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Background Metaphyseal cones provide durable fixation in revision total knee arthroplasty (TKA). However, there is a paucity of data on the outcomes of a new porous cone design. As such, the goal of this study was to analyze the early survivorship in patients undergoing revision TKA with this cone. Methods We retrospectively reviewed 163 revision TKAs with a newly designed porous tibial cone from 2016 to 2018. Mean age was 67 years, and mean body mass index was 33 kg/m2. Minimum follow-up duration was 2 years. Most patients were revised for aseptic loosening (46%), 2-stage periprosthetic joint infection (PJI) reimplantation (28%), or instability (15%). Most were varus-valgus constrained (65%) or hinged (32%) constructs. The majority had hybrid tibial stem fixation (74%). A multivariate Cox regression analysis was used to identify risk factors for reoperation. Results Survivorship free from re-revision for aseptic loosening, any nonmodular revision, and any reoperation was 100%, 96%, and 86% at 2 years, respectively. No patients were revised for aseptic loosening. Six (4%) tibial cones were removed for PJI, one of which was loose. There were 23 reoperations (14%), most commonly for PJI (10%). Multivariate analysis identified PJI reimplantation (hazard ratios [HR] = 4.2, P = .002), males (HR = 2.9, P = .02), and hinged constructs (HR = 2.7, P = .02) as significant risk factors for reoperation. Conclusions In a complex revision TKA cohort with a new highly porous tibial cone, in which most patients received hybrid stem fixation and nonlinked and linked constraint, there was 100% survival free from re-revision for aseptic loosening at 2 years. Longer term follow-up is required.

The uniaxial compressive strength (UCS) of intact rock is one of the most important parameters required and determined for rock mechanics studies in engineering projects. The limitations and difficulty of conducting tests on rocks, specifically on thinly bedded, highly fractured, highly porous and weak rocks, as well as the fact that these tests are destructive, expensive and time-consuming, lead to development of soft computing-based techniques. Application of artificial neural networks (ANNs) for predicting UCS has become an attractive alternative for geotechnical engineering scientists. In this study, an ANN was designed with the aim of indirectly predicting UCS through the serpentinization percentage, and physical, dynamic and mechanical characteristics of serpentinites. For this purpose, data obtained in earlier experimental work from central Greece were used. The ANN-based results were compared with the experimental ones and those obtained from previous analysis. The proposed ANN-based formula was found to be very efficient in predicting UCS values and the samples could be classified with simple physical, dynamic and mechanical tests, thus the expensive, difficult, time-consuming and destructive mechanical tests could be avoided.

Background Tantalum components have gained popularity for the management of Paprosky type IIIA and IIIB defects during revision total hip arthroplasty. Although the use of antiprotrusio cages solely shows suboptimal results, there are certain defects that still require their use. We hypothesized that combining tantalum augments and an antiprotrusio cage would (1) improve radiographic stability, (2) enhance survivorship, (3) decrease complications, and (4) improve clinical outcomes. Methods We retrospectively reviewed 20 patients with Paprosky type IIIA or IIIB defects who underwent revision of the acetabular component with a highly porous tantalum augment and an antiprotrusio cage combination. Preoperative and postoperative radiographs, survivorship free from aseptic component revision, and the Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, and Short Form-36 scores were analyzed. The mean follow-up was 2.8 years. Results At the most recent follow-up, no antiprotrusio cages had migrated and all tantalum augments had radiographic evidence of osseointegration. In addition, only 2 components were revised for aseptic etiologies and only 1 was loose. Both were revised secondary to failures of the inferior flange of the antiprotrusio cage. All clinical outcome scores significantly improved postoperatively. Finally, the risk of major postoperative complications was noted to be 10%. Conclusions In summary, a tantalum augment combined with an antiprotrusio cage in Paprosky IIIA and IIIB defects with divergent anatomy not amenable to a hemispherical socket provides a reliable technique to restore the anatomic hip center and prevent superior migration and provides a bony ingrowth surface. Longer term follow-up is required before the technique is widely adapted. Level of Evidence Level IV, therapeutic studies.

Nanoplasmonic materials play a critical role in surface-enhanced Raman scattering (SERS) because they dictate the electromagnetic (EM) field confinement at the nanoscale and hence the SERS enhancements. These materials can be further engineered to maximize SERS sensitivity, even for analytes with no specific affinity to plasmonic surfaces. In this chapter, we discuss the various types and design strategies of nanoplasmonic materials and their platforms which are employed to boost SERS sensing performance. Four major approaches are outlined: (1) zero-dimensional to three-dimensional hotspot engineering for intense EM field confinement and interparticle plasmonic coupling, (2) physical confinement of liquid analytes on superhydrophobic SERS-active substrates, (3) concentration of gaseous analytes over hotspots using highly porous materials, and (4) development of unconventional nanoplasmonic materials including bimetallic configurations and hybrid systems. Finally, we finish this chapter by discussing current challenges in this research area.

