bluuebunny/crossref_metadata_2025 huggingface dataset:
The scavenging of superoxide radicals promotes apoptosis induced by a novel cell-permeable fusion protein, sTRAIL:FeSOD, in tumor necrosis factor-related apoptosis-inducing ligand-resistant leukemia cells
Authors: Tang Hongyun , Qin Yong , Li Jianyong , Gong Xingguo
Published: March 2011

Background

Many cancer cells develop resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, necessitating combination with chemotherapy, and normal cells manifest side effects due to the combined treatment regimen of TRAIL and chemotherapeutic drugs. A novel cancer therapy utilizing TRAIL is thus urgently needed.

Results

In this study, we exploited TRAIL receptor-mediated endocytosis for the first time to produce a cell-permeable molecule, soluble forms of recombinant TRAIL:iron superoxide dismutase (sTRAIL:FeSOD), which possesses sTRAIL-induced apoptotic ability and FeSOD antioxidant activity. The FeSOD component was rapidly introduced into the cell by sTRAIL and intracellular superoxide radical (O2
-), which have been implicated as potential modulators of apoptosis in cancer cells, was eliminated, resulting in a highly reduced cellular environment. The decrease in cellular O2
-, which was accompanied by a brief accumulation of H2O2 and downregulation of phosphorylated Akt (p-Akt) and cellular FLICE-inhibitory protein, sensitized K562 leukemia cells and human promyelocytic leukemia (HL-60) cells to TRAIL-induced apoptosis. The low H2O2 levels protected human LO2 hepatocytes from sTRAIL:FeSOD-induced apoptosis despite downregulation of p-Akt. We also obtained evidence that the lack of response to sTRAIL:FeSOD in normal T cells occurred because sTRAIL:FeSOD shows much stronger shifts of redox state in erythroleukemia (K562) and HL-60 cells compared to that in normal T cells. K562 and HL-60 cells underwent sTRAIL:FeSOD-induced apoptosis without the dysfunction of mitochondria.

Conclusions

The fusion protein overcomes the inability of FeSOD to permeate the cell membrane, exhibits synergistic apoptotic effects on K562 and HL-60 cells and demonstrates minimal toxicity to normal T cells and the normal liver cell line LO2, indicating its potential value for the treatment of leukemia.
Eschar and neck lymphadenopathy caused by Francisella tularensis after a tick bite: a case report
Authors: Edouard Sophie , Gonin Khira , Turc Yves , Angelakis Emmanouil , Socolovschi Cristina , Raoult Didier
Published: March 2011

Introduction

In 25 to 35% of cases, the aetiological agent of scalp eschar and neck lymphadenopathy after a tick bite remains undetermined. To date, Rickettsia slovaca, Rickettsia raoultii and more recently Bartonella henselae have been associated with this syndrome.

Case presentation

A four-year-old Caucasian boy was admitted to hospital with fever, vomiting and abdominal pain. On physical examination, an inflammatory and suppurating eschar was seen on the scalp, with multiple enlarged cervical lymph nodes on both sides. Although no tick was found in this scalp lesion, a diagnosis of tick-borne lymphadenopathy was suggested, and explored by serology testing and polymerase chain reaction of a biopsy from the eschar. Francisella tularensis DNA was found in the skin biopsy and the serology showed titres consistent with tularaemia.

Conclusion

This is, to the best of our knowledge, the first reported case of scalp eschar and neck lymphadenopathy after tick bite infection caused by F. tularensis.
Adalimumab - an effective and promising treatment for patients with fistulizing Crohn's disease: a case series
Authors: Kouklakis George , Efremidou Eleni I , Zezos Peter , Liratzopoulos Nikolaos , Souftas Vassilios D , Gatopoulou Anthia , Simopoulos Konstantinos , Manolas Konstantinos J
Published: March 2011

Introduction

Crohn's disease is a chronic inflammatory bowel disease of unknown etiology which may affect any part of the bowel. Fistulas are a common and often serious complication of Crohn's disease. The treatment for fistulizing Crohn's disease can be medical, surgical or a combination of the two. Recently, adalimumab, a fully human anti-tumor necrosis factor monoclonal antibody, has been suggested as a safe and effective treatment for the induction and maintenance of remission in adult patients with moderate to severe Crohn's disease, who are refractory to conventional therapy or intolerant to infliximab. However, large studies focusing on evaluating the efficacy of adalimumab in fistulizing Crohn's disease have not yet been published.

Case presentation

We report the cases of three patients, of European Caucasian ethnicity and Greek nationality, with active luminal and fistulizing Crohn's disease. All of the cases were treated successfully with adalimumab. Patient 1 (a 44-year-old man) and patient 2 (an 18-year-old woman) developed early post-surgical enterocutaneous fistulas, while patient 3 (a 20-year-old woman) had peri-anal fistulizing Crohn's disease. Adalimumab treatment (160 mg subcutaneously at week zero, 80 mg at week two, and 40 mg every other week) was used for three different indications: (1) after the failure of other conservative medical treatments for Crohn's disease (patient 1); (2) as a monotherapy in treating a naive patient (patient 2); (3) after an intolerance to infliximab (patient 3). A remission of the active luminal and fistulizing disease was achieved soon after the initiation of adalimumab and sustained thereafter with maintenance doses. No further surgical intervention was required and no adverse effects were observed in any of the cases.

