Digestibility and nitrogen utilization of three beef cattle rations containing corn silage ensiled with limestone and varying levels of urea

The purpose of this experiment was to compare digestibility and nitrogen utilization of three beef cattle rations containing one of three levels of urea in limestone corn silage. The experiment was designed to determine if adaptation to urea nitrogen utilization occurs when these rations are fed, and if diethylstilbestrol has an effect on the rate of this adaptation. Two digestion and nitrogen metabolism trials were conducted separately. The experimental silage treatments were as follows:Treatment 1—0.5 percent urea silage: corn green chop plus5 kilograms of urea (281% crude protein) and 5 kilograms ground limestone per metric ton. Treatment 2--0.75 percent urea silage: corn green chop plus 7.5 kilograms of urea (281% crude protein) and 5 kilograms ground limestone per metric ton. Treatment 3 -- 1.0 percent urea silage: corn green chop plus10 kilograms of urea (281% crude protein) and 5 kilograms ground limestone per metric ton. In both trials, there were four steers per treatment and each steer was offered a constant amount of concentrate mixture (corn and cottonseed meal) together with approximately 80 percent of the amount of urea corn silage which was consumed by the animal with the lowest feed intake toward the end of the preliminary period. The three rations were calculated to supply the recommended crude protein requirements. As the nitrogen content in the urea silages increased, the proportion of cottonseed meal in the concentrate mixture was reduced to make the threerations approximately isonitrogenous. The first two steers of each treatment group were implanted with 2k mg. of diethylstilbestrol.During the period between the two trials, the experimental steers were continued on their respective rations. The second trial was conducted the same as the first.The results from this study were as follows: 1. The digestion coefficients of dry matter and energy were slightly higher for the 0.5 percent urea ration but no significant differences were observed among treatments in both trials. 2. Digestion coefficients of crude protein were significantly higher (P\u3c.05) for the 1.0 percent ration in the first trial, and higher in the second trial but not significantly so. Crude protein digestibility between the 0.75 and 0.5 percent urea silage rations for both trials was not significantly different. The higher apparent crude protein digestibility of the 1.0 percent silage ration may have been caused by the higher crude protein equivalency in that ration. 3. Estimated total digestible nutrient values in the 0.5 percent\irea silage ration were significantly higher (P\u3c.05) than in the 0.75and 1.0 percent silage rations in both trials. There were no significant differences in TDN values between the 0.75 and 1.0 percent urea silage ration in both trials. The higher estimated TDN values of the 0.5 percent silage ration was probably not related to its lower urea content but to the decreased dry matter intake of that ration. 4. In both trials, absorbed nitrogen retained data indicated that the 1.0 percent urea silage ration was utilized significantly-better (P\u3c.Q5) than the 0.5 percent urea silage ration. The general trend in both trials was an increase in retention of absorbed nitrogen with increased urea levels in the ration. This increase of retention of absorbed nitrogen with increased urea levels in the rations was probably not related to the amo-unt of urea in the rations. 5 In both trials, net protein utilization was significantly higher in the 1.0 percent urea silage ration and these values generally followed the same trend as absorbed nitrogen retained values. 6 The data from both trials indicated that no adaptation response for nitrogen utilization occurred in rations where urea supplied30 percent or less of the crude protein equivalency. 7 Since there was no adaptation response, diethylstilbestrol had no effect upon shortening the adaptation period. However, thosesteers implanted with diethylstilbestrol showed improved weight gains

Spectroscopic, Electronic, and Mechanistic Studies of Silicon Surfaces Chemically Modified with Short Alkyl Chains

