Efficient and durable uranium extraction from uranium mine tailings seepage water via a photoelectrochemical method

Current photocatalytic uranium (U) extraction methods have intrinsic obstacles, such as the recombination of charge carriers, and the deactivation of catalysts by extracted U. Here we show that, by applying a bias potential on the photocatalyst, the photoelectrochemical (PEC) method can address these limitations. We demonstrate that, owing to efficient spatial charge-carriers separation driven by the applied bias, the PEC method enables efficient and durable U extraction. The effects of multiple operation conditions are investigated. The U extraction proceeds via single-step one-electron reduction, resulting in the formation of pentavalent U, which can facilitate future studies on this often-overlooked U species. In real seepage water the PEC method achieves an extraction capacity of 0.67 gU m(-3).h(-1) without deactivation for 156 h continuous operation, which is 17 times faster than the photocatalytic method. This work provides an alternative tool for U resource recovery and facilitates future studies on U(V) chemistry

Realization of multiple charge density waves in NbTe2 at the monolayer limit

Abstract: Layered transition-metal dichalcogenides (TMDCs) down to the monolayer (ML) limit provide a fertile platform for exploring charge-density waves (CDWs). Though bulk NbTe2 is known to harbor a single axis 3*1 CDW coexisting with non-trivial quantum properties, the scenario in the ML limit is still experimentally unknown. In this study, we unveil the richness of the CDW phases in ML NbTe2, where not only the theoretically predicted 4*4 and 4*1 phases, but also two unexpected sqrt(28)*sqrt(28) and sqrt(19)*sqrt(19) phases, can be realized. For such a complex CDW system, we establish an exhaustive growth phase diagram via systematic efforts in the material synthesis and scanning tunneling microscope characterization. Moreover, we report that the energetically stable phase is the larger scale order (sqrt(19)*sqrt(19)), which is surprisingly in contradiction to the prior prediction (4*4). These findings are confirmed using two different kinetic pathways, i.e., direct growth at proper growth temperatures (T), and low-T growth followed by high-T annealing. Our results provide a comprehensive diagram of the "zoo" of CDW orders in ML 1T-NbTe2 for the first time and offer a new material platform for studying novel quantum phases in the 2D limit

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Modeling and Control of a Wheeled Biped Robot

It is difficult to realize the stable control of a wheeled biped robot (WBR), as it is an underactuated nonlinear system. To improve the balance and dynamic locomotion capabilities of a WBR, a decoupled control framework is proposed. First, the WBR is decoupled into a variable-length wheeled inverted pendulum and a five-link multi-rigid body system. Then, for the above two simplified models, a time-varying linear quadratic regulator and a model predictive controller are designed, respectively. In addition, in order to improve the accuracy of the feedback information of the robot, the Kalman filter is used to optimally estimate the system state. The control framework can enable the WBR to realize changing height, resisting external disturbances, velocity tracking and jumping. The results obtained by simulations and physical experiments verify the effectiveness of the framework

Impact of a Combined High Cholesterol Diet and High Glucose Environment on Vasculature

<div><p>Aims</p><p>Vascular complications are the leading cause of mortality and morbidity in patients with diabetes. However, proper animal models of diabetic vasculopathy that recapitulate the accelerated progression of vascular lesions in human are unavailable. In the present study, we developed a zebrafish model of diabetic vascular complications and the methodology for quantifying vascular lesion formation real-time in the living diabetic zebrafish.</p><p>Methods and Results</p><p>Wild type zebrafish (AB) and transgenic zebrafish lines of <i>fli1:EGFP</i>, <i>lyz:EGFP, gata1:dsRed</i>, double transgenic zebrafish of <i>gata1:dsRed/fli1:EGFP</i> were exposed to high cholesterol diet and 3% glucose (HCD-HG) for 10 days. The zebrafish model with HCD-HG treatment was characterized by significantly increased tissue levels of insulin, glucagon, glucose, total triglyceride and cholesterol. Confocal microscopic analysis further revealed that the diabetic larvae developed clearly thickened endothelial layers, distinct perivascular lipid depositions, substantial accumulations of inflammatory cells in the injured vasculature, and a decreased velocity of blood flow. Moreover, the vascular abnormalities were improved by the treatment of pioglitazone and metformin.</p><p>Conclusion</p><p>A combination of high cholesterol diet and high glucose exposure induces a rapid onset of vascular complications in zebrafish similar to the early atherosclerotic vascular injuries in mammalian diabetic models, suggesting that zebrafish may be used as a novel animal model for diabetic vasculopathy.</p></div

Endothelial layer thickening of optical vessels in HCD-HG treatment group.

<p>A: Different treatments led to changes of endothelial layer in optical arteries. Transgenic zebrafish (Fli1:EGFP) larvae were imaged in a lateral position by confocal microscope, and emission wavelength of 488 nm was detected. Scale bar  = 10 µm. B: Endothelial layer thickness (T) was measured by subtracting inner diameter (Di) from outer diameter (Do), T = (Do-Di)/2. Changes in the thickness of endothelial layer were quantified and presented as mean ±SD. Scale bar  = 20 µm. C: Pioglitazone and metformin effectively prevented the endothelial layer from becoming thick afer HCD-HG treatment. N = 11 in the control group, N = 24 in the HCD-HG group, N = 10 in HCD-HG+ pioglitazone group, N = 18 in HCD-HG+ metformin group. PGZ: pioglitazone; Met: metformin. Asterisk (*): Comparison of EC layer thickness between control group and HCD-HG group (p<0.05). Cross (†): Comparison of EC layer thickness between control and drugs treatment groups (p<0.05).</p

HCD-HG treatment induced inflammatory cells infiltration.

