原卟啉IX二钠盐的低能铁离子束辐照产物对实验性小鼠再生障碍性贫血的疗效初步研究

利用 110 ke V Fe+ 离子注入原卟啉 IX二钠盐薄膜 ,动物实验和细胞学观察等表明辐照混合产物对于治疗 6 0 Coγ射线所致实验性小鼠再生障碍性贫血具有一定的疗效 ,且无明显的毒副作用 ,有望从中筛选治疗再生障碍性贫血的新药或其先导化合物

湖泊生态系统铁同位素与硫同位素地球化学研究--以红枫湖、阿哈湖为例

湖泊生态系统是陆地水体生态系统的重要组成部分。随着社会经济的不断发展，各种人为因素对湖泊生态系统的影响日益突出，打破了其自然演变规律，诸如 “二次污染”、水体富营养化、重金属污染等环境问题接踵而来。而铁是水生生态系统初级生产力所必需的重要微量营养元素之一，在一定的条件下可以控制和影响浮游藻类的生长速度和种类；而且，铁的氧化还原敏感性很强，其价态的改变往往会影响其它相关重金属的迁移和转化。因此，湖泊生态系统中铁的生物地球化学循环研究具有非常重要的意义。近年来的研究显示，铁同位素分析技术可以用于各种生物作用和非生物作用过程的研究，在海洋和河流生态系统中已有广泛的应用，而对湖泊生态系统的研究则鲜见报导。乌江流域中等富营养化的湖泊――红枫湖和贵阳西南郊矿化程度较高的湖泊――阿哈湖是研究湖泊生态系统中铁生物地球化学循环的理想场所。本文选取这两个性质不同的湖泊为研究对象，运用硫同位素、铁同位素及重金属和营养盐等地球化学方法手段，对两湖流域内硫酸盐的来源、硫同位素的季节和剖面变化特征、铁的来源及铁同位素组成的季节和剖面变化特征及其控制和影响因素等进行了研究和探讨，进一步完善了铁同位素分馏机理，为深化理解和研究湖泊生态系统中铁和硫的生物地球化学循环提供一定的科学依据。论文所获的主要认识总结如下： 两湖流域内湖水与河水的硫酸盐硫同位素地球化学 （1）阿哈湖流域和红枫湖流域水体的硫酸盐浓度和δ34S值均有较宽的分布范围。各入湖支流中，受煤矿废水或煤矸石淋溶液污染的河水的δ34S值相对较低（-8.10‰～-14.92‰），而受生活污水影响严重的河水则具有相对较高的δ34S值（-5.68‰～+0.88‰）。相比而言，阿哈湖流域水体纳入了大量的煤矿废水和煤矸石淋溶液，硫污染程度较红枫湖流域更为严重。因此，阿哈湖湖水具有相对较高的硫酸根浓度（平均为2.30 mmol.L-1）和相对较低的δ34S值（平均为-8.10‰），而红枫湖则具有相对较低的硫酸根浓度（平均为0.96 mmol.L-1）和相对较高的δ34S值（平均为-6.80‰）。 （2）阿哈湖湖水中的硫酸盐主要受煤矿废水、煤矸石淋溶液以及雨水等的控制；红枫湖湖水的硫酸盐主要来源于煤中黄铁矿的氧化和雨水输入，土壤硫化物的氧化和蒸发岩的溶解对湖水硫酸盐硫同位素组成的贡献较小。相比之下，雨水对红枫湖湖水硫同位素的影响更为明显。 （3）红枫湖和阿哈湖湖水的硫酸盐的δ34S值均具有明显的剖面变化特征，而且两湖的变化趋势相似，总体表现为，夏秋季节表层湖水和底层湖水的δ34S值相对较高，而冬春季节湖水剖面上下几乎没有变化。湖水硫酸盐浓度也呈现类似的变化特征，这主要与季节性厌氧湖泊夏季分层冬季混和的典型特点有关。