Department of Chemical & Biological Engineering

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Accessing the main-group metal formyl scaffold through CO-activation in beryllium hydride complexes
(Nature Portfolio, 2022) Hadlington, Terrance J.; Szilvasi, Tibor; Technical University of Munich; University of Alabama Tuscaloosa
Carbon monoxide (CO) is an indispensable C1 building block. For decades this abundant gas has been employed in hydroformylation and Pausen-Khand catalysis, amongst many related chemistries, where a single, non-coupled CO fragment is delivered to an organic molecule. Despite this, organometallic species which react with CO to yield C1 products remain rare, and are elusive for main group metal complexes. Here, we describe a range of amido-beryllium hydride complexes, and demonstrate their reactivity towards CO, in its mono-insertion into the Be-H bonds of these species. The small radius of the Be2+ ion in conjunction with the non-innocent pendant phosphine moiety of the developed ligands leads to a unique beryllium formyl complex with an ylidic P-C-CO fragment, whereby the carbon centre, remarkably, datively binds Be. This, alongside reactivity toward carbon dioxide, sheds light on the insertion chemistry of the Be-H bond, complimenting the long-known chemistry of the heavier Alkaline Earth hydrides. Stoichiometric carbon monoxide insertion processes leading to metal-formyl complexes are scarce, even for transition metals. Here, light is shed on the underexplored chemistry of beryllium hydrides leading to a stable example of a main group metal-formyl complex.
Advanced solvents for CO2 separation applications
(University of Alabama Libraries, 2016) Flowers, Brian Steven; Bara, J. E.; University of Alabama Tuscaloosa
The objective of this dissertation is to advance the understanding of several novel solvents for CO2 capture and separation applications. Many of the solvents investigated were imidazole based, as these compounds are highly tunable, neutral, and less expensive analogs to imidazolium based ionic liquids (ILs). While much is known about the physical properties of ILs, the physical properties of these neutral compounds have not been researched as thoroughly, and so there is a need to explore these compounds as potential CO2 capture media. It has been further proven that the most effective means of predicting CO2 capture performance in imidazole based compounds is by examining the fractional free volume (FFV) using a molecular simulation program like COSMOTherm. Other non-imidazole based physical solvents were synthesized and compared to commercially available processes. 1,2,3-Trimethyoxypropane (1,2,3 TMP) was found to compare favorably with regard to CO2 absorption and viscosity to the current industry standard for CO2/CH4 pre-combustion separation techniques, Selexol, while being significantly less toxic. Chemical solvents for post-combustion CO2 capture were also investigated. It was determined that changing the substituents on 1-(3-aminopropyl)imidazole increases the CO2 solubility by increasing the basicity of the imidazole ring. The advantages in vapor pressure of these substituted aminopropylimidazole over traditionally used alkanolamines could potentially provide massive operational savings by reducing solvent losses through evaporation and increased solvent life.
Amelioration of Alzheimer's disease pathology by mitophagy inducers identified via machine learning and a cross-species workflow
(Nature Portfolio, 2022) Xie, Chenglong; Zhuang, Xu-Xu; Niu, Zhangming; Ai, Ruixue; Lautrup, Sofie; Zheng, Shuangjia; Jiang, Yinghui; Han, Ruiyu; Sen Gupta, Tanima; Cao, Shuqin; Lagartos-Donate, Maria Jose; Cai, Cui-Zan; Xie, Li-Ming; Caponio, Domenica; Wang, Wen-Wen; Schmauck-Medina, Tomas; Zhang, Jianying; Wang, He-ling; Lou, Guofeng; Xiao, Xianglu; Zheng, Wenhua; Palikaras, Konstantinos; Yang, Guang; Caldwell, Kim A.; Caldwell, Guy A.; Shen, Han-Ming; Nilsen, Hilde; Lu, Jia-Hong; Fang, Evandro F.; Wenzhou Medical University; University of Oslo; Oujiang Laboratory; University of Macau; Sun Yat Sen University; Athens Medical School; National & Kapodistrian University of Athens; Royal Brompton Hospital; Imperial College London; University of Alabama Tuscaloosa; University of Alabama Birmingham; National University of Singapore; Zhengzhou University
A reduced removal of dysfunctional mitochondria is common to aging and age-related neurodegenerative pathologies such as Alzheimer's disease (AD). Strategies for treating such impaired mitophagy would benefit from the identification of mitophagy modulators. Here we report the combined use of unsupervised machine learning (involving vector representations of molecular structures, pharmacophore fingerprinting and conformer fingerprinting) and a cross-species approach for the screening and experimental validation of new mitophagy-inducing compounds. From a library of naturally occurring compounds, the workflow allowed us to identify 18 small molecules, and among them two potent mitophagy inducers (Kaempferol and Rhapontigenin). In nematode and rodent models of AD, we show that both mitophagy inducers increased the survival and functionality of glutamatergic and cholinergic neurons, abrogated amyloid-beta and tau pathologies, and improved the animals' memory. Our findings suggest the existence of a conserved mechanism of memory loss across the AD models, this mechanism being mediated by defective mitophagy. The computational-experimental screening and validation workflow might help uncover potent mitophagy modulators that stimulate neuronal health and brain homeostasis.
