Large deviations for random walks in a mixing random environment and other (non‐Markov) random walks

We extend a recent work by S. R. S. Varadhan [8] on large deviations for random walks in a product random environment to include more general random walks on the lattice. In particular, some reinforced random walks and several classes of random walks in Gibbs fields are included. © 2004 Wiley Periodicals, Inc.     

99mTc—Sulphur colloid: A freeze-dried,single-step kit for liver imaging

The formulation of a freeze-dried sulphide colloid kit, to be directly labelled with technetium is based on the preparation of tin/II/ sulphide precolloid, stabilized with carboxy methyl cellulose. The formation kinetics of the labelled colloid assessed by GCS-method showing a fast reduction of^99mTc-pertechnetate, forming reduced^99mTc-colloid with subsequent build-up of the labelled sulphur colloid. This is assumed to be due to the formation of^99mTc/V/ to be bound to sulphide precolloid of the kit. The blood clearance data of the labelled colloid in rabbits showed two exponential disappearance phases of radioactivity from blood with biological half times of 3 and 67 min. The results of organ distribution in mice show that more than 85% of the administered activity is accumulated in the liver indicating a high colloidal yield of optimal particle size. The dynamic studies of the labelled colloid achieved in normal subjects using gamma camera indicate a rapid blood clearance and high liver uptake with low surrounding tissue background.This work was performed under the auspices of the Iraqi Atomic Energy Organization and presented in part at the Fifth International Symposium on Radiopharmaceutical Chemistry, Tokyo, August 1984.     

Technetium-99m-diethyl-IDA instant kit: Labelling kinetics and biological properties

A formulation of stannous-diethyl-IDA freeze-dried kit, containing 50 mg diethyl-IDA and 0.4 mg hydrated stannous chloride, to be labelled with technetium has been developed for hepatobiliary scintigraphy. Gel chromatography column scanning technique has been applied for determination of technetium fractions in the preapration. The optimal pH value of the preparation with a high hepatobiliary specificity was found between 5.5 to 6.0. Effect of ligand to metal ratio on the stability of the prepared Sn-diethyl-IDA solution prior mixing with technetium has been investigated. The reaction conditions (initial pH) between the ligand and stannous ion affects the percent hydrolysis of the labelled compund, i.e. the formation rate of the complex. The organ distribution data of^99mTc-diethyl-IDA in mice for 60 minutes post injection were satisfactory. The radiopharmaceutical exhibits rapid blood clearance, great hepatic clearance and very short hepatocyte transit time. Uptake of the radiopharmaceutical in various organs of mouse at 5 minute post injection showed that the greater part of the injected radioactivity has distributed between liver and intestine. However, about 12% and 60% of the injected dose has been found in liver and intestine respectively. The renal uptake of the HB agent in mice is relatively low and decreases with time to become about 0.3% at 60 minutes post injection. Blood clearance data of the radiopharmaceutical kit in rabbits showed that the HB agent is-rapidly cleared, since the initial decrease was very fast with a half-time of 1.5 minutes.     

Prescriptive analytics for FIFA World Cup lodging capacity planning

The FIFA World Cup, comprising sixty-four matches spanning an entire month, has, in recent years, been attended by about three million spectators of which over half a million are visitors requiring lodging. Planning lodging capacity for an event of this magnitude is necessary for host nations where pre-existing infrastructures are either inadequate or lacking. This paper develops an optimization analytics framework that sequentially employs two integer programming models for foreign spectator analysis and the consequent lodging requirements. The framework is applied to assess the preparedness of lodging infrastructure in Qatar for FIFA 2022.     

Distress among disaster-affected populations: delay in relief provision

Central to humanitarian logistics is the minimization of distress among impacted populations in the aftermath of a disaster. In this paper, we characterize two levels of distress, termed criticality and destitution, with respect to the delay provision of relief items. Delay in provision of a relief item will lead to destitution for a tolerable number of days, beyond which it will lead to criticality. We develop a mixed-integer goal program that quantifies these two metrics with respect to the number of days without provision of each of a set of relief items. The model determines the allocation of resources and the distribution of available relief items in a manner that minimizes criticality and destitution in affected population segments. The use of the model is demonstrated for the aftermath of a catastrophic earthquake in Istanbul, expected to occur by 2030.     

Simultaneous determination of gliquidone, pioglitazone hydrochloride, and verapamil in formulation and human serum by RP-HPLC

In the present study, a reverse-phase high performance liquid chromatography method was developed, validated and applied for the simultaneous determination of gliquidone, pioglitazone hydrochloride and verapamil in tablets and human serum. Chromatographic separation was achieved on a C18 column (5 μm, 25 × 0.46 cm) with a mobile phase consisting of methanol-water-acetonitrile (80:10:10 v/v/v) with a flow rate of 0.7 mL/min and pH adjusted to 3.50 with phosphoric acid at 230 nm. Glibenclamide was used as internal standard. The experimentally derived limit of detection and limit of quantitation were determined to be 0.24, 0.93, 0.40, and 0.80, 3.11, 1.36 μg/mL for gliquidone, pioglitazone, and verapamil, respectively. There were no interfering peaks due to the excipients present in the pharmaceutical tablets. Thus, the proposed method is simple and suitable for the simultaneous analysis of active ingredients in dosage forms and human serum.     

Micro-wires self-assembled and 3D-connected with the help of a nematic liquid crystal

We discuss a method for producing automatic 3D connections at right places between substrates in front of one another. The idea is based on the materialization of disclination lines working as templates. The lines are first created in the nematic liquid crystal (5CB) at the very place where microwires have to be synthesized. Due to their anchoring properties, colloids dispersed into the nematic phase produce orientational distortions around them. These distortions, which may be considered as due to topological charges, result in a nematic force, able to attract the colloids towards the disclinations. Ultimately, the particles get trapped onto them, forming micro- or nano-necklaces. Before being introduced in the nematic phase, the colloids are covered with an adhering and conducting polypyrrole film directly synthesized at the surface of the particles (heterogeneous polymerization). In this manner, the particles become conductive so that we may finally perform an electropolymerization of pyrrole monomers solved in 5CB, and definitely stick the whole necklace. The electric connection thus synthesized is analyzed by AFM, and its strength is checked by means of hydrodynamic tests. This wiring method could allow Moore's law to overcome the limitations that arise when down-sizing the electronic circuits to nanometer scale.     

Determination of tryptophan in raw materials, rat brain and human plasma by RP-HPLC technique

This paper describes tryptophan (TRP) estimation in raw human plasma and rat brain by reversed-phase high-performance liquid chromatography (RP-HPLC). Estimation was carried out on a Purospher STAR C18 column using water-acetonitrile (90:10 v/v, at pH 2.7) mixture at a rate of 1.5 mL/min as mobile phase. Eluents were monitored at 273 nm by an ultraviolet detector. The method was linear (R(2) > 0.999), precise (intra-day and inter-day precision <2%) in the range of 0.25-20 μg/mL. The detection and quantification limits were 0.0144 μg/mL and 0.0437 μg/mL, respectively. In human plasma, Day 1 and Day 2 precision were 0.054-2.29% and 1.66-3.7%; whereas precisions in rat brain were 1.23-2.3% and 0.677-4.2%, respectively. The method was applied to study TRP level in human smokers and in arthritic rat brain. An efficient RP-HPLC method was developed for TRP determination that worked for clinical and research purposes.