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Objective To study the effects of mechanical load on in vivo degradation performance of high-purity magnesium (HP Mg, 99.99 wt.%) quantitatively. Methods Cylindrical Mg specimens, with a 2 mm diameter and a 14 mm length, were mounted in polyetheretherketone (PEEK) rings to bear compressive stresses ［（6.2±0.6） MPa］, tensile stresses ［（4.6±0.1） MPa］ or no stress (as control). The specimens under different stress states were implanted subcutaneously in dorsal abdominal regions of SD rats for 4 weeks. The mass loss, residual volume and surface morphology of the specimens and staining of surrounding soft tissues were used to analyze the degradation rate of HP Mg. Results Specimens and rings were completely encapsulated by membranous tissues after implantation for 4 weeks. No significant differences in the degradation rates were noted between specimens bearing stress and the control. The corrosion layers of specimens under each stress state were uniform. Conclusions The compressive and tensile stresses (4-6 MPa) could not affect significantly HP Mg degradation performance in vivo. The research findings provide theoretical references for the design and clinical application of Mg-based degradable implants.
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Objective To understand the cue-induced craving, physiological reactions to heroin-related cues, and to explore the factors that impact the cue-induced craving. Methods 369 abstinent heroin addicts were exposed to videotapes of heroin using and simulacrum after the self relaxation. The craving, abstinent symp-toms were measured before and after cue exposures. The physiological reactions were measured by multi-biofeed-back instrument before, during, and after cue exposure. BIS-Ⅱ questionnaire was used to collect information about their impulsive characteristic. Results After cue exposure, the self-reports scores of craving (t=11.24, P< 0.01), physiological index including heart rate((76.6±11.3) beats/min, F=19.23), skin conduct ((7.48± 4.25)μs, F=53.99), pupil size (t=11.73) had significant change in heroin addicts (P<0.01). Logistic regres-sion results showed that the scores of BIS-Ⅱ were related to cue-reduced craving (P=0.001,95% CI: 1.015～1. 065). Conclusions Exposure to drug-related cues can induces craving and physiological reactions in long term abstinence heroin addicts. High impulsive characteristic is a risk factor to induce drug-related craving. The inter-vention strategies should consider the impulsive characteristic and make a comprehensive intervention program to prevent relapse.
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Objective:To understand whether or not biofeedback therapy(BT)and cue- exposure therapy(CET)could decrease craving and heroin-related cue reactivity in abstinent heroin dependents.Methods:Adopting stratified sampling means,60 abstinent heroin dependents whose craving increased after cue exposed,were allocated to experiment group(n=36)and control group(n=24).The control group dependents received assistance and education.Beside the assistance and education,the experiment group also received 12 times combination therapies of BT and CET.Results:After therapies,the experiment group dependents' craving,EMG and skin conductance(SC)were all decreased compared with control group before cue exposures and after cue exposures[Before cue exposures,the indexes were:craving(3.06±7.26)mm vs.(22.32±20.26)mm;EMG(8.52±4.23)μV vs.(12.06±5.17)μV,SC(2.14±1.43)μS vs.(4.61±2.24)μS.After cue exposures the indexes were:craving(6.97±10.30)mm vs.(33.14±25.40)mm,MEG(8.72±4.31)μV vs.(14.79±5.86)μV,SC(2.15±1.33)μS vs.(4.49±2.59)μS;Ps≤0.01.Conclusion:The combination of biofeedback therapy and cue-exposure therapy could decrease the dependents' craving and cue reactivity sensitivity.