Layered Gradient Nonwovens of In Situ Crosslinked Electrospun Collagenous Nanofibers Used as Modular Scaffold Systems for Soft Tissue Regeneration

In a versatile modular scaffold system, gradient nonwovens of in situ crosslinked gelatin nanofibers (CGN), fabricated by reactive electrospinning, are laminated with perforated layers and nonwovens of thermoplastic non‐crosslinked biodegradable polyesters. The addition of glyoxal to a gelatin solution in a non‐toxic solvent mixture consisting of acetic acid, ethyl acetate, and water (5:3:2 w/w/w) enables the in situ crosslinking of gelatin nanofibers during electrospinning. The use of this fluorine‐free crosslinking system eliminates the need of post‐treatment crosslinking and purification steps typical for conventional CGN scaffolds. The slowly progressing crosslinking of the dissolved gelatin in the presence of glyoxal increases the viscosity of the gelatin solution during electrospinning so that the average diameter of the crosslinked gelatin nanofibers gradually increases from 90 to 680 nm. During the subsequent lamination process, alternating layers of CGN and polycaprolactone (PCL) nonwovens, produced by 3D microextrusion of micrometer‐sized PCL fibers, are bonded together upon heating above the PCL melting temperature. In contrast to the water‐soluble gelatin nanofibers and the comparatively weak CGN, the CGN/PCL/CGN layered biocomposites are water‐resistant and very robust. In such modular scaffold systems, strength, biodegradation rate, and biological functions can be controlled by varying the type, composition, fiber diameter, porosity, number, and sequence of the individual layers. The CGN/PCL multilayer biocomposites can be cut into any desired scaffold shape and attached to tissue by surgical sutures in order to suit the needs of individual patients.     

Effects of DMBA Preparation on DMBA-Induced Rat Mammary Carcinogenesis

We compared two protocols for 7,12-dimethylbenz[ a ]anthracene (DMBA)-induced mammary carcinogenesis. DMBA (20 mg/ml) was prepared at room temperature or at 60°C and administered by gavage to 50-day-old Sprague-Dawley rats. Two days post-DMBA, mammary epithelial DNA was 32 P-postlabeled. At 12 weeks post-DMBA, tumor DNA was screened for H- ras codon 61 mutations using an enriched polymerase chain reaction (EPCR). The number of in situ carcinomas (3.0 - 2.7 vs. 2.5 - 2.7), invasive carcinomas (1.1 - 1.6 vs. 0.6 - 0.8), and H- ras codon 61 mutations (34 - 13% vs. 23 - 13%) were statistically not different ( p = 0.05) between the groups. The relative adduct levels in mammary organoids were significantly ( p h 0.001) greater in the 60°C (568 - 158) than the room temperature (150 - 130) group. While DMBA-DNA adduct levels differed significantly between these protocols, this did not correlate with significant differences in tumor pathologies or H- ras codon 61 mutations.     

New type of micro-bipolar plate for micro-fuel cells using LIGA technology together with improved and cost-effective electroplating processes for PCBs

A new type of micro-bipolar plate for micro-fuel cells was developed. This micro-bipolar plate was realised using LIGA technology (laser lithography system) together with improved electroplating processes for printed circuit boards (copper, nickel, gold) to produce micro-fuel cells with reduced precious metal loading, increased activity and durability, lower weight and negligible corrosion, and, in addition, lower production cost.     

Interaction of molten aluminum with porous TiB2-based ceramics containing Ti–Fe additives

In this study, the wettability and interaction of porous TiB₂-based composites with liquid aluminum has been investigated. TiB₂ composites were consolidated with Ti and Fe additives using pressureless sintering. The composites show good wettability with respect to molten aluminum. During liquid infiltration, Ti and Fe additives are dissolved. Intermetallic compounds containing Ti, Fe and Al are formed within the penetration depth. Since these phases have melting points higher than the experiment's temperature (960 °C), isothermal solidification takes place during the penetration of molten aluminum. Liquid aluminum does not seem to attack the solid skeleton of the TiB₂ specimens and no signs of swelling or cracking were detected.     

Time-Resolved X-Ray Microtomography Observation of Intermetallic Formation Between Solid Fe and Liquid Al

Time-resolved in situ X-ray tomography combined with scanning electron microscopy was performed on an Al-Fe diffusion system at 973 K (700 °C) to study the formation of the main intermetallic compounds occurring at the interface. After nucleation on the liquid side of the interface, growth occurs in both liquid and solid directions. In the direction of the solid, growth starts with a particular tongue-like feature which then progressively thickens. The thickening is linked to the deformation of the iron matrix during the formation of the intermetallic compound. Growth in the direction of the liquid is slowed down by erosion.     

