ABSTRACT
As a new potential bone graft material, tissue engineered bone effectively compensates for the defects of today's bone repair materials. Meanwhile, mesoporous silica nanomaterials(MSNs) have been widely recognized due to their large specific surface area, good biocompatibility, and capability of further processing and modification. They have promising application prospects in bone tissue engineering. For the basic scientific research results that have been carried out in the early stage, the basic characteristics of mesoporous silica nano biomaterials and their application advantages, research status and development prospects in bone tissue engineering are reviewed. As for the research status, there are two aspects--as a carrier or as a component of engineering scaffolds. For the first aspect, different kinds of loaded drugs and different loading methods are reviewed. For the second, microstructure and mechanical properties of various complex scaffolds containing MSNs and the molecular and cellular behavior of seeded cells on these scaffolds are reviewed. The research of MSNs in bone cements and metal ions doped MSNs in bone tissue engineering are also included. The future development of MSNs in bone tissue engineering is also discussed.
Subject(s)
Bone and Bones , Nanoparticles , Porosity , Silicon Dioxide , Tissue EngineeringABSTRACT
Objective To explore the strategy and countermeasures of Oncomelania hupensis snail control and evaluate the effect in inside-embankment areas of lake-type schistosomiasis endemic area,for providing the effective method for controlling and interrupting the schistosomiasis transmission. Methods The data of schistosomiasis epidemic and its control and preven-tion were collected in Junshan District,Hunan Province,and the effect of snail control countermeasures were evaluated and the trend of indexes of snails was drafted in the inside-embankment areas of Junshan District,Hunan Province from 1998 to 2007. Results The area with snails in the inside embankment areas of Junshan District decreased by 98.43%,from 1496.66 hm2 in 1998 to 23.48 hm2 in 2017. The occurrence rate and average density of of living snails decreased from 20.61%and 0.45 snail/0.1 m2 in 2003 to 2.06%and 0.03 snail/0.1 m2 in 2017. The highest area with schistosome infected snails was found in 2001 and the total area was 79.36 hm2,however,no infected snails were found since 2007. The total fiscal investment for schistosomiasis pre-vention and control was 398.857 million RMB in Junshan District,including molluscicide(81.7709 million RMB)and environ-ment reform(213.5 million RMB)respectively. Conclusion The comprehensive measures,mainly including the combination of molluscicide and environment reform have gotten a significant effect in snail control and elimination in the inside-embankment areas,but the snail surveillance still need to be strengthened in the historic areas with snails.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the profile of mandibular denture polished surface in edentulous patients with different residual ridge resorption (RRR) using neutral zone record.</p><p><b>METHODS</b>Twenty randomly selected edentulous patients with different category of RRR were investigated, which were divided into three groups according to ridge resorption grade and the relationships between upper and lower jaws: group 1: Class I edentulous patients (n = 6), group 2: Class II edentulous patients (n = 7), group 3: Class III edentulous patients and crossbite jaw relationship (n = 7). All subjects were asked to perform sufficient functional movement with silicon registration material in their mouth to record the shape, which were interpreted as the ideal shape of denture polished surface. Three-dimensional laser scanner was used to record the data of the outline of the maxillary and mandibular ridge and the silicon record of the polished surface. Digital model reconstruction was then conducted on the workstation. Sagittal surface of the model in the cut-in point on first molar and first premolar was made and data of the outline of these surfaces was collected.</p><p><b>RESULTS</b>Both the buccal and the lingual polished surfaces were concave, straight or slight protuberant and inclined respectively in group 1, 2 and 3. The average angles between the horizontal and the lingual polished surface were (80.40 +/- 3.51) degrees, (90.38 +/- 2.71) degrees and (96.59 +/- 5.00) degrees respectively.</p><p><b>CONCLUSIONS</b>The polished surfaces were changed with different progress of RRR in edentulous patients. It was suggested that the degree of residual ridge resorption and the relationship between upper and lower jaws should be considered when clinicians design the polished surface of denture.</p>
Subject(s)
Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Alveolar Bone Loss , Denture Bases , Denture Design , Denture, Complete, Lower , Lasers , Microscopy, Electron, Scanning , Mouth, Edentulous , Pilot Projects , Surface PropertiesABSTRACT
<p><b>OBJECTIVE</b>To study the factors influencing the activity of fibrinolytic enzymes from earthworm and to obtain the better way to extract fibrinolytic enzymes as well as keep its optimum activity.</p><p><b>METHOD</b>75% alcohol, 0.9% NaCl and 10% saccharose was used to extract the crude fibrinolytic enzymes from earthworm, the method of urokinase gelose-fibrin plate was used to measure the activity of fibrinolytic enzymes from earthworm. and the method of 3,3'-diaminobezidine tetrahydrochloride colorimetry to was used measure the content of selenium. The method use ts of measuring the content of arsenic was silver diethyldithiocarbamate colorimetry.</p><p><b>RESULT</b>The fibrinolytin of earthworms reared with cattle soils had higher activity than that reared with garbage. The arsenic in the earthworm's body could improve the activity of earthworm's fibrinolytin. However, the selenium had litter influence on it. Among the three methods of extraction, the 75% alcohol one was the most efficient, the 0.9% NaCl was next, and the 10% saccharose was the lowest. The influence of dialysis on the activity of fibrinolytin was less than that of ultrafiltration, when the earthworm's fibrinolytin enzyme was further sublimated.</p><p><b>CONCLUSION</b>The activity of the earthworm's fibrinolytin will be increased earthworm is reared with the fitting baits and when appropriate methods, of extraction and purification are used.</p>