bluuebunny/crossref_metadata_2025 huggingface dataset:
Anomalous electronic transport in metallic nanomultilayer at all length scales: Influence of grain boundary and interface boundary
Authors: Liu M.X. , Xu K.W.
Published: June 2008

Scale-dependent microstructure and electronic transportation of Ni/Al-type nanomultilayers as a function of the bilayers number, the modulated ratio, and the periodicity were investigated. The deposited multilayers have anisotropic nanocrystalline structure and asymmetrical interfaces. This special interfacial feature is the result of asymmetrical diffusion of Ni to Al lattice near the Ni–Al interface. Anomalous resistivity enhancement increases with decreasing both the periodicity and the modulated ratio, but is insensitive to the number of bilayers. Accounting for the effects of grain boundary and interface boundary, the dominative mechanism at distinct length scales can be interpreted with the modified model of those of Fuchs–Sondheimer and Mayadas–Shatzkes. Especially for the thinnest film with smallest modulated ratio, the intermixing effect turns out to be the crucial mechanism in the electronic transportation of metallic nanomultilayers.
Oxidation behavior of pressureless liquid-phase-sintered α-SiC in ambient air at elevated temperatures
Authors: Rodríguez-Rojas F. , Borrero-López O. , Ortiz A.L. , Guiberteau F.
Published: June 2008

The long-duration oxidation behavior of a pressureless liquid-phase-sintered (LPS) α-SiC with 10 vol% Y3Al5O12additives was studied by furnace oxidation tests in ambient air at 1100 to 1450 °C. The oxidation of this LPS SiC ceramic was found to be passive throughout these temperatures due to the formation of oxide scales, with a change in the oxidation behavior occurring at 1350 °C. It was also found that the oxidation behavior is very complex, exhibiting two distinct stages at all temperatures: (i) initial nonparabolic oxidation, where the rate-limiting mechanism is the outward diffusion of Y3+and Al3+cations from the secondary intergranular phase into the oxide scale with the activation energy of the oxidation being 504 ± 32 kJ/mol, followed by (ii) parabolic oxidation below 1350 °C, where the rate-determining mechanism is the inward diffusion of oxygen through the oxide scale with the activation energy being 310 ± 47 kJ/mol, or paralinear oxidation at and above 1350 °C, where oxidation is controlled by some mixed reaction/diffusion process. The existence of two oxidation regimes reflects the progressive crystallization of the oxide scale during the oxidation. Finally, guidelines are provided for the design and fabrication of low-cost, highly oxidation-resistant LPS SiC or other LPS nonoxide ceramics.
Doping, compensation, and photosensitivity of detector grade CdTe
Authors: Babentsov V. , Franc J. , Fauler A. , Fiederle M. , James R.B.
Published: June 2008

We studied the resistivity, photosensitivity, photoluminescence, and surface photovoltage of CdTe crystals doped with Ge or Sn to extend our knowledge of the influence of the deep-donor level on compensation and afterglow effects. We demonstrated a strong correlation between photosensitivity caused by photoelectrons with Fermi-level variations near the GeCd0/2+ or SnCd0/2+ energy levels. Surface photovoltage measurements confirmed that when the concentration of residual acceptors varied along the direction of growth, then trapping conditions dramatically changed as a defect was converted from a neutral state to doubly charged positive one.
Effect of the electropulsing on mechanical properties and microstructure of an ECAPed AZ31 Mg alloy
Authors: Du X.N. , Yin S.M. , Liu S.C. , Wang B.Q. , Guo J.D.
Published: June 2008

The mechanical properties and corresponding microstructure development of the AZ31 Mg alloy after treatment with equal channel angular pressing (ECAP) and subsequent electropulsing (ECP) was investigated. Comparing the ECAP+ECP-treated AZ31 alloy with the ECAP-treated alloy, the elongation to failure was improved significantly, while the yield stress and the ultimate tensile strength were not decreased, the grain sizes were slightly increased and more homogeneous, and the texture was barely changed. The main mechanism for the evolution of the structures and properties might be ascribed to the increased nucleation rate on recrystallization and the decreased dislocation density during the ECP treatment. It was reasonable to expect that the ECAP+ECP treatment would provide a promising approach for enhancing the mechanical properties of the Mg alloys.
Mechanical properties characterization of a viscoelastic solid using low-frequency large-amplitude oscillatory indentations with a sharp tip
Authors: Fujisawa N. , Swain M.V.
Published: June 2008

A viscoelastic solid was contacted by a pointed indenter using low-frequency large-amplitude sinusoidal load functions to determine its contact stiffness in a manner similar to that of the continuous stiffness measurement (CSM) technique but in a quasi-static condition. The contact stiffness of a viscoelastic solid determined by the CSM technique, or the dynamic stiffness, is known, from previous CSM-based studies, to overestimate the quasi-static contact stiffness. The contact stiffness of a viscoelastic solid determined in a quasi-static manner is thus hypothesized to help predict the contact depth more accurately. A new analysis procedure based on truncated Fourier series fitting was developed specifically to process the large amplitude sinusoidal indentation data. The elastic modulus of the material characterized in this work was in agreement with that determined by dynamic mechanical analysis, thereby providing evidence for the validity of the present method in characterizing other viscoelastic materials.
Microwave dielectric properties and vibrational spectroscopic analysis of MgTe2O5 ceramics
Authors: Subodh G. , Ratheesh R. , Jacob M.V. , Sebastian M.T.
Published: June 2008

