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Hot-carrier transistors are a class of devices that leverage the excess kinetic energy of carriers. Unlike regular transistors, which rely on steady-state carrier transport, hot-carrier transistors modulate carriers to high-energy states, resulting in enhanced device speed and functionality. These characteristics are essential for applications that demand rapid switching and high-frequency operations, such as advanced telecommunications and cutting-edge computing technologies1-5. However, the traditional mechanisms of hot-carrier generation are either carrier injection6-11 or acceleration12,13, which limit device performance in terms of power consumption and negative differential resistance14-17. Mixed-dimensional devices, which combine bulk and low-dimensional materials, can offer different mechanisms for hot-carrier generation by leveraging the diverse potential barriers formed by energy-band combinations18-21. Here we report a hot-emitter transistor based on double mixed-dimensional graphene/germanium Schottky junctions that uses stimulated emission of heated carriers to achieve a subthreshold swing lower than 1 millivolt per decade beyond the Boltzmann limit and a negative differential resistance with a peak-to-valley current ratio greater than 100 at room temperature. Multi-valued logic with a high inverter gain and reconfigurable logic states are further demonstrated. This work reports a multifunctional hot-emitter transistor with significant potential for low-power and negative-differential-resistance applications, marking a promising advancement for the post-Moore era.
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Replacing traditional journals with a more modern solution is not a new idea. Here, we propose ways to overcome the social dilemma underlying the decades of inaction. Any solution needs to not only resolve the current problems but also be capable of preventing takeover by corporations: it needs to replace traditional journals with a decentralized, resilient, evolvable network that is interconnected by open standards and open-source norms under the governance of the scholarly community. It needs to replace the monopolies connected to journals with a genuine, functioning and well-regulated market. In this new market, substitutable service providers compete and innovate according to the conditions of the scholarly community, avoiding sustained vendor lock-in. Therefore, a standards body needs to form under the governance of the scholarly community to allow the development of open scholarly infrastructures servicing the entire research workflow. We propose a redirection of money from legacy publishers to the new network by funding bodies broadening their minimal infrastructure requirements at recipient institutions to include modern infrastructure components replacing and complementing journal functionalities. Such updated eligibility criteria by funding agencies would help realign the financial incentives for recipient institutions with public and scholarly interest.
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Integrating a graphene transparent electrode (TE) matrix with driving circuits is essential for the practical use of graphene in optoelectronics such as active-matrix organic light-emitting diode (OLED) display, however it is disabled by the transport of carriers between graphene pixels after deposition of a semiconductor functional layer caused by the atomic thickness of graphene. Here, the carrier transport regulation of a graphene TE matrix by using an insulating polyethyleneimine (PEIE) layer is reported. The PEIE forms an ultrathin uniform film (≤10 nm) to fill the gap of the graphene matrix, blocking horizontal electron transport between graphene pixels. Meanwhile, it can reduce the work function of graphene, improving the vertical electron injection through electron tunneling. This enables the fabrication of inverted OLED pixels with record high current and power efficiencies of 90.7 cd A-1 and 89.1 lm W-1 , respectively. By integrating these inverted OLED pixels with a carbon nanotube-based thin-film transistor (CNT-TFT)-driven circuit, an inch-size flexible active-matrix OLED display is demonstrated, in which all OLED pixels are independently controlled by CNT-TFTs. This research paves a way for the application of graphene-like atomically thin TE pixels in flexible optoelectronics such as displays, smart wearables, and free-form surface lighting.
