Carlos Pacheco

New Jersey Institute of Technology, Chemistry & Enviornmental Science, Faculty Member

Penn State University, Chemistry, Faculty Member

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Ph.D. in Chemistry with several years of industrial experience and 10 years of academic experience as Manager of the NMR Facilities at Princeton University/Chemistry and University of Connecticut/Chemistry, Pharmacy and as NMR Spectroscopist at Penn State University/Chemistry. Core Competencies• Strong background in solution and solid-state NMR. • Broad knowledge and hands-on maintenance experience of Bruker and Agilent (Varian) NMR instrumentation. • Hands-on and working knowledge of other spectroscopies: FTIR, UV/Vis/NIR, Raman, EPR. Other techniques: TGA, DSC, GC-IR, and LC-MS.• Wide experience in small molecule structure elucidation and biological NMR.• Lead research projects in developing and validating NMR methodologies.
Phone: 6092405957
Address: Pennsylvania State University
Department of Chemistry
104 Chemistry Building
Room 14
State College PA 16802

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Papers by Carlos Pacheco

CHEM 222-001: Analytical Chemistry

Although endocranial abnormal blood vessel impressions (ABVIs) and periosteal appositions (PAs) h... more Although endocranial abnormal blood vessel impressions (ABVIs) and periosteal appositions (PAs) have been considered as paleopathological diagnostic criteria for tuberculous meningitis (TBM) based on findings of previous studies, they are not pathognomonic for tuberculosis (TB). Therefore, their utilization in the paleopathological practice can be questioned, especially in consideration that most of the previous studies were not performed on identified skeletal collections but on osteoarchaeological material and did not include statistical data analysis. To fill the aforementioned research gap, for the first time, a macroscopic investigation was conducted on identified pre-antibiotic era skeletons from the Terry Collection. A sample set of 234 individuals who died of TB (TB group) and 193 individuals who died of non-tuberculous causes (NTB group) were examined. The frequency of ABVIs and PAs, as well as other probable TB-related lesions was recorded. To determine the significance of difference (if any) in the frequencies of ABVIs and PAs between the two groups, χ 2 testing of our data was performed. We found that ABVIs, PAs, and their co-occurrence with each other and with other probable TB-related lesions were more common in the TB group than in the NTB group. In addition, the χ 2 comparative frequencies of ABVIs and PAs revealed a statistically significant difference between individuals who died of TB and individuals who died of NTB causes. Our findings strengthen those of previous studies that ABVIs and PAs are not specific to TBM but can be of tuberculous origin. Therefore, they do have a diagnostic value in the identification of TB in human osteoarchaeological material, especially when they simultaneously occur with other probable TB-related lesions. Their prudent utilization provides paleopathologists with a stronger basis for diagnosing TB and consequently, a more sensitive means of assessing TB frequency in past human populations.

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T3P-promoted synthesis of a series of novel 2-aryl-3-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones

Tetrahedron Letters, 2020

Abstract A series of twelve novel 2-aryl-3-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones was pr... more Abstract A series of twelve novel 2-aryl-3-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of C-aryl-N-phenyl imines with 3-mercaptopropionic acid. The reaction can also be run as a 3-component reaction, forming the imine in situ. The reactions were operationally simple, rapid and gave yields as high as 75%. This provides ready access to C-aryl-N-phenyl compounds in this family, which have been generally difficult to prepare.

Comparison of thermally actuated retro-diels-alder release groups for nanoparticle based nucleic acid delivery

Journal of colloid and interface science, Jan 24, 2018

The present study explores alternate pericyclic chemistries for tethering amine-terminal biomolec... more The present study explores alternate pericyclic chemistries for tethering amine-terminal biomolecules onto silver nanoparticles. Employing the versatile tool of the retro-Diels-Alder (rDA) reaction, three thermally-labile cycloadducts are constructed that cleave at variable temperature ranges. While the reaction between furan and maleimide has widely been reported, the current study also evaluates the reverse reaction kinetics between thiophene-maleimide, and pyrrole-maleimide cycloadducts. Density Functional Theorem (DFT) calculations used to model and plan the experiments, predict energy barriers for the thiophene-maleimide reverse reaction to be greatest, and the pyrrole-maleimide barriers the lowest. Based on the computational analyses, it is projected that the cycloreversion rate would occur slowest with the thiophene, followed by furan, and finally pyrrole would yield the promptest release. These thermally-responsive linkers, characterized by Electrospray Ionization Mass Spect...

