The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variatio...The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity(H′) index was used to estimate phenotypic diversity. The estimated H′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest(0.86) H′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest(0.72) and lowest(0.44) H′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest(0.76) and lowest(0.62) H′ values were recorded for altitudes 1600–2000and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.展开更多
While much attention has been given to bio-robotics in recent years, not much of this has been given to the challenging subject of locomotion in slippery conditions. This study begins to rectify this by proposing a bi...While much attention has been given to bio-robotics in recent years, not much of this has been given to the challenging subject of locomotion in slippery conditions. This study begins to rectify this by proposing a biomimetic approach to generating the friction required to give sufficient propulsive force on a slippery substrate. We took inspiration from a successful biological solution-that of applying hair-like structures to the propulsive appendages, similar to the setae found in nereid polychaetes living in muddy habitats. We began by examining the morphology and the mean locomotion parameters of one of the most common nereids.. Nereis diversicolor. Following this study, we designed and fabricated a robotic system with appendages imitating the biological shape found in the worm. A flexible control system was developed to allow most of the locomotion parameters observed in the real worm to be applied to the robot. Experiments on three different natural substrates ranging from fine sand to gravel showed that, whereas a plate attached to the appendage generated most thrust on a small particle substrate, a bundle of artificial setae attached to the appendage generated most thrust on a large particle substrate. On all types of substrate tested, an appendage without any attachment did significantly worse than one with. This suggests that hair-like structures can be advantageous.展开更多
As non-photosynthesizing organs, roots are dependent on diffusion of oxygen from the external environment and, in some in stances, from the shoot for their aerobic metabolism . Establishment of hypoxic niches in the d...As non-photosynthesizing organs, roots are dependent on diffusion of oxygen from the external environment and, in some in stances, from the shoot for their aerobic metabolism . Establishment of hypoxic niches in the developing tissues of plants has been postulated as a consequence of insufficient diffusion of oxygen to satisfy the demands throughout development. Here, we report that such niches are established at specific stages of lateral root primordia development in Arabidopsis thaliana grown under aerobic conditions. Using gain- and loss-of-function mutants, we show that ERF-Ⅶ transcription factors, which mediate hypoxic responses, control root architecture by acting in cells with a high level of auxin signaling. ERF-Ⅶs repress the expression of the auxin-induced genes LBD16, LBD18, and PUCHI, which are essential for lateral root development, by binding to their promoters. Our results support a model in which the establishment of hypoxic n iches in the developing lateral root primordia con tributes to the shutting down of key auxin-induced genes and regulates the production of lateral roots.展开更多
The drought-tolerant grass Brachypodium distachyon is an emerging model species for temperate grasses and cereal crops. To explore the usefulness of this species for drought studies, a reproducible in vivo drought ass...The drought-tolerant grass Brachypodium distachyon is an emerging model species for temperate grasses and cereal crops. To explore the usefulness of this species for drought studies, a reproducible in vivo drought assay was developed. Spontaneous soil drying led to a 45% reduction in leaf size, and this was mostly due to a decrease in cell expansion, whereas cell division remained largely unaffected by drought. To investigate the molecular basis of the observed leaf growth reduction, the third Brachypodium leaf was dissected in three zones, namely proliferation, expan- sion, and mature zones, and subjected to transcriptome analysis, based on a whole-genome tiling array. This approach allowed us to highlight that transcriptome profiles of different developmental leaf zones respond differently to drought. Several genes and functional processes involved in drought tolerance were identified. The transcriptome data suggest an increased energy availability in the proliferation zones, along with an up-regulation of sterol synthesis that may influ-ence membrane fluidity. This information may be used to improve the tolerance of temperate cereals to drought, which is undoubtedly one of the major environmental challenges faced by agriculture today and in the near future.展开更多
Nature and technology often adopt structures that can be described as tubular helical assemblies.However,the role and mechanisms of these structures remain elusive.In this paper,we study the mechanical response under ...Nature and technology often adopt structures that can be described as tubular helical assemblies.However,the role and mechanisms of these structures remain elusive.In this paper,we study the mechanical response under compression and extension of a tubular assembly composed of 8 helical Kirchholf rods,arranged in pairs with opposite chirality and connected by pin joints,both analytically and numerically.We first focus on compression and find that,whereas a single helical rod would buckle,the rods of the assembly deform coherently as stable helical shapes wound around a common axis.Moreover,we investigate the response of the assembly under different boundary conditions,highlighting the emergence of a central region where rods remain circular helices.Secondly,we study the effects of different hypotheses on the elastic properties of rods,i.e.,stress-free rods when straight versus when circular helices,Kirchhoff’s rod model versus Sadowsky’s ribbon model.Summing up,our findings highlight the key role of mutual interactions in generating a stable ensemble response that preserves the helical shape of the individual rods,as well as some interesting features,and they shed some light on the reasons why helical shapes in tubular assemblies are so common and persistent in nature and technology.展开更多
