）、94.64%（106/112）、95.92%（188/196）,产前超声联合MRI明显优于产前超声、MRI,差异有统计学意义（P<0.05）。产前超声与MRI比较,差异无统计学意义（P>0.05）。本文证实了产前超声、MRI对胎儿CNS畸形具有良好的筛查价值,且二者联合的筛查价值更高。     

Synthesis of ZSM-5 aggregates by a seed-induced method and catalytic performance in methanol-to-gasoline conversion

A seed-induced method was applied to synthesize a series of ZSM-5 aggregates using silicalite-1 (S-1) as seeds. The samples were characterized by several techniques and studied in the methanol-to-gasoline (MTG) conversion reaction in a continuous fixed-bed reactor. The results showed that the molar ratios of Na₂O/SiO₂ and H₂O/SiO₂ in the precursors had great effects on the physicochemical and catalytic properties. The ZSM-5 aggregates with the highest crystallinity, external surface areas, micropore volumes, mesopore volumes and small primary crystal and aggregate sizes, obtained with the molar composition of 0.12Na₂O–1SiO₂–0.02Al₂O₃–25H₂O-0.01Seed in the precursor, exhibited the highest stability.     

Decomposition of N2O on Rh-loaded zeolites

N₂O was decomposed over Rh supported on NaY zeolite and ZSM5. With low Rh-loading (≤0.1 wt.%) the activity of Rh was much higher than that supported on SiO₂ and CeO₂. On the contrary, the activity of Rh-loaded zeolites (0.1 wt.%) was not so high or even lower than that on SiO₂ for the oxidation of toluene, which has a larger molecular size than N₂O. Thus the Rh present inside the zeolite cavity was especially effective in the decomposition of N₂O.     

Zwei Formen (A- und B-Typ) von Pr2Te[SiO4]

Two Types (A and B) of Pr₂Te[SiO₄] Two forms of praseodymium(III) telluride ortho-silicate (Pr₂Te[SiO₄]) are obtained as light green, transparent single crystals (A type: bricks, B type: needles, both unsensitive to hydrolysis) from a CsCl melt by reacting Pr, TeO₂ and SiO₂ in stoichiometric ratios (950 °C, 10 d) in evacuated silica tubes. A-Pr₂Te[SiO₄] crystallizes orthorhombically (Pbcm; a = 633.70(3), b = 724.42(4), c = 1125.13(8) pm; Z = 4) with alternatingly arranged monolayers {(Pr2)Te}⁺ and {(Pr1)[SiO₄]}^– parallel (001). Pr1 exhibits a coordination number of nine (6 O and 3 Te) while Pr2 has ten next neighbours (6 O and 4 Te), in which all the oxygen atoms are components of discrete ortho-silicate tetrahedra ([SiO₄]^4–), as also is the case in the B-type structure. The telluride anions show coordination numbers of seven (3 Pr1 and 4 Pr2). B-Pr₂Te[SiO₄] crystallizes monoclinically (P2₁/c; a = 989.90(7), b = 648.03(4), c = 870.68(6) pm, β = 94.307(8)°; Z = 4) with along [100] alternatingly sheethed double layers [{(Pr1)Te}₂]²⁺ and [{(Pr2)[SiO₄]}₂]^2–. This results in coordination numbers of eight (4 O and 4 Te) for Pr1, nine plus one (8 O and 1 + 1 Te) for Pr2, and five plus one (4 Pr1 and 1 + 1 Pr2) for Te. The almost 8% higher density of Pr₂Te[SiO₄] in the A-type structure (D_x = 6.45 g/cm³) compared to that of B-type Pr₂Te[SiO₄] (D_x = 5.98 g/cm³) is quite remarkable.     

Preparation of ZSM‐5 Coated on Monolithic Interconnected Macroporous Al2O3 Using Cheap n‐Butylamine as Template

Using cheap n‐butylamine as template, ZSM‐5 zeolites have been successfully synthesized and coated on monolithic interconnected macroporous Al₂O₃ by the secondary growth method. The use of cheap n‐butylamine could significantly reduce the synthesis cost. Hierarchical monolithic ZSM‐5 zeolites were prepared from synthetic mixtures with different H₂O/Na₂O or SiO₂/Al₂O₃ ratio. The synthesized samples were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR) and N₂ adsorption‐desorption. The results show that the hierarchical monolithic zeolites were obtained with cheap n‐butylamine template as template. During the hydrothermal reaction process, the morphology of the micrometer‐sized support was well maintained. The irregular crystals were formed in a wide range of the H₂O/Na₂O or SiO₂/Al₂O₃ ratio of synthetic mixtures and coated on monolithic Al₂O₃. The relative crystallinity of the zeolites was highest at H₂O/Na₂O=250 or SiO₂/Al₂O₃=160. This type of composites exhibited hierarchical porous structures and relatively high specific surface areas.     

