Publications by authors named "Urdaneta N"

Boronate esters are a class of compounds containing a boron atom bonded to two oxygen atoms in an ester group, often being used as precursors in the synthesis of other materials. The characterization of the structure and properties of esters is usually carried out by UV-visible, infrared, and nuclear magnetic resonance (NMR) spectroscopic techniques. With the aim to better understand our experimental data, in this article, the density functional theory (DFT) is used to analyze the UV-visible and infrared spectra, as well as the isotropic shielding and chemical shifts of the hydrogen atoms H, carbon C and boron B in the compound 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde.

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The use of computational methods that allow us to perform characterization on new compounds is not a novelty; nevertheless, the degree of complexity of the structures makes their study more challenging since new techniques and methods are required to adjust to the new structural model. The case of nuclear magnetic resonance characterization of boronate esters is fascinating because of its widespread use in materials science. In this paper, we use density functional theory to characterize the structure of the compound 1-[5-(4,5-Dimethyl-1,3,2-dioxaborolan-2-yl)thiophen-2-yl]ethanonea by means of nuclear magnetic resonance.

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Compelling pieces of evidence derived from both clinical and experimental research has demonstrated the crucial contribution of diabetes mellitus (DM) as a risk factor associated with increased cancer incidence and mortality in many human neoplasms, including gastric cancer (GC). DM is considered a systemic inflammatory disease and therefore, this inflammatory status may have profound effects on the tumor microenvironment (TME), particularly by driving many molecular mechanisms to generate a more aggressive TME. DM is an active driver in the modification of the behavior of many cell components of the TME as well as altering the mechanical properties of the extracellular matrix (ECM), leading to an increased ECM stiffening.

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The methanol extract form the leaves of Phytolacca icosandra L., afforded the unprecedented artificial triterpenoid fatty acid ester 1 derived from the new natural triterpenoid phytolaccagenic acid 3-O-myristate (1a), along with the three known triterpenoids serjanic, acinosolic and phytolaccagenic acid (2 - 4). Their structures were stablished by HR-EI-MS, 1D and 2D NMR techniques.

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Orange rectangular blocks suitable for X-ray diffraction analysis were obtained for the previously reported [Ahmad & Bano (2011). Int. J.

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In both title compounds, C(10)H(13)BO(3)S, (I), and C(13)H(17)BO(3), (II), the molecules adopt nearly planar conformations. The crystal packing of (I) consists of a supramolecular two-dimensional network with a herringbone-like topology formed by self assembly of centrosymmetric pairs of molecules linked via dipole-dipole interactions. The crystal structure of (II) consists of a supramolecular two-dimensional network built up from centrosymmetric pairs of molecules via π-π interactions.

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Introduction: It has been demonstrated that scintigraphy with somatostatin analogues is useful for the diagnosis, staging and follow up of patients with neuroendocrine tumors from the gastrointestinal tract (NET-GIT). Some studies suggest that the use of 99mTc-Hydrazinonicotinyl-Tyr3-octreotide (99mTc-HYNIC-TOC) yields similar diagnostic results than the use of 111In-DTPA-octreotide.

Objective: To determine the clinical value of scintigraphy using 99mTc-HYNIC-TOC for the detection of primary and secondary lesions in patients with NET-GIT.

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A chloroform extract from roots of Craniolaria annua provided six new C-11 unsubstituted abietanes, 14-hydroxy-6,12-dione-7,9(11),13-abietatriene (1), 14-hydroxy-12-oxo-7,9(11),13-abietatriene (2), 6,12,14-trihydroxyabieta-5,8,11,13-tetraen-7-one (3), ar-abietatriene-12-ol-6,7-dione-14,16-oxide (4), ar-abietatriene-12,16-diol-14,16-oxide (5) and ar-abietatriene-12-ol-7-one-14,16-oxide (6), and two known compounds, ferruginol and stigmasterol. The structures of both the new and known compounds were established by spectroscopic methods. Abietane 1 gave 14-hydroxy-6-oxoferruginol (1A) upon treatment with NaBH4.

