Bücher zum Thema „Inorganic components“

Polymer chemistry and technology form one of the major areas of molecular and materials science. This field impinges on nearly every aspect of modern life, from electronics technology, to medicine, to the wide range of fibers, films, elastomers, and structural materials on which everyone depends. Although most of these polymers are organic materials, attention is being focused increasingly toward polymers that contain inorganic elements as well as organic components. The goal of Inorganic Polymers is to provide a broad overview of inorganic polymers in a way that will be useful to both the uninitiated and those already working in this field. There are numerous reasons for being interested in inorganic polymers. One is the simple need to know how structure affects the properties of a polymer, particularly outside the well-plowed area of organic materials. Another is the bridge that inorganic polymers provide between polymer science and ceramics. More and more chemistry is being used in the preparation of ceramics of carefully controlled structure, and inorganic polymers are increasingly important precursor materials in such approaches. This new edition begins with a brief introductory chapter. That is followed with a discussion of the characteristics and characterization of polymers, with examples taken from the field. Other chapters in the book detail the synthesis, reaction chemistry, molecular structure, and uses of polyphosphazenes, polysiloxanes, and polysilanes. The coverage in the second edition has been updated and expanded significantly to cover advances and interesting trends since the first edition appeared. Three new chapters have been added, focusing on ferrocene-based polymers, other phosphorous-containing polymers, and boron-containing polymers; inorganic-organic hybrid composites; and preceramic inorganic polymers.

This article describes the structure-induced quantum confinement effect in nanostructured crystals, a unique class of hybrid semiconductors that incorporate organic and inorganic components into a single-crystal lattice via covalent (coordinative) bonds to form extended one-, two- and three-dimensional network structures. These structures are comprised of subnanometer-sized II-VI semiconductor segments (inorganic component) and amine molecules (organic component) arranged into perfectly ordered arrays. The article first provides an overview of II-VI and III-V semiconductors, II-VI colloidal quantum dots, inorganic-organic hybrid materials before discussing the design and synthesis of I-VI-based inorganic-organic hybrid nanostructures. It also considers the crystal structures, quantum confinement effect, bandgaps, and optical properties, thermal properties, thermal expansion behavior of nanostructured crystals.

This chapter describes the productivity of phytoplankton, from the initial energy and chemical requirements for photosynthesis to the rate of production of heterotrophic organisms. Phytoplankton are the planktonic organisms which account for most of the primary production in the ocean. Their characteristic trophic mode is the production of organic compounds using energy from light and chemical elements from inorganic compounds, known as phototrophy, or more strictly photolithotrophy. This process uses water as the electron donor and the reduction of inorganic carbon producing sugars, from which all other cell components are made using inorganic forms of nitrogen, phosphorus, and all the other chemical elements needed to produce cells.

Calcium pyrophosphate (CPP) dihydrate crystals form extracellularly. Their formation requires sufficient extracellular inorganic pyrophosphate (ePPi), calcium, and pro-nucleating factors. As inorganic pyrophosphate (PPi) cannot cross cell membranes passively due to its large size, ePPi results either from hydrolysis of extracellular ATP by the enzyme ectonucleotide pyrophosphatase/phosphodiesterase 1 (also known as plasma cell membrane glycoprotein 1) or from the transcellular transport of PPi by ANKH. ePPi is hydrolyzed to phosphate (Pi) by tissue non-specific alkaline phosphatase. The level of extracellular PPi and Pi is tightly regulated by several interlinked feedback mechanisms and growth factors. The relative concentration of Pi and PPi determines whether CPP or hydroxyapatite crystal is formed, with low Pi/PPi ratio resulting in CPP crystal formation, while a high Pi/PPi ratio promotes basic calcium phosphate crystal formation. CPP crystals are deposited in the cartilage matrix (preferentially in the middle layer) or in areas of chondroid metaplasia. Hypertrophic chondrocytes and specific cartilage matrix changes (e.g. high levels of dermatan sulfate and S-100 protein) are related to CPP crystal deposition and growth. CPP crystals cause inflammation by engaging with the NALP3 inflammasome, and with other components of the innate immune system, and is marked with a prolonged neutrophilic inflitrate. The pathogenesis of resolution of CPP crystal-induced inflammation is not well understood.

In Tanzania, structural adjustment policies implemented during the 1980s removed all agricultural subsidies. However, declining productivity and production of maize and rice—the main food crops—forced the government to restore subsidies in 2003. This chapter examines the impact of the agricultural input subsidy programme, looking at farmers’ response to subsidized inorganic fertilizer and improved maize and rice seed—discerning gender and temporal impacts. Farmers in Iringa and Morogoro were highly responsive to the fertilizer and seed components of the input subsidy, and their response was sensitive to the magnitude of the subsidy. Farmers in Morogoro were less responsive to both technologies due to dominance of rice production. Adoption was lower for female-managed farms, with corresponding lower livelihood outcomes, attributed to lower resource endowment. It is therefore recommended that underperforming farmers, including female farm manages in lower wealth ranks, required initiative to improve their productivity and production.

