MICROWAVE JOINING OF ALUMINA CERAMIC AND HYDROXYLAPATITE BIOCERAMIC

Microwave joining is a rapid developmental new technique in recent years. This paper introduces a new microwave joining equipment which was made by our lab, succeeds in alumina ceramic - hydroxylapatite bioceramic join in the equipment, and analyzes the join situation of join boundary by using scanning electron microscope (SEM), this paper analyzes the mechanism of microwave joining also. (Author abstract) 4 Refs.

Long-term results of the hydroxylapatite for laryngotracheal framework reconstruction

Objective: To discuss the long-term results of the laryngotracheal (LT) reconstruction with a composites sternohyoid myocutaneous rotary door flap (RDF) and hydroxylapatite (HA) ring.Methods: Thirty-two patients suffered by LT stenosisn were treated through LT reconstruction with a composite sternohyoid myocutaneous RDF and HA ring, then we made long-term follow up. Results:Thirty of the 32 patients were successfully decannulated from 1 to 6 months postoperatively and the decannulation rate was 93%(30/32). Decannulated failed in 2 patients because of hypertrophic scar and infection in the operative region. The term of follow-up ranged from 1 to 10 years in 30 patients. patients had a stable airway and an effective voice. Conclusion: A composite sternohyoid myocutaneous RDF and HA ring is a relatively simple method with positive long-term effect for LT reconstruction.

Large scale preparation of phycobiliproteins from <i>Porphyra yezoensis</i>using co-precipitation with ammonium sulfate

The purpose of this study was to extract phyco-biliproteins (PBP) from Porphyra yezoensis using an optimized procedure and further establish a large scale process for protein production. According to our previous experiences on the extraction of PBP, salting out methods, e.g. ammonium sulfate precipitation, worked more efficiently than isoelectric precipitation, differential centrifugation or ultrafiltration. Thus, we chose ammonium sulfate to coprecipitate PBP in crude solution. After four times of precipitation followed by one time of high speed centrifugation, the maximum purity of crude phycoerythrin and phycocyanin reached 1.94 (A565/A280) and 0.85 (A615/A280), with a yield of 0.50% and 0.37%, respectively. A total of 0.94 mg phycoerythrin and 0.54 mg phycocyanin with purity of more than 3.2 were obtained from 1 g dried P. yezoensis after additional chromatography. We further scaled up the frozen dried P. yezoensis from 20 g to 400 g, with 1295 mg phycoerythrin and 593 mg phycocyanin obtained.

Battle against Aging and Folds: Benefit and Risks of the Semi-Permanent Fillers Polylactic Acid and Calcium Hydroxylapatite

Background: Semi-permanent fillers are among the most favorable fillers on the market. Through their unique mode of action and its associated lasting aesthetic effect, they take an exceptional position. Objective: To compare the two semi-permanent fillers Poly-L-Lactic Acid (PLLA) and calcium hydroxylapatite (CaHA) in reference to the aesthetic result, patient satisfaction and side effects. Methods: Studies on side effects, patient satisfaction and aesthetic results after augmentation with semi-permanent fillers were analyzed. Results: Semi-permanent fillers seem excellently suited for the augmentation of very deep wrinkles particularly in the lower half of the face. In general, high patient satisfaction can be determined with both fillers. Here, the effect from the polylactic acid can be verified for up to two years while no effect could be verified already after one year in a majority of the patients augmented with CaHA. Short-term side effects such as bleedings or erythema in the region of the augmented area have been observed in both fillers during augmentation. The incidence of nodules and granulomas seems significantly higher in augmentations with PLLA compared to CaHA. Rare side effects such as an embolization of a blood vessel caused by the implant have been described for both fillers in case reports. Conclusion: Semi-permanent fillers are superbly suited for wrinkle augmentation. Which filler is the preferred one in what case depends strongly on the individual needs of the patient and the therapist’s experience.