Electrospinning technology is widely used for the generation of nano- or micro-sized fibers, which are capable of producing highly porous materials with high surface-to-volume ratios leading to various applications in algal bioprocesses. While the applications are mainly focused on cultivation and harvesting of algal cells on confined solid spaces, simultaneous processing of immobilized biomass during wastewater treatment has shown great potential in the removal of nitrate, heavy metals, and reactive dyes. Successful fabrication of electrospun materials directly from algal biomass and/or extracts is also possible and holds high promise for improving the sustainability of algal biotechnology. This chapter includes a general introduction of algae-associated electrospun composite materials, a detailed review of their applications in (i) cellular growth and biomass harvesting, (ii) integrated wastewater treatment processes, (iii) fabrication of electrospun fibers from whole algal biomass or algae extracts, and a final conclusion with suggestions regarding future directions of this research field.

With the advent of newer technologies in the electronic and telecommunication sectors, the extent of electromagnetic (EM) pollution is growing at an alarming pace. This is mostly due to the intermixing of EM signals emitted out from electronic modules that are mostly powered by microwave radiations. Hence, there is humungous interest among researches to design and fabricate high-performance microwave-absorbing materials that can address this undesired phenomenon. In this context, plant-derived cellulose nanofibers are considered as one of the most promising bionanomaterials for designing next-generation sustainable microwave absorbers. Nanocellulose can be utilized to fabricate flexible, robust nanopapers and highly porous aerogels that can find potential application as efficient microwave absorbers. This chapter encompasses on various strategies adopted to design and fabricate conducting nanocellulose-based functional constructs by incorporating various 1D and 2D nanostructures. The potential ways to enhance the overall microwave absorption by these shields has also been discussed in detail.

The drastic increase of atmospheric CO2 is the main reason for climate change and the greenhouse effect. The industrial release of CO2 is controlled by liquid sorbent materials which have limitations. Therefore the solid sorbent materials with high surface area, a porous nature, and thermal/mechanical properties receive significant advantages. The strategic synthesis of solid materials is very important to achieve efficient CO2 capture. The choice of synthetic route is based on the nature of the molecular building block. The eco-friendly and one-pot synthesis of solid adsorbent is of strategic importance for building CO2-capture materials. The monomer predesign and postsynthetic modifications also have more importance for the preparation of firm and highly porous solid materials.

Aerogels are specialized highly porous and light nanostructures in which nearly 95% air is trapped by the replacement of solvent in the mesh of material. Biomedical application of aerogels have been well explored as antifungal, antibacterial, antiviral, biosensing and imaging agents, tissue engineering, diagnosis, and regenerative medicines. Different types of molecules like starch, cellulose, hemicellulose, pectin, alginate, chitosan, and chitin have been utilized as aerogel material for biomedical application. The suitable surface properties make them an excellent system for the drug, development, delivery, and release of therapeutic agents at targeted sites. Therefore, recent efforts have resulted in aerogels as an exciting technology for pharmaceutical research and its commercialization.

Geopolymer foams (highly porous materials) have emerged as one of the most exciting materials over the past few years due to their remarkable properties, low cost and green synthesis protocol, enabling their use in various high added-value applications. Review papers on porous geopolymers are uncommon, and the emphasis has been given to materials processing and properties, while the applications were only briefly addressed. This review aims to fill this gap by presenting a comprehensive literature survey and critical analysis of the most recent and exciting research carried out on geopolymer foams. Up to now, these bulk-type (not powders) materials have been mainly considered as thermal and acoustic insulators. However, besides addressing their use as building material, this review also shows that their use in less investigated, but environmentally and economically relevant applications (e.g. bulk-type adsorbents, pH buffering agents and catalysts), is feasible and might ensure performance and technical advantages over their powdered counterparts. The limitations, challenges and future prospects associated with the different applications are presented. This review shows the remarkable potential of geopolymer foams in high added-value applications, far beyond their historical use as Portland cement replacement, which may encourage the widespread technological use of these materials.

This chapter describes the main characteristics and the potential of synthetic bone graft substitutes based on calcium for dental applications. Aspects such as the composition, structure, and processing routes of the different families of materials are reviewed to give the reader a general overview of the different materials. Particular attention will be given to calcium phosphates due to the close chemical resemblance of these materials to the mineral phase of bone. Other families such as calcium sulfates, calcium carbonates, and calcium-containing bioactive glasses are also discussed. The chapter places particular attention on the current and novel strategies based on ion doping (to mimic mineral bone composition), surface functionalization (to mimic the extracellular matrix), and additive manufacturing (to make highly porous yet mechanically stable scaffolds) in the fabrication of the next generation of materials to help accelerate tissue healing and improve bone growth at impaired sites.

Interest in 3D printer technologies for printing personalized medicines has increased manyfold, after FDA approval of the first 3D printed drug product in 2015, using binder jetting 3D printing technology. The process is analogous to a wet granulation process, used in traditional tablet/capsule manufacturing of pharmaceuticals. This process produces highly porous dosage forms that can be administered without water or a sip of water. Unlike other 3D printing processes, this process does not require special polymer(s), and existing FDA approved excipients can be used to prepare dosage forms. This chapter reviews the technical and regulatory aspects of binder jetting 3D printer technology for personalized medicines.

