A Review of Biochemical Processes and Techniques for Soil Stabilization and Resilience

Biochemical, chemical, and mechanical, techniques have been employed to enhance soil resilience for decades. While the use of mechanical techniques requires transporting huge amounts of soil materials, the cement used in chemical techniques may lead to increase atmospheric carbon dioxide. Numerous studies indicate that biochemical techniques may be less expensive, cost effective, and environmentally friendly. Biopolymers and enzymes derived from microorganisms have been suggested as biological enhancers in strengthening and fortifying soils used for earthen structures. Lime and other treatment techniques used as biobased materials have been shown to be less effective for stabilizing soils. Here, we review biochemical processes and techniques involved in the interactions of soil enzymes, microorganisms, microbial extracellular polymeric substances, and other biopolymers with soil particles, and the challenges and strategies of their use as biobased materials for stabilizing soils. This review provides their impacts on various soil properties and the growth potentials of agricultural crops. .

Evaluation of Rhizobium tropici-Derived Extracellular Polymeric Substances on Selected Soil Properties, Seed Germination, and Growth of Black-Eyed Peas (Vigna unguiculata)

Rhizobium tropici-derived extracellular polymeric substances (EPS) have been used in soils to enhance soil structures and mitigate soil erosions. However, information on their use to improve soil health and fertility indicators, and plant growth is limited. In a greenhouse study, we investigated their effects on some soil health, soil fertility indices, and the growth of black-eyed peas (Vigna unguiculate). Results showed that soils incubated with EPS significantly increased basal soil respiration, soil microbial biomass, permanganate oxidizable carbon (POC), and potentially mineralizable nitrogen (PMN). The EPS shifted microbial populations from bacteria to fungi and Gram (−ve) to Gram ( ve) bacteria. However, it had little or no effects on soil pH, soil organic matter (SOM), and cation exchange capacity (CEC). The EPS decreased soil moisture loss, increased soil aggregate stability, but delayed blacked-eyed peas germinations in the soils. At 0.1% (w/w) concentrations in soils, there was increase in plant root nodulations and vegetative growth. This study was carried out within 40 days of incubating soils with EPS or growing the black-eyed peas in a greenhouse study. The plant growth parameters were taken before flowering and fruiting. Further studies of the effects of incubating soils with the extracellular polymeric substances on plant growth. Soil microbial biomass, microbial diversities, and other soil fertility indices are deemed necessary.

Quantum Unruh Effect on Radiation of Black Holes

The quantum Unruh effect on radiation of a gravitational object including a black hole is analyzed and calculated. It is surprisingly found that the well-known Hawking radiation of a black hole is not physical. Applying the Stephan-Boltzmann law with the use of the Unruh radiation temperature at the surface of a black hole to calculate the power of radiation of the black hole is conceptually unphysical. This is because the Unruh radiation temperature results from the gravitational field of the object rather than from the thermal motion of matter of the object, so that the Stephan-Boltzmann law is not applicable. This paper shows that the emission power of Unruh radiation from a gravitational object should be calculated in terms of the rate of increase of the total Unruh radiation energy outside the object. The result obtained from this study indicates that a gravitational object can emit Unruh radiation when the variation of its mass and radius satisfies an inequality of dM/M > 1.25dR/R. For a black hole, the emission of Unruh radiation does not occur unless it can loose its mass (dM < 0). The emission power of Unruh radiation is only an extremely tiny part of the rate of mass-energy loss if the black hole is not extremely micro-sized. This study turns down our traditional understanding of the Hawking radiation and thermodynamics of black holes.

Vibrational Spectroscopy of Pain Relievers: Traditional and Remote Raman Techniques

The application of vibrational spectroscopy in the pharmaceutical industry is widely investigated, from the quality assurance of the product during the production process control to the final products’ quality control and the authentication of products on the markets. This study focuses on non-contact and noninvasive detection and identification of pain-relievers at 1-5 meters standoff distances. The specimens analyzed include standard laboratory-grade active ingredients and commercially available pain relievers in powder, solid and liquid forms. All the remote measurements captured revealed the Raman signatures of the specimens, with varying peak intensities. To correlate the band intensities captured with the standoff distances between the laser source and the specimens, the intensity ratios of the two prominent peaks of the laboratory grade reference active ingredient (1607 and 1319 cm-1) normalized with 1319 cm-1 are used. The results of the study suggest the viability of standoff Raman spectroscopy for routine monitoring and identification of pharma-ceuticals, including counterfeit pain relievers.

