福建闽南地区汉族与畲族的指长比

本文旨在研究福建闽南地区汉族和畲族指长比(R)的特点。随机选择福建闽南地区汉族506例（男性173例,女性333例）,畲族450例（男性231例,女性219例）,采用体质测量法,测量并计算左右侧6项指长比（R_2/3、R_2/4、R_2/5、R_3/4、R_3/5、R_4/5）。福建闽南地区汉族和畲族左、右侧指长比均呈R_2/3<R_2/4<R_3/4<R_2/5<R_4/5<R_3/5的趋势;汉族女性指长比左侧R_2/3、R_2/4、R_2/5、R_3/4、R_3/5和右侧R_2/3、R_2/4、R_2/5高于汉族男性（P<0.05）;畲族女性指长比左侧的R_2/3、R_2/4、R_2/5和右侧R_2/3、R_2/4高于畲族男性（P<0.05）;畲族男性指长比左、右侧R_2/3、R_2/4、R_2/5、R_3/5、R_4/5高于汉族男性（P<0.05）;畲族女性指长比左侧R_2/3、R_2/4和右侧R_2/3、R_2/4、R_2/5、R_4/5高于汉族女性（P<0.05）。同民族不同性别两侧R_2/4百分比分布差异有统计学意义,不同民族同性别右侧R_2/4百分比分布差异有统计学意义。福建闽南地区汉族和畲族指长比存在性别、侧别的不同,与其他地区、族群也存在差异。     

黑沙蒿光合能量分配组分在生长季的相对变化与调控机制

为了探明典型荒漠灌木优势物种黑沙蒿(俗名油蒿, Artemisia ordosica)光合过程能量中分配对环境波动的相对变化及其长期调节机制, 该研究于2018年4-10月在宁夏盐池毛乌素沙地, 同时使用MONITORING-PAM多通道荧光监测仪和LI-6400XT便携式光合测量仪对黑沙蒿叶片的最小荧光产量(F_o)、最大荧光产量(F_m)、稳态荧光产量(F_s)、光下最大荧光产量(F_m′)、净光合速率(P_n)、暗呼吸速率(R_d)、蒸腾速率(E)和叶片气孔导度(g_s)进行现场测定, 在实验室内计算比叶面积(SLA)、单位面积氮含量(N_area)、叶绿素含量(C_Chl)和叶绿素a/b (Chl a/b), 分析黑沙蒿光合过程能量分配中固碳耗能占比(Φ_A)、光呼吸耗能占比(Φ_PR)、调节性热耗散耗能占比(Φ_NPQ)和非调节性热耗散耗能占比(Φ_NO)与环境参数和叶性状参数之间的关系以及能量分配各组分之间的相对变化。结果表明, 光化学反应组分(Φ_A、Φ_PR)和热耗散组分(Φ_NPQ、Φ_NO)之间呈负相关竞争关系, 两组分内部呈正相关协同关系, E和Φ_A、Φ_PR正相关, 和Φ_NPQ、Φ_NO负相关。在低土壤含水量(SWC)和高饱和水汽压差(VPD)环境条件下, 黑沙蒿Φ_A、Φ_PR和SLA显著降低, Φ_NPQ和Φ_NO显著增加。研究认为, 在长期干旱或高蒸散条件下, 黑沙蒿通过降低SLA等途径避免水分的过度流失, 同时将部分过剩光能由光呼吸代谢途径转移到热耗散组分进行耗散。波动环境下黑沙蒿形态性状的变异和光合过程能量分配的长期调节机制, 反映了其利用形态与生理的协同可塑性对逆境的适应。     

