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Jugular blood samples were collected at 4 h intervals from six mares during an oestrous cycle to study the hormonal events that occur around the time of luteolysis. Blood samples from day 10 (day 0 = ovulation) until day 3 of oestrus were assayed for prostaglandin metabolite 13,14-dihydro-15-keto PGF2alpha (PGFM), oxytocin, prolactin, progesterone and oestrogen conjugates. PGF2alpha (0.5 or 1.5 mg) was administered to six mid-dioestrous mares and the oxytocin and prolactin responses were measured. One to five large (peakor =2 x nadir) pulses of PGFM, oxytocin and prolactin were detected in mares during the 3 day period starting on day 13 +/- 0.5. The first PGFM pulse was preceded or accompanied by one or more oxytocin pulses and, overall, large PGFM and oxytocin pulses occurred coincidentally (P0.001). During the period of oxytocin and PGFM pulses, progesterone concentrations decreased (P0.001) from mid-dioestrous to oestrous values. The first large prolactin pulse occurred as progesterone concentrations approached the nadir and preceded an increase in oestrogen conjugate concentrations by 1.9 +/- 0.6 days. Both PGF2alpha doses significantly increased prolactin concentrations, whereas only the larger dose increased oxytocin concentrations. It is concluded that in mares: (i) PGFM and oxytocin secretion patterns are consistent with the ruminant model of the initiation of luteolysis, in which pulsatile secretion of oxytocin from the posterior pituitary triggers episodic release of uterine PGF2alpha; and (ii) the timing of large prolactin pulses in relation to progesterone and oestrogen conjugates changes indicates that prolactin is more likely to have a role in follicular maturation than in luteolysis.

We report on the control of zinc in organometallic vapor phase epitaxial (OMVPE) grown InP:Zn/InGaAs/InPp- i- n double heterojunctions with InGaAs:Zn contacting layers. As a function of diethylzinc (DEZn) flow, we measure net acceptor concentrations for the InP:Zn p-layer in the range 2 × 1017≤N a−N d≤ 9 × 1017 cm−3. A 435°C post-growth anneal for 300 sec increases the net acceptor concentrations by a factor of 3.6 − to 6 × 1017≤N a−N d≤ 3 × 1018 cm−3. When the annealed value ofN a − Ndin the InP:Zn layer is 6 × 1017 cm−3 , secondary ion mass spectrometry (SIMS) measurements show abrupt Zn-doping transitions at the heterojunction interfaces. In contrast, when the annealed value ofN a − Ndin the InP:Zn layer is near the saturation value of 3 × 1018 cm−3, SIMS measurements show significant movement of Zn into the nominally undoped InGaAs instrinsic layer. Increasedp-i-n diode capacitance is associated with the Zn movement.

In laboratory tests, larvae of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and the sugarbeet wireworm (SBW), Limonius californicus (Mannerheim), were exposed to the nematodes Steinernema feltiae Filipjev (Mexican strain) (= Neoaplectana carpocapsae) and S. glaseri Steiner in soil. S. feltiae caused significantly higher mortality in SBW larvae than did S. glaseri, but both nematode species were equally effective against CPB larvae. The minimum concentration of S. feltiae for 100% mortality of CPB larvae after 13 days was 157 nematodes/cm(2) of soil, and the LC based on 6-day mortality was 47.5 nematodes/cm(2); in contrast, 100% mortality of SBW larvae was not achieved with even the highest concentration tested, 393 nematodes/cm(2). CPB adults emerging from nematode-contaminated soil were not infected. In field cage tests, S. feltiae applied to the soil surface at the rates of 155 and 310 nematodes/cm(2) soil caused 59% and 71% mortality, respectively, of late-fourth-instar spring-generation CPB, and 28% and 29% mortality, respectively, of SBW. No infection was obtained when larvae of summer generation CPB and SBW were placed in the same cages approximately 6 weeks after nematodes were applied to the soil. Inundative soil applications of S. feltiae, though cost prohibitive at present, were effective in reducing caged CPB and SBW field populations.

Morphological interactions between axons and glia within the lesioned newt optic nerve were studied at time periods prior to the onset of Wallerian degeneration. Optic nerves were transected 0.5 mm from the eye, animals were killed at 5, 10, 20 and 30 min post-lesion, and the intracranial half of the tract was examined with light and electron microscopy. A sequence of structural changes was observed within the time interval 5-30 min post-lesion. Over the first 20 minutes these changes primarily involved the endogenous neuroglia; there was a displacement of glial nuclei from the center to the periphery of the nerve and an increase of 50-100% in glial cytoplasmic and nuclear area. Nuclei of reactive glia were euchromatic and surrounded by a high density of Golgi, vesicles, mitochondria and filaments, the last of which extended throughout the expanded glial processes. Optic axons appear intact at 20 min post-lesion except for some separation between the axolemma and myelin sheath in some of the myelinated fibres. By 30 min post-lesion both myelinated and non-myelinated fibres were found in various stages of lysis. Many of the expanded glial processes contained a population of vesicles aggregated adjacent to the glial plasmalemma. Profiles of infolded glial membranes suggested the opening of such vesicles into the extracellular space around degenerating axons. We conclude that, after optic nerve injury, there are very rapid reactive changes in glia and axons, with the changes in glia preceding the degenerative events in axons.

For organometallic vapor phase epitaxial (OMVPE) grown InP, the change in lattice constant is measured as a function of tellurium (Te) dopant concentration. We observe ~0.15% dilation in the InP lattice constant at a Te concentration of ~1020 cm-3. Our measurements are compared to predictions from Vegard’s Law.

Four closely related nipecotoyl congeners are employed as molecular probes to evaluate the effects of systematic molecular changes upon lethal potency of the compounds. The in vivo toxicities, effected by changes in molecular structure, are compared to their in vitro concentrations inhibiting ADP-induced aggregation and epinephrine-induced primary aggregation of human blood platelets and their toxicities to mouse fibroblasts (L-929 cells) in culture. To assist in the selection of compounds which offer the greatest promise as therapeutic agents for further evaluation and to guide future development of optimal molecular structures, a ratio of acute ip LD50 (mumol/kg) [Tm] to concentration inhibiting 50% ADP-induced platelet aggregation (mumol/liter) [A] is calculated for each compound. These ratios range from 2.41 to 24.92 for the four compounds included in this study.

