Very low-pressure VLP-CVD growth of high quality gamma-Al2O3 films on silicon by multi-step process

gamma-Al2O3 films were grown on Si (10 0) substrates using the sources of TMA (AI(CH3)(3)) and O-2 by very low-pressure chemical vapor deposition. The effects of temperature control on the crystalline quality, surface morphology, uniformity and dielectricity were investigated. It has been found that the,gamma-Al2O3 film prepared at a temperature of 1000degreesC has a good crystalline quality, but the surface morphology, uniformity and dielectricity were poor due to the etching reaction between 0, and Si substrate in the initial growth stage. However, under a temperature-varied multi-step process the properties Of gamma-Al2O3 film were improved. The films have a mirror-like surface and the dielectricity was superior to that grown under a single-step process. The uniformity of gamma-Al2O3 films for 2-in epi-wafer was <5%, it is better than that disclosed elsewhere. In order to improve the crystalline quality, the gamma-Al2O3 films were annealed for I h in O-2 atmosphere. (C) 2002 Elsevier Science B.V. All rights reserved.

Terahertz pulse generation with LT-GaAs photoconductive antenna

Low-temperature-grown GaAs (LT-GaAs) of 1-um thickness was grown at 250 degrees C on semi-insulating GaAs (001) substrate using EPI GEN-II solid-source MBE system. The sample was then in situ annealed for 10 min at 600 degrees C under As-rich condition. THz emitters were fabricated on this LTGaAs with three different photoconductive dipole antenna gaps of 1-mm, 3-mm, and 5-mm, respectively. The spectral bandwidth of 2.75 THz was obtaind with time domain spectroscopy. It is found that THz emission efficiency is increased with decreasing antenna gap. Two carrier lifetimes, 0.469 ps and 3.759 ps, were obtained with time-resolved transient reflection-type pump-probe spectroscopy.

磷化铟单晶衬底的缺陷控制和高质量表面制备

分析研究了一些缺陷对InP单晶衬底的影响,包括团状结构位错的产生及其对晶格完整性的影响,坑状微缺陷、晶片抛光损伤和残留杂质的清洗腐蚀等.对这些缺陷的形成原因和抑制途径进行了分析.在此基础上获得了"开盒即用(EPI-READY)"、具有良好晶格完整性、表面无损伤的InP单晶衬底抛光片.

Heteroepitaxial growth of novel SOI material Si/gamma-Al2O3/Si

In this paper, we report the fabrication of Si-based double hetero-epitaxial SOI materials Si/gamma-Al2O3/Si. First, single crystalline gamma-Al2O3 (100) insulator films were grown epitaxially on Si(100) by LPCVD, and then, Si(100) epitaxial films were grown on gamma-Al2O3 (100)/Si(100) epi-substrates using a CVD method similar to silicon on sapphire (SOS) epitaxial growth. The Si/gamma-Al2O3 (100)/Si(100) SOI materials are characterized in detail by RHEED, XRD and AES techniques. The results demonstrate that the device-quality novel SOI materials Si/gamma-Al2O3 (100)/Si(100) has been fabricated successfully and can be used for application of MOS device.

Heteroepitaxial growth and annealing of gamma-Al2O3 thin films on silicon

The gamma-Al2O3 films were grown on Si (100) substrates using the sources of TMA (Al (CH3)(3)) and O-2 by very low-pressure chemical vapor deposition (VLP-CVD). It has been found that the gamma-Al2O3 film has a mirror-like surface and the RMS was about 2.5nm. And the orientation relationship was gamma-Al2O3(100)/Si(100). The thickness uniformity of gamma-Al2O3 films for 2-inch epi-wafer was less than 5%. The X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) results show that the crystalline quality of the film was improved after the film was annealed at 1000degreesC in O-2 atmosphere. The high-frequency C-V and leakage current of Al/gamma-Al2O3/Si capacitor were also measured to verify the annealing effect of the film. The results show that the dielectric constant increased from 4 to 7 and the breakdown voltage for 65-nm-thick gamma-Al2O3 film on silicon increases from 17V to 53V.

