Multifunctional hydrogels that promote osteogenic hMSC differentiation through stimulation and sequestering of BMP2

The extracellular environment controls many cellular activities thereby linking external material cues to internal cell function. By better understanding these processes, synthetic extracellular material niches can be tailored to present cells with highly regulated physical and/or chemical cues that promote or suppress selected cell functions. Here, poly(ethylene glycol) (PEG) hydrogels were functionalized with fluvastatin-releasing grafts and growth factor binding heparin domains to enable the dynamic exchange of information between the material and cells from the outside-in and inside-out (i.e., bidirectional signaling). By incorporating a fluvastatin-releasing graft and carefully controlling the dose and temporal release, materials were designed to promote bone morphogenic protein (BMP2) and alkaline phosphatase (ALP) production by human mesenchymal stem cells (hMSCs). When the release of fluvastatin was controlled to occur over 2 weeks, BMP2 and ALP production was increased 2.2-fold and 1.7-fold, respectively, at day 28 compared to hMSCs cultured in the absence of fluvastatin. By introducing a heparin functionality into the gel to sequester and localize the hMSC-produced BMP2, the osteogenic differentiation of hMSCs was further augmented over fluvastatin delivery alone. Osteopontin and core binding factor α1 gene expression was 6-fold and 4-fold greater for hMSCs exposed to fluvastatin in the presence of the heparin functionalities, respectively. These results demonstrate how multifunctional gels that interact with cells in a bidirectional manner can efficiently promote selected cell functions, such as the osteogenic differentiation of hMSCs.     

Recognizing, assessing, and intervening with problems of professional competence.

Working collaboratively, psychologist educators and trainers at the doctoral, internship, and postdoctoral levels; credentialers; practitioners; and students offer 8 proposals for psychologists to consider in recognizing, assessing, and intervening with problems of professional competence in students and practicing professionals. In the proposals, the authors address the following topics: definitions and categories; preparing the system; self-assessment; remediation; diversity; communication across various levels of the system; confidentiality; and ethical, regulatory, and legal underpinnings. They also propose future directions for the assessment of problems in professional competence in both students and practicing psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

BPC – A binary priority countdown protocol

In modern wireless ad hoc networks, with a high speed PHY, every collision means a significant loss of useful bandwidth. In the last few years different binary contention protocols have been introduced to address this problem. In this work we propose a novel binary contention protocol called binary priority countdown (BPC) protocol, whose goal is to reduce collisions as well as contention time. BPC uses a new priority countdown mechanism which exploits the efficiency of binary countdown, but the priority countdown process is not constrained to a single binary countdown round. This way, the priority space is not defined by the length of binary countdown round, like in other binary countdown protocols proposed in the literature, and arbitrary medium access priorities can be decremented through multiple binary countdown rounds if necessary. The ability of a new priority countdown mechanism to count down any priority number without changing the length of a binary countdown round, allows independent management of priority space. This “independence” of priority space introduces new optimization and adaptation possibilities. Collision memory effect is recognized and described. BPC protocol reveals connection between unary, binary and digit contention protocols. All three groups of protocols can now be seen as members of the same class of contention algorithms. Preliminary simulation results are shown.     

Effects of antimicrobial use in agricultural animals on drug-resistant foodborne salmonellosis in humans: A systematic literature review

Controversy continues concerning antimicrobial use in food animals and its relationship to drug-resistant infections in humans. We systematically reviewed published literature for evidence of a relationship between antimicrobial use in agricultural animals and drug-resistant meat or dairy-borne non-typhoidal salmonellosis in humans. Based on publications from the United States (U.S.), Canada, and Denmark from January 2010 to July 2014, 858 articles received title and abstract review, 104 met study criteria for full article review with 68 retained for which data are presented. Antibiotic exposure in both cattle and humans found an increased likelihood of Salmonella colonization, whereas in chickens, animals not exposed to antibiotics (organic) were more likely to be Salmonella positive and those that had antibiotic exposure were more likely to harbor antimicrobial resistant Salmonella organisms. In swine literature, only tylosin exposure was examined and no correlation was found among exposure, Salmonella colonization, or antimicrobial resistance. No studies that identified farm antimicrobial use also traced antimicrobial-resistant Salmonella from farm to fork.     

