bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Ever‐Surprising Chemistry of Boron: Enhanced Acidity of Phosphine⋅Boranes
Authors: Hurtado Marcela , Yánez Manuel , Herrero Rebeca , Guerrero Andrés , Dávalos Juan Z. , Abboud José‐Luis M. , Khater Brahim , Guillemin Jean‐Claude 
Published: March 2009

AbstractThe acidity‐enhancing effectof BH3in gas‐phase phosphine⋅boranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas‐phase acidities (GA) of MePH2and MePH2⋅BH3differ by about 118 kJ mol−1(see picture).magnified imageThe gas‐phase acidity of a series of phosphines and their corresponding phosphine⋅borane derivatives was measured by FT‐ICR techniques. BH3attachment leads to a substantial increase of the intrinsic acidity of the system (from 80 to 110 kJ mol−1). This acidity‐enhancing effect of BH3is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. This indicates that the enhancement of the acidity of protic acids by Lewis acids usually observed in solution also occurs in the gas phase. High‐level DFT calculations reveal that this acidity enhancement is essentially due to stronger stabilization of the anion with respect to the neutral species on BH3association, due to a stronger electron donor ability of P in the anion and better dispersion of the negative charge in the system when the BH3group is present. Our study also shows that deprotonation of ClCH2PH2and ClCH2PH2⋅BH3is followed by chloride departure. For the latter compound deprotonation at the BH3group is found to be more favorable than PH2deprotonation, and the subsequent loss of Cl−is kinetically favored with respect to loss of Cl−in a typical SN2 process. Hence, ClCH2PH2⋅BH3is the only phosphine⋅borane adduct included in this study which behaves as a boron acid rather than as a phosphorus acid.
An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions
Authors: Yoon Jung Hee , Ryu Dae Won , Kim Hyoung Chan , Yoon Sung Won , Suh Byoung Jin , Hong Chang Seop 
Published: March 2009

AbstractTwo‐step magnetic transitions: An azide‐bridged 1D MnIII coordination polymer with a unique single end‐on mode was prepared; it displayed atypical antiferromagnetic couplings and field‐induced two‐step magnetic transitions (see figure). The spin‐canted phenomenon in the antiferromagnetic chain complex plays a pivotal role in establishing the slow magnetic relaxation.magnified image
Changes in somatodendritic morphometry of rat oculomotor nucleus motoneurons during postnatal development
Authors: Carrascal Livia , Nieto‐Gonzalez Jose Luis , Torres Blas , Nunez‐Abades Pedro 
Published: March 2009

AbstractThis work investigates the somatodendritic shaping of rat oculomotor nucleus motoneurons (Mns) during postnatal development. The Mns were functionally identified in slice preparation, intracellularly injected with neurobiotin, and three‐dimensionally reconstructed. Most of the Mns (∼85%) were multipolar and the rest (∼15%) bipolar. Forty multipolar Mns were studied and grouped as follows: 1–5, 6–10, 11–15, and 21–30 postnatal days. Two phases were distinguished during postnatal development (P1–P10 and P11–P30). During the first phase, there was a progressive increase in the dendritic complexity; e.g., the number of terminals per neuron increased from 26.3 (P1–P5) to 47.7 (P6–P10) and membrane somatodendritic area from 11,289.9 μm2 (P1–P5) to 19,235.8 μm2 (P6–P10). In addition, a few cases of tracer coupling were observed. During the second phase, dendritic elongation took place; e.g., the maximum dendritic length increased from 486.7 μm (P6–P10) to 729.5 μm in adult Mns, with a simplification of dendritic complexity to values near those for the newborn, and a slow, progressive increase in membrane area from 19,235.8 μm2 (P6–P10) to 24,700.3 μm2 (P21–P30), while the somatic area remained constant. In conclusion, the electrophysiological changes reported in these Mns with maturation (Carrascal et al. [2006] Neuroscience 140:1223–1237) cannot be fully explained by morphometric variations; the dendritic elongation and increase in dendritic area are features shared with other pools of Mns, whereas changes in dendritic complexity depend on each population; the first phase paralleled the establishment of vestibular circuitry and the second paralleled eyelid opening. J. Comp. Neurol. 514:189–202, 2009. © 2009 Wiley‐Liss, Inc.
Developmental origins of mosaic brain evolution: Morphometric analysis of the developing zebra finch brain
Authors: Charvet Christine J. , Striedter Georg F. 
Published: March 2009