MgTe2O5 ceramics were prepared by solid-state route. These materials were sintered in the temperature range of 640–720 °C. The structure and microstructure of the compound was investigated using x-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. The dielectric properties of the ceramics were studied in the frequency range 4–6 GHz. The MgTe2O5 ceramics have a dielectric constant (ϵr) of 10.5, quality factors (Qu × f) of 61000 at 5.3 GHz, and temperature coefficient of resonant frequency (τf) of −45 ppm/°C at the optimized sintering temperature of 700 °C. The microwave dielectric properties of these materials at cryogenic temperatures were also investigated.
High ductility of ultrafine-grained steel via phase transformation
Authors: Cheng S. , Choo H. , Zhao Y.H. , Wang X-L. , Zhu Y.T. , Wang Y.D. , Almer J. , Liaw P.K. , Jin J.E. , Lee Y.K.
Published: June 2008

There is often a tradeoff between strength and ductility, and the low ductility of ultrafine-grained (UFG) materials has been a major obstacle to their practical structural applications despite their high strength. In this study, we have achieved a ∼40% tensile ductility while increasing the yield strength of FeCrNiMn steel by an order of magnitude via grain refinement and deformation-induced martensitic phase transformation. The strain-rate effect on the inhomogeneous deformation behavior and phase transformation was studied in detail.
Ductile-to-brittle transition induced by increasing strain rate in Sn–3Cu/Cu joints
Authors: Zou H.F. , Zhang Z.F.
Published: June 2008

The current study revealed the effects of strain rate on tensile strength and ductile-to-brittle transition of Sn–3Cu/Cu joints in the strain rate range of 4.2 × 10−5 to 2.4 × 10−1 s−1. Experimental results indicate that these joints broke in a ductile manner at low strain rates with a rapid increase in the tensile strength but displayed a brittle manner at higher strain rates with a slow increase in the tensile strength, indicating a typical ductile-to-brittle transition feature. A method was proposed to estimate the interfacial strength between the solder and the intermetallic compounds.
Novel flame retardant epoxy/clay nanocomposites prepared with a pre-ground phosphorus-containing organoclay
Authors: Chen-Yang Y.W. , Wang W.S. , Tang J.C. , Wu Y.W. , Chen H.S.
Published: June 2008

A series of novel epoxy/clay nanocomposites (EPOCg-x) were prepared with a selected epoxy resin and x wt% of a mechanically ground phosphorus-containing organoclay (POCg). The results of x-ray diffraction (XRD), Fourier transform infrared, and field emission scanning electron microscopy measurements showed that POCg was size-reduced, and its silicate layers were disordered by the grinding process. The results of XRD and transmission electron microscopy of the nanocomposites suggested that the POCg particles were well-dispersed in the epoxy matrix with a combination of intercalation and destruction platelet structures. The as-prepared nanocomposites remained thermally stable above 376 °C. Furthermore, the storage modulus in the glass state, surface hardness, char residue, and limiting oxygen index (LOI) of the as-prepared nanocomposite were all significantly increased with increasing the POCg content. The large increment of LOI, 10 units higher than that of neat epoxy, indicated that an extraordinary enhancement on flame retardancy was obtained from EPOCg-5.
Preparation of silver spheres by aggregation of nanosize subunits
Authors: Halaciuga Ionel , Goia Dan V.
Published: June 2008

Dispersed uniform spherical silver particles were prepared in the absence of a protective colloid by rapidly mixing concentrated isoascorbic acid and silver-polyamine complex solutions. By varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, it was possible to tailor the size of the resulting metallic particles in a wide range (80 nm to 1.3 μm). The silver spheres were formed by aggregation of nanosize subunits, the presence of which was detected by both electron microscopy and x-ray diffraction. Due to its simplicity, high metal concentration, and the absence of polymeric dispersants, the described method represents an advantageous route to manufacture cost-effectively dispersed uniform silver particles for electronic applications.
Anisotropic mechanical properties of ultra-incompressible, hard osmium diboride
Authors: Chung Hsiu-Ying , Yang J-M. , Tolbert S.H. , Kaner R.B.
Published: June 2008

Borides of high electron density metals such as Os show promise as hard materials. Arc-melting elemental osmium and boron under an argon atmosphere produced osmium diboride (OsB2). Both a Vickers diamond microindenter and a Berkovich nanoindenter were used to measure hardness. Vickers microindentation indicates that the hardness of OsB2 increases significantly with decreasing applied load. The average hardness reaches approximately 37 GPa as the applied load is lowered to 0.245 N. The hardness is found to be highly dependent on the crystallographic orientation. For the {010} grains, along the 〈100〉 direction, the average hardness is significantly higher than that in the orthogonal 〈001〉 direction. Cracks associated with pop-in events in the nanoindentation load–displacement curves are observed in the {010} grains. The measured Young’s modulus of OsB2 is 410 ± 35 GPa, which is comparable to that obtained from first-principles calculations.
Delamination-induced dielectric breakdown in Cu/low-k interconnects
Authors: Tan T.L. , Gan C.L. , Du A.Y. , Tan Y.C. , Ng C.M.
Published: June 2008

Delamination at an interface with the weakest adhesion strength, which is found to be between the SiC(N) capping layer and the SiOCH low-k dielectric, is a potential failure mechanism contributing to time-dependent dielectric breakdown (TDDB) reliability. Bond breaking at that interface is believed to be driven by a field-enhanced thermal process and catalyzed by leakage current through the capping layer based on physical analyses and TDDB measurements. Delamination is found to be easier in terminated tips and corners than in parallel comb lines due to the layout orientation of the Cu lines. Moreover, TDDB activation energy Ea can be an indicator of the ease of delamination, whereby a lower Ea corresponds to an easier delamination.
Novel precursor-derived Al–C–N–(O)-based ceramic additive for the low-temperature pressureless sintering of silicon nitride
Authors: Lee Sea-Hoon , Weinmann Markus , Gerstel Peter , Rixecker Georg , Choi Sung-Churl , Aldinger Fritz
Published: June 2008

