Harnessing the Melting Peculiarities of Ultra‐High Molecular Weight Polyethylene Fibers for the Processing of Compacted Fiber Composites

Summary: Compacted fiber composites offer unique properties due to their lack of an extraneous matrix. The conditions of processing ultra‐high molecular weight polyethylene (UHMWPE) fibers were simulated in a heated pressure cell. In situ X‐ray diffraction measurements were used to follow the relevant transitions and the changes in the degree of crystallinity during melting and crystallization. The results strongly support the suggestion that the hexagonal crystal phase, in which the chain conformation is extremely mobile on the segmental level, constitutes the physical basis of compaction technologies for processing UHMWPE fibers into a single‐polymer composite. This report suggests that using a pseudo‐phase diagram outlining the occurrence of different phases during slow heating and the degree of crystallinity can provide valuable insight into the technological parameters relevant for optimal processing conditions.

Degree of crystallinity as a function of pressure and temperature in a region relevant to compaction processes.     

Distilled Collections from Textual Image Queries

We present a distillation algorithm which operates on a large, unstructured, and noisy collection of internet images returned from an online object query. We introduce the notion of a distilled set, which is a clean, coherent, and structured subset of inlier images. In addition, the object of interest is properly segmented out throughout the distilled set. Our approach is unsupervised, built on a novel clustering scheme, and solves the distillation and object segmentation problems simultaneously. In essence, instead of distilling the collection of images, we distill a collection of loosely cutout foreground “shapes”, which may or may not contain the queried object. Our key observation, which motivated our clustering scheme, is that outlier shapes are expected to be random in nature, whereas, inlier shapes, which do tightly enclose the object of interest, tend to be well supported by similar shapes captured in similar views. We analyze the commonalities among candidate foreground segments, without aiming to analyze their semantics, but simply by clustering similar shapes and considering only the most significant clusters representing non‐trivial shapes. We show that when tuned conservatively, our distillation algorithm is able to extract a near perfect subset of true inliers. Furthermore, we show that our technique scales well in the sense that the precision rate remains high, as the collection grows. We demonstrate the utility of our distillation results with a number of interesting graphics applications.     

A continuous/discrete simulation of controlled atmosphere (CA) cool storage systems: evaluation of plant performance/design and product quality evolution

In this paper, a controlled atmosphere storage model, developed earlier, is validated using an industrial CA cool storage facility with stepwise product loading strategy. The proposed combined continuous and discrete CA cool storage simulation model was able to represent the step response transients and continuous events, with accuracy less than the observed variability or at best with accuracy level as set by the measurement instrument. Moreover, the handling of discrete/continuous events enabled the implementation of practical operational procedures and to investigate their implication on plant performance/design and directly on the product quality. The model is a valid working model for design and optimization of CA cool storage facilities both with respect to plant performance and final quality of the stored product.     

Efficient Incorporation of Clickable Unnatural Amino Acids Enables Rapid and Biocompatible Labeling of Proteins in Vitro and in Bacteria

Site-specific incorporation of unnatural amino acids (uAAs) bearing a bioorthogonal group has enabled the attachment – typically at a single site or at a few sites per protein – of chemical groups at precise locations for protein and biomaterial labeling, conjugation, and functionalization. Herein, we report the evolution of chromosomal Methanocaldococcus jannaschii tyrosyl-tRNA synthetase (aaRS) for the alkyne-bearing uAA, 4-propargyloxy-l -phenylalanine (pPR), with ∼30-fold increased production of green fluorescent protein containing three instances of pPR compared with a previously described M. jannaschii-derived aaRS for pPR, when expressed from a single chromosomal copy. We show that when expressed from multicopy plasmids, the evolved aaRSs enable the production – using a genomically recoded Escherichia coli and the non-recoded BL21 E. coli strain – of elastin-like polypeptides (ELPs) containing multiple pPR residues in high yields. We further show that the multisite incorporation of pPR in ELPs facilitates the rapid, robust, and nontoxic fluorescent labeling of these proteins in bacteria. The evolved variants described in this work can be used to produce a variety of protein and biomaterial conjugates and to create efficient minimal tags for protein labeling.     

Structure of the Equilibrated Ni(111)‐YSZ(111) Solid–Solid Interface

Solid‐state dewetting of continuous Ni films deposited on the (111) surface of yttrium‐stabilized zirconia (YSZ) was used to produce equilibrated Ni particles, and the solid–solid interface structure was determined using aberration‐corrected transmission electron microscopy. The ~150 nm thick Ni films were annealed at 1350°C in Ar + H₂ (99.9999%) at a partial pressure of oxygen of 10^?20 atm for 6 h. Transmission electron microscopy of equilibrated particles, which was conducted to analyze the structure at the interface, revealed that despite the 31% lattice mismatch between Ni and YSZ, the interface is semicoherent and a two‐dimensional network of misfit dislocations was identified.     

