Duodenal prostaglandin synthesis and acid load in health and in duodenal ulcer disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahlquist, D.A.; Dozois, R.R.; Zinsmeister, A.R.

1983-09-01

We sought to test the hypothesis that duodenal ulcer disease results from an imbalance between duodenal acid load, an injurious force, and mucosal prostaglandin generation, a protective factor. Ten patients with duodenal ulcer and 8 healthy controls were studied. The duodenal acid load after an amino acid soup was quantified by a double-marker technique. Mucosal biopsy specimens were taken endoscopically from the duodenal bulb before and after the test meal. Prostaglandin synthesis activity was measured by incubating biopsy homogenates in excess (/sup 14/C)arachidonic acid. Although mean duodenal acid load was higher in duodenal ulcer, ranges overlapped. Neither the qualitative normore » quantitative profile of mucosal prostaglandin synthesis activities differed significantly between test groups. Prostaglandin synthesis activities, however, tended to increase post cibum in controls, but change little or decrease in duodenal ulcer. Only by comparing the responses with a meal of both parameters together (duodenal acid load and the change in prostaglandin synthesis activities) was there complete or nearly complete separation of duodenal ulcer from controls. Greatest discrimination was observed with prostacyclin (6-keto-PGF1 alpha). We conclude that in health, mucosal prostaglandin generation in the duodenum is induced post cibum in relation to duodenal acid load; this may be a physiologic example of adaptive cytoprotection. In duodenal ulcer there may be a defect in such a mechanism.« less

Development of smart delivery system for ascorbic acid using pH-responsive P(MAA-co-EGMA) hydrogel microparticles.

PubMed

Lee, Eunmi; Kim, Kyusik; Choi, Moonjae; Lee, Youngmoo; Park, Jin-Won; Kim, Bumsang

2010-11-01

pH-Responsive P(MAA-co-EGMA) hydrogel microparticles were prepared and their feasibility as intelligent delivery carriers was evaluated. P(MAA-co-EGMA) hydrogel microparticles were synthesized via dispersion photopolymerization. There was a drastic change in the swelling ratio of P(MAA-co-EGMA) microparticles at a pH of ~ 5 and, as the amount of MAA in the hydrogel increased, the swelling ratio increased at a pH above 5. The loading efficiency of the ascorbic acid into the hydrogel was affected more by the degree of swelling of the hydrogel than the electrostatic interaction between the hydrogel and the loaded ascorbic acid. The P(MAA-co-EGMA) hydrogel microparticles showed a pH-sensitive release behavior. Thus, at pH 4 almost none of the ascorbic acid permeated through the skin while at pH 6 relatively high skin permeability was obtained. The ascorbic acid loaded in the hydrogel particles was hardly degraded and its stability was maintained at high temperature.

Effect of palmitic acid on the characteristics and release profiles of rotigotine-loaded microspheres.

PubMed

Wang, Aiping; Liang, Rongcai; Liu, Wanhui; Sha, Chunjie; Li, Youxin; Sun, Kaoxiang

2016-01-01

The initial burst release is a major obstacle to the development of microsphere-formulated drug products. To investigate the influence of palmitic acid on the characteristics and release profiles of rotigotine-loaded poly(d,l-lactide-co-glycolide) microspheres. Rotigotine-loaded microspheres (RMS) were prepared using the oil-in-water emulsion solvent evaporation technique. The in vitro characteristics of the RMS were evaluated with scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and a particle size analyzer. The in vitro drug release and in vivo pharmacokinetics of the RMS were investigated. The SEM results showed that the addition of palmitic acid changed the surface morphology of the microspheres from smooth to dimpled and then to non-smooth as the palmitic acid content increased. DSC revealed the existence of molecularly dispersed forms of palmitic acid in the microspheres. The in vitro and in vivo release profiles indicated that the addition of 5% and 8% palmitic acid significantly decreased the burst release of rotigotine from the microspheres, and the late-stage release was delayed as the palmitic acid content increased across the investigated range (5-15%). The addition of palmitic acid to the microspheres significantly affects the release profile of rotigotine from RMS.

Synthesis and characterization of 12-aminolauric acid-modified montmorillonite for catalytic application

NASA Astrophysics Data System (ADS)

Pagtalunan, Cris Angelo M.; Sumera, Florentino C.; Conato, Marlon T.

2018-05-01

The simple cation-exchange preparation of 12-aminolauric acid-modified montmorillonite (ALA-Mt), an aluminosilicate clay modified with the alkylammonium surfactant, is reported. Different loadings of 12-aminolauric acid (12-ALA) from 100 to 400 times the cation exchange capacity (CEC) in montmorillonite (Mt) was prepared and studied. Successful intercalation of the organic surfactant was monitored by the increase in basal (d001) spacing of the organoclay compared to the pure Mt. The clay mineral composite have increased surfactant loading resulting to lower degradation temperatures, rougher surface morphology, increased particle size, and increased organophilicity of the organoclay compared to the native Mt. The improved properties of ALA-Mt present it as an attractive catalyst material for polymerization reactions.

Higher Estimated Net Endogenous Acid Production May Be Associated with Increased Prevalence of Nonalcoholic Fatty Liver Disease in Chinese Adults in Hong Kong

PubMed Central

Chan, Ruth; Wong, Vincent Wai-Sun; Chu, Winnie Chiu-Wing; Wong, Grace Lai-Hung; Li, Liz Sin; Leung, Jason; Chim, Angel Mei-Ling; Yeung, David Ka-Wai; Sea, Mandy Man-Mei; Woo, Jean; Chan, Francis Ka-Leung; Chan, Henry Lik-Yuen

2015-01-01

Nonalcoholic fatty liver disease (NAFLD) has been associated with reduced growth hormone levels and signaling. Such hormonal changes also occur in metabolic acidosis. Since mild metabolic acidosis can be diet induced, diet-induced acid load may constitute a nutritional factor with possible influence on NAFLD development. This study explored whether a higher diet-induced acid load is associated with an increased likelihood of NAFLD. Apparently healthy Chinese adults (330 male, 463 female) aged 19-72 years were recruited through population screening between 2008 and 2010 in a cross-sectional population-based study in Hong Kong. Estimated net endogenous acid production (NEAP) was calculated using Frassetto’s method and potential renal acid load (PRAL) was calculated using Remer’s method based on dietary data from a food frequency questionnaire. NAFLD was defined as intrahepatic triglyceride content at >5% by proton-magnetic resonance spectroscopy. Possible advanced fibrosis was defined as liver stiffness at >7.9 kPa by transient elastography. Multivariate logistic regression models were used to examine the association between each measure of dietary acid load and prevalent NAFLD or possible advanced fibrosis with adjustment for potential anthropometric and lifestyle factors. 220 subjects (27.7%) were diagnosed with NAFLD. Estimated NEAP was positively associated with the likelihood of having NAFLD after adjustment for age, sex, body mass index, current drinker status and the presence of metabolic syndrome [OR (95% CI) = 1.25 (1.02-1.52), p = 0.022]. The association was slightly attenuated but remained significant when the model was further adjusted for other dietary variables. No association between PRAL and NAFLD prevalence was observed. Both estimated NEAP and PRAL were not associated with the presence of possible advance fibrosis. Our findings suggest that there may be a modest association between diet-induced acid load and NAFLD. More studies are needed to ascertain the link between diet-induced acid load and NAFLD and to investigate the underlying mechanisms. PMID:25905490

Potential differentiation ability of gingiva originated human mesenchymal stem cell in the presence of tacrolimus

PubMed Central

Ha, Dong-Ho; Pathak, Shiva; Yong, Chul Soon; Kim, Jong Oh; Jeong, Jee-Heon; Park, Jun-Beom

2016-01-01

The aim of the present study is to evaluate the potential differentiation ability of gingiva originated human mesenchymal stem cell in the presence of tacrolimus. Tacrolimus-loaded poly(lactic-co-glycolic acid) microspheres were prepared using electrospraying technique. In vitro release study of tacrolimus-loaded poly(lactic-co-glycolic acid) microspheres was performed in phosphate-buffered saline (pH 7.4). Gingiva-derived stem cells were isolated and incubated with tacrolimus or tacrolimus-loaded microspheres. Release study of the microspheres revealed prolonged release profiles of tacrolimus without any significant initial burst release. The microsphere itself did not affect the morphology of the mesenchymal stem cells, and cell morphology was retained after incubation with microspheres loaded with tacrolimus at 1 μg/mL to 10 μg/mL. Cultures grown in the presence of microspheres loaded with tacrolimus at 1 μg/mL showed the highest mineralization. Alkaline phosphatase activity increased with an increase in incubation time. The highest expression of pSmad1/5 was achieved in the group receiving tacrolimus 0.1 μg/mL every third day, and the highest expression of osteocalcin was achieved in the group receiving 1 μg/mL every third day. Biodegradable poly(lactic-co-glycolic acid)-based microspheres loaded with tacrolimus promoted mineralization. Microspheres loaded with tacrolimus may be applied for increased osteoblastic differentiation. PMID:27721434

Oleic Acid enhances all-trans retinoic Acid loading in nano-lipid emulsions.

PubMed

Chinsriwongkul, Akhayachatra; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Sila-On, Warisada; Ruktanonchai, Uracha

2010-01-01

The aim of this study was to investigate the enhancement of all-trans retinoic acid (ATRA) loading in nano-lipid emulsions and stability by using oleic acid. The effect of formulation factors including initial ATRA concentration and the type of oil on the physicochemical properties, that is, percentage yield, percentage drug release, and photostability of formulations, was determined. The solubility of ATRA was increased in the order of oleic acid > MCT > soybean oil > water. The physicochemical properties of ATRA-loaded lipid emulsion, including mean particle diameter and zeta potential, were modulated by changing an initial ATRA concentration as well as the type and mixing ratio of oil and oleic acid as an oil phase. The particles of lipid emulsions had average sizes of less than 250 nm and negative zeta potential. The addition of oleic acid in lipid emulsions resulted in high loading capacity. The photodegradation rate was found to be dependent on the initial drug concentration but independent of the type of oily phase used in this study. The release rates were not affected by initial ATRA concentration but were affected by the type of oil, where oleic acid showed the highest release rate of ATRA from lipid emulsions.

Functional and in vitro gastric digestibility of the whey protein hydrogel loaded with nanostructured lipid carriers and gelled via citric acid-mediated crosslinking.

PubMed

Hashemi, Behnaz; Madadlou, Ashkan; Salami, Maryam

2017-12-15

Nanostructured lipid carriers (NLCs) with mean size of 347nm were fabricated and added into a heat-denatured whey protein solution. The subsequent crosslinking of proteins by citric acid or CaCl 2 resulted in the formation of cold-set hydrogels. Fourier transform infrared spectroscopy (FTIR) proposed formation of more hydrogen bonds in gel due to NLC loading or citric acid-mediated gelation. It was also found based on FITR spectroscopy that citric acid crosslinking disordered whey proteins. Scanning electron microscopy (SEM) imaging showed a non-porous and finely meshed microstructure for the crosslinked gels compared to non-crosslinked counterparts. Crosslinking also increased the firmness and water-holding capacity of gels. In pepsin-free fluid, a strong correlation existed between reduction in gel swellability and digestibility over periods up to 60min due to NLC loading and citric acid gelation. However, in peptic fluid, NLC loading and citric acid crosslinking brought about much higher decrease in digestibility than swellability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of household cooking techniques on the microbiological load and the nutritional quality of mealworms (Tenebrio molitor L. 1758).

