23 results on '"Juan L. Gomez"'
Search Results
2. Effect of Selective Lesions of Nucleus Accumbens µ-Opioid Receptor-Expressing Cells on Heroin Self-Administration in Male and Female Rats: A Study with NovelOprm1-CreKnock-in Rats
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Jennifer M. Bossert, Carlos A. Mejias-Aponte, Thomas Saunders, Lindsay Altidor, Michael Emery, Ida Fredriksson, Ashley Batista, Sarah M. Claypool, Kiera E. Caldwell, David J. Reiner, Jonathan J. Chow, Matthew Foltz, Vivek Kumar, Audrey Seasholtz, Elizabeth Hughes, Wanda Filipiak, Brandon K. Harvey, Christopher T. Richie, Francois Vautier, Juan L. Gomez, Michael Michaelides, Brigitte L. Kieffer, Stanley J. Watson, Huda Akil, and Yavin Shaham
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General Neuroscience - Abstract
The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-basedOprm1-Creknock-in transgenic rat that provides cell type-specific genetic access to MOR-expressing cells. After performing anatomic and behavioral validation experiments, we used theOprm1-Creknock-in rats to study the involvement of NAc MOR-expressing cells in heroin self-administration in male and female rats. Using RNAscope, autoradiography, and FISH chain reaction (HCR-FISH), we found no differences inOprm1expression in NAc, dorsal striatum, and dorsal hippocampus, or MOR receptor density (except dorsal striatum) or function betweenOprm1-Creknock-in rats and wildtype littermates. HCR-FISH assay showed thatiCreis highly coexpressed withOprm1(95%-98%). There were no genotype differences in pain responses, morphine analgesia and tolerance, heroin self-administration, and relapse-related behaviors. We used the Cre-dependent vector AAV1-EF1a-Flex-taCasp3-TEVP to lesion NAc MOR-expressing cells. We found that the lesions decreased acquisition of heroin self-administration in maleOprm1-Crerats and had a stronger inhibitory effect on the effort to self-administer heroin in femaleOprm1-Crerats. The validation of anOprm1-Creknock-in rat enables new strategies for understanding the role of MOR-expressing cells in rat models of opioid addiction, pain-related behaviors, and other opioid-mediated functions. Our initial mechanistic study indicates that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in male and female rats.SIGNIFICANCE STATEMENTThe brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-basedOprm1-Creknock-in transgenic rat that provides cell type-specific genetic access to brain MOR-expressing cells. After performing anatomical and behavioral validation experiments, we used theOprm1-Creknock-in rats to show that lesioning NAc MOR-expressing cells had different effects on heroin self-administration in males and females. The newOprm1-Crerats can be used to study the role of brain MOR-expressing cells in animal models of opioid addiction, pain-related behaviors, and other opioid-mediated functions.
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- 2023
3. Essential role of P-glycoprotein in the mechanism of action of oliceridine
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Emilya Ventriglia, Arianna Rizzo, Juan L. Gomez, Jacob Friedman, Sherry Lam, Oscar Solís, Rana Rais, Jordi Bonaventura, and Michael Michaelides
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Pharmacology ,Psychiatry and Mental health - Abstract
Mu opioid receptor (MOR) agonists comprise the most effective analgesics, but their therapeutic utility is limited by adverse effects. One approach for limiting such effects has been to develop "biased" MOR agonists that show preference for activating G protein over β-Arrestin signaling. However, the notion of biased agonism has been challenged by recent studies. Oliceridine (Olinvyk
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- 2022
4. 6-O-(2-[18F]Fluoroethyl)-6-O-Desmethyl-Diprenorphine ([18F]FE-DPN) Preferentially Binds to Mu Opioid Receptors In Vivo
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Marjorie R. Levinstein, Emilya N. Ventriglia, Juan L. Gomez, Reece C. Budinich, János Marton, Gjermund Henriksen, Daniel P. Holt, Robert F. Dannals, Martin G. Pomper, Carlos A. Zarate, Jordi Bonaventura, and Michael Michaelides
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Cancer Research ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
5. A tool for monitoring cell type-specific focused ultrasound neuromodulation and control of chronic epilepsy
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Keith R. Murphy, Jordan S. Farrell, Juan L. Gomez, Quintin G. Stedman, Ningrui Li, Steven A. Leung, Cameron H. Good, Zhihai Qiu, Kamyar Firouzi, Kim Butts Pauly, Butrus Pierre T. Khuri-Yakub, Michael Michaelides, Ivan Soltesz, and Luis de Lecea
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Multidisciplinary ,Epilepsy ,Epilepsy, Temporal Lobe ,Animals ,Brain ,Hippocampus ,Ultrasonography - Abstract
Focused ultrasound (FUS) is a powerful tool for noninvasive modulation of deep brain activity with promising therapeutic potential for refractory epilepsy; however, tools for examining FUS effects on specific cell types within the deep brain do not yet exist. Consequently, how cell types within heterogeneous networks can be modulated and whether parameters can be identified to bias these networks in the context of complex behaviors remains unknown. To address this, we developed a fiber Photometry Coupled focused Ultrasound System (PhoCUS) for simultaneously monitoring FUS effects on neural activity of subcortical genetically targeted cell types in freely behaving animals. We identified a parameter set that selectively increases activity of parvalbumin interneurons while suppressing excitatory neurons in the hippocampus. A net inhibitory effect localized to the hippocampus was further confirmed through whole brain metabolic imaging. Finally, these inhibitory selective parameters achieved significant spike suppression in the kainate model of chronic temporal lobe epilepsy, opening the door for future noninvasive therapies.