Superabsorbent aerogels are fascinating materials for oil and chemical spillage cleanup. However, the development of an economic and efficient superabsorbent is still highly challenging. In this study, we introduce a novel approach to prepare very low density (0.005 g/cm3), highly porous (>99.6%), economic, reusable, hydrophobic, and magnetic spherical cellulose nanofiber-derived aerogels (i.e., aerobeads) prepared from waste boxboards via a simple freeze-drying procedure. The spherical aerobeads were fabricated easily after dropping a hydrophobized nano-fibrillated cellulose solution containing magnetic Fe3O4 nanoparticles into liquid nitrogen. The aerobeads showed outstanding absorption efficiency for several oils and organic solvents (up to 279 g/g with castor oil) and demonstrated excellent selectivity for absorbing oil from an oil/water mixture. Moreover, they were easily collected by an external magnet, indicating excellent recyclability and reusable for at least 10 cycles while still retaining supreme absorption capacity (up to 101 g/g for diesel oil). This study proposes an economic and novel method for the large-scale preparation of spherical superabsorbent aerobeads, making them a promising candidate for the efficient and sustainable cleaning of oil and chemical spills. Keywords: Freeze-drying, Magnetic, Nanocellulose, Aerobeads, Superabsorbent

The computational and experimental investigation of the fatigue behaviour of AlSi7 aluminium foam is presented in this study. The internal structure of a highly porous specimen was recorded using CT images to enable the subsequent detailed numerical modelling using the finite element method. A new approach for determination of the fatigue life of foam materials was developed, where the standardised approach is very difficult or even not possible to be used. In the proposed approach, several numerical models with different porosity were built and analysed instead of the numerical model, with real porosity of an actual porous structure. Stress-strain results obtained by the numerical analyses of these models were then used in the subsequent fatigue analysis to determine the fatigue lives of the treated porous specimens. Numerical results were compared with the experimental results, which were performed using low cycle fatigue testing under oscillating tensile loading with stress ratio R = 0.1. The developed approach enables the fatigue analyses and prediction of the fatigue lives of various porous structures where a real numerical model is very difficult to build because of its very complicated internal structure.

Facing the growing freshwater scarcity in the 21st century, focused scientific and technological efforts are required to address this grand challenge. A new format of high-flux desalination membranes based on electrospun nanofibrous scaffolds can provide significant energy-saving benefits. Specifically, for reverse osmosis (RO) operations, the formation of nanocomposite barrier layer, containing directed water channels, can overcome the lower permeability limitation of conventional RO membranes. For forward osmosis (FO) and membrane distillation (MD) operations, the highly porous nanofibrous structure also enables much higher flux. In this chapter, we review the current advances of this new class of nanofibrous membranes based on electrospinning technology and its advantages over conventional polymeric membranes.

Functionally graded scaffolds for bone tissue engineering are porous biomaterials in which the porosity changes with a specific gradient in space. The gradation of porosity enables these implants to combine together the best mechanical properties of the denser material with those of the more porous one and the resulting material exhibits performances superior to those of the single constitutive materials. Low-porosity regions provide high mechanical strength, while highly porous regions promote cell adhesion and support cell growth, proliferation, and differentiation. This chapter offers the reader a picture of the hierarchical organization of bone tissue along with a review of functionally graded scaffolds based on bioactive glasses that were developed in recent studies. Furthermore, a case study is reported about the development of simple methods for fabricating bilayered glass-based scaffolds mimicking the interface between cancellous and cortical bone.

In recent years, natural polyetheretherketone (PEEK) cages have been increasingly challenged in the spine fusion market, despite their widespread use, mostly due to concerns about their osseointegration. The natural PEEK once dominated the design space for interbody cages and was the principal implant delivery system for bone morphogenetic protein-2 (BMP). A variety of highly porous metal cage technologies has arisen in the past 5 years. As a result of this challenge, PEEK biomaterials for spinal cages have also evolved to address the clinical concerns about osseointegration. This chapter focuses on the variety of spinal cage applications of PEEK. We begin with an overview of interbody fusion and historical development of the first carbon fiber reinforced (CFR)-PEEK spinal implant, the Brantigan I/F lumbar fusion cage. More recent applications of PEEK biomaterials for cages, such as titanium-coated PEEK cages, are also discussed. The technologies and biomaterials used to construct spinal cages remain a constantly evolving and ongoing topic of debate in the literature.

