scholarly journals Hydroxylapatite and Related Minerals in Bone and Dental Tissues: Structural, Spectroscopic and Mechanical Properties from a Computational Perspective

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 728
Author(s):  
Gianfranco Ulian ◽  
Daniele Moro ◽  
Giovanni Valdrè
Keyword(s):  
Dynamic Properties ◽  
The Body ◽  
Atomic Scale ◽  
Hard Tissue ◽  
Mineral Phase ◽  
Organic Part ◽  
Dental Tissues ◽  
Biological Apatite ◽  
Physical And Chemical ◽  
Material Composite

Hard tissues (e.g., bone, enamel, dentin) in vertebrates perform various and different functions, from sustaining the body to haematopoiesis. Such complex and hierarchal tissue is actually a material composite whose static and dynamic properties are controlled by the subtle physical and chemical interplay between its components, collagen (main organic part) and hydroxylapatite-like mineral. The knowledge needed to fully understand the properties of bony and dental tissues and to develop specific applicative biomaterials (e.g., fillers, prosthetics, scaffolds, implants, etc.) resides mostly at the atomic scale. Among the different methods to obtains such detailed information, atomistic computer simulations (in silico) have proven to be both corroborative and predictive tools in this subject. The authors have intensively worked on quantum mechanical simulations of bioapatite and the present work reports a detailed review addressed to the crystal-chemical, physical, spectroscopic, mechanical, and surface properties of the mineral phase of bone and dental tissues. The reviewed studies were conducted at different length and time scales, trying to understand the features of hydroxylapatite and biological apatite models alone and/or in interaction with simplified collagen-like models. The reported review shows the capability of the computational approach in dealing with complex biological physicochemical systems, providing accurate results that increase the overall knowledge of hard tissue science.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

scholarly journals Identification of Dynamic Parameters of Pedestrian Walking Model Based on a Coupled Pedestrian–Structure System

2021 ◽  
Vol 11 (14) ◽  
pp. 6407
Author(s):  
Huiqi Liang ◽  
Wenbo Xie ◽  
Peizi Wei ◽  
Dehao Ai ◽  
Zhiqiang Zhang
Keyword(s):  
Negative Correlation ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Field Testing ◽  
The Body ◽  
Structural Vibration ◽  
Pedestrian Dynamics ◽  
Structure Interaction ◽  
Mass Spring ◽  
Stiffness And Damping

As human occupancy has an enormous effect on the dynamics of light, flexible, large-span, low-damping structures, which are sensitive to human-induced vibrations, it is essential to investigate the effects of pedestrian–structure interaction. The single-degree-of-freedom (SDOF) mass–spring–damping (MSD) model, the simplest dynamical model that considers how pedestrian mass, stiffness and damping impact the dynamic properties of structures, is widely used in civil engineering. With field testing methods and the SDOF MSD model, this study obtained pedestrian dynamics parameters from measured data of the properties of both empty structures and structures with pedestrian occupancy. The parameters identification procedure involved individuals at four walking frequencies. Body frequency is positively correlated to the walking frequency, while a negative correlation is observed between the body damping ratio and the walking frequency. The test results further show a negative correlation between the pedestrian’s frequency and his/her weight, but no significant correlation exists between one’s damping ratio and weight. The findings provide a reference for structural vibration serviceability assessments that would consider pedestrian–structure interaction effects.

Seismic cone penetration test and seismic tomography in permafrost

2004 ◽  
Vol 41 (5) ◽  
pp. 796-813 ◽  
Author(s):  
Anne-Marie LeBlanc ◽  
Richard Fortier ◽  
Michel Allard ◽  
Calin Cosma ◽  
Sylvie Buteau
Keyword(s):  
Seismic Tomography ◽  
Dynamic Properties ◽  
Cone Penetration Test ◽  
The Body ◽  
Body Waves ◽  
Reconstruction Technique ◽  
Seismic Velocities ◽  
Penetration Test ◽  
Cone Penetration ◽  
Seismic Cone Penetration Test

Two high-resolution multi-offset vertical seismic profile (VSP) surveys were carried out in a permafrost mound near Umiujaq in northern Quebec, Canada, while performing seismic cone penetration tests (SCPT) to study the cryostratigraphy and assess the body waves velocities and the dynamic properties of warm permafrost. Penetrometer-mounted triaxial accelerometers were used as the VSP receivers, and a swept impact seismic technique (SIST) source generating both compressional and shear waves was moved near the surface following a cross configuration of 40 seismic shot-point locations surrounding each of the two SCPTs. The inversion of travel times based on a simultaneous iterative reconstruction technique (SIRT) provided tomographic images of the distribution of seismic velocities in permafrost. The Young's and shear moduli at low strains were then calculated from the seismic velocities and the permafrost density measured on core samples. The combination of multi-offset VSP survey, SCPT, SIST, and SIRT for tomographic imaging led to new insights in the dynamic properties of permafrost at temperatures close to 0 °C. The P- and S-wave velocities in permafrost vary from 2400 to 3200 m/s and from 900 to 1750 m/s, respectively, for a temperature range between –0.2 and –2.0 °C. The Young's modulus varies from 2.15 to 13.65 GPa, and the shear modulus varies from 1.00 to 4.75 GPa over the same range of temperature.Key words: permafrost, seismic cone penetration test, vertical seismic profiling, seismic tomography, dynamic properties.