双生子多巴胺D3受体基因多态性对儿童体成分的影响

均衡的体成分构成对维持机体的健康状态具有重要作用,体成分受遗传与环境因素的共同影响。多巴胺参与摄食、运动及认知等活动的调节,多巴胺D3受体（DRD3）对多巴胺神经通路起关键调节作用,进而对摄食功能发挥作用,从而可能对体成分产生影响。为了解遗传与环境因素对双生子儿童体成分的影响,并探讨DRD3基因单核苷酸多态性（SNP）与体成分的相关性,对160对4-12岁双生子肱三头肌皮褶厚度（d₁）、肩胛下皮褶厚度（d₂）、髂前上棘位皮褶厚度（d₃）和体质量（m）进行了测量,计算d₄(d₁+d₂)、d₅(d₂/d₁),体脂率（P_f）、瘦体质量（m_l）;从口腔拭子中提取全基因组DNA;通过Amp FISTR Sino filerPlus试剂盒分析确定卵型;采用SNaPshot技术对DRD3基因4个SNP位点进行检测;使用Mx软件估算各指标遗传度;运用广义估计方程模型分析各指标与DRD3基因SNP的相关性。校正年龄效应后,除个别指标（d₃, m_l）外,男女生指标遗传度（h）学龄前期总体偏低,且某些指标（d₂, d₄, P_f, m_l）的遗传度存在一定的性别差异。d₂分别与rs324029、rs226082存在相关（P<0.05）; d₃分别与rs2134655、rs226082存在相关（P<0.05）;d₅分别与rs2134655、rs167771存在相关（P<0.05）;P_f分别与rs226082、rs167771存在相关（P<0.05）;m_l分别与rs2134655、rs226082、rs167771存在相关（P<0.05）。本研究结果表明,遗传和环境因素对儿童体成分发育均有影响,但遗传效应可能存在一定的发育阶段和性别差异;DRD3基因SNPs与儿童的体成分可能存在一定的相关性。     

蒸散发广义互补原理中关键参数αe的时空变化特征及计算方法分析

蒸散发广义互补原理是实测数据稀少条件下估算蒸散发的重要方法, 其中准确估算参数α_e是应用该方法的关键。该研究利用中国不同气候和生态类型的8个通量站数据, 首先基于实测数据校准得到α_e年值及月值, 探究α_e的时空变异性并对比使用不同时间尺度的α_e对广义互补原理模型计算精度的影响。考虑到实际情况下蒸散发实测数据缺乏而无法校准得到α_e, 进一步探究两个基于干旱系数(AI)的α_e年值统计模型(下称Liu法和Brutsaert法)在站点尺度的适用性, 明确α_e是否可以利用AI确定, 最后探讨各计算方法的误差来源。主要结论如下: 1)季节变化影响α_e, 不同通量站α_e月值变化规律有所差异; 在空间变化上, 湿润站点α_e年值总体大于干旱站点。Liu法和Brutsaert法计算的α_e接近年校准值。2)在应用广义互补原理模型时, 使用校准α_e年值能取得较好的模拟精度, 使用各月份α_e时精度进一步提升。两种基于AI的免校准方法取得较好的模拟效果, 当缺少实测数据而无法校准α_e时, 基于AI计算α_e具有较大的潜力。3)使用校准α_e年值时广义互补原理模型能模拟出蒸散发的年内变化趋势, 但在部分月份估算值出现偏差。Liu法和Brutsaert法计算的蒸散发在干旱站点的夏季月份呈现低估现象, 原因可能在于高估了降雨集中的夏季月份的AI。结果也进一步验证了广义互补原理在估算广泛不同的自然环境下的蒸散发的潜力。     

