The current imperfect understanding about the adsorption behavin smectites and vermiculites (Rich... more The current imperfect understanding about the adsorption behavin smectites and vermiculites (Rich, 1960, 1968; Coulter, ior of heavy metals on hydroxyaluminum (HyA)-and hydroxyalumi-1969; Barnhishel and Bertsch, 1989). The irreversible nosilicate (HAS)-interlayered phyllosilicates led us to conduct this study. We examined the adsorption behavior of Cd, Zn, and Pb on adsorption of HyA and HAS cations to the slicate sursynthetically prepared HyA-and HAS-montmorillonite (Mt) comface causes a great reduction in permanent negative plexes in comparison with that on untreated Mt. A very dilute initial charge with a substantial increase in pH-dependent negmetal concentration of 10 Ϫ6 M in 0.01 M NaClO 4 background was ative charge, a drastic reduction in internal surface area used in all the adsorption systems. The presence of HyA and HAS with a slight increase in external surface area (Inoue and polymers on Mt greatly promoted the adsorption of all three metals.
In 2:1 type silicate clays, HyA and HAS interlayers are mixed solutions on synthetically prepared... more In 2:1 type silicate clays, HyA and HAS interlayers are mixed solutions on synthetically prepared Hydroxyaluminum (HyA)common in acid to slightly acid soils. As a consequence, and Hydroxyaluminosilicate (HAS)-montmorillonite (Mt) complexes within the pH range 4 to 8. Initial concentrations of each metal (Me I) several attempts have been made to synthesize such of 1 ϫ 10 Ϫ6 M in binary systems and 1 ϫ 10 Ϫ6 , 2 ϫ 10 Ϫ5 , 5 ϫ 10 Ϫ5 M interlayers in smectites and vermiculites (Rich, 1960, in ternary systems were used in a background electrolyte of 0.01 M
There is a clear gap in the understanding of the desorption patterns of metals sorbed on soils an... more There is a clear gap in the understanding of the desorption patterns of metals sorbed on soils and clays, despite their importance in the mobility, transport and fate of metals in natural environments. In this study, we investigated the desorption behavior of Cd, Zn and Pb ...
In this study, concentrations of radon in residential buildings were investigated in order to est... more In this study, concentrations of radon in residential buildings were investigated in order to establish the pattern of variation within the buildings in these environments. The target rooms were the bedroom, bathroom/ toilet, living room and kitchen. One hundred and thirty-seven (137) rooms were selected using multi-stage sampling protocol. Solid state nuclear track detectors, CR-39, were employed for the measurement so as to obtain average radon concentration in each room. Radon concentrations vary from 3.63 – 12.17 Bq/m 3 , 3.09 – 11.62 Bq/m 3 , 3.43 – 13.26 Bq/m 3 , and 4.09 – 13 Bq/m 3 with mean of 6.75 ± 0.09, 6.89 ± 0.08, 6.44 ± 0.09 and 7.43± 0.09 Bq/m 3 respectively in the bedrooms, bathrooms/ toilets, living rooms and kitchens. Therefore, the pattern of radon concentration variations observed in this study is of this order: bedroom < bathroom/toilet < kitchen < living room. SELF-REPORTED RESPIRATORY SYMPTOMS IN HEALTHY ADULTS WITH HIGH HOME RADON LEVELS Karen M. Bu...
Hydroxy-interlayered vermiculite (Vt) and montmorillonite (Mt) clays were prepared in the laborat... more Hydroxy-interlayered vermiculite (Vt) and montmorillonite (Mt) clays were prepared in the laboratory through reacting <2 μm sized Vt and Mt clays with hydroxyaluminum (HyA) and hydroxyaluminosilicate (HAS) ionic solutions having final Al concentrations of around 4 mM; OH/Al molar ratios of 1.0, 2.0, and 2.5; and Si/Al atomic ratios of around 0.00, 0.25, 0.50, and 1.00. After reaction, varying extents of Al and Si fixation on Vt and Mt clays were recorded due to different Si/ Al and OH/Al ratios of the reacting HyA and HAS ionic solutions suggesting different degrees of interlayer filling with hydroxy-materials in the resultant HyA/ HAS-Vt/Mt complexes. Ammonium fixation and exchange capacities of these HyA/ HAS (OH/Al=1.0, 2.0, and 2.5)-Vt and HyA/HAS (OH/Al=2.0)-Mt complexes were studied in comparison to untreated Vt and Mt with added NH4 at different rates ranging from around 20 to 300 meq/100 g. Untreated Vt clay showed NH4 fixation as high as 91 meq/100 g in contrast to only ...