PubMed

Caparros Megido, Rudy; Poelaert, Christine; Ernens, Marjorie; Liotta, Marisa; Blecker, Christophe; Danthine, Sabine; Tyteca, Eva; Haubruge, Éric; Alabi, Taofic; Bindelle, Jérôme; Francis, Frédéric

2018-04-01

Mealworms are new food products in Europe, but consumers do not know how to cook them. Although cooking could increase the safety, acceptability, palatability, and digestibility of insects, the heating process could have deleterious effects on protein and lipid quality. Therefore, this study characterized the effects of different household cooking methods (boiling, pan-frying, vacuum cooking, and oven cooking) on the microbial load and nutritive value of mealworms, with a focus on protein digestibility and fatty acid composition. Boiling and cooking under vacuum were the most efficient techniques to reduce microbial load while maintaining the high levels of protein and polyunsaturated fatty acids of mealworms. Cooking method-related changes were very low on macronutrients content except for pan-fried mealworms which exhibited the highest lipid content. Cooking slightly changed fatty acid composition of mealworms by principally decreasing their level of saturated fatty acids but also increased the in vitro crude protein digestibility of mealworms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Lipid-drug-conjugate (LDC) solid lipid nanoparticles (SLN) for the delivery of nicotine to the oral cavity - optimization of nicotine loading efficiency.

PubMed

Ding, Yuan; Nielsen, Kent A; Nielsen, Bruno P; Bøje, Niels W; Müller, Rainer H; Pyo, Sung Min

2018-03-12

Nicotine, obtained from tobacco leaves, has been used to promote the cessation of smoking and reduce the risk of COPD and lung cancer. Incorporating the active in lipid nanoparticles is an effective tool to minimize its irritation potential and to use the particles as intermediate to produce final products. However, as a hydrophilic active, it is a challenge to prepare nicotine loaded lipid nanoparticles with high drug loading. In this study, lipid-drug-conjugates (LDC) were formed by nicotine and different fatty acids to enable the production of sufficiently loaded nicotine lipid nanoparticles. The encapsulation efficiency of nicotine in LDC-containing SLN was about 50%, which increased at least fourfold compared to the non-LDC formulations (around 10%) due to the increased lipophilicity of nicotine by strong interactions between positively charged nicotine and negatively charged fatty acids (formation of LDCs). The z-average of all formulations (150 to 350 nm) proved to be in the required submicron size range with a narrow size distribution. In summary, nicotine loaded LDC lipid nanoparticles with high drug loading were successfully developed with Kolliwax® S and stearic acid as counter-ion forming the LDC and hydrogenated sunflower oil (HSO) as lipid particle matrix. Copyright © 2018. Published by Elsevier B.V.

Dietary Acid Load and Incident Chronic Kidney Disease: Results from the ARIC Study

PubMed Central

Rebholz, Casey M.; Coresh, Josef; Grams, Morgan E.; Steffen, Lyn M.; Anderson, Cheryl A.M.; Appel, Lawrence J.; Crews, Deidra C.

2016-01-01

Background Higher dietary acid load can result in metabolic acidosis and is associated with faster kidney disease progression in patients with chronic kidney disease (CKD). However, the relationship between dietary acid load and incident CKD has not been evaluated. Methods We conducted prospective analyses of Atherosclerosis Risk in Communities study participants without CKD at baseline (1987–89, N=15,055). Dietary acid load was estimated using the equation for potential renal acid load by Remer and Manz, incorporating dietary intake data from a food frequency questionnaire. Incident CKD was assessed from baseline through 2010 and defined as eGFR <60 mL/min/1.73 m2 accompanied by 25% eGFR decline, CKD-related hospitalization or death, or end-stage renal disease identified by linkage to the U.S. Renal Data System registry. Results In the overall study population, 55% were female, 26% were African-American, and mean age at baseline was 54 years. During a median follow-up of 21 years, there were 2,351 (15.6%) incident CKD cases. After adjusting for demographics (age, sex, race-center), established risk factors (diabetes status, hypertension status, overweight/obese status, smoking status, education level, physical activity), caloric intake, and baseline eGFR, higher dietary acid load was associated with higher risk of incident CKD [hazard ratio (HR) for quartile 4 vs. 1: 1.13, 95% confidence interval (CI): 1.01, 1.28, p for trend=0.02; HR per interquartile range increase: 1.06, 95% CI: 1.00, 1.11, p=0.04]. Conclusion Dietary acid load is associated with incident CKD in a population-based sample. These data suggest a potential avenue for CKD risk reduction through diet. PMID:26789417

Lactic acid production from Sophora flavescens residues pretreated with sodium hydroxide: Reutilization of the pretreated liquor during fermentation.

PubMed

Wang, Juan; Gao, Ming; Liu, Jianguo; Wang, Qunhui; Wang, Cong; Yin, Zihe; Wu, Chuanfu

2017-10-01

The feasibility of lactic acid production from Sophora flavescens residues (SFRs) pretreated with sodium hydroxide with the reutilization of the pretreated liquor during fermentation was investigated. After sodium hydroxide pretreatment, 67.5% of the lignin was removed, and hydrolysis efficiency increased from 37.3% to 79.2%. The reutilization of pretreated liquor at 50% loading during open fermentation of unwashed SFR increased lactic acid production by 34.1%. The pretreated liquor acted as pH buffer and resulted in stable pH and high cellulase activity during fermentation. Inhibitors in the pretreated liquor did not affect the growth of lactic acid bacteria but severely inhibited the growth of ethanol-producing yeast. Consequently, lactic acid production increased and ethanol production was zero at 50% loading. Water consumption during pretreatment and fermentation with 50% pretreated liquor was 1.341L per 100g SFR, which was 67.6% lower than that during fermentation with washed SFR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dietary protein, calcium metabolism and bone health in humans

USDA-ARS?s Scientific Manuscript database

Protein is the major structural constituent of bone (50% by volume). But it is also a major source of metabolic acid, especially protein from animal sources because it contains sulfur amino acids that generate sulfuric acid. Increased potential renal acid load has been closely associated with increa...

Omega-3 Fatty Acid Docosahexaenoic Acid Increases SorLA/LR11, a Sorting Protein with Reduced Expression in Sporadic Alzheimer’s Disease (AD): Relevance to AD Prevention

PubMed Central

Ma, Qiu-Lan; Teter, Bruce; Ubeda, Oliver J.; Morihara, Takashi; Dhoot, Dilsher; Nyby, Michael D.; Tuck, Michael L.; Frautschy, Sally A.; Cole, Greg M.

2008-01-01

Environmental and genetic factors, notably ApoE4, contribute to the etiology of late-onset Alzheimer’s disease (LOAD). Reduced mRNA and protein for an apolipoprotein E (ApoE) receptor family member, SorLA (LR11) has been found in LOAD but not early-onset AD, suggesting that LR11 loss is not secondary to pathology. LR11 is a neuronal sorting protein that reduces amyloid precursor protein (APP) trafficking to secretases that generate β-amyloid (Aβ). Genetic polymorphisms that reduce LR11 expression are associated with increased AD risk. However these polymorphisms account for only a fraction of cases with LR11 deficits, suggesting involvement of environmental factors. Because lipoprotein receptors are typically lipid-regulated, we postulated that LR11 is regulated by docosahexaenoic acid (DHA), an essential ω-3 fatty acid related to reduced AD risk and reduced Aβ accumulation. In this study, we report that DHA significantly increases LR11 in multiple systems, including primary rat neurons, aged non-Tg mice and an aged DHA-depleted APPsw AD mouse model. DHA also increased LR11 in a human neuronal line. In vivo elevation of LR11 was also observed with dietary fish oil in young rats with insulin resistance, a model for type II diabetes, another AD risk factor. These data argue that DHA induction of LR11 does not require DHA-depleting diets and is not age dependent. Because reduced LR11 is known to increase Aβ production and may be a significant genetic cause of LOAD, our results indicate that DHA increases in SorLA/LR11 levels may play an important role in preventing LOAD. PMID:18160637

Ascorbic acid prevents vascular dysfunction induced by oral glucose load in healthy subjects.

PubMed

De Marchi, Sergio; Prior, Manlio; Rigoni, Anna; Zecchetto, Sara; Rulfo, Fanny; Arosio, Enrico

2012-01-01

To examine the effects of oral glucose load on forearm circulatory regulation before and after ascorbic acid administration in healthy subjects. Microcirculation study with laser Doppler was performed at the hand in basal conditions, after ischemia and after acetylcholine and nitroprusside; strain gauge plethysmography was performed at basal and after ischemia. The tests were repeated in the same sequence 2 hour after oral administration of glucose (75 g). The subjects were randomised for administration of ascorbic acid (1 g bid) or placebo (sodium bicarbonate 1 g bid) for 10 days. After that, the tests were repeated before and after a new oral glucose load. Blood pressure and heart rate were monitored. Macrocirculatory flux, pressure values and heart rate were unvaried throughout the study. The glucose load caused a reduction in the hyperemic peak flow with laser Doppler and plethysmography; it reduced flux recovery time and hyperemic curve area after ischemia; acetylcholine elicited a minor increase in flux with laser Doppler. The response to nitroprusside was unvaried after glucose load as compared to basal conditions. Treatment with ascorbic acid prevented the decrease in hyperemia after glucose, detected with laser Doppler and plethysmography. Ascorbic acid prevented the decreased response to acetylcholine after glucose, the response to nitroprusside was unaffected by ascorbic acid. Results after placebo were unvaried. Oral glucose load impairs endothelium dependent dilation and hyperaemia at microcirculation, probably via oxidative stress; ascorbic acid can prevent it. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Biochemical profile of Achatina fulica (Mollusca: Gastropoda) after infection by different parasitic loads of Angiostrongylus cantonensis (Nematoda, Metastrongylidae).

PubMed

Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Amaral, Ludimila Santos; Mota, Esther Maria; Maldonado Júnior, Arnaldo; Pinheiro, Jairo; Garcia, Juberlan

2015-01-01

The effect of experimental infection by different parasitic loads of Angiostrongylus cantonensis (Nematode, Metastrongylidae) on the activities of the aminotransferases and concentration of total proteins, uric acid and urea in the hemolymph of Achatina fulica (Mollusca, Gastropoda) were investigated. There was a significant decrease in the concentration of total proteins in the exposed snails to 5000 or more larvae. This change was accompanied by an increase in the concentrations of urea and uric acid in the hemolymph, suggesting a higher rate of deamination of the amino acids. Besides this, variations in the activities of the aminotransferases were also observed, with the highest values recorded in the groups exposed to greater parasite load. These results suggest an increase in the use of total proteins, since there was increased formation of nitrogenous catabolites, in conformity with an increase in the aminotransferase activities. Infection was verified by the fact that L3 larvae recovered from the snails was proportion to the exposure dose of L1 larvae. Histopathological results also indicated presence of an inflammatory cell infiltrate, favoring an increase of both transaminases. Copyright © 2014 Elsevier Inc. All rights reserved.

Olive oil increases the magnitude of postprandial chylomicron remnants compared to milk fat and safflower oil.

PubMed

Higashi, K; Ishikawa, T; Shige, H; Tomiyasu, K; Yoshida, H; Ito, T; Nakajima, K; Yonemura, A; Sawada, S; Nakamura, H

1997-10-01

The acute effects of olive oil, milk fat and safflower oil on postprandial lipemia and remnant lipoprotein metabolism were investigated. Eight Healthy male volunteers randomly underwent three types of oral fat-vitamin A loading tests. The test drink was a mixture of retinyl palmitate (RP)(50,000 IU of aqueous vitamin A/m2 body surface area) and one of the three types of oils (40 g of fat/m2 body surface area): olive oil (70.7% oleic acid of total fatty acids); milk fat (69.3% saturated fatty acid); safflower oil (74.2% linoleic acid). Olive oil significantly increased plasma triacylglycerol and RP concentrations 4 hours after fat loading, as compared to other fats. Increases of remnant like particle concentrations were higher after olive oil than after the other two fats. These results show that olive oil increases the magnitude of postprandial chylomicrons and chylomicron remnants compared to milk fat and safflower oil.

