Pressure dependence on electronic structures,charge distribution and bond orders of solid nitromethane using nonlocal DFT functional

The electronic properties of solid nitromethane are studied using nonlocal exchange-correlation functional (optPBE–vdW) under hydrostatic compression up to 40?GPa. We found that the optPBE–vdW functional can reproduce well the crystalline structures compared with the experiments, and an isomorphic phase transition has been verified by their P–V curve. Bader’s charge analysis shows the electron flows from CH₃ group to NO₂ group with the pressure. Moreover, the calculated bond orders show that the pressure only strengthens the intermolecular C–N bond and intermolecular C–H···O hydrogen bonds though it shortens all bond lengths. Furthermore, the electronic structure and its pressure dependence have also been discussed in detail.     

Effects of shape,size, and pyrene doping on electronic properties of graphene nanoflakes

Effects of size, shape, and pyrene doping on electronic properties of graphene nanoflakes (GNFs) were theoretically investigated using density functional theory method with PBE, B3PW91, and M06-2X functionals and cc-pVDZ basis set. Two shapes of zigzag GNFs, hexagonal (HGN) and rhomboidal (RGN), were considered. The energy band gap of GNF depends on shape and decreases with size. The HGN has larger band gap energy (1.23–3.96 eV) than the RGN (0.13–2.12 eV). The doping of pyrene and pyrene derivatives on both HGN and RGN was also studied. The adsorption energy of pyrene and pyrene derivatives on GNF does not depend on the shape of GNFs with energies between 21 and 27 kcal mol^?1. The substituent on pyrene enhances the binding to GNF but the strength does not depend on electron withdrawing or donating capability. The doping by pyrene and pyrene derivatives also shifts the HOMO and LUMO energies of GNFs. Both positive (destabilizing) and negative (stabilizing) shifts on HOMO and LUMO of GNFs were seen. The direction and magnitude of the shift do not follow the electron withdrawing and donating capability of pyrene substituents. However, only a slight shift was observed for doped RGN. A shift of 0.19 eV was noticed for HOMO of HGN doped with 1-aminopyrene (pyNH₂) and of 0.04 eV for LUMO of HGN doped with 1-pyrenecarboxylic acid (pyCOOH).

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Graphical Abstract HOMO and LUMO Energies of pyrene/pyrene derivatives doped Graphene Nanoflakes

     

Effects of different batches of iodine on properties of I-hFSH and characteristics of radioligand-receptor assays

Radioiodination of highly purified human follicle-stimulating hormone (hFSH) (4000 IU/mg) was performed every other week for 23 weeks using 2 mCi carrier free Na ¹²⁵I (Amersham Corp., 15 mCi/μg I₂) in the presence of lactoperoxidase. Incorporation of ¹²⁵I into hFSH was determined by the method of [7.]Biochem. J. 89, 114). Hormone binding was studied in vitro under steady-state conditions (16 h, 20°C) using different calf testis membrane preparations having similar receptor characteristics. Each ¹²⁵I-hFSH preparation was characterized for maximum bindability, specific activity of bindable radioligand as determined by self-displacement analysis, and by determination of K_a and R_t. Incorporation of ¹²⁵I into FSH was relatively constant over the large number of experiments (62.4 ± 6.4 μCi/μg; n = 23). By comparison, however, specific radioactivity of the receptor bindable fraction of ¹²⁵I-hFSH was related to the lot of ¹²⁵I utilized, and was significantly (P ≤ 0.01) lower and more variable (28.7 ± 10.5 μCi/μg). Maximum bindability of ¹²⁵I-hFSH was not correlated to specific activity (r = 0.06) but was negatively correlated to hFSH ¹²⁵I incorporation (r = −0.47; P ≤ 0.05). These observations demonstrate the need to assess the quality of each batch of radioligand before undertaking radioligand-receptor assays and suggest that differences in Na¹²⁵I lots affect specific radioactivity of the radioligand and its receptor binding characteristics.     

Substituent effects on the electronic structures and nonlinear optical properties of Li-doped nano-carbon bowl

A series of Li-corannulene-(NH₂)_n and Li-corannulene-(NO₂)_n (n = 1, 2, 5) compounds have been theoretically designed and investigated using density functional theory. In this work, two models are systematically investigated to explore the important factors for enhancing the static first hyperpolarizability by introducing the substitution group. It is revealed that energy gaps (E_gap) between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of all compounds are in the range of 4.149–4.934 eV. Different DFT methods are adopted to calculate polarizabilities and the first hyperpolarizabilities of Li-corannulene-(NH₂)_n and Li-corannulene-(NO₂)_n (n = 1, 2, 5) compounds. It is revealed that polarizability values of the systems increase with increasing number of NH₂/NO₂ substitution group. Moreover, it is found that the first hyperpolarizabilities of Li-corannulene-(NO₂)_n are larger than those of Li-corannulene-(NH₂)_n, which can be attributed to the lower transition energies. In contrast to the NH₂ substitution group, NO₂ substitution group can be more powerful in increasing the first hyperpolarizability of Li-doped corannulene. We hope that this study can provide a new idea for designing nonlinear optical materials using the NH₂ and NO₂ groups.     

