19672 research outputs found
Sort by
Characterization and potential roles of bone marrow-derived stromal cells in cancer development and metastasis
Get PDFBackground: The tumor microenvironment and its stromal cells play an important role in cancer development and metastasis. Bone marrow-derived cells (BMDCs), a rich source of hematopoietic and mesenchymal stem cells, putatively contribute to this tumoral stroma. However their characteristics and roles within the tumor microenvironment are unclear. In the present study, BMDCs in the tumor microenvironment were traced using the green fluorescent protein (GFP) bone marrow transplantation model. Methods: C57BL/6 mice were irradiated and rescued by bone marrow transplantation from GFP-transgenic mice. Lewis lung cancer cells were inoculated into the mice to generate subcutaneous allograft tumors or lung metastases. Confocal microscopy, immunohistochemistry for GFP, alpha-SMA, CD11b, CD31, CD34 and CD105, and double-fluorescent immunohistochemistry for GFP-CD11b, GFP-CD105 and GFP-CD31 were performed. Results: Round and dendritic-shaped GFP-positive mononuclear cells constituted a significant stromal subpopulation in primary tumor peripheral area (PA) and metastatic tumor area (MA) microenvironment, thus implicating an invasive and metastatic role for these cells. CD11b co-expression in GFP-positive cells suggests that round/dendritic cell subpopulations are possibly BM-derived macrophages. Identification of GFP-positive mononuclear infiltrates co-expressing CD31 suggests that these cells might be BM-derived angioblasts, whereas their non-reactivity for CD34, CD105 and alpha-SMA implies an altered vascular phenotype distinct from endothelial cells. Significant upregulation of GFP-positive, CD31-positive and GFP/CD31 double-positive cell densities positively correlated with PA and MA (P<0.05). Conclusion: Taken together, in vivo evidence of traceable GFP-positive BMDCs in primary and metastatic tumor microenvironment suggests that recruited BMDCs might partake in cancer invasion and metastasis, possess multilineage potency and promote angiogenesis
Sugar consumption and caries occurrence among Pakistani school children
Get PDFObjectives: To estimate the frequency and pattern of sugar intake among Pakistani school going children and its association with early carious lesion and caries history. Methods: The cross-sectional study was conducted from January to May 2016 in seven schools of Bhakkar district in the Punjab province of Pakistan, and comprised of school children aged 11-12 years. Diet diaries were used to assess the frequency of sugar intake while caries was assessed using the Modified International Caries Detection and Assessment System. Bivariate analysis was used to assess the association of sugar consumption and early carious lesion with selected sociodemographic variables, and regression analysis was performed to evaluate the factor that matters most in caries occurrence. Results: Of the 226 subjects, 115(51%) had early carious lesion. Mean frequency of sugar intake was 5.2 +/- 3.2 times per day. Children who consumed sugar between main meals (p=0.01) and within two hours before bedtime (p=0.04) had significantly higher history of having caries. Cariogenic intake before bedtime was significantly associated with overall caries risk (p=0.02). Conclusion: The frequency of sugar intake among the subjects was slightly higher than the recommended level
Energy harvesting for efficient 5G networks
Get PDFThe design of traditional mobile wireless network emphasises on large capacity as well as ubiquitous access. However, environmental protection and energy saving may soon become inevitable trends due to rising global demands. In the wireless networking field, researchers should shift their focus towards efficient networks and energy harvesting (EH). In this work, we consider energy efficiency and EH to address the issue of energy shortage, which also represents the ratio of the quantity of data that have been transferred to the dissipated energy within the system, simultaneously. The simulation-based mathematics signifies the relation between energy efficiency
Taghyir khalqillah dan transplan anggota badan atau organ: Analisis terhadap resolusi dan fatwa badan fatwa terpilih
Get PDFPara saintis sentiasa cuba meningkatkan perkhidmatan rawatan mereka kepada para pesakit melalui pelbagai cara. Antara rawatan terpenting yang pernah ditawarkan dalam sejarah perubatan adalah rawatan transplan anggota badan dan organ manusia yang mampu menyelamatkan nyawa pesakit. Pelbagai organ yang boleh dilakukan proses transplantasi bermula dari anggota badan yang ringkas seperti gigi, tulang dan kulit sehinggalah ke organ yang kompleks seperti mata, buah pinggang, jantung dan rahim. Malah, pada awal tahun 2018, seorang professor Itali bernama Canavero cuba melakukan transplan kepala di China (https://www.sde.co.ke/article/2001266397/world-s-first-human-head-transplant-successfully-carried-out).