TO THE QUESTION OF INDUSTRIAL AEROSOL CONTROL IN THE PROCESSING OF BLISTER COPPER

2021 ◽  
Author(s):  
O.G. Drugova ◽  
◽  
A.A. Fedoruk ◽  
T.N. Shtin
Keyword(s):  
Chemical Properties ◽  
The Body ◽  
Industrial Control ◽  
Silicon Iron ◽  
Carcinogenic Effect ◽  
Copper Zinc ◽  
Toxic Potential ◽  
Physical And Chemical ◽  
Industrial Aerosol ◽  
And Chemical Properties

Abstract. Due to the predominance of PM1 particles in the air samples, the following metals were found in the aerosol: copper, zinc, silicon, iron, lead, sulfur, arsenic, aluminum, antimony, tin, magnesium, cadmium and several other metals. The content of sulfates was significantly noted. These physical and chemical properties show a considerable toxic potential of industrial aerosol. The MPC of lead, sulfur and silicon dioxides, as well as nitrogen oxides and formaldehyde were detected in the working air. Meanwhile, copper, zinc, and iron did not exceed their MPC. Moreover, an underestimation of the aerosol was observed within the framework of industrial control. It has been found that the aerosol components may have an irritating, reprotoxic, allergenic, and carcinogenic effect on the body. Further consideration of the dispersed and chemical composition of the aerosol is required to determine the concentration of identified substances in the working air and the limiting components determining its biological effect.

scholarly journals Soft Tissue Applications of Er,Cr:YSGG Laser in Pediatric Dentistry

2017 ◽  
Vol 10 (2) ◽  
pp. 188-192 ◽  
Author(s):  
Ferah Rehman ◽  
Vivek Chaturvedy
Keyword(s):  
Soft Tissue ◽  
Laser Energy ◽  
Case Series ◽  
Pediatric Dentistry ◽  
Patient Comfort ◽  
Operating Efficiency ◽  
Hard Tissue ◽  
Contact Mode ◽  
Tooth Structure ◽  
Dental Tissues

ABSTRACT Soft tissue laser, such as diode and Nd:YAG lasers were initially used in soft tissue lesions because of its increased success rate. It was because of the fact that these lasers were well-absorbed by chromophores, such as hemoglobin and melanin which are found abundant in the oral mucosa. The introduction of erbium family in 1990 comprising the Er:YAG and Er,Cr:YSGG lasers made the hard tissue laser a boon for dentistry. Erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG) was introduced in 1997 for the surgical needs of clinical dentistry in general practice. The erbium belongs to the rare earth which is embedded in a host crystal. The actual lasing process takes place in the Er ion Er3+. Two host crystals consisting of yttrium, aluminum, and garnet (Y3A5O12) and yttrium, scandium, gallium, and garnet (Y3Sc2Ga3O12) are added to the erbium. The interest to use these hard tissue laser in the treatment of soft tissue lesion was because of the properties of these lasers which are well-absorbed by chromophore water apart from hydroxy appetite crystals. Erbium laser energy is absorbed by collagen, hydroxyapatite, and water components. It allows the laser to cut soft tissue, tooth structure, and bone. In the noncontact mode, the incision is scalpel-like, with very little hemostasis. In contact mode, it performs soft tissue sculpting with adequate hemostasis. The Er,Cr:YSGG is the world's most advanced dental laser, which is ideal all-tissue laser because all dental tissues contain water, for the multidisciplinary dentist who performs a broad spectrum of procedures. It delivers the highest level of clinician control, operating efficiency, flexibility in tip, and accessory selection. For optimal clinical results and patient comfort in hard and soft tissue procedures, the erbium lasers have set a new standard of clinical performance. The present case series aims to highlight the various soft tissue applications of Er,Cr:YSGG (Waterlase Biolase®, Biolase, Inc, San Clemente, California, USA) in pediatric patients. How to cite this article Kumar G, Rehman F, Chaturvedy V. Soft Tissue Applications of Er,Cr:YSGG Laser in Pediatric Dentistry. Int J Clin Pediatr Dent 2017;10(2):188-192.

