2017～2018年宁波市出生儿童13价肺炎球菌结合疫苗接种率分析

目的分析2017～2018年宁波市出生儿童13价肺炎球菌结合疫苗(13-valent pneumococcal conjugate vaccine,PCV13)的接种率。方法收集宁波市"免疫预防管理信息系统"中2017～2018年出生儿童的PCV13接种信息,采用描述性流行病学方法进行统计分析。结果宁波市2017～2018年出生儿童221 921人,接种PCV13有25 124人,≥1剂次接种率为11. 32%,其中至少接种3针PCV13的有19 212人,≥3剂次接种率为8. 66%。25 124名<2岁儿童中,首针疫苗接种年龄≤1、2、3、4和≥5月龄者分别为5 428、11 287、5 556、2 608和245人,分别占21. 60%、44. 93%、22. 11%、10. 38%和0. 98%。不同地区、户籍类型、出生年份儿童PCV13≥1和≥3剂次接种率差异均有统计学意义(P均<0. 001),不同地区、性别、户籍类型、出生年份儿童PCV13首针疫苗接种年龄差异有统计学意义(P均<0. 01)。结论宁波市儿童PCV13接种率处于较低水平,建议将PCV13纳...     

Analysis of sequence distribution in methyl methacrylate-methyl acrylate copolymers by C NMR spectroscopy

Methyl methacrylate (MMA)-methyl acrylate (MA) copolymers, prepared in bulk at 50 °C using AIBN as initiator, were characterized by 150 MHz ¹³C NMR spectroscopy, including use of the Distortionless Enhancement by Polarization Transfer (DEPT) experiment to obtain methylene and methine carbon resonances as subspectra. Dyad, triad, tetrad and partial pentad distributions were measured from the α-methyl, methine and methylene carbon resonances. These were in good agreement with distributions calculated for the copolymers based on monomer feed compositions, conversions and reactivity ratios of 2.60 and 0.27 for methyl methacrylate and methyl acrylate, respectively.     

Classification of vegetable oils by high-resolution <Superscript>13</Superscript>C NMR spectroscopy using chromatographically obtained oil fractions

¹³C NMR spectra of oil fractions obtained chromatographically from 109 vegetable oils were obtained and analyzed to evaluate the potential use of those fractions in the classification of vegetable oils and to compare the results with the NMR analysis of complete oils. The oils included the following: virgin olive oils from different cultivars and regions of Europe and north Africa; “lampante” olive, refined olive, refined olive pomace, hazelnut, rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils; and mixtures of virgin olive oils from different geographical origins. Oils were divided into two sets of samples. The training set (98 samples) was employed to select the variables that resulted in significant discrimination among the different oil classes. By using stepwise discriminant analysis, more than 98% of correct validated assignments were obtained; these results were confirmed when applied to the test set (11 blind samples). Results suggest that the use of oil fractions considerably increases the discriminating power of NMR in the analysis of vegetable oils.     

Studies on copolymers of acrylonitrile with resins of furfuryl alcohol: 1. Preparation and thermal properties

Copolymers of acrylonitrile with a furfuryl alcohol resin have been prepared by a free radical reaction, and have been characterized by n.m.r. and i.r. spectroscopy. Their t.g.a. has been performed in air and in a nitrogen atmosphere, to permit the recognition of a number of stages in the weight loss process. D.s.c., also in air and in nitrogen, has identified a number of exothermic and one endothermic process in the copolymers. Solid state cross-polarization/magic angle spinning ¹³C n.m.r. spectroscopy and i.r. spectroscopy has been used to obtain some insight into the chemistry of the various chemical changes, which in air are completed by combustion and in nitrogen leave a carbon.     

Linking chemical reactivity and protein precipitation to structural characteristics of foliar tannins

Tannins influence ecosystem function by affecting decomposition rates, nutrient cycling, and herbivory. To determine the role of tannins in ecological processes, it is important to quantify their abundance and understand how structural properties affect reactivity. In this study, purified tannins from the foliage of nine species growing in the pygmy forest of the northern California coast were examined for chemical reactivity, protein precipitation capacity (PPC), and structural characteristics (¹³C NMR). Reactivity of purified tannins varied among species 1.5-fold for the Folin total phenol assay, and 7-fold and 3-fold, respectively, for the acid butanol and vanillin condensed tannin assays. There was about a 5-fold difference in PPC. Variation in chemical reactivity and PPC can be largely explained by differences in structural characteristics of the tannins determined by ¹³C NMR. In particular, the condensed versus hydrolyzable tannin content, as well as the hydroxylation pattern of the B-ring and stereochemistry at the C-2–C-3 position appear to influence reactivity. Due to the large differences in chemical reactivity among species, it is necessary to use a well-characterized purified tannin from the species of interest to convert assay values to concentrations. Our results suggest that structural characteristics of tannins play an important role in regulating their reactivity in ecological processes.     