Limited reaction processing (LRP) of silicon-based materials is reviewed as an alternative growth method to molecular beam epitaxy (MBE). LRP is a chemical vapor deposition technique which uses wafer temperature, rather than gas flow switching, to initiate and terminate growth. Processing takes place within a cold-wall, quartz reaction chamber, and gases are changed between successive lamp-heated growth cycles. In addition to minimizing thermal exposure, the technique allows individual layers in a multi-layer structure to be deposited at their optimum growth temperature. LRP is particularly well suited to the growth and processing of metastable layers such as strained Si1−xGex on silicon. Several properties of LRP-grown Si1−xGex are shown to be similar to those reported for MBE material, including qualitative islanding behavior and quantitative measurement of the onset of misfit dislocation formation. However, a direct comparison of thermal stability reveals larger numbers of misfit dislocations in MBE-grown films upon annealing. The electrical behavior of misfit dislocations in heterojunction diodes, and the growth and analysis of high-quality Si/Si1−xGex/Si heterojunction bipolar transistors are also discussed.

CXCR3 and CCR5 are chemokine receptor that are predominantly expressed on the surface of Th1 polarized T cells. In a variety of human and experimental autoimmune diseases the enhanced expression of CXCR3 and CCR5 binding chemokine ligands is followed by the recruitment of CXCR3- and CCR5-positive T cells, indicating an important role for these chemokine receptors in T cell-mediated tissue damage. In this review, we summarize a number of in vivo studies available on the neutralization of CXCR3 and CCR5 in inflammatory disease, and specifically focus on the potential therapeutic effects of CXCR3 and CCR5 blockade in human autoimmune disease and organ transplantation.

A grazing study was initiated in April 2000 and continued through three calving and weaning cycles (ending July 2003) to investigate the effects of rotational grazing management (twice monthly [2M] vs. twice weekly [2W]) and weaning date (mid-April [EARLY] vs. early June [LATE]) on production of fall-calving cow-calf pairs (495 +/- 9.6 kg initial BW) grazing Neotyphodium coenophialum-infected tall fescue (Festuca arundinacea Schreb.) overseeded with legumes and crabgrass. Secondary objectives of the experiment were to monitor differences in quantity and quality of available forage and to evaluate changes in forage species composition. Pastures were dominated by tall fescue throughout the study, and the proportion of basal cover was greater (P0.05) in 2M than in 2W pastures. The percentage of legumes was very low across all treatment combinations, but the percentage of crabgrass continued to increase (P0.05) linearly and quadratically across years for both summer and fall sampling periods, regardless of rotation or weaning program. In vitro DM disappearance and mineral concentrations varied minimally because of rotation frequency or weaning date. Rotation frequency did not substantially affect (P = 0.11 to 0.97) cow BW, hay offered, milk production, calving interval, calf birth weight, or actual or adjusted weaning weights; however, 2M cows had 0.3 units higher (P0.05) BCS at the time of breeding than 2W cows. Calves weaned late had greater (P0.05) actual weaning weight and weighed more (P0.05) on the LATE weaning date than on the EARLY weaning date, but 205-d adjusted weaning weights did not differ (P = 0.74) across weaning dates. Therefore, rotation frequency and/or weaning date had little effect on forage species composition or forage quality. In addition, the rapid rotation program offered little advantage with respect to animal performance, and weaning fall-born calves grazing endophyte-infected tall fescue pastures at approximately 189 d of age seemed to be detrimental to calf performance compared with delaying weaning until 243 d of age.

Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often viewed as an undesirable weed, largely because it encroaches upon field and forage crops, gardens, and lawns. However, visual observations of livestock grazing mixed-species pastures suggest that cattle seem to prefer crabgrass to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11, and August 22, 2001, and then to determine ruminal in situ disappearance kinetics of DM and NDF for these crabgrass forages. A secondary objective was to compare these kinetic estimates with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and orchardgrass (Dactylis glomerata L.) control hays. All forages were evaluated in situ using five (383 +/- 22.7 kg) ruminally cannulated crossbred (Gelbvieh x Angus x Brangus) steers. Whole-plant crabgrass exhibited more rapid (Por = 0.002) ruminal disappearance rates of DM (overall range = 0.069 to 0.084 h(-1)) than did bermudagrass (0.054 h(-1)) and orchardgrass (0.060 h(-1)) hays, but disappearance rates were slower (P0.001) for crabgrass than for alfalfa hay (0.143 h(-1)). Effective ruminal disappearance of DM was greater (P0.001) for crabgrass (overall range = 69.3 to 75.4%) than for all the control hays. Similarly, disappearance rates of NDF for crabgrass (overall range = 0.069 to 0.086 h(-1)) were more rapid (P0.001) than observed for bermudagrass and orchardgrass hays; however, NDF in alfalfa disappeared at a faster (P0.001) rate (0.107 h(-1)) than crabgrass. These results indicate that crabgrass offers greater effective ruminal degradability of DM and NDF than orchardgrass or alfalfa of moderate quality. More importantly, it potentially offers faster and more extensive ruminal disappearance than perennial warm-season grasses typically found throughout the southeastern United States, and it should likely support improved performance by ruminant livestock in this region.