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- 2023
6. Author Correction: Defective HNF4alpha-dependent gene expression as a driver of hepatocellular failure in alcoholic hepatitis
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Josepmaria Argemi, Maria U. Latasa, Stephen R. Atkinson, Ilya O. Blokhin, Veronica Massey, Joel P. Gue, Joaquin Cabezas, Juan J. Lozano, Derek Van Booven, Aaron Bell, Sheng Cao, Lawrence A. Vernetti, Juan P. Arab, Meritxell Ventura-Cots, Lia R. Edmunds, Constantino Fondevila, Peter Stärkel, Laurent Dubuquoy, Alexandre Louvet, Gemma Odena, Juan L. Gomez, Tomas Aragon, Jose Altamirano, Juan Caballeria, Michael J. Jurczak, D. Lansing Taylor, Carmen Berasain, Claes Wahlestedt, Satdarshan P. Monga, Marsha Y. Morgan, Pau Sancho-Bru, Philippe Mathurin, Shinji Furuya, Carolin Lackner, Ivan Rusyn, Vijay H. Shah, Mark R. Thursz, Jelena Mann, Matias A. Avila, and Ramon Bataller
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Multidisciplinary ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology - Published
- 2023
7. Effect of selective lesions of nucleus accumbens μ-opioid receptor-expressing cells on heroin self-administration in male and female rats: a study with novelOprm1-Creknock-in rats
- Author
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Jennifer M. Bossert, Carlos A. Mejias-Aponte, Thomas Saunders, Lindsay Altidor, Michael Emery, Ida Fredriksson, Ashley Batista, Sarah M. Claypool, Kiera E. Caldwell, David J. Reiner, Jonathan J. Chow, Matthew Foltz, Vivek Kumar, Audrey Seasholtz, Elizabeth Hughes, Wanda Filipiak, Brandon K. Harvey, Christopher T. Richie, Francois Vautier, Juan L. Gomez, Michael Michaelides, Brigitte L. Kieffer, Stanley J. Watson, Huda Akil, and Yavin Shaham
- Abstract
The brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-basedOprm1-Cre knock-in transgenic rat that provides cell-type specific genetic access to MOR-expressing cells. After performing anatomical and behavioral validation experiments, we used theOprm1-Cre knock-in rats to study the role of nucleus accumbens (NAc) MOR-expressing cells in heroin self-administration in male and female rats.Using RNAscope, autoradiography, and fluorescencein situhybridization chain reaction (HCR-FISH), we found no differences inOprm1expression in NAc, dorsal striatum (DS), and dorsal hippocampus, or MOR receptor density (except DS) or function betweenOprm1-Cre knock-in rats and wildtype littermates. HCR-FISH assay showed thatiCreis highly co-expressed withOprm1(95-98%). There were no genotype differences in pain responses, morphine analgesia and tolerance, heroin self-administration, and relapse-related behaviors. We used the Cre-dependent vector AAV1-EF1a-Flex-taCasp3-TEVP to lesion NAc MOR-expressing cells and report sex-specific effects: the lesions decreased acquisition of heroin self-administration in maleOprm1-Cre rats and had a stronger inhibitory effect on the effort to self-administer heroin in femaleOprm1-Cre rats.The validation of anOprm1-Cre knock-in rat enables new strategies for understanding the role of MOR-expressing cells in rat models of opioid addiction, pain-related behaviors, and other opioid-mediated functions. Our initial mechanistic study with these rats suggests a sex-specific role of NAc MOR-expressing cells in heroin self-administration.Significance statementThe brain µ-opioid receptor (MOR) is critical for the analgesic, rewarding, and addictive effects of opioid drugs. However, in rat models of opioid-related behaviors, the circuit mechanisms of MOR-expressing cells are less known because of a lack of genetic tools to selectively manipulate them. We introduce a CRISPR-basedOprm1-Cre knock-in transgenic rat that provides cell-type specific genetic access to brain MOR-expressing cells. After performing anatomical and behavioral validation experiments, we used theOprm1-Cre knock-in rats to show a potential sex-specific role of nucleus accumbens MOR-expressing cells in heroin self-administration. The newOprm1-Cre rats can be used to study both the general and sex-specific role of brain MOR-expressing cells in animal models of opioid addiction, pain-related behaviors, and other opioid-mediated functions.
