New ribosome-inactivating proteins with polynucleotide:adenosine glycosidase and antiviral activities from Basella rubra L. and bougainvillea spectabilis Willd

New single-chain (type 1) ribosome-inactivating proteins (RIPs) were isolated from the seeds of Basella rubra L. (two proteins) and from the leaves of Bougainvillea spectabilis Willd. (one protein). These RIPs inhibit protein synthesis both in a cell-free system, with an IC50 (concentration causing 50% inhibition) in the 10(-10) M range, and by various cell lines, with IC50S in the 10(-8)-10(-6) M range. All three RIPs released adenine not only from rat liver ribosomes but also from Escherichia coli rRNA, polyadenylic acid, herring sperm DNA, and artichoke mottled crinkle virus (AMCV) genomic RNA, thus being polynucleotide:adenosine glycosidases. The proteins from Basella rubra had toxicity to mice similar to that of most type 1 RIPs (Barbieri et al., 1993, Biochim Biophys Acta 1154: 237-282) with an LD50 (concentration that is 50% lethal) < or = 8 mg.kg-1 body weight, whilst the RIP from Bougainvillea spectabilis had an LD50 > 32 mg.kg-1. The N-terminal sequence of the two RIPs from Basella rubra had 80-93% identity, whereas it differed from the sequence of the RIP from Bougainvillea spectabilis. When tested with antibodies against various RIPs, the RIPs from Basella gave some cross-reactivity with sera against dianthin 32, and weak cross-reactivity with momordin I and momorcochin-S, whilst the RIP from Bougainvillea did not cross-react with any antiserum tested. An RIP from Basella rubra and one from Bougainvillea spectabilis were tested for antiviral activity, and both inhibited infection of Nicotiana benthamiana by AMCV.     

Network implications of multicast in electronic commerce

Electronic commerce (EC) systems have been in existence for many years. In the financial industry, for example, electronic trading has been in place for well over a decade. Momentum has gathered pace to the point where EC is considered at least an essential adjunct to a company's business or, in some cases, the primary means of connecting vendors to their customers. This momentum has been at least, partly inspired by the convergence of content, commerce, communication, and the Internet. In many EC systems, the state of the market (current value and availability of goods and services) or another event needs to be disseminated to consumers so that they can take actions based on the information. IP multicasting is an emerging network technology that can greatly improve the efficiency of providing such information     

T-shaped shallow trench isolation with unfilled floating void

In this paper we propose a novel T-shaped shallow trench isolation technology including an unfilled floating void (VSTI). The structure aims to reduce the dark current in CMOS active pixel sensor technology and is optimized with respect to the size of the depletion region surrounding the STI, also accounting for the leakage current.Simulations outline that a large air void positioned far from the bottom and the top of the T-shaped trench improves performances.     

The use of panoramic viewing system in relaxing retinotomy and retinectomy

BACKGROUND: It can be argued that the ethical conduct of research involves achieving a balance between the rights and needs of three parties-potential research participants, society, and researchers. Local Research Ethics Committees (LRECs) have a number of roles and functions in the research enterprise, but there have been some indications that LREC members, researchers and the public can have different views about these responsibilities. Any such differences are potential sources of disagreement and misunderstanding. OBJECTIVES: To compare the views of LREC members, researchers and the public towards the roles and functions of LRECs. DESIGN: A questionnaire that contained items concerned with a variety of such roles was distributed to general practice patients (as proxies for potential research participants), researchers and LREC members. FINDINGS: While general practice patients believed that the main function of LRECs is to ensure that research participants come to no harm, LREC members were more concerned with the protection of participants' rights. There was also some disagreement between members and researchers with regard to the consideration of proposals on the grounds of scientific merit. CONCLUSIONS: Local Research Ethics Committee members need to be aware of potential differences in views, that they ought to make their priorities clear, and that membership of LRECs ought to reflect the views of both researchers and potential research participants.     

Hepatoxicity of ricin, saporin or a saporin immunotoxin: xanthine oxidase activity in rat liver and blood serum

Male Wistar rats each received an i.p injection of the ribosome-inactivating proteins ricin or saporin, or a Ber-H2 (anti-CD30)-saporin immunotoxin at a dose corresponding to three times the LD50 calculated for mice. Animals were killed 24, 48 or 72 h after treatment. Histological examination showed hepatic necrosis in all treated animals, although the sinusoidal lining was affected only in ricin-poisoned rats. The activities of xanthine dehydrogenase (D-form) and oxidase (O-form) were determined spectrophotometrically in liver and serum samples. In ricin-treated animals the liver enzyme was progressively converted from the D- to the O-form, which accounted for more than 60% of total activity after 48 h of poisoning, whilst no change in the xanthine oxidase activity was found in the serum. In the liver of rats treated with free or Ber-H2-conjugated saporin, the D-form was more than 75%, as in normal animals. In the same animals the serum xanthine oxidase activity was up to three-fold control values. The determination of serum xanthine oxidase may prove helpful in the evaluation of liver damage in patients treated with immunotoxins. It may become a diagnostic tool for the differential diagnosis of liver diseases.     