Sequence analysis of poly(ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer using H and C NMR

The triad-level sequence analysis of poly(ethylene/1,4-cyclohexanedimethylene terephthalate) copolymer was reported in a solvent system of o-chlorophenol/deuterated chloroform mixture (50/50 v/v) at 80 °C using 600 MHz ¹H NMR. The well-resolved alcoholic CH₂ proton peak of the glycol units was observed, which made the detailed sequence analysis possible. The peaks of the cis- and trans-forms of the 1,4-cyclohexanedimethylene glycol units were split into the triad sequence in the chain and could be assigned by a comparison of the spectra with those of homopolymers and by an additional two-dimensional heteronuclear multiple bond correlation observation. The triad sequence distributions centered on 1,4-cyclohexanedimethylene glycol units were determined, which was independent of the cis- and trans-forms of the units and controlled according to Bernoullian statistics.     

P(MMA-DBMEA)乳液聚合研究

甲基丙烯酸甲酯 ( MMA)在无皂乳化剂条件下 ,加入少量的功能性单体 N,N一二甲基 ,N-丁基 ,N-甲基丙烯酰氧乙基溴化铵 ( DBMEA) ,合成了稳定的 P( MMA-DBMEA)共聚物乳液 .该共聚物乳胶粒呈现单分散分布。同时用 NMR研究了共聚物 ,并对 P( MMA-DBMEA)聚合物13 C进行了全归属。     

Criteria dilemma of phase behavior in ternary blends comprising polystyrene, poly(alpha-methyl styrene), and poly(4-methyl styrene)

A ternary blend system of polystyrene (aPS), poly(α-methyl styrene) (PαMS), and poly(4-methyl styrene) (P4MS) (blends of three styrenic homopolymers of similar molecular structures) was investigated by using differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), scanning electron microscopy (SEM), and solid-state ¹³C cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR). This ternary system of aPS/PαMS/P4MS exhibits a small miscibility loop only at relatively high percentages of PαMS (≥80%), while most of the aPS/PαMS/P4MS compositions exhibit two coexisting aPS/PαMS and aPS/P4MS phases in the immiscibility loop. In the immiscible loop, SEM measurements revealed evidence in contrasting with DSC for criteria of miscibility. DSC characterization revealed a single T_g for most ternary blend compositions; however, SEM graphs apparently indicated sub-micron phase domains, except for several PαMS-rich compositions (>80%). The and techniques using NMR were found to resolve the dilemma between the conventional thermal analysis and microscopy results, and indeed supported that the ternary blends at above 80% PαMS are completely homogeneous on the molecular level. Attempts have been made to resolve the seemingly contradictory interpretations on the complex ternary phase structures and domains from the DSC, and microscopy results.     

Chitin characterization by SEM,FTIR, XRD,and 13C cross polarization/mass angle spinning NMR

The full characterization of chitin obtained from squid, shrimp, prawn, lobsters, and king crab is reported. Elemental analysis, including metals such as Ca, Mg, Zn, Cd, Hg, Cr, Mn, Cu, and Pb, was performed, which is quite relevant because the skeleton composition is slightly different for each species. The morphology was studied by means of TEM and their compositions were determined by energy‐dispersive X‐ray analysis. ¹³C cross polarization/magic angle spinning NMR was applied to determine the chemical shift of all the carbons and the difference between them. Chitin was isolated by using chemical methods, alternating hydrochloric acid and sodium hydroxide. The α‐chitin from shrimp, prawn, lobsters, and king crabs showed two signals at 73.7 and 75.6 ppm. Meanwhile, the β‐chitin from squid exhibited one signal at 75.2 ppm. FTIR studies were used to analyze α‐chitin from shrimp and β‐chitin from squid. The α‐chitin exhibited amide I vibration modes at 1660 and 1627 cm^?1, whereas the β‐chitin showed one band at 1656 cm^?1. X‐ray diffraction showed that α‐chitin is orthorhombic (a = 4.74 Å, b = 18.86 Å, and c = 10.32 Å) and β‐chitin had a monoclinic dihydrated form (a = 4.80 Å, b = 10.40 Å, c = 11.10 Å, and β = 97°). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1876–1885, 2004     

Semiquantitative analysis of thiophenic compounds in light cycle oil (LCO) using C NMR spectroscopy

S-methyltetrafluoroborate salts of the thiophenic compounds (CH₃-S⁺:BF₄⁻) present in LCO petroleum fractions were obtained and analyzed by ¹H and ¹³C NMR spectroscopy. The methylation of the samples was carried out using 99.5% ¹³C enriched methyl iodine, to improve the sensitivity of the technique. The amount of the methylated derivatives was determined by the internal standard method; using dioxane as a reference, 37 sulphur compounds were detected. Among them, benzo[b]thiophene, dibenzo[b,d]thiophene, and several isomers of methyl, dimethyl and trimethyl[b]benzothiophenes were the most abundant. With this research, it was demonstrated that NMR spectroscopy can be used to analyze thiophenic compounds from petroleum medium fractions.