Texas A&M University-Kingsville: AKM Digital Repository
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1689 research outputs found
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Determining if sulfur content in market lamb diets influences ground lamb flavor
No full textTo determine if dietary sulfur impacts flavor, ten Dorper wethers were placed in individual pens and randomly assigned to be fed a control or high sulfur diet (control with 0.35% elemental sulfur on a DM basis). Lambs were fed a rationed diet at 3.5 % of their body weight on an as-fed basis, with an initial 1.5-week adjustment period. The treatment diet group received elemental sulfur at 0.35% of their body weight on a DM basis. After 54 days of the feeding trial the Dorpers were harvested via common industry methods. Carcasses were chilled for 24 h, split into two sides with one side fabricated, the square-cut shoulder wet aged, while the other side dry aged for 21 days then fabricated. After aging, shoulders were fabricated into 80% lean and 20% fat ground lamb patties (0.103 kg/patty), vacuum sealed, and frozen. There were no differences (P > 0.05) between treatments in growth performance or carcass characteristics. When patties were served fresh to a trained taste panel there was no difference (P > 0.05) in lamb flavor between treatments, but treatment patties had more (P 0.05) in off-flavor between treatments was observed
Investigation of fast pyrolysis product distribution of Rio Red Grapefruit waste and related lignocellulose model compounds
No full textThe use of Rio Red grapefruit processing waste (GPW) as a lignocellulosic feedstock candidate for the production of value-added chemicals via fast pyrolysis was investigated by combining statistical design of experiments with product distribution data generated from a bench-scale CDS model 5200 pyroprobe system coupled to an Agilent 6890 GC/MS analytical engine. To quantify the interplay between the fast pyrolysis process variables and the product distribution, monomeric and dimeric cellulosic compounds were used as model species. Box-Behnken statistical design and other related statistical designs were used to determine the potential interactions between heating rate (HR, oC/ms), temperature (T, oC), and pyrolysis time (τ, s) and their effect on product yields. Significant interactions were shown to exist between these process variables. In particular, it was shown that the optimal pyrolysis product distribution could be identified for particular values for the heating rate, temperature, and pyrolysis heating time.
The fast pyrolysis product distribution of GPW was also investigated by using calibrated temperature set points obtained from optimization studies using cellulosic model compounds. To perform the required gas chromatography-based analytical measurements, a dual-column tandem Py-GC/MS-FID-TCD analytical method was developed for simultaneous qualitative and quantitative analysis of the pyrolysis product gases. It was discovered that the GPW pyrolysis vapor composition was dominated by phenolic compounds, which could lead to a highly unstable liquid product. These optimization studies lead to the identification of preferred process conditions to minimize the yield of phenols.
A new experimental method for obtaining time-resolved fast pyrolysis data on the millisecond scale was also proposed to overcome a limitation associated with existing pyroprobe-based systems that are largely based upon final product analysis. The hydrodynamic characteristics of the modified pyroprobe design were modeled by using CFD approaches. It was shown that the modified pyroprobe would be ideal for interrogation of the primary fast pyrolysis reactions by mapping the time evolution profiles of the nascent reactive/stable intermediates using a suitable detector or fast analyzer for the gas-phase intermediates.
