Feeding dicyandiamide (DCD) to cattle: An effective method to reduce N2O emissions from urine patches in a heavy-textured soil under temperate climatic conditions.

Nitrate (NO3-) leaching and nitrous oxide (N2O) emission from urine patches in grazed pastures are key sources of water and air pollution, respectively. Broadcast spraying of the nitrification inhibitor dicyandiamide (DCD) has been shown to reduce these losses, but it is expensive. As an alternative, it had been demonstrated that feeding DCD to cattle (after manual mixing with supplementary feeds) was a practical, effective and cheaper method to deliver high DCD rates within urine patches. This two-year study carried out on simulated urine patches in three application seasons (spring, summer, autumn) explored the efficacy of DCD feeding to cattle to reduce N losses from grazed pasture soil in a heavy-textured soil under temperate climatic conditions. In each application season, DCD fed to cows, then excreted with urine and applied at a rate of 30kgDCDha-1 (treatment U+DCD30-f) was as effective as powdered DCD mixed with normal urine and applied at the same rate (treatment U+DCD30) at reducing cumulative N2O-N emissions and the N2O-N emission factor (EF3, expressed as % of N applied). Increasing DCD loading within urine patches from 10 to 30kgDCDha-1 improved efficacy by significantly reducing the EF3 from 34% to 64%, which highlights that under local conditions, 10kgDCDha-1 (the recommended rate for commercial use in New Zealand) was not the optimum DCD rate to curb N2O emissions. The modelling of EF3 in this study also suggests that N mitigation should be given more attention when soil moisture is going to be high, which can be predicted with short-term weather forecasting. DCD feeding, for instance in autumn when cows are not lactating and the risk of N losses is high, could then be reduced by focusing mainly on those forecasted wet periods.

Efficiency and spectrum enhancement in a tapered free-electron laser amplifier.

We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using a tapered undulator. Output and spectra in the fundamental and third harmonic were measured versus distance for uniform and tapered undulators. With a 4% field taper over 3 m, a 300% (50%) increase in the fundamental (third harmonic) output was observed. A significant improvement in the spectra with the elimination of sidebands was observed using a tapered undulator. The experiment is in good agreement with predictions using the MEDUSA simulation code.

Nonlinear cross-phase modulation with intense single-cycle terahertz pulses.

We have demonstrated nonlinear cross-phase modulation in electro-optic crystals using intense, single-cycle terahertz (THz) radiation. Individual THz pulses, generated by coherent transition radiation emitted by subpicosecond electron bunches, have peak energies of up to 100 microJ per pulse. The time-dependent electric field of the intense THz pulses induces cross-phase modulation in electro-optic crystals through the Pockels effect, leading to spectral shifting, broadening, and modulation of copropagating laser pulses. The observed THz-induced cross-phase modulation agrees well with a time-dependent phase-shift model.

Experimental characterization of superradiance in a single-pass high-gain laser-seeded free-electron laser amplifier.

In this Letter we report the first experimental characterization of superradiance in a single-pass high-gain free-electron laser (FEL) seeded by a 150 femtosecond (FWHM) Ti:sapphire laser. The nonlinear energy gain after an exponential gain regime was observed. We also measured the evolution of the longitudinal phase space in both the exponential and superradiant regimes. The output FEL pulse duration was measured to be as short as 81 fs, a roughly 50% reduction compared to the input seed laser. The temporal distribution of the FEL radiation as predicted by a numerical simulation was experimentally verified for the first time.

First ultraviolet high-gain harmonic-generation free-electron laser.

We report the first experimental results on a high-gain harmonic-generation (HGHG) free-electron laser (FEL) operating in the ultraviolet. An 800 nm seed from a Ti:sapphire laser has been used to produce saturated amplified radiation at the 266 nm third harmonic. The results confirm the predictions for HGHG FEL operation: stable central wavelength, narrow bandwidth, and small pulse-energy fluctuation.

Surface-roughness wakefield measurements at brookhaven accelerator test facility.