Conclusions

Fistulizing Crohn's disease remains a challenge in clinical practice. Adalimumab seems to be an effective, well-tolerated and safe treatment option for the induction and maintenance of remission in patients with moderate to severe peri-anal fistulizing Crohn's disease. Furthermore, adalimumab seems to be a promising treatment option for patients with moderate to severe fistulizing Crohn's disease with enterocutaneous fistulas. However, this clinical observation needs to be investigated in further clinical trials.
Abscopal effect of radiation on lung metastases of hepatocellular carcinoma: a case report
Authors: Okuma Kae , Yamashita Hideomi , Niibe Yuzuru , Hayakawa Kazushige , Nakagawa Keiichi
Published: March 2011

Introduction

The abscopal effect is the effect of radiation therapy at a site distant to the area of irradiation. This is not a common event and has not been clearly defined, resulting in few reported cases in the literature. We discuss this phenomenon in a patient with hepatocellular carcinoma.

Case presentation

A 63-year-old Japanese man underwent extended right hepatic lobectomy for hepatocellular carcinoma. During his follow-up examination, a single lung metastasis and a single mediastinal lymph node metastasis were found. Trans-catheter arterial embolization was initially attempted to treat the mediastinal tumor, however this approach failed to take effect and carried risks of spinal artery embolism. External-beam irradiation, with a dose of 2.25 Gy per fraction, was performed using an antero-posterior parallel-opposed technique (total dose, 60.75 Gy). A computed tomography scan performed one month after starting radiotherapy showed a remarkable reduction of the mediastinal lymph node metastasis. In addition to this, we observed spontaneous shrinking of the lung metastasis, which was located in the right lower lobe and out of the radiation field. No chemotherapy was given during the period. There has been no recurrence of either the lung metastasis or the mediastinal lymph node metastasis during a follow-up 10 years after the radiotherapy.

Conclusion

We observed a rare abscopal effect in a site distant from the area of irradiation. Irradiation of the mediastinum resulted in tumor mass regression in the untreated lung tumor.
Effects of Surface Curvature and Surface Strength on Argon Adsorption in Carbon Nanotubes at Temperatures below the Triple Point
Authors: Liu Zhongjun , Do D.D. , Nicholson D. , Xi Zhengping
Published: March 2011

This paper describes an investigation of argon adsorption into carbon nanotubes at temperatures below the triple point, using a grand canonical Monte Carlo simulation to study the effects of confinement and surface strength on the 2D transition. In large pores, it was found that 2D transitions can occur in more than one layer, but are absent in higher layers for small pores. The 2D critical temperature of the first layer for a small pore (R = 1.2 nm) was found to be ca. 66 K (MWCNT) and 65 K (SWCNT), compared to 55–59 K observed experimentally for a flat graphite surface. This is because of the overlapping effects due to the surface curvature or the confinement in a carbon nanotube. Assuming a weaker carbon surface by reducing the graphene surface strength by 40% for SWCNT, the 2D critical temperature was only modestly reduced to 63 K. This suggests that the experimental data at 59 K might be attributed to other factors, other than confinement effects. An imperfect surface is suggested and, employing 5% defects on this surface, the 2D critical temperature has been determined as 58 K which is in better agreement with the experimental value of 59 K.
Accurate Fit and Thermochemical Analysis of the Adsorption Isotherms of Methane in Zeolite 13X
Authors: Llano-Restrepo Mario
Published: March 2011

The recovery of methane from landfill gases and coal mines has become of the utmost importance because methane has a global-climate warming potential much higher than that of carbon dioxide. Zeolite 13X is widely used for the separation of methane and carbon dioxide from such sources. Accurate fits of the adsorption isotherms of methane in zeolite 13X are required for the rigorous simulation of that separation. In this work, a generalized statistical thermodynamic adsorption (GSTA) model has been used to obtain a very accurate correlation of a published set of adsorption isotherms of methane in zeolite 13X that were measured from 120 K to 273 K over the pressure range 0.07 Pa to 12.2 MPa. In contrast, none of five traditional adsorption models was capable of fitting these isotherms. A thermochemical interpretation of the correlation is provided and predictions for the isosteric heat of adsorption are made, which turn out to be in excellent agreement with the available experimental data.
Removal of Trihalomethanes from Aqueous Solution through Adsorption and Photodegradation
Authors: Yakout S.M.
Published: March 2011

Trihalomethanes (THMs) are carcinogenic by-products of disinfection that are present in drinking water. In the present research, adsorption and photodegradation, either individually or in tandem, were employed for the removal of the principal THMs found in water supply systems. The effects of pH, contact time, adsorbents and adsorbate concentration on the adsorption system were investigated. The Langmuir and Freundlich adsorption isotherm models were used to analyze the resulting adsorption data. Photodegradation of THMs was carried out in the presence and absence of activated carbon. The integration of adsorption and photodegradation systems as a hybrid treatment process resulted in a synergetic enhancement of the THM removal efficiency. The kinetics of THM removal were found to follow the pseudo-second-order model rather than the Langmuir–Hinshelwood pseudo-first-order model.
Adsorptive Removal of Phosphate Ions Using Leached Sea Nodule Residue Generated by the Reduction–Roasting Ammoniacal Leaching Process
Authors: Behera R.K. , Satapathy P.K. , Randhawa N.S. , Das N.N.
Published: March 2011

