bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential responses of sensory neurones innervating glycolytic and oxidative muscle to protons and capsaicin
Authors: Xing Jihong , Sinoway Lawrence , Li Jianhua
Published: May 2008

Activation of thin fibre muscle afferent nerves by metabolic by‐products plays a critical role in the initiation and maintenance of the autonomic response to exercise and the metabolic profile of active muscle can influence the response. The purpose of this report was to determine the responsiveness of sensory neurones innervating muscles comprising predominantly glycolytic and oxidative fibres to protons and capsaicin using whole‐cell patch clamp methods. Dorsal root ganglion (DRG) neurones from 4‐ to 6‐week‐old rats were labelled by injecting the fluorescence tracer DiI into the muscle 3–5 days prior to the recording experiments. The percentage of the DRG neurones innervating glycolytic and oxidative muscle was similar in response to both protons and capsaicin. However, the neurones innervating glycolytic muscle had greater inward current amplitude responses to protons and capsaicin as compared with oxidative muscle. The peak current amplitudes to pH 6.0 were 0.84 ± 0.06 nA (oxidative muscle) versus 1.36 ± 0.07 nA (glycolytic muscle, P < 0.05). The capsaicin‐induced current amplitudes were 2.3 ± 0.15 nA (oxidative muscle) versus 3.1 ± 0.21 nA (glycolytic muscle, P < 0.05). Of neurones that responded to pH 6.0 with a sustained current, 88% also responded to capsaicin. Capsaicin exposure enhanced the proton responsiveness in the neurones innervating the muscle; and protons also increased the capsaicin response. These data suggest that (1) receptors mediating protons and capsaicin responses coexist in the DRG neurones innervating muscle; (2) the responsiveness of acidosis and capsaicin can be sensitized by each other; and (3) DRG neurones with nerve endings in a glycolytic muscle developed greater inward current responses to protons and capsaicin than did those with nerve endings in an oxidative muscle.
Purification and Characterization of a Novel Recombinant Highly Enantioselective Short-Chain NAD(H)-Dependent Alcohol Dehydrogenase from
Thermus thermophilus
Authors: Pennacchio Angela , Pucci Biagio , Secundo Francesco , La Cara Francesco , Rossi Mosè , Raia Carlo A.
Published: May 2008

The gene encoding a novel alcohol dehydrogenase (ADH) that belongs to the short-chain dehydrogenase/reductase (SDR) superfamily was identified in the extremely thermophilic, halotolerant gram-negative eubacterium
Thermus thermophilus
HB27. The
T. thermophilus
ADH gene (
adh
Tt
) was heterologously overexpressed in
Escherichia coli
, and the protein (ADH
Tt
) was purified to homogeneity and characterized. ADH
Tt
is a tetrameric enzyme consisting of identical 26,961-Da subunits composed of 256 amino acids. The enzyme has remarkable thermophilicity and thermal stability, displaying activity at temperatures up to ∼73°C and a 30-min half-inactivation temperature of ∼90°C, as well as good tolerance to common organic solvents. ADH
Tt
has a strict requirement for NAD(H) as the coenzyme, a preference for reduction of aromatic ketones and α-keto esters, and poor activity on aromatic alcohols and aldehydes. This thermophilic enzyme catalyzes the following reactions with Prelog specificity: the reduction of acetophenone, 2,2,2-trifluoroacetophenone, α-tetralone, and α-methyl and α-ethyl benzoylformates to (
S
)-(−)-1-phenylethanol (>99% enantiomeric excess [ee]), (
R
)-α-(trifluoromethyl)benzyl alcohol (93% ee), (
S
)-α-tetralol (>99% ee), methyl (
R
)-(−)-mandelate (92% ee), and ethyl (
R
)-(−)-mandelate (95% ee), respectively, by way of an efficient in situ NADH-recycling system involving 2-propanol and a second thermophilic ADH. This study further supports the critical role of the D37 residue in discriminating NAD(H) from NADP(H) in members of the SDR superfamily.
WolbachiaInfection Alters Olfactory-Cued Locomotion inDrosophilaspp
Authors: Peng Yu , Nielsen John E. , Cunningham J. Paul , McGraw Elizabeth A.
Published: May 2008

Wolbachia pipientisis an endosymbiotic bacterium present in diverse insect species. Although it is well studied for its dramatic effects on host reproductive biology, little is known about its effects on other aspects of host biology, despite its presence in a wide array of host tissues. This study examined the effects of threeWolbachiastrains on two differentDrosophilaspecies, using a laboratory performance assay for insect locomotion in response to olfactory cues. The results demonstrate thatWolbachiainfection can have significant effects on host responsiveness that vary with respect to theWolbachiastrain-host species combination. ThewRi strain, native toDrosophila simulans, increases the basal activity level of the host insect as well as its responsiveness to food cues. In contrast, thewMel strain and the virulentwMelPop strain, native toDrosophila melanogaster, cause slight decreases in responsiveness to food cues but do not alter basal activity levels in the host. Surprisingly, the virulentwMelPop strain has very little impact on host responsiveness inD. simulans. This novel strain-host relationship was artificially created previously by transinfection. These findings have implications for understanding the evolution and spread ofWolbachiainfections in wild populations and forWolbachia-based vector-borne disease control strategies currently being developed.
Identification of thel,d-Transpeptidases for Peptidoglycan Cross-Linking inEscherichia coli
Authors: Magnet Sophie , Dubost Lionel , Marie Arul , Arthur Michel , Gutmann Laurent
Published: May 2008