Silicon thermal oxidation was used to characterize the interaction of Si interstitials with a Si1−xGex layer and with B in Si1−xGex. Diffusion of B in a Si marker layer, positioned under a Si1−xGex layer, was monitored as excess Si interstitials were injected into the bulk by the oxidation of the Si capping layer (T=850 °C, t=18 min). The Si1−xGex layer did not affect the oxidation‐enhanced diffusion of B in the Si marker layer. Hence, Si1−xGex (x

Boron diffusion in in situ doped Si1−xGex and Si, subjected to inert‐ambient furnace annealing at 800 °C, was investigated. For Si1−xGex, the effect of biaxial compressive and tensile strain on boron diffusion was studied using Si1−xGex layers with a constant Ge content (x≊0.10 and x≊0.20) grown epitaxially on various relaxed Si1−yGey (0≤y≤0.20) substrates. Boron diffusion is primarily a function of Ge content, x in the Si1−xGex layers, and does not show a strong dependence on macroscopic biaxial strain. For Si, the effect of biaxial tension was investigated using relaxed Si1−yGey layers as substrate templates for epitaxial Si layers. As in Si1−xGex, boron diffusion in Si does not depend strongly on biaxial strain.

The work reported here was originally motivated by a discussion of Monte Carlo computer codes for electron transport in water given in Report No. 130 by the National Council on Radiation Protection and Measurements (NCRP). It was pointed out (correctly) that a published depth-dose distribution calculated by the Oak Ridge electron transport code, OREC, for 800 keV electrons normally incident on a water slab was apparently in error, possibly due to inadequate treatment of elastic scattering. In this paper we describe the replacement of the original OREC elastic cross sections by current ones from the National Institute of Standards and Technology (NIST). This investigation led also to the critical examination and revision of some other parts of the program, as described here. The revised code, which we have renamed NOREC, represents the first substantial review and modification of the Oak Ridge code in a number of years. We also present some comparisons of results calculated with the old and new versions and discuss their implications with respect to earlier studies. We have also written a version of NOREC in C++ language, which is available to other investigators. This paper provides a record of a response to the NCRP published statement and documentation for the revised code, NOREC.

Small-geometry, high-performance Si-Si/sub 1-x/Ge/sub x/ heterojunction bipolar transistors have been fabricated using chemical vapor deposition to form the epitaxial device layers and direct-write, electron-beam lithography. The measured value of f/sub T/ is approximately 29 GHz. Base-collector capacitance is one of the dominant limiting parasitic parameters in the mesa structure used to demonstrate high-speed performance. Advanced epitaxial techniques, such as selective deposition of Si/sub 1-x/Ge/sub x/, should reduce this parasitic element significantly, markedly increasing device speed. Selective deposition of Si/sub 1-x/Ge/sub x/ has been demonstrated. >

The DC performance of Si/Si/sub 1-x/Ge heterojunction bipolar transistors (HBTs) fabricated from epitaxial layers grown by limited reaction processing is presented. The highest gain ( approximately=400) device has a 20-nm, 31%-Ge base heavily doped with boron to a level of 7*10/sup 18/ cm/sup -3/. Measurements of the collector current as a function of temperature yield values of the valence band discontinuity, Delta E/sub v/, for four different Ge compositions. The dependence of Delta E/sub v/ on Si/sub 1-x/Ge/sub x/ layer thickness was also measured and found to decrease as strain relaxation occurred. >

The initial results from an investigation into the feasibility of using plasma source ion implantation (PSII) to produce separation by implantation of oxygen structures in silicon are reported. Oxygen ions are implanted into p‐type (111) oriented silicon wafers using a −30 kV acceleration potential and an oxygen plasma at a pressure of 0.2 mTorr. The effects of ion dose and high‐voltage pulse width were examined. Some of the implanted wafers were annealed. Both the as‐implanted and annealed wafers were examined using secondary‐ion‐mass spectroscopy and Auger electron spectroscopy. The initial results show that oxygen can be implanted by PSII and suggest that a buried layer of silicon dioxide has been formed in the implanted wafers.

The authors discuss the major reasons and solutions for selectivity loss during selective tungsten deposition. By applying these solutions to the selective process the nucleation count on the dielectric can be reduced to less than 1 nuclei/cm/sup 2/. In addition, a novel process has been developed in most photoresist is used as a sacrificial layer and an antinucleation layer is used to reduce the tungsten nucleation count on the surface of the dielectric to 0 nuclei/cm/sup 2/. The chemistry involved in producing a low-resistance contact on 0.7- mu m-diameter contacts is also discussed. Electrical test results showing contact resistance data on 0.7- mu m-diameter via chains with corresponding bridging data are presented. >

The properties of the polysilicon/silicon interface which contribute to variations in DC performance of bipolar transistors are investigated. Measurements of interfacial oxide thickness and epitaxial realignment of the polysilicon are correlated with gain, emitter resistance, and poly sheet resistance from complete devices, two-mask bipolar structures, and unpatterned implanted poly subjected to base-emitter drive cycles. The data obtained suggest that significant benefits may be realized in the fabrication of diffused polysilicon bipolar transistors if rapid thermal processing is used for the emitter drive. Higher gain and potentially lower emitter resistance may be obtained if epitaxial realignment is initiated by minimizing the amount of interfacial oxide introduced prior to deposition. >

Ruminal in situ disappearance kinetics of forages are commonly evaluated in confined animals, but there have been relatively few attempts to evaluate disappearance kinetics of forage dry matter (DM) in grazing animals. Our objectives were 1) to evaluate the effects of harvest technique and sampling date on the in situ DM disappearance kinetics and nutritive value of wheat ( Triticum aestivum L.) forage, and 2) to compare the in situ disappearance kinetics of DM for these forages when the experimental steers were housed in confinement with those obtained from steers grazing wheat pasture. Wheat forage was harvested on three dates (March 6, March 27, and April 11, 2000). Sampling techniques evaluated on each date included three clipping techniques (whole plant, random pluck, and top half) and two evaluations of masticates (oven dried at 50°C or lyophilized). There was an interaction of harvest technique and sampling date main effects for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, cellulose, lignin, and whole-plant ash. Disappearance kinetics of DM for these 15 forages were then evaluated by the in situ technique using five 393-±54-kg crossbred steers consuming an alfalfa-based ( Medicago sativa L.) diet in confinement, and subsequently, in five 448±49-kg crossbred steers grazing wheat pasture during March 2001. For fractions A, B, and C, potential extent, rate of disappearance (K d ), and effective ruminal degradability, linear regressions of values obtained for steers grazing wheat pasture on those obtained from confined cattle had significant slopes and exhibited high r 2 statistics (>0.821). For fractions A and B, and K d , the slope of these regression lines did not differ from unity, and the intercept did not differ from zero. For fraction C, potential extent of disappearance, and effective ruminal degradability, slopes were all equal to 1.19 and differed from unity. For effective degradability, deviation of the slope from unity can be explained, in part, on the basis of the passage rates used to calculate these values (0.035 and 0.062/h for confined and grazing steers, respectively). From a practical standpoint, the in situ disappearance kinetics of DM for these wheat forages did not appear to be altered substantially by evaluating them in grazing steers.

