Investigation of cancer cell behavior on nanofibrous scaffolds

Tissue engineering and the use of nanofibrous biomaterial scaffolds offer a unique perspective for studying cancer development in vitro. Current in vitro models of tumorigenesis are limited by the use of static, two-dimensional (2D) cell culture monolayers that lack the structural architecture necessary for cell-cell interaction and three-dimensional (3D) scaffolds that are too simplistic for studying basic pathological mechanisms. In this study, two nanofibrous biomaterials that mimic the structure of the extracellular matrix, bacterial cellulose and electrospun polycaprolactone (PCL)/collagen I, were investigated as potential 3D scaffolds for an in vitro cancer model. Multiple cancer cell lines were cultured on each scaffold material and monitored for cell viability, proliferation, adhesion, infiltration, and morphology. Both bacterial cellulose and electrospun PCL/collagen I, which have nano-scale structures on the order of 100-500 nm, have been used in many diverse tissue engineering applications. Cancer cell adhesion and growth were limited on bacterial cellulose, while all cellular processes were enhanced on the electrospun scaffolds. This initial analysis has demonstrated the potential of electrospun PCL/collagen I scaffolds toward the development of an improved 3D in vitro cancer model.     

Upper and Lower Bounds for Selection on the Mesh

A distance-optimal algorithm for selection on the mesh has proved to be elusive, although distance-optimal algorithms for the related problems of routing and sorting have recently been discovered. In this paper we explain, using the notion of adaptiveness, why techniques used in the currently best selection algorithms cannot lead to a distance-optimal algorithm. For worst-case inputs we apply new techniques to improve the previous best upper bound of 1.22n of Kaklamanis et al. [7] to 1.15n . This improvement is obtained in part by increasing the adaptiveness of previous algorithms. Received May 25, 1995; revised June 1, 1996.     

Role of psychoanalytic merging fantasies in systematic desensitization: A rigorous methodological examination.

L. H. Silverman et al (see record 1974-32983-001) purported to document that the effectiveness of systematic desensitization resides partially in its activation of unconscious merging fantasies. Their procedures, however, suggest the existence of serious threats to the internal, external, and statistical conclusion validity of this contention. Presented is a methodologically rigorous replication and extension of the investigation. 46 bug-phobic women participated in 4 therapy sessions. A variant of desensitization was employed in which viewing verbal stimuli presented subliminally was substituted for muscle relaxation. Ss in 3 treatments viewed stimuli that, according to psychoanalytic theory, should (a) decrease fear and behavioral avoidance, (b) increase anxiety, or (c) have no effect on fear of insects. Contrary to predictions derived from the theory, Ss in all conditions manifested significant improvement on behavioral approach, self-reported distress, and behaviorally rated anxiety, with no differential treatment outcomes being found. Ss' perceptions of therapist attributes and characteristics of therapy also failed to differ as a function of condition. Analyses ruled out such alternative explanations as therapist specificity or instrumentation deficiencies. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Value of wearing head protection gear while playing hurling

One of the three national games of Ireland, hurling is a contact team sport (15 a side) played with a metre long ash stick and a small hard leather ball. Over a 12 month period, 413 players were treated for hurling-related injuries at Cork Regional Hospital. While hand and facial trauma predominate, the proportion between the two sites has changed substantially from previous reports with a reduction in the level of facial injuries. The wearing of a helmet, and optionally a supplementary faceguard, is seen to have contributed to this trend. Despite this welcome reduction of facial injuries, a certain resistance to the use of protective headgear is evident, particularly among older players.     

