Algorithms for two-dimensional cutting stock and strip packing problems using dynamic programming and column generation

We investigate several two-dimensional guillotine cutting stock problems and their variants in which orthogonal rotations are allowed. We first present two dynamic programming based algorithms for the Rectangular Knapsack (RK) problem and its variants in which the patterns must be staged. The first algorithm solves the recurrence formula proposed by Beasley; the second algorithm - for staged patterns - also uses a recurrence formula. We show that if the items are not so small compared to the dimensions of the bin, then these algorithms require polynomial time. Using these algorithms we solved all instances of the RK problem found at the OR-LIBRARY, including one for which no optimal solution was known. We also consider the Two-dimensional Cutting Stock problem. We present a column generation based algorithm for this problem that uses the first algorithm above mentioned to generate the columns. We propose two strategies to tackle the residual instances. We also investigate a variant of this problem where the bins have different sizes. At last, we study the Two-dimensional Strip Packing problem. We also present a column generation based algorithm for this problem that uses the second algorithm above mentioned where staged patterns are imposed. In this case we solve instances for two-, three- and four-staged patterns. We report on some computational experiments with the various algorithms we propose in this paper. The results indicate that these algorithms seem to be suitable for solving real-world instances. We give a detailed description (a pseudo-code) of all the algorithms presented here, so that the reader may easily implement these algorithms. (c) 2007 Elsevier B.V. All rights reserved.

False-positive results of a rapid K39-based strip test and Chagas disease

Background: The definitive diagnosis of visceral. leishmaniasis (VL) requires invasive procedures with demonstration of amastigotes in tissue or promastigotes in culture. Unfortunately, these approaches require laboratory materials not available in poor countries where the disease is endemic. The correct diagnosis of VL is important, and made more difficult by the fact that several common tropical diseases such as malaria, disseminated tuberculosis, and enteric fever share the same clinical presentation. Serological tests have been developed to replace parasitological diagnosis in the field. A commercially available K39-based strip test for VL has been developed for this purpose. The endemic area of leishmaniasis in Brazil overlaps the endemic area of Chagas disease, a disease that can cause false-positive serological test results. The aim of this study was to evaluate the incidence of false-positive exams using a rapid test for VL in patients with Chagas disease. Methods: A rapid test based on the recombinant K39 antigen of Leishmania was used in: (1) 30 patients with confirmed Chagas disease, (2) 30 patients with a serological diagnosis of Chagas disease by ELISA, indirect immunofluorescence, indirect hemagglutination, and chemiluminescence, (3) 30 healthy patients from a non-endemic area as the control group, (4) 30 patients with confirmed VL, and (5) 20 patients with proved cutaneous leishmaniasis. Results: The sensitivity and specificity of the rapid strip test were 100% when compared with healthy volunteers and those with confirmed Chagas disease. One false-positive result occurred in the group with Chagas disease diagnosed by serological tests (specificity of 96%). Conclusion: The rapid test based on recombinant K39 is a useful diagnostic assay, and a false-positive result rarely occurs in patients with a serological diagnosis of Chagas disease. (C) 2008 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Prevalence of Human Papillomaviruses in Urine Samples of Male Patients Infected With HIV-1 in Sao Paulo, Brazil

Human papillomavirus is a DNA virus that includes 118 genotypes. HPV16 is responsible for 80% of cervical cancer in women. Men are important reservoirs and major transmitters of HPV to their partners. The aim of this study was to detect HPV DNA and to determine the prevalence of HPV types 6, 11, 16, and 18 in urine samples of men infected with HIV-1. This study included 223 patients infected with HIV-1 from the Center of Reference on HIV/AIDS (CRT-SP) and an outpatient clinic of HIV. Urine samples were collected and after DNA extraction real-time PCR was performed for detection of HPV DNA. Positive samples were then tested by conventional PCR using type-specific primers for the four HPV types. A total of 223 men infected with HIV-1 were tested, 81% of whom were on HAART. Four (5.8%) were positive for HPV6, 18 (26.1%) were positive for HPV11, 22 (31.9%) were positive for HPV16 and five (7.2%) were positive for HPV18 by conventional PCR. Twenty (29%) patients had other HPV types and five patients (1.5%) had multiple types. The mean T CD4+cells count was 517 and 441 cells/mm(3) (P=0.30), in HPV negative and positive men, respectively. The HIV viral load was higher in the HPV negative group than for in the men with HPV (P=0.0002). A 30.9% prevalence of HPV was found in asymptomatic urine samples of men infected with HIV-1. This study suggests that urine may be a useful specimen for HPV screening. J. Med. Virol 81:2007-2011, 2009. (C) 2009 Wiley-Liss, Inc.