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Highly conductive concrete/mortar has been long pursued to realize structural health monitoring in the development of smart-cement-based facilities. However, it remains challenging to significantly increase the electrical conductivity of concrete/mortar without lowering the compressive strength and flowability. Here, nanocrystalline-graphene-coated aggregates (termed Gr@AGs) are synthesized to break this conductivity-strength tradeoff. Admixing Gr@AGs with cement enables the construction of a conductive network of graphene that simultaneously strengthens the interfacial transition zone between aggregates and paste. As a result, high conductivity and improved mechanical properties have been simultaneously realized in Gr@AGs-based smart mortars. The significant positive effects of Gr@AGs are further enhanced by combining them with a low percentage of carbon fiber. Typically, the 28-day compressive/flexural strength of the optimized mortar increases by 12.2%/19.4%, with the electrical resistivity reduced by over 3 orders of magnitude from â¼4.6 × 105 to 182 Ω cm. On this basis, we demonstrate high-sensitivity cement-based piezoresistive sensors with a fractional change in resistivity as high as â¼25%, which is more than 1 order of magnitude higher than those reported in comparable systems. This study provides a solution to the critical issues in developing smart cementitious composites by taking full advantage of graphene's properties.
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We show that the knockout of a sugar transporter gene OsSWEET15 led to a significant drop in rice fertility with around half of the knockout mutant's spikelets bearing blighted or empty grains. The rest of the spikelets bore fertile grains with a slightly reduced weight. Notably, the ovaries in the blighted grains of the ossweet15 mutants expanded after flowering but terminated their development before the endosperm cellularization stage and subsequently aborted. ß- glucuronidase (GUS) and Green Fluorescent Protein (GFP) reporter lines representing the OsSWEET15 expression showed that the gene was expressed in the endosperm tissues surrounding the embryo, which supposedly supplies nutrients to sustain embryo development. These results together with the protein's demonstrated sucrose transport capacity and plasma membrane localization suggest that OsSWEET15 plays a prominent role during the caryopsis formation stage, probably by releasing sucrose from the endosperm to support embryo development. By contrast, the empty grains were probably caused by the reduced pollen viability of the ossweet15 mutants. Investigation of ossweet11 mutant grains revealed similar phenotypes to those observed in the ossweet15 mutants. These results indicate that both OsSWEET15 and OsSWEET11 play important and similar roles in rice pollen development, caryopsis formation and seed-setting, in addition to their function in seed-filling that was demonstrated previously.
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Oryza , Oryza/genética , Semillas/metabolismo , Endospermo/genética , Transporte Biológico , Glucuronidasa/metabolismo , Sacarosa/metabolismo , Proteínas de Plantas/metabolismoRESUMEN
Ambient solution-processed conductive materials with a sufficient low work function are essential to facilitate electron injection in electronic and optoelectronic devices but are challenging. Here, we design an electrically conducting and ambient-stable polymer electrolyte with an ultralow work function down to 2.2 eV, which arises from heavy n-doping of dissolved salts to polymer matrix. Such materials can be solution processed into uniform and smooth films on various conductors including graphene, conductive metal oxides, conducting polymers and metals to substantially improve their electron injection, enabling high-performance blue light-emitting diodes and transparent light-emitting diodes. This work provides a universal strategy to design a wide range of stable charge injection materials with tunable work function. As an example, we also synthesize a high-work-function polymer electrolyte material for high-performance solar cells.
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Sucrose-proton symporters play important roles in carbohydrate transport during plant growth and development. Their physiological functions have only been partly characterized and their regulation mechanism is largely unclear. Here we report that the knockout of a sucrose transporter gene, OsSUT1, by CRISPR-Cas9 mediated gene editing resulted in a slightly dwarf size and complete infertility of the gene's homozygous mutants. Observation of caryopsis development revealed that the endosperm of OsSUT1 mutants failed to cellularize and did not show any sign of seed-filling. Consistently, OsSUT1 was identified to express strongly in developing caryopsis of wild-type rice, particularly in the nucellar epidermis and aleurone which are critical for the uptake of nutrients into the endosperm. These results indicate that OsSUT1 is indispensable during the rice reproductive stage particularly for caryopsis development. Interestingly, OsSUT1 possesses at least 6 alternative splicing transcripts, including the 4 transcripts deposited previously and the other two identified by us. The differences among these transcripts primarily lie in their coding region of the 3' end and 3' UTR region. Real-time PCR showed that 4 of the 6 transcripts had different expressional patterns during rice vegetative and reproductive growth stages. Given the versatility of the gene, addressing its alternative splicing mechanism may expand our understanding of SUT's function substantially.