Preparation of CuFe2O4/SiO2 nanocomposite starting from Cu(II)–Fe(III) carboxylates embedded in hybrid silica gels

Nanocomposites of the type 30 % CuFe₂O₄/70 % SiO₂ were synthesized using the modified sol–gel method starting from tetraethylorthosilicate, metal nitrates (Fe(NO₃)₃·9H₂O, Cu(NO₃)₂·3H₂O) and the diol: 1,3-propane diol. The obtained hybrid gel, which contains within the pores, the metal nitrates and diol, was thermally treated at 140 °C, when the redox reaction between metal nitrates and 1,3-propane diol takes place forming Cu(II)–Fe(III) carboxylate compounds of malonate type. The thermal decomposition of the carboxylates within the gels pores, at ~300 °C, leads to simple or mixed metal oxides, uniformly distributed within the amorphous silica matrix. The spinel system CuFe₂O₄/SiO₂ was obtained starting with 700 °C. The evolution of the spinel phase with the annealing temperature was investigated and resulted that at 1,000 °C, the matrix crystallizes into cristobalite and quartz. The formation of bulk CuFe₂O₄, starting from the same type of Cu(II)–Fe(III) carboxylate compounds was also investigated. A comparison between the thermal evolution of bulk CuFe₂O₄ and CuFe₂O₄/SiO₂ starting from Cu(II)–Fe(III) carboxylate compounds was made. The magnetic behavior of the ferrite nanocrystallites depending on the annealing temperature was also investigated.     

超临界流体干燥法制备纳米TiO2-SnO2-SiO2复合光催化剂及其光催化性能研究

半导体多相光催化法作为一种污染治理新技术越来越受到人们的重视,在所使用的半导体光催化剂中,TiO2以无毒,催化活性高,价廉,无污染等特点,成为最具有前途的绿色环保型催化剂之一[1],但其自身具有局限性,如禁带宽度大,需在近紫外光下才能激发产生电子空穴对,对太阳光的利用率仅     

SiO2/ZnO复合纳米粒子的制备及表征

采用双注控制沉积法(Controlled Double-Jet Precipitation,CDJP)将反应物添加到含有SiO₂的溶液中,通过直接的表面反应来制备单分散的SiO₂/ZnO复合纳米粒子,并对其进行了表征。透射电镜(TEM)观察表明,SiO₂表面有一层ZnO纳米颗粒或薄层。对复合纳米粒子SiO₂/ZnO进行X射线衍射(XRD)分析,复合颗粒的衍射峰与单独的氧化锌的衍射峰完全一致。能量弥散X射线法(EDX)分析表明,复合颗粒中含有Zn、Si、O元素。荧光光谱表明有ZnO的吸收峰。     

The crystal structure of new quantum memory‐storage material Sc1.368Y0.632SiO5

Monoisotopic scandium yttrium oxyorthosilicate crystals as a material for quantum memory storage with high optical quality were grown by the Czochralski method. This material, of composition Sc_1.368Y_0.632SiO₅, is characterized by congruent melting and a melting point 60 K below the temperature for the ideal solid‐solution series Y₂SiO₅–Sc₂SiO₅. The structure of the crystals was refined on the basis of high‐quality single‐crystal X‐ray diffraction data. Sc_1.368Y_0.632SiO₅ belongs to B‐type RE₂SiO₅ (space group C2/c). Scandium and yttrium cations are distributed among two 8f sites with coordination numbers 7 and 6 for which the occupancy parameters ratios Sc:Y and average bond lengths are, respectively, 0.473:0.527 and RE1—O = 2.305 (2) Å, and 0.895:0.105 and RE2—O = 2.143 (2) Å. It is shown that the character of the occupancy of the positions of the cations with coordination numbers (CN) 6 and 7 for these solid solutions can be approximated by a polynomial dependence, the magnitude of the coefficients of which depends on the difference in the ionic radii of the cations. A preliminary electron paramagnetic resonance (EPR) study shows that activator ions with a large ionic radius at a concentration less than 0.1% occupy a position with CN = 7.     