夏季湖水分层期间，大量降雨在湖泊表层的滞留使得δ34S值升高而硫酸盐浓度降低，湖泊底部水层中硫酸盐细菌的还原作用使得底层湖水的硫酸盐浓度降低，而δ34S值升高。 两湖流域内铁同位素地球化学 （1）阿哈湖流域各类样品的δ56Fe值分布在-2.03‰～+0.12‰之间，分布范围较宽。其中湖水悬浮颗粒物的δ56Fe值在-1.36‰～-0.03‰之间，整体相对偏负。湖周各支流河水悬浮颗粒物的δ56Fe值在-0.88‰～+0.07‰之间，也相对富集轻的铁同位素；湖底沉积物和孔隙水的δ56Fe值的分布范围分别为-1.75‰～-0.59‰和-2.03‰～+0.12‰；大气颗粒物和浮游藻类的δ56Fe值分别为+0.06±0.02‰和+0.08‰。与阿哈湖相比，红枫湖流域各类样品的δ56Fe值的分布范围相对较窄，在-0.92‰～+0.36‰之间。湖水悬浮颗粒物的δ56Fe值在-0.85‰～+0.14‰之间，河水悬浮颗粒物的铁同位素组成变化范围为-0.89‰～+0.10‰，二者的变化范围相似。红枫湖沉积物的δ56Fe值在-0.18‰～+0.08‰之间，明显比阿哈湖沉积物的铁同位素组成偏正；而对应孔隙水的铁同位素组成的变化范围为-0.59‰～-0.24‰，均要比对应沉积物的铁同位素值要低。藻类和鲫鱼鱼肉的δ56Fe值分别为+0.36‰和-0.92‰。 （2）通过对两湖研究区湖水悬浮颗粒物与各输入端员环境样品的铁同位素值的研究表明，湖水悬浮颗粒物的δ56Fe值不仅受各输入端员的控制和影响，湖泊内部相关的生物地球化学过程也对湖水悬浮颗粒物的铁同位素组成变化产生了重要影响。两湖研究区内湖水悬浮颗粒物的铁同位素组成均存在季节变化特征，但受湖泊自身特点的影响，主要控制因素方面存在一定差异。夏季阿哈湖湖水悬浮颗粒物的铁同位素值变幅较大，其变化主要表现在表层和底层。表层因受陆源输入的有机结合态铁的影响而具有较负的δ56Fe值，而大气沉降颗粒物和湖泊表层的浮游藻类的影响并不显著。夏季湖水分层期间，“Ferrous Wheel”铁循环对于界面附近铁同位素的重分配起到了主要的控制和影响作用，湖水悬浮颗粒物的铁同位素值在氧化－还原界面附近达到了极负值。水－沉积物界面附近滞水层中亚铁类硫化物的生成可能也是水－沉积物界面附近水层内颗粒物的δ56Fe值偏负的原因之一。而冬季湖水混和时期，阿哈湖湖水剖面悬浮颗粒物的δ56Fe值的变幅明显减小。与阿哈湖不同，藻类的吸附作用可能在夏季红枫湖上层水体中占有主导地位，其湖水悬浮颗粒物的铁同位素组成随叶绿素水平的降低而逐渐降低。下层湖水悬浮颗粒物的铁同位素组成变化也受“Ferrous Wheel”铁循环的影响，在红枫湖后五剖面 20m 处达到-0.18‰，大坝剖面底层约为-0.46‰，其变幅没有阿哈湖悬浮颗粒物的δ56Fe值大，可能是受到了湖水中大量有机物质的影响。冬季红枫湖后五剖面的变化趋势与夏季相似，上层和下层水体悬浮颗粒物分别受不同影响因素的控制。上层水体悬浮颗粒物的铁同位素变化不明显，与Fe、Al、Mn、Zn、Co等元素的含量呈现良好的正相关关系；而底层水体悬浮颗粒物的δ56Fe值变幅比夏季要大，HW采样点20m处可达-0.85‰，与Fe、Al、Zn、Co等呈现良好的负相关关系，具体影响因素还有待于进一步研究。

