Investigação de variantes exônicas nos genes VPS35, EIF4G1 e LRRK2 como causa da doença de Parkinson em casuística brasileira

A doença de Parkinson (DP) é a segunda doença neurodegenerativa mais frequente no mundo, afetando 1-2% da população acima de 65 anos, caracterizada clinicamente por tremor em repouso, bradicinesia, instabilidade postural e rigidez muscular. Essas manifestações surgem devido à degeneração neuronal progressiva e à presença de inclusões proteicas ricas em α-sinucleína. A DP é decorrente da interação entre fatores ambientais e genéticos, e entre os fatores genéticos, variantes exônicas de transmissão dominante nos genes LRRK2 (leucine-rich repeat kinase 2), VPS35 (vacuolar protein sorting 35) e EIF4G1 (eukaryotic translation initiation factor 4-gamma 1) têm sido associadas à etiologia da doença. Entretanto, estudos sobre o efeito dessas variantes na população brasileira são raros ou inexistentes. Por essa razão, neste trabalho rastreamos mutações nos genes VPS35 (p.D620N; p.R524W), EIF4G1 (p.R1205H; p.A502V) e LRRK2 (p.G2019S) em uma amostra de 582 pacientes brasileiros com DP não aparentados e 329 indivíduos controles saudáveis. Além disso, conduzimos o primeiro estudo caso-controle para análise de variantes exônicas raras (p.Q1111H, p.T1410M, p.M1646T, p.S1761R, p.Y2189C) e comuns (p.N551K, p.R1398H, p.K1423K) no gene LRRK2 em um subgrupo de 329 pacientes brasileiros com DP, não aparentados, naturais da região sudeste. Esse subgrupo foi analisado e comparado com 222 indivíduos controles saudáveis a fim de verificar associações dessas variantes e a DP. Em relação às mutações dos genes VPS35 e EIF4G1, não foram encontradas alterações nos pacientes com DP. A mutação p.G2019S no gene LRRK2 foi encontrada em 15 probandos (2,6%), dos quais 9 são do sexo feminino (64,3%). O tremor em repouso foi observado em 47,36% dos pacientes com a mutação p.G2019S como primeiro sintoma motor. As análises das variantes raras no gene LRRK2 não revelaram qualquer associação estatisticamente significante. Entre as variantes comuns, a p.K1423K mostrou evidência de associação de risco com a DP (p<0,05) na estratificação contendo o grupo de indivíduos com história familiar da doença e para as variantes p.N551K e p.R1398H não foram observadas associações. A análise do haplótipo p.N551K-p.R1398H-p.K1423K revelou associação de proteção na amostra sudeste e na estratificação Rio de Janeiro (p<0,05). Esse haplótipo não está em desequilíbrio de ligação na amostra de 222 indivíduos controles brasileiros analisados (r2≤45). Os resultados obtidos neste estudo representam contribuições valiosas ao entendimento da relação entre as variantes genéticas estudadas e o risco de desenvolvimento da doença de Parkinson, principalmente no que se refere aos endofenótipos associados.

Stray current corrosion of copper sheathing and keel cooling pipe of a 36' trawler

The results of investigations into the cause of an accelerated corrosion of copper sheathing and keel cooling pipe of a 36' wooden trawler are reported. The corrosion is attributed to the stray electric currents originating from the electrical wiring system. The sources of stray currents and the remedial measures have been suggested.

云南滇池濒危特有种滇池金线鲃人工繁殖初报

滇池金线鲃(Sinocyclocheilus grahami)是滇池湖泊生态系统的指示物种和特有种.因水质污染和外来物种入侵等因素的影响,该鱼类自1986年起就从湖体中消失,仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃.至2007年3月初,有两次繁殖试验取得了成功.先后试验了5尾雌鱼和6尾雄鱼,获得鱼卵约1 600粒,并实施干法受精.约有1 320粒受精,平均受精率为73%.孵化出鱼苗约480尾,平均孵化率为36%.经10天饲养,约有95%以上的鱼苗存活,体长达8-12 mm.滇池金线鲃人工繁殖成功的意义有三点:能有效保护该物种免于灭绝;繁殖的鱼苗放归湖泊合适水域,将有助于恢复滇池的土著生物多样性;有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变.