Transplan kepala ini boleh dianggap sebagai proses transplan paling rumit kerana melibatkan organ yang paling banyak sel saraf dan sel darah. Pada hari ini, kebanyakan badan fatwa utama dunia telah mengharuskan transplan organ kerana ia memberikan pelbagai manfaat kepada manusia. Namun, menelusuri sejarah hukum mengenai transplan organ, tidak semua ulama bersetuju dengan prosedur ini dengan alasan prosedur ini mengubah ciptaan Allah SWT (taghyir khalqillah), manusia tiada hak ke atas tubuh badan sendiri sehingga membenarkan mereka menderma organ mereka dan prosedur ini menyebabkan pencemaran pada kehormatan manusia (http://alchourouk.co- - - - m/157389/687/ اختلففف الفقهففف فففف التبّففف / 1
ب لأعض بين الح مة والإب حة - - - -.html)
Fiber density of collagen grafts impacts rabbit urethral regeneration
Get PDFThere is a need for efficient and "off-The-shelf" grafts in urethral reconstructive surgery. Currently available surgical techniques require harvesting of grafts from autologous sites, with increased risk of surgical complications and added patient discomfort. Therefore, a cost-effective and cell-free graft with adequate regenerative potential has a great chance to be translated into clinical practice. Tubular cell-free collagen grafts were prepared by varying the collagen density and fiber distribution, thereby creating a polarized low fiber density collagen graft (LD-graft). A uniform, high fiber density collagen graft (HD-graft) was engineered as a control. These two grafts were implanted to bridge a 2 cm long iatrogenic urethral defect in a rabbit model. Histology revealed that rabbits implanted with the LD-graft had a better smooth muscle regeneration compared to the HD-graft. The overall functional outcome assessed by contrast voiding cystourethrography showed patency of the urethra in 90% for the LD-graft and in 66.6% for the HD-graft. Functional regeneration of the rabbit implanted with the LD-graft could further be demonstrated by successful mating, resulting in healthy offspring. In conclusion, cell-free low-density polarized collagen grafts show better urethral regeneration than high-density collagen grafts
Synthesis of selected pyrazine derivatives and their photopyhsical characteristics
Get PDF2-Phenoxypyrazine, 2-o-methyphenoxypyrazine, 2-m-methylphenoxypyrazine, and 2-p-methylphenoxypyrazine were obtained when 2-chloropyrazine was treated with phenol, o-cresol, m-cresol and p-cresol respectively. Reactions of 2-choropyrazine-5-carboxylic acid methyl ester with phenol, 3-methylphenol and 3-nitrophenol gave 5-phenoxypyrazine- 2-carboxylic acid, 5-m-tolyoxyprazine-2-carboxyclic acid methyl ester and 5-(-3-nitrophenoxy) pyrazine-2-carboxyliic acid methyl ester respectively. 2.5-Dimethyl-3-phenoxypyrazine was obtained when phenol was reacted with 3-chloro- 2,5-dimethylpyrazine. Naphthalenyloxy derivatives were obtained when 2- chloropyrazine reacted with 1 and 2- naphtol respectively. The structures of newly synthesized compounds were spectroscopically characterized. Fluorescence studies showed that compounds 2, 4 and 8 quenched in the presence of oxygen. Compounds 1 and 7 showed the highest fluorescence intensity in alkaline condition. Compound 1, 4 and 8 exhibit the highest emission wavelength in non-polar solvents and falls drastically in polar aprotic solvents. Highest fluorescence intensity was recorded with compounds which have electron donating substituents and has rigid structure
Performance and emission opacity of canola and soybean biodiesel fuel in a diesel engine
No full textBiodiesel is a renewable fuel known to produce more environmentally friendly emissions compared to diesel fuel. However, at times it has been reported as exhibiting a much lower engine performance compared to standard diesel fuel. Biodiesel fuel has the potential to achieve similar performance as compared to diesel fuel when the optimum percentage of biodiesel blend is used. In this study, an experiment was conducted to determine the performance and opacity of emissions collected from soybean biodiesel and canola biodiesel fuel by using a YANMAR TF90 single cylinder direct injection diesel engine. The objective of this study is to determine the best percentage of diesel-soybean and diesel-canola fuel mixture that would result in the best performance of an engine. The experiment investigated the brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), brake power (BP), and torque generated by the engine using different biodiesel fuel percentages at varying engine speeds. Additionally, the emission opacity was investigated to identify the most favourable fuel percentage for optimised biodiesel compared to the quality obtained from soybean and canola soybean biodiesel. The results from the experiment clearly show that the engine using biodiesel fuel has a slightly lower performance as compared to the engine that only used diesel fuel for all percentages used. However, at low speeds, a BTE of 40% canola biodiesel was higher compared to diesel and soybean biodiesel. The BSFC for all biodiesel fuel was found to be slightly higher than diesel, except for BC40, which was greater for BSFC compared to other blends used at much lower engine speeds. Engine emission opacity of biodiesel was recorded to be less than diesel fuel at all engine speeds, but slightly higher for BC5, BS5 and BS20 due to the insufficient air intake to the engine. Engine performance and emission opacity of all biodiesel fuels were found to be similar to diesel fuel. From the results relating to engine performance and emission, canola biodiesel was found to be an excellent biodiesel product to be used in a diesel engine since it had a higher BTE, lower BSFC and a lower opacity which was greater than those of soybean biodiesel blends. Therefore, biodiesel can be blended in a diesel engine at a higher percentage while maintaining engine performance and reducing engine emission