An experiment has been carried out at the Brookhaven Accelerator Test Facility to investigate the effect of a surface-roughness wakefield in narrow beam tubes with artificially created bumps. The measurements show that the synchronous modes decay significantly due to the randomization of the roughness pattern. It is pointed out that this decay mechanism has not been investigated in the previous experiment at DESY and the investigators' conclusion does not apply for surface-roughness wakefields in real surfaces.

Sequestration of host plant carotenoids in the larval tissues of Helicoverpa zea.

To determine the cause of the unique yellow coloration in mandibular glands of soybean-fed Helicoverpa zea larvae, the accumulation of carotenoids in various tissues of last instar larvae fed soybean, cotton and tomato foliage was quantified. Five carotenoids were detected in the foliage of all host plants but at significantly different concentrations. Xanthophylls rather than carotenes were most likely to accumulate in larval tissues. Carotenoids accumulated at different rates and some were significantly affected by larval diet. Highest levels of carotenoid accumulation, notably lutein, were detected in the testes, followed by midgut epithelium, fat body and integument. The midgut epithelium contained the greatest and the testes the least diversity of carotenoid types. Low levels of lutein were detected in both labial and mandibular glands. Tomato foliage had the highest carotenoid content and caterpillar tissues fed these leaves often had the highest amounts of carotenoid. However, the accumulation of carotenoids did not protect larvae from antibiotic effects of tomato foliage because these caterpillars had the highest mortality and slowest growth rates of all the three host plants. Transport and absorption of lipid and oxidative stress may be some reasons for differential carotenoid accumulation.

Fournier gangrene associated with Crohn disease.

A 17-year-old boy presented with Fournier gangrene associated with previously undiagnosed Crohn ileocolitis. Fournier gangrene was managed by débridement, broad-spectrum antibiotics, and hyperbaric oxygen. A diverting ileostomy was performed before skin grafting and scrotal reconstruction. Microscopy of a full-layer surgical sample from the terminal ileum revealed granulomas with multinucleated histiocytes, consistent with Crohn disease. Crohn disease was treated with mesalamine, metronidazole, 6-mercaptopurine, and infliximab. The patient was discharged on hospital day 32. At 6-month follow-up, reconstruction of his scrotum had completely healed. Ostomy output was normal.

Cross-talk between the signal pathways for pathogen-induced systemic acquired resistance and grazing-induced insect resistance.

Reducing phenylpropanoid biosynthesis in transgenic tobacco compromises systemic acquired resistance (SAR) to tobacco mosaic virus, while increasing phenylpropanoid biosynthesis enhances SAR. Surprisingly, transgenic tobacco plants compromised in SAR exhibit more effective grazing-induced systemic resistance to larvae of Heliothis virescens, whereas induced insect resistance is compromised in transgenic plants with elevated phenylpropanoid levels. Levels of the phenylpropanoid-derived signal salicylic acid are directly correlated with overall phenylpropanoid biosynthesis in this series of transgenic plants. Moreover, while pathogen-induced SAR is almost completely compromised in salicylic acid-deficient plants expressing the bacterial nahG salicylate hydroxylase gene, these plants show enhanced grazing-induced insect resistance compared to wild-type. Hence, suppression of grazing-induced insect resistance is mediated at least in part by salicylic acid and likely reflects salicylic acid inhibition of the synthesis and action of the wound signal jasmonic acid. We propose that the dual functions of salicylic acid contribute to a signal poise which constrains constitutive expression of disease and insect resistance mechanisms, and reciprocally switches their selective activation.

A Nod factor-binding lectin is a member of a distinct class of apyrases that may be unique to the legumes.