Thermal decomposition and sensitivities of RDX/SiO<Subscript>2</Subscript> nanocomposite prepared by an improved supercritical SEDS method

A kind of classic nanocomposite, in which nano-RDX (~60 nm) was embedded inside as the core and nano-SiO₂ (~6 nm) compactly coated on its surface, was successfully prepared by an improved supercritical SEDS method. Therein, a special design of the nozzle made the fabrication realized. Analyses, such as SEM, TEM, XRD, IR, and XPS, were employed to investigate the micron morphology and structure of the nanocomposite. Thermal analysis was also conducted, and the DSC traces collected at different heating rate were obtained. Using these DSC data, we calculated the kinetic and thermodynamic parameters for thermal decomposition of raw RDX, RDX/SiO₂ nanocomposite, and a simple mixture ([RDX + SiO₂]), by which the characteristic of the decomposition was depicted clearly. It was confirmed that for different samples, the parameters such as E _K, ΔH ^≠, and T _b changed remarkably. Meanwhile, the decomposition products were also probed with DSC-IR analysis. The results indicated that the main products for both raw RDX and RDX/SiO₂ were CO₂, N₂O, and NO₂. However, the detected signal intensity of NO₂ for RDX/SiO₂ was much stronger than that for raw RDX. In addition, testing of mechanical sensitivity disclosed that RDX/SiO₂ was far more insensitive than raw RDX, and then the mechanism about this was discussed.     

Hydrothermal Synthesis of Silicoaluminophosphate with AEL Structure Using a Residue of Fluorescent Lamps as Starting Material

Silicoaluminophosphate molecular sieves of SAPO-11 type (AEL structure) were synthesized by the hydrothermal method, from the residue of a fluorescent lamp as a source or Si, Al, and P in the presence of water and di-propyamine (DPA) as an organic template. To adjust the P₂O₅/SiO₂ and Si/Al and ratios, specific amounts of silica, alumina, or alumina hydroxide and orthophosphoric acid were added to obtain a gel with molar chemical composition 1.0 Al₂O₃:1.0 P₂O₅:1.2 DPA:0.3 SiO₂:120 H₂O. The syntheses were carried out at a temperature of 473 K at crystallization times of 24, 48, and 72 h. The fluorescent lamp residue and the obtained samples were characterized by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and BET surface area analysis using nitrogen adsorption isotherms. The presence of fluorapatite was detected as the main crystalline phase in the residue, jointly with considered amounts of silica, alumina, and phosphorus in oxide forms. The SAPO-11 prepared using aluminum hydroxide as Al source, P₂O₅/SiO₂ molar ratio of 3.6 and Si/Al ratio of 0.14, at crystallization time of 72 h, achieves a yield of 75% with a surface area of 113 m²/g, showing that the residue from a fluorescent lamp is an alternative source for development of new materials based on Si, Al, and P.     

Comparative evaluation of new Cookson‐type reagents for LC/ESI‐MS/MS assay of 25‐hydroxyvitamin D3 in neonatal blood samples

The screening of vitamin D deficiency in neonatal infants, which is based on the blood 25‐hydroxyvitamin D₃ [25(OH)D₃] quantification, is important for the early detection, diagnosis and health risk assessment of several diseases. In this study, two new Cookson‐type reagents, 4‐(4‐diethylaminophenyl)‐1,2,4‐triazoline‐3,5‐dione (DEAPTAD) and 4‐(6‐quinolyl)‐1,2,4‐triazoline‐3,5‐dione, were designed and synthesized, then compared with the previous reagents, 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) and 4‐(4‐dimethylaminophenyl)‐1,2,4‐triazoline‐3,5‐dione (DAPTAD), in terms of sensitivity and specificity in the assay of 25(OH)D₃ in neonatal blood samples by liquid chromatography/electrospray ionization–tandem mass spectrometry. Among the reagents, DEAPTAD was found to be the most promising. The limit of detection (0.38 fmol on the column) of the DEAPTAD‐derivatized 25(OH)D₃ was 60 and 2 times lower than those of the intact 25(OH)D₃ and the PTAD derivative, respectively. 25(OH)D₃ was more clearly detected in the plasma sample as the DEAPTAD derivative than the DAPTAD derivative owing to the lower background noise. DEAPTAD derivatization was also useful for the separation of 25(OH)D₃ from a potent interfering metabolite, 3‐epi‐25‐hydroxyvitamin D₃. By using DEAPTAD, a trace amount of 25(OH)D₃ in dried blood spots was reproducibly determined without interference from coexisting compounds. Thus, DEAPTAD was proved useful in the measurement of 25(OH)D₃ in neonatal blood samples. Copyright © 2015 John Wiley & Sons, Ltd.     

