An Organoid for Woven Bone

Bone formation (osteogenesis) is a complex process in which cellular differentiation and the generation of a mineralized organic matrix are synchronized to produce a hybrid hierarchical architecture. To study the mechanisms of osteogenesis in health and disease, there is a great need for functional model systems that capture in parallel, both cellular and matrix formation processes. Stem cell-based organoids are promising as functional, self-organizing 3D in vitro models for studying the physiology and pathology of various tissues. However, for human bone, no such functional model system is yet available. This study reports the in vitro differentiation of human bone marrow stromal cells into a functional 3D self-organizing co-culture of osteoblasts and osteocytes, creating an organoid for early stage bone (woven bone) formation. It demonstrates the formation of an organoid where osteocytes are embedded within the collagen matrix that is produced by the osteoblasts and mineralized under biological control. Alike in in vivo osteocytes, the embedded osteocytes show network formation and communication via expression of sclerostin. The current system forms the most complete 3D living in vitro model system to investigate osteogenesis, both in physiological and pathological situations, as well as under the influence of external triggers (mechanical stimulation, drug administration).     

Determination of nano-roughness of carbon fibers by atomic force microscopy

We present a novel approach to determine the surface roughness on varying scales using atomic force microscopy data. The key factor is to find a suitable background correction for the desired scale. Using the example of the surface of sized and unsized high-tenacity carbon fibers, we present an easy method to find backgrounds for widely varying scales and to evaluate respective topography and surface roughness with the same lateral resolution as the microscope itself. The analysis is done by subtracting a tunable background from the respective height data. By choosing an appropriate background to investigate the surface topography of a carbon fiber on a nm-scale, only small nano-structures with a width of around 20 nm remain after the background subtraction. Evaluating the mean roughness R _a of these nano-structures, sized carbon fibers show an overall value of around 0.1 nm while unsized carbon fibers a value of around 0.4 nm. Total background corrected height analysis shows an even distribution of these nano-structures along the fibrils of the unsized fibers, whereas for the sized fibers the nano-structures are not present. The presented method allows analysis and visualization of the distribution of nano-structures on a carbon fiber surface for the first time. This feature is used to visualize the distribution of the sizing and can further be used to investigate the influence of different production parameters on the fiber topography or to evaluate the contribution of mechanical interlocking to the interfacial strength.     

Studies on the Structural,Morphological, Optical,and Magnetic Properties of α-Fe2O3 Nanostructures by a Simple One-Step Low Temperature Reflux Condensing Method

Uniform hematite (α-Fe₂O₃) nanoparticles have been successfully synthesized through a simple one-step low temperature reflux condensing method which requires no surfactants or templates. The crystallite size was calculated by using Debye–Sherrer formula, and it showed the range of 4–27 nm. The lattice parameters of the samples were measured by Rietveld analysis. The morphology of the products was studied by high resolution scanning electron microscopy (HR-SEM), and it was confirmed by high resolution transmission electron microscopy (HR-TEM). The HRTEM images exhibit the well defined lattice fringes of α-Fe₂O₃ particles that confirm their high crystallinity. The formation of pure α-Fe₂O₃ was further confirmed by using energy dispersive X-ray (EDX) analysis. The optical properties and the bandgap energy were measured by UV-Visible diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. The bandgap energy was measured by using Kubelka–Munk method, and the value was found to be 2.26 eV. Magnetic hysteresis (M–H) loops revealed that the as-prepared α-Fe₂O₃ samples displayed ferromagnetic behavior. These results show that the prepared hematite possess good magnetic properties.     

The Acrylation of Glycerol: A Precursor to Functionalized Lipids

With the objective of expanding the number of functionalized lipids available, the reactive vinyl group of acrylic acid was introduced to triacylglycerol by esterification of glycerol. Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K₂O as catalyst. 2 g (21.7 mmol) glycerol, 11.3 g (65.4 mmol) decanoic acid, 6.2 g (86.1 mmol) acrylic acid, 60 ml hexane, and 400 mg K₂O were added to 300-ml closed stainless steel reactor and maintained at 200 °C for 5 h. The resulting product, designated DDA, was isolated at about 40% yield based on the acylglycerol products. The other products included tridecanoylglycerol, diacryloyldecanoylglycerol, and the diacylglycerols of these acids. DDA was then converted to functionalized lipids by the Michael addition and Heck reaction. The Michael addition of thiophenol and 4-bromothiophenol yielded the corresponding linear thioethers whereas and Heck reaction products from bromobenzene and bromoanisole yielded triacylglycerols containing trans-cinnamic acid and trans-(4-methoxy)cinnamic acid, respectively.     

