36 research outputs found

    Assessing the needs for intermediate diaphragms in prestressed concrete girder bridges

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    Reinforced concrete Intermediate Diaphragms (IDs) are still being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed and also use of IDs increases the cost and time of construction. There is no consistency in the practice of providing IDs among various states and codes of practice and overall there is a lack of clarity on the effectiveness of IDs and their needs in prestressed concrete bridges. The objectives of this research are to assess the need of reinforced concrete (RC) IDs in PC girder bridges and to determine their effectiveness and also to search for an alternative steel diaphragm configuration which would be as effective as RC IDs and could replace them if necessary. Systematic parametric studies for various bridge configurations, which are representative of an entire range of bridge geometries with different parameters, are analyzed through simplified and solid finite element models, which were already calibrated under live loads. This study was carried out on right and skewed bridges which are simply supported and continuous. A reduction factor which could be multiplied by a load distribution factor to account for the influence of the diaphragm in load distribution was developed. To assess the effectiveness of various diaphragms in protecting the girders against the lateral impact and to determine the design forces in the steel bracing members during construction of deck, a finite element analysis was carried out using 3-D solid models. The results from the parametric studies indicated that several parameters such as skew, span length, spacing, stiffness of diaphragm and girder have different levels of influence on the effectiveness of diaphragms in live load distribution for bridges. Correction factors were developed which could quantify the ID influence on load distribution. Results from various studies indicated that a steel diaphragm section can possibly replace the RC steel diaphragms

    Cell and Molecular Biology Underpinning the Effects of PEDF on Cancers in General and Osteosarcoma in Particular

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    Cancer is becoming an increasingly common disease in which abnormal cells aggressively grow, invade, and metastasize. In this paper, we review the biological functions of PEDF (pigmented epithelium-derived factor) against cancer, with a focus on a particular type of bone cancer called osteosarcoma. PEDF is a 50 kDa glycoprotein and is a potent inhibitor of angiogenesis, via its ability to decrease proliferation and migration of endothelial cells. This paper critically examines the anticancer activities of PEDF via its role in antiangiogenesis, apoptosis-mediated tumor suppression, and increased tumor cell differentiation. Recently, an orthotopic model of osteosarcoma was used to show that treatment with PEDF had the greatest impact on metastases, warranting an evaluation of PEDF efficacy in other types of cancers

    Clinicopathological profile of colorectal polyps: retrospective analysis from tertiary care center in Southern India

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    Background: Colorectal Cancer is the fourth most commonly diagnosed and chronological changes in colorectal polyps and cancer is important in efficacy of screening strategies. In this study, we aimed to compare clinicopathological features of colorectal polyps and also aimed to characterise the distribution and the pathological features of polyps during an 18-year period divided in to two groups.Methods: This is retrospective analysis of cases that underwent colonoscopy and found to have colorectal polyps were re-viewed retrospectively for 18 year period are retrieved. 18 year period was divided in to 2001 to 2010 and 2011 to 2018.Results: Among 4230 patients underwent colonoscopy between January 2001 and September 2018, 1356 were excluded; of the remaining 2874, 986 were found to have 1,272 polyps. 306 patients had 412 polyps in 2001 to 2010 group and 680 patients had 860 polyps in 2011 to 2018 group. Adenomas on the left sided colon were significantly higher in the first time period (40.2% vs 30%, p <0.0003). Polyps on the right sided colon were significantly higher in the second time period (37.3% vs 36.9%, p <0.0005). The most common histology in the both periods is tubular adenoma. Histology of adenomas with high grade dysplasia were significantly more in first period (12.4% vs 7.6%, p <0.005).Conclusions: Our data shows shift in polyps from left side to right side colon in recent years. There was no significant change in shift in advanced adenomas from left side to right side of colon