Appendices to: Addressing the importance of STEM to Public Science communication in engineering formation: an analysis of an educational innovation for an upper-level chemical engineering health and safety course
(2024) Simpson, Lance Michael; VanDyke, Matthew S.; Koh, Amanda S.
STEM-to-public science communication is recognized as an important skill, but a pedagogical framework for teaching these skills is lacking. Collaborating with safety and science communication experts, an educational innovation was developed in a health and safety course for chemical engineering students. Students attended three science communication workshops and conducted a mock town hall based on briefs from historical chemical incidents. Initial and follow-up surveys show that students’ self-efficacy around these skills improved following participation in the educational innovation.
Applications of capillary action in drug delivery
(Cell Press, 2021) Li, Xiaosi; Zhao, Yue; Zhao, Chao; University of Alabama Tuscaloosa; Northwestern Polytechnical University
Contrary to the fact that capillary action is ubiquitous in our daily lives, its role in drug delivery has not attracted attention. Therefore, its application in medicine and disease treatment has not been actively developed. This perspective begins by reviewing the principles, advantages, and limitations of the three existing drug delivery strategies: non-covalent interaction, cavity loading, and covalent conjugation. Then, we discussed the principle of capillary action in drug delivery and the influencing factors that determine its performance. To illustrate the advantages of capillary action over existing drug delivery strategies and how the capillary action could potentially address the shortcomings of the existing drug delivery strategies, we described five examples of using capillary action to design drug delivery platforms for disease treatment: marker pen for topical and transdermal drug delivery, microneedle patch with a sponge container for pulsatile drug delivery, core- shell scaffold for sustained release of growth factors, oral bolus for insulin delivery to the esophagus, and semi-hollow floating ball for intravesical and gastroprotective drug delivery. Each of the five drug delivery platforms exhibits certain unique functions that existing drug delivery technologies cannot easily achieve, hence expected to solve specific practical medical problems that are not satisfactorily resolved. As people pay more attention to capillary action and develop more drug delivery platforms, more unique functions and characteristics of capillary action in drug delivery will be explored. Thus, capillary action could become an important choice for drug delivery systems to improve therapeutic drug efficacy, treat diseases, and improve human health.
Atomic Layer Deposition for Surface Modifications and Solid Film Fabrication
(University of Alabama Libraries, 2021) Yan, Haoming; Peng, Qing; University of Alabama Tuscaloosa
Along with the unceasing development of the surface and material science, modification of substrates surfaces in nanoscale, to fabricate the functional materials with precisely controlled dimensions, refined composition and desired properties becomes crucial. In this report, atomic layer deposition (ALD), a vapor phase, sequential and self-limiting deposition process, has been used as an alternative strategy to modify the surface of materials and fabricates nanometer or micrometer level of functional materials with precise control. In the first part of this dissertation, ALD was used to modify the surface of the shape-engineered nanocrystals (SENCs), which enhanced the thermal stability of the SENCs from 300˚C to 700˚C and enhanced the catalytic activities of the nanocrystals as well. We also proposed a new reaction mechanism of metal-organic precursor with oxide surface, in which the conventional layered ALD growth does not happen but the oxide surface was modified via controlled metal doping. In the second part of this dissertation, ALD precursors were used to reacting with liquid substrates to fabricate freestanding solid thin films. Benefits from the unique reaction mechanism of the ALD metal-organic precursors, the thickness and the compositions of the fabricated films can be controlled. The fundamental of gas-liquid reaction has been discussed in this study. In the third part of this dissertation, area-selective ALD (AS-ALD) has been reported using carboxylic acid self-assembled monolayer as a growth inhibitor. Excellent selectivity of AS-ALD has been achieved by using this method, which could potentially be used in microfabrication as a substitution step for photolithography.
