The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity...The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.展开更多
Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CA...Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.展开更多
Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics.In this study,three low-cost small molecules of spiro-linked hole transporting ...Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics.In this study,three low-cost small molecules of spiro-linked hole transporting materials(SFX-O-2 F,SFX-m-2 F,and SFX-p-2 F) endowed with two-armed t rip he ny la mine moieties were synthesized via tuning of the fluorine substitution position,and they were employed for use in highly efficient perovskite solar cells(PSCs).Despite the fluorine substitution position playing a negligible role in the optical and electrochemical properties of the resulting small molecules,the photovoltaic performance thereof was observed to vary significantly.The planar n-i-p PSCs based on SFX-m-2 F demonstrated superior performance(18.86%) when compared to that of the corresponding SFX-o-2 F(9.7%) and SFX-p-2 F(16.33%) under 100 mW cm^(-2) AM1.5 G solar illumination,which is competitive with the performance of the benchmark spiro-OMeTAD-based device(18.98%).Moreover,the SFX-m-2 Fbased PSCs were observed to be more stable than the spiro-OMeTAD-based devices under ambient conditions.The improved performance of SFX-m-2 F is primarily associated with improved morphology,more efficient hole transport,and extraction characteristics at the perovskite/HTM interface.This work demonstrated the application of fluorination engineering to the tuning of material film morphology and charge transfer properties,showing the promising potential of fluorinated SM-HTMs for the construction of low-cost,high-efficiency PSCs.展开更多
Grain size and shape are important factors for yield and quality.The difference in grain phenotypic characteristics in the same maize hybrid is related to its position in the ear.This study aimed to clarify the distri...Grain size and shape are important factors for yield and quality.The difference in grain phenotypic characteristics in the same maize hybrid is related to its position in the ear.This study aimed to clarify the distribution characteristics of grain morphological characteristics in the ear and to provide guidance for research of grain phenotype and kernel position effects.Three maize hybrids were used in the experiment,namely,Denghai 618(DH618),KX3564,and Xianyu 335(XY335),and the kernel number per row were 40,40,and 36,respectively.The X-rayμCT was applied to obtain five kernel morphological indicators,including grain length,width,thickness,volume,surface area.Grain sphericity,length-width ratio,specific surface area,and volume coefficient were further calculated.The results showed that there were three types of maize ear morphological indicators trends:grain length,width,volume,and surface area were parabolic;thickness and sphericity were inverted parabolic;length-to-width ratio and specific surface area were irregular.The volume coefficient of grain at different parts of the ear,namely the relation coefficient between grain volume and grain length,width,and thickness,was determined.The average value of the middle grains morphological indicators of the ear was taken to select kernels representing stable characteristics of the variety.Within the range of 5%deviation from the morphological mean value of the middle grains of the ear,the grains in the middle part accounted for 26.39%of the total ear,about 10 grains extending from the 14th grain at the base of the ear to the top.Within the range of 10%deviation,the middle accounted for 47.22%,about 18 grains extending from the 12th grain at the base of the ear to the top.This study found that grain morphological indicators were greatly different at different positions of the maize ear,and showed different change rules as extend from the base to the top of the ear.Therefore,there were different grain volume coefficients at different positions of maize ear.And the representative sampling range on maize ear was determined based on the comprehensive analysis of different morphological indexes variation of grain.展开更多
The position effect of the photoelectron multiplier tube （PMT） of the electromagnetic calorimeter （ECAL） of Alpha Magnetic Spectrometer-02 （AMS-02） has been studied with beam-test data. The reconstructed deposit...The position effect of the photoelectron multiplier tube （PMT） of the electromagnetic calorimeter （ECAL） of Alpha Magnetic Spectrometer-02 （AMS-02） has been studied with beam-test data. The reconstructed deposited energy in a layer versus incidence position in the cell can be described by Gaussian distribution, maximum and minimum value can be obtained when the particle passes across the center and the edge of a cell respectively. The distribution can be used to correct the effect of incidence position on energy reconstruction. Much better energy resolution was acquired be got with the correction, for 100 GeV electrons, energy resolution improved from 3% to 2%.展开更多