scholarly journals Prospects Of Using Walnut In Technologies Of Drinks

2015 ◽  
Vol 19 (2) ◽  
pp. 39-50
Author(s):  
Inna Tiurikova ◽  
Mykhailo Peresichnyi
Keyword(s):  
Raw Materials ◽  
Chemical Properties ◽  
The Body ◽  
Maturity Stage ◽  
Human Beings ◽  
Fruit And Vegetable ◽  
Biological Value ◽  
Vegetable Raw Materials ◽  
Main Components ◽  
Physical And Chemical

Abstract The results of studies in the field of beverage functionality using walnut are presented. The main components such as celery, Jerusalem artichokes, carrots, pumpkin and rhubarb, as a dietary supplement - extracts from walnut of milk-maturity stage are offered for creating blends. The basic physical and chemical properties of fruit and vegetable raw materials and semi-finished products created on the base of them have been studied, and their nutritional and biological value has been proved. Rational technologies of fruit and vegetable blends with nut additives have been identified. Their biological value has been confirmed. Drinks are recommended for use in the daily diet of human beings to satisfy thirst and enrich the body by biologically valuable components.

scholarly journals Qualidade de biodiesel de soja, mamona e blendas durante armazenamento

2016 ◽  
Vol 11 (5) ◽  
pp. 143
Author(s):  
Marco Aurélio R. Melo ◽  
Everton Vieira Da Silva ◽  
Guiseppe C. Vasconcelos ◽  
Eduardo H. S. Vasconcelos ◽  
Antonio Gouveia de Souza
Keyword(s):  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Acid Value ◽  
Storage Process ◽  
Technical Regulation ◽  
National Agency ◽  
Soybean Biodiesel ◽  
Physical And Chemical ◽  
Natural Additive

<p>Objetivou-se monitorar o armazenamento dos biodieseis provenientes da transesterificação homogênea alcalina do óleo de soja e mamona via rota metílica, avaliando a indução oxidativa pela norma EN14112 e pelo método PetroOxy durante o período de 120 dias, também observou-se o comportamento dos biodieseis inseridos em blendas nas proporções de 20, 30, 40 e 50% v/v de biodiesel de mamona ao biodiesel de soja denominadas de M20, M30, M40 e M50 (em recipientes de aço-carbono fechado). Conforme análises físico-químicas, as especificações para ambos biodiesel e blendas satisfizeram as exigências dos limites permitidos pelo Regulamento Técnico nº 14/2012 da Agência Nacional do Petróleo, Gás Natural e Biocombustíveis. Exceção das análises de estabilidade oxidativa (M0, M20, M30 e M40), do índice de acidez após 60 dias (M50), após 90 dias (M40 e M50), após 120 dias (M100) e da viscosidade cinemática (M40, M50 e M100) que apresentaram valores fora dos limites estabelecidos pela norma. As propriedades fluidodinâmicas apresentaram comportamentos semelhantes para os biodieseis metílicos e blendas, assim, nestas concentrações o biodiesel metílico de mamona atua como um aditivo natural ao biodiesel metílico de soja. Através do método EN 14112 verificou-se que a blenda M50 é mais resistente ao processo de oxidação durante armazenamento de 120 dias.<strong></strong></p><p align="center"><strong><em>Quality of biodiesel soy, castor beans and blends during storage</em></strong></p><p><strong>Abstract</strong><strong>: </strong>The objective of the study was to monitor the storage of biodiesels from alkaline homogeneous transesterification of soybean and castor oil via methyl route, and to evaluate the oxidative induction by the EN14112 standard and the PetroOxy method over the period of 120 days. We observed the behavior of the inserted biodiesels in blends in the ratios of 20, 30, 40 and 50% v / v biodiesel from castor beans of soybean biodiesel named M20, M30, M40 and M50 (closed carbon steel containers) . As physical and chemical analysis, specifications for both biodiesel and blends met the requirements of the limits allowed by the Technical Regulation No. 14/2012 of the National Agency of Petroleum (ANP). Exception of the oxidative stability analysis (M0, M20, M30 and M40), the acid value after 60 days (M50), after 90 days (M40 and M50), 120 days (M100) and kinematic viscosity (M40, M50 and M100) with values outside the limits established by the standard. The fluid-dynamic properties show similar behavior for blends methyl biodiesels and thus these concentrations methyl castor biodiesel acts as a natural additive to the methyl soybean biodiesel. By the method EN 14112 was found that M50 blend is more resistant to oxidation during storage process 120 days.</p>

Physical and chemical composition of the body of breeding sows with differing body subcutaneous fat depth at parturition, differing nutrition during lactation and differing litter size

1989 ◽  
Vol 48 (1) ◽  
pp. 203-212 ◽  
Author(s):  
C. T. Whittemore ◽  
H. Yang
Keyword(s):  
Chemical Composition ◽  
Energy Requirement ◽  
Subcutaneous Fat ◽  
Live Weight ◽  
Total Content ◽  
The Body ◽  
Large White ◽  
Body Protein ◽  
Weight Losses ◽  
Physical And Chemical