Automatic food intake detection based on swallowing sounds
(Elsevier, 2012) Makeyev, Oleksandr; Lopez-Meyer, Paulo; Schuckers, Stephanie; Besio, Walter; Sazonov, Edward; University of Rhode Island; University of Alabama Tuscaloosa; Clarkson University
This paper presents a novel fully automatic food intake detectior methodology, an important step toward objective monitoring of ingestive behavior. The aim of such monitoring is to improve our understanding of eating behaviors associated with obesity and eating disorders. The proposed methodology consists of two stages. First, acoustic detection of swallowing instances based on mel-scale Fourier spectrum features and classification using support vector machines is performed. Principal component analysis and a smoothing algorithm are used to improve swallowing detection accuracy. Second, the frequency of swallowing is used as a predictor for detection of food intake episodes. The proposed methodology was tested on data collected from 12 subjects with various degrees of adiposity. Average accuracies of >80% and >75% were obtained for intra-subject and inter-subject models correspondingly with a temporal resolution of 30 s. Results obtained on 44.1 h of data with a total of 7305 swallows show that detection accuracies are comparable for obese and lean subjects. They also suggest feasibility of food intake detection based on swallowing sounds and potential of the proposed methodology for automatic monitoring of ingestive behavior. Based on a wearable non-invasive acoustic sensor the proposed methodology may potentially be used in free-living conditions. (C) 2012 Elsevier Ltd. All rights reserved.
Automatic identification of the number of food items in a meal using clustering techniques based on the monitoring of swallowing and chewing
(Elsevier, 2012) Lopez-Meyer, Paulo; Schuckers, Stephanie; Makeyev, Oleksandr; Fontana, Juan M.; Sazonov, Edward; University of Alabama Tuscaloosa; Clarkson University; University of Rhode Island
The number of distinct foods consumed in a meal is of significant clinical concern in the study of obesity and other eating disorders. This paper proposes the use of information contained in chewing and swallowing sequences for meal segmentation by food types. Data collected from experiments of 17 volunteers were analyzed using two different clustering techniques. First, an unsupervised clustering technique, Affinity Propagation (AP), was used to automatically identify the number of segments within a meal. Second, performance of the unsupervised AP method was compared to a supervised learning approach based on Agglomerative Hierarchical Clustering (AHC). While the AP method was able to obtain 90% accuracy in predicting the number of food items, the AHC achieved an accuracy >95%. Experimental results suggest that the proposed models of automatic meal segmentation may be utilized as part of an integral application for objective Monitoring of Ingestive Behavior in free living conditions. (C) 2011 Elsevier Ltd. All rights reserved.
Automatic Ingestion Monitor: A Novel Wearable Device for Monitoring of Ingestive Behavior
(IEEE, 2014) Fontana, Juan M.; Farooq, Muhammad; Sazonov, Edward; University of Alabama Tuscaloosa; Universidad Nacional Rio Cuarto
Objective monitoring of food intake and ingestive behavior in a free-living environment remains an open problem that has significant implications in study and treatment of obesity and eating disorders. In this paper, a novel wearable sensor system (automatic ingestion monitor, AIM) is presented for objective monitoring of ingestive behavior in free living. The proposed device integrates three sensor modalities that wirelessly interface to a smartphone: a jaw motion sensor, a hand gesture sensor, and an accelerometer. A novel sensor fusion and pattern recognition method was developed for subject-independent food intake recognition. The device and the methodology were validated with data collected from 12 subjects wearing AIM during the course of 24 h in which both the daily activities and the food intake of the subjects were not restricted in any way. Results showed that the system was able to detect food intake with an average accuracy of 89.8%, which suggests that AIM can potentially be used as an instrument to monitor ingestive behavior in free-living individuals.
Bacterial community shift in the coastal Gulf of Mexico salt-marsh sediment microcosm in vitro following exposure to the Mississippi Canyon Block 252 oil (MC252)
(Springer, 2015) Koo, Hyunmin; Mojib, Nazia; Huang, Jonathan P.; Donahoe, Rona J.; Bej, Asim K.; University of Alabama Birmingham; University of Alabama Tuscaloosa
In this study, we examined the responses by the indigenous bacterial communities in salt-marsh sediment microcosms in vitro following treatment with Mississippi Canyon Block 252 oil (MC252). Microcosms were constructed of sediment and seawater collected from Bayou La Batre located in coastal Alabama on the Gulf of Mexico. We used an amplicon pyrosequencing approach on microcosm sediment metagenome targeting the V3-V5 region of the 16S rRNA gene. Overall, we identified a shift in the bacterial community in three distinct groups. The first group was the early responders (orders Pseudomonadales and Oceanospirillales within class Gammaproteobacteria), which increased their relative abundance within 2 weeks and were maintained 3 weeks after oil treatment. The second group was identified as early, but transient responders (order Rhodobacterales within class Alphaproteobacteria; class Epsilonproteobacteria), which increased their population by 2 weeks, but returned to the basal level 3 weeks after oil treatment. The third group was the late responders (order Clostridiales within phylum Firmicutes; order Methylococcales within class Gammaproteobacteria; and phylum Tenericutes), which only increased 3 weeks after oil treatment. Furthermore, we identified oil-sensitive bacterial taxa (order Chromatiales within class Gammaproteobacteria; order Syntrophobacterales within class Deltaproteobacteria), which decreased in their population after 2 weeks of oil treatment. Detection of alkane (alkB), catechol (C2,3DO) and biphenyl (bph) biodegradation genes by PCR, particularly in oil-treated sediment metacommunity DNA, delineates proliferation of the hydrocarbon degrading bacterial community. Overall, the indigenous bacterial communities in our salt-marsh sediment in vitro microcosm study responded rapidly and shifted towards members of the taxonomic groups that are capable of surviving in an MC252 oil-contaminated environment.