Plant responses to drought are regulated by complex genetic and epigenetic networks leading to rapid reprogramming of plant growth, miRNAs have been widely indicated as key players in the regulation of growth and deve...Plant responses to drought are regulated by complex genetic and epigenetic networks leading to rapid reprogramming of plant growth, miRNAs have been widely indicated as key players in the regulation of growth and development. The role of miRNAs in drought response was investigated in young leaves of Brachypodium dis- tachyon, a drought-tolerant monocot model species. Adopting an in vivo drought assay, shown to cause a dramatic reduction in leaf size, mostly due to reduced cell expansion, small RNA libraries were produced from proliferating and expanding leaf cells. Next-generation sequencing data were analyzed using an in-house bioinformatics pipeline allowing the identification of 66 annotated miRNA genes and 122 new high confidence predictions greatly expand- ing the number of known Brachypodium miRNAs. In addition, we identified four TAS3 loci and a large number of siRNA-producing loci that show characteristics suggesting that they may represent young miRNA genes. Most miR- NAs showed a high expression level, consistent with their involvement in early leaf development and cell identity. Proliferating and expanding leaf cells respond differently to drought treatment and differential expression analyses suggest novel evidence for an miRNA regulatory network controlling cell division in both normal and stressed condi-tions and demonstrate that drought trigger a genetic reprogramming of leaf growth in which miRNAs are deeply involved.展开更多
The capsule robot(CR)is a promising endoscopic method in gastrointestinal diagnosis because of its low discomfort to users.Most CRs are used to acquire image information only and lack the ability to collect samples.Al...The capsule robot(CR)is a promising endoscopic method in gastrointestinal diagnosis because of its low discomfort to users.Most CRs are used to acquire image information only and lack the ability to collect samples.Although some biopsy capsule robots(BCRs)have been developed,it remains challenging to acquire the intestinal tissue while avoiding tearing and adhesion due to the flexibility of colonic tissue.In this study,we develop a BCR with a novel sampling strategy in which soft tissue is scratched with sharp blades rotating at high speed to avoid tissue tearing.In the BCR design,a spiral spring with prestored energy is used to release high energy within a short period of time,which is dificult for a motor or magnet to perform within a small capacity installation space.The energy of the tightened spiral spring is transmitted to drive sharp blades to rotate quickly via a designed gear mechanism.To guarantee reliable sampling,a Bowden cable is used to transmit the user's manipulation to trigger the rotation of the blades,and the triggering force transmitted by the able can be monitored in real time by a force sensor installed at the manipulating end.A prototype of the proposed BCR is designed and fabricated,and its performance is tested through in vitro experiments.The results show that the proposed BCR is effective and the size of its acquired samples satisfies dinical requirements.展开更多
We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes be...We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes between the arms of the MZI, achieved by signal modulation on one of the arms of the interferometer together with pseudoheterodyne detection, and it allows us to avoid the use of costly equipment such as tunable light sources or spectrum analyzers. The obtained output signal is intrinsically independent of wavelength, power variations, and global thermal variations, making it extremely robust and adequate for use in real conditions. Using a silicon-on-insulator MZI, we demonstrate the real-time monitoring of refractive index variations and achieve a detection limit of 4.1 × 10^(-6)refractive index units(RIU).展开更多
Tens of crawling bio-robots with cockroaches as the mobile platform have been developed with various functions.Compared with artificial crawling robots of the same size,they revealed better flexibility,larger payload,...Tens of crawling bio-robots with cockroaches as the mobile platform have been developed with various functions.Compared with artificial crawling robots of the same size,they revealed better flexibility,larger payload,and stronger endurance.These features made bio-robots ideal for pipeline inspection scenarios because the advancements in locomotion mechanisms and efficient power systems are still hurdles for current artificial systems.In this study,we controlled the bio-robot to crawl in the confined dark pipeline and achieved autonomous motion control with the help of an onboard sensing system.Specifically,a micro-camera was mounted on the electronic backpack of the cockroach for image collection,and an IMU sensor was used to compute its body orientation.The electronic backpack transmitted images to the host computer for junction recognition and distance estimation.Meanwhile,the insect's habituation to electrical stimulation has long been an uncertain factor in the control of bio-robots.Here,a synergistic stimulation strategy was proposed to markedly reduce the habituation and increase the number of effective turning controls to over 100 times.It is also found that both the increase of payload and the application of stimulations could promote the metabolic rate by monitoring carbon dioxide release.With the integration of synergistic stimulation and autonomous control,we demonstrated the fully autonomous pipeline navigation with our cockroach bio-robot,which realized the cycle number of approximately 10 in a roll.This research provides a novel technology that has the potential for practical applications in the future.展开更多
基金done through joint project between Mekelle University and Scuola Superiore Sant'Anna and the joint grant number is CDANR/ SSSA/42/2011The first author is further indebted to Scuola Superiore Sant'Anna, Italy for financial support given to the projectMekelle University for its support
文摘The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity(H′) index was used to estimate phenotypic diversity. The estimated H′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest(0.86) H′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest(0.72) and lowest(0.44) H′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest(0.76) and lowest(0.62) H′ values were recorded for altitudes 1600–2000and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.