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Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Fertilidad/genética , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Oryza/genética , Oryza/metabolismo , Sacarosa/metabolismo , Empalme Alternativo , Productos Agrícolas/genética , Productos Agrícolas/metabolismo , Grano Comestible/genética , Grano Comestible/metabolismo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Variación Genética , Genotipo , Semillas/crecimiento & desarrolloRESUMEN
The conventional strategy of fabricating resistive random access memory (RRAM) based on graphene oxide is limited to a resistive layer with homogeneous oxidation, and the switching behavior relies on its redox reaction with an active metal electrode, so the obtained RRAMs are typically plagued by inferior performance and reliability. Here, we report a strategy to develop high-performance flexible RRAMs by using graphene oxidized with a perpendicular oxidation gradient as the resistive layer. In contrast to a homogeneous oxide, this graphene together with its distinctive inter-layer oxygen diffusion path enables excellent oxygen ion/vacancy diffusion. Without an interfacial redox reaction, oxygen ions can diffuse to form conductive filaments with two inert metal electrodes by applying a bias voltage. Compared with state-of-the-art graphene oxide RRAMs, these graphene RRAMs have shown superior performance including a high on-off current ratio of â¼105, long-term retention of â¼106 s, reproducibility over 104 cycles and long-term flexibility at a bending strain of 0.6%, indicating that the material has great potential in wearable smart data-storage devices.
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Graphene has emerged as an attractive candidate for flexible transparent electrode (FTE) for a new generation of flexible optoelectronics. Despite tremendous potential and broad earlier interest, the promise of graphene FTE has been plagued by the intrinsic trade-off between electrical conductance and transparency with a figure of merit (σDC/σOp) considerably lower than that of the state-of-the-art ITO electrodes (σDC/σOp <123 for graphene vs. â¼240 for ITO). Here we report a synergistic electrical/optical modulation strategy to simultaneously boost the conductance and transparency. We show that a tetrakis(pentafluorophenyl)boric acid (HTB) coating can function as highly effective hole doping layer to increase the conductance of monolayer graphene by sevenfold and at the same time as an anti-reflective layer to boost the visible transmittance to 98.8%. Such simultaneous improvement in conductance and transparency breaks previous limit in graphene FTEs and yields an unprecedented figure of merit (σDC/σOp â¼323) that rivals the best commercial ITO electrode. Using the tailored monolayer graphene as the flexible anode, we further demonstrate high-performance green organic light-emitting diodes (OLEDs) with the maximum current, power and external quantum efficiencies (111.4 cd A-1, 124.9 lm W-1 and 29.7%) outperforming all comparable flexible OLEDs and surpassing that with standard rigid ITO by 43%. This study defines a straightforward pathway to tailor optoelectronic properties of monolayer graphene and to fully capture their potential as a generational FTE for flexible optoelectronics.
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The aim of this study was to explore the main factors affecting the occurrence of dandruff in healthy people (nondisease-induced scalp desquamation). This study analyzed the fungal microbial diversity of the scalp in Chinese teenage volunteers and measured scalp sebum secretion, the scalp pH value, and scalp transepidermal water loss. The amount and size of dandruff were measured, and the main factors that influence dandruff in the normal population were identified using principal component analysis. The results showed that an increase in Malassezia restricta led to an increased amount of dandruff in the mild and moderate groups. Conversely, this was not found for individuals in the severe group, whose dandruff symptoms were influenced by scalp barrier function. In terms of dandruff area grouping, the pH value and the amount of sebum secretion were the main factors, with the barrier function and microbial diversity being secondary factors. Dandruff cosmetics should emphasize different treatments for different types of dandruff to achieve better antidandruff effects. The results of this study provide a new theoretical basis for the development of multiple targets for antidandruff agents aimed at the normal population.
