基于单调链的Red/Blue扫描线求交算法

提出了一种基于单调链的Red/Blue平面扫描线算法。该算法针对GIS中线段之间具有连接关系的特性,将平面连接线段集分解为一组单调链,通过对单调链的粗扫描过滤和对线段的精扫描求交,减少了扫描过程中的冗余计算,提高了线段集求交点的效率。实验证明,该算法对于处理具有连接关系的线段集的求交点问题具有很高的效率。

Transcriptome analysis reveals effects of red and blue lightemitting diodes(LEDs)on the growth,chlorophyll fluorescence and endogenous plant hormones of potato(Solanum tuberosum L.)plantlets cultured in vitro

Red and blue light illumination has been reported to significantly affect plantlet growth.Potato is an important food and feed crop in the world and potato plantlet cultured in vitro plays an important role in potato production.However,few studies have documented the effects of red and blue light on the growth of potato plantlets revealed at the transcriptome level.The objective of this study was to determine the growth and physiological responses of potato plantlets cultured in vitro under monochromatic red(RR),monochromatic blue(BB)as well as combined red and blue(RB)LEDs using the RNA-Seq technique.In total,3150 and 814 differentially expressed genes(DEGs)were detected in potato plantlets under RR and BB,respectively,compared to RB(used as control).Compared to the control,the DEGs enriched in"photosynthesis"and"photosynthesis-antenna proteins"metabolic pathways were up-regulated and down-regulated by BB and RR,respectively,which might be responsible for the increases and decreases of maximum quantum yield(F_(v)/F_(m)),photochemical quantum yield(φ_(PSII)),photochemical quenching(q_(P))and electron transfer rate(ETR)in BB and RR,respectively.Potato plantlets exhibited dwarfed stems and extended leaves under BB,whereas elongated stems and small leaves were induced under RR.These dramatically altered plantlet phenotypes were associated with variable levels of endogenous plant hormones gibberellin(GAs),indoleacetic acid(IAA)and cytokinins(CKs),as assessed in stems and leaves of potato plantlets.In addition,monochromatic red and blue LEDs trigged the opposite expression profiles of DEGs identified in the"plant hormone signal transduction"metabolic pathway,which were closely related to the endogenous plant hormone levels in potato plantlets.Our results provide insights into the responses of potato plantlets cultured in vitro to red and blue LEDs at the transcriptomic level and may contribute to improvements in the micro-propagation of potato plantlets cultured in vitro from the light spectrum aspect.

Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm(Rhodophyta),and effects of red and blue light on repair of UV-B-induced damage

We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.

Measurement and Correlation of Solubilities of C.I. Disperse Red 73,C.I. Disperse Blue 183 and Their Mixture in Supercritical Carbon Dioxide

The solubility of disperse dyes and their mixture in supercritical carbon dioxide is an important property in study and development of supercritical fluid dyeing technology.In this study,solubilities of C.I.Disperse Red 73,C.I.Disperse Blue 183 and their mixture in supercritical CO2 are measured at temperatures from 343.2 to 383.2 K and pressures from 12 to 28 MPa with a static recirculation method.Under the experimental conditions for the binary(C.I.Disperse Red 73+CO2 or C.I.Disperse Blue 183+CO2) and ternary(C.I.Disperse Red 73+C.I.Disperse Blue 183+CO2) systems,the solubilities increase with pressure.The solubility of C.I.Disperse Blue 183 decreases with the increase of temperature when the pressure is lower than 16 MPa,and the trend is opposite when the pressure is higher than 16 MPa.However,there is no crossover pressure for C.I.Disperse Red 73.The solubilities are also affected by molecular polarity of dyes.The co-solvent effect exhibited in the dissolving process of mixed dyes promotes their dissolution in supercritical CO2.The experimental data of solubilities of C.I.Disperse Red 73,C.I.Disperse Blue 183,and their mixture are correlated with the Chrastil model and Mendez-Santiago/Teja model. The former is more accurate.