Recovery of DNA for the detection and genotyping of human papillomavirus from clinical cervical specimens stored for up to 2 years in a universal collection medium with denaturing reagent

The recovery and stability of DNA for the detection and genotyping of HPV in UCM-containing specimens, after exposure to denaturing reagents and stored for up to 2 years were evaluated. Samples were collected from 60 women who had cervical cytology specimens harboring cervical intraepithelial neoplasia (CIN) 2 or 3. All samples were stored in UCM and had been frozen at -20 degrees C following the addition of the denaturing reagent (sodium hydroxide) and the removal of the aliquot required for Hybrid Capture 2 testing for the identification of HPV DNA. The samples had been stored for 6, 12 and 24 months (20 samples for each storage time). HPV DNA extraction was performed according to a protocol designed specifically and the presence and quality of DNA was confirmed by human P-globin detection using the consensus primers G73 and G74. HPV DNA was amplified using the consensus primers PGMY09 and PGMY11, and reverse line-blot hybridization was used to detect type-specific amplicons for 37 HPV types. The DNA extracted from the denatured specimen was recovered in 57/60 (95%) of the samples. HPV DNA was detected in 56/57 (98%) of the recovered samples. Twenty-six of the 56 samples recovered (48%) were genotyped successfully. (c) 2007 Elsevier B.V. All rights reserved.

Facile Synthesis of Koser`s Reagent and Derivatives from Iodine or Aryl Iodides

The first one-pot synthesis of neutral and electron-rich [hydroxy(tosyloxy)iodo]arenes (HTIBs) from iodine and arenes is presented, thereby avoiding the need for expensive iodine(III) precursors. A large set of including a polyfluorinated analogue, can be obtained from the corresponding aryl iodide under the same conditions. The reaction proceeds under mild conditions, without excess reagents, and is fast and high-yielding. Together, the two presented routes give access to a wide range of HTIBs, which are useful reagents in a variety of synthetic transformations.

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

in this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ`s (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its` metabolites was further confirmed by MS/MS experiments.

Detection of Paraquat in Oral Fluid, Plasma, and Urine by Capillary Electrophoresis for Diagnosis of Acute Poisoning

FAPESP

Preparation of alpha,beta-Unsaturated Diazoketones Employing a Horner-Wadsworth-Emmons Reagent

A new method for the preparation of alpha,beta-unsaturated diazoketones from aldehydes and a Horner-Wadsworth- Emmons reagent is reported. The method was applied to the short synthesis of two substituted pyrrolidines.

Determination of epinephrine in urine using multi-walled carbon nanotube modified with cobalt phthalocyanine in a paraffin composite electrode

This paper describes the development, electrochemical characterization and utilization of a cobalt phthalocyanine (CoPc), modified multi-walled carbon nanotube (MWCNT), and paraffin composite electrode for the quantitative determination of epinephrine (EP) in human urine samples. The electrochemical profile of the proposed composite electrode was analyzed by differential pulse voltammetry (DPV) that showed a shift of the oxidation peak potential of EP at 175 mV to less positive value, compared with a paraffin/graphite composite electrode without CoPc. DPV experiments in PBS at pH 6.0 were performed to determine EP without any previous step of extraction, clean-up, and derivatization, in the range from 1.33 to 5.50 mu mol L(-1), with a detection limit of 15.6 nmol L(-1) (2.86) of EP in electrolyte prepared with purified water. The lifetime of the proposed sensors was at least over 1000 determinations with 1.7 and 3.1 repeatability and reproducibility relative standard deviations, respectively. Human urine samples without any purification step were successfully analyzed under the standard addition method using paraffin/MWCNT/CoPc composite electrode. (C) 2010 Elsevier B.V. All rights reserved.