The present study was an attempt to find an alternative use for the leached residue generated after the selective extraction of Cu(II), Ni(II) and Co(II) ions during the reduction–roasting ammoniacal leaching of Indian Ocean sea nodules, so that the latter may be used as an adsorbent for the removal of phosphate ions from aqueous media. Physicochemical characterization revealed that the leached residue was a complex mixture of oxides of mainly manganese and iron along with MnCO3. Adsorption studies of the water-washed leached residue (WSNR), varying the pH, phosphate ion concentration, WSNR dosage, heat treatment and the presence of interfering anions in solution, indicated that phosphate (P) ion uptake increased with increasing heat-treatment temperature and pH, to attain a maximum value at 400 °C and a pH value of ca. 5.0, but thereafter decreased on increasing the heat-treatment temperature and pH further. The adsorption data were best fitted by the Freundlich isotherm model. Desorption studies showed that < 90% of the adsorbed phosphate ions could be desorbed from WSNR after stirring at pH ≥ 10.0 for 2 h. The results obtained could be useful in a consideration of the use of WSNR as an adsorbent for the removal of phosphate ions from contaminated water bodies.
Preparation, Characterization and Performance of a Novel Surface-Imprinting Polymer for the Adsorption of Dibenzothiophene
Authors: Huang Weihong , Zhou Wei , Xu Wanzhen , Xu Pingping , Xu Xiangjun , Yan Yongsheng
Published: March 2011

A novel surface-imprinting polymer (MIP/K2Ti6O13) was prepared using potassium hexatitanate whiskers (K2Ti6O13) as the carrier employing electrostatic interaction and π–π interaction between the template molecule [dibenzothiophene (DBT)] and the functional monomer [4-vinylpyridine (4VP)]. The synthetic polymer was characterized via Fourier-transform infrared (FT-IR) spectroscopy, surface area and porosity analysis, and X-ray diffraction (XRD). Static adsorption experiments were conducted to evaluate the adsorption kinetics, adsorption isotherms and adsorption selectivity of MIP/K2Ti6O13. Adsorption kinetic studies revealed that a contact time of 300 min was necessary to attain equilibrium. Adsorption isotherm studies indicated that the capacity of MIP/K2Ti6O13 towards the adsorption of DBT at 298 K, 308 K and 318 K was 16.18 mg/g, 22.74 mg/g and 29.89 mg/g, respectively. Selectivity experiments showed that the adsorption capacity of DBT on MIP/K2Ti6O13 was greater than for the other three analogues, while the imprinting factor towards DBT (α) was 2.06.
Use of Oxalic Acid-Modified Rice Husk for the Adsorption of Neutral Red from Aqueous Solutions
Authors: Zou Weihua , Bai Hongjuan , Li Ke , Shi Xiaolan , Han Runping
Published: March 2011

Rice husk modified with oxalic acid (MRH) was tested as a lowcost adsorbent for the removal of Neutral Red (NR) dye from aqueous solutions employing batch adsorption procedures. Such studies were conducted by varying various parameters such as the pH, the adsorbent dosage, the salt concentration, the contact time, the concentration of the adsorbate and the temperature. The kinetic experimental data were analyzed using three kinetic equations, viz. the pseudo-first-order equation, the pseudo-second-order equation and the intra-particle diffusion model equation, to examine the mechanism of adsorption and the potential rate-controlling step.

The mechanism of the process was found to be complex, consisting of both surface adsorption and pore diffusion. The values of the effective diffusion parameter, Deff, were estimated to be of the order of 10−8 cm2/s, indicated that intra-particle diffusion was not the rate-controlling step. The equilibrium adsorption data obtained at various temperatures were analyzed using the Langmuir, Freundlich and Redlich–Peterson isotherm models using non-linear regressive analysis. The equilibrium adsorption results were better fitted by the Langmuir and Redlich–Peterson isotherms relative to the Freundlich model. Calculated thermodynamic parameters showed that the adsorption of NR onto MRH was feasible, spontaneous and endothermic under the studied conditions. The carboxyl groups on the surface of the modified rice husk (MRH) were primarily responsible for the sorption of NR. It is suggested that MRH may be suitable as an adsorbent material for adsorbing NR from aqueous solutions.
Adsorptive Removal of Reactive Yellow 15 from Aqueous Solution by Coconut Coir Activated Carbon
Authors: Khan Taimur , Kutty Shamsul Rahman Mohamed , Chaudhuri Malay
Published: March 2011