AbstractIn adult zebra finches (Taeniopygia guttata), the telencephalon occupies 64% of the entire brain. This fraction is similar to what is seen in parrots, but many other birds possess a significantly smaller telencephalon. The aim of the present study was to determine the developmental time course and cellular basis of telencephalic enlargement in zebra finches, and then to compare these findings with what is known about telencephalic enlargement in other birds. To this end we estimated the volumes of all major brain regions from serial sections in embryonic and post‐hatching zebra finches. We also labeled proliferating cells with antibodies against proliferating cell nuclear antigen and phosphorylated histone H3. An important finding to emerge from this work is that the telencephalon of zebra finches at hatching contains a thick proliferative subventricular zone (SVZ) that extends from the subpallium into the dorsal pallium. The data also show that the onset and offset of telencephalic neurogenesis are both delayed in zebra finches relative to quail (Galliformes). This delay in neurogenesis, in conjunction with the expanded SVZ, probably accounts for most of the telencephalic enlargement in passerines such as the zebra finch. In addition, passerines enlarged their telencephalon by decreasing the proportional size of their midbrain tectum. Because the presumptive tectum is proportionally smaller in zebra finches than quail before neurogenesis begins, this difference in tectum size cannot be due to evolutionary alterations in neurogenesis timing. Collectively these findings indicate that several different developmental mechanisms underlie the evolution of a large telencephalon in passerines. J. Comp. Neurol. 514:203–213, 2009. © 2009 Wiley‐Liss, Inc.
Monocyte‐derived macrophage microparticles impart tissue factor activity to biomaterial surfaces
Authors: Patchipulusu Sirisha , Turturro Michael , Hall Connie L. 
Published: March 2009

AbstractThe initiation of coagulation on biomaterials is attributed to the contact pathway of coagulation. However, recent discoveries of blood‐borne tissue factor (TF) activity suggest that the TF pathway of coagulation may contribute to thrombosis on biomaterials. To evaluate the role of TF bearing microparticles to biomaterial thrombogenicity, the adhesion of monocyte‐derived macrophage microparticles (MMPs) to bare, bovine serum albumin (BSA) blocked, and plasma‐coated materials was examined. MMP suspensions consisted of 20–37% TF positive particles that exhibited TF activity. Data from static experiments with polyethylene (PE), polydimethylsiloxane (PDMS), polystyrene (PS), and glass knitted and woven Dacron® grafts showed that MMPs adhered to uncoated, and plasma coated surfaces supported TF activity, whereas surfaces blocked with BSA supported less activity. Flow studies were performed on plasma‐coated glass and tissue culture‐treated polystyrene (TCPS) as a model system to demonstrate deposition and firm adhesion of microparticles under physiologic flow conditions. MMPs deposited and imparted TF activity to plasma‐coated glass at wall shear rates of 100, 400, and 1200 sec−1. Deposition on TCPS was comparable to glass at 100 sec−1, but virtually nonexistent at the two higher shear rates after a 1 h perfusion, implying material and shear dependent adhesion. The localization of procoagulant MMPs to biomaterial surfaces could lead to an increased risk of thrombosis on cardiovascular implants beyond that anticipated by the contact pathway alone. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
In vivo and in vitro characterization of poly(styrene‐b‐isobutylene‐b‐styrene) copolymer stent coatings for biostability, vascular compatibility and mechanical integrity
Authors: Strickler Fred , Richard Robert , McFadden Sharon , Lindquist Jeff , Schwarz Marlene C. , Faust Rudolf , Wilson Gregory J. , Boden Mark 
Published: March 2009

AbstractThe TAXUS® Express 2™Paclitaxel Eluting Coronary Stent System employs a coating consisting of the thermoplastic elastomer, poly(styrene‐b‐isobutylene‐b‐styrene; SIBS), selected for its drug‐eluting characteristics, vascular compatibility, mechanical properties, and biostability. This study was conducted to evaluate the impact of different SIBS (17−51 mole % styrene) compositions on mechanical properties, chemical stability, and vascular compatibility. Mechanical property (stress−strain measurements) and stability studies were conducted on polymer films with five different styrene contents (17, 24, 32, 39, and 51 mole %). The ultimate tensile strength did not change significantly with composition, but the elongation at break decreased with increased styrene content. A pulsatile fatigue test further confirmed the mechanical stability of SIBS up to 39 mole % styrene. The vascular compatibility of five different SIBS compositions was assessed using SIBS‐only coated stents, in the coronary and carotid arteries in a porcine model study. The stability of the vessel wall, rate/degree of endothelialization, inflammation, and thrombus at timepoints from 30 to 180 days were evaluated. The results confirm vascular compatibility over the range of 17−51 mole % styrene. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Synthesis and characterization of a novel in situ forming gel based on hydrogel dispersions
Authors: Wu Jun Jim , Shek Pang N. 
Published: March 2009

