The dynamics of genome size and GC contents evolution in genus Nicotiana

Hybridization and Polyploidization are most common of the phenomenon observed in plants, especially in the genus Nicotiana leading to the duplication of genome. Although genomic changes associated with these events has been studied at various levels but the genome size and GC content variation is less understood because of absence of sufficient genomic data. In this study the flow cytometry technique was used to uncover the genome size and GC contents of 46 Nicotiana species and we compared the genomic changes associated with the hybridization events along evolutionary time scale. The genome size among Nicotiana species varied between 3.28 pg and 11.88 pg whereas GC contents varied between 37.22% and 51.25%. The tetraploid species in genus Nicotiana including section Polydiclae, Repandae, Nicotiana, Rustica and Sauveolentes revealed both up and downsizing in their genome sizes when compared to the sum of genomes of their ancestral species. The genome sizes of three homoploid hybrids were found near their ancestral species. Loss of large genome sequence was observed in the evolutionary more aged species (>10 Myr) as compared to the recently evolved one’s (<0.2 Myr). The GC contents were found homogenous with a mean difference of 2.46% among the Nicotiana species. It is concluded that genome size change appeared in either direction whereas the GC contents were found more homogenous in genus Nicotiana.

A Novel Two-Axis Differential Resonant Accelerometer Based on Graphene with Transmission Beams

In this paper, a novel two-axis differential resonant accelerometer based on graphene with transmission beams is presented. This accelerometer can not only reduce the cross sensitivity, but also overcome the influence of gravity, realizing fast and accurate measurement of the direction and magnitude of acceleration on the horizontal plane. The simulation results show that the critical buckling acceleration is 460 g, the linear range is 0–89 g, while the differential sensitivity is 50,919 Hz/g, which is generally higher than that of the resonant accelerometer reported previously. Thus, the accelerometer belongs to the ultra-high sensitivity accelerometer. In addition, increasing the length and tension of graphene can obviously increase the critical linear acceleration and critical buckling acceleration with the decreasing sensitivity of the accelerometer. Additionally, the size change of the force transfer structure can significantly affect the detection performance. As the etching accuracy reaches the order of 100 nm, the critical buckling acceleration can reach up to 5 × 104 g, with a sensitivity of 250 Hz/g. To sum up, a feasible design of a biaxial graphene resonant accelerometer is proposed in this work, which provides a theoretical reference for the fabrication of a graphene accelerometer with high precision and stability.

The Research on Recrystallization Behaviors and Mechanism of a Medium-Density Ni-Based Alloy

Revealing the recrystallization behavior and mechanism of this new alloy is of great significance to subsequent research. In this study, the Ni-36.6W-15Co ternary medium heavy alloy was solution-treated at 1100–1200 °C for different lengths of time. The grain size change, microstructure and texture evolution as well as twin development during recrystallization annealing were analyzed using SEM, EBSD and TEM techniques. The study found that complete recrystallization occurs at 1150 °C/60 min. In addition, it takes a longer amount of time for complete recrystallization to occur at 1100 °C. The value of the activation energy Q1 of the studied alloys is 701 kJ/mol and the recrystallization process is relatively slow. By comparing the changes of microstructure and texture with superalloys, it is found that the recrystallization mechanism of the studied alloy is different from that of the superalloy. The development of annealing twins has a great influence on the recrystallization behavior and mechanism. The results show that the twin mechanism is considered as the dominant recrystallization mechanism of the studied alloy, although the formation and development of sub-grains appear in the early stage of recrystallization.

Visual Sequence Algorithm for Moving Object Tracking and Detection in Images

Objective. The effects of different algorithms on detecting and tracking moving objects in images based on computer vision technology are studied, and the best algorithm scheme is confirmed. Methods. An automatic moving target detection and tracking algorithm based on the improved frame difference method and mean-shift was proposed to test whether the improved algorithm has improved the detection and tracking effect of moving targets. The algorithm improves the traditional three-frame difference method and introduces a single Gaussian background model to participate in target detection. The improved frame difference method is used to detect the target, and the position window and center of the target are determined. Combined with the mean-shift algorithm, it is determined whether the template needs to be updated according to whether it exceeds the set threshold so that the algorithm can automatically track the moving target. Results. The position and size of the search window change as the target location and size change. The Bhattacharyya similarity measure ρ (y) exceeds the threshold r, and the target detection algorithm is successfully restarted. Conclusion. The algorithm for automatic detection and tracking of moving objects based on the improved frame difference method and mean-shift is fast and has high accuracy.