Bioengineering of Heterogenous Glioblastoma Multiforme Microenvironment
(University of Alabama Libraries, 2021) Park, Seungjo; Kim, Yonghyun; University of Alabama Tuscaloosa
Glioblastoma (GBM) is the most aggressive brain tumor that originates from glioblastoma stem cells (GSCs). In the brain, GSCs are supported by a tumor microenvironment (TME) wherein the perivascular niche and hypoxic region are present. The glioblastoma microenvironment (GBME) exhibits high heterogeneity, vast cell-to-cell interactions, and stiff mechanical properties. To produce in vitro models mimicking the GBME features, GBM organoid (GBO) models have been developed. Conventional organoid studies rely on growing them in serum-free media, resulting in sphere formation. However, this conventional method is not scalable and often fails in recapitulating inter- and intratumor heterogeneity. Also, the conventional method is not ideal to produce adequate quantities of GBOs to screen drugs for personalized medicine. Therefore, development of a reproducible and scalable GBO culture method can provide a better platform to simulate novel treatments.First, the bioreactor design was optimized by using different diameters of impellers and bioreactor vessels. Even with similar shear stresses, cell proliferation was inhibited or promoted depending on the ratio of the impeller diameters to the vessel diameters. With the optimized vessel geometry, shear stress and media supplements were optimized for GBO production. The bioreactor GBOs (bGBOs) were produced in uniform size, not by clonal aggregations, but by cell proliferation. With the optimal agitation rate, bGBOs displayed upregulation of genes involved in stemness, hypoxia, angiogenesis, proliferation, and migration. The statistical analysis revealed the synergetic effects of the high agitation rate and the size of the bGBOs. Next, bGBO models were characterized by their morphologies and transcriptional and translational profiles. The bGBOs exhibited high and strong cell-to-cell contact. Multivariate gene analysis found a significant correlation between gene expression and the size of the bGBOs. GBME was established and spatially organized in bGBOs greater than 800 Âµm in diameter. Hypoxic TME was developed in bGBOs greater than 400 Âµm in diameter. Inside the bGBOs, spatially separated features of the hypoxic niche and the perivascular niche were demonstrated. Also, the large bGBOs displayed angiogenesis features. Self-established GBME was organized by transdifferentiated GBM into endothelial cells, pericytes, and astrocytes. GBME containing necrotic regions displayed more spatially distinctive and hierarchically organized GSC niches. The GSCs in the niche were regulated by transcription factors involved in dedifferentiation. Hydrogels have been employed to further understand underlying mechanisms of the transformation of GBM in the bGBO model. Mechanical properties of GBME was engineered using hyaluronic acid (HA)-based hydrogels. Cell behavior in response to the hydrogel stiffness was examined. Transcription factors dedifferentiating GBM into GSCs were translocated to the nucleus in response to stiffer substrates. Collectively, these studies provided a small-scale model for a high-throughput production of GBOs that recapitulate in vivo GBM features, including high heterogeneity and high cell-to-cell interactions. Hydrogel model and the bioreactor culture conditions described here suggest that GBOs can be biomanufactured by modulating mechanical stress.