The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bact...The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bacterium Myxococcus xanthus harbors a large circular high-GC genome,and the position effect in this chassis may result in a thousand-fold expression variation of alien natural products.In this study,we conducted transposon insertion at TA sites on the M.xanthus genome,and used enrichment and dilution indexes to respectively appraise high and low expression potentials of alien genes at insertion sites.The enrichment sites are characteristically distributed along the genome,and the dilution sites are overlapped well with the horizontal transfer genes.We experimentally demonstrated the enrichment sites as high expression integration sites(HEISs),and the dilution sites unsuitable for gene integration expression.This work highlights that HEISs are the plug-and-play sites for efficient expression of integrated genes.展开更多
AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation...AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P 】0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P 【0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.展开更多
Structure-efficacy effect of small molecular drug attracts wide attentions,but it has always been ignored in nanomedicine research.To reveal the efficacy modulation of nanomedicine,we developed a new type of paclitaxe...Structure-efficacy effect of small molecular drug attracts wide attentions,but it has always been ignored in nanomedicine research.To reveal the efficacy modulation of nanomedicine,we developed a new type of paclitaxel(PTX)-conjugated gold nanoparticles(PTX-co njugated GNPs)to investigate the influence of drug position in controlling their in vitro properties and in vivo performance.Two therapeutic ligands(TA-PEG-NH-N=PTX and TA-PTX=N-NH-PEG)were synthesized to conjugate PTX on the surface of GNPs at different positions,locating on the surface of gold conjugate and inserting between GNPs and polyethylene glycol(PEG,molecular weight 1000 Da),respectively.It was found that PEG-PTX@GNPs with PTX located between GNP and PEG exhibited higher aqueous solubility,biocompatibility,and stability.In addition,an acid sensitive hydrazone bond has been inserted between PTX and PEG in both ligands for drug release of PTX and PTX-PEG segment,respectively,at the tumor site.Further release of PTX from PTX-PEG segment is based on the esterase hydrolysis of an ester bond between PTX and PEG.This two-step drug release mechanism offers PEG-PTX@GNPs effective and sustained release behavior for desirable anticancer activity,enhanced therapeutic efficacy,and lower systematic toxicity in Hepsbearing animal models.展开更多
Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning i...Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning is presented herein.Data used for this study refer to the winter and summer periods of the years with minimal(2008)and maximal(2013)solar activity.These data were collected every 30 s in static mode,at two permanent GPS stations located in Montenegro,establishing a mediumdistance(116-km-long)baseline with a height difference of approximately 760 m between its endpoints.The study showed that changing satellite elevation cutoff angle,with a fixed PDOP mask,affects epochwise two-way nested ANOVA estimates of variances related to the‘far-field’multipath(considered as the nested factor herein)and the combined unmodeled effect of tropospheric and ionospheric refraction(considered as the nesting factor herein).However,changing of PDOP mask,with a fixed satellite elevation cutoff angle,doesn’t affect epoch-wise two-way nested ANOVA estimate of variance of the combined unmodeled effect of tropospheric and ionospheric refraction,but,generally,affects the estimate of variance of the‘far-field’multipath(possibly mixed with a part of a‘shorter-term’ionospheric refraction),which is especially pronounced for the summer period.It should also be noted that there is a significant influence of satellite elevation cutoff angle change on both epoch-wise horizontal and vertical position accuracy,only for the summer period,especially in the presence of maximal solar activity,while there is no significant impact of PDOP mask change on epoch-wise positional accuracy.展开更多
The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were stu...The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.展开更多
We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion...We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.展开更多
Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent （CHA111）, aminated hypercrosslinked polymeric...Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent （CHA111）, aminated hypercrosslinked polymeric adsorbents （NDA101, NDA103, NDA105） and weakly basic polymeric adsorbent （D301） with a view to studying the effect of hydrogen bonding and Van der Waals interactions between adsorbate and the adsorbent. All adsorption isotherms can be well fitted by Langmuir and Freundlich equations. Compared with D301 driven by hydrogen bonding interaction only and CHA111 driven by Van der Waals interaction only, phenol adsorption on aminated adsorbents driven by both hydrogen bonding and Van der Waals interactions were apparently different, i.e., negative effect for NDA105, positive effect for NDA101 and synergistic effect for NDA103. In this synergistic action, some weak interactions would contribute more or less to the adsorption than they work individually.展开更多
With the development of computer and network technologies, computer--assisted language teaching and learning have been changing from the presentation of single text materials and response model to the integration of o...With the development of computer and network technologies, computer--assisted language teaching and learning have been changing from the presentation of single text materials and response model to the integration of outside classroom education media combining text, graphics, images, sound, animation and network communication （CMC） technology. As an auxiliary tool of foreign language teaching, the computer plays its huge potential and promotes the completion of all kinds of language learning tasks. However, high cost and lack of technical support bringing the negative effects to the foreign language teaching is also cannot be ignored. Therefore, in the study of the historical evolvement of the CALL, to fully understand the positive and negative effects from the foreign language teaching will help make the positive effect of foreign language teaching maximized, and avoid misuse and abuse of the CALL.展开更多
AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 group...AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 groups:Group A(implanted with the SN6CWS),Group B(implanted with the MI60),and Group C(implanted with the Aspira-aA).ELP measurements were obtained with swept-source optical coherence tomography(SS-OCT)at 1d,1wk,1mo,and 3mo postoperatively.Subjective refraction assessments were conducted at 1wk,1mo,and 3mo following surgery.RESULTS:The study included 189 eyes of 150 cataract patients(66 males).There were 77 eyes in Group A,55 eyes in Group B,and 57 eyes in Group C.The root mean square of the ELP(ELPRMS)within the initial 3mo was significantly lower for Group A than for Groups B and C.Refractive changes within Group A were not significant across the time points of 1wk,1mo,and 3mo.Conversely,both Group B and Group C demonstrated statistically significant shifts toward hyperopia from 1wk to 3mo postsurgery.CONCLUSION:Among the three IOLs examined,the SN6CWS IOL showes the greatest stability during the first 3mo postoperatively.Between 1wk and 3mo after surgery,notable hyperopic shifts are evident in eyes implanted with the MI60 and Aspira-aA IOLs,whereas refractive outcomes remain relatively constant in eyes implanted with SN6CWS IOLs.展开更多
Under an environment full of competitive stress,students tend to form negative emotions,and the time for them to engage in physical exercise is greatly limited due to overwhelming academic tasks.Therefore,in this pape...Under an environment full of competitive stress,students tend to form negative emotions,and the time for them to engage in physical exercise is greatly limited due to overwhelming academic tasks.Therefore,in this paper,we focus on acknowledging the purpose of physical exercise,and how physical exercise affects the mental health of students under stressful circumstances but not in the context of leisure.Questionnaire was distributed to participants with an average age of 20,to investigate their preference,frequency,and reason for exercising,and their attitude towards it.Our results showed that participants think that exercise can strengthen the body,relieve stress,improve fitness and interpersonal relationship regardless of their purpose such as interests,emotional necessity and even out of non-subjective ideas.In conclusion,physical exercise helped to improve students’mental health especially under great pressure and ultimately,it will enhance their academics and bring about the unity of mind and body.展开更多
