bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydroxylapatite/Plaster Implantation for the Treatment of Severe Periodontal Osseous Defects
Authors: Carnevale Reynolds A. , Greco George W. , Bullard Cindy M. , Hanker Jacob S. 
Published: March 2011

AbstractInfrabony defects of 230 periodontal patients have been treated surgically by implantation. These lesions of alveolar bone, up to nineteen per patient, generally displayed pocket depths of at least 8mm and were associated with teeth showing pronounced mobility. Approximately 50% of these teeth could have ordinarily been condemned to extraction. In this study, scaling, root planing, and polishing were performed and patients were instructed in oral hygiene measures prior to surgical implantation. A 1:1 mixture of dense sintered hydroxylapatite(HA) particles (OrthoMatrix HA-500) with plaster of Paris (USG Medical Grade Calcium Sulfate Hemihydrate B, containing 0.85% K2SO4) was moistened with a minimum amount of saline. The mixture was then implanted into the dried defect. After setting, the operative site was closed with silk sutures. The plaster bound the HA particles in the defects and prevented particle straying which frequently occurs when they are implanted with saline alone or with other vehicles. There was an almost immediate and sustained diminution in tooth mobility at most implantation sites. Good retention of particles was seen on physical and radiographic examination of most defects for the length of the study (5 years). Overall, there was a marked reduction in pocket depth and improvement in tissue tone and texture. Less than 1% of the teeth at the implantation sites have been lost. No significant inflammation has been observed. Increased radiopacity and resistance to probing suggest bone formation in some implanted defects. Implantation of periodontal osseous defects with the biocompatible HA/plaster composite appears to result in the clinical cessation of progressive periodontal disease.
UCSF Multichannel Cochlear Implants
Authors: Schindler Robert A. , Kessler Dorcas K. 
Published: March 2011

AbstractClinical trials with the UCSF/Storz multichannel cochlear implant began in February 1985. The final patient in this series was implanted in June 1986. The objective of the clinical trial was to evaluate the strategies developed by the UCSF implant team through neurophysiological, histopathological, and psychophysical investigations over the past seventeen years. A total of 16 patients were implanted with this four channel unit, a vocoder-based, compressed-analog system. Results are measured with a battery of speech reception tests, including routine audiometric tasks used to evaluate standard clinical populations. Assessments are administered using conventional audiologic procedures. Tests include monosyllabic word recognition (the standard clinical “speech discrimination” list) and the recognition of key words in sentences. Eleven of the 16 patients have now had their one-year postoperative evaluations, permitting observations on their performance over time. Of these 11 patients, ten (91%) are able to obtain a considerable degree of auditory speech recognition. Relative to other cochlear implant projects, this represents an extremely high proportion of the implant population achieving some level of auditory-only speech understanding. The UCSF/Storz clinical trial has helped to clarify and define the specifications for our next generation implant, an elecrically transparent sixteen channel system.
Conduction Properties in Peripheral Nerve Fibers Regenerated by Biodegradable Polymer Matrix
Authors: Chang Albert S. , Yannas Ioannis V. , Krarup Christian , Sethi Rajesh , Norregaard Thor V. , Zervas Nicholas T. 
Published: March 2011

AbstractThe rat sciatic nerve was transected mid-thigh and grafted with a silicone tube, the central 10 mm of which was filled with a collagen-glycosaminoglycan (CG) matrix. The rats were grafted contralaterally with empty silicone tubes as controls. The earliest compound muscle action potentials (CMAP's) at the plantar muscles were recorded around 11 weeks. After 30 weeks, the distal motor latencies recovered to about 50% higher than normal, the conduction velocity to about 50% normal, and the amplitudes of the CMAP's to about 50% normal. Of 7 rats in this study, all 7 nerves grafted with the CG matrix exhibited recovery, while only 1 grafted with the empty tube exhibited recovery. The CG matrix therefore appears to promote functional nerve regeneration across extended distances.
In-Vivo Screening of Platelet-Biomaterial Interactions in a Baboon Model
Authors: Yeager Anson A. , Hussein H. , Shoenfeld N. , Ramberg K. , Connolly R. , Callow A. D. 
Published: March 2011