Density of nafion exchanged with transition metal complexes and tetramethyl ammonium,ferrous, and hydrogen ions: commercial and recast films

The densities of commercial Nafion 117 and cast Nafion 1100 films were determined by the hydrostatic weighing method for films fully exchanged with hexaammineruthenium(III), tris(2,2' bipyridyl)ruthenium(II), tetramethylammonium, ferrous, and hydrogen ions. Films were pretreated in either water or concentrated nitric acid prior to cation exchange. All densities ranged between 1.65 and 2.19 g/cm3. Excluding the proton-exchanged films, the average density is 1.90 +/- 0.14 g/cm3, well in excess of the 1.58 g/cm3 commonly employed for Nafion. The density of acid-pretreated Nafion 1100 was constant at 1.95 +/- 0.03 g/cm3 for all cations except the proton. A simple, empirical model based on the Coulombic interaction between the intercalated cation and the sulfonate sites of the Nafion characterizes density for the commercial Nafion 117 films. A modified version of the model is appropriate for water-treated Nafion 1100. Water content of the films and implications for characterizing modified electrodes are discussed.     

Evaluation of linguistic variations by college students with and without head injuries.

Evaluated the impact of spoken language on listeners by examining the effects of prior head injury, speech register, and active vs passive listening among 56 head-injured (HI) and 55 non-HI undergraduates. Ss rated the degree to which they liked the speaker and also the extent to which groups of negative and positive adjectives described the speaker. There were no differences between HI and non-HI Ss in how much they liked speakers using the normal register, but non-HI Ss liked the motherese speakers more than did HI Ss. Raters liked motherese speakers less when addressed directly than when they were not being directly addressed. Regardless of listener perspective, HI Ss liked motherese speakers less and rated them more negatively than non-HI Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydrocarbon decomposition in alumina membrane: an effective way to produce carbon nanotubes bundles

Carbon nanotubes were synthesised within the pores of an alumina membrane. The membrane had 200 nm diameter pores and 60 microm thickness, and ethylene was used as carbon source. Membrane dissolution by HF results in a bundle of parallel open tubes, aligned without macroscopic defects. The external diameter of the tubes is uniform and there is no evidence of any amorphous carbon. Wall thickness control was obtained by varying the reaction time, length by the thickness of alumina membrane, and external tube diameter by the membrane pore size. Scanning (SEM) and transmission (TEM) electron microscopy, atomic force microscopy (AFM), X-ray diffraction, thermogravimetric analysis (TG) and surface area evaluation by nitrogen adsorption were used for the characterization of membrane and nanotubes.     

A new approach to satellite-based estimation of precipitation over snow cover

Current satellite-based remote-sensing approaches are largely incapable of estimating precipitation over snow cover. This note reports a proof-of-concept study of a new satellite-based approach to the estimation of precipitation over snow-covered surfaces. The method is based on the principle that precipitation can be inferred from the changes in the snow water equivalent of the snowpack. Using satellite-based snow water equivalent measurements, we derived daily precipitation amounts for the northern hemisphere for three snow-accumulation seasons, and evaluated these against independent reference datasets. The new precipitation estimates captured realistic-looking storm events over largely un-instrumented regions. However, the data are noisy and, on a seasonal scale, the amount of precipitation is believed to be underestimated. Nevertheless, current uncertainty in snow measurements, albeit large (50–100%), is still lower than direct precipitation measurements over snow (100–140%) and therefore this approach is still useful. The method will become more feasible as the quality of remotely sensed snow measurements improves.     

Limited communication control

This work in limited communication control is directed towards bringing together classical control theory and communication theoretical issues that are of practical importance in the design of control systems. It is common to “decouple” the communication aspects from the underlying dynamics of a system, as this simplifies the analysis and generally works well for classical models. However, in situations where a single decision maker controls many subsystems over a communication channel of a finite capacity, the computation of control signals and their transmission to each system may take significant amounts of time. To address such cases, we consider a class of discrete-time models that jointly optimize over control and communication goals. Real-world examples where these models play a role include remotely controlled unmanned autonomous vehicles (UAVs), planetary rovers, arrays of microactuators and power control in mobile communication.