Characterization of selectively etched halloysite nanotubes by acid treatment

NASA Astrophysics Data System (ADS)

Garcia-Garcia, Daniel; Ferri, Jose M.; Ripoll, Laura; Hidalgo, Montserrat; Lopez-Martinez, Juan; Balart, Rafael

2017-11-01

Halloysite nanotubes (HNTs) are a type of naturally occurring inorganic nanotubes that are characterized by a different composition between their external and internal walls. The internal walls are mainly composed of alumina whilst external walls are composed of silica. This particular structure offers a dual surface chemistry that allows different selective surface treatments which can be focused on increasing the lumen, increasing porosity, etc. In this work, HNTs were chemically treated with different acids (sulphuric, acetic and acrylic acid), for 72 h at a constant temperature of 50 °C. As per the obtained results, the treatment with sulphuric acid is highly aggressive and the particular shape of HNTs is almost lost, with a remarkable increase in porosity. The BET surface area increases from 52.9 (untreated HNTs) up to 132.4 m2 g-1 with sulphuric acid treatment, thus showing an interesting potential in the field of catalysis. On the other hand, the treatment with acetic acid led to milder effects with a noticeable increase in the lumen diameter that changed from 13.8 nm (untreated HNTs) up to 18.4 nm which the subsequent increase in the loading capacity by 77.8%. The aluminium content was measured by X-ray fluorescence (XRF) and laser induced breakdown spectroscopy (LIBS). The final results using two systems, suggest a good correlation between the acid strength and the aluminium reduction. Consequently, is possible to conclude that new applications for HNTs can be derived from selective etching with acids. Sulphuric acid widens the potential of HNTs in the field of catalysis while weak acids such as acetic and acrylic acids give a controlled and homogeneous lumen increase with the corresponding increase in the loading capacity.

Reduction of Dietary Acid Load as a Potential Countermeasure for Bone Loss Associated with Spaceflight

NASA Technical Reports Server (NTRS)

Zwart, S. R.; Watts, S. M.; Sams, C. F.; Whitson, P. A.; Smith, S. M.

2006-01-01

In several studies we tested the concepts that diet can alter acid-base balance and that reducing the dietary acid load has a positive effect on maintenance of bone. In study 1, (n = 11, 60-90 d bed rest), the renal acid load of the diet was estimated from its chemical composition, and was positively correlated with urinary markers of bone resorption (P less than 0.05); that is, the greater the acid load, the greater the excretion of bone resorption markers. In study 2, in males (n = 8, 30 d bed rest), an estimate of the ratio of nonvolatile acid precursors to base precursors in the diet was positively correlated (P less than 0.05) with markers of bone resorption. In study 3, for 28 d subjects received either a placebo (n = 6) or an essential amino acid supplement (n = 7) that included methionine, a known acid precursor. During bed rest (28 d), urinary calcium was greater than baseline levels in the supplemented group but not the control group (P less than 0.05), and in the supplemented group, urinary pH decreased (P less than 0.05). In study 4, less bone resorption occurred in space crew members who received potassium citrate (n = 6) during spaceflight of 4-6 months than in crew members who received placebo or were not in the study (n = 8) (P less than 0.05). Reducing acid load has the potential to mitigate increased bone resorption during spaceflight, and may serve as a bone loss countermeasure.

In Vitro and Ex Vivo Evaluation of Novel Curcumin-Loaded Excipient for Buccal Delivery.

PubMed

Laffleur, Flavia; Schmelzle, Franziska; Ganner, Ariane; Vanicek, Stefan

2017-08-01

This study aimed to develop a mucoadhesive polymeric excipient comprising curcumin for buccal delivery. Curcumin encompasses broad range of benefits such as antioxidant, anti-inflammatory, and chemotherapeutic activity. Hyaluronic acid (HA) as polymeric excipient was modified by immobilization of thiol bearing ligands. L-Cysteine (SH) ethyl ester was covalently attached via amide bond formation between cysteine and the carboxylic moiety of hyaluronic acid. Succeeded synthesis was proved by H-NMR and IR spectra. The obtained thiolated polymer hyaluronic acid ethyl ester (HA-SH) was evaluated in terms of stability, safety, mucoadhesiveness, drug release, and permeation-enhancing properties. HA-SH showed 2.75-fold higher swelling capacity over time in comparison to unmodified polymer. Furthermore, mucoadhesion increased 3.4-fold in case of HA-SH and drug release was increased 1.6-fold versus HA control, respectively. Curcumin-loaded HA-SH exhibits a 4.4-fold higher permeation compared with respective HA. Taking these outcomes in consideration, novel curcumin-loaded excipient, namely thiolated hyaluronic acid ethyl ester appears as promising tool for pharyngeal diseases.

Improved insulin loading in poly(lactic-co-glycolic) acid (PLGA) nanoparticles upon self-assembly with lipids.

PubMed

García-Díaz, María; Foged, Camilla; Nielsen, Hanne Mørck

2015-03-30

Polymeric nanoparticles are widely investigated as drug delivery systems for oral administration. However, the hydrophobic nature of many polymers hampers effective loading of the particles with hydrophilic macromolecules such as insulin. Thus, the aim of this work was to improve the loading of insulin into poly(lactic-co-glycolic) acid (PLGA) nanoparticles by pre-assembly with amphiphilic lipids. Insulin was complexed with soybean phosphatidylcholine or sodium caprate by self-assembly and subsequently loaded into PLGA nanoparticles by using the double emulsion-solvent evaporation technique. The nanoparticles were characterized in terms of size, zeta potential, insulin encapsulation efficiency and loading capacity. Upon pre-assembly with lipids, there was an increased distribution of insulin into the organic phase of the emulsion, eventually resulting in significantly enhanced encapsulation efficiencies (90% as compared to 24% in the absence of lipids). Importantly, the insulin loading capacity was increased up to 20% by using the lipid-insulin complexes. The results further showed that a main fraction of the lipid was incorporated into the nanoparticles and remained associated to the polymer during release studies in buffers, whereas insulin was released in a non-complexed form as a burst of approximately 80% of the loaded insulin. In conclusion, the protein load in PLGA nanoparticles can be significantly increased by employing self-assembled protein-lipid complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of aeration rate and waste load on evolution of volatile fatty acids and waste stabilization during thermophilic aerobic digestion of a model high strength agricultural waste.

PubMed

Ugwuanyi, J Obeta; Harvey, L M; McNeil, B

2005-04-01

Thermophilic aerobic digestion (TAD) is a relatively new, dynamic and versatile low technology for the economic processing of high strength waste slurries. Waste so treated may be safely disposed of or reused. In this work a model high strength agricultural waste, potato peel, was subjected to TAD to study the effects of oxygen supply at 0.1, 0.25, 0.5 and 1.0 vvm (volume air per volume slurry per minute) under batch conditions at 55 degrees C for 156 h on the process. Process pH was controlled at 7.0 or left unregulated. Effects of waste load, as soluble chemical oxygen demand (COD), on TAD were studied at 4.0, 8.0, 12.0 and 16.0 gl(-1) (soluble COD) at pH 7.0, 0.5 vvm and 55 degrees C. Efficiency of treatment, as degradation of total solids, total suspended solids and soluble solid, as well as soluble COD significantly increased with aeration rate, while acetate production increased as the aeration rate decreased or waste load increased, signifying deterioration in treatment. Negligible acetate, and no other acids were produced at 1.0 vvm. Production of propionate and other acids increased after acetate concentration had started to decrease and, during unregulated reactions coincided with the drop in the pH of the slurry. Acetate production was more closely associated with periods of oxygen limitation than were other acids. Reduction in oxygen availability led to deterioration in treatment efficiency as did increase in waste load. These variables may be manipulated to control treated waste quality.

Effects of oleic acid surface coating on the properties of nickel ferrite nanoparticles/PLA composites.

PubMed

Yin, Hong; Chow, Gan-Moog

2009-11-01

Nickel ferrite nanoparticles with or without oleic acid surface coating were mixed with poly(D,L-lactide) (PLA) by double emulsion method. If the nanoparticles were prepared without oleic acid coating, they adsorbed on the PLA surface. If the nanoparticles were coated with oleic acid, they could be readily encapsulated within the PLA microspheres. A slight depression in glass transition temperature was found in all composites and it could be related to the interfacial energies between nanoparticles and PLA. Optimum mixed composite was achieved by reducing interfacial energy. However, loading capacity was limited in this composite. Increasing the amount of nickel ferrite nanoparticles was not useful to increase loading capacity. Cytotoxicity of the composite decreased significantly when nickel ferrite nanoparticles were effectively encapsulated in PLA microspheres. (c) 2008 Wiley Periodicals, Inc.

Micro-emulsification/encapsulation of krill oil by complex coacervation with krill protein isolated using isoelectric solubilization/precipitation.

PubMed

Shi, Liu; Beamer, Sarah K; Yang, Hong; Jaczynski, Jacek

2018-04-01

This study determined feasibility of krill protein isolated with isoelectric solubilization/precipitation (ISP) as wall material to microencapsulate krill oil by freeze-drying. Effects of krill oil/krill protein ratio on properties of microcapsules were investigated. With increased ratio, crude protein of microcapsules decreased, while total lipid increased. Although microcapsule oil loading capacity increased, loading and encapsulation efficiencies decreased. Thin layer chromatography (TLC) confirmed abundance of phospholipids, which are amphiphilic; and thus, resulted in stable emulsion (emulsion stability index). Microcapsules contained ω-3 polyunsaturated fatty acids (PUFAs) at 43-60, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at 28-41 and 9-11 g/100g of total FAs, respectively. SDS-PAGE electrophoresis revealed proteolysis of ISP krill protein, probably causing reduced loading and encapsulation efficiencies. SEM showed that krill oil/krill protein ratio affected surface microstructure. ISP krill protein showed potential as a wall material to microencapsulate krill oil; and thus, expand application of krill oil/protein for human consumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extremely fast increase in the organic loading rate during the co-digestion of rapeseed oil and sewage sludge in a CSTR--characterization of granules formed due to CaO addition to maintain process stability.

PubMed

Kasina, M; Kleyböcker, A; Michalik, M; Würdemann, H

2015-01-01

In a co-digestion system running with rapeseed oil and sewage sludge, an extremely fast increase in the organic loading rate was studied to develop a procedure to allow for flexible and demand-driven energy production. The over-acidification of the digestate was successfully prevented by calcium oxide dosage, which resulted in granule formation. Mineralogical analyses revealed that the granules were composed of insoluble salts of long chain fatty acids and calcium and had a porous structure. Long chain fatty acids and calcium formed the outer cover of granules and offered interfaces on the inside thereby enhancing the growth of biofilms. With granule size and age, the pore size increased and indicated degradation of granular interfaces. A stable biogas production up to the organic loading rate of 10.4 kg volatile solids m(-3) d(-1) was achieved although the hydrogen concentration was not favorable for propionic acid degradation. However, at higher organic loading rates, unbalanced granule formation and degradation were observed. Obviously, the adaption time for biofilm growth was too short to maintain the balance, thereby resulting in a low methane yield.

