mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Seasonal variation and source apportionment of organic and inorganic compounds in PM_(2.5) and PM_(10) particulates in Beijing,China

The distribution and source of the solvent-extractable organic and inorganic components in PM _(2.5)(aerodynamics equivalent diameter below 2.5 microns),and PM _(10)(aerodynamics equivalent diameter below 10 microns) fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing.The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes,PAHs(polycyclic aromatic hydrocarbons),fatty acids and water soluble ions.The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index(CPI),%waxC n,selected diagnostic ratios of PAHs and principal component analysis in both size ranges.The mean cumulative concentrations of n-alkanes reached 1128.65ng/m~3 in Beijing,74% of which(i.e.,831.7ng/m~3) was in the PM _(2.5) fraction,PAHs reached 136.45ng/m~3(113.44ng/m~3 or 83% in PM _(2.5)),and fatty acids reached 436.99ng/m~3(324.41ng/m~3 or 74% in PM _(2.5)),which resulted in overall enrichment in the fine particles.The average concentrations of SO_4~(2-),NO_3~-,and NH_4~+ were 21.3±15.2,6.1±1.8,12.5±6.1μg/m~3 in PM _(2.5),and 25.8±15.5,8.9±2.6,16.9±9.5μg/m3 in PM_(10),respectively.These three secondary ions primarily existed as ammonium sulfate((NH_4)_2SO_4),ammonium bisulfate(NH_4HSO_4) and ammonium nitrate(NH_4NO_3).The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion,followed by gasoline combustion.The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles.The major alkane sources were biogenic sources and fossil fuel combustion.The major sources of PAHs were vehicular emission and coal combustion.
Influence of SO_2 in incineration flue gas on the sequestration of CO_2 by municipal solid waste incinerator fly ash

The influence of CO_2 content and presence of SO_2 on the sequestration of CO_2 by municipal solid waste incinerator(MSWI) fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas.The reaction between fly ash and 100% CO_2 was relatively fast;the uptake of CO_2 reached 87g CO_2/kg ash,and the sequestered CO_2 could be entirely released at high temperatures.When CO_2 content was reduced to 12%,the reaction rate decreased;the uptake fell to 41g CO_2/kg ash,and 70.7% of the sequestered CO_2 could be released.With 12% CO_2 in the presence of SO_2,the reaction rate significantly decreased;the uptake was just 17g CO_2/kg ash,and only 52.9% of the sequestered CO_2 could be released.SO_2 in the simulated gas restricted the ability of fly ash to sequester CO_2 because it blocked the pores of the ash.
Observed levels and trends of gaseous SO_2 and HNO_3 at Mt.Waliguan,China:Results from 1997 to 2009

Long-term measurements of SO_2 and HNO_3,particularly those from the background sites,are rarely reported.We present for the first time the long-term measurements of SO_2 and HNO_3 at Waliguan(WLG),the only global baseline station in the back-land of the Eurasian Continent.The concentrations of SO_2 and HNO_3 were observed at WLG from 1997 to 2009.The observed annual mean concentrations of SO_2 and HNO_3 at WLG were 1.28±0.41 and 0.22±0.19μg/m3,respectively.The HNO_3 concentrations were much higher in warmer seasons than in colder seasons,while the SO_2 concentrations showed a nearly reversed seasonal pattern.In most months,the concentration of HNO_3 was significantly correlated with that of SO_2,suggesting that some common factors influence the variations of both gases and the precursors of HNO_3 may partially be from the SO_2-emitting sources.The SO_2 concentration had a very significant(P < 0.0001) decreasing trend(-0.2μg/(m~3·yr)) in 1997-2002,but a significant(P < 0.05) increasing trend(+0.06 μg/(m ~3 ·yr)) in 2003-2009.The HNO_3 concentration showed no statistically significant trend during 1997-2009.While the decrease of SO_2 in 1997-2002 agrees with the trend of global SO_2 emissions,the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world.Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO_2 and HNO_3 at WLG in 2003-2009,with a rate of +0.13μg/(m~3·yr) and +0.007μg/(m~3·yr),respectively.
Flow field and dissolved oxygen distributions in the outer channel of the Orbal oxidation ditch by monitor and CFD simulation