长江口水体混合过程中的水/粒作用地球化学——微量元素及同位素地球化学研究

近几年来，随着水体地球化学研究的逐步深入，人们发现表生水体中许多微量元素利同位素的水体地球化学行为都与水体颗粒物的行为密切相关，水／粒相互作用过程越来越引起研究者的关注。河口是连接河流与海洋两大不同性质水体的过渡地带，其水体的理化性质及化学组成在短时内会发生显著变化，使得河口环境成为研究表生水体水／粒相互作用过程的优势场所。本文首先对稀土和重金属元素以及锶同位素等化学组分在世界河口水体混合过程中的地球化学行为进行了综述。并在综述和调研的基础上，选择世界大河之一的长江口作为研究区域，通过对水体溶解相、酸溶相、和颗粒物中稀土和重金属元素以及水体锶同位素地球化学的研究，系统了解了长江口表层水体中微量元素和同位素的迁移转化规律，并对发生在河口区的水与颗粒物以及水与沉积物的相互作用过程进行了分析，并得出以下初步结论：1．在长江口，表层水体的混合不是以均匀方式进行的，盐度及主离子浓度在空间剖面上显示非连续性变化。这是由于长江口属于潮汐分汊河口，儿股径流相互穿插所致。但在盐度剖面上，主离子浓度都随盐度增加而线性变化，显示明显的化学保守性。2．长江口水体颗粒物的含量和pH值都比较高，使得溶解态物质的迁移转化规律相对特殊，尤其是水／粒相互作用过程比较强烈。3.长江及长江口水体的~(87)Sr／~(86)Sr比值(0.7105)相对较低，而Sr元素浓度(约150ppb)相对较高。Sr及~(87)Sr／~(86)Sr在长江口水体混合过程中显示保守行为，基本不受水/粒相互作用及其它地球化学过程的影响，只与水体端员的化学组成有关，所以锶同位素是河口研究中确定水体端员的良好指标。4.本文首次测定了长江口表层水体中溶解态REE的浓度。利世界大多数河口相比，长江口溶解态REE的浓度相对较低，仅为0.1～10ppt左右，比其它河口低了近10到100倍。溶解态REE在长江门盐度剖面上的分布规律也比较特殊，显示了自低盐度向高盐度的整体升高趋势，而不是通常的随盐度降低趋势。5.溶解态重金属元素Fe、Co、Ni、Cu、Pb、Zn、Cd等在长江口表层水体混合过程中显示了各不相同的地球化学行为。受胶体絮凝过程的影响，溶解态Fe利Zn的浓度在河口低盐度区显著降低；溶解态Ni和Cu则显示住低盐度区的强烈解吸过程；Co和Pb的行为主要受水体颗粒物吸附作出的控制；溶解态Cd显示随盐度增加的全过程解吸行为。6．本文对江口表层水体中酸溶态利颗粒态微量元素的浓度也进行了测定。结果显示，酸溶态微量元素的行为主要受水体颗粒物行为的控制，但在一定程度上又受到盐度等水化学因素的影响，所以用酸溶态微量元素的行为讨论水/粒相互作用过程比颗粒物全样更为有效。颗粒态微量元素在水体混合过程中的行为相对惰性，除受粒度效应的影响外，基本不受其它物化参数及水／粒相互作用过程的影响，只与其物质来源有关。7．在江口表层水体中，发生着广泛的水／粒相互作用以及水与沉积物相互作用过程。住河口低盐度区以胶体絮凝作用为主，但同时又因离子交换反应而使某些元素(Cu和Ni)发生解吸过程。在河口中高盐度区广泛发生有沉积物再悬浮和颗粒物解吸及解聚过程，从而造成酸溶态及部分溶解态微量元素浓度的升高。8．水／粒相互作用过程明显影响到微量元素长江的入海通量，对解释东中国海及西太平洋的微量元素及同位素地球化学也有比较重要的意义。

Realizing a high magnetic moment in Gd/Cr/FeCo: The role of the rare earth

The search for materials or systems exhibiting a high magnetic saturation has been of longstanding importance. It has been suggested that increased saturation could be achieved by coupling a transition metal via a spacer to a rare earth. We report Gd/Cr/Fe₇₀Co₃₀ multilayer stacks and find reduced yet modulating magnetic moment as a function of Cr thickness. Through a micro structural analysis the lowered moment is indicated by the nucleation of the ultrathin Gd films into an fcc phase. We discuss the possible solution in terms of quasi-perfect lattice match seed material to promote growth of hcp Gd.