Crankback Prediction in Hierarchical ATM Networks

When an ATM node discovers that it cannot continue the setup of a virtual channel under the requested Quality of Service (QoS), it initiates a backtracking procedure called crankback. We propose a novel scheme, referred to as crankback prediction, that decreases the crankback overhead. Under the proposed scheme, nodes check during the connection admission control procedure whether the establishment of a virtual channel has a good chance to be admitted over the entire designated route. If this is not the case, crankback is initiated even before a particular QoS parameter is violated. The main idea behind the proposed scheme is to allocate a quota to the Peer Groups (PGs) along the message path, and then to suballocate this quota to the child PGs of these PGs. This process continues recursively until reaching the 1-level PG, which contains only physical nodes. The main advantage of the proposed scheme is that it lowers the setup delay and the processing and communication load imposed by signaling messages that establish unused portions of Virtual Channels (VCs)     

Continuous/discrete simulation of controlled atmosphere (CA) cool storage systems: model development and validation using pilot plant CA cool storage

Simulation of dynamic processes in controlled atmosphere (CA) cool room storage systems has been developed. The model consists of three interacting sub-models for the prediction of the transient behavior of the processes in the three units, namely, the cool room, the refrigeration system and the gas-handling unit. Several modules representing each of the components in these units were developed based on energy and mass balances. The modules were then arranged to form the sub-models, which were interconnected, in turn, into the global CA cool storage system model. The modules were implemented in an object-oriented computational environment, (EcosimPro) which can handle both continuous and discrete events. The model was validated using experimental data from a pilot plant CA cool storage facility. Model predictions of the most important discrete and continuous processes were found to agree to the experimental data with a maximum difference less than the observed spatial variability or at best with the accuracy level as set by the measurement instruments. As product respiration and quality models are incorporated, it is possible to use the model for optimization of plant performance with respect to the final quality of the stored product. Moreover, the handling of discrete/continuous events enables the implementation of practical operational procedures and to investigate their implication directly on the product quality and plant performance/design.     

A three-person perspective on transference.

Different approaches to psychoanalysis may be classed according to the number of persons that they assume to be necessary in order to adequately describe mental life. One-person approaches assume the basic autonomy of the individual to act as a subject in her world, while 2-person approaches assume the irreducibility of object and subject, their essential complementarity and their mutual affirmation as subjects. Three-person approaches, on which the present article focuses, argue that the subject can fully develop only by creating enough space for herself among other persons who compete for subject positions. Such space is created in relation to (at least) 2 other subjects, hence the system of 3 persons. In the 3-person perspective, the position of the subject is defined as First, and the Second is defined by the one with whom the subject identifies and in whom she mirrors herself through cycles of projection and introjection. The position of the Third involves the personification of the cultural matrix and, especially, the way language informs our ability to relate to each other. This is best represented in the universal system of personal pronouns: the subject takes the position of the 1st person (I), the Second takes the position of the 2nd person (You), and the Third is posited as the 3rd person (she or he and it). In psychoanalytic therapy, the patient takes the position of the Subject, the First. Transference is construed as the superposition of both the 2nd and the 3rd persons upon the figure of the analyst, a mental process that (re)creates the necessary conditions for the development of subjecthood. As a result, in the discourse of transference, the position of the analyst keeps fluctuating between the 2nd and 3rd positions: When one takes place on the actual level, the other acts in the background, and vice versa. The therapeutic consequences of this view are discussed; for example, transference love is construed as a process in which the 2nd person struggles to dominate the positioning of the analyst. Other transferential configurations are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human umbilical cord blood stem cells: rational for use as a neuroprotectant in ischemic brain disease

The use of stem cells for reparative medicine was first proposed more than three decades ago. Hematopoietic stem cells from bone marrow, peripheral blood and human umbilical cord blood (CB) have gained major use for treatment of hematological indications. CB, however, is also a source of cells capable of differentiating into various non-hematopoietic cell types, including neural cells. Several animal model reports have shown that CB cells may be used for treatment of neurological injuries. This review summarizes the information available on the origin of CB-derived neuronal cells and the mechanisms proposed to explain their action. The potential use of stem/progenitor cells for treatment of ischemic brain injuries is discussed. Issues that remain to be resolved at the present stage of preclinical trials are addressed.     

Hydrothermal degradation of adsorbed sulfur mustard on activated carbon

Thermal and hydrothermal degradations of adsorbed sulfur mustard (HD) on activated carbon particles from a chemical protective over-garment were studied. Carbon loaded with 5 wt.% HD was heated in a closed reactor at temperatures up to 160 °C for 0.5–6 h and analyzed by solid-state ¹³C MAS NMR. On dry carbon at room temperature, HD was stable for months. On a thoroughly pre-wetted carbon, adsorbed HD partially degraded to thiodiglycol (TDG) and TDG-sulfoxide (TDG-SO) within 2–3 months. Heating dry HD-loaded carbon to 160 °C caused partial degradation within 4 h to 1,4-thioxane, along with 1,4-dithiane and vinyl sulfides. Complete degradation within 2.5 h to the same products occurred upon hydrothermal treatment of the HD-loaded carbon, using a water/carbon ratio of 0.3:1. With higher water/carbon ratios of 0.6:1–5:1 at temperatures of 120 °C and above, adsorbed HD hydrolyzed rapidly within 0.5 h. The latter reaction led to the formation of TDG concurrent with either thioxane (at 160 °C) or TDG-SO and TDG-dimer (at 120 °C). The mechanisms of the observed degradation processes are discussed.