bluuebunny/crossref_metadata_2025 huggingface dataset:
Crown ethers as synergistic agents in the solvent extraction of trivalent lanthanides with 8-hydroxyquinoline
Authors: Atanassova M.
Published: March 2008

The liquid extraction of the 13 lanthanides with mixtures of 8-hydro?xyquinoline (HQ) and crown ethers (S) dibenzo-18-crown-6 (DB18C6) and di?benzo-24-crown-8 (DB24C8) in 1,2-dichloroethane as a diluent from chloride medium at constant ionic strength ? = 0.1 was investigated. The composition of the extracted species was established as LnQ3 with HQ alone and as LnQ3?S in the presence of a crown ether. The values of the equilibrium constants were calculated. The addition of DB18C6 to the metal chelate system improved the extraction efficiency, while a weak synergistic enhancement was found when the metals were extracted with mixtures of HQ-DB24C8. The parameters of the extraction process were determined and the separation factors between two adjacent lanthanides(III) were calculated.
Molecular parameters for the gas phase molecules SbO and SbP
Authors: Ramachandran Sri , Raja V. , Rajamanickam N.
Published: March 2008

Franck-Condon factors and r-centroids, which are very closely related to relative vibrational transition probabilities, were evaluated by the numerical integration procedure for the bands of the A2?3/2 - X2?3/2, C2? - X2?3/2 and D2? - X2? systems of the isotopic SbO molecule and for the B1? - X1?+ system of the isotopic SbP molecule, using a suitable potential.
Characterization studies and cyclic voltammetry on nickel(II) amino acid dithiocarbamates with triphenylphosphine in the coordination sphere
Authors: Geetha Natesan , Thirumaran Subbiah
Published: March 2008

Nickel(II) amino acid dithiocarbamate complexes of the composition [Ni(AAdtc)(PPh3)(NCS)], [Ni(AAdtc)(PPh3)(CN)] and [Ni(AAdtc)(PPh3)2]ClO4 [(AAdtc = dithiocarbamate derivatives of amino acids, i.e., glycine (glydtc), L-isoleucine (i-leudtc) and L-proline (prodtc)] were synthesized. The compounds were characterized by IR and electronic spectroscopy, thermal analysis, cyclic voltammetry and conductivity measurements. In the case of the mixed ligand complexes, the thioureide ?(C?N) values were shifted to higher wave numbers compared to [Ni(AAdtc)2]. This observation shows the increased strength of the thioureide bond due to the presence of the ?-accepting phosphine. Electronic spectral studies suggest square planar geometry for the complexes. Thermal analyses of the complexes are in keeping with the proposed formulae. Almost all the complexes showed signs of decay above 170?C. At around 390?C, the final mass corresponded to NiS. Cyclic voltammetry showed a decrease of the electron density on the nickel in the mixed ligand complexes compared to [Ni(AAdtc)2].
The dependence of Ge detectors efficiency on the density of the samples in gamma-ray spectrometry
Authors: Vukasinovic Ivana , Todorovic Dragana , Popovic Dragana
Published: March 2008

The effect of the density of environmental samples on the counting efficiency of Ge detectors used in gamma-spectrometry was studied. The dependence ?ff(?) was determined for two HPGe detectors (relative efficiencies 18% and 20%) using five radioactive standard reference materials (silicone resins, epoxy resin, milk powder, soil) with different matrix densities (0.45-1.22 g/cm3) in Marinelli beakers (V = 500 cm3). The dependence of efficiency vs. density was found to be linear and the regression parameters for energies in the range of 60-2000 keV were determined, too. The effect of variation in density on the counting efficiency of Ge detectors is dominant in the range of lower energies (60-600 keV) and de creases with energies in the higher energy range.
Sums of like powers and some dense sets
Authors: Mijajlovic Zarko , Milosevic Milos , Perovic Aleksandar
Published: March 2008

We introduce the notion of the P-sequences and apply their properties in studying representability of real numbers. Another application of P-sequences we find in generating the Prouhet-Tarry-Escott pairs.
Canonical biassociative groupoids
Authors: Janeva Biljana , Ilic Snezana , Celakoska-Jordanova Vesna
Published: March 2008

In the paper Free biassociative groupoids, the variety of biassociative groupoids (i.e., groupoids satisfying the condition: every subgroupoid generated by at most two elements is a subsemigroup) is considered and free objects are constructed using a chain of partial biassociative groupoids that satisfy certain properties. The obtained free objects in this variety are not canonical. By a canonical groupoid in a variety V of groupoids we mean a free groupoid (R, ?) in V with a free basis B such that the carrier R is a subset of the absolutely free groupoid (TB, ?) with the free basis B and (tu ? R ? t, u ? R & t?u = tu). In the present paper, a canonical description of free objects in the variety of biassociative groupoids is obtained.
An enumerative problem in threshold logic
Authors: Kovijanic-Vukicevic Zana
Published: March 2008

The number of Boolean threshold functions is investigated. A new lower bound on the number of n-dimensional threshold functions on a set {0, 1,..., K ? 1} is given.
Essentially nonlinear theory of microdeformations in medium with periodic structure
Authors: Aero E.L.
Published: March 2008