This article explores the potential ways to enhance effective EFL teaching in EFL classroom. The author considered that elements such as teacher＇s understandings of classroom structures, the differences in classroom ...This article explores the potential ways to enhance effective EFL teaching in EFL classroom. The author considered that elements such as teacher＇s understandings of classroom structures, the differences in classroom norms and creation of positive climate could contribute to the overall EFL classroom effectiveness. By referencing contemporary EFL teaching theories, the author attempted to touch on the implications to the contemporary Chinese EFL education. It has suggested that teachers should gain thorough understanding of those elements in their daily practice.展开更多
抓挠“痒痒包”到底是好是坏?这个看似简单的动作背后竟有科学奥秘!Don’t scratch that mosquito(蚊子)bite!Maybe you’ve heard this advice before-and found it hard to follow.So you may already know that scratching can feel ...抓挠“痒痒包”到底是好是坏?这个看似简单的动作背后竟有科学奥秘!Don’t scratch that mosquito(蚊子)bite!Maybe you’ve heard this advice before-and found it hard to follow.So you may already know that scratching can feel good at the time,but may not help in the long run.A study in mice finds that scratching can have both positive and negative effects.展开更多
Two-dimensional(2D)materials with tunable electronic transitions are vital for next-generation electronics and energy storage technologies.Here,we demonstrate a novel,thermally-driven,reversible modulation of electron...Two-dimensional(2D)materials with tunable electronic transitions are vital for next-generation electronics and energy storage technologies.Here,we demonstrate a novel,thermally-driven,reversible modulation of electronic conductivity in the quaternary heteroanionic 2D van der Waals superlattice Bi_(4)O_(4)SeCl_(2).Systematic thermal annealing of bulk Bi_(4)O_(4)SeCl_(2)induces a striking reversible transition from insulating to semiconducting behavior,accompanied by a 10~6 times magnitude enhancement in electrical conductivity.This dramatic transformation originates from thermally mediated defect annihilation and grain boundary elimination,substantially reducing carrier scattering barriers and enhancing intrinsic carrier concentration.Moreover,leveraging its intrinsic layered structure,we successfully exfoliated Bi_(4)O_(4)SeCl_(2)into nanosheets(~1.5 nm in thickness)and utilized these exfoliated layers as interfacial coatings on Zn electrodes,markedly improving dendrite suppression and extending the cycling stability of Zn-ion hybrid capacitors and Zn/MnO_(2)batteries.Our work elucidates crucial defect-driven micro s tructural mechanisms responsible for thermally-induced reversible electronic transitions,establishing heteroanionic Bi_(4)O_(4)SeCl_(2)as a promising platform for advanced electronic and energystorage materials engineering.展开更多
Positive associations between alpine cushion plants and other species have been extensively studied.However,almost all studies have focused on the associations between macrofauna.Studies that have investigated positiv...Positive associations between alpine cushion plants and other species have been extensively studied.However,almost all studies have focused on the associations between macrofauna.Studies that have investigated positive associations between alpine cushion plants and rhizospheric microbes have been limited to the vegetation growing season.Here,we asked whether the positive effects that alpine cushion plants confer on rhizospheric microbe communities vary with seasons.We assessed seasonal variations in the bacterial diversity and composition in rhizosphere of two alpine cushion plants and surrounding bare ground by employing a high throughput sequencing method targeting the V3 region of bacterial 16 S rRNA genes.Soil properties of the rhizosphere and the bare ground were also examined.We found that cushion rhizospheres harbored significantly more C,N,S,ammonia nitrogen,and soil moisture than the bare ground.Soil properties in cushion rhizospheres were not notably different,except for soil pH.Bacterial diversities within the same microhabitats did not vary significantly with seasons.We concluded that alpine cushion plants had positive effects on the rhizospheric bacterial communities,even though the strength of the effect varied in different cushion species.Cushion species and the soil sulfur content were probably the major factors driving the spatial distribution and structure of soil bacterial communities in the alpine communities dominated by cushion plants.展开更多
基金fnancially supported by the Natural Science Foundation of Hebei Province,China(C2021301004)the State Key Laboratory of North China Crop Improvement and Regulation,China(NCCIR2023KF-10)the HAAFS Science and Technology Innovation Special Project,China(2022KJCXZX-LYS-9)。
文摘The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.
基金financially supported by the HAAFS Science and Technology Innovation Special Project China(2022KJCXZX-LYS-9)the Natural Science Foundation of Hebei Province China(C2021301004)the Key Research and Dvelopment Program of Hebei Province China(20326401D)。
文摘Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.