Future Land-Use Land-Cover Scenarios for the Flint River Watershed in Northern Alabama Using the Prescott Spatial Growth Model

A changing mosaic of natural vegetation and human land uses has evolved within and around the Flint River Watershed (FRW) in Alabama and Tennessee over the past several decades. To determine the cause of change and linkage between human activities and environmental change can prove problematic. Subsequently, there is a need to produce projections of future environments based on planning instruments and socio-economic parameters. Scenarios of potential future land use land cover (LULC) change are required in order to better manage potential impacts on many environmental issues. This study creates future scenarios for the year 2030 from baseline land use of 2001, relative to three projected land use scenarios which include differences related to conservation, planning, and development. The future growth scenarios were created using the ArcGIS tool, Prescott Spatial Growth Model (PSGM). The model allows users to build different future growth scenarios based on socio-economic projections such as population, employment and other controlling factors. The simulation results indicate that LULC changes associated with future urbanization can increase by ~23% - 43% within the FRW, which will lead to significant environmental issues if not managed properly. The overall analysis and model results demonstrate the ability of future growth scenarios to explore and evaluate options for a future environment. Spatial modeling and analysis tools, such as PSGM, provide a powerful approach to evaluate potential impacts of LULC change in the future and should be used to manage urbanization in areas with more intense development.

Microbial Compositions and Enzymes of a Forest Ecosystem in Alabama: Initial Response to Thinning and Burning Management Selections

Prescribed burning and tree thinning are commonly used restoration practices for US forests management to increase forest productivity and enhance plant and animal diversity. The impact of these practices in Alabama’s Bankhead National Forest (BNF) to soil microbial components and overall forest soil health are unknown. We hypothesized that microbial assemblages and enzyme activities are continuously changing in forest ecosystems especially due to management selections. Therefore, the objective of this study was to assess changes in microbial community compositions (fungal vs bacterial populations) via fatty acid methyl ester (FAME) profiling and several enzyme activities (β-glucosaminidase, acid phosphatase, arylsulfatase, β-glucosidase, xylanase, laccase, and manganese peroxidase) critical to soil organic matter (SOM) dynamics and biogeochemical cycling. In this forest, heavily-thinned plots without burning or less frequent burning treatments seemed to provide more favorable conditions (higher pH and lower C:N ratios) for C and N mineralization. This may explain a slight increase (by 12%) detected in fungi:bacteria (F:B) ratio in the heavily-thinned plots relative to the control. Thinned (lightly and heavily) plots showed greater ligninolytic (laccase and MnP) activities and lower β-glucosidase and β-glucosaminidase activities compared to the no-thinned plots probably due to increase depositions of woody recalcitrant C materials. We observed significant but negative correlations between the ligninolytic laccase and manganese peroxidase (Lac and MnP) enzymes respectively, with MBC (?0.45* and ?0.68** respectively) and MBN (?0.43* and ?0.65** respectively). Prescribed burning treatment reduced microbial biomass C and N of the 9-yr burned plot/lightly thinned plotsprobably due to depletion of labile C sources with the high temperatures, leaving mostly recalcitrant C sources as available soil substrates. Gram-positive bacteria (i15:0, a15:0, i17:0, and a17:0), actinomycetes (10-Me17:0, 10-Me18:0), AMF (16:1ω5c), and saprophytic fungi (18:1ω9c), largely contributed to the microbial compositions. This study bridges knowledge gaps in our understanding of microbial community compositions and enzyme-mediated processes in repeatedly burned and thinned forest ecosystems.

