3D Dynamic Motion Planning for Robot-Assisted Cannula Flexible Needle Insertion into Soft Tissue

In robot-assisted needle-based medical procedures, insertion motion planning is a crucial aspect. 3D dynamic motion planning for a cannula flexible needle is challenging with regard to the nonholonomic motion of the needle tip, the presence of anatomic obstacles or sensitive organs in the needle path, as well as uncertainties due to the dynamic environment caused by the movements and deformations of the organs. The kinematics of the cannula flexible needle is calculated in this paper. Based on a rapid and robust static motion planning algorithm, referred to as greedy heuristic and reachability-guided rapidly-exploring random trees, a 3D dynamic motion planner is developed by using replanning. Aiming at the large detour problem, the convergence problem and the accuracy problem that replanning encounters, three novel strategies are proposed and integrated into the conventional replanning algorithm. Comparisons are made between algorithms with and without the strategies to verify their validity. Simulations showed that the proposed algorithm can overcome the above-noted problems to realize real-time replanning in a 3D dynamic environment, which is appropriate for intraoperative planning. © 2016 Author

A Review of Stimulation Technologies for Weakly-Consolidated Natural Gas Hydrate Reservoirs

As an unconventional clean resource with huge reserves and a wide distribution, natural gas hydrates (NGHs) have good application prospects. However, due to limited understanding and available production technology for NGHs, there is still a large gap between current production tests and commercial exploitation. A breakthrough in reservoir stimulation technologies is key to realizing the industrialization of NGHs in the future. Through a comprehensive summary of hydrate production test cases in Japan and China, this paper highlights the difficulties in the transformation of weakly-consolidated reservoirs. By systematically reviewing the theory and technology of hydrate reservoir transformation and engineering applications, this paper elucidates in detail the technical principles and mechanisms of several available stimulation technologies for weakly-consolidated reservoirs, and assesses the feasibility of their application to increase the production of NGHs. Existing problems and challenges are summarized and future prospects are discussed. Finally, suggestions are put forward for research and development of transformation technology for weakly-consolidated NGHs reservoirs in the future

The Research on Landslide Disaster Information Publishing System Based on WebGIS

AbstractBy analyzing the technique features and functions of WebGIS, combined with the landslide disaster characteristics of Lanzhou city, taken MapGIS K9-IMS as map release platform, the landslide disaster information publishing based on WebGIS of Lanzhou city is built. This paper has introduced the overall structure of the system and its functional characteristics, as well as analyzed the key technologies and methods to conduct the system briefly. The system adopts B/S frameworks of three layers, designs and conducts each of the functional modules based on the thoughts of modularization and routing. It includes three modules: rainfall management, warning analysis, warning management, with the warning analysis module as its core. Doing the secondary development based on the MapGIS K9-IMS platform, it can realize these functions: storage and management, query and retrieval, warning and analysis, Web publishing, decision-making of landslide disaster information, etc., which can provide decision support for local disaster prevention and mitigation

Co-incorporation of hydrotalcite and starch into biochar-based fertilizers for the synthesis of slow-release fertilizers with improved water retention

Abstract The unsatisfactory nutrient slow-release and water-retention performance of traditional biochar-based compound fertilizers (BCF) severely limit their practical application. Herein, a new type of slow-release fertilizer with high water retention was fabricated via the incorporation of hydrotalcite and starch into BCF, named as HS-BCF. The water-retention and nutrient releasing performance of the prepared HS-BCF and related nutrient slow-release mechanism were investigated. The results showed that the incorporation of hydrotalcite and starch into BCF could increase the soil water-retention ratio by 5–10% points. The accumulated N, P, and K leaching amounts of HS-BCF in soil within 30 days  were 49.4%, 13.3%, and 87.4% of BCF at most, respectively. Kinetic analysis indicated that the release of nutrients from HS-BCF was attributed to the coupling of the diffusion-controlled and relaxation-controlled mechanism. Moreover, hydrotalcite could bind with P in HS-BCF, contributing to the enhanced durability of P in HS-BCF. Finally, pot experiments showed that the N–P–K utilization efficiencies of HS-BCF were all higher than those of BCF due to a better synchronization between the nutrient release of HS-BCF and the uptake of tomato plants. Overall, the study may provide a promising strategy for simultaneously improving the water-retention and slow-release performance of traditional biochar-based fertilizers. Graphical Abstrac