Our objectives were to determine whether repeated administration of prostaglandin F2alpha (PGF2alpha) to simulate the endogenous mode of secretion would be more effective than a single injection in inducing luteolysis and enable use of smaller doses less likely to cause adverse side effects. The main study comprised 43 dioestrous mares, who were given im. either a single 10 mg dose of natural PGF2alpha (n = 22) or 2 doses of 0.5 mg PGF2, 24 h apart (n = 21). The intensity of side effects was assessed in 8 dioestrous mares given 5, 1.5, 0.5 or 0 mg PGF2alpha in consecutive cycles. Two doses of 0.5 mg PGF2alpha 24 h apart caused lysis of the corpus luteum in all mares, whether this was determined from a fall in plasma progesterone concentrations or reproductive tract/behavioural changes; and when 10 mg PGF2, was given, the corpus luteum was lysed in 17 of 22 mares i.e. a lower proportion (P = 0.0485). A single dose of 0.5 mg PGF2a was no more effective than saline in inducing luteolysis.The intensity of side effects of PGF2alpha increased with dose. Although the 0.5 mg dose was no more likely than saline to cause sweating or muscle spasms, it raised plasma cortisol concentrations and prevented the decline in heart rate seen after saline. We conclude that a 2 dose regimen of administration increases the luteolytic efficacy of PGF2alpha and thereby provides a way to minimise adverse side effects.

Limited information is available that describes the disappearance kinetics of bermudagrass (Cynodon dactylon L. Pers.) during fall and early winter. Five ruminally cannulated, crossbred steers (387 +/- 18.3 kg) were used to determine the effects of calendar date and previous summer management on the in situ degradation kinetics of DM and NDF for forage clipped from stockpiled 'Greenfield' bermudagrass pastures. Forage was stockpiled at two sites following summer hay or pasture management, and samples were taken outside (GRAZED) and under caged exclosures (UNGRAZED) at 4-wk intervals beginning October 17, 1997, and ending January 9, 1998. No effort was made to remove or avoid contaminate species. Concentrations of NDF increased (P0.001) to a maximum for UNGRAZED forages at the hay site between October 17 and December 12, but sampling date had no effect (P = 0.627) on concentrations of NDF at the pasture site. Concentrations of ADF and lignin increased (Por = 0.023) during at least one sampling interval in UNGRAZED forages at both sites. At the hay site, degradation rates of DM decreased (P0.001) by 0.013/h for UNGRAZED forage between October 17 and January 9, whereas the effective ruminal degradability of DM decreased (P0.001) by 33.5% during the same time period. Fractional degradation rates of NDF for UNGRAZED forages at the hay site decreased (P0.001) by 0.014/h between October 17 and November 14 but did not change (Por = 0.077) throughout the remainder of the study. The effective ruminal degradability of NDF decreased (P0.001) by 33.8% between the first and last sampling date. At the pasture site, sampling date did not affect (P = 0.458) rates of DM degradation, but the effective degradability of DM for UNGRAZED forages decreased (P = 0.001) by 19.0% from October 17 to December 12. Rates of NDF degradation for UNGRAZED forages did not differ (Por = 0.113) on the first three sampling dates, but the rate on January 9 was slower than that observed on October 17 (P = 0.025) and November 14 (P = 0.044). The effective degradability of NDF decreased (P0.001) by 19.2% between October 17 and December 12. These data indicate that stockpiled bermudagrass should be used during a limited window during the late fall; after this time, the nutritive value becomes very poor.

We have investigated boron diffusion in Si and strained Si1−xGex, in situ doped, epitaxial layers. During inert ambient annealing at 860 °C, boron diffusion is observed to be slower in Si0.83Ge0.17 than in Si for boron concentration levels between 5×1016 and 2.5×1019 cm−3. Computer simulations of the measured boron profiles for annealed samples indicate that the effective boron diffusivity Deff in Si0.83Ge0.17 is approximately an order of magnitude lower than that in Si. This disparity is found to increase with increasing boron concentration.

A primary focus of dental education is to teach students the knowledge, skills, and values essential for practicing dentistry. However, the preparation of dentists to manage a business is frequently cited as inadequate. A survey was prepared to assess teachers' opinions of business instructional topics: challenges; desired training; employee benefits; learning resources; importance of business topics; and appropriateness of time allocations. The purpose of this project is to compare opinions of teachers of dental practice management with key management aspects reported for service businesses by the Small Business Development Center (SBDC). Practice management teachers from forty-eight (89 percent) schools responded to the survey. They indicated that several challenges confronting dentists are similar to other service businesses. Dentists, however, rank customer relations appreciably higher. In order of importance of teaching topics, the practice management teachers rank ethics and personnel management as a high priority and planning as a low priority. Awareness of the similarities and differences in the perceptions of practice management teachers and businesspeople may result in instructional improvements.

The kinetics of selective deposition of epitaxial Si1−xGex layers in an atmospheric‐pressure reactor have been examined. Adding HCl to the SiH2Cl2/GeH4/H2 system decreases the Si component of the deposition rate more than the Ge component, increasing the Ge fraction in the deposited layer. HCl addition also decreases boron incorporation. When deposited selectively on oxide‐patterned wafers, lateral transport of the depositing materials causes the deposition rate and the Ge fraction to be higher in small patterns than in large patterns and also to be higher near the edges of patterns than at their centers.

