Multinuclear Solid-State NMR Investigation of Structure, Dynamics, and Formation of Porous Materials

The work described herein demonstrates the utility of solid-state nuclear magnetic resonance (SSNMR) spectroscopy for the characterization of molecular-level structure and dynamics in porous materials, including the determination of the reaction pathways involved in the formation of porous solids made via solid-state synthetic techniques, a study of the motion of dynamic components of metal-organic frameworks (MOFs) that are prototypes for future molecular machines, and the structural characterization of a surface-supported catalyst. In Chapters 2 and 3, accelerated aging and mechanochemical reactions are used to synthesize cadmium-containing zeolitic imidazolate frameworks (ZIFs). These techniques provide a means for clean and efficient syntheses of these materials; however, little is known about the reaction kinetics and mechanisms underlying their production. First, the structure of a new cadmium-imidazolate framework (CdIF) is determined using a combination of powder X-ray diffraction (PXRD) and SSNMR, a methodology known as NMR-assisted crystallography. SSNMR experiments are also used to monitor the formation of ZIFs made using mechanochemical synthesis, providing information on the intermediates and products of the reactions. It is revealed that the initial mechanochemical ball milling provides the activation energy for the formation of ZIFs, but aging reactions within the milling jars drive the reaction to completion. As demonstrated here, milling times as short as five seconds provide enough energy for the initiation of the reactions, allowing for extremely low-energy synthesis of these materials. In Chapter 4, series of metal-organic frameworks (MOFs) with dynamic, interlocked crown ether rings are investigated to determine the factors that influence the motion of the rings. It is demonstrated that the size of the rings and the framework structure affect the motion. 13C variable temperature SSNMR is used to confirm the shuttling motion of rings between recognition sites on an axle that is incorporated into a MOF. Next, a study on a series of simple inorganic molecular rotors is described. It is shown that some of these compounds act as rotors with very low energy barriers that exhibit random rotational dynamics at temperatures below 75 K, while other structurally similar compounds do not display any motions over a wide range of temperatures. It is posited that steric and electronic effects from the coordinating ligands are responsible for the observed dynamics. 2H SSNMR is shown to be essential for classifying and understanding the dynamics of these low-energy molecular rotors Finally, 35Cl SSNMR is used to elucidate the structure of a transition-metal compound bound to the surface of a porous silica material. It is demonstrated that ultra-wideline (UW) 35Cl SSNMR spectra for transition-metal complexes can be rapidly acquired using a combination of high magnetic fields and specialized pulse sequences. These spectra allow for the differentiation of different Cl bonding environments (i.e., bridging, terminal axial, and terminal equatorial). Density functional theory (DFT) calculations and an accompany molecular-orbital analysis allow for an understanding of the origin of the observed 35Cl electric field gradient (EFG) parameters, which influence the 35Cl quadrupolar interactions. The structure of a surface-supported complex is then proposed, demonstrating the applicability of these techniques to the study of very dilute catalytic species

Economic Integration as a Means for Promoting Regional Political Stability: Lessons from the European Union and MERCOSUR

The Article explores ways to ensure the future economic viability and the territorial integrity of Kosovo, whether as an independent state or as an entity with autonomous powers under the sovereignty of Serbia. The Article discusses the experiences of the European Union and MERCOSUR economic integration projects that have led to permanent peaceful relations among the participating countries, and contributed to overcoming historically bitter rivalries and conflicts. In examining the EU experience, the Article explores how supranational institutions coupled with the concept of subsidiarity have heightened regional autonomy within existing national states and made demands for secession both redundant and obsolete. The Article focuses on lessons that can be gleaned from the EU and MERCOSUR in terms of any effort to integrate the Balkan countries, including the possible establishment of a political union. The Article also posits how an economically integrated Balkans facilitates accession by all the participating states into the EU by providing solutions to at least some of the problems that, if not redressed, will impede their membership indefinitely

Compositional Characterization of Different Industrial White and Red Grape Pomaces in Virginia and the Potential Valorization of the Major Components

To better evaluate potential uses for grape pomace (GP) waste, a comprehensive chemical composition analysis of GP in Virginia was conducted. Eight commercial white and red pomace samples (cv. Viognier, Vidal Blanc, Niagara, Petit Manseng, Petit Verdot, Merlot, Cabernet Franc, and Chambourcin) obtained from different wineries in Virginia, USA were used. For extractives, GPs contained 2.89%–4.66% titratable acids, 4.32%–6.60% ash, 4.62%–12.5% lipids with linoleic acid being the predominant (59.0%–70.9%) fatty acid, 10.4–64.8 g total phenolic content (gallic acid equivalents)/kg GP, 2.09–53.3 g glucose/kg GP, 3.79–52.9 g fructose/kg GP, and trace sucrose. As for non-extractives, GPs contained 25.2%–44.5% lignin, 8.04%–12.7% glucan, 4.42%–7.05% xylan, and trace amounts of galactan, arabinan, and mannan (less than 3% in total). Potential usages of these components were further examined to provide information on better valorization of GP. Considering the valuable extractives (e.g., polyphenols and oil) and non-extractives (e.g., lignin), designing a biorefinery process aiming at fully recover and/or utilize these components is of future significance