Electronic and vibrational Raman scattering in resonance with yellow luminescence transitions in GaN on sapphire substrate

We analyze low-temperature Raman and photoluminescence spectra of MBE-grown GaN layers on sapphire. Strong and sharp Raman peaks are observed in the low frequency region. These peaks, which are enhanced by excitation in resonance with yellow luminescence transitions, are attributed to electronic transitions related to shallow donor levels in hexagonal GaN. It is proposed that a low frequency Raman peak at 11.7 meV is caused by a pseudo-local vibration mode related to defects involved in yellow luminescence transitions. The dependence of the photoluminescence spectra on temperature gives additional information about the residual impurities in these GaN layers.

八株海洋微生物次级代谢产物的研究

本论文选取4株胶州湾海洋放线菌和4株条斑紫菜丝状体相关丝状真菌，进行了次级代谢产物的分离纯化与鉴定，共得到78个单体化合物，其中10个为新颖结构。对部分纯化合物进行了抑菌，抗肿瘤活性测试，并对菌株进行了菌种鉴定。具体结果如下： 从胶州湾放线菌M491，M097，M361和M353得到40个单体化合物，其中6个为新颖结构化合物。从M491分离到14个单体化合物，包括2个新结构倍半萜15-hydroxy-T-muurolol (1a)和11,15-dihydroxy-T-muurolol (1b)，2个首次报道的微生物来源的倍半萜T-muurolol (2b)和3α-hydroxy-T-muurolol (2c)，2个新颖结构大环内酯chalcomycin C (7)和chalcomycin D (8)。制备了3-oxo-T-muurolol (2a)单晶体，纠正了前人发表的错误结构。从M353分离得到10个化合物，包括2个新颖倍半萜5-hydroxy-epi-isozizaene (28)和5,14-dihydroxy-isozizaene (30)。自M097和M361分别分离得到12个，4个已知结构化合物。 从健康条斑紫菜丝状体分离得到了12株真菌。从优势附生菌N5分离得到了12个化合物，包括phenylacetic acid (42)，p-hydroxyphenylethyl alcohol (43)和L-β-phenyllactic acid (49)等广谱抗生素和紫菜生长调节剂。 对分离自白斑病条斑紫菜丝状体真菌N27，EF8，GA4进行了次级代谢产物研究，分离得到38个单体化合物。从GA4分离得到了16个化合物，4个为新结构化合物，包括1个酰脲类化合物hualyzin (62)和3个phenalenone族新化合物7-methyl isonorherqueinone (69)，7,8-dimethyl atrovenetin (70)和8-methyl-deoxyherqueinone (73)。从真菌N27和EF8分别分离得到12个和2个已知结构化合物。 采用MTT法，对37株人体肿瘤细胞株活性表明：chalcomycin C (7)和chalcomycin D (8)具有非常强的细胞毒活性，其平均IC50分别为0.027 μg/mL和0.007 μg/mL。7,8-Dimethyl atrovenetin (71)和8-methyl deoxyherqueinone (73)具有中等细胞毒活性，其平均IC50分别为5.1 μg/mL和0.7 μg/mL。 此外，本文首次报道了几个已知化合物的细胞毒活性，分别是chalcomycin （0.015 μg/mL），kalamycin (0.06 µg/mL)，(+)-homononactic acid（1.9 µg/mL），(+)-nonactic acid（2.3 µg/mL），griseoviridin（3.9 µg/mL），cyclo（L-Trp-L-Phe）（3.3 µg/mL），WIN 64821（5.8 µg/mL）和3,5-dihydroxy-2-methyl-4-pyrone（3.3 µg/mL）。 菌种鉴定结果表明：M353归属链霉菌，GA4，N27归属青霉属，EF8归属曲霉属，N5为枝孢霉属。

