Providing Information Feedback to Bidders in Online Multi-unit Combinatorial Auctions

Bidders in online multi-unit combinatorial auctions face the acute problem of estimating the valuations of an immense number of packages. Can the seller guide the bidders to avoid placing bids that are too high or too low? In the single unit case, fast methods are now available for incrementally computing, for each package at each time instant, the recommended lower bound (Deadness Level) and upper bound (Winning Level) on the next bid. But when there are multiple units of items, it becomes difficult to compute the Deadness Level of a package accurately. An upper bound on this quantity can be derived however, and a bid that stays within this bound and the Winning Level is “safe”, in the sense that it is not wasted and has the potential to become a winning bid. What is now needed is an incremental procedure for speeding up the computation of this bound

Graph search methods for non-order-preserving evaluation functions: applications to job sequencing problems

AbstractGraph search with A∗ is frequently faster than tree search. But A∗ graph search operates correctly only when the evaluation function is order-preserving. In the non-orderpreserving case, no paths can be discarded and the entire explicit graph must be stored in memory. Such situations arise in one-machine minimum penalty job sequencing problems when setup times are sequence dependent. GREC, the unlimited memory version of a memory-constrained search algorithm of the authors called MREC, has a clear advantage over A∗in that it is able to find optimal solutions to such problems. At the same time, it is as efficient as A∗ in solving graph search problems with order-preserving evaluation functions. Experimental results indicate that in the non-order-preserving case, GREC is faster than both best-first and depth-first tree search, and can solve problem instances of larger size than best-first tree search

DEVELOPMENT AND EVALUATION OF SUSTAIN RELEASE MICROPARTICLES OF METOPROLOL SUCCINATE

Objective: In this study, xanthan gum was oxidized by sodium periodate to form xanthan dialdehyde. This oxidized gum was used as crosslinking agent as an alternative to somewhat toxic glutaraldehyde, the basis of which is the reaction between the Schiff reagent and the aldehydes formed by periodate oxidation. Methods: Formation of aldehyde groups were confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Microparticles of metoprolol succinate were fabricated using crosslinking of a chitosan/gelatin mix system by dialdehyde Xanthan gum. The properties of the developed microparticles were investigated with swelling equilibrium studies, differential scanning calorimeter (DSC), in vitro drug release studies and scanning electron microscopy (SEM). Results: The in vitro drug release from these microparticles was affected by total polymer amount, oxidation reaction time and chitosan to gelatin ratio. The cumulative percent release of metoprolol succinate was observed within the range of 46 to 95% at 8 h from different formulations studied. The factors identified as significant to produce any impact on drug loading as well as drug release were both the polymer and inter actions of polymer and Xanthan gum dialdehyde. Conclusion: The release mechanism followed the super case II model kinetics

INFLUENCE OF ORGANIC MANURES ON PRODUCTIVITY OF TWO VARIETIES OF RICE

Field experiment was conducted during 2003-04 to study the effect of vermicompost, farmyard manure and water hyacinth compost in comparison to chemically fertilized and unfertilized plots on crop-plants in HYV Swarna and local variety Magaisal. The experiment followed split plot design with two varieties of rice in the main plots and five nutrient sources randomized in sub plots. Signifi cant variation in grain yield between the varieties, among the nutrient sources and their interactions was observed. Grain yield recorded in HYV Swarna was higher to local variety Mugaisal irrespective of the treatments and hence Swarna was considered to be more tolerant to Mugaisal. Among the nutrient sources, treatment with vermicompost imparted maximum grain yield to all other nutrient sources irrespective of varieties

LANSIM and its applications to distributed EMS

Distributed energy management systems (EMS) open up a host of alternative design options. Simulation plays an important role in evaluating performance and in comparing alternative designs. Currently all the proposed distributed EMSs are local area network (LAN)-based. A LAN simulator, LANSIM, has been developed. To illustrate the application of LANSIM, comparisons are made with different distributed EMS configurations, different LAN technologies (Ethernet and FDDI), and different Ethernet implementations.published_or_final_versio

MODIFICATION OF GUMS BY PERIODATE OXIDATION: A NATURAL CROSS-LINKER

Scientists throughout the world are in search of novel modified biopolymer to fabricate smart drug delivery systems based on hydrogel formulations using several cross-linkers like glutaraldehyde, glyoxal, epichlorhydrin, adipic acid dihydrazide, carbodiimide, genipin, etc. Agents that are fused into the polymeric structure like isocyanates, glutaraldehyde, polyepoxides, etc., and are extremely toxic in nature. In addition, these are susceptible to percolate out into the body on biodegradation of polymeric structure. As an alternative to these toxic cross-linking agents, the periodate-Schiff base staining technique is widely being used for cross-linking in biology and biochemistry. The mechanism of this cross-linking technique is based on the reaction in-between the Schiff reagent and the aldehydes produced via the periodate oxidation. During the past few decades, several researchers have already been studied on the natural gums and also, developed their dialdehyde derivatives via the periodate oxidation technique. These periodate oxidized gums are being used to cross-link gelatin, other proteins and chitosan to develop various smart systems for drug delivery, tissue engineering, wound dressing, edible films, etc. The current review presents a comprehensive discussion of the available reported literature on the periodate oxidation of various gums and their use as natural cross-linker