Essentially nonlinear theory of micro and macro deformations of a medium with cardinally rearranging periodic structure is presented using a new model of double continuum with variable local topology. In a frame of proposed model there are two deformation modes (macroscopic and microscopic) when some threshold is reached. Some problems such as twin transitions, catastrophic deformation waves, shock and tilting bifurcation waves are considered. An exact solution describing elasto plastic fragmentation of medium is constructed also when double periodic domain superstructure are formed. There are solid rotons of opposite signs with singular defects between them. They appear in a critical field of macroscopic deformations of pure shear. When this bifurcation point is overcome then dimensions of domains are stabilized. The letter depend on value of macroscopic deformations. Some criterion of global stability is established. .
Spin driven motion in intense spacetime wave geometries
Authors: Burton D.A. , Tucker R.W. , Wang C.
Published: March 2008

The motion of a massive particle with intrinsic spin in a gravitational Einstein vacuum plane wave background is explored using the pole-dipole approximation to the Dixon multipole expansion for matter with compact support. Motivated by application to astrophysical processes the dynamical behavior of the spin and particle motion is described by numerically solving a system of non-linear first order ordinary differential equations. Some results are displayed in a reference frame adapted to the transverse nature of a monochromatic polarised gravitational wave of arbitrary intensity. .
Small elastic strains in finite elasto-plastic materials with continuously distributed dislocations
Authors: Cleja-Tigoiu S.
Published: March 2008

In this paper we propose a macroscopic model for elastoplastic materials with continuously distributed dislocations, when we restrict to small elastic strains, but the elastic rotations and plastic distorsions remain large. The material is not homogeneous and it behaves like an elastic material element with respect to non-holonomic configuration. The elastic curvature tensor vanishes. Consequently to complete the definition of the mathematical model it is sufficient to prescribe the evolution equation for the plastic distorsion (i.e. for time-dependent non-holonomic configuration), as well as the for the internal variables. .
On the trace-manifold generated by the deformations of a body-manifold
Authors: Boja Nicolae
Published: March 2008

In this paper, concerned to the study of continuous deformations of material media using some tools of modem differential geometry, a moving frame of Frenet type along the orbits of an one-parameter group acting on a so-called "trace-manifold", M, associated to the deformations, is constructed. The manifold M is defined as an infinite union of non-disjoint compact manifolds, generated by the consecutive positions in the Euclidean affine 3-space of a body-manifold under deformations in a closed time interval. We put in evidence a skew-symmetric band tensor of second order, ?, which describes the deformation in a small neighborhood of any point along the orbits. The non-null components ?i,i+i, (i =1,2), of ? are assimilated as like curvatures at each point of an orbit in the planes generated by the pairs of vectors (?i,?i+i) of a moving frame in M associated to the orbit in a similar way as the Frenet's frame is. Also a formula for the energy of the orbits is given and its relationship with some stiffness matrices is established.
Factors effecting water-vapor transport through fibers (a brief review)
Authors: Haghi A.K.
Published: March 2008

This review is a brief account of R& D results generated from drying behavior of carpets. First of all, the mathematical rela?tions are reviewed and then, they are developed in detail, which may be used to describe the moisture sorption mechanisms of car?pet. The effect of important parameters during the drying pro?cess are discussed and the mathematical relations are formulated to illustrate the range of their applications. However, challenges remain to be overcome through innovations, R& D investigations and advanced engineering, especially in designing process control devices.
Dynamics of a rigid rotor in the elastic bearings
Authors: Arkhipova Inga
Published: March 2008

As a rule in the studies of a rigid rotor in the elastic bearings the authors consider the linear system corresponding to the plane-parallel motion and the effect of self-centring under unlimited growth of the rotation frequency. In the present paper rotor is considered as a mechanical system with four degrees of freedom. Different motions of a statically and dynamically unbalanced vertical rotor supported in the non-linear bearings are studied.
A variational approach to the shock structure problem
Authors: Simic Srboljub
Published: March 2008

A variational approach to the shock structure problem is proposed. The set of governing equations, consisted of n first-order ordinary differential equations accompanied with 2n boundary conditions at ??, is put into variational form by means of least-squares method. The corresponding variational principle is adjusted for application of Ritz method. This direct method is used for construction of approximate analytical solutions to the shock structure problem and derivation of the estimates for the shock thickness. General procedure is applied to the study of Burgers' equation and equations of gas dynamics.
A form of MHD universal equations of unsteady incompressible fluid flow with variable elctroconductivity on heated moving plate
Authors: Boricic Zoran , Nikodijevic Dragisa , Milenkovic Dragica , Stamenkovic Zivojin
Published: March 2008

This paper deals with laminar, unsteady flow of viscous, incompressible and electro conductive fluid caused by variable motion of flat plate. Fluid electro conductivity is variable. Velocity of the plate is time function. Plate moves in its own plane and in "still" fluid. Present external magnetic filed is perpendicular to the plate. Plate temperature is a function of longitudinal coordinate and time. Viscous dissipation, Joule heat, Hole and polarization effects are neglected. For obtaining of universal equations system general similarity method is used as well as impulse and energy equation of described problem.
FEM model for reinforced concrete frames loaded by seismic forces
Authors: Kovacevic Dusan
Published: March 2008