两种海藻提取物的化学成分和生物活性的研究及其应用

本论文的研究工作由两部分组成，第一部分研究了海带（Laminaria japonica）水提取物中的活性物质，并研究了提取物对蔬菜促生长的影响及其作用机制。第二部分对三列凹顶藻(Laurencia tristicha)乙醇提取物的乙酸乙酯相进行了活性筛选和化学成分研究，并对其中分离得到的单体化合物进行了生物活性筛选。 第一部分主要以中国人工养殖的海带为原料，使用与海藻多糖生产相结合的提取技术并浓缩其中的有效成分。对浓缩提取物进行了蔬菜的农田效果实验，并对作物抗旱性能的增加、作物硝酸盐积累的减少、作物品质的改善、以及作物抵抗病毒病的能力等影响进行了作用机制方面的研究。海藻浓缩提取物进行的农田效果实验表明：作物抗旱型相对含水量RWC值在92%~94%之间；病毒病的防治效果最高可达到91%；作物的品质有明显的改善，最重要的是首次发现海藻提取物有降低蔬菜中硝酸盐的含量（硝酸盐的含量是与有机蔬菜区别的重要指标之一）的作用。该部分研究工作的创新性主要体现在：（1）首次在国内外提出和采用与海藻多糖生产相结合的提取技术。该技术的应用不但减少了提取成本，使工业化生产成为可能,更重要的是使我国的海藻工业生产可能实现高值化和开辟综合利用的新途径。（2）首次发现海藻中的小分子海藻多糖具有和细胞激动素、甜菜碱、植物生长素等活性物质同样的生物活性。 第二部分的研究是在查阅了大量的近20年来国内外有关红藻凹顶藻中化学成分研究的相关文献的基础上，对凹顶藻中的次生代谢产物进行了综述。该论文主要是通过对红藻三列凹顶藻的95%乙醇提取物的乙酸乙酯相进行化学成分分析和生物活性筛选以期能够发现具有药用前景的活性先导化合物。 为了寻找具有生物活性的化合物，我们对采自我国南海硇洲岛海域的红藻三列凹顶藻的95%乙醇提取物的乙酸乙酯相进行了活性筛选。采用MTT法对其在KB细胞株、Bel-7402细胞株、PC-3M细胞株、MCF-7细胞株、Ketr-3细胞株模型上进行了细胞毒活性测试；采用酶模型对其进行了Na+,K+-ATPase的抑制活性测试；采用MTT法对其在犬主动脉血管模型上进行了血管平滑肌细胞增殖抑制活性测试；结果表明，三列凹顶藻的95%乙醇提取物的乙酸乙酯相对Na+,K+-ATPase和犬血管平滑肌细胞增殖具有一定的抑制活性。 利用正相和反相色谱、Sephadex LH-20色谱以及反相HPLC等手段进行分离纯化，从我国南海海域的红藻三列凹顶藻中分离得到33种化学成分，通过波谱学方法（IR、MS、NMR）以及X-ray单晶衍射试验对其化学结构进行了确证，其中化合物L1~L8为新结构化合物，化合物L5为具有新骨架的全新结构化合物，化合物L9~L13为新天然产物，化合物L18和L22系首次从海洋生物中获得，所有化合物均为首次从该属海藻中得到。新化合物L1~L8均为倍半萜类化合物，命名分别为：(1R,3R)-(-)-3-(3-hydroxy-4-methylphenyl)- 1,3-dimethyl–2-methylidene cyclopentanol (L1), (1R,3R)-(-)-3-(4-methylphenyl)-1,3-dimethyl-2-methylidenecyclopentanol (L2)， (1R, 3R)-(-)-3-(2-hydroxy-4-methylphenyl)-1,3-dimethyl–2–methylidenecyclopentanol (L3)，(+)-(1S,2R)–2-(3–hydroxy–4–methylphenyl)-1,2-[3.1.0]bicy-clohexane (L4)，()-(1S,2R) -5-hydroxy–6–methyl-spiro-dihydrobenzofuran-2(3H),2-{1-methyl-[3.1.0]bicyclohexane} (L5), (+)-6-methyl-2-(p-tolyl)hept-4-en-2,6-diol (L6)，(3R,3aS,8bS)-(-)-2,3,3a,8b–tetrahydro–7-bromo – 3 a– hydroxymethyl - 3, 6, 8b - trimethyl-1H- cyclopenta[b] benzofuran (L7 )，(3R, 3aS, 8bS) - (-) - 2,3,3a,8b–tetrahydro–3 a–hydroxymethyl-3,6,8b -trimethyl -1H – cyclopenta [b] benzofuran (L8)。25个已知结构化合物确定为：(+)-(1R,2R)-4-bromo-1,5, 9–trimethyl–12– methylidene–8–oxa-tricyclo[7.2.1.02]dodeca-2,4,6-triene (L9)，(3S,3aR,8bS)-(-)-2,3,3a, 8b– tetra -hydro–7-bromo–3–hydroxy-3,3a,6,8b-tetramethyl-1H-cyclopenta[b]benzofu- ran (L10 )，(3R, 3aR, 8bS) - (-) - 2, 3, 3a, 8b – tetrahydro – 7 - bromo – 3 – hydroxy - 3,3a,6,8b - tetramethyl - 1H - cyclopenta [b] benzofuran (L11 )，(3S,3aR,8bS) - (-) - 2, 3, 3a, 8b – tetrahydro –3–hydroxy -3, 3a, 6, 8b - tetramethyl-1H-cyclopenta[b]benzofuran (L12 )， ( 3aR, 8bS) - (-) - 3a,8b –dihydro–7 - bromo – 3, 3a, 6, 8b - tetramethyl - 1H - cyclopenta[b]benzofuran (L13 )，aplysinol (L14 ) ，aplysin (L15)，laurebiphenyl (L16)，johnstonol (L17)，gossonorol (L18)，7,10-epoxy-ar- bisabol-11-ol (L19)，10-epi-7,10-epoxyarbisabol-11-ol (L20) 3β-hydroxy- 5α, 6α-epoxy- β- ionone (L21 )，3β-hydroxy-5β,6β-epoxy-β-ionone (L22 )，胆甾醇 (L23 )，胆甾-5-烯-3β,7α二醇胆甾-5-烯-3β,7α二醇 (L24)，β-谷甾醇 (L25)，叶绿醇 (L26 )，玉米黄素 (L27 )，对羟基苯甲醛 (L28 )，3-吲哚甲醛 (L29 )，1-O-十六烷酰基-3-O-β-D-吡喃半乳糖基-丙三醇(L30 )，1-O-十八烷酰基-3-O-β-D-吡喃半乳糖基-丙三醇 (L31 )，丙三醇-1-软脂酸单酯 (L32 )，正十六碳酸 (L33 )。 采用MTT法对其中23个单体化合物在Bel-7402细胞株、BGC-823细胞株、A549细胞株、A2780细胞株、HCT-8细胞株和HELL细胞株模型上进行了细胞毒活性测试；采用MTT法对其中13个单体化合物在犬主动脉血管模型上进行了血管平滑肌细胞增殖抑制活性测试；结果表明，部分单体化合物显示出一定的生物活性。

