A magnetic resonance conditional robot for lumbar spinal injection: Development and preliminary validation.

PURPOSE: This work presents the design and preliminary validation of a Magnetic Resonance (MR) conditional robot for lumbar injection for the treatment of lower back pain. METHODS: This is a 4-degree-of-freedom (DOF) robot that is 200 × 230 × 130 mm3 in volume and has a mass of 0.8 kg. Its lightweight and compact features allow it to be directly affixed to patient's back, establishing a rigid connection, thus reducing positional errors caused by patient movements during treatment. RESULTS: To validate the positioning accuracy of the needle by the robot, an electromagnetic (EM) tracking system and a needle with an EM sensor embedded in the tip were used for the free space evaluation with position accuracy of 0.88 ± 0.46 mm and phantom mock insertions using the Loop-X CBCT scanner with target position accuracy of 3.62 ± 0.92 mm. CONCLUSION: Preliminary experiments demonstrated that the proposed robot showed improvements and benefits in its rotation range, flexible needle adjustment, and sensor protection compared with previous and existing systems, offering broader clinical applications.

Pathogenicity and immunogenicity of a quadruple gene-deleted pseudorabies virus variant as a vaccine candidate.

Since late 2011, the PRV variants have emerged in China, characterized by the increased virulence. The traditional attenuated vaccines have proven insufficient in providing complete protection, resulting in substantial economic losses to swine industry. In this study, a vaccine candidate strain, ZJ01-ΔgI/gE/TK/UL21, carrying the quadruple gene deletion was derived from the previously generated three gene-deleted virus ZJ01-ΔgI/gE/TK. As anticipated, piglets inoculated with ZJ01-ΔgI/gE/TK/UL21 exhibited normal body temperatures and showed no viral shedding, consistent with the observations from piglets treated with ZJ01-ΔgI/gE/TK. Importantly, a significant higher level of interferon induction was observed among piglets in the ZJ01-ΔgI/gE/TK/UL21 group compared to those in the ZJ01-ΔgI/gE/TK group. Upon challenge with the PRV variant ZJ01, piglets immunized with ZJ01-ΔgI/gE/TK/UL21 exhibited reduced viral shedding compared to the ZJ01-ΔgI/gE/TK group. Furthermore, piglets vaccinated with ZJ01-ΔgI/gE/TK/UL21 exhibited minimal pathological lesions in brain tissues, similar to those in the ZJ01-ΔgI/gE/TK group. These results underscore the potential of ZJ01-ΔgI/gE/TK/UL21 as a promising vaccine for controlling PRV infection.

Robotic system for magnetic resonance imaging-guided high-intensity focus ultrasound application: Feasibility of breast fibroadenoma treatment.

PURPOSE: This paper presents a high-intensity focus ultrasound (HIFU) robotic system for treating breast fibroadenoma under the guidance of magnetic resonance imaging (MRI). Based on the thermal and mechanical effects of ultrasound, the system aims to deliver ultrasound energy to a target precisely without damaging the normal tissue. The temperature elevation can be monitored in real time by MRI, and the treatment plan can be adjusted during the procedure. The requirements, design specifications, control system and registration of the robotic system are specified. METHODS: The robotic system was designed with a 3 degrees of freedom manipulator with limit switches and encoders, a customised MRI-compatible breast coil, a water bladder with sets of breast-conforming brackets, and a probe capable of generating ultrasound. Twenty volunteers were recruited for this study, and their data were analysed to provide more precise data for the design. The accuracy of the robot was evaluated in free space using a coordinate measuring machine, phantom and ex vivo porcine tissue in MRI room. The study also verified the signal-to-noise ratio (SNR) of the MRI with the effect of the robotic system. RESULTS: The research findings revealed that the manipulator exhibited a translational precision of 0.10 ± 0.14 mm, a rotational fidelity around the X direction of 0.11 ± 0.09°, and an oscillatory exactness around the Y direction of 0.10 ± 0.08°. The investigation of positioning accuracy demonstrated that the robot's error in free space was 0.26 ± 0.07 mm. When subjected to MRI room with agar-silica phantom and ex vivo porcine tissue, the positioning accuracy amounted to 1.11 ± 0.47 mm and 1.57 ± 0.52 mm. In the presence of the robotic system, the SNR of the MRI experienced a 4.2% reduction, which had a negligible impact on image quality. CONCLUSIONS: The conducted experiments validate the efficacy of the proposed MRI-guided HIFU robotic system in executing agar-silica phantom and ex vivo porcine tissue investigations with adequate positioning accuracy. Consequently, this system exhibits certain feasibility for the treatment of breast fibroadenomas.

Fabrication of composite microneedles integrated with insulin-loaded CaCO3 microparticles and PVP for transdermal delivery in diabetic rats.

Dissolving microneedles (MNs) display high efficiency, safety and painless in transdermal delivery for poorly permeable drugs. Here, a dissolving composite MNs prepared from insulin-loaded CaCO3 microparticles (INS-CaCO3 MPs) and poly(vinyl pyrrolidone) (PVP) as matrix were fabricated with two-step centrifuging and molding process to immobilize insulin in the MNs. The as-prepared INS-CaCO3/PVP MNs exhibited remarkable mechanical strength and slower solubility properties when compared with pure PVP MNs. In vitro skin insertion capability was determined by staining with FITC-labeled insulin which was revealed after insertion, gradually diffusing from the puncture sites to deeper tissues. In vivo pharmacodynamic studies were then conducted to estimate the feasibility of the administration of insulin-loaded dissolving MNs on diabetic rats for glucose regulation. The relative pharmacological availability (RPA) and relative bioavailability (RBA) of insulin from MNs were 98.2 and 96.6%. Thus, this study suggests that the use of INS-CaCO3/PVP MNs achieved both high efficiency and constant release of insulin in comparison with the traditional subcutaneous injection approach and presented a promising device to delivery insulin for diabetic therapy.

Nitrogen-containing microporous conjugated polymers via carbazole-based oxidative coupling polymerization: preparation, porosity, and gas uptake.

Facile preparation of microporous conjugated polycarbazoles via carbazole-based oxidative coupling polymerization is reported. The process to form the polymer network has cost-effective advantages such as using a cheap catalyst, mild reaction conditions, and requiring a single monomer. Because no other functional groups such as halo groups, boric acid, and alkyne are required for coupling polymerization, properties derived from monomers are likely to be fully retained and structures of final polymers are easier to characterize. A series of microporous conjugated polycarbazoles (CPOP-2-7) with permanent porosity are synthesized using versatile carbazolyl-bearing 2D and 3D conjugated core structures with non-planar rigid conformation as building units. The Brunauer-Emmett-Teller specific surface area values for these porous materials vary between 510 and 1430 m(2) g(-1) . The dominant pore sizes of the polymers based on the different building blocks are located between 0.59 and 0.66 nm. Gas (H2 and CO2 ) adsorption isotherms show that CPOP-7 exhibits the best uptake capacity for hydrogen (1.51 wt% at 1.0 bar and 77 K) and carbon dioxide (13.2 wt% at 1.0 bar and 273 K) among the obtained polymers. Furthermore, its high CH4 /N2 and CO2 /N2 adsorption selectivity gives polymer CPOP-7 potential application in gas separation.