International Journal of Applied Agricultural Sciences, 2017
Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid h... more Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid hormone metabolism, strengthens anti-oxidant defense system and immune system. However, about 800 million people worldwide are believed to be deficient in Se which is attributed to low Se levels in the soil. This is because Se in plant and animal products in human diet depends upon the available Se in the soil. Deficiency of Se can be prevented or treated by adequate dietary intake or through direct supplementation. There have been reports that patients with dilated cardiomyopathy, HIV viral loads and cancer have responded to Se supplementation. However, food fortification has been found to be more efficient than supplementation. Both agronomic biofortification and genetic biofortification have been used to increase Se content of food crops and animal products. Genetic engineering makes use of key genes of Se hyperaccumulators to increase Se accumulating potential of food crops. Agronomic biofortification increases Se content of food crops by adding Se rich fertilizers to the soil or foliar application of Se. Selenium can also be added to animal diets or feedstuff to increase Se content of meat, eggs, and milk. Although inorganic forms of Se are approved as feed additives, they are less efficient than organic sources such as selenomethionine (SeMet) which is the dominant form in plants and animals. Animal products have been found to have higher Se content than plant products with fish having the highest Se content. Fruits and vegetables have a low content of Se probably because of their low protein content. Recommendations for dietary intake of Se vary with country, age and sex. There are concerns that the present recommended Se daily allowance may not be adequate due to discovery of other selenoenzymes with higher Se requirements than gluthathione peroxidase. There may be a need to review the current recommended daily allowance for Se in order to improve human health.
Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass... more Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass native to southeastern United States. Recently, there is a growing interest in its development as a grazing and haying forage crop due to its wide area of adaptation across this region. Consequently, there is a great need for the evaluation of its forage quality by rapid, but accurate analytical methods like Near-Infrared Reflectance Spectroscopy (NIRS). In this study, acceptable NIRS calibration models were developed for: dry matter, DM (n = 113, R 2 = 0.904, RSCD = 2.54, RSCIQ = 4.65); crude protein, CP (n = 113, R 2 = 0.974, RSCD = 5.16, RSCIQ = 5.92); acid detergent fiber, ADF (n = 116, R 2 = 0.896, RSCD = 2.35, RSCIQ = 1.28); neutral detergent fiber, NDF (n = 118, R 2 = 0.934, RSCD = 2.53, RSCIQ = 3.38); digestible dry matter, DDM (n = 116, R 2 = 0.895, RSCD = 2.36, RSCIQ = 1.35); dry matter intake, DMI (n = 115, R 2 = 0.924, RSCD = 2.40, RSCIQ = 2.53); and relative feed value, RFV (n = 114, R 2 = 0.932, RSCD = 2.94, RSCIQ = 2.81). Prediction of independent validation sets yielded good agreement between the NIRS predicted values and the laboratory reference values for each of:
To address the concern that irrigation provides sufficient water to match the crop needs, while n... more To address the concern that irrigation provides sufficient water to match the crop needs, while not impeding oxygen availability to the roots, we conducted an experiment to develop suitable irrigation schedule(s) for greenhouse tomato (Lycopersicon esculentum Mill.) on rockwool. The experimental treatments incorporated the electrical conductivity (EC) of the nutrient solution in the rockwool slab (slab-EC) along with the water content (WC) in the rockwool slab (slab-WC) as the irrigation decision-making variables. They were: slab-WC ≤ 70% or slab-EC ≥ 1.4× normal or more (T1), slab-WC ≤ 70% or slab-EC ≥ 1.7× normal or more (T2), slab-WC ≤ 80% or slab-EC ≥ 1.4× normal or more (T3), slab-WC ≤ 80% or slab-EC ≥ 1.7× normal or more (T4), and the combined weight loss (WL) 700 g or more (T5) and WL 500 g or more (T6), in which “normal” means the feed solution EC as recommended in the seasonal fertigation schedule for a spring–summer tomato crop. The data on early-season marketable yield, t...
In rockwool-grown greenhouse vegetables, unsatisfactory spatial root development, rapid root coll... more In rockwool-grown greenhouse vegetables, unsatisfactory spatial root development, rapid root collapse, and increased incidence of root diseases are very common. Improved water management could alleviate these problems to some extent, because this could favorably modify water-air distribution in the slab, thereby improving greenhouse vegetable yield and quality. The present study tested six irrigation strategies on the productivity of rockwool-grown tomatoes (cv. Rapsodie) during Jan.o–Aug. 2004. The four treatments, based on electronic Grodan? water content meters (WCMs), received irrigations when the slab water content (SWC) was ≈60%, 70%, 80%, and 90% while the other two treatments, based on balances, applied irrigations after a 700- or 500-g loss in the daily-adjusted slab weight (LDASW). Initially, we noticed a heterogeneous EC build-up in the slabs across various treatments, which probably distorted the expression of treatment effects (if any) on plant growth, yield, and water ...
Thirty seven diverse chilli (Capsicum annuum) genotypes were studied for 22 growth, yield and fru... more Thirty seven diverse chilli (Capsicum annuum) genotypes were studied for 22 growth, yield and fruit quality traits. Multivariate analysis grouped the genotypes into 7 clusters. Cluster IV was largest containing 14 genotypes. Inter cluster distance was maximum between cluster V and VII (248.09), and minimum between cluster I and II (57.80). Cluster VII was most heterogeneous (intra-cluster divergence value 191.25) and Cluster II was most homogeneous (30.25). Genotypes were also analyzed for peroxidase enzyme polymorphism using gel electrophoresis which resulted seven electrophoretic bands (Rf 0.19 to 0.59) and grouped the genotypes into 6 zymotypes. Zymotype P4 included maximum (13) number of genotypes. Number of clusters in peroxidase and multivariate analysis were almost same but distribution of genotypes varied. 73% of total genotypes showed similar pattern of grouping suggesting that the two methods are complementary to each other and should be carried out simultaneously to deter...
Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be p... more Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems for forage in addition to their traditional use as protein and/or oil yielding crops. Rapid and low cost methods of analyzing plant forage quality would be helpful for nutrition management of livestock. We developed and validated calibration models using Near-infrared Reflectance Spectroscopic (NIRS) analysis for 27 different forage quality parameters of organically grown sunflower and soybean leaves or reproductive parts. Crops were managed under conventional tillage or no-till with a cover crop of wheat before soybean and ryecrimson clover before sunflower. From a population of 120 samples from both crops, covering multiple sampling dates within the treatments, calibration models were developed utilizing spectral information covering both visible and NIR region of 61-85 randomly chosen samples using modified partial least-squares (MPLS) regression with internal cross validation. Within MPLS protocol, we compared nine different math treatments on the quality of the calibration models. The math treatment "2,4,4,1" yielded the best quality models for all but starch and simple sugars (r 2 = 0.699-0.999; where the 1st digit is the number of the derivative with 0 for raw spectra, 1 for first derivative, and 2 for second derivative, the 2nd digit is the gap over which the derivative is calculated, the 3rd digit is the number of data points in a running average or smoothing, and the 4th digit is the second smoothing).
International Journal of Applied Agricultural Sciences, 2016
Selenium (Se), an essential nutrient for animals and humans, occurs as selenoproteins in enzymes.... more Selenium (Se), an essential nutrient for animals and humans, occurs as selenoproteins in enzymes. It is very important in animal nutrition because it functions as an anti-oxidant assisted by vitamin E. Se deficiency is a major problem which can be reduced or prevented by supplementation with inorganic or organic sources of Se. However, excessive supplementation and consumption of Se accumulating plants may lead to Se toxicity and animal poisoning. Minimal lethal dose for animals range between 1.5 to 8 mg kg-1 Se live body weight and maximum tolerable concentration of Se in forages is 5 mg kg-1. Se deficiency in animals also depends greatly on Se content of forages and soils. Se deficient soils contain less than 0.6 mg kg-1 and can be fertilized to increase Se content of forages or pastures for animals. Forages are classified as adequate, marginally deficient and deficient in Se and contain 0.2, 0.1-0.199 and <0.1 mg kg-1 Se respectively. Silages can also be fortified with selenium to meet the requirements for Se in animals. The requirements of Se for animals need to be met to provide adequate animal and human nutrition.
International Journal of Applied Agricultural Sciences, 2016
Digestibility of "Tifton 85" Bermudagrass has been noted to be higher than most other Bermudagras... more Digestibility of "Tifton 85" Bermudagrass has been noted to be higher than most other Bermudagrass cultivars. However, the superior digestibility of Tifton-85 has not been verified based on samples from producers, nor is it known how water availability might affect this comparison. Recent past weather conditions in Georgia allowed this comparison. Much of Georgia was in severe drought in 2007 and 2008. In contrast, there was less/no drought in 2006 and 2009. In each of these years, producers submitted a substantial number of Tifton-85 and Coastal forage samples to our laboratory for lignin and "Digestible Neutral Detergent Fiber (dNDF48)" analyses. Over all years, Tifton-85 had lower lignin content than coastal. However, Tifton-85 had significantly lower lignin content only in drought free 2006 and 2009, whereas the lignin content of Coastal was unaffected by drought in 2007 and 2008. The lignin of Tifton-85 increased during these two drought years. Despite this, the dNDF48 for Tifton-85 was significantly higher than coastal in all four years, suggesting that drought had hardly any effect on the digestibility of Tifton-85. Apparently, the type of lignin in Tifton-85 is different from that in coastal. Higher dNDF48 for Tifton-85 has been attributed to its lower concentrations of ether-linked ferulic acid than in Coastal. Decreased ether bonding in lignin results in higher digestion.
Chattagram Maa-O-Shishu Hospital Medical College Journal, 2013
Background: Epidemiologic studies have reported that microalbuminuria is a risk factor for stroke... more Background: Epidemiologic studies have reported that microalbuminuria is a risk factor for stroke in men and a limited case control study found that the highest quintile of microalbuminuria values was associated with 13 fold increased risk for stroke. The goal of this study is designed to determine its relationship to risk factors for ischemic stroke. Materials and Methods: It was a prospective observational study conducted in the
Chattagram Maa-O-Shishu Hospital Medical College Journal, 2013
Background: Several epidemiological studies have identified the association of abnormal ABPI with... more Background: Several epidemiological studies have identified the association of abnormal ABPI with ischemic stroke. So the goal of this study was to determine the actual relationship of ABPI with ischemic stroke in the context of our country. Methods: This case control study was carried out in the Department of Neurology, Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh. ABPI was measured by Doppler ultrasound machine of 100 patients who were admitted to the Mitford Hospital during the study period. Among them 50 patients with Ischemic stroke, confirmed by CT/MRI scan of brain were considered as case and 50 age-sex matched individuals with one or more vascular risk factors (VRF) but without stroke were considered as control. Then the results of ABPI were compared between the two groups. Results: Among the 50 patients with ischemic stroke (case group), 74% had normal ABPI and 26% had ABPI< 0.9; on the other hand among 50 age and sex matched individuals (co...
