bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radial artery access technique evaluation trial: Randomized comparison of seldinger versus modified seldinger technique for arterial access for transradial catheterization
Authors: Pancholy Samir B. , Sanghvi Kintur A. , Patel Tejas M. 
Published: March 2012

AbstractBackground: Radial artery access for transradial catheterization is obtained using either Seldinger or modified Seldinger technique. There is no comparative evaluation of the safety and benefits of these two techniques. Methods: Four hundred twelve patients undergoing transradial catheterization were randomized to group I (n = 210) Seldinger technique, and group II (n = 202) modified Seldinger technique. Demographic and procedural data were collected at the time of the procedure. Data on hematoma and radial artery occlusion (RAO) were recorded at 24 hr and 30 days after the procedure. Results: Age, gender, weight, height, and history of diabetes mellitus were comparable between groups I and II. Access time (78.3 ± 37.7 sec vs. 134.2 ± 87.5 sec, P < 0.001), procedure time (17.1 ± 6.4 min vs. 19.3 ± 7.1 min, P < 0.01), number of attempts to get access (1.7 ± 0.8 vs. 2.2 ± 0.8, P < 0.001), were significantly different favoring group I. Access was obtained at first attempt in 53% of patients in group I compared with 16% in group II (P < 0.001). Change in technique (crossover) was required in 10.8% of group II patients, compared with no crossover in group I (P < 0.0001). Incidence of hematoma (0.5% vs. 1.5%, P > 0.2) and 30‐day RAO (4.3% vs. 3.9 %, P > 0.5) was similar between groups I and II. Conclusions: Seldinger technique is a faster and more predictable radial artery access technique compared with modified Seldinger technique with no increase in bleeding or RAO. © 2012 Wiley Periodicals, Inc.
The use of three‐dimensional rotational angiography to assess the pulmonary circulation following cavo‐pulmonary connection in patients with single ventricle
Authors: Berman Darren P. , Khan Danyal M. , Gutierrez Yunin , Zahn Evan M. 
Published: March 2012

AbstractBackgroundBi‐plane angiography is the gold standard for imaging the pulmonary arteries (PAs) after cavo‐pulmonary connection (CPC). Three‐dimensional rotational angiography (3DRA) is emerging technology that we hypothesized may enhance diagnostic capabilities in this patient group.MethodsRetrospective review of patients who underwent 3DRA to assess the PAs after CPC. 3DRA images were examined for diagnostic quality and compared, both qualitatively and quantitatively with corresponding 2D images.ResultsBetween 1/2010 and 12/2010, 37 3DRAs were obtained in 32 pts with prior CPC. Median age and weight were 4.3 years (0.3–19) and 15.7 kg (4.3–114). Previous surgery included: bi‐directional Glenn (16), bilateral bi‐directional Glenn (2), and Fontan (14). Thirty‐three (89%) acquisitions in 28 pts were of diagnostic quality. In 19/28 pts (68%) 3DRA provided significant additional information pertaining to 22 lesions when compared with bi‐plane angiography. These included delineating the mechanism of PA stenosis in 13 (aortic compression: 7, PA torsion: 6), demonstrating a discrete PA stenosis not seen or under appreciated on corresponding 2D images in 9. This additional information led to the performance of 9 interventions (stent implantation 8, angioplasty 1). Corresponding 2D and 3DRA images of the right and left PA were compared using quantitative analysis with a correlation coefficient of 0.94 (P < 0.001) and 0.97 (P < 0.001), for the right and left PAs respectively.Conclusions3DRA can be performed safely and effectively following CPC and may be more sensitive in diagnosing PA stenoses than 2D angiography. Quantitative measurements of PA diameter using 3DRA correlates well with 2D angiography. © 2012 Wiley Periodicals, Inc.
Coil embolization of left coronary artery pseudoaneurysms arising as a complication of percutaneous coronary intervention
Authors: Sallam Tamer , Levi Daniel , Tobis Jonathan 
Published: March 2012

AbstractCoronary aneurysms and pseudoaneurysms have been described as rare complications following percutaneous coronary intervention (PCI). There is limited data available on the optimal treatment strategy for these conditions. Use of noninvasive techniques including covered stents has been described as a potential therapeutic strategy. We report a case of percutaneous coil embolization of two enlarging left anterior descending pseudoaneurysms arising as a complication of PCI. © 2012 Wiley Periodicals, Inc.
Enhancement Factor for Gas Absorption in a Finite Liquid Layer. Part 1: Instantaneous Reaction in a Liquid in Plug Flow
Authors: Yue J. , Rebrov E. V. , Schouten J. C. 
Published: March 2012