Vitreous changes and retinal detachment in highly myopic eyes

Although the impressive increase in the number of filters placed since 1988 is not surprising, it is appropriate to continue to review the indications for placement to determine whether abuse of these devices is occurring. Initially, there were very stringent requirements that were appropriate because there were few data to evaluate the efficacy and safety of the device. Now, data have been accumulated indicating the Greenfield filter has a high degree of efficacy (95%) and comparable caval patency (96%)32 for 20 years.1 Knowing that the filter is safe and effective, physicians are electing to place it in patients with greater comorbidity factors or with longer life-expectancy. In addition, advances in the treatment of patients with multiple trauma and malignancy have resulted in improved survival, leaving more patients at risk of DVT and PE. Finally, the number of patients older than age 60 is increasing rapidly, and the number of elective and emergent orthopaedic procedures is growing. All of these factors have led to an increased number of filter placements that should be considered appropriate. Although there are certainly cases in which the filter was placed without sufficient justification, the explosion in use can more accurately be correlated with changes in medical care, the established efficacy and safety of the device, the growing numbers of patients diagnosed with thromboembolism, and the increased awareness of the risk of complications from anticoagulation. When filter placement is preceded by a careful assessment of the patient to determine the risks and benefits of alternative treatments, there is little danger of abuse. However, more clinical investigation will be necessary to determine the optimal, cost-effective approach in situations in which controversy currently exists.     

Risk-neutral evaluation of information security investment on data centers

Based on given data center network topology and risk-neutral management, this work proposes a simple but efficient probability-based model to calculate the probability of insecurity of each protected resource and the optimal investment on each security protection device when a data center is under security breach. We present two algorithms that calculate the probability of threat and the optimal investment for data center security respectively. Based on the insecurity flow model (Moskowitz and Kang 1997) of analyzing security violations, we first model data center topology using two basic components, namely resources and filters, where resources represent the protected resources and filters represent the security protection devices. Four basic patterns are then identified as the building blocks for the first algorithm, called Accumulative Probability of Insecurity, to calculate the accumulative probability of realized threat (insecurity) on each resource. To calculate the optimal security investment, a risk-neutral based algorithm, called Optimal Security Investment, which maximizes the total expected net benefit is then proposed. Numerical simulations show that the proposed approach coincides with Gordon’s (Gordon and Loeb, ACM Transactions on Information and Systems Security 5(4):438–457, 2002) single-system analytical model. In addition, numerical results on two common data center topologies are analyzed and compared to demonstrate the effectiveness of the proposed approach. The technique proposed here can be used to facilitate the analysis and design of more secured data centers.     

Performance analysis of an RSVP-capable router

RSVP is a bandwidth reservation protocol that allows distributed real-time applications such as videoconferencing software to make bandwidth reservations over packet-switched networks. Coupled with real-time scheduling mechanisms built into packet routers, the network guarantees to provide the reserved bandwidth throughout the lifetime of the applications. Although guaranteed services are of great value to both end users and carrier providers, their performance cost, due to additional control and data processing overhead, can potentially have a negative impact on the packet throughput and latency of RSVP-capable routers. The goal of this article is to examine the performance cost of RSVP based on measurements from an industrial-strength RSVP implementation on a commercial IP router. The focus is on the detailed evaluation of the performance implications of various architectural decisions in RSVP. We found that RSVP's control messages do not incur significant overhead in terms of processing delay and bandwidth consumption. However, the performance overhead of real-time packet scheduling is noticeable in the presence of a large number of real-time connections. In extreme cases, the performance guarantees of existing real-time connections may not be kept, and some best-effort packets are actually dropped, although the overall bandwidth requirement from these connections is smaller than the available link bandwidth     

The effect of ribosome-inactivating proteins on the ribosome from the hyperthermophilic archaeon Sulfolobus solfataricus

Ten cadaver digits were used to evaluate excursion resistance between a tendon and pulley after completing 4 methods of pulley reconstruction (Bunnell's, Kleinert's, Lister's, and Karev's techniques). Five tissues (palmaris longus tendon, extensor digitorum tendon, flexor digitorum superficialis tendon, extensor retinaculum, and volar plate) were used to reconstruct the A2 pulley. Intrasynovial tissue sources (extensor retinaculum, volar plate, and flexor digitorum superficialis tendon) produced less excursion resistance than extrasynovial tissue sources (extensor digitorum tendon and palmaris longus tendon). The models using the extensor retinaculum and volar plate as reconstructive materials produced less excursion resistance than the normal A2 pulley, whereas the models using the palmaris longus tendon produced the highest excursion resistance. Bunnell's technique of pulley reconstruction produced less excursion resistance than Kleinert's technique with all 3 tissues tested. The results of the in vitro study of excursion resistance between the tendon and reconstructed pulley demonstrated that Lister's technique of pulley reconstruction using the extensor retinaculum produced the least resistance to tendon gliding.     

A Hybrid Spanning Tree algorithm for efficient topology distribution in PNNI

The ATM Forum's PNNI standard specifies a flooding mechanism to distribute topological state information amongst nodes participating in a PNNI network. While the flooding mechanism provides robust topology distribution, we show by simulation that it can disproportionately overload lower-bandwidth links and, due to its inherent redundancy, can generate considerable computational overhead due to the processing of redundant topology updates. To address these issues, we introduce the Hybrid Spanning Tree algorithm, a spanning tree-based topology distribution mechanism that has low computational maintenance and can support policy that restricts topology distribution control traffic from being carried over lower-bandwidth links. Unlike other spanning tree proposals, the Hybrid Spanning Tree algorithm provides a simple and practical migration path to smoothly transition PNNI nodes executing the flooding algorithm to those of the Hybrid Spanning Tree algorithm. This revised version was published online in August 2006 with corrections to the Cover Date.