微量元素影响幼儿智力发育多因素分析

研究了3609名1～岁儿童头发中微量元素与儿童智力发育不全的关系.结果表明,智力发育不全(IQ值55～69)儿童的发Zn为(68.24±16.56)×10-6、Pb为(14.73±8.68)×10-6;高智商(IQ值109～131)儿童的发Zn为(98.62±20.47)×10-6、Pb为(7.92±6.31)×10-6.正常儿童头发中Zn含量[(83.16±19.35)×10-6]显著高于智力发育不全儿童[(80.08±18.47×10)-6,P＜0.05].而正常儿童头发中Pb含量[(12.67±7.48)×10-6则明显低于智力发育不全儿童[(13.25±7.57)×10-6,P＜0.05].正常女童发Zn明显高于智力发育不全儿童的发Zn(P＜0.05).正常女童发Mn、Pb明显低于智力发育不全儿童的发Mn(P＜0.05)、Pb(P＜0.05).正常男童的发Zn、Cu明显高于智力发育不全儿童的发Zn(P＜0.05)、Cu(P＜0.05).正常男童的发Pb明显低于智力发育不全儿童的发Pb(P＜0.05).低锌高铅可能是儿童智力发育不全的重要致病原因.     

1051例儿童头发中微量元素的研究和相关性分析

为探讨儿童头发中 6种元素之间的相关性关系 ,应用电感耦合高频等离子体发射光谱仪(ICP -AES)测定了 6种元素的含量 ,并用SAS或SPSS软件 ,经计算机处理。结果表明 ,1 0 5 1例儿童头发中Zn、Fe、Cu、Ca、Mn和Pb含量分别为 (91 96± 2 0 0 5 )× 1 0 -6,(3 1 3 6± 5 5 2 )× 1 0 -6,(1 1 78± 2 69)× 1 0 -6,(677 3 8± 1 0 8 94)× 1 0 -6,(2 73± 1 0 4)× 1 0 -6和 (1 1 0 1± 3 62 )× 1 0 -6。儿童头发中 ,Zn与Pb含量呈非常显著负相关 ,P <0 0 1 ;Cu与Mn和Pb呈非常显著正相关 ,P <0 0 1 ;Ca与Pb呈非常显著正相关 (P =0 0 0 1 ) ;Mn与Pb呈非常显著正相关 ,P <0 0 1。     

1000例幼儿头发中微量元素含量分析

测定了 1 0 0 0例儿童头发中 6种元素含量。结果表明 ,本组儿童头发中的Zn为 ( 82 1 4±1 9 1 0 )× 1 0 - 6 ,Ca为 ( 5 1 1 5 5± 93 5 5 )× 1 0 - 6 ,Mn为 ( 1 80± 0 86)× 1 0 - 6 ,均低于国内报道的正常儿童发中元素含量低限值 (Zn 87 75× 1 0 - 6 ,Ca 61 3 2 5× 1 0 - 6 ,Mn 2 1 4× 1 0 - 6 )。本组儿童发Pb平均值为 ( 1 2 81± 7 43 )× 1 0 - 6 ,显著高于国内报道的正常儿童发Pb高限值 ( 1 0 43× 1 0 - 6 )。     

父母职业对幼儿头发中微量元素水平的影响

测定了深圳市父母不同职业的 894名 1～ 7岁幼儿头发中的Zn、Cu、Fe、Ca、Mn、Pb的含量。结果表明 ,父母为干部与父母为工人的幼儿头发中的Fe有显著性差异 (P <0 0 5) ,其含量分别为 (2 9 2± 4 9)× 10 -6和 (30 0± 5 6 )× 10 -6;父母为干部与父母为工人的幼儿头发中的Mn有非常显著性差异 (P <0 0 0 1) ,其含量分别为 (1 7± 0 7)× 10 -6和 (1 9± 1 0 )× 10 -6;父母为干部与父母为工人的幼儿头发中的Pb有显著性差异 (P <0 0 5) ,其含量分别为 (12 3±7 6 )× 10 -6和 (13 2± 7 5)× 10 -6。本文还列出了幼儿头发中元素的含量比较图。     

阳江市幼儿头发中微量元素含量分析

测定了阳江市4449名1～7岁儿童头发中6种元素含量.结果表明,该市儿童头发中的 Zn为(82.15±19.00)×10-6 ,Ca为(511.56±93.55)×10-6 ,Mn为(1.81±0.86)×10-6 ,均低于国内报道的正常儿童发中元素含量低限值 Zn 87.75×10-6,Ca 603.25×10-6,Mn 2.14×10-6.该市儿童发 Pb平均值为(12.82±7.43)×10-6,显著高于国内报道的正常儿童发 Pb高限值10.43×10-6.     