光系统II实际光化学量子效率对光的响应模型的比较

为了比较光系统II实际光化学量子效率(Φ_PSII)对光的响应机理模型(简称机理模型)、负指数模型和指数模型的优缺点, 用LI-6400-40B光合作用测定仪控制CO₂浓度和温度, 测量了剑叶金鸡菊(Coreopsis lanceolata)、黄荆(Vitex negundo)和大狼杷草(Bidens frondosa)的电子传递速率(ETR)对光的响应曲线(ETR-I)和Φ_PSII对光的响应曲线(Φ_PSII-I), 然后用这3个模型分别拟合了这些数据。拟合结果表明: 3个模型都可以较好地拟合这3种植物的ETR-I的响应数据和Φ_PSII-I的响应数据, 但由指数模型拟合ETR-I和Φ_PSII-I的响应数据得到相应的饱和光强(PAR_sat)和光系统II最大光能利用效率(F_v/F_m)之间存在显著差异, 且估算的饱和光强远低于实测值。由机理模型可知, Φ_PSII不仅与光强的函数有关, 还与植物的内禀特性有关, 即与天线色素分子的本征光能吸收截面、激子的传递效率、能级的简并度、光化学反应常数、热耗散常数和处于最低激发态的平均寿命等参数有关。此外, 由机理模型还可知, Φ_PSII随光强的增加而下降的原因是捕光色素分子的有效光能吸收截面随光强增加而降低。     

黑河中游春玉米叶片水δD和δ18O的富集过程和影响因素

植物水的稳定同位素分馏过程是水在土壤-植物-大气连续体中循环的重要环节。以往研究由于叶片水¹⁸O同位素比值(δ¹⁸O _l,b)和氘(D)同位素比值(δD_l,b)(合称δ_l,b)实测数量少只能作为模型验证数据, 导致δ_l,b富集机制研究多集中于模型研究, 缺乏基于野外试验条件的δ_l,b富集的控制机制研究。叶片水δD_l,b和δ¹⁸O _l,b的富集程度(ΔD_l,b和Δ¹⁸O _l,b, 合称Δ_l,b)通常表示为δ_l,b与茎秆水D同位素比值(δD_x)和¹⁸O同位素比值(δ¹⁸O_x) (合称δ_x)之差, 即Δ_l,b = δ_l,b - δ_x。该研究以黑河中游沙漠绿洲春玉米(Zea mays)生态系统为研究对象, 重点采集和分析了季节和日尺度δ_l,b和δ_x数据, 配套开展了大气水汽δ¹⁸O和δD (合称δ_v)等辅助变量的原位连续观测, 探讨了季节和日尺度上的δ_l,b富集特征及其影响因素。结果表明: 叶片水δ_l,b和Δ_l,b的季节变化趋势不明显, 而受蒸腾作用影响表现出白天富集夜间贫化的单峰日变化特征。对于D来说, 无论季节尺度上还是日尺度上, 大气水汽δ_v和相对湿度是δD_l,b和ΔD_l,b的主要环境控制因素; 而对于¹⁸O来说, 无论季节尺度上还是日尺度上, 相对湿度是δ¹⁸O _l,b和Δ¹⁸O _l,b的主要环境控制因素。由于D和¹⁸O在热力学平衡分馏上有约8倍差异, 直接分析叶片水ΔD_l,b和Δ¹⁸O_l,b与影响因素的差异性, 有助于理解叶片水δD和δ¹⁸O富集过程以及对模型发展有一定的指导意义。     

北京2种阔叶树不同高度枝干的呼吸速率及其对温度的敏感性

该研究采用红外气体分析法(IRGA)于2013年3-12月原位测定了北京市东升八家郊野公园中2个主要阔叶树种(槐(Sophora japonica)、旱柳(Salix matsudana)) 3个高度上的枝干呼吸(R_w)日进程, 旨在量化R_w的种间差异, 探索种内R_w及其温度敏感系数(Q₁₀)的时间动态和垂直分布格局。研究结果显示: (1) R_w在不同树种之间差异明显, 相同月份(4月份除外)槐R_w是旱柳的1.12 (7月)-1.79倍(5月)。两树种枝干表面CO₂通量速率均表现出明显的单峰型季节变化, 峰值分别出现在7月((5.13 ± 0.24) μmol·m^-2·s^-1)和8月((3.85 ± 0.17) μmol·m^-2·s^-1)。同一树种在生长月份内的平均呼吸水平显著高于非生长季, 但其Q₁₀值季节变化趋势与之相反。(2) R_W随测量高度的增加而升高, 并在3个高度上表现出不同的日变化规律: 其中, 树干基部及胸高位置为单峰格局, 而一级分枝处的呼吸速率在一天内存在两个峰值, 中间出现短暂的“午休”现象。温度是造成一天内呼吸变化的主要原因。此外, 顶部R_w及其对温度的敏感程度明显高于基部。温度本身和Q₁₀值差异可在一定程度上解释R_W的垂直梯度变化。(3)在生长月份, 单位体积木质组织的日累积呼吸速率(mmol·m^-3·d^-1)与受测部位直径倒数(D^-1)呈极显著正相关关系。单位面积(μmol·m^-2·s^-1)可准确表达两树种在生长期间的R_W水平, 能合理有效地比较不同个体的呼吸差异及同一个体的时空变异。这些结果表明, 采用局部通量法上推至树木整体呼吸时, 应全面考虑R_w的时、空变异规律, 并选择恰当的表达单位, 以减小估测误差。     