Supplemental blue and red light promote lycopene synthesis in tomato fruits

Lycopene, one of the strongest natural antioxidants known and the main carotene in ripe tomato, is very important for human health. Light is well known to be one of the most important environmental stimuli influencing lycopene biosynthesis; specifically, red light induces higher lycopene content in tomato. However, whether blue light promotes lycopene synthesis remains elusive and exactly how light stimulation promotes lycopene synthesis remains unclear. We applied supplemental blue and red lighting on tomato plants at anthesis to monitor the effect of supplemental blue and red lighting on lycopene synthesis. Our results showed that supplemental blue/red lighting induced higher lycopene content in tomato fruits; furthermore, we found that the expression of key genes in the lycopene synthesis pathway was induced by supplemented blue/red light. The expression of light signaling components, such as red-light receptor phytochromes(PHYs), blue-light receptor cryptochromes(CRYs) and light interaction factors, phytochrome-interacting factors(PIFs) and ELONGATED HYPOCOTYL 5(HY5) were up-or down-regulated by blue/red lighting. Thus, blue and red light increased lycopene content in tomatoes by inducing light receptors that modulate HY5 and PIFs activation to mediate phytoene synthase 1(PSY1) gene expression. These results provide a sound theoretical basis for further elucidation of the light regulating mechanism of lycopene synthesis in tomatoes, and for instituting a new generation of technological innovations for the enhancement of lycopene accumulation in crop production.

Effects of Different Combinations of Red and Blue Light on Morphology and Photosynthetic Characteristic of Tomato Seedlings

Blue and red light are spectral wavelengths more effective for plants. The effects of different ratios of red and blue light （R/B=2, R/B=4, R/B=8, R/B=12） provided by LEDs on morphology and photosynthetic characteristics of tomato seedlings were studied. The results showed that plant height, stem diameter, fresh weight, dry weight, seedling index and G value increased with the increase of R/B ratio until 8. On the contrary, SPDA value decreased with the increase of R/B ratio. Photosynthetic characteristics were measured by CO 2 assimilation （ Pn ）, stomatal conductance （ gs ） and intracellular CO 2 concentration （ Ci） . Pn and gs decreased with the increase of R/B ratio. Furthermore, similar trend was investigated in photochemical quenching （qP） and electron transport rate （ETR）. Results of this study suggest that compared with white LED, appropriate combination of red and blue light can enhance plant growth and photosynthetic characteristics, and the optimal blue/red ratio for tomato growth was R/B=8.

电解法处理C.I. Reactive Red 241、C.I. Disperse Blue 56模拟染料废水的研究

以C.I.Reactive Red 241、C.I.Disperse Blue 56模拟染料废水为对象,研究了电解法处理该类染料废水的优化条件。考察了起始电压、电解时间、溶液初始p H对处理效果的影响。结果表明,在p H=7,U=14V、I=3.2A、t=30min的条件下,C.I.Reactive Red241模拟染料废水的脱色率可达到86%以上;在p H=7,U=14V、I=3.2A、t=25min的条件下,C.I.Disperse Blue 56模拟染料废水的脱色率可达到79以上%。

Transcriptome analysis of carotenoid biosynthesis in Dunaliella salina under red and blue light

The quality of light is an important abiotic factor that affects the growth and development of photosynthetic organisms.In this study,we exposed the unicellular green alga Dunaliella salina to red(660 nm)and blue(450 nm)light and analyzed the cell growth,total carotenoid content,and transcriptomes.The growth of D.salina was enhanced by illumination with red light,whereas blue light was not able to promote the algal growth.In contrast,the total carotenoid content increased under both red and blue light.The RNA of D.salina was sequenced and the transcriptomic response of algal cells to red and blue light was investigated.Six transcripts encoding for the blue light receptor cryptochrome were identified,and transcripts involved in the carotenoid metabolism were up-regulated under both red and blue light.Transcripts encoding for photoprotective enzymes related to the scavenging of reactive oxygen species were up-regulated under blue light.The present transcriptomic study provides a more comprehensive understanding of carotenoid biosynthesis in D.salina under different wavelengths of light.