Admittance spectroscopy has been used to measure conduction‐ and valence‐band discontinuities in Si/Si1−xGex heterojunctions (0

Wheat ( Triticum aestivum L.), oat ( Avena sativa L.), and rye ( Secale cereale L.) were overseeded into a dormant bermudagrass ( Cynodon dactylon (L.) Pers.) sod and harvested at 3-wk intervals throughout March, April, May, and early June. Plant growth stage was documented for each forage on each harvest date, and harvested forages were evaluated for forage quality characteristics. Degradation kinetics of DM and NDF for these forages were evaluated by the in situ method. Fractional degradation rates for DM and NDF in all three species were relatively rapid for vegetative forage (≥0.086h –1 ) but declined rapidly by the heading stage of development and stabilized thereafter. Forage quality declined and forages were more resistant to ruminal degradation as plants entered the reproductive stages of growth. Based on these findings, growth stage is an effective predictor of most characteristics of in situ DM and NDF disappearance. The relationships between these degradation parameters and growth stage were typically explained with quadratic or cubic models. Clearly, forage quality characteristics of overseeded rye deteriorated more rapidly with phenological development and growth stage than quality characteristics of overseeded wheat and oat grown in the same environment. For rye, this problem is further complicated by its accelerated phenological development. These factors combine to permit a very narrow harvest window in early spring, relative to the other cereal grains evaluated. Acceptable forage quality may persist for an extended period in wheat and oat; this suggests that producers wishing to utilize these forages may lengthen the harvest window by planting more than one species, either as a mixture or preferably in independent stands.

The thermal stability of Si1−xGex strained layers containing 2×1020 oxygen atoms/cm3 is compared with that of similar layers (same Ge fraction and film thickness) containing more than two orders of magnitude less oxygen. For the layers with high oxygen levels, no misfit dislocations were found in films as thick as two times the theoretical equilibrium critical thickness, after annealing at 850 °C for 4 min. In contrast, dislocations were found in the layers with low oxygen levels at thicknesses very near the equilibrium critical thickness after the same anneal. X‐ray measurements of lattice constants in high and low oxygen films of similar Ge content indicate that oxygen does not substantially change the amount of strain in the layers. Oxygen appears to impede the kinetics of dislocation formation.

A p+‐i‐n diode structure is presented which is suitable for determining the recombination lifetime in thin Si1−xGex layers grown on Si. Electrical measurements and computer simulations are used to extract carrier lifetimes in Si1−xGex layers with various oxygen concentrations. The minority‐carrier lifetime increases dramatically as the oxygen concentration in the Si1−xGex decreases from 3×1020 to less than 3×1017 cm−3. Lifetimes extracted from the p+‐i‐n diodes are consistent with those obtained from measurements on heterojunction bipolar transistors with high oxygen concentrations in the Si1−xGex base.

Aspirated exudate from 50 patients with oral abscesses were cultured and bacterial growth was assessed qualitatively and semi-quantitatively. Bacteria were recovered from all specimens. The mean number of species isolated per specimen was 3.6 Both facultative and obligate anaerobes were isolated from 39 (78%) specimens. The most commonly isolated facultative anaerobic species was Streptococcus virdans group, while pigmented gram negative bacilli were the most commonly isolated obligate anaerobes. Beta-hemolytic Streptococci of the "milleri" groups were recovered from 11 (22%) of the abscesses. Eight of those isolates were determined to carry Lancefield group F antigen, 2 group C, and 1 isolate was not groupable for any Lancefield antigen. These abscesses may be sequelae of oral infectious disease or trauma. Patients with oral abscesses infected with beta hemolytic Streptococci are apt to be male, and less than 35 years old. They are also likely to have a more rapid onset of infection and to require hospitalization for intensive treatment of a life threatening condition.

An experimental bipolar transistor structure with self-aligned base-emitter contacts formed using one polysilicon layer is presented with geometries and frequency performance comparable to those of double-polysilicon structures. This structure, called STRIPE (self-aligned trench-isolated polysilicon electrodes), provides a 0.2- mu m emitter-base polysilicon contact separation. A 0.4- mu m emitter width is achieved with conventional 0.8- mu m optical lithography. Scaling of the emitter width of 0.3 mu m has been performed with minimal degradation of device performance, and scaling of the emitter width pattern to 0.2 mu m has been demonstrated. These dimensions are the smallest achieved in single-polysilicon structures with polysilicon base contacts and are comparable to those achieved in double-polysilicon structures. The STRIPE structure has been used to fabricate transistors with f/sub t/ as high as 33.8 GHz. >

The recognition of a pathologic entity is only the first step in the chain of events which must be performed for accurate diagnoses and appropriate patient management. Other steps include selection of the type of biopsy to be performed; proper biopsy technique, instrumentation and specimen handling; appropriate fixation; detailed documentation; and postoperative patient instructions. If the clinician performs each step carefully and correctly, the patient is ensured of receiving an accurate diagnosis in the shortest possible period of time.

