Initial Opening Research Articles

High precision FRET studies reveal reversible transitions in nucleosomes between microseconds and minutes

Nucleosomes play a dual role in compacting the genome and regulating the access to DNA. To unravel the underlying mechanism, we study fluorescently labeled mononucleosomes by multi-parameter FRET measurements and characterize their structural and dynamic heterogeneity upon NaCl-induced destabilization. Species-selective fluorescence lifetime analysis and dynamic photon distribution analysis reveal intermediates during nucleosome opening and lead to a coherent structural and kinetic model. In dynamic octasomes and hexasomes the interface between the H2A-H2B dimers and the (H3-H4)2 tetramer opens asymmetrically by an angle of ≈20° on a 50 and 15 µs time scale, respectively. This is followed by a slower stepwise release of the dimers coupled with DNA unwrapping. A mutation (H2A-R81A) at the interface between H2A and H3 facilitates initial opening, confirming the central role of the dimer:tetramer interface for nucleosome stability. Partially opened states such as those described here might serve as convenient nucleation sites for DNA-recognizing proteins.

Clinical effectiveness evaluation of laser therapy and dry needling in treatment of patients with myofascial pain in masseter muscle

Myofascial pain is considered a type of muscular TMD, being common in patients with musculoskeletal pain associated with active or latent trigger points. Among the therapeutic options, there are low-intensity laser therapy and dry needling. The aim of this study was to compare the efficacy of these two therapies in the masseter muscles of patients with myofascial pain. Ten patients diagnosed with myofascial pain, with or without limitation of mouth opening, were randomly divided into two groups for treatment with low intensity laser therapy (G1) (n = 5) or dry needling (G2) (n = 5). The pain symptomatology and the mouth opening measurement were evaluated weekly before the start of treatment, and one week after the final treatment. The comparison between G1 and G2 in relation to the improvement in mouth opening was not statistically significant (p> 0.05). However, dry needling (G2) has shown numerically to be more effective than laser therapy in a shorter period comparing initial and final mouth opening. Regarding the pain symptomatology, both therapies were effective comparing the initial and final evaluations of patients with myofascial pain (p <0.05).

Formation of bedding-parallel, fibrous calcite veins in laminated source rocks of the Eocene Dongying Depression: A growth model based on petrographic observations

Bedding-parallel, fibrous calcite veins (commonly referred to as “beefs”) are widely developed within Eocene, lacustrine, laminated organic-rich source rocks in the Dongying Depression of Bohai Bay Basin, East China. Understanding the formation of this type vein is essential to elucidate the diagenetic evolution and fluid migration in muddy source rocks. This study investigates the mechanism(s) of growth of bedding-parallel veins in hydrocarbon source rocks of the Es4 upper and the Es3 lower units in the Dongying Depression, based on systematic observations of macro- and micro-scale features both in veins and their wall-rocks, combined with X-ray diffraction and analyses of geochemical indicators.The source rocks are heterogeneous in both composition and structure. The beefs mainly occur in laminated rocks consisting of organic-rich laminae, which occur together with horizontally-continuous banded lamalginites and rare carbonate-rich laminae, overall corresponding to high TOC, low carbonate contents, and low maturity (average Ro = 0.57%). Most beefs are embedded in the neighboring lamalginites of organic-rich laminae with low clay-mineral contents. The beefs are products of diagenesis accompanying burial, and both the initial fracture opening and subsequent dilation represent early stages of hydrocarbon generation and expulsion. The presence of bedding-parallel bituminite veins and the median plane (or “parting”) is evidence for horizontally oriented hydrofracturing due to fluid overpressure. In turn, fluid overpressure reflects the generation and primary migration of hydrocarbon-bearing fluids. Hydrocarbon generation (organic matter evolution) and clay-mineral dehydration (illitization of smectite) were responsible for the fluid overpressure. Crystal growth within the beefs was a continuous process with an antitaxial growth direction, and there was no growth competition between adjacent fibres. These observations indicate that the crystal growth and fracture dilation were synchronous and growth space was limited. The force exerted by crystallizing vein fill contributed to the high fluid pressure, suggesting that fibrous vein minerals actively promoted further dilation as the veins grew. Vein dilation accompanied the migration of hydrocarbon-bearing fluids, evinced by the occurrence of primary hydrocarbon inclusions found in the fibrous calcites. Therefore, the hydrocarbon-bearing fluids were present at the time of horizontal fluid flow, from the start of fracture opening to the end of the dilation.

