358 research outputs found
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
STRONG FIELD MOLECULAR IONIZATION: CONTROLLED DISSOCIATION IN RADICAL CATIONS WITH DYNAMIC RESONANCES AND ADIABATICALLY PREPARED LAUNCH STATES
This dissertation investigates the electronic spectroscopy of a series of alkyl phenyl ketone radical cations and the dynamics of selective launch states in the strong field regime with tunable near infrared ultrashort laser pulses from 790 nm - 1550 nm coupled to mass spectrometric detection. Our method relies on tunable strong field laser pulses in the range from 1150 nm - 1550 nm to adiabatically ioinized gas phase molecules and prepare ions in the ground ionic state that serve as a launch state for future excitation and control. Adiabatic ionization is capable of transferring little energy to the molecule and producing a majority of a parent molecular ion in comparison to nonadiabatic ionization wherein multiple ionic states can be populated with an accompanying high degree of molecular fragmentation. We measure a dynamic resonance in the low lying electronic states of the acetopheone radical cation via preparation of a launch state with adiabatic ionization followed by a one photon transition within a single pulse duration which facilitates bond dissociation to produce the benzoyl ion. Experiments on acetophenone homologues and derivatives elucidate the structural dependence of the electronic resonance and supporting ab initio calculations identify the dynamic resonance along the molecular torsional coordinate between the ground ionic state, D0, and second excited state, D2. Post ionization excitation within the pulse duration transfers the ground state wavepacket to the D2 surface where the wavepacket encounters a three state conical intersection that facilitates the preferred bond dissociation. Time resolved photodissociation experiments measure the dynamics of the launch state, large amplitude oscillations and extended coherence times support the notion that adiabatic ionization populates a majority of the ground ionic surface. Control of the dissociation products is initiated from the launch state by varying the pump wavelength and probe intensity. Elimination of the D0 wavepacket with a 1370 nm reveals additional secondary dynamics that are attributed to wavepacket motion on the D2 surface. Finally, the effect of para substitution on the acetophenone radical cation is explored as a strategy to control the launch state wavepacket dynamics. Suppresion of the wavepacket dynamics are observed with the addition of alkoxy groups whereas extended coherence of the launch state dynamics approaching ~5 ps is observed upon trifluoromethyl substitution. A possible mechanism for the extended coherenece based on coupled torsional rotors is proposed.Chemistr
The portrait of a word: The use of mental and visual images in the acquisition of form, meaning, and use of Spanish concrete nouns
Second language (L2) vocabulary learning is at the core of language learning and use. Studies have shown that native speakers and L2 learners perceive lexical errors as the biggest obstacle in effective communication (Gass & Selinker, 2008). As a result, the learning and teaching of vocabulary must be one of the focal points of L2 learning. This study quantitatively investigates the effectiveness of two vocabulary learning strategies, the keyword method and the visual support method. Using these two strategies, L2 learners can store the word's meaning both visually and linguistically by creating a "dual coding" (Paivio & Desrochers, 1981) of the word. The keyword method is a strategy that utilizes the association of a first language word (a keyword) with the unknown L2 word through the use of a mental image whereas the visual support method is a strategy that utilizes a visual image. In four L2 intact classes over a 6-day treatment period, participants learned 24 Spanish concrete nouns using both the keyword and visual support methods in one of two presentation orders. Using a pre-test, post-test, and delayed post-test design, results indicated that the use of an image, whether mental or visual, increased L2 learners' knowledge of form, meaning, and use of L2 vocabulary. Qualitative analyses of vocabulary notebooks/journals and surveys revealed that participants' preferences for and experiences with each learning method were influenced by individual likes and dislikes of each treatment. Since vocabulary acquisition is such a complex and multi-faceted process (Nation, 2001), educators have the responsibility to implement and encourage the use of various L2 vocabulary teaching and learning strategies. This research thus aims to reveal how an image can be worth a thousand words in the L2 classroom.Spanis
Why in the world would I want to talk to someone else about my culture?