Desenvolupament i caracterització d'aliatges de base ferro produïts per aliatge mecànic i solidificació ràpida

L'objectiu general d'aquest treball és l'obtenció de nous materials nanoestructurats magnètics tous produïts mitjançant la tècnica de l'aliatge mecànic. Forma part d'un projecte més ampli de desenvolupament d'aquests tipus d'aliatges amb altres tècniques, com les de solidificació ràpida, i la seva posterior molturació i compactació per a l'aplicació a la indústria pulverimetal·lúrgica. Aquests materials tindran una estructura amorfa i/o nanocristal·lina que comportarà una millora de les seves propietats magnètiques. Els objectius particulars d'aquest treball són: - Síntesi d'aliatges de Fe-Ni-Zr-B-(Co), Fe-Nb-B-(Cu), i Fe-Ni-Nb-B mitjançant aliatge mecànic. Es parteix de precursors cristal·lins i es tracta d'obtenir un aliatge bàsicament nanocristal·lí. En concret, es pretén obtenir aliatges: ·Amb una alta estabilitat tèrmica que afavoreixi posteriors estudis de consolidació. ·Amb la presència de nanocristalls de reduïdes dimensions o d'una fase amorfa que permeti posteriors tractaments tèrmics per a produir aliatges de nanoestructura controlada. -Comparació entre les mostres produïdes per aliatge mecànic amb diferents micromolins de les mostres Fe-Nb-B. Els micromolins utilitzats són un P7 i un SPEX 8000 -Estudi de la influència dels diferents precursors i de la quantitat relativa dels mateixos que s'ha utilitzat per a cada mostra, concretament: ·La substitució en els aliatges de Fe-Nb-B de Fe per Ni, tot i que interessa que els aliatges tinguin una alta quantitat de ferro perquè tingui millors propietats magnètiques. ·La substitució en els aliatges de Fe-Ni-Zr-B de Fe per Co. ·La inclusió de Cu en les mostres Fe-Nb-B ·La comparació entre els aliatges amb Nb i amb Ni-Zr -Modelització del comportament termodinàmic d'equilibri dels compostos Fe-Nb-B, mitjançant software de minimització de l'energia lliure dels diferents elements. S'han utilitzat una sèrie de tècniques analítiques per a avaluar l'estabilitat tèrmica i realitzar la caracterització estructural dels aliatges obtinguts. Anàlisi de l'estabilitat tèrmica mitjançant anàlisi calorimètrica diferencial (DSC) i termogravimetria (TG). També s'analitzarà la cinètica de cristal·lització mitjançant tractaments isotèrmics i dinàmics. -Anàlisi morfològic de les diferents mostres per microscòpia electrònica de rastreig (SEM) i caracterització estructural de les diferents fases presents i de les diferents microestructures obtingudes mitjançant difracció de raigs X XRD)i microscòpia electrònica de transmissió(TEM). S'identificaran les diferents fases presents i es calcularan els diferents paràmetres de cel·la, així com la dimensió de les microestructures. L'anàlisi microestructural es complementarà amb algunes mesures 'espectroscòpia Mössbauer de transmissió (TMS)

Self-assembled biomimetic [2Fe2S]-hydrogenase-based photocatalyst for molecular hydrogen evolution

The large-scale production of clean energy is one of the major challenges society is currently facing. Molecular hydrogen is envisaged as a key green fuel for the future, but it becomes a sustainable alternative for classical fuels only if it is also produced in a clean fashion. Here, we report a supramolecular biomimetic approach to form a catalyst that produces molecular hydrogen using light as the energy source. It is composed of an assembly of chromophores to a bis(thiolate)-bridged diiron ([2Fe2S]) based hydrogenase catalyst. The supramolecular building block approach introduced in this article enabled the easy formation of a series of complexes, which are all thoroughly characterized, revealing that the photoactivity of the catalyst assembly strongly depends on its nature. The active species, formed from different complexes, appears to be the [Fe-2(mu-pdt)(CO)(4){PPh2(4-py)}(2)] (3) with 2 different types of porphyrins (5a and 5b) coordinated to it. The modular supramolecular approach was important in this study as with a limited number of building blocks several different complexes were generated.