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The asymmetric unit of the title compound, C(17)H(16)ClNO, contains two crystallographically independent mol-ecules. These mol-ecules are connected in an alternating fashion through N-H⋯O and C-H⋯O hydrogen bonds, generating one-dimensional chains of graph sets R(2) (1)(6) and C(4) along the a axis.

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Six functionalized 1,3-dienes were synthesized using cross-coupling reactions, catalyzed by palladium complexes, between alkenylboronic acids and alpha-bromo-alpha,beta-unsaturated carbonylic compounds. Their cytotoxicity against epimastigotes of Trypanosoma cruzi and fibroblastic Vero cells was evaluated, using concentrations ranging from 100 microM to 2.5 mM in experiments with three incubation times (4, 8 and 16 h).

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Five candidate pheromone components were identified by analyzing pheromone gland extracts by gas chromatography (GC), coupled GC-electroantennographic detection (EAD), and coupled GC-mass spectrometry (MS) : (E)-11-hexadecenol(E11-16 : OH), (Z)-11-hexadecenol (Z11-16 : OH), (E)-11-hexadecenal, (E)-11-hexadecenyl acetate, and (Z)-3,(Z)-6,(Z)-9-tricosatriene (Z3,Z6,Z9-23 : Hy). In electroantennogram (EAG) recordings, synthetic E11-16 : OH elicited stronger antennal responses at low doses than other candidate pheromone components. Field tests demonstrated that synthetic E11-16 : OH as a trap bait was effective in attracting males, whereas addition of Z11-16 : OH inhibited the males' response.

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The purpose of this study was to determine the efficacy of mitomycin C as an adjunct to radiotherapy for the treatment of locally advanced cervix cancer. Patients with squamous-cell carcinoma of the cervix, stages IB2-IVA, were randomized to receive radiotherapy alone or radiotherapy with concomitant mitomycin C. An initial cohort of 160 patients, having a mean follow-up of 46 months, is analyzed.

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Attraction to host plants by adultRhynchophorus palmarum (L.) palm weevils was studied in the field and in the laboratory. Chemical analysis revealed the presence of ethanol and ethyl-acetate in stems of coco palms and in pineapple fruits and of pentane, hexanal, and isopentanol in coco stems.

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The role of intracavitary irradiation in the treatment of uterine cervix carcinoma is well established, and over the years a number of different systems for intracavitary irradiation have been developed. To compare the clinical efficacy of different systems and to develop guidelines for the design of applicators with new sources such as americium-241, we present a dosimetric comparison of three systems: (a) the Morris system, a modified Stockholm technique; (b) the Henschke system; and (c) the Fletcher system. Using a computerized planning system, dose distributions with different configurations of each system were calculated.

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Seven patients with olfactory neuroblastoma were treated, using the staging classification proposed by Kadish (stage A two patients, stage B one, stage C three, and local recurrence one patient). Treatment was not uniform. Radiation therapy was employed initially as the only treatment modality in three patients who had stage A, B, and C, respectively.

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To assess the diagnostic value of indices measured on a first-pass curve, we performed 72 radionuclide renal first-pass studies (RFP) in 21 patients during the early weeks following renal allograft transplantation. The diagnosis was based on standard clinical and biochemical data and on fine needle aspiration biopsy (FNAB) of the transplant. Aortic and renal first-pass curves were filtered using a true low-pass filter and five different indices of renal perfusion were computed, using formulae from the literature.

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A 64-year-old woman had a sphenoid sinus tumor and nasopharyngeal mass verified to be a nasopharyngeal chromophobe adenoma with no evidence of sellar enlargement or involvement. The possibility that this mass arose from ectopic hypophyseal tissue located in the pharynx is proposed.

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Forty-three cases of cancer of the nasopharynx treated at the Yale-New Haven Hospital in the last 15 years were analyzed. The clinical aspects of the disease, the technique of therapy and results of treatment are presented. The five-year cumulative survival in all the cases treated was 27%.

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Two brothers with breast cancer are presented. One died 8 years after diagnosis and the other is presently living at 1 year with metastatic disease. The courses of 28 other previously unreported male patients with carcinoma of the breast are reviewed, and the possibility of male breast carcinoma being metastatic disease from the prostate is discussed.

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