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• Analytical Chemistry and Spectroscopy  (243)
• Animals  (201)
• Computational Chemistry and Molecular Modeling  (45)
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• 1
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Nature Publishing Group (NPG)
Publication Date: 2012-06-16
Description: Autism spectrum disorder (ASD) is a group of conditions characterized by impaired social interaction and communication, and restricted and repetitive behaviours. ASD is a highly heritable disorder involving various genetic determinants. Shank2 (also known as ProSAP1) is a multi-domain scaffolding protein and signalling adaptor enriched at excitatory neuronal synapses, and mutations in the human SHANK2 gene have recently been associated with ASD and intellectual disability. Although ASD-associated genes are being increasingly identified and studied using various approaches, including mouse genetics, further efforts are required to delineate important causal mechanisms with the potential for therapeutic application. Here we show that Shank2-mutant (Shank2(-/-)) mice carrying a mutation identical to the ASD-associated microdeletion in the human SHANK2 gene exhibit ASD-like behaviours including reduced social interaction, reduced social communication by ultrasonic vocalizations, and repetitive jumping. These mice show a marked decrease in NMDA (N-methyl-D-aspartate) glutamate receptor (NMDAR) function. Direct stimulation of NMDARs with D-cycloserine, a partial agonist of NMDARs, normalizes NMDAR function and improves social interaction in Shank2(-/-) mice. Furthermore, treatment of Shank2(-/-) mice with a positive allosteric modulator of metabotropic glutamate receptor 5 (mGluR5), which enhances NMDAR function via mGluR5 activation, also normalizes NMDAR function and markedly enhances social interaction. These results suggest that reduced NMDAR function may contribute to the development of ASD-like phenotypes in Shank2(-/-) mice, and mGluR modulation of NMDARs offers a potential strategy to treat ASD.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Won, Hyejung -- Lee, Hye-Ryeon -- Gee, Heon Yung -- Mah, Won -- Kim, Jae-Ick -- Lee, Jiseok -- Ha, Seungmin -- Chung, Changuk -- Jung, Eun Suk -- Cho, Yi Sul -- Park, Sae-Geun -- Lee, Jung-Soo -- Lee, Kyungmin -- Kim, Daesoo -- Bae, Yong Chul -- Kaang, Bong-Kiun -- Lee, Min Goo -- Kim, Eunjoon -- England -- Nature. 2012 Jun 13;486(7402):261-5. doi: 10.1038/nature11208.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, KAIST, Daejeon 305-701, Korea.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22699620" target="_blank"〉PubMed〈/a〉
Keywords: Adaptor Proteins, Signal Transducing/*genetics ; Animals ; Antimetabolites/pharmacology ; *Autistic Disorder/genetics/metabolism ; Behavior, Animal/*drug effects/physiology ; Benzamides/*pharmacology ; Cycloserine/*pharmacology ; Disease Models, Animal ; Female ; Male ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins/*genetics ; Pyrazoles/*pharmacology ; Receptors, N-Methyl-D-Aspartate/*agonists/*metabolism
Print ISSN: 0028-0836
Electronic ISSN: 1476-4687
Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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• 2
Unknown
Nature Publishing Group (NPG)
Publication Date: 2016-01-19
Description: Many procedures in modern clinical medicine rely on the use of electronic implants in treating conditions that range from acute coronary events to traumatic injury. However, standard permanent electronic hardware acts as a nidus for infection: bacteria form biofilms along percutaneous wires, or seed haematogenously, with the potential to migrate within the body and to provoke immune-mediated pathological tissue reactions. The associated surgical retrieval procedures, meanwhile, subject patients to the distress associated with re-operation and expose them to additional complications. Here, we report materials, device architectures, integration strategies, and in vivo demonstrations in rats of implantable, multifunctional silicon sensors for the brain, for which all of the constituent materials naturally resorb via hydrolysis and/or metabolic action, eliminating the need for extraction. Continuous monitoring of intracranial pressure and temperature illustrates functionality essential to the treatment of traumatic brain injury; the measurement performance of our resorbable devices compares favourably with that of non-resorbable clinical standards. In our experiments, insulated percutaneous wires connect to an externally mounted, miniaturized wireless potentiostat for data transmission. In a separate set-up, we connect a sensor to an implanted (but only partially resorbable) data-communication system, proving the principle that there is no need for any percutaneous wiring. The devices can be adapted to sense fluid flow, motion, pH or thermal characteristics, in formats that are compatible with the body's abdomen and extremities, as well as the deep brain, suggesting that the sensors might meet many needs in clinical medicine.