SLA brokering and bandwidth reservation negotiation schemes for QoS-aware internet

We present a novel Service Level Agreement (SLA)-driven service provisioning architecture, which enables dynamic and flexible bandwidth reservation schemes on a per-user or per-application basis. Various session level SLA negotiation schemes involving bandwidth allocation, service start time and service duration parameters are introduced and analyzed. The results show that these negotiation schemes can be utilized for the benefit of both end users and network providers in achieving the highest individual SLA optimization in terms of key Quality of Service (QoS) metrics and price. The inherent characteristics of software agents such as autonomy, adaptability and social abilities offer many advantages in this dynamic, complex, and distributed network environment especially when performing Service Level Agreements (SLA) definition negotiations and brokering tasks. This article also presents a service broker prototype based on Fujitsu's Phoenix Open Agent Mediator (OAM) agent technology, which was used to demonstrate a range of SLA brokering scenarios.     

Efficient transfer and concentration of energy between explosive dual bubbles via time-delayed interactions

The dynamics of a high heat flux thermal bubble is constrained by the thermal energy carried on the bubble surface right after the bubble formation because of thermal isolation of vapor. This article proposes a way by assigning time delays between dual bubbles to transfer effectively energy from one bubble into the other, thus, breaks energy limitation that one single bubble can usually carry. Experiment result has demonstrated that the useful work as large as 40% can be transferred from one bubble into the other for the ignition time delay set between 2 and 3 μs in a dual bubble system. At the same time, the total extractable useful work in a dual bubble system is 20% higher than twice that of a single-bubble system with the same input heat energy. This phenomenon opens up a new way to transfer or concentrate energies from distributed energy sources with limit energy density into a much higher one for higher power application.     

Endwall heat transfer and pressure drop in scale-roughened pin-fin channels

There is a growing requirement for improved heat transfer performance for a number of electronic devices and this dictates a need to further elevate the endwall heat transfer performances for pin-fin channels. Driven by this need, a novel compound heat transfer enhancement (HTE) measure that combines deepened scales and pin-fin array is devised. Characteristics of heat transfer and pressure drop performances in two scale-roughened pin-fin channels with two different pin pitch-to-diameter ratios are compared for both forward and backward flows in the Reynolds Number (Re) range of 1000–30000. Comparisons of heat transfer data, pressure drop measurements and thermal performance factors with previous results collected from a variety of single and compound HTE devices demonstrate the significant augmentations in both heat transfer rates and pressure drop coefficients for the present HTE measure. This present compound HTE measure with scales and pin-fin array demonstrates an enhancement on the heat transfer up to of 22 times of the developed flow references in smooth-walled pipe within the Re range of 1000–30000. Experimental correlations of heat transfer and pressure-drop coefficients for two scale-roughened pin-fin channels with forward and backward flows are derived to assist design applications.     

Potent‐By‐Design: Amino Acids Mimicking Porous Nanotherapeutics with Intrinsic Anticancer Targeting Properties

Exogenous sources of amino acids are essential nutrients to fuel cancer growth. Here, the increased demand for amino acid displayed by cancer cells is unconventionally exploited as a design principle to replete cancer cells with apoptosis inducing nanoscopic porous amino acid mimics (Nano‐PAAM). A small library consisting of nine essential amino acids nanoconjugates (30 nm) are synthesized, and the in vitro anticancer activity is evaluated. Among the Nano‐PAAMs, l ‐phenylalanine functionalized Nano‐PAAM (Nano‐pPAAM) has emerged as a novel nanotherapeutics with excellent intrinsic anticancer and cancer‐selective properties. The therapeutic efficacy of Nano‐pPAAM against a panel of human breast, gastric, and skin cancer cells could be ascribed to the specific targeting of the overexpressed human large neutral amino acid transporter SLC7A5 (LAT‐1) in cancer cells, and its intracellular reactive oxygen species (ROS) inducing properties of the nanoporous core. At the mechanistic level, it is revealed that Nano‐pPAAM could activate both the extrinsic and intrinsic apoptosis pathways to exert a potent “double‐whammy” anticancer effect. The potential clinical utility of Nano‐pPAAM is further investigated using an MDA‐MB‐231 xenograft in NOD scid gamma mice, where an overall suppression of tumor growth by 60% is achieved without the aid of any drugs or application of external stimuli.     

