ABSTRACT
<p><b>OBJECTIVE</b>To study the callus induction and plant regeneration of Ixeridium sonchifolium.</p><p><b>METHOD</b>By using the orthogonal experiment design, the medium for callus induction and plant regeneration was optimized.</p><p><b>RESULT</b>The optimal medium for callus induction was MS + 2, 4-D 1.5 mg x L(-1) +6-BA 1.5 mg x L(-1) +NAA 1.0 mg x L(-1) + IBA 1.5 mg x L(-1) + KT1.5 mg x L(-1), the optimal medium for inducing adventitious bud was MS +2, 4-D 0.2 mg x L(-1) +6-BA 0.5 mg x L(-1) + NAA 0.5 mg x L(-1) + IBA 0.5 mg x L(-1) + KT 0.5 mg x L(-1). Plantlets were rooted on 1/4MS medium supplemented with different concentrations of IBA, and high rooting and survival was achieved when the IBA concentration was 0.1 mg L(-1).</p><p><b>CONCLUSION</b>An efficient system for plant regeneration of I. sonchifolium was established.</p>
Subject(s)
Asteraceae , Physiology , Plants, Medicinal , Physiology , Regeneration , Physiology , Tissue Culture Techniques , MethodsABSTRACT
<p><b>OBJECTIVE</b>To establish a spectrophotometric determination method of bromine in the air of workplace.</p><p><b>METHODS</b>Bromine in the air of workplace was absorbed by methyl orange solution, then determined by spectrophotometry.</p><p><b>RESULTS</b>The range of the determination was 0.2 to 2.8 microg/ml, the linear equation was Y=0.0427X-0.0092, r=0.9996. The detection limit was 0.2 microg/ml. The minimum detectable concentration was 0.27 mg/m(3) for 7.5 L air sample. The relative standard deviations covered the range of 1.1% approximately 3.7%. The recovery rate was in the range of 93.6% to 97.2%. The sampling efficiency ranged from 93.5% to 100.0%.</p><p><b>CONCLUSION</b>The method is available for the determination of bromine in the air of workplace.</p>
Subject(s)
Air , Air Pollutants, Occupational , Bromine , Spectrophotometry , Methods , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>This study aimed at investigating bio-tribological property of titanium opposite to teeth as a base of clinical application.</p><p><b>METHODS</b>Under a modified fretting machine, wear tests on human natural teeth were carried out in artificial saliva conditions against to pure titanium. The dynamic frictional process and wear mechanisms were investigated by means of Nene-2, MVK-H12, TALYSURF6, OM, LSM, SEM, EDX.</p><p><b>RESULTS</b>The coefficient of friction exhibited a variation pattern of longs. The wear mechanism of natural tooth was detected as micro-cut and denaturation of dental texture and the wear depth of Ti/teeth was 20.33 + 2.86 microm, the wear depth of Ti/Ti being 38.00 + 5.88 microm (P < 0.05).</p><p><b>CONCLUSIONS</b>The natural tooth has a good tribological behavior, matching the friction behavior of pure titanium. Over occlusal force during masticate process and para-function should be avoided. When we chose dental materials, wear resistance should be taken into account.</p>
Subject(s)
Humans , Dental Materials , Dental Prosthesis , Friction , TitaniumABSTRACT
<p><b>OBJECTIVE</b>To study the biomarkers of styrene and to provide theoretical basis for bio-monitoring of styrene.</p><p><b>METHODS</b>Urinary mandalic acid (MA), phenylglyoxalic acid (PGA) and mercapturic acid (MUA) of styrene were examined by high performance liquid chromatography (HPLC).</p><p><b>RESULTS</b>The correlation regression equations between exposure dose and MA, PGA and MUA level in morning urinary samples were: ŷ = 2.58x + 70.82; ŷ = 1.66x + 37.42; ŷ = 0.05x + 0.55 respectively. The correlation regression equations between exposure dose and MA, PGA and MUA level in post-shift urinary samples were: ŷ = 1.85x + 89.02; ŷ = 1.33x + 4.32; ŷ = 0.04x + 0.68 respectively. All showed close dose-response relationship.</p><p><b>CONCLUSIONS</b>The level of MA, PGA and MUA in morning or post-shift urinary samples may be used as bio-monitoring indexes of styrene.</p>