How a Short-Lived Rumor of Residential Redevelopment Disturbs a Local Housing Market: Evidence from Hangzhou, China

This paper investigates how a short-lived rumor of residential redevelopment triggered herding trading and housing price overreactions in a local housing market in Hangzhou. Through event studies, we find that herding purchasing caused a short-term housing price overreaction. Simultaneously, existing homeowners became reluctant to sell, and the number of new listings for sale decreased temporarily. However, we find no evidence of a decrease in market efficiency. A herding investor who purchased an average home may have suffered a loss of CNY 593,907 after the rumor weakened, equivalent to 8.7 years of income for an average resident in Hangzhou in 2021. This study reveals the importance of government policy communication, and the detrimental impact of ambiguous urban renewal policies on housing market stability and wealth redistribution

Identification of key genes and modules in response to Cadmium stress in different rice varieties and stem nodes by weighted gene co-expression network analysis

Abstract Soil cadmium (Cd) pollution threatens food safety. This study aimed to identify genes related to Cd accumulation in rice. Low- (Shennong 315, short for S315) and high- (Shendao 47, short for S47) Cd-accumulative rice cultivars were incubated with CdCl2·2.5H2O. RNA-seq and weighted gene co-expression network analysis (WGCNA) were performed to identify the modules and genes associated with Cd-accumulative traits of rice. After Cd stress treatment, the Cd content in various tissues of S315 was significantly higher than that of S47. In the stem nodes, the Cd distribution results of the two varieties indicated that the unelongated nodes near the root (short for node A) had a stronger ability to block Cd transfer upwards than the panicle node (short for node B). Cd stress induced huge changes in gene expression profiles. After analyzing the differentially expressed genes (DEGs) in significantly correlated WGCNA modules, we found that genes related to heavy metal transportation had higher expression levels in node A than that in node B, such as Copper transporter 6 (OS04G0415600), Zinc transporter 10 (OS06G0566300), and some heavy-metal associated proteins (OS11G0147500, OS03G0861400, and OS10G0506100). In the comparison results between S315 and S47, the expression of chitinase (OS03G0679700 and OS06G0726200) was increased by Cd treatment in S315. In addition, OsHSPs (OS05G0460000, OS08G0500700), OsHSFC2A (OS02G0232000), and OsDJA5 (OS03G0787300) were found differentially expressed after Cd treatment in S315, but changed less in S47. In summary, different rice varieties have different processes and intensities in response to Cd stress. The node A might function as the key tissue for blocking Cd upward transport into the panicle via vigorous processes, including of heavy metal transportation, response to stress, and cell wall

Using a Material Library to Understand the Impacts of Raw Material Properties on Ribbon Quality in Roll Compaction

The purpose of this study is to use a material library to investigate the effect of raw material properties on ribbon tensile strength (TS) and solid fraction (SF) in the roll compaction (RC) process. A total of 81 pharmaceutical materials, including 53 excipients and 28 natural product powders (NPPs), were characterized by 22 material descriptors and were compacted under five different hydraulic pressures. The transversal and longitudinal splitting behaviors of the ribbons were summarized. The TS-porosity and TS-pressure relationships were used to explain the roll compaction behavior of powdered materials. Through defining the target ribbon quality (i.e., 0.6 ≤ SF ≤ 0.8 and TS ≥ 1 MPa), the roll compaction behavior classification system (RCBCS) was built and 81 materials were classified into three categories. A total of 24 excipients and five NPPs were classified as Category I materials, which fulfilled the target ribbon quality and had less occurrence of transversal splitting. Moreover, the multivariate relationships between raw material descriptors, the hydraulic pressure and ribbon quality attributes were obtained by PLS regression. Four density-related material descriptors and the cohesion index were identified as critical material attributes (CMAs). The multi-objective design space summarizing the feasible material properties and operational region for the RC process were visualized. The RCBCS presented in this paper enables a formulator to perform the initial risk assessment of any new materials, and the data modeling method helps to predict the impact of formulation ingredients on strength and porosity of compacts