Physically adjusted neutral detergent fiber system for lactating dairy cow rations. II: Development of feeding recommendations

The objective of this work was to leverage equations derived in a meta-analysis into an ensemble modeling system for estimating dietary physical and chemical characteristics required to maintain desired rumen conditions in lactating dairy cattle. Given the availability of data, responsiveness of ruminal pH to animal behaviors, and the chemical composition and physical form of the diet, mean ruminal pH was chosen as the primary rumen environment indicator. Physically effective fiber (peNDF) is defined as the fraction of neutral detergent fiber (NDF) that stimulates chewing activity and contributes to the floating mat of large particles in the rumen. The peNDF of feedstuffs is typically estimated by multiplying the NDF content by a particle size measure, resulting in an estimated index of effectiveness. We hypothesized that the utility of peNDF could be expanded and improved by dissociating NDF and particle size and considering other dietary factors, all integrated into a physically adjusted fiber system that can be used to estimate minimum particle sizes of TMR and diet compositions needed to maintain ruminal pH targets. Particle size measures of TMR were limited to those found with the Penn State particle separator (PSPS). Starting with specific diet characteristics, the system employed an ensemble of models that were integrated using a variable mixture of experts approach to generate more robust recommendations for the percentage of dietary DM material that should be retained on the 8-mm sieve of a PSPS. Additional continuous variables also integrated in the physically adjusted fiber system include the proportion of material (dry matter basis) retained on the 19- and 8-mm sieves of the PSPS, estimated mean particle size, the dietary concentrations of forage, forage NDF, starch, and NDF, and ruminally degraded starch and NDF. The system was able to predict that the minimum proportion of material (dry matter basis) retained on the 8-mm sieve should increase with decreasing forage NDF or dietary NDF. Additionally, the minimum proportion of dry matter material on the 8-mm sieve should increase with increasing dietary starch. Results of this study agreed with described interrelationships between the chemical and physical form of diets fed to dairy cows and quantified the links between NDF intake, diet particle size, and ruminal pH. Feeding recommendations can be interpolated from tables and figures included in this work.     

War by Photography: Shooting Japanese in Australia’s Pacific War

Characterised by their determination to get close to the action, the Australian combat cameramen of the Second World War made a significant contribution to the evolution of the war photographer into the dynamic figure familiar today. This is especially true of their intimate documentation of the vicious encounter with the Japanese in New Guinea and other islands of the Southwest Pacific, which went beyond professional bravery. A large corps of official photographers shooting for both government and military agencies expressed the racial ideology of a war fought against an opponent who was increasingly loathed as the war progressed. Their pictures of Australian triumphs over the Japanese, including graphic and often deliberately demeaning pictures of dead and captured enemy, reflected the exigencies of wartime propaganda. But they also expanded on a frame of cultural reference derived from decades of anxiety about the threat of invasion by Japan, and reveal an abiding national view of the battlefield as the definitive arena for a contest of rival masculinities. Australia’s war in the Pacific has attracted increasing scholarly and popular attention in recent years. However, the enormous archive of official photographs has been largely ignored, except as a source of illustrative material. This article argues that the archive needs to be read as a collective text in its own right, for the significant insight it provides into Australian cultural as well as military and geopolitical insecurities.     

London and beyond: Taking a closer look at urban energy policy

This paper considers the field of urban energy policy, a neglected yet important topic. Cities account for approximately two-thirds of global primary energy consumption creating significant benefits and costs. As a result there has been growing interest in the contribution of cities to global energy policy issues such as climate change but a number of significant questions remain: e.g. how do energy policy processes differ between national and urban scales, and how can cities contribute most effectively to global policy goals? We present the results of interviews with key stakeholders in London to illustrate some unique features of the urban energy policy cycle. We then take a wider view, proposing a research agenda with three key goals: describing the global variety of urban energy consumption and policy; understanding the resulting diversity in responsibility, vulnerability and capacity; and developing shared procedures and solutions. Tackling these questions is vital if cities are to contribute fully to current energy policy efforts.     

Analysis of the impact of different additives during etch processes of dense and porous low-k with OES and QMS

The focus of this paper is the impact of CF₄ based plasma etch processes with the additives argon and C₄F₈ on material properties and geometrical parameters of etched trenches using dense and porous SiCOH. Argon and C₄F₈ were added to change the radical to ion composition and to shift the carbon to fluorine ratio, respectively. With several techniques, FTIR, spectral ellipsometry and contact angle measurements, modifications in the structure of the materials and their surface conditions were analyzed. To understand the influences of the additives on the plasma conditions, optical emission spectroscopy (OES) and quadrupole mass spectrometry (QMS) were used to estimate the composition of the plasma insitu.For the additive argon, a slightly enhanced etch rate and an increased refractive index due to serious plasma damage for porous SiCOH was observed. At higher Ar flow rates peaks of Si₂O₄H_x clusters in the QMS spectra and increased CO and O lines, measured with OES, indicate a higher sputter yield on the SiCOH network. SEM cross-sections show, that argon has no effect on the sidewall geometry of etched trenches. A higher CH/CN line in the OES spectra indicates an enhanced sputter effect of the SiCN films in via bottoms.For C₄F₈ addition results of spectral ellipsometry show a decreased etch rate and refractive index. Using FTIR the formation of a polymer film on the surface was observed. Higher C₂ lines in the OES spectra are indications of enhanced polymerization efficiency. Finally, the addition of C₄F₈ decreases the etch rate in the trench sidewalls and therewith assumedly the sidewall damage.