Genetic divergence of aromatic rice (Oryza sativa L.)

Thirty aromatic rice genotypes were studied to assess the nature and magnitude of genetic divergence among them for grain yield and yield contributing characters. Based on 23 characters the genotypes were grouped into 5 clusters. Inter-distances were higher than intra-cluster showing a wide range of genetic diversity among the genotypes of different groups. The highest level of inter-cluster distance (73.48) was found between cluster IV and V. The highest intra-cluster distance (3.364) was computed to cluster V and the lowest 1.851 was observed in cluster IV. Panicle length, days to initial flower opening, spikelet sterility, pollen fertility and harvest index had maximum contribution towards genetic divergence of 30 aromatic rice genotypes. Genotypes having these characters in the genetically distant cluster could, therefore, offer a significant scope for the development of high yielding variety through judicious selection.

Biophysical Mechanisms of Membrane-Thickness-Dependent MscL Gating: An All-Atom Molecular Dynamics Study.

The bacterial mechanosensitive channel, MscL, is activated by membrane tension, acting as a safety valve to prevent cell lysis against hypotonic challenge. It has been established that its activation threshold decreases with membrane thickness, while the underlying mechanism remains to be solved. We performed all-atom molecular dynamics (MD) simulations for the initial opening process of MscL embedded in four different types of lipid bilayers with different thicknesses: 1,2-dilauroyl- sn-glycero-3-phosphocholine (DLPC)), 1,2-dimyristoyl-glycero-3-phosphorylcholine (DMPC), 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), and 1,2-distearoyl- sn-glycero-3-phosphocholine (DSPC). In response to membrane stretching, channel opening occurred only in the thinner membranes (DLPC and DMPC) in a thickness-dependent way. We found that the MscL opening was governed by the rate and degree of membrane thinning and that the channel opening was tightly associated with the tilting of transmembrane (TM) helices of MscL toward the membrane plane. Upon membrane stretching, the order parameter of acyl chains of thinner membranes (DLPC and DMPC) became smaller, whereas other thicker membranes (DPPC and DSPC) showed interdigitation with little changes in the order parameter. The decreased order parameter contributed much more to membrane thinning than did interdigitation. We conclude that the membrane-thickness-dependent MscL opening mainly arises from structural changes in MscL to match the altered membrane thickness by stretching.

Public Sector Innovation as Governance Reform: A Comparative Analysis of Competitive and Collaborative Strategies in the Swedish Transport Sector

The constraining impact of bureaucracy on creative problem solving has been a recurring theme in research on public innovation, and public actors increasingly seek to “steer” innovation through interactive spaces for collaboration and competition. This article examines this form of “meta-governance” in the case of the Swedish Transport Administration and reveals a pattern where the initial opening of arenas for innovation is followed by a countermovement toward organization. Findings suggest that the introduction of elements of organization, such as hierarchy, rules, and membership, in governance spaces is a key strategy for coming to grips with a new innovation promoting role.

Cryptococcal Meningitis: A Retrospective Cohort of a Brazilian Reference Hospital in the Post-HAART Era of Universal Access.

