Reversible Mn^(2+)/Mn^(4+)double-electron redox in P3-type layer-structured sodium-ion cathode

The balance between cationic redox and oxygen redox in layer-structured cathode materials is an important issue for sodium batteries to obtain high energy density and considerable cycle stability.Oxygen redox can contribute extra capacity to increase energy density,but results in lattice instability and capacity fading caused by lattice oxygen gliding and oxygen release.In this work,reversible Mn^(2+)/Mn^(4+)redox is realized in a P3-Na_(0.65)Li_(0.2)Co_(0.05)Mn_(0.75)O_(2)cathode material with high specific capacity and structure stability via Co substitution.The contribution of oxygen redox is suppressed significantly by reversible Mn^(2+)/Mn^(4+)redox without sacrificing capacity,thus reducing lattice oxygen release and improving the structure stability.Synchrotron X-ray techniques reveal that P3 phase is well maintained in a wide voltage window of 1.5-4.5 V vs.Na^(+)/Na even at 10 C and after long-term cycling.It is disclosed that charge compensation from Co/Mn-ions contributes to the voltage region below 4.2 V and O-ions contribute to the whole voltage range.The synergistic contributions of Mn^(2+)/Mn^(4+),Co^(2+)/Co^(3+),and O^(2-)/(O_n)^(2-)redox in P3-Na_(0.65)Li_(0.2)Co_(0.05)Mn_(0.75)O_(2)lead to a high reversible capacity of 215.0 m A h g^(-1)at 0.1 C with considerable cycle stability.The strategy opens up new opportunities for the design of high capacity cathode materials for rechargeable batteries.

Interaction between cyclooxygenase-2,Snail,and E-cadherin in gastric cancer cells

AIM:To investigate the mechanisms of how cyclooxygenase-2(COX-2)regulates E-cadherin in gastric cancer cells.METHODS:COX-2 expression in human gastric cancer cell lines SGC-7901,BGC-823,MGC-803 and AGS were measured at the mRNA and protein level.COX-2 rich cell line SGC-7901 was chosen for subsequent experiments.siRNA mediated gene knockdown was used to investigate the impact of COX-2 on nuclear factor-κB (NF-κB),Snail,and E-cadherin in gastric cancer cells.Gene expression was determined by Western blot and real-time polymerase chain reaction.To analyze whether NF-κB inhibition could interrupt the modulatory effect of COX-2 or prostaglandin E2(PGE2)on E-cadherin,gastric cancer cells were treated with celecoxib or PGE2,in the presence of NF-κB specific siRNA.RESULTS:Highest expression level of COX-2 was found in SGC-7901 cells,both at mRNA and protein levels.siRNA mediated down-regulation of COX-2 led to a reduced expression of NF-κB and Snail,but an increased expression of E-cadherin in SGC-7901 cells.siRNA mediated down-regulation of NF-κB also led to a reduced expression of E-cadherin and Snail in SGC-7901 cells.However,COX-2 expression did not alter after cells were treated with NF-κB specific siRNA in SGC-7901 cells.Treatment of SGC-7901 cells with celecoxib led to a reduced expression of Snail but an increased expression of E-cadherin.In contrast,treatment of SGC-7901 cells with PGE2 led to an increased Snail and a decreased E-cadherin.However,siRNAmediated knockdown of NF-κB partially abolished the effect of celecoxib and PGE2 on the regulation of E-cadherin and Snail in SGC-7901 cells.CONCLUSION:COX-2 likely functions upstream of NF-κB and regulates the expression of E-cadherin via NF-κB/Snail signaling pathway in gastric cancer cells.

Suppressing irreversible phase transition and enhancing electrochemical performance of Ni-rich layered cathode LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) by fluorine substitution

Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,mainly due to the irreversible structure change at high voltage.Herein,we demonstrate that F substitution with the appropriate amount(1 at%)is capable for improve the electrochemical performance of LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cathode significantly.It is revealed that F substitution can reduce cation mixing,stabilize the crystal structure and improve Li transport kinetics.The resulted LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(1.99)F_(0.01)cathode can deliver a high capacity of 194.4 mAh g^(-1) with capacity retention of 95.5%after 100 cycles at 2 C and 165.2 mAh g^(-1) at 5 C.In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes,ensuring a long-term cycle stability.

