The kinetics of hammer milling of maize

The kinetics of breakage of maize were measured in a small laboratory hammer mill, with a rigid blade used as hammer. It was found that breakage was first-order, and that the primary breakage distributions were insensitive to mill conditions or moisture content of the material. The specific rates of breakage were dependent on particle size to approximately the third power; they increased as moisture content of the grain was reduced, showing that the drier material was more brittle; and a minimum rotation speed was necessary to get significant breakage. It appeared that material was thrown to the outer wall, so that only the ends of the hammer were effective, and a major part of fracture occurred by particles being thrown against the wall; an optimum loading exists for maximum breakage rates.     

Rethinking information theory for mobile ad hoc networks

The subject of this article is the long standing open problem of developing a general capacity theory for wireless networks, particularly a theory capable of describing the fundamental performance limits of mobile ad hoc networks. A MANET is a peer-to-peer network with no preexisting infrastructure. MANETs are the most general wireless networks, with single-hop, relay, interference, mesh, and star networks comprising special cases. The lack of a MANET capacity theory has stunted the development and commercialization of many types of wireless networks, including emergency, military, sensor, and community mesh networks. Information theory, which has been vital for links and centralized networks, has not been successfully applied to decentralized wireless networks. Even if this was accomplished, for such a theory to truly characterize the limits of deployed MANETs it must overcome three key roadblocks. First, most current capacity results rely on the allowance of unbounded delay and reliability. Second, spatial and timescale decompositions have not yet been developed for optimally modeling the spatial and temporal dynamics of wireless networks. Third, a useful network capacity theory must integrate rather than ignore the important role of overhead messaging and feedback. This article describes some of the shifts in thinking that may be needed to overcome these roadblocks and develop a more general theory.     

On the duality of Gaussian multiple-access and broadcast channels

We define a duality between Gaussian multiple-access channels (MACs) and Gaussian broadcast channels (BCs). The dual channels we consider have the same channel gains and the same noise power at all receivers. We show that the capacity region of the BC (both constant and fading) can be written in terms of the capacity region of the dual MAC, and vice versa. We can use this result to find the capacity region of the MAC if the capacity region of only the BC is known, and vice versa. For fading channels we show duality under ergodic capacity, but duality also holds for different capacity definitions for fading channels such as outage capacity and minimum-rate capacity. Using duality, many results known for only one of the two channels can be extended to the dual channel as well.     

Induction of heat shock protein 60 expression in human monocytic cell lines infected with Mycobacterium leprae

Monocytic cell lines (HL-60 and THP-1) were infected with viable Mycobacterium leprae. Levels of human hsp60 were estimated by Western blot (immunoblot) assay and a sandwich enzyme-linked immunosorbent assay. The results showed that infection of both of the cell lines induced the synthesis of human hsp60, which may be of significance in relation to autoimmune manifestations associated with mycobacterial infections.     

Stability Indicating Hplc Method for Ribavirin and its Pharmaceutical Dosage Forms

The present work describes a specific, stability indicating HPLC method for determination of Ribavirin (1) and its pharmaceutical dosage forms.

Ribavirin was chromatographed on a microbondapak C18 column utilizing a simple mixture of 0.01M dibasic potassium phosphate and methanol (95: 5). The detection was done at 207 nm.

The available literature was scanned to locate the various methods(2,3) available along with the one reported in USP XXII.

A comparative study was made of the proposed method and USP method and the advantages over the USP method have been discussed.

The low value of Relative standard deviation and recovery of the drug in the range of 99.1% to 101.5% indicates a good precision and non-interference of the method.     

Intraoperative placement of a Wallstent for portal vein stenosis and thrombosis after liver transplantation

We report a case of orthotopic liver transplantation, in which portal vein thrombosis developed in the immediate postoperative period. Surgical thrombectomy and intraoperative placement of a large caliber Wallstent resulted in long-term patency. The unique feature of this case is the intraoperative placement of the stent via the inferior mesenteric vein under fluoroscopic guidance. The use of a large caliber (16 mm) stent obviated the need for postoperative anticoagulation.     

CMOS device noise considerations for terabit lightwave systems

An improved model to predict sensitivity of p-i-n lightwave receivers using CMOS technology is proposed. This model incorporates the latest understanding of excess channel noise observed in nanoscale MOSFETs. For the case of an ideal channel filter, the results are presented in an analytical closed form. For nonideal channels, the concept of higher order Personick integrals is introduced. Up to 10 Gb/s, the results predicted by the above model closely mimic the existing CMOS data published over the last 20 years. Above 10 Gb/s, due to lack of CMOS data, projections are evaluated against the nonsilicon technologies. The predictions compare very favorably with the measured system performance using high electron mobility transistors and heterojunction bipolar transistors. The findings thus indicate that CMOS should claim its status as the low-cost high-performance highly integrated technology of choice for lightwave applications beyond 10 Gb/s.     

Electric field dependence of mobility fluctuation 1/f; noise in elemental semiconductors

It is shown that Bosman's empirical formula α(E) = α(0)/[1 + (E/E_c′)²] for the field dependence of Hooge's parameter can be explained if it is assumed that only the low-field value μ_aco of the acoustical mobility μ_ac fluctuates and that $\text{μ}{}_{\mathrm{ac}}\text{= μ}{}_{\mathrm{aco}}\text{[1 + (E/E}{}_{\mathrm{c}}\text{′)}{}^2\text{]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$.     

Prostate-specific antigen values and their clinical significance in renal transplant recipients

BACKGROUND: In the diagnosis of prostate cancer, prostate-specific antigen (PSA) is the most clinically useful tumor marker. Its utility in renal transplant patients is unclear. We hypothesized that PSA values might be affected by the renal function, immunosuppression, or proteinuria. METHODS: Three hundred four PSA values were measured in 166 patients >40 years (53.5 +/- 7.2 years, mean +/- SD, range 44.4 to 76.2). Charts were reviewed for 24-hour creatinine clearance, 24-hour urinary protein, cyclosporine use, age at the time of each PSA test, and evaluation done in response to the PSA result. Analyses used the Mann-Whitney U test and simple regression model. RESULTS: Twenty-five values in 13 patients were >4.0 ng/mL. Of these, 6 patients (6 values) had normal repeat PSA values; 3 patients (11 values) had negative evaluations for prostate cancer; and 4 patients (8 values) were diagnosed with prostate cancer. The latter 4 patients were excluded from the denoted normal group leaving 294 PSA values in 162 patients. The mean normal PSA was 1.3 +/- 1.8 ng/mL, range 0.1 to 20.2. The pretreatment mean PSA for recipients with prostate cancer was 302 +/- 800, range 8.0 to 2,281. An elevated PSA value was associated with a 31% incidence of prostate cancer. There was no association of PSA levels with cyclosporine use, 24-hour creatinine clearance, or 24-hour urinary protein, but there was with age. CONCLUSIONS: Prostate-specific antigen values in renal transplant recipients are similar to those in the general population and are not influenced by cyclosporine or by renal function. We recommend routine measurement of PSA in male transplant recipients.