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- 2022
8. Time will tell. Reply to 'Comments to pharmacological and behavioral divergence of ketamine enantiomers by Jordi Bonaventura et al.' by Chen et al
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Jordi Bonaventura, Sherry Lam, Meghan Carlton, Matthew Boehm, Juan L. Gomez, Oscar Solís, Marta Sánchez-Soto, Patrick J. Morris, Ida Fredriksson, Craig J. Thomas, David R. Sibley, Yavin Shaham, Carlos A. Zarate, and Michael Michaelides
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Cellular and Molecular Neuroscience ,Psychiatry and Mental health ,Molecular Biology - Published
- 2022
9. The show must go on. Reply to 'Distinct functions of S-ketamine and R-ketamine in mediating biobehavioral processes of drug dependency: comments on Bonaventura et al' by Insop Shim
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Jordi Bonaventura, Sherry Lam, Meghan Carlton, Matthew Boehm, Juan L. Gomez, Oscar Solís, Marta Sánchez-Soto, Patrick J. Morris, Ida Fredriksson, Craig J. Thomas, David R. Sibley, Yavin Shaham, Carlos A. Zarate, and Michael Michaelides
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Cellular and Molecular Neuroscience ,Psychiatry and Mental health ,Molecular Biology - Published
- 2022
10. 6-O-(2-[
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Marjorie R, Levinstein, Emilya N, Ventriglia, Juan L, Gomez, Reece C, Budinich, János, Marton, Gjermund, Henriksen, Daniel P, Holt, Robert F, Dannals, Martin G, Pomper, Carlos A, Zarate, Jordi, Bonaventura, and Michael, Michaelides
- Abstract
6-O-(2-[Here, we report the first characterization of [We also show that [Taken together with prior findings, our results suggest that [
- Published
- 2022
11. Abstract P4-02-20: Utility of the 70-gene signature and 10 year follow up in patients with early-stage breast cancer in a single institution study
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Azadeh Nasrazadani, Juan L. Gomez Marti, Margaret Q. Rosenzweig, Meghan McGuire, Katie Quinn, Josien Haan, Alexandre Houzelle, Rohit Bhargava, William Audeh, and Adam M. Brufsky
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Cancer Research ,Oncology - Abstract
Introduction: Genomic tests are routinely used by clinicians to guide treatment decisions in early-stage breast cancer (EBC). The 70-gene MammaPrint assay (MP) assesses the risk of distant recurrence in untreated patients with EBC and categorizes the tumors as High Risk (HR, MP index: -1 to ≤0) or Low Risk (LR, >0 to +1). The LR category is further divided into Low but non-UltraLow (LNUL; >0 to ≤0.355) and UltraLow Risk (UL; >0.355 to 1). Here, we report the risk of distant recurrence by MP and 10-year outcomes in patients with EBC diagnosed at Magee Women’s Hospital of the University of Pittsburgh Medical Center. Methods: In this retrospective analysis, 259 women diagnosed with EBC between 2005 and 2008, who received a MP result, were included. Patient clinical and tumor characteristics were collected. The median FU was 13.1 year among patients with clinical data. Treatment received, 10-year Distant Metastasis Free Interval (DMFI) and 10-year Breast Cancer Specific Survival (BCSS) are reported according to the MP groups. Differences in DMFI and BCSS between MP risk groups were assessed by log-rank. Patients were treated at the physician’s discretion. Treatment was started prior to obtaining MammaPrint results. Results: Among the 259 patients, 69% were post-menopausal women (mean [range] age: 58 [31-81] years) and diagnosed with hormone receptor-positive HER2-negative tumors (90%), grade 1 or 2 (64%), and without lymph node invasion (93%). In this cohort, 69% (n = 159) had a MP LR result and 31% (n = 100) had a MP HR result. Overall, 14% (n = 35) of patients