A polymer, which by pyrolysis transforms into Al–C–N–(O) ceramics, was synthesized from trimethylamine alane and cyan amide, and its applicability as a sintering additive for Si3N4was investigated. Si3N4powders were mixed with the precursor by treatment with organic slurries of the precursor to induce the homogeneous distribution of the additive. The green-bodies were pretreated in air or NH3at 800 °C to control the chemical composition of the additive, through which the densification of Si3N4could be improved. Dense samples with very fine grains (<2 μm) were obtained after sintering at 1600 °C in 0.1 MPa N2. Besides silicon nitride, submicrometer silicon carbide particles were observed in the samples, indicating that this procedure (i.e., the use of this novel sintering additive) also allows for the fabrication of SiC–Si3N4composites.
Copper Sulfate Toxicity to Channel Catfish Fry: Yolk Sac versus Swim-Up Fry
Authors: Straus David L
Published: June 2008

Yolk sac and swim-up fry from five separate spawns of channel catfish Ictalurus punctatus were exposed to dissolved copper sulfate (CuSO4) in a series of static toxicity bioassays to observe age sensitivity at 24 and 48 h in waters with two different chemistries at a temperature of 23.1 ± 0.47°C (mean ± SD). The two waters were (1) well water with a total alkalinity (as CaCO3) of 217 mg/L and a total hardness of 126 mg/L and (2) a 1:1 mixture of well water and deionized (WDI) water with a total alkalinity of 112 mg/L and a total hardness of 66 mg/L. Probit median lethal concentration (LC50) values were estimated with PoloPlus using the nominal CuSO4 concentrations. The mean 24-h LC50 values for the yolk sac fry were 62.8 ± 37.1 mg of CuSO4/L in the well water and 10.2 ± 3.4 mg/L in the WDI water; the 24-h LC50 values for the swim-up fry were 13.5 ± 11.5 mg/L in well water and 4.3 ± 4.4 mg/L in WDI water. The mean 48-h LC50 values for the yolk sac fry were 14.9 ± 5.0 mg/L in well water and 3.9 ± 1.6 mg/L in WDI water; the 48-h LC50 values for the swim-up fry were 3.5 ± 1.8 mg/L in well water and 1.5 ± 0.3 mg/L in WDI water. The yolk sac fry were about 4.6 times more tolerant of CuSO4 than the swim-up fry at 24 h and 4.3 times more tolerant at 48 h. Fry were about 4.7 times (at 24 h) and 3.3 times (at 48 h) more sensitive to CuSO4 in water with low alkalinity and hardness (WDI water) than in water with high alkalinity and hardness (well water). The differences in LC50 values between the different spawns of each fry type and time within a water type are attributed to natural variation and channel catfish strain.
Degree-Days as a Tool to Determine the Heating Requirement for Channel Catfish Spawning in Earthen Ponds
Authors: Pawiroredjo Patrice , Lamoureux Jonathan , Hall Steven G , Tiersch Terrence R
Published: June 2008

Temperature and time are critical in determining when channel catfish Ictalurus punctatus will be physiologically ready to spawn (conditioned). Natural and hormone-induced spawning can occur when the fish are held at, above, or below specific temperatures for a largely undetermined minimum period of time. This period of conditioning can also be described as the heating requirement for spawning. We used degree-days as a standard unit to describe and quantify the heating requirement for channel catfish spawning, and we developed specific terminology and standard parameters to support the use of the degree-day concept for channel catfish spawning. The heating requirements for spawning were quantified by (1) retrospectively calculating degree-day values using previously collected data (2000–2003) from heated and ambient-temperature ponds before and during the natural spawning season and (2) calculating degree-days using data from fish conditioned for the 2004 natural spawning season at different thermal regimes in heated ponds at three threshold temperatures. These results were used to calculate spawning probabilities to enable future spawning predictions using degree-days. The values calculated using the 21°C threshold were more consistent than those calculated using the two other thresholds: 18°C and 24°C. The heating requirements for spawning in heated ponds before the natural spawning season were not different from the requirements for spawning in ambient-temperature ponds during the natural spawning season. Degree-day guidelines for channel catfish spawning were proposed based on the results of the degree-day calculations and spawning probabilities using a commercial definition that corresponded with the 21°C threshold. According to those guidelines, channel catfish spawning can begin in 0.04-ha ponds in southern Louisiana after the accumulation of 57–172 degree-days, with a median value of 99 degree-days.
Seasonally Adjusting Ration Levels of Juvenile Hatchery Spring Chinook Salmon and Coho Salmon Does Not Alter Adult Survivals
Authors: Tipping Jack M
Published: June 2008

The feeding rate of juvenile spring Chinook salmon Oncorhynchus tshawytscha and coho salmon O. kisutch was substantially reduced in winter and substantially increased in spring in an attempt to increase postrelease survivals. All groups were coded-wire-tagged, and the experiment was replicated for 3 years. Although feed savings were sometimes realized, the results showed no significant difference in adult survival rates among hatchery returns, as determined by tag recoveries in fisheries, and spawning bed recoveries for the years examined.
Density and Shelter Influence the Adaptation of Wild Juvenile Cauque Prawns Macrobrachium americanum to Culture Conditions
Authors: García-Guerrero Marcelo U , Apun-Molina Juan Pablo
Published: June 2008