Thermal behaviour of malonic acid, sodium malonate and its compounds with some bivalent transition metal ions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal behaviour of succinic acid, sodium succinate and its compounds with some bivalent transition metal ions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal behaviour of mandelic acid, sodium mandelate and its compounds with some bivalent transition metal ions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reação de redução de oxigênio sobre perovskitas La1-xSrxFeyCo1-yO3-δ, para células a combustível de óxido sólido (SOFC)

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Hidrogeoquímica do aquífero Bauru na área urbana do município de Marília (SP)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chemical composition of ferromanganese nodules from the Black Sea

Ferruginate shells and tubular worm burrows from the oxygenated zone of the Black Sea (Kalamit Bay and Danube River mouth) are studied by transmission and scanning electron microscopy combined with analyses of elemental composition. Iron and manganese oxyhydroxide nodules considered here are enriched in phosphorus. They contain variable amounts of terrigenous and biogenic material derived from host sediments. Oxyhydroxides are mainly characterized by colloform structure, whereas globular and crystalline structures are less common. The dominating iron phase is represented by ferroxyhite and protoferroxyhite, whereas the manganese phase is composed of Fe-free vernadite. Concentrations of Mn, As, and Mo are 12-18 times higher relative to sediments, while concentrations of Fe, P, Ni, and Co increase 5-7 times during nodule formation.

Speciation of metals in bottom sediments from the south Kara Sea and Ob and Yenisei estuarine zones

Speciation of Fe, Mn, Zn, Cu, Co, Ni, Cr, Pb, and Cd was studied in 52 samples of bottom sediments collected during Cruise 49 of the R/V "Dmitry Mendeleev" to the estuaries of the Ob and Yenisei rivers and to the southwest Kara Sea. Immediately after sampling the samples were subjected to on-board consecutive extraction to separate metal species according to their modes of occurrence in the sediments: (1) adsorbed, (2) amorphous Fe-Mn hydroxides and related metals, (3) organic + sulfide, and (4) residual, or lithogenic. Atomic absorption spectroscopy of the extracts was carried out at a stationary laboratory. Distribution of Fe, Zn, Cu, Co, Ni, Cr, Pb, and Cd species is characterized by predominance of lithogenic or geochemically inert modes (70-95% of bulk contents), in which the metals are bound in terrigenous and clastic mineral particles and organic detritus. About half of total Mn amount and 15-30% of Zn and Cu are contained in geochemically mobile modes. Spatiotemporal variations in proportions of the metal species in the surface layer of sediments along sub-meridional sections and through vertical sections of bottom sediment cores testify that Mn and, to a lesser extent, Cu are the most sensitive to changes in sedimentation environment. The role of their geochemically mobile species notably increases under reducing conditions.

(Table 1) Zoobenthos from the gas-hydrate seep area near the Paramushir Island and its chemical composition

Distributions of Mn, Fe, Cu, Cd, Cr, Co and Ni in sea water are investigated (42 samples, dissolved and particulate forms) in the vicinity of the underwater gas vent field on the northwestern slope of the Paramushir Island. While regular background distributions of the elements occur in the shore zone, there is a column of elevated concentrations of particulate matter, particulate Mn, and dissolved Mn, Fe, Cu, Cd, Cr, Co and Ni that coincides with location of the gas plume. This column can be traced as high as 780 m above the bottom. High metal concentrations in water of the plume are attributable to physico-chemical concentration at the phase interface; the source of elevated mineral concentrations is obviously flux of dissolved minerals from interstitial waters, which extends to considerable distances in vertical direction.

(Table 2) Chemical composition of surface sediments from stations of Cruise 11A of R/V Akademik Mstislav Keldysh

Distributions of Mn, Fe, Cu, Cd, Cr, Co and Ni in sea water are investigated (42 samples, dissolved and particulate forms) in the vicinity of the underwater gas vent field on the northwestern slope of the Paramushir Island. While regular background distributions of the elements occur in the shore zone, there is a column of elevated concentrations of particulate matter, particulate Mn, and dissolved Mn, Fe, Cu, Cd, Cr, Co and Ni that coincides with location of the gas plume. This column can be traced as high as 780 m above the bottom. High metal concentrations in water of the plume are attributable to physico-chemical concentration at the phase interface; the source of elevated mineral concentrations is obviously flux of dissolved minerals from interstitial waters, which extends to considerable distances in vertical direction.