Metal loading levels influence on REE distribution on humic acid: Experimental and Modelling approach

NASA Astrophysics Data System (ADS)

Marsac, R.; Davranche, M.; Gruau, G.; Dia, A.

2009-04-01

In natural organic-rich waters, rare earth elements (REE) speciation is mainly controlled by organic colloids such as humic acid (HA). Different series of REE-HA complexation experiments performed at several metal loading (REE/C) displayed two pattern shapes (i) at high metal loading, a middle-REE (MREE) downward concavity, and (ii) at low metal loading, a regular increase from La to Lu (e.g. Sonke and Salters, 2006; Pourret et al., 2007). Both REE patterns might be related to REE binding with different surface sites on HA. To understand REE-HA binding, REE-HA complexation experiments at various metals loading were carried out using ultrafiltration combined with ICP-MS measurements, for the 14 REE simultaneously. The patterns of the apparent coefficients of REE partition between HA and the inorganic solution (log Kd) evolved regularly according to the metal loading. The REE patterns presented a MREE downward concavity at low loading and a regular increase from La to Lu at high loading. The dataset was modelled with Model VI by adjusting two specific parameters, log KMA, the apparent complexation constant of HA low affinity sites and DLK2, the parameter increasing high affinity sites binding strength. Experiments and modelling provided evidence that HA high affinity sites controlled the REE binding with HA at low metal loading. The REE-HA complex could be as multidentate complexes with carboxylic or phenolic sites or potentially with sites constituted of N, P or S as donor atoms. Moreover, these high affinity sites could be different for light and heavy REE, because heavy REE have higher affinity for these sites, in low density, and could saturate them. These new Model VI parameter sets allowed the prediction of the REE-HA pattern shape evolution on a large range of pH and metal loading. According to the metal loading, the evolution of the calculated REE patterns was similar to the various REE pattern observed in natural acidic organic-rich waters (pH<7 and DOC>10 mg L-1). As a consequence, the metal loading could be the key parameter controlling the REE pattern in organic-rich waters.

The rate of synthesis and decomposition of tissue proteins in hypokinesia and increased muscular activity

NASA Technical Reports Server (NTRS)

Fedorov, I. V.; Chernyy, A. V.; Fedorov, A. I.

1978-01-01

During hypokinesia and physical loading (swimming) of rats, the radioactivity of skeletal muscle, liver, kidney, heart, and blood proteins was determined after administration of radioactive amino acids. Tissue protein synthesis decreased during hypokinesia, and decomposition increased. Both synthesis and decomposition increased during physical loading, but anabolic processes predominated in the total tissue balance. The weights of the animals decreased in hypokinesia and increased during increased muscle activity.

The role of non-covalent interactions in anticancer drug loading and kinetic stability of polymeric micelles.

PubMed

Yang, Chuan; Attia, Amalina B Ebrahim; Tan, Jeremy P K; Ke, Xiyu; Gao, Shujun; Hedrick, James L; Yang, Yi-Yan

2012-04-01

A new series of acid- and urea-functionalized polycarbonate block copolymers were synthesized via organocatalytic living ring-opening polymerization using methoxy poly(ethylene glycol) (PEG) as a macroinitiator to form micelles as drug delivery carriers. The micelles were characterized for critical micelle concentration, particle size and size distribution, kinetic stability and loading capacity for a model anticancer drug, doxorubicin (DOX) having an amine group. The acid/urea groups were placed in block forms (i.e. acid as the middle block or the end block) or randomly distributed in the polycarbonate block to investigate molecular structure effect. The micelles formed from the polymers in both random and block forms provided high drug loading capacity due to strong ionic interaction between the acid in the polymer and the amine in DOX. However, the polymers with acid and urea groups placed in the block forms formed micelles with wider size distribution (two size populations), and their DOX-loaded micelles were less stable. The number of acid/urea groups in the random form was further varied from 5 to 8, 13 and 19 to study its effects on self-assembly behaviors and DOX loading. An increased number of acid/urea groups yielded DOX-loaded micelles with smaller size and enhanced kinetic stability because of improved inter-molecular polycarbonate-polycarbonate (urea-urea and urea-acid) hydrogen-bonding and polycarbonate-DOX (acid-amine) ionic interactions. However, when the number of acid/urea groups was 13 or higher, micelles aggregated in a serum-containing medium, and freeze-dried DOX-loaded micelles were unable to re-disperse in an aqueous solution. Among all the polymers synthesized in this study, 1b with 8 acid/urea groups in the random form had the optimum properties. In vitro release studies showed that DOX release from 1b micelles was sustained over 7 h without significant initial burst release. MTT assays demonstrated that the polymer was not toxic towards HepG2 and HEK293 cells. Importantly, DOX-loaded micelles were potent against HepG2 cells with IC(50) of 0.26 mg/L, comparable to that of free DOX (IC(50): 0.20 mg/L). In addition, DOX-loaded 1b micelles yielded lower DOX content in the heart tissue of the tested mice as compared to free DOX formulation after i.v. injection. These findings signify that 1b micelles may be a promising carrier for delivery of anticancer drugs that contain amine groups. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of environmental factors on pesticide adsorption by black carbon: pH and model dissolved organic matter.

PubMed

Qiu, Yuping; Xiao, Xiaoyu; Cheng, Haiyan; Zhou, Zunlong; Sheng, G Daniel

2009-07-01

Loading two organic acids of known molecular structures onto a black carbon was conducted to study the influence of pH and dissolved organic matter on the adsorption of pesticides. Tannic acid at the loading rates of 100 and 300 micromol/g reduced the surface area of black carbon by 18 and 63%, respectively. This was due principally to the blockage of micropores, as verified by measured pore volumes and pore-size distributions. With a comparatively much smaller molecular structure, gallic acid did not apparently influence these properties. The intrinsic acidities of the two acids increased the surface acidity from 1.88 mmol/g of black carbon to 1.93-2.02 mmol/g after DOM loading, resulting in a reduction in isoelectric point pH from 1.93 to 1.66-1.82. The adsorption of propanil, 2,4-D and prometon by black carbon free and loaded of DOM was dependent on pH because major adsorptive forces were the interactions between neutral pesticide molecules and uncharged carbon surfaces. The adsorption was diminished considerably by the deprotonation of 2,4-D and protonation of prometon, as well as the surface charge change of black carbon. Tannic acid of 100 and 300 micromol/g on black carbon reduced the pesticide adsorption at the equilibrium concentration of 10 mg/L by an average of 46 and 81%, respectively, consistent with the reductions of 42 and 81% in micropore volume. At the equilibrium concentration of 30 mg/L, the mesopore surface became the additional adsorptive domain for propanil. Loading tannic acid made the mesopore surface less accessible, due presumably to the enhanced obstruction by tannic acid.

Effects of nitrogen fertilization on the acidity and salinity of greenhouse soils.

PubMed

Han, Jiangpei; Shi, Jiachun; Zeng, Lingzao; Xu, Jianming; Wu, Laosheng

2015-02-01

A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity. Three N rates (urea; N0, 0 kg N ha(-1); N1, 600 kg N ha(-1); and N2, 1,200 kg N ha(-1)) were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production. Both soil acidity and salinity increased significantly as N input increased after one season, with pH decrease ranging from 0.45 to 1.06 units and electrolytic conductivity increase from 0.24 to 0.68 mS cm(-1). An estimated 0.92 mol H(+) was produced for 1 mol (NO2 (-) + NO3 (-))-N accumulation in soil. The proton loading from nitrification was 14.3-27.3 and 12.1-58.2 kmol H(+) ha(-1) in the center of Shandong Province under N1 and N2 rate, respectively. However, the proton loading from the uptake of excess bases by lettuces was only 0.3-4.5 % of that from nitrification. Moreover, the release of protons induced the direct release of base cations and accelerated soil salinization. The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer. Compared to the proton loading by lettuce, nitrification contributed more to soil acidification in greenhouse soils.

Preparation, characterization and pharmacokinetics of enrofloxacin-loaded solid lipid nanoparticles: influences of fatty acids.

PubMed

Xie, Shuyu; Zhu, Luyan; Dong, Zhao; Wang, Xiaofang; Wang, Yan; Li, Xihe; Zhou, WenZhong

2011-04-01

Enrofloxacin-loaded solid lipid nanoparticles (SLN) were prepared using fatty acids (tetradecanoic acid, palmitic acid, stearic acid) as lipid matrix by hot homogenization and ultrasonication method. The effect of fatty acids on the characteristics and pharmacokinetics of the SLN were investigated. The results showed that the encapsulation efficiency and loading capacity of nanoparticles varied with fatty acids in the order of stearic acid>palmitic acid>tetradecanoic acid. Furthermore, stearic acid-SLN had larger particle size, bigger polydispersity index (PDI) and higher zeta potential compared with the other two fatty acid formulated SLN. The SLN showed sustained releases in vitro and the released enrofloxacin had the same antibacterial activity as that of the native enrofloxacin. Although in vitro release exhibited similar patterns, within 24 h the releasing rates of the three formulations were significantly different (tetradecanoic acid-SLN>palmitic acid-SLN>stearic acid-SLN). Pharmacokinetic study after a single dose of intramuscular administration to mice demonstrated that tetradecanoic acid-SLN, palmitic acid-SLN, and stearic acid-SLN increased the bioavailability by 6.79, 3.56 and 2.39 folds, and extended the mean residence time (MRT) of the drug from 10.60 h to 180.36, 46.26 and 19.09 h, respectively. These results suggest that the enrofloxacin-fatty acid SLN are promising formulations for sustained release while fatty acids had significant influences on the characteristics and performances of the SLN. Copyright © 2010 Elsevier B.V. All rights reserved.

Farnesylthiosalicylic acid-loaded lipid-polyethylene glycol-polymer hybrid nanoparticles for treatment of glioblastoma.

PubMed

Kaffashi, Abbas; Lüle, Sevda; Bozdağ Pehlivan, Sibel; Sarısözen, Can; Vural, İmran; Koşucu, Hüsnü; Demir, Taner; Buğdaycı, Kadir Emre; Söylemezoğlu, Figen; Karlı Oğuz, Kader; Mut, Melike

2017-08-01

We aimed to develop lipid-polyethylene glycol (PEG)-polymer hybrid nanoparticles, which have high affinity to tumour tissue with active ingredient, a new generation antineoplastic drug, farnesylthiosalicylic acid (FTA) for treatment of glioblastoma. Farnesylthiosalicylic acid-loaded poly(lactic-co-glycolic acid)-1,2 distearoyl-glycerol-3-phospho-ethanolamine-N [methoxy (PEG)-2000] ammonium salt (PLGA-DSPE-PEG) with or without 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) hybrid nanoparticles has been prepared and evaluated for in-vitro characterization. Cytotoxicity of FTA-loaded nanoparticles along with its efficacy on rat glioma-2 (RG2) cells was also evaluated both in vitro (in comparison with non-malignant cell line, L929) and in vivo. Scanning electron microscopy studies showed that all formulations prepared had smooth surface and spherical in shape. FTA and FTA-loaded nanoparticles have cytotoxic activity against RG2 glioma cell lines in cell culture studies, which further increases with addition of DOTAP. Magnetic resonance imaging and histopathologic evaluation on RG2 tumour cells in rat glioma model (49 female Wistar rats, 250-300 g) comparing intravenous and intratumoral injections of the drug have been performed and FTA-loaded nanoparticles reduced tumour size significantly in in-vivo studies, with higher efficiency of intratumoral administration than intravenous route. Farnesylthiosalicylic acid-loaded PLGA-DSPE-PEG-DOTAP hybrid nanoparticles are proven to be effective against glioblastoma in both in-vitro and in-vivo experiments. © 2017 Royal Pharmaceutical Society.