AbstractA percutaneous in-vig venous model was characterized by testing platelet deposition on standard vascular prosthetic materials in the baboon. The model detected significant difference in platelet deposition on ePTFE compared to Dacron. Low molecular weight dextran was administered following a baseline test period. A significant decrease in platelet depositionr occurred for both materials and coincided with a prolongation in bleeding time. No consistent decrease was found in control experiments which used no bolus or a saline bolus for treatment. Advantages of the model included ease of use and adaptability to test large numbers of materials. The model was suItable for in-vivo screening of platelet interactions with biomaterials placed in the bloodstream.
Generation of Differentiating Human Epidermal Cells on Basement Membrane Matrigel: Potential for use as Autografts in Recurrent Ulcerative Lesions
Authors: Walker-Jones Dorothy G. , Reindorf C. A. , Massac E. , Adekile A. D. , Hall M. G. , Nunez A. I. 
Published: March 2011

AbstractThe successful use of in vitro-generated skin autografts in the treatment of burns in humans (Green and O'Connor, 1984) has advanced the potential for application in the treatment of recurrent ulcerative lesions that occur in some patients with sickle cell disease and other disorders. Conventional grafts frequently break down in these patients, requiring repeated grafting that may eventually result in the lack of suitable donor sites. Preliminary studies show that Type I collagen (Collistat) promotes healing of sickle cell-lesions but with extensive scarring and loss of pigmentation (Adekile et al., 1987). Therefore, the primary aim of this study was the development of a culture procedure for the rapid generation of differentiating human epidermal cells on a biomatrix for use in conjunction with the Collistat, and later, the establishment of a frozen culture bank. Dispasefollowed by trypsin-dissociated inner epidermal cells from dermatome sections of skin of adult patients undergoing elective plastic surgery were cultured on basement membrane-derived Matrigel (Collaborative Research, Inc.) coated onto plastic coverslips. Growth was established in RPMI1640 or IMEM supplemented with insulin, transferrin, hydrocortisone and bovine pituitary extract or Keratinocyte Growth Medium (KGM)a nd from 0.5–2.0% fetal bovine serum. The epidermal cells exhibited active migration and the formation of bi- and tri-layered aggregates by day 3. Large multilayered aggregates were produced in KGM with 1.16 mM CaCl2 added. Electron microscopic observations revealed increased numbers of desmosomal junctions, interdigitations and apical-basal polarity in these aggregates. A distinguishing feature ofthese and other cells grown on Matrigel is the absence of the degree of spreading that is characteristic of cells grown on plastic. It is noteworthy that the epidermal cells did not invade through the Matrigel.
Dimac: A New Delivery System for Silver Sulfadiazine
Authors: Miller Linden M. , Hansbrough John F. 
Published: March 2011

AbstractWound care for burn victims is painful and tedious, but necessary to avoid the ever-present problem of infection. In an effort to circumvent daily dressing changes while ensuring optimal wound protection, DIMAC, a new drug delivery system for the commonly used topical antimicrobial silver sulfadlazine, has been developed. When incorporated into the delivery system, silver sulfadiazine is released in a sustained fashion. The results of an evaluation of the safety and efficacy of DIMAC in the treatment of full-and partial-thickness burn wounds are described here. DIMAC, left In place for up to 4 days, appears to be as effective as twice-daily cleansing and application of silver sulfadiazine cream.
The Feasibility of a Semiconductor-Laser Glucose-Detection System for Insulin-Pump Therapy
Authors: Arrieta I. C. , Burk D. E. , Batich C. 
Published: March 2011

AbstractA potentially implantable semiconductor-laser-based sensor is demonstrated to be feasible for glucose detection at concentrations found in the human blood. In the system, the monochromatic, linearly polarized light from a diode laser is directed into an external cavity with a second diode laser at the far end. The cavity is filled with a glucose solution of varying physiological concentrations. The interference of the rotated, polarized light from the first diode laser with that of the second laser is monitored by a photodiode, forming an optoelectronic pair with the first diode laser. A variation in glucose concentration of 0.1 to 0.3 g/dl results in a 5% variation in the photodiode current. This variation is sufficient to provide feedback to an insulin pump.
A Review of Fracture Mechanics in Compact Bone
Authors: Moyle David D. 
Published: March 2011