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Caspa , Malassezia , Adolescente , Caspa/diagnóstico , Análisis Factorial , Humanos , Cuero CabelludoRESUMEN
The "call for help" hypothesis proposes that alarm calls produced by a bird can transmit warning information to both conspecific and interspecific neighbors. Neighbors who are attracted by social transmission might benefit from knowing about the presence of danger or by gaining information about the presence of predators or brood parasites nearby. Brood parasite hosts can distinguish threats from different intruders and exhibit varied responses correspondingly. However, most previous studies have conducted sound playback at host nest sites and focused on conspecific individuals attracted by the alarm calls. In this study, we used random location playback to investigate the responses of different host species to alarm signals of oriental reed warblers (Acrocephalus orientalis) toward different intruders (brood parasite, predator, and harmless control) in order to reveal how hosts evaluate different threats from different intruders using vocal information in non-nesting areas during the breeding season. We found that the alarm calls given in response to different intruders incurred similar numbers of approaching species for both conspecific and interspecific birds. However, the number of attracted individuals differed significantly among the various species, with conspecifics and vinous-throated parrotbills (Paradoxornis webbianus) dominating, both of which are major hosts of common cuckoos (Cuculus canorus). Nevertheless, interspecific birds did not present any aggressive behavior according to the alarm calls, which implied that visual information may be needed for further confirmation of threats. In addition, determining whether alarm call structure promoted an evolutionary convergence phenomenon still needs further verification.
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Aves/fisiología , Comportamiento de Nidificación/fisiología , Vocalización Animal/fisiología , Animales , Estaciones del Año , TerritorialidadRESUMEN
The advancement of Ni-Bi batteries has turned sluggish because of impenetrable barriers related to physicochemical instability of bismuthic species under thermal conditions. This directly makes Bi-based anodes impossible to hybridize with graphitic carbons for a longer-term cyclic lifespan. To break this constraint, we herein propose an effective strategy by incorporating Fe into bismuthic systems to form multielement anodes. The smart Bi/Fe merits combination/complementation can drastically promote the tolerable temperature of Bi-containing nanomaterials over 500 °C, enabling carbon encapsulation without altering their geometric properties and in the meantime endowing the anodes with inherited electrochemical superiorities. The as-built BiFeO3@carbon anodes exhibit prominent electrode performances with excellent electrochemical activity (both Bi- and Fe-based components act as faradaic redox reaction sites), excellent rate capabilities, and impressive capacity retention (â¼83.4% after 2000 cycles). We further unveil the anodic phase conversions of "BiFeO3 â Bi2O3/Fe2O3" (via the transition state of Bi2O3(222)) based on the real-time characterizations/post-analysis at distinct cyclic stages. The packed full cells exhibit max. energy/power densities of â¼90.72 W h kg-1/â¼1.3 kW kg-1. Our study may offer a promising engineering route to promote the development of safe and applicable Ni-Bi batteries in near-future applications.
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Smart combination of manifold carbonaceous materials with admirable functionalities (like full of pores/functional groups, high specific surface area) is still a mainstream/preferential way to address knotty issues of polysulfides dissolution/shuttling and poor electrical conductivity for S-based cathodes. However, extensive use of conductive carbon fillers in cell designs/technology would induce electrolytic overconsumption and thereby shelve high-energy-density promise of Li-S cells. To cut down carbon usage, we propose the incorporation of multi-functionalized NiFe2O4 quantum dots (QDs) as affordable additive substitutes. The total carbon content can be greatly curtailed from 26% (in traditional S/C cathodes) to a low/commercial mass ratio (~ 5%). Particularly, note that NiFe2O4 QDs additives own superb chemisorption interactions with soluble Li2Sn molecules and proper catalytic features facilitating polysulfide phase conversions and can also strengthen charge-transfer capability/redox kinetics of overall cathode systems. Benefiting from these intrinsic properties, such hybrid cathodes demonstrate prominent rate behaviors (decent capacity retention with ~ 526 mAh g-1 even at 5 A g-1) and stable cyclic performance in LiNO3-free electrolytes (only ~ 0.08% capacity decay per cycle in 500 cycles at 0.2 A g-1). This work may arouse tremendous research interest in seeking other alternative QDs and offer an economical/more applicable methodology to construct low-carbon-content electrodes for practical usage.