Objective of the presented research is the formulation of one enough sophisticated and, for engineering practice, convenient finite element method (FEM) based numerical model for reinforced concrete frames loaded by seismic actions. For modeling of concrete and steel nonlinear behavior uniaxial constitutive rules are applied. The proposal for inclusion the frame joint deterioration, as well as, interaction of shear and flexural forces (inclined cracks effects), in this model, is given additionally. The results of few numerical tests (linear/nonlinear analysis of reinforced concrete frame loaded by three seismic actions) are given as an illustration of presented theoretical research.
Software development for subsonic aircraft’s unsteady longitudinal stability derivatives calculation
Authors: Maricic Nikola
Published: March 2008

Subsonic general configuration aircrafts? unsteady longitudinal aerodynamic stability derivatives can be estimated using finite element methodology based on the Doublet Lattice Method (DLM), the Slender Body Theory (SBT) and the Method of Images (MI). Applying this methodology, software DERIV is developed. The obtained results from DERIV are compared to NASTRAN examples HA21A and HA75H. A good agreement is achieved.
Stability of narrow-gap MHD Taylor-Couette flow with radial heating and constant heat flux at the outer cylinder
Authors: Deka R.K.
Published: March 2008

A linear stability analysis has been presented for hydromagnetic dissipative Couette flow, a viscous electrically conducting fluid between rotating concentric cylinders in the presence of a uniform axial magnetic field and constant heat flux at the outer cylinder. The narrow-gap equations with respect to axisymmetric disturbances are derived and solved by a direct numerical procedure. Both types of boundary conditions, conducting and non-conducting walls are considered. A parametric study covering on the basis of ?, the ratio of the angular velocity of the outer cylinder to that of inner cylinder, Q, the Hartmann number which represents the strength of the axial magnetic field, and N, the ratio of the Rayleigh number and Taylor number representing the supply of heat to the outer cylinder at constant rate is presented. The three cases of ? < 0 (counter rotating), ? > 0 (co-rotating) and ? = 0 (stationary outer cylinder) are considered wherein the magnetic Prandtl number is assumed to be small. Results show that the stability characteristics depend mainly on the conductivity on the cylinders and not on the heat supplied to the outer cylinder. As a departure from earlier results corresponding to isothermal as well as hydromagnetic flow, it is found that the critical wave number is strictly a monotonic decreasing function of Q for conducting walls. Also, the presence of constant heat flux leads to a fall in the critical wave number for counter rotating cylinders, which states that for large values of -?, there occur transition from axisymmetric to non-axisymmetric disturbance whether the flow is hydrodynamic or hydromagnetic and this transition from axisymmetric to non-axisymmetric disturbance occur earlier as the strength of the magnetic field increases.
Transport properties of a class of electromagnetic waves
Authors: Christie David
Published: March 2008

We demonstrate that in many cases, known frame-dependent transport equations for a propagating electromagnetic 2-form in an arbitrarily curved space-time can be replaced by a much simpler set of frame-independent equations. The frame-dependent equations can then be more easily recovered from the simpler set presented here if required. The relationship of such transport equations to the WKB approximation is also briefly discussed.
Thermodynamical modeling of viscous dissipation in magnetohydrodynamic ﬂow
Authors: Chandrasekar M. , Baskaran S.
Published: March 2008

A genuine variational principle developed by Gyarmati, in the field of thermodynamics of irreversible processes unifying the theoretical requirements of technical, environmental and biological sciences is employed to study the effects of viscous dissipation and stress work on MHD forced convection flow adjacent to a non-isothermal wedge. The velocity and temperature distributions inside the boundary layer are considered as simple polynomial functions and the variational principle is formulated. The Euler-Lagrange equations are reduced to simple polynomial equations in terms of bound?ary layer thicknesses. The values of skin friction coefficient and the Nusselt number are presented for various values of wedge angle parameter m, wall temperature exponent 2m, magnetic parameter ?, Prandtl number (Pr) and Eckert number (Ec). The present results are compared with known available results and the comparison is found to be satisfactory and the present study establishes the fact that the accuracy is remarkable.
Depression as a cause and consequence of victimization
Authors: Spasic Danijela
Published: March 2008

In this paper, I tried to show cause-and-consequence relationship between depression, as one of very frequent and specific mental disorders, and different forms of victimization. I wanted to make a modest contribution to the statement that depression, taken in a historic and temporal sequence despite our will and quite unexpectedly was transformed into some kind of "collective madness". At the beginning, it was a synonym for melancholy, a specific state into which those who were weaker were falling. But step by step and parallel with the global network of changes in all fields of human life, it got a character of world "infection" which spreading was being followed by the expansion of cardiovascular or malignant diseases, but without so obvious physical manifestations. Depression, as a long-term and "painful state of human soul" is often looking for shelter and rescue in abusing psychoactive substances, drugs and alcohols, and is often finding a way out in suicide behaviour, and therefore it becomes one of its dominant causes. Before that, it is, of course, usually manifested as a consequence of different forms of victimization; generally, it implies social conditions, either at macro or micro levels, and inadequate response of a person to them, but also criminal or any other negative acts, doings or omissions that could endanger or destruct any human good and put the man in a position of victim. In this way, depression "is closing its magic circle of causes and consequences", in which the man has three allies: himself community or other people, and time. Strength, quality and duration of allied assistance are reversely proportional to victimization dimension of depression.
Levetiracetam as an adjunct to phenobarbital treatment in cats with suspected idiopathic epilepsy
Authors: Bailey Kerry Smith , Dewey Curtis W. , Boothe Dawn M. , Barone Georgina , Kortz Gregg D.
Published: March 2008

Objective—To assess pharmacokinetics, efficacy, and tolerability of oral levetiracetam administered as an adjunct to phenobarbital treatment in cats with poorly controlled suspected idiopathic epilepsy.

