Laser-induced chemistry for microelectronics

Laser-controlled chemical reactions are being explored for use in all phases of the processing of semiconductor devices. Laser-induced chemical processing can produce submicrometer features without the aid of photolithography. Research is also providing new information on light-excited and light-enhanced interface reactions.     

Failure of copper or vitamin D supplements to affect the dental condition of young sheep on two Wairarapa farms

Regular injections of copper or vitamin D had no overall effect on growth rate, fleece weight, or the amount of wear of the central incisor teeth of sheep on two Wairarapa farms over 26 months. The greatest amount of tooth wear occurred during the period when soil ingestion (measured by acid-insoluble residue, titanium or aluminium in the faeces) was also greatest. Various indicators of copper, calcium or nutritional status were measured in the blood of control sheep and those receiving vitamin D or copper. At no sampling time was there a significant difference for any of these between groups on either farm. Pasture samples were analysed regularly for calcium, cobalt, copper, magnesium, manganese, molybdenum, phosphorus, sulphur, zinc and percentage ash. At most times values were, on the basis of existing criteria, considered normal. Although the pasture calcium/phosphorus ratio fell below one on several occasions this did not result in a change in plasma calcium or phosphorus levels. On the basis of criteria established for pen-fed sheep, dietary available copper levels on both farms were considered low for much of the time. However, liver and blood copper values were adequate at alI times.     

Effects of the second-generation synthetic lipid A analogue E5564 on responses to endotoxin in [corrected] equine whole blood and monocytes

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)-alpha production; and mRNA expression of TNF-alpha, interleukin (IL)-1beta, 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-alpha, and cell lysates were assayed to determine PCA. Expression of mRNA for TNF-alpha, IL-1beta, 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-alpha production in a concentration-dependent manner. Furthermore, E5564 significantly inhibited LPS-induced mRNA expression of TNF-alpha, IL-1beta, 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.     

Imaging the pore structure of geomaterials

Laser scanning confocal microscopy can be used to image the pore structure of geologic materials in three dimensions at a resolution of 200 nanometers. The technique involves impregnation of the void space with an epoxy doped with a fluorochrome whose fluorescent wavelength matches the excitation wavelength. Optical sections with a thickness of less than 1 micrometer can be sliced from thick polished sections and combined to produce three-dimensional reconstructions. Application of the technique to rocks with porosities from 1 to 20 percent reveals the geometric complexity of the pore space. The technique can also be applied to other brittle solids such as ceramics.     

A tissue culture system to study respiratory ciliary epithelial adherence of selected swine mycoplasmas

An in vitro culture system for swine tracheal epithelial cells was developed to study the adherence of swine mycoplasmas. Swine tracheal epithelial cells were isolated by enzymatic digestion and cultured on microporous membranes. Growth medium was placed under the membrane support to create air-liquid interface feeding resulting in the cells growing cilia and microvilli on the apical surface. Two strains of Mycoplasma hyopneumoniae (pathogenic strain 91-3 and non-pathogenic type strain J) and two strains of Mycoplasma flocculare (type strain Ms42 and field isolate 7160T) were used in this study. The morphology of the cultured tracheal cells was evaluated by transmission electron microscopy. Adherence of M. hyopneumoniae and M. flocculare and damage to the cilia were demonstrated using scanning electron microscopy. The pathogenic M. hyopneumoniae strain 91-3 adhered to cilia inducing obvious damage. The non-pathogenic M. hyopneumoniae strain J did not adhere to mature cilia. Both M. flocculare strains Ms42 and 7160T adhered to mature and budding cilia. No obvious ciliary damage was observed with strain Ms42. Minimal damage consisting of a slight tangling of the cilia occurred after adherence by strain 7160T. This model will enable us to further study the role of adherence of mycoplasmas on the pathogenesis of swine pneumonia.     

Dorsolateral approach for arthrocentesis of the centrodistal joint in horses

OBJECTIVE: To develop a dorsolateral approach to the centrodistal (distal intertarsal) joint in horses and compare its success rate with that of the traditional medial approach in that joint. SAMPLE POPULATION: 25 cadaveric equine hind limbs, ultrasonographic images, and radiographic views of the tarsal region of 5 and 59 healthy horses, respectively, and 22 horses with a clinical indication for centrodistal joint centesis. PROCEDURES: The dorsolateral approach was established anatomically (3 cadaveric limbs), ultrasonographically (5 horses), and radiographically (59 horses). Centrodistal joint arthrocentesis was performed in 22 cadaveric hind limbs and 22 horses; the number of needle repositionings required for procedure completion via the medial (in vitro) and the dorsolateral approach (in vitro and in vivo) was determined. RESULTS: For the dorsolateral approach to the centrodistal joint, the injection site was 2 to 3 mm lateral to the long digital extensor tendon and 6 to 8 mm proximal to a line drawn perpendicular to the axis of the third metatarsal bone through the proximal end of the fourth metatarsal bone. The needle was directed plantaromedially (angle of approx 70 degrees from the sagittal plane). The number of needle repositionings required to complete centrodistal joint centesis via the dorsolateral and medial approaches was not significantly different. CONCLUSION AND CLINICAL RELEVANCE: In a clinical setting, the dorsolateral approach to the centrodistal joint in horses appears to have some advantages over the traditional medial approach. The success rate of arthrocentesis was similar via either approach, and palpation of the anatomic landmarks was easy.     

