This paper offers a general review and comparative analysis of various types of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technologies. It evaluates the strengths and weaknesses of these techn...This paper offers a general review and comparative analysis of various types of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technologies. It evaluates the strengths and weaknesses of these technologies to identify the optimal approach for conducting genetic screens. Through an extensive literature review, this paper examines CRISPR nuclease, CRISPR activation (CRISPRa), and CRISPR interference (CRISPRi) screens. This study concludes that CRISPRa and CRISPRi are more advantageous due to their use of deactivated Cas9 proteins that only over-express or deactivate genes rather than irreversibly breaking genes like CRISPRn. Notably, CRISPRa is unique in its ability to over-express genes, while the other two technologies deactivate genes. Future studies may focus on inducing multiple mutations simultaneously—both gain-of-function and gene knockout—to carry out a more complete screen that can test the combinatorial effect of genes. Likewise, targeting both exons and introns can offer a more thorough understanding of a specific phenotype.展开更多
With the invention of the aircraft, it has become much faster and larger than the original Wright Brothers aircraft. When the speed is high enough to cross the speed of sound, air conditions will be different than tha...With the invention of the aircraft, it has become much faster and larger than the original Wright Brothers aircraft. When the speed is high enough to cross the speed of sound, air conditions will be different than that in low speed due to the existence of shock wave. In this work, we introduce several numerical ways to analyze the performance of the airfoil when the speed is higher than the speed of sound. With these numerical methods, we analyzed the performance of diamond-shaped airfoil under different angles of attack and speed. With this data, engineers can choose a better airfoil to attain a lower drag coefficient as well as lift coefficient when designing a high-speed aircraft.展开更多
This research is based on writer’s experience of teaching about 30 elders in smartphone classes over the course of 6 months at a community in Shanghai.Cognitive linguistic phenomena in the teaching process are discus...This research is based on writer’s experience of teaching about 30 elders in smartphone classes over the course of 6 months at a community in Shanghai.Cognitive linguistic phenomena in the teaching process are discussed.The elders’lack the lexicon and context of this internet age leads to low learning efficiency and inability of self-studying.The use of referential language accommodation,a specific kind of language simplification,by the teachers,poses potential psychological harm of to the elders.This research concludes that starting classes by“lexicon and context”as the basis for subsequent classes can solve both problems.The phenomenon and causes of elders’unconscious“egocentricity”are also discussed.Teachers should present understanding as tolerance may alleviate elder egocentricity.展开更多
The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are ke...The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are key factors in exploration of ferroelectricity in fluorite-type oxide HfO_(2) films.Here we investigate the structures and straininduced ferroelectric transition in different phases of few-layer HfO_(2) films(layer number𝑁=1–5).It is found that HfO_(2) films for all phases are more stable with increasing films thickness.Among them,the Pmn2_(1)(110)-oriented film is most stable,and the films of𝑁=4,5 occur with a𝑃21 ferroelectric transition under tensile strain,resulting in polarization about 11.8μC/cm^(2) along in-plane𝑎-axis.The ferroelectric transition is caused by the strain,which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions,accompanied by the change of surface Hf–O bond lengths.More importantly,three new stable HfO_(2)2D structures are discovered,together with analyses of computed electronic structures,mechanical,and dielectric properties.This work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO_(2) films.展开更多
PTC heating is the new energy vehicle heat management system of the main heating mode,this paper a detailed analysis of the basic working principle of the PTC heater,the design of the PTC heater hardware control syste...PTC heating is the new energy vehicle heat management system of the main heating mode,this paper a detailed analysis of the basic working principle of the PTC heater,the design of the PTC heater hardware control system and software control system,with MALTAB simulation of the control system model.展开更多
One of the common problems for L2 learners in ESL reading is that the text is either too difficult to understand or too simple to challenge,particularly the extracurricular reading material.The Little Prince and Pride...One of the common problems for L2 learners in ESL reading is that the text is either too difficult to understand or too simple to challenge,particularly the extracurricular reading material.The Little Prince and Pride and Prejudice are typically listed in the key reading materials for L2 learners.Contrary to the popularity,a large number of L2 learners find it is hard to complete due to the low text coverage with existing vocabulary.The corpus has become an important language research tool to store language materials according to the specific goals and the way through certain technical means.This paper is going to explore the text coverage of The Little Prince and Pride and Prejudice by range analysis,and comparing with English Curriculum Standards to figure out suitable reading targets of these two materials.展开更多
