Evaluation of short-and medium-term efficacy and complications of ultrasound-guided ablation for small liver cancer

BACKGROUND To ensure clinical efficacy and prolong patient survival,treatments such as surgery and microwave ablation(MWA)are used for early liver cancer.MWA is preferred because it effectively preserves the normal liver tissue and causes transient coagulation necrosis of local liver tumor cells.However,due to technical limitations,the cancerous liver tissue cannot be completely ablated;therefore,the probability of local tumor recurrence is high.AIM To investigate the clinical efficacy and safety of ultrasound-guided percutaneous MWA in the treatment of small liver cancer.METHODS A total of 118 patients treated for small liver cancer in The Central Hospital of Yongzhou from January 2018 to April 2019 were selected.Sixty-six patients received ultrasound-guided percutaneous MWA(MWA group)and 52 received laparoscopic surgery(laparoscope group).The operation time,blood loss,hospital stay,and medical expenses of both groups were statistically analyzed.Serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),albumin(ALB),alpha fetal protein(AFP),carcinoembryonic antigen(CEA),and peripheral blood regulatory T lymphocytes(Treg)levels were evaluated pre-and post-operatively.The cross-sectional area of tumors measured before and after ablation was analyzed statistically;the therapeutic effect was compared between both groups in terms of surgical complications,2-year progression-free survival rate,and overall survival rate.RESULTS The operation time,blood loss,hospital stay,and medical expenses in the MWA group were lower than those of the laparoscope group,and the differences were significant(P<0.05);these parameters,and ALT,AST,TBIL,and ALB levels were compared preoperatively between both groups,and there was no significance(P>0.05).The operation time,blood loss,hospital stay,and medical expenses for 2 d and 1 wk after surgery,the ALT and AST of the MWA group were lower than those of the laparoscope group,and the difference was significant(P<0.05).The operation time,blood loss,hospital stay,and medical expenses,and serum AFP,CEA,and Treg levels were measured preoperatively and 4 and 8 wk postoperatively,and there were no significant differences between the two groups(P>0.05).Compared with preoperative levels,serum AFP,CEA,and Treg levels in both groups were decreased(P<0.05).The lesion in the MWA group had a maximum area of 4.86±0.90 cm2,1.24±0.57 cm2,and 0.31±0.11 cm2 preoperatively,1 and 3 mo postoperatively,respectively.Fifty-eight of them achieved complete response and eight achieved a partial response.After 2 years of followup,the progression-free and overall survival rates in the MWA group were 37.88%and 66.67%,respectively,compared with 44.23%and 76.92%in the laparoscope group,with no significant difference(P>0.05).CONCLUSION The effects of ultrasound-guided percutaneous MWA in the treatment of small liver cancer are similar to those of laparoscopic surgery.However,ablation causes less trauma and liver dysfunction.

Understanding Li roles in chemical reversibility of O2-type Li-rich layered cathode materials

Traditional O3-type Li-rich layered materials are attractive with ultra-high specific capacities,but suffering from inherent problems of voltage hysteresis and poor cycle performance.As an alternative,O2-type materials show the potential to improve the oxygen redox reversibility and structural stability.However,their structure-performance relationship is still unclear.Here,we investigate the correlation between the Li component and dynamic chemical reversibility of O2-type Li-rich materials.By exploring the formation mechanism of a series of materials prepared by Na/Li exchange,we reveal that insufficient Li leads to an incomplete replacement,and the residual Na in the Li-layer would hinder the fast diffusion of Li^(+).Moreover,excessive Li induces the extraction of interlayer Li during the melting chemical reaction stage,resulting in a reduction in the valence of Mn,which leads to a severe Jahn-Teller effect.Structural detection confirms that the regulation of Li can improve the cycle stability of Li-rich materials and suppress the trend of voltage fading.The reversible phase evolution observed in in-situ X-ray diffraction confirms the excellent structural stability of the optimized material,which is conducive to capacity retention.This work highlights the significance of modulating dynamic electrochemical performance through the intrinsic structure.

Modulation of lattice oxygen boosts the electrochemical activity and stability of Co-free Li-rich cathodes

Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,which leads to co-migration of transition metal ions and oxygen vacancies,causing structural instability.In this work,we propose a pre-activation strategy driven by chemical impregnation to modulate the chemical state of surface lattice oxygen,thus regulating the structural and electrochemical properties of the cathodes.In-situ X-ray diffraction confirms that materials based on activated oxygen configuration have higher structural stability.More importantly,this novel efficient strategy endows the cathodes having a lower surface charge transfer barrier and higher Li+transfer kinetics characteristic and ameliorates its inherent issues.The optimized cathode exhibits excellent electrochemical performance:after 300 cycles,high capacity(from 238 m Ah g^(-1)to 193 m Ah g^(-1)at 1 C)and low voltage attenuation(168 mV)are obtained.Overall,this modulated surface lattice oxygen strategy improves the electrochemical activity and structural stability,providing an innovative idea to obtain high-capacity Co-free Li-rich cathodes for next-generation Li-ion batteries.