Consumer Knowledge about Electric Buses in Underserved Communities in Huntsville, Alabama

The major offshoot of innovation of electric vehicles (EVs) is sustainability. Given the prevailing challenges of carbon emissions from automobiles and the consequent effects on climate change, the introduction of EVs is timely to serve as an effective mechanism for reversing global warming. However, knowledge of EVs is not well distributed among the general population. This study is therefore aimed to analyze the familiarity of Americans with the basic features of EVs. One hundred respondents were selected from two underserved communities in Huntsville, Alabama, using a simple sampling technique. Nonetheless, only 71 residents returned the filled questionnaires. Data were analyzed using frequency counts and descriptive statistics. Findings revealed that the respondents were generally aware of EVs, but EVs are not yet common on their roads. The respondents also signaled low preferences for EVs. The purchase price, charging stations, and limited supply are the candid explanations for why EVs are not a priority in the respondents’ choice of cars. To bolster peoples’ taste toward EVs, the study, therefore, concludes that government authorities and city planners should popularize incentives among the people in underserved communities.

Chemopreventive Potential of Probiotics and Prebiotics

Utilization of probiotics and prebiotics in food products and in the diet supplemental form continues to gain interest because of their health benefits. Cancer is the leading cause of death and strategies for chemoprevention are important to reduce mortality and morbidity. Probiotics are gaining attention to use as preventive agents. Efficacy of their use as chemopreventive agents was established through research. This review focused on the mechanisms of prebiotics and probiotics action against cancer. Benefits of probiotics against cancer are attributed to competitive exclusion of pathogenic bacteria, direct physical binding to carcinogens, altering intestinal environment to modulate the production enzymes, antioxidant activity and immune modulation. Prebiotics are indigestible food components that could promote the growth of probiotics. Chemopreventive properties of prebiotics are due to their production of short chain fatty acids and enhancing the immunity of the host. Anticarcinogenic properties of pre- and probiotics result from a combination of events rather from a single event.

Phytochemical Content, Radical Scavenging Ability &Enzyme Inhibiting Activities of Selected Spices (Cinnamon, Cardamom and Cloves)

Cinnamon, cardamom and cloves have been widely used for medicinal purposes as well as essential cooking ingredients for flavor. The objective of the research was to investigate the antioxidant content, antioxidant capacity, and inhibition of lipid and carbohydrate metabolizing enzyme activities of selected spices (cinnamon, cardamom & cloves) methanol (ME) and water extracts (WE). The phytochemical content was determined by total phenolic and total flavanoid content. The antioxidant potential was determined by measuring 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and Ferric Reducing Antioxidant Power (FRAP) in spice’s (ME) and (WE) extracts. Total phenolic (GAE mg/100g dry weight) and flavonoid (mg CE/100g dry weight) content were the highest in Cloves (ME) 174.4 and 101.06. The lowest values for phenolic content were seen in ME and WE of Cardamom at 31.24 and 7.55. The DPPH IC50 values ranged from 0.22mg/mL (Cloves ME) to 0.60mg/mL (Cardamom ME). FRAP (μmol Fe2+/100g dry weight) for Cinnamon, Cardamom (ME) was 2438.5 and 325. Clove (ME) had a significantly higher reducing potential of 6888.5 which might have been attributed by the high amounts of phenolics and flavonoids in the spice. FRAP in spice extracts (WE) was lower with values of 2296.5 and 218.5 and 2310.5, respectively. The highest inhibition of the α-glucosidase was observed by Clove (ME) 86.5%, which also had the highest amylase enzyme inhibition at 71%. However, inhibition of the lipase enzyme was highest by the Cinnamon (WE) extracts 44.3%. The potential of phytochemicals in spices was studied and if consumed in high amounts could offer antioxidative properties and regulate key digestive enzymes which may lead to prevention or decreased progression of diseases such as Cancer, Diabetes and Cardiovascular diseases.