AbstractA review of the literature of the past twenty years on the measurements of fracture properties of compact bone, including measurements of critical stress intensity factors, critical strain energy release rates, measurements of “surface free energies” by impact tests, work of fracture tests and other methods, with an emphasis on the relation of fracture measurements to microstructure is presented. Recent results from the author's laboratory on the relation of work of fracture measurements to specimen size and microstructure are presented.
Finite Element Analysis in Orthopaedics
Authors: Koeneman James B. 
Published: March 2011

AbstractPredicting the stress state in bones is important to the understanding of bone remodeling and the long-term reliability of total joint implants. Beam theory, 2-D and 3-D finite element analysis have been used to calculate stress distributions. These finite element analyses of bone structures are progressing from crude models for which the clinical relevance has been questioned to an important tool which is necessary to understand stress related bone changes.
Microstructure and Elastic Properties of Dental Resin and Resin-Based Glass-Reinforced Composites: XRD, SEM and Ultrasonic Methods
Authors: Singh Surendra , Katz J. Lawrence , Antonucci J. , Penn R. W. , Tesk J. A. 
Published: March 2011

AbstractThe load-bearing ability of dental restorative materials under cyclic high-stress applications depends upon mechanical properties established by the composition and microstructure. The microstructure and the elastic properties of neat resin and two resin-based glass-reinforced composites have been studied. The microstructure of these materials has been examined using x-ray diffractometry (XRD), scanning electron microscopy (SEM) including energy dispersive spectrometry (EDS). The elastic properties, i.e., Young's, shear and bulk moduli and Poisson's ratio were determined from ultrasonic velocities and densities. The ultrasonic velocities were measured using a pulse-through transmission method; density was measured using a buoyant force method. These studies showed that: (1) these materials have amorphous structures; (2) these materials have Young's moduli of the order of 20 GPa, and (3) the silane couplant apparently did not significantly affect the elastic properties of these resin-based composites.
Electrochemical Charge and Protein Adsorption
Authors: Mueller Herbert J. 
Published: March 2011

AbstractThe amount of albumin adsorbed to three dental crown and bridge alloys (high- and low-gold content and silver-palladium), platinum, silver, and stainless steel was quantitated for the as-immersed conditions as well as with anodic and cathodic charge transfers in artifical saliva at a pH = 6.8. A methanolchloroform technique was utilized prior to protein assay which precipitated protein by phase separation. Amido black staining of protein on nitrocellulose filter paper was evaluated for optical density and compared to a standard curve of known quantities of protein. Cathodic charges decreased the quantity of adsorbed protein while anodic charges both increased and decreased adsorbed protein depending upon metal or alloy. Quantities adsorbed ranged from 0.5 to 8 μg/cm2. Interaction of positive oxidized species with the excess negative charges of the albumin molecules is thought to have increased protein adsorption. Formation of corrosion products with inorganic conponents is thought to have masked positive charges from protein thereby decreasing adsorption.
Phosphate Glass Dental/medical Cement
Authors: Chen Wei-Shi , Monroe E. A. 
Published: March 2011

AbstractCurrent interest in the clinical application of alloplastic grafts for treating dental and orthopedic bone defects suggested this investigation on phosphate glasses. Particularly, the calcium phosphate ceramic materials of hydroxyapatite and tricalcium phosphate appear to be promising graft materials. Our interest in amorphous rather than crystalline ceramics centered on the potentially wide compositional variation that may be possible and their concomittant properties such as solubility.
Production of Highly Adherent Hydroxylapatite Coatings by Ion Beam and Plasma Techniques
Authors: Stevenson James R. , Solnick-Legg Hillary , Legg Keith O. 
Published: March 2011