Three active-site cysteinel,d-transpeptidases can individually anchor the Braun lipoprotein to theEscherichia colipeptidoglycan. We show here that two additional enzymes of the same family form peptide bonds between the third residues of peptidoglycan stems, generatingmeso-DAP3→meso-DAP3unusual cross-links. This activity partially replaces thed,d-transpeptidase activity of penicillin-binding proteins.
Two-State Allosteric Modeling Suggests Protein Equilibrium as an Integral Component for Cyclic AMP (cAMP) Specificity in the cAMP Receptor Protein ofEscherichia coli
Authors: Youn Hwan , Koh Junseock , Roberts Gary P.
Published: May 2008

Activation of the cAMP receptor protein (CRP) fromEscherichia coliis highly specific to its allosteric ligand, cAMP. Ligands such as adenosine and cGMP, which are structurally similar to cAMP, fail to activate wild-type CRP. However, several cAMP-independent CRP variants (termed CRP*) exist that can be further activated by both adenosine and cGMP, as well as by cAMP. This has remained a puzzle because the substitutions in many of these CRP* variants lie far from the cAMP-binding pocket (>10 Å) and therefore should not directly affect that pocket. Here we show a surprising similarity in the altered ligand specificity of four CRP* variants with a single substitution in D53S, G141K, A144T, or L148K, and we propose a common basis for this phenomenon. The increased active protein population caused by an equilibrium shift in these variants is hypothesized to preferentially stabilize ligand binding. This explanation is completely consistent with the cAMP specificity in the activation of wild-type CRP. The model also predicts that wild-type CRP should be activated even by the lower-affinity ligand, adenosine, which we experimentally confirmed. The study demonstrates that protein equilibrium is an integral factor for ligand specificity in an allosteric protein, in addition to the direct effects of ligand pocket residues.
Fluid of Hard Spheres with a Modified Dipole: Simulation and Theory
Authors: Jirsák Jan , Nezbeda Ivo
Published: May 2008

A model fluid made up of hard spheres with a modified point dipole, resulting from application of a perturbation theory to general molecular fluids, is studied by both molecular simulations and theory. Molecular simulations at 64 state points have been performed for two different types of modification. Two variants of Rushbrooke's Padé approximant are used to describe the system theoretically. No satisfactory theoretical results are obtained due to tendencies of the modified dipolar systems to form ferroelectric ordering.
Formation of cluster roots in Alnus incana ssp. rugosa and other Alnus species
Authors: Hurd Todd M. , Schwintzer Christa R.
Published: May 2008

Small numbers of cluster roots were found on older roots of Alnus incana ssp. rugosa (speckled alder) shrubs in the field at 2 of 11 sites. Cluster roots also formed infrequently in speckled alder grown hydroponically in complete nutrient solution. No cluster roots formed in solutions lacking P or Fe. Small numbers of cluster roots also formed in Alnus glutinosa grown hydroponically in the presence of P but not in its absence. In contrast, Alnus rubra produced small numbers of cluster roots in the absence of P but not in its presence. No cluster roots formed in Alnus viridis ssp. crispa. Cluster roots are probably not important for nutrient uptake in speckled alder because they form infrequently both in the field and in hydroponic culture. Keywords: Alnus incana ssp. rugosa, Alnus glutinosa, Alnus rubra, Alnus viridis ssp. crispa, cluster roots, proteoid roots.
Grasses of the Canadian Arctic Archipelago: a DELTA database for interactive identification and illustrated information retrieval
Authors: Aiken S. G. , Consaul L. L. , Dallwitz M. J.
Published: May 2008

A comprehensive re-assessment of grasses in the Canadian Arctic Archipelago is presented as an annotated checklist recognizing 49 taxa. Twenty-five names that have been associated with the flora of the islands are excluded. Information was recorded in a DELTA database. For taxa recognized, the following information is included: common name if applicable, place of valid publication, basionyms, limited synonymy, location of type specimens when known and whether we have seen them, 39 vegetative and 60 floral morphological characters, known chromosome number(s), distribution and habitat data, comments in an annotated checklist, and for many taxa, expanded notes conveying additional information. For 37 of the taxa, their usefulness as environmental indicators is recorded. The above information is also available for some of the excluded taxa; for all of them there are notes explaining why the taxon is excluded. The database is illustrated with 46 maps, 17 line drawings of characters useful for identifications, and photographs of 29 type specimens, 19 herbarium specimens, and 58 photographs of plants in their habitats or close up. The data are available as an INTKEY interactive identification and information-retrieval package for MS-Windows, and as natural-language descriptions in four formats: WWW pages, plain text, PostScript, and HP Laserjet files. Keywords: Poaceae, arctic, taxonomy, WWW, Internet, key.
Physical modelling of a dissolved contaminant in an unsaturated sand
Authors: Cooke B. , Mitchell R. J.
Published: May 2008

Computer solutions to the problem of dissolved contaminant movements in saturated soils are readily available. However, for partially saturated soils, extreme nonlinearity of some variables and difficulties in determining values for other variables make computer solutions predicting the movement of dissolved contaminants highly unreliable. Physical modelling in a geotechnical centrifuge is presented as a viable alternative to numerical modelling. Scaling laws for physical modelling are presented in this paper, and dimensional analysis is used to identify potential difficulties in application of model test results to prototype situations. Preliminary results of experimental work are presented. These results indicate that centrifuge modelling may be a viable approach to the evaluation of dissolved contaminant transport in partially saturated soils. Key words: contaminant transport, centrifuge, unsaturated.
Discrete ice lens theory for frost heave in soils
Authors: Nixon J. F. (Derick)
Published: May 2008