基金financially supported by the China Scholarship Council(CSC) project(201808320023)the National Basic Research Program of China-Fundamental Studies of Perovskite Solar Cells(2015CB932200)+2 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Program for Changjiang Scholars and Innovative Research Team in University(IRT-15R37)NJUPT Culturing Project(NY218056 and NY219061)。
文摘Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics.In this study,three low-cost small molecules of spiro-linked hole transporting materials(SFX-O-2 F,SFX-m-2 F,and SFX-p-2 F) endowed with two-armed t rip he ny la mine moieties were synthesized via tuning of the fluorine substitution position,and they were employed for use in highly efficient perovskite solar cells(PSCs).Despite the fluorine substitution position playing a negligible role in the optical and electrochemical properties of the resulting small molecules,the photovoltaic performance thereof was observed to vary significantly.The planar n-i-p PSCs based on SFX-m-2 F demonstrated superior performance(18.86%) when compared to that of the corresponding SFX-o-2 F(9.7%) and SFX-p-2 F(16.33%) under 100 mW cm^(-2) AM1.5 G solar illumination,which is competitive with the performance of the benchmark spiro-OMeTAD-based device(18.98%).Moreover,the SFX-m-2 Fbased PSCs were observed to be more stable than the spiro-OMeTAD-based devices under ambient conditions.The improved performance of SFX-m-2 F is primarily associated with improved morphology,more efficient hole transport,and extraction characteristics at the perovskite/HTM interface.This work demonstrated the application of fluorination engineering to the tuning of material film morphology and charge transfer properties,showing the promising potential of fluorinated SM-HTMs for the construction of low-cost,high-efficiency PSCs.
基金The authors acknowledge that this work was financially supported by the National Key Research and Development Program of China(Grant No.2018YFD0300405)the National Natural Science Foundation of China(Grant No.31971849)+1 种基金earmarked Fund for Modern Agro-industry Technology Research System(CARS-02-25)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences for their financial support.
文摘Grain size and shape are important factors for yield and quality.The difference in grain phenotypic characteristics in the same maize hybrid is related to its position in the ear.This study aimed to clarify the distribution characteristics of grain morphological characteristics in the ear and to provide guidance for research of grain phenotype and kernel position effects.Three maize hybrids were used in the experiment,namely,Denghai 618(DH618),KX3564,and Xianyu 335(XY335),and the kernel number per row were 40,40,and 36,respectively.The X-rayμCT was applied to obtain five kernel morphological indicators,including grain length,width,thickness,volume,surface area.Grain sphericity,length-width ratio,specific surface area,and volume coefficient were further calculated.The results showed that there were three types of maize ear morphological indicators trends:grain length,width,volume,and surface area were parabolic;thickness and sphericity were inverted parabolic;length-to-width ratio and specific surface area were irregular.The volume coefficient of grain at different parts of the ear,namely the relation coefficient between grain volume and grain length,width,and thickness,was determined.The average value of the middle grains morphological indicators of the ear was taken to select kernels representing stable characteristics of the variety.Within the range of 5%deviation from the morphological mean value of the middle grains of the ear,the grains in the middle part accounted for 26.39%of the total ear,about 10 grains extending from the 14th grain at the base of the ear to the top.Within the range of 10%deviation,the middle accounted for 47.22%,about 18 grains extending from the 12th grain at the base of the ear to the top.This study found that grain morphological indicators were greatly different at different positions of the maize ear,and showed different change rules as extend from the base to the top of the ear.Therefore,there were different grain volume coefficients at different positions of maize ear.And the representative sampling range on maize ear was determined based on the comprehensive analysis of different morphological indexes variation of grain.
基金Supported by National Natural Science Foundation of China (10805050)
文摘The position effect of the photoelectron multiplier tube （PMT） of the electromagnetic calorimeter （ECAL） of Alpha Magnetic Spectrometer-02 （AMS-02） has been studied with beam-test data. The reconstructed deposited energy in a layer versus incidence position in the cell can be described by Gaussian distribution, maximum and minimum value can be obtained when the particle passes across the center and the edge of a cell respectively. The distribution can be used to correct the effect of incidence position on energy reconstruction. Much better energy resolution was acquired be got with the correction, for 100 GeV electrons, energy resolution improved from 3% to 2%.