Recently,international media reported the emergence of a new“superbug”on the International Space Station that has mutated under the closed,extreme conditions of the station.Thus,the following questions arise:How did...Recently,international media reported the emergence of a new“superbug”on the International Space Station that has mutated under the closed,extreme conditions of the station.Thus,the following questions arise:How did bacterial and other microbial communities appear on the space station?Why can they not be completely eradicated?What are the current methods to prevent pathogen contamination for ensuring the health and safety of astronauts?They are no answers yet.展开更多
Objectives To investigate the sterilization effects of carbon quantum dots(CDs)exhibiting red fluorescence(denoted as SG-CDs)on various bacteria Methods SG-CDs were prepared using a one-step high-pressure method with ...Objectives To investigate the sterilization effects of carbon quantum dots(CDs)exhibiting red fluorescence(denoted as SG-CDs)on various bacteria Methods SG-CDs were prepared using a one-step high-pressure method with glucose and porphyrin ring derivatives as raw materials.The three antibacterial materials were SG-CDs(2000 mg/L),hypochlorous acid(2000 mg/L),and iodophor(2000 mg/L),and the five American standard bacterial strains were Staphylococcus aureus(Sau),Pseudomonas aeruginosa(Pae),Escherichia coli(Eco),Enterobacter cloacae(Ecl),and Klebsiella pneumoniae(Kpn).Each of the five bacteria was added separately to cation-adjusted Mueller–Hinton broths containing all three antibacterial ingredients and then incubated for 8 h at 35℃.After incubation,the bacteria were coated on an enrichment medium and incubated overnight at 35℃.The colony forming units in the culture medium were counted,and the sterilization effects of SG-CDs in the experimental group,positive control group,and quality-control group were compared.Results The bactericidal activity of SG-CDs against all five drug-resistant bacteria(mortality rate≥99.9%)was equivalent to that of hypochlorite but higher than that of iodophor.At the same concentration,the bactericidal activity of SG-CDs against Sau,Pae,and Eco was twice that of iodine,while the bactericidal activity of SG-CDs against Ecl and Kpn was four times that of iodine.Conclusions In conclusion,SG-CDs showed significant bactericidal activity against five types of bacteria,namely Sau,Pae,Eco,Ecl,and Kpn.CDs exhibiting red fluorescence have the potential to replace antibiotics and overcome bacterial drug resistance,serving as important medicines for treating bacterial infections and wounds.展开更多
文摘This paper offers a general review and comparative analysis of various types of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technologies. It evaluates the strengths and weaknesses of these technologies to identify the optimal approach for conducting genetic screens. Through an extensive literature review, this paper examines CRISPR nuclease, CRISPR activation (CRISPRa), and CRISPR interference (CRISPRi) screens. This study concludes that CRISPRa and CRISPRi are more advantageous due to their use of deactivated Cas9 proteins that only over-express or deactivate genes rather than irreversibly breaking genes like CRISPRn. Notably, CRISPRa is unique in its ability to over-express genes, while the other two technologies deactivate genes. Future studies may focus on inducing multiple mutations simultaneously—both gain-of-function and gene knockout—to carry out a more complete screen that can test the combinatorial effect of genes. Likewise, targeting both exons and introns can offer a more thorough understanding of a specific phenotype.
文摘With the invention of the aircraft, it has become much faster and larger than the original Wright Brothers aircraft. When the speed is high enough to cross the speed of sound, air conditions will be different than that in low speed due to the existence of shock wave. In this work, we introduce several numerical ways to analyze the performance of the airfoil when the speed is higher than the speed of sound. With these numerical methods, we analyzed the performance of diamond-shaped airfoil under different angles of attack and speed. With this data, engineers can choose a better airfoil to attain a lower drag coefficient as well as lift coefficient when designing a high-speed aircraft.
文摘This research is based on writer’s experience of teaching about 30 elders in smartphone classes over the course of 6 months at a community in Shanghai.Cognitive linguistic phenomena in the teaching process are discussed.The elders’lack the lexicon and context of this internet age leads to low learning efficiency and inability of self-studying.The use of referential language accommodation,a specific kind of language simplification,by the teachers,poses potential psychological harm of to the elders.This research concludes that starting classes by“lexicon and context”as the basis for subsequent classes can solve both problems.The phenomenon and causes of elders’unconscious“egocentricity”are also discussed.Teachers should present understanding as tolerance may alleviate elder egocentricity.