The existing segregation potential (SP) method for frost heave prediction in soils is semiempirical in nature and does not explicitly predict the relationship between heave rate, temperature gradient, and other more fundamental soil properties. The SP method assumes that the heave rate is directly related to the temperature gradient at the frost front but acknowledges that the SP parameter is dependent on pressure, suction at the frost front, cooling rate, soil type, and so forth. This paper extends and modifies an approximate analytical technique of Gilpin and accounts for the effects of distributed phase change within the freezing fringe in both the head- and mass-transfer components of the formulation. The approach requires as input a relationship between frozen hydraulic conductivity and temperature and predicts the discrete location of each ice lens within the freezing soil. The solution can be carried out quickly on a microcomputer to obtain the heave, suction at the frost front, ice lens temperature, and other results of interest with time. Furthermore, the discrete ice lens method predicts the effects of changing overburden pressure on the predicted heave rate. A method of extracting input parameters for the discrete ice lens procedure from a series of frost heave tests is proposed. The discrete ice theory has been tested and calibrated against well-documented frost heave test results in the literature, and very encouraging agreement between prediction and observation has been obtained. Key words: frost heave, discrete ice lens, segregation potential, hydraulic conductivity of frozen soil, freezing soil.
A study of particle interaction energies in wetting of unsaturated expensive; clays
Authors: Yong Raymond N. , Mohamed Abdel Mohsen O.
Published: May 2008

The results of infiltration (wetting) experiments conducted on expansive soils demonstrate several requirements and constraints to the techniques used for the study of wetting performance of such soils. In part, these constraints are a necessary outcome of limitations imposed by the difficulties (impossibility?) of measurement of swelling pressure at the wetting front. To provide a better insight into the development of swelling and reaction pressure in the soil during the wetting process, the energies of interaction between particles and water are examined, especially in regard to those forces developed in the Stern layer. The Grahame modification of the Stern layer has been used in this study to provide the basis for calculations of interaction energies in the inner and outer Helmholtz planes. Comparison with high-pressure consolidation of a sodium montmorillonite at very close particle separation distances suggests that the addition of the energies of interaction developed in the Stern layer to the Gouy–Chapman model would permit the double-layer model to be extended to close particle spacings. Whether this is sufficient to account for the stage I wetting process is a question that remains to be further studied. For the present, the test results suggest that the expression for the total soil–water potential ψ should account for those forces of interaction, thereby providing a better account of the physical processes involved in wetting of the expansive clay and a more realistic diffusion coefficient for the total wetting process. Key words : soil-water potential, osmotic potential, swelling pressure, volume change, wetting front, Stern layer, inner Helmholtz plane, outer Helmholtz plane, Coulombic forces, dipole–dipole interaction, ion–dipole interaction.
Water–mineral interaction in hygromechanics of clays exposed to environmental loads: a mixture-theory approach
Authors: Hueckel Tomasz A.
Published: May 2008

Water–mineral interaction in narrow interstices (<30 Å (1 Å = 0.1 nm)) in dense, saturated clays is discussed in view of recent experimental findings and molecular dynamics simulations. Consequences to the macroscopic behavior are considered. A mixture theory for two interacting constituents is developed. Effects of temperature and chemicals are discussed. A postulate of mass transfer of adsorbed water from solid to fluid fraction caused by thermal or chemical load is then discussed. Theory of plasticity of clays affected by heat or chemicals is developed to deal with the effects of thermal and chemical consolidation. Key words : hydraulic conductivity, effective stress, environmental loads, thermo-chemo-plasticity.
Model studies of socketed caissons in soft rock
Authors: Dykeman P , Valsangkar A J
Published: May 2008

Results of centrifuge modelling of socketed caissons in a weak model rock made of cement, sand, bentonite, and water are presented. The model socketed caissons were made from aluminium tubing with a structural stiffness closely identical to a solid concrete pile. In the first series of tests, model sockets were tested in axial compression to determine the effect of socket roughness on side resistance. In the second series, model sockets were subjected to lateral loading. The experimental results are compared with existing design methods used to predict ultimate capacity and load deformation response. Data obtained from other model studies and full-scale tests are also presented and compared with the centrifuge modelling data.

Key words: socketed caissons, centrifuge modelling, weak rock, lateral deformation, axial deformation.
Determination of bentonite content in soilbentonite liners by X-ray diffraction
Authors: Chapuis Robert P , Pouliot Gaston
Published: May 2008

The full-scale hydraulic performance of a soilbentonite liner depends on the homogeneity of bentonite content in the mix; any prediction must consider the distribution function of the local bentonite content, mainly that of below average values. The degree of homogeneity in the field depends on the mixing method and the sand characteristics. Several techniques, such as double hydrometer tests, or methylene blue tests, can evaluate the bentonite content in a sample. They are not reliable when the sand varies in gradation and mineralogy. This led to the investigation of whether X-ray diffraction could determine the bentonite content in a soilbentonite sample and a method was developed. First, the mix must be thermally treated to eliminate the variation in diffraction intensities resulting from the variable hydration of the montmorillonite. Then, an internal standard must be used to control the X-ray absorption. This paper presents the preliminary calibration work, the different steps to follow for quantitative determination of the bentonite content, its accuracy, and its application to a special project where the usual methods were not reliable due to a large variability in sand properties. The parameters needed to calculate the bentonite content in a mix depend on the type of bentonite but not on the type of sand. The accuracy depends on the variability in mineralogical quality of the bentonite powder. For one project, it is shown that the in situ mixing technique produced highly variable local bentonite contents, and that the average content was higher in the lower half of the lift than in its upper half.

