Free-radical grafting of cellulose in N-methylmorpholine oxide: Water-soluble pam-g-cellulose copolymers

The homogeneous graft copolymerization of acrylamide (AM) onto cellulose initiated by t-butylperoxy-2-ethylhexanoate in a cellulose solvent, N-methylmorpholine oxide (NMMO), was investigated. The method afforded water-soluble PAM-g-cellulose copolymers in fair yields. The copolymers produced are of low molecular weight (50,000–100,000 M?_w). Little apparent homopolymerization was observed.     

Effects of soaking soybeans in dilute acids on biologically active components

Soaking soybeans in dilute acids affected activities of lipoxygenase, trypsin inhibitor and urease. Effects of soaking time, acid concentration and soaking temperature were investigated. Lipoxygenase activity was completely eliminated by soaking in 0.3 M HC1 at either 23°C or 40°C for 8 hr. Less than 50% trypsin inhibitor remained and urease was inactivated to an acceptable level (0.04 ΔpH).     

Effect of simulated freeze damage on soybean seed composition and functionality

Two soybean varieties (Beeson and Williams) were harvested at various maturation levels by applying paraquat directly to the growing plant. The application of this herbicide to arrest growth was used to simulate freeze damage. The free fatty content and the photometric index declined from 0.61% to 0.19% and 301.56 to 201.90, respectively, as maturation progressed for the Beeson variety. Similar trends were found with the Williams variety. However, the amount of trypsin inhibitor differed between the two varieties depending upon maturation level.     

Studies on the lipids of sheep red blood cells. II. The incorporation of phosphorus into phospholipids of HK and LK cells

The incorporation of inorganic phosphate (as NaH₂PO₄) into the phospholipids of sheep red blood cells was studied in vitro in blood samples from five highpotassium (HK) and five low-potassium (LK) sheep. The erythrocytes from HK sheep incorporated more activity in 4 hr than those from the LK sheep. However no activity was incorporated into the major phospholipids of the cells (phosphatidyl ethanolamine, phosphatidyl serine, and sphingomyelin) of either group. The phosphatidic acid fraction was labeled in both groups and to a significantly greater extent in the HK samples. However the highest activity in the phospholipid of sheep red-cells was located in three unknown compounds not previously detected. Their specific activities were the same in the HK and the LK samples although they were present in slightly larger amounts in the HK samples. In general, incorporation was at a rather low level, and from stoichiometric considerations it was concluded that the metabolism in the red-cell phospholipids could not be directly involved in the active transport of ions across the cell membrane. This work also confirmed a previous report that no quantitative differences exist among the major phospholipid classes in the two types of cells.     

Who and what links to the Internet Archive

The Internet Archive’s (IA) Wayback Machine is the largest and oldest public Web archive and has become a significant repository of our recent history and cultural heritage. Despite its importance, there has been little research about how it is discovered and used. Based on Web access logs, we analyze what users are looking for, why they come to IA, where they come from, and how pages link to IA. We find that users request English pages the most, followed by the European languages. Most human users come to Web archives because they do not find the requested pages on the live Web. About 65 % of the requested archived pages no longer exist on the live Web. We find that more than 82 % of human sessions connect to the Wayback Machine via referrals from other Web sites, while only 15 % of robots have referrers. Most of the links (86 %) from Websites are to individual archived pages at specific points in time, and of those 83 % no longer exist on the live Web. Finally, we find that users who come from search engines browse more pages than users who come from external Web sites.     

Pharmacodynamics of some individual milkweed cardenolides fed to larvae of the monarch butterfly (Danaus plexippus L.)

Adult monarch butterflies,Danaus plexippus L. (Lepidoptera: Danaidae), store only some of the cardenolides present in the larval milkweed (Asclepiadaceae) host. Feeding known doses of individual cardenolides to 4th instar monarch larvae led to more efficient larval tissue incorporation at low doses than at high ones, and favored storage of cardenolide glycosides over genins. A qualitative regulation also occurs during larval feeding; calactin and calotropin were stored as such but uscharidin was rapidly converted to a mixture of calactin and calotropin which were the forms stored by the larvae. Two genins, uzarigenin and digitoxigenin, were stored by larvae as polar cardenolide metabolites.Research supported by National Science Foundation grants DEB 7514266 and DEB 7514266-AO2 (U.C. Davis) and DEB 7514265 (Amherst College).     