Three-dimensional (3D) porous silicon carbide (SiC) structures with total porosity in the range of 64–85% are achieved from nanosized SiC powders by filament printing and partial sintering in a spark plasma sintering (SPS) furnace. The effects of the SPS temperature (1500 and 1700 °C) and the addition of oxide sintering aids (7 wt. % YO+AlO) on the porosity of the scaffolds are quantitatively compared. More specifically, hierarchical porosity consisting of meso-pores (< 50 nm) in the struts and open macro-pores (in the range of 500–700 μm) defined by the patterned structure is verified for the 1500 °C SPS treatment. The strength of the structures as a function of the density as well as their cooling profiles, once subjected to rapid heating under a direct flame, are analyzed. By following this easy route, an adaptable family of robust light 3D SiC structures with hierarchical porosity is accomplished., MINECO/FEDER, UE with project MAT2015-67437-R

The effect of scaffold pore size and interconnectivity as well as porosity are undoubtedly crucial factors for most tissue engineering applications. This premise is the basis of worldwide efforts that have been spent to develop increasingly sophisticate fabrication techniques to control the scaffold microarchitecture and build efficient synthetic analogues of extracellular matrix. Among the plethora of techniques developed for this purpose, gas-in-liquid foam templating has emerged as one that conjugates simplicity of the technology involved, use of inert gases as the templating phase (thus avoiding the use of potentially toxic organic solvents), employment of a large variety of biocompatible and often bioactive biopolymers, and obtainment of highly porous and interconnected scaffolds. Experience gained in cell culturing pointed out the main limits of gas-foamed scaffolds, that is the polydispersed nature of both pores and interconnects dimension that cause an uneven distribution of seeded cells within the enclosed 3D space. The awareness of such a limit and increasing demands of more reliable in vitro cellular models stimulated researchers to exploit the potentials offered by microfluidics in the generation of monodisperse gas-in-liquid foam templates. Foam templating through microfluidics gives the opportunity to finely tune the porous texture of the scaffolds, i.e., the dimension of pores and interconnect, eventually independently one from the other, thus responding to the morphological requirements posed by a particular cell type.

This first chapter of the volume largely serves to set the scene for an appraisal of the current status of metal matrix composite (MMCs), with relatively little in the way of detailed information, but extensive cross-referencing to other chapters of the volume, in addition to conventional citation of the literature. The chapter also includes a brief survey of both scientific issues and technological usage of various types of MMC, with some indications of how the landscape has changed since publication of the first issue of Comprehensive Composite Materials in 2000. Particular attention is paid to cermets, which are highly successful in technological terms and are in widespread commercial use: while they should certainly be considered to be type of MMC, they are not specifically covered elsewhere in this volume. Other “special category” MMCs mentioned here include highly porous metals, intermetallic matrix MMCs and graded structure MMCs, although all of these are treated in some detail in other chapters. Finally, there is mention at certain points of the effects of using very fine reinforcement, which is covered elsewhere in the volume only in terms of the processing challenges presented when the fibers or particles concerned are ultra-fine (nanoscale). In fact, while there has been extensive study over the past couple of decades of the potential offered by such reinforcement (in both MMCs and other types of composite system), caveats are identified here concerning expected property combinations, particularly in terms of the toughness of such composites.

Natural gas has received significant attention as a cleaner energy source alternative to gasoline. Natural gas consists of mainly methane (CH 4 ); therefore, efficient storage of CH 4 is essential to utilize natural gas. Porous materials have been widely used to store CH 4 in a safe, efficient and cost-effective way. Among various different types of porous materials, a newly synthesized material family called metal organic frameworks (MOFs) has recently widely studied for CH 4 storage. Several experimental and computational studies showed that MOFs are able to show better CH 4 storage performance than the current benchmark materials such as activated carbons and zeolites due to their highly porous structures. The aim of this chapter is to review the recent advances in CH 4 storage using MOFs. First MOFs are introduced to provide a background about these new nanoporous materials. Both experimental and computational studies performed to evaluate CH 4 storage performance of MOFs were then reviewed. Several approaches to enhance CH 4 uptake capacities of MOFs were also discussed. Finally, current opportunities and challenges of using MOFs for CH 4 storage were addressed.

The three-dimensional fibril-like carbon fiber mat electrode (CFME) decorated with Au nanoparticles (AuNPs) was employed to construct Hg(II) sensing platform for the first time. The highly porous feature of CFME combining the high affinity of AuNPs for mercury endowed the sensing platform with high sensitivity and good reproducibility. Under optimal conditions, the prepared AuNPs/CFME was capable of sensing Hg(II) with a detection limit of 0.1 μg L−1 (S/N = 3) using differential pulse anodic stripping voltammetry (DPASV). Finally, the AuNPs/CFME was successfully demonstrated for the determination of Hg(II) in real water samples with satisfactory results. Keywords: Carbon fiber mat electrode, Gold nanoparticles, Mercury, Anodic stripping voltammetry

Recent advances have been made in the development of smart implant coatings with the potential for controlled actuation in vivo, promoting osseointegration. The design of these coatings is based on the concept of magneto-mechanical actuation of porous ferromagnetic fiber networks. In response to an applied magnetic field, ferromagnetic fibers deform elastically applying strains to in-growing bone tissue. Systematic in vitro experimentation has been conducted to evaluate the biological suitability of a ferritic stainless steel grade for these coatings in two-dimensional sheets and a three-dimensional, highly porous network. These studies have considered critical biological parameters such as responses of bone and inflammatory cells. A discussion of these in vitro studies is presented in the current review along with a perspective of current magneto-mechanical actuation experiments with these materials.