In a previous study, an antigen consisting of proteins secreted by retinal pigment epithelial (RPE) cells was injected into a sheep and the specificity of the resulting antiserum was shown by Western blotting and its effects on retinal development were determined in vitro and in vivo. In the present study, the distribution of these secreted proteins was determined by light microscopy immunocytochemistry in cultured neonatal rat RPE cells and retinas of normal and Royal College of Surgeons (RCS) dystrophic rats and cerebrum of normal adult rats. Immunolabelling for these RPE-secreted proteins was detected in cytoplasmic vesicles surrounding nuclei and within processes of cultured normal and transformed rat RPE. In retinas of late postnatal and adult rats, dense immunostaining was found in the cytoplasm of RPE cells and ganglion cell bodies. In addition to RPE and ganglion cells, scattered photoreceptors within the thin outer nuclear layer and small structures within the debris zone were also densely immunoreactive in retinas of 2-mo-old RCS dystrophic rats. The numbers of immunostained ganglion cells appeared to decrease in retinas of older RCS rats, although the immunoreactivity within the RPE appeared to increase in density. No other neuron within the retina, i.e. bipolar, amacrine or horizontal, was immunoreactive for RPE-secreted proteins. In the cerebral cortex of adult rats, immunoreactivity for RPE-secreted proteins was primarily detected within large perikarya of pyramidal neurons and smaller granule neurons. In conclusion, we report an immunocytochemical analysis of an antiserum raised against secreted proteins of rat RPE. This antiserum recognised proteins within secretory-like vesicles of cultured neonatal normal and transformed rat RPE and showed a specificity for RPE and ganglion cells in normal rat retinas, that appeared to be developmentally regulated, and neuron perikarya in adult rat cerebrum.

An odontoma refers to any tumor of odontogenic origin. Three distinct types of odontomas have been distinguished in the dental literature: complex, compound, and ameloblastic fibro-odontoma. Odontomas are usually associated with overly retained primary and unerupted permanent teeth. The exact etiology of odontomas is unknown, but local trauma, infection, inheritance, and genetic mutation have been postulated as possible causes of odontomas. Studies have found that males are more likely than females to have odontomas, with most frequent occurrence in the second decade of life. One hundred four biopsy reports with a diagnosis of odontoma were analyzed for age, race, gender, location, pre-operative diagnosis, and postoperative laboratory findings. Most odontomas occurred in the 11-20 age group, with Caucasians predominating. The majority were located in the maxilla, and 85 percent were correctly diagnosed clinically by the attending dentist prior to confirmation by histologic pathology reports of the biopsy specimens. The vast majority were compound odontomas (64.4%) with complex odontomas comprising 31.0% of the total lesions. No ameloblastic fibro-odontomas were diagnosed.

Chairside dental ethics necessitates special consideration by the faculty member-dentist, the dental student, and the patient. The patient must always be aware of treatment options, in addition to learning the health status of the oral hard and soft tissues, costs, and time to be involved to accomplish proposed treatment. What may seem like a burden to an individual practitioner is actually only the necessities incurred by any self governing profession. Fifty-two consecutive dental patients had their cases reviewed for the ethical behavior of the dentist-practitioner, student, and patient. Categories reviewed were informed consent (100%), agreement, compromise, economic issues, conflict, and institutional issues. The results were: 1. Agreement: 17 cases, 2. Compromise: 21 cases, 3. Economic Issues: 4 cases, 4. Conflict: 6 cases, and 5. Institutional Issues: 4 cases. Fourteen percent of all patients were minors. Ninety percent of the patients were treated. Of those 10% not treated, five percent were for medical reasons, and five percent of the patients refused treatment. These results were placed in the Ozar Model 9 and were categorized as follows: 1. Appropriate pain free oral function: 22 cases, 2. Patient Autonomy: 14 cases, 3. Life and health: 9 cases, 4. Preferred practice values: 6 cases, and 5. Other external considerations: 1 case. This template demonstrated appropriate ethical behavior on the part of dentists, students, and patients, especially with a 90% treatment group, and only 5% refusing treatment. The 52 consecutive patients were characteristic of the University of Tennessee's overall patient pool. No identifiable differences were found between patients regardless of gender, age, or race.

Ramsay Hunt's syndrome is an infectious cranial polyneuropathy caused by varicella zoster, the herpetic virus that also causes chickenpox and shingles. Its symptoms include facial paralysis, ear pain, and an auricular rash. Oral lesions are also present in most cases. This syndrome can affect any cranial nerve and usually affects multiple nerves, causing central, cervical, and peripheral effects. This article reports the case of a 35-year-old white female who was treated by the oral surgery service of a large urban hospital, after first reporting to the emergency clinic. Her reported symptoms of unilateral left-side facial paralysis, auricular pain, and trigeminal hyperesthesia were confirmed by clinical examination. An initial short low-dose steroid regimen was unsuccessful. A second daily dosage of 50 mg of prednisone was successful in 21 days. No permanent sequelae were evident or reported after treatment.

During a routine dental appointment at a dental school clinic, a fifteen-year-old black male patient was diagnosed with severe erosion of the dentition together with several carious lesions and a crowded dentition. During treatment of the carious lesions, severe erosion (perimylolysis) of the maxillary and mandibular teeth were observed, which at first alerted the attending clinician to a preliminary diagnosis of anorexia and/or bulimia. Because of the age, gender and social and medical history of the patient, these preliminary diagnoses were discounted, with a hypothesis of gastrointestinal disorder presented to the patient and his parents after consultation with oral medicine and oral pathology faculty. Saliva pH analysis, along with further research concluded that gastrointestinal reflux disease (GERD), surreptitious rumination, or a combination of both were possible diagnoses. Referral to a gastroenterologist for further examination was recommended, while a night-guard was fabricated for the patient to wear at night with fluoride gel. Root canal therapy together with prosthodontic care are often treatment options for patients suffering from gastrointestinal problems. This paper demonstrates how important routine dental examinations are, especially since dentists can often recognize systemic disorders whose symptoms first appear in the oral cavity.