Consumer demand for aquatic animals has led to increased interest in using new species for aquaculture purposes. This study appraises the potential for aquaculture of the cauque prawn Macrobrachium americanum using wild juveniles from the west coast of Mexico. Four treatments were applied; treatments A and B consisted of 196 prawns/m2 and treatments C and D of 98 prawns/m2, with and without shelter, respectively. Growth and survival under these conditions were examined for 84 d. The combination of 98 prawns/m2 and shelter resulted in the best survival and growth, whereas the poorest performance was in the treatment with 196 prawns/m2 and no shelter.
Growth and Feed Efficiency of Juvenile Channel Catfish Reared at Different Water Temperatures and Fed Diets Containing Various Levels of Fish Meal
Authors: Li Menghe H , Robinson Edwin H , Peterson Brian C , Bates Terry D
Published: June 2008

Channel catfish Ictalurus punctatus do not feed well at low temperatures. It is generally thought that a diet containing fish meal enhances feed palatability at low temperatures since fish meal is highly palatable to fish. There is a lack of information on the effects of fish meal levels on the growth performance of channel catfish reared at low temperatures. Therefore, a study was conducted in a recirculating system to examine the effects of fish meal levels on the feed consumption, weight gain, and feed efficiency of juvenile channel catfish reared at various temperatures. Fish with an initial weight of 9.6 ± 0.1 g were stocked in 23-L clear polycarbonate tanks maintained at approximately 17, 21, or 27 °C. The fish were fed with diets containing 0, 4, or 8% menhaden Brevoortia spp. fish meal for 9 weeks. There was a significant interaction between water temperature and fish meal level with respect to weight gain. At 27°C, fish fed diets containing 4% and 8% fish meal gained significantly more weight than fish fed the all-plant-protein diet. However, the level of fish meal had no significant effect on the weight gain of fish at 17°C or 21°C. This suggests that the olfactory and gustatory responses of channel catfish to fish meal (up to 8% in the diet) may not be as sensitive at low temperatures as at optimum temperatures. The results also indicate that more than 4% fish meal in the diet is not beneficial for the optimum growth and feed efficiency of channel catfish fingerlings raised at 27°C.
Huntington’s Disease: A Caring Approach to the End of Life
Authors: Klager Joseph , Duckett Ayana , Sandler Susan , Moskowitz Carol
Published: June 2008

This article describes the challenges of end-of-life care encountered in a specialized long-term care program for people with Huntington’s disease (HD). The Promoting Excellence in End-of-Life Care Huntington’s Disease Workgroup defines the initiation of palliative care as the point at which independent living is no longer possible. Mobility and lifestyle accommodations for people in the nursing home setting with an early-onset disease are a major feature of this program. The primary end-of-life considerations are advance directives decision-making and anticipating end-stage care needs. Disease progression, denial, family conflict, and clinician blind-spots may impede the development of timely advance directives. The unpredictable and idiosyncratic nature of disease progression impacts decision making for end-of-life care settings and approaches: hospitalization, nursing home stay, and in-house hospice care are the available options. The Workgroup has delineated several priority areas for patient care in HD: autonomy; dignity; meaningful social interaction; communication; comfort; safety and order; spirituality; enjoyment, entertainment, and well-being nutrition; and functional competence. This review also includes a description of the program features in each of these areas.
Group Homes for Elders With Dementia in Japan
Authors: Traphagan John W. , Nagasawa Tomoko
Published: June 2008

In this article we explore the development of group homes for elders with dementia in Japan since the inception of the long-term care insurance program in 2000. We suggest that the combination of demographic and policy trends in recent years have created a context in which entrepreneurial activities related to elder care have increased significantly. By focusing on one of the new institutions that has emerged, we show one way in which social policy has had a significant influence on the lives of elders suffering from dementia and their families. Finally, we point out some of the problems that have arisen along with the growth of these new forms of care, such as a lack of involvement by family members in visiting and caring for elders.
Use of multichannel electrointestinography for noninvasive assessment of myoelectrical activity in the cecum and large colon of horses
Authors: Koenig Judith B. , Martin Christina E. W. , Nykamp Stephanie G. , Mintchev Martin P.
Published: June 2008

Objective—To evaluate whether changes in myoelectrical activity in the cecum and large colon of horses can be detected via multichannel electrointestinography (EIG).

Animals—6 healthy mature horses.

Procedures—Each horse underwent 3 EIG procedures. Intestinal myoelectrical activity (cecum and large colon) was recorded during a 20-minute period following IV administration of physiologic saline (0.9% NaCl) solution (20 mL; baseline), erythromycin lactobionate (0.5 mg/kg), or detomidine (0.015 mg/kg); intestinal contractions were concurrently viewed via B-mode ultrasonography. By use of computer software, 8-channel EIG recordings were analyzed and the mean of the dominant frequency (a measure of the rhythmicity of gastric electrical activity) expressed in cycles per minute (cpm) was obtained. Total power (MV2) was calculated, and treatment effect was expressed as the power ratio (ie, treatment-associated power divided by the baseline power).

Results—The dominant frequency cpm values were not stable, and no significant differences between treatments were detected. Compared with the effects of saline solution treatment, detomidine significantly reduced the mean cecal and colonic power ratios. Erythromycin significantly reduced the cecal power ratio and increased the colonic power ratio, although the increase was significant in only 1 channel. Ultrasonographic findings and total power (predominantly from the long-distance electrode pairs) were significantly correlated.