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Segmented molecular design of self-healing proteinaceous materials

Scientific Reports, 2015

Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and ... more Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and-assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine-and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.

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• Pacheco, C., Menezes, S.M., Morgado, E., Chapter 6 (pp.125-165), “NMR Studies of Colloidal Oxides”, in “Surfaces of Nanoparticles and Porous Materials” James A. Schwarz, Cristian I. Contescu, Editors, Published by CRC Press, 1999, ISBN 0824719336, 787 pages

Two New Window Functions for Long Acquisition Times

Journal of Magnetic Resonance, Series A, 1996

Ion-polymer interaction analysis: an inversion of NMR spin echo experimental data

Brazilian Journal of Physics, 2010

A methodology for ion-polymer interaction estimation is discussed in the present work. This metho... more A methodology for ion-polymer interaction estimation is discussed in the present work. This method is based on the inversion of experimental spin echo NMR data using Hopfield neural network to retrieve transverse relaxation time distributions. The adopted model systems consist of aqueous solutions of poly (ethylene oxide), molar mass 1500, 4000 and 35000 g mol −1 and sodium nitroprusside (NP) at different concentrations. Dipolar interaction is investigated in this work through the reduction in the transverse relaxation time and increase in the area under the distribution curves of the PEO protons which presented a linear correlation with the NP concentration. Neural network results were compared with the Simplex optimization procedure and experimental NMR values. The proposed methodology is robust, stable, non restrictive in relation to the system and more efficient to handle experimental data.

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Diffusion of Protein in Polymer Solutions: A Comparison between Neutron Spin-Echo Spectroscopy and NMR Measurements Methods

T3P-Promoted Synthesis of a Series of 2-Aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones and Their Activity against the Kinetoplastid Parasite Trypanosoma brucei

Molecules

A series of fourteen 2-aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones was prepared... more A series of fourteen 2-aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-phenyl-C-aryl imines with thionicotinic acid, two difficult substrates. The reactions were operationally simple, did not require specialized equipment or anhydrous solvents, could be performed as either two or three component reactions, and gave moderate–good yields as high as 63%. This provides ready access to N-phenyl compounds in this family, which have been generally difficult to prepare. As part of the study, the first crystal structure of neutral thionicotinic acid is also reported, and showed the molecule to be in the form of the thione tautomer. Additionally, the synthesized compounds were tested against T. brucei, the causative agent of Human African Sleeping Sickness. Screening at 50 µM concentration showed that five of the compounds strongly inhibited growth and killed parasites.

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Inverting weak random operators

Random Operators and Stochastic Equations

We analyze two weak random operators, initially motivated from processes in random environment. A... more We analyze two weak random operators, initially motivated from processes in random environment. At first glance, these operators are ill-defined, but using bilinear forms, one can deal with them in a rigorous way. This point of view can be found, for instance, in [A. V. Skorohod, Random Linear Operators, Math. Appl. (Sov. Ser.), D. Reidel Publishing, Dordrecht, 1984], and it remarkably helps to carry out specific calculations. In this paper, we find explicitly the inverse of such weak operators by providing the closed forms of the so-called Green kernel. We show how this approach helps to analyze the spectra of the operators. In addition, we provide the existence of strong operators associated to our bilinear forms. Important tools that we use are the Sturm–Liouville theory and the stochastic calculus.