High Fat Diet Induced Obesity Impairs Skeletal Muscle Glycogen and Lipid Preservation After Adiponectin Incubation

High fat diets have been attributed as critical factors contributing to obesity and type 2 diabetes, characterized by increased lipid accumulation, impaired glucose uptake, and defects in glycogen storage in skeletal muscle. Adiponectin, an adipokine, has been shown to have antidiabetic effects by improving fat oxidation and glucose uptake. PURPOSE: To investigate the effects of adiponectin incubation, in high fat diet induced obese rats, on measures of skeletal muscle substrate metabolism including glycogen, glucose transporter 4 (GLUT4), lipid, and mitochondrial contents. METHODS: Male Sprague Dawley rats were fed a Western-style (21% fat by weight; 41% total energy) high fat diet for 9 weeks to induce obesity, then, for 6 weeks, either continued the Western Diet (WD) or were fed a standard Chow Diet (WCD) (4.8% fat; 0.74% saturated; 2% mono; 1.77% poly); a control group followed a 15-week chow diet (CD). Following the 15-week diet intervention, right and left hind-leg extensor digitorum longus (EDL) muscles were incubated in an organ bath (Krebs-Henseleit buffer containing 2000 mg/L glucose) with or without 0.1 mg/ml adiponectin for 30 minutes. Glycogen content was measured with periodic acid-schiff staining, GLUT4 (ab654), lipid (bodipy), and mitochondrial (ab14744) contents were measured using immunohistochemical techniques and quantified with imageJ software. RESULTS: There were no changes in substrate concentrations with adiponectin incubation in any diet group. However, the change (D) in glycogen, with adiponectin, was greater in animals fed a control chow diet compared to animals that followed a 15-week high fat Western-style diet (WD) (change (D); CD: 0.11±0.07 vs. WD: -0.25±0.14; one-way ANOVA p=0.048). When change in lipid content, after adiponectin treatment, was compared, animals fed high fat diets showed impaired preservation of lipid compared to the control group (change (D); CD: 25.9±11.2 vs. WD: -21.1±14.8 p=0.02; CD: 25.9±11.2 vs. WCD: -18.8±7.7 p=0.02). CONCLUSION: 9 weeks of a high fat Western-style diet is sufficient to induce defects in skeletal muscle substrate concentrations, including glycogen and lipid contents. Although adiponectin incubation did not increase substrate concentrations, a control chow diet demonstrated a better ability to preserve glycogen and lipid contents compared to high fat diet induced obese rats. Despite reverting to a standard chow diet, high fat diet induced obese rats did not demonstrate an insulin-sensitizing response from adiponectin incubation

High Fat Diet Rich in Saturated Fatty Acids, but Not Monounsaturated Fatty Acids, Impairs Glycogen Preservation after Adiponectin Treatment

High fat diet (HFD) is associated with the progression of obesity, type 2 diabetes and diminished insulin sensitivity, which is characterized by a lower glucose uptake and glycogen synthesis capacity in skeletal muscle. Adiponectin (Ad), on the other hand, is a cytokine secreted by adipose tissue that promotes glucose uptake and fatty acid oxidation in skeletal muscle. PURPOSE: To determine the effects of Ad on skeletal muscle glycogen, GLUT 4, mitochondrial and lipid content in animals fed with a HFD but with alterations in dietary fatty acids (mixed fat western diet and predominately monounsaturated fatty acid). METHODS: Male Sprague Dawley rats were fed a Western-style (21% fat) HFD for 9 weeks to induce obesity, then, for 6 weeks, continued the mixed fat Western diet (WD) (9.8% saturated fat; 7.7% mono; 3.5% poly; n=8) or a HFD high in monounsaturated fatty acids (MUFA) (21% fat; 17.76% mono; 1.8% poly; n=8). A control group followed a 15-week standard Chow diet (CD) (4.8% fat; 0.74% saturated fat; 2% mono; 1.77% poly; n=9). Right and left hind-leg extensor digitorum longus (EDL) muscles were incubated in an organ bath (containing Krebs-Henseleit buffer with 2000 mg/L glucose, without calcium chloride and sodium bicarbonate) with or without 0.1 mg/ml Ad for 30 minutes. Glycogen content in the EDL muscle was measured by using periodic acid-schiff staining, while GLUT 4 protein content was measured using rabbit polyclonal antibody against GLUT 4 (ab654), mitochondrial content was measured using a mouse polyclonal antibody against COX 4 protein (ab14744) and lipid content was measured using BODIPY 493/503, using immunohistochemistry techniques. Images were quantified with ImageJ software. RESULTS: The Ad incubation resulted in a decrease in muscle glycogen content in animas fed with WD (4.85 ± 0.13 to 4.29 ± 0.11 AU; p=0.05). This decrease in glycogen content in the WD group was significantly different compared to a better preservation of glycogen in both CD (p=0.04) and the MUFA diet groups (p=0.012) (CD: 0.11 ± 0.071 AU; WD: -0.25 ± 0.14 AU; MUFA: 0.18 ± 0.05 AU; one way ANOVA, p=0.01). Animals fed with CD tended to have a better preservation of lipid content compared to animals fed with WD (p=0.07) and a diet high in MUFA (p=0.09) (CD: 25.93 ± 11.2 AU; WD: -21.09 ± 14.81 AU; MUFA: 25.97 ± 16.17 AU; one way ANOVA, p=0.06). There were no significant changes in GLUT 4 and mitochondrial content regardless of diet and adiponectin incubation. CONCLUSIONS: Animals fed with a western style HFD rich in saturated fat show an impaired response to adiponectin induced increase/preservation of glycogen in skeletal muscle compared to a chow diet, as well as a HFD rich in MUFA. Diets high in saturated fatty acids may have an impaired response to adiponectin treatment