A review of the calculation procedure for critical acid loads for terrestrial ecosystems.

PubMed

van der Salm, C; de Vries, W

2001-04-23

Target loads for acid deposition in the Netherlands, as formulated in the Dutch environmental policy plan, are based on critical load calculations at the end of the 1980s. Since then knowledge on the effect of acid deposition on terrestrial ecosystems has substantially increased. In the early 1990s a simple mass balance model was developed to calculate critical loads. This model was evaluated and the methods were adapted to represent the current knowledge. The main changes in the model are the use of actual empirical relationships between Al and H concentrations in the soil solution, the addition of a constant base saturation as a second criterion for soil quality and the use of tree species-dependant critical Al/base cation (BC) ratios for Dutch circumstances. The changes in the model parameterisation and in the Al/BC criteria led to considerably (50%) higher critical loads for root damage. The addition of a second criterion in the critical load calculations for soil quality caused a decrease in the critical loads for soils with a median to high base saturation such as loess and clay soils. The adaptation hardly effected the median critical load for soil quality in the Netherlands, since only 15% of the Dutch forests occur on these soils. On a regional scale, however, critical loads were (much) lower in areas where those soils are located.

Optimization of the Synthesis of Structured Phosphatidylcholine with Medium Chain Fatty Acid.

PubMed

Ochoa-Flores, Angélica A; Hernández-Becerra, Josafat A; Cavazos-Garduño, Adriana; Vernon-Carter, Eduardo J; García, Hugo S

2017-11-01

Structured phosphatidylcholine was successfully produced by acidolysis between phosphatidylcholine and free medium chain fatty acid, using phospholipase A 1 immobilized on Duolite A568. Response surface methodology was applied to optimize the reaction system using three process parameters: molar ratio of substrates (phosphatidylcholine to free medium chain fatty acid), enzyme loading, and reaction temperature. All parameters evaluated showed linear and quadratic significant effects on the production of modified phosphatidylcholine; molar ratio of substrates contributed positively, but temperature influenced negatively. Increased enzyme loading also led to increased production of modified phosphatidylcholine but only during the first 9 hours of the acidolysis reaction. Optimal conditions obtained from the model were a ratio of phosphatidylcholine to free medium chain fatty acid of 1:15, an enzyme loading of 12%, and a temperature of 45°C. Under these conditions a production of modified phosphatidylcholine of 52.98 % were obtained after 24 h of reaction. The prediction was confirmed from the verification experiments; the production of modified phosphatidylcholine was 53.02%, the total yield of phosphatidylcholine 64.28% and the molar incorporation of medium chain fatty acid was 42.31%. The acidolysis reaction was scaled-up in a batch reactor with a similar production of modified phosphatidylcholine, total yield of phosphatidylcholine and molar incorporation of medium chain fatty acid. Purification by column chromatography of the structured phosphatidylcholine yielded 62.53% of phosphatidylcholine enriched with 42.52% of medium chain fatty acid.

Thermo- and pH-Responsive Copolymers Bearing Cholic Acid and Oligo(ethylene glycol) Pendants: Self-Assembly and pH-Controlled Release.

PubMed

Jia, Yong-Guang; Zhu, X X

2015-11-11

A family of block and random copolymers of norbornene derivatives bearing cholic acid and oligo(ethylene glycol) pendants were prepared in the presence of Grubbs' catalyst. The phase transition temperature of the copolymers in aqueous solutions may be tuned by the variation of comonomer ratios and pH values. Both types of copolymers formed micellar nanostructures with a hydrophilic poly(ethylene glycol) shell and a hydrophobic core containing cholic acid residues. The micellar size increased gradually with increasing pH due to the deprotonation of the carboxylic acid groups. These micelles were capable of encapsulating hydrophobic compounds such as Nile Red (NR). A higher hydrophobicity/hydrophilicity ratio in both copolymers resulted in a higher loading capacity for NR. With similar molecular weights and monomer compositions, the block copolymers showed a higher loading capacity for NR than the random copolymers. The NR-loaded micelles exhibited a pH-triggered release behavior. At pH 7.4 within 96 h, the micelles formed by the block and random of copolymers released 56 and 97% NR, respectively. Therefore, these micelles may have promise for use as therapeutic nanocarriers in drug delivery systems.

Long-term performance of high-rate anaerobic reactors for the treatment of oily wastewater.

PubMed

Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2006-10-15

Complex oily wastewater from a food industry was treated in three different UASB reactors at different operating conditions. Although all three systems achieved fat, oil, and grease (FOG) and COD removal efficiencies above 80% at an organic loading of 3 kg COD/m3 x d, system performance deteriorated sharply at higher loading rates, and the presence of high FOG caused a severe sludge flotation resulting in failure. Initially, FOG accumulated onto the biomass which led to sludge flotation and washout of biomass. The loss of sludge in the bed increased the FOG loading to the biomass and failure ensued. Contrary to previous findings, accumulation of FOG rather than influent FOG concentrations or volumetric FOG loading rate was the most importantfactor governing the high-rate anaerobic reactor performance. The critical accumulated FOG loading was identified as 1.04 +/- 0.13 g FOG/g VSS for all three reactors. Furthermore, FOG accumulation onto the biomass was identified mainly as palmitic acid (>60%) whereas the feed LCFA contained only 30% of palmitic acid and 50% of oleic acid.

Effects of poly (lactic-co-glycolic acid) as a co-emulsifier on the preparation and hypoglycaemic activity of insulin-loaded solid lipid nanoparticles.

PubMed

Wang, S L; Xie, S Y; Zhu, L Y; Wang, F H; Zhou, W Z

2009-12-01

Poly (lactic-co-glycolic acid) (PLGA) was used as a co-emulsifier in the preparation of insulin-loaded solid lipid nanoparticles (SLN) with hydrogenated castor oil as lipid matrix and lecithin as surfactant by double-emulsion technique. The effects of PLGA on the preparation and hypoglycaemic activity of insulin-loaded SLN were studied. The results showed that with the supplement of PLGA, the encapsulation efficiency and loading capacity were increased significantly from 79.08 +/- 1.62 to 85.57 +/- 3.21% and 1.58 +/- 0.03 to 1.71 +/- 0.06%, whereas the surface charge and particle size were changed insignificantly from -25.87 +/- 2.65 to -22.67 +/- 1.19 mv and 431.0 +/- 16.1 to 397.0 +/- 68.0 nm, respectively. In vivo studies demonstrated that PLGA increased the sustained hypoglycaemic activity from 12 to 36 h and 24 to 120 h in normal and steptozotocin-induced diabetic mice after a single intramuscular injection of the insulin-loaded SLN. These results demonstrated that PLGA could enhance the entrapment of insulin in the nanoparticles, and more importantly, prolong the time of hypoglycaemic activity of the insulin-loaded SLN.

Increased cellular uptake of lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles due to surface modification with folic acid.

PubMed

Feuser, Paulo Emilio; Arévalo, Juan Marcelo Carpio; Junior, Enio Lima; Rossi, Gustavo Rodrigues; da Silva Trindade, Edvaldo; Rocha, Maria Eliane Merlin; Jacques, Amanda Virtuoso; Ricci-Júnior, Eduardo; Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H Hermes

2016-12-01

Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid were synthesized by miniemulsion polymerization in just one step. In vitro biocompatibility and cytotoxicity assays on L929 (murine fibroblast), human red blood, and HeLa (uterine colon cancer) cells were performed. The effect of folic acid at the nanoparticles surface was evaluated through cellular uptake assays in HeLa cells. Results showed that the presence of folic acid did not affect substantially the polymer particle size (~120 nm), the superparamagnetic behavior, the encapsulation efficiency of lauryl gallate (~87 %), the Zeta potential (~38 mV) of the polymeric nanoparticles or the release profile of lauryl gallate. The release profile of lauryl gallate from superparamagnetic poly(methyl methacrylate) nanoparticles presented an initial burst effect (0-1 h) followed by a slow and sustained release, indicating a biphasic release system. Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles with folic acid did not present cytotoxicity effects on L929 and human red blood cells. However, free lauryl gallate presented significant cytotoxic effects on L929 and human red blood cells at all tested concentrations. The presence of folic acid increased the cytotoxicity of lauryl gallate loaded in nanoparticles on HeLa cells due to a higher cellular uptake when HeLa cells were incubated at 37 °C. On the other hand, when the nanoparticles were incubated at low temperature (4 °C) cellular uptake was not observed, suggesting that the uptake occurred by folate receptor mediated energy-dependent endocytosis. Based on presented results our work suggests that this carrier system can be an excellent alternative in targeted drug delivery by folate receptor.

Kinetic Study on the Removal of Iron from Gold Mine Tailings by Citric Acid

NASA Astrophysics Data System (ADS)

Mashifana, T.; Mavimbela, N.; Sithole, N.

2018-03-01

The Gold mining generates large volumes of tailings, with consequent disposal and environmental problems. Iron tends to react with sulphur to form pyrite and pyrrhotite which then react with rain water forming acid rain. The study focuses on the removal of iron (Fe) from Gold Mine tailings; Fe was leached using citric acid as a leaching reagent. Three parameters which have an effect on the removal of Fe from the gold mine tailings, namely; temperature (25 °C and 50 °C), reagent concentration (0.25 M, 0.5 M, 0.75 M and 1 M) and solid loading ratio (20 %, 30 % and 40 %) were investigated. It was found that the recovery of Fe from gold mine tailings increased with increasing temperature and reagent concentration, but decreased with increasing solid loading ratio. The optimum conditions for the recovery of Fe from gold mine tailings was found to be at a temperature of 50 ºC, reagent concentration of 1 M and solid loading of 20 %. Three linear kinetic models were investigated and Prout-Tompkins kinetic model was the best fit yielding linear graphs with the highest R2 values.

Erosion and attrition of human enamel in vitro part II: influence of time and loading.

PubMed

Eisenburger, M; Addy, M

2002-01-01

To determine the influence of load and time on enamel wear by attrition under neutral and acid environments in vitro. Groups of 10 enamel cusp and smooth surface specimens obtained from unerupted third molars were opposed in a wear machine under loads of 200, 400 and 600 g in citric acid at pH 3.2 and in physiological saline at 35 degrees C for 30 min (2280 wear cycles). The experiment was repeated with a load of 600 g for 10 and 20 min accompanied by 10 taped specimens to measure erosion only. Erosion and attrition of smooth surface specimens was determined by profilometry. At a load of 600 g attrition in saline increased with time from 7.9 microm (SD 3.7 microm) at 10 min, 10.2 microm (SD 4.8 microm) at 20-25.5 microm (SD 9.1 microm) after 30 min and combined attrition/erosion in citric acid from 1.5 microm (SD 0.4 microm) to 2.5 microm (SD 0.9 microm) to 6.0 microm (SD 3.7 microm). At a fixed time of 30 min, attrition in saline was 5.2 microm (SD 3.6 microm) at 200 g and 8.1 microm (SD 1.5 microm) at 400 g and combined attrition/erosion in citric acid 2.8 microm (SD 1.2 microm) and 3.6 microm (SD 0.7 microm). Comparison between both environments revealed significant differences at fixed load at all time points (p < 0.01) and at fixed time between 400 and 600 g (p < 0.01). Load and time significantly influence enamel wear both in acid and neutral conditions but the effects were not linear. Copyright 2002 Elsevier Science Ltd.

Pretreatment of corn stover for sugar production using dilute hydrochloric acid followed by lime.