Pharmacologic characterization of novel adenosine A2A receptor agonists in equine neutrophils

OBJECTIVE: To evaluate anti-inflammatory effects of several novel adenosine receptor agonists and to determine their specificity for various adenosine receptor subtypes on neutrophils, cells heterologously expressing equine adenosine receptors, or equine brain membranes. SAMPLE POPULATION: Neutrophils isolated from 8 healthy horses. PROCEDURES: Radioligand binding experiments were performed to compare binding affinities of adenosine receptor agonists to equine adenosine A(1), A(2A), and A(3) receptor subtypes. Effects of these agonists on endotoxin-induced production of reactive oxygen species (ROS) by equine neutrophils and roles of specific adenosine receptor subtypes and cAMP production in mediating these effects were determined. RESULTS: Radioligand binding experiments yielded a ranked order of affinity for the brain equine A(2A) receptor on the basis of 50% inhibitory concentrations (IC(50)) of the agonists as follows: ATL307 (IC(50) = 1.9nM) and ATL313 > ATL309 and ATL310 > ATL202 > 2-([p-2- carboxyethyl] phenylethylamino)-5'-N-ethylcarboxyamidoadenosine > 5'-N-ethylcarboxamidoadenosine. Furthermore, ATL313 had approximately 100-fold greater selectivity for A(2A) over A(1) and A(3) receptors. In functional assays with equine neutrophils, the compounds inhibited endotoxin-induced ROS production and stimulated production of cAMP with the same ranked order of potency. Results of experiments performed with selective adenosine receptor antagonists indicated that functional effects of ATL313 were via stimulation of A(2A) receptors. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that activation of A(2A) receptors exerted anti-inflammatory effects on equine neutrophils and that stable, highly selective adenosine A(2A) receptor agonists may be developed for use in management of horses and other domestic animals with septic and nonseptic inflammatory diseases.     

Use of condensed tannin extract from quebracho trees to reduce methane emissions from cattle

Our objective was to determine if condensed tannin extract from quebracho trees (Schinopsis quebracho-colorado; red quebracho) could be used to reduce enteric methane emissions from cattle. The experiment was designed as a repeated 3 x 3 Latin square (4 squares) with 3 treatments (0, 1, and 2% of dietary DM as quebracho tannin extract) and 3 28-d periods. Six spayed Angus heifers (238 +/- 13.3 kg of initial BW) and 6 Angus steers (207 +/- 8.2 kg of initial BW) were each assigned to 2 squares. The measured condensed tannin content of the extract was 91%, and the basal diet contained 70% forage (DM basis). Feeding quebracho tannin extract had no effect on BW, ADG, or nutrient intakes. Furthermore, it had no effect on DM, energy, or fiber (ADF and NDF) digestibility, but apparent digestibility of CP decreased linearly (P < 0.001) by 5 and 15% with 1 and 2% quebracho tannin extract, respectively. There were no effects of quebracho tannin extract on methane emissions (g/d, g/kg of DM, % of GE intake, or % of DE intake). Feeding up to 2% of the dietary DM as quebracho tannin extract failed to reduce enteric methane emissions from growing cattle, although the protein-binding effect of the quebracho tannin extract was evident.     

Technical note: A system for continuous recording of ruminal pH in cattle

Continuous recording of ruminal pH in cannulated cattle has been practiced to study rumen metabolism. However, most systems reported did not permit animal mobility during pH recording. Therefore, the objective of this study was to develop a continuous rumen pH data acquisition system that permitted animal mobility during data acquisition. A further objective was to compare the pH readings obtained using the continuous recording system to readings obtained at the same time using spot sampling. The continuous recording system was composed of a heavy-duty electrode and a data logger. The electrode was attached to a 0.5-kg weight to help maintain the electrode in the ventral sac of the rumen. The electrode was connected via a 0.5-m cable to a lightweight data logger that was mounted on the animal's back using a belt wrapped around the girth. The data logger was battery powered and could hold over 13,000 pH data values. A personal digital assistant was used to configure and download data from the data logger during the experiment. Ruminal pH was continuously recorded (every 10 s) using a dry Holstein cow fed alfalfa hay ad libitum in a 3-d experiment to compare the performance of the continuous system to spot samples taken from the ventral sac of the rumen, the same location as the continuous electrode. The spot samples were collected 3 times per d for 3 d. At every sampling time, 3 replicate samples were collected, pH was determined immediately using a handheld pH meter, and readings were averaged (n = 3) and compared with the average of the 3 pH readings recorded using the continuous system at the same time. The pH recorded by spot sampling (6.63 +/- 0.04) was greater (P = 0.009) than that of the continuous system (6.56 +/- 0.03), with a correlation of r = 0.88 (P = 0.002). The continuous recording system has the potential to facilitate measurement of ruminal pH in free-roaming cattle.