In the Orbal oxidation ditch,denitrification is primarily accomplished in the outer channel.However,the detailed characteristics of the flow field and dissolved oxygen(DO)distribution in the outer channel are not well understood.Therefore,in this study,the flow velocity and DO concentration in the outer channel of an Orbal oxidation ditch system in a wastewater treatment plant in Beijing(China)were monitored under actual operation conditions.The flow field and DO concentration distributions were analyzed by computed fluid dynamic modeling.In situ monitoring and modeling both showed that the flow velocity was heterogeneous in the outer channel.As a result,the DO was also heterogeneously distributed in the outer channel,with concentration gradients occurring along the flow direction as well as in the cross-section.This heterogeneous DO distribution created many anoxic and aerobic zones,which may have facilitated simultaneous nitrification-denitrification in the channel.These findings may provide supporting information for rational optimization of the performance of the Orbal oxidation ditch.
Preparation and characterization of Cd_(1-x)Zn_xS buffer layers for thin film solar cells

Cd_(1-x)Zn_xS(x = 0, 0.1, 0.2, 0.3, 1.0) thin films have been grown successfully on soda-lime glass substrates by chemical bath deposition technique as a very promising buffer layer material for optoelectronic device applications. The composition, structural properties, surface morphology, and optical properties of Cd_(1-x)Zn_xS thin films were characterized by energy dispersive analysis of X-ray technique (EDAX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectrophotometer techniques, respectively. The annealed films were observed to possess the deficient sulfur composition. The results of XRD show that the Cd_(1-x)Zn_xS (x = 0.1) thin film annealed at 450 ℃ forms hexagonal (wurtzite) structure with lattice parameters a = 0.408814 nm, c = 0.666059 nm, and its average grain size is 24.9902 nm. The diffraction peaks become strong with the increasing annealing temperatures. The surface of Cd_(1-x)Zn_xS (x = 0.1) thin film annealed at 450℃ is uninterrupted and homogenous as compared to other temperatures. From optical properties, it is observed that the presence of small amount of Zn results in marked changes in the optical band gap of CdS. The band gaps of the Cd_(1-x)Zn_xS thin films vary from 2.42 to 3.51 eV as composition varies from x = 0.0 to 1.0.
Speciation of organic phosphorus in a sediment profile of Lake Taihu I:Chemical forms and their transformation

Organic phosphorus(nonreactive P,NRP)is a major component of P in sediments,but information about its chemical forms and dynamic transformation is limited.The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu,a freshwater and eutrophic lake in China,were investigated.Five forms of NRP in the sediments were extracted based on a chemical fractionation technique,including easily labile NRP(NaHCO_3-NRP),reactive metal oxide-bound NRP(HCl-NRP),humic acid-associated NRP(NaOH-NRP_(HA)),fulvic acid-associated NRP(NaOH-NRP_(FA))and residual NRP(Res-TP).There were notable transformations with increasing sediment depth from the labile NaHCO_3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools,which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded.Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP.The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.
三棱化学成分与质量评价的研究进展

目的:为三棱的进一步研究提供参考。方法:查阅国内、外相关文献,对三棱的化学成分、药理作用及药材质量评价的研究进展进行综述。结果与结论:三棱主要含挥发油类、有机酸类、黄酮类、苯丙素类、皂苷类、甾醇类、糖类、生物碱类及微量元素等化学成分,其中黄酮类、皂苷类、阿魏酸、p-香豆酸、甘露醇和β-谷甾醇的药理作用与三棱活血化瘀的功效一致;其药材质量评价方法单一,所建体系不完善,应将三棱化学成分的研究与其功效相结合,建立多指标和指纹图谱相结合的药材质量评价体系。
Multidisciplinary Design Optimization of Vehicle Instrument Panel Based on Multi-objective Genetic Algorithm