Biomaterial Scaffolds as Pre-metastatic Niche Mimics Systemically Alter the Primary Tumor and Tumor Microenvironment
(Wiley, 2018) Aguado, Brian A.; Hartfield, Rachel M.; Bushnell, Grace G.; Decker, Joseph T.; Azarin, Samira M.; Nanavati, Dhaval; Schipma, Matthew J.; Rao, Shreyas S.; Oakes, Robert S.; Zhang, Yining; Jeruss, Jacqueline S.; Shea, Lonnie D.; Northwestern University; University of Michigan; University of Alabama Tuscaloosa
Primary tumor (PT) immune cells and pre-metastatic niche (PMN) sites are critical to metastasis. Recently, synthetic biomaterial scaffolds used as PMN mimics are shown to capture both immune and metastatic tumor cells. Herein, studies are performed to investigate whether the scaffold-mediated redirection of immune and tumor cells would alter the primary tumor microenvironment (TME). Transcriptomic analysis of PT cells from scaffold-implanted and mock-surgery mice identifies differentially regulated pathways relevant to invasion and metastasis progression. Transcriptomic differences are hypothesized to result from scaffold-mediated modulations of immune cell trafficking and phenotype in the TME. Culturing tumor cells with conditioned media generated from PT immune cells of scaffold-implanted mice decrease invasion in vitro more than two-fold relative to mock surgery controls and reduce activity of invasion-promoting transcription factors. Secretomic characterization of the conditioned media delineates interactions between immune cells in the TME and tumor cells, showing an increase in the pan-metastasis inhibitor decorin and a concomitant decrease in invasion-promoting chemokine (C-C motif) ligand 2 (CCL2) in scaffold-implanted mice. Flow cytometric and transcriptomic profiling of PT immune cells identify phenotypically distinct tumor-associated macrophages (TAMs) in scaffold-implanted mice, which may contribute to an invasion-suppressive TME. Taken together, this study demonstrates biomaterial scaffolds systemically influence metastatic progression through manipulation of the TME.
Carbon Capture Utilization and Storage in Methanol Production Using a Dry Reforming-Based Chemical Looping Technology
(American Chemical Society, 2022) Ugwu, Ambrose; Osman, Mogahid; Zaabout, Abdelghafour; Amini, Shahriar; Norwegian University of Science & Technology (NTNU); SINTEF; University of Alabama Tuscaloosa
This further investigates the concept of gas switching dry reforming (GSDR) that efficiently converts the two major greenhouse gases (CO2 and CH4) into a valuable product (syngas) for gas-to-liquid (GTL) syntheses. The proposed GSDR is based on chemical looping technology but avoids external circulation of solids (metal oxides) by alternating the supply of reducing and oxidizing gas into a single fluidized bed reactor to achieve redox cycles. Each cycle consists of three steps where a metal oxide/catalyst is first reduced using GTL offgases to produce CO2 (and steam) that is supplied to the next reforming step to produce syngas for GTL processes. The metal oxide is then reoxidized in the third step associated with heat generation (through the exothermic oxidation reaction of the metal oxide and air) to provide the heat needed for the endothermic dry methane reforming step. Experimental demonstrations have shown that a syngas H-2/CO molar ratio between 1 and 2 suitable for methanol production could be achieved. A further demonstration shows that pressure has negative effects on gas conversion. Following the successful experimental campaign, process simulations were completed using ASPEN to show how the GSDR process can be integrated into a methanol (MeOH) production plant.
Characterization of bismuth telluride two-dimensional nanosheets for thermoelectric applications
(University of Alabama Libraries, 2015) Guo, Lingling; Wang, Hung-Ta; University of Alabama Tuscaloosa
Solid-state thermoelectric devices are compact, scalable, quiet, and environmentally friendly, which are widely used as thermal engines or refrigerators. Bismuth telluride (Bi2Te3) and other V-VI group chalcogenides are known as one of the best thermoelectric materials specifically for applications in a temperature environment from room temperature to 300 ℃. Recently, the unique topological surface states were discovered in Bi2Te3 family materials, and these novel surface states are arisen from a strong spin-orbit coupling in topological insulators. Topological surface states are protected against time-reversal perturbations (i.e., non-magnetic impurities or surface defects), making the electronic transport essentially dissipation-less. Such unique transport behavior with zero energy loss provides new opportunities to enhance thermoelectric properties. Although the promise in thermoelectric properties of topological insulators have been shown in theoretical reports, there is a lack of experimental investigations for a better understanding of their basic properties. This research work focuses on the characterizations of fundamental properties of Bi2Te3 two-dimensional (2D) nanosheets. Samples were prepared via respective solvothermal synthesis and van der Waals epitaxy. The charged surface properties of Bi2Te3 2D nanosheets were investigated using kelvin probe force microscopy. The measured electrical potential difference between aminosilane self-assembled monolayer and Bi2Te3 nanosheet surfaces is found to be ∼650 mV, which is larger than that (∼400 mV) between the silicon oxide substrate and Bi2Te3 nanosheet surface. The elastic properties of Bi2Te3 2D nanosheets (i.e., Young’s modulus and prestress) were acquired by analyzing the thickness dependence of 2D nanosheet deformations creating by atomic force microscopy tips. The Young's modulus by fitting linear elastic behaviors of 26 samples is found only 11.7–25.7 GPa, significantly smaller than the bulk in-plane Young's modulus (50–55 GPa). Furthermore, the thermoelectric properties of Bi2Te3 2D nanosheets were characterized in the cryostat system at a temperature range of 20-400 K. The results reveal that electrical conductivity of 2D nanosheets decreases with increasing temperature and thickness, while the measured Seebeck coefficient does not show a strong thickness dependence and the value is smaller than bulk Bi2Te3. These fundamental properties would help improve the basic understanding of topological surface states towards practical applications.