Effects of abasic sites on structural,thermodynamic and kinetic properties of quadruplex structures

Abasic sites represent the most frequent lesion in DNA. Since several events generating abasic sites concern guanines, this damage is particularly important in quadruplex forming G-rich sequences, many of which are believed to be involved in several biological roles. However, the effects of abasic sites in sequences forming quadruplexes have been poorly studied. Here, we investigated the effects of abasic site mimics on structural, thermodynamic and kinetic properties of parallel quadruplexes. Investigation concerned five oligodeoxynucleotides based on the sequence d(TGGGGGT), in which all guanines have been replaced, one at a time, by an abasic site mimic (dS). All sequences preserve their ability to form quadruplexes; however, both spectroscopic and kinetic experiments point to sequence-dependent different effects on the structural flexibility and stability. Sequences d(TSGGGGT) and d(TGGGGST) form quite stable quadruplexes; however, for the other sequences, the introduction of the dS in proximity of the 3′-end decreases the stability more considerably than the 5′-end. Noteworthy, sequence d(TGSGGGT) forms a quadruplex where dS does not hamper the stacking between the G-tetrads adjacent to it. These results strongly argue for the central role of apurinic/apyrimidinic site damages and they encourage the production of further studies to better delineate the consequences of their presence in the biological relevant regions of the genome.     

Effects of different batches of 125iodine on properties of 125I-hFSH and characteristics of radioligand-receptor assays

Radioiodination of highly purified human follicle-stimulating hormone (hFSH) (4000 IU/mg) was performed every other week for 23 weeks using 2 mCI carrier free Na125I (Amersham Corp., 15 mCi/micrograms I2) in the presence of lactoperoxidase. Incorporation of 125I into hFSH was determined by the method of R. C. Greenwood, W. M. Hunter, and J. S. Grover (1963) Biochem. J. 89, 114). Hormone binding was studied in vitro under steady-state conditions (16 h, 20 degrees C) using different calf testis membrane preparations having similar receptor characteristics. Each 125I-hFSH preparation was characterized for maximum bindability, specific activity of bindable radioligand as determined by self-displacement analysis, and by determination of Ka and Rt. Incorporation of 125I into FSH was relatively constant over the large number of experiments (62.4 +/- 6.4 microCi/micrograms; n = 23). By comparison, however, specific radioactivity of the receptor bindable fraction of 125I-hFSH was related to the lot of 125I utilized, and was significantly (P less than or equal to 0.01) lower and more variable (28.7 +/- 10.5 microCi/micrograms). Maximum bindability of 125I-hFSH was not correlated to specific activity (r = 0.06) but was negatively correlated to hFSH 125I incorporation (r = -0.47; P less than or equal to 0.05). These observations demonstrate the need to assess the quality of each batch of radioligand before undertaking radioligand-receptor assays and suggest that differences in Na125I lots affect specific radioactivity of the radioligand and its receptor binding characteristics.     

Effect of annealing temperature and dopant concentration on the thermoluminescence sensitivity in LiF:Mg,Cu,Ag material

LiF:Mg,Cu,Ag is a new dosimetry material that is similar to LiF:Mg,Cu,P in terms of dosimetric properties. The effect of the annealing temperature in the range of 200 to 350°C on the thermoluminescence (TL) sensitivity and the glow curve structure of this material at different concentrations of silver (Ag) was investigated. It has been demonstrated that the optimum values of the annealing temperature and the Ag concentration are 240°C and 0.1 mol% for better sensitivity, respectively. The TL intensity decreases at annealing temperatures lower than 240°C or higher than 240°C, reaching a minimum at 300°C and then again increases for various Ag concentrations. It was observed that the glow curve structure altered and the area under the low temperature peak as well as the area under the main dosimetric peak decreased with increasing annealing temperature. The position of the main dosimetric peak moved in the direction of higher temperatures, but at 320 and 350°C annealing temperatures, it shifted to lower temperatures. It was also observed that the TL sensitivity could partially be recovered by a combined annealing procedure.     