A Comparison of the Antioxidative and Anti-Diabetic Potential of Thermally Treated Garlic, Turmeric, and Ginger

Spices have been used for centuries for food preservation, flavors, and medicinal properties. Research suggests that garlic, turmeric, and ginger contain potent antioxidants that may prevent and/or delay chronic diseases such as cancer, diabetes, and heart disease. Heat treatment of spices may potentially increase antioxidative activity by modifying the inherent chemical structure of potent antioxidative compounds within spices. The purpose of this study was to determine the impact of thermal treatment of garlic, ginger, and turmeric on total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing antioxidant potential (FRAP), trolox activity (TEAC), lipase, a-amylase, and a-glucosidase inhibition. Conventional stovetop heating of selected spices was performed followed by methanolic and aqueous extractions (1 - 5 minutes;70°C - 130°C). Overall methanolic extracts had higher phytochemical, antioxidative, and anti-diabetic potential. However, aqueous garlic extracts exhibited higher phytochemical and antioxidative potential over methanolic garlic extracts. The highest TPC for aqueous garlic extracts was observed at 1 minute (14.11 mg GAE/g) while methanolic garlic extracts at 1 minute were significantly lower (1.72 mg GAE/g). Methanolic turmeric extracts had highest TPC at 5 minutes (28.55 mg GAE/g). Time and temperature influenced antioxidant activity in the spices. Turmeric and ginger (methanolic extracts) resulted in higher percent inhibition of DPPH radical with an increase in time (5 minute) turmeric (86.9%) and ginger (79.09%) at 7.9 mg/mL concentration. The results of this study revealed both solvent and time for thermal treatment of spices influenced antioxidative potential as determined using DPPH and FRAP assays. Therefore, the use of thermal application on spices presents promise in potentiating the antioxidant content and thereby their potential health promoting properties. Spices are utilized in the U.S. food industry and increasing their use as a natural antioxidant preservative and flavoring agent may have beneficial impact in food product development.

Assessing the Impact of Land-Use Land-Cover Change on Stream Water and Sediment Yields at a Watershed Level Using SWAT

Flint River watershed is located in northern Alabama and southern Tennessee, USA and is home to several species of rare, threatened, or endangered plants and animals in a rapidly urbanizing area. Dominant land uses are forest and agricultural, with row crops and livestock production as major farm enterprises. Soil and Water Assessment Tool (SWAT), a deterministic hydrologic model that can predict hydrologic conditions over various temporal and spatial scales, was used to simulate the hydrologic response of the watershed to land-use/land cover (LULC) change. Analysis between observed and predicted stream flow demonstrated that the initial SWAT model run requires calibration of stream parameters in order to give a more accurate output from the model. The calibration was performed with sequential uncertainty fitting, ver. 2 (SUFI-2) in the SWAT Calibration Uncertainty Program. After calibration, stream sediment yield values were compared by sub-basin between a current (2001) and three future (2030) land use scenarios, in order to identify areas in the watershed that were the most susceptible to increased sediment yield in the future. The future growth scenarios (smart, plan and sprawl) were created using the ArcGIS extension, Prescott Spatial Growth Model. Sub-basins with the greatest sensitivity for larger sediment yields were identified and prioritized for conservation efforts.

Modulation of Anti-Microbial Resistant <i>Salmonella heidelberg</i>Using Synbiotics (Probiotics and Prebiotics) in Two <i>In-Vitro</i>Assays (Cross-Streaking and Agar Wells Diffusion)

Salmonellosis is the most prevalent bacterial foodborne disease in many countries worldwide. Utilization of probiotics is one of the most accepted ways to reduce Salmonella, especially lactic acid bacteria, as it has proven to reduce the enteric pathogens in monogastric and ruminant livestock animals through different mechanisms such as antimicrobials production, competitive adhesion to the gastrointestinal tract, and immune stimulation. Prebiotics could be utilized solely for health benefits as an alternative to probiotics or in addition to probiotics for a synergistic effect known as synbiotics. The aim of this study was to compare effects of different probiotic strains (Lactobacillus acidophilus (La-14), Lactobacillus paracasei (Lpc-37), Streptococcus thermophiles (St-21), Bifidobacterium bifidum (Bb-06), and Aspergillus niger (ATCC®16888TM) and without prebiotics (Mannose;Xylose;Galactooligosaccharides GOS;Inulin;and Dandelion extract) on lowering Salmonella heidelberg CFU in vitro. Different inhibition levels probiotic strains were assessed and compared in the presence and absence of 2.5% prebiotic compounds using cross-streaking and agar well diffusion assays. Recommendations for the growth of selected microorganisms such as temperature and oxygen conditions were taken into consideration. All the analysis was conducted in triplicates. The results showed that all the probiotics strains except S. thermophiles were able to significantly (P < 0.05) inhibit the growth of S. heidelberg in at least one of the assays. The difference in inhibition percentage confirms that probiotic strains have multiple inhibition mechanisms, such as production of antimicrobials, lower pH by producing organic acids (acetic acid, lactic acid, etc.), and inhibition of pathogen’s virulence factor expression, and production of lipopolysaccharide solubilizing compounds.