Chemical vapor deposition of thin film materials for electronic and magnetic applications
(University of Alabama Libraries, 2011) Li, Ning; Klein, Tonya M.; University of Alabama Tuscaloosa
Chemical vapor deposition (CVD) has been employed to pursue high quality thin film growth for four different materials with excellent electronic or magnetic properties for certain device applications. The relationship between CVD processing conditions and various thin film properties has been systematically studied. Plasma enhanced atomic layer deposition (PEALD) is a special type of CVD technique and can be used for the deposition of very thin (few nanometers) and highly conformal thin films. PEALD of hafnium nitride (HfN) thin film is studied by using tetrakis (dimethylamido) hafnium (IV) (TDMAH) and hydrogen plasma. Prior to thin film deposition, TDMAH adsorption and reaction on hydrogenated Si(100) surface has been investigated by in-situ ATR-FTIR. It has been found that between 100˚C and 150˚C surface adsorbed TDMAH molecules start to decompose based on the ß-hydride elimination mechanism. The decomposition species on the surface has been found hard to desorb at 150˚C, which can contaminate the thin film if the purging/pumping time is insufficient. Uniform and moderately conductive HfNxCy films are deposited on hydrogen terminated Si(100) and thermally grown SiO2 (on Si) substrates by PEALD process. The dependence of thin film resistivity on plasma power is found to be related to the change of surface chemical composition. In vacuo XPS depth profile analysis showed the existence of hafnium carbide phase, which to a certain degree can improve the film conductivity. Direct liquid injection chemical vapor deposition (DLI-CVD) has been utilized for epitaxial growth of nickel ferrite (NiFe2O4), lithium ferrite (LiFe5O8) and barium titanate (BaTiO3) films on various lattice match substrates. For the deposition of nickel ferrite, anhydrous Ni(acac)2 and Fe(acac)3 (acac = acetylacetonate) are used as precursor sources dissolved in N,N-dimethyl formamide (DMF) for the DLI vaporizer system. Epitaxial nickel ferrite films of stoichiometric composition are obtained in the temperature range of 500-800 ºC on both MgO(100) and MgAl2O4(100). Film morphology is found to be dependent on the deposition temperature with atomically smooth films being obtained for deposition temperature of 600 and 700 ºC. Magnetic measurements reveal an increase in the saturation magnetization for the films with increasing growth temperature, which correlates well with the trend for improved epitaxial growth. Nickel ferrite films deposited on MgAl2O4 (100) at 800ºC exhibit saturation magnetization very close to the bulk value of 300 emu/cm3. Out-of-plane FMR measurement shows the narrowest FMR line width of ~160 Oe for films deposited at 600˚C. For lithium ferrite deposition, anhydrous Li(acac) and Fe(acac)3 are dissolved in DMF in a molar ratio of 1:5. Epitaxial growth of lithium ferrite films on MgO(100) are observed in the temperature range of 500˚C to 800˚C. The as grown films show increasing saturation magnetization with increasing deposition temperature due to the improved degree of crystal texture. For barium titanate thin film deposition, Ba(hfa)2*tetraglyme and Ti(thd)2(OPri)2 are dissolved in toluene in a molar ratio of 1:1. Epitaxial growth of barium titanate on MgO(100) has been found at the temperature of 750˚C. Film with a thickness of ~500 nm has a relatively large roughness of ~20 nm. Small amount of F elements, which exists in Ba-F bonds, has been detected in the thin film by XPS.