文摘While much attention has been given to bio-robotics in recent years, not much of this has been given to the challenging subject of locomotion in slippery conditions. This study begins to rectify this by proposing a biomimetic approach to generating the friction required to give sufficient propulsive force on a slippery substrate. We took inspiration from a successful biological solution-that of applying hair-like structures to the propulsive appendages, similar to the setae found in nereid polychaetes living in muddy habitats. We began by examining the morphology and the mean locomotion parameters of one of the most common nereids.. Nereis diversicolor. Following this study, we designed and fabricated a robotic system with appendages imitating the biological shape found in the worm. A flexible control system was developed to allow most of the locomotion parameters observed in the real worm to be applied to the robot. Experiments on three different natural substrates ranging from fine sand to gravel showed that, whereas a plate attached to the appendage generated most thrust on a small particle substrate, a bundle of artificial setae attached to the appendage generated most thrust on a large particle substrate. On all types of substrate tested, an appendage without any attachment did significantly worse than one with. This suggests that hair-like structures can be advantageous.
文摘As non-photosynthesizing organs, roots are dependent on diffusion of oxygen from the external environment and, in some in stances, from the shoot for their aerobic metabolism . Establishment of hypoxic niches in the developing tissues of plants has been postulated as a consequence of insufficient diffusion of oxygen to satisfy the demands throughout development. Here, we report that such niches are established at specific stages of lateral root primordia development in Arabidopsis thaliana grown under aerobic conditions. Using gain- and loss-of-function mutants, we show that ERF-Ⅶ transcription factors, which mediate hypoxic responses, control root architecture by acting in cells with a high level of auxin signaling. ERF-Ⅶs repress the expression of the auxin-induced genes LBD16, LBD18, and PUCHI, which are essential for lateral root development, by binding to their promoters. Our results support a model in which the establishment of hypoxic n iches in the developing lateral root primordia con tributes to the shutting down of key auxin-induced genes and regulates the production of lateral roots.
文摘The drought-tolerant grass Brachypodium distachyon is an emerging model species for temperate grasses and cereal crops. To explore the usefulness of this species for drought studies, a reproducible in vivo drought assay was developed. Spontaneous soil drying led to a 45% reduction in leaf size, and this was mostly due to a decrease in cell expansion, whereas cell division remained largely unaffected by drought. To investigate the molecular basis of the observed leaf growth reduction, the third Brachypodium leaf was dissected in three zones, namely proliferation, expan- sion, and mature zones, and subjected to transcriptome analysis, based on a whole-genome tiling array. This approach allowed us to highlight that transcriptome profiles of different developmental leaf zones respond differently to drought. Several genes and functional processes involved in drought tolerance were identified. The transcriptome data suggest an increased energy availability in the proliferation zones, along with an up-regulation of sterol synthesis that may influ-ence membrane fluidity. This information may be used to improve the tolerance of temperate cereals to drought, which is undoubtedly one of the major environmental challenges faced by agriculture today and in the near future.
基金Open access funding provided by Scuola Superiore Sant’Anna within the CRUI-CARE Agreement.
文摘Nature and technology often adopt structures that can be described as tubular helical assemblies.However,the role and mechanisms of these structures remain elusive.In this paper,we study the mechanical response under compression and extension of a tubular assembly composed of 8 helical Kirchholf rods,arranged in pairs with opposite chirality and connected by pin joints,both analytically and numerically.We first focus on compression and find that,whereas a single helical rod would buckle,the rods of the assembly deform coherently as stable helical shapes wound around a common axis.Moreover,we investigate the response of the assembly under different boundary conditions,highlighting the emergence of a central region where rods remain circular helices.Secondly,we study the effects of different hypotheses on the elastic properties of rods,i.e.,stress-free rods when straight versus when circular helices,Kirchhoff’s rod model versus Sadowsky’s ribbon model.Summing up,our findings highlight the key role of mutual interactions in generating a stable ensemble response that preserves the helical shape of the individual rods,as well as some interesting features,and they shed some light on the reasons why helical shapes in tubular assemblies are so common and persistent in nature and technology.
