Evaluation Method for Probability of Blowout after the Failure of Offshore Well Killing

249-259With the development of offshore oil industry, the influx and blowout are inevitable. Well control methods have been well researched, but how to recognize the failure of well control earlier and how to evaluate the probability of blowout for taking steps to avoid are imperfect. Based on the two-phase gas-liquid flow, the characteristic of well killing curve before and after killing are analyzed. Then the method for recognizing the failure of well killing is established by the probabilistic and covariance processing method. Then the blowout due to the failure of well killing is studied and the build-up pressure template is established. According to this, three evaluation methods for blowout probability are established, the shut-off pressure, the standing and casing pressure, formation parameters and underbalanced level varying methods. Final, four hardware systems and one evaluation system are recommended for decreasing or avoiding the risk during the failure of well killing

Experimental Study on the Down-Speed of Conductor Pipe Influenced by Jetting Displacement in Deepwater Drilling

Based on the theory of jet drilling technology and displacement optimization, a set of experimental equipment about jet drilling is devised. The laws of conductor pipe down-speed influenced by pump displacement were studied by laboratory experiments. According to the experimental results and analysis, the following conclusions can be drawn. The down-speed of conductor pipe increases with the increasing of displacement, also the drilling speed is boosted. But the unstableness of borehole wall is augmented as well. And this will result in the increasing of waiting time for borehole formation. In the process of conductor pipe jetting, the conductor pipe down-speed and the waiting time of soil returning to a certain bearing capacity should be considered together in order to shorten the entirety drilling time. The research can provide certain references for expensive offshore operation and have important significance to improve the economic benefits of deepwater drilling

Somatic mutation and gain of copy number of PIK3CA in human breast cancer

INTRODUCTION: Phosphatidylinositol 3-kinases (PI3Ks) are a group of lipid kinases that regulate signaling pathways involved in cell proliferation, adhesion, survival, and motility. Even though PIK3CA amplification and somatic mutation have been reported previously in various kinds of human cancers, the genetic change in PIK3CA in human breast cancer has not been clearly identified. METHODS: Fifteen breast cancer cell lines and 92 primary breast tumors (33 with matched normal tissue) were used to check somatic mutation and gene copy number of PIK3CA. For the somatic mutation study, we specifically checked exons 1, 9, and 20, which have been reported to be hot spots in colon cancer. For the analysis of the gene copy number, we used quantitative real-time PCR and fluorescence in situ hybridization. We also treated several breast cancer cells with the PIK3CA inhibitor LY294002 and compared the apoptosis status in cells with and without PIK3CA mutation. RESULTS: We identified a 20.6% (19 of 92) and 33.3% (5 of 15) PIK3CA somatic mutation frequency in primary breast tumors and cell lines, respectively. We also found that 8.7% (8 of 92) of the tumors harbored a gain of PIK3CA gene copy number. Only four cases in this study contained both an increase in the gene copy number and a somatic mutation. In addition, mutation of PIK3CA correlated with the status of Akt phosphorylation in some breast cancer cells and inhibition of PIK3CA-induced increased apoptosis in breast cancer cells with PIK3CA mutation. CONCLUSION: Somatic mutation rather than a gain of gene copy number of PIK3CA is the frequent genetic alteration that contributes to human breast cancer progression. The frequent and clustered mutations within PIK3CA make it an attractive molecular marker for early detection and a promising therapeutic target in breast cancer

A Raman/fluorescence dual-modal imaging guided synergistic photothermal and photodynamic therapy nanoplatform for precision cancer theranostics

Nanoparticle-based phototherapies, such as photodynamic therapy (PDT) and photothermal therapy (PTT) are effective methods for tumor theranostics. However, there are still some problems such as lack of specificity to the special internal environment and difficulty in tumor localization. In this study, we design a near-infrared (NIR) fluorescent guided tumor therapy nanoplatform Cy-C-S-NPs for tumor therapy and precise localization. First, we synthesized a near-infrared fluorescent dye Cy-DM, combined with excellent optical and PDT/PTT properties. Interestingly, it binds Cy7 to the azo bond and mercaptoacetic acid and in the meanwhile the azo bond can be broken specifically under the condition of tumor hypoxia. Then the Au-S bond is covalently coupled with C-S-NPs, a gold nanomaterial similar to waxberry with surface-enhanced Raman function, to form the Cy-C-S-NP nanomaterial and achieve Raman imaging. In a non-anoxic environment, Cy-DM fluorescence is quenched by C-S-NPs. The unique hypoxic microenvironment of tumor cells leads to the breaking of azo bonds, releasing Cy-DM and producing fluorescence. Accurate tumor localization based on near infrared imaging diagnosis and dependent on the release of Cy-DM and C-S-NPs, PDT/PTT therapy can be performed effectively. This study provides an interesting nanoplatform that combines the functions of PDT/PTT with dual imaging effects of fluorescence and Raman imaging. This multifunctional nanoplatform may be a promising nanoplatform for targeted tumor imaging and precision therapy

