The endosopic imaging was simulated using SketchUp software, and the preliminary definitions of the visual relative quantity space (VRQS), visual absolute quantity space (VAQS), and visual space scale unit (length) VSSU (VSUL) were made to discuss characters of them; With the elevation angle or the distance of the endoscope entering the nasal cavity changed, the law and the cause of the spatial directions in the visual field of the endoscope were analyzed by the theory of VRQS, VAQS, and VSSU (VSUL). The perspective law in the 0° VRQS is: With the distance to the visual point nearer, the length of the VSSU in the view of the endoscope is longer. If the distance of the endoscope entering the model is increased only, the position of the spatial direction in the view of the endoscope shows the repeatable and substituted characteristics. If the elevation angle of the endoscope is changed only, the spatial directions in the view are changed. The change of the spatial directions in the view could be explained by the theory of VRQS, VAQS, and VSSU (VSUL). The change of the elevation angle of the endoscope can caused the change of the spatial directions in the view. The spatial directions in the view of the endoscope have the repeatable and substituted characteristics; the theory of VRQS, VAQS, and VSSU (VSUL) can completely explained the changes of the spatial directions, which provides a good basis for the operations and the further research.

Objective To observe the characteristics of the spatial vertical direction in the view of 0? endoscope with the elevation angle(between the endoscope and nasal bottom)unchanged,and to provide the basis for operations.Methods The ideal model of nasal cavity was designed and observed with the 0? rod-lens telescope.Space of the model in the visual field of endoscope with 30? or 45? elevation angle produced was simulated by SketchUp software.Then ten lines(perpendicular to the horizontal planes,distributed in different plane and in the same side of the visual vertical line)were drawn randomly and named as Ln(n=1-10)respectively.A point was randomly selected and a vertical line was drawn and assigned as b line.The position of b line in the visual view of endoscope with a 30? elevation angle was named as A1B1.The relationship of positions of Ln with A1B1 were observed when the distances of endoscope entering the model were changed and the endoscope was moved parallelly.When the point A1 was on the b line in visual view of endoscope with 45? elevation angle,the position of b line was named for A1B2.The relationship of positions of Ln with A1B2 were observed when the distances of endoscope entering the model were changed and the endoscope was moved parallelly.The position of A1B1 was compared with A1B2.Results When the distances of endoscope entering the model were changed and the endoscope was moved parallelly,the superposition of Ln with A1B1 and A1B2 could be observed in visual view with 30? and 45? endoscopic elevation angle.The positions of A1B1 and A1B2 were not in superimposition.Conclusion The spatial vertical directions in the view of the endoscope are correlated with the elevation angle but not correlated with the distance of endoscope entering the model and parallel movements of the endoscope.This finding may be helpful for the endoscopic operations.

Benign Paroxysmal Positional Vertigo ; complications ; Humans ; Otologic Surgical Procedures ; adverse effects

Bone marrow mesenchymal stem cells (BMSCs) is a kind of multipotent adult stem cells,which is one of the most important seed sources of tissue engineering.Microgravity has inhibitory effects on osteogenic differentiation of BMSCs,which will cause bone mass reduction and changes of bone micro-structure that finally lead to osteoporosis.This process is regulated by multiple signaling pathways such as mitogen-activated protein kinase (MAPK) pathway,Notch pathway and Wnt/β-catenin pathway which co-regulated BMSCs osteogenic differentiation under microgravity.Studying the effects of microgravity on BMSCs into osteogenic differentiation can clarify the mechanism of bone loss,put forward new targets for the treatment of diseases and provide a useful reference for the development of China's space industry.