基金the National Key Research and Development Program of China(2021YFC2101000)the National Natural Science Foundation of China(32301220).
文摘The chromosomal position effect can significantly affect the transgene expression,which may provide an efficient strategy for the inauguration of alien genes in new hosts,but has been less explored rationally.The bacterium Myxococcus xanthus harbors a large circular high-GC genome,and the position effect in this chassis may result in a thousand-fold expression variation of alien natural products.In this study,we conducted transposon insertion at TA sites on the M.xanthus genome,and used enrichment and dilution indexes to respectively appraise high and low expression potentials of alien genes at insertion sites.The enrichment sites are characteristically distributed along the genome,and the dilution sites are overlapped well with the horizontal transfer genes.We experimentally demonstrated the enrichment sites as high expression integration sites(HEISs),and the dilution sites unsuitable for gene integration expression.This work highlights that HEISs are the plug-and-play sites for efficient expression of integrated genes.
文摘AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P 】0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P 【0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.
基金supported by grants from the National Natural Science Foundation of China(Nos.31870946,31470916,31500769 and 21705165)the Funding of Double First-rate Discipline Construction of China(No.CPU2018GF07)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities(Nos.2015PT036,2016PT014,and 3011900159)。
文摘Structure-efficacy effect of small molecular drug attracts wide attentions,but it has always been ignored in nanomedicine research.To reveal the efficacy modulation of nanomedicine,we developed a new type of paclitaxel(PTX)-conjugated gold nanoparticles(PTX-co njugated GNPs)to investigate the influence of drug position in controlling their in vitro properties and in vivo performance.Two therapeutic ligands(TA-PEG-NH-N=PTX and TA-PTX=N-NH-PEG)were synthesized to conjugate PTX on the surface of GNPs at different positions,locating on the surface of gold conjugate and inserting between GNPs and polyethylene glycol(PEG,molecular weight 1000 Da),respectively.It was found that PEG-PTX@GNPs with PTX located between GNP and PEG exhibited higher aqueous solubility,biocompatibility,and stability.In addition,an acid sensitive hydrazone bond has been inserted between PTX and PEG in both ligands for drug release of PTX and PTX-PEG segment,respectively,at the tumor site.Further release of PTX from PTX-PEG segment is based on the esterase hydrolysis of an ester bond between PTX and PEG.This two-step drug release mechanism offers PEG-PTX@GNPs effective and sustained release behavior for desirable anticancer activity,enhanced therapeutic efficacy,and lower systematic toxicity in Hepsbearing animal models.
文摘Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning is presented herein.Data used for this study refer to the winter and summer periods of the years with minimal(2008)and maximal(2013)solar activity.These data were collected every 30 s in static mode,at two permanent GPS stations located in Montenegro,establishing a mediumdistance(116-km-long)baseline with a height difference of approximately 760 m between its endpoints.The study showed that changing satellite elevation cutoff angle,with a fixed PDOP mask,affects epochwise two-way nested ANOVA estimates of variances related to the‘far-field’multipath(considered as the nested factor herein)and the combined unmodeled effect of tropospheric and ionospheric refraction(considered as the nesting factor herein).However,changing of PDOP mask,with a fixed satellite elevation cutoff angle,doesn’t affect epoch-wise two-way nested ANOVA estimate of variance of the combined unmodeled effect of tropospheric and ionospheric refraction,but,generally,affects the estimate of variance of the‘far-field’multipath(possibly mixed with a part of a‘shorter-term’ionospheric refraction),which is especially pronounced for the summer period.It should also be noted that there is a significant influence of satellite elevation cutoff angle change on both epoch-wise horizontal and vertical position accuracy,only for the summer period,especially in the presence of maximal solar activity,while there is no significant impact of PDOP mask change on epoch-wise positional accuracy.