Design—Open-label, noncomparative clinical trial.

Animals—12 cats suspected to have idiopathic epilepsy that was poorly controlled with phenobarbital or that had unacceptable adverse effects when treated with phenobarbital.

Procedures—Cats were treated with levetiracetam (20 mg/kg [9.1 mg/lb], PO, q 8 h). After a minimum of 1 week of treatment, serum levetiracetam concentrations were measured before and 2, 4, and 6 hours after drug administration, and maximum and minimum serum concentrations and elimination half-life were calculated. Seizure frequencies before and after initiation of levetiracetam treatment were compared, and adverse effects were recorded.

Results—Median maximum serum levetiracetam concentration was 25.5 μg/mL, median minimum serum levetiracetam concentration was 8.3 μg/mL, and median elimination half-life was 2.9 hours. Median seizure frequency prior to treatment with levetiracetam (2.1 seizures/mo) was significantly higher than median seizure frequency after initiation of levetiracetam treatment (0.42 seizures/mo), and 7 of 10 cats were classified as having responded to levetiracetam treatment (ie, reduction in seizure frequency of ≥ 50%). Two cats had transient lethargy and inappetence.

Conclusions and Clinical Relevance—Results suggested that levetiracetam is well tolerated in cats and may be useful as an adjunct to phenobarbital treatment in cats with idiopathic epilepsy.
Effects of training and strenuous exercise on hematologic values and peripheral blood leukocyte subsets in racing sled dogs
Authors: Davis Michael S. , Davis William C. , Ensign Wayne Y. , Hinchcliff Kenneth W. , Holbrook Todd C. , Williamson Katherine K.
Published: March 2008

Objective—To determine the effects of training and sustained submaximal exercise on hematologic values in racing sled dogs.

Design—Cohort study.

Animals—39 Alaskan sled dogs bred for endurance racing.

Procedures—Blood samples were collected prior to initiation of a 7-month training regimen (n = 39), after completion of the training regimen (19), and after completion of an 1,100-mile race (9), and a CBC, differential cell count, and flow cytometry for leukocyte surface antigens were performed.

Results—Both training and exercise caused significant decreases in PCV and hemoglobin concentration and significant increases in total WBC count. In contrast, training and exercise were not found to have significant effects on absolute numbers or fractions of CD4+ or CD8+ lymphocytes, other than a significant increase in the fraction of CD8+ lymphocytes associated with training.

Conclusions and Clinical Relevance—Results suggested that training and exercise induced changes in several hematologic values in racing sled dogs. Extracellular fluid volume expansion was the likely explanation for the training-induced decrease in PCV, and acute blood loss secondary to gastrointestinal tract bleeding was likely responsible for the decrease in PCV associated with acute exercise.
Efficacy of a continuous, multiagent chemotherapeutic protocol versus a short-term single-agent protocol in dogs with lymphoma
Authors: Simon Daniela , Moreno Sol Naranjo , Hirschberger Johannes , Moritz Andreas , Kohn Barbara , Neumann Stephan , Jurina Konrad , Scharvogel Stefan , Schwedes Claudia , Reinacher Manfred , Beyerbach Martin , Nolte Ingo
Published: March 2008

Objective—To compare response rates and remission and survival times in dogs with lymphoma treated with a continuous, multiagent, doxorubicin-based chemotherapeutic protocol or with a short-term single-agent protocol incorporating doxorubicin.

Design—Nonrandomized controlled clinical trial.

Animals—114 dogs with lymphoma.

Procedures—Dogs were treated with a chemotherapeutic protocol consisting of L-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate, and prednisolone (n = 87) or doxorubicin alone (27).

Results—63 of 86 (73%) dogs treated with the multiagent protocol (data on response was unavailable for 1 dog) and 14 of 27 (52%) dogs treated with the single-agent protocol had a complete remission. Dogs with lymphoma classified as substage ≤ and dogs with a high BUN concentration at the time of initial diagnosis were significantly less likely to have a complete remission. No significant difference in remission or survival time could be demonstrated between treatment groups. Incidence of hematologic and gastrointestinal tract toxicoses did not differ between treatment groups, with the exception that vomiting was more common among dogs treated with the multiagent protocol.

Conclusions and Clinical Relevance—In this population of dogs, we were not able to identify any significant difference in remission or survival times between dogs with lymphoma treated with a continuous, multiagent chemotherapeutic protocol and dogs treated with a short-term single-agent protocol involving doxorubicin.
Arthropathy caused by a lead bullet in a dog
Authors: Barry Sabrina L. , Lafuente M. Pilar , Martinez Steven A.
Published: March 2008

Case Description—A 3-year-old spayed female Labrador Retriever was evaluated for progressive lameness of the left forelimb 21 months after being shot in the elbow with a lead bullet.

Clinical Findings—Physical examination findings were consistent with moderate osteoarthritis of the left elbow joint. Orthogonal radiographic views of the elbow revealed multiple metallic fragments in and around the joint space as well as signs of osteoarthritis.