Objective Cryptococcus neoformans is a common opportunistic infection in adults with acquired immunodeficiency syndrome worldwide. However, limited data exist for HIV-infected patients in the post-HAART (highly active antiretroviral therapy) era in Brazil. The aim of this study was to describe the clinical characteristics and outcomes of cryptococcosis in a cohort of patients attending a teaching tertiary care hospital in southern Brazil after the introduction of HAART in Brazil. Patients and Methods A retrospective study was conducted in tertiary care hospital in southern Brazil. Detailed data on risk factors, clinical manifestations, diagnosis methods, treatment, and prognosis of patients with meningeal cryptococcosis were evaluated from January 2009 to December 2016. Results Seventy-nine cases of cryptococcal meningitis were identified. Most of the patients presented positive CSF (cerebrospinal fluid) cultures for Cryptococcus neoformans (96%). The prevalence of males and females with meningeal cryptococcosis was similar. The age of the patients ranged from 5 to 67 years. The median time of hospitalization was 28 days. The most common underlying disease was HIV (82%), followed by solid transplant (10%). Fever, nausea, vomiting, headache, and altered mental status were the most common clinical manifestations. Initial opening intracranial pressures varied from 30 to 130 cm H2O. CNS imaging abnormalities include hydrocephalus and hypodensities. Widened Virchow–Robin spaces were described in only 2 patients (2.5%). Induction treatment of the majority of the patients consisted of amphotericin B and flucytosine (67%) followed by amphotericin B and fluconazole (19%). Multivariate analysis of Cox regression identified headache at presentation, mechanical ventilation, CSF glucose <20 mg/dL, and CSF cryptococcal antigen ≥1 : 1000 for independent risk factors for death. All-cause 30-day and 60-day mortalities were 19% and 24%, respectively. Conclusions Meningeal cryptococcosis mostly caused by C. neoformans continues to occur predominantly in HIV-infected adults despite HAART being widely distributed in Brazil. Cryptococcosis remains a significant opportunistic infection in solid organ transplant recipients. Despite adequate antifungal treatment and management of intracranial hypertension in a reference tertiary care hospital, mortality was high. Identification of risk factors and additional treatment modalities, especially for intracranial hypertension, are necessary to improve care for patients with cryptococcal meningitis.

Formation of the initial kidney and mouth opening in larval amphioxus studied with serial blockface scanning electron microscopy (SBSEM)

BackgroundFor early larvae of amphioxus, Kaji et al. (Zool Lett 2:2, 2016) proposed that mesoderm cells are added to the rim of the forming mouth, giving it the quality of a coelomoduct without homology to the oral openings of other animals. They depended in part on non-serial transmission electron microscopic (TEM) sections and could not readily put fine structural details into a broader context. The present study of amphioxus larvae is based largely on serial blockface scanning electron microscopy (SBSEM), a technique revealing TEM-level details within an extensive anatomical volume that can be reconstructed in three dimensions.ResultsIn amphioxus larvae shortly before mouth formation, a population of compact mesoderm cells is present at the posterior extremity of the first left somite. As development continues, the more dorsal of these cells give rise to the initial kidney (Hatschek’s nephridium), while the more ventral cells become interposed between the ectoderm and endoderm in a localized region where the mouth will soon penetrate. SBSEM reveals that, after the mouth has opened, a majority of these mesoderm cells can still be detected, sandwiched between the ectoderm and endoderm; they are probably myoblasts destined to develop into the perioral muscles.ConclusionsSBSEM has provided the most accurate and detailed description to date of the tissues at the anterior end of amphioxus larvae. The present study supports the finding of Kaji et al. (2016) that the more dorsal of the cells in the posterior region of the first left somite give rise to the initial kidney. In contrast, the fate of the more ventral cells (called here the oral mesoderm) is less well understood. Although Kaji et al. (2016) implied that all of the oral mesoderm cells joined the rim of the forming mouth, SBSEM reveals that many of them are still present after mouth penetration. Even so, some of those cells go missing during mouth penetration and their fate is unknown. It cannot be ruled out that they were incorporated into the rim of the nascent mouth as proposed by Kaji et al. (2016). On the other hand, they might have degenerated or been shed from the larva during the morphogenetic interaction between the ectoderm and endoderm to form the mouth. The present SBSEM study, like Kaji et al. (2016), is based on static morphological data, and dynamic cell tracer experiments would be needed to decide among these possibilities.