OBJECTIVE To study the benefits of applying digital visible models for endoscopic nasal surgery.METHODS CT data sets of 16 patients were segmented to create digital visible models by using AutoCAD(computer aided design),MOI (Moment of Inspiration) and SketchUp software package.Standard digital available data sets for clinical tasks such as surgical simulation and surgical planning.The digital visible models and the intra-and postoperative corresponding visions were compared. RESULTS The 3D structure model of nasal cavity, sinuses and their adjacent structures for endoscopic nasal surgery were successfully reconstructed.The models allowed the user to interact with the data and manipulate them(in the view of X-ray,looking around inside the model).The model can be observed during operation,provided accurate morphological data for surgery guidance plan.CONCLUSION The method creating digital visible models using AutoCAD,MOI and SketchUp software package is simple and feasible.The digital visible models are suitable for clinical use as well as for education of endoscopic nasal surgery.The benefit of this technology was confirmed by clinicians.

This paper designs a kind of electric field generator based on high-frequency waveform generator MAX038 according to the need of the myocardial tissue engineering research.The amplitude,pulse width and frequency of the signal producing by the generator can be adjusted.Characterized with high precise and wide frequency scope,this generator can produce triangle,square and sine waveforms and pulse etc.

BACKGROUND: Minimally invasive percutaneous pedicle screw fixation possesses the advantages of less blood loss, less muscle and soft tissue dissection, and rapid recovery; however, accuracy of the screw positioning is the key to be successful.OBJECTIVE: To explore the application value of self-designed spinal localizer in the screw positioning for minimally invasive percutaneous pedicle screw fixation.METHODS: 428 patients with thoracolumber disorders were subjected to minimally invasive percutaneous pedicle screw fixation at the First Affiliated Hospital of University of South China, from March 2009 to March 2015, and randomly underwent the preoperative screw positioning by self-designed spinal localizer or one of traditional localizing methods (iliac crest, ribs, symptomatic vertebral appearance, skin marker, Kirscher wire, puncture needle localizations). The location accuracy, positioning time and radiographic times were compared among methods.RESULTS AND CONCLUSION: (1) Compared with the traditional localization methods, the self-designed spinal localizer was superior in accurate rate (P < 0.05), cost less positioning time (P < 0.05) and received less radiation (P < 0.05). (2) To conclude, the self-designed localizer exhibits a certain application value, which is an ideal method in preoperative localization for minimally invasive percutaneous pedicle screw fixation.

OBJECTIVE To know the principles of the transformations of the spatial directions in the view of the 0~ sinus endoscope and to simulate the space in endoscope using SkechUp software. METHODS The ideal model of the nasal cavity was designed and observed by the 0?rod-lens telescope. The space of the model in the endoscope was simulated using SkechUp.The principles of the transformations of the spatial directions were observed,which consisted of the lateral horizontal line (Lhn,n=0-6),the lateral vertical line (Lvn,n=0-9),the top horizontal line (Thn, n=0-9) and the lateral angle line (LAL).The location of the horizon was observed.RESULTS If the elevation angle (between the endoscope and bottom of nasal cavity) of the endoscope entering the model was unchanged and the distance of the endoscope entering the model was increased gradually,the positions of Lhn,Lvn and Thn in the visual field of the endoscope were replaced by Lh (n+1),Lv (n+1) and Th (n+1) respectively.The positions of Lhn,Lvn and Thn had repeatable characteristics.One horizontal plane in the space can become a horizon in the view and the location of the horizon in the view was invariable.If the distance of the endoscope entering the model was unchanged,the endoscope was moved to produce15?,30?,45?,60?elevation angle gradually,the positions of LAL (15?,30?,45?,60?) had the symmetry and repetition and the position of the horizon in the view was variable.CONCLUSION The directions of Lh and Lv and the locations of the horizon in the view of the 0?endoscope are correlative with the elevation angle of the endoscope,not pertinent to the distance of the endoscope coming into the nasal cavity.The directions of the space in the visual field of the endoscope have the symmetry and repeatable characteristics.Simulating the space in the visual field of the endoscope using SkechUp software provides the bases for the operation.