The discovery of new materials and the manipulation of their exotic properties for device fabrication is crucial for advancing technology. Nanoscience and the creation of nanomaterials have taken materials science and electronics to new heights for the benefit of mankind. Advanced Materials and Nanosystems: Theory and Experiment cover several topics of nanoscience research. The compiled chapters aim to update students, teachers, and scientists by highlighting modern developments in materials science theory and experiments. The significant role of new materials in future technology is also demonstrated. The book serves as a reference for curriculum development in technical institutions and research programs in the field of physics, chemistry, and applied areas of science like materials science, chemical engineering, and electronics. This part covers 12 topics in these areas: - Carbon and boron nitride nanostructures for hydrogen storage applications - Nanomaterials for retinal implants - Materials for rechargeable battery electrodes - Cost-effective catalysts for ammonia production - The role of nanocomposites in environmental remediation - Optical analysis of organic and inorganic components - Metal-oxide nanoparticles - Mechanical analysis of orthopedic implants - Advanced materials and nanosystems for catalysis, sensing, and wastewater treatment - Topological Nanostructures - Hollow nanostructures

♦ Structure of bone is comprised of cells, matrix, and water♦ Bone consists broadly of three surfaces (periosteal, endosteal, and Haversian) and two membranes (periosteum and endosteum)♦ The blood supply of bone is derived from four main routes (nutrient, metaphyseal, epiphyseal, and periosteal arteries)♦ There are three main types of cells in bone (osteoblast, osteocyte, and osteoclast)♦ The matrix is a composite material consisting of an organic and an inorganic component♦ Two types of bone formation are intramembranous and endochondral ossification♦ The skeleton is also involved in the vital homeostasis of calcium and phosphate.

Inorganic phosphate ions (H2PO4−/ HPO42−) (abbreviated as Pi) are involved in formation of bone and generation of high-energy bonds (e.g. ATP), metabolic pathways, and regulation of cellular functions. In addition, Pi is a component of biological membranes and nucleic acids. Only about 1% of total body Pi content is present in extracellular fluids, at a plasma concentration in adults within the range 0.8–1.4 mMol/L (at pH 7.4 mostly as HPO42−), with diurnal variations of approximately 0.2 mM. A small amount of plasma Pi is bound to proteins or forms complexes with calcium. Under normal, balanced conditions, absorption of dietary Pi along the small intestine equals the output of Pi via kidney and faeces. Renal excretion of Pi represents the key determinant for the adjustment of normal Pi plasma concentrations. Renal reabsorption of Pi occurs along the proximal tubules by sodium-dependent Pi cotransporters that are strictly localized at the apical brush border membrane. Parathyroid hormone (PTH) and FGF23 are key regulators amongst a myriad of factors controlling excretion of Pi in urine, mostly by changes of the apical abundance of Na/Pi cotransporters. Hypophosphataemia may result in osteomalacia, rickets, muscle weakness, and haemolysis. Hyperphosphataemia can lead to hyperparathyroidism and severe calcifications in different tissues.