    Soybean production potential in Africa

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    Soybean (Glycine max [L.] Merr.) could possibly become a major crop in Africa due to its many uses as a food, feed, and in industry. Also, its ability to undertake symbiotic nitrogen fixation is a great advantage over cereal crops. This study simulated yield potential across west and east Africa. A number of areas were excluded from soybean production because of inadequate early season rains to allow timely sowing of the crop. Among the remaining areas, average yields greater than 200 g m−2 were commonly simulated. Two drought traits were examined as plant modifications to increase yields. These results identified those areas and plant traits in Africa where soybean has the potential to be an important, viable crop

    The Concentration of 2-Propenyl Glucosinolate in Biofumigant Crops Influences Their Anti-Fungal Activity (In-Vitro) against Soil-Borne Pathogens

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    Abstract This study investigated the biofumigation potential of nine Brassica species/cultivars by determining the levels of 2-propenyl glucosinolate in their roots and shoots, and their in-vitro suppression of four major soil-borne pathogens of vegetable crops. Hydrolysis of 2-propenyl GSL produces volatile isothiocyanate (ITC) compounds which are known to have anti-fungal activity. HPLC results showed that 2-propenyl GSL only occurred in root and shoot residue of flowering plants of four Brassica cultivars developed for green manuring (Caliente 199 ® , Mustclean ® , Nemfix ® and BQ Mulch ® ) and in the standard (mustard seed meal) treatment Fumafert ® . Levels of 2-propenyl GSL varied several fold within the four Brassica cultivars, with 77-88% of the total concentrations recorded in the shoot tissues. In in vitro assays, the level of fungal suppression by volatiles emitted by hydrated shoot and root residues related to their content of 2-propenyl GSL, and the dose of residue applied to five soilborne test pathogens (S. minor, Rhizoctonia solani, Fusarium oxysporum, Pythium dissotocum and Rhizoctonia solani). The variation in 2-propenyl GLS levels found in the Brassica green manure crops tested provides scope for selecting cultivars with greater potential for biofumigation, and to control multiple soil-borne disease problems in vegetable farms

    Adsorption at cell surface and cellular uptake of silica nanoparticles with different surface chemical functionalizations: impact on cytotoxicity

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    International audienceSilica nanoparticles are particularly interesting for medical applications because of the high inertness and chemical stability of silica material. However, at the nanoscale their innocuousness must be carefully verified before clinical use. The aim of this study was to investigate the in vitro biological toxicity of silica nanoparticles depending on their surface chemical functionalization. To that purpose, three kinds of 50 nm fluorescent silica-based nanoparticles were synthesized: 1) sterically stabilized silica nanoparticles coated with neutral polyethylene glycol (PEG) molecules, 2) positively charged silica nanoparticles coated with amine groups and 3) negatively charged silica nanoparticles coated with carboxylic acid groups. RAW 264.7 murine macrophages were incubated for 20 hours with each kind of nanoparticles. Their cellular uptake and adsorption at the cell membrane were assessed by a fluorimetric assay and cellular responses were evaluated in terms of cytotoxicity, pro-inflammatory factor production and oxidative stress. Results showed that the highly positive charged nanoparticle, were the most adsorbed at cell surface and triggered more cytotoxicity than other nanoparticles types. To conclude, this study clearly demonstrated that silica nanoparticles surface functionalization represents a key parameter in their cellular uptake and biological toxicity