Knockdown of Microtubule Associated Serine/threonine Kinase Like Expression Inhibits Gastric Cancer Cell Growth and Induces Apoptosis by Activation of ERK1/2 and Inactivation of NF-κB Signaling

Microtubule-associated serine/threonine kinase(MASTL)functions to regulate chromosome condensation and mitotic progression.Therefore,aberrant MASTL expression is commonly implicated in various human cancers.This study analyzed MASTL expression in gastric cancer vs.adjacent normal tissue for elucidating the association with clinicopathological data from patients.This work was then extended to investigate the effects of MASTL knockdown on tumor cells in vitro.The level of MASTL expression in gastric cancer tissue was assessed from the UALCAN,GEPIA,and Oncomine online databases.Lentivirus carrying MASTL or negative control shRNA was infected into gastric cancer cells.RT-qPCR,Western blotting,cell viability,cell counting,flow cytometric apoptosis and cell cycle,and colony formation assays were performed.MASTL was upregulated in gastric cancer tissue compared to the adjacent normal tissue,and the MASTL expression was associated with advanced tumor stage,Helicobacter pylori infection and histological subtypes.On the other hand,knockdown of MASTL expression significantly reduced tumor cell viability and proliferation,and arrested cell cycle at G2/M stage but promoted tumor cells to undergo apoptosis.At protein level,knockdown of MASTL expression enhanced levels of cleaved PARP1,cleaved caspase-3,Bax and p-ERK1/2 expression,but downregulated expression levels of BCL-2 and p-NF-κB-p65 protein in AGS and MGC-803 cells.MASTL overexpression in gastric cancer tissue may be associated with gastric cancer development and progression,whereas knockdown of MASTL expression reduces tumor cell proliferation and induces apoptosis.Further study will evaluate MASTL as a potential target of gastric cancer therapeutic strategy.

Acute esophageal obstruction caused by reverse migration of gastric bezoars: A case report

BACKGROUND Bezoars can be found anywhere in the gastrointestinal tract.Esophageal bezoars are rare.Esophageal bezoars are classified as either primary or secondary.It is rarely reported that secondary esophageal bezoars caused by reverse migration from the stomach lead to acute esophageal obstruction.Guidelines recommend urgent upper endoscopy(within 24 h)for these impactions without complete esophageal obstruction and emergency endoscopy(within 6 h)for those with complete esophageal obstruction.Gastroscopy is regarded as the mainstay for the diagnosis and treatment of esophageal bezoars.CASE SUMMARY A 59-year-old man was hospitalized due to nausea,vomiting and diarrhea for 2 d and sudden retrosternal pain and dysphagia for 10 h.He had a history of type 2 diabetes mellitus for 9 years.Computed tomography revealed dilated lower esophagus,thickening of the esophageal wall,a mass-like lesion with a flocculent high-density shadow and gas bubbles in the esophageal lumen.On gastroscopy,immovable brown bezoars were found in the lower esophagus,which led to esophageal obstruction.Endoscopic fragmentation was successful,and there were no complications.The symptoms of retrosternal pain and dysphagia disappeared after treatment.Mucosal superficial ulcers were observed in the lower esophagus.Multiple biopsy specimens from the lower esophagus revealed nonspecific findings.The patient remained asymptomatic,and follow-up gastroscopy 1 wk after endoscopic fragmentation showed no evidence of bezoars in the esophagus or the stomach.CONCLUSION Acute esophageal obstruction caused by bezoars reversed migration from the stomach is rare.Endoscopic fragmentation is safe,effective and minimally invasive and should be considered as the first-line therapeutic modality.