PURIFICATION OF MONOCLONAL ANTIBODY 3HII AGAINSTGASTRIC CANCER FOR IN VIVO USE

Monoclonal antibody (McAb) 3Hll against gastriccancer was grown in the mouse ascites system. Toacquire a clinical grade product for cancer radioimmuno-imaging was purified by two step highperformance liquid chromatography (HPLC) protocolusing protein A and high-performance hydroxylapatite(HPHT). An analysis of data reported shows the twostep HPLC method to be the best purificationprocedure. This protocol satisfies purity and immunoreactivity requirement, and provides an sample sterility,free-pyrogens, free-mycoplasma and non-specific IgGcontamination. This procedure described was capable ofgenerating large amounts of clinical grade monoclonalantibody.

The Crystal Characteristics of Enamel and Dentin by XRD Method

Crystal characteristics of tooth enamel and dentin were investigated using XRD, SEM, and EPMA methods. The results show that the mineral phase in enamel is HA and in dentin is HA and minor whitlockites. The dentin HA and the enamel HA have different crystallinity, the crystallinity of enamel HA is much higher than that of dentin HA. The average particle size of the enamel HA and dentin HA are 897 A and 309 A, respectively. The HA in enamel is regularly arranged, and in dentin the arrangement of HA is different from the enamel HA in the same section. Both the enamel and the dentin are mainly. consisted of Ca, P, O, and C, and the trace elements Mg, Sr, Al, Na, and K. The dentin contains more trace elements than the enamel. However, the incorporation of trace elements in both dentin and enamel are very limited. Other impurities such as F and Cl are less than their detection limit. The a and c values of enamel HA are 9.433 A and 6.896 A, and those of the dentin HA are 9.498 A and 6.896 A, respectively. The expansion in a value results from those the larger size of [ CO3 ]^2- group substituing for the smaller [ OH ] ^- group in the channel, and replacement of [ OH ]^ - by [ CO3 ]^2- dominates the change in cell parameter, taking into account of other trace elements.

A New Method to Prepare Hydroxylapatite Coating of Implants

A new method （ sintering method ） to prepare hydroxylapatite coating of implants was aevetoped. The coating was characterized X-ray diffraction（ XRD ） and infrared spectroscopy with a Nicolet FTIR aparatus. The adhesion strength of coating to metal substrate were measured. The bone ingrowth of coated substrate was observed and clinical application of coated implants were reported in this paper. The comparison results of sintered coating and plasma spaded coating was discussed.

Influence of Temperature on Calcium Hydroxyapatite Nanopowders

The aim of this work is to investigate the effects of thermal treatment, in the range of temperature between 80oC - 900oC, on crystallinity, morphology and particles size of calcium hydroxylapatite nanopowders (HAp). A complete study was carried out applying 31P Magic Angle Spinning NMR, X-ray diffraction, nitrogen porosimetry and Transmission Electron Microscopy techniques. HAp specimens were prepared by chemical precipitation in an aqueous solution of calcium nitrate and ammonium hydrogen phosphate. The thermal treatment performed, showed the formation of crystals whose appearance has three main morphologies and different particles size. HAp treated up to 500oC showed a set of needle-like shape crystals with a low surface area value. These crystals turned into rod-like crystals with temperature increase, along with an increase in crystallite size. At 900oC was detected a hexagonal hydroxylapatite phase. Furthermore, Dynamic Light Scattering explored a stable HAp dispersion. The isopropyl alcohol dispersion resulted stable for at least two weeks, useful to create layers of determined morphology nanoparticles.

Production of Hydroxylapatite from Biowaste, Chicken Manure by Hydrothermal Process

Hydrothermal process has been applied for effective production of Hydrogen from biowastes. In this study hydrothermal process for production of valuable Hydroxylapatitefrom chicken manure containing phosphorus was focused on. Conditions of 400?C and 26 - 27 MPa with addition of 1 mmol Ca(OH)2 were determined as the optimal by using O-phospho-DL-serine as a model compound. Afterwards, the real biowaste containing phosphorous, chicken manure was processed under the same conditions. Formation of a Hydroxylapatite;in the solid residue was confirmed from X-ray diffraction (XRD) patterns, after purification. It was found that 27.9% of P in the chicken manure was converted to Hydroxylapatite. With the use of acetic acid as a chemical purification medium, Hydroxylapatite was obtained.