    Treatment of lung cancer using nanoparticle drug delivery systems

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    Context: One of the leading causes of cancer-associated deaths in most men and women in the Western world is lung cancer. There are various types of treatments depending on the type and the stage of the cancer. A recent type of therapy is targeted gene therapy which aims to target genes that cause lung cancer. However, this therapy has some drawbacks including lack of proper vectors for delivery. These drawbacks can potentially be overcome by using various types of nanoparticles.Objective: To review current literature on the treatment of lung cancer with nanoparticles.Methods: Researchers have attempted to treat lung cancer with a variety of types of nanoparticle matrices including lipid, polylactide-co-glycolide, albumin, poly (-pentadecalactone-co-butylene-co-succinate), cerium oxide, gold, ultra-small superparamagnetic iron oxide nanoparticles, super paramagnetic iron oxide, lipid–polycation–DNA, N-[1-(2,3-dioleoyloxyl)propyl]-NNN-trimethylammoniummethylsulfate, silica-overcoated magnetic cores, and polyethyleneglycol phosphatidylethanolamine. There are various ways in which nanoparticles enhance drug delivery, and these include encapsulation against immune response, tissue penetration, target selectivity and specificity, delivery monitoring, promoting apoptosis, and blocking pathways for cancer initiation and progression.Conclusion: In the past decade, a lot has been said about targeting of NPs for lung and other cancers, but little has been actually successfully delivered to date. Nevertheless, nanoparticles can act as good vectors for delivering drug to the target neoplastic lesions within the lung, increase cellular uptake, increase tissue penetration and help in tracking the drug. In the future, combination therapies may play a key role in the treatment of lung cancer using the existing therapies

    X-ray diffraction study of AlN / AlGaN short period superlattices

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    Short period superlattices of AlN / Al 0.08 Ga 0.92 N with the average AlN content over 60% have been investigated by high resolution x-ray diffraction. The a and c lattice constants verify these structures to be strain relaxed. Monolayer-level interface roughness, caused by the presence of threading dislocations and step-flow growth mode, is simulated and directly compared with the zeroth and ±1 satellite peak positions of the rocking curves. It was found that the observed x-ray diffraction data can be adequately described by considering primarily the presence of screw dislocations and step-flow growth mode

    Development of Dapagliflozin Solid Lipid Nanoparticles as a Novel Carrier for Oral Delivery: Statistical Design, Optimization, In-Vitro and In-Vivo Characterization, and Evaluation

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    Controlling hyperglycemia and avoiding glucose reabsorption are significant goals in type 2 diabetes treatments. Among the numerous modes of medication administration, the oral route is the most common. Introduction: Dapagliflozin is an oral hypoglycemic agent and a powerful, competitive, reversible, highly selective, and orally active human SGLT2 inhibitor. Dapagliflozin-loaded solid lipid nanoparticles (SLNs) are the focus of our present investigation. Controlled-release lipid nanocarriers were formulated by integrating them into lipid nanocarriers. The nanoparticle size and lipid utilized for formulation help to regulate the release of pharmaceuticals over some time. Dapagliflozin-loaded nanoparticles were formulated by hot homogenization followed by ultra-sonication. The morphology and physicochemical properties of dapagliflozin-SLNs have been characterized using various techniques. The optimized dapagliflozin-SLNs have a particle size ranging from 100.13 &plusmn; 7.2 to 399.08 &plusmn; 2.4 nm with 68.26 &plusmn; 0.2 to 94.46 &plusmn; 0.7% entrapment efficiency (%EE). Dapagliflozin-SLNs were optimized using a three-factor, three-level Box&ndash;Behnken design (BBD). Polymer concentration (X1), surfactant concentration (X2), and stirring duration (X3) were chosen as independent factors, whereas %EE, cumulative drug release (%CDR), and particle size were selected as dependent variables. Interactions between drug substances and polymers were studied using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and atomic force microscopy (AFM) analysis indicated the crystalline change from the drug to the amorphous crystal. Electron microscope studies revealed that the SLNs&rsquo; structure is nearly perfectly round. It is evident from the findings that dapagliflozin-SLNs could lower elevated blood glucose levels to normal in STZ-induced diabetic rats, demonstrating a better hypoglycemic impact on type 2 diabetic patients. The in vivo pharmacokinetic parameters of SLNs exhibited a significant rise in Cmax (1258.37 &plusmn; 1.21 mcg/mL), AUC (5247.04 mcg/mL), and oral absorption (2-fold) of the drug compared to the marketed formulation in the Sprague Dawley rats
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