Simple high-performance liquid chromatographic method for determination of pentoxifylline in human plasma

A simple high-performance liquid chromatographic method using ultraviolet detection was developed for the determination of pentoxifylline in human plasma. Prior to analysis, pentoxifylline and the internal standard (chloramphenicol) were extracted from plasma sample using dichloromethane. The mobile phase comprised 0.02 M phosphoric acid adjusted to pH 4, methanol and tetrahydrofuran (55:45:1, v/v). Analysis was run at a flow-rate of 1.4 ml/min with the detector operated at a wavelength of 273 nm. The method was specific and sensitive with a detection limit of approximately 3.0 ng/ml at a signal to noise ratio of 3:1, while the limit of quantification was 12.5 ng/ml. Mean recovery value of the extraction procedure was about 99.9%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 10.0%. The calibration curve was linear over a concentration range of 12.5-400.0 ng/ml.     

Symmetry of bone mineral density in the hips is not affected by age

To assess the symmetry of bone mineral density (BMD) of the hips, we used dual photon absorptiometry (DPA) to asses BMD in 266 normal Chinese women in the bilateral femoral neck, trochanter and Ward's triangle regions. Linear regression analysis of the results showed excellent correlation between the hips. The correlation coefficients for the femoral neck, trochanter and Ward's triangle regions were 0.899, 0.892 and 0.935 respectively, and the standard errors of the estimate (S.E.E.) were 0.029, 0.027 and 0.022 g cm-2 respectively. Pooling the BMD data of corresponding regions (n = 532), the correlation coefficient was 0.813 for femoral neck versus trochanter, 0.889 for femoral neck versus Ward's triangle, and 0.833 for trochanter versus Ward's triangle. Further analysis showed mean correlation coefficients of 0.854 for elderly subjects (age > or = 65 years, n = 51) and 0.887 for younger subjects (age < 65 years, n = 215). In conclusion, assessment of left or right hip BMD may be used to represent the BMD of the contralateral hip and can reduce both the cost and radiation exposure during mass screening for osteoporosis.     

Preliminary study of a polycaprolactone membrane utilized as epidermal substrate

Solvent-cast sheets of polycaprolactone were biaxially stretched to produce 10–15 m thick films. PCL films were found to have a tensile strength of 55 MPa which is about two and a half times stronger than native skin. One of our previous studies using non-coated PCL membranes showed that only 36% of the membrane surface was covered with keratinocytes after 9 days of culture. The present study examined the effects of coating the surface of PCL membranes with fibrin on the proliferation of keratinocytes. Qualitative analysis revealed that the cells attached and proliferated better on coated PCL films. Keratinocytes exhibited healthy cobblestone morphology and proliferated as continuous monolayers over a period of 16 days. The results indicated that fibrin coated PCL films would support the attachment and proliferation of human keratinocytes and have the potential to be applied as a matrix material for tissue engineering an epidermal equivalent.     

Optimal adaptive controllers for unknown Markov chains

We consider the problem of adaptively controlling an unknown Markov chain. No prior information regarding the values of the transition probabilities is provided us (except for a list of forbidden, zero-probability transitions, which is usually obtained as a byproduct of the modeling process itself). The goal is to design an adaptive controller to adequately control the unknown system when its performance is measured by the average cost incurred over a long operating time period. Our main result is the exhibition of a family of adaptive controllers which, when applied to the unknown system, will result in a performance precisely equal to the optimal performance attainable if the system, i.e., the transition probabilities, were known. Hence, the adaptive controllers proposed here are truly optimal, even when operating on an unknown system. The results presented here extend similar results in [1] where we assume to be initially provided with a finite set of possible models, one of which is guaranteed to be the true one. This paper directly addresses those practical situations where a finite set of possible models with such a guarantee is hard to come by.