AbstractAn approximate analysis of gas absorption with instantaneous reaction in a liquid layer of finite thickness in plug flow is presented. An approximate solution to the enhancement factor for the case of unequal diffusivities between the dissolved gas and the liquid reactant has been derived and validated by numerical simulation. Depending on the diffusivity ratio of the liquid reactant to the dissolved gas (γ), the enhancement factor tends to be either lower or higher than the prediction of the classical enhancement factor equation based on the penetration theory (Ei,pen) at Fourier numbers typically larger than 0.1. An empirical correlation valid for all Fourier numbers is proposed to allow a quick estimation of the enhancement factor, which describes the prediction of the approximate solution and the simulation data with a relative error below 5 % under the investigated conditions (γ = 0.3–4, Ei,pen = 2–1000).
ChemInform Abstract: New Strategy to the Controllable Synthesis of CuInS2 Hollow Nanospheres and Their Applications in Lithium Ion Batteries.
Authors: Zhang Weixin , Zeng Hui , Yang Zeheng , Wang Qiang 
Published: March 2012

AbstractCuInS2 hollow nanospheres are prepared from an aqueous solution containing a Cu2O nanosphere precursor, Na2S, and InCl3 (autoclave, 170 °C, 24 h).
ChemInform Abstract: The Hunt for LaFeSbO: Synthesis of La2SbO2 and a Case of Mistaken Identity.
Authors: Muir Sean , Vielma Jason , Schneider Guenter , Sleight A. W. , Subramanian M. A. 
Published: March 2012

AbstractIn the course to prepare LaFeSbO, La2SbO2 is obtained from the solid state reaction of La2O3, La, and Sb (evacuated silica tube, 1223 K, 12—18 h).
ChemInform Abstract: Yb4LiGe4 — A Yb Mixed Valent Zintl Phase with Strong Electronic Correlations.
Authors: Peter Sebastian C. , Disseler Steven M. , Svensson J. Niclas , Carretta Pietro , Graf Michael J. 
Published: March 2012

AbstractYb4LiGe4 and Yb5Ge4 are prepared from the elements in stoichiometric ratios (high frequency furnace, Ta ampules, 1070 K, 20 min).
ChemInform Abstract: [La(UO2)V2O7] [(UO2)(VO4)] the First Lanthanum Uranyl—Vanadate with Structure Built from Two Types of Sheets Based upon the Uranophane Anion‐Topology.
Authors: Mer A. , Obbade S. , Rivenet M. , Renard C. , Abraham F. 
Published: March 2012

AbstractPolycrystalline samples of the new title compound are synthesized by solid state reaction of LaCl3, U3O8, and V2O5 (Pt crucible, 800 °C, 14 d).
ChemInform Abstract: Intermolecular Oxidative C—N Bond Formation under Metal‐Free Conditions: Control of Chemoselectivity Between Aryl sp2 and Benzylic sp3 C—H Bond Imidation.
Authors: Kim Hyun Jin , Kim Jiyu , Cho Seung Hwan , Chang Sukbok 
Published: March 2012

AbstractArenes undergo efficient imidation in the presence of Ph‐I(OAc)2.
ChemInform Abstract: Elimination versus Ring Opening: A Convergent Route to Alkylidene‐Cyclobutanes.
Authors: Brioche Julien , Michalak Michal , Quiclet‐Sire Beatrice , Zard Samir Z. 
Published: March 2012

AbstractFunctionalized alkylidene‐cyclobutanes (VI), (VIII), and (XI) are prepared from 2‐fluoropyridinyl‐6‐oxy precursors (IV) derived from vinyl cyclobutanols by a radical addition—elimination process.
ChemInform Abstract: Using Nazarov Electrocyclization of Stage Chemoselective [1,2]‐Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones.
Authors: Leboeuf David , Huang Jie , Gandon Vincent , Frontier Alison J. 
Published: March 2012