Effects of nociceptin/orphanin FQ on rats with cathartic colon

AIM： To demonstrate the change and effect of nodceptin/orphanin FQ in the colon of rats with cathartic colon. METHODS： The cathartic colon model was established by feeding rats rhubarb for 3 mo, the changes of colonic electromyography were investigated by both suspension muscle strips test and serosal recordings of colonic myoelectrical activity. Immunohistochemical staining （S-P methods） and image analysis were used to determine the changes of nociceptin/orphanin FQ in the proximal colon and distal colon of rats with cathartic colon. RESULTS： Suspension muscle strips test in vitro showed OFQ （10^-9-10^-6 mol/L） concentration dependently caused an immediate tonic contraction in the isolated colon. But the increase of tension in cathartic colon was less than control groups （P〈0.01）. Intravenous administration of OFQ （1 μg/kg） caused phasic contractions in the proximal colon, while the amplitude of phasic contractions caused by OFQ in cathartic colon was much lower than that in the control groups （2.58±0.41 vs 4.16 ± 0.53, t = -2.6, P = 0.012）. OFQ was highly expressed in the myenteric plexus of the rat colon but not in the musde cells. The immunoreactivity of OFQ in the proximal colon in cathartic colon rats decreased significantly compared with the control group （P = 0.001）. CONCLUSION： Colonic smooth muscle of cathartic colon showed low sensitivity to the stimulation of OFQ, suggesting that it might be caused by the abnormal distribution of OFQ or the abnormalities of receptors, leading to the disorganization of dynamic and incoordinated contractions.

Activating AIN thin film by introducing Co nanoparticles as a new anode material for thin-film lithium batteries

A1N/Co nanocomposite thin films were fabricated by pulsed laser deposition and investigated as new anode materials for lithium-ion batteries for the first time. The combination of electrochemically inactive A1N and Co in nanometer scale boosted the electrochemical performance of the thin films surprisingly. A high reversible capacity of 555 mAh.g^-1 after 100 discharge-charge cycles at a current density of 500 mA.g^-1 is obtained for the A1N/Co nanocomposite thin films, and 372 mAh.g^-1 can be retained at a high rate up to 16C, exhibiting promising cycle stability and rate capability. The electrochemical reaction mechanism study reveals that Co nanoparticles could not only provide high electronic conductivity for the thin films, which facilitate the thorough decomposition of A1N in the initial discharge process, but also react with Li3N to form a new species CozN during charge process, thus ensuring large capacity and high reversibility of A1N/Co nanocomposite thin films in sub- sequent cycles. This study provides a new perspective to design advanced electrode materials for lithium-ion batteries.

In situ formed synaptic Zn@LiZn host derived from ZnO nanofiber decorated Zn foam for dendrite-free lithium metal anode

Lithium metal is regarded as the most promising anode material for next generation high energy density lithium batteries due to its high theoretical capacity and lowest potential versus standard hydrogen electrode.However,lithium dendrite growth and huge volume change during cycling hinder its practical application.It is of great importance to design advanced Li metal anodes to solve these problems.Herein,we report a ZnO-coated Zn foam as the host matrix to pre-store lithium through thermal infusing,achieving a Zn@ZnO foam supported Li composite electrode(LZO).Needlelike ZnO nanofibers grown on the Zn foam greatly increase the surface area and enhance the lithiophilicity of the Zn foam.In situ formed synaptic LiZn layer after lithium infusion can disperse local current density and lower Li diffusion barrier effectively,leading to homogeneous Li deposition behavior,thus suppressing dendrite formation.The porous Zn foam skeleton can accommodate volume variation of the electrode during longterm cycling.Benefiting from these merits,the LZO anode exhibits much better cycle stability and rate capability in both symmetrical and full cells with low voltage hysteresis than the bare Li anode.This work opens a new opportunity in designing high performance composite Li anode for lithium-metal batteries.

Sputtered MoN nanolayer as a multifunctional polysulfide catalyst for high-performance lithium–sulfur batteries

Two major obstacles for the practical application of lithium–sulfur batteries are sluggish redox kinetics and the shuttle effect of lithium polysulfides(LiPSs).Herein,MoN nanolayer-decorated multilayer graphene is fabricated via magnetron sputtering then serves as a multifunctional interlayer in Li–S batteries to suppress the shuttle effect and enhance redox kinetics.It is revealed that after the initial discharge process,the MoN layers break up into independent microreaction units consisting of MoN bodies and MoS_(2) edges,forming a heterogeneous composite catalyst in situ.The MoN bodies not only have high sulfur affinity to trap LiPSs but also enhance their redox kinetics.At the same time,the MoS_(2) edge weakens the mobility of LiPSs via the anchoring effect.As a result,Li–S cells using the interlayer present superior cycling stability under a high sulfur loading of 4.8 mg cm^(-2).This work may open a new avenue for developing high-performance Li–S batteries.