长白山阔叶红松林生态系统光能利用率的动态变化及其主控因子

生态系统光能利用率(LUE)反映了植被通过光合作用利用光能吸收和固定大气中CO₂的能力, 是表征生态系统生产力的重要指标。选取长白山温带阔叶红松(Pinus koraiensis)林生态系统为研究对象, 利用涡度相关通量观测数据, 采用直角双曲线方程获取了生态系统光合作用的表观量子效率(ε); 基于总生态系统初级生产力(GEP)与下垫面入射光合有效辐射(Q)的比值得到生态光能利用率(LUE_eco)。研究表明: 在季节尺度上, ε与LUE_eco均表现出显著的单峰变化特征, 并主要受到土壤温度和归一化植被指数(NDVI)的调控, 同时, ε和LUE_eco都受到GEP的显著影响, 而与Q的相关性较弱或无显著相关关系, 但散射辐射的增加在一定程度上有助于提高生态系统的LUE。ε与LUE_eco存在显著的线性正相关关系, 但ε明显高于LUE_eco。2003-2005年, ε与LUE_eco每年最大值的平均值分别为(0.087 ± 0.003)和(0.040 ± 0.002) μmol CO₂·μmol photon^-1, 年际间变异度分别为4.17%和4.25%, 而不同年份之间最大差异均达到8%或8%以上, 从而对模型模拟结果产生明显影响。因此, 在基于光能利用率模型的模拟研究中, 最大LUE的年际变异需要在参数反演和优化中给予重要考虑。     

商代前期中原地区多品种农作物种植制度的初探：以河南新郑望京楼遗址为例

农业经济的发展是华夏文明形成的最重要的前提条件之一,郑洛地区作为夏商王朝建都和统治的核心区域,其农业经济发展状况一直是学术界研究的重点问题。相关研究表明,多品种农作物种植制度在龙山时期中原地区的出现,在华夏文明的形成过程中可能起到了至关重要的作用。为了探索这一种植制度在商代前期中原地区的具体实践情况,本文选取河南新郑望京楼遗址夏商时期（二里头文化和二里岗文化时期）29例先民肢骨和23例先民肋骨进行C、N稳定同位素分析。结果表明,先民骨胶原的δ¹³C值变化范围为-18.1‰~7.0‰,平均值为-9.5‰±2.1‰（n=52）,δ¹⁵N值变化范围为7.3‰~10.5‰,平均值为8.9‰±0.7‰（n=52）,先民仍以C₄类食物（粟黍）为主,但是也包含少量C₃类（水稻、小麦或大豆）食物,证明中原地区自龙山时代出现的多品种农作物种植制度,在商代得以延续,但是粟作农业的主导地位,始终未发生明显变化,这可能与中原地区长期以来的旱作农业经济模式习惯有关。     