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Ab initio protein tertiary structure prediction is one of the long-standing problems in structural bioinformatics. With the help of residue-residue contact and secondary structure prediction information, the accuracy of ab initio structure prediction can be enhanced. In this study, an improved differential evolution with secondary structure and residue-residue contact information referred to as SCDE is proposed for protein structure prediction. In SCDE, two score models based on secondary structure and contact information are proposed, and two selection strategies, namely, secondary structure-based selection strategy and contact-based selection strategy, are designed to guide conformation space search. A probability distribution function is designed to balance these two selection strategies. Experimental results on a benchmark dataset with 28 proteins and four free model targets in CASP12 demonstrate that the proposed SCDE is effective and efficient.
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Biología Computacional/métodos , Estructura Secundaria de Proteína , Proteínas , Algoritmos , Bases de Datos de Proteínas , Proteínas/química , Proteínas/genéticaRESUMEN
De novo protein structure prediction can be treated as a conformational space optimization problem under the guidance of an energy function. However, it is a challenge of how to design an accurate energy function which ensures low-energy conformations close to native structures. Fortunately, recent studies have shown that the accuracy of de novo protein structure prediction can be significantly improved by integrating the residue-residue distance information. In this paper, a two-stage distance feature-based optimization algorithm (TDFO) for de novo protein structure prediction is proposed within the framework of evolutionary algorithm. In TDFO, a similarity model is first designed by using feature information which is extracted from distance profiles by bisecting K-means algorithm. The similarity model-based selection strategy is then developed to guide conformation search, and thus improve the quality of the predicted models. Moreover, global and local mutation strategies are designed, and a state estimation strategy is also proposed to strike a trade-off between the exploration and exploitation of the search space. Experimental results of 35 benchmark proteins show that the proposed TDFO can improve prediction accuracy for a large portion of test proteins.
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Algoritmos , Biología Computacional/métodos , Conformación Proteica , Proteínas/química , Inteligencia Artificial , Modelos Moleculares , Mutación/genética , Proteínas/genéticaRESUMEN
The major accomplishment of electrochemical energy-storage devices is closely linked to the advent of state-of-the-art techniques to make optimal electrode systems. Herein, we demonstrate a unique popcorn-inspired strategy to develop all-conductive and highly puffed Feâcarbon nanopopcorns as superb anodes for rechargeable Ni/Fe batteries. Temperature-dependent systematic studies show that the nanopopcorn evolution mechanism is governed by typical phase variation from Fe2O3 nanospheres to dispersed Fe0 nanodebris, whose formation induces catalytic reconstruction/conversion from hydrocarbons to graphitic nanolayers while triggering the explosion-like instant puffing process beyond 700 °C. The as-built Feâcarbon hybrids with favorable loosened structures, open-up/enlarged surface areas, and intrinsically conducting nature enable great electrochemical reactivity and cyclic stability (reversible capacity higher than â¼420 mA h g-1 in all cycles without obvious capacity decay), as well as outstanding rate behaviors (â¼300 mA h g-1 is still retained at â¼20 A g-1). Full-cell devices of NiO@carbon (+)//Feâcarbon (-) can exhibit Max. energy/power densities of up to â¼140.8 W h kg-1 and â¼15.6 kW kg-1, respectively. This work sheds a fundamental light on arts to configure puffed electrodes for advanced electrodes in various important applications while holding great promise for high-rate/capacity aqueous rechargeable batteries.
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Peer review is a process used in the selection of manuscripts for journal publication and proposals for research grant funding. Though widely used, peer review is not without flaws and critics. Performing large-scale experiments to evaluate and test correctives and alternatives is difficult, if not impossible. Thus, many researchers have turned to simulation studies to overcome these difficulties. In the last 10 years this field of research has grown significantly but with only limited attempts to integrate disparate models or build on previous work. Thus, the resulting body of literature consists of a large variety of models, hinging on incompatible assumptions, which have not been compared, and whose predictions have rarely been empirically tested. This scoping review is an attempt to understand the current state of simulation studies of peer review. Based on 46 articles identified through literature searching, we develop a proposed taxonomy of model features that include model type (e.g. formal models vs. ABMs or other) and the type of modeled peer review system (e.g. peer review in grants vs. in journals or other). We classify the models by their features (including some core assumptions) to help distinguish between the modeling approaches. Finally, we summarize the models' findings around six general themes: decision-making, matching submissions/reviewers, editorial strategies; reviewer behaviors, comparisons of alternative peer review systems, and the identification and addressing of biases. We conclude with some open challenges and promising avenues for future modeling work.