Conclusions and Clinical Relevance—In horses, EIG was useful for assessment of changes in myoelectrical activity in the cecum and large colon. Multiple electrodes should be used to cover a larger area of the intestine, and agreement between multiple channels is needed to make the analysis meaningful.
Pharmacokinetics of buprenorphine following intravenous administration in dogs
Authors: Krotscheck Ursula , Boothe Dawn M. , Little Amy A.
Published: June 2008

Objective—To determine pharmacokinetics of buprenorphine in dogs after IV administration.

Animals—6 healthy adult dogs.

Procedures—6 dogs received buprenorphine at 0.015 mg/kg, IV. Blood samples were collected at time 0 prior to drug administration and at 2, 5, 10, 15, 20, 30, 40, 60, 90, 120, 180, 240, 360, 540, 720, 1,080, and 1,440 minutes after drug administration. Serum buprenorphine concentrations were determined by use of double-antibody radioimmunoassay. Data were subjected to noncompartmental analysis with area under the time-concentration curve to infinity (AUC) and area under the first moment curve calculated to infinity by use of a log-linear trapezoidal model. Other kinetic variables included terminal rate constant (kel) and elimination half-life (t1/2), plasma clearance (Cl), volume of distribution at steady state (Vdss), and mean residence time (MRT). Time to maximal concentration (Tmax) and maximal serum concentration (Cmax) were measured.

Results—Median (range) values for Tmax and MRT were 2 minutes (2 to 5 minutes) and 264 minutes (199 to 600 minutes), respectively. Harmonic mean and pseudo SD for t1/2 were 270 ± 130 minutes; mean ± SD values for remaining pharmacokinetic variables were as follows: Cmax, 14 ± 2.6 ng/mL; AUC, 3,082 ± 1,047 ng•min/mL; Vdss, 1.59 ± 0.285 L/kg; Cl, 5.4 ± 1.9 mL/min/kg; and, kel, 0.0026 ± 0.0,012.

Conclusions and Clinical Relevance—Pharmacokinetic variables of buprenorphine reported here differed from those previously reported for dogs. Wide variations in individual t1/2 values suggested that dosing intervals be based on assessment of pain status rather than prescribed dosing intervals.
Effects of head-down positioning on regional central nervous system perfusion in isoflurane-anesthetized horses
Authors: Brosnan Robert J. , Esteller-Vico Alejandro , Steffey Eugene P. , LeCouteur Richard A. , Liu Irwin K. M. , Vaughan Betsy
Published: June 2008

Objective—To test the hypothesis that head-down positioning in anesthetized horses increases intracranial pressure (ICP) and decreases cerebral and spinal cord blood flows.

Animals—6 adult horses.

Procedures—For each horse, anesthesia was induced with ketamine hydrochloride and xylazine hydrochloride and maintained with 1.57% isoflurane in oxygen. Once in right lateral recumbency, horses were ventilated to maintain normocapnia. An ICP transducer was placed in the subarachnoid space, and catheters were placed in the left cardiac ventricle and in multiple vessels. Blood flow measurements were made by use of a fluorescent microsphere technique while each horse was in horizontal and head-down positions. Inferential statistical analyses were performed via repeated-measures ANOVA and Dunn-Sidak comparisons.

Results—Because 1 horse developed extreme hypotension, data from 5 horses were analyzed. During head-down positioning, mean ± SEM ICP increased to 55 ± 2 mm Hg, compared with 31 ± 2 mm Hg during horizontal positioning; cerebral perfusion pressure was unchanged. Compared with findings during horizontal positioning, blood flow to the cerebrum, cerebellum, and cranial portion of the brainstem decreased significantly by approximately 20% during head-down positioning; blood flows within the pons and medulla were mildly but not significantly decreased. Spinal cord blood flow was low (9 mL/min/100 g of tissue) and unaffected by position.

Conclusions and Clinical Relevance—Head-down positioning increased heart-brain hydrostatic gradients in isoflurane-anesthetized horses, thereby decreasing cerebral blood flow and, to a greater extent, increasing ICP. During anesthesia, CNS regions with low blood flows in horses may be predisposed to ischemic injury induced by high ICP.
Hematologic effects of subcutaneous administration of recombinant human granulocyte colony-stimulating factor (filgrastim) in healthy alpacas
Authors: McKenzie Erica C. , Tornquist Susan J. , Gorman M. Elena , Cebra Christopher K. , Payton Mark E.
Published: June 2008

Objective—To determine the effects of SC administration of filgrastim on cell counts in venous blood and bone marrow of healthy adult alpacas.

Animals—10 healthy alpacas.

Procedures—Alpacas were randomly assigned to receive treatment with filgrastim (5 μg/ kg, SC; n = 5) or an equivalent volume of physiologic saline (0.9% NaCl) solution (5) once a day for 3 days. Blood samples were obtained via jugular venipuncture 1 day prior to treatment and once a day for 5 days commencing 24 hours after the first dose was administered. Complete blood counts were performed for each blood sample. Bone marrow aspirates were obtained from the sternum of each alpaca 48 hours before the first treatment was administered and 72 hours after the third treatment was administered. Myeloid-to-erythroid cell (M:E) ratio was determined via cytologic evaluation of bone marrow aspirates.

Results—In filgrastim-treated alpacas, substantial increases in counts of WBCs and neutrophils were detected within 24 hours after the first dose was administered. Band cell count and percentage significantly increased 24 hours after the second dose. Counts of WBCs, neutrophils, and band cells remained high 48 hours after the third dose. Red blood cell counts and PCV were unaffected. The M:E ratio also increased significantly after treatment with filgrastim.