外源钙对不同钙敏感型番茄幼苗生理特性的影响

利用钙不敏感型番茄品种(江蔬1号)和钙敏感型番茄品种(L-402)为试材,研究了不同浓度的外源钙对其根系活力、钙调素含量、叶绿素a、b含量和比值及活性氧清除酶系统活性的影响.结果表明,根系钙调素(CaM)含量随介质钙浓度增加而增加,不敏感品种江蔬1号高于敏感品种L-402.根系活力、生长点和真叶chla/b比值在低钙强度下(1和4 mg·L^-1)以江蔬1号显著高于L-402,在充足供钙时(100 mg·L^-1)L-402显著高于江蔬1号,表明江蔬1号品种具有较强的耐低钙和光胁迫的能力.对活性氧清除酶系统活性来说,在三个钙浓度下敏感品种L-402的POD、CAT酶活性均显著高于江蔬1号,降钙使两酶活性升高,SOD酶活性下降,且L-402下降的幅度高于江蔬1号,表明低钙造成的胁迫对L-402品种影响较大,江蔬1号较耐受缺钙胁迫.     

Comparative study on electronic structures and optical properties of indoline and triphenylamine dye sensitizers for solar cells

The computations of the geometries, electronic structures, dipole moments and polarizabilities for indoline and triphenylamine (TPA) based dye sensitizers, including D102, D131, D149, D205, TPAR1, TPAR2, TPAR4, and TPAR5, were performed using density functional theory, and the electronic absorption properties were investigated via time-dependent density functional theory with polarizable continuum model for solvent effects. The population analysis indicates that the donating electron capability of TPA is better than that of indoline group. The reduction driving forces for the oxidized D131 and TPAR1 are slightly larger than that of other dyes because of their lower highest occupied molecular orbital level. The absorption properties and molecular orbital analysis suggest that the TPA and 4-(2,2diphenylethenyl)phenyl substituent indoline groups are effective chromophores in intramolecular charge transfer (IMCT), and they play an important role in sensitization of dye-sensitized solar cells (DSCs). The better performance of D205 in DSCs results from more IMCT excited states with larger oscillator strength and higher light harvesting efficiency. While for TPA dyes, the longer conjugate bridges generate the larger oscillator strength and light harvesting efficiency, and the TPAR1 and TPAR4 have larger free energy change for electron injection and dye regeneration.     

不同覆盖物对烤烟根温及生长和生理特性的影响

分别以大棚膜、稻草+大棚膜、普通膜、稻草、稻草+遮阳网和遮阳网为覆盖材料,研究覆盖物对烤烟根温以及生长和生理特性的影响.结果表明,各覆盖处理22 d对5和15 cm土壤总积温的影响明显不同,5 cm土壤总积温最高为大棚膜处理（424.75 ℃）,最低为稻草+遮阳网处理（378.75 ℃）,22 d 的15 cm土壤总积温最高为大棚膜处理（396.75 ℃）,最低为遮阳网处理（368.31 ℃）.随着土壤总积温的升高,烟株地上部和地下部干重都呈增长趋势,光合作用增强,根系活力提高;揭膜后第10天烟株根系干重有所增加,普通地膜处理的根系生物量增加最多,稻草+遮阳网处理最少.     

Photophysical properties, electronic and crystal structures of luminescent diphosphine digold(I)-pyridine-2-thiolate complexes

Treatment of diphosphine digold(I) complexes, PP(AuCl)₂ [PP=bis(diphenylphosphino)methane, dppm; 1,6-bis(diphenylphosphino)hexane, dpph], with two equivalents of pyridine-2-thiol (HNS) in the presence of NaOCH₃ affords two luminescent diphosphine digold(I)-pyridine-2-thiolate complexes, dppm(AuSN)₂ (1) and dpph(AuSN)₂ (2), respectively. Both crystal structures have been determined by crystallographic studies. The intramolecular aurophilic contact of 3.0478(3) Å is observed in the crystal structure of 1, whereas there is not any aurophilic interaction present in the crystal lattices of 2. At room temperature, 1 shows a low-energy emission at ca. 660 nm as well as a very weak high-energy emission at ca. 496 nm in the solid state, but 2 shows only a strong high-energy one at ca. 482 nm. Thus, the emission energy strongly dependent on the Au(I)?Au(I) interaction can be demonstrated in the diphosphine digold(I) thiolates studied herein.     