Recent studies from our laboratory have found that a root lectin from the legume Dolichos hifloris is present on the root surface, binds rhizobial Nod factor and has apyrase activity. To assess the broader significance of this lectin/nucleotide phosphohydrolase (Db-LNP), we have cloned a second related cDNA (Db-apyrase-2) from D. hiflorus, as well as related cDNAs from the legumes Lotus japonicus and Medicago sativa, and from Arabidopsis thaliana, a non-legume. The deduced amino acid sequences of these apyrases were aligned with one another and with the sequences of other apyrases from plants, animals, yeast and protozoa. Phylogenetic analysis shows that Db-LNP has closely related orthologs only in other legumes, while Db-apyrase-2 is more closely related to apyrase sequences from non-leguminous plants. We also show that the orthologs of Db-LNP from M. sativa and Pisum sativum have carbohydrate binding activity. The results suggest that legume LNPs may represent a special class of apyrases that arose by gene duplication and subsequent specialization.

A nod factor binding lectin with apyrase activity from legume roots.

A lectin isolated from the roots of the legume, Dolichos biflorus, binds to Nod factors produced by rhizobial strains that nodulate this plant and has a deduced amino acid sequence with no significant homology to any lectin reported to date. This lectin also is an enzyme that catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside di- and triphosphates; the enzyme activity is increased in the presence of carbohydrate ligands. This lectin-nucleotide phosphohydrolase (LNP) has a substrate specificity characteristic of the apyrase category of phosphohydrolases, and its sequence contains four motifs characteristic of this category of enzymes. LNP is present on the surface of the root hairs, and treatment of roots with antiserum to LNP inhibits their ability to undergo root hair deformation and to form nodules on exposure to rhizobia. These properties suggest that this protein may play a role in the rhizobium-legume symbiosis and/or in a related carbohydrate recognition event endogenous to the plant.

Inverse relationship between systemic resistance of plants to microorganisms and to insect herbivory.

Pre-inoculation of plants with a pathogen that induces necrosis leads to the development of systemic acquired resistance (SAR) to subsequent pathogen attack [1]. The phenylpropanoid-derived compound salicylic acid (SA) is necessary for the full expression of both local resistance and SAR [2] [3]. A separate signaling pathway involving jasmonic acid (JA) is involved in systemic responses to wounding and insect herbivory [4] [5]. There is evidence both supporting and opposing the idea of cross-protection against microbial pathogens and insect herbivores [6] [7]. This is a controversial area because pharmacological experiments point to negative cross-talk between responses to systemic pathogens and responses to wounding [8] [9] [10], although this has not been demonstrated functionally in vivo. Here, we report that reducing phenylpropanoid biosynthesis by silencing the expression of phenylalanine ammonialyase (PAL) reduces SAR to tobacco mosaic virus (TMV), whereas overexpression of PAL enhances SAR. Tobacco plants with reduced SAR exhibited more effective grazing-induced systemic resistance to larvae of Heliothis virescens, but larval resistance was reduced in plants with elevated phenylpropanoid levels. Furthermore, genetic modification of components involved in phenylpropanoid synthesis revealed an inverse relationship between SA and JA levels. These results demonstrate phenylpropanoid-mediated cross-talk in vivo between microbially induced and herbivore-induced pathways of systemic resistance.

Lack of an association between insulin-like growth factor-I and body composition, muscle strength, physical performance or self-reported mobility among older persons with functional limitations.

OBJECTIVE: The hypothesis that decreased growth hormone (GH) secretion contributes to the functional decline that occurs with aging is far from substantiated. There have been few studies addressing the distribution and correlates of IGF-I, an indicator of GH activity, in nonclinical populations. As part of a growth hormone intervention trial, we examined the cross-sectional relations between IGF-I levels and multiple measures of physical function, body composition, and strength in a group of older men and women exhibiting mild to moderate reductions in measured physical performance. METHODS: Using a variety of advertising techniques, 155 older subjects were recruited from a metropolitan area to participate in a growth hormone and exercise intervention study. At baseline, all subjects had blood drawn for IGF-I and underwent testing of body composition using dual X-ray absorptiometry, muscle strength using isokinetic dynamometry, and functional assessment using timed performance measures and self-report. Associations between levels of IGF-I, body composition, strength, and physical function were assessed after dividing men and women separately into tertiles of IGF-I as well as treating IGF-I as a continuous variable. RESULTS: Men had higher IGF-I levels than women, and a significant inverse correlation was observed between age and IGF-I in men (r=-0.29, P=.009). There were no clear trends for associations between tertiles of IGF-I, and any of the variables tested. Linear regression models with IGF-I treated as a continuous measure were not associated significantly with any of the measures of physical function, body composition, or strength (all P > 0.05). CONCLUSIONS: In conclusion, although IGF-I levels declined with age in men, these data did not demonstrate an association between IGF-I and measures of muscle strength, body composition, or physical functioning. These findings support the growing body of evidence that IGF-I levels may not be an indicator of growth hormone activity in older persons.