This hydroponic experiment was conducted to determine the effects of nitrogen (N) and phosphorus ... more This hydroponic experiment was conducted to determine the effects of nitrogen (N) and phosphorus (P) levels and frond-harvesting on the effectiveness of arsenic (As)hyperaccumulator Chinese brake fern (Pteris vittata L.) to remove As from contaminated groundwater collected from south Florida. Three-month old ferns were grown in 38-L plastic tanks (two ferns per tank) containing 30-L of As-contaminated water (130 µg•L −1 As), which was amended with modified 0.25 strength Hoagland's solution #2. Two N (26 or 52 mg•L −1) and two P levels (1.2 and 2.4 mg•L −1) were tested in one experiment, whereas the effect of frond-harvesting was tested in a separate experiment. Initially, N had little effect on plant As removal whereas low P treatment was more effective than high P and As was reduced to <5 µg•L −1 in 28 d compared to 35 d. For well-established ferns, N and P levels had little effect. Reused fern, with or without harvesting the As-rich fronds, took up arsenic more rapidly so the As concentration in the groundwater declined faster (130 to ∼10 µg•L −1 in 8 h). Regardless of the treatments, most As (85-93%) was located in the aboveground tissue (rhizomes and fronds). Frond As concentrations were higher for non-harvested ferns than for ferns where fronds were partially harvested prior to treatment. Conversely, rhizomes accumulated more arsenic in ferns where fronds had been partially harvested. Low-P treatment coupled with reuse of more established ferns with or without harvesting fronds can be used to effectively remove arsenic from contaminated water using P. vittata
This field-scale hydroponic experiment investigated the effects of plant density and nutrient lev... more This field-scale hydroponic experiment investigated the effects of plant density and nutrient levels on arsenic (As) removal by the As-hyperaccumulator Pteris vittata L. (Chinese brake fern). All ferns were grown in plastic tanks containing 30 L of As-contaminated groundwater (130 µg•L −1 As) collected from South Florida. The treatments consisted of four plant densities (zero, one, two, or four plants per 30 L), two nitrogen (N) concentrations (50% or 100% of 0.25-strength Hoagland solution [HS]), and two phosphorous (P) concentrations (15% and 30% of 0.25 strength HS). While low P was more effective than high P for plant As removal initially, N levels showed little effect. At 15% P, it took 3 wk for the ferns at a plant density of four to reduce As to less than 10 µg L −1 (USEPA and WHO standard), whereas it took 4-6 wk at plant densities of one or two. For reused ferns, established plants with more extensive roots than "first-time" ferns, a low plant density of one plant/30 L was more effective, reducing As in water to less than 10 µg L −1 in 8 h. This translates to an As removal rate of 400 µg h −1 plant −1 , which is the highest rate reported to date. Arsenic-concentration in tanks with no plants as a control remained high throughout the experiment. Using more established ferns supplemented with dilute nutrients (0.25 HS with 25% N and 15% P) with optimized plant density (one plant per 30 L) reduced interplant competition and secondary contamination from nutrients, and can be recommended for phytofiltration of As-contaminated groundwater. This study demonstrated that P. vittata is effective in remediating As-contaminated groundwater to meet recommended standards.
To better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in ... more To better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in three berm soils were characterized via size distribution, total Pb concentration, water-soluble Pb, sequential extraction and X-ray diffraction (XRD). About 60% of the mid-berm soils of ranges-G and-O existed in grain sizes between 0.5 and 0.25 mm (medium sand) while range-L was most abundant in the 0.25-0.106 mm (fine sand) size fraction. All three range soils had the most accumulation of lead (60-70%) in the very coarse sand size (2.0-1.0 mm). In ranges-G and-L, the index shows a decreasing Pb enrichment with decreasing particle size, which may be a result of bullet fragmentation and abrasion in shooting range soils. Sequential extractions reveal that ranges-G and-L had the highest proportion of Pb bound to organic matter while range-O was dominated by the carbonate-bound fraction. However, a substantial proportion (one-third) of Pb in soil from the three shooting ranges was associated with carbonates. The XRD result revealed the dominance of carbonates in range-O soil, calcite in range-G soil and metallic lead in ranges-G and-O soil. The conversion of metallic lead to carbonates may be a mechanism for natural attenuation of lead in shooting range soils. Implications for remediation of shooting range soils are further discussed.
Background: Epidemiologic studies have identified hyper-homocysteinemia as a possible risk factor... more Background: Epidemiologic studies have identified hyper-homocysteinemia as a possible risk factor for atherosclerosis.The aim of my study was based on evaluation of relationship between homocysteinemia with ischemic stroke patients. Methods and materials: It was a prospective observational study conducted in the Department of Neurology, Sir Salimullah Medical College & Mitford hospital, Dhaka. Thirty six consecutive patients with ischemic stroke were analyzed by serum total homocysteine, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride and Equal number of controls same ages were compared with the case group. Result: Mean Fasting blood sugar, serum fasting total cholesterol (TC), serum fasting Low density lipoprotein (LDL) were significantly higher in case group (p=0.001). Serum TC and LDL had a positive correlation with serum homocystine a (p=0.001). Serum High density lipoprotein (HDL) had a negative correlation (p=0.718) and serum triglyceride (TG) had a negative ...