基金supported by the National Key R&D Program of China(Grant No.2023YFB4402600)the National Natural Science Foundation of China(Grant Nos.12074241,11929401,52130204,12311530675,and 52271007)+5 种基金Key Research Project of Zhejiang Lab(Grant No.2021PE0AC02)Science and Technology Commission of Shanghai Municipality(Grant Nos.22XD1400900,20501130600,21JC1402700,and 21JC1402600)supports from the open projects of Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Anhui University of Technology),Ministry of Education(Grant No.GFST2022KF08)State Key Laboratory of Surface Physics(Fudan University)(Grant No.KF202210)State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences(Grant No.SITP-NLIST-YB-2022-08)the support of China Scholarship Council,and thanks Mr.Xiaowen Shi(from HZWTECH)for helpful discussions.
文摘The discovery of ferroelectricity in HfO_(2)-based materials with high dielectric constant has inspired tremendous research interest for next-generation electronic devices.Importantly,films structure and strain are key factors in exploration of ferroelectricity in fluorite-type oxide HfO_(2) films.Here we investigate the structures and straininduced ferroelectric transition in different phases of few-layer HfO_(2) films(layer number𝑁=1–5).It is found that HfO_(2) films for all phases are more stable with increasing films thickness.Among them,the Pmn2_(1)(110)-oriented film is most stable,and the films of𝑁=4,5 occur with a𝑃21 ferroelectric transition under tensile strain,resulting in polarization about 11.8μC/cm^(2) along in-plane𝑎-axis.The ferroelectric transition is caused by the strain,which induces the displacement of Hf and O atoms on the surface to non-centrosymmetric positions away from the original paraelectric positions,accompanied by the change of surface Hf–O bond lengths.More importantly,three new stable HfO_(2)2D structures are discovered,together with analyses of computed electronic structures,mechanical,and dielectric properties.This work provides guidance for theoretical and experimental study of the new structures and strain-tuned ferroelectricity in freestanding HfO_(2) films.
文摘PTC heating is the new energy vehicle heat management system of the main heating mode,this paper a detailed analysis of the basic working principle of the PTC heater,the design of the PTC heater hardware control system and software control system,with MALTAB simulation of the control system model.
文摘One of the common problems for L2 learners in ESL reading is that the text is either too difficult to understand or too simple to challenge,particularly the extracurricular reading material.The Little Prince and Pride and Prejudice are typically listed in the key reading materials for L2 learners.Contrary to the popularity,a large number of L2 learners find it is hard to complete due to the low text coverage with existing vocabulary.The corpus has become an important language research tool to store language materials according to the specific goals and the way through certain technical means.This paper is going to explore the text coverage of The Little Prince and Pride and Prejudice by range analysis,and comparing with English Curriculum Standards to figure out suitable reading targets of these two materials.
文摘Recently,international media reported the emergence of a new“superbug”on the International Space Station that has mutated under the closed,extreme conditions of the station.Thus,the following questions arise:How did bacterial and other microbial communities appear on the space station?Why can they not be completely eradicated?What are the current methods to prevent pathogen contamination for ensuring the health and safety of astronauts?They are no answers yet.
文摘Objectives To investigate the sterilization effects of carbon quantum dots(CDs)exhibiting red fluorescence(denoted as SG-CDs)on various bacteria Methods SG-CDs were prepared using a one-step high-pressure method with glucose and porphyrin ring derivatives as raw materials.The three antibacterial materials were SG-CDs(2000 mg/L),hypochlorous acid(2000 mg/L),and iodophor(2000 mg/L),and the five American standard bacterial strains were Staphylococcus aureus(Sau),Pseudomonas aeruginosa(Pae),Escherichia coli(Eco),Enterobacter cloacae(Ecl),and Klebsiella pneumoniae(Kpn).Each of the five bacteria was added separately to cation-adjusted Mueller–Hinton broths containing all three antibacterial ingredients and then incubated for 8 h at 35℃.After incubation,the bacteria were coated on an enrichment medium and incubated overnight at 35℃.The colony forming units in the culture medium were counted,and the sterilization effects of SG-CDs in the experimental group,positive control group,and quality-control group were compared.Results The bactericidal activity of SG-CDs against all five drug-resistant bacteria(mortality rate≥99.9%)was equivalent to that of hypochlorite but higher than that of iodophor.At the same concentration,the bactericidal activity of SG-CDs against Sau,Pae,and Eco was twice that of iodine,while the bactericidal activity of SG-CDs against Ecl and Kpn was four times that of iodine.Conclusions In conclusion,SG-CDs showed significant bactericidal activity against five types of bacteria,namely Sau,Pae,Eco,Ecl,and Kpn.CDs exhibiting red fluorescence have the potential to replace antibiotics and overcome bacterial drug resistance,serving as important medicines for treating bacterial infections and wounds.