Extent, thickness and erosion of the Jurassic continental flood basalts of Dronning Maud Land, East Antarctica: A low-T thermochronological approach

The Dronning Maud Land Mountains form a c. 1500 km long, coast-parallel escarpment that possibly formed by flexural uplift during Jurassic rifting between East and West Gondwana. Contemporaneous to the rifting, considerable amounts of continental flood basalts, associated with the Karoo mantle plume, were emplaced at c. 183 Ma. The basalts are still widespread in South Africa, making up elevated topography, but are only preserved as smaller remnants in western Dronning Maud Land. By investigating the paleo-thermal effect of the basalts, we aim to constrain the extent and original thickness, as well as the subsequent erosion history of the Jurassic continental flood basalts. Thus, we have applied low-temperature thermochronological methods to 40 samples from western Dronning Maud Land. This has resulted in 34 new apatite fission track ages, ranging from c. 310 to 90 Ma, 31 apatite (U–Th)/He ages spanning from c. 400 to 50 Ma and, and 9 zircon (U–Th)/He ages between c. 650 and 200 Ma.Thermal modelling of 26 samples indicates variable thickness of the Jurassic basaltic cover. The greatest basaltic thicknesses are recorded in Heimefrontfjella and H.U. Sverdrupfjella, where up to c. 2 km are estimated. Thicknesses at Kirwanveggen, Hochlinfjellet, Midbresrabben and Ahlmannryggen range from c. 100 m to 600 m. Thickness variations are attributed to the proximity to the emplacement zone, possible pre-existing topography and syn-volcanic rift flank uplift.Since the continental flood basalt emplacement, two phases of enhanced cooling have been documented: 1) A Jurassic-Cretaceous cooling phase is attributed to reactivation of the Jutulstraumen–Penckgraben rift, the initial rifting and opening of the South Atlantic and enhanced chemical weathering and deep erosion due to a Jurassic temperate–subtropical climate. 2) Late Paleogene cooling is attributed to the transition from green house to ice-house conditions and ice-sheet initiation at the Eocene-Oligocene boundary. Post-Jurassic denudation of at least 2 km in some places is suggested.

Analytical solution of energy redistribution in rectangular openings upon in-situ rock mass alteration

This paper aims at deriving analytical expressions of mining-induced energy redistribution around rectangular openings that involve local alteration of rock mass properties. As energy combines the effects of strains and stresses simultaneously, this research work is intended to complement existing approaches that rely on stress-based stability criteria. The energy density on the boundaries and its distribution within the domain, obtained analytically through direct derivation, is compared to numerical solutions obtained by Finite Element simulation for a given hypothetical field case. The analytical and numerical solutions show a good agreement and reflect the importance of analytical solutions especially in the vicinity of severe geometrical singularities. Our parametric study shows that the initial stress coefficient and opening span-height ratio have great influence on the variation of strain energy density. We found that the energy density concentrates on the excavation corners and that the energy density concentration index value on the opening side boundary decreases when the span-height ratio decreases. Areas of energy reduction appear on the excavation boundaries, which transform from the top centers to the side centers as the initial stress coefficient increases. Our study indicates that both energy density concentration and reduction areas need to be considered in excavation design. The derived expressions of mining-induced energy redistribution can be considered as a tool to assess the stability of rock masses and predict failure conditions such as rock burst and mine seismicity around non-circular shaped openings.

Thinking from the Yamanote: space, place and mobility in Tokyo's past and present

Tokyo's Yamanote train line has been at the centre of Japan's modernisation project and continues to define socio-spatial relations within the city today. Within this special issue of Japan Forum, we trace the contours of the Yamanote line, exploring its role as a form of mobility that creates temporalities, spaces and boundaries, and the modes of intimacy and estrangement such dynamics produce. The papers within this special issue were developed out of discussions held at the Chicago AAS conference 2015. That year marked the 130th anniversary of the line's initial opening and the ninetieth anniversary of the completion of the loop. A focus on the Yamanote line provided us with fruitful reflections on migration and marginalisation, the way space is imagined and represented in the city, and how everyday life is both disciplined and disrupted. These reflections are included throughout the contributions within this special issue as they relate to Japan; however, they also attest to the continued importance of Japan as a site to reflect on broader socio-historical questions. As we show in this special issue, thinking from the Yamanote line not only allows us to think about Tokyo or Japan, but also affords attention to wider questions relevant to urban life more generally.