Determination of Surface Area of Red Mud and Beringite Using Methylene Blue Method

The adsorption of methylene blue (MB) on three soil amendments, red mud from Hungary, red mudfrom UK and beringite from Belgium, was studied to determine the surface areas of the amendments usinga 0.005 mol L-1 NaCl solution and deionised water as background solutions. The surface areas determinedby the methylene blue method in the 0.005 mol L-1 NaCl solution were 3.357, 2.340 and 5.576 m2 g-1 forred mud (Hungary), red mud (UK) and beringite, respectively slightly lower than those in the deionisedwater system. The largest surface area of beringite suggested that the MB could adsorb effectively on theinterlayer surface of illite. The effect of NaCl on the surface areas was relatively small and may therefore beignored. Both the 0.005 mol L-1 NaCl solution and deionised water could be used as a background solutionfor measurement of surface area of oxide-rich materials.

Vermicompost for Indigo Blue and Congo Red Removal

The data obtained through this work revealed that the vermicompost is a natural adsorbent able to removal two textile dyes from an aqueous medium. The values of maximum adsorption capacity for congo red (23.25 mg/g) and indigo blue (40.39 mg/g) obtained from the Mathematical Langmuir Model reveal it. The conditions of adsorbent mass, stirring time between adsorbent and dyes were optimized. Additionally, the values of Gibbs free energy demonstrate the predominance of physical interaction between both dyes and vermicompost. Through Langmuir constant values, it was possible to identify similar affinities between both dyes and vermicompost. The value of dimensionless constant indicates favorable adsorptions process. Finally, through physicochemical analysis from scanning electron microscopy and Fourier Transform Infra-Red Spectroscopy, the characteristics of vermicompost were verified revealing essential aspects to efficient adsorbent.

Blue-Red Tuning Emission of ZnO: Europium Quantum Dots with Different Excitation Wavelengths

Optoelectronic applications require the development of new fluorescent and efficient luminescent materials, free of toxicity, low in cost, and easy to produce. In this way the synthesis of zinc-oxide (ZnO) quantum dots (QDs) has recently received special attention due to their good optical, electrical and chemical properties with low production costs and blue light emission. In this work ZnO QDs were successfully doped with europium in order to obtain a tunable emission luminescence from blue emission of ZnO to red emission of europium as a function of wavelength excitation. Results show an efficient blue to red tuning when the excitation wavelength was changed from 317 nm to 395 nm, respectively. This opens the possibility of having new optical devices to produce different color emission using the same material.

不同波长LEDs光源对苦荞芽菜生长、生物活性物积累及抗氧化活性的影响

为探究不同波长LEDs光源对苦荞芽菜生长的影响,本研究以黑暗(D)作对照,采用单色红(R)、蓝(B)、绿(G)光源培养苦荞芽菜,收获后分别测定其形态指标、生物活性物积累量、类黄酮合成关键基因表达量及抗氧化活性指标,结果表明:B处理的苦荞芽菜下胚轴呈深红色,伸长生长受到强烈抑制,花青素、总黄酮及总酚积累量均最高,分别是D的7.18、2.96和2.49倍;R处理的下胚轴呈浅粉色,上述3种生物活性物积累量分别是对照的2.56、1.68和1.40倍;G处理的下胚轴伸长与R相似,外观呈透明白色,生物活性物积累量与对照无显著差异。B和R均强烈诱导类黄酮生物合成通路上关键结构基因表达,显著增加苦荞芽菜下胚轴抗氧化活性。此外,各单色光处理均未显著影响苦荞芽菜可食用部位的鲜重。由此可见,红、蓝LEDs光源可显著影响苦荞芽菜形态生长,并增加其生物活性物积累及抗氧化能力,以蓝光最佳。