Typical multidisciplinary design optimization(MDO) has gradually been proposed to balance performances of lightweight, noise, vibration and harshness(NVH) and safety for instrument panel(IP) structure in the automotive development. Nevertheless, plastic constitutive relation of Polypropylene(PP) under different strain rates, has not been taken into consideration in current reliability-based and collaborative IP MDO design. In this paper, based on tensile test under different strain rates, the constitutive relation of Polypropylene material is studied. Impact simulation tests for head and knee bolster are carried out to meet the regulation of FMVSS 201 and FMVSS 208, respectively. NVH analysis is performed to obtain mainly the natural frequencies and corresponding mode shapes, while the crashworthiness analysis is employed to examine the crash behavior of IP structure. With the consideration of lightweight, NVH, head and knee bolster impact performance, design of experiment(DOE), response surface model(RSM), and collaborative optimization(CO) are applied to realize the determined and reliability-based optimizations, respectively. Furthermore, based on multi-objective genetic algorithm(MOGA), the optimal Pareto sets are completed to solve the multi-objective optimization(MOO) problem. The proposed research ensures the smoothness of Pareto set, enhances the ability of engineers to make a comprehensive decision about multi-objectives and choose the optimal design, and improves the quality and efficiency of MDO.
磁性固相萃取吸附剂研究的新进展

海胆状磁性二氧化钛微球的合成及在磷酸化多肽选择性富集中的应用蛋白质的磷酸化修饰与多种生物学过程密切相关,如DNA损伤修复、转录调节、信号传导、细胞凋亡等。磷酸化蛋白质及多肽的研究有助于阐明上述过程的机理,进一步认识生命活动的本质。然而它们的相对低丰度和负电性为研究者带来了不小的困难,因此低丰度的磷酸化蛋白质或多肽的选择性富集一直是极具挑战性的研究课题之一。目前有许多金属氧化物被修饰于磁性材料表面用于选择性吸附磷酸化蛋白质和多肽的研究。其中,二氧化钛(TiO_2)由于其对磷酸化蛋白质和多肽具有较高的选择性和稳定性,且易于制备,因此受到了极大的关注。相比传统的球形TiO_2纳米粒子,棒状TiO_2纳米粒子具有更高的表面积/体积比,能够提供更多的吸附活性位点。许国旺课题组~([1])目前制备了一种海胆状磁性金红石型TiO_2纳米棒,将其应用于磷酸肽的选择性富集或磷酸胆碱类化合物的选择性转移过程中,获得了令人满意的结果。具体的制备方法如下:首先将Fe_3O_4表面包裹一层二氧化硅(SiO_2),然后在反应体系中逐滴滴加钛酸四丁酯(Ti[OBu]_4)溶液,形成二氧化钛低聚物后,对其进行煅烧,使单分散Fe_3O_4@SiO_2表面形成锐钛矿的纳米晶种;将制备的锐钛矿纳米晶种在水热条件下生长为海胆状TiO_2磁性纳米粒子(金红石型)。这种海胆状磁性TiO_2纳米粒子对含磷酸的分子具有很高的选择性,能够选择性地从复杂的样品中富集磷酸肽,或在代谢组学研究中选择性除去血浆中一些磷酸胆碱类化合物,降低了基质效应,提高了低丰度代谢物的检测灵敏度。
Molecular Detection of Phytophthora tentaculatain Infected Aucklandia lappa Tissues andSoil on the Basis of Ypt1 Gene

A species-specific PCR assay was established for rapid and accurate detection of the oomycete pathogen Phytophthora tentaculata in diseased plant tissues and infected soil.A pair of species-specific primers Pt1/Pt2 were designed on the basis of Ras-related protein (Ypt1) gene sequences of the Phytophthora species.PCR amplification with the Pt primers resulted in a 386 bp product only from isolates of P.tentaculata.The detection threshold with Pt primers was 100 pg of genomic DNA.A nested PCR procedure was developed using Ypt1F/Ypt1R as the first-round amplification primers and Pt1/Pt2 as the second-round primers,which increased the detection sensitivity 100-fold to 1 pg.PCR using these Pt primers can also be used to detect P.tentaculata in naturally infected plant tissues and soil.The PCR-based method developed in this study provides a rapid and sensitive tool for detection of P.tentaculata.
胃萎Ⅰ号颗粒治疗慢性萎缩性胃炎脾胃虚弱证患者62例临床观察