The research findings identified in this work can be used as progress toward identifying a wide range of optimal conditions to convert GPW to various value-added products with a high degree of selectivity. Also, the modified pyroprobe design for time-resolved measurements has the potential to provide molecular level mechanistic information that can form the basis for unraveling intricate and complex fast pyrolysis reaction mechanisms for a variety of individual molecules as well as complex feedstocks
Study of coordination chemistry of gold(I) complexes containing a hemilabile bisphosphine monoxide ligand
No full textIn recent years, gold(I) complexes have been found to be suitable compounds for use in catalytic systems for various functionalization reactions. Neutral complexes with the structure [LAuX], containing a neutral ligand, L and a coordinating anion, X have been studied at length, but focus has shifted to synthesis and characterization of cationic gold(I) complexes containing two neutral ligands and a non-coordinating anion, [LAuL’]X. The objective of this study is the synthesis and characterization of new cationic gold(I) complexes [Au(PPO)L]X containing 1,2-bis(diphenylphosphino)benzene monoxide (PPO) as a hemilabile ligand. Since in previous studies alkenes, alkynes, and nitrile gave thermally unstable complex, it was interesting to investigate PPh3, DMSO, and SMe2 as stronger P- and S-donor ligands. The chloro gold(I) complex [Au(PPO)Cl] was used as starting compound, which was reacted with AgSbF6 in the presence of the donor ligand to afford [Au(PPO)L]SbF6 by chloride abstraction. Three new cationic gold(I) complexes, [Au(PPO)(PPh3)]SbF6, [Au(PPO)(DMSO)]SbF6, and [Au(PPO)(SMe2)]SbF6, were all isolated with very good yield. Evidence of thermal instability was observed for each of the new complexes, however they were stable enough to be characterized by 1H, 31P and 13C NMR spectroscopy, FTIR spectroscopy, ESI mass spectrometry and X-ray single crystal structure analysis. With these analytical methods, the identity of each complex was verified, showing some impurities or decomposition products due to their moderate thermal stability. With these studies three new derivatives of the complex type [Au(PPO)L]X were successfully synthesized, whose catalytic activity for organic transformation may be tested in future studies
Field evaluation of different citrus scion and rootstock combinations for toleranc to Candidatus liberibacter asiaticus
No full textHuanglongbing (HLB) is a devastating disease of citrus that is associated with the Asian citrus psyllid vectored bacterium, Candidatus Liberibacter asiaticus (CLas). All Citrus species are susceptible to HLB and exhibit several levels of tolerance/resistance when grafted on different citrus rootstocks. Six hybrid rootstocks (US802, US812, C22, X639, US942, US897) were tested along with the commonly used sour orange (SO) rootstock under South Texas growing conditions in a field trial with 5 years old sweet orange cv. Marrs (MSO) and grapefruit, cv. Rio Red (RRG), grafted onto each of the seven rootstocks and planted in a randomized complete block design. A comparative study on two nucleic acid extraction protocols for an alternative to a commercial kit and an estimation of the CLas genome equivalence in each rootstock-scion combination was done using foliage from scion. Field study showed seasonal variation in HLB incidence as visually observed while molecular diagnosis for CLas presence in the symptomatic and asymptomatic foliage of all experimental trees in summer, fall, and winter 2021 also varied. Statistical analysis showed grapefruit cultivars on the rootstocks US942 and sour orange had the lowest CLas genome equivalence while C22 had the highest for scions of sweet oranges, and US812 had the lowest bacterial load therefore indicating that here was a strong cultivar by rootstock interaction. The highest CLas genome equivalence was recorded in fall for grapefruits but the seasonal impact was not significant for sweet oranges. These results will be useful for growers to determine the best scion/rootstock selection for HLB management under Texas growing conditions
Seismic structure and gas hydrate studies on the Southern cascadia margin using mutichannel seismic data
No full textThe U.S. Geological Survey collected multichannel seismic data off Cape Blanco in 1994 to study the crustal structure. In this study, one of the margin perpendicular lines from this data was used to obtain the seismic structure. Seismic data processing and tomographic velocity analysis were used to interpret the seismic velocities of the subsurface. Additionally, sonic velocity and density information from ten industry exploratory wells drilled in the 1960s in southwest Oregon were used to understand the subsurface structure.