AbstractThe title process is based on a stereospecific Cu(II)‐mediated Nazarov cyclization/Wagner—Meerwein rearrangement.
ChemInform Abstract: Ionic‐Surfactant‐Coated Burkholderia cepacia Lipase as a Highly Active and Enantioselective Catalyst for the Dynamic Kinetic Resolution of Secondary Alcohols.
Authors: Kim Hyunjin , Choi Yoon Kyung , Lee Jusuk , Lee Eungyeong , Park Jaiwook , Kim Mahn‐Joo 
Published: March 2012

AbstractThe commercially available lipase PS is purified and lyophilized in the presence of an ionic surfactant to provide significantly enhanced activity.
ChemInform Abstract: Copper‐Catalyzed Aerobic Oxidative Coupling of Aryl Acetaldehydes with Anilines Leading to α‐Ketoamides.
Authors: Zhang Chun , Xu Zejun , Zhang Liangren , Jiao Ning 
Published: March 2012

AbstractOptimized conditions are developed for the title reaction including the orexin receptor antagonist (X).
ChemInform Abstract: Facile Synthesis of γ‐Alkenylbutenolides from Baylis—Hillman Adducts: Consecutive In‐Mediated Barbier Allylation, PCC Oxidation, Isomerization, and Zn‐Mediated Barbier Allylation.
Authors: Lim Jin Woo , Kim Ko Hoon , Park Bo Ram , Kim Jae Nyoung 
Published: March 2012

AbstractA convenient four‐step procedure is developed for the synthesis of γ‐alkenylbutenolides (VII), (IX) and (XI).
ChemInform Abstract: Unusual Ester‐Directed Regiochemical Control in endo‐Selective Asymmetric 1,3‐Dipolar Cycloadditions of Azomethine Ylides with β‐Sulfonyl Acrylates.
Authors: Tong Min‐Chao , Li Jun , Tao Hai‐Yan , Li Yu‐Xue , Wang Chun‐Jiang 
Published: March 2012

AbstractOne of the key features of this ester‐controlled endo‐selective 1,3‐dipolar cycloaddition is that high yields and excellent selectivities are observed for a range of imino esters, especially imino esters derived from α‐substituted amino acids.
ChemInform Abstract: Identification of Indoline‐2‐thione Analogues as Novel Potent Inhibitors of α‐Melanocyte Stimulating Hormone Induced Melanogenesis.
Authors: Thanigaimalai Pillaiyar , Lee Ki‐Cheul , Sharma Vinay Kumar , Sharma Niti , Roh Eunmiri , Kim Youngsoo , Jung Sang‐Hun 
Published: March 2012

AbstractCompounds of type (IV) show an effective inhibitory activity on melanin synthesis without any cytotoxicity in melanoma B 16 cells.
ChemInform Abstract: Nitrile Oxide 1,3‐Dipolar Cycloaddition by Dehydration of Nitromethane Derivatives under Continuous Flow Conditions.
Authors: Brasholz Malte , Saubern Simon , Savage G. Paul 
Published: March 2012

AbstractAliphatic nitril oxides are generated in situ and reacted with dipolarophiles using continuous flow techniques.
ChemInform Abstract: One‐Pot Chemoselective Synthesis of Novel Fused Pyrimidine Derivatives.
Authors: Heravi M. M. , Saeedi M. , Beheshtiha Y. S. , Oskooie H. A. 
Published: March 2012

Abstract4‐Hydroxycoumarin chemoselectively react with aromatic aldehydes and 2‐aminobenzimidiazole, 3‐amino‐1H‐1,2,4‐triazole, or 6‐aminouracil to give chromenopyrimidineone (IV), triazolopyrimidinone (VII), and pyridopyrimidinetrione derivatives (X), respectively.
ChemInform Abstract: BF3·OEt2‐Catalyzed Reaction of Donor—Acceptor Cyclobutanes with Terminal Alkynes: Single‐Step Access to 2,3‐Dihydrooxepines.
Authors: Machin Ben P. , Pagenkopf Brian L. 
Published: March 2012

AbstractTreatment of the cyclobutane derivative (I) with alkynes (II) involves BF3‐mediated cyclobutane ring opening followed by reaction with (II) and rearrangement of the zwitterionic intermediate to provide oxepine derivatives (III).
ChemInform Abstract: Synthesis, Structure Characterization, and X‐Ray Crystallography of Novel 1‐Benzyl‐3‐phenyl‐1H‐pyrazole‐5‐carboxylate Derivatives with a Carbohydrate Moiety.
Authors: Lian Song , Liu Jin‐Ting , Zheng Liang‐Wen , Liu Wei‐Yong , Zhao Bao‐Xiang 
Published: March 2012