The chloroplast genomes of Bryopsis plumosa and Tydemania expeditiones (Bryopsidales, Chlorophyta): compact genomes and genes of bacterial origin
(BMC, 2015) Leliaert, Frederik; Lopez-Bautista, Juan M.; University of Alabama Tuscaloosa; Ghent University
Background: Species of Bryopsidales form ecologically important components of seaweed communities worldwide. These siphonous macroalgae are composed of a single giant tubular cell containing millions of nuclei and chloroplasts, and harbor diverse bacterial communities. Little is known about the diversity of chloroplast genomes (cpDNAs) in this group, and about the possible consequences of intracellular bacteria on genome composition of the host. We present the complete cpDNAs of Bryopsis plumosa and Tydemania expeditiones, as well as a re-annotated cpDNA of B. hypnoides, which was shown to contain a higher number of genes than originally published. Chloroplast genomic data were also used to evaluate phylogenetic hypotheses in the Chlorophyta, such as monophyly of the Ulvophyceae (the class in which the order Bryopsidales is currently classified). Results: Both DNAs are circular and lack a large inverted repeat. The cpDNA of B. plumosa is 106,859 bp long and contains 115 unique genes. A 13 kb region was identified with several freestanding open reading frames (ORFs) of putative bacterial origin, including a large ORF (>8 kb) closely related to bacterial rhs-family genes. The cpDNA of T. expeditiones is 105,200 bp long and contains 125 unique genes. As in B. plumosa, several regions were identified with ORFs of possible bacterial origin, including genes involved in mobile functions (transposases, integrases, phage/plasmid DNA primases), and ORFs showing close similarity with bacterial DNA methyltransferases. The cpDNA of B. hypnoides differs from that of B. plumosa mainly in the presence of long intergenic spacers, and a large tRNA region. Chloroplast phylogenomic analyses were largely inconclusive with respect to monophyly of the Ulvophyceae, and the relationship of the Bryopsidales within the Chlorophyta. Conclusions: The cpDNAs of B. plumosa and T. expeditiones are amongst the smallest and most gene dense chloroplast genomes in the core Chlorophyta. The presence of bacterial genes, including genes typically found in mobile elements, suggest that these have been acquired through horizontal gene transfer, which may have been facilitated by the occurrence of obligate intracellular bacteria in these siphonous algae.
Chromium(III) Interaction with Transferrin and Transferrin Receptor
(University of Alabama Libraries, 2021) Edwards, Kyle Carter; Vincent, John B.; University of Alabama Tuscaloosa
Transferrin (Tf), the major iron transport protein in the blood, apparently also transports trivalent chromium via endocytosis. The release of chromium(III) from human serum transferrin has been examined under conditions mimicking an endosome during endocytosis. At pH 4.5 and 5.5, the release of Cr(III) from Tf occurs rapidly from the C-lobe binding site and slowly from the N-lobe binding site. The loss of N-lobe bound Cr(III) under these conditions is accelerated by the presence of a anionic chelating ligand. When Cr(III)-loaded transferrin is added to soluble transferrin receptor (sTfR), the loss of Cr(III) from both binding sites becomes rapid at acidic pH, more rapid than from either site in the absence of the receptor. Loss of Cr(III) from the Tf-sTfR complex is easily sufficiently rapid for Tf to serve as the physiological transporter of Cr(III) from the bloodstream to the tissues. Studies have also found that Cr(III)2-Tf can exist in multiple conformations giving rise to different spectroscopic properties and different rates of Cr(III) release. Time-dependent spectroscopic studies of the binding and release of Cr(III) from human serum Tf have been used to identify three conformations of Cr(III)2-Tf. The conformation formed between 5 and 60 minutes after the addition of Cr(III) to apoTf at pH 7.4 resembles the conformation of Cr(III)2-Tf in its complex with sTfR and loses Cr(III) rapidly at endosomal pH. Loss of Cr(III) from Cr2-Tf and Cr2-Tf-sTfR in the presence of apo-chromodulin (LMWCr) results in accumulation of Cr(III) bound to LMWCr and is rapid when sTfR is present indicating the species can form under endosomal conditions and may be the next carrier in the Cr(III) transport pathway. Techniques used throughout the projects were also applied to Mn(III)2-Tf, and the first parallel mode EPR signal for Mn(III)-Tf is reported, which could prove valuable for future studies.
A CNN-LSTM neural network for recognition of puffing in smoking episodes using wearable sensors
(Springer Nature, 2020) Senyurek, Volkan Y.; Imtiaz, Masudul H.; Belsare, Prajakta; Tiffany, Stephen; Sazonov, Edward; University of Alabama Tuscaloosa; State University of New York (SUNY) Buffalo
A detailed assessment of smoking behavior under free-living conditions is a key challenge for health behavior research. A number of methods using wearable sensors and puff topography devices have been developed for smoking and individual puff detection. In this paper, we propose a novel algorithm for automatic detection of puffs in smoking episodes by using a combination of Respiratory Inductance Plethysmography and Inertial Measurement Unit sensors. The detection of puffs was performed by using a deep network containing convolutional and recurrent neural networks. Convolutional neural networks (CNN) were utilized to automate feature learning from raw sensor streams. Long Short Term Memory (LSTM) network layers were utilized to obtain the temporal dynamics of sensor signals and classify sequence of time segmented sensor streams. An evaluation was performed by using a large, challenging dataset containing 467 smoking events from 40 participants under free-living conditions. The proposed approach achieved an F1-score of 78% in leave-one-subject-out cross-validation. The results suggest that CNN-LSTM based neural network architecture sufficiently detect puffing episodes in free-living condition. The proposed model be used as a detection tool for smoking cessation programs and scientific research.
Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae
(BMC, 2021) Steele, Erika; Alebous, Hana D.; Vickers, Macy; Harris, Mary E.; Johnson, Margaret D.; University of Alabama Tuscaloosa; University of Jordan
BackgroundMyo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellular environments. A physiological role for secreted MIP has remained elusive since its first detection in intercellular space. To provide further insight into the role of MIP in intercellular milieus, we tested the hypothesis that MIP may function as a growth factor, synthesizing inositol phosphate in intercellular locations requiring, but lacking ability to produce or transport adequate quantities of the cell-cell communicator. This idea was experimentally challenged, utilizing a Saccharomyces cerevisiae inositol auxotroph with no MIP enzyme, permeable membranes with a 0.4 mu m pore size, and cellular supernatants as external sources of inositol isolated from S. cerevisiae cells containing either wild-type enzyme (Wt-MIP), no MIP enzyme, auxotroph (Aux), or a green fluorescent protein (GFP) tagged reporter enzyme (MIP- GFP) in co- culturing experiments.ResultsResulting cell densities and microscopic studies with corroborating biochemical and molecular analyses, documented sustained growth of Aux cells in cellular supernatant, concomitant with the uptakeof MIP, detected as MIP-GFP reporter enzyme. These findings revealed previously unknown functions, suggesting that the enzyme can: (1) move into and out of intercellular space, (2) traverse cell walls, and (3) act as a growth factor to promote cellular proliferation of an inositol requiring cell.ConclusionsCo-culturing experiments, designed to test a probable function for MIP secreted in extracellular vesicles, uncovered previously unknown functions for the enzyme and advanced current knowledge concerning spatial control of inositol phosphate biosynthesis. Most importantly, resulting data identified an extracellular vesicle (a non-viral vector) that is capable of synthesizing and transporting inositol phosphate, a biological activity that can be used to enhance specificity of current inositol phosphate therapeutics.
Combined Syngas and Hydrogen Production using Gas Switching Technology
(American Chemical Society, 2021) Ugwu, Ambrose; Zaabout, Abdelghafour; Donat, Felix; van Diest, Geert; Albertsen, Knuth; Muller, Christoph; Amini, Shahriar; SINTEF; Swiss Federal Institutes of Technology Domain; ETH Zurich; University of Alabama Tuscaloosa; Norwegian University of Science & Technology (NTNU)
This paper focuses on the experimental demonstration of a threestage GST (gas switching technology) process (fuel, steam/CO2, and air stages) for syngas production from methane in the fuel stage and H-2/CO production in the steam/ CO2 stage using a lanthanum- based oxygen carrier (La0.85Sr0.15Fe0.95Al0.05O3). Experiments were performed at temperatures between 750-950 degrees C and pressures up to 5 bar. The results show that the oxygen carrier exhibits high selectivity to oxidizing methane to syngas at the fuel stage with improved process performance with increasing temperature although carbon deposition could not be avoided. Co-feeding CO2 with CH4 at the fuel stage reduced carbon deposition significantly, thus reducing the syngas H-2/CO molar ratio from 3.75 to 1 (at CO2/CH4 ratio of 1 at 950 degrees C and 1 bar). The reduced carbon deposition has maximized the purity of the H-2 produced in the consecutive steam stage thus increasing the process attractiveness for the combined production of syngas and pure hydrogen. Interestingly, the cofeeding of CO2 with CH4 at the fuel stage showed a stable syngas production over 12 hours continuously and maintained the H-2/CO ratio at almost unity, suggesting that the oxygen carrier was exposed to simultaneous partial oxidation of CH4 with the lattice oxygen which was restored instantly by the incoming CO2. Furthermore, the addition of steam to the fuel stage could tune up the H-2/CO ratio beyond 3 without carbon deposition at H2O/ CH4 ratio of 1 at 950 degrees C and 1 bar; making the syngas from gas switching partial oxidation suitable for different downstream processes, for example, gas-to-liquid processes. The process was also demonstrated at higher pressures with over 70% fuel conversion achieved at 5 bar and 950 degrees C.

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