山西庞泉沟银露梅群落物种多样性的海拔格局

采用样地调查的方法, 对山西庞泉沟银露梅(Potentilla glabra)群落的结构特征、物种多样性随海拔梯度的变化以及沿海拔梯度群落的相似性进行了研究, 并通过R语言对群落α多样性指数间的相关性进行了分析。结果表明: (1) 银露梅群落各层的α多样性指数除生态优势度指数(D)沿海拔梯度的变化不明显外, 其它各指数的变化基本一致。银露梅群落在海拔 1 700-1 900 m与2 100-2 300 m区间内, 灌木层和草本层的α多样性指数均较高, 在海拔1 900-2 000 m区间则较低。另外, 银露梅群落各α多样性指数间除J₂外均呈显著正相关。(2) 随着海拔间隔的增加, 灌木层和草本层的4个β多样性指数的变化均呈上升趋势, 并且草本层随海拔间隔的增加β多样性指数整体比灌木层高。(3) 银露梅群落Jaccard相似性指数随着海拔间隔的增大逐渐减小, 而当海拔达到2 300 m以上时, 群落间的相似性升高, 群落相对稳定。     

Structures and magnetism of rubidium and cesium salts of dimeric oxovanadium(IV) tartrate(4−) complexes

Complexes of type A₄[VO(tart)]₂·nH₂O, where A = Rb or Cs and tart =d,l-tartrate(4−) (n = 2) or d,d-tartrate(4−) (n = 2 for Rb and n = 3 for Cs), were prepared from an aqueous mixture of V₂O₅, AOH and H₄tart. These complexes were studied by single-crystal X-ray diffraction methods: Rb₄[VO(d,l-tart)]₂·2H₂O, space group P1 with a = 8.156(1),b = 8.246(1),c = 8.719(1)Å, = 66.09(1)°, β = 65.07(1)°, γ = 82.40(1)°,Z = 2, 1917 observed reflections, and final R_w = 0.035; Cs₄[VO(d,l-tart)]₂·2H₂O, space group P₂₁/c with a = 9.350(1),b = 13.728(2),c = 8.479(1)Å, β = 106.77(1)°,Z = 4, 2235 observed reflections, and final R_w = 0.054; Rb₄[VO(d,d-tart)]₂·2H₂O, space group P₄₁₂₂ with a = 8.072(1),c = 32.006(3)Å,Z = 8, 1014 observed reflections and final R_w = 0.038; Cs₄[VO(d,d-tart)]₂·3H₂O, space group P₁₂₂ with a = 8.184(1),c = 33.680(5)Å,Z = 8, 1310 observed reflections, and final R_w = 0.063. Bulk magnetic susceptibility data (1.5–300 K) for these compounds and A₄[VOl,l-tart)]₂·nH₂O (A = Rb, Cs) were obtained on polycrystalline samples. These data were analyzed in terms of a Van Vleck exchange coupled S = 1/2 model which was modified to include an interdimer exchange parameters Θ. Analysis of the low-temperature (1.5–20 K) susceptibility data gave 2J = +1.30 cm⁻¹ and Θ = −1.86 K for Rb₄[VO(d,l-tart)]₂·2H₂O, 2J = +1.16 cm⁻¹ and Θ = −1.69 K for Cs₄[VO(d,l-tart)]₂·2H₂O, 2J = +1.90 cm⁻¹ and Θ = −0.82 K for Rb₄[VO(d,d-tart)]₂·2H₂O, 2J = +2.04 cm⁻¹ and Θ = −0.80 K for Rb₄[VO(l,l-tart)]₂·2H₂O, 2J = +1.52 cm⁻¹ and Θ = −0.25 K for Cs₄[VO(d,d-tart)]₂·3H₂O, and 2J = +1.64 cm⁻¹ and Θ = −0.31 K for Cs₄[VO(l,l-tart)]₂·3H₂O. These results suggest the magnitudes of intradimer (ferromagnetic and interdimer (antiferromagnetic) exchange interactions are similar in these complexes, as observed for the analogous Na salts.     