Use of magnetic resonance imaging scanning in adrenocortical carcinoma with vena caval involvement.

We report on 2 cases of an adrenocortical carcinoma with vena caval involvement. Preoperative evaluation included a magnetic resonance imaging (MRI) scan confirming the presence of vena caval involvement. Extremely precise detail of the vena caval tumor thrombus was very helpful in preparing for the surgical extirpation. MRI detail far outweighed what was seen on the computed tomography scan and venacavogram. The MRI scan correlated exactly with what was found surgically. Although MRI scanning has been used to evaluate renal tumors with vena caval extension, few cases have been reported with similar adrenal tumors.

Physical and functional assessment of the elderly stroke patient.

A functionally oriented approach to acute stroke care should take place in parallel with traditional medical management, since the medical care provided during the first days and weeks after a stroke affects the patient's ultimate disability status. The components of the functionally oriented approach include a comprehensive history and physical examination, through which information is obtained on current disabilities and abilities, risk factors for common poststroke complications, psychologic and social resources, and environmental barriers that preclude maximal functioning.

Recurrence of breast carcinoma following immediate reconstruction: a 13-year review.

To evaluate the effect of immediate reconstruction on the incidence, location, detection, and treatment of recurrent breast cancer, a review of 306 patients operated on according to a standard protocol during the 10-year period 1979 through 1988 was performed. Reconstruction techniques included submuscular implants (207), tissue expanders (84), and musculocutaneous flaps (15). During a minimum follow-up period of 3 years with a mean of 6.4 years, 60 patients (19.6 percent) developed recurrent disease, at a mean interval to recurrence of 31 months. The first locations of recurrences were local (16), regional (11), and systemic (33). Recurrence rates by stage included stage I, 7 patients (5.2 percent); stage II, 45 patients (32.1 percent); and stage III, 8 patients (40 percent). It was not possible to include comparisons with internal control groups of patients in our institution who were not reconstructed or who had delayed reconstructions, thereby preventing conclusions based on such comparisons. Our recurrence data are similar to literature reports of recurrence rates in patients who were not reconstructed after mastectomy. Detection and treatment of recurrences were not inhibited by the reconstructions. When radiation therapy was used in the treatment of local recurrences, the development of symptomatic capsular contracture was recorded in 58 percent of the patients.

Screening for older persons.

Our screening recommendations for older individuals are outlined in Figures 1 and 2. Our recommendations are parsimonious for two reasons. First, we are concerned about the potential harm of using unproven screening strategies. Second, when there are effective screening strategies, many of the target group are not being adequately screened. We agree with Clayman that it is much wiser to invest our scarce resources on improving the screening rates for clearly efficacious interventions before investing in strategies where efficacy is in question.

Synchrotron radiation sources and condensers for projection x-ray lithography.

The design requirements for a compact electron storage ring that could be used as a soft-x-ray source for projection lithography are discussed. The design concepts of the x-ray optics that are required for collecting and conditioning the radiation in divergence, uniformity, and direction to illuminate the mask correctly and the particular x-ray projection camera used are discussed. Preliminary designs for an entire soft-x-ray projection lithography system that uses an electron storage ring as a soft-x-ray source are presented. It is shown that, by combining the existing technology of storage rings with large collection angle condensers, a powerful and reliable source of 130-A photons for production line projection x-ray lithography is possible.