The chemical, structural, and electronic properties of semiconductor surfaces are known to strongly influence the energetics at semiconductor interfaces. Inexpensive and scalable wet chemical modification of semiconductor surfaces provides a means to impart a desired functionality at semiconductor interfaces for the development of new devices based on precise and cost-effective chemistry. This thesis is composed of three studies that focused on identifying the spectroscopic, electronic, and mechanistic properties of reactions at Si surfaces. First, ethynyl- and propynyl-terminated Si(111) surfaces were prepared and characterized by vibrational and photoelectron spectroscopy as well as electrochemical scanning-tunneling microscopy. Ethynyl-terminated Si(111) exhibited ≡C−H, C≡C, Si−C stretching signals and a fractional monolayer (ML) coverage (Φ) of ΦSi−CCH = 0.63 ± 0.08 ML and ΦSi−OH = 0.35 ± 0.03 ML. Propynyl-terminated Si(111) showed (C−H)CH3 bending, Si−C stretching, and C≡C stretching with ΦSi−CCCH3 = 1.05 ± 0.06 ML. Deprotonation of ethynyl-terminated Si(111) surfaces formed a unique surface-bound lithium acetylide that acted as nucleophile. This work provides definitive spectroscopic and microscopic evidence for the covalent attachment of ethynyl and propynyl groups to the Si(111) surface. Second, Si(111) surfaces were modified with 3,4,5-trifluorophenylacetylene (TFPA) groups to impart a positive dipole at the Si(111) surface. This negative surface dipole provides the necessary band-edge shift at the Si surface to maximize the interface between p-type Si and the proton reduction half reaction. Vibrational and photoelectron spectroscopy provided evidence for the attachment of TFPA groups to the Si(111) surface. Mixed methyl/TFPA monolayers were prepared and characterized using electrochemical and photoelectrochemical methods to show that the band-edge positions and open-circuit voltages were shifted positive with increasing fractional TFPA coverage on the surface. This work demonstrates that monolayer chemistry can be used to manipulate the band-edge positions of Si surfaces as a function of surface composition. Finally, mechanistic studies of the reaction of liquid methanol with hydride-terminated Si(111) surfaces in the presence of an oxidant were carried out. Vibrational and photoelectron spectroscopy showed that acetylferrocenium, ferrocenium, and dimethyl-ferrocenium could serve as oxidants to promote an increased rate of methoxylation of the H–Si(111) surface in the dark. Illumination of intrinsic and n-type surfaces resulted in an increased rate of methoxylation, resulting from a positive shift in energy of the electron quasi-Fermi level in the presence of light. The results are described in the context of a kinetic charge transfer formalism that is consistent with the experimentally observed results. This work provides a general framework to describe the kinetics of charge transfer reactions that occur on semiconductor surfaces.</p

Outcomes Experienced by Patients Presenting With Ventral Hernias and Morbid Obesity in a Surgical Clinic

Surgeons generally agree that morbid obesity is a contraindication to ventral hernia repair surgery due to risk of adverse outcomes. The purpose of this study was to describe the experience of patients with ventral hernia complicated by morbid obesity by reviewing a population of patients that were seen by a surgical service to determine the characteristics of those patients that had favorable and unfavorable outcomes. A retrospective medical record review was conducted of new patients with ventral hernias and morbid obesity (body mass index (BMI ) ≥ 40 kg/m2) seen by one surgical service over a two and a half-year time period. Clinical characteristics were noted, and surgical approach and clinical outcomes were noted for patients that had hernia repair. Patients that did not return were attempted to be contacted for a survey. A total of 79 new patients with ventral hernias and morbid obesity were seen during the time period described. Eighteen patients did not follow up after initial visit; telephone surveys were conducted with six subjects. Morbidly obese patients with ventral hernias that were amenable to laparoscopic repair had favorable outcomes. Patients that had hernia repair that had met goal weight were few in numbers. Patients that had open hernia repair had increased rate of surgical site issues compared to patients that had laparoscopic repairs. Follow up surveys, because few in number, provided anecdotal information. Further research is needed to understand best practices for patients with ventral hernias complicated by morbid obesity

Variability in Azygospore Production among Entomophaga maimaiga Isolates

This study describes in vitro and in vivo azygospore production by nine isolates of Entomophaga maimaiga, a fungal pathogen of the gypsy moth, Lymantria dispar. The three E. maimaiga isolates that consistently produced azygospores in vitro were also strong producers of azygospores in vivo. However, two additional isolates that were strong azygospore producers in vivo did not produce azygospores in vitro. Isolates that produced azygospores in vitro produced both conidia and azygospores more frequently in vivo than isolates not producing azygospores in vitro. In vitro azygospore production varied over time as well as by isolate. After \u3e2 years of cold storage, while three isolates continued in vitro azygospore production, three isolates no longer produced azygospores in vitro

Corrected QT Interval in Children With Brain Death

Prolongation of the QT interval is a well-documented finding in adults with severe brain injury. However, QT prolongation has not been well documented in the pediatric population with brain injury. Our objective was to determine the range of QT intervals in children with the diagnosis of brain death, hypothesizing that the QT interval corrected for heart rate (QTc) is longer in this population than in a normal population. All previously healthy children (<18 years) dying in our hospital from 1995 to 2007 with a diagnosis of brain death and at least one electrocardiogram (ECG) with normal anatomy by echocardiogram were included. Admission details, past medical and family history, demographic data, and laboratory data were collected. The QT and preceding RR intervals from three sinus beats on a standard 12-lead ECG were measured. The QTc was calculated with the Bazett method, and the values were averaged. Thirty-seven patients met inclusion criteria. Five had event histories concerning for possible underlying rhythm disturbances; data analysis was performed with and without these patients. The QTc data were normally distributed. The mean (SD) QTc for the entire cohort was 452 (61) ms. Excluding the five patients, it was 449 (62) ms. On multivariate analysis, sex (QTc female < male) and hypokalemia were associated with QTc prolongation. QTc in children with brain death is normally distributed but significantly longer than QTc in normal children. Until rapid genetic testing for channelopathies is universally available, our findings suggest that potential pediatric cardiac donors with isolated prolongation of the QTc in this setting may be acceptable in the absence of other exclusionary criteria