Role of biotin-containing membranes and nuclear distribution in differentiating human endometrial cells

Human Ishikawa endometrial cells form domes when confluent monolayers are stimulated with fresh fetal bovine serum. Extensive structural and biochemical changes have been detected during the approximately 30 h differentiation period. The earliest detectable change involves the formation of multinucleated structures and the appearance of "granules" that stain for biotin within those structures. Nuclei become associated with each other and are ultimately enclosed within a biotin-containing membrane. Aggregated membrane-sheathed nuclei and the cells containing them begin to elevate from the dish as biotin staining becomes apparent in apical membranes. The elevated structures are called predomes and consist of one or more very large cells containing the sheathed nuclei. Apical membranes of these unusual cells extend far out into the medium in structures that resemble endometrial pinopods. A lumen under the elevated cells fills with transcytosed fluid. As differentiation proceeds, highly concentrated chromatin material that was flattened against apical and lateral membranes of the predome cells begins to disperse. Small mononuclear cells evolve from larger predome cells. Apical membranes of predome and dome cells continue to stain for biotin. Gel electrophoresis of SDS-solubilized biotin-containing membranes, followed by Western blot analysis using avidin-linked peroxidase, resulted in three stained bands with molecular weights similar to those of the mitochondrial carboxylases: propionyl carboxylase, methylmalonyl carboxylase, and pyruvate carboxylase.     

Nano‐Explosions of Nanoparticles for Sudden Release of Substances by Embedded Azo‐Components as Obtained via the Miniemulsion Process

The solid and thermally instable azoinitiators V‐65 and VR‐110 were embedded within a polymer particle by using the miniemulsion process and afterwards quickly decomposed by thermal treatment below the glass temperature of the polymer. The resulting nitrogen gas overpressure inside the particles leads to a disruption of the polymer particle and a possible sudden release of encapsulated substances. It is shown, by electron microscopic measurements, that the number of burst particles correlates with the applied temperatures as well as the heating time. The surface deformation could be verified by scanning electron microscope analyses.

     

Toward Low-Cost,High-Energy Density,and High-Power Density Lithium-Ion Batteries

Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by ~70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.     

Does the rose still smell as sweet? Item variability across test forms and revisions.

This article examines item stability when the same item appears in different contexts. The 1st section considers the assumptions in classical test theory and item response theory concerning the relationship between the item and the trait it is presumed to measure. The 2nd section presents contextualist challenges to the measurement theory assumptions about item properties and shows the instability of item characteristics across different testing contexts. The 3rd section describes methods for checking the relationship between items and traits. Classical test methods, item response methods, and structural equation methods for assessing item stability are reviewed. The instability of item characteristics across contexts should caution researchers to assess, and not assume, that items operate the same way on different test versions. Item instability also indicates the need for a more detailed understanding of the psychological processes that occur between item and answer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enterococcal diversity in the environment of an Irish Cheddar-type cheesemaking factory.

Enterococci are natural residents of human and animal intestinal tracts and grow to high levels in a variety of artisanal cheeses. The aim of this study was to determine the diversity of enterococci in a farmhouse raw-milk cheese production unit. Putative enterococci were isolated from the faeces of all the cows and all the people associated with the cheesemaking, from the milk and cheese during manufacture and ripening and from the environment in three separate trials. Almost 1400 isolates were screened using a genus-specific primer. The results indicated that all the human, milk, curd and cheese isolates but only 33.7%, 6.7% and 4.4% of the bovine isolates from the three trials, respectively, were members of the genus Enterococcus. RAPD-PCR was used to type the enterococcal isolates. In general, only E. faecium was found in the bovine faeces while E. casseliflavus dominated the human faeces, milk and cheese followed by lower numbers of E. faecalis. Environmental sampling of the water in the milking parlour and rinses of the cows' teats, the bulk-milk storage tank and the milking machine corroborated these results as E. casseliflavus and E. faecalis were the only Enterococcus species found in these samples. The putative vancomycin-resistant enterococci (VRE), isolated in Trial 1, were shown to be Pediococcus spp. by genotypic and phenotypic analysis.     

Asymptotic solvers for second-order differential equation systems with multiple frequencies

In this paper, an asymptotic expansion is constructed to solve second-order differential equation systems with highly oscillatory forcing terms involving multiple frequencies. An asymptotic expansion is derived in inverse of powers of the oscillatory parameter and its truncation results in a very effective method of dicretizing the differential equation system in question. Numerical experiments illustrate the effectiveness of the asymptotic method in contrast to the standard Runge–Kutta method.