Key words: liner, bentonite, control, permeability.
Genetic variation of ecophysiological traits in red alder (Alnusrubra Bong.)
Authors: Dang Q.L. , Xie C.Y. , Ying C. , Guy R.D.
Published: May 2008

We examined the genetic variation of ecophysiological traits within and among 40 red alder (Alnusrubra Bong.) provenances (two families per provenance) in a common-garden experiment in the summer of 1993. The provenances were representative of the entire species range in British Columbia, Canada. We found significant genetic variation among provenances (P < 0.001) in photosynthetic rate (A), mesophyll conductance (gm), transpiration rate (E), stomatal conductance (gsw), stomatal sensitivity to water vapour pressure deficit (SENSVPD), intercellular to ambient CO2 concentration ratio (Ci/Ca), and midday xylem water potential (ψ). Photosynthetic water-use efficiency, however, did not differ significantly among provenances. There were no significant differences between families within provenance for any of these variables. A weak but significant geographic trend was detected in ecophysiological traits: ψ, A, gm, and E increased, and SENSVPD decreased, from southeast to northwest. Photosynthetic rate, E, gm, gsw and ψ were positively related to each other, but negatively correlated with SENSVPD. Ci/Ca was negatively correlated with gsw. These correlations indicate that red alder might have undergone genetic differentiation in drought resistance.
Acid rain and soils of the Adirondacks. II. Evaluation of calcium and aluminum as causes of red spruce decline at Whiteface Mountain, New York
Authors: Johnson A.H. , Schwartzman T.N. , Battles J.J. , Miller R. , Miller E.K. , Friedland A.J. , Vann D.R.
Published: May 2008

not available
ENERGY–MOMENTUM FOR RANDALL–SUNDRUM MODELS
Authors: LIU YU-XIAO , ZHANG LI-JIE , WANG YONG-QIANG , DUAN YI-SHI
Published: May 2008

We investigate the conservation law of energy–momentum for Randall–Sundrum models by the general displacement transform. The energy–momentum current has a superpotential and are therefore identically conserved. It is shown that for Randall–Sundrum solution, the momentum vanishes and most of the bulk energy is localized near the Planck brane. The energy density is ε = ε0e-3k|y|.
WEHRL ENTROPY AND ENTANGLEMENT OF A TIME-DEPENDENT TWO-LEVEL TRAPPED ION INTERACTING WITH A LASER FIELD
Authors: ABDEL-ATY MAHMOUD , ABDEL-KHALEK SAYED , OBADA ABDEL-SHAFY F.
Published: May 2008

The time evolution of the atomic Wehrl entropy and long-lived entanglement generation using a single trapped ion interacting with a laser field are analyzed. Starting from the Heisenberg equation of motion, an exact solution of the system is obtained by indicating that there are some interesting features when a time-dependent modulating function is considered. We demonstrate that the long-living quantum entanglement can be obtained using the time-independent interaction when the field is initially in a pair cat states.
REMOTE FIELD AND ATOMIC STATE PREPARATION
Authors: ISLAM RAMEEZ-UL- , IKRAM MANZOOR , KHOSA ASHFAQ H. , SAIF FARHAN
Published: May 2008

A scheme for remote preparation of field (atomic) states is proposed. Protocol execution requires cavity QED based atom-field interactions successively supplemented with Ramsey interferometry. The state to be remotely prepared at the receiver's end is acquired by deterministically manipulating the sender's component of the pre-shared entangled state. In the case of field entanglement, it is carried out with the help of an atom that passes through the sender's cavity and then traverses a classical external field for specified times prior to detection. However, for atomic entangled states, only interactions with the classical field suffice to complete the task. The scheme guarantees good success probability with high fidelity and requires one bit of classical communication.
ON THE POWER OF QUANTUM TAMPER-PROOF DEVICES
Authors: BOUDA J. , MATEUS P. , PAUNKOVIC N. , RASGA J.
Published: May 2008

We show how quantum tamper-proof devices (QTPD's) can be used to attack and to develop security protocols. On one hand, we prove that it is possible to transfer proofs of zero-knowledge protocols using QTPD's. This attack can be extended to other security schemes where privacy is important. On the other hand, we present a fair contract signing protocol using QTPD's where there is no communication with Judge during the exchange phase (which is impossible classically). In the latter case, we make use of decoherence in the quantum state of the QTPD to implement a global clock over the asynchronous network. QTPD's seem to be possible to implement with existing quantum hardware, due to the fact that it is hard to isolate quantum memory from interference. These theoretical results contribute to justify the implementation of QTPD's.
Arginine therapy of transgenic-knockout sickle mice improves microvascular function by reducing non-nitric oxide vasodilators, hemolysis, and oxidative stress
Authors: Kaul Dhananjay K. , Zhang Xiaoqin , Dasgupta Trisha , Fabry Mary E.
Published: May 2008