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Pyrite FeS2 has long been a research focus as the alternative anode of rechargeable Ni-Fe cells owing to its eye-catching merits of great earth-abundance, attractive electrical conductivity, and output capacity. However, its further progress is impeded by unsatisfactory cyclic behaviors due to still "ill-defined" phase changes. To gain insights into the pyrite working principles/failure factors, we herein design a core-shell hybrid of a FeS2@carbon nanoreactor, an optimal anode configuration approaching the practical usage state. The resultant electrodes exhibit a Max. specific capacity of â¼272.89 mAh g-1 (at â¼0.81 A g-1), remarkably improved cyclic longevity/stability (beyond â¼80% capacity retention after 103 cycles) and superior rate capability (â¼146.18 mAh g-1 is remained at â¼20.01 A g-1) in contrast to bare FeS2 counterparts. The as-built Ni-Fe full cells can also output impressive specific energy/power densities of â¼87.38 Wh kg-1/ â¼ 11.54 kW kg-1. Moreover, a refreshed redox reaction working mechanism of "FeS2OH âFeS2âFe0(in pyrite domains)" is redefined based on real-time electrode characterizations at distinct operation stages. In a total cyclic period, the configured pyrite-based anodes would stepwise undergo three critical stages nominally named "retention", "phase transition/coexistence", and "degradation", each of which is closely related to variations on anodic compositions/structures. Combined with optimal electrode configurations and in-depth clarifications on inherent phase conversions, this focus study may guide us to maximize the utilization efficiency of pyrite for all other aqueous electrochemical devices.
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Li-S batteries have triggered global research interest because of their higher theoretical energy density and lower cost than popularized Li-ion cells. However, they still do not have practical implementations because of issues induced by intermediate polysulfide dissolution. To better confine both S and polysulfides in cathode regions and prolong the cyclic lifespan, we purposely design the unique highly puffed Co9S8/carbon nanofibers (Co9S8@CNFs) as efficient S carriers. Such fibrous products made of interconnected hollow/porous Co9S8/C nanopolyhedra can provide ample places to load the large amount of S, convenient pathways for both Li+ and electrons transfer, and extra reversible capacity contribution. Particularly, each individual Co9S8 subunit is physically robust, metallic, and polarized, synergistically enabling the spatial confinement and chemical bonding to restrict S volume expansions and anchor the soluble polysulfides during cycling. The as-built highly puffed SâCo9S8@CNFs cathodes can exhibit a large specific capacity of â¼1080 mA h g-1, admirable cyclic stability/lifespan (capacity loss rate: â¼0.03% per cycle), and excellent rate capabilities. Our work may hold a great potential in rational design of superior cathodes for applicable Li-S cell systems.
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Protein structure prediction has been a long-standing problem for the past decades. In particular, the loop region structure remains an obstacle in forming an accurate protein tertiary structure because of its flexibility. In this study, Rama torsion angle and secondary structure feature-guided differential evolution named RSDE is proposed to predict three-dimensional structure with the exploitation on the loop region structure. In RSDE, the structure of the loop region is improved by the following: loop-based cross operator, which interchanges configuration of a randomly selected loop region between individuals, and loop-based mutate operator, which considers torsion angle feature into conformational sampling. A stochastic ranking selective strategy is designed to select conformations with low energy and near-native structure. Moreover, the conformational resampling method, which uses previously learned knowledge to guide subsequent sampling, is proposed to improve the sampling efficiency. Experiments on a total of 28 test proteins reveals that the proposed RSDE is effective and can obtain native-like models.