had a MP UL risk of recurrence of whom 74% (n = 26/35) were post-menopausal women. Substantially more patients received chemotherapy in the HR group (57%, n = 57) compared with the LR group (15%, n = 24) (table). Considering that treatment was initiated before MammaPrint results were known, MP results might have allowed chemotherapy de-escalation in in 15% (n = 24) of patients with a MP LR. Similarly, in the 39% (n = 39) of women with a MP HR treated with endocrine therapy only, knowledge of MP results could have provided important information to add chemotherapy to the treatment plan.. In the MP UL group, 74 % (n = 26) of patients were treated with endocrine therapy only compared with those who received chemotherapy (9%, n = 3) and no adjuvant treatment (9%, n = 3). The 10-year DMFI and 10-year BCSS were higher in the LR compared with the HR group (table). When further stratifying the MP LR group in LNUL and UL, the 10y DMFI was 0.97 (95% CI; 0.94 – 1.00) and 1.00 for the MP LNUL and UL groups, respectively. Within the first 10 years, 8 of the 10 distant recurrences observed were in the MP HR group, and 2 were in the MP LNUL group. Among the 18 recorded deaths, 5 were breast cancer-related, 4 in the MP HR and 1 in the MP LR (LNUL) groups. Discussion: In this single-institution retrospective analysis, all patients showed excellent BCSS and DMFI outcomes confirming the ability of MP to correctly predict the good prognosis (LR) and poor prognosis (HR) in patients with EBC. In this analysis, as observed in other cohorts, women with a MP UL risk result had an excellent prognosis at 10 years while being treated mostly with endocrine therapy only. Taken together, with the low endocrine therapy adherence reported in the literature, these data suggest that patients with a MP UL result may be candidates for further treatment de-escalation to optimize the risk/benefit ratio of endocrine therapy in future studies. Table 1. Clinical outcomes and treatment received in patients stratified by MammaPrint results * Patients were treated at the physician’s discretion a p = 0.011, MP LR vs MP HR. b p = 0.032, MP UL vs LNUL vs HR. c p = 0.061 MP LR vs MP HR. d p = 0.170, MP UL vs LNUL vs HR. Citation Format: Azadeh Nasrazadani, Juan L. Gomez Marti, Margaret Q. Rosenzweig, Meghan McGuire, Katie Quinn, Josien Haan, Alexandre Houzelle, Rohit Bhargava, William Audeh, Adam M. Brufsky. Utility of the 70-gene signature and 10 year follow up in patients with early-stage breast cancer in a single institution study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-20.
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- 2023
12. Endoscopic endonasal clipping of a medial paraclinoid aneurysm with roadmapping assistance: Two-dimensional operative video
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Marcos V. Sangrador-Deitos, German Lopez-Valencia, Gerardo Y. Guinto-Nishimura, Aldo G. Eguiluz-Melendez, Samuel Romano-Feinholz, and Juan L. Gomez-Amador
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Surgery ,Neurology (clinical) - Abstract
Background: Advancements in endoscopic endonasal approaches (EEAs) allow the treatment of a wide variety of diseases including vascular pathology. Case Description: A 56-year-old woman presented with thunderclap headache due to two aneurysms: Communicating segment of left internal carotid artery (ICA) and medial paraclinoid (Baramii IIIB). The ICA aneurysm was clipped through a conventional transcranial approach; the paraclinoid aneurysm was successfully clipped using an EEA guided with roadmapping assistance. Conclusion: EEA is useful to treat aneurysms in selected cases and the use of adjuvant angiographical techniques such as roadmapping or proximal balloon control allow excellent control during the procedure.