Design and experiment of automatic transplanting device for potted tomato seedlings

In this study, an automatic machine for transplanting potted tomato seedlings was designed, based on the analysis of physical characteristics of the main varieties of tomato seedlings. The machine is composed of a horizontal and vertical seedling supply mechanism, a picking mechanism composed with a gear-rod component, a planting part featured with an eccentric-disk parallelogram duckbilled mechanism, and a control system. The control system included position sensors, stepper motor, variable-frequency motor and program controller. The force condition for successful picking potted tomato seedlings was studied by analyzing the force and motion during the taking procedure with the use of analytical graphic method. Combined with the parameters of physical characteristics of tomato seedlings, the key parameters of the machine was determined, which included L1 = 105 mm as the distance between the point of the gripper needles and the center of rotation, L0 = 18 mm as the initial opening distance between the two gripper needles, and s = 40 mm as the distance between the two gripper needles when they were at the upper hinge point of the clamping hands. The key structure and the parameters of the seedlings-taking part were determined by theoretical calculation according to the position of the seedling during taking and dropping procedure, and the requirement of the motion. The machine was tested by using the potted tomato seedlings. The result showed that the seedling picking rate was 92.35%–86.61%, and the leakage rate was 12.57%–18.03%, when the transplanting speed was between 60 and 90 seedlings per minute. The result demonstrated that the machine was feasible to transplant the potted tomato seedlings efficiently.

Postglacial vegetation and climate history and traces of early human impact and agriculture in the present-day cool mixed forest zone of European Russia

This study is based on the reassessment and correlation of five pollen records from the upper Western Dvina River region. For the most complete record (Korovinskoe Mire; 56°16′N, 31°20′E) we constructed a Bayesian age-depth model to provide robust chronological control for the reconstructed changes in the regional environments and to facilitate interregional comparisons. The results show that the Holocene Thermal Maximum in the study region (ca. 8600–6900 cal BP) started and ended some centuries earlier than suggested for the neighboring Baltic region (ca. 8100–5600 cal BP). The spruce (Picea) pollen records corroborate other palaeobotanical records from the wider region indicating a relatively dry early and middle Holocene and cooler/wetter conditions after ca. 5400 cal BP. Local initial opening of forests by Neolithic populations is indicated by 7600 cal BP and a stepwise intensification of forest clearance is registered from ca. 4200/3700 and ca. 1400–1000 cal BP. There is evidence for an asynchronous pattern of human impact during the early period of occupation prior to ca. 4000 cal BP, which can be explained by a low density and uneven distribution of prehistoric hunter-fisher-gatherer populations. Although single Cerealia-type pollen grains are registered as early as ca. 6700 cal BP, intensive cultivation of cereals in the study region probably did not occur before ca. 1400 cal BP, i.e. much later than suggested for the Baltic states, Poland, and Belarus.

Sedimentary characteristics and provenance of the basal conglomerate of the Late Jurassic-Early Cretaceous Jiaolai Basin, eastern China and their implications for the uplift of the Sulu Orogenic Belt