Bones are multifunctional passive organs of movement that supports soft tissue and directly attached muscles. They also protect internal organs and are a reserve of calcium, phosphorus and magnesium. Each bone is covered with periosteum, and the adjacent bone surfaces are covered by articular cartilage. Histologically, the bone is an organ composed of many different tissues. The main component is bone tissue (cortical and spongy) composed of a set of bone cells and intercellular substance (mineral and organic), it also contains fat, hematopoietic (bone marrow) and cartilaginous tissue. Bones are a tissue that even in adult life retains the ability to change shape and structure depending on changes in their mechanical and hormonal environment, as well as self-renewal and repair capabilities. This process is called bone turnover. The basic processes of bone turnover are: • bone modeling (incessantly changes in bone shape during individual growth) following resorption and tissue formation at various locations (e.g. bone marrow formation) to increase mass and skeletal morphology. This process occurs in the bones of growing individuals and stops after reaching puberty • bone remodeling (processes involve in maintaining bone tissue by resorbing and replacing old bone tissue with new tissue in the same place, e.g. repairing micro fractures). It is a process involving the removal and internal remodeling of existing bone and is responsible for maintaining tissue mass and architecture of mature bones. Bone turnover is regulated by two types of transformation: • osteoclastogenesis, i.e. formation of cells responsible for bone resorption • osteoblastogenesis, i.e. formation of cells responsible for bone formation (bone matrix synthesis and mineralization) Bone maturity can be defined as the completion of basic structural development and mineralization leading to maximum mass and optimal mechanical strength. The highest rate of increase in pig bone mass is observed in the first twelve weeks after birth. This period of growth is considered crucial for optimizing the growth of the skeleton of pigs, because the degree of bone mineralization in later life stages (adulthood) depends largely on the amount of bone minerals accumulated in the early stages of their growth. The development of the technique allows to determine the condition of the skeletal system (or individual bones) in living animals by methods used in human medicine, or after their slaughter. For in vivo determination of bone properties, Abstract 10 double energy X-ray absorptiometry or computed tomography scanning techniques are used. Both methods allow the quantification of mineral content and bone mineral density. The most important property from a practical point of view is the bone’s bending strength, which is directly determined by the maximum bending force. The most important factors affecting bone strength are: • age (growth period), • gender and the associated hormonal balance, • genotype and modification of genes responsible for bone growth • chemical composition of the body (protein and fat content, and the proportion between these components), • physical activity and related bone load, • nutritional factors: – protein intake influencing synthesis of organic matrix of bone, – content of minerals in the feed (CA, P, Zn, Ca/P, Mg, Mn, Na, Cl, K, Cu ratio) influencing synthesis of the inorganic matrix of bone, – mineral/protein ratio in the diet (Ca/protein, P/protein, Zn/protein) – feed energy concentration, – energy source (content of saturated fatty acids - SFA, content of polyun saturated fatty acids - PUFA, in particular ALA, EPA, DPA, DHA), – feed additives, in particular: enzymes (e.g. phytase releasing of minerals bounded in phytin complexes), probiotics and prebiotics (e.g. inulin improving the function of the digestive tract by increasing absorption of nutrients), – vitamin content that regulate metabolism and biochemical changes occurring in bone tissue (e.g. vitamin D3, B6, C and K). This study was based on the results of research experiments from available literature, and studies on growing pigs carried out at the Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences. The tests were performed in total on 300 pigs of Duroc, Pietrain, Puławska breeds, line 990 and hybrids (Great White × Duroc, Great White × Landrace), PIC pigs, slaughtered at different body weight during the growth period from 15 to 130 kg. Bones for biomechanical tests were collected after slaughter from each pig. Their length, mass and volume were determined. Based on these measurements, the specific weight (density, g/cm3) was calculated. Then each bone was cut in the middle of the shaft and the outer and inner diameters were measured both horizontally and vertically. Based on these measurements, the following indicators were calculated: • cortical thickness, • cortical surface, • cortical index. Abstract 11 Bone strength was tested by a three-point bending test. The obtained data enabled the determination of: • bending force (the magnitude of the maximum force at which disintegration and disruption of bone structure occurs), • strength (the amount of maximum force needed to break/crack of bone), • stiffness (quotient of the force acting on the bone and the amount of displacement occurring under the influence of this force). Investigation of changes in physical and biomechanical features of bones during growth was performed on pigs of the synthetic 990 line growing from 15 to 130 kg body weight. The animals were slaughtered successively at a body weight of 15, 30, 40, 50, 70, 90, 110 and 130 kg. After slaughter, the following bones were separated from the right half-carcass: humerus, 3rd and 4th metatarsal bone, femur, tibia and fibula as well as 3rd and 4th metatarsal bone. The features of bones were determined using methods described in the methodology. Describing bone growth with the Gompertz equation, it was found that the earliest slowdown of bone growth curve was observed for metacarpal and metatarsal bones. This means that these bones matured the most quickly. The established data also indicate that the rib is the slowest maturing bone. The femur, humerus, tibia and fibula were between