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- 2023
13. Pharmacological and behavioral divergence of ketamine enantiomers: implications for abuse liability
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Jordi, Bonaventura, Sherry, Lam, Meghan, Carlton, Matthew A, Boehm, Juan L, Gomez, Oscar, Solís, Marta, Sánchez-Soto, Patrick J, Morris, Ida, Fredriksson, Craig J, Thomas, David R, Sibley, Yavin, Shaham, Carlos A, Zarate, and Michael, Michaelides
- Subjects
Depressive Disorder, Treatment-Resistant ,Mice ,Depression ,Animals ,Ketamine ,Stereoisomerism ,Antidepressive Agents ,Rats - Abstract
Ketamine, a racemic mixture of (S)-ketamine and (R)-ketamine enantiomers, has been used as an anesthetic, analgesic and more recently, as an antidepressant. However, ketamine has known abuse liability (the tendency of a drug to be used in non-medical situations due to its psychoactive effects), which raises concerns for its therapeutic use. (S)-ketamine was recently approved by the United States' FDA for treatment-resistant depression. Recent studies showed that (R)-ketamine has greater efficacy than (S)-ketamine in preclinical models of depression, but its clinical antidepressant efficacy has not been established. The behavioral effects of racemic ketamine have been studied extensively in preclinical models predictive of abuse liability in humans (self-administration and conditioned place preference [CPP]). In contrast, the behavioral effects of each enantiomer in these models are unknown. We show here that in the intravenous drug self-administration model, the gold standard procedure to assess potential abuse liability of drugs in humans, rats self-administered (S)-ketamine but not (R)-ketamine. Subanesthetic, antidepressant-like doses of (S)-ketamine, but not of (R)-ketamine, induced locomotor activity (in an opioid receptor-dependent manner), induced psychomotor sensitization, induced CPP in mice, and selectively increased metabolic activity and dopamine tone in medial prefrontal cortex (mPFC) of rats. Pharmacological screening across thousands of human proteins and at biological targets known to interact with ketamine yielded divergent binding and functional enantiomer profiles, including selective mu and kappa opioid receptor activation by (S)-ketamine in mPFC. Our results demonstrate divergence in the pharmacological, functional, and behavioral effects of ketamine enantiomers, and suggest that racemic ketamine's abuse liability in humans is primarily due to the pharmacological effects of its (S)-enantiomer.
- Published
- 2020
14. Supracerebellar Infratentorial and Occipital Transtentorial Approaches to the Pulvinar: Ipsilateral Versus Contralateral Corridors
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Aaron A. Cohen-Gadol, Joao T Alves-Belo, Salomon Cohen-Cohen, Kushal J. Shah, Juan C. Fernandez-Miranda, and Juan L Gomez-Amador
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Microsurgery ,Surgical approach ,Free edge ,business.industry ,Anatomy ,Neurovascular bundle ,Pulvinar ,Neurosurgical Procedures ,Tentorium ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,Humans ,Surgery ,Neurology (clinical) ,Cadaveric spasm ,Internet of Things ,business ,Craniotomy ,030217 neurology & neurosurgery ,Parahippocampal gyrus - Abstract
Background Due to the critical neurovascular structures that surround the pulvinar, deciding the best surgical approach can be challenging, with multiple options available. Objective To analyze and compare the ipsilateral vs the contralateral version of the 2 main approaches to the cisternal pulvinar surface: paramedian supracerebellar infratentorial (PSCI) and interhemispheric occipital transtentorial (IOT). Methods The PSCI and IOT approaches were performed on 7 formalin-fixed adult cadaveric heads to evaluate qualitatively and quantitatively the microsurgical exposure of relevant anatomic structures. We quantitatively measured the corridor distance to our target with each approach. Results The ipsilateral PSCI approach provided an easier access and a better exposure of the anteromedial portion of the cisternal pulvinar surface. The contralateral approach provided a wider and more accessible exposure of the posterolateral portion of the cisternal pulvinar surface. When protrusion of the posterior parahippocampal gyrus above the free edge of the tentorium was present, the contralateral PSCI approach provided an unobstructed view to both areas. The IOT approach provided a better view of the anteromedial portion of the cisternal pulvinar surface, especially with a contralateral approach. Conclusion Multiple approaches to the pulvinar have been described, modified, and improved. Based on this anatomic study we believe that although the corridor distance with a contralateral approach is longer, the surgical view and access can be better. We recommend the use of a PSCI contralateral approach especially when a significant protrusion of the posterior parahippocampal gyrus is present.