ABSTRACTThe basal conglomerates (‘Linsishan Conglomerate’, LC, herein) are exposed discontinuously along the northern part of the Sulu Orogenic Belt (SOB) and the southern part of the Jiaobei Terrane. Studying these conglomerates can offer key constrains for the formation age of the Jiaolai Basin and improve our understanding of the uplift and erosional histories of the SOB and Jiaobei Terrane, which are still in great controversy. In Huangyadi section, the LC is characterized as debris-flow deposits, channel deposits, and sheet-flow deposits. However, in Shanjiao section, the LC is changed to sheet-flow and sieve deposits, as well as debris-flow and channel deposits. These deposit characteristics indicate an unstable tectonic setting during initial opening stage of the basin. Based on the data of conglomerate component, palaeocurrent, and debris zircons ages, it can be inferred that the sediments in the Laiyang region were sourced from the Jiaobei Terrane and Northern Sulu Orogenic Belt (NSOB), and the sediments in the Zhucheng and Wulian regions were derived from the Jiaobei Terrane and the Southern Sulu Orogenic Belt (SSOB). Besides, the sediments in the Haiyang and Jimo regions were provided by the NSOB and SSOB, respectively. The significant SHRIMP U–Pb ages of a tuff developing in the LC has been obtained, indicating that 149 ± 2.5 Ma is the oldest age constraint for the Jiaolai Basin. In addition, our result shows that the Latest Jurassic (ca. 149 Ma) may be a critical time; before this time, the Jiaobei Terrane and the SOB experienced a rapid uplift with minimal uplift velocity (~0.9 km/Ma); since then, the Orogen began to collapse and a series of basins formed rapidly in its core, which indicate the tectonic stress regime of the Dabie-Sulu Orogen varied from compressional stress to tensile stress.

Humidity- and light-driven actuators based on carbon nanotube-coated paper and polymer composite.

Multi-responsive actuators driven by different stimuli (e.g. light, humidity, electricity) have attracted intense attention recently for the advantages of being used in various environments and show enormous actuation. In this work, we propose humidity- and light-driven actuators based on carbon nanotube (CNT)-coated paper and a biaxially oriented polypropylene (BOPP) composite. The CNT-paper/BOPP actuator shows large bending actuation when driven by humidity change (curvature of 1.2 cm-1) and near infrared (NIR) light irradiation (curvature up to 1.6 cm-1). The great actuation performances outperform most other paper-based actuators. Finally, a smart gripper, of which the initial opening width can be enlarged, is fabricated on the basis of the CNT-paper/BOPP actuators. By utilizing the bidirectional bending motion of the actuator, the opening width of the gripper can increase to a width that is 4 times larger than its initial width, so as to grasp a large object. The gripper is also able to raise and move an object that is 20 times heavier than one actuator of the gripper. We assume that this new type of actuator has great potential in artificial muscle, soft robotics and biomimetic applications.

Anterior capsulorhexis opening reduction after cataract surgery with subluxated lenses

Background and objectiveThis study sought to evaluate anterior capsulorhexis opening (ACO) reductions after surgery for a subluxated lens. Significant reduction of an ACO supports direct zonular involvement (capsular factors excluded by use of capsular tension rings [CTRs] and modern intraocular lens [IOLs]), and these findings question the long-term efficacy of subluxated lens surgery by means of cataract surgery. A small ACO due to lens mobility, non-enlargement of the ACO, and no lens epithelial cell washing due to an additional risk of further zonular damage were left as additional features to evaluate the possible outcomes of this simplified but still complicated surgery. Materials and methodsData from 30 patients were used in the final analysis of this prospective study. Phacoemulsifications of subluxated lenses were performed in all patients, and iris/capsule hooks and CTRs or Cionni rings were used as stabilisers of the lens. Photography of the anterior parts (performed at 1 day, 1 week, 1 month, 3 months and 6 months after surgery) was used to evaluate the anterior capsulorhexis openings. ResultsSmall initial anterior capsulorhexis openings (13.54mm2) were achieved, and the area reduction at 6 months was 16.70% (mean area at month 6: 11.28mm2, P<0.001). The reduction of the ACO area in the pseudoexfoliation (PEX) syndrome patients was 20% relative to the initial size (13.49mm2 vs. 10.92mm2, P<0.001). Two patients exhibited marked ACO reductions, and both were referred for anterior laser capsulotomy treatment. ConclusionsA weak or partially absent zonule does not markedly affect the reduction of the anterior capsule opening if appropriate surgical techniques, support materials and IOLs are used, even in the presence of a small initial capsulorhexis opening area. Therefore, a cataract surgery approach on the subluxated lens should be used. Ocular comorbidities, particularly PEX syndrome, play more significant roles in ACO reduction, and appropriate ACO size reducing inhibitors (e.g., anterior laser capsulotomy) or other types of surgery should be used.