Conclusions and Clinical Relevance—Filgrastim induced rapid and substantial increases in numbers of circulating neutrophils and M:E ratios of bone marrow in healthy alpacas. Therefore, filgrastim may be useful in the treatment of camelids with impaired bone marrow function.
Ultrasonographic examination of the omasum, liver, and small and large intestines in cows with right displacement of the abomasum and abomasal volvulus
Authors: Braun Ueli , Feller Bernhard , Hässig Michael , Nuss Karl
Published: June 2008

Objective—To describe ultrasonographic appearance of the liver, small and large intestines, and omasum in cows with right displacement of the abomasum (RDA) and with abomasal volvulus (AV) and to determine whether RDA and AV can be differentiated on the basis of ultrasonographic findings.

Animals—17 cows with RDA, 9 cows with AV, and 10 healthy control cows.

Procedures—A linear transducer was used to examine the abomasum, liver, omasum, and small and large intestines from the right side.

Results—The liver was imaged less frequently in cows with RDA or AV, compared with control cows. In 9 cows with RDA or AV, the liver could not be imaged. The small intestine was imaged less frequently in cows with RDA or AV than in control cows; in cows with AV, the small intestine could not be imaged in the 8th, 9th, or 10th intercostal space. The large intestine was imaged less frequently in the 11th and 12th intercostal spaces and the cranial region of the flank in cows with RDA or AV. The omasum was also imaged less frequently in the 8th and 9th intercostal spaces in cows with RDA or AV. Cows with RDA or AV could not be differentiated on the basis of ultrasonographic findings.

Conclusions and Clinical Relevance—Compared with control cows, cows with RDA and AV had changes in positioning and therefore extent of ultrasonographic imaging of the liver, omasum, and small and large intestines; however, these findings were not useful in differentiating between cows with RDA and AV.
Effects of the second-generation synthetic lipid A analogue E5564 on responses to endotoxin equine whole blood and monocytes
Authors: Figueiredo Monica D. , Moore James N. , Vandenplas Michel L. , Sun Wan-chun , Murray Thomas F.
Published: June 2008

Objective—To evaluate proinflammatory effects of the second-generation synthetic lipid A analogue E5564 on equine whole blood and isolated monocytes and to determine the ability of E5564 to prevent LPS (lipopolysaccharide)-induced procoagulant activity (PCA); tumor necrosis factor (TNF)-α production; and mRNA expression of TNF-α, interleukin (IL)-1β, IL-6, and IL-10 by equine monocytes.

Sample Population—Venous blood samples obtained from 19 healthy horses.

Procedures—Whole blood and monocytes were incubated with Escherichia coli O111:B4 LPS, E5564, or E5564 plus E coli O111:B4 LPS. Whole blood and cell supernatants were assayed for TNF-α, and cell lysates were assayed to determine PCA. Expression of mRNA for TNF-α, IL-1β, IL-6, and IL-10 by monocytes was determined by use of real-time quantitative PCR assay.

Results—Minimal proinflammatory effects were detected in whole blood and monocytes. In addition, E5564 inhibited LPS-induced PCA and TNF-α production in a concentration-dependent manner. Furthermore, E5564 significantly inhibited LPS-induced mRNA expression of TNF-α, IL-1β, and IL-10 and decreased LPS-induced expression of IL-6.

Conclusions and Clinical Relevance—The second-generation synthetic lipid A analogue E5564 lacked agonist activity in equine whole blood and monocytes and was a potent antagonist of enteric LPS. Therefore, E5564 appeared to be the first lipid A analogue that has potential as an effective therapeutic agent in horses with endotoxemia.
Effect of suckling an isotonic solution of sodium acetate, sodium bicarbonate, or sodium chloride on abomasal emptying rate and luminal pH in calves
Authors: Marshall Tessa S. , Constable Peter D. , Crochik Sonia S. , Wittek Thomas , Freeman David E. , Morin Dawn E.
Published: June 2008

Objectives—To compare abomasal emptying rates in calves after suckling milk replacer or 3 common orally administered electrolyte solution components.

Animals—5 male calves < 35 days of age.

Procedures—Calves with a cannula fitted in the abomasal body were fed 2 L of milk replacer with or without parenteral administration of atropine (0.01 mg/kg, IV, then 0.02 mg/ kg, SC, q 30 min) or isotonic (150mM) solutions of sodium acetate, NaHCO3, or NaCl in a randomized crossover design. Abomasal emptying rates were determined via scintigraphy, acetaminophen absorption, ultrasonography, and change in abomasal luminal pH.

Results—Scintigraphic half-emptying time, time of maximal plasma acetaminophen concentration, ultrasonographic half-emptying time, and pH return time indicated similar abomasal emptying rates following suckling of isotonic sodium acetate, NaHCO3, and NaCl solutions, whereas the emptying rate of milk replacer was significantly slower. Mean maximal abomasal luminal pH was highest following suckling of NaHCO3 (pHmax = 7.85) and lowest following suckling of NaCl (pHmax = 4.52); sodium acetate (pHmax = 6.59) and milk replacer (pHmax = 5.84) yielded intermediate pH values.

Conclusions and Clinical Relevance—Isotonic solutions of sodium acetate, NaHCO3, and NaCl were rapidly emptied from the abomasum but varied markedly in their ability to alkalinize the abomasum. Sodium bicarbonate–containing orally administered electrolyte solution might increase the frequency of infection or severity of clinical disease in diarrheic calves treated for dehydration by causing prolonged abomasal alkalinization.
Evaluation of associations between lifetime exposure to drinking water disinfection by-products and bladder cancer in dogs
Authors: Backer Lorraine C. , Coss Angela M. , Wolkin Amy F. , Flanders W. Dana , Reif John S.
Published: June 2008

Objective—To assess the risk of bladder cancer in dogs from exposure to drinking water disinfection by-products and determine whether dogs could serve as sentinels for human bladder cancer associated with such exposures.