光质对银杏苗木生长及黄酮类化合物积累的影响

【目的】探究红、蓝光质对银杏苗木生长及黄酮类化合物积累的影响。【方法】以1年生银杏苗为材料,设置红光、蓝光、红蓝混光3种光质,并以白光作为对照(CK),在处理的第3、6、9、12周分别测定银杏苗的黄酮含量及单株产量、黄酮合成相关酶活性和黄酮总还原力,并在第12周测定其生长指标。【结果】光质处理下,银杏苗木的总生物量均低于CK,苗高在蓝光处理下显著提高,地径受光质影响较小。黄酮合成相关酶中,苯丙氨酸解氨酶(PAL)和肉桂酸4-羟化酶(C4H)的活性在混光和蓝光处理下提高,而4-香豆酸辅酶A连接酶(4CL)活性仅在红光处理下提高。光质极显著影响黄酮类化合物(槲皮素、山柰酚、异鼠李素、总黄酮)含量、单株黄酮产量及黄酮提取液总还原力,各处理黄酮产量及总还原力均表现为蓝光和混光强于红光和CK,即蓝光和混光有利于黄酮类化合物的积累及抗氧化能力的提高。随着光质处理时间的延长,黄酮类化合物含量的变化趋势总体表现为前期(第3~6周)高于后期(第9~12周),普遍在第6周达到最大值。【结论】混光和蓝光处理可促进银杏苗木黄酮类化合物的积累及相关酶活性,红光则相反;叶用银杏光质处理时间以6周较为适宜。

红蓝光促进陆地棉愈伤组织诱导和增殖

【目的】陆地棉(Gossypium hirsutum)的遗传转化技术存在转化周期长、转化效率低等问题,其中,愈伤组织增殖速度慢是导致棉花转化周期长的关键因素。探究陆地棉愈伤组织增殖的最适光照条件,为缩短棉花转化周期提供技术基础。【方法】以陆地棉受体品种WC的下胚轴为外植体诱导愈伤组织,设置红光、蓝光、红蓝光(1﹕1)和白光(CK)4种不同光照处理,研究不同光质下愈伤组织的增殖速度、形态特征,以及相关基因表达水平和相关酶活性的差异,解析光照对愈伤组织增殖的影响并获得最优光照条件。【结果】不同光质对诱导棉花外植体出愈和愈伤组织生长具有明显影响。在4种不同光照处理下,红蓝光相较其他光质具有更显著地促进外植体出愈和愈伤组织增殖的效果,表现为愈伤组织分化时间更短,7—15 d,即与其他处理存在明显表型差异,7 d愈伤组织鲜重红蓝光(0.39 g)>蓝光(0.34 g)>白光(0.24 g)>红光(0.23 g),15 d时,红蓝光(1.15 g)>蓝光(0.98 g)>白光(0.69 g)>红光(0.51 g),红蓝光照射下的愈伤组织鲜重是白光对照的1.65倍,比单一蓝光或红光照射下的愈伤组织鲜重增加16.5%或125.5%;与此相一致的是,红蓝光处理下,第二周的愈伤增殖率也最高,达14.67%,比红光处理(7.17%)增加1倍多。4种光质下,愈伤增殖及体胚再生相关基因的表达量,红蓝光处理均显示最高。此外,红蓝光处理下愈伤组织的过氧化氢酶(CAT)活性显著提高,活性氧(ROS)含量低于白光对照。【结论】不同光质条件下,棉花外植体的愈伤组织增殖速度不同,红蓝光(1﹕1)促进外植体出愈和愈伤增殖表现最优,其次为蓝光,再次为白光,单独的红光不利于棉花出愈和愈伤增殖。红蓝光(1﹕1)处理诱导光受体及其互作因子、愈伤增殖等相关基因的表达,增强愈伤组织内过氧化氢酶的活性,降低活性氧含量,促进细胞分裂,进而促进愈伤增殖。

