PRSCS-Net: Progressive 3D/2D rigid Registration network with the guidance of Single-view Cycle Synthesis.

The 3D/2D registration for 3D pre-operative images (computed tomography, CT) and 2D intra-operative images (X-ray) plays an important role in image-guided spine surgeries. Conventional iterative-based approaches suffer from time-consuming processes. Existing learning-based approaches require high computational costs and face poor performance on large misalignment because of projection-induced losses or ill-posed reconstruction. In this paper, we propose a Progressive 3D/2D rigid Registration network with the guidance of Single-view Cycle Synthesis, named PRSCS-Net. Specifically, we first introduce the differentiable backward/forward projection operator into the single-view cycle synthesis network, which reconstructs corresponding 3D geometry features from two 2D intra-operative view images (one from the input, and the other from the synthesis). In this way, the problem of limited views during reconstruction can be solved. Subsequently, we employ a self-reconstruction path to extract latent representation from pre-operative 3D CT images. The following pose estimation process will be performed in the 3D geometry feature space, which can solve the dimensional gap, greatly reduce the computational complexity, and ensure that the features extracted from pre-operative and intra-operative images are as relevant as possible to pose estimation. Furthermore, to enhance the ability of our model for handling large misalignment, we develop a progressive registration path, including two sub-registration networks, aiming to estimate the pose parameters via two-step warping volume features. Finally, our proposed method has been evaluated on a public dataset CTSpine1k and an in-house dataset C-ArmLSpine for 3D/2D registration. Results demonstrate that PRSCS-Net achieves state-of-the-art registration performance in terms of registration accuracy, robustness, and generalizability compared with existing methods. Thus, PRSCS-Net has potential for clinical spinal disease surgical planning and surgical navigation systems.

Metal stable isotopes fractionation during adsorption.

Isotope technology is an ideal tool for tracing the sources of certain pollutants or providing insights into environmental processes. In recent years, the advent of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has enabled the precise measurement of various metal stable isotopes. Due to the presence of "fingerprint" properties in various environmental samples, metal stable isotopes have been applied to distinguish the source of contaminants effectively and further understand the corresponding environmental processes. The environmental fate of metal elements is strongly controlled by adsorption, an essential process for the distribution of elements between the dissolved and particulate phases. The adsorption of metal elements on mineral and organic surfaces significantly affects their biogeochemical cycles in the environment. Therefore, it is crucial to elucidate the fractionation characteristics of stable metal isotopes during the adsorption process. In this review, three typical transitional metal elements were selected, considering Mo as the representative of anionic species and Fe and Zn as the representative of cationic species. For Mo, the heavier Mo isotope is preferentially adsorbed in the solution phase, pH has a more significant influence on isotope fractionation, and temperature and ionic strength are relatively insensitive. Differences in coordination environments between dissolved and adsorbed Mo during adsorption, i.e., attachment mode (inner- or outer-sphere) or molecular symmetry (e.g., coordination number and magnitude of distortion), are likely responsible for isotopic fractionation. For Fe, The study of equilibrium/kinetic Fe isotopic fractionation in aqueous Fe(II)-mineral is not simple. The interaction between aqueous Fe(II) and Fe (hydroxyl) oxides is complex and dynamic. The isotope effect is due to coupled electron and atom exchange between adsorbed Fe(II), aqueous Fe(II), and reactive Fe(III) on the surface of Fe (hydroxyl) oxide. For Zn, the heavier Fe isotope preferentially adsorbs on the solid phase, and pH and ionic strength are essential influencing factors. The difference in coordination environment may be the cause of isotope fractionation.

Responses of rhizosphere microbial community structure and metabolic function to heavy metal coinhibition.