AbstractThis report describes the synthesis and characterization of hydrogel dispersions for the potential use as an in situ gel‐forming wound sealant. A series of polyacrylamide (PAAm) particles (solid content 5–10 wt %) were prepared by dispersion polymerization of acrylamide (AAm) in a solvent mixture of ethanol/water (90/10 w/w). These particles are characterized by the presence of a “core” [ethylene glycol dimethacrylate (EGDMA) crosslinked PAAm] surrounded by a “shell” [acetoacetoxyethyl methacrylate (AAEMA) or 2‐aminoethylmethacrylate‐containing PAAm, named as AAEMA‐xPAAm and NH2‐xPAAm, respectively; x represents “crosslinked”]. Two “2‐in‐1” working systems were prepared: (1) AAEMA‐xPAAm mixed with NH2‐xPAAm and (2) AAEMA‐xPAAm mixed with 1,6‐diaminohexane [AAEMA:NH2 (1:1 mol/mol in (1) and (2)]. These systems appeared to possess essential characteristics for their potential use as wound sealants. For example, at 37°C (and/or room temperature), both systems (1) and (2) formed transparent films, within 2 min upon applying them to a substrate; a rapid, concomitant crosslinking reaction occurred between AAEMA and –NH2 on their outer “shells,” knitting the EGDMA‐crosslinked PAAm micro‐“gel” together into a macro one. In contrast to other reported wound sealants, which are in either solution form or powder form, the advantages of hydrogel dispersion‐based sealant may include ease of application (sprayable due to its low viscosity), species encapsulation and protection, and so forth. To our best knowledge, this is the first report on designing a wound sealant based on micro‐particle dispersions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Characterization of the behavior of porous hydrogels in model osmotically‐conditioned articular cartilage systems
Authors: Spiller Kara L. , Laurencin Samuel J. , Lowman Anthony M. 
Published: March 2009

AbstractThe evaluation of hydrogel swelling behavior is a vital step in development of new materials for biomedical applications. Phosphate‐buffered saline (PBS) is the most commonly chosen swelling medium to model hydrogel behavior in articular cartilage (AC). However, the use of PBS does not fully elucidate the osmotic pressure hydrogels will face in many tissues in vivo. Thus, there is a critical need to assess the performance of hydrogels in a model system that can better reflect the native tissues for a specified application. The aim of this study was to evaluate the mechanical properties, porosity, and swelling behavior of poly(vinyl alcohol) hydrogels with a degradable poly(lactic‐co‐glycolic acid) (PLGA) phase in synthetic models and in ex vivo AC model systems. The controlled degradation of the PLGA phase reflected the dynamic nature of native tissues and allowed for the assessment of hydrogel swelling characteristics under fluctuating osmotic pressures. When hydrogels were implanted ex vivo into bovine AC, their swelling ratios and water contents significantly decreased. This response was matched by hydrogels immersed in a solution of PEG having an osmotic pressure matching AC. The hydrogels were further characterized over 6 weeks in PEG and in PBS, with each system having unique affects on the hydrogel swelling behavior and material properties. The results show that a PEG solution conditioned to an osmotic pressure of AC is a strong model for the effects of the osmotic environment on hydrogels and that PBS is an ineffective predictor of swelling changes in vivo. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Dwindling forest resources and economic vulnerability among tribal communities in a dry/ sub‐humid region in India
Authors: Shah Amita , O.G. Sajitha 
Published: March 2009