Detection of the hepatotoxic microcystins in 36 kinds of cyanobacteria Spirulina food products in China

Gel filtration chromatography, ultra-filtration, and solid-phase extraction silica gel clean-up were evaluated for their ability to remove microcystins selectively from extracts of cyanobacteria Spirulina samples after using the reversed-phase octadecylsilyl ODS cartridge for subsequent analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The reversed-phase ODS cartridge/silica gel combination were effective and the optimal wash and elution conditions were: H2O (wash), 20% methanol in water (wash), and 90% methanol in water (elution) for the reversed-phase ODS cartridge, followed by 80% methanol in water elution in the silica gel cartridge. The presence of microcystins in 36 kinds of cyanobacteria Spirulina health food samples obtained from various retail outlets in China were detected by LC-MS/MS, and 34 samples (94%) contained microcystins ranging from 2 to 163 ng g(-1) (mean=1427 ng g(-1)), which were significantly lower than microcystins present in blue green alga products previously reported. MC-RR-which contains two molecules of arginine (R)-(in 94.4% samples) was the predominant microcystin, followed by MC-LR-where L is leucine-(30.6%) and MC-YR-where Y is tyrose-(27.8%). The possible potential health risks from chronic exposure to microcystins from contaminated cyanobacteria Spirulina health food should not be ignored, even if the toxin concentrations were low. The method presented herein is proposed to detect microcystins present in commercial cyanobacteria Spirulina samples.

镍-金属氢化物电池新型负极材料研究

贮氢合金是镍一金属氢化物电池的核心材料，其综合性能的改善是提高镍一金属氢化物电池性能的关键。本研究以探索镍一金属氢化物电池新型负极材料为目的，以非ABS型贮氢合金为研究对象，采用X射线衍射、Rietveld分析、恒电流充／放电、P-C-T曲线及线性微极化等方法，从基础和潜在应用等方面详细研究了非ABS型合金的结构与电化学性能。对La-Ni体系中非ABS型二元合金的结构和电化学性能的研究表明，LaNi_(228)具有最优异的高倍率充电性能；La_2Ni_7合金电极的高倍率放电性能最佳；La_7Ni_3在低温条件下表现出较好的放电性能。然而，所有得到的La-Ni合金电极容量远低于其理论容量。因此，必须通过进一步研究，如元素取代、热处理、表面处理等来提高其电化学容量。对RENi_3（RE＝La，Ce，Pr，Nd，Sm，Gd，Th，Dy，Ho，Er，Y）研究表明：YNi_3合金因其具有最大的晶胞体积，最小的密度，而表现出最好的高倍率充／放电性能及低温放电性能，但其高温放电性能需要进一步提高，以满足实际应用的要求。用Al、Mn、Ti、Fe、Sn、Si、Cr、M。、Cu和Co十种元素取代Ni进行了大量的配方筛选工作。得到了大量的实验数据，并发现LaNi_(3.7)Al_(0.3)合金电极电化学放电容量最高，达290.8mAh／g；LaNi_(3.7)Mo_(0.3)合金电极的高倍率放电性能最好，在以4200mA/g的电流密度下进行放电时，其放电容量仍达到145.8mA/g；而I镍一金属氢化物电池新型负极材料研究镍一金属氢化物电池新型负极材料的研究Al的取代会使合金电极性能对温度不敏感。以我们的实验为基础，进一步进行合金配方的微调，具有可能开发出具有实用价值的贮氢合金的潜力。在Ar保护下用真空电弧炉熔炼合成了四种Lal一xMg：（NICoAI）3．6体系贮氢合金，制成姐卜Ni电池负极，通过恒电流充／放电方法研究了其电化学性能。结果表明：Lal一xMg：（NiCoAI）3．6体系金属氢化物电极较容易活化，室温下具有优异的高倍率放电性能，在以4200mA／g电流放电时，La卜汉gx（NICoAI）36合金电极的放电容量是ABS型合金电极的3倍，达152hah／g，显示出良好的动力学特性。R，入1兮Ni（R：raree田劝，Ca，Y）型合金因能吸引／释放1．8一1．87％质量的HZ而被认为是种很有希望的贮氢合金。但其吸／放氢平台过高，循环寿命短。如何提高Rh厦g剑19循环稳定性是这类合金能否成功商业化的关键。研究发现，Co能够显著提高ABS型合金电极的循环寿命，但其价格太贵。人们发现Al在提高电极寿命方面与C。有类似的作用，但Al元素的添加因其在碱性电解质的作用下在电极表面易生成致密的氧化膜而不利于氢的扩散，进而对高倍率放电性能不利。入物在提高电极表面活性，改善其高倍率放电性方面作用明显。本工作在前面的基础上用Al和MO联合取代Ni，以期待同时改善La一Mg一Ni一Co合金的循环稳定性和高倍率放电性能。详细研究了La07Mg03Ni切一（A105Mo05）x（x：o，0．2，0．4，0．6，0．8）系列贮氢合金的晶体结构和电化学性能。X射线衍射及Rietveld分析发现：所有La07Mg03Ni4D一x（A105Mo05）x合金均为包含PuNi3结构的六方LaZMgNig相、CaCus结构的LaNis主相及L匆Ni7，LaN儿和LaNi杂相的多相结构。合金中La（La，Mg）剑19相及LaNis相的晶格参数及晶胞体积均随合金中Al和Mo含量的增加而增大。用电化学方法测得的RC一T曲线显示：Al和'fo部分取代Ni降低了氢的平台压力。随合金中Al和Mo含量的增加，电极的电化学容量从329．7（x＝0）、徽橇毓孺鑫盆一11瀚加至365．物A吨（＝0．6）后又降低到351．3毗吨（x＝0．8）。当以1200m刀g的电流密度进行放电时，其I｛RD从62．0％沁0）增加到82．1％沁0．8）。线性微极化结果显示：Al和Mo的添加增大了合金表面的交换电流密度，因而也改善了合金电极的高倍率放电性能。另外，Al和M。取代合金中的Ni增大了氢在电极合金中的扩散系数（D），改善了La07Mgo3Ni4。一x（Alo5M。。5）x（X＝o，0．2，0．4，0．6，0．8）合金电极的低温放电性能（LTD）。