文摘Plant responses to drought are regulated by complex genetic and epigenetic networks leading to rapid reprogramming of plant growth, miRNAs have been widely indicated as key players in the regulation of growth and development. The role of miRNAs in drought response was investigated in young leaves of Brachypodium dis- tachyon, a drought-tolerant monocot model species. Adopting an in vivo drought assay, shown to cause a dramatic reduction in leaf size, mostly due to reduced cell expansion, small RNA libraries were produced from proliferating and expanding leaf cells. Next-generation sequencing data were analyzed using an in-house bioinformatics pipeline allowing the identification of 66 annotated miRNA genes and 122 new high confidence predictions greatly expand- ing the number of known Brachypodium miRNAs. In addition, we identified four TAS3 loci and a large number of siRNA-producing loci that show characteristics suggesting that they may represent young miRNA genes. Most miR- NAs showed a high expression level, consistent with their involvement in early leaf development and cell identity. Proliferating and expanding leaf cells respond differently to drought treatment and differential expression analyses suggest novel evidence for an miRNA regulatory network controlling cell division in both normal and stressed condi-tions and demonstrate that drought trigger a genetic reprogramming of leaf growth in which miRNAs are deeply involved.
基金supported by the China National Key Research and Development Project(No.2019YFB1312404)the Natural Science Foundation of China(No.51975401).
文摘The capsule robot(CR)is a promising endoscopic method in gastrointestinal diagnosis because of its low discomfort to users.Most CRs are used to acquire image information only and lack the ability to collect samples.Although some biopsy capsule robots(BCRs)have been developed,it remains challenging to acquire the intestinal tissue while avoiding tearing and adhesion due to the flexibility of colonic tissue.In this study,we develop a BCR with a novel sampling strategy in which soft tissue is scratched with sharp blades rotating at high speed to avoid tissue tearing.In the BCR design,a spiral spring with prestored energy is used to release high energy within a short period of time,which is dificult for a motor or magnet to perform within a small capacity installation space.The energy of the tightened spiral spring is transmitted to drive sharp blades to rotate quickly via a designed gear mechanism.To guarantee reliable sampling,a Bowden cable is used to transmit the user's manipulation to trigger the rotation of the blades,and the triggering force transmitted by the able can be monitored in real time by a force sensor installed at the manipulating end.A prototype of the proposed BCR is designed and fabricated,and its performance is tested through in vitro experiments.The results show that the proposed BCR is effective and the size of its acquired samples satisfies dinical requirements.
文摘We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes between the arms of the MZI, achieved by signal modulation on one of the arms of the interferometer together with pseudoheterodyne detection, and it allows us to avoid the use of costly equipment such as tunable light sources or spectrum analyzers. The obtained output signal is intrinsically independent of wavelength, power variations, and global thermal variations, making it extremely robust and adequate for use in real conditions. Using a silicon-on-insulator MZI, we demonstrate the real-time monitoring of refractive index variations and achieve a detection limit of 4.1 × 10^(-6)refractive index units(RIU).
基金supported by the National Natural Science Foundation of China(grant number 52375011)Shenzhen Science and Technology Program(grant number RCBS-20210609103901011)+1 种基金Shenzhen Peacock Innovation Team Project(grant number KQTD20210811090146075)State Key Laboratory of Mechanical System and Vibration(grant number MSV202306).
文摘Tens of crawling bio-robots with cockroaches as the mobile platform have been developed with various functions.Compared with artificial crawling robots of the same size,they revealed better flexibility,larger payload,and stronger endurance.These features made bio-robots ideal for pipeline inspection scenarios because the advancements in locomotion mechanisms and efficient power systems are still hurdles for current artificial systems.In this study,we controlled the bio-robot to crawl in the confined dark pipeline and achieved autonomous motion control with the help of an onboard sensing system.Specifically,a micro-camera was mounted on the electronic backpack of the cockroach for image collection,and an IMU sensor was used to compute its body orientation.The electronic backpack transmitted images to the host computer for junction recognition and distance estimation.Meanwhile,the insect's habituation to electrical stimulation has long been an uncertain factor in the control of bio-robots.Here,a synergistic stimulation strategy was proposed to markedly reduce the habituation and increase the number of effective turning controls to over 100 times.It is also found that both the increase of payload and the application of stimulations could promote the metabolic rate by monitoring carbon dioxide release.With the integration of synergistic stimulation and autonomous control,we demonstrated the fully autonomous pipeline navigation with our cockroach bio-robot,which realized the cycle number of approximately 10 in a roll.This research provides a novel technology that has the potential for practical applications in the future.