AbstractTitle derivatives (III) are prepared by the reaction of the acetylated α‐D‐xylopyranosyl bromide and the corresponding pyrazole‐based carboxylic acid in the presence of sodium bicarbonate and tetrabutylammonium bromide in moderate yields.
ChemInform Abstract: New Milbemycins from Mutant Streptomyces bingchenggensis X‐4.
Authors: Zhang Bao‐Xin , Zhang Hui , Wang Xiang‐Jing , Wang Ji‐Dong , Liu Chong‐Xi , Xiang Wen‐Sheng 
Published: March 2012

AbstractThree new compounds, milbemycin β15 (I), seco‐milbemycins E (IIa), and F (IIb) are isolated from the fermentation broth of S.
Compressed Development and Implementation of Innovations
Authors: Rähse Wilfried 
Published: March 2012

AbstractIm globalen Markt ist zur Verbesserung der Wettbewerbsfähigkeit ein schnelles Umsetzen innovativer Produktideen notwendig. Der Innovator erzielt höhere Preise, gewinnt Marktanteile und profitiert vom positiven Image. Entwicklung in der halben Zeit erfordert nicht nur die Unterstützung des Topmanagements, sondern auch die sofortige Einbeziehung des Kunden. Das Projekt sollte über ein Kernteam, bestehend aus einem Produkt‐ und Verfahrensentwickler sowie einem Mitarbeiter des Marketings, gesteuert werden. Zeit lässt sich durch kompetentes, paralleles Bearbeiten der Teilprojekte sowie durch eine Reduzierung der Versuche zur Auslegung von Maschinen und Apparaten gewinnen. Entscheidend für den Erfolg sind die Kommunikation im Team und mit der Führung sowie der unbedingte Wille, ein neues Produkt in den Markt zu bringen.
Synthesis and Structure of Binuclear O/S‐Bridged Organobismuth Complexes and Their Cooperative Catalytic Effect on CO2 Fixation
Authors: Qiu Renhua , Meng Zhengong , Yin Shuangfeng , Song Xingxing , Tan Nianyuan , Zhou Yongbo , Yu Kun , Xu Xinhua , Luo Shenglian , Au Chak‐Tong , Wong Wai‐Yeung 
Published: March 2012

AbstractIn the synthesis of binuclear organobismuth complexes (1–6) through treatment of organobismuth chlorides with NaOH or Na2S⋅9H2O, the two 5,6,7,12‐tetrahydrodibenz [c,f][1,5]azabismocine frameworks are cross‐linked by either a sulfur or an oxygen atom. The complexes (1–6) show high catalytic efficiency in the synthesis of cyclic carbonates from 2‐(chloromethyl)oxirane and CO2. Compared with their precursor chlorides (7–9), methoxide 10 and methanethioate 11 which are mononuclear organobismuth complexes, the binuclear organobismuth complexes show higher cooperative catalytic effect. However, the complexes with an oxygen bridge (1–3) are not stable in air and lose their catalytic efficiency because of hydrolysis or CO2 adsorption (forming organobismuth carbonates in the latter case). Nonetheless, the binuclear organobismuth complexes (4–6) with a sulfur bridge are highly stable in air and can be applied in the synthesis of cyclic carbonates (with the co‐presence of Bu4NI) across various kinds of epoxides, thus exhibiting satisfactory efficiency and selectivity.
Water‐Soluble Copper(II) Complexes with a Sulfonic‐Functionalized Arylhydrazone of β‐Diketone and Their Application in Peroxidative Allylic Oxidation of Cyclohexene
Authors: Mizar Archana , Guedes da Silva M. Fátima C. , Kopylovich Maximilian N. , Mukherjee Sanghamitra , Mahmudov Kamran T. , Pombeiro Armando J. L. 
Published: March 2012