The Anti-Diabetic Potential of Thermally Treated Garlic, Turmeric, and Ginger in Pre-Diabetic Male Wistar Rat Model

Spices (turmeric (T), ginger (GI), and garlic (GA) (TGG)) have been used for centuries for food preservation, flavors, and medicinal properties. Research suggests that TGG contain potent antioxidants that may prevent and/or delay chronic diseases such as cancer, diabetes, and heart diseases. Heat treatment of spices may potentially increase antioxidative activity by modifying the inherent chemical structure of potent antioxidative compounds in spices. The purpose of this study was to determine the anti-diabetic potential of thermally treated TGG on Wistar male rats. Two-week-old male Wistar rats were randomly assigned to 8 groups (N = 24, n = 3) including control AIN-93G Diet (C) and high fat (HFD) and high sugar (HS) (glucose 10%) diet and treatment HFD/HS diets containing T, GA, GI (1% and 2%) singly for 11 weeks. Weekly feed intake, body weight, and blood glucose levels were recorded. Rats were sacrificed at 13 wks. by CO2 asphyxiation. Liver, pancreas, adipose (thigh), cecum, femur, urine, and serum samples were collected for quantitative determination of detoxification and antioxidative enzyme analysis, bone mineralization, and cholesterol using standard protocol. Of spice-incorporated diets, rats fed turmeric (1%) exhibited the lowest reduction in blood glucose levels at 90 mg/dL compared to the control 58 mg/dL. Additionally rats fed TGG at both concentrations resulted in an induction of antioxidant (GSH) and antioxidant enzyme (GPx) activity with significantly (p ≤ 0.05) higher levels compared to the control. Serum total cholesterol levels were lower in spice-incorporated diets compared to control HFD/HS fed rats. Therefore, the use of thermal application on spices presents promise in potentiating the antioxidant effects and thereby their potential health promoting properties.

Feeding Soy with Probiotic Attenuates Obesity-Related Metabolic Syndrome Traits in Obese Zucker Rats

Obesity has reached pandemic levels, being a major concern of health. Overweight and obesity are the precursors for metabolic disturbances in the body. Probiotics and prebiotics administrations have shown to reduce the characteristics of obesity-induced metabolic syndrome in animals. The present study examined the effects of dietary supplementation of soybean meal and Bifidobacterium longum (BB536) singly and in combination on obesity-related traits in obese Zucker rats. Control group rats were fed with AIN93-M diet and treatment groups were fed with soybean meal (5 % or 10%) and Bifidobacterium longum (0.1%) in single and combinations for 100 days. Weight gain, feed intake, and % of fat in liver were recorded. Serum biochemical parameters such as cholesterol, triglycerides, insulin and glucose were analyzed. Activities of liver enzymatic markers (alanine aminotransferase (ALT), gamma glutamyl-transferase (GGT), and alkaline phosphatase (ALP)) were determined. Dietary supplementation of soymeal at 10% with B. longum reduced the weight gain by 30% and liver fat content by 35%. Feeding Bifidobacterium longum alone did not have any effect in analyzing serum biochemical parameters and activity of liver enzymatic markers. Serum glucose and insulin levels in rats were lowered by 18% - 24% and 22% - 25% respectively when fed with administration of combinational feeding of soymeal at 5% and 10% with Bifidobacterium longum. Hepatic enzyme activity was reduced by 1.3 fold with the combinational diet at higher concentration (soy 10%). The present study provides evidence that supplementation with soymeal with probiotic, B. longum attenuates the metabolic disorders induced by obesity in obese Zucker rats.