Treatment and Outcome—The elbow joint was evaluated arthroscopically. A lead-based bullet fragment was seen in the lateral synovial compartment and removed in multiple pieces. Excess fibrin and synovium were removed, and microfractures were created in exposed subchondral bone to stimulate neovascularization and fibrocartilage formation. In a follow-up telephone conversation 4 months after surgery, the owner reported a marked improvement in the lameness.

Clinical Relevance—Removal of lead intra-articular foreign bodies may be indicated even if the material is not believed to mechanically interfere with joint motion.
Comparison of tibial plateau angles in dogs with unilateral versus bilateral cranial cruciate ligament rupture: 150 cases (2000–2006)
Authors: Cabrera Sady Y. , Owen Tina J. , Mueller Maureen G. , Kass Philip H.
Published: March 2008

Objective—To compare tibial plateau angle (TPA) in dogs with unilateral versus bilateral cranial cruciate ligament (CCL) rupture, to compare right versus left TPA in dogs with bilateral CCL rupture, and to determine whether TPA can be used to predict whether a dog with unilateral CCL rupture would subsequently rupture the contralateral CCL.

Design—Retrospective case series.

Animals—150 dogs with unilateral (n = 58) or bilateral (92) CCL rupture.

Procedures—Medical records were reviewed and TPA was recorded. Dogs with unilateral CCL rupture that were not known to have ruptured the contralateral ligament were followed up for a minimum of 2 years.

Results—Dogs with unilateral CCL rupture were significantly older (median, 7.0 years) than dogs with bilateral CCL rupture (median, 4.5 years). Median TPA for dogs with unilateral CCL rupture (26°) was not significantly different from median TPA for dogs with bilateral rupture (27° in both the right and left limbs), and right and left TPAs were not significantly different in dogs with bilateral CCL rupture. There was no correlation between TPA and the time interval between diagnosis of the initial and subsequent CCL ruptures in dogs with bilateral CCL rupture.

Conclusion and Clinical Relevance—Results suggested that TPA in the range studied (mostly < 35°) was not a useful predictor of contralateral CCL rupture among dogs with unilateral CCL rupture, although age may be a risk factor for development of bilateral CCL rupture. The incidence of bilateral CCL rupture may be higher than previously reported.
Relationship between Doppler blood pressure and survival or response to treatment in critically ill cats: 83 cases (2003–2004)
Authors: Silverstein Deborah C. , Wininger Fred A. , Shofer Frances S. , King Lesley G.
Published: March 2008

Objective—To evaluate the relationship between Doppler blood pressure (DBP) and survival or response to treatment in critically ill cats.

Design—Retrospective case series.

Animals—83 cats.

Procedures—Medical records from cats admitted to the intensive care unit with at least 2 recorded DBP measurements were included in the study. Hypotension was defined as 1 or more DBP measurements d 90 mm Hg. Change in blood pressure, survival to hospital discharge, heart rate, rectal temperature, PCV, plasma pH, serum ionized calcium concentration, disease process, body weight, age, duration of hospitalization, and catecholamine treatment were also evaluated.

Results—39 cats were included in the hypotensive group, and 44 were consistently normotensive. Overall survival rate was 53% (44/83), with a significantly higher mortality rate in the hypotensive group (64% vs 32%). Among other variables, only low rectal temperature and low PCV were significantly associated with hypotension. Hypotensive cats with an increase in blood pressure of ≥ 20 mm Hg during hospitalization were more likely to survive to discharge (mortality rate, 69% vs 17%).

Conclusions and Clinical Relevance—Hypotensive cats had increased mortality rate with lower rectal temperatures and lower PCV, compared with normotensive critically ill cats. The implications of these findings with regard to treatment remain to be elucidated, but addressing these abnormalities may be appropriate.
Multinodular pulmonary fibrosis in five horses
Authors: Wong David M. , Belgrave Rodney L. , Williams Kurt J. , Del Piero Fabio , Alcott Cody J. , Bolin Steven R. , Marr Celia M. , Nolen-Walston Rose , Myers Ronald K. , Wilkins Pamela A.
Published: March 2008

Case Description—5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress.

Clinical Findings—Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils and macrophages within the alveoli, and occasional intranuclear inclusion bodies within alveolar macrophages. Equine herpesvirus type 5 was detected in samples of lung tissue, bronchoalveolar lavage fluid, or both via polymerase chain reaction assay in all cases. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was established.

Treatment and Outcome—Horses were provided supportive treatment and were administered a variety of medications including corticosteroids and acyclovir. Two horses survived and returned to their previous level of activity. Three horses were euthanized because of either deterioration of clinical condition (n = 2) or failure to improve within 4 weeks of initiation of treatment (1).

Clinical Relevance—EMPF should be considered as a differential diagnosis for adult horses with interstitial pneumonia and should be suspected on the basis of characteristic radiographic, ultrasonographic, and histopathologic findings. Equine herpesvirus type 5 is found in association with EMPF; although the exact pathogenic role this virus plays in EMPF is unknown, equine herpesvirus type 5 may be an etiologic agent or cofactor in the development of EMPF.
A field evaluation of mortality rate and growth performance in pigs vaccinated against porcine circovirus type 2
Authors: Horlen Kyle P. , Dritz Steve S. , Nietfeld Jerome C. , Henry Steven C. , Hesse Richard A. , Oberst Richard , Hays Michael , Anderson Joseph , Rowland Raymond R. R.
Published: March 2008

Objective—To evaluate, under field conditions, the effects of a commercial porcine circovirus type 2 (PCV2) vaccine on mortality rate and growth performance in a herd infected with PCV2 that had a history of porcine circovirus disease.