Design—Case-control study.

Animals—100 dogs with cancer of the urinary bladder and 100 control dogs.

Procedures—Case and control dogs were frequency-matched by age (within 2 years) and sex. Owners of dogs enrolled provided verbal informed consent and were interviewed by telephone. The telephone questionnaire included a complete residence history for each dog. Each dog's total exposure history to trihalomethanes was reconstructed from its residence history and corresponding drinking water utility company data.

Results—No association was detected between increasing years of exposure to chlorinated drinking water and risk of bladder cancer. Dogs with bladder cancer were exposed to higher total trihalomethanes concentrations than control dogs; however, the difference was not significant.

Conclusions and Clinical Relevance—Although humans and their dogs live in the same household, the activity patterns of dogs may lead to lower exposures to household tap water. Thus, although exposure to disinfection by-products in tap water may be a risk factor for human bladder cancer, this may not be true for canine bladder cancer at the concentrations at which dogs are exposed.
Assessment of serum antibody titers against canine distemper virus, canine adenovirus type II, and canine parvovirus in Alaskan sled dogs before and after a long-distance race
Authors: Banse Heidi E. , McKenzie Erica C. , Nelson Stuart , Hinchcliff Kenneth W.
Published: June 2008

Objective—To determine serum antibody titers against canine distemper virus (CDV), canine adenovirus type II (CAV-2), and canine parvovirus (CPV) in trained sled dogs prior to and after completion of a long-distance race.

Design—Prospective cohort study.

Animals—195 Alaskan sled dogs (from 18 kennels) that participated in the 2006 Iditarod Trail Race.

Procedures—All 1,323 dogs participating in the race had been vaccinated against the 3 viruses at 19 to 286 days prior to initial blood sample collection (obtained within the month preceding the race). Within 12 hours of race completion, blood samples were collected from 195 dogs (convenience sample) and matched with each dog's prerace sample. Serum antibody titers (90% confidence intervals [CIs]) were determined via serum neutralization assays.

Results—After racing, geometric mean titers against CDV and CPV were significantly higher (2,495 [90% CI, 321 to 16,384] and 6,323 [90% CI, 512 to 32,768], respectively) than prerace values (82 [90% CI, 11 to 362] and 166 [90% CI, 32 to 1,024], respectively). Sixty-one of 194 (31.4%) dogs had t 4-fold increases in anti-CPV antibody titers after racing. Prerace serum antibody titers against CDV, CPV, and CAV-2 varied significantly by sled team but were not associated with time since vaccination.

Conclusions and Clinical Relevance—Postrace increases in serum anti-CDV and anti-CPV antibody titer might reflect exposure of dogs to these agents immediately before or during racing. Dogs had no clinical signs of CDV-, CAV-2-, or CPV-associated disease; therefore, the clinical importance of these titer changes is uncertain.
Evaluation of circulating amino terminal-pro-B-type natriuretic peptide concentration in dogs with respiratory distress attributable to congestive heart failure or primary pulmonary disease
Authors: Fine Deborah M. , DeClue Amy E. , Reinero Carol R.
Published: June 2008

Objective—To evaluate assessment of circulating amino terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration as a means to discriminate between congestive heart failure and primary pulmonary disease in dogs.

Design—Prospective case series.

Animals—46 dogs with signs of respiratory distress or coughing.

Procedures—All dogs underwent physical and thoracic radiographic examinations. Dogs with evidence of heart disease (eg, murmur, arrhythmia, or large cardiac silhouette detected by radiography) also underwent echocardiography. Dogs with no evidence of heart disease or failure were included if they underwent bronchoalveolar lavage (with cytologic examination and bacterial culture of the lavage fluid). Blood samples for NT-proBNP assay were obtained within 12 hours of the diagnosis of heart failure or prior to bronchoalveolar lavage in dogs with primary pulmonary disease. Circulating concentrations of NT-proBNP were compared between groups and correlated with radiographic and echocardiographic measures of cardiac size.

Results—Congestive heart failure and primary pulmonary disease were diagnosed in 25 and 21 dogs, respectively. Dogs with congestive heart failure had significantly higher median serum or plasma NT-proBNP concentration (2,554 pmol/L; interquartile [25% to 75%] range, 1,651.5 to 3,475.5 pmol/L) than dogs with primary pulmonary disease (357 pmol/L; interquartile range, 192.5 to 565.5 pmol/L). Radiographic vertebral heart score and echocardiographic left atrial-to-aortic diameter ratio were not correlated with NT-proBNP concentration. Left ventricular end-diastolic diameter (measured echocardiographically) and NT-proBNP concentration were weakly correlated.

Conclusions and Clinical Relevance—Serum or plasma NT-proBNP concentration assessment may be useful for discrimination of congestive heart failure from primary pulmonary disease in dogs with respiratory distress or cough.
Use of laser lithotripsy for fragmentation of uroliths in dogs: 73 cases (2005–2006)
Authors: Adams Larry G. , Berent Allyson C. , Moore George E. , Bagley Demetrius H.
Published: June 2008

Objective—To describe use of transurethral cystoscope–guided laser lithotripsy for fragmentation of cystic and urethral uroliths and determine procedure duration and short-term and long-term outcome in dogs.

Design—Retrospective case series.

Animals—73 dogs with naturally occurring uroliths in the urinary bladder, urethra, or both.