Crystal and molecular structure of μ-oxo-bis((5,10,15,20)tetrakispentafluorophenyl)porphinatoiron(III)

In this paper, we report the crystal and molecular structure of μ-oxo-bis(5,10,15,20)tetrakispentafluorophenyl)porphinatoiron(III) [(TPP(F₅)Fe)₂O]. The crystals belong to the tetragonal system, space group I4₁/a, with a =b = 26.362(7),c = 30.886(8)Å,V = 21465ų,Z = 8 and D_calc = 1.496. Discrepancy indices are R₁ = 0.084 and R₂ = 0.104 for 3320 reflections having I3σ(I). The FeN_p average distance, 2.088(11)Å, is at the long end of the range of high-spin ferric porphyrin while the FeO distances (1.775(1)Å) are similar to those of the non-halogenated analog (TPPFe)₂O. The FeOFe angle of 178.4(5)° shows an essentially linear oxo bridge. The 0.673(2)Ådisplacement of the iron atom from the porphyrin mean plane is unusually large. The facing porphyrin rings are twisted 47° with respect of each other giving the molecule nearly exact D_4d symmetry.     

Dihydroxamic acid complexes of iron (III): ligand pKa and coordinated water hydrolysis constants

A series of dihydroxamic acid ligands of the formula [RN(OH)C(O)]₂(CH₂)_n, (n = 2, 4, 6, 7, 8; R = CH₃, H) has been studied in 2.0 M aqueous sodium perchlorate at 25.0 °C. These ligands may be considered as synthetic analogs to the siderophore rhodotorulic acid. Acid dissociation constants (pK_a) have been determined for the ligands and for N-methylacetohydroxamic acid (NMHA). The pK_a1 and pK_a2 values are: n = 2, R = CH₃ (8.72, 9.37); N = 4, R = CH₃ (8.79, 9.37); N = 6, R = CH₃; N = 7, R = CH₃ (8.95, 9.47); N = 8, R = CH₃ (8.93, 9.45); N = 8, R = H (9.05, 9.58). Equilibrium constants for the hydrolysis of coordinated water (log K) have been estimated for the 1:1 feeric complexes of the ligands n = 2, 4, 8; R = CH₃. The N = 8 ligand forms a monomeric complex with Fe(III) while the n = 2 and 4 ligands form dimeric complexes. For hydrolysis of the n = 8 monomeric complex, log K₁ = −6.36 and log K₂ = −9.84. Analysis of the spectrophotometric data for the dimeric complexes indicates deprotonation of all four coordinated waters. The successive hydrolysis constants, log K_1–4, for the dimeric complexes are as follows: n = 2 (−6.37, −5.77, −10.73, −11.8); n = 4 (−5.54, −5.07, −11.57, −10.17). The log K₂ values for the dimers are unexpectedly high, higher in fact than log K₁, inconsistent with the formation of simple ternary hydroxo complexes. A scheme is proposed for the hydrolysis of the ferric dihydroxamate dimers, which includes the possible formation of μ-hydroxo and μ-oxo bridges.     

The synthesis and structural characterization of carborane oligomers connected by carbon-carbon and carbon-boron bonds between icosahedra

The reaction of dilithiated o-carborane (closo-1,2-Li₂-1,2-C₂B₁₀H₁₀) with CuCl₂ gives 1,1′-bis(o-carborane) (1), 1,3′-bis(o-carborane) (2) and 1,4′-bis(o-carborane) (3). Compound 2 (C₄B₂₀H₂₂) crystallizes in the monoclinic space group P2₁/n with A = 6.9275(6), B = 9.7655(8), C = 12.356(1) Å, β = 90.028(2)° and Z = 2. The structure was solved by direct methods and refined to R = 0.048 and R_w = 0.074. Compound 3 (C₄B₂₀H₂₂) crystallizes in the orthorhombic space group P2₁2₁2₁ with A = 6.8854(5), B = 12.523(1), C = 19.847(1) Å and Z = 4. The structure was solved by direct methods and refined to R = 0.078 and R_w = 0.091. The coupling reaction of dilithiated m-carborane (closo-1,7-Li₂-1,7-C₂B₁₀H₁₀) with CuCl₂ results in the formation of 1,1′-bis(m-carborane) (4) and tetra(m-carborane) (5).     