Eight-Year Outcomes of Implantation of Posterior Chamber Phakic Intraocular Lens With a Central Port for Moderate to High Ametropia

Purpose: To assess the 8-year clinical outcomes of implantation of an implantable collamer lens (ICL) with a central port (KS-Aquaport; EVO-ICL) for moderate to high myopia and myopic astigmatism.Methods: This retrospective study comprised a total of 177 eyes of 106 patients with spherical equivalents of −7.99 ± 3.33 D [mean ± standard deviation], who underwent EVO-ICL implantation. We evaluated the safety, efficacy, predictability, stability, and adverse events of the surgery, at 1 month, and 1, 2, 4, 6, and 8 years postoperatively.Results: The logarithm of the minimal angle of resolution (LogMAR) uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were −0.07 ± 0.17 and −0.20 ± 0.09, respectively, at 8 years postoperatively. The safety and efficacy indices were 1.18 ± 0.24 and 0.89 ± 0.28, respectively. At 8 years, 83 and 93% eyes were within ± 0.5 D and ± 1.0 D of the targeted correction, respectively. Change in manifest refraction from 1 month to 8 years postoperatively was −0.13 ± 0.30 D. Three eyes (1.7%) that developed cataracts had a slight pre-existing peripheral anterior subcapsular cataract formation required simultaneous ICL extraction and cataract surgery at 2 or 3 years or ICL size change (1 size up) at 7 years postoperatively. We found that neither significant intraocular pressure (IOP) rise (including pupillary block) nor significant endothelial cell loss occurred in any case throughout the 8-year observation period.Conclusions: Current ICL implantation with central port technology offered good continuous outcomes for all measures of safety, efficacy, predictability, and stability for correcting moderate to high myopic errors over a long period, thereby suggesting its long-term viability as a surgical approach for the treatment of such eyes.

Population genomic structure in Goodman's mouse lemur reveals long-standing separation of Madagascar's Central Highlands and eastern rainforests

Madagascar’s Central Highlands are largely composed of grasslands, interspersed with patches of forest. The pre-human extent of these grasslands is a topic of vigorous debate, with conventional wisdom holding that they are anthropogenic in nature and emerging evidence supporting that grasslands were a component of the pre-human Central Highlands vegetation. Here, we shed light on the temporal dynamics of Madagascar’s vegetative composition by conducting a population genomic investigation of Goodman’s mouse lemur (Microcebus lehilahytsara; Cheirogaleidae). These small-bodied primates occur both in Madagascar’s eastern rainforests and in the Central Highlands, which makes them a valuable indicator species. Population divergences among forest-dwelling mammals can serve as a proxy for habitat fragmentation and patterns of post-divergence gene flow can reveal potential migration corridors consistent with a wooded grassland mosiac. We used RADseq data to infer phylogenetic relationships, population structure, demographic models of post-divergence gene flow, and population size change through time. These analyses offer evidence that open habitats are an ancient component of the Central Highlands, and that wide-spread forest fragmentation occurred naturally during a period of decreased precipitation near the last glacial maximum. Models of gene flow suggest that migration across the Central Highlands has been possible from the Pleistocene through the recent Holocene via riparian corridors. Notably, though our findings support the hypothesis that Central Highland grasslands predate human arrival, we also find evidence for human-mediated population declines. This highlights the extent to which species imminently threatened by human-mediated deforestation may be more vulnerable from paleoclimatic changes.

637 Real-world experience with the new watchman FLX device: data from two high volume sicilian centres. The FLX-iest registry

Aims Left Atrial Appendage closure (LAAC) represents a standard therapy for patients with Atrial Fibrillation and contraindication to oral anticoagulation (OAC). The ‘Watchman FLX’ presented innovative features: higher conformability to LAA shapes, reduced length of the device, closed ‘atraumatic’ distal end with ‘flex-ball’ shape during deployment, flattened covered external surface. We report the early ‘real-world’ experience with the innovative Watchman-FLX device, in two centres at high-procedural volume with consolidated LAAC experience. Methods and results From May 2019 to January 2021, we enrolled 200 consecutive patients treated with Watchman FLX in a non-randomized double-centre registry. We collected procedural data and followed up the patients for mid-term clinical outcomes. Mean age was 77 ± 7.18 years (67.5% male). Patients presented hypertension in 93% of cases, CKD in 57.5% (mean creatinine level 2 ± 1.1), Diabetes mellitus in 41.5%, Coronary artery disease and Heart failure in 55%. 29% had previous stroke and 56.5 bleeding events. Mean CHA2DS2-VASc was 5 ± 1.40 and HAS-BLED 4 ± 1.01. LAAC indication was: 39.5% of cases symptomatic Haemorrhage, 39% need for Triple antithrombotic therapy, 32% gastro-intestinal bleeding; 18% of patients presented OAC intolerance. TEE guidance was feasible in 186 cases (93%), of which 96 (48%) in general anesthesia and 90 (45%) in conscious sedation (MID-DEX) protocol. 14 ICE cases (7%) were performed in local anesthesia. FLX device repositioning after first attempt was required in 40 cases (20%) without any complication. Device size change, after first choice was needed in eight cases (4%). In one exceptional case simultaneous implant of two Watchman FLX devices was performed in a bi-lobed LAA. Peri-device leak was found in two cases (1%), one solved by changing FLX size (31 to 35 mm). Final procedural success was 99.5%; one unsuccessful case due to LAA reverse chicken-wing with very short depth; no device embolization. Six complications were related to access-site (3%), two cases of combined LAAC-Mitraclip procedure; two major bleedings occurred and one in-hospital death due to hemorrhagic shock (HAS-BLED = 6). At mean follow-up of 272 ± 172.76 days, only 2% of (non-device-related) stroke and 0.6% fatal bleeding resulted. Conclusions Our registry in a high-risk population treated with the innovative Watchman FLX device, showed high technical procedural success with easy implant and repositioning, no embolization, good LAA sealing and low rate of ischaemic/bleeding complications. 637 Figure