Activated carbon was prepared from coconut coir and its ability to adsorb Reactive Yellow 15 (RY15) dye examined. Batch adsorption tests showed that the extent of dye adsorption depended on the initial dye concentration, the contact time and the pH value of the solution. Equilibrium adsorption was attained within 240 min, with maximum adsorption occurring at a pH value of 2. The adsorption capacity of the activated carbon towards the dye was evaluated and compared with that of a commercial activated carbon. Equilibrium adsorption data for the coconut coir activated carbon (CCAC) and the commercial activated carbon (CAC) were well described by the Langmuir and Freundlich isotherm models, and indicated the higher adsorption capacity of CCAC. The adsorption of RY15 by CCAC and CAC followed pseudo-second-order kinetics. The results indicate that activated carbon prepared from coconut coir is more effective than CAC for the adsorption of RY15. Hence, CCAC would be a suitable substitute for CAC in the removal of Reactive dyes from aqueous solution.
A Review of Decision Support Models for Offshore Wind Farms with an Emphasis on Operation and Maintenance Strategies
Authors: Hofmann Matthias
Published: March 2011

Plans to build a large number of offshore wind farms have created a need for decision support in the planning process to choose the most cost-efficient alternatives. This paper gives an overview of existing commercial as well as non-commercial decision support models along with their main characteristics. It focuses mainly on operation and maintenance, but also covers offshore logistics, power production and total project cost to a limited extent. The models were found through an extensive search of published literature, research organizations, research projects, and consulting companies. The search detected 49 models that address parts of the life cycle or the whole life cycle of an offshore wind farm.
The Behavior of Fixed Point Iteration and Newton-Raphson Methods in Solving the Blade Element Momentum Equations
Authors: McWilliam Michael , Crawford Curran
Published: March 2011

There is a substantial body of ongoing research improving the Blade Element Momentum (BEM) theory and applying it to the optimization of wind turbine rotors. Both of these developments challenge the suitability of fixed point iteration schemes being applied to advanced BEM models. This article explores the mathematical behavior of the BEM equations, with special attention to the application of numerical methods. Under special conditions, multiple solutions will exist when the airfoil is stalled. This situation gives increased uncertainty, where uncertainty in airfoil behavior is already high. This also demonstrates that there could be circumstances where the wake state has weak dependence on blade state. Fixed point iteration and Newton-Raphson numerical methods are investigated in this paper. Both methods will become unstable under certain conditions. The investigation shows that the Newton-Raphson method has well defined conditions for instability in terms of design variables and airfoil properties. By comparison, the fixed point function used here exhibits instability over a larger range.
A Neural Network Solution for Extrapolation of Wind Speeds at Heights Ranging for Improving the Estimation of Wind Producible
Authors: Cheggaga Nawal , Ettoumi Fatiha Youcef
Published: March 2011

This paper uses data collected by weather stations to develop coupled approach measurements numerical modeling for improving the estimation of wind produciblity. The work aims at improving the foundations for a prediction of a wind profile of quality, at short and long terms. This paper begins with a comparison between different actual methods of extrapolation wind speed, and then describes an artificial neural network (ANN) approach for the vertical wind speed extrapolation at the height of 50 m. The outputs of models are compared with the real measured data so the results show a significant improvement. Finally, a vertical wind speed profile is generated.
Ultra-Short Term Wind Power Prediction Model Based on Modified Grey Model Method for Power Control in Wind Farm
Authors: Zhang Zhen. Zhen , Zou Jian. Xiao , Zheng Gang
Published: March 2011

With the increasing significance of the power control in wind farms for modern power system, the precise ultra-short term wind power prediction are necessary for achieving the integrated active power control of practical wind farms. This paper focus on the wind power online prediction using the relationship between the wind speed and the wind power generation by ultra-term wind speed forecasting. An improved GM (Grey Model) rolling model is developed in the paper for the ultra-short term wind speed prediction. The simulation results have verified that the developed GM rolling model with the weaken buffer operator for the variable wind data preparation has better prediction performance over the traditional GM rolling model and adaptive alpha-based GM rolling model. This result will obviously optimize the wind power control in the wind farm by predicting the precise wind power generation in real time.
Development of a Portable Wind Generator Prototype
Authors: López Luis M. , Pinilla Alvaro E.
Published: March 2011

This paper presents the development of a portable wind generator prototype intended as a battery charger. The work begins with the optimal aerodynamic design of the rotor, based on the atmospheric conditions of the future installation locations, followed by manufacturing and testing to validate its expected performance. It was then coupled to a permanent magnet generator (PMG), and the performance of the whole wind charger was finally characterized, comparing the results with the measured performance of a similar commercial wind charger. All tests were executed in an open section wind tunnel.
Electrical Starter System for an H-Rotor Type VAWT with PM-Generator and Auxiliary Winding
Authors: Kjellin Jon , Bernhoff Hans
Published: March 2011

In order to operate a modern wind turbine an effective start procedure is required. This article presents an electrical start for a VAWT which is shown to have advantages over an aerodynamic start. An electrical starter for a 12 kW VAWT has been designed and built. The starter is based on a six-step modulated inverter that is feedback-controlled by the rotor position. The inverter is connected to an auxiliary winding in the generator to separate the starter electronics from the main system. The system has been simulated and experimentally verified in the wind turbine setup.
Power Electronics Reliability Comparison of Grid Connected Small Wind Energy Conversion Systems
Authors: Arifujjaman Md , Iqbal M.T. , Quaicoe J.E.
Published: March 2011