The effects of in vivo and in vitro non-enzymatic glycosylation and glycoxidation on physico-chemical properties of haemoglobin in control and diabetic patients

The erythrocyte deformability, which is related to erythrocyte internal viscosity, was suggested to depend upon the physico-chemical properties of haemoglobin. In the present study we employed ESR spectroscopy in order to explore further the extent to which the in vivo or in vitro glycation and/or glycoxidation might affect haemoglobin structure and conformation. We revealed that under both in vivo and in vitro conditions the attachment of glucose induced a mobilization of thiol groups in the selected domains of haemoglobin molecules (the increased h₊₁/h₀ parameter of maleimide spin label, MSL; 0.377 ± 0.021 in diabetics vs 0.338 ± 0.017 in controls, n = 12, P < 0.0001). The relative rotational correlation time (τ_c) of two spin labels, TEMPONE and TEMPAMINE, respectively, in erythrocyte insides (5.22 ± 0.42 in diabetics, n = 21 vs 4.79 ± 0.38, n = 16 in controls, P < 0.005) and in the solutions of in vitro glycated haemoglobin, were increased. Neither oxidation nor crosslinking of thiol groups was evidenced in glycated and/or oxidized haemoglobin. In addition, erythrocyte deformability was found to be reduced in type 2 diabetic patients (6.71 ± 1.08, n = 28 vs 7.31 ± 0.96, n = 21, P < 0.015). In conclusion, these observations suggest that: the attachment of glucose to haemoglobin might have decreased the mobility of the Lys-adjacent Cys residues, thus leading to the increased h₊₁/h₀ parameter of MSL. Such structural changes in haemoglobin owing to non-enzymatic glycosylation may contribute to the increased viscosity of haemoglobin solutions (r = 0.497, P < 0.0035) and the enhanced internal viscosity of diabetic erythrocytes (r = 0.503, P < 0.003). We argue that such changes in haemoglobin, and consequently in red blood cells, might contribute to the handicapped oxygen release under tissue hypoxia in the diabetic state.     

The synthesis, fluctionality and structural characterization of ReMo3H4(CO)12

The reaction of ReH₉²⁻ with Mo(diglyme)(CO)₃ leads to the formation of the mixed metal cluster trianion, ReMo₃H₄(CO)₁₂³⁻. This species has been characterized analytically, spectroscopically and through X-ray diffraction analysis. A pseudo-tetrahedral arrangement of M(CO)₃ fragments is adopted, such that each set of three carbonyl ligands eclipses the adjacent three tetrahedral edges, an apparent result of the location of the hydride ligands on the tetrahedral faces. Variable temperature NMR studies revealed a fluctional process for some of the carbonyl ligands, but not for the hydrides. Crystal data for [Me₄N]₃[ReMo₃H₄(CO)₁₂]·THF; space group P2₁/n, a = 12.157(2), B = 21.480(4), C = 15.964(3) Å, β = 98.26(1)°, Z = 4, R = 0.067 and R_w = 0.076.     

Ruthenium complexes containing tertiary phosphines and imidazole or 2,2′-bipyridine ligands

Complexes RuCl₃(PPh₃)L₂ (L = MeIm (1a, Im (1b)) and [RuCl₂(PPh₃)₂(bipy)]Cl·4H₂O (2) have been synthesized via the ruthenium(III) precursor RuCl₃(PPh₃)₂ (DMA), and characterized, including an X-ray structural analysis for 1a (MeIm = N-methylimidazole, Im = imidazole, bipy = 2,2′-bipyridyl, and DMA = N, N′-dimethylacetamide). Crystals of 1a are monoclinic, space group P2₁/n, A = 10.5491(5), B = 20.4934(9), C = 12.8285(4) Å, β = 90.166(4)°, Z = 4. The structure, which reveals a mer configuration for the chlorides, and cis-methylimidazoles, was solved by conventional heavy atom methods and was refined by full-matrix least-square procedures to R = 0.041 and R_w = 0.042 for 3328 reflections with I 3σ(I). From the RuCl₂(PPh₃)₃ precursor, the ruthenium(II) complexes RuCl₂(PPh₃)₂L₂ and [RuCl(PPh₃)L₄]Cl have been made (L = Im or MeIm), while [RuCl(dppb)Im₃]Cl has been made from [RuCl₂(dppb)]₂(μ-dppb) (dppb = Ph₂P(CH₂)₄PPh₂).     