In sickle cell disease, nitric oxide (NO) depletion by cell-free plasma hemoglobin and/or oxygen radicals is associated with arginine deficiency, impaired NO bioavailability, and chronic oxidative stress. In transgenic-knockout sickle (BERK) mice that express exclusively human α- and βS-globins, reduced NO bioavailability is associated with induction of non-NO vasodilator enzyme, cyclooxygenase (COX)-2, and impaired NO-mediated vascular reactivity. We hypothesized that enhanced NO bioavailability in sickle mice will abate activity of non-NO vasodilators, improve vascular reactivity, decrease hemolysis, and reduce oxidative stress. Arginine treatment of BERK mice (5% arginine in mouse chow for 15 days) significantly reduced expression of non-NO vasodilators COX-2 and heme oxygenase-1. The decreased COX-2 expression resulted in reduced prostaglandin E2(PGE2) levels. The reduced expression of non-NO vasodilators was associated with significantly decreased arteriolar dilation and markedly improved NO-mediated vascular reactivity. Arginine markedly decreased hemolysis and oxidative stress and enhanced NO bioavailability. Importantly, arteriolar diameter response to a NO donor (sodium nitroprusside) was strongly correlated with hemolytic rate (and nitrotyrosine formation), suggesting that the improved microvascular function was a response to reduced hemolysis. These results provide a strong rationale for therapeutic use of arginine in sickle cell disease and other hemolytic diseases.
The sex-specific impact of systolic hypertension and systolic blood pressure on arterial-ventricular coupling at rest and during exercise
Authors: Chantler Paul D. , Melenovsky Vojtech , Schulman Steven P. , Gerstenblith Gary , Becker Lewis C. , Ferrucci Luigi , Fleg Jerome L. , Lakatta Edward G. , Najjar Samer S.
Published: May 2008

In healthy subjects the arterial system and the left ventricle (LV) are tightly coupled at rest to optimize cardiac performance. Systolic hypertension (SH) is a major risk factor for heart failure and is associated with structural and functional alterations in the arteries and the LV. The effects of SH and resting systolic blood pressure (SBP) on arterial-ventricular coupling ( EaI/ ELVI) at rest, at peak exercise, and during recovery are not well described. We noninvasively characterized EaI/ ELVI as end-systolic volume index/stroke volume index in subjects who were normotensive (NT, n = 203) or had SH (brachial SBP ≥140 mmHg, n = 79). Cardiac volumes were measured at rest and throughout exhaustive upright cycle exercise with gated blood pool scans. EaI/ ELVI reserve was calculated by subtracting peak from resting EaI/ ELVI. At rest, EaI/ ELVI did not differ between SH and NT men but was 23% ( P = 0.001) lower in SH vs. NT women. EaI/ ELVI did not differ between SH and NT men or women at peak exercise or during recovery. Nevertheless, EaI/ ELVI reserve was 61% ( P < 0.001) lower in SH vs. NT women. Similarly, resting SBP (as a continuous variable) was not associated with EaI/ ELVI in men (β = −0.12, P = 0.17) but was inversely associated with EaI/ ELVI in women (β = −0.47, P < 0.001). SH and a higher resting brachial SBP are associated with a lower EaI/ ELVI at rest in women but not in men, and SH women have an attenuated EaI/ ELVI reserve. Whether a smaller EaI/ ELVI reserve leads to functional limitations warrants further examination.
The benefit of medium-chain triglyceride therapy on the cardiac function of SHRs is associated with a reversal of metabolic and signaling alterations
Authors: Iemitsu Motoyuki , Shimojo Nobutake , Maeda Seiji , Irukayama-Tomobe Yoko , Sakai Satoshi , Ohkubo Takeshi , Tanaka Yukihisa , Miyauchi Takashi
Published: May 2008

The spontaneously hypertensive rat (SHR) is a model of cardiomyopathy that displays a genetic defect in cardiac fatty acid (FA) translocase/CD36, a plasma membrane long-chain FA transporter. Therapy with medium-chain FAs, which do not require CD36-facilitated transport, has been shown to improve cardiac function and hypertrophy in SHRs despite persistent hypertension. However, little is known about the underlying molecular mechanisms. The aim of this study was to document the impact of medium-chain triglyceride (MCT) therapy in SHRs on the expression level and activity of metabolic enzymes and signaling pathways. Four-week-old male SHRs were administered MCT (SHR-MCT) or long-chain triglyceride (SHR-LCT) for 16 wk. We used Wistar-Kyoto (WKY) rats as controls (WKY-MCT and WKY-LCT). The SHR-MCT group displayed improved cardiac dysfunction [as assessed by left ventricular (LV) end-diastolic pressure and the positive and negative first derivatives of LV pressure/ P value], a shift in the β-myosin heavy chain (MHC)-to-α-MHC ratio, and cardiac hypertrophy compared with the SHR-LCT group without an effect on blood pressure. Administration of MCT of SHRs reversed the LCT-induced reduction in the cardiac FA metabolic enzymatic activities of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and medium-chain acyl-CoA dehydrogenase (MCAD). In the SHR-MCT group, the protein expression and transcriptional regulation of myocardial peroxisome proliferator-activated receptor-α, which regulates the transcription of LCHAD and MCAD genes, corresponded to the changes seen in those enzymatic activities. Furthermore, MCT intake caused an inhibition of JNK activation in SHR hearts. Collectively, the observed changes in the myocardial activity of metabolic enzymes and signaling pathways may contribute to the improved cardiac dysfunction and hypertrophy in SHRs following MCT therapy.
Vascular oxidative stress and nitric oxide depletion in HIV-1 transgenic rats are reversed by glutathione restoration
Authors: Kline Erik R. , Kleinhenz Dean J. , Liang Bill , Dikalov Sergey , Guidot David M. , Hart C. Michael , Jones Dean P. , Sutliff Roy L.
Published: May 2008