This work presents a power electronics reliability comparison of the power conditioning system for both the Permanent Magnet Generator (PMG) and Wound Rotor Induction Generator (WRIG)-based small Wind Energy Conversion Systems (WECS). The power conditioning system for grid connection of the PMG-based system requires a rectifier, boost converter and a grid-tie inverter, while the WRIG-based system employs a rectifier, a switch and an external resistor in the rotor side with the stator directly connected to the grid. Reliability of the power conditioning system is analyzed for the worst case scenario of maximum conversion losses at a predetermined wind speed. The analysis reveals that the Mean Time Between Failures (MTBF) of the power conditioning system of a WRIG-based small wind turbine is much higher than the MTBF of the power conditioning system of a PMG-based small wind turbine. The investigation is extended to identify the least reliable component within the power conditioning system for both systems. It is shown that the inverter has the dominant effect on the system reliability for the PMG-based system, while the rectifier is the least reliable for the WRIG-based system. This research indicates that the WRIG-based small wind turbine with a simple power conditioning system is a much better option for small wind energy conversion system.
A 3D Numerical Mode for HST Induced Vibrations
Authors: Galvín Pedro , Domínguez José
Published: March 2011

A general numerical model for the analysis of soil motion due to high-speed train passage and effects on nearby surface and underground structures is presented in this paper. In contrast to other existing approaches, effects on a particular structure and the influence of non-uniform soil conditions along the track can be evaluated. Numerical results are obtained for different situations and some of them are compared with existing experimental records. The experimental values are to a large extent reproduced by the present numerical approach.
Noise Exposure of Physical Education and Music Teachers
Authors: Maffei Luigi , Iannace Gino , Masullo Massimiliano
Published: March 2011

For teachers, as well as for many other non-industrial categories of workers, noise exposure was for long time considerate a negligible risk. In the last decade, however, many researchers have investigated the problem. These have underlined that for physical education and music teachers can subsist not only uncomfortable, but also unacceptable and risky noise exposures which can induce hearing problems and stress. The noise exposure levels are nevertheless very variable both for physical education teachers and for music teachers and depend on many factors. In this article an analysis of the noise exposure levels on 75 physical education teachers of 18 schools and of 9 music teachers of a academy of music are presented. The results show that a percentage of 20–25% PE teachers can reach a weekly noise exposure higher than 80 dB(A) while for 7 of the 9 music teachers the noise exposure during a normal working week can exceed the limit value of 87 dB(A).
Quantifying Whole Body Vibration Exposures in Metropolitan Bus Drivers: An Evaluation of Three Seats
Authors: Blood Ryan P. , Johnson Peter W.
Published: March 2011

The objective of this study was to evaluate three seats amongst a population of metropolitan bus drivers as they drove a standardized test route including city streets, old and new freeways, and a street segment containing ten large speed humps. Three comparisons were made: 1) comparing seats made by different manufactures (Seat 1 and Seat 2), 2) comparing seats with a standard foam (Seat 2) and silicone foam (Seat 3) seat pans, and 3) comparing WBV exposures based on road types. Whole body vibration (WBV) exposures were measured using a tri-axial seat pan accelerometer and the attenuation capabilities of each seat were evaluated by comparing the vibrations measured at the floor and seat of the bus. There were significant WBV exposure differences between the various street types, which were shown across all seat types. The city street and older freeway segments had the highest WBV exposures with both segments producing WBV exposures slightly above the action limit for Vibration Dose Value (VDV(8)). Relative to Seat 2, Seat 1 performed better at attenuating impulsive and shock related WBV exposures, however, neither seat performed significantly better when Average Vibration (Aw(8)) and VDV(8) WBV exposures were compared. In addition, no performance differences were seen between the standard foam (Seat 2) and silicone foam (Seat 3) seat pans. This study provided a unique opportunity to explore WBV exposures among bus drivers and potential ergonomic interventions in the way of seat options to reduce WBV exposures and potentially reduce workplace injuries.
Deterring the Smuggling of Nuclear Weapons in Container Freight Through Detection and Retaliation
Authors: Haphuriwat Naraphorn , Bier Vicki M. , Willis Henry H.
Published: March 2011

Concerns about terrorists smuggling nuclear bombs into the United States in container freight have led to demands for 100% inspection at either U.S. or foreign ports. However, under some circumstances, it may be possible to deter nuclear smuggling attempts with less than 100% inspection. Based on publicly available data, we quantify a game-theoretic model of terrorist decision making to understand the role of nuclear detection technologies in deterring nuclear terrorism. The results suggest that unless the defender imposes high retaliation costs on the attacker, 100% inspection is likely to be needed, and deterrence with partial inspection may not be achievable in practice even though it is possible in theory. On the other hand, when the defender can credibly threaten the attacker with costly retaliation, partial inspection may be sufficient to deter nuclear smuggling attempts. Sensitivity analysis of these results indicates that these observations are robust to assumptions about specific parameters in the model. Thus, for policy debates about how to prevent nuclear terrorism, consideration of the diplomatic stance on retaliation is as important as, or maybe even more important than, debate about the optimal percentage of containers to inspect.
An Integer Optimization Approach to Large-Scale Air Traffic Flow Management
Authors: Bertsimas Dimitris , Lulli Guglielmo , Odoni Amedeo
Published: March 2011

This paper presents a new integer programming (IP) model for large-scale instances of the air traffic flow management (ATFM) problem. The model covers all the phases of each flight—i.e., takeoff, en route cruising, and landing—and solves for an optimal combination of flow management actions, including ground-holding, rerouting, speed control, and airborne holding on a flight-by-flight basis. A distinguishing feature of the model is that it allows for rerouting decisions. This is achieved through the imposition of sets of “local” conditions that make it possible to represent rerouting options in a compact way by only introducing some new constraints. Moreover, three classes of valid inequalities are incorporated into the model to strengthen the polyhedral structure of the underlying relaxation.