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kang, Seung-Kyun -- Murphy, Rory K J -- Hwang, Suk-Won -- Lee, Seung Min -- Harburg, Daniel V -- Krueger, Neil A -- Shin, Jiho -- Gamble, Paul -- Cheng, Huanyu -- Yu, Sooyoun -- Liu, Zhuangjian -- McCall, Jordan G -- Stephen, Manu -- Ying, Hanze -- Kim, Jeonghyun -- Park, Gayoung -- Webb, R Chad -- Lee, Chi Hwan -- Chung, Sangjin -- Wie, Dae Seung -- Gujar, Amit D -- Vemulapalli, Bharat -- Kim, Albert H -- Lee, Kyung-Mi -- Cheng, Jianjun -- Huang, Younggang -- Lee, Sang Hoon -- Braun, Paul V -- Ray, Wilson Z -- Rogers, John A -- F31MH101956/MH/NIMH NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2016 Feb 4;530(7588):71-6. doi: 10.1038/nature16492. Epub 2016 Jan 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Department of Neurological Surgery, Washington University School of Medicine, St Louis, Missouri 63110, USA. ; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea. ; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Department of Engineering Science and Mechanics, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. ; Institute of High Performance Computing, Singapore 138632, Singapore. ; Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA. ; Department of Biomicrosystem Technology, Korea University, Seoul 136-701, South Korea. ; Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-713, South Korea. ; Weldon School of Biomedical Engineering, School of Mechanical Engineering, The Center for Implantable Devices, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA. ; School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA. ; Department of Mechanical Engineering, Civil and Environmental Engineering, Materials Science and Engineering, and Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208, USA. ; Department of Biomedical Engineering, College of Health Science, Korea University, Seoul 136-703, South Korea. ; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26779949" target="_blank"〉PubMed〈/a〉
Keywords: *Absorbable Implants/adverse effects ; Administration, Cutaneous ; Animals ; Body Temperature ; Brain/*metabolism/surgery ; Electronics/*instrumentation ; Equipment Design ; Hydrolysis ; Male ; Monitoring, Physiologic/adverse effects/*instrumentation ; Organ Specificity ; Pressure ; *Prostheses and Implants/adverse effects ; Rats ; Rats, Inbred Lew ; *Silicon ; Telemetry/instrumentation ; Wireless Technology/instrumentation
Print ISSN: 0028-0836
Electronic ISSN: 1476-4687
Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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• 3
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0935-6304
Keywords: Capillary GC ; Enantiomer resolution ; Chiral stationary phase ; Derivated cyclodextrins ; Chemistry ; Analytical Chemistry and Spectroscopy
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology
Notes: Three new β-cyclodextrin derivatives, heptakis(6-O-isopropyldi-methylsilyl-2,3-di-O-ethyl)-β-cyclodextrin, heptakis(6-O-thexyldi-methylsilyl-2,3-di-O-ethyl)-β-cyclodextrin, and heptakis(6-O-cy-clohexyldimethyl-2,3-di-O-ethyl)-β-cyclodextrin (IPDE-β-CD, TXDE-β-CD, and CHDE-β-CD), were synthesized and the enan-tioselectivities of these three CD derivatives and heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-ethyl)-β-cyclodextrin (TBDE-β-CD) were compared for GC separation of a range of chiral test com-pounds. In particular TXDE-β-CD showed much higher enentio-selectivity than TBDE-β-CD. Enentioselectivities of IPDE-β-CD and CHDE-β-CD are somewhat lower than that of TXDE-β-CD and CHDE-β-Cd are somewhat lower than that of TXDE-β-CD. These observations are indicative of significant effects of subtle changes in the structure of the 6-O-substituent on the enantioselec-tivity of the β-CD derivatives. The difference in enantioselectivities of the 6-O-substituted CD derivatives were explained in terms of relative contributions of the effects of hydrophobicity and steric hindrance of the substituent to the inclusion process. CHDE-β-CD showed the lowest enantioselectivity among the threederivatives. It is likely that the unfavorable steric hindrance of the bulky cyclo-hexyl group plays a greater role than the favorable hydrophobicity effect of the cyclohexyl group in the inclusion process in CHDE-β-CD. IPDE-β-CD showed lower selectivity than TXDE-β-CD and TBDE-β-CD. In the case of these CD derivatives having acyclic substituents the relative hydrophobicity of the substituent seems to be a dominant factor affecting the inclusion process. Isopropyl groups factor affecting the inclusion process. Isopropyl groups are less hydrophobic than thexyl and tert-butyl groups.
Type of Medium: Electronic Resource
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• 4
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 16 (1995), S. 1045-1054
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: Ab initio molecular orbital (MO) calculations are carried out on the nonidentity allyl transfer processes, X- + CH2CHCH2Y ⇌ CH2CHCH2 X + Y-, with X- = H, F, and Cl and Y = H, NH2, OH, F, PH2, SH, and Cl. The Marcus equation applies well to the allyl transfer reactions. The transition state (TS) position along the reaction coordinate and the TS structure are strongly influenced by the thermodynamic driving force, whereas the TS looseness is originated from the intrinsic barrier. The intrinsic barrier, ΔE0
Type of Medium: Electronic Resource
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• 5
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 5 (1984), S. 217-224
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: The MINDO/3 calculations were performed on the potential energy profile involved in the equilibrium \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{l} {\rm crotonic acid \rightleftharpoons isocrotonic acid \rightleftharpoons but-3-enoic acid} \\ {\rm (III)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(II)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(I)} \\ {\rm } \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\to {\rm propene + CO}_{\rm 2} \\ \end{array}$$\end{document}Optimized structures of stable molecules and transition states have been determined; thermodynamic stabilities of pure acids and barriers indicated that the equilibrium can be set up from any acids. It was argued that direct decarboxylation is only conceivable from (I), since in this process a 1, 5-hydrogen shift is involved, whereas a higher barrier process of 1, 3-hydrogen shift is required in direct decarboxylations from other acids. Direct interconversion of (I) and (III) was found to be unfavorable due to a high barrier involved.
