Effect of heat-activated nickel-titanium arch wire for orthodontic treatment on local tissue inflammation and bone destruction

Objective:To study the effect of heat-activated nickel-titanium arch wire for orthodontic treatment on local tissue inflammation and bone destruction.Methods:Patients who received orthodontic treatment with nickel-titanium arch wire in Hancheng People's Hospital between March 2012 and October 2017 were retrospectively studied, and according to the nickel-titanium arch wire materials in history data, the patients were divided into the experimental group who used heat-activated nickel-titanium arch wire and the control group who used common nickel-titanium arch wire. 1 week after treatment, the gingival crevicular fluid was collected to determine the contents of inflammatory cytokines as well as the mRNA expression of osteoblast markers and osteoclast markers.Results: 1 week after treatment, IL-1α, IL-1β, sTREM1 and HMGB1 contents as well as RANKL, 5-LOX, LTB4, TRACP5b and ODF mRNA expression in gingival crevicular fluid of experimental group were significantly lower than those of control group whereas OPG, Wnt3a, Runx2, OC, ALP and OCIF mRNA expression were significantly higher than those of control group.Conclusion: Heat-activated nickel-titanium arch wire for orthodontic treatment can be more effective than common nickel-titanium arch wire to reduce the local tissue inflammation and inhibit the bone destruction.

Adsorption of Rhodamine B from Aqueous Solution onto Heat-Activated Sepiolite

The heat-activated sepiolite,which was prepared using sepiolite by thermal treatment at different temperatures,was used as an absorbent for the removal of rhodamine B（RhB） from aqueous solutions.The structure and morphology of the as-prepared samples were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM） techniques,respectively.The adsorption capacity of RhB onto the heat-activated sepiolite has been examined with pH,adsorbent dosage,contact time,initial dye concentration,and temperature.Kinetic studies showed that the equilibrium was attained within 40 min,and the kinetic data were well described by the pseudo-second-order kinetic model.Besides,the experimental data（R 2 〉0.999） fitted the Freundlich model better than the Langmuir model.The as-prepared sample showed higher adsorption capacity（8.33 mg/g） for the removal of RhB than that of sepiolite,which could be attributed to more adsorption sites caused by appropriate heat treatment.The adsorbent can be well regenerated by calcination at 400 ℃ for 2 h and regenerated sepiolite did not exhibited significant loss of adsorption activity after five recycles.

Oscillation of S5 helix under different temperatures in determination of the open probability of TRPV1 channel

Transient receptor potential vanilloid subtype 1 (TRPV1) is a polymodel sensory receptor and can be activated by moderate temperature (≥ 43 ℃). Though extensive researches on the heat-activation mechanism revealed some key elements that participate in the heat-sensation pathway, the detailed thermal-gating mechanism of TRPV1 is still unclear. We investigate the heat-activation process of TRPV1 channel using the molecular dynamics simulation method at different temperatures. It is found that the favored state of the supposed upper gate of TRPV1 cannot form constriction to ion permeation. Oscillation of S5 helix originated from thermal fluctuation and forming/breaking of two key hydrogen bonds can transmit to S6 helix through the hydrophobic contact between S5 and S6 helix. We propose that this is the pathway from heat sensor of TRPV1 to the opening of the lower gate. The heat-activation mechanism of TRPV1 presented in this work can help further functional study of TRPV1 channel.