Human immunodeficiency virus (HIV)-infected patients have a higher incidence of oxidative stress, endothelial dysfunction, and cardiovascular disease than uninfected individuals. Recent reports have demonstrated that viral proteins upregulate reactive oxygen species, which may contribute to elevated cardiovascular risk in HIV-1 patients. In this study we employed an HIV-1 transgenic rat model to investigate the physiological effects of viral protein expression on the vasculature. Markers of oxidative stress in wild-type and HIV-1 transgenic rats were measured using electron spin resonance, fluorescence microscopy, and various molecular techniques. Relaxation studies were completed on isolated aortic rings, and mRNA and protein were collected to measure changes in expression of nitric oxide (NO) and superoxide sources. HIV-1 transgenic rats displayed significantly less NO-hemoglobin, serum nitrite, serum S-nitrosothiols, aortic tissue NO, and impaired endothelium-dependent vasorelaxation than wild-type rats. NO reduction was not attributed to differences in endothelial NO synthase (eNOS) protein expression, eNOS-Ser1177phosphorylation, or tetrahydrobiopterin availability. Aortas from HIV-1 transgenic rats had higher levels of superoxide and 3-nitrotyrosine but did not differ in expression of superoxide-generating sources NADPH oxidase or xanthine oxidase. However, transgenic aortas displayed decreased superoxide dismutase and glutathione. Administering the glutathione precursor procysteine decreased superoxide, restored aortic NO levels and NO-hemoglobin, and improved endothelium-dependent relaxation in HIV-1 transgenic rats. These results show that HIV-1 protein expression decreases NO and causes endothelial dysfunction. Diminished antioxidant capacity increases vascular superoxide levels, which reduce NO bioavailability and promote peroxynitrite generation. Restoring glutathione levels reverses HIV-1 protein-mediated effects on superoxide, NO, and vasorelaxation.
Leukocyte antibacterial functions are not impaired by perfluorocarbon exposure in vitro
Authors: Haufe Dirk , Koenigshausen Eva , Knels Lilla , Wendel Martina , Stehr Sebastian N. , Koch Thea
Published: May 2008

Application of liquid, aerosolized, and vaporized perfluorocarbons (PFC) in acute lung injury has shown anti-inflammatory effects. Although this may be beneficial in states of pulmonary hyperinflammation, it also could increase susceptibility to nosocomial lung infection. We hypothesized that PFC impair cellular host defense and therefore investigated in an in vitro model the influence of perfluorohexane (PFH) on crucial mechanisms of bacterial elimination in human neutrophils and monocytes. Using scanning and transmission electron microscopy, we could show membrane-bound and ingested PFH particles that morphologically did not alter adherence and phagocytosis of Escherichia coli or leukocyte viability. The amount of adherent and phagocytosed bacteria as determined by flow cytometry was not influenced in cells only pretreated with PFH for 1 and 4 h. When PFH was present during E. coli challenge, bacterial adherence was decreased in polymorphonuclear neutrophils, but respective intracellular uptake was not impaired and was even significantly promoted in monocytes. Overall, E. coli-induced respiratory burst capacity was not reduced by PFH. Our findings provide evidence that key functions of innate host defense are not compromised by PFH treatment in vitro.
Complete Downmodulation of P-Selectin Glycoprotein Ligand in Monocytes Undergoing Apoptosis
Authors: Stampfuss Jan-Julius , Censarek Petra , Fischer Jens W. , Kaber Gernot , Rauch Bernhard H. , Freidel Kerstin , Fischer Ute , Schulze-Osthoff Klaus , Grosser Tilo , Grandoch Maria , Schrör Karsten , Weber Artur-Aron
Published: May 2008

Objectives—

Apoptotic monocytes release membrane microparticles which may play a major role in thrombogenicity through a P-selectin glycoprotein ligand (PGSL-1)–mediated mechanism. We have studied systematically the regulation of PSGL-1 expression and function in apoptotic monocytic cells.

Methods and Results—

PSGL-1 expression (flow cytometry, immunofluorescence microscopy, immunoblot) was virtually abolished in apoptotic monocytes by proteolytic shedding. This was accompanied by a complete loss of PSGL-1–mediated platelet–leukocyte (flow cytometry) and leukocyte–endothelial cell (parallel plate flow chamber) interactions. Systematic screening of protease inhibitors combined with knock-out and siRNA experiments characterized the PSGL-1-cleaving enzyme as an N-ethylmaleimide-inhibitable metalloproteinase of the ADAM family.

Conclusions—

Downmodulation of PGSL-1 in apoptotic monocytes may prevent ectopic cell clearance in the peripheral vasculature to reduce local inflammatory and proliferative responses. Depletion of PSGL-1 expression on apoptotic microparticles may also act as a molecular switch to modulate their thrombogenic activity.
Discoidin Domain Receptor 1 (
Ddr1
) Deletion Decreases Atherosclerosis by Accelerating Matrix Accumulation and Reducing Inflammation in Low-Density Lipoprotein Receptor–Deficient Mice
Authors: Franco Christopher , Hou Guangpei , Ahmad Pamela J. , Fu Edwin Y.K. , Koh Lena , Vogel Wolfgang F. , Bendeck Michelle P.
Published: May 2008