Metal mineral mining results in releases of large amounts of heavy metals into the environment, and it is necessary to better understand the response of rhizosphere microbial communities to simultaneous stress from multiple heavy metals (HMs), which directly impacts plant growth and human health. In this study, by adding different concentrations of cadmium (Cd) to a soil with high background concentrations of vanadium (V) and chromium (Cr), the growth of maize during the jointing stage was explored under limiting conditions. High-throughput sequencing was used to explore the response and survival strategies of rhizosphere soil microbial communities to complex HM stress. The results showed that complex HMs inhibited the growth of maize at the jointing stage, and the diversity and abundance of maize rhizosphere soil microorganisms were significantly different at different metal enrichment levels. In addition, according to the different stress levels, the maize rhizosphere attracted many tolerant colonizing bacteria, and cooccurrence network analysis showed that these bacteria interacted very closely. The effects of residual heavy metals on beneficial microorganisms (such as Xanthomonas, Sphingomonas, and lysozyme) were significantly stronger than those of bioavailable metals and soil physical and chemical properties. PICRUSt analysis revealed that the different forms of V and Cd had significantly greater effects on microbial metabolic pathways than all forms of Cr. Cr mainly affected the two major metabolic pathways: microbial cell growth and division and environmental information transmission. In addition, significant differences in rhizosphere microbial metabolism under different concentrations were found, and this can serve as a reference for subsequent metagenomic analysis. This study is helpful for exploring the threshold for the growth of crops in toxic HM soils in mining areas and achieving further biological remediation.

Role of tailing colloid from vanadium-titanium magnetite in the adsorption and cotransport with vanadium.

The geochemical cycling of vanadium (V) in mining areas has attracted much attention. However, little knowledge was about the effects of tailing colloids on the fate and transport of vanadium in tailing reservoirs which was ignored before. This study investigated the interactions of tailing colloids from vanadium-titanium magnetite with vanadium. Colloid characterization, tailing leaching, adsorption, and column experiments of single and cotransport of tailing colloid with V were conducted. Results show that 98.08% V in the vanadium-titanium magnetite tailing was in the residual state with limited leachable V under various conditions. The adsorption of V to the tailing colloid was via electrostatic attraction and surface complexation on the heterogeneously distributed sorption sites on the colloid surface. The adsorption control step was the diffusion of V into the tailing colloid pores. The increase in pH and the decrease in ionic strength (IS) promoted the single transport of tailing colloid and V in quartz sand columns. In cotransport scenarios, V promoted the transport of tailing colloids via the surface coating effect. In contrast, the transport of V was retarded by the adsorbed tailing colloid on the quartz sand surface. The pre-adsorbed V in the column enhanced the subsequent transport of tailing colloids by electrical repulsion, while the pre-adsorbed tailing colloids facilitated the subsequent transport of V via cotransport of the released colloids with V. The high mobility of the tailing colloid and V and their cotransport in the porous media highly demonstrated the potential V pollution pathways that need to be taken into account.

[Expression and purification of GST-Rta fusion protein from EB virus and preparation of the polyclonal antibody against GST-Rta].

OBJECTIVE: To obtain the recombinant fusion proteins GST-Rta185 and GST-Rta150 from EB virus and prepare two Rta protein specific polyclonal antibodies, respectively. METHODS: Plasmids pGEX-R1501, pGEX-R1851 and pGEX-5X-3 were separately transformed into Escherichia coli BL21 (DE3). Expressions of the recombinant proteins R150-GST, R185-GST and free GST were induced by 0.1 mmol/L IPTG in LB medium. The expressed proteins were purified from lysates with Glutathione Sepharose 4B. Purified proteins were mixed with Freund's adjuvant and then were used to immunize rabbits. RESULTS: High levels of expression of target proteins were detected in the lysates and the purified proteins were obtained by affinity chromatography with Glutathione Sepharose 4B. Western blot and ELISA analysis suggested that the polyclonal antibodies against GST-R185 and GST-R150 were specific. CONCLUSION: The antiserums have good specificity. They are important for the research on Rta fusion proteins from EB virus and for the diagnosis or treatment of EB virus associated diseases.