ABSTRACTThe physical and chemical composition of sows was determined at first mating (no. = 6), weaning the first litter (12) and 14 days after weaning the fourth litter (24). The sows were from 108 Large White/Landrace Fl hybrid gilts allocated in a factorial arrangement according to two levels of subcutaneous fatness at parturition (12 v. 22 mm P2), two levels of lactation feeding (3 v. 7 kg) and two sizes of sucking litter (six v. 10). Treatments significantly influenced the composition of dissected carcass fat and chemical lipid, but not composition of dissected lean and chemical protein. The final body protein mass of well fed sows at the termination of parity 4 was 41 kg, and the total content of gross energy (GE) in excess of 3000 MJ, with an average of 12·4 MJ GE per kg live weight; equivalent values for the less well fed sows were 33 kg and 9·4 MJ GE per kg live weight respectively. The weights of chemical lipid and protein could be predicted from the equations: lipid (kg) = -20·4 (s.e. 4·5) + 0·21 (s.e. 0·02) live weight + 1·5 (s.e. 0·2) P2; protein (kg) = -2·3 (s.e. 1·6) + 0·19 (s.e. 0·01) live weight - 0·22 (s.e. 0·07) P2. On average, sows lost 9 kg lipid and 3 kg protein in the course of the 28-day lactation; these being proportionately about 0·16 and 0·37 of the live-weight losses respectively. Maternal energy requirement for maintenance was estimated as 0·50 MJ digestible energy (DE) per kg M0·75, while the efficiency of use of DE for energy retention was 0·28.

scholarly journals Surface microtopography modulates sealing zone development in osteoclasts cultured on bone

2017 ◽  
Vol 14 (127) ◽  
pp. 20160958 ◽  
Author(s):  
Michal Shemesh ◽  
Lia Addadi ◽  
Benjamin Geiger
Keyword(s):  
Dynamic Properties ◽  
Complex Structure ◽  
Chemical Properties ◽  
Bone Diseases ◽  
Bone Homeostasis ◽  
Native Bone ◽  
Surface Microtopography ◽  
Significant Enrichment ◽  
Sealing Zone ◽  
Physical And Chemical

Bone homeostasis is continuously regulated by the coordinated action of bone-resorbing osteoclasts and bone-forming osteoblasts. Imbalance between these two cell populations leads to pathological bone diseases such as osteoporosis and osteopetrosis. Osteoclast functionality relies on the formation of sealing zone (SZ) rings that define the resorption lacuna. It is commonly assumed that the structure and dynamic properties of the SZ depend on the physical and chemical properties of the substrate. Considering the unique complex structure of native bone, elucidation of the relevant parameters affecting SZ formation and stability is challenging. In this study, we examined in detail the dynamic response of the SZ to the microtopography of devitalized bone surfaces, taken from the same area in cattle femur. We show that there is a significant enrichment in large and stable SZs (diameter larger than 14 µm; lifespan of hours) in cells cultured on rough bone surfaces, compared with small and fast turning over SZ rings (diameter below 7 µm; lifespan approx. 7 min) formed on smooth bone surfaces. Based on these results, we propose that the surface roughness of the physiologically relevant substrate of osteoclasts, namely bone, affects primarily the local stability of growing SZs.

scholarly journals Zirconia-Based Biomaterials for Hard Tissue Reconstruction

2018 ◽  
Vol 9 ◽  
pp. 1179061X1876788 ◽  
Author(s):  
Terawat Tosiriwatanapong ◽  
Weerachai Singhatanadgit
Keyword(s):  
Surface Modifications ◽  
Modern Medicine ◽  
Hard Tissue ◽  
Dental Tissues ◽  
Dental Prostheses ◽  
Tissue Reconstruction ◽  
Superior Mechanical Properties ◽  
Advanced Biomaterials ◽  
Dental Conditions ◽  
Implanted Devices

Implantable biomaterials are increasingly important in the practice of modern medicine, including fixative, replacement, and regeneration therapies, for reconstruction of hard tissues in patients with pathologic osseous and dental conditions. A number of newly developed advanced biomaterials have been introduced as promising candidates for tissue reconstruction. Among these, zirconia-based biomaterials have gained attention as a biomaterial for hard tissue reconstruction due to superior mechanical properties and good chemical and biological compatibilities. This review summarizes the types of zirconia, advantages of zirconia-based biomaterials for hard tissue reconstruction including bone and dental tissues, responses of tissue and cells to zirconia, and surface modifications for enhanced bioactivity of zirconia. Current and future applications of zirconia-based biomaterials for bone and dental reconstruction, ie, medical implanted devices, dental prostheses, and biocompatible osteogenic scaffolds, are also discussed.

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