中国沿海典型区域织纹螺毒性及毒素成分研究

织纹螺（Nassarius spp.）味道鲜美，是中国及其它一些亚洲国家沿海地区居民习惯食用的一种水产品。但是，近几十年来，中国沿海频繁发生食用织纹螺中毒事件，严重威胁着人们的身体健康和生命安全。加之人们对织纹螺体内的毒素成分、来源及其毒性变化规律还没有清晰的认识，因此难以有效预防和控制食用织纹螺引起的中毒事件。本文根据文献报道，在中国沿海食用织纹螺中毒事件多发的典型区域，包括江苏省的连云港市和盐城市、浙江省的舟山市和宁波市、福建省的宁德市、厦门市和莆田市设立了监测点，于2006年和2007年间进行了连续采样，应用小鼠生物测试法调查了织纹螺毒性的消长情况，并利用高效液相色谱-质谱联用（Liquid Chromatography-Mass Spectrometry，LC-MS）和高效液相色谱技术（High Performance Liquid Chromatography，HPLC）对织纹螺体内的毒素成分进行了分析。 实验结果表明，2006年于江苏省盐城市射阳海域采集的织纹螺样品中，阳性样品检出率为56%，毒性在2-5 MU/g组织（湿重）之间变化，在2007年于同地采集的8个样品中，除一个样品毒性为3.14 MU/g组织（湿重）以外，其余样品均表现为阴性；而2007年采集自连云港市赣榆海域的织纹螺样品，在采样期间则呈现出极高的毒性，最高达到846.52 MU/g 组织（湿重），毒性在监测期间呈“M”状波动，在5月和7月下旬出现两个毒性高峰。2006年于浙江省宁波市象山港采集的织纹螺样品中，阳性样品检出率为25%，毒性均在2.5 MU/g组织（湿重）左右；而同年采集自舟山市定海的织纹螺样品中，阳性样品检出率为100%，最高毒性达18.40 MU/g组织（湿重），毒性在监测期间也呈“M”状波动，高峰期出现在6月初和7月底。2006年3-9月采集自福建省宁德霞浦、厦门同安和莆田涵江采集的织纹螺样品中，阳性样品检出率分别为20%、43%和14%，除7月中旬采集自宁德霞浦的一个样品毒性达到16.19 MU/g组织（湿重）之外，其余样品毒性均在2-5 MU/g组织（湿重）间波动。从阳性样品的时间分布规律来看，3月份和6、7月份是阳性样品集中出现的时期。根据以上调查结果可以看出，织纹螺的毒性消长呈现出较明显的地域性和季节性特征，不同地区的织纹螺毒性存在差异，而同一区域织纹螺毒性的消长则表现出明显的季节性集中趋势。除了2007年采集自连云港赣榆的织纹螺样品毒性与其平均个体组织重量有相似的变化趋势以外，其余地区的织纹螺样品毒性和个体大小无明显相关性。 利用LC-MS和HPLC技术对织纹螺样品中的毒素成分进行了分析，确定河豚毒素（tetrodotoxin, TTX）及其同系物（trideoxyTTX，4-epi-TTX，anhydroTTX，oxoTTX）是所采集织纹螺中的主要致毒成分，样品中没有检测到麻痹性贝毒毒素（Paralytic Shellfish Poison, PSP）。自不同地区采集的织纹螺中毒素成分基本一致，但组成存在一定差异。其中，采自江苏省连云港赣榆和浙江省舟山定海的织纹螺样品中，trideoxyTTX是主要的成分，其次是TTX；而从其它采样地点采集的织纹螺中，TTX都是主要的毒素成分，其次才是trideoxyTTX及其它同系物。对采集自江苏省连云港赣榆和浙江舟山定海的织纹螺体内毒素的解剖学分布进行了分析，结果表明肌肉、消化腺和剩余部分中的毒素组成基本一致，其中trideoxyTTX是主要的毒素成分，其次为TTX，但采自浙江舟山的织纹螺剩余部分中的TTX是主要的毒素成分。在监测期间，各组织中的毒素组成没有明显变化，但毒素含量随季节变化表现出了一定的差异。 综上所述，在中国沿海典型区域开展的织纹螺毒性调查结果表明其毒性消长具有一定的地域性和季节性特征。分析结果显示织纹螺体内的毒素成分是河豚毒素及其同系物，采自不同区域的织纹螺体内毒素成分基本一致，但毒素组成稍有差异。对织纹螺中毒素的解剖学分布研究显示，各组织中的毒素含量随季节变化而表现出一定差异，但毒素组成没有明显的季节性变化。这些结果显示中国沿海的织纹螺应具有相似的毒素来源，研究结果将为相关部门有效监测、预防和控制食用织纹螺中毒事件提供有力的科学依据。

Sesquiterpenes from the red alga Laurencia tristicha

Seven new sesquiterpenes (1-7), together with seven known sesquiterpenes, aplysin (8), aplysinol (9), gossonorol (10), 7,10-epoxy-ar-bisabol-11-ol (11), 10-epi-7,10-epoxy-ar-bisabol-11-ol (12), johnstonol (13), and laurebiphenyl (14), have been isolated from the red alga Laurencia tristicha. The structures of new compounds were established as laur-11-en-2,10-diol (1), laur-11-en-10-ol (2), laur-11-en-1,10-diol (3), 4-bromo-1,10-epoxylaur-11-ene (4), cyclolauren-2-ol (5), laurentristich-4-ol (6), and ar-bisabol-9-en-7,11-diol (7) by means of spectroscopic methods including IR, HRMS, and ID and 21) NMR techniques. Compound 6 possessed a novel rearranged skeleton. All compounds were tested against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), hepatoma (Bel 7402), colon cancer (HCT-8), and HELA cell lines. Laurebiphenyl (14) showed moderate cytotoxicity against all tested cell lines, with IC50 values of 1.68, 1.22, 1.91, 1.77, and 1.61 mu g/mL, respectively. Other compounds were inactive (IC50 > 10 mu g/mL).