Design—Randomized controlled clinical trial.

Animals—485 commercial, cross-bred, growing pigs.

Procedures—Prior to weaning, pigs were randomly assigned within litter to a vaccination or unvaccinated control group. Pigs in the vaccination group were given a commercial PCV2 vaccine at weaning and 3 weeks later. Mortality rate was recorded, and pigs were weighed prior to vaccination, when moved from the nursery, and prior to marketing. Infection status was assessed by serologic testing and detection of viral DNA in serum.

Results—Compared with control pigs, pigs vaccinated against PCV2 had a significantly lower mortality rate during the finishing phase, significantly higher average daily gain during the finishing phase, and significantly lower likelihood of being lightweight at the time of marketing. For vaccinated pigs, overall mortality rate was reduced by 50% and average daily gain during the finishing period was increased by 9.3%. At the time of marketing, vaccinated pigs weighed an average of 8.8 kg (19.4 lb) more than control pigs, without any difference in days to marketing. Serum PCV2 antibody titers increased in control pigs, and PCV2 DNA was detected, indicating active PCV2 infection.

Conclusions and Clinical Relevance—Results suggested that vaccination against PCV2 was effective at reducing mortality rate and improving growth performance among pigs in a herd infected with PCV2.
Gap ecology in Florida scrub: Species occurrence, diversity and gap properties
Authors: Menges Eric S. , Craddock Alaä , Salo Jessica , Zinthefer Robin , Weekley Carl W.
Published: March 2008

Questions:Studies of gap effects have been conducted mainly in forests. We studied gap ecology in a pyrogenicCeratiola ericoides(Florida rosemary) dominated shrubland and asked: How do gap size and the frequency of large gaps change across the fire chronosequence? Do larger gaps differ from smaller gaps in vegetation structure or species diversity? Are effects of gaps independent of, or dependent upon, time‐since‐fire? Are larger gaps refugia for herbs and subshrubs?

Location:Archbold Biological Station, Lake Wales Ridge, south‐central Florida, USA.

Methods:We investigated plant species occurrence and diversity in 805 gaps (areas free of shrubs taller than 50 cm) in 28 fire‐dependent Florida rosemary scrub sites. We collected quantitative cover data in a subset of seven sites.

Results:Gap area distribution was lognormal. The largest gaps occurred throughout all but the longest time‐since‐fire intervals. Gaps were smallest in the longest unburned site but otherwise did not show strong patterns across the fire chronosequence. Species diversity measures increased with increasing gap area, with herbaceous diversity increasing with both gap area and bare sand. Herb diversity (H') decreased with time‐since‐fire. Larger gaps are refugia for some species. Of 14 species occurring in 25–75% of gaps, 13 had increased occupancy with increasing gap area, and gap area was the strongest predictor of occupancy for seven species of herbs and shrubs. Time‐since‐fire was the strongest predictor of occupancy for five species, including four ground lichens that increased with time‐since‐fire.

Conclusions:Community structure within Florida scrub gaps is influenced by gap size, which in turn is affected by fire, the dominant ecological disturbance. We present a conceptual model that considers both gap size and time‐since‐fire as drivers of community structure and herbaceous plant diversity in Florida scrub. Because gap properties (independently of fire) have strong influences on species assemblages in Florida rosemary scrub gaps, fire management should consider the number and size of gaps across the landscape.
Fine Chemicals
Authors: Pollak Peter
Published: March 2008

Fine chemicals are low volume, high priced, chemical intermediates, and bulk active ingredients, which are used primarily in the preparation of pharmaceuticals and agrochemicals, these chemicals are also used in other specialties, eg, household and personal care ingredients, electronic chemicals, and flavors and fragrances. In contrast to specialty chemicals, these intermediates are sold within the chemical industry and according to specifications rather than performance criteria. Fine chemicals typically are manufactured by batch processes in multipurpose plants starting from commodity chemicals and involving several distinct chemical or biotechnological steps. A typical fine chemical plant consists of a “wet” section, where the chemical reactions and the preliminary solid–liquid separations are carried out, and a “dry” section, where the product drying, milling, sieving, and packaging takes place. The wet section is further divided into production trains that allow individual process steps to be performed. The main apparatus are jacketed and agitated 1–10‐m
3
reaction vessels connected to overhead condensers, and filters resp. centrifuges. The smallest production unit is a “train”. A train usually consists of three jacketed reactors with overhead condensers, head tanks, receivers, and a filtration unit. Several trains are regrouped in a production building. A complete plant also comprises an administrative building, R&D, and analytical laboratories, a pilot plant, utilities, maintenance and waste disposal units, and a warehouse.
Xylylene Polymers
Authors: Kumar Rakesh
Published: March 2008

Pinhole‐free coatings of outstanding conformality and thickness uniformity are produced by exposing a substrate to a controlled deposition of pure gaseous monomer through the unique chemistry ofp‐xylylene, which is thermally stable, but very reactive toward polymerization with other like molecules, in a process known as vapor deposition polymerization (VDP). A high molecular weight coating of poly(p‐xylylene) (PPX) is produced. Recent VDP developments are stressed in the article.