Background Historically ambulance care quality and performance has been measured by response times rather than clinical need or effectiveness. This limits the evidence about the effectiveness of the care the ambulance service provides. The Pre-hospital Outcomes for Evidence Based Evaluation (PhOEBE) project is a 5 year research programme which aims to develop new ways of measuring the performance, quality and impact of ambulance service care that better reflect the care provided. Methods We held a 1 day consensus event with a multi-stakeholder group to identify and prioritise which features of ambulance service care are important and worth further development as measures of performance and quality. The day comprised a series of small group discussions to share opinions about measures identified from literature reviews and the opportunity for participants to add their ideas, together with a live vote to help identify and rank measures for further development. Time measures were considered in a separate online questionnaire. The results from the online questionnaire and Consensus Event were fed into a Delphi study. Results 43 participants attended the consensus event, representing a range of participant groups including patient and public, ambulance services, commissioners and policy groups. The top 5 outcome measures prioritised by the participants were: accuracy of dispatch decisions; completeness and accuracy of patient records; accuracy of call taker identification of different conditions or needs (e.g. heart attack, stroke, suitable for nurse advice); pain measurement and symptom relief; and patient experience. From the online survey of time measures the top 5 measures were time of call to time of arrival at scene; time symptoms start (e.g. chest pain) to time of treatment with balloon for heart attack; time taken to answer the emergency call; total time spent on scene; and incident or start of symptoms to calling the ambulance service. Conclusion Using consensus methods we have identified a set of outcome measures that can potentially be used to measure the performance and quality of ambulance service care. Some of these measures fit with existing government targets, such as response times and time taken to answer the emergency call. However, most measures are new ways of measuring ambulance service care and the importance of these measures and methods of measurement will be assessed as part of an on-going Delphi study.

Injuries associated with the category of dental surgical instruments known as "sharps" (i.e., syringe needles, glass, scalpel blades, dental burs, and hand instruments) are a serious concern for dental professionals because of the possible transmission of communicable diseases such as tuberculosis, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV). Hepatitis B virus has been recognized as an occupational hazard for dentists and other health-care professionals for several decades. The transmission of HIV from dentist to patient in the dental office has been known to occur in only one practice, and the vector of transmission remains unknown. No dentist has ever been reported to have contracted HIV from a patient. Adherence to infection-control procedures, especially barrier protection, has been linked closely to keeping the incidence of these infections low. This article discusses the results of an anonymous survey about "sharps" injuries and communicable diseases that was given to dentists/faculty, students, and support staff at an urban dental-school clinic.

This study demonstrates the effects of conditioned media from transformed neonatal rat retinal pigment epithelial cells (tnrRPE-CM) in a culture system consisting of neonatal rat retinal explants. For this study, retinal explants from postnatal day 2 (PN2) normal rats were cultured for over 3 weeks on a poly-D-L-ornithine-coated surface in RPE-CM only, 10% serum, or a serum-free defined media, and then examined by phase-contrast and scanning electron microscopy and immunocytochemistry. After 2 days in vitro, long ganglion cell-like neurites projected from retinal explants grown in tnrRPE-CM. These neurites increased in number and length with prolonged time in culture. In addition, by 5 days, round cells were observed adjacent to neonatal explants grown in tnrRPE-CM. By day 10, these round cells had increased in number and were seen along the neurites, in massive clusters immediately adjacent to these explants and dispersed throughout the culture-plate surface. Media conditioned by primary cultures of normal neonatal rat RPE cells caused a similar, but less robust, cellular response in retinal explants when compared to tnrRPE-CM. At 10 days, retinal explants grown in 10% serum showed only a few short processes, but no round cells, while those explants grown in defined media appeared to be degenerating. The round migrating cells are classified as retinal progenitor cells since they immunostained for opsin and interphotoreceptor retinoid-binding protein (IRBP), two photoreceptor cell markers, and a few for cellular retinaldehyde binding protein (CRALBP), a Muller cell marker. Neurite outgrowth and retinal progenitor cell production from explants were eliminated when the tnrRPE-CM was subjected to trypsin or heat treatment, indicating that the factor(s) responsible for promoting these cellular events was most likely proteinaceous. Growth factors, including basic fibroblast growth factor, were unable to generate long neurite outgrowth or progenitor cell production as observed in RPE-CM-supplemented explant cultures. We report that CM from cultures of primary and transformed neonatal rat RPE cells promoted ganglion cell-like neurites and the production of migrating retinal progenitor cells that primarily expressed photoreceptor-specific markers, from neonatal rat retinal explants. This evidence further confirms the important role of RPE in retinal development. The production of large numbers of progenitor cells by an RPE-secreted factor(s) may have important implications for possible therapeutic approaches to help correct retinal disease states by replacing lost cells through transplantation technology.

Rat tracheal epithelial cells exposed directly on planar 210Po sources exhibited exponential cell killing; however, no significant increase in induction of preneoplastic transformation was observed over a range of alpha-particle fluences (0.017-0.050 micron-2). In contrast, up to 10-fold increases in frequencies of preneoplastic transformants, above control levels, were observed after exposure of rat tracheal epithelial cells to similar alpha-particle fluences on 238Pu and 241Am sources. Two alternative hypotheses are evaluated as an explanation for this apparent difference in the biological effect of alpha particles emitted from different sources: (a) possible interactions between effects produced by alpha particles and by low-energy photons, which occur with 238Pu and 241Am but not with 210Po; and (b) the influence of spatial relationships between exposed cells and the surface of the planar source. The data suggest that cell-to-source spatial relationships affect both survival and transformation markedly.

The role of sphingomyelin-derived second messengers in progesterone-induced reinitiation of the meiotic cell cycle of Xenopus laevis oocytes was investigated. A brief treatment of defolliculated oocytes with sphingomyelinase (Staphylococcus aureus) was sufficient to induce maturation as measured by H1 kinase activity and germinal vesicle breakdown (GVBD). Pretreatment with cycloheximide inhibited sphingomyelinase-induced GVBD demonstrating a requirement for protein synthesis. Microinjection of ceramide or sphingosine, potential products of sphingomyelin hydrolysis, were capable of inducing GVBD in the absence of hormone. Metabolic labeling studies suggested the conversion of sphingosine to ceramide was necessary for sphingosine-induced GVBD. Additionally, fumonisin b1, an inhibitor of sphingosine N-acyltransferase, blocked sphingosine-induced GVBD demonstrating that ceramide is the more proximal biologically active metabolite. Treatment of oocytes with progesterone, the physiological inducer of oocyte maturation, resulted in a time- and concentration-dependent increase in the mass of ceramide and decrease in the mass of sphingomyelin through activation of a Mg(2+)-dependent neutral sphingomyelinase. These observations suggest that the generation of ceramide from sphingomyelin is part of the signal transduction pathway activated in response to progesterone and that the increase in ceramide is likely to be functionally important in resumption of the meiotic cell cycle.