Induction of Systemic Acquired Resistance in Cotton Foliage Does Not Adversely Affect the Performance of an Entomopathogen

Baculoviral efficacy against lepidopteran larvae is substantially impacted by the host plant. Here, we characterized how baculoviral pathogenicity to cotton-fed Heliothis virescens larvae is affected by induction of systemic acquired resistance (SAR). Numerous studies have shown that SAR induced by the plant elicitor benzo-(1,2,3)-thiadiazole-7- carbothioic acid S-methyl ester (BTH) can protect against plant pathogens, but reports on the impacts of SAR on chewing herbivores or on natural enemies of herbivores are few. We found that BTH application significantly increased foliar peroxidase activity, condensed tannin levels, and total phenolic levels but did not alter dihydroxyphenolic levels. Consumption of BTH-treated foliage did not influence H. virescens pupal weight or larval mortality by the microbial control agent Autographa californica multiple nucleopolyhedrovirus any more than did consumption of untreated foliage. Thus, activation of SAR, although it did not protect the plant against a chewing herbivore, also did not reduce the effect of a natural enemy on a herbivore, indicating that SAR and microbial control agents may be compatible components of integrated pest management

Comparing Two Methods for Quantifying Soil-borne Entomophaga maimaiga Resting Spores

To improve usability of methods for quantifying environmentally persistent entomophthoralean resting spores in soil, we modified and tested two methods using resting spores (azygospores) of the gypsy moth pathogen Entomophaga maimaiga. Both methods were effective for recovering resting spores at concentrations \u3e100 resting spores/g dry soil. While a modification of a method originally described by Weseloh and Andreadis (2002) recovered more resting spores than a modified method based on Percoll density gradients, the ability to estimate true densities from counts was similar for both methods. Regression equations are provided for predicting true resting spore densities from counts, with R 2 values for both methods P0.90

Complete Genome Sequences of Four Putatively Antibiotic-Producing Bacteria Isolated from Soil in Arkansas, USA

Soil bacteria can be a valuable source of antimicrobial compounds. Here, we report the complete genomes of four soil bacteria that were isolated by undergraduate microbiology students as part of a course-based research experience. These genomes were assembled using a hybrid approach combining paired-end Illumina reads with Oxford Nanopore Technologies MinION reads

Emergent Fungal Entomopathogen Does Not Alter Density Dependence in a Viral Competitor

Population cycles in forest Lepidoptera often result from recurring density-dependent epizootics of entomopathogens. While these systems are typically dominated by a single pathogen species, insects are often infected by multiple pathogens, yet little is known how pathogens interact to affect host dynamics. The apparent invasion of northeastern North America by the fungal entomopathogen Entomophaga maimaiga some time prior to 1989 provides a unique opportunity to evaluate such interactions. Prior to the arrival of E. maimaga, the oscillatory dynamics of host gypsy moth, Lymantria dispar, populations were apparently driven by epizootics of a nucleopolyhedrovirus. Subsequent to its emergence, E. maimaiga has caused extensive mortality in host populations, but little is known about how it has altered multigenerational dynamics of the gypsy moth and its virus. Here we compared demographic data collected in gypsy moth populations prior to vs. after E. maimaiga\u27s invasion. We found that the recently invading fungal pathogen virtually always causes greater levels of mortality in hosts than does the virus, but fungal mortality is largely density independent. Moreover, the presence of the fungus has apparently not altered the gypsy moth–virus density-dependent interactions that were shown to drive periodic oscillations in hosts before the arrival of the fungus

Evaluation of sputtered nickel oxide, cobalt oxide and nickel–cobalt oxide on n-type silicon photoanodes for solar-driven O₂(g) evolution from water

Thin films of nickel oxide (NiO_x), cobalt oxide (CoO_x) and nickel–cobalt oxide (NiCoO_x) were sputtered onto n-Si(111) surfaces to produce a series of integrated, protected Si photoanodes that did not require deposition of a separate heterogeneous electrocatalyst for water oxidation. The p-type transparent conductive oxides (p-TCOs) acted as multi-functional transparent, antireflective, electrically conductive, chemically stable coatings that also were active electrocatalysts for the oxidation of water to O₂(g). Relative to the formal potential for water oxidation to O₂, E^(o′)(O₂/H₂O), under simulated Air Mass (AM)1.5 illumination the p-TCO-coated n-Si(111) photoanodes produced mutually similar open-circuit potentials of −270 ± 20 mV, but different photocurrent densities at E^(o′)(O₂/H₂O), of 28 ± 0.3 mA cm⁻² for NiO_x, 18 ± 0.3 mA cm⁻² for CoO_x and 24 ± 0.5 mA cm⁻² for NiCoO_x. The p-TCOs all provided protection from oxide growth for extended time periods, and produced stable photocurrent densities from n-Si in 1.0 M KOH(aq) (ACS grade) under potential control at E^(o′)(O₂/H₂O) for >400 h of continuous operation under 100 mW cm−2 of simulated AM1.5 illumination