the values of these features for the metatarsal, metacarpal and rib bones. The rate of increase in bone mass and length differed significantly between the examined bones, but in all cases it was lower (coefficient b <1) than the growth rate of the whole body of the animal. The fastest growth rate was estimated for the rib mass (coefficient b = 0.93). Among the long bones, the humerus (coefficient b = 0.81) was characterized by the fastest rate of weight gain, however femur the smallest (coefficient b = 0.71). The lowest rate of bone mass increase was observed in the foot bones, with the metacarpal bones having a slightly higher value of coefficient b than the metatarsal bones (0.67 vs 0.62). The third bone had a lower growth rate than the fourth bone, regardless of whether they were metatarsal or metacarpal. The value of the bending force increased as the animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. The rate of change in the value of this indicator increased at a similar rate as the body weight changes of the animals in the case of the fibula and the fourth metacarpal bone (b value = 0.98), and more slowly in the case of the metatarsal bone, the third metacarpal bone, and the tibia bone (values of the b ratio 0.81–0.85), and the slowest femur, humerus and rib (value of b = 0.60–0.66). Bone stiffness increased as animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. Abstract 12 The rate of change in the value of this indicator changed at a faster rate than the increase in weight of pigs in the case of metacarpal and metatarsal bones (coefficient b = 1.01–1.22), slightly slower in the case of fibula (coefficient b = 0.92), definitely slower in the case of the tibia (b = 0.73), ribs (b = 0.66), femur (b = 0.59) and humerus (b = 0.50). Bone strength increased as animals grew. Regardless of the growth point tested, bone strength was as follows femur > tibia > humerus > 4 metacarpal> 3 metacarpal> 3 metatarsal > 4 metatarsal > rib> fibula. The rate of increase in strength of all examined bones was greater than the rate of weight gain of pigs (value of the coefficient b = 2.04–3.26). As the animals grew, the bone density increased. However, the growth rate of this indicator for the majority of bones was slower than the rate of weight gain (the value of the coefficient b ranged from 0.37 – humerus to 0.84 – fibula). The exception was the rib, whose density increased at a similar pace increasing the body weight of animals (value of the coefficient b = 0.97). The study on the influence of the breed and the feeding intensity on bone characteristics (physical and biomechanical) was performed on pigs of the breeds Duroc, Pietrain, and synthetic 990 during a growth period of 15 to 70 kg body weight. Animals were fed ad libitum or dosed system. After slaughter at a body weight of 70 kg, three bones were taken from the right half-carcass: femur, three metatarsal, and three metacarpal and subjected to the determinations described in the methodology. The weight of bones of animals fed aa libitum was significantly lower than in pigs fed restrictively All bones of Duroc breed were significantly heavier and longer than Pietrain and 990 pig bones. The average values of bending force for the examined bones took the following order: III metatarsal bone (63.5 kg) <III metacarpal bone (77.9 kg) <femur (271.5 kg). The feeding system and breed of pigs had no significant effect on the value of this indicator. The average values of the bones strength took the following order: III metatarsal bone (92.6 kg) <III metacarpal (107.2 kg) <femur (353.1 kg). Feeding intensity and breed of animals had no significant effect on the value of this feature of the bones tested. The average bone density took the following order: femur (1.23 g/cm3) <III metatarsal bone (1.26 g/cm3) <III metacarpal bone (1.34 g / cm3). The density of bones of animals fed aa libitum was higher (P<0.01) than in animals fed with a dosing system. The density of examined bones within the breeds took the following order: Pietrain race> line 990> Duroc race. The differences between the “extreme” breeds were: 7.2% (III metatarsal bone), 8.3% (III metacarpal bone), 8.4% (femur). Abstract 13 The average bone stiffness took the following order: III metatarsal bone (35.1 kg/mm) <III metacarpus (41.5 kg/mm) <femur (60.5 kg/mm). This indicator did not differ between the groups of pigs fed at different intensity, except for the metacarpal bone, which was more stiffer in pigs fed aa libitum (P<0.05). The femur of animals fed ad libitum showed a tendency (P<0.09) to be more stiffer and a force of 4.5 kg required for its displacement by 1 mm. Breed differences in stiffness were found for the femur (P <0.05) and III metacarpal bone (P <0.05). For femur, the highest value of this indicator was found in Pietrain pigs (64.5 kg/mm), lower in pigs of 990 line (61.6 kg/mm) and the lowest in Duroc pigs (55.3 kg/mm). In turn, the 3rd metacarpal bone of Duroc and Pietrain pigs had similar stiffness (39.0 and 40.0 kg/mm respectively) and was smaller than that of line 990 pigs (45.4 kg/mm). The thickness of the cortical bone layer took the following order: III metatarsal bone (2.25 mm) <III metacarpal bone (2.41 mm) <femur (5.12 mm). The feeding system did not affect this indicator. Breed differences (P <0.05) for this trait were found only for the femur bone: Duroc (5.42 mm)> line 990 (5.13 mm)> Pietrain (4.81 mm). The cross sectional area of the examined bones was arranged in the following order: III metatarsal bone (84 mm2) <III metacarpal bone (90 mm2) <femur (286 mm2). The feeding system had no effect on the value of this bone trait, with the exception of the femur, which in animals fed the dosing system was 4.7% higher (P<0.05) than in pigs fed ad libitum. Breed differences (P<0.01) in the coross sectional area were found only in femur and III metatarsal bone. The value of this indicator was the highest in Duroc pigs, lower in 990 animals and the lowest in Pietrain pigs. The cortical index of individual bones was in the following order: III metatarsal bone (31.86) <III metacarpal bone (33.86) <femur (44.75). However, its value did not significantly depend on the intensity of feeding or the breed of pigs.