Approaches to resource reservation for migrating real-time sessions in future mobile wireless networks

This paper presents two novel frameworks for session admission control and resource reservation in the context of next generation mobile and cellular networks. We also devised a special scheme that avoids per-user reservation signaling overhead in order to meet scalability requirements needed for next generation multi-access networks. The first proposal, Distributed Call Admission Control with Aggregate Resource Reservation (VR), uses mobility prediction based on mobile positioning system location information and takes into account the expected bandwidth to be used by calls handing off to and from neighboring cells within a configurable estimation time window. In conjunction, a novel concept called virtual reservation has been devised to prevent per-user reservation. Our second proposal, Local Call Admission Control and Time Series-based Resource Reservation, takes into account the expected bandwidth to be used by calls handed off from neighboring cells based only on local information stored into the current cell a user is seeking admission to. To this end, we suggest the use of two time series-based models for predicting handoff load: the Trigg and Leach (TL), which is an adaptive exponential smoothing technique, and Autoregressive Integrated Moving Average (ARIMA) that uses the Box and Jenkins methodology. It is worth to emphasize that the use of bandwidth prediction based on ARIMA technique still exist for wireless networks. The novelty of our approach is to build an adaptive framework based on ARIMA technique that takes into account the measured handoff dropping probability in order to tuning the prediction time window size so increasing the prediction accuracy. The proposed schemes are compared through simulations with the fixed guard channel (GC) and other optimized dynamic reservation-based proposals present in the literature. The results show that our schemes outperform many others and that the simpler local proposal based on TL can grant nearly similar levels of handoff dropping probability as compared to those from more the complex distributed approach.     

Australia's housing choices: Retrospect and prospect

This article identifies issues around the Auckland Region's strategy for urban intensification and discusses the ensuing policy implications. Medium density housing forms an important element of the strategy for growth management. Implications for its success are primarily drawn from research into a major housing development in Waitakere City. It is argued that for ideological, political and technical reasons the strategy could be easily undermined. The article also suggests that something of a paradigm shift is underway in urban planning.     

One-pot synthesis of gelatin-based,slow-release polymer microparticles containing silver nanoparticles and their application in anti-fouling paint

Gelatinous polymer matrix microparticles containing silver nanoparticles (AgNPs) were prepared by a novel method to obtain quasi non-swelling anti-fouling paint additives with slow-release characteristics. A w/o type dispersion were elaborated with the aqueous phase of gelatin, urea, silver-nitrate and formaldehyde dispersed in linseed oil. Gelatin was cross-linked by formaldehyde, together with urea for limiting the swelling of the product. Silver-nitrate was reduced with the assistance of gelatin and formaldehyde into homogenously dispersed AgNPs. The microparticles and embedded AgNPs were visualized by scanning and transmission electronmicroscopy. Encapsulated AgNPs with ∼18 nm crystallite size were identified by X-ray powder diffraction. Characterization of gelatin–urea–formaldehyde polymer matrices was carried out by attenuated total reflectance FTIR spectroscopy. Silver dissolution from microparticles and paints with AgNP-containing microparticles was measured by inductively coupled plasma spectrometer and resulted in highly sustained release, compared to unmodified gelatin microparticles and paints containing uncapsulated silver salts. A 7-month-long fouling experiment run in natural sweetwater media showed that solvent-based acrylic paint with AgNPs-containing gelatinous microparticles as additives offered resistance against biofouling at low Ag-release ratio.     

Resisting tempting foods and smoking behavior: Implications from a self-control theory perspective.

Objective: Individuals may desire to diet or restrain from eating certain foods while attempting to quit smoking out of concern for weight gain. However, previous research and clinical tobacco treatment guidelines suggest that concurrent dieting may undermine attempts to quit smoking. The current study applied the self-control strength model, which posits that self-regulation relies on a limited strength that is consumed with use, to test whether resisting tempting sweets would lead to a greater likelihood of subsequent smoking. Design: Participants were 101 cigarette smokers randomly assigned to resist eating either from a tempting plate of sweets or from a plate of less tempting vegetables. All participants were then given a 10-min recess. Main Outcome Measures: Whether participants smoked during the break, measured with a breath carbon monoxide sample, served as the primary dependent variable. Results: As predicted, participants who resisted sweets were more likely to smoke during the break (53.2%) than those who resisted vegetables (34.0%), χ2(1, N = 101) = 3.65 p     

Creative mythconceptions: A closer look at the evidence for the "mad genius" hypothesis.

Many people believe that the “mad genius” notion, which has been a favorite cultural fixture for centuries, is based on established scientific fact. Much of the evidence for the connection between great creativity and great pathology, particularly affective disorder, comes from the writings of psychiatrists Nancy Andreasen and Arnold K. Ludwig and psychologist Kay Redfield Jamison. For two decades, their studies and books have been widely referenced in both the popular and professional press without critique or comment and often without much detail, suggesting that few people have spent much time with the originals. This article examines their most influential works, encouraging readers to evaluate this evidence for themselves, because the author believes that many of their claims have had unfortunate implications for the perception of creativity and the credibility of psychological research in general. The author considers the inherent difficulties of generating any scientific findings in this area, and concludes by discussing the signs of a hopeful trend to celebrate, rather than pathologize, people with exceptional gifts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Channel Models for Medical Implant Communication

Information regarding the propagation media is typically gathered by conducting physical experiments, measuring and processing the corresponding data to obtain channel characteristics. When this propagation media is human body, for example in case of medical implants, then this approach might not be practical. In this paper, an immersive visualization environment is presented, which is used as a scientific instrument that gives us the ability to observe RF propagation from medical implants inside a human body. This virtual environment allows for more natural interaction between experts with different backgrounds, such as engineering and medical sciences. Here, we show how this platform has been used to determine channel models for medical implant communication systems.