The migrated seismic section revealed a thrust-fold pattern within intensely deformed sediments ~0.5 s thick in the Cascadia basin related to horizontal shortening and compression associated with the ongoing subduction of the Gorda plate. The top of the crust appears fractured with a horst and graben structure. Interval velocities observed range between 1.5 – 2.5 km/s within sediments of the Cascadia basin, and 3.0 – 3.5 km/s at the top of the crust. The low interval velocities on top of the crust likely indicate fractured volcanic rocks. A prominent bottom simulating reflector (BSR) at 270 ms – 537 ms depth is also observed within the shallow sediment section of the accretionary wedge. This BSR spans a ~10 km distance along the continental slope with hydrated sediment velocities of 1.8-2.0 km/s. Landward of the migrated section, two low-velocity zones with velocities ~1.5–2.0 km/s were observed up to depths of 4 s likely indicating possible hydrocarbons. Between the low-velocity zones, a broad anticlinal structure was observed within the shallow shelf sediments with velocities up to 3.5 km/s indicating fractured volcanics. The results of this study have important implications to understand natural hazards and hydrocarbon potential of this region
Characterization of cell lines expressing Bcl-2 for the functional analysis of BMRP
No full textApoptosis plays a complementary and opposite role to that of mitosis and is vital to the natural development of and maintenance of tissue homeostasis in adult metazoans (animals). Aberrant apoptotic activity has been implicated in the pathogenesis of various human diseases such as cancer, autoimmune disorders, neurodegenerative diseases (such as Alzheimer’s and Parkinson’s), infertility, as well as cardiac arrest and stroke damage. Cells undergoing apoptosis can be identified by the distinct changes in morphology that occur including cell shrinkage, plasma membrane blebbing, chromatin condensation, and finally cell fragmentation into membrane-bound ultra-structures known as apoptotic bodies. In previous studies the proteins of the B-cell lymphoma/leukemia-2 (Bcl-2) family -have been identified as regulators of apoptotic activity and the family is comprised of pro- and anti-apoptotic proteins. Members of the Bcl-2 family of proteins may contain up to four Bcl-2 homology (BH) domains and it is frequently observed that anti-apoptotic members contain all four BH domains. Bcl-2 was first characterized in B-cell lymphomas and leukemias, which is where the name for the protein is derived. It was through the study of B-cell lymphomas and leukemias that Bcl-2 was characterized as having anti apoptotic activity. To gain further insight into the anti-apoptotic function of Bcl-2 and how this function is regulated, a yeast Two-Hybrid screen was conducted with the goal of identifying novel proteins that interact with Bcl-2. This yeast Two-Hybrid approach led to the identification of Bcl-2 interacting Mitochondrial Ribosomal Protein (BMRP), also known as MRPL41, as a novel Bcl-2 binding partner. Functional studies of BMRP have shown that it induces apoptosis in mammalian cells. The aim of this research is to continue the characterization of the regions of BMRP that are responsible for its pro-apoptotic activity through the use of NIH/3T3 cells that stably express Bcl-2 so the apoptotic effects of BMRP on NIH/3T3 cells can be analyzed. Previous functional analyses performed in our laboratory with a variety of BMRP mutants have delimited the region of BMRP required for its pro-apoptotic function to the amino (N)-terminal two-thirds of the protein. NIH/3T3 stable transfectants that stably express two different Green Fluorescent Protein (GFP)/Bcl-2 fusion proteins have been generated and characterized. Expression analyses have been conducted to further characterize the regions of BMRP required for its interaction with Bcl-2. The knowledge gained in these studies will be utilized to design additional mutants to further delimit the pro-apoptotic region of BMRP as well as those needed for its interaction with Bcl-2
Physical development of Anglo and Spanish-culture school boys and girls, ages 13-18 inclusive
No full textA. PREVIOUS STUDIES
1. KRAMME’S STUDY (17)
In his research, a COMPARISON OF ANGLO-CULTURE WITH SPANISH-CULTURE ELEMENTRY STUDENTS IN PHYSICAL DEVELOPMENT AS DETERMINED BY HEIGHT, WEIGHTAND VITAL CAPCITY MEASURMENTS, Kramme found that there is a statistically significant difference in physical development at certain age levels. In this research Kramme measured height in inches, weight in pounds, vital capacity in cubic inches, and comparisons were made between computed means
Diagnostic study of third grade reading difficulties with suggestions for remedial instruction
No full textShould teaching of reading be improved? “Fully 50 per cent of our adult population cannot read with ease and understanding.” states Dr. Williams S. Gary in reporting a recent investigation. (13.84) Dr. Gates reports the following statistics with respect to the status of reading disability in the American school
Some amphibia and reptilia of Kleberg County
No full textTwo classes, Amphibia and Reptilia, of the phylum Chordate, subphylum Vertebrate, are dealt with in this thesis. The Amphibia represent a class of vertebrate animals occupying a position between the Pisces and Reptilia, the Reptilia between the Amphibia and Aves and Mammals
A case study of Benavides High graduates, 1923-38
No full textThe character of the American secondary school has in the last forty years undergone a tremendous change (7,419). The increase of the number of High Schools has been no more remarkable then the development of the curriculum (7,419)