TFIIH generates a six-base-pair open complex during RNAP II transcription initiation and start-site scanning

Eukaryotic mRNA transcription initiation is directed by the formation of the megaDalton-sized pre-initiation complex (PIC). After PIC formation, double-stranded DNA is unwound to form a single-stranded DNA bubble and the template strand is loaded into the polymerase active site. DNA opening is catalyzed by Ssl2(XPB), the dsDNA translocase subunit of the basal transcription factor TFIIH. In yeast, transcription initiation proceeds through a scanning phase where downstream DNA is searched for optimal start-sites. Here, to test models for initial DNA opening and start-site scanning, we measure the DNA bubble sizes generated by Saccharomyces cerevisiae PICs in real time using single-molecule magnetic tweezers. We show that ATP hydrolysis by Ssl2 opens a 6 base-pair (bp) bubble that grows to 13 bp in the presence of NTPs. These observations support a two-step model wherein ATP-dependent Ssl2 translocation leads to a 6 bp open complex which RNA polymerase II expands via NTP-dependent RNA transcription.

Functional relationship of AtABCG21 and AtABCG22 in stomatal regulation

Stomatal regulation is important for water transpiration from plants. Stomatal opening and closing are controlled by many transporter proteins in guard cells. AtABCG22 is a member of the ATP-binding cassette (ABC) transporters and is a stomatal regulator; however, the function of AtABCG22 has not yet been determined fully, although a mutant phenotype included a significant effect on stomatal status. Here, we further investigated the function of the AtABCG22 gene and its functional relationships with other subfamily genes. Among close family members, we found a functional relationship of stomatal phenotypes with AtABCG21, which is also expressed specifically in guard cells. Based on an analysis of double mutants, adding the atabcg21 mutation to atabcg22 mutant partially suppressed the open-stomata phenotype of atabcg22. Multiple-mutant analyses indicated that this suppression was independent of abscisic acid signaling in guard cells. We also found that atabcg22 mutant showed a unique time course-dependent phenotype, being defective in maintenance of stomatal status after initial stomatal opening elicited by light signaling. The function of AtABCG22 and its relationship with AtABCG21 in stomatal regulation are considered.

An improved approximation algorithm for the k-level facility location problem with soft capacities

We consider the k-level facility location problem with soft capacities (k-LFLPSC). In the k-LFLPSC, each facility i has a soft capacity u i along with an initial opening cost f i ≥ 0, i.e., the capacity of facility i is an integer multiple of u i incurring a cost equals to the corresponding multiple of f i . We firstly propose a new bifactor (ln(1/β)/(1 −β),1+2/(1 −β))-approximation algorithm for the k-level facility location problem (k-LFLP), where β ∈ (0, 1) is a fixed constant. Then, we give a reduction from the k-LFLPSC to the k-LFLP. The reduction together with the above bifactor approximation algorithm for the k-LFLP imply a 5.5053-approximation algorithm for the k-LFLPSC which improves the previous 6-approximation.

A Prestressed Soft Gripper: Design, Modeling, Fabrication, and Tests for Food Handling

This study presented a prestressed soft gripper fabricated with 3-D printing technology. The gripper can realize a large contact area while grasping and simultaneously generate large initial opening without deflating the soft actuators. The soft actuator was 3-D printed as two separate parts: the soft chambers with a rigid connector and a cover to seal the chambers. The chamber part was stretched longitudinally and sealed by gluing the cover onto it. The actuator was then released, and an initial curl occurred due to the remaining prestress. Finite element (FE) simulations were performed to validate this concept and the designed structure. Actuator fabrication and experimental tests were presented, and agreements between the FE simulations and test results were achieved. A gripper consisting of four prestressed actuators was constructed and experimentally tested by picking-and-placing food materials in different weights and different sized containers. To adapt to objects of different sizes and shapes, the gripper base was designed to have two configurations and two openings. The results showed that the prestressed gripper could stably handle various types of food and still remain compact with a simple supporting system.