Effects of Tween 80 and pH on mycelial pellets and exopolysaccharide production in liquid culture of a medicinal fungus.

This study investigated the effects of surfactant additives and medium pH on mycelial morphology and exopolysaccharide (EPS) production in liquid culture of a valuable medicinal fungus Cordyceps sinensis Cs-HK1. In the medium containing 20 g l⁻¹ glucose and 6 g l⁻¹ peptone as the sole nitrogen source, the Cs-HK1 fungal mycelia formed smooth and spherical pellets about 1.8-mm mean diameter. The mycelial pellets became less uniform at pH (4.0-5.0) lower than the optimum (pH 6.0) or turned to filamentous form at higher pH (8-9). Surfactants added to the medium inhibited pellet formation, resulting in smaller and looser pellets. Tween 80 exhibited a remarkable promoting effect on EPS production, increasing the EPS yield more than twofold at 1.5% (w/v), which was most probably attributed to the stimulation of EPS biosynthesis and release from the fungal cells by Tween 80.

Effect of maxillary expansion on orthodontics.

OBJECTIVE: To explore the effect of maxillary expansion on orthodontics. METHODS: Eight beagle dogs were randomly divided into two groups, with 4 dogs in each group. Dogs in group 1 were executed immediately and received the direct physical measurement. The magnetic expansion appliance was used in group 2 for the maxillary expansion. After the expansion, the model was taken again and they were executed after cone beam CT (CBCT) scanning. The model measurement method was adopted in group 1 to measure the dental measurement indicators and width of base bone arch. The CBCT measurement method was employed to measure the above dental indicators and bone indicators. The difference in the indicators measured by different methods was compared and analyzed. RESULTS: Before the expansion, there was no significant difference in the bone measurement indicators between the CBCT measurement method and direct physical measurement method. After the expansion, there was no significant difference in indicators between the CBCT measurement method and direct physical measurement. But there was significant difference among the model measurement method, CBCT measurement method and direct physical measurement method. There was the significant difference in the dental indicators between the CBCT measurement method and model measurement, as well as the bone indicators of posterior marginal spacing of greater palatine foramen, posterior marginal spacing of incisive foramen, width of base bone arch and spacing of implant anchorage. CONCLUSIONS: There is no significant difference between the effect of CBCT measurement method and direct physical measurement method, but CBCT is significantly better than the model measurement.

Polyethylenimine coated bacterial cellulose nanofiber membrane and application as adsorbent and catalyst.

Bacterial cellulose (BC) nanofiber membranes were simply aminalized by a flush-coating and post-crosslinking method. Firstly, wet BC membranes were flushed through by an aqueous solution of polyethylenimine (PEI) and glycerol diglycidyl ether (GDE) under vacuum suction, then further heated up to 70 °C to crosslink the resultant coating on the surface of the nanofibers. The PEI coated bacterial cellulose (BC@PEI) nanofiber membrane presented excellent adsorption performance for Cu(2+) and Pb(2+) ions from aqueous solutions. Desorption of these ions was achieved using ethylene diamine tetraacetic acid treatment. This cycle of adsorption and desorption was repeated for several times with good remain adsorption performance (over 90%). Furthermore, the adsorbed Cu(2+) ions can be reduced to copper nanoparticles, and showed excellent catalytic performance for methylene blue reduction in aqueous solution. The catalytic performance can remained after several times of usage.

[Initial stress in the periodontal membrane of maxillary first molar with different alveolar bone height by intrusion: 3-dimensional finite element analysis].

PURPOSE: To establish the 3-D finite element models of maxillary first molar, and calculate the stress magnitude and distribution within the PDL of maxillary first molar when loaded with intrusion force. METHODS: Date from CT scanning image of the maxillary first molar was used to establish the 3-D finite element model of maxillary first molar. By simulating the horizontal unbalanced bone resorption model sequentially, the magnitude and distribution of PDL stress at these models were calculated under intrusion force. RESULTS: The 3-D finite element models of maxillary first molar were constructed. With constant decrease of alveolar bone height, stress of the PDL increased non-linearly. The stress in PDL changed slowly when alveolar bone height reduced from normal level to 3.5 mm, but it increased dramatically when the height of alveolar bone resorption exceeded 6.0 mm and root furcation was exposed. The high-stress concentrated in root furcation of maxillary first molar when root furcation had not been exposed, and it would be transfered to apex or one third of root length when root furcation had been exposed. CONCLUSIONS: With the sustained decrease of alveolar bone height (less than 6 mm), orthodontic force value should be reduced according to the degree of periodontal bone loss. When the alveolar bone loss reduces to more than 6 mm and the root furcation exposes completely, orthodontic force value should be reduced significantly. Supported by Natural Science Foundation of Jiangxi Province (0540091).

Homogeneous sulfation of bagasse cellulose in an ionic liquid and anticoagulation activity.

Homogeneous sulfation of bagasse cellulose (BC) with chlorosulfonic acid-dimethylformamide was accomplished in an ionic liquid 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl). The BCS products from the sulfation had degrees of substitution (DS) in the range of 0.52-2.95 and a simultaneous substitution pattern at C-6, C-2 and C-3 positions. The sulfated BCS attained significant anticoagulation activity, causing a dose-dependent prolongation of coagulation time and inhibition of FIIa and FXa activities in human plasma. The anticoagulation activity of BCS showed a positive correlation with DS, and some of the activity indexes exceeded those of heparin.