6 págs.; 8 figs., A novel method for the formation of amorphous ice involving matrix sublimation has been developed. A CO-rich CO:HO mixed ice was deposited at 8–10 K under ultra-high vacuum condition, which was then allowed to warm. After the sublimation of matrix CO at 35 K, amorphous ice remained. The amorphous ice formed exhibits a highly porous microscale texture; however, it also rather exhibits a density similar to that of high-density amorphous ice formed under high pressure. Furthermore, unlike conventional vapor-deposited amorphous ice, the amorphous ice is stable up to 140 K, where it transforms directly to cubic ice Ic. 2016 Elsevier B.V. All rights reserved., This study was supported by the Grant for the Joint Research Program of the Institute of Low Temperature Science, Hokkaido University, I-link-1027 project from CSIC, JSPS KAKENHI (Grant Number 25247086), and MEXT KAKENHI (Grant Number 25108002).

Electrospinning is a versatile scaffold-synthesis method to produce highly porous structures composed of extracellular matrix resembling nano- and microfibers from a variety of polymeric materials. This chapter will discuss electrospinning as a suitable method to create biomimetic-engineered cartilage tissue. Additionally, it will explore the current techniques, applications, and limitations in electrospun scaffolds for the regeneration of diseased or damaged cartilage.

Genetic gains in quality traits were assessed in grain samples from 4 field experiments involving 16 bread wheat varieties representative of those most widely cultivated in Spain during the 20th century. The allelic composition at three glutenin loci (Glu-A1, Glu-B1, and Glu-D1) was obtained by PCR-based DNA markers and published references. From 1930 to 2000 grain protein content decreased by −0.030% y−1, or in relative terms by −0.21% y−1, but the protein produced per hectare increased by 0.39% y−1. Alveographic tests revealed significant changes in dough rheological properties. Dough strength (W) and tenacity (P) increased at relative rates of 1.38% y−1 and 0.99% y−1, respectively, while dough extensibility (L) decreased by −0.46% y−1, resulting in an increase of 1.45% y−1in dough equilibrium (P/L). The rise in protein quality could be related to the replacement of the null allele by subunits 1 or 2* at Glu-A1 and the prevalence of subunits 7 + 8 and 5 + 10 at Glu-B1 and Glu-D1 loci, respectively, in the most recent varieties. Dough extensibility was affected by water input during the crop cycle, this relationship being partially explained by the presence of the 5 + 10 HMW glutenin subunit. Fermentation tolerance was improved in the most modern varieties. Collapse during fermentation was avoided only in doughs with a W ≥ 159 J × 10−4 and a P/L ≥ 0.56 mm H2O mm−1, levels achieved by most of the modern varieties. The over-strong and unbalanced rheological properties of some modern varieties resulted in highly porous doughs, and no clear advances in dough maximum height during fermentation were attained. This study was partially funded by the Spanish National Institute for Agriculture and Food Research and Technology (INIA) [RTA2004-058-C04 and RTA2009-061-C03] and Spain’s Inter-Ministerial Commission for Science and Technology (CICYT) [AGL-2009-11187]. The Centre UdL-IRTA is part of the Centre CONSOLIDER INGENIO 2010 on Agrigenomics funded by the Spanish Ministry of Education and Science. M. Sanchez-Garcia was a recipient of a PhD grant from INIA.

WOS:000340323300014; International audience; Microorganisms from damp indoor environments are known to be one of the main causes of the degradation of indoor air quality and can be serious health hazards to occupants because of the production of airborne particles. Surfaces of building materials (plasterboard, mortar, etc.) are generally highly porous and rough. In damp environments, these materials can provide an environment favourable to proliferation and growth of microorganisms. Sampling of microbial communities on building materials, in addition to air sampling, is thus necessary to evaluate microbial proliferation indoors. The present paper aims to (i) summarise and compare the different methods used for sampling and analysing microbial growth on building materials and (ii) make a synthesis on the colonising microbial communities and the building materials parameters (humidity, chemical composition, pH, etc.) affecting their growth. With regards to methods, our investigations focused exclusively on studies dealing with building materials. When available, studies comparing the efficiency of methods on building materials were discussed. In-situ sampling campaigns were reviewed and the microorganisms identified on building materials were listed. Factors determining bio-receptivity of materials were also examined on the basis of studies performed on various types of materials (including building materials). The microorganisms the most frequently detected on indoor building materials are (i) fungi genera Cladosporium, Penicillium, Aspergillus and Stachybotrys, and (ii) Gram negative bacteria and mycobacteria. Some correlations between microbial genera/species and the type material can also be outlined. The water activity, the chemical composition, the pH and the physical properties of surfaces are parameters influencing microbial growth on materials. The particular behaviour of porous materials in terms of water sorption and the effect of water on microbial proliferation are underlined. In the future, the standardisation of methods for sampling, analysis and laboratory testing will be helpful in the assessment of microbial proliferation in building materials. Moreover, investigations on the impact of the material's mineralogy and its surface properties on growth will be necessary for a better understanding and predicting of microbial proliferation on these substrates.