The convenient generation of the extremely reactive monomer is accomplished by thermal cleavage of its stable dimer,cyclo‐di‐p‐xylylene (DPX), commercially in the Gorham process. The PPXs formed as coatings in the Gorham process are referred to generically as parylenes. Parylenes N, C, D, and Parylene HT are polymer coatings produced by the Gorham process using the dimers DPXN, DPXC, DPXD, and DPX‐HT respectively. These dimers are the feedstocks for the coating process. The Parylene C monomer, chloro‐p‐xylylene, has become the de facto performance standard owing to its room temperature volatility. The VDP processes using means other than pyrolytic cleavage of DPX to generate reactive monomer, none practiced commercially, include photopolymerization and plasma polymerization, as well as imidization to produce polyimide films.

Manufacture of commercial DPXN is through two routes: direct pyrolysis ofp‐xylene and the Hofmann elimination route. Both DPXC and DPXD are prepared from DPXN by chlorinating. Thermodynamic considerations of the parylene process by VDP are covered. The importance of the physical processes of condensation and diffusion in VDP are treated, as is the propagation reaction.

The VDP produces films of uniform thickness having excellent conformality and purity. Electrical properties merit their use in electronic construction. Barrier, spectral, and optical properties are also useful. Crystallinity determines important properties of mechanical strength at elevated temperatures and solvent resistance, which constitute the principal advantages of PPX materials. Uses include circuit boards, hybrid circuits, semiconductors, capacitors, the bathythermograph, medical uses (as in pacemakers), artifact conservation, and in laser fusion targets. They are also used as barrier coatings, in corrosion control, and as dry lubricants. The dimers present little concern in handling and storage to an experienced operator. In ancillary operations, such as cleaning or adhesion promotion, suitable precautions given in manufacturers' Material Safety Data Sheets should be observed.
Isoprene Polymers
Authors: Senyek Michael L.
Published: March 2008

Isoprene was first isolated from the pyrolysis products of natural rubber. The first preparation of polyisoprene was reported in 1879. In 1950, the goal of preparing synthetic
cis
1,4‐polyisoprene as a counter part to natural rubber was achieved. Attention was then focused on commercial preparation of isoprene for polymerization use. Shortly after the discovery of stereospecific catalysts, the first commercial polyisoprene plant came on stream in 1959–1960 using a lithium catalyst. Isoprene is a reactive diene that undergoes cycloaddition, electrophilic, nucleophilic, free‐radical, and coordinated catalytic addition, and thermal dimerization. Information on the production of isoprene by naphtha cracking as well as the synthetic processes is detailed. Depending on the catalyst and conditions, isoprene may undergo 1,2,3,4, or 1,4 addition leading to several isomeric structures. Coordination catalysts, alkali metal catalysts, and Alfin catalysts are important for polymerization and are discussed. Chemical modification of polymers is a convenient way of altering physical and mechanical properties. Highly unsaturated polymers such as polyisoprene are easily modified because the olefinic bond is readily available. Their high reactivity with a variety of chemical substances offers advantages in chemical modification and vulcanization. However, reaction with oxygen and ozone causes degradation and loss of physical and mechanical properties. Synthetic polyisoprene is processed on conventional rubber machinery. Compounding technology is similar to that used for natural rubber. Typical formulations are given. A brief discussion of isoprene copolymers and 1,4‐
trans
‐polyisoprene is included. Isoprene is classified as a flammable liquid. It is a moderate irritant to the skin, eyes, and mucous membranes. The primary use for
cis
‐1,4‐polyisoprene is in tires and tire products. It is also used, eg, in molded and mechanical goods, adhesives, belts, foam rubber, and elastic threads.. Automotive molded products and medical applications are typical.
Trans
‐1,4‐Poyisoprene can be extracted, calendered, injection molded, and compression molded. It can be used in blends with other polymers. Its main use is in golf ball covers.
Macrocyclic Polymers
Authors: Brunelle Daniel J.
Published: March 2008

Macrocyclic polymers, defined as polymers having more than 20 atoms in a ring structure, have been known for many decades. Theories of macrocycle formation via ring‐chain equilibration or end‐to‐end cyclization were developed in the 1950's, and soon followed by isolation, characterization, and synthesis of macrocyclic polymers. Both high molecular weight (Mn > 10,000Da) and oligomeric macrocycles have been intensively studied in the past 20 years. Although much of the research has been academic, macrocyclic polymers are now commercially available as well. This article details some of the recent synthetic efforts aimed at macrocyclic polymer generation, and also describes utilization of macrocyclic oligomers as substrates for ring‐opening polymerization.
Selective antiaggressive effect of an alpha‐2 adrenoceptor agonist naphthylmedetomidine in mice
Authors: Votava Martin , Hess Ladislav , Kršiak Miloslav
Published: March 2008