Computational times are short and reasonable for practical application on problem instances of size comparable to that of the entire U.S. air traffic management system. Thus, the proposed model has the potential of serving as the main engine for the preliminary identification, on a daily basis, of promising air traffic flow management interventions on a national scale in the United States or on a continental scale in Europe.
Strategic Design and Analysis of a Relay Network in Truckload Transportation
Authors: Üster Halit , Kewcharoenwong Panitan
Published: March 2011

The truckload industry faces a serious and chronic problem of high driver turnover rate—typically more than 100%—with staggering associated costs. Among the major causes of this problem are extended on-the-road times where drivers handle several truckload pickup and deliveries successively; nonregular schedules and get-home rates; and low utilization, i.e., less mileage/unit-time per driver, which leads to low pay.

We consider the strategic design of a relay network that may potentially help to alleviate this problem by providing an efficient underlying network that facilitates an assignment of drivers to home bases (domiciles to which they stay close) and generation of more predictable schedules with continuity and higher get-home rates. In relay network design, we are interested in determining a number of relay point locations, assigning network nodes to these relay points (i.e., defining domiciles), and determining the actual route (from the origin to the destination) for each truckload on the network. In doing so, we explicitly consider driver tour lengths, load imbalance at relay points, and the percentage circuity constraints.

We develop an efficient Benders' decomposition-based algorithm that is significantly enhanced via strengthened Benders' cuts, cut disaggregation schemes, heuristics for improved upper bounds, and surrogate constraints. Our approach provides the ability to solve large size instances within reasonable solution times and very small optimality gaps. We also examine the effects of changes in the problem parameters on the performance of solution algorithms. Furthermore, in our computational experiments, we provide an analysis of the conditions for which relay network presents most benefits as well as incorporation of direct shipments within relay network operations.
Randomized Local Search for Real-Life Inventory Routing
Authors: Benoist Thierry , Gardi Frédéric , Jeanjean Antoine , Estellon Bertrand
Published: March 2011

In this paper, a new practical solution approach based on randomized local search is presented for tackling a real-life inventory routing problem. Inventory routing refers to the optimization of transportation costs for the replenishment of customers' inventories: based on consumption forecasts, the vendor organizes delivery routes. Our model takes into account pickups, time windows, drivers' safety regulations, orders, and many other real-life constraints. This generalization of the vehicle-routing problem was often handled in two stages in the past: inventory first, routing second. On the contrary, a characteristic of our local search approach is the absence of decomposition, made possible by a fast volume assignment algorithm. Moreover, thanks to a large variety of randomized neighborhoods, a simple first-improvement descent is used instead of tuned, complex metaheuristics. The problem being solved every day with a rolling horizon, the short-term objective needs to be carefully designed to ensure long-term savings. To achieve this goal, we propose a new surrogate objective function for the short-term model, based on long-term lower bounds. An extensive computational study shows that our solution is effective, efficient, and robust, providing long-term savings exceeding 20% on average, compared to solutions built by expert planners or even a classical urgency-based constructive algorithm. Confirming the promised gains in operations, the resulting decision support system is progressively deployed worldwide.
Robust Airline Scheduling Under Block-Time Uncertainty
Authors: Sohoni Milind , Lee Yu-Ching , Klabjan Diego
Published: March 2011

Airline schedule development continues to remain one of the most challenging planning activities for any airline. An airline schedule comprises a list of flights and specifies the origin, destination, scheduled departure, and arrival time of each flight in the airline's network. A critical component of the schedule development activity is the choice of flight block-times, which depend on several factors. Many airlines decide schedule block-times based on fixed percentiles of block-time distributions built from historical data, however, such techniques have not resulted in significantly improved on-time performance (OTP) of the schedule during operations. Thus, from a passenger's perspective, the service-level guarantee of an airline's network continues to be low. We first define two service-level metrics for an airline schedule. The first one is similar to the OTP measure of the U.S. Department of Transportation and we define it as the flight service level. The second metric, called the network service level, is geared toward completion of passenger itineraries. We then develop a stochastic integer programming formulation that optimally perturbs a given schedule to maximize expected profit, while ensuring the two service levels. We also develop a variant of this model that maximizes service levels, while achieving desired network profitability. To solve these models, we develop an efficient algorithm that guarantees optimality. Through extensive computational experiments, using real-world data, we demonstrate that our models and algorithms are efficient and achieve the desired trade-off between service level and profitability.
Routing Trains Through Railway Junctions: A New Set-Packing Approach
Authors: Lusby Richard , Larsen Jesper , Ryan David , Ehrgott Matthias
Published: March 2011