PubMed

Zu, Shuai; Li, Wen-zhi; Zhang, Mingjian; Li, Zihong; Wang, Ziyu; Jameel, Hasan; Chang, Hou-min

2014-01-01

In this study, a two stage process was evaluated to increase the sugar recovery. Firstly, corn stover was treated with diluted hydrochloric acid to maximize the xylose yield, and then the residue was treated with lime to alter the lignin structure and swell the cellulose surface. The optimal condition was 120 °C and 40 min for diluted hydrochloric acid pretreatment followed by lime pretreatment at 60 °C for 12h with lime loading at 0.1 g/g of substrate. The glucose and xylose yield was 78.0% and 97.0%, respectively, with cellulase dosage at 5 FPU/g of substrate. The total glucose yield increased to 85.9% when the cellulase loading was increased to 10 FPU/g of substrate. This two stage process was effective due to the swelling of the internal surface, an increase in the porosity and a decrease in the degree of polymerization. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Comparison of the effect of continuous and intermittent physical loading in type I diabetics].

PubMed

Rusavý, Z; Lacigová, S; Holecek, T; Srámek, V; Novák, I; Tĕsínský, P

1994-07-01

In order to evaluate the optimal mode of physical loads the authors examined 19 diabetics type I without secondary complications. On the second day of an educational-rehabilitation camp the authors subjected the patients to a continuous load-a 40-minute endurance run at a heart rate equal to 60% of the maximal oxygen requirement. On the fifth day an intermittent load with a maximal intensity--training of 4 x 10 minutes with 5-minute intervals was administered. At the onset, during the 20th and 40th minute of the load the titrable acidity, lactate and blood sugar level were assessed. The intermittent load led already after 20 minutes to marked acidosis (titrable acidity = 12) which did not increase after 40 minutes of the load. The authors recorded a statistically significant rise of the lactate level (4.57 mmol/l) which after 40 minutes of the load rose further to 12.3 mmol/l, as compared with values of titrable acidity during the 20th and 40th minute (0.44 and 1.14) and lactate during the 20th and 40th minute (4.57 and 3.86 mmol/l) during a continuous load. After evaluation by the test of linear correlation it appears with regard to the stability of the blood sugar level during a load that an intermittent load is more favourable. The drop of the blood sugar level in time during a continuous load was at the 1 level of significance, in intermittent loads at the 5% of significance. Both types of loads did not lead to hypoglycaemia or other complications and thus both can be used in diabetics type I.

α-Ketoglutarate regulates acid-base balance through an intrarenal paracrine mechanism

PubMed Central

Tokonami, Natsuko; Morla, Luciana; Centeno, Gabriel; Mordasini, David; Ramakrishnan, Suresh Krishna; Nikolaeva, Svetlana; Wagner, Carsten A.; Bonny, Olivier; Houillier, Pascal; Doucet, Alain; Firsov, Dmitri

2013-01-01

Paracrine communication between different parts of the renal tubule is increasingly recognized as an important determinant of renal function. Previous studies have shown that changes in dietary acid-base load can reverse the direction of apical α-ketoglutarate (αKG) transport in the proximal tubule and Henle’s loop from reabsorption (acid load) to secretion (base load). Here we show that the resulting changes in the luminal concentrations of αKG are sensed by the αKG receptor OXGR1 expressed in the type B and non-A–non-B intercalated cells of the connecting tubule (CNT) and the cortical collecting duct (CCD). The addition of 1 mM αKG to the tubular lumen strongly stimulated Cl–-dependent HCO3– secretion and electroneutral transepithelial NaCl reabsorption in microperfused CCDs of wild-type mice but not Oxgr1–/– mice. Analysis of alkali-loaded mice revealed a significantly reduced ability of Oxgr1–/– mice to maintain acid-base balance. Collectively, these results demonstrate that OXGR1 is involved in the adaptive regulation of HCO3– secretion and NaCl reabsorption in the CNT/CCD under acid-base stress and establish αKG as a paracrine mediator involved in the functional coordination of the proximal and the distal parts of the renal tubule. PMID:23934124

Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer.

PubMed

Zeisser-Labouèbe, Magali; Lange, Norbert; Gurny, Robert; Delie, Florence

2006-12-01

A photodynamic approach has been suggested to improve diagnosis and therapy of ovarian cancer. As Hypericin (Hy), a natural photosensitizer (PS) extracted from Hypericum perforatum, has been shown to be efficient in vitro and in vivo for the detection or treatment of other cancers, Hy could also be a potent tool for the treatment and detection of ovarian cancer. Due to its hydrophobicity, systemic administration of Hy is problematic. Thus, polymeric nanoparticles (NPs) of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA) were used as a drug delivery system. Hy-loaded NPs were produced with the following characteristics: (i) size in the 200-300 nm range, (ii) negative zeta potential, (iii) low residual PVAL and (iv) drug loading from 0.03 to 0.15% (w/w). Their in vitro photoactivity was investigated on the NuTu-19 ovarian cancer cell model derived from Fischer 344 rats and compared to free drug. Hy-loaded PLA NPs exhibited a higher photoactivity than free drug. Increasing light dose or incubation time with cells induced an enhanced activity of Hy-loaded PLA NPs. Increased NP drug loading had a negative effect on their photoactivity on NuTu-19 cells: at the same Hy concentration, the higher was the drug loading, the lower was the phototoxic effect. The influence of NP drug loading on the Hy release from NPs was also investigated.

Dietary acid load and risk of type 2 diabetes: the E3N-EPIC cohort study.

PubMed

Fagherazzi, Guy; Vilier, Alice; Bonnet, Fabrice; Lajous, Martin; Balkau, Beverley; Boutron-Rualt, Marie-Christine; Clavel-Chapelon, Françoise

2014-02-01

The objective of this study was to evaluate the prospective relationship between dietary acid load, assessed with both the potential renal acid load (PRAL) and the net endogenous acid production (NEAP) scores, and type 2 diabetes risk. A total of 66,485 women from the E3N-EPIC cohort were followed for incident diabetes over 14 years. PRAL and NEAP scores were derived from nutrient intakes. HRs for type 2 diabetes risk across quartiles of the baseline PRAL and NEAP scores were estimated with multivariate Cox regression models. During follow-up, 1,372 cases of incident type 2 diabetes were validated. In the overall population, the highest PRAL quartile, reflecting a greater acid-forming potential, was associated with a significant increase in type 2 diabetes risk, compared with the first quartile (HR 1.56, 95% CI 1.29, 1.90). The association was stronger among women with BMI <25 kg/m2 (HR 1.96, 95% CI 1.43, 2.69) than in overweight women (HR 1.28, 95% CI 1.00, 1.64); statistically significant trends in risk across quartiles were observed in both groups (p trend < 0.0001 and p trend = 0.03, respectively). The NEAP score provided similar findings. We have demonstrated for the first time in a large prospective study that dietary acid load was positively associated with type 2 diabetes risk, independently of other known risk factors for diabetes. Our results need to be validated in other populations, and may lead to promotion of diets with a low acid load for the prevention of diabetes. Further research is required on the underlying mechanisms.

Idiopathic recurrent calcium urolithiasis (IRCU): an acid meal challenge uncovers inappropriate pH of postprandial, fasting and daily urine: a cross-sectional study of male patients providing insight into post- and pre-load urinary stone substances, crystallization risk, presence of stones, renal transport and systemic metabolic factors.

PubMed

Schwille, Paul O; Wipplinger, J

2008-07-28

In IRCU the possible role of urinary pH (U-pH) as risk factor of calcium (Ca) stones is poorly understood. To evaluate in IRCU the response to an oral acid load, focussing on post- and pre-load U-pH, other urinary, renal and extra-renal factors, and linkage with Ca stones. - 237 male patients, either Ca stone-free (SF) or -bearing (SB), but without overt signs of systemic metabolic acidosis underwent a standardized laboratory programme that included, besides collection of urine and blood, the intake of an oxalate-free acid test meal (proton content 120 mM). Established analytical methods were used. In 79 patients the post-meal load U-pH was < or = 5.30 (in healthy individuals accepted as the upper limit after the same proton load), but >5.30 in 158; in these two subsets the mean fasting pre-load U-pH was 5.84 and 6.37 (p <0.001), the mean U-pH in 24 h urine 5.70 and 6.03 (p <0.001), the mean score of stone formation activity 32 and 42 (p = 0.12), the SF/SB ratio 35/44 and 76/82 (not significant). However, when in pre-load urine undissociated uric acid concentration was low due to the high pH, the SF/SB ratio was 53/66 (p = 0.038), whereas isolated increase of U-pH with SF/SB ratio 54/65 (p = 0.059), urinary supersaturation with Ca phosphate (hydroxyapatite), Ca oxalate, uric acid, and isolated decrease of concentration of total protein, total uric acid and the crystallization inhibitors magnesium and citrate failed to affect significantly the frequency distribution of SF and SB patients. Pre-load U-pH was positively associated with urinary ratio sodium/proton excretion, renal reclaim of sodium and protein, negatively associated with body mass index, fasting insulinemia and uricemia, urinary protein concentration, renal reclaim of phosphate. In IRCU 1) inappropriately high U-pH combined with increase of proteinuria and alteration of renal-tubular transport are frequent; 2) disturbed interactions of renal proton generation with sodium handling, urinary physico-chemical and systemic metabolic factors may initiate the development of Ca-containing concretions, presumably Ca phosphate, at some yet unknown renal anatomic site.

Removal of oxytetracycline (OTC) in a synthetic pharmaceutical wastewater by a sequential anaerobic multichamber bed reactor (AMCBR)/completely stirred tank reactor (CSTR) system: biodegradation and inhibition kinetics.

PubMed

Sponza, Delia Teresa; Çelebi, Hakan

2012-01-01

An anaerobic multichamber bed reactor (AMCBR) was effective in removing both molasses-chemical oxygen demand (COD), and the antibiotic oxytetracycline (OTC). The maximum COD and OTC removals were 99% in sequential AMCBR/completely stirred tank reactor (CSTR) at an OTC concentration of 300 mg L(-1). 51%, 29% and 9% of the total volatile fatty acid (TVFA) was composed of acetic, propionic acid and butyric acids, respectively. The OTC loading rates at between 22.22 and 133.33 g OTC m(-3) d(-1) improved the hydrolysis of molasses-COD (k), the maximum specific utilization of molasses-COD (k(mh)) and the maximum specific utilization rate of TVFA (k(TVFA)). The direct effect of high OTC loadings (155.56 and -177.78 g OTC m(-3) d(-1)) on acidogens and methanogens were evaluated with Haldane inhibition kinetic. A significant decrease of the Haldane inhibition constant was indicative of increases in toxicity at increasing loading rates. Copyright © 2011 Elsevier Ltd. All rights reserved.

TiO2/SiO2 porous composite thin films: Role of TiO2 areal loading and modification with gold nanospheres on the photocatalytic activity

NASA Astrophysics Data System (ADS)

Levchuk, Irina; Sillanpää, Mika; Guillard, Chantal; Gregori, Damia; Chateau, Denis; Parola, Stephane

2016-10-01

The aim of the work was to study photocatalytic activity of composite TiO2/Au/SiO2 thin films. Coatings were prepared using sol-gel technique. Physicochemical parameters of coatings were characterized using UV-vis spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry, tactile measurements, goniometry and diffuse reflectance measurements. The photocatalytic activity of the films was tested in batch mode using aqueous solution of formic acid. Changes of formic acid concentration were determined by means of high pressure liquid chromatography (HPLC). Increase of initial degradation rate of formic acid was detected for TiO2/Au/SiO2 films with gold nanoparticle's load 0.5 wt.% and 1.25 wt.%. However, deeper insights using more detailed characterization of these coatings demonstrated that the improvement of the photocatalytic activity is more probably attributed to an increase in the areal loading of TiO2.

