Removal of trace quantities of nickel from solution

Chitosan, which is produced from the natural polymer chitin, is a much more efficient scavenger of nickel ion than other natural ion exchange materials tested. An industrial waste containing about 7 ppm Ni²⁺ and 10,000 ppm Na⁺ was reduced to less than 0.1 ppm Ni²⁺ by contact in a packed column of chitosan. Capacity of the chitosan substrate under these conditions was a little more than 1 meq/g. The substrate can be regenerated by contact with buffered NH₄Cl at pH 10. The high sodium content of the nickel waste did not prevent sorption of Ni²⁺, but it apparently produced an interference with atomic absorption spectrophotometer analyses, giving a spurious reading of 0.8 ppm Ni²⁺ when the major nickel line at 232 nm was used for analysis.     

Incorporation of dietarycis andtrans octadecenoate isomers in the lipid classes of various rat tissues

The percentage distribution of the geometrical and positional isomers in the hexadecenoates and octadecenoates isolated from triglycerides, phosphatidylcholines, and phosphatidylethanolamines of brain, heart, kidney, liver, lung, muscle, spleen, and adipose tissues from rats maintained four weeks on a semipurified diet supplemented with 15% partially hydrogenated safflower fatty acids, has been determined. Except for brain, octadecenoate percentages were increased in each of the lipid classes of all the tissues by the dietary fat. Although the diet did not contain detectable hexadecenoates, the 16∶1 fraction from the lipid classes of all the tissues was composed of 10–70% of thetrans isomers, indicating chain shortening of the dietary octadecenotes. Distribution ofcis andtrans positional isomers in triglyceride hexadecenoates was approximately the same in all tissues. Relatively high percentages of the Δ9, Δ10, and Δ11 isomers were observed, but the Δ8 was the predominatingtrans hexadecenoate isomer, indicating preferential chain shortening of thetrans δ10 octadecenoate.Trans octadecenoates were found in all tissues, but concentrations were dependent on tissue and lipid class. The distribution of thecis andtrans octadecenoate isomers was similar in all the tissue triglycerides, with the distribution of thetrans isomers resembling the diet. In contrast, the percentage distribution of thetrans octadecenoates in the phospholipid classes differed dramatically from the diet, and the distribution was dependent on both the tissue and lipid class. The Δ12, Δ13, and Δ14trans octadiet, suggesting an accumulation of these isomers. Although thecis Δ10 octadecenoate was a significant dietary component, this isomer was not incorporated significantly into any lipid class of any tissue. The metabolic fate of this isomer remains unknown.     

An energy-efficient reconfigurable analog-to-digital converter for orthopedic implants

This paper presents a pipelined analog to digital converter (ADC) with reconfigurable resolution and sampling rate for biomedical applications. Significant power saving is achieved by turning off the sample-and-hold stage and the first two pipeline stages of the ADC instead of turning off the last two stages. The reconfiguration scheme allows having three modes of operation with variable resolutions and sampling rates. Reconfigurable operational transconductance amplifiers and an interference elimination technique have been employed to optimize power-speed-accuracy performance in biomedical instrumentation. The proposed ADC exhibits a 56.9 dB SNDR with 35.4 mW power consumption in 10-bit, 40 MS/s mode and 49.2 dB SNDR with only 7.9 mW power consumption in 8-bit, 2.5 MS/s mode. The area of the core layout is 1.9 mm² in a 0.35 μm bulk-CMOS process.     

On Chip Signal Generators for Low Overhead ADC BIST

Testing of ADCs deeply embedded in SOCs is a significant challenge due to access limitations. ADC Built-in self-test (BIST) is considered a promising alternative to traditional test. This paper investigates implementation issues in adapting the stimulus error identification and removal (SEIR) algorithm, originally developed for production test, into a practical ADC BIST solution. Signal generators with very low transistor count and area consumption are presented. Extremely simple methods for generating small constant voltage level shifts are introduced and evaluated. Simulation results show that the generated signals, together with the level shifts, are able to test a 16-bit ADC to 16 bit accuracy levels. These results demonstrate that accurate BIST of deeply embedded analog and mixed-signal (AMS) blocks may be practically implemented on chip with very low overhead.     

Rate-distortion optimized hybrid error control for real-time packetized video transmission.

The problem of application-layer error control for real-time video transmission over packet lossy networks is commonly addressed via joint source-channel coding (JSCC), where source coding and forward error correction (FEC) are jointly designed to compensate for packet losses. In this paper, we consider hybrid application-layer error correction consisting of FEC and retransmissions. The study is carried out in an integrated joint source-channel coding (IJSCC) framework, where error resilient source coding, channel coding, and error concealment are jointly considered in order to achieve the best video delivery quality. We first show the advantage of the proposed IJSCC framework as compared to a sequential JSCC approach, where error resilient source coding and channel coding are not fully integrated. In the USCC framework, we also study the performance of different error control scenarios, such as pure FEC, pure retransmission, and their combination. Pure FEC and application layer retransmissions are shown to each achieve optimal results depending on the packet loss rates and the round-trip time. A hybrid of FEC and retransmissions is shown to outperform each component individually due to its greater flexibility.     

WritingResearchWriting: The Semantic Web and the Future of the Research Project

In this essay, I explore one advancement in particular—the Semantic Web—and discuss ways in which it stands to change students’ interaction with information in digital spaces, and how new forms of interaction could impact the teaching of writing. I go back to the earliest days of the Web in order to remind readers how information retrieval has evolved in the digital age. I also provide a general discussion of the vision, current state, and possible futures of the Semantic Web, and I focus on how the Semantic Web might alter the research process and, more importantly, the research-writing relationship. I also offer suggestions for teaching composition in advance of and for the Semantic Web. Although the Semantic Web is still several years off, I contend that research and writing will merge into a single process, thus presenting new opportunities for the teaching of writing then and, perhaps more importantly, now. These opportunities include helping students to identify the challenges of information retrieval and overload, to see research as more about establishing links and connections between information sources and less about finding the “right” sources, and to write for the Semantic Web—and, in doing so, teach students that researching and writing are inseparable.     

Loneliness,anxiousness, and substance use as predictors of Facebook use

This study investigates the relationships between loneliness, anxiousness, alcohol, and marijuana use in the prediction of freshman college students’ connections with others on the social network site Facebook as well as their emotional connectedness to Facebook. A survey of 229 respondents was conducted at a mid-sized public university to examine these relationships. Respondents were currently living in university dormitories and had an active Facebook account. The study examined the aforementioned predictor variables in relation to Facebook connections strategies and emotional connectedness to Facebook. Results showed that anxiousness, alcohol use, and marijuana use predicted emotional attachment to Facebook. Additionally, loneliness and anxiousness, but not alcohol or marijuana use, predicted individuals’ connections with others using Facebook. The current study adds to the growing body of literature investigating predictors of why individuals become emotionally attached to Facebook and the precursors to connecting with others on Facebook.