The current imperfect understanding about the adsorption behavin smectites and vermiculites (Rich... more The current imperfect understanding about the adsorption behavin smectites and vermiculites (Rich, 1960, 1968; Coulter, ior of heavy metals on hydroxyaluminum (HyA)-and hydroxyalumi-1969; Barnhishel and Bertsch, 1989). The irreversible nosilicate (HAS)-interlayered phyllosilicates led us to conduct this study. We examined the adsorption behavior of Cd, Zn, and Pb on adsorption of HyA and HAS cations to the slicate sursynthetically prepared HyA-and HAS-montmorillonite (Mt) comface causes a great reduction in permanent negative plexes in comparison with that on untreated Mt. A very dilute initial charge with a substantial increase in pH-dependent negmetal concentration of 10 Ϫ6 M in 0.01 M NaClO 4 background was ative charge, a drastic reduction in internal surface area used in all the adsorption systems. The presence of HyA and HAS with a slight increase in external surface area (Inoue and polymers on Mt greatly promoted the adsorption of all three metals.
In 2:1 type silicate clays, HyA and HAS interlayers are mixed solutions on synthetically prepared... more In 2:1 type silicate clays, HyA and HAS interlayers are mixed solutions on synthetically prepared Hydroxyaluminum (HyA)common in acid to slightly acid soils. As a consequence, and Hydroxyaluminosilicate (HAS)-montmorillonite (Mt) complexes within the pH range 4 to 8. Initial concentrations of each metal (Me I) several attempts have been made to synthesize such of 1 ϫ 10 Ϫ6 M in binary systems and 1 ϫ 10 Ϫ6 , 2 ϫ 10 Ϫ5 , 5 ϫ 10 Ϫ5 M interlayers in smectites and vermiculites (Rich, 1960, in ternary systems were used in a background electrolyte of 0.01 M
There is a clear gap in the understanding of the desorption patterns of metals sorbed on soils an... more There is a clear gap in the understanding of the desorption patterns of metals sorbed on soils and clays, despite their importance in the mobility, transport and fate of metals in natural environments. In this study, we investigated the desorption behavior of Cd, Zn and Pb ...
In this study, concentrations of radon in residential buildings were investigated in order to est... more In this study, concentrations of radon in residential buildings were investigated in order to establish the pattern of variation within the buildings in these environments. The target rooms were the bedroom, bathroom/ toilet, living room and kitchen. One hundred and thirty-seven (137) rooms were selected using multi-stage sampling protocol. Solid state nuclear track detectors, CR-39, were employed for the measurement so as to obtain average radon concentration in each room. Radon concentrations vary from 3.63 – 12.17 Bq/m 3 , 3.09 – 11.62 Bq/m 3 , 3.43 – 13.26 Bq/m 3 , and 4.09 – 13 Bq/m 3 with mean of 6.75 ± 0.09, 6.89 ± 0.08, 6.44 ± 0.09 and 7.43± 0.09 Bq/m 3 respectively in the bedrooms, bathrooms/ toilets, living rooms and kitchens. Therefore, the pattern of radon concentration variations observed in this study is of this order: bedroom < bathroom/toilet < kitchen < living room. SELF-REPORTED RESPIRATORY SYMPTOMS IN HEALTHY ADULTS WITH HIGH HOME RADON LEVELS Karen M. Bu...
Hydroxy-interlayered vermiculite (Vt) and montmorillonite (Mt) clays were prepared in the laborat... more Hydroxy-interlayered vermiculite (Vt) and montmorillonite (Mt) clays were prepared in the laboratory through reacting <2 μm sized Vt and Mt clays with hydroxyaluminum (HyA) and hydroxyaluminosilicate (HAS) ionic solutions having final Al concentrations of around 4 mM; OH/Al molar ratios of 1.0, 2.0, and 2.5; and Si/Al atomic ratios of around 0.00, 0.25, 0.50, and 1.00. After reaction, varying extents of Al and Si fixation on Vt and Mt clays were recorded due to different Si/ Al and OH/Al ratios of the reacting HyA and HAS ionic solutions suggesting different degrees of interlayer filling with hydroxy-materials in the resultant HyA/ HAS-Vt/Mt complexes. Ammonium fixation and exchange capacities of these HyA/ HAS (OH/Al=1.0, 2.0, and 2.5)-Vt and HyA/HAS (OH/Al=2.0)-Mt complexes were studied in comparison to untreated Vt and Mt with added NH4 at different rates ranging from around 20 to 300 meq/100 g. Untreated Vt clay showed NH4 fixation as high as 91 meq/100 g in contrast to only ...