糖尿病人头发中的铬、锰、铁与铜含量水平

采用催化极谱方法分析了 98例 (糖尿病人 47例 ,对照组健康人 5 1例 )头发样品中的微量元素铬 (Cr)、锰 (Mn)、铁 (Fe)、铜 (Cu)、锌 (Zn)、硒 (Se)和宏量元素钙 (Ca)、镁 (Mg)含量水平。结果显示 ,糖尿病人头发样品中的Cr( 0 99± 0 75 )× 1 0 - 6 、Mn( 1 3 0± 0 90 )× 1 0 - 6 和Cu( 8 5 0± 1 40 )× 1 0 - 6 分别显著低于对照组头发样品中的Cr( 1 5 5± 0 97)× 1 0 - 6 、Mn( 2 3 0± 1 60 )×1 0 - 6 和Cu( 1 0 40± 2 90 )× 1 0 - 6 ,Cr、Mn、Cu的显著性水平分别为P =0 0 0 1 ,P <0 0 0 1和P <0 0 0 1。而糖尿病人头发样品中的Fe( 1 9 0 0± 9 0 0 )× 1 0 - 6 ,则显著高于对照组头发样品中的Fe( 1 6 0 0± 8 0 0 )× 1 0 - 6 ,其显著性水平P为 0 0 2 3。但糖尿病人与健康人头发样品中的Zn、Se、Ca和Mg含量水平之间的差别并不显著。这些结果与其他一些研究所得的结论基本一致。     

1007例2～4个月婴儿头发微量元素测定和相关性分析

为探讨 2～ 4个月婴儿头发微量元素的含量和相关性 ,用电感耦合高频等离子体发射光谱法测定了广州市 1 0 0 7例 2～ 4个月健康婴儿的头发中Zn、Fe、Cu、Ca、Mn、Pb 6种元素的含量 ,并用SPSS统计软件包进行了数据处理和相关性分析。结果表明 ,2～ 4个月男女婴儿微量元素以低Zn最为明显 ,分别是 3 3 8%和 3 5 4% ,无性别的差异 (P >0 0 5 ) ;其次是低Cu、Ca、Mn,存在性别的差异 (P <0 0 5 ) ;高Pb分别是 3 5 7%和 2 4 6% ,有性别的差异 ,男婴高Pb比女婴严重(P <0 0 5 )。Fe与Zn、Cu与Ca、Mn与Zn有正相关性 (P <0 0 5 ) ;Pb与其它微量元素含量不存在相关性 (P >0 0 5 )。提示 :广州市 2～ 4个月婴儿存在不同程度的微量元素缺乏 ,母婴均应注意均衡饮食 ,避免铅暴露     

幼儿头发中锌与铅含量相关性分析研究

测定了 5 2 0例幼儿头发中锌 (Zn)和铅 (Pb)含量 ,分别为 ( 97 5 4± 2 8 1 9)× 1 0 - 6、( 1 5 2 2± 5 0 2 )× 1 0 - 6。相关分析表明 ,男女幼儿头发中Zn与Pb含量均存在着非常显著的负相关关系 ,P <0 0 0 1。这两种元素含量在男女幼儿之间没有显著差异。     

幼儿头发中微量元素含量相关性研究

为探讨儿童头发中微量元素是否有协同或拮抗作用,测定了646名1－3岁和3803名4－7岁儿童头发中的Zn,Fe,Cu,Ca,Mn和Pb含量,并研究了各元素间的相互关系,结果表明：1－3岁幼儿头发中Zn,Fe,Cu,Ca,Mn和Pb各元素间均呈正相关,4－7岁儿童的发锌含量与发铅含量呈非常显著负相关（P值均＜0．001）,其它各元素间均呈正相关。     

中药驱铅对儿童血微量元素影响的研究

为探讨中药驱铅对儿童血Pb及微量元素Zn、Cu、Fe、Ca、Mn水平的影响 ,检测了 68例儿童铅中毒患儿服用中药驱铅前后的血Pb及微量元素Zn、Cu、Fe、Ca、Mn水平。结果显示 ,服药后患儿的血Pb明显低于服药前 ,差异有非常显著性 (P <0 0 1 ) ;血Zn水平明显高于服药前 ,差异有显著性 (P <0 0 5 ) ;铅中毒程度越轻 ,驱铅效果越明显 (P <0 0 1 ) ;血微量元素Fe、Cu、Ca、Mn水平无明显差异 (P >0 0 5 )。提示中药对儿童早期铅中毒的驱铅效果好 ,不存在微量元素失衡     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.