目的:评价胃萎Ⅰ号颗粒治疗慢性萎缩性胃炎脾胃虚弱证的临床疗效。方法:采用多中心、随机、双盲双模拟、平行对照的临床研究设计,对6家研究中心101例脾胃虚弱型慢性萎缩性胃炎(CAG)患者,按GCP规范进行了临床试验研究,疗程3个月,观察症状学指标、胃镜下黏膜改变及病理组织学的变化,与维酶素对照,评价胃萎Ⅰ号治疗脾胃虚弱型CAG的临床疗效。结果:胃萎Ⅰ号组(党参15g、炒白术10g、法半夏6g、茯苓12g、陈皮6g、广木香6g、砂仁2g、炙甘草3g、白花蛇舌草15g,1袋/日,冲服,分2次服,3个月为1疗程,共服1疗程)治疗前后主症和次症的改善率均﹥70%,而维酶素组﹥30%、﹤70%,则显示了有效。胃萎Ⅰ号组症状疗效的总有效率为87.10%,维酶素组为56.41%(P﹤0.05)。胃萎Ⅰ号组治疗前后胃镜下萎缩积分减少率及病理分级积分减少率分别为26.58%、35.48%,而维酶素组则分别为22.64%、21.31%(P>0.05)。结论:胃萎Ⅰ号颗粒能有效的改善脾胃虚弱型CAG临床症状,对胃镜下粘膜征象及病理萎缩状态有一定的治疗作用,显示出较对照药的疗效优势强项。
Alternate Furrow Irrigation: A Practical Way to Improve Grape Quality and Water Use Efficiency in Arid Northwest China

Field experiments were conducted for two years to investigate the benefits of alternate furrow irrigation on fruit yield, quality and water use efficiency of grape (Vitis vinifera L. cv. Rizamat) in the arid region of Northwest China. Two irrigation treatments were included, i.e., conventional furrow irrigation (CFI, two root-zones were simultaneously irrigated during the consecutive irrigation) and alternate partial root-zone furrow irrigation (AFI, two root-zones were alternatively irrigated during the consecutive irrigation). Results indicate that AFI maintained similar photosynthetic rate (P_n) but with a reduced transpiration rate when compared to CFI. As a consequence, AFI improved water use efficiency based on evapotranspiration (WUE_(ET), fruit yield over water consumed) and irrigation (WUEI, fruit yield over water irrigated) by 30.0 and 34.5%, respectively in 2005, and by 12.7 and 17.7%, respectively in 2006. AFI also increased the edible percentage of berry by 2.91-4.79% significantly in both years. Vitamin C (V_c) content content of berry was increased by 25.6-37.5%, and tritrated acidity (TA) was reduced by 9.5-18.1% in AFI. This resulted in an increased total soluble solid content (TSS) to TA ratio (TSS/TA) by 11.5-16.7% when compared to CFI in both years. Our results indicate that alternate furrow irrigation is a practical way to improve grape fruit quality and water use efficiency for irrigated crops in arid areas.
Drip Irrigation Scheduling for Tomato Grown in Solar Greenhouse Based on Pan Evaporation in North China Plain

