Research into magnetic guidance technology for directional drilling in SAGD horizontal wells

SAGD horizontal wells are used to enhance oil recovery from heavy oil reservoirs.This technology requires precise separation between the production well and the injection well to ensure the efficient drainage of the reservoir.By studying the attitude of the downhole probe tube and the production well trajectory,an algorithm is proposed for eliminating ferromagnetic interference while drilling injection wells.A high accuracy filter circuit has been designed to correct the detected magnetic signals,which are ultra-weak,frequency-instable,and narrow-band.The directional drilling magnetic guidance system（DD-MGS） has been developed by integrating these advanced techniques.It contains a sub-system for the ranging calculation software,a magnetic source,a downhole probe tube and a sub-system for collecting ＆ processing the detected signals.The DD-MGS has succeeded in oilfield applications.It can guide the directional drilling trajectory not only in the horizontal section but also in the build section of horizontal injection wells.This new technology has broad potential applications.

visual bone marrow mesenchymal stem cell transplantation in the repair of spinal cord injury

An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T7_8. Superparamagnet- ic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cord via the subarachnoid space. An outer magnetic field was used to successfully guide the labeled cells to the lesion site. Prussian blue staining showed that more bone marrow mesen- chymal stem cells reached the lesion site in these rats than in those without magnetic guidance or snperparamagnetic iron oxide labeling, and immunofluorescence revealed a greater number of complete axons at the lesion site. Moreover, the Basso, Beattie and Bresnahan （BBB） locomotor rating scale scores were the highest in rats with superparamagnetic labeling and magnetic guid- ance. Our data confirm that superparamagnetic iron oxide nanoparticles effectively label bone marrow mesenchymal stem cells and impart sufficient magnetism to respond to the external magnetic field guides. More importantly, superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells can be dynamically and non-invasively tracked in vivo using magnetic resonance imaging. Superparamagnetic iron oxide labeling of bone marrow mesenchymal stem cells coupled with magnetic guidance offers a promising avenue for the clinical treatment of spinal cord injury.

Magnet-targeted delivery of bone marrow-derived mesenchymal stem cells improves therapeutic efficacy following hypoxic-ischemic brain injury

hypoxicischemic brain injury;however,the therapeutic efficacy of bone marrow-derived mesenchymal stem cells largely depends on the number of cells that are successfully transferred to the target.Magnet-targeted drug delivery systems can use a specific magnetic field to attract the drug to the target site,increasing the drug concentration.In this study,we found that the double-labeling using superparamagnetic iron oxide nanoparticle and poly-L-lysine(SPIO-PLL)of bone marrow-derived mesenchymal stem cells had no effect on cell survival but decreased cell proliferation 48 hours after labeling.Rat models of hypoxic-ischemic brain injury were established by ligating the left common carotid artery.One day after modeling,intraventricular and caudal vein injections of 1×105 SPIO-PLL-labeled bone marrow-derived mesenchymal stem cells were performed.Twenty-four hours after the intraventricular injection,magnets were fixed to the left side of the rats’heads for 2 hours.Intravoxel incoherent motion magnetic resonance imaging revealed that the perfusion fraction and the diffusion coefficient of rat brain tissue were significantly increased in rats treated with SPIO-PLL-labeled cells through intraventricular injection combined with magnetic guidance,compared with those treated with SPIO-PLL-labeled cells through intraventricular or tail vein injections without magnetic guidance.Hematoxylin-eosin and terminal deoxynucleotidyl transferase dUTP nick-end labeling(TUNEL)staining revealed that in rats treated with SPIO-PLL-labeled cells through intraventricular injection under magnetic guidance,cerebral edema was alleviated,and apoptosis was decreased.These findings suggest that targeted magnetic guidance can be used to improve the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for hypoxic-ischemic brain injury.This study was approved by the Animal Care and Use Committee of The Second Hospital of Dalian Medical University,China(approval No.2016-060)on March 2,2016.

Magnetic field-mediated Janus particles with sustained driving capability for severe bleeding control in perforating and inflected wounds

Severe bleeding in perforating and inflected wounds with forky cavities or fine voids encountered during prehospital treatments and surgical procedures is a complex challenge.Therefore,we present a novel hemostatic strategy based on magnetic field-mediated guidance.The biphasic Janus magnetic particle(MSS@Fe2O3-T)comprised aggregates ofα-Fe2O3 nanoparticles(Fe_(2)O_(3) NPs)as the motion actuator,negatively modified microporous starch(MSS)as the base hemostatic substrate,and thrombin as the loaded hemostatic drug.Before application,the particles were first wrapped using NaHCO_(3) and then doped with protonated tranexamic acid(TXA-NH_(3)^(+)),which ensured their high self-dispersibility in liquids.During application,the particles promptly self-diffused in blood by bubble propulsion and travelled to deep bleeding sites against reverse rushing blood flow under magnetic guidance.In vivo tests confirmed the superior hemostatic performance of the particles in perforating and inflected wounds(“V”-shaped femoral artery and“J”-shaped liver bleeding models).The present strategy,for the first time,extends the range of magnetically guided drug carriers to address the challenges in the hemorrhage control of perforating and inflected wounds.

Microcluster colloidosomes for hemostat delivery into complex wounds:A platform inspired by the attack action of torpedoes

Complex yet lethal wounds with uncontrollable bleeding hinder conventional hemostats from clotting blood at the source or deep sites of injury vasculature,thereby causing massive blood loss and significantly increased mortality.Inspired by the attack action of torpedoes,we synthesized microcluster(MC)colloidosomes equipped with magnetic-mediated navigation and“blast”systems to deliver hemostats into the cavity of vase-type wounds.CaCO_(3)/Fe_(2)O_(3)(CF)microparticles functionalized with Arg-Gly-Asp(RGD)modified polyelectrolyte multilayers were co-assembled with oppositely charged zwitterionic carbon dots(CDs)to form MC colloidosomes,which were loaded with thrombin and protonated tranexamic acid(TXA-NH_(3)^(+)).The composite microparticles moved against blood flow under magnetic mediation and simultaneously disassembled for the burst release of thrombin stimulated by TXA-NH_(3)^(+).The CO_(2) bubbles generated during disassembly produced a“blast”that propelled thrombin into the wound cavity.Severe bleeding in a vase-type hemorrhage model in the rabbit liver was rapidly controlled within~60 s.Furthermore,in vivo subcutaneous muscle and liver implantation models demonstrated excellent biodegradability of MC colloidosomes.This study is the first to propose a novel strategy based on the principle of torpedoes for transporting hemostats into vase-type wounds to achieve rapid hemostasis,creating a new paradigm for combating trauma treatment.