Climate change impacts on forest soil critical acid loads and exceedances at a national scale

Treesearch

Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers

2013-01-01

Federal agencies are currently developing guidelines for forest soil critical acid loads across the United States. A critical acid load is defined as the amount of acid deposition (usually expressed on an annual basis) that an ecosystem can absorb. Traditionally, an ecosystem is considered to be at risk for health impairment when the critical acid load exceeds a level...

Removal of free fatty acid in Palm Fatty Acid Distillate using sulfonated carbon catalyst derived from biomass wastefor biodiesel production

NASA Astrophysics Data System (ADS)

Hidayat, Arif; Rochmadi; Wijaya, Karna; Budiman, Arief

2016-01-01

In this research, the esterification of PFAD using the sulfonatedcoconut shell biochar catalyst was studied. Carbon solid catalysts were prepared by a sulfonation of carbonized coconut shells. The performances of the catalysts were evaluated in terms of the reaction temperatures, the molar ratios of methanol to PFAD, the catalyst loading and the reaction times. The reusability of the solid acid carbon catalysts was also studied in this work. The results indicated that the FFA conversion was significantly increased with increasing catalyst loading and reaction times. It can be concluded that the optimal conditions were an PFAD to methanol molar ratio of 1:12, the amount of catalyst of 10%w, and reaction temperature of 60oC.At this optimum condition, the conversion to biodieselreached 88%.

Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

PubMed Central

2011-01-01

Background Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Methods Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Results Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis. Conclusions A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health. PMID:21529374

Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality.

PubMed

Fenton, Tanis R; Tough, Suzanne C; Lyon, Andrew W; Eliasziw, Misha; Hanley, David A

2011-04-30

Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis. A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.

Encapsulation of micronutrients resveratrol, genistein, and curcumin by folic acid-PAMAM nanoparticles.

PubMed

Chanphai, P; Tajmir-Riahi, H A

2018-05-21

It has been shown that encapsulation of dietary polyphenols leads to increased solubility and bioavailability of these micronutrients. The encapsulation of dietary polyphenols resveratrol, genistein, and curcumin by folic acid-PAMAM-G3 and folic acid-PAMAM-G4 nanoparticles was studied in aqueous solution at physiological conditions, using multiple spectroscopic methods, TEM images, and docking studies. The polyphenol bindings are via hydrophilic, hydrophobic, and H-bonding contacts with resveratrol forming more stable conjugates. As folic acid-PAMAM nanoparticle size increased, the loading efficacy and the stability of polyphenol-polymer conjugates were increased. Polyphenol encapsulation induced major alterations of dendrimer morphology. Folic acid-PAMAM nanoconjugates are capable of delivery of polyphenols in vitro.

Performance assessment of dilute-acid leaching to improve corn stover quality for thermochemical conversion

DOE PAGES

Aston, John E.; Thompson, David N.; Westover, Tyler L.

2016-08-30

Lignocellulosic biomass is a sustainable energy source that can help meet the increasing demand for biofuels in the United States. However, the quality and availability of such feedstocks greatly affects their suitability for downstream conversion. This work reports the effects of dilute-acid leaching at various solid loadings, temperatures and acid loadings on the quality of a traditional biochemical feedstock, corn stover, as a potential feedstock for thermochemical conversions. At 5 wt% solids, dilute-acid leaching was observed to effectively remove 97.3% of the alkali metals and alkaline earth metals that can negatively affect degradation pathways during pyrolysis and result in greatermore » yield of non-condensable gases. In addition, up to 98.4% of the chlorine and 88.8% of the phosphorus, which can cause equipment corrosion and foul upgrading catalysts, respectively, were removed. At 25°C in the absence of acid, only 6.8% of the alkali metals and alkaline earth metals were removed; however 88.0% of chloride was still removed. The ratio of alkaline/acidic ash species has been suggested to proportionately relate to slagging in biopower applications. The initial alkali/acid ratio of the ash species present in the untreated corn stover was 0.38 (significant slagging risk). At 5 wt% solids, this ratio was decreased to 0.18 (moderate slagging risk) at 0 wt% acid and 90°C, and was decreased to 0.07, 0.08 and 0.06 at 0.5 wt% acid at 25°C, 50°C and 90°C, respectively (little or no slagging risk). Increasing the acid loading to 1.0% only slightly decreased the measured alkali/acid ratio of remaining ash species. Lastly, the results presented here show that a water wash or dilute-acid preprocessing step can improve corn stover quality for pyrolysis, hydrothermal liquefaction and biopower.« less

Performance assessment of dilute-acid leaching to improve corn stover quality for thermochemical conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aston, John E.; Thompson, David N.; Westover, Tyler L.

Lignocellulosic biomass is a sustainable energy source that can help meet the increasing demand for biofuels in the United States. However, the quality and availability of such feedstocks greatly affects their suitability for downstream conversion. This work reports the effects of dilute-acid leaching at various solid loadings, temperatures and acid loadings on the quality of a traditional biochemical feedstock, corn stover, as a potential feedstock for thermochemical conversions. At 5 wt% solids, dilute-acid leaching was observed to effectively remove 97.3% of the alkali metals and alkaline earth metals that can negatively affect degradation pathways during pyrolysis and result in greatermore » yield of non-condensable gases. In addition, up to 98.4% of the chlorine and 88.8% of the phosphorus, which can cause equipment corrosion and foul upgrading catalysts, respectively, were removed. At 25°C in the absence of acid, only 6.8% of the alkali metals and alkaline earth metals were removed; however 88.0% of chloride was still removed. The ratio of alkaline/acidic ash species has been suggested to proportionately relate to slagging in biopower applications. The initial alkali/acid ratio of the ash species present in the untreated corn stover was 0.38 (significant slagging risk). At 5 wt% solids, this ratio was decreased to 0.18 (moderate slagging risk) at 0 wt% acid and 90°C, and was decreased to 0.07, 0.08 and 0.06 at 0.5 wt% acid at 25°C, 50°C and 90°C, respectively (little or no slagging risk). Increasing the acid loading to 1.0% only slightly decreased the measured alkali/acid ratio of remaining ash species. Lastly, the results presented here show that a water wash or dilute-acid preprocessing step can improve corn stover quality for pyrolysis, hydrothermal liquefaction and biopower.« less

Effect of training load structure on purine metabolism in middle-distance runners.

PubMed

Zieliński, Jacek; Kusy, Krzysztof; Rychlewski, Tadeusz

2011-09-01

There are no studies analyzing the effect of training loads on purine metabolism during long training periods. The study's purpose was to evaluate the effect of training load changes and subsequent detraining on purine metabolism in middle-distance runners during a 1-yr cycle. In four characteristic points of the training cycle, loads assigned to five intensity zones, pre- and postexercise plasma hypoxanthine (Hx) and uric acid, and erythrocyte Hx-guanine phosphoribosyltransferase (HGPRT) activity were determined in 11 male middle-distance runners at the national level, practicing competitive sport for 8.1 ± 0.3 yr and with a mean age of 22.3 ± 0.7 yr, body mass of 73.0 ± 3.4 kg, and body height of 180 ± 2.2 cm. In the competition phase (CP), training loads in aerobic compensation and threshold zones decreased by 65.4% and by 20.5%, respectively. At the same time, anaerobic training loads increased by 132.5% in the VO(2max) zone and by 74.6% in the lactic acid tolerance zone. Postexercise Hx decreased significantly in CP by 6.2 μmol·L(-1). and increased in the transition phase (TP) by 17.4 μmol·L(-1). Both pre- and postexercise HGPRT activity increased significantly in CP by 9.3 nmol·mg(-1)·h(-1). and by 4.9 nmol·mg(-1)·h(-1). , respectively, and decreased significantly in TP by 10.6 nmol·mg(-1)·h(-1). and by 12.0 nmol·mg(-1)·h(-1). , respectively. A significant uric acid increase of 54 μmol·L(-1). was revealed merely in TP. The effect of anaerobic training on purine metabolism is significant despite of a very short total duration of anaerobic loads. Elevated preexercise HGPRT activity in CP suggests adaptation changes consisting in a "permanent readiness" for purine salvage. The detraining in TP leads to reverse adaptation changes. Probably, plasma Hx concentration and erythrocyte HGPRT activity may be considered as a useful measure of training status.

Physicochemical interactions among α-eleostearic acid-loaded liposomes applied to the development of drug delivery systems

NASA Astrophysics Data System (ADS)

Nogueira, Alessandro Oliveira de Moraes; de Sousa, Robson Simplício; Pereira, Luiza Silveira; Mallmann, Christian; da Silva Ferreira, Ailton; Clementin, Rosilene Maria; de Lima, Vânia Rodrigues

2018-02-01

In this study, α-eleostearic acid-loaded (α-ESA-loaded) dimyristoylphosphatidylcholine (DMPC) liposomes had their physicochemical properties characterized by horizontal attenuated total reflectance Fourier transform infrared (HATR-FTIR) spectroscopy, nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). In vitro thiobarbituric acid reactive substance (TBARS) assays were performed to obtain preliminary information on the oxidative potential of the system. An α-ESA-promoted ordering effect in the lipid phosphate region was observed. It was associated with a rotation restriction due to an increase in the amount of lipid group hydrogen bonds. The fatty acid was responsible for the reduction in the degree of hydration of carbonyl groups located in the interfacial region of lipids. α-ESA disordered the DMPC methylene acyl chains by trans-gauche isomerization and increased its rotation rate. TBARS results showed pro-oxidant behavior on liposomes, induced by α-ESA. The discussion about the responses considered the degree of saturation of phosphatidylcholines and suggested that the α-ESA oxidative effects may be modulated by the liposome lipid composition. The versatility of liposomal carriers may be promising for the development of efficacious α-ESA-based drug delivery systems. Results described in this study contribute to the selection of adequate material to produce them.

High Dietary Protein Intake and Protein-Related Acid Load on Bone Health.

PubMed

Cao, Jay J

2017-12-01

Consumption of high-protein diets is increasingly popular due to the benefits of protein on preserving lean mass and controlling appetite and satiety. The paper is to review recent clinical research assessing dietary protein on calcium metabolism and bone health. Epidemiological studies show that long-term, high-protein intake is positively associated with bone mineral density and reduced risk of bone fracture incidence. Short-term interventional studies demonstrate that a high-protein diet does not negatively affect calcium homeostasis. Existing evidence supports that the negative effects of the acid load of protein on urinary calcium excretion are offset by the beneficial skeletal effects of high-protein intake. Future research should focus on the role and the degree of contribution of other dietary and physiological factors, such as intake of fruits and vegetables, in reducing the acid load and further enhancing the anabolic effects of protein on the musculoskeletal system.

Polyaspartic acid functionalized gold nanoparticles for tumor targeted doxorubicin delivery.