MACROPHAGES IN DEGRADATION OF COLLAGEN / HYDROXYLAPATITE(CHA), BETA-TRICALCIUM PHOSPHATE CERAMICS (TCP) ARTIFICIAL BONE GRAFT AN IN VIVO STUDY

The macrophages mediated biodegradation of two biomaterials, collagen / hydroxylapatite (CHA) and beta-tricalcium phosphate ceramics (TCP), was studied in 24 male Kunming mice and 20 male C57BL / 6 mice with histopathologic, histochemical and ultrastructural observation. It was demonstrated that macrophages infiltrated after CHA, TCP were implanted. The macrophages could be differentiated from fibroblasts and the other infiltrated cells for special cellular profile and strong acid phosphatase activity. Morphologically, monocyte macrophages and infused multinuclear giant cell degraded CHA and TCP by phagocytosis and extracellular resorption. The carbonic anhydrase activity of macrophages was demonstrated by histochemical technique. It suggested that macrophages secreted H+ and accomplished the decalcification of calcium phosphate compound of CHA and TCP. We conclude that macrophages are the main mediating cells which degraded CHA and TCP intracellularly and extracellularly.

Research on the friction and wear mechanism of Poly(vinyl alcohol)/hydroxylapatite composite hydrogel

Poly(vinyl alcohol)/Hydroxylapatite(PVA/HA) composite hydrogel was prepared with poly(vinyl alcohol) and hydroxylapatite as raw materials, using the method of repeated freezing and thawing.The morphologies of PVA/HA composite hydrogel were observed by means of high-accuracy 3D profiler and scanning electron microscope(SEM).The compressive elastic modulus and the stress relaxation characteristics of PVA/HA composite hydrogel were measured using the flat-head cylinder indenter.The friction and wear tests between PVA/HA composite hydrogel and bovine knee articular cartilage were performed on the micro-tribometer.The worn morphologies of PVA/HA composite hydrogel were observed with environmental scanning electron microscope(ESEM).The results showed that PVA/HA composite hydrogel has the cross-link network microstructure which is similar to that of the natural bovine knee articular cartilages.With the increase of freezing-thawing cycles and the HA content, the degree of cross-link and the crystallization of PVA/HA composite hydrogel both increase, the elastic modulus increases evidently, the rate of stress relaxation is improved and the value of balance stress decreases.The friction coefficient decreases with the increase of the freezing-thawing cycles and the HA content.The more the freezing-thawing cycles are, the earlier the friction coefficient reaches the stable balance value.The friction deformation depth between PVA/HA composite hydrogel and bovine knee articular cartilage is inversely proportional to freezing-thawing cycles and the HA content.The main wear mechanisms of PVA/HA composite hydrogel are plastic flowing and adhesive flaking.The wear severity degree decreases with the increase of freezing-thawing cycles and the HA content.

Management of vascular complications following calcium hydroxylapatite filler injections:a systemic review of cases and experimental studies

Aim:Dermal fillers are increasingly popular procedures.Inadvertent intraarterial injection of fillers,particularly with calcium hydroxylapatite(CaHA),can result in devastating consequences.A systemic review was performed to summarize management strategies to treat CaHA-associated vascular complications.Methods:The methodology of this review was derived from The Preferred Reporting Items for Systematic Reviews and Meta-analyses(PRISMA).In addition,this paper presents a previously unreported case of a CaHA-associated vascular complication.Results:There were 32 articles describing 42 cases,plus our case included in this review.There were 15 cases of vision complications,23 cases of non-vision complications,and 5 experimental studies.The most common injection sites reported were nasal region for vision complications(45%)and nasolabial folds for non-vision complications(40%).Of the 38 human cases,the most prevalent treatment choice was steroids(24 cases,63%).Complete or near complete improvement was reported in 83%of non-vision complications and 40%of vision complications.There was no noticeable homogeneity in the management strategies and outcomes of the patients.Of the 5 experimental studies,no clear consensus on treatments was found.Conclusion:Vascular complications of CaHA are seemingly uncommon,but it is widely suspected that this is due to underreporting.While best management is prevention,preparation for a potential complication is equally important.Derived from CaHA literature,hyaluronic acid filler complication protocols,findings of this review,and personal experiences,this report proposes management strategies for CaHA-associated vascular complications.We hope these strategies provide a much-needed framework for injectors to refer to and utilize as needed.