AbstractThe reaction of CuII acetate with the new sulfo‐functionalized arylhydrazone of β‐diketone 2‐[2‐(4,4‐dimethyl‐2,6‐dioxocyclohexylidene)hydrazinyl]benzenesulfonic acid (H2L, 1) in aqueous methanol solution led to the formation of the 2D coordination polymer {[Cu4(1κ2O,κN:2κO,κN‐L)4(μ‐OH2)2]·H2O}n (2). However, when the reaction was peformed in the presence of the N‐containing species cyanoguanidine (cyg), 3,5‐dimethyl‐1H‐pyrazole (dp), 2,2′‐bipyridine (bpy) or pyrazine (py), the mononuclear (H3O+)2[Cu(κ2O,κN‐L)2] (4), [Cu(κ2O,κN‐L)(dp)2] (3) or [Cu(κ2O,κN‐L)(κ2N‐bpy)] (5) or dinuclear [{Cu(κ2O,κN‐L)(H2O)}2(κ‐py)]·CH3OH (6) complexes were obtained, respectively. The compounds were characterized by elemental analysis, IR spectroscopy, single‐crystal X‐ray diffraction analysis and, for 1, by 1H and 13C NMR spectroscopy. The CuII complexes 2–6 act as catalyst precursors for the selective peroxidative (with TBHP) allylic oxidation of cyclohexene to cyclohex‐2‐enol (Cy‐ol) and cyclohex‐2‐enone (Cy‐one), formed in a Cy‐one/Cy‐ol ratio of up to 9 with total yields of around 70 % and TONs of up to 350.
A General Synthesis of Indole‐3‐carboxylic Esters by Palladium‐Catalyzed Direct Oxidative Carbonylation of 2‐Alkynylaniline Derivatives
Authors: Gabriele Bartolo , Veltri Lucia , Mancuso Raffaella , Salerno Giuseppe , Costa Mirco 
Published: March 2012

AbstractA general synthesis of indole‐3‐carboxylic esters by direct Pd‐catalyzed oxidative carbonylation of readily available 2‐alkynylaniline derivatives is reported. In particular, 2‐alkynylanilines bearing an internal triple bond and a secondary amino group (1) were directly converted into indole‐3‐carboxylic esters 2 in fair to good yields (50–84 %) when let to react with CO, O2, and an alcohol in the presence of the PdI2/KI catalytic system, under relatively mild conditions [100 °C and 20 atm (at 25 °C) of a 4:1 mixture CO/air]. On the other hand, under similar conditions, but in the presence of HC(OMe)3, 2‐alkynylanilines bearing an internal triple bond and a primary amino group (7) afforded 1‐(dimethoxymethyl)indole‐3‐carboxylic esters 9 through the intermediate formation of N‐(dimethoxymethyl)‐2‐alkynylaniline derivatives II. Compounds 9 could be conveniently converted into N‐unsubstituted indole‐3‐carboxylic esters 10 by a simple acidic treatment carried out in MeOH/H2O at 80 °C.
Hydroxythiazole‐Based Fluorescent Probes for Fluoride Ion Detection
Authors: Calderón‐Ortiz Lorena K. , Täuscher Eric , Leite Bastos Erick , Görls Helmar , Weiß Dieter , Beckert Rainer 
Published: March 2012

AbstractThis work describes the synthesis of five O‐silyloxy‐1,3‐thiazoles and their use as fast‐response “turn‐on” probes for fluoride ion detection in polar aprotic solvents and in aqueous cetyltrimethylammonium bromide micellar medium. The fluoride‐triggered deprotection of these silyl ethers results in ca. 180‐nm shifts in the fluorescence emission wavelengths. All compounds are suitable for the detection of fluoride ions with a detection limit in DMSO of 10–7 mol L–1; derivatives containing a 2‐pyridyl moiety in the thiazole system are more efficient than those with a 3‐ or 4‐pyridyl moiety. Typical anionic interferents, such as acetate or chloride, are not detected by O‐silyloxy‐1,3‐thiazoles, making these compounds very specific for fluoride.
Intermolecular Metal‐Free Cyclopropanation of Alkenes Using Tosylhydrazones
Authors: Barluenga José , Quiñones Noelia , Tomás‐Gamasa María , Cabal María‐Paz 
Published: March 2012

AbstractWe describe the first general method for the metal‐free cyclopropanation of alkenes by using N‐tosylhydrazones as an in situ source of diazo compounds. This new method works with a wide variety of alkenes (styrene derivatives, dienes, enynes, and electron‐deficient alkenes) by using N‐tosylhydrazones derived from various ketones or aldehydes (aromatic, aliphatic, enones). The reaction is performed with the use of K2CO3 as a base to form the diazo species and is compatible with a wide array of functional groups.
Acceptance limits for performance‐based seismic design of RC walls for low‐rise housing
Authors: Carrillo Julian , Alcocer Sergio M. 
Published: March 2012