<p>A: HCD-HG treatment resulted in the increased number of GFP⁺ cells around the caudal vein. B: GFP⁺ cells that locate within 50 µm from the lumen of the caudal artery were counted. n>5 in each group and the experiment was repeated for three times. The results were compared between normal and HCD-HG treated group, HCD-HG treated group and HCD-HG+ pioglitazone or metformin group respectively compared between the four groups by Student t test, p<0.05. Scale bar  = 80 µm. Asterisk (*): Comparison of the number of GFP⁺ cells between control group and HCD-HG group. Cross(†): Comparison of the number of GFP⁺ cells between HCD-HG group and drug treatment groups, respectively.</p

Characterizing Spatial Patterns of Pine Wood Nematode Outbreaks in Subtropical Zone in China

Pine wood nematode (PWN), Bursaphelenchus xyophilus, originating from North America, has caused great ecological and economic hazards to pine trees worldwide, especially affecting the coniferous forests and mixed forests of masson pine in subtropical regions of China. In order to prevent PWN disease expansion, the risk level and susceptivity of PWN outbreaks need to be predicted in advance. For this purpose, we established a prediction model to estimate the susceptibility and risk level of PWN with vegetation condition variables, anthropogenic activity variables, and topographic feature variables across a large-scale district. The study was conducted in Dangyang City, Hubei Province in China, which was located in a subtropical zone. Based on the location of PWN points derived from airborne imagery and ground survey in 2018, the predictor variables were conducted with remote sensing and geographical information system (GIS) data, which contained vegetation indices including normalized difference vegetation index (NDVI), normalized difference moisture index (NDMI), normalized burn ratio (NBR), and normalized red edge index (NDRE) from Sentinel-2 imagery in the previous year (2107), the distance to different level roads which indicated anthropogenic activity, topographic variables in including elevation, slope, and aspect. We compared the fitting effects of different machine learning algorithms such as random forest (RF), K-neighborhood (KNN), support vector machines (SVM), and artificial neural networks (ANN) and predicted the probability of the presence of PWN disease in the region. In addition, we classified PWN points to different risk levels based on the density distribution of PWN sites and built a PWN risk level model to predict the risk levels of PWN outbreaks in the region. The results showed that: (1) the best model for the predictive probability of PWN presence is the RF classification algorithm. For the presence prediction of the dead trees caused by PWN, the detection rate (DR) was 96.42%, the false alarm rate (FAR) was 27.65%, the false detection rate (FDR) was 4.16%, and the area under the receiver operating characteristic curve (AUC) was equal to 0.96; (2) anthropogenic activity variables had the greatest effect on PWN occurrence, while the effects of slope and aspect were relatively weak, and the maximum, minimum, and median values of remote sensing indices were more correlated with PWN occurrence; (3) modeling analysis of different risk levels of PWN outbreak indicated that high-risk level areas were the easiest to monitor and identify, while lower incidence areas were identified with relatively low accuracy. The overall accuracy of the risk level of the PWN outbreak was identified with an AUC value of 0.94. From the research findings, remote sensing data combined with GIS data can accurately predict the probability distribution of the occurrence of PWN disease. The accuracy of identification of high-risk areas is higher than other risk levels, and the results of the study may improve control of PWN disease spread

HCD-HG treatment led to reduced velocity of blood flow.

<p>A: Velocity of the blood flow in the caudal aorta (CA) was measured. An example of the red blood cell tracking was present in the CA. Each cell was tracked for more than 10 time points, and corresponding frames were produced; motion trajectory was estimated. Relative time and distance were used for the calculation of the velocity. Upper panel scale bar:40 µm; the beneath panel scale bar: 80 µm. B: The values of maximum, minimum, and mean velocities were compared between normal and HCD-HG treated group, HCD-HG treated group and HCD-HG+ pioglitazone or metformin group respectively by Student's t test (n>5 in each group). Asterisk (*): Comparison of flow velocity between control group and corresponding groups, p<0.05.</p

Lipid accumulation in vasculature.

<p>A: Apparent lipid accumulation (yellow) was observed. (a), (b), (c), (d) panels respectively show lipid deposits in different experimental groups. (a) Control group; (b) HCD-HG group; (c) Pioglitazone treatment group; (d) Metformin treatment group. White arrows point out the locations of lipid deposits. Scale bar  = 40 µm. B: Areas of the lipid accumulation were selected as the region of interest (ROI), and estimated by measuring the dimension of ROI. Using the Student t test, we found that the amount of lipid accumulation was significantly larger in the HCD-HG treated group than that in the control group (p<0.05). The addition of pioglitazone or metformin significantly reduced the lipid accumulation (p<0.05). Asterisk (*): Comparison of lipid accumulation between control group and HCD-HG group. Cross (†): Comparison of lipid accumulation between HCD-HG group and drug treatment groups, respectively.</p