铈红与钴蓝对聚乙烯棚膜红/蓝光质调控及性能影响

红/蓝光质调控聚乙烯(PE)棚膜一直以来是农膜行业亟需解决的难题。在PE中引入铈红(CeS)和钴蓝(CoO·Al_(2)O_(3)),通过吹塑工艺制备PE红/蓝光棚膜。光电雾度仪测试结果发现CeS和CoO·Al_(2)O_(3)对PE棚膜的透光率影响较小,但雾度和散光度有所增加;光纤光谱仪和手持式光谱照度仪表征结果显示CeS和CoO·Al_(2)O_(3)明显提升450~520 nm的蓝光和605~700 nm的红光透过率,且CeS与CoO·Al_(2)O_(3)质量比为1∶2时,红光透过率为39.2%,蓝光透过率为38.1%,红/蓝光透过比例为1.03;万能拉伸试验机测试结果发现CeS与CoO·Al_(2)O_(3)可改善PE棚膜的力学性能,其中拉伸强度较空白样提升约5.5%,断裂伸长率提升约16.8%,直角撕裂强度提升约3%,穿刺强度提升约21.8%;差示扫描量热仪表征结果显示添加CeS与CoO·Al_(2)O_(3)可提升PE氧化诱导期(Oit)达45 min以上,PE具有良好的耐热老化性能。上述测试表征结果表明:CeS与CoO·Al_(2)O_(3)的引入可明显提升PE棚膜的散光性能、力学性能、耐热稳定性能、红/蓝光透过率及透过比例。此外,可通过调控CeS与CoO·Al_(2)O_(3)的质量比获得不同红/蓝光质调控的PE功能棚膜。

LED红蓝光配比对番茄生长和光合的影响

以番茄品种‘普罗旺斯’为材料,在双拱钢架日光温室内进行人工补光试验,设置T1(2R3B,即红光/蓝光珠数配比R:B=2:3)、T2(4R1B)、T3(6R1B)、T4(7R1B)四组红蓝光处理,以不进行人工补光为对照(CK),探究温室番茄生长和光合响应最优的红蓝光配比。结果表明,在T1处理下35d后,番茄的株高、SPAD、蒸腾速率(Tr)和光化学淬灭系数(qP)较对照组分别显著提高26.7%、19.6%、107.6%和34.3%。在T3处理下35d后,番茄的茎粗、花朵数、净光合速率(Pn)、胞间CO_(2)浓度(Ci)、气孔导度(Gs)、实际光化学效率(ΦPSⅡ)和电子传输速率(ETR)较对照组分别显著提高26.9%、38.6%、133.7%、5.9%、183.3%、31.3%和30.9%。在T4处理下35d后,最大光化学效率(Fv/Fm)较对照组分别显著提高4.0%。在对设施番茄进行不同配比红蓝光补光处理下,较对照组可显著促进番茄的生长及光合作用,在本试验设置的2R3B、4R1B、6R1B、7R1B四组红蓝组合光处理中,6R1B(红/蓝光珠数配比R:B=6:1)处理下各项指标表现的综合效果最佳,可为温室番茄栽培LED补光提供一定的理论指导。

高压脉冲电场对毛发染色效果的影响

为了研究高压脉冲电场对毛发染色效果的影响,试验以18~28岁年龄段人群的黑色头发和染发剂为试材,以染发后毛发的RGB(red green blue)模型提取值作为响应值,并采用等响应面试验法设计试验,以构建和分析高压脉冲电场的电场强度、脉冲宽度以及脉冲个数对毛发染色效果影响的数学模型和机理。试验结果表明:高压脉冲电场同时处理头发和染发剂后最高可提升RGB参数中的蓝色通道值B为3.7%,对应的最优化工艺化参数为:电场强度1125 V/mm、脉冲宽度175μs、脉冲个数52个。因此,高压脉冲电场对头发和染发剂进行处理后再进行染色可改善着色效果,并为毛发染色工艺优化奠定一定基础。