Leaf characteristics and optical properties of different woody species

 Light partition has been examined and evaluated on five woody species (Olea europaea, Ficus carica, Pittosporum tobira, Hedera helix maculata, Persica vulgaris) in relation to their leaf morpho-histological characteristics, water and chlorophyll contents. Leaf parameters and optical properties (reflectance, transmittance, absorbance) in PAR, FR and NIR wavebands (400–1100 nm) were preliminarily submitted to a canonical correlation analysis where lamina thickness and water content showed a leading role in determining all the optical properties, while chlorophyll, influential in the PAR region, was remarkably effective only in an extreme pigment situation when green and albino patches of ivy leaves were compared. Transmittance appeared inversely related to lamina thickness in accordance with the Lambert Beer law. Significant correlations were found also between mesophyll water content and both transmittance (positive) and reflectance (negative). Olive leaves showed peculiar optical patterns because of the dense and continuous trichome layer on their abaxial surface. Received: 3 January 1997 / Accepted: 5 May 1997     

Ultraconserved elements: analyses of dosage sensitivity, motifs and boundaries

Ultraconserved elements (UCEs) are sequences that are identical between reference genomes of distantly related species. As they are under negative selection and enriched near or in specific classes of genes, one explanation for their ultraconservation may be their involvement in important functions. Indeed, many UCEs can drive tissue-specific gene expression. We have demonstrated that nonexonic UCEs are depleted among segmental duplications (SDs) and copy number variants (CNVs) and proposed that their ultraconservation may reflect a mechanism of copy counting via comparison. Here, we report that nonexonic UCEs are also depleted among 10 of 11 recent genomewide data sets of human CNVs, including 3 obtained with strategies permitting greater precision in determining the extents of CNVs. We further present observations suggesting that nonexonic UCEs per se may contribute to this depletion and that their apparent dosage sensitivity was in effect when they became fixed in the last common ancestor of mammals, birds, and reptiles, consistent with dosage sensitivity contributing to ultraconservation. Finally, in searching for the mechanism(s) underlying the function of nonexonic UCEs, we have found that they are enriched in TAATTA, which is also the recognition sequence for the homeodomain DNA-binding module, and bounded by a change in A + T frequency.     

Effects of different exercise modes on mineralization, structure, and biomechanical properties of growing bone.

Weight bearing during exercise plays an important role in improving the mechanical properties of bone. The effect on bone of non-weight-bearing exercise such as swimming remains controversial. To investigate the effects of exercise mode on growing bone, 29 male Wistar rats (7 wk old) were randomly assigned to a running exercise group (Run, n = 9), a swimming exercise group (Swim, n = 10), or a nonexercise control group (Con, n = 10). During an 8-wk training session (20-60 min/day, 5 days/wk), the Run rats were trained at progressively increasing running speeds (12-22 m/min), and weights attached to the tail of the Swim rats were progressively increased from 0 to 2% of their body weight. The bone mineral density of the proximal tibiae of the Run rats was significantly higher than in the Swim (P < 0.05). Femoral wet weights of the two exercise groups were significantly higher than in the control group (P < 0.05). Interestingly, the percent difference between the tissue wet weight and dry weight (water content ratio), which is related to bone mechanical properties, was significantly higher in the tibiae of the Swim rats and the femora of both exercise groups compared with controls (P < 0.05). Extrinsic as well as intrinsic biomechanical material properties were measured in a three-point bending test. Bone mechanical properties of the tibiae and femora of rats in the Swim and Run groups were significantly greater than those in the control group (P < 0.05). In summary, different modes of exercise may benefit bone mechanical properties in different ways. The specific effects of swimming exercise (non-weight-bearing exercise) on bone require further study.     

不同光质补光对火龙果茎生理特性及开花结果的影响

为探究不同光质补光对火龙果茎生理特性的影响,该文采用红光、白光、蓝光3种不同光质对火龙果进行夜间补光,测定火龙果茎中可溶性糖、可溶性蛋白、叶绿素、线粒体蛋白、线粒体膜电位及细胞分裂素(CTK)、吲哚乙酸(IAA)、赤霉素(GA)3种内源激素的含量,并统计茎长、开花数、果实产量相关指标.结果表明:3种光质补光均可提高火龙...     

不同光质LED光源对草莓光合特性、产量及品质的影响

以‘妙香7号’草莓品种为材料,利用LED精量调制光源,设红光、蓝光、黄光、白光、红/蓝/黄(7/2/1)、红/蓝(7/2) 5个处理,以白光为对照,测定了草莓叶片的光合与荧光参数、色素含量、果实产量、品质和根系活力指标,研究 500 μmol·m^-2·s^-1光强下不同光质处理对草莓光合特性、果实产量及品质的影响.结果表明： 红光处理有利于提高草莓叶片的净光合速率与蒸腾速率,而蓝光有减弱作用;气孔导度与胞间CO₂浓度均以蓝光处理效果最为显著.叶绿素荧光参数(F_o、F_m、Φ_PSⅡ)均在红光处理下最大,而F_v/F_m、F_v/F_o、F_m/F_o均在红/蓝/黄处理下最大;红/蓝/黄处理下草莓色素含量、果实产量和根系活力均显著高于其他处理.红光处理的可溶性固形物和维生素C含量均最高,且与红/蓝/黄处理差异不显著;蓝光处理有利于提高可滴定酸和蛋白质含量,而红/蓝/黄处理的固酸比最大.红/蓝/黄处理最有利于增加光合色素含量,提高果实产量,促进部分品质改善.     