[EN] This paper shares the work and observations from a task-based 6-week email exchange project between participants in Spain and the US. Though small in scale, the study offers insights for those interested in telecollaboration but face constraints on multiple fronts. Close examination of the exchanges reveal participants' engagement on multiple levels, including reflection on one's own culture.Bohinski, CA.; Leventhal, Y. (2015). Why in the world would I want to talk to someone else about my culture?. The EuroCALL Review. 23(1):11-16. doi:10.4995/eurocall.2015.4654.SWORD111623
Interstitial lung disease of infancy caused by a new NKX2‐1 mutation
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137254/1/ccr3901.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137254/2/ccr3901_am.pd
Characterization of a novel loss-of-function mutation of PAX8 associated with congenital hypothyroidism
Intra-operative MRI facilitates tumour resection during trans-sphenoidal surgery for pituitary adenomas
Background During trans-sphenoidal microsurgical resection of pituitary adenomas, the extent of resection may be difficult to assess, especially when extensive suprasellar and parasellar growth has occurred. In this prospective study, we investigated whether intra-operative magnetic resonance imaging (iMRI) can facilitate tumour resection.
Methods Twenty patients with macroadenomas, (16 non-functioning, three growth-hormone secreting and one pharmaco-resistant prolactinoma) were selected for surgery in the iMRI. The mean tumour diameter was 27 mm (range 11–41). The mean parasellar grade, according to the Knosp classification, was 2.3. Pre-operative coronal and sagittal T1-weighted and T2-weighted images were obtained. The trans-sphenoidal tumour resection was performed at the edge of the tunnel of a Signa SP 0.5-Tesla MRI. The surgeon aimed at a radical tumour resection that was followed by a peri-operative MRI scan. When a residual tumour was visualised and deemed resectable, an extended resection was performed, followed by another MRI scan. This procedure was repeated until the imaging results were satisfactory. In all patients, we were able to obtain images to assess the extent of resection and to classify the resection as either total or subtotal.
Results After primary resection, eight out of 20 cases were classified as total resections. A second resection was performed in 11 of 12 cases classified as subtotal resections, and in four of these, total resection was achieved. A third resection was performed in three of the remaining seven cases with subtotal resections, but we did not achieve total resection in any of these cases. Therefore, the use of iMRI increased the number of patients with total resection from 8/20 (40%) to 12/20 (60%). The only observed complication was a transient spinal fluid leakage.
Conclusion Intra-operative MRI during trans-sphenoidal microsurgery is useful in selected patients for a safe and more complete resection.
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited
Immunohistochemical detection and regulation of α5 nicotinic acetylcholine receptor (nAChR) subunits by FoxA2 during mouse lung organogenesis
<p>Abstract</p> <p>Background</p> <p>α<sub>5 </sub>nicotinic acetylcholine receptor (nAChR) subunits structurally stabilize functional nAChRs in many non-neuronal tissue types. The expression of α<sub>5 </sub>nAChR subunits and cell-specific markers were assessed during lung morphogenesis by co-localizing immunohistochemistry from embryonic day (E) 13.5 to post natal day (PN) 20. Transcriptional control of α<sub>5 </sub>nAChR expression by FoxA2 and GATA-6 was determined by reporter gene assays.</p> <p>Results</p> <p>Steady expression of α<sub>5 </sub>nAChR subunits was observed in distal lung epithelial cells during development while proximal lung expression significantly alternates between abundant prenatal expression, absence at PN4 and PN10, and a return to intense expression at PN20. α<sub>5 </sub>expression was most abundant on luminal edges of alveolar type (AT) I and ATII cells, non-ciliated Clara cells, and ciliated cells in the proximal lung at various periods of lung formation. Expression of α<sub>5 </sub>nAChR subunits correlated with cell differentiation and reporter gene assays suggest expression of α<sub>5 </sub>is regulated in part by FoxA2, with possible cooperation by GATA-6.</p> <p>Conclusions</p> <p>Our data reveal a highly regulated temporal-spatial pattern of α<sub>5 </sub>nAChR subunit expression during important periods of lung morphogenesis. Due to specific regulation by FoxA2 and distinct identification of α<sub>5 </sub>in alveolar epithelium and Clara cells, future studies may identify possible mechanisms of cell differentiation and lung homeostasis mediated at least in part by α<sub>5</sub>-containing nAChRs.</p
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