Analysis of influencing factors of job demands of healthcare workers working in mobile cabin hospitals in China

Abstract Aim To explore the job demands of healthcare workers (HCWs) working in mobile cabin hospitals in Shanghai and identify the influencing factors. Design The study had a cross‐sectional design. Methods Using the convenience sampling method, we selected 1223 HCWs (medical team members) working in these mobile cabin hospitals during April–May 2022. The findings of the general information questionnaire and the hierarchy scale of job demands of HCWs working in mobile cabin hospitals were used for the investigation. Results The total score of job demands of the included HCWs was 132.26 ± 9.53; the average score of the items was 4.73 ± 0.34. Multivariate linear regression analyses showed that the following HCWs had significantly higher job demands: female HCWs and HCWs who received psychological training or intervention during the COVID‐19 pandemic, were satisfied with the doctor/nurse–patient relationship, received support from family members/friends/colleagues, believed that the risk of working in mobile cabin hospitals was high, had adapted to the working environment of mobile cabin hospitals and had college/undergraduate level of education. They would benefit from increased social support and better training in terms of psychological coping mechanisms(both theoretical knowledge and applicable skills) and COVID‐19 prevention,control and treatment abilities

Molecular fluorescent probes for imaging and evaluation of peroxynitrite fluctuations in living cells and in vivo under hypoxic stress

Hypoxia stress causes cell damage and apoptosis by producing excessive reactive oxygen species (ROS), which is a universal concern in biology and medicine. Peroxynitrite (ONOO-) plays a vital part in the oxidative injury of tissue proteins in the pathogenic mechanism of many disorders, which is a one of ROS. Thus, excessive pro-duction of ONOO- may be one of the crucial factors leading to hypoxia stress injury. However, due to the unstable chemical property and strong reactivity of ONOO-, most of the existing detection ways cannot image and detect its level in real time. Herein, in order to selectively imaging and detecting ONOO- in living cells and in vivo, we synthesized a fluorescent probe Cy-CF3 (our fluorescent probe for detection of ONOO-). Cy-CF3 was capable of monitoring ONOO- with excellent sensitivity and selectivity. Using Cy-CF3, the relationship between hypoxia stress and ONOO- was evaluated. The probe was also employed to sense the change of ONOO- in zebrafish under hypoxia conditions as well as determine ONOO- in living mice with acute liver ischemia. Taken together, the proposed probe maybe a powerful chemical tool for the study of ONOO- in biological mechanisms

Polarization-insensitive 3D conformal-skin metasurface cloak

10.1038/s41377-021-00507-8Light: Science and Applications1017

Deterministic Approach to Achieve Full-Polarization Cloak

Achieving full-polarization (σ) invisibility on an arbitrary three-dimensional (3D) platform is a long-held knotty issue yet extremely promising in real-world stealth applications. However, state-of-the-art invisibility cloaks typically work under a specific polarization because the anisotropy and orientation-selective resonant nature of artificial materials made the σ-immune operation elusive and terribly challenging. Here, we report a deterministic approach to engineer a metasurface skin cloak working under an arbitrary polarization state by theoretically synergizing two cloaking phase patterns required, respectively, at spin-up (σ+) and spin-down (σ−) states. Therein, the wavefront of any light impinging on the cloak can be well preserved since it is a superposition of σ+ and σ− wave. To demonstrate the effectiveness and applicability, several proof-of-concept metasurface cloaks are designed to wrap over a 3D triangle platform at microwave frequency. Results show that our cloaks are essentially capable of restoring the amplitude and phase of reflected beams as if light was incident on a flat mirror or an arbitrarily predesigned shape under full polarization states with a desirable bandwidth of ~17.9%, conceiving or deceiving an arbitrary object placed inside. Our approach, deterministic and robust in terms of accurate theoretical design, reconciles the milestone dilemma in stealth discipline and opens up an avenue for the extreme capability of ultrathin 3D cloaking of an arbitrary shape, paving up the road for real-world applications