Influence of Helicobacter pylori infection on ghrelin levels in children

AIM:To compare ghrelin levels in plasma and gastric mucosa before and after Helicobacter pylori(H.pylori) treatment in children with H.pylori-associated functional dyspepsia.METHODS:Children with H.pylori-associated functional dyspepsia were enrolled in this study.H.pylori infection was confirmed by positive bacterial culture results.All of the children received triple H.pylori eradication therapy(a 2 wk course of omeprazole,amoxicillin,and clarithromycin).The children were divided into two groups based on the success of the H.pylori treatment:group 1(eradicated)-patients who had a negative 13C-urea breath test 2 mo after the end of therapy;and group 2(non-eradicated)-patients who had a positive 13C-urea breath test.Plasma ghrelin,gastric ghrelin mRNA,and the body mass index were evaluated in both groups before and after the H.pylori treatment.The plasma ghrelin levels were measured by a radioimmunoassay.The expression of gastric ghrelin mRNA was determined by real-time reverse transcription polymerase chain reaction.RESULTS:A total of 50 children with H.pylori-associated functional dyspepsia were treated with triple H.pylori eradication therapy.The mean age of the children was 5.52 ± 0.83 years,and there were 28 males and 22 females.Among the 50 H.pylori-positive children,30 successfully achieved eradication,and 20 did not.The mean plasma ghrelin levels of group 1 were 22.17 ± 1.73 ng/L and 26.59 ± 2.05 ng/L before and after the treatment,respectively,which was a significant increase(P = 0.001).However,the mean plasma ghrelin level of group 2 before and after the H.pylori treatment was 21.34 ± 2.40 ng/L and 22.24 ± 2.10 ng/L(P = 0.785).The plasma ghrelin levels increased substantially after treatment in group 1 but showed only minor changes in group 2.Similarly,the gastric ghrelin mRNA expression in group 1 before treatment was 2.84 ± 0.08.After treatment,the level was 3.11 ± 0.65,which was significantly different(P = 0.023).The gastric ghrelin mRNA expression in group 2 did not change significantly during the treatment(2.82 ± 0.44 vs 2.79 ± 0.31,P = 0.875).The plasma ghrelin and gastric ghrelin mRNA levels in group 1 increased substantially after the treatment but did not do so in group 2.In addition,the body mass index the two groups did not differ significantly 2 mo before and after the H.pylori treatment.CONCLUSION:H.pylori eradication increases the plasma and tissue ghrelin levels in children with H.pylori-associated functional dyspepsia.

Hydrogen bonding-induced oxygen clusters and long-lived room temperature phosphorescence from amorphous polyols

Developing non-conjugated luminescent polymers(NCLPs)with fluorescence and long-lived roomtemperature phosphorescence is of great significance for revealing the essence of NCLPs luminescence,which has gradually attracted the attention of researchers in recent years.Herein,polymethylol(PMO)and poly(3-butene-1,2-diol)(PBD)with polyhydroxy structures were prepared and their luminescence behaviors were investigated to reveal the clusteroluminescence(CL)mechanism.Compared with polyvinyl alcohol with non-luminescent behavior,PMO and PBD exhibit cyan-blue fluorescence with quantum yields of ca.12%and green room-temperature phosphorescence with lifetimes of ca.89 ms in the solid state.Both fluorescence and phosphorescence exhibit typical excitation-dependent CL behavior.Experimental and theoretical analyses show that the strong hydrogen-bonding interaction of PMO and PBD greatly promotes the formation of oxygen clusters and the through-space n-n interaction of oxygen atoms,enabling fluorescence and phosphorescence emission.Our results have enormous implications for understanding the CL mechanism of NCLPs and provide a new polymer design strategy for the rational design of novel NCLPs materials.