Influence of Hydrophobicity of Acetylated Nanocellulose on the Mechanical Performance of Nitrile Butadiene Rubber (NBR) Composites
No full textNovel acetylation process by substitution of acetic anhydride substitution with hydroxyl groups on nanocellulose (NCC) has been explored to increase its dispersion and interaction in nitrile butadiene (NBR) matrix. The crystallinity index was increased after modification when compared to unmodified NCC, but no significant different with increases of treatment time from 1 hour to 3 hours treatments proven by X-ray diffraction (XRD) results. The Fourier transform infra-red (FTIR) showed the existent of acetyl groups on surface of the NCC after treatment by existent of the peak 1736 cm-1 that attributed to carbonyl groups some peaks were observed at 1430, 1361 and 1248 cm-1 and confirmed on the acetylation process. The nuclear magnetic resonance (NMR) also show the present of acetyl groups by existent of the signal of proton methyl group at 1.90 ppm and new peaks at 5.42, 4.70 and 4.34 ppm, for all ACN samples. The thermal results by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that the acetylated NCCs were 10 % more thermally stable. Transmission electron microscopic (TEM) results showed that no significant changes were observed due to the acetylation process. The results also showed well distributed of individual NCC after acetylation, this improvement was primarily attributed to uniform dispersion of the ACN-NCC and less aggregated occurred. Due to its hydrophobic characteristics, highly crystalline and nano size, ACN-NCC brought a significant improvement up to 25 % on the mechanical properties of nitrile butadiene (NBR) rubber composites
Empirical model for Darrieus-type tidal current turbine induced seabed scour
No full textTidal current turbine has attracted many attentions, but the impact of Darrieus-type tidal current turbine on the seabed scour process still remains unclear. This work aims to propose an empirical model, which can be used to predict the maximum scour depth against different tip clearance and rotor radius. The study also presents the scour profiles along centreline of turbine by using the proposed empirical equations. A series of three-dimensional printed turbine models were placed in a circulating water flume to investigate the scour profiles. The results suggest that the scour depth increases with the decrease of tip clearance. When the turbine is installed very close to seabed, the scour process is live bed scour with the collapse of the slant bed. Under this kind of condition, the maximum scour depth will not further increase with the continuous decrease of tip clearance. The current experimental results propose that the maximum scour depth is about 80% deeper than scour depth around single pile. The maximum scour depth increases firstly and then decreases with the increase of rotor radius. Based on experimental results, an empirical model of Darrieus-type tidal current turbine induced seabed scour is proposed to predict the maximum scour depth and scour profiles along centreline of turbine
Novel multiplex PCR-RFLP assay discriminates bovine, porcine and fish gelatin substitution in Asian pharmaceuticals capsule shells
No full textGelatin is widely used in pharmaceuticals as a protective coating, such as soft and hard capsule shells. However, the animal source of gelatin is a sensitive issue because certain gelatins such as porcine and bovine gelatins are not welcome in Halal, Kosher and Hindus’ consumer goods. Recently, we have documented DNA barcoding and multiplex PCR platforms for discriminating porcine, bovine and fish gelatins in various fish and confectionary products; but those assays were not self-authenticating and also not tested in highly refined pharmaceutical products. To address this knowledge gap, here we report a self-authenticating multiplex PCR-restriction fragment length polymorphism (RFLP) assay to identify animal sources of various gelatin in pharmaceutical capsules. Three different restriction enzymes, BsaAI, Hpy188I and BcoDI were used to yield distinctive RFLP patterns for gelatin-based bovine (26, 94 bp), fish (97, 198 bp) and porcine (17, 70 bp) DNA in control experiments. The specificity was cross-tested against 16 non-target species and the optimised assay was used to screen gelatin sources in 30 halal-branded pharmaceuticals capsule shells. Bovine and porcine DNA was found in 27 and 3 of the 30 different capsules products. The assay was suitable for detecting 0.1 to 0.01 ng total DNA extracted from pure and mixed gelatins. The study might be useful to authenticate and monitor halal, kosher, vegetarian and Hindu compliant pharmaceuticals, foods and cosmetics