基金The work was supported by the National Natural Sci-ence Foundation of China(Nos.41706126,41876173 and 41606176).
文摘The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60978013)the Shanghai Rising Star Project,China (Grant No. 11QA1407400)
文摘We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.
基金This study was funded by the National Natural Science Foundation of China(No.20274017)the Natural Science Foundation of Jiangsu Province(No.BK2004415).
文摘Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent （CHA111）, aminated hypercrosslinked polymeric adsorbents （NDA101, NDA103, NDA105） and weakly basic polymeric adsorbent （D301） with a view to studying the effect of hydrogen bonding and Van der Waals interactions between adsorbate and the adsorbent. All adsorption isotherms can be well fitted by Langmuir and Freundlich equations. Compared with D301 driven by hydrogen bonding interaction only and CHA111 driven by Van der Waals interaction only, phenol adsorption on aminated adsorbents driven by both hydrogen bonding and Van der Waals interactions were apparently different, i.e., negative effect for NDA105, positive effect for NDA101 and synergistic effect for NDA103. In this synergistic action, some weak interactions would contribute more or less to the adsorption than they work individually.
文摘With the development of computer and network technologies, computer--assisted language teaching and learning have been changing from the presentation of single text materials and response model to the integration of outside classroom education media combining text, graphics, images, sound, animation and network communication （CMC） technology. As an auxiliary tool of foreign language teaching, the computer plays its huge potential and promotes the completion of all kinds of language learning tasks. However, high cost and lack of technical support bringing the negative effects to the foreign language teaching is also cannot be ignored. Therefore, in the study of the historical evolvement of the CALL, to fully understand the positive and negative effects from the foreign language teaching will help make the positive effect of foreign language teaching maximized, and avoid misuse and abuse of the CALL.
基金Supported by the Zhejiang Medical Health Science and Technology Project(No.2021KY217)the Basic Public Welfare Research Project of Wenzhou Municipal Science and Technology Bureau(No.2024Y1221).
文摘AIM:To evaluate and compare alterations in the effective lens position(ELP)and refractive outcomes among three distinct intraocular lens(IOL)types.METHODS:Patients with cataracts were enrolled and allocated to 3 groups:Group A(implanted with the SN6CWS),Group B(implanted with the MI60),and Group C(implanted with the Aspira-aA).ELP measurements were obtained with swept-source optical coherence tomography(SS-OCT)at 1d,1wk,1mo,and 3mo postoperatively.Subjective refraction assessments were conducted at 1wk,1mo,and 3mo following surgery.RESULTS:The study included 189 eyes of 150 cataract patients(66 males).There were 77 eyes in Group A,55 eyes in Group B,and 57 eyes in Group C.The root mean square of the ELP(ELPRMS)within the initial 3mo was significantly lower for Group A than for Groups B and C.Refractive changes within Group A were not significant across the time points of 1wk,1mo,and 3mo.Conversely,both Group B and Group C demonstrated statistically significant shifts toward hyperopia from 1wk to 3mo postsurgery.CONCLUSION:Among the three IOLs examined,the SN6CWS IOL showes the greatest stability during the first 3mo postoperatively.Between 1wk and 3mo after surgery,notable hyperopic shifts are evident in eyes implanted with the MI60 and Aspira-aA IOLs,whereas refractive outcomes remain relatively constant in eyes implanted with SN6CWS IOLs.
文摘Under an environment full of competitive stress,students tend to form negative emotions,and the time for them to engage in physical exercise is greatly limited due to overwhelming academic tasks.Therefore,in this paper,we focus on acknowledging the purpose of physical exercise,and how physical exercise affects the mental health of students under stressful circumstances but not in the context of leisure.Questionnaire was distributed to participants with an average age of 20,to investigate their preference,frequency,and reason for exercising,and their attitude towards it.Our results showed that participants think that exercise can strengthen the body,relieve stress,improve fitness and interpersonal relationship regardless of their purpose such as interests,emotional necessity and even out of non-subjective ideas.In conclusion,physical exercise helped to improve students’mental health especially under great pressure and ultimately,it will enhance their academics and bring about the unity of mind and body.