The problem of routing trains through railway junctions is an integral part of railway operations. Large junctions are highly interconnected networks of track where multiple railway lines merge, intersect, and split. The number of possible routings makes this a very complicated problem. We show how the problem can be formulated as a set-packing model with a resource-based constraint system. We prove that this formulation is tighter than the conventional node-packing model, and develop a branch-and-price algorithm that exploits the structure of the set-packing model. A discussion of the variable generation phase, as well as a pricing routine in which these variables are represented by tree structures, is also described. Computational experiments on 25 random timetables show this to be an efficient approach.
Enhanced Branch and Price and Cut for Vehicle Routing with Split Deliveries and Time Windows
Authors: Archetti C. , Bouchard M. , Desaulniers G.
Published: March 2011

In this paper, we study the split delivery vehicle routing problem with time windows (SDVRPTW) that is a variant of the well-known vehicle routing problem with time windows (VRPTW), where each customer can be served by more than one vehicle. We propose enhancement procedures for the exact branch-and-price-and-cut algorithm that was recently developed for the SDVRPTW. In particular, we introduce a tabu search algorithm to solve the column-generation subproblem, extensions of several classes of valid inequalities, and a new separation algorithm for the k-path inequalities. Computational results show the effectiveness of the proposed enhancements.
Luminescent acetylthiol derivative tripodal osmium(II) and iridium(III) complexes: Spectroscopy in solution and on surfaces
Authors: Ramachandra Srinidhi , Polo Federico , Edafe Fabio , Schuermann Klaus C. , Nijhuis Christian A. , Belser Peter , Reus William F. , Whitesides George M. , De Cola Luisa
Published: March 2011

Luminescent Os(II) and Ir(III) complexes containing a tripodal-type structure terminalized with three thiol derivatives are described. The tripod is introduced through derivatization, with a rigid spacer, of a phenanthroline ligand coordinated to the metal ion, and the entire structure possesses axial geometry. The geometry of the complexes combined with the three anchoring sites, the thiol groups, allows the complexes to adopt an almost perpendicular arrangement to the surfaces and the formation of a well-packed monolayer on Au substrates. The photophysical and electrochemical behavior of the complexes is studied in solution and on surfaces. Furthermore, a self-assembled monolayer (SAM) of Os(II) complexes on an ultraflat Au surface is used to fabricate a metal–molecule–metal junction with Au and In Ga eutectic as electrodes. The Os(II) SAM in the tunneling junction exhibits rectification behavior which is opposite in direction to that which we have previously shown for Ru(II) SAMs.
Experimental investigation of stress wave propagation in standing trees
Authors: Zhang Houjiang , Wang Xiping , Su Juan
Published: March 2011

The objective of this study was to investigate how a stress wave travels in a standing tree as it is introduced into the tree trunk through a mechanical impact. A series of stress wave time-of-flight (TOF) data were obtained from three freshly-cut red pine (Pinus resinosa Ait.) logs by means of a two-probe stress wave timer. Two-dimensional (2D) and three-dimensional (3D) stress wave contour maps were constructed based on the experimental data using a commercial software. These stress wave contour maps represent the wave fronts in a time sequence, illustrating the flow of stress wave energy within a log. The analysis of TOF data and wave fronts indicates that stress wave propagation in standing trees is affected by tree diameter, travel distance, and internal wood conditions (wood properties and structural defects). When a stress wave is introduced into a tree trunk from a point source, it initially propagates in the impact direction as a 3D wave. Then the flow of the stress wave energy gradually changes towards the longitudinal directions. As the diameter-to-distance ratio reaches 0.1 or below, the wave begins to travel as a quasi 1D wave.
Shake it, Baby, Shake it: Consumption and the New Gender Relation in Hip-Hop
Authors: Hunter Margaret
Published: March 2011

Hip-hop is a popular music genre that has generated a multi-billion dollar industry. Although its gender and race relations have historically been problematic, they have recently transformed in particular ways. This study examines the forty-one best-selling rap videos of 2007–2008. Through a qualitative content analysis of videos and lyrics several themes emerged. Hip-hop's focus on conspicuous consumption, buttressed by the success of entrepreneurial rap moguls, has merged with strip club culture to create a new gender relation based on sexual transaction. The “rap lifestyle,” marketed to consumers through multiple media outlets, focuses on the consumption of designer clothes, jewelry, cars, and liquor, often sold by the rap moguls' companies. Rap music videos advertise these products, as well as the consumption of women of color's sexual performances. The new hip-hop gender relation has also transformed the politics of dancing to fit the strip club themes of consumption and sexual transaction.
Marks of Possession: Methods for an Impossible Subject
Authors: Sánchez-Eppler Karen
Published: March 2011