磁层-电离层耦合现象的分析研究

The magnetosphere-ionosphere coupling is mainly manifested by the trans- porting processes of energy into the ionosphere , the energy is carried by solar wind and firstly accumulate at the magnetosphere, and the coupling processes also significantly include the interaction between the magnetosphere and ionosphere for mass and energy. At the quiet condition, energy is delivered by the large-scale convection of the geomagnetic field; the huge energy from solar wind bulk will be injected into and consumed at the near magnetosphere and ionosphere by the geomagnetic storm and substorm activities. Aurorae and FACs (Field-aligned currents) are the important phenomena in the coupling processes. In the present work, firstly, we analyze the activity characteristics of auroral precipitating particle, secondly, we study the distribution characters of large-scale field aligned currents (LS FACs) at storm-time using the observations from different satellites at different altitudes. Finally, we investigate the evolution of the geomagnetic field configuration at the nightside sector on the onset of the expansion phase in a substorm event, the substorm event happened at 0430UT to 0630UT on 8th Nov. 2004. The main results as follows： At the first, the data of the estimated power input (EPI) of auroral particles from NOAA/POES (Polar orbiting environmental satellite) for some 30 years have been analyzed. The variation tendencies of the EPI generally coincide with aa, AE and Dst indices. The annual variation of EPI shows equinox peaks and an asymmetric-activity with a higher peak in the winter-hemisphere than in the summer-hemisphere. The diurnal UT variations are different from north and south hemisphere: for north hemisphere, the peak appears at 1200UT, and the relative deviation is 22% to the daily average of the north hemisphere. For south hemisphere, the maximal deviation is 22% at 2000UT. So the diurnal variation of EPI is more dominant than the annual variation which maximal deviation is 3% to 12% for different seasons. Studies on correlations of the hourly average of EPI, Pa, with AE and Dst indices show a correlation coefficient r=0.74 of Pa and AE, and r=-0.55 of Pa and Dst. The hourly EPIs for north and south polar regions, NPa and SPa, show a north-south asymmetry with a higher correlation of SPa and AE (or Dst). Time delays of EPI with respect to magnetic indices are examined, the maximum correlation coefficient of Pa with AE (r=0.78) occurs when the time delay =0, suggesting a synchronous activity of auroral electrojet and auroral precipitating particles, while =1-2h, the correlation coefficient of Pa with Dst is maximum (r=0.57), suggesting that the activity of auroral particle precipitating may influence the ring current on some extent. Sencondly, we use the high-resolution magnetic field vector data of the CHAMP satellite to investigate the distribution of large-scale FACs during the great magnetic storm on 7th to 8th Nov. 2004. The results show that, whether in the northern or southern hemisphere, the number and density of large-scale FACs during the main-phase are more and bigger than these during the recover-phase, and the number of large-scale FACs in morning sector obviously is more than that in afternoon sector. In terms of the magnetic indices, we find that large-scale FACs in morning sector significantly affected by the substorm activities, while in afternoon sector the large-scale FACs mainly indicate the fluctuations of the ring-current in storm time. Accordingly to the former studies, similarly, we find that in the morning sector, the scale of the large-scale FACs move to the high-latitude region, and in the afternoon sector, large-scale FACs distinctly expand to the low-latitude region. During the time periods that the NOAA/POES auroral precipitating particle power data temporally correspond to the large-scale FACs, the more the power of auroral particle is, the more and bigger the number and density of FACs are. At the same time, we use the magnetic field vector data of POLAR obtain a good form of region 1, region 2, and three pieces of cusp FACs during a single transit at 1930UT-2006UT on 07th. And the characteristics of simultaneous electric field and energy particles observations on Polar are coincide with the five FACs pieces. Finally, by means of the observation of Cluster 4 and Goes 10、 Goes 12, we analyze the evolution process of the change of the magnetic field configuration at night sector at the expansion phase of a substorm event which happened during 0430UT to 0630UT on 8th Nov. 2004, we find that the times of the beginning of the polarizations of magnetic field are observed from Goes 10 to Goes 12 then to Cluster 4. So, at the synchronous orbit ( 6.6 RE) to 10RE distance scale of the neutral sheet, the current disruption spread tailward. Simultaneously, the strengthen of the FACs deduced from these satellites’ magnetic field observations are almost consistent with the times of polarizations, as well as the high energy particles injection and the electric field dominant variation. The onset times determined by the magnetic field polarizations from these satellites are all ahead of the onset time that confirmed from the auroral electrojet indices. So, these characters of different observations can be used as the criterions to determine the onset time for the substorms of such type as we studied.

Guia para : reconhecimento dos principais insetos e ácaros praga e inimigos naturais em citros.

Manejo ecológico e uso de EPI; Devemos ter cuidado com agrotóxicos? ; Principais insetos praga dos citros; Manejo da matovegetação; Reconhecendo os inimigos naturais dos insetos praga; Literatura consultada.