Alpha‐2 adrenoceptors (α2‐ARs) are critically involved in regulating neurotransmitter release from sympathetic nerves and neurons and play an important role in the regulation of awareness, arousal and vigilance. In our recent study, dexmedetomidine, a full α2‐AR agonist, produced antiaggressive effects in the social conflict test in mice at doses that were twice smaller than those producing sedation. The aim of this study was to ascertain antiaggressive effect of a novel drug naphthylmedetomidine, with a more selective α2‐AR activity. Behavioral effects of naphthylmedetomidine (150–1200 µg/kg i.p.) were studied in the activity cage and in the social conflict tests in mice. Naphthylmedetomidine dose dependently decreased aggressive behavior during social conflict in aggressive mice with significant reduction already at the lowest doses tested (150 µg/kg), whereas locomotion and social investigation were significantly decreased only after four times bigger dose of naphthylmedetomidine (600 µg/kg) in aggressive mice. Naphthylmedetomidine had no effect on aggression in nonaggressive mice. Naphthylmedetomidine reduced locomotion in the activity cage significantly only at the highest doses tested (600 and 1200 µg/kg), and this effect was only partially reversed by administration of high doses of an alpha‐2 antagonist atipamezole (3 and 10 mg/kg). In nonaggressive mice, the difference between the dose reducing dominant social behavior (social investigation) and locomotion (150 and 300 µg/kg, respectively) was smaller than in aggressive mice. In conclusion, naphthylmedetomidine showed a very strong and selective antiaggressive effect in aggressive mice, which was devoid of locomotion‐inhibiting/sedative effect. This study suggests that naphthylmedetomidine may have clinical potential as antiaggressive drug. Aggr. Behav. 34:394–403, 2008. © 2008 Wiley‐Liss, Inc.
A New Hybrid Phosphine Ligand for Palladium‐Catalyzed Amination of Aryl Halides
Authors: Suzuki Ken , Hori Yoji , Kobayashi Tohru
Published: March 2008

A new hybrid phosphine was designed. The phosphine combines two common structural characteristics found among the effective phosphine ligands reported recently, namely, three tert‐alkyl substituents binding to the phosphorus and an aryl group at an appropriate position. A hybrid phospine/palladium system is versatile and effective for the coupling reaction of various aryl halides with primary and secondary amines including carbazole.
An Efficient Method for the Selective Iridium‐Catalyzed Monoalkylation of (Hetero)aromatic Amines with Primary Alcohols
Authors: Blank Benoît , Madalska Martyna , Kempe Rhett
Published: March 2008

An efficient multi‐gram scale synthesis protocol of a variety of P,N ligands is described. The synthesis is achieved in a two‐step reaction. First, the amine is deprotonated and subsequently the chlorophosphine is added to yield the corresponding P,N ligand. Deprotonation of the amine is normally achieved with n‐BuLi at low temperature, but for the preparation of ligands with a 2,2′‐dipyridylamino backbone and phosphines with a high steric demand KH has to be employed in combination with reaction temperatures of 110 °C for the salt metathesis step. The reaction of two equivalents of a selected P,N ligand with one equivalent of the iridium complex [IrCl(cod)]2 (cod=1,5‐cyclooctadiene) affords P,N ligand‐coordinated iridium complexes in quantitative yield. X‐Ray single crystal structure analysis of one of these complexes reveals a monomeric five‐coordinated structure in the solid state. The iridium complexes were used to form catalysts for the N‐alkylation of aromatic amines with alcohols. The catalyst system was optimized by studying 8 different P,N ligands, 9 different solvents and 14 different bases. Systematic variation of the substrate to base and the amine to alcohol ratios as well as the catalyst loading led to optimized catalytic reaction conditions. The substrate scope of the developed catalytic protocol was shown by synthesizing 20 different amines of which 12 could be obtained in isolated yields higher than 90%. A new efficient catalyst system for the selective monoalkylation of primary aromatic and heteroaromatic amines with primary aromatic, heteroaromatic as well as aliphatic alcohols has been established. The reaction proceeds with rather moderate catalyst loadings.
Synthesis and Catalytic Applications of Mesoporous Polymer Colloids in Olefin Hydrosilylation
Authors: Zhang Yugen , Zhao Lan , Patra Pranab K. , Ying Jackie Y.
Published: March 2008

Mesoporous polymer particles (MPPs) have been synthesized by using the spherical microparticles of siliceous mesocellular foam (MCF) as a hard template. The MPPs possessed a robust structure with ultralarge mesopores, and a clean and inert surface. The surface properties of the MPPs could be tailored for various applications by using different functionalized monomers. An imidazolium‐pyrrolidine ligand was successfully immobilized onto MPPs and used as a supported platinum organometallic catalyst in olefin hydrosilylation. The MPP‐supported catalyst provided superior activity and selectivity for this reaction as compared to the MCF‐supported catalyst.
Structure of operating domains of loop reactors
Authors: Nekhamkina Olga , Sheintuch Moshe
Published: March 2008

A loop reactor (LR), composed as an N‐unit loop with step‐wise shifted inlet and outlet ports, is one of suggested technological solutions for low‐concentration volatile organic compounds (VOC) combustion. Such a scheme ensures a sufficiently high temperature with autothermal behavior and nearly uniform catalytic utilization. The main drawback of the LR is a very narrow window of switching velocities that sustain a stable “frozen” solution that exists if the switching and the pulse velocity are synchronized. In the present work we show the existence of many “finger”‐like domains of complex frequency‐locked solutions that allow to significantly extend the operation domain, rendering the LR scheme more attractive for practical implementation. A brief comparison with the other heat recuperation technologies (reverse flow and circular loop reactors) is presented. © 2008 American Institute of Chemical Engineers AIChE J, 2008