AbstractStarting with a pure hydroxylapatite sputter target, highly adherent coatings have been produced on metals and polymers by combining rf sputter deposition and ion implantation techniques. Reflection high energy electron diffraction (RHEED) scratch and adhesion tests have been done and more analysis is planned. Comparison of the RHEED data with HA and tricalcium phosphate standards shows the material to be polycrystalline hydroxylapatite rather than the amorphous, hydroxyl-free material usually produced by similar methods. Because of its structure this coating is expected to be nonresorbable. The coating is non-porous, hard and scratch-resistant. Data on the crystallography and mechanical properties of the coating will be presented.
Immunoadsorption and Absorptive Cell Separation
Authors: Yamazaki Z. , Kanai F. , Hiraishi M. , Idezuki Y. , Inoue N. , Tsuda N. , Katoh H. , Ide K. , Umegae M. , Ohno K. 
Published: March 2011

AbstractAs a means of selectively removing pathogenic macromolecular substances, an affinity adsorbent or immunoadsorbent has been investigated in experimental and clinical studies on blood purification in the treatment of immune diseases. There are several affinity adsorbents currently available for clinical application. The authors developed physicochemical affinity adsorbents Immusorba IM-TR and IM-PH, whose experimental and clinical evaluations have been satisfactory in several immune diseases, such as rheumatoid arthritis, myasthenia gravis, systemic lupus erythematosus and multiple sclerosis.Absorptive cell separation, for leucocyte-free blood transfusion or for cytapheresis, has been developed using a leucocyte removal filter, whose container has fine, long fibers of polyester which are densely packed. The filters Sepacell and Cellsorba are used for erythrocyte transfusion and cytapheresis, respectively. In experimental and clinical trials, they provide efficient removal of leucocytes. Erythrocytes can be recovered virtually without loss. Clinical evaluation is now being conducted.In conclusion, the above-mentioned new methods provide promising immunomodulations for the treatment and for the clearification of pathphysiology of immune diseases.
Effects of Nonspecific Cell/Surface Interactions on Cell Affinity Chromatographic Separations
Authors: Hammer Daniel A. , Lauffenburger Douglas A. 
Published: March 2011

AbstractExploitation of specific cell membrane receptor molecules is a promising avenue for the separation and purification of particular cell populations for biomedical and biotechnological purposes. Cell affinity chromatography is a technique which uses this principle to separate cells. In it, ligand molecules with a high binding affinity for specific receptors on targeted cell populations are immobilized on surfaces over which mixed cell populations are passed. These targeted populations are preferential retained, affecting a separation.Often, the resulting separation is not as selective or efficient as the receptor/ligand biochemistry would promise. We present a theoretical analysis which elucidates the role of physical factors, such as van der Waals, electrostatic, and fluid mechanical forces, in affecting cell adhesiveness and hence selectivity. We demonstrate that only fairly narrow ranges of parameters characterizing these forces permit the selectivity inherent in the receptor/ligand biochemistry.
Measurement of Thromboembolism: Application to Patients with a Jarvik Total Artificial Heart
Authors: Adams George A. , Labow Brian , Carmody Ian , Hallee Christiane , Keon Wilbert J. 
Published: March 2011

AbstractThere have been in excess of 90 implantations of several different types of artificial heart (TAH) into patients. The bulk of these implantations have been using the Jarvik TAH as a bridge to provide interim circulatory support for the failed heart while a donor heart is being located and transported. Attempt to use the Jarvik TAH as a permanent, long-term heart substitute were complicated by hemorrhaging, sepsis, peripheral-organ failure and strokes [1]. These latter sequelae are thought to be due to thromboembolism and this concept is supported by the examination of explanted TAH from Barney Clark, the first recipient of the Jarvik TAH, which revealed large thrombus formation around the valve seats and microthrombi on the diaphragm that may have been the sites of thromboemboli [2]. In the case of bridges, the implantation periods are shorter, averaging 10 to 14 days but still a significant number of these patients have had thromboembolic events and explanted TAH have had microscopic aggregations of platelets and thrombi [3,4]. The response of blood to the constituent biomaterials of all cardiovascular devices is highly variable [5]. The documentation of thrombus on a biomaterial surface does not prove it will detach nor does the lack of thrombus on a surface indicate that the surface is benign, as thrombus could have formed and embolized. We have used two approaches to study the dynamic process of thrombogenesis and thromboembolism, in vivo and in vitro. Whole arterial blood samples were analyzed for thromboemboli as an in vivo assessment and epifluorescent videomicroscopy was used to monitor the mechanism of thrombosis, in vitro. Microparticles were found in the arterial circulation of patients with a Jarvik TAB and platelet thrombi were observed to form and embolize from Biomer-coated surfaces during perfusion.
Synthesis of Artificial Models of Sickle Red Cells
Authors: Macgregor Roderick D. , Taylor Noel , Lubin Bertram , Hunt C. Anthony 
Published: March 2011