Automation in the pharmaceutical analysis laboratory: a centralized/decentralized approach

It has been over 10 years since robots have appeared in the pharmaceutical analysis laboratory. In the early days, it was common for one selected individual to be responsible for the programming, usage and maintenance of the robots(s). However, the increasing use of robotics has prompted the formation of robotics ‘laboratories’ and/or ‘groups’. This is especially true when multiple robotic systems and applications are involved.Over the past several years at ISLAR, many champions of robotics have given presentations on the setup and usage of robotics within their organizations. These managers have described both the ‘centralized’ and ‘decentralized’ approaches to the implementation of robotics. In the centralized system, a single group is charged with all aspects of the robotic project, including justification, purchase, validation, use and maintenance. Under such an arrangement, samples are usually given to the robotics group for analysis. In contrast, a totally decentralized approach to robotics would have units interspersed throughout the organization, with each individual group responsible for their respective unit(s), in much the same way as liquid chromatographs are considered.At Hoffmann-La Roche, aspects of both the centralized and decentralized approaches to robotics are used which make our combined system the ‘best of both worlds’. This paper describes the Roche philosophy towards robotics and highlights the advantages to the system used.     

TBC experience in land- based gas turbines

This paper summarizes prior and on-going machine evaluations of thermal barrier coatings (TBC) for power generation, that is large industrial gas turbine applications. Rainbow testing of TBCs on turbine nozzles, shrouds, and buckets are described along with a test of combustor liners. General Electric Power Generation has conducted more than IS machine tests on TBC turbine nozzles with various coatings. TBC performance has been quite good, and additional testing, including TBCs on shrouds and buckets, is continuing. Included is a brief comparison of TBC requirements for power generation and aircraft turbines.     

Understanding student participation in undergraduate course communities: A case study

Participation is the cornerstone of any community. Promoting, understanding and properly managing it allows not only keeping the community sustainable, but also providing personalized services to its members and managers. This article presents a case study in which student participation in a course community was motivated using two different extrinsic mechanisms, and mediated by a software platform. The results were compared with a baseline community of the same course, in which participation was not motivated by external means. The analysis of these results indicates that managing a partially virtual course community requires the introduction of monitoring services, community managers and extrinsic mechanisms to motivate participation. These findings allow community managers to improve their capability for promoting participation and keeping the community sustainable. The findings also raise several implications that should be considered in the design of software supporting this kind of community, when managing the participation of its members.     

On the complexity of bandwidth allocation in radio networks

We define and study an optimization problem that is motivated by bandwidth allocation in radio networks. Because radio transmissions are subject to interference constraints in radio networks, physical space is a common resource that the nodes have to share in such a way, that concurrent transmissions do not interfere. The bandwidth allocation problem we study under these constraints is the following. Given bandwidth (traffic) demands between the nodes of the network, the objective is to schedule the radio transmissions in such a way that the traffic demands are satisfied. The problem is similar to a multicommodity flow problem, where the capacity constraints are replaced by the more complex notion of non-interfering transmissions. We provide a formal specification of the problem that we call round weighting  . By modeling non-interfering radio transmissions as independent sets, we relate the complexity of round weighting to the complexity of various independent set problems (e.g. maximum weight independent set, vertex coloring, fractional coloring). From this relation, we deduce that in general, round weighting is hard to approximate within n^1−ε$n^{1-\epsilon }$ (n$n$ being the size of the radio network). We also provide polynomial (exact or approximation) algorithms e.g. in the following two cases: (a) when the interference constraints are specific (for instance for a network whose vertices belong to the Euclidean space), or (b) when the traffic demands are directed towards a unique node in the network (also called gathering, analogous to single commodity flow).