Rapid determination of amino acids in neonatal blood samples based on derivatization with isobutyl chloroformate followed by solid-phase microextraction and gas chromatography/mass spectrometry

The purpose of this study was to develop a simple, rapid and sensitive analytical method for determination of amino acids in neonatal blood samples. The developed method involves the employment of derivatization and a solid-phase microextraction (SPME) technique together with gas chromatography/mass spectrometry (GC/MS). Amino acids in blood samples were derivatized by a mixture of isobutyl chloroformate, methanol and pyridine, and the N(O,S)-alkoxycarbonyl alkyl esters thus formed were headspace extracted by a SPME fiber. Finally, the extracted analytes on the fiber were desorbed and detected by GC/MS in electron impact (EI) mode. L-Valine, L-leucine, L-isoleucine, L-phenylanaline and L-tyrosine in blood samples were quantitatively analyzed by measurement of the corresponding N(O,S)-alkoxycarbonyl alkyl esters using an external standard method. SPME conditions were optimized, and the method was validated. The method was applied to diagnosis of neonatal phenylkenuria (PKU) and maple syrup urine disease (MSUD) by the analyses of five amino acids in blood samples. The results showed that the proposed method is a potentially powerful tool for simultaneous screening for neonatal PKU and MSUD.     

Antibacterial glass films prepared on metal surfaces by sol–gel method

This paper describes the preparation and characterization of glass films consisting of SiO₂, Li₂O, Na₂O, K₂O or MgO in varying compositions on stainless steel and aluminum substrates by sol–gel method. Silver phosphate or silver incorporated zeolite was also introduced into the sols for obtaining antibacterial effect. The SiO₂/Li₂O/Na₂O system having the composition of 85:5:10 wt% was found as the optimum for obtaining a stable sol and film formation. The films were investigated by scanning electron microscopy (SEM) and electron dispersive analysis by X-ray (EDX), Fourier transformed infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA). Homogenous films having 300 ± 20 nm thicknesses were formed by spin coating and then by curing at 500 °C for 1 h. Obtained films had high adherence to the metal substrates and they were also durable in acidic, basic or NaCl environments. They also presented a powerful antibacterial effect against E. coli.     

Synthesis of Na2WO4-MnxOy supported on SiO2 or La2O3 as fiber catalysts by electrospinning for oxidative coupling of methane

The oxidative coupling of methane (OCM) is an attractive route to convert natural gas directly into value-added chemical products (C₂₊). This work comparatively investigated SiO₂- or La₂O₃-supported Na₂WO₄-Mn_xO_y (denoted as NWM) catalysts in powder and fiber forms. The powder catalysts were prepared using a co-impregnation method and the fiber catalysts were prepared successfully using an electrospinning technique. The NWM/La₂O₃ fiber catalysts were activated at low temperature (500 °C) and had a 4.7% C₂₊ yield, with the maximum C₂₊ yield of 9.6% at 650 °C, while the NWM/SiO₂ fiber catalyst was activated at 650 °C and had a maximum C₂₊ yield of 20.4% at 700 °C. The XPS results in the O 1s region indicated that NWM/La₂O₃ had a lower binding energy than NWM/SiO₂, suggesting that the lattice oxygen species is easily released from the catalyst surface and creates vacancy sites that enhance performance. The stability test of the catalysts indicated that the La₂O₃-containing catalysts had excellent activity and high thermal stability, while the SiO₂-containing catalysts had a higher C₂₊ yield when the prepared catalysts were compared at 700 °C. Considering the same component catalysts, the fiber catalysts achieved higher performance because their heat and mass transfer properties were enhanced.