International Journal of Applied Agricultural Sciences, 2017
Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid h... more Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid hormone metabolism, strengthens anti-oxidant defense system and immune system. However, about 800 million people worldwide are believed to be deficient in Se which is attributed to low Se levels in the soil. This is because Se in plant and animal products in human diet depends upon the available Se in the soil. Deficiency of Se can be prevented or treated by adequate dietary intake or through direct supplementation. There have been reports that patients with dilated cardiomyopathy, HIV viral loads and cancer have responded to Se supplementation. However, food fortification has been found to be more efficient than supplementation. Both agronomic biofortification and genetic biofortification have been used to increase Se content of food crops and animal products. Genetic engineering makes use of key genes of Se hyperaccumulators to increase Se accumulating potential of food crops. Agronomic biofortification increases Se content of food crops by adding Se rich fertilizers to the soil or foliar application of Se. Selenium can also be added to animal diets or feedstuff to increase Se content of meat, eggs, and milk. Although inorganic forms of Se are approved as feed additives, they are less efficient than organic sources such as selenomethionine (SeMet) which is the dominant form in plants and animals. Animal products have been found to have higher Se content than plant products with fish having the highest Se content. Fruits and vegetables have a low content of Se probably because of their low protein content. Recommendations for dietary intake of Se vary with country, age and sex. There are concerns that the present recommended Se daily allowance may not be adequate due to discovery of other selenoenzymes with higher Se requirements than gluthathione peroxidase. There may be a need to review the current recommended daily allowance for Se in order to improve human health.
Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass... more Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass native to southeastern United States. Recently, there is a growing interest in its development as a grazing and haying forage crop due to its wide area of adaptation across this region. Consequently, there is a great need for the evaluation of its forage quality by rapid, but accurate analytical methods like Near-Infrared Reflectance Spectroscopy (NIRS). In this study, acceptable NIRS calibration models were developed for: dry matter, DM (n = 113, R 2 = 0.904, RSCD = 2.54, RSCIQ = 4.65); crude protein, CP (n = 113, R 2 = 0.974, RSCD = 5.16, RSCIQ = 5.92); acid detergent fiber, ADF (n = 116, R 2 = 0.896, RSCD = 2.35, RSCIQ = 1.28); neutral detergent fiber, NDF (n = 118, R 2 = 0.934, RSCD = 2.53, RSCIQ = 3.38); digestible dry matter, DDM (n = 116, R 2 = 0.895, RSCD = 2.36, RSCIQ = 1.35); dry matter intake, DMI (n = 115, R 2 = 0.924, RSCD = 2.40, RSCIQ = 2.53); and relative feed value, RFV (n = 114, R 2 = 0.932, RSCD = 2.94, RSCIQ = 2.81). Prediction of independent validation sets yielded good agreement between the NIRS predicted values and the laboratory reference values for each of:
To address the concern that irrigation provides sufficient water to match the crop needs, while n... more To address the concern that irrigation provides sufficient water to match the crop needs, while not impeding oxygen availability to the roots, we conducted an experiment to develop suitable irrigation schedule(s) for greenhouse tomato (Lycopersicon esculentum Mill.) on rockwool. The experimental treatments incorporated the electrical conductivity (EC) of the nutrient solution in the rockwool slab (slab-EC) along with the water content (WC) in the rockwool slab (slab-WC) as the irrigation decision-making variables. They were: slab-WC ≤ 70% or slab-EC ≥ 1.4× normal or more (T1), slab-WC ≤ 70% or slab-EC ≥ 1.7× normal or more (T2), slab-WC ≤ 80% or slab-EC ≥ 1.4× normal or more (T3), slab-WC ≤ 80% or slab-EC ≥ 1.7× normal or more (T4), and the combined weight loss (WL) 700 g or more (T5) and WL 500 g or more (T6), in which “normal” means the feed solution EC as recommended in the seasonal fertigation schedule for a spring–summer tomato crop. The data on early-season marketable yield, t...
In rockwool-grown greenhouse vegetables, unsatisfactory spatial root development, rapid root coll... more In rockwool-grown greenhouse vegetables, unsatisfactory spatial root development, rapid root collapse, and increased incidence of root diseases are very common. Improved water management could alleviate these problems to some extent, because this could favorably modify water-air distribution in the slab, thereby improving greenhouse vegetable yield and quality. The present study tested six irrigation strategies on the productivity of rockwool-grown tomatoes (cv. Rapsodie) during Jan.o–Aug. 2004. The four treatments, based on electronic Grodan? water content meters (WCMs), received irrigations when the slab water content (SWC) was ≈60%, 70%, 80%, and 90% while the other two treatments, based on balances, applied irrigations after a 700- or 500-g loss in the daily-adjusted slab weight (LDASW). Initially, we noticed a heterogeneous EC build-up in the slabs across various treatments, which probably distorted the expression of treatment effects (if any) on plant growth, yield, and water ...
Thirty seven diverse chilli (Capsicum annuum) genotypes were studied for 22 growth, yield and fru... more Thirty seven diverse chilli (Capsicum annuum) genotypes were studied for 22 growth, yield and fruit quality traits. Multivariate analysis grouped the genotypes into 7 clusters. Cluster IV was largest containing 14 genotypes. Inter cluster distance was maximum between cluster V and VII (248.09), and minimum between cluster I and II (57.80). Cluster VII was most heterogeneous (intra-cluster divergence value 191.25) and Cluster II was most homogeneous (30.25). Genotypes were also analyzed for peroxidase enzyme polymorphism using gel electrophoresis which resulted seven electrophoretic bands (Rf 0.19 to 0.59) and grouped the genotypes into 6 zymotypes. Zymotype P4 included maximum (13) number of genotypes. Number of clusters in peroxidase and multivariate analysis were almost same but distribution of genotypes varied. 73% of total genotypes showed similar pattern of grouping suggesting that the two methods are complementary to each other and should be carried out simultaneously to deter...
Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be p... more Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems for forage in addition to their traditional use as protein and/or oil yielding crops. Rapid and low cost methods of analyzing plant forage quality would be helpful for nutrition management of livestock. We developed and validated calibration models using Near-infrared Reflectance Spectroscopic (NIRS) analysis for 27 different forage quality parameters of organically grown sunflower and soybean leaves or reproductive parts. Crops were managed under conventional tillage or no-till with a cover crop of wheat before soybean and ryecrimson clover before sunflower. From a population of 120 samples from both crops, covering multiple sampling dates within the treatments, calibration models were developed utilizing spectral information covering both visible and NIR region of 61-85 randomly chosen samples using modified partial least-squares (MPLS) regression with internal cross validation. Within MPLS protocol, we compared nine different math treatments on the quality of the calibration models. The math treatment "2,4,4,1" yielded the best quality models for all but starch and simple sugars (r 2 = 0.699-0.999; where the 1st digit is the number of the derivative with 0 for raw spectra, 1 for first derivative, and 2 for second derivative, the 2nd digit is the gap over which the derivative is calculated, the 3rd digit is the number of data points in a running average or smoothing, and the 4th digit is the second smoothing).
International Journal of Applied Agricultural Sciences, 2016
Selenium (Se), an essential nutrient for animals and humans, occurs as selenoproteins in enzymes.... more Selenium (Se), an essential nutrient for animals and humans, occurs as selenoproteins in enzymes. It is very important in animal nutrition because it functions as an anti-oxidant assisted by vitamin E. Se deficiency is a major problem which can be reduced or prevented by supplementation with inorganic or organic sources of Se. However, excessive supplementation and consumption of Se accumulating plants may lead to Se toxicity and animal poisoning. Minimal lethal dose for animals range between 1.5 to 8 mg kg-1 Se live body weight and maximum tolerable concentration of Se in forages is 5 mg kg-1. Se deficiency in animals also depends greatly on Se content of forages and soils. Se deficient soils contain less than 0.6 mg kg-1 and can be fertilized to increase Se content of forages or pastures for animals. Forages are classified as adequate, marginally deficient and deficient in Se and contain 0.2, 0.1-0.199 and <0.1 mg kg-1 Se respectively. Silages can also be fortified with selenium to meet the requirements for Se in animals. The requirements of Se for animals need to be met to provide adequate animal and human nutrition.
International Journal of Applied Agricultural Sciences, 2016
Digestibility of "Tifton 85" Bermudagrass has been noted to be higher than most other Bermudagras... more Digestibility of "Tifton 85" Bermudagrass has been noted to be higher than most other Bermudagrass cultivars. However, the superior digestibility of Tifton-85 has not been verified based on samples from producers, nor is it known how water availability might affect this comparison. Recent past weather conditions in Georgia allowed this comparison. Much of Georgia was in severe drought in 2007 and 2008. In contrast, there was less/no drought in 2006 and 2009. In each of these years, producers submitted a substantial number of Tifton-85 and Coastal forage samples to our laboratory for lignin and "Digestible Neutral Detergent Fiber (dNDF48)" analyses. Over all years, Tifton-85 had lower lignin content than coastal. However, Tifton-85 had significantly lower lignin content only in drought free 2006 and 2009, whereas the lignin content of Coastal was unaffected by drought in 2007 and 2008. The lignin of Tifton-85 increased during these two drought years. Despite this, the dNDF48 for Tifton-85 was significantly higher than coastal in all four years, suggesting that drought had hardly any effect on the digestibility of Tifton-85. Apparently, the type of lignin in Tifton-85 is different from that in coastal. Higher dNDF48 for Tifton-85 has been attributed to its lower concentrations of ether-linked ferulic acid than in Coastal. Decreased ether bonding in lignin results in higher digestion.
Chattagram Maa-O-Shishu Hospital Medical College Journal, 2013
Background: Epidemiologic studies have reported that microalbuminuria is a risk factor for stroke... more Background: Epidemiologic studies have reported that microalbuminuria is a risk factor for stroke in men and a limited case control study found that the highest quintile of microalbuminuria values was associated with 13 fold increased risk for stroke. The goal of this study is designed to determine its relationship to risk factors for ischemic stroke. Materials and Methods: It was a prospective observational study conducted in the
Chattagram Maa-O-Shishu Hospital Medical College Journal, 2013
Background: Several epidemiological studies have identified the association of abnormal ABPI with... more Background: Several epidemiological studies have identified the association of abnormal ABPI with ischemic stroke. So the goal of this study was to determine the actual relationship of ABPI with ischemic stroke in the context of our country. Methods: This case control study was carried out in the Department of Neurology, Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh. ABPI was measured by Doppler ultrasound machine of 100 patients who were admitted to the Mitford Hospital during the study period. Among them 50 patients with Ischemic stroke, confirmed by CT/MRI scan of brain were considered as case and 50 age-sex matched individuals with one or more vascular risk factors (VRF) but without stroke were considered as control. Then the results of ABPI were compared between the two groups. Results: Among the 50 patients with ischemic stroke (case group), 74% had normal ABPI and 26% had ABPI< 0.9; on the other hand among 50 age and sex matched individuals (co...