SUMMARYAcceptance limits of the structural response of walls for low‐rise concrete housing were developed. Proposed values are applicable within a performance‐based seismic design framework. Acceptance limits are based on performance indicators of structural response–allowable story drift ratios, width of residual cracks and residual damage index, and expected damage of walls. Cracking limits were defined from parameters obtained at the unloading stage of walls (i.e., residual cracking stage). The residual cracking stage may be used for structural damage evaluation and cost estimation of structural rehabilitation after an earthquake has occurred. The performance indicators proposed herein were derived from test observations and measured response of 39 RC walls' specimens during shaking table and quasistatic testing, as well as from limiting values and results of previous studies. Copyright © 2012 John Wiley & Sons, Ltd.
Performance Comparison of Pt1–xPdx/Carbon Nanotubes Catalysts in Both Electrodes of Polymer Electrolyte Membrane Fuel Cells
Authors: Jung D.‐W. , Park S. , Ahn C.‐Y. , Kim J.‐B. , Oh E.‐S. 
Published: March 2012

AbstractThe catalytic activity of Pt1–xPdx nanoparticles supported on carbon nanotubes (CNTs) was evaluated for both the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) of polymer electrolyte membrane fuel cells (PEMFCs). Using a colloidal method, Pt1–xPdx/CNTs catalysts (x = 0, 0.46, 0.76, and 0.9) were prepared, and their physical and electrochemical characteristics were analyzed using a variety of characterization techniques, including XRD, TEM, energy dispersive spectrometer, cyclic voltammetry, and electrochemical impedance spectroscopy. Both Pt and Pd atoms formed a continuous solid solution and thus were randomly mixed in Pt1–xPdx nanoparticles. Due to the high hydrogen absorption of Pd, the use of Pd in the catalyst provided an advantage for HOR but a disadvantage for ORR. The Pt0.53Pd0.47/CNTs catalyst in the anode and cathode showed the best cell performance of PEMFCs.
Understanding Membrane Failure in PEMFC: Comparison of Diagnostic Tools at Different Observation Scales
Authors: De Moor G. , Bas C. , Charvin N. , Moukheiber E. , Niepceron F. , Breilly N. , André J. , Rossinot E. , Claude E. , Albérola N. D. , Flandin L. 
Published: March 2012

AbstractPolyelectrolyte membrane used in proton exchange membrane fuel cell (PEMFC) should act as a barrier to hydrogen and electrons. In the present work, fast and robust specific tools were developed both to characterize these properties and localize defects, such as pinholes or short‐circuits, within the membrane electrode assembly (MEA). The identification of defective cells without disassembling the Axane's stack was performed in a single step through a passive electrical technique so‐called “relaxometry” and by internal gas leak measurements. The flaws were further tracked inside MEA using Infrared Thermography in order to obtain their precise location. The latter, performed after stack disassembly, permitted to reveal the defects responsible for the Fuel Cell shutdown. A third step dealt with SEM examinations of the flaws in order to identify the origin and nature of the membrane failure.
Aquaporin‐4 regulates extracellular space volume dynamics during high‐frequency synaptic stimulation: A gene deletion study in mouse hippocampus
Authors: Haj‐Yasein Nadia Nabil , Jensen Vidar , Østby Ivar , Omholt Stig W. , Voipio Juha , Kaila Kai , Ottersen Ole P. , Hvalby Øivind , Nagelhus Erlend A. 
Published: March 2012

AbstractLittle is known about the physiological roles of aquaporin‐4 (AQP4) in the central nervous system. AQP4 water channels are concentrated in endfeet membranes of astrocytes but also localize to the fine astrocytic processes that abut central synapses. Based on its pattern of expression, we predicted that AQP4 could be involved in controlling water fluxes and changes in extracellular space (ECS) volume that are associated with activation of excitatory pathways. Here, we show that deletion of Aqp4 accentuated the shrinkage of the ECS that occurred in the mouse hippocampal CA1 region during activation of Schaffer collateral/commissural fibers. This effect was found in the stratum radiatum (where perisynaptic astrocytic processes abound) but not in the pyramidal cell layer (where astrocytic processes constitute but a minor volume fraction). For both genotypes the ECS shrinkage was most pronounced in the pyramidal cell layer. Our data attribute a physiological role to AQP4 and indicate that this water channel regulates extracellular volume dynamics in the mammalian brain. © 2012 Wiley Periodicals, Inc.