The extracellular matrix (ECM) is a dynamic and heterogeneous environment that controls many aspects of cell behavior. Not surprisingly, many different approaches have focused on creating model substrates that recapitulate the biomolecular, topographical, and mechanical properties of the ECM for in vitro studies of cell behavior. This chapter details a general, versatile method for the spatially controlled deposition of multiple biomolecules onto both planar and topographically complex support structures with micrometer resolution. This approach is based upon the well-understood photochemical UV crosslinking of benzophenone (BP) to solution-phase biomolecules. This is a molecularly general strategy that can be utilized to immobilize biomolecules onto any surface prefunctionalized with BP. Examples described herein include modification of planar and corrugated glass substrates as well as collagen–glycosaminoglycan biomaterials configured either as highly porous scaffolds or nonporous membranes with a variety of biomolecular targets, including proteins, glycoproteins, and carbohydrates.

Since the introduction of suitable, highly porous supports and later nonporous and monolithic supports, chromatography has been an indispensible method for protein separations on the analytical and preparative scales. The most frequently used methods for protein chromatography are ion exchange, reversed phase, hydrophobic interaction chromatography, chromatography on hydroxyapatite and different types of affinity, and pseudo-affinity chromatography. Because of the use of organic solvents during the separation in reversed-phase chromatography, denaturation and loss of biological activity frequently occurs, and this method is less suitable for separation of biologically active, therapeutic proteins. Chromatography on monolithic supports and chromatography in the displacement mode offer additional opportunities for fast, highly effective separation of proteins on both the analytical and preparative scales.

Current research trends on nanocomposite materials for tissue engineering, including strategies for the fabrication of nanocomposite scaffolds with highly porous and interconnected pores, are presented. The results of in-vitro cell culture, used to analyzed the cell–scaffold interaction considering the colonization of mesenchymal stem cells and degradation of the scaffolds in-vitro, are also discussed.

[EN] Highly porous carbons have been prepared by the chemical activation of two mesoporous carbons obtained by using hexagonal- (SBA-15) and cubic (KIT-6)-ordered mesostructured silica as hard templates. These materials were investigated as sorbents for CO2 capture. The activation process was carried out with KOH at different temperatures in the 600–800 °C range. Textural characterization of these activated carbons shows that they have a dual porosity made up of mesopores derived from the templated carbons and micropores generated during the chemical activation step. As a result of the activation process, there is an increase in the surface area and pore volume from 1020 m2 g−1 and 0.91 cm3 g−1 for the CMK-8 carbon to a maximum of 2660 m2 g−1 and 1.38 cm3 g−1 for a sample activated at 800 °C (KOH/CMK-8 mass ratio of 4). Irrespective of the type of templated carbon used as precursor or the operational conditions used for the synthesis, the activated samples exhibit similar CO2 uptake capacities, of around 3.2 mmol CO2 g−1 at 25 °C. The CO2 capture capacity seems to depend on the presence of narrow micropores (, The financial support for this research work provided by the Spanish MCyT (MAT2008-00407) is gratefully acknowledged. P. V-V. and M. S. thank the Spanish MCyT for the award of a grant (JAE-Predoc) and a Postdoctoral Mobility contract, respectively.

Mesoporous bioactive glass (MBG) is a new class of biomaterials with a well-ordered nanochannel structure, whose in vitro bioactivity is far superior than that of non-mesoporous bioactive glass (BG); the material's in vivo osteogenic properties are, however, yet to be assessed. Porous silk scaffolds have been used for bone tissue engineering, but this material's osteoconductivity is far from optimal. The aims of this study were to incorporate MBG into silk scaffolds in order to improve their osteoconductivity and then to compare the effect of MBG and BG on the in vivo osteogenesis of silk scaffolds. MBG/silk and BG/silk scaffolds with a highly porous structure were prepared by a freeze-drying method. The mechanical strength, in vitro apatite mineralization, silicon ion release and pH stability of the composite scaffolds were assessed. The scaffolds were implanted into calvarial defects in SCID mice and the degree of in vivo osteogenesis was evaluated by microcomputed tomography (μCT), hematoxylin and eosin (H&E) and immunohistochemistry (type I collagen) analyses. The results showed that MBG/silk scaffolds have better physiochemical properties (mechanical strength, in vitro apatite mineralization, Si ion release and pH stability) compared to BG/silk scaffolds. MBG and BG both improved the in vivo osteogenesis of silk scaffolds. μCT and H&E analyses showed that MBG/silk scaffolds induced a slightly higher rate of new bone formation in the defects than did BG/silk scaffolds and immunohistochemical analysis showed greater synthesis of type I collagen in MBG/silk scaffolds compared to BG/silk scaffolds.