Temperature-stimulated abnormal annealing of neutron-induced damage in high-resistivity silicon detectors

Neutron-irradiated high-resistivity silicon detectors have been subjected to elevated temperature annealing (ETA). It has been found that both detector full depletion voltage and leakage current exhibit abnormal annealing (or ''reverse annealing'') behaviour for highly irradiated detectors: increase with ETA. Laser induced current measurements indicate a net increase of acceptor type space charges associated with the full depletion voltage increase after ETA. Current deep level transient spectroscopy (I-DLTS) and thermally stimulated current (TSC) data show that the dominant effect is the increase of a level at 0.39 eV below the conduction band (E(c) - 0.39 eV) or a level above the valence band (E(v) + 0.39 eV). Candidates tentatively identified for this level are the singly charged double vacancy (V-V-) level at E(c) - 0.39 eV, the carbon interstitial-oxygen interstitial (C-i-O-i) level at E(v) + 0.36 eV, and/or the tri-vacancy-oxygen center (V3O) at E(v) + 0.40 eV.

MOCVD生长Al_(0.48)Gao_(0.52)N/Al_(0.54)Ga_(0.36)N多量子阱的结构和光学特性

采用金属有机物化学气相淀积(MOCVD)技术,在蓝宝石衬底上生长了Al_(0.48)Gao_(0.52)N/Al_(0.54)Ga_(0.36)N多量子阱(MQWs)结构.通过双晶X射线衍射(DCXRD)、原子力显微镜(AFM)和阴极荧光(CL)等测试技术,分别对样品的结构和光学特性进行了表征.在DCXRD图谱中,可以观察到明显的MQWs衍射卫星峰,通过拟和,MQWs结构中阱和垒的厚度分别为2.1和9.4 nm,Al组分分别为0.48和0.54.在AFM表面形貌图上,可以观察到清晰的台阶流,表明MQWs获得了二维生长;与此同时,MQWs结构存在一些裂缝,主要原因为AlGaNMQWs结构和下层GaN层间存在很大的应力.CL测试表明,AlGaN MQWs结构的发光波长为295 nm,处于深紫外波段,同时观察到处于蓝光、绿光波段的缺陷发光.

One-Dimensional InP-Based Photonic Crystal Quantum Cascade Laser Emitting at 5.36μm

An InP-based one-dimensional photonic crystal quantum cascade laser is realized. With photo lithography instead of electron beam lithography and using inductively coupled plasma etching, four-period air-semiconductor couples are defined as Bragg reflectors at one end of the resonator. The spectral measurement at 80K shows the quasi-continuous-wave operation with the wavelength of 5.36μm for a 22μm-wide and 2mm-long epilayer-up bonded device.