Type of Medium: Electronic Resource
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• 6
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 8 (1987), S. 794-800
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: The mechanism of the A2 acid hydrolysis of methyl carbamate was investigated using MNDO method. The reaction was found to proceed in two steps: (1) the rate-determining nucleophilic attack of water on the carbonyl carbon of the N-protonated tautomer involving the tetrahedral TS; and (2) the fast subsequent proton abstraction by the leaving group, NH3, to form products. The mechanism is similar to that involved in the A2 hydrolysis of acetamide. Effects of substituents, R1, R2, and R3 in R1OCONR2R3, on rates can be predicted by the changes in electron densities on alkoxy oxygen and N, in complete agreement with the experimental results. We concluded that there is no need for invoking two different mechanisms for amides and carbamates since a common mechanism can easily accommodate all the experimental results.
Type of Medium: Electronic Resource
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• 7
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 6 (1985), S. 79-87
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: Transition states for the two probable pathways for the gas-phase hydrolysis of hydrogen isocyanate have been determined using the MINDO/3 method. Activation barriers obtained showed that the one-step mechanism is preferred to the two-step mechanism involving an intermediate. It was shown that the reaction of polymeric water has lower activation barrier than the reaction of monomeric water. Energy and charge decomposition analysis showed that in the former less energy is required in the deformation of molecules for the transition state (TS) formation due to the cyclic flow of electronic charges in the TS.
Type of Medium: Electronic Resource
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• 8
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 6 (1985), S. 486-491
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: The hydrogen atom transfer reaction between substituted methanes (substituents; H, F, CH3, OH, and CN) and methyl radicals was studied by 4-31G (UHF) calculations using the MINDO/3 geometries. The transition state structures and energy barriers were determined, and variations of the transition state and of the reactivity due to the change of substituent were analyzed based on the potential energy surface characteristics. It was concluded that the reaction is of the SH2 type with a backside attack, and transition state variations are controlled by the vector sum of the component parallel to (Hammond rule) and one perpendicular to the reaction coordinate (anti-Hammond rule). It was also concluded that the most important factor influencing the reactivity is bond dissociation energy effect directly related to the spin transfer of the radical species, and the polar effect need not be overemphasized.
Type of Medium: Electronic Resource
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• 9
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 13 (1992), S. 595-601
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: A two-component Kramers' restricted Hartree-Fock method (KRHF) has been developed for the polyatomic molecules with closed shell configurations. The present KRHF program utilizes the relativistic effective core potentials with spin-orbit operators at the Hartree-Fock (HF) level and produces molecular spinors obeying the double group symmetry. The KRHF program enables the variational calculation of spin-orbit interactions at the HF level. KRHF calculations have been performed for the HX, X2, XY(X, Y = I, Br), and CH3I molecules. It is demonstrated that the orbital energies from KRHF calculations are useful for the interpretation of spin-orbit splittings in photoelectron spectra. In all molecules studied, bond lengths are only slightly expanded, harmonic vibrational frequencies are reduced, and bond energies are significantly decreased by the spin-orbit interactions.
Type of Medium: Electronic Resource
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• 10
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Computational Chemistry 12 (1991), S. 899-908
ISSN: 0192-8651
Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Computer Science
Notes: Free energy calculations have been performed on a variety of calcium (Ca(II)) and magnesium (Mg(II)) complexes as model systems for protein-metal, phospholipid-metal, and protein-metal-phospholipid interactions. The major goal of this work was to advance our understanding of Ca(II) ion selectivity in the blood coagulation proteins. The limitations of present force field methods as applied to divalent metal ion-containing systems is discussed. The effects of different water models, varying nonbond cutoff values, and counterions are evaluated. Additionally, the effects of complete charge transformation between predetermined quantum mechanical states is evaluated in which all of the charges of the metal complexes as well as the van der Waals radii of the metals are perturbed. Protein models include formate, malonate, ethylene-diaminetetraacetate, and 1,1,4,4 -butanetetracarboxylic acid. Phospholipid mimics included methylphosphatidylserine, methylphosphatidylcholine, dimethyl phosphate, and trans-cyclohexane-1,3-diphosphate. The present set of calculations tends to overestimate Mg(II) binding in the various test systems for which experimental results exist, an effect which may in part be due to the lack of explicit polarization/charge transfer terms for all molecules, including water, in the force field. However, these calculations support the notion that coagulation protein selectivity towards Ca(II) is likely due to a greater ease of desolvation of Ca(II) over Mg(II).