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Non-Peptide Polymeric Silicatein a Mimic for Neutral pH Catalysis in the Formation of Silica

Macromolecules, 2007

We have synthesized a catalytically active polymer inspired by the naturally occurring protein si... more We have synthesized a catalytically active polymer inspired by the naturally occurring protein silicatein R and have shown it to catalyze the formation of silica from tetraethoxysilane under near-neutral pH and ambient temperatures. We based the composition of the polymer on the functionalities found in silicatein R, specifically those essential components of the catalytically active site for the hydrolysis of silicon alkoxides. Our bioinspired polymer is a block copolymer of poly(2-vinylpyridine-b-1,2-butadiene), functionalized by the addition of hydroxyl groups via hydroboration chemistry. The catalytic action of our polymer on tetraethoxysilane at neutral pH and ambient temperature conditions has been confirmed using a modified molybdic acid assay method, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The structure of the resulting gel is investigated by scanning electron microscopy and solid-state nuclear magnetic resonance. The microscopic features of the material formed resemble that of gels formed by the acid-catalyzed hydrolysis of tetraethoxysilane.

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Spectroscopic Investigation of the Mechanisms Responsible for the Superior Stability of Hybrid Class 1/Class 2 CO2 Sorbents: A New Class 4 Category

ACS applied materials & interfaces, May 4, 2016

Hybrid Class 1/Class 2 supported amine CO2 sorbents demonstrate superior performance under practi... more Hybrid Class 1/Class 2 supported amine CO2 sorbents demonstrate superior performance under practical steam conditions, yet their amine immobilization and stabilization mechanisms are unclear. Uncovering the interactions responsible for the sorbents' robust features is critical for further improvements and can facilitate practical applications. We employ solid state (29)Si CPMAS and 2-D FSLG (1)H-(13)C CP HETCOR NMR spectroscopies to probe the overall molecular interactions of aminosilane/silica, polyamine [poly(ethylenimine), PEI]/silica, and hybrid aminosilane/PEI/silica sorbents. A unique, sequential impregnation sorbent preparation method is executed in a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) set-up to decouple amine binding mechanisms at the amine-silica interface from those within bulk amine layers. These mechanisms are correlated with each sorbents' resistance to accelerated liquid H2O and TGA steam treatments (H2O stability), and to oxid...

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Analysis of benzoquinolines and acridines in a Brazilian diesel oil by particle beam LC/MS and HPLC/UV

Journal of Liquid …, 1995

Page 1. JOURNAL OF LIQUID CHROMATOGWHY, 18(5), 903-916 (1995) ANALYSIS OF BENZOQUINOLINES AND ACR... more

Non-Peptide Polymeric Silicatein α Mimic for Neutral pH Catalysis in the Formation of Silica

by Marcus Giotto and Carlos Pacheco

Macromolecules, 2007

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Ph.D. Dissertation - “The Use of Inverse Detected NMR for the Analyses of Diesel Oil Extracts” - University of Rhode Island, Kingston, Rhode Island, USA, 1996, supervision: Prof. Daniel D. Traficante

Proton Detected Experiments: 2D Heteronuclear Chemical Shift at Natural Abundance 15N Level of Diesel Oils Extracts

• Pacheco, C. R.N., Schuster, I. “1H/19F Double Resonance Experiments at 400-MHz: Hardware Evaluation and nJFF Determination (n = 5, 6)” (P) Proceedings of the 7th Brazilian Journey of Magnetic Resonance, July 27-30, 2004

Transverse and Longitudinal Relaxation Time Distribution from Spin echo Experiments Using Hopfield Neural Network

The Hopfield neural network is proposed in this work to invert transverse and longitudinal relaxa... more The Hopfield neural network is proposed in this work to invert transverse and longitudinal relaxation time decay curve from spin-echo experiments. Simulated and experimental data were used to test the performance of this approach. The inverse Laplace transform, commonly used to address this problem, is used as the initial guess for the network. The probability density function can be used

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2D HETCOR Studies of the Miscibility of EVA/PVAc Blends

• Srivastava, Rajendra Mohan; Da Conceicao Pereira, Maria; Hallwass, Fernando; Pacheco, Carlos R. N. “Synthesis and Molecular Orbital Calculations of N, N-Diethyl-3- [3-(Aryl)-1,2,4- Oxadiazol-5-Yl] Propionamides”, Heterocycles (1999), 51(12), 2961-2967

by Carlos Pacheco and Fernando Hallwass

Heterocycles

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Carlos Pacheco

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