AbstractThe primary role of a red cell substitute is to deliver oxygen to cells eitherin vivo or in vitro. It seems reasonable to mimic evolution, which solved the problem of oxygen delivery in many species by encapsulating oxygen carrying proteins in cell-sized delivery systems. We have successfully synthesized and tested an artificial red cell (Neohemocytes: see Science 230, 1165, 1985). How many properties or functions of red cells can one mimic synthetically? Can these synthetic cells serve as useful models? Here we report the first successful synthesis of an artificial model sickle cell. No reproducible, model cell system was previously available for research. A procedure identical to that used to prepare normal neohemocytes (NHC) was employed using sickle hemoglobin (HbS). The starting material was O2or CO liganded HbS at a concentration of approximately 15g% in a 30 mOsm phosphate buffer; this solution was kept ultrahypotonic until the final stage of the process. The lipid bilayer membrane was formed during a prolonged adjustment of the osmolality to 300 mOsm. The final step was removal of unencapsulated HbS. Sickle NHC were examined in parallel with normal (HbA containing) NHC by scanning and thin section electron microscopy before and after deoxygenation. These synthetic cells do sickle! Some look remarkably like red blood cells, only much smaller. Our data suggests that polymerization of the HbS within sickle NHC may be initiated by a different mechanism than the polymerization of purified solutions of HbS. The typical lipid bilayer seen in HbA containing NBC was essentially absent in the sickle NHC: similar results have been reported for irreversibly sickled red cells. Sickle NHC thus have remarkable potential to function as model sickle cells.
For1ation of Zeolites: A Molecular Description
Authors: Dutta Prabir K. , Puri M. , Shieh D. C. 
Published: March 2011

AbstractRaman spectroscopy of the solution, solid and gel phases present during crystallization of zeolite X was investigated. The vibrational data indicate that an amorphous aluminosilicate solid, composed primarily of four membered aluminosilicate rings is in contact with monomeric silicate ions during the prenucleation stages of the zeolite formation. No intermediate building blocks specific to zeolite X could be discerned from the vibrational spectra. The influence of a series of monovalent cations on the crystallization process was also examined, and a model of zeolite formation has been proposed.
Cocation Effects in Rhodium-Exchanged Y Zeolites
Authors: Shoemaker R. K. , Johnson R. A. , Apple T. M. 
Published: March 2011

AbstractMagic-angle spinning13C NMR spectra of carbon monoxide adsorbed on rhodium/Y zeolites yield information about the proportioning of CO in the various possible adsorption states; linear, bridged and dicarbonyl. The relative amounts of these adsorbed types, particularly the ratio of bridged to linear CO is influenced by the nature of the majority cations present with the rhodium. Reduced Rh-Na(+) and Rh-Li(+) zeolites form all three CO surface species, while acidic Rh zeolites, formed by the introduction of the co-cations Ca(2+) and H(+), exhibit no bridged carbonyls. The suppression of the bridged moiety results from the withdrawal of electrons from rhodium by the acid centers making the metal electron deficient (more oxidized).Rh(I) dicarbonyl species form on all samples studied, however these species are indistinguishable from the linear monocarbonyls based solely upon the isotropic chemical shift obtained from magic-angle spinning. The number of dicarbonyl species can be quantitatively determined by the Carr- Purcell-Meiboom-Gill sequence, the powder pattern or by selective exchange experiments. At room temperature the two CO molecules in the gemdicarbonyl appear to undergo a mutual hopping exchange. This motion is frozen out at 198K. The carbon-carbon internuclear separation in the gemdicarbonyl is 3.3 Å.Catalysts pre-adsorbed with13CO undergo exchange of the dicarbonyl species upon exposure at 198 K to12CO, however they also react to form13CO2. When exposed to CO at room temperature no CO2formation is detected.