Manipulation of clusteroluminescence in carbonyl-based aliphatic polymers

Clusteroluminogens(CLgens),nonconjugated structures with visible luminescence at the clustering state,have recently received remarkable attention due to their great theoretical significance and practical values.In carbonyl-based aliphatic polymers,(n,π*)transition of carbonyl groups and the through-space interactions have been demonstrated to play an important role in their clusteroluminescence(CL)properties,but it is still a big challenge to manipulate their CL at the molecular level.In this work,six nonconjugated carbonyl-based polymers with different heteroatoms and steric hindrances were synthesized,and their photophysical properties were systematically studied.These polymers all showed CL but with different emission efficiency and wavelength.Experimental and theoretical studies indicated that the CL properties could be manipulated by changing the electronic structures of carbonyl groups and the rigidity of polymer chains.This work not only gains further insights into the CL mechanism but also provides reliable strategies to design and manipulate non-conjugated luminescent materials.

Clusteroluminescence:A gauge of molecular interaction

Clusteroluminescence(CL)materials,as an emerging class of luminescent materials with unique photophysical properties,have received increasing attention owing to their great theoretical significance and potential for biological applications.Although much progress has been made in the design,synthesis and application of CL materials,there is still a big challenge in the emission mechanism.So far,throughspace interaction has been proposed as the preliminary mechanism of the corresponding clusterizationtriggered emission(CTE)effect,but a systematic theory is still needed.This review summarizes the current mechanistic understanding of CL materials including organic/inorganic small molecules,and polymers with/without isolated aromatic structures.In addition,some strategies to achieve high quantum yield,adjustable emission color,and persistent room temperature phosphorescence in CL materials are also summarized.At last,a perspective of the mechanism and application of CL materials are demonstrated,which inspire the researchers working on the development of new kinds of functional materials.

Interruption Characteristics of High-speed Switches in 500 kV Fault Current Limiter with High Coupled Split Reactance

A 500 kV high-voltage AC fault current limiter(FCL)based on a high coupled split reactor(HCSR)is pro-posed by the National key R&D project team.Low impedance under normal conditions and high impedance under short-circuit conditions are accomplished by the cooperation of HCSR and high-speed switches.High-speed switches play an important role in current limiting processes,thus interruption characteristics of the high-speed switch in the 500 kV FCL are studied in this paper.The simulation model of the FCL and the external equivalent power grid are established.The short-circuit current and recovery voltage characteristics of the high-speed switch in FCL are simulated.The results show that maximum DC component of the short-circuit current of the high-speed switch reaches 91%,the maximum peak value is 118 kA,and the longest arcing time is 14.8 ms.There is a discontinuity in the curve of the short-circuit current peak and arcing time as a function of the short-circuit occurrence time;the peak recovery voltage of a single break of the high-speed switch has a maximum value of 87.5 kV under a three-phase ungrounded short-circuit condition,and the rate of rise of recovery voltage is o.22 kV/s.The recovery voltage peak shows a period change with the short-circuit occurrence time,and the period is 10 ms.The effects of the shunt capacitor value and short-circuit ground resistance on the recovery voltage of high-speed switching are also studied.The research can be used for reference by R&D personnel and testersof500kVFCLs.Index Terms-Fault current limiter(FCL),high coupled split reactor(HCSR),high-speed switch,interruption characteristics,short circuit current.

miRNA-181 regulates embryo implantation in mice through targeting leukemia inhibitory factor

Embryo implantation is a crucial step in mammalian reproduction.However,little is known regarding the physiological roles of microRNAs in the regulation of embryo implantation.Here we show that a minimum uterine expression of miR-181 is essential for the onset of embryo implantation.Both transient and prolonged transgenic expression of miR-181 led to impaired implantation,which can be rescued by exogenous administration of leukemia inhibitory factor(LIF).Mechanistically,miR-181 is able to directly target LIF and downregulate LIF expression,thereby inhibiting embryo implantation.We also show that miR-181 expression is regu-lated by the transcriptional factor Emx2,and the Emx2–miR-181 axis plays an importantrole in regulating embryo implantation.Taken together,these results reveal a novel function of miR-181 in embryo implantation through the regulation of LIF,and also indicate a potential link between miR-181 dysregulation and human embryo implantation defects.