Studies on Multifunctional Effect of All-Trans Retinoic Acid (ATRA) on Matrix Metalloproteinase-2 (MMP-2) and Its Regulatory Molecules in Human Breast Cancer Cells (MCF-7)

Background. Vitamin A derivative all-trans retinoic acid (ATRA) is considered as a potent chemotherapeutic drug for its capability of regulating cell growth and differentiation. We studied the effect of ATRA on MMP-2 in MCF-7, human breast cancer cells, and the probable signaling pathways which are affected by ATRA on regulating pro-MMP-2 activity and expression. Methods. Gelatin zymography, RT-PCR, ELISA, Western blot, Immunoprecipitation, and Cell adhesion assay are used. Results. Gelatin zymography showed that ATRA caused a dose-dependent inhibition of pro-MMP-2 activity. ATRA treatment downregulates the expression of MT1-MMP, EMMPRIN, FAK, NF-kB, and p-ERK. However, expression of E-cadherin, RAR, and CRABP increased upon ATRA treatment. Binding of cells to extra cellular matrix (ECM) protein fibronectin reduced significantly after ATRA treatment. Conclusions. The experimental findings clearly showed the inhibition of MMP-2 activity upon ATRA treatment. This inhibitory effect of ATRA on MMP-2 activity in human breast cancer cells (MCF-7) may result due to its inhibitory effect on MT1-MMP, EMMPRIN, and upregulation of TIMP-2. This study is focused on the effect of ATRA on MMP, MMP-integrin-E-cadherin interrelationship, and also the effect of the drug on different signaling molecules which may involve in the progression of malignant tumor development

FORMULATION DEVELOPMENT AND IN-VITRO EVALUATION OF SUSTAINED RELEASE MATRIX TABLETS OF SALBUTAMOL SULPHATE

ABSTRACT: The objective of the present study was to develop salbutamol sulphate matrix tablets, sustained release dosage form, for the treatment of Chronic Obstructive Pulmonary Disease (COPD). Simultaneous equations were formed to calculate the concentration values of Salbutamol sulphate and drug compatibility study was performed through Infrared spectroscopy. The matrix tablets were prepared by wet granulation method using two hydrophobic polymers such as Ethyl cellulose and Acrycoat S-100 in varying ratios. The granules exhibited satisfactory rheological demeanor. All the seven tablet formulations showed acceptable pharmacotechnical properties and complied with the in-house specifications for tested parameters. The results of formulation F-4 (Ethyl cellulose and Acrycoat in 2:1 ratio) could extend the release of Salbutamol sulphate up to 12 hr and was found comparable to marketed sustained release products. Model fitting analysis (Zero order, Higuchi and Korsmeyer-Peppas model) for all the formulations were performed and it was seen that all the formulations predominantly follow the Higuchi model. While comparing with the ‘n’ values of all the formulations of Korsmeyer-Peppas model, Fickian/Diffusion controlled release was observed in case of F-4 and F-5, whereas for the other formulations non-Fickian transport was observed

Asymmetric Response in Foreign Exchange Volatility under Structural Break

This paper considers the embedded dynamics of conditional volatility in five selected exchange rates vis-à-vis Indian Rupee. Specifically, it explores the possible asymmetric response of volatility towards good and bad news and inquires whether it is sensitive to breaks in volatility. Using a suitable GARCH family model no asymmetric response of volatility is found when structural breaks were ignored. However, once the breaks in volatility are incorporated, significant asymmetric volatility response and leverage effects could be detected in all five selected exchange rates. Leverage effects have been strong in the years following the currency crisis of 1997-98, for four out of the five exchange rates. The same phenomenon recurs during the recent recovery after the financial crisis of 2007-08. Thus, during recovery, with the shocks of crisis still in the mind of the investors, bad news tends to exert greater impact on volatility than the good ones

Asymmetric Response in Foreign Exchange Volatility under Structural Break

This paper considers the embedded dynamics of conditional volatility in five selected exchange rates vis-à-vis Indian Rupee. Specifically, it explores the possible asymmetric response of volatility towards good and bad news and inquires whether it is sensitive to breaks in volatility. Using a suitable GARCH family model no asymmetric response of volatility is found when structural breaks were ignored. However, once the breaks in volatility are incorporated, significant asymmetric volatility response and leverage effects could be detected in all five selected exchange rates. Leverage effects have been strong in the years following the currency crisis of 1997-98, for four out of the five exchange rates. The same phenomenon recurs during the recent recovery after the financial crisis of 2007-08. Thus, during recovery, with the shocks of crisis still in the mind of the investors, bad news tends to exert greater impact on volatility than the good ones