Synthesis and Spectroscopic Characterization of Eight Chloro Cyclopentadienyl Titanium Bis (O, O-Dialkyl and Alkylene Dithiophosphate) Compounds

A series of new complexes, CpTiCl[S2P(OR)2]2 (where R) Et, n-Pr, i-Pr, Bui, Ph) and CpTiCl [S2POGO]2 (where G) –CH2CMe2CH2-, -CMe2CMe2-) have been prepared by the drop wise addition of the appropriate O, O’-dialkyl or -alkylene dithiophosphoric acid to cyclopentadienyl titanium trichloride in 1:2 molar ratio and refluxed in benzene solution. The new compounds were characterized by molecular weight measurements elemental analyses and spectroscopic studies (1H, 13C, and 31P NMR, and in-frared). We suggest a distorted tetrahedron structure of these new complexes and the dithioligand behaves as bidentate ligand.

Analysis of Spectral Signatures of Silicone-Based Sealant Materials Used in Residential and Commercial Buildings

In the construction industry, silicone is primarily used as sealant material to fill gaps and cracks providing water and air-tightness to vertical construction projects reducing energy usage bills and enhancing the integrity of construction materials. This paper reports the results of spectral analysis of commonly used building sealant materials used in residential and commercial buildings. A dozen commercially available silicone-based sealant materials composed of different ingredients representing three manufacturer brands are characterized using Raman and UV-VIS-NIR spectroscopic techniques. The characteristic vibrational fingerprints of the selected sealant materials are summarized, and the Raman and reflectance spectra of the samples are also presented. It is observed that most of the samples appear to have similar vibrational band assignments and reflectance spectra. However, analysis of the Raman spectral positions and the reflectance spectra reveals that there are distinct differences among the sealant materials.

The Expressed Parasitism Genes in the Reniform Nematode (<i>Rotylenchulus reniformis</i>)

The reniform nematode (RN), Rotylenchulus reniformis, is an agriculturally important pest with a broad host range that results in a large economic impact in tropical, subtropical and in warm temperate zones. In an initial effort to understand the transcriptome and gene expression in RN, we present EST results that reveal numerous putative parasitism-related genes some of which play roles in plant cell wall modification. The characterized contigs included 8362 (40.6%) matches to unique proteins. Coding contigs predicted were 10,656 (51.7%) or 3079 (14.9%), that was similar to those identified in Brugia malayi and Caenorhabditis elegans as reference organisms respectively. Specific transcripts studied in more detail include putative plant parasitism genes, prominent among them were several plant cell wall modification genes. Contigs matching 14 parasitism genes found in sedentary endoparasitic nematodes included expansins, hexosaminidase, glycosyl hydrolases family, 14-3-3 protein, xylanases, glutathione peroxidase, pectate lyase, β-1,4-endoglucanase, major sperm protein, aminopeptidase, c-type lectin, chitin synthase, FMR famide-like peptide, and calreticulin. These genes function in suppression of host defenses and development of feeding sites.

Thin Cell Layer (TCL) Culture System for Herbal Biomass Production and Genetic Transformation of Bacopa monnieri L. Wettst.