Procedures—Transurethral cystoscope–guided laser lithotripsy was performed in all dogs, and medical records were reviewed for short-term and long-term outcome and complications.

Results—Laser lithotripsy resulted in complete fragmentation of all uroliths in all 28 female dogs and a majority of male dogs (39/45 [86.7%]). Dogs with urethroliths had shorter median laser time than dogs with cystic uroliths. Basket extraction and voiding urohydro-propulsion were successful for removal of the urolith fragments following laser lithotripsy. Complications related to cystoscope-guided laser lithotripsy occurred in 5 of 28 (17.9%) female dogs and 6 of 45 (13.3%) male dogs.

Conclusions and Clinical Relevance—Transurethral cystoscope–guided laser lithotripsy was successful in female dogs and most male dogs for fragmentation of cystic and urethral uroliths. Short-term complications were most commonly related to urethral swelling and resolved with placement of an indwelling urinary catheter. There were no long-term complications.
Chronic pancreatitis with secondary diabetes mellitus treated by use of insulin in an adult California sea lion
Authors: Meegan Jenny M. , Sidor Inga F. , Steiner Jörg M. , Sarran Delphine , Dunn J. Lawrence
Published: June 2008

Case Description—A 21-year-old neutered male captive California sea lion developed chronic polyuria; polydipsia; polyphagia; accelerated development of existing cataracts; and frequent episodes of gastrointestinal upset including anorexia, signs of abdominal discomfort, diarrhea, and vomiting.

Clinical Findings—Chronic hypercholesterolemia, hypertriglyceridemia, hyperglycemia, and glucosuria were identified. During episodes of gastrointestinal abnormalities, transient hyperbilirubinemia and increased serum γ-glutamyltransferase activities developed. Clinical findings strongly suggested chronic pancreatitis with secondary diabetes mellitus and intermittent cholestasis. Multiple diagnostic tests, including abdominal ultrasonography, serial hematologic and serum biochemical analyses, fecal examinations, urinalyses and bacteriologic culture of urine, measurement of serum fructosamine and insulin concentrations, and evaluation of thyroid and adrenal function, did not reveal any specific parasitic, endocrine, hepatic, or neoplastic etiologies.

Treatment and Outcome—For 1.5 years, the sea lion received once-daily administration of glargine insulin, gastrointestinal protectants, and a strict high-protein, low-fat diet. Daily monitoring of glucose regulation was achieved by training the sea lion to submit to blood and urine sampling. Glucose regulation ranged from fair to good, and clinical signs of diabetes mellitus lessened. Episodes of gastrointestinal upset still occurred, although the frequency and severity decreased. Ultimately, a severe episode developed, associated with diabetic ketoacidosis and sepsis, and the sea lion died. Severe fibrosing pancreatitis with exocrine and endocrine atrophy and abscesses arising from ectatic pancreatic ducts were found. Peripancreatic fibrosis caused stricture of the common bile duct, resulting in gallbladder distension without cholecystitis.

Clinical Relevance—Diabetes mellitus can occur secondary to chronic pancreatitis in California sea lions and insulin therapy should be considered.
Who Is Given Tests in What Language by Whom, When, and Where? The Need for Probabilistic Views of Language in the Testing of English Language Learners
Authors: Solano-Flores Guillermo
Published: June 2008

The testing of English language learners (ELLs) is, to a large extent, a random process because of poor implementation and factors that are uncertain or beyond control. Yet current testing practices and policies appear to be based on deterministic views of language and linguistic groups and erroneous assumptions about the capacity of assessment systems to serve ELLs. The question Who is given tests in what language by whom, when, and where? provides a conceptual framework for examining testing as a communication process between assessment systems and ELLs. Probabilistic approaches based on generalizability theory—a psychometric theory of measurement error—allow examination of the extent to which assessment systems’ inability to effectively communicate with ELLs affects the dependability of academic achievement measures.
Supraciliary keyhole craniotomy for brain abscess debridement
Authors: Noggle Joseph C. , Sciubba Daniel M. , Nelson Clarke , Garcés-Ambrossi Giannina L. , Ahn Edward , Jallo George I.
Published: June 2008

Object

Treatments for brain abscesses have typically involved invasive craniotomies followed by debridement. These methods often require large incisions with vast exposure and may be associated with high morbidity rates. For supraorbital lesions of the anterior and middle cranial fossa, minimally invasive craniotomies may limit exposure and decrease surgically related morbidity while allowing adequate debridement and decompression. The authors report their experience in treating frontal epidural abscesses in pediatric patients through minimally invasive supraciliary craniotomies over a 4-year period.

Methods

Three pediatric patients with frontal epidural abscesses underwent minimally invasive debridement procedures. Each procedure consisted of a supraciliary incision and a small craniotomy to expose the abscess. All patients underwent pre- and postoperative radiological evaluation including computed tomography and magnetic resonance imaging. Data were collected on preoperative characteristics, operative management, and postoperative outcomes.

Results

Two patients were male and 1 patient was female. The ages of the patients ranged from 6 to 10 years (mean 8 years). A frontal abscess was diagnosed in all patients, and all were treated surgically without perioperative complications. Microbes cultured postoperatively included methicillin-resistant Staphylococcus aureus in 2 patients and Staphylococcus viridans in 1 patient. The mean follow-up duration was 12.3 months. No neurological or vascular complications were noted during follow-up. All patients were treated with antibiotics postoperatively and experienced resolution of symptoms and excellent outcomes.

Conclusions

Frontal epidural abscesses can be adequately and safely debrided via a minimally invasive supraciliary craniotomy. This approach has a cosmetic benefit and may decrease approach-related morbidity.