Collagens are abundant within the atherosclerotic plaque, where they contribute to lesion volume and mechanical stability and influence cell signaling. The discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase that binds to collagen, is expressed in blood vessels, but evidence for a functional role during atherogenesis is incomplete. In the present study, we generated
Ddr1
+/+
;
Ldlr
−/−
and
Ddr1
−/−
;
Ldlr
−/−
mice and fed them an atherogenic diet for 12 or 24 weeks. Targeted deletion of
Ddr1
resulted in a 50% to 60% reduction in atherosclerotic lesion area in the descending aorta at both 12 and 24 weeks.
Ddr1
−/−
;
Ldlr
−/−
plaques exhibited accelerated deposition of fibrillar collagen and elastin at 12 weeks compared with
Ddr1
+/+
;
Ldlr
−/−
plaques. Expression analysis of laser microdissected lesions in vivo, and of
Ddr1
−/−
smooth muscle cells in vitro, revealed increased mRNA levels for procollagen α1(I) and α1(III) and tropoelastin, suggesting an enhancement of matrix synthesis in the absence of DDR1. Furthermore, whereas plaque smooth muscle cell content was unchanged,
Ddr1
−/−
;
Ldlr
−/−
plaques had a 49% decrease in macrophage content at 12 weeks, with a concomitant reduction of in situ gelatinolytic activity. Moreover, mRNA expression of both monocyte chemoattractant protein-1 and vascular cell adhesion molecule-1 was reduced in vivo, and
Ddr1
−/−
;
Ldlr
−/−
macrophages demonstrated impaired matrix metalloproteinase expression in vitro. These data suggest novel roles for DDR1 in macrophage recruitment and invasion during atherogenesis. In conclusion, our data support a role for DDR1 in the regulation of both inflammation and fibrosis early in plaque development. Deletion of DDR1 attenuated atherogenesis and resulted in the formation of matrix-rich plaques.
Endothelial Progenitor Cell Research in Stroke
Authors: Rouhl Rob P.W. , van Oostenbrugge Robert J. , Damoiseaux Jan , Tervaert Jan-Willem Cohen , Lodder Jan
Published: May 2008

Background and Purpose—

Stroke is the leading cause of disability in the Western world; however, few therapies are at hand to decrease this burden.

Summary of Review—

Endothelial progenitor cells (EPCs) have been introduced in cardiovascular medicine as factotums. EPCs can repair damaged endothelium and attenuate the development and progression of atherosclerosis. Also, EPCs can form new vessels in ischemic areas and thus promote recovery after ischemic events. In stroke, however, EPC research is limited. In our overview, we provide background information on EPC use as a risk marker and as a potential therapeutic agent.

Conclusion—

In our opinion, the lack of EPC studies in stroke should instigate vascular neurologists to participate in EPC research, as EPCs could also change pathophysiological concepts and improve clinical treatments in vascular neurology.
Liposome Delivery of Quantum Dots to the Cytosol of Live Cells
Authors: Dudu Veronica , Ramcharan Melissa , Gilchrist M. Lane , Holland Eric C. , Vazquez Maribel
Published: May 2008

An increasing number of studies have demonstrated the multiple advantages of using nanocrystals, such as Quantum dots, for biological imaging. Quantum dots functionalized with biomolecules on their surfaces were shown to be able to bind to specific extracellular targets via specific
recognition and to be internalized inside the cells, thereby allowing the imaging of intracellular pathways. However, the use of Quantum dots for live tracking of intracellular molecules is relatively limited because of the difficulties encountered during the induction of Quantum dots across
living cell membranes. In this study we show that cationic liposomes can deliver low concentrations of non-targeted Quantum dots into the cytosol of living cells via a lipid-mediated fusion with the cell membrane. The intracellular Quantum dots exhibit aggregation that appears dependent upon
their concentration, but does not visibly affect cell viability. Our results point towards the use of cationic liposomes as an effective delivery system for targeted Quantum dots within the cell cytosol, which would facilitate live cell imaging of the labeled molecules.
Carbon Nanotubes Produced from Natural Cellulosic Materials
Authors: Goodell Barry , Xie Xinfeng , Qian Yuhui , Daniel Geoffrey , Peterson Michael , Jellison Jody
Published: May 2008

Carbon nanotubes (CNTs) were produced from wood fiber using a low temperature process, which included continuous oxidization at 240 °C and cyclic oxidation at 400 °C. The inside diameter of the CNTs was approximately 4–5 nm and the outside diameter ranged from 10 nm to
20 nm. No CNTs were produced when pure lignin and cellulose were tested indicating that the molecular and spatial arrangement of cell wall plays an important role in CNT formation. The research suggests that the chemical components in the secondary plant cell wall and their differential ablation
properties are critical for the formation of CNTs at these comparatively low temperatures.
Structural and Mössbauer Effect Investigations of Amorphous FeCuNbSiB Alloys Nanocrystallized (VITROPERM) in Magnetic Field
Authors: Basheed G. A. , Kaul S. N.
Published: May 2008

Melt-spun amorphous ribbons of nominal composition Fe73Cu1Nb3Si16B7, annealed at 560–580 °C for 1 hour in a magnetic field (H) applied along the width in the ribbon plane, develop uniaxial magnetic anisotropy with easy
axis along H and exhibit several novel attributes. The samples labelled as S20 and S150 are nanocomposites consisting of ferromagnetic nanocrystalline grains (volume fraction ≃ 84% and 81%) of mean size d = 13(2) nm embedded in a ferromagnetic amorphous matrix
and possess a magnetic permeability as large as 20,000 and 150,000, respectively. While nearly 55% of the nanocrystalline grains have a cubic DO3Fe3Si-like structure with actual Si concentration of about 22 at.%, the remaining 45% nanocrystalline grains have tetragonal
Fe3B and hexagonal Fe2Si structure. Since the crystalline volume fraction of Fe3B and Fe2Si nanocrystals is more in the sample S20, this sample exhibits stronger local magnetic anisotropy and hence lower permeability.
Photoluminescence of Silica Nanostructures from Bioreactor Culture of Marine Diatom Nitzschia frustulum
Authors: Qin Tian , Gutu Timothy , Jiao Jun , Chang Chih-Hung , Rorrer Gregory L.
Published: May 2008