This study has investigated the suitable drip irrigation scheduling for tomato grown in solar greenhouse based on 20-cm pan evaporation (E_(pan)) in North China Plain. Irrigation treatments included three irrigation frequencies (I_1 10, I_2 20 and I_3 30 mm, and irrigation interval of 2-6 d for I_1, 4-9 d for I_2 and 8-12 d for I_3) based on accumulated pan evaporation (E_(pan)), and four plant-pan coefficients (K_(cp1) 0.5, K_(cp2) 0.7, K_(cp3) 0.9 and K_(cp4) 1.1). Results indicate that total irrigation amount, seasonal crop evapotranspiration (ET) and tomato yield (Y) were 185.1-365.8 mm, 249.1-388.0 mm and 99.6-151.8 t ha~(-1), respectively. Irrigation frequency and amount increased the yield, and second-degree polynomial relationship was found between Y and ET (R~2=0.8671). Irrigation frequency did not increase mean fruit weight, diameter and length significantly but increased fruit number, total soluble solids content (TSS), TSS yield, fruit firmness and water use efficiency (WUE) and irrigation WUE (IWUE) significantly. Irrigation amount increased external quality of tomato but reduced TSS content, TSS yield, fruit firmness, WUE and IWUE significantly. K_(cp3) and K_(cp4) treatments had the highest fruit yield, but K_(cp2) and K_(cp3) treatments had the highest WUE. I_1K_(cp3) treatment (irrigation interval of 2-6 d, and K_(cp)=0.9) had higher IWUE, WUE, external quality, yield, and TSS yield, so it is recommended as the suitable irrigation scheduling for tomato grown in solar greenhouse in North China Plain.
Assessing Maize Drought Hazard for Agricultural Areas Based on the Fuzzy Gamma Model

Drought is one of the severe meteorological disasters and causes of serious losses for agricultural productions, and early assessment of drought hazard degree is critical in management of maize farming. This study proposes a novel method for assessment of maize drought hazard in different growth stages. First, the study divided the maize growth period into four critical growth stages, including seeding, elongation, tasseling, and filling. Second, maize drought causal factors were selected and the fuzzy membership function was established. Finally, the study built a fuzzy gamma model to assess maize drought hazards, and the gamma 0.93 was finally established using Monte Carlo Analysis. Performing fuzzy gamma operation with 0.93 for gamma and classifying the area yielded a map of maize drought hazards with four zones of light, moderate, severe, and extreme droughts. Using actual field collected data, seven selected samples for drought hazard degree were examined, the model output proved to be a valid tool in the assessment maize drought hazard. This model will be very useful in analyzing the spatial change of maize drought hazard and influence on yield, which is significant for drought management in major agricultural areas.
Development of SRAP Markers Linked to a Gene for Stem Nematode Resistance in Sweetpotato, Ipomoea batatas (L.) Lam

Sequence-related amplification polymorphism (SRAP) markers closely linked to stem nematode resistance gene were developed in sweetpotato, Ipomoea batatas (L.) Lam. Using bulked segregant analysis (BSA), 200 SRAP primer combinations were screened with the resistant and susceptible bulked DNA from the 196 progenies of an F_1 single-cross population of resistant parent Xu 781×susceptible parent Xushu 18, 77 of them showed polymorphic bands between resistant and susceptible DNA. Primer combinations detecting polymorphism between the two bulks were used to screen both parents and 10 individuals from each of the bulks. The results showed that primer combination A_9B_4 produced 3 specific bands in the resistant plants but not in the susceptible plants, suggesting that the markers, named Nsp1, Nsp2 and Nsp3, respectively, linked to a gene for stem nematode resistance. Primer combination A_3B_6 also produced a SRAP marker named Nsp4 linking to the resistance gene. Amplified analysis of the 196 F_1 individuals indicated that the genetic distance between these markers and the resistance gene was 4.7, 4.7, 6.3, and 9.6 cM, respectively.
Comparative Proteomic Analysis of Spike-Development Inhibited and Normal Tillers of Wheat 3558

Spike number is one of three yield-related factors and is closely related to wheat yield. In the present study, we found that the inhibited and normal tillers of the 3558 line presented phenotypic differences at the elongation stage by morphological and anatomical analysis. We then initiated a proteomic study using two-dimensional electrophoresis (2-DE) and nanoscale liquid chromatography-high-definition tandem mass spectroscopy, to isolate and identify the key proteins and metabolic pathways related to spike-development inhibition. A total of 31 differentially expressed proteins (DEPs), which were mainly involved in cell cycle regulation, photosynthesis, glycolysis, stress response, and oxidation-reduction reactions, were isolated and identified. 14-3-3-like proteins and proliferating cell nuclear antigen (PCNA), involved in cell-cycle regulation, were dramatically down-regulated in inhibited tillers compared to normal tillers. Six spots corresponding to degraded Rubisco large subunits, involved in photosynthesis, were detected in different locations of the 2-DE gels and were up-regulated in inhibited tillers. In addition, the relative levels of DEPs involved in glycolysis and oxidationreduction reactions changed dramatically. Development was blocked or delayed at the elongation stage in the inhibited tillers of 3558. Weakened energy metabolism might be one reason that the inhibited tillers could not joint and develop into spikes. These DEPs and related metabolic pathways are significant for understanding the mechanism of spike-development inhibition and studying the spike-development process in wheat.
Preparation, characterization, and antibacterial activity of γ-irradiated silver nanoparticles in aqueous gelatin