Vitamin D status and requirements during pregnancy and lactation

Vitamin D deficiency during pregnancy, lactation, and early infancy has been widely reported. Current understanding of vitamin D metabolism during pregnancy and lactation is incomplete, and to date, experimental data to support vitamin D requirements for these life stages are scarce. There is a shortage of nationally representative data and appropriate reference ranges for serum 25-hydroxyvitamin D (25OHD) during pregnancy, lactation and infancy, including in umbilical cord blood. This thesis described concentrations of total 25OHD and individual metabolites including 25OHD3, 25OHD2, and 3-epi-25OHD3 at 15 weeks’ gestation in a large seasonally balanced pregnancy cohort study (n 1768), carried out in Cork, Ireland (52oN). The prevalence of low 25OHD concentrations in pregnant women was higher than published reports in other Caucasian women, and was highest among non-users of vitamin D-containing supplements during winter. A longitudinal pregnancy study was included which suggested gestational stages had an impact on the total serum 25OHD concentration. This thesis incorporated a randomized controlled trial carried out among 100 women across 3 intervention groups using 20 μg/day of vitamin D3 with or without 500 mg calcium, or placebo, over 12-weeks of lactation to investigate the vitamin D requirement for lactating mothers and the vitamin D content of human milk. A daily intake of 25 μg/day was suggested to meet the requirement of lactating women to maintain a 25OHD levels above 50 nmol/L in 97.5% of the population at 52oN all year around. However, vitamin D content in human milk did not increase in response to supplementation. Serum 25OHD concentration has been used as a predictor of a number of health outcomes. This thesis reported large differences in serum 25OHD concentrations using different methods in 86 umbilical cord samples. The need for international standardization of serum 25OHD measurements was re-emphasized in this thesis.

BOLD signal compartmentalization based on the apparent diffusion coefficient.

Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because of its sensitivity and speed. However, it is generally believed that a significant portion of these signals arises from large veins, with additional contribution from the capillaries and parenchyma. Early experiments using diffusion-weighted gradient-echo EPI have suggested that intra-voxel incoherent motion (IVIM) weighting inherent in the sequence can selectively attenuate contributions from different vessels based on the differences in the mobility of the blood within them. In the present study, we used similar approach to characterize the apparent diffusion coefficient (ADC) distribution within the activated areas of BOLD contrast. It is shown that the voxel values of the ADCs obtained from this technique can infer various vascular contributions to the BOLD signal.

Functional Variants in Notch Pathway Genes NCOR2, NCSTN, and MAML2 Predict Survival of Patients with Cutaneous Melanoma.

BACKGROUND: The Notch signaling pathway is constitutively activated in human cutaneous melanoma to promote growth and aggressive metastatic potential of primary melanoma cells. Therefore, genetic variants in Notch pathway genes may affect the prognosis of cutaneous melanoma patients. METHODS: We identified 6,256 SNPs in 48 Notch genes in 858 cutaneous melanoma patients included in a previously published cutaneous melanoma genome-wide association study dataset. Multivariate and stepwise Cox proportional hazards regression and false-positive report probability corrections were performed to evaluate associations between putative functional SNPs and cutaneous melanoma disease-specific survival. Receiver operating characteristic curve was constructed, and area under the curve was used to assess the classification performance of the model. RESULTS: Four putative functional SNPs of Notch pathway genes had independent and joint predictive roles in survival of cutaneous melanoma patients. The most significant variant was NCOR2 rs2342924 T>C (adjusted HR, 2.71; 95% confidence interval, 1.73-4.23; Ptrend = 9.62 × 10(-7)), followed by NCSTN rs1124379 G>A, NCOR2 rs10846684 G>A, and MAML2 rs7953425 G>A (Ptrend = 0.005, 0.005, and 0.013, respectively). The receiver operating characteristic analysis revealed that area under the curve was significantly increased after adding the combined unfavorable genotype score to the model containing the known clinicopathologic factors. CONCLUSIONS: Our results suggest that SNPs in Notch pathway genes may be predictors of cutaneous melanoma disease-specific survival. IMPACT: Our discovery offers a translational potential for using genetic variants in Notch pathway genes as a genotype score of biomarkers for developing an improved prognostic assessment and personalized management of cutaneous melanoma patients.