文摘This article explores the potential ways to enhance effective EFL teaching in EFL classroom. The author considered that elements such as teacher＇s understandings of classroom structures, the differences in classroom norms and creation of positive climate could contribute to the overall EFL classroom effectiveness. By referencing contemporary EFL teaching theories, the author attempted to touch on the implications to the contemporary Chinese EFL education. It has suggested that teachers should gain thorough understanding of those elements in their daily practice.
文摘抓挠“痒痒包”到底是好是坏?这个看似简单的动作背后竟有科学奥秘!Don’t scratch that mosquito(蚊子)bite!Maybe you’ve heard this advice before-and found it hard to follow.So you may already know that scratching can feel good at the time,but may not help in the long run.A study in mice finds that scratching can have both positive and negative effects.
基金supported by the National Key Research and Development Program of China(No.2021YFA1200903)National Natural Science Foundation of China(Nos.22175203,22006023,and 11974435)+1 种基金Natural Science Foundation of Guangdong Province(Nos.2022B1515020065 and 2020A1515110821,2023A1515010841,2025A1515010050)Guangzhou Science and Technology Project(No.202102020126)
文摘Two-dimensional(2D)materials with tunable electronic transitions are vital for next-generation electronics and energy storage technologies.Here,we demonstrate a novel,thermally-driven,reversible modulation of electronic conductivity in the quaternary heteroanionic 2D van der Waals superlattice Bi_(4)O_(4)SeCl_(2).Systematic thermal annealing of bulk Bi_(4)O_(4)SeCl_(2)induces a striking reversible transition from insulating to semiconducting behavior,accompanied by a 10~6 times magnitude enhancement in electrical conductivity.This dramatic transformation originates from thermally mediated defect annihilation and grain boundary elimination,substantially reducing carrier scattering barriers and enhancing intrinsic carrier concentration.Moreover,leveraging its intrinsic layered structure,we successfully exfoliated Bi_(4)O_(4)SeCl_(2)into nanosheets(~1.5 nm in thickness)and utilized these exfoliated layers as interfacial coatings on Zn electrodes,markedly improving dendrite suppression and extending the cycling stability of Zn-ion hybrid capacitors and Zn/MnO_(2)batteries.Our work elucidates crucial defect-driven micro s tructural mechanisms responsible for thermally-induced reversible electronic transitions,establishing heteroanionic Bi_(4)O_(4)SeCl_(2)as a promising platform for advanced electronic and energystorage materials engineering.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFC0505200,to Hang Sun)the Major Program of National Natural Science Foundation of China(Grant No.31590823,to Hang Sun)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA20050203,to Hang Sun)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB15020302,to Jianqiang Su)the Yunnan Applied Basic Research Project(Grant No.2018FA015,to Yang Yang)
文摘Positive associations between alpine cushion plants and other species have been extensively studied.However,almost all studies have focused on the associations between macrofauna.Studies that have investigated positive associations between alpine cushion plants and rhizospheric microbes have been limited to the vegetation growing season.Here,we asked whether the positive effects that alpine cushion plants confer on rhizospheric microbe communities vary with seasons.We assessed seasonal variations in the bacterial diversity and composition in rhizosphere of two alpine cushion plants and surrounding bare ground by employing a high throughput sequencing method targeting the V3 region of bacterial 16 S rRNA genes.Soil properties of the rhizosphere and the bare ground were also examined.We found that cushion rhizospheres harbored significantly more C,N,S,ammonia nitrogen,and soil moisture than the bare ground.Soil properties in cushion rhizospheres were not notably different,except for soil pH.Bacterial diversities within the same microhabitats did not vary significantly with seasons.We concluded that alpine cushion plants had positive effects on the rhizospheric bacterial communities,even though the strength of the effect varied in different cushion species.Cushion species and the soil sulfur content were probably the major factors driving the spatial distribution and structure of soil bacterial communities in the alpine communities dominated by cushion plants.