红蓝光治疗慢性伤口疗效的Meta分析

目的评价红蓝光联合治疗慢性伤口的效果。方法检索PubMed、Embase、Web of Science、Cochrane Library、中国知网、万方、维普、中国生物医学文献数据库(CBM)中关于红蓝光联合辅助慢性伤口治疗的文献,检索时限为2012年1月至2022年7月。由2名研究者独立进行文献筛选、资料提取和质量评价,采用RevMan 5.4软件进行统计分析。结果共纳入10篇文献,累计样本量为710例,Meta分析结果显示:观察组伤口痊愈率高于对照组[OR=2.03,95%CI(1.33~3.11),P=0.001],肉芽组织分级高于对照组[MD=0.95,95%CI(0.18,1.73),P=0.02],创面面积缩小率高于对照组[MD=14.43,95%CI(10.98~17.87),P<0.001],伤口愈合时间低于对照组[MD=-7.16,95%CI(-8.56~-5.74),P<0.001],换药次数低于对照组[MD=-5.44,95%CI(-5.94~-4.95),P<0.001],观察组与对照组伤口附近皮肤评分差异无统计学意义[MD=0.10,95%CI(-0.93~1.12),P=0.85]。结论红蓝光联合使用治疗慢性伤口能有效提高伤口痊愈率、肉芽组织分级及创面面积缩小率,同时能缩短伤口愈合时间,减少换药次,且对伤口附近皮肤无影响。

红蓝光联合系统药物治疗带状疱疹的安全性及有效性分析

目的利用Meta分析观察红蓝光联合系统药物治疗带状疱疹的临床有效性和安全性。方法检索the Cochrane Library、EMbase数据库、Pubmed数据库、中国生物医学文献数据库、CNKI(China national knowledge infrastructure)数据库、维普数据库、万方数据库,纳入红蓝光联合系统药物治疗带状疱疹的随机对照治疗(randomized controlled trial,RCT),并进行方法学质量评价,采用RevMan 5.4软件进行统计分析。结果8篇RCT文献纳入本项研究,累计病例1240例。Meta分析结果显示红蓝光联合系统药物治疗带状疱疹总有效率(OR=4.92,95%CI:2.95~8.21,P<0.00001)、痊愈率(OR=2.17,95%CI:1.66~2.85,P<0.00001)、水疱消退时间(MD=-1.16,95%CI:-1.33~-0.98,P<0.00001)、结痂时间(MD=-1.47,95%CI:-1.80~-1.14,P<0.00001)、疼痛缓解时间(MD=-2.05,95%CI:-2.54~-1.56,P<0.00001)效果明显优于单纯使用基础药物组,差异有统计学意义(P<0.05)。结论红蓝光联合系统药物治疗带状疱疹疗效确切,优于系统药物组,是光电联合药物治疗带状疱疹的有效方法。

蓝膜对西南杨幼苗光合参数及苗木生长的影响

[目的]阐明蓝膜下光质成分对西南杨(Populus schneideri)幼苗生长的影响。[方法]选取1年生西南杨扦插幼苗置于蓝色、白色薄膜制成的拱棚下培育60 d,测定其生长指标、叶片解剖结构、光合参数、光合色素及糖含量。[结果]蓝膜能够促进西南杨幼苗的苗高生长及叶长、叶宽的增加,其苗高、叶长和叶宽分别比白膜增加36.36%、418.52%和495.24%,且两者间差异极显著。与白膜相比,蓝膜处理的叶片上表皮显著变薄;而叶片、栅栏组织、海绵组织和下表皮的厚度仅略微增加。蓝膜处理下,光合气体交换参数蒸腾速率(T_(r))、净光合速率(P_n)、胞间CO_(2)浓度(C_(i))和气孔导度(G_(s))均显著或极显著增加,表明蓝膜处理能够提高西南杨幼苗的光合效率。蓝膜处理的表观量子效率、最大净光合速率、羧化效率和光呼吸速率均极显著高于白膜,而CO_(2)饱和点和CO_(2)补偿点均显著或极显著小于白膜,表明蓝膜处理使得西南杨幼苗对弱光有较好的适应性,但对高浓度CO_(2)环境适应能力较弱。蓝膜处理的叶绿素a、叶绿素b、淀粉和还原性糖含量分别比白膜高22.69%、41.18%、65.85%和54.26%,而蔗糖含量显著低于白膜。[结论]西南杨幼苗对高比例蓝光有较强的适应性,蓝膜可促进西南杨幼苗的苗高生长,并通过增加叶片G_(s)、叶绿素含量、RubisCO活性及含量等促进植株的光合作用。研究结果为解析西南杨适应高比例短波光的机制提供了研究基础,也为西南杨引种栽培光质条件的选择与优化提供了科学依据。