Colloidal silver nanoparticles (Ag-NPs) were obtained through γ-irradiation of aqueous solutions containing AgNO_3 and gelatin as a silver source and stabilizer, respectively. The absorbed dose of γ-irradiation influences the particle diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) and transmission electron microscopy (TEM) images. When the γ-irradiation dose was increased (from 2 to 50 kGy), the mean particle size was decreased continuously as a result of γ-induced Ag-NPs fragmentation. The antibacterial properties of the Ag-NPs were tested against Methicillinresistant Staphylococcus aureus (MRSA) (Gram-positive) and Pseudomonas aeruginosa (P.a) (Gram-negative) bacteria. This approach reveals that the γ-irradiation-mediated method is a promising simple route for synthesizing highly stable Ag-NPs in aqueous solutions with good antibacterial properties for different applications.
Effects of the shape and size of rectangular inclusions on the fatigue cracking behavior of ultra-high strength steels

The fatigue cracking behavior of ultra-high strength steels containing rectangular inclusions of small sizes were investigated based on in situ observations by scanning electron microscopy (SEM). The size and shape of rectangular inclusions affect markedly the initiation site and propagation path of a fatigue crack. Especially, the initiation site of a fatigue crack depends strongly on the angle between the long-axis of a rectangle inclusion and the loading direction, and the length/width ratio of this rectangle inclusion because the residual stress distribution fields vary with these conditions. The results coincide very well with those of finite element analysis.
A LIM Domain Protein from Tobacco Involved in Actin-Bundling and Histone Gene Transcription

The two LIM domain-containing proteins from plants (LIMs) typically exhibit a dual cytoplasmic-nuclear distribution, suggesting that, in addition to their previously described roles in actin cytoskeleton organization, they participate in nuclear processes. Using a south-western blot-based screen aimed at identifying factors that bind to plant histone gene promoters, we isolated a positive clone containing the tobacco LIM protein WLIM2 (NtWLIM2) cDNA. Using both green fluorescent protein (GFP) fusion-and immunology-based strategies, we provide clear evidence that NtWLIM2 localizes to the actin cytoskeleton, the nucleus, and the nucleolus. Interestingly, the disruption of the actin cytoskeleton by latrunculin B significantly increases NtWLIM2 nuclear fraction, pinpointing a possible novel cytoskeletal-nuclear crosstalk. Biochemical and electron microscopy experiments reveal the ability of NtWLIM2 to directly bind to actin filaments and to crosslink the latter into thick actin bundles. Electrophoretic mobility shift assays show that NtWLIM2 specifically binds to the conserved octameric cis-elements (Oct) of the Arabidopsis histone H4A748 gene promoter and that this binding largely relies on both LIM domains. Importantly, reporter-based experiments conducted in Arabidopsis and tobacco protoplasts confirm the ability of NtWLIM2 to bind to and activate the H4A748 gene promoter in live cells. Expression studies indicate the constitutive presence of NtWLIM2 mRNA and NtWLIM2 protein during tobacco BY-2 cell proliferation and cell cycle progression, suggesting a role of NtWLIM2 in the activation of basal histone gene expression. Interestingly, both live cell and in vitro data support NtWLIM2 di/oligomerization. We propose that NtWLIM2 functions as an actin-stabilizing protein, which, upon cytoskeleton remodeling, shuttles to the nucleus in order to modify gene expression.