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- 2018
15. List of Contributors
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Anthony P. Auger, Jill B. Becker, Kristen M. Culbert, Kelly M. Dumais, Yosefa Ehrlich, Liisa A.M. Galea, Juan L. Gomez, Gian D. Greenberg, Robert J. Handa, Ashley A. Keiser, Kelly L. Klump, Victoria N. Luine, Lisa Y. Maeng, Anna M. Malysz, Shailaja K. Mani, Christian J. Merz, Mohammed R. Milad, Gretchen N. Neigh, Christina L. Nemeth, Mario G. Oyola, Adam N. Perry, Sarah E. Racine, Doodipala Samba Reddy, Meighen Roes, Sydney A. Rowson, Jaclyn M. Schwarz, Farida Sohrabji, Brian C. Trainor, Natalie C. Tronson, Alexa H. Veenema, Deborah J. Walder, C. Jane Welsh, Christel Westenbroek, Oliver T. Wolf, and Beril Yaffe
- Published
- 2016
16. Friedman's Excess energy and the McMillan-Mayer theory of solutions:Thermodynamics
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Juan L. Gomez-Estevez and Universitat de Barcelona
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Work (thermodynamics) ,Real gas ,Chemistry ,General Chemical Engineering ,Closed system ,Electrolyte solutions ,Order (ring theory) ,Thermodynamics ,Liquids ,General Chemistry ,Solucions electrolítiques ,Líquids ,Grand canonical ensemble ,Mecànica estadística ,Virial expansion ,Termodinàmica ,Statistical physics ,Well-defined ,Statistical mechanics ,Energy (signal processing) - Abstract
In his version of the theory of multicomponent systems, Friedman used the analogy which exists between the virial expansion for the osmotic pressure obtained from the McMillan–Mayer (MM) theory of solutions in the grand canonical ensemble and the virial expansion for the pressure of a real gas. For the calculation of the thermodynamic properties of the solution, Friedman proposed a definition for the “excess free energy” that is a reminder of the ancient idea for the “osmotic work”. However, the precise meaning to be attached to his free energy is, within other reasons, not well defined because in osmotic equilibrium the solution is not a closed system and for a given process the total amount of solvent in the solution varies. In this paper, an analysis based on thermodynamics is presented in order to obtain the exact and precise definition for Friedman’s excess free energy and its use in the comparison with the experimental data.
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- 2012
17. Viscosity of Liquid Water via Equilibrium Molecular Dynamics Simulations
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Juan L. Gomez, Juan S. Medina, Begoña González, J. V. Alemán, María Elisa Cuyás de Torres, Rita Prosmiti, Pablo Villarreal, Pablo Sangrà, Jóse J. Santana, Gabriel Winter, and Gerardo Delgado-Barrio
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Physics::Fluid Dynamics ,Molecular dynamics ,Water dimer ,Liquid water ,Chemistry ,Polarizability ,Intermolecular potential ,Ab initio ,Physical chemistry ,Thermodynamics - Abstract
Molecular dynamics simulations were carried out for liquid water in the NVE ensemble for calculating shear and bulk viscosities. We used two different intermolecular potential functions for the water dimer: the empirical SPCE model and the ab initio NCC one. The results obtained are compared with the available experimental values, and show that for a more accurate description of these macroscopic liquid properties a polarizable (rigid or flexible) interaction potentials should be employed. Such models, based on ab initio data, have been recently developed, and their incorporation for the viscosity calculations is discussed.
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- 2008
18. Simple statistical mechanics of electrolytes with a concentration dependent dielectric constant. Part 1. The pressure equation
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Juan L. Gomez-Estevez, José María Lombardero Martín, and M. Canales
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Permittivity ,Molality ,Chemistry ,Biophysics ,Thermodynamics ,Statistical mechanics ,Dielectric ,Electrolyte ,Radial distribution function ,Biochemistry ,Solvent ,Osmotic coefficient ,Physical and Theoretical Chemistry ,Molecular Biology - Abstract
We have used an approximation of the Adelman's theory of solutions to take into account the non-pairwise additive effects on the interaction potentials for a real electrolyte solution. As a result, a solute concentration dependent dielectric constante ρ appears. The comparison with experimental data is done by means of the pressure equation. The influence ofe ρ on solution properties is analyzed in two molality ranges using as a reference simplified models but with the dielectric constant of the pure solvent ɛ instead ofe ρ.
