Type Ⅰ and type Ⅱ Helicobacter pylori infection status and their impact on gastrin and pepsinogen level in a gastric cancer prevalent area

BACKGROUND Type I Helicobacter pylori(H.pylori)infection causes severe gastric inflammation and is a predisposing factor for gastric carcinogenesis.However,its infection status in stepwise gastric disease progression in this gastric cancer prevalent area has not been evaluated;it is also not known its impact on commonly used epidemiological gastric cancer risk markers such as gastrin-17(G-17)and pepsinogens(PGs)during clinical practice.AIM To explore the prevalence of type I and type II H.pylori infection status and their impact on G-17 and PG levels in clinical practice.METHODS Thirty-five hundred and seventy-two hospital admitted patients with upper gastrointestinal symptoms were examined,and 523 patients were enrolled in this study.H.pylori infection was confirmed by both 13C-urea breath test and serological assay.Patients were divided into non-atrophic gastritis(NAG),nonatrophic gastritis with erosion(NAGE),chronic atrophic gastritis(CAG),peptic ulcers(PU)and gastric cancer(GC)groups.Their serological G-17,PG I and PG II values and PG I/PG II ratio were also measured.RESULTS A total H.pylori infection rate of 3572 examined patients was 75.9%,the infection rate of 523 enrolled patients was 76.9%,among which type I H.pylori infection accounted for 72.4%(291/402)and type II was 27.6%;88.4%of GC patients were H.pylori positive,and 84.2%of them were type I infection,only 11.6%of GC patients were H.pylori negative.Infection rates of type I H.pylori in NAG,NAGE,CAG,PU and GC groups were 67.9%,62.7%,79.7%,77.6%and 84.2%,respectively.H.pylori infection resulted in significantly higher G-17 and PG II values and decreased PG I/PG II ratio.Both types of H.pylori induced higher G-17 level,but type I strain infection resulted in an increased PG II level and decreased PG I/PG II ratio in NAG,NAGE and CAG groups over uninfected controls.Overall PG I levels showed no difference among all disease groups and in the presence or absence of H.pylori;in stratified analysis,its level was increased in GC and PU patients in H.pylori and type I H.pylori-positive groups.CONCLUSION Type I H.pylori infection is the major form of infection in this geographic region,and a very low percentage(11.6%)of GC patients are not infected by H.pylori.Both types of H.pylori induce an increase in G-17 level,while type I H.pylori is the major strain that affects PG I and PG IIs level and PG I/PG II ratio in stepwise chronic gastric disease.The data provide insights into H.pylori infection status and indicate the necessity and urgency for bacteria eradication and disease prevention in clinical practice.

Mechanism of ferrite nucleation induced by Y_(2)O_(2)S inclusion in low carbon steel

To reveal the mechanism of ferrite nucleation induced by Y_(2)O_(2)S inclusion in steel,the work of adhesion,interfacial energy,structure stability and electronic properties of Fe(111)/YY_(2)O_(2)S(001)interfaces with various terminations were first investigated using the first-principles calculations.Secondly,the steels with and without yttrium were prepared,while the rare earth yttrium-based inclusions in low carbon steel were characterized using an electron probe micro-analyzer,and the grain size of steel was analyzed using a scanning electron microscope with electron backscattered diffraction.The results show that the bonding strength of Fe/Y_(2)O_(2)S interfaces with S-and Y-terminations is stronger than that of the interface with O-terminations.The Fe-hcp-S interfaces with S-termination have the highest work of adhesion(4.01 J/m2)and the lowest interface distance(1.323A).The Fe-hcp-S interface exhibits the highest stability,and its interfacial bonding force is mainly attributed to the strong hybridization of Fe-3d and S-2p orbitals in the energy range of-7.5-0 eV.Moreover,the interfacial energy of Fe-hcp-S is substantially lower than those of the ferrite(s)/Fe(L)interface and the ferrite-austenite interface,suggesting that Y_(2)O_(2)S inclusions in steel can efficiently promote ferrite nucleation.The experimental observations demonstrate that the ferrite grain size of steel containing 0.03 wt.% Y is much more refined than that of the steel without yttrium,and the average grain size of steel with and without Y is 102 and 258μm,respectively.This indicates that the results of our calculations match with experimental findings.

Effect of electropulsing treatment on solidification behavior of spring steels in a continuous casting mold simulator

An electropulsing-assisted mold simulator technique was developed to investigate the effects of a pulsed electric voltage on the quality of spring steels during continuous casting by analyzing the mold flux film,shell surface profile,shell micro-structure and inclusion distributions.The results revealed significantly increased crystallization fraction of the mold flux film from 61.2%to 75.3%and finer crystalline phase morphology in the case of electropulsing treatment.The surface of the initially solidified shell could be effectively healed,resulting in smoother shell surface profiles with higher pulsed voltage from 0 to 30V.Furthermore,an increase in the pulsed voltage from 0 to 30V resulted in finer dendritic structures during solidification with decreasing secondary dendrite arm spacing from the values of 17.6-32.2 to 9.7-15.0μm in the direction of shell side toward melt side.In addition,an area scan analysis of inclusions in the as-cast spring steel samples showed that the number of MnS inclusions in the size range of 2.0-4.0μm gradually decreased from 836 to 114 and the number of Al2O3 inclusions in the same size range decreased from 144 to 39,as the voltage increased from 0 to 30V.