The marine diatom Nitzschia frustulum is a single-celled photosynthetic organism that uses soluble silicon as the substrate to fabricate intricately patterned silica shells called frustules consisting of 200 nm diameter pores in a rectangular array. Controlled photobioreactor
cultivation of the N. frustulum cell suspension to silicon starvation induced changes in the nanostructure of the diatom frustule, which in turn imparted blue photoluminescence (PL) to the frustule biosilica. The photoluminescent properties were imbedded within a patterned substrate
precisely ordered at the nano, submicron and microscales. The peak PL intensity increased by a factor of 18 from the mid-exponential to late stationary phase of the cultivation cycle, and the peak PL wavelength increased from 440 to 500 nm. TEM analysis revealed that the emergence of blue
photoluminescence was associated with the appearance of fine structures on the frustule surface, including 5 nm nanopore arrays lining the base of the frustule pores, which were only observed at the late stationary phase when both silicon consumption and cell division were complete for two
photoperiods. Photoluminescence was quenched by thermal annealing of diatom biosilica in air at 800 °C for 1.0 hr, commensurate with the loss of silanol (≡Si-OH)groups on the diatom biosilica, as confirmed by FT-IR. Consequently, the likely origin of blue photoluminescence in the
diatom biosilica was from surface silanol groups and their distribution on the frustule fine structures.
New Aspects of Nanopharmaceutical Delivery Systems
Authors: Marcato Priscyla D. , Durán Nelson
Published: May 2008

Nanobiotechnology, involving biological systems manufactured at the molecular level, is a multidisciplinary field that has fostered the development of nanoscaled pharmaceutical delivery devices. Micelles, liposomes, solid lipid nanoparticles, polymeric nanoparticles, functionalized
nanoparticles, nanocrystals, cyclodextrins, dendrimers, nanotubes and metallic nanoparticles have been used as strategies to deliver conventional pharmaceuticals or substances such as peptides, recombinant proteins, vaccines and nucleotides. Nanoparticles and other colloidal pharmaceutical
delivery systems modify many physicochemical properties, thus resulting in changes in the body distribution and other pharmacological processes. These changes can lead to pharmaceutical delivery at specific sites and reduce side effects. Therefore, nanoparticles can improve the therapeutic
efficiency, being excellent carriers for biological molecules, including enzymes, recombinant proteins and nucleic acid. This review discusses different pharmaceutical carrier systems, and their potential and limitations in the field of pharmaceutical technology. Products with these technologies
which have been approved by the FDA in different clinical phases and which are on the market will be also discussed.
Tribological Properties of Single-Walled Carbon Nanotube Solids
Authors: Yamamoto Go , Hashida Toshiyuki , Adachi Koshi , Takagi Toshiyuki
Published: May 2008

Binder-free single-walled carbon nanotube (SWCNT) solids were evaluated for solid lubrication applications. The steady-state friction coefficients (μ) for the SWCNT solids were found to reach values as low as 0.22–0.24, according to unidirectional sliding friction tests
using Si3N4 counterparts in air. The values were slightly higher than that of bulk graphite material (μ = 0 20). SEM and Raman analyses showed that most SWCNTs that existed in the friction surface transformed into SWCNT-derived transferred film made up of amorphous
carbon during sliding. The resultant friction behavior may be related to the smearing of transferred film over the contact area, which was expected to permit easy shear and then help to achieve a lubricating effect during sliding.
Characteristics and Mechanical Properties of Titanium-Containing Diamond Like Carbon Films Deposited by Cathodic Arc Evaporation
Authors: Tsai Pi-Chuen , Chiang Jueh-Yu , Hwang Yen-Fei
Published: May 2008

Depositions of titanium-containing diamond-like carbon (Ti-DLC) films were conducted by mixing C+ and Ti+ plasma streams originated from cathodic arc plasma sources in argon (Ar). The deposition was processed at Ti target current ranging from 20 Amp to 70 Amp.
Film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). Film microstructures were evaluated using field emission scanning electron microscopy (FEGSEM), an atomic force microscope (AFM), X-ray diffractometry (XRD) and high-resolution transmission
electron microscopy (HRTEM). Mechanical properties were investigated by using a nanoindentation tester and ball on disc wear test. Results shows that surface roughness (Ra) of the films ranged between 2.4 and 7.2 nm and roughness increased relative to the increase in Ti target
current. The FESEM studies showed that the surface micrographs of Ti-DLC films revealed a cauliflower-like microstructure and the cross-sectional micrograph revealed a snake-skin like structure. HRTEM studies showed that the Ti-DLC films consisted of nano scale TiC particles which were comparable
with low angle XRD and XPS results. XPS analysis established that the Ti2p spectrum is present when the Ti target current reaches 30 Amp or higher. Ti concentration increased as the Ti target current was increased. An extremely thin TiO2 layer exists on the top of the Ti-DLC films
which was comparable with the AES results. The film thickness which could be deposited for Ti-DLC is much higher than that of conventional DLC films. Nanoindentation tests show that the nanohardness of the films ranging 15–22 GPa, with Er values ranging from 145 to
175 GPa. The wear test demonstrates the friction coefficient of the 420SS substrate, DLC and Ti-DLC films were about 0.8, 0.3 and 0.2, respectively. Obviously, the friction coefficients of the Ti-DLC films were lower than that of the DLC films.