AbstractThe paper examines livelihood conditions and explores policy options for mitigating poverty among tribal communities in Gujarat state, which is experiencing rapid economic growth and widening disparities where tribals are the most poor and deprived. While labour force diversification and migration are important coping mechanisms, these alone may not help lift a large number of the poor out of the poverty trap, which to a large extent is linked to degradation and lack of proper entitlement for managing and using forest resources among these communities. Forest‐based livelihood options assume special significance especially in the wake of the emerging policy framework for adaptation and mitigation of climate change, where the main thrust could be on combining regeneration and conservation of forests with right kind of incentives for ensuring sustainable management and use of forest resources within the region. The mechanism of ‘compensated conservation’ proposed by India could prove very useful in this context. Copyright © 2009 John Wiley & Sons, Ltd.
Myoanatomy of the marine tardigrade Halobiotus crispae (Eutardigrada: Hypsibiidae)
Authors: Halberg Kenneth Agerlin , Persson Dennis , Møbjerg Nadja , Wanninger Andreas , Kristensen Reinhardt Møbjerg 
Published: March 2009

AbstractThe muscular architecture of Halobiotus crispae (Eutardigrada: Hypsibiidae) was examined by means of fluorescent‐coupled phalloidin in combination with confocal laser scanning microscopy and computer‐aided three‐dimensional reconstruction, in addition to light microscopy (Nomarski), scanning electron microscopy, and transmission electron microscopy (TEM). The somatic musculature of H. crispae is composed of structurally independent muscle fibers, which can be divided into a dorsal, ventral, dorsoventral, and a lateral musculature. Moreover, a distinct leg musculature is found. The number and arrangement of muscles differ in each leg. Noticeably, the fourth leg contains much fewer muscles when compared with the other legs. Buccopharyngeal musculature (myoepithelial muscles), intestinal musculature, and cloacal musculature comprise the animal's visceral musculature. TEM of stylet and leg musculature revealed ultrastructural similarities between these two muscle groups. Furthermore, microtubules are found in the epidermal cells of both leg and stylet muscle attachments. This would indicate that the stylet and stylet glands are homologues to the claw and claw glands, respectively. When comparing with previously published data on both heterotardigrade and eutardigrade species, it becomes obvious that eutardigrades possess very similar numbers and arrangement of muscles, yet differ in a number of significant details of their myoanatomy. This study establishes a morphological framework for the use of muscular architecture in elucidating tardigrade phylogeny. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.
Phase Biaxility in Smectic‐A Side‐Chain Liquid Crystalline Elastomers
Authors: Storz Rebekka , Komp Ansgar , Hoffmann Anke , Finkelmann Heino 
Published: March 2009

Abstract2H NMR investigations on the biaxial phase behavior of smectic‐A liquid crystalline side‐chain elastomers are presented. Biaxiality parameters were determined by measuring the quadrupolar splitting of two spin probes, namely benzene‐d6 and hexamethylbenzene‐d18, at various angles between the principal director and the external magnetic field: while for a uniaxial sample the angular dependence can be described by the second Legendre polynomial, an additional asymmetric term needs to be included to fit the data of the two investigated biaxial systems. Two elastomers synthesized from mesogens that differ in the molecular geometry in order to study the molecular origin of biaxiality were compared. Biaxiality is observed for both elastomers when approaching the glass transition, suggesting that the network dynamics dominate the formation of the biaxial phase.magnified image
Potential role of cytochrome P450‐1B1 in the metabolic activation of 4‐aminobiphenyl in humans
Authors: Ketelslegers Hans B , Godschalk Roger WL , Eskens Bart JM , Dallinga Jan W , Gottschalk Ralph W.H. , van Schooten Frederik J. , van Delft Joost H.M. , Kleinjans Jos C.S. 
Published: March 2009

AbstractMetabolites of the human carcinogen 4‐aminobiphenyl (4‐ABP) form hemoglobin (Hb) adducts, which represent a useful biomarker for exposure. However, not every individual responds to a similar degree to 4‐ABP exposure, and variations in 4‐ABP‐Hb adduct formation might be explained by genetic polymorphisms in genes coding for enzymes involved in 4‐ABP metabolism. 4‐ABP‐Hb adducts were measured in blood samples from 57 smoking and 10 non‐smoking volunteers. An association was found between cigarette smoking and 4‐ABP‐Hb adduct levels in smokers (R2 = 0.5, P < 0.001). Subsequently, subjects were genotyped for 12 polymorphisms in seven genes involved in biotransformation reactions. From this selection of polymorphisms, a significant impact was found for the CYP1B1 Leu432Val polymorphism (P = 0.021), which has been reported to lead to a decrease in enzyme activity. Indeed higher levels of 4‐ABP‐Hb adducts were observed in homo‐ and heterozygous carriers of the CYP1B1 432Leu as compared to the double CYP1B1 432Val genotype. A significant interaction between these CYP1B1 genotypes and the level of exposure was found (P = 0.003). Noteworthy, a saturation effect was observed for 4‐ABP‐Hb adduct formation at high smoking doses limited to carriers of the CYP1B1 432Leu allele. No effect of polymorphisms in other genes were found. This is the first study in humans suggesting a crucial role of the CYP1B1 enzyme in 4‐ABP metabolism, indicating a protective effect of the CYP1B1 Leu432Val polymorphism against the formation of 4‐ABP‐Hb adduct levels, depending on the smoking dose. © 2009 Wiley‐Liss, Inc.
Monitoring of Emulsion Polymerisation Processes using Ion Mobility Spectrometry—A Pilot Study
Authors: Vautz Wolfgang , Mauntz Wolfgang , Engell Sebastian , Baumbach Jörg Ingo 
Published: March 2009