BACKGROUND: T-type or linear type external fixator is applied in transcervical fracture in the elderly. Because its fixing force is weak, so it is difficult to avoid the aggravation of complication due to long term lay up in severe osteoporosis. Based on this reason,percutaneous penetrating arch tri-claw external fixator is designed to treat elderly transcervical fracture with strong fixing force for the realization of early restoration to the active status before injury to reduce complication.OBJECTIVE:To design pereutaneous penetrating arch tri-claw external fixator for the treatment of elderly transcervical fracture for the investigation of its feasibility.DESIGN: A self-controlled study by employing patients as subjects.SETTING: Department of orthopedic surgery of the first affiliated hospital of a universityPARTICIPANTS: Thirty-one cases of elderly transcervical fracture including 18 males and 13 females aged between 71 and 86 years old with an average age of 79 years were admitted by the Department of Orthopedics of the First Affiliated Hospital of Nanhua University between December 2002 and June 2004.METHODS: Percutaneous penetrating arch tri-claw external fixator was applied in the treatment of 31 cases with elderly transcervical fracture for the observation of its clinical effects, and the force-bearing situation and stability of the external fixator during application were analyzed by theoretical mechanics.MAIN OUTCOME MEASURES: ① The functional effects of percutaneous penetrating arch tri-claw external fixator applied in the therapy of transcervical fracture(sub-femoral head type,transcervical type and femoral basilar type); 2② The force-bearing situation and the stability of the fixing point on the fixator; ③ The restoration of activity in hip joint and fracture union time RESULTS: ① Patients could sit and stand immediately after the applicationof the fixator, and its fixing reinforce was analyzed by theoretic mechanics during standing(the force on upper fixing point A, B or C was 1/22, 1/2 or 1/2 of the lower fixing point) . The unidirectional flexion and extension activity of the hip joint overcame hip-inversion and rotational disposition at the distal end of the fracture. The hip-joint axial compression board caused compact embedment and insertion of the fracture end and vertical crush to simulate fracture union by stability and compressive strain. ② The stability of percutaneous penetrating arch tri-claw external fixator: No disposition was found during the application except rotational disposition during activity in sub-femoral head type fracture. The fixation was stable, the operative trauma was less,and the operation was simple with good accommodation. No complication was found due to long-term lay up and no re-disposition due to the loosening of the external fixator was found. ③ The hip-joint flexion-extension function was restored within 7 days averagely and fracture healing time was about 2 to 3 months, average of 2.4 months.CONCLUSION: No re-injury is found dter the application of percutaneous penetrating arch tri-claw external fixator, which has small force bearing at upper fixing point with strong stability. There is strain stimulation on the cross section of the fracture to promote fracture healing. The articular function status before injury could be restored at early stage.

BACKGROUND: Seed cell exerting its function is required to depend on the extracellular matrix in tissue engineering, so that biocompatible material is important to be selected. OBJECTIVE: To prepare a novel composite scaffolds of chitosan/collagen/nano-hydroxyapatite (HA-CS/Col/nHAP) and to optimize the technology of tissue engineered-stents according to the circumstances of cell adhesion.METHODS: Chitosan was modified by hyaluronate acid. The structure was observed by differential scanning calorimetry and the Fourier transformed infrared spectroscopy. Three composites of HA-CS/Col/nHAP according to different ratio of chitosan and collagen solution (1: 2; 1: 1 and 2: 1) were prepared. The composite scaffolds were co-cultured with osteoblast MC3T3-E1, and the proliferation and cell growth curve were measured by CCK-8 method. RESULTS AND CONCLUSION: Hyaluronic acid and chitosan were crosslinked with amide linkage. Pore size was on the range from 50 μm to 250 μm. Porosity was increased with increased collagen level and elastic modulus, but density was reduced. Increased collagen content was beneficial for cell adhesion and proliferation on stent in the primary phase of cell co-culture. However, from day 10, no significant difference was determined among three samples. At the beginning of cell culture, cells adhered to the airspace insides the composite scaffolds. In the following days, cells grew in a colony manner, and cell-cell junction could be easily observed. These indicate that HA-CS/Col /nHAP composite scaffolds can improve the adhesion and proliferation of osteoblast. The ratio of chitosan to collagen volume at 1: 1 was optimal.