Lower Skeletal Muscle Mitochondrial Content After a High Fat Diet Rich in Polyunsaturated Fatty Acids Compared to a High Fat Diet Rich in Monounsaturated Fatty Acids

High fat diet (HFD) has been associated with weight gain, insulin resistance, and type 2 diabetes. The composition of fatty acids in various diets (monounsaturated, polyunsaturated, saturated) influence levels of blood insulin, glucose, and the onset of metabolic and cardiovascular diseases. PURPOSE: Determine the effects of high fat diets with alterations in the major dietary fatty acid content (a mixed fat western diet, a polyunsaturated fatty acid diet or a monounsaturated fatty acid diet) on skeletal muscle glycogen, lipid, glucose transporter 4 (GLUT4), and mitochondrial content. METHODS: Male Sprague Dawley rats were fed a 21% (by weight; 41% total energy) high fat western-style diet for 9 weeks to induce obesity. They were then divided into 3 dietary groups that continued on a HFD for the next 6 weeks of 1) mixed fat western diet (WD) (9.8% saturated, 7.7% mono; 3.5% poly; n=9); 2) monounsaturated fat (MUFA) (2.8% saturated, 15.8% mono; 2.2% poly; n=9); or 3) polyunsaturated fat (PUFA) (3.0% saturated; 2.9%mono; 15.7% poly; n=8). A control group followed a 15-week low fat Chow diet (CD) (4.8% fat; 0.74% saturated fat; 2% mono; 1.77% poly; n=9). At the end of the dietary intervention, glycogen content was measured in extensor digitorum longus (EDL) with periodic acid-schiff staining. GLUT4 protein content was measured using rabbit polyclonal antibody against GLUT4 (ab654), mitochondrial content was measured using mouse polyclonal antibody against COX4 protein (ab14744), and lipid content was measured using BODIPY 493/503, using immunohistochemistry techniques. Images were captured by ZEN imaging software by ZEIS and data was analyzed with ImageJ. RESULTS: There were no significant differences in glycogen content after 6 weeks of HFD with different dietary fatty acid composition, compared to control chow diet. (AU± SEM; CD: 4.41±0.04, WD: 4.74± 0.13, MUFA: 4.54± 0.08, PUFA: 4.54± 0.11, one-way ANOVA p= 0.11). There were also no significant differences in GLUT4 protein content (AU± SEM; CD: 74.68± 5.91, WD: 64.42 ± 2.88, MUFA: 76.12± 6.51, PUFA: 62.83± 4.12; one-way ANOVA p= 0.17) and lipid content after a HFD differing in dietary fatty acids compared to a control chow diet. (AU± SEM; CD: 168± 19.28, WD: 141.3 ± 15.5, MUFA: 193.7 ± 15.3, PUFA: 152.1± 16,69; one-way ANOVA p=0.18). Mitochondria content was less in HFD rich in PUFA when compared to HFD rich in MUFA (CD; WD; AU± SEM; MUFA 60.33±7.31 vs. PUFA 37.42±5.53; MUFA vs. PUFA p= 0.03). CONCLUSION: Our data suggest that six weeks of high fat diet does not affect skeletal muscle glycogen content, lipid content and GLUT4 content regardless of dietary fatty acid composition. Six weeks of high fat diet rich in polyunsaturated fatty acids results in lower mitochondrial content compared to high fat diet rich in monounsaturated fatty acid. Our data suggest that high fat diet rich in polyunsaturated fatty acids may negatively impact skeletal muscle oxidative capacity compared to a diet rich in monounsaturated fatty acids