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- 1987
19. A new evaluation of the relative apparent molar enthalpies of KCl in water at 298.15 K
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Juan L. Gomez-Estevez and A. Sanahuja
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Molar ,Molality ,Aqueous solution ,Chemistry ,Enthalpy ,Thermodynamics ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Instrumentation ,Enthalpy change of solution ,Dilution - Abstract
The differential enthalpies of solution of KCl in water at 298.15 K were measured in the molality range 0.05–4.03 mol kg−1. From the experimental results, the molality dependence of the relative apparent molar enthalpy Lφ(m) was obtained. The comparison with Parker values for Lφ showed discrepancies as great as 7% at m = 4 mol kg−1. An extensive analysis of the literature data gave similar differences when the differential and integral enthalpies of solution were considered. From the enthalpies of dilution no definitive conclusions could be drawn because of the lack of precise data at higher molalities. Finally, from the analysis of the whole enthalpy data set for KCl (aq.) at 298.15 K a new molality dependence for Lφ is proposed.
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- 1987
20. The influence of the extrapolation method on enthalpies of solution at infinite dilution
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Juan L. Gomez-Estevez and A. Sanahuja
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Molality ,Aqueous solution ,Chemistry ,Enthalpy ,Extrapolation ,Thermodynamics ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Instrumentation ,Dilution ,Enthalpy change of solution - Abstract
Analyses have been performed on solution enthalpy data for KCl and NaCl in water at 298.15 K in the molality range below 1 mol kg −1 . In order to calculate the enthalpy of solution at infinite dilution. Δ H ∞ , the available data have been extrapolated using five different methods. The influence of the extrapolation method on Δ H ∞ has been discussed taking into account the discrepancies between the different data sets.
- Published
- 1985
21. Enthalpies of solution of RbCl in water at 298.15 K and low molalities
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A. Sanahuja and Juan L. Gomez-Estevez
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Molality ,Chemistry ,Inorganic chemistry ,Enthalpy ,Extrapolation ,Thermodynamics ,Calorimetry ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Instrumentation ,Enthalpy change of solution ,Dilution - Abstract
The enthalpies of solution of RbCl in water have been measured at 298.15 K in the molality range 0.003–0.095 mol kg−1. The molality range was extended to lower concentrations with respect to previous works in the literature to obtain a better extrapolation to infinite dilution. After treating all the data, a new value for the enthalpy of solution at infinite dilution, ΔsolH∞m has been obtained.
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- 1989
22. Molality dependence of the differential enthalpies of solution of rubidium bromide in water at 298.15 K
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A. Sanahuja and Juan L. Gomez-Estevez
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Molality ,Molar concentration ,Aqueous solution ,Chemistry ,General Chemical Engineering ,Enthalpy ,Inorganic chemistry ,Analytical chemistry ,Rubidium bromide ,Halide ,General Chemistry ,Calorimetry ,Calorimeter ,chemistry.chemical_compound - Abstract
The authors describe the differential enthalpies of solution of RbBr in water at 298.15{Kappa} measured in the molality range 0.1-5.0 mol kg/sup -1/. The experimental system was a Tian-Calvet calorimeter type adapted to this particular case and tested in previous works. From the experimental results the molality dependence of the relative apparent molar enthalpy Lphi (m) has been obtained up to 5.0 mol kg/sup -1/.
- Published
- 1989
23. Experimental study at low molalities of the enthalpies of solution of rubidium bromide in water at 298.15 K
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A. Sanahuja and Juan L. Gomez-Estevez
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Molality ,Aqueous solution ,General Chemical Engineering ,Enthalpy ,Inorganic chemistry ,Rubidium bromide ,Analytical chemistry ,Halide ,General Chemistry ,Calorimeter ,Enthalpy change of solution ,Dilution ,chemistry.chemical_compound ,chemistry - Abstract
Using the calorimeter and procedure described in a previous work, the authors' measured the enthalpy of solution of RbBr in water at 298.15 K in the molality range from 0.006 to 0.072 mol Kg/sup -1/. The results and the available data in the literature have been analyzed by two methods. As a result, the proposed value for the enthalpy of solution at infinite dilution is ..delta..H/sub s/infinity(298.15 K) = (22 179 +. 28) J mol/sup -1/.
- Published
- 1986
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