[An experimental study of the regional load deflection rate of multiloop edgewise arch wire in two dimension brackets].

OBJECTIVE: To compare the regional load deflection rate (LDR) of multiloop edgewise arch wire (MEAW) of three dimensions with coupled use of two dimension brackets in the individual interbracket span, to understand the mechanical properties of MEAW. METHODS: The MEAW arch wires of stainless steel of three dimensions, 0.41 mm x 0.56 mm, 0.43 mm x 0.64 mm and 0.46 mm x 0.64 mm, were bent into single L-loop. The study was performed with the coupled use of 0.41 mm x 0.56 mm wires with 0.46 mm x 0.64 mm bracket (A bracket) and 0.43 mm x 0.64 mm, 0.46 mm x 0.64 mm wires with 0.56 mm x 0.71 mm bracket (B bracket). The LDR of each L-loop at the individual interbracket span when loading and unloading was measured. The data were analysed by SPSS 11.0. RESULTS: Compared the regional LDR for the couple of 0.41 mm x 0.56 mm L-loop with A bracket with those for the couple of 0.43 mm x 0.64 mm L-loop with B bracket, the former showed lower value than the latter at regions between the upper central and lateral incisor, the lower central and lateral incisor, and between the lower lateral incisor and canine (P < 0.05). For the rest regions, the two couples exhibited similar value to the regional LDR (P > 0.05). The regional LDR for the couple of 0.41 mm x 0.56 mm L-loop with A bracket were lower at all regions than those for the couple of 0.46 mm x 0.64 mm L-loop with B bracket (P < 0.05) except that at the region between the lower first and second molars which showed similar value between the two couples. CONCLUSION: The coupled use of B bracket with 0.43 mm x 0.64 mm MEAW arch wire and A bracket with 0.41 mm x 0.56 mm MEAW arch wire exhibited similar mechanical properties.

[Treatment effects of magnetic Twin-block appliance for class II cases].

OBJECTIVE: To evaluate the effects of magnetic Twin-block appliance in the treatment of skeletal class II cases. METHODS: The magnetic Twin-block appliance was embedded with two pairs of neodymium-iron-boron (Nd(2)Fe(14)B) rare earth permanent magnets in the upper and lower inclined planes of Twin-block appliance. The sample comprised of 13 skeletal class II patients in the late mixed or early permanent dentition treated by magnetic Twin-block appliance. Cephalometric films were taken before and after treatment. Helix CT images of the temporomandibular joint (TMJ) in all patients were examined before treatment (T1), during treatment (4 months after appliance placement, T2), after treatment (T3) and one year after treatment (T4). RESULTS: A double contour image was detected in the superior posterior part of the condylar head on the pseudo-sagittal reconstruction plane pictures of T2 in 11 patients. The double contour image could be observed in most patients as well. This image also exhibited on the pictures of T3 in several patients. On the pictures of T2 and T3 in some patients, interruption of cortical bone and "bifurcation phenomenon" of condyles were shown. Pictures of T1 and T4 were similar and no signs of remodeling of TMJ were observed. Cephalometric analysis revealed significant changes in the maxillofacial structure after treatment. The profile of patients improved. CONCLUSIONS: Bone remodeling of condyle occurred during the magnetic Twin-block treatment in class II patients. Magnetic Twin-block appliance was effective in the treatment of the growing skeletal class II patients.

[A study of frictional resistance of archwires and ligating methods].

PURPOSE: To study the effect of 4 archwires and 2 ligating methods on the frictional resistance. METHODS: The static and dynamic friction of different combinations of 4 archwires and 6 preadjusted brackets and 2 ligating methods in the buccal segments were tested in the dry state. The friction was tested by the load cell in the LJ-500 testing machine. Orthogonal experiment design was performed in this study. The data were analysed by analysis of variance and regression analysis using the statistical analysis system. RESULTS: The smallest frictional resistance in 4 different archwires was produced by combination of 0.018 x 0.025 inch stainless rectangular wire and all preadjusted brackets. The biggest frictional resistance in 4 different archwires was produced by combination of 0.019 x 0.025 inch stainless rectangular wire and all preadjusted brackets. The static friction of combination of 0.020 inch stainless round wire and all preadjusted brackets were higher than 0.018 inch stainless round wire. The dynamic friction of combination of 0.018 inch stainless round wire and all preadjusted brackets were higher than 0.020 inch stainless round wire. Among 4 kinds of stainless wires, the ratio of dynamic to static friction of 0.018 inch round wire appeared the highest, followed by 0.018 x 0.025 inch rectangular wire, 0.020 inch round wire and 0.019 x 0.025 inch rectangular wire. Elastomeric ring ligature produced higher friction and the ratio of dynamic to static friction than stainless steel ligature. CONCLUSIONS: 0.018 inch stainless steel round wire was not suitable for sliding mechanics in this study. One should pay attention to anchorage control in using 0.019 x 0.025 inch rectangular wire. Elastomeric ring ligature was not advantageous for sliding of brackets and wires in the dry state.