This hydroponic experiment was conducted to determine the effects of nitrogen (N) and phosphorus ... more This hydroponic experiment was conducted to determine the effects of nitrogen (N) and phosphorus (P) levels and frond-harvesting on the effectiveness of arsenic (As)hyperaccumulator Chinese brake fern (Pteris vittata L.) to remove As from contaminated groundwater collected from south Florida. Three-month old ferns were grown in 38-L plastic tanks (two ferns per tank) containing 30-L of As-contaminated water (130 µg•L −1 As), which was amended with modified 0.25 strength Hoagland's solution #2. Two N (26 or 52 mg•L −1) and two P levels (1.2 and 2.4 mg•L −1) were tested in one experiment, whereas the effect of frond-harvesting was tested in a separate experiment. Initially, N had little effect on plant As removal whereas low P treatment was more effective than high P and As was reduced to <5 µg•L −1 in 28 d compared to 35 d. For well-established ferns, N and P levels had little effect. Reused fern, with or without harvesting the As-rich fronds, took up arsenic more rapidly so the As concentration in the groundwater declined faster (130 to ∼10 µg•L −1 in 8 h). Regardless of the treatments, most As (85-93%) was located in the aboveground tissue (rhizomes and fronds). Frond As concentrations were higher for non-harvested ferns than for ferns where fronds were partially harvested prior to treatment. Conversely, rhizomes accumulated more arsenic in ferns where fronds had been partially harvested. Low-P treatment coupled with reuse of more established ferns with or without harvesting fronds can be used to effectively remove arsenic from contaminated water using P. vittata
This field-scale hydroponic experiment investigated the effects of plant density and nutrient lev... more This field-scale hydroponic experiment investigated the effects of plant density and nutrient levels on arsenic (As) removal by the As-hyperaccumulator Pteris vittata L. (Chinese brake fern). All ferns were grown in plastic tanks containing 30 L of As-contaminated groundwater (130 µg•L −1 As) collected from South Florida. The treatments consisted of four plant densities (zero, one, two, or four plants per 30 L), two nitrogen (N) concentrations (50% or 100% of 0.25-strength Hoagland solution [HS]), and two phosphorous (P) concentrations (15% and 30% of 0.25 strength HS). While low P was more effective than high P for plant As removal initially, N levels showed little effect. At 15% P, it took 3 wk for the ferns at a plant density of four to reduce As to less than 10 µg L −1 (USEPA and WHO standard), whereas it took 4-6 wk at plant densities of one or two. For reused ferns, established plants with more extensive roots than "first-time" ferns, a low plant density of one plant/30 L was more effective, reducing As in water to less than 10 µg L −1 in 8 h. This translates to an As removal rate of 400 µg h −1 plant −1 , which is the highest rate reported to date. Arsenic-concentration in tanks with no plants as a control remained high throughout the experiment. Using more established ferns supplemented with dilute nutrients (0.25 HS with 25% N and 15% P) with optimized plant density (one plant per 30 L) reduced interplant competition and secondary contamination from nutrients, and can be recommended for phytofiltration of As-contaminated groundwater. This study demonstrated that P. vittata is effective in remediating As-contaminated groundwater to meet recommended standards.
To better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in ... more To better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in three berm soils were characterized via size distribution, total Pb concentration, water-soluble Pb, sequential extraction and X-ray diffraction (XRD). About 60% of the mid-berm soils of ranges-G and-O existed in grain sizes between 0.5 and 0.25 mm (medium sand) while range-L was most abundant in the 0.25-0.106 mm (fine sand) size fraction. All three range soils had the most accumulation of lead (60-70%) in the very coarse sand size (2.0-1.0 mm). In ranges-G and-L, the index shows a decreasing Pb enrichment with decreasing particle size, which may be a result of bullet fragmentation and abrasion in shooting range soils. Sequential extractions reveal that ranges-G and-L had the highest proportion of Pb bound to organic matter while range-O was dominated by the carbonate-bound fraction. However, a substantial proportion (one-third) of Pb in soil from the three shooting ranges was associated with carbonates. The XRD result revealed the dominance of carbonates in range-O soil, calcite in range-G soil and metallic lead in ranges-G and-O soil. The conversion of metallic lead to carbonates may be a mechanism for natural attenuation of lead in shooting range soils. Implications for remediation of shooting range soils are further discussed.
Background: Epidemiologic studies have identified hyper-homocysteinemia as a possible risk factor... more Background: Epidemiologic studies have identified hyper-homocysteinemia as a possible risk factor for atherosclerosis.The aim of my study was based on evaluation of relationship between homocysteinemia with ischemic stroke patients. Methods and materials: It was a prospective observational study conducted in the Department of Neurology, Sir Salimullah Medical College & Mitford hospital, Dhaka. Thirty six consecutive patients with ischemic stroke were analyzed by serum total homocysteine, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride and Equal number of controls same ages were compared with the case group. Result: Mean Fasting blood sugar, serum fasting total cholesterol (TC), serum fasting Low density lipoprotein (LDL) were significantly higher in case group (p=0.001). Serum TC and LDL had a positive correlation with serum homocystine a (p=0.001). Serum High density lipoprotein (HDL) had a negative correlation (p=0.718) and serum triglyceride (TG) had a negative ...
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