In her 1892 study of children's literature, the child and his book, louise frances field complains, “the subject of this volume is one which, from its nature, presents many difficulties as regards material. It is the fate of children's books to be destroyed by children themselves” (v). Of course, the difficulties of children's literature are not only material. Jacqueline Rose's insistence on the “impossibility of children's fiction” has had the salutary effect of keeping scholars warily attuned to how adult desires—from sex to money to politics—structure the genre. Despite the claim of possession housed in that apostrophe, most scholars of children's literature acknowledge that these books don't really belong to children at all (Hunt). My intention in this essay is to use one of these impossibilities to circumvent the other. I am interested in children's own relation to their reading; I strive to understand not just the books adults produced for children—that is, what adults thought about childhood and wanted to say to children—but also what children actually did with these texts, how they took possession of them. I hope to demonstrate that the penchant for destroying books that Field deplores can provide insight into the literary history of childhood. For this brief essay, I take as my archive the book-destroying habits of the children of one affluent, highly literary family in post–Civil War New England: the niece and nephews of the poet Emily Dickinson—Edward (“Ned”), born in 1861; Martha (“Mattie”), born in 1866; and Thomas Gilbert (“Gib”), born in 1875.
Children's Books, Dolls, and the Performance of Race; or, The Possibility of Children's Literature
Authors: Bernstein Robin
Published: March 2011

In about 1855, three decades before frances hodgson burnett wrote her first best-selling children's book,little lord fauntleroy, she was a child—Frances Eliza Hodgson—and she read Harriet Beecher Stowe'sUncle Tom's Cabin.She found Stowe's novel, like all the stories she encountered, to be “unsatisfactory, filling her with vague, restless craving for greater completeness of form” (Burnett 44). The form the girl craved—that is, the material she believed she needed to complete the narrative—was a black doll. When Burnett obtained the doll, she named it Topsy and used it to “act” out the parts of the novel she found most “thrilling” (53). Casting a white doll she already owned as Little Eva, she played out ever-repeating scenes of Eva laying hands on Topsy, awakening the hardened slave girl to Christian love. Burnett also kept the Eva doll “actively employed slowly fading away and dying,” and in these scenes she took on the role of Uncle Tom (57). At other times, Burnett performed the scene of Eva's death, casting the white doll as Eva and herself as “all the weeping slaves at once” (58). And at least once she designated the doll Uncle Tom and cast herself as Simon Legree. For this scenario, the girl bound the doll to a candelabra stand. “[F]urious with insensate rage,” she whipped her doll (fig. 1). Throughout the whipping, the doll maintained a “cheerfully hideous” grin, which suggested to the girl that Uncle Tom was “enjoying the situation” of being “brutally lashed” (56, 55).
Queer Theory's Child and Children's Literature Studies
Authors: Kidd Kenneth
Published: March 2011

In 2002 Karín Lesnik-Oberstein and Stephen Thomson published an essay entitled “what is queer theory doing with the child?,” addressing work in the 1990s by Michael Moon and the late, great Eve Kosofsky Sedgwick on the “protogay” child. Something inappropriate, even scandalous, was their answer, as one might surmise from the accusatory shape of the question. In their reading, Moon and Sedgwick essentialize rather than interrogate the protogay child, such that said child becomes“an anti-theoreticalmoment, resistant to analysis, itself the figure deployedasresistance” (36). For Lesnik-Oberstein and Thomson, queer theory is insufficiently alert to the lessons of poststructuralist theory and especially to the ongoing interrogation of “child” and “childhood.” Lesnik-Oberstein and Thomson specialize in childhood studies, and Lesnik-Oberstein is a well-known scholar of children's literature. Her 1994Children's Literature: Criticism and the Fictional Childextends and takes inspiration from Jacqueline Rose'sThe Case of Peter Pan; or, The Impossibility of Children's Fiction(1984), which ushered into children's literature studies a powerful and lasting skepticism about “childhood” and “children's literature.”
Dr. Seuss in Ted Geisel's Never-Never Land
Authors: Pease Donald E.
Published: March 2011

Like many other subscribers to PMLA and most of the students enrolled in my literature classes, i first learned that reading could be a pleasure when I discovered Dr. Seuss's children's books. The Cat in the Hat implanted the desire to learn how to read in an entire generation of baby boomers. Dr. Seuss (the literary identity of Theodor Seuss Geisel) helped millions of children learn to read, and his books planted the seeds for a more caring, open, and creative culture.
Thine and Mine: The Spanish “Golden Age” and Early Modern Studies
Authors: Greer Margaret R.
Published: March 2011

Don Quixote, having shared the goatherds' rustic meal on his second sally, takes up a handful of acorns and launches into his lecture on the Golden Age: “Dichosa edad y siglos dichosos aquellos a quien los antiguos pusieron nombre de dorados, y no porque en ellos el oro, que en esta nuestra edad de hierro tanto se estima, se alcanzase en aquella venturosa sin fatiga alguna, sino porque entonces los que en ella vivían ignoraban estas dos palabras de tuyo y mío” ‘Blessed the time, and blessed the centuries, called by the ancients the Golden Age—and not because, then, the gold which we in our age of iron so value came to men's hands without effort, but because those who walked the earth in that time knew nothing of those two words, thine and mine.’ Bewildering as his harangue was for the listening goatherds, Don Quixote's introduction invites consideration of the location, ownership, and definition of the Spanish “Golden Age.” These aspects illuminate the challenge the period presents to early modern studies and vice versa.