AbstractOnline monitoring of monomer concentrations in (semi‐) batch emulsion polymerisation reactors is important for safe and cost‐efficient operation of production plants. In the present pilot study, ion mobility spectrometry was applied for monitoring the concentration during emulsion polymerisation of vinyl acetate (VA) using UV light for ionisation of the headspace of a continuous sample flow. Satisfactory sensitivity for online process monitoring of the monomer concentration in the reactor was observed (LOD 400 ng · L−1 air, equivalent to <1%). Furthermore, it is possible to discriminate between VA and other common monomers [butyl acrylate (BA), methyl methacrylate (MMA)]. Using the more efficient β‐radiation ionisation, monomer concentration could be measured even in the final latex as a measure of the final product properties.magnified image
Immunological microenvironment in prostate cancer: High mast cell densities are associated with favorable tumor characteristics and good prognosis
Authors: Fleischmann Achim , Schlomm Thorsten , Köllermann Jens , Sekulic Nikolina , Huland Hartwig , Mirlacher Martina , Sauter Guido , Simon Ronald , Erbersdobler Andreas 
Published: March 2009

AbstractBACKGROUNDNumber of intratumoral mast cells predicts survival in various cancers. The prognostic significance of such mast cells in surgically treated prostate cancer is unknown.METHODSMast cell densities were determined in prostate cancer samples of more than 2,300 hormone‐naïve patients using a tissue microarray format in correlation with clinical follow‐up data. Mast cells were visualized immunohistochemically (c‐kit). All patients were homogeneously treated by radical prostatectomy at a single institution.RESULTSMast cells were present in 95.9% of the tumor samples. Median mast cell number on the tissue spot was 9 (range: 0–90; median density: 31 mast cells/mm2). High mast cell densities were significantly associated with more favorable tumors having lower preoperative prostate‐specific antigen (P = 0.0021), Gleason score (P < 0.0001) and tumor stage (P < 0.0001) than tumors with low mast cell densities. Prostate‐specific antigen recurrence‐free survival significantly (P = 0.0001) decreased with decline of mast cell density showing poorest outcome for patients without intratumoral mast cells. In multivariate analysis mast cell density narrowly missed to add independent prognostic information (P = 0.0815) for prostate‐specific antigen recurrence.CONCLUSIONHigh intratumoral mast cell density is associated with favorable tumor characteristics and good prognosis in prostate cancer. This finding is consistent with a role of mast cells in the immunological host‐defense reaction on prostate cancer. Triggering mast cell activity might expand immunotherapeutic strategies in prostate cancer. Prostate 69: 976–981, 2009. © 2009 Wiley‐Liss, Inc.
Kesterite absorber layer uniformity from electrodeposited pre‐cursors
Authors: Kurihara Masato , Berg Dominik , Fischer Johannes , Siebentritt Susanne , Dale Phillip J. 
Published: March 2009

AbstractSpatially resolved measurements of kesterite absorber layer uniformity were made using single wavelength photocurrent and energy dispersive X‐ray (EDX) measurements. The p‐type kesterite absorber layers consisting nominally of Cu2ZnSnS4 (CZTS) were synthesised by sequentially electrodepositing layers of Cu, Sn, and Zn from unstirred baths and subsequently annealing the stacked pre‐cursors in a sulphur containing atmosphere. The photocurrent and EDX measurements showed the samples to have deviations in their photo‐response, thickness, and composition over a scale of a few millimetres. The deviations were shown to be due to the uncontrolled mass transport of the depositing ions on to the Mo substrate surface. When the mass transport was controlled pre‐cursors of uniform thickness and annealed kesterites with uniform composition resulted. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)