Effects of biomotor structures on performance of competitive gymnastics elements in elementary school female sixth-graders

In order to identify biomotor systems that determine performance of competitive gymnastics elements in elementary school female sixth-graders, factor structures of morphological characteristics and basic motor abilities were determined first, followed by relations of the morphological-motor system factors obtained with a set of criterion variables evaluating specific motor skills in competitive gymnastics in 126 female children aged 12 years +/- 3 months. Factor analysis of 17 morphological measures yielded three morphological factors: factor of mesoendomorphy and/or adipose body voluminosity; factor of longitudinal body dimensionality; and factor of transverse arm dimensionality. Factor analysis of 16 motor variables produced four motor factors: general motoricity factor (motor system); general speed factor; factor of explosive strength of throwing type (arm explosiveness); and factor of arm and leg flexibility. Three significant canonical correlations, i.e. linear combinations, explained the association between the set of seven latent variables of the morphological and basic motor system, and five variables evaluating the knowledge in competitive gymnastics. The first canonical linear combination was based on a favorable and predominant impact of the general motor factor (a system integrating whole body coordination, leg explosiveness, relative arm strength, arm movement frequency and body flexibility) on performance of gymnastics elements, cartwheel, handstand and backward pullover mount in particular, and to a lesser extent front scale and double leg pirouette for 180 degrees. The relation of the second pair of canonical factors additionally explained the role of transverse dimensionality of arm skeleton, arm flexibility and explosiveness in performing cartwheel and squat vault, whereas the relation of the third pair of canonical factors explained the unfavorable impact of adipose voluminosity on the performance of squat vault and backward pullover mount.     

遮光对不同基因型玉米光合特性的影响

采用盆栽试验,研究了遮光对4个基因型玉米光合特性的影响.结果表明:4个基因型玉米叶片的光饱和点、净光合速率(Pn)、电子传递速率(ETR)、光系统Ⅱ最大光化学效率(Fv/Fm)和实际光化学效率(ΦPSⅡ)均受光强的影响.遮光降低了玉米的光饱和点,苗期遮光处理豫玉2号和丹玉13分别在光量子通量密度(PFD)为1400μmol·m-2·s-1和1100μmol·m-2·s-1时达到饱和.遮光还降低了玉米的Pn、ETR、Fv/Fm和ΦPSⅡ,但不同基因型玉米表现不同,豫玉2号和掖单22的下降幅度较小,而丹玉13和掖单6号的下降幅度较大.     

Effects of biomotor structures on performance of competitive gymnastics elements in elementary school male sixth-graders

In order to identify the biomotor systems that determine performance of competitive gymnastics elements in elementary school male sixth-graders, factor structures of morphological characteristics and basic motor abilities were determined first, followed by relations of the morphological-motor system factors obtained with a set of criterion variables evaluating specific motor skills in competitive gymnastics in 110 male children aged 12 years +/- 3 months. Factor analysis of 17 morphological measures produced three morphological factors: factor of mesoectoendomorphy (general morphological factor) and factor of pronounced endomorphy, i.e. excessive adipose tissue, along with low skeleton longitudinality. Factor analysis of 16 motor variables yielded four motor factors: factor of general motoricity; factor integrating leg flexibility and arm explosiveness; factor juxtaposing body flexibility and repetitive leg strength; and factor predominantly defining leg movement frequency. Three significant canonical correlations, i.e. linear combinations, explained the association between the set of six latent variables of the morphological and basic motor system, and five variables assessing the knowledge in competitive gymnastics. The first canonical linear combination was based on the favorable and predominant impact of the general motor factor (a system integrating leg explosiveness, whole body coordination, relative arm and trunk strength, and arm movement frequency), along with unfavorable effect of morphological factors on the gymnastics elements performance, squat vault and handstand in particular The relation of the second pair of canonical factors pointed to the effects of leg flexibility and arm explosiveness on the cartwheel and backward pullover mount performance, whereas the relation of the third pair of canonical factors showed a favorable impact of the general morphological factor and leg movement frequency regulator on the forward shoulderkip from increase, cartwheel and handstand performance.