Publisher Summary This chapter provides an overview of the hypercrosslinked polymers. Hypercrosslinked polystyrene networks owe their extraordinary structure and remarkable properties to the basic principle of their preparation; the latter consists of intensive bridging of strongly solvated polystyrene chains with conformationally rigid links. The formation process of a hypercrosslinked polystyrene network is quite different. It starts with strongly solvated polystyrene chains, rather than monomers. It is very important to emphasize here that two basic factors prevent the starting homogeneous polymer solution (or gel) from micro-phase separation during the post-crosslinking process. First, long polymeric chains extend through the initial solution (or gel) and remain strongly solvated over the entire period of network formation. Second, the crosslinking bridges emerge throughout the volume of the reacting system with a statistically uniform distribution. Hypercrosslinked polystyrene networks not only have unique set of physico-chemical properties but they also acquire great practical importance as excellent adsorbing materials. Indeed, one of the basic distinguishing features of the single-phase highly porous hypercrosslinked matrix is that its polymeric chains are separated by homogeneously distributed, long, and rigid bridges, better to say, struts, and therefore remain permanently exposed to gaseous or liquid environment. Being deprived of close contacts to one another, these chains generate a strong uncompensated force field. Hypercrosslinked polystyrene attracts and retains a wide variety of organic compounds from the surrounding medium and concentrates them in the interior of the network.

Fibrous materials are suitable for applications involving filtration and separation because they have large surface areas and highly porous structures. Medical filters made from porous hollow fibers have important applications in providing long-term or temporary extracorporeal supports for failed human organs, such as the kidney, liver, lungs and pancreas. This chapter introduces the main types of polymers and structures for hollow fiber bioreactors, and applications of these bioreactors. The characterization and evaluation methods for these medical filters are also discussed.

Flooded lead–acid batteries (LAB) have been used for more than 140 years in various applications, which include automotive, traction, and stationary. Although valve-regulated lead–acid batteries have gained significant market shares over the past decades, the flooded design is still the major part of all manufactured LAB. The essential components of a LAB are the positive and negative electrodes (grids and active materials), the electrolyte (diluted sulfuric acid), the highly porous separators between the plates, the current collector system (top bars, terminals, and intercell connectors for block batteries), and the container with the lid. Flat plate design is used virtually for all negative and most of the positive electrodes. However, there are also batteries with positive plates of the tubular or Plante design. Over the decades, there have been many improvements on the flooded types, which include the reduction or even elimination (for certain applications) of antimony in the grid alloys, the use of modern plastic materials for container and lid, inter-cell connection for block batteries rather than connecting cells outside the lids, separators with higher porosity, lighter and thinner grids, alloys with lower corrosion rate, and active materials with better utilization and cycling performance.

Publisher Summary This chapter presents the fundamentals of continuum micromechanics. This mathematical theory allows for explanation of mechanical interactions at the micro structural observation scales of the Hydroxyapatite (HA) biomaterials. In this way, macroscopic mechanical properties can be linked to micro structural characteristics. The chapter develops a continuum micromechanical concept for elasticity and strength of mono-porosity biomaterials made of hydroxyapatite. It verifies the validity of these micromechanics models for numerous different porous HA biomaterials, on the basis of physically and statistically independent morphological and mechanical tests. It also shows how to extend the developed theories to HA biomaterials with a hierarchical structure, that is, with a double-porosity. Such biomaterials have recently been introduced for tissue engineering purposes. The models will show the role of micro- and macro-porosity on the stiffness and strength properties of highly porous tissue engineering scaffolds.

Publisher Summary Among the volcanic rocks from Azores Islands, trachyte stones have been preferentially used through centuries in many monument facades because of their color and softness. After a few centuries, these stones show remarkable decaying. This chapter describes the study conducted to compare the trachyte stones from quarries and monument to point out the similarities and differences in their petrophysical and chemical characteristics and to determine the decay phenomenon. Angra do Heroismo Cathedral in Terceira Island and Misericordia Church in Sao Miguel Island were the monuments selected for the study on degradation causes and mechanisms. The same methodology was applied to quarry and monument samples from both Islands by using petrographic, mineralogical, chemical, and petrophysical techniques. The Well-marked differences were noticed among the trachytes from Sao Miguel and Terceira Islands; but within each island, outcrops or the monument building stones showed several similarities. Some textural aspects observed in the field showed some variability; the stones had a pore-type porosity of genetic nature. The values of porosity accessible to water were very high for monument samples and higher than the values for quarry samples. The samples of Misericordia Church showed a high porosity, dominated by large pores. It was concluded that these highly porous trachyte materials are susceptible to degradation, namely by salt crystallization mechanisms.

A hydrocyclone treating an itabirite iron ore was sampled, characterized in detail using modern image analysis techniques and modeled. Some of the most interesting results from this investigation were: the itabirite studied is highly porous; this property may be advantageous in direct reduction applications; two types of porosity are present; one is macroscopic and the other microscopic; the micro-pores in this itabirite are interconnected. Porosity liberation in the size range studied is associated to the macro pores; the process of liberation in this itabirite is quick, probably aided by liberation by detachment; the regimen inside the hydrocyclone is closer to turbulent than it is to laminar regimen; the density of the slurry in the separation zone must be used instead of the density of the liquid. It is anticipated that lateritic iron ores in general may present significant porosity, and this must be taken into consideration when evaluating image analysis results from this type of ores.