Bacopa monnieri (L.) Wettst. (Scrophulariaceae) is a highly sought after medicinal plant with therapeutic properties as cognition enhancer as well as for other brain and body functions. Research was conducted to optimize a thin cell layer explant based micropropagation system to assist mass propagation. Thin cell layers (TCL) derived from leaf and internode segments were used as explants. Murashige and Skoog medium was used to formulate shoot induction, elongation, and rooting media. Shoot induction media were prepared by supplementing three concentrations (0.1, 1.0, and 10.0 μM) of four cytokinins 6-benzylaminopurine, 2-isopentenyl-adenine, 6-3-Hydroxybenzylaminopurine, and thidiazuron to study adventitious shoot bud induction response. An optimum shoot bud induction response was observed on MS medium supplemented with 10.0 μM 6-benzylaminopurine for both leaf and stem transverse thin cell layer (tTCL) explants. The average number of shoot buds from leaf tTCL explants was 59, whereas, on an average, 33 shoot buds were regenerated from internode tTCL explants. Elongation of adventitious shoot buds was achieved best in a liquid medium using Liquid Lab Rocker® system. Elongated shoots recorded 100% rooting in MS medium supplemented with 5 μM indole butyric acid. Bacopa micropropagation employing tTCL explants for initial shoot bud induction and using LLR® boxes in subsequent elongation step can achieve cost effective way to regenerate high volume of plantlets and biomass required for herbal industry. Leaf and stem tTCL explants both were suitable for Agrobacterium tumefaciens (EHA105) mediated genetic transformation. Successful transformation was scored within three days of co-cultivation with Agrobacterium suspension on the basis of Enhanced Green Fluorescent Protein (EGFP) expression as an early and non-destructible screening device. Transformation frequencies of 83% and 76% were accomplished for leaf and stem tTCL explants, respectively. Greenhouse grown Bacopa plants were analyzed as fresh and dry methanolic extracts for total polyphenol content (811.93 ± 7.98 and 814 ± 17.64 GAE mg g-1) and the Trolox Equivalent Antioxidant Capacity values were 1918.25 ± 173.12 and 3163.14 ± 403.25 μmol/g, respectively.

Characterization of Fluoride Phosphors for Diode Pumped Solid-State Lighting Applications

Phosphor coated diodes are critical to the lighting industry. Rare-earth doped fluoride phosphors are characterized in this work. Spectroscopy and lifetime measurements of CaF2: Dy3+, LaF3: Eu3+ and Tb3+-doped LaF3 and CaF2 crystals were performed by irradiating the samples with 405 and 375 nm diode lasers. Chromaticity diagrams are developed from spectral measurements. Dy3+-doped CaF2 revealed bright white light emission having peaks at 492, 570 and 654 nm. The measured color coordinates are x = 0.322 and y = 0.340 for Dy3+-doped CaF2 and these values are close to those of sunlight and the coordinated color temperature is 6147 K, under 405 m laser excitation. Eu3+-doped LaF3 revealed twenty emission peaks in the visible wavelength region. The color coordinates measured for LaF3: Eu3+ are x = 0.283 and y = 0.293 under 405 nm diode laser excitation and the color temperature is 9557 K. Eu3+-doped LaF3 provides cool white-light, under 405 nm diode laser excitation. Tb3+-doped fluoride crystals revealed bright white light under low power diode laser excitation. The measured color coordinates for Tb3+-doped CaF2 are x = 0.329 and y = 0.558 and the color temperature is 7713 K. The color coordinates for LaF3: Tb3+ are x = 0.342 and y = 0.365 and the coordinated color temperature is 5370 K. These values are close to those of sunlight.

Temperature Dependent Surface Resistivity Measures of Commercial, Multiwall Carbon Nanotubes (MWCNT), and Silver Nano-Particle Doped Polyvinyl Alcohol (PVA) Films

Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made from Polyvinyl Alcohol (PVA) have received considerable attention in recent years. The investigation of surface resistivities of both such films, to this point, has received far less consideration in comparison to pyroelectric effects. In this research, we report temperature dependent surface resistivity measurements of commercial, and of multiwall carbon nanotubes (MWCNT), or Ag-nanoparticle doped PVA films. Without any variation in the temperature range from 22°C to 40°C with controlled humidity, we found that the surface resistivity decreases initially, reaches a minimum, but rises steadily as the temperature continues to increase. This research was conducted with the combined instrumentation of the Keithley Model 6517 Electrometer and Keithley Model 8009 resistivity test fixture using both commercial and in-house produced organic thin films. With the objective to quantify the suitability of PVDF and PVA films as IR detector materials, when using the surface resistivity phenomenon, instead of or in addition to the pyroelectricity, surface resistivity measurements are reported when considering bolometry. We found that the surface resistivity measurements on PVA films were readily implemented.