Boron diffusion in in-situ doped Si and strained Si1−xGex (x < 0.20) epitaxial layers, subjected to inert-ambient furnace annealing, was investigated as a function of temperature (T = 750 °C - 850 °C). Boron diffusivity parameters were extracted from SUPREM IV, a process simulation program. We observed slower B diffusion in strained Si1−xGex relative to that in Si for B concentration levels ranging from 2×1017 to 3×1019 cm−3. Using relaxed graded Si1−xGex as “substrates”, we also characterized B diffusion in relaxed Si1−xGex (x < 0.60) at T = 800 °C. We propose a reaction of mobile B atoms pairing with Ge atoms to model the slower B diffusion in both fully strained and relaxed Si1−xGex.

The chemotoxicity and radiotoxicity of trans-dichlorodiammineplatinum (II) labeled with (195m)Pt (trans-(195m)Pt) are investigated to ascertain the potential of radioplatinum coordination complexes as antineoplastic agents. Platinum-195m, with a half-life of about 4 days, is a prolific emitter of low-energy Auger electrons because of the high probability of internal conversion in its isomeric transitions. The kinetics of cellular uptake and retention after incubation and the radiotoxicity of this Auger electron emitter in the form of trans-(195m)Pt is investigated using cells of the Chinese hamster V79 cell line. The cellular uptake of (195m)Pt reaches a plateau in about 3 to 5 h of incubation and varies nonlinearly with the extracellular concentration of radioactivity. The radioactivity is eliminated from the cells after incubation with an effective half-life of 24 h. Cell survival data, when corrected for the chemical toxicity of nonradiolabeled trans-platinum, give a cell survival curve typical for radiations with high linear energy transfer. At 37% survival, the mean lethal cellular uptake is about 1.0 mBq/cell. Dosimetric considerations, based on subcellular distribution of the radionuclide, yield a value of 4.8 for the relative biological effectiveness when compared with 250 kVp X rays. Theoretical Monte Carlo track-structure calculations indicate that the density of radical species produced in liquid water in the immediate vicinity of a (195m)Pt decay site is substantially greater than the density of species along the track of a 5.3 MeV α particle. This explains qualitatively the efficacy of (195m)Pt in causing high-LET radiation type biological effects. The extreme radiotoxicity of intranuclearly localized (195m)Pt, in conjunction with the proclivity of platinum chemotherapy agents to bind to DNA in the cell nucleus, suggests that the combination of chemical effects and the effects of Auger electrons that can be obtained with radio-platinum coordination complexes may have potential in the treatment of cancer.

Brain abscess is a rare, extremely aggressive, life-threatening infection. A mortality rate of between 36% and 90% has been reported as recently as 1990. It is resistant to antibiotics and is one of the few bacterial infections whose morbidity and mortality statistics remain unaffected by the development of antimicrobial medications. Successful treatment appears to be dependent on early diagnosis, surgical intervention, and direct antibiotic irrigation of the surgical wound site, as well as intravenous administration of high doses of antibiotics throughout the crisis. It has been suggested that there is a relationship between dental infection or treatment and brain abscess. Dental infection and treatment have been found culpable in numerous cases reported in the literature. However, careful review of the articles reveals that dental infection or treatment has often been named as a causative factor (1) solely because an infection or treatment occurred within several months of brain abscess; (2) when nondental bacteria were cultured from the brain abscess; and (3) without culturing both the dental infection and the brain abscess to ascertain flora match.

Healthy retinal pigment epithelial (RPE) cell transplants in retinas of postnatal day 27 Royal College of Surgeons (RCS) rat are capable of preventing photoreceptor cell degeneration, inhibiting the degeneration of the retinal vascular bed and the subsequent neovascularization of the RPE that occurs in retinas injected with saline. In the present study, the authors have tested the hypothesis that RPE transplants might also prevent vascularization of the RPE layer in RCS retinas when photoreceptor cells either had just degenerated or, at 3 months, disappeared.Retinas of 3- and 6 month-old RCS rats were injected with either healthy neonatal RPE cells or vehicle and were examined at 6 and 8 months, respectively. These retinas were studied using horseradish peroxidase visualization of the vasculature in retinal wholemount preparations and by light microscopy.The number of neovascular profiles in wholemount preparations of RCS retinas that had received healthy RPE transplants at 3 months and were analyzed at 6 months were significantly decreased when compared to sham-injected retinas of age-matched RCS rats, 2.09 +/- 0.94 and 15.28 +/- 1.34 profiles per mm2, respectively (P0.001). In addition, when comparing retinas transplanted or sham injected at 6 months and examined at 8 months, significantly fewer neovascular profiles were found in the transplant group, 9.32 +/- 1.02 and 15.42 +/- 0.84 profiles per mm2, respectively (P0.002).These data provide still further evidence for the role of healthy RPE in maintaining the homeostasis of the normal retinal vasculature in the retina of the RCS rat. The relationships between the RPE and the retinal vasculature are important when considering that alterations in the vascularization of the retina play a major role in some of the most sight-debilitating diseases, such as the wet form of age-related macular degeneration and proliferative diabetic retinopathy.

Optimum high-frequency performance of Si/Si1-xGex heterojunction bipolar transistors can be obtained only with precise control of doping profiles within the heterostructure. With low-temperature chemical vapor deposition and advanced SIMS depth profiling techniques, we demonstrate the capability to place and measure hyperabrupt boron junctions relative to the Si/Si1-xGex heterointerface with an accuracy of 20 Angstroms. Capacitance-voltage measurements as a function of junction displacement from the heterojunction are also presented. Measurements of boron diffusivity in Si1-xGex strained layers are combined with data on boron segregation in the Si/Si1-xGex system to accurately model dopant motion across the heterointerface.