This first chapter of the volume largely serves to set the scene for an appraisal of the current status of metal matrix composite (MMCs), with relatively little in the way of detailed information, but extensive cross-referencing to other chapters of the volume, in addition to conventional citation of the literature. The chapter also includes a brief survey of both scientific issues and technological usage of various types of MMC, with some indications of how the landscape has changed since publication of the first issue of Comprehensive Composite Materials in 2000. Particular attention is paid to cermets, which are highly successful in technological terms and are in widespread commercial use: while they should certainly be considered to be type of MMC, they are not specifically covered elsewhere in this volume. Other “special category” MMCs mentioned here include highly porous metals, intermetallic matrix MMCs and graded structure MMCs, although all of these are treated in some detail in other chapters. Finally, there is mention at certain points of the effects of using very fine reinforcement, which is covered elsewhere in the volume only in terms of the processing challenges presented when the fibers or particles concerned are ultra-fine (nanoscale). In fact, while there has been extensive study over the past couple of decades of the potential offered by such reinforcement (in both MMCs and other types of composite system), caveats are identified here concerning expected property combinations, particularly in terms of the toughness of such composites.

Publisher Summary High-performance liquid chromatography (HPLC) has become the method of choice for the separation and purification of polypeptides. The advantages of HPLC over more conventional chromatographic techniques are many, including fast separation times, high recoveries, improved resolution, and greater sensitivity. The technique is based on the highly resolutive separations that can be achieved using uniform micro-particulate supports. These highly porous supports are selectively derivatized to suit the chromatographic mode required. The separation of polypeptides has proved difficult, as they are complex molecules that vary in size, charge, solubility, and conformation. The development and application of reversed-phase (RP)–HPLC has overcome these difficulties. This chapter focuses on the development of separation strategies for the purification and characterization of polypeptides, emphasizing on RP–HPLC techniques. The chapter also discusses some other HPLC strategies, especially in combination with RP–HPLC, for the isolation of polypeptides, particularly, from complex matrices.

This paper describes the preparation and characterization of a fixed bed catalytic reactor based on sintered metals. A silicone elastomer solution is used to cover the internal surface of the sintered metal with a highly porous continuous silica layer, on which the active component can be applied. These reactors can be used for processes in which a uniform temperature within the catalyst bed is essential.

It has now been demonstrated that soft rock is a suitable medium for underground storage. The first example was at Petit-Couronne site, and a further development and full confirmation has just been completed in chalk at Vexin in France, with a capacity of 130 000m3 (818 000 Bbls) for liquid propane. Thorough investigations of the geological and geotechnical context of this weak, highly porous material, produced an elegant design in which the refined shapes of 47m2 (506 sq.ft) storage galleries ensures perfect stability without support, while at the same time ensuring there would be no disturbance to water-table. With proper investigation and design, underground storage in what was hitherto considered poor engineering rock of the type commonly found in the sedimentary basins in which many of the world's major towns are built is now an attractive proposition. Le stockage souterrain est desormais possible en roches tendres ; il a ete realise dans la craie sur le site du Vexin un stockage de 130 000 m3 de propane liquefie; un autre stockage avait ete anterieurement realise a Petit-Couronne. L'etude geologique et geotechnique du site et de la craie de faible resistance et forte porosite, a permis de projeter et realiser des galeries de 47m2 de section, de definir et surveiller les conditions hydrogeologiques, et d'obtenir une stabilite parfaite. Moyennant des etudes appropriees des materiaux et des sites, le stockage souterrain apparait possible, attractif dans des terrains de faibles caracteristiques mecaniques, comme le sont parfois les terrains sedimentaires de grands bassins oo sont situees des agglomerations importantes. Es ist nun moglich, Untertagespeicher in weichem Gestein zu schaffen. 130 000 m3 verflussigten Propangases wurden in der Kreide des Vexins gespeichert; fruher war ein anderer Untertagespeicher bei Petit-Couronne geschaffen worden. Die geologische und geomechanische Studie des Ortes sowie der durch geringe Festigkeit und hohe Porositat gekennzeichneten Kreide hat erlaubt, Stollen von 47m2 Querschnitt zu planen und auszubrechen; dabei wurden die hydrogeologischen Bedingungen bestimmt und uberwacht, und eine perfekte Stabilitat ergab sich daraus. Fuhrt man angepasste Studien der Materialen und der Orte, so erscheinen Untertagespeicher in durch geringe mechanische Eigenschaften gekennzeichneten Gesteinen als moglich und attraktiv; solche Gesteine findet man manchmal in grossen sedimentaren Becken, wo Grosstadte liegen.

Direct and indirect evidence for the nature of lunar surface materials is examined and compared with theoretical predictions. Conclusions are then drawn concerning the most probable character of these materials. It is concluded that the lunar surface is covered with a layer of rubble of highly variable thickness and block size. The rubble in turn is mantled with a layer of highly porous dust which is thin over topographic highs, but thick in depressions. The dust has a complex surface and significant, but not strong, coherence.