Molecular structures and some properties of tris(2-aminoethyl) amine cobalt(III) complexes with thiocarboxylato-O,S such as 3-mercaptopropionato, 2-mercaptoacetato and their derivatives

Cobalt(III) complexes with a thiolate or thioether ligand, t-[Co(mp)(tren)]⁺ (2), t-[Co(mtp)(tren)]²⁺ (1Me) and t-[Co(mta)(tren)]²⁺ (2Me), (mp = 3-mercaptopropionate, MA = 3-(methylthio)propionate and MTA = 2-(methylthio)acetate) have been prepared in aqueous solutions. The crystal structures of 1, 2, 1Me and 2Me were determined by X-ray diffraction methods. The crystal data are as follows, t-[Co(mp)(tren)]ClO₄ (1CIO₄): monoclinic, P2₁/n, A = 10.877(8), B = 11.570(4), c = 12.173(7) Å, β = 92.20(5)°, V = 1531(1) ų, Z = 4 and R = 0.060; t-[Co(ma)(tren)]Cl·3H₂O (2Cl·3H₂O): monoclinic, P2₁/n, a = 7.7688(8), B = 27.128(2), C = 7.858(1) Å, β = 100.63(1)°, V = 1627.7(3) ų, Z = 4 and R = 0.066; (+)₄₆₅^CD-t-[Co(mtp)(tren)](ClO₄)₂ ((+)₄₆₅^CD-1Me(ClO₄)₂): orthorhombic, P2₁2₁2₁, A = 10.6610(7), B = 11.746(1), C = 15.555(1) Å, V = 1947.9(3) ų, Z = 4 and R = 0.068; (+)₄₆₅^CD-t-[Co(mta)(tren)](ClO₄)₂ ((+)₄₆₅^CD-2Me(ClO₄)₂): orthorhombic, P2₁2₁2₁, a = 10.564(1), B = 11.375(1), C = 15.434(2) Å, V = 1854.7(4) ų, Z = 4 and R = 0.047. All central Co(III) atoms have approximately octahedral geometry, coordinated by four N, one O, and one S atoms. All of the complexes are only isomer, of which the sulfur atom in the didentate-O,S ligands are located at the trans position to the tertiary amine nitrogen atom of tren. 1 and 1Me contain six-membered chelate ring, and 2 and 2Me do five-membered chelate ring in the didentate ligand. The chirality of the asymmetric sulfur donor atom in (+)₄₆₅^CD-1Me is the S configuration and that in (+)₄₆₅^CD-2Me is the R one. The ¹H NMR, ¹³C NMR and electronic absorption spectral behaviors and electrochemical properties of the present complexes are discussed in relation to their stereochemistries.     

光化学反射指数在比较葡萄叶片耐霜冻能力中的应用

以12个葡萄(Vitis vinifera)品种为试材,在秋季采集叶片,进行霜冻处理,测定了霜冻过程中叶片光化学反射指数(PRI)的变化。提取有效参数,采用隶属函数法比较了不同叶片的耐霜冻能力。结果表明,随着温度的降低,叶片光化学反射指数呈下降趋势。在–8–0°C范围内,PRI及其相对值Rt与温度都存在显著的线性关系;叶片PRI在0°C、–8°C时的相对值R0、R–8,以及–8–0°C范围中,Rt与温度的回归直线斜率SLP都具有品种特异性,可以反映不同品种的耐霜冻能力。隶属函数法结合聚类分析结果显示,在12个候选品种中,抗霜冻能力最好的是Cabernet Sauvignon,其R0、R–8和SLP分别为72.3%、50.19%和2.78。