PubMed

Khandekar, Sameera V; Kulkarni, M G; Devarajan, Padma V

2014-01-01

In this paper, we present polyaspartic acid, a biodegradable polymer as a reducing and functionalizing agent for the synthesis of doxorubicin loaded gold nanoparticles by a green process. Gold nanoparticles were stable to electrolytes and pH. Secondary amino groups of polyaspartic acid enabled reduction of gold chloride to form gold nanoparticles of size 55 +/-10 nm, with face centered cubic crystalline structure as confirmed by UV, TEM, SAED and XRD studies. Cationic doxorubicin was readily loaded onto anionic polyaspartic acid gold nanoparticles by ionic complexation. Fluorescence studies confirmed doxorubicin loading while FTIR spectra confirmed ionic complexation. Doxorubicin loading onto polyaspartic acid gold nanoparticles was studied at doxorubicin/polyaspartic acid molar ratios 1:10 to 1:1. As the molar ratio tended to unity, although loading up to 60% was achieved, colloidal instability resulted and is attributed to effective covering of negative charges of polyaspartic acid. Stable doxorubicin loaded polyaspartic acid gold nanoparticles of 105 +/- 15.1 nm with doxorubicin loading of 23.85% w/w and zeta potential value of -28 +/- 0.77 mV were obtained at doxorubicin/polyaspartic acid molar ratio 1:10. Higher doxorubicin release rate from the doxorubicin loaded polyaspartic acid gold nanoparticles in an acid medium (i.e., pH 5.5) as compared to that in pH 7.4 and deionized water is a desirable characteristic for tumor targeted delivery. Enhanced cytotoxicity and 3 fold higher uptake of doxorubicin loaded polyaspartic acid gold nanoparticles as compared to doxorubicin solution were seen in MCF-7 breast cancer cells while polyaspartic acid gold nanoparticles revealed no cytotoxicity confirming safety. Prominent regression in tumor size in-vivo in fibrosarcoma tumor induced mouse model was observed upto 59 days with doxorubicin loaded polyaspartic acid gold nanoparticles while doxorubicin solution treated mice showed regrowth beyond 23rd day. Moreover, a decrease of body weight of 35% indicating severe toxicity with doxorubicin solution as compared to only 20% with gradual recovery after day 30 in case of doxorubicin loaded polyaspartic acid gold nanoparticles confirmed their lower toxicity and enhanced efficacy.

Characterization and properties of acetylated nanocrystalline cellulose (aNC) reinforced polylactic acid (PLA) polymer

NASA Astrophysics Data System (ADS)

Kasa, Siti Norbaya; Omar, Mohd Firdaus; Ismail, Ismarul Nizam

2017-12-01

Nanocrystalline cellulose (NCC) was synthesized from banana stem through strong acid hydrolysis with measured length of approximately 287.0 ± 56.4 nm and diameter of 26.6 ± 4.8 nm. Modification of NCC was carried by acetylation reaction in order to increase the compatibility during reinforcement with polylactic acid (PLA) polymer. The reinforcing effect towards morphology, crystallinity, mechanical and thermal properties of bio-nanocomposites was investigated. Scanning Electron Microscope (SEM) micrograph reveals the uniform dispersion achieved at 1 %, 3 % and 5% aNC loading while agglomeration was found at 7 % aNC loading. Disappearance of crystallinity peak at 2θ = 22.7⁰ for low aNC loading during elemental analysis using X-Ray Diffraction (XRD) indicates the proper dispersion of aNC in PLA polymer. From the tensile test, 1 % aNC loading gives the highest mechanical properties of bio-nanocomposite film with 82.71 %, 118.7 % and 24.18 % increment in tensile strength, tensile modulus and elongation at break. However, 7 % aNC loading gives the highest increment in TGA of aNC-PLA nanocomposites which is from 310 °C to 320 °C.

Butanol Dehydration over V₂O₅-TiO₂/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition.

PubMed

Choi, Hyeonhee; Bae, Jung-Hyun; Kim, Do Heui; Park, Young-Kwon; Jeon, Jong-Ki

2013-04-29

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO₂-V₂O₅/MCM-41 catalysts were analyzed using XRF, BET, NH₃-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO₂/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH₃-TPD and Py-IR results indicated that weak acid sites were produced over the TiO₂/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V₂O₅(12.1)-TiO₂/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

Estimates of critical acid loads and exceedances for forest soils across the conterminous United States.

PubMed

McNulty, Steven G; Cohen, Erika C; Moore Myers, Jennifer A; Sullivan, Timothy J; Li, Harbin

2007-10-01

Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A pollutant load in excess of a critical acid load is termed exceedance. This study combined a simple mass balance equation with national-scale databases to estimate critical acid load and exceedance for forest soils at a 1-km(2) spatial resolution across the conterminous US. This study estimated that about 15% of US forest soils are in exceedance of their critical acid load by more than 250eqha(-1)yr(-1), including much of New England and West Virginia. Very few areas of exceedance were predicted in the western US.

Effect of phosphoric acid on the morphology and tensile properties of halloysite-polyurethane composites

NASA Astrophysics Data System (ADS)

Gaaz, Tayser Sumer; Luaibi, Hasan Mohammed; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.

2018-06-01

The high aspect ratio of nanoscale reinforcements enhances the tensile properties of pure polymer matrix. The composites were first made by adding halloysite nanotubes (HNTs) at low weight percentages of 1, 2, and 3 wt% to thermoplastic polyurethane (TPU). Then, HNTs were phosphoric acid-treated before adding to TPU at same weight percentage to create phosphoric acid HNTs-TPU composites. The samples were fabricated using injection moulding. The HNTs-TPU composites were characterized according to the tensile properties including tensile strength, tensile strain and Young's modulus. The loading has shown its highest tensile values at 2 wt% HNTs loading and same findings are shown with the samples that treated with phosphoric acid. The tensile strength increased to reach 24.65 MPa compare with the 17.7 MPa of the neat TPU showing about 26% improvement. For the phosphoric acid-treated composites, the improvement has reached 35% compared to the neat sample. Regarding the tensile stain, the improvement was about 83% at 2 wt% HNTs loading. For Young's modulus, the results obtained in this study have shown that Young's modulus is linearly improved with either the loading content or the phosphoric acid treated achieving its highest values at 3 wt% HNTs of 14.53 MPa and 16.27 MPa for untreated and treated, respectively. FESEM results showed that HNTs were well dispersed in TPU matrix. Thus, HNTs-TPU has improved tensile properties compared with pure TPU due to the addition of nanofiller.

[The pyretroind pesticides lambda-cigalothrines influence on composition of free aminoacids in tissue of fish in Alazani River].

PubMed

Dzhikiia, G M; Mchedluri, T T; Nikolaĭshvili, M I; Zurabishvili, Z A; Iordanishvili, G S

2011-12-01

The aim of the research was to study toxic effect of lambda-cigalothrin, on quantitative contents of free amino acid in muscle, liver and in brain of fishes in r. Alazani. It was found that under the action of lambda-cigalothrin total amount of free amino acid in fish's tissue was increasing, contents of glycine, asparagine and glutamine acids, alanine and cysteine also increased. Increasing of glutamine and asparagines acids content in muscle and liver of fish goes with the dissimilation of other amino acids through the process of their deaminization by glutamate dehydrogenation system. Increasing the alanine content is indicative of reinforcement of transamination processes. Decrease of phenylalanine, valine, glycine and the other amino acids content is explained by reinforcement of amino acids catabolism in condition of pesticide load, as it occurs in condition of fishes' intoxication by phenols.

Assessment of potential aluminum chelators in an octanol/aqueous system and in the aluminum-loaded rabbit.

PubMed

Yokel, R A; Kostenbauder, H B

1987-11-01

Aluminum (Al) solubilization from Al borate and its distribution in an octanol/aqueous system (Do/w) were determined in the absence and presence of 12 potential Al chelators. Citrate, N,N'-bis-(2-hydroxybenzyl)ethylenediamine- N,N'-diacetic acid (HBED), cyclohexane-1,2-diaminotetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), desferrioxamine, and ethylenediamine-N,N'-bis(2-dihydroxyphenylacetic acid) (EDDHA) were 55 to over 100% efficient in solubilizing equimolar amounts of Al. Tetracycline, EDTA, and 2,3-dihydroxybenzoic acid (DHBA) were less than 20% efficient. 1,4-Dioxane and fluoride were ineffective. The Do/w of Al averaged 0.005. The Do/w of the Al.chelator complex was generally less than that of Al, except for HBED and tetracycline (0.04 and 0.96, respectively). The Do/w of DHBA, desferrioxamine, EDDHA, and HBED were not influenced by Al, but tetracycline became more lipophilic. These compounds were tested for their ability to increase urinary Al excretion in Al-loaded rabbits. Chelators were given po weekly beginning 2 weeks after Al loading. Urine was obtained hourly from 3 hr prior to 6 hr after chelator administration and analyzed for Al. Fluoride and tetracycline (450 and 4500 mumol/kg) and citrate, NTA, EDTA, CDTA, DTPA, DHBA, HBED, and 1,4-dioxane (150 and 1500 mumol/kg) were ineffective. Following HBED administration, some of the Al-loaded rabbits died, presumably due to redistribution of Al within the rabbit. Following DTPA administration, some of the Al-loaded rabbits died, presumably due to DTPA. Oral EDDHA (1500 mumol/kg) significantly increased urinary Al excretion. EDDHA and desferrioxamine (150 mumol/kg) were administered by po, sc, and iv routes and were found to have comparable potency. The in vitro results may explain some of the in vivo findings. The in vitro methods may be useful to screen out compounds with no chelation potential. EDDHA-like compounds may have potential as alternatives to desferrioxamine in the prevention or treatment of Al accumulation and Al-induced toxicity.

Effects of particle size, helium gas pressure and microparticle dose on the plasma concentration of indomethacin after bombardment of indomethacin-loaded poly-L-lactic acid microspheres using a Helios gun system.

PubMed

Uchida, Masaki; Natsume, Hideshi; Kobayashi, Daisuke; Sugibayashi, Kenji; Morimoto, Yasunori

2002-05-01

We investigated the effects of the particle size of indomethacin-loaded poly-L-lactic acid microspheres (IDM-loaded PLA MS), the helium pressure used to accelerate the particles, and the bombardment dose of PLA MS on the plasma concentration of IDM after bombarding with IDM-loaded PLA MS of different particle size ranges, 20-38, 44-53 and 75-100 microm, the abdomen of hairless rats using the Helios gene gun system (Helios gun system). Using larger particles and a higher helium pressure, produced an increase in the plasma IDM concentration and the area under the plasma concentration-time curve (AUC) and resultant F (relative bioavailability with respect to intracutaneous injection) of IDM increased by an amount depending on the particle size and helium pressure. Although a reduction in the bombardment dose led to a decrease in C(max) and AUC, F increased on decreasing the bombardment dose. In addition, a more efficient F was obtained after bombarding with IDM-loaded PLA MS of 75-100 microm in diameter at each low dose in different sites of the abdomen compared with that after bolus bombardment with a high dose (dose equivalent). These results suggest that the bombardment injection of drug-loaded microspheres by the Helios gun system is a very useful tool for delivering a variety of drugs in powder form into the skin and systemic circulation.

Catalytic performance of strong acid catalyst: Methyl modified SBA-15 loaded perfluorinated sulfonic acid obtained by the waste perfluorinated sulfonic acid ion exchange membrane

NASA Astrophysics Data System (ADS)

Jiang, Tingshun; Huang, Qiuyan; Li, Yingying; Fang, Minglan; Zhao, Qian

2018-02-01

Mesoporous molecular sieve (SBA-15) was modified using the trimethylchlorosilane as functional agent and the silylation SBA-15 mesoporous material was prepared in this work. The alcohol solution of perfluorinated sulfonic acid dissolved from the waste perfluorinated sulfonic acid ion exchange membrane (PFSIEM) was loaded onto the resulting mesoporous material by the impregnation method and their physicochemical properties were characterized by FT-IR, N2-physisorption, XRD, TG-DSC and TEM. The catalytic activities of these synthesized solid acid catalysts were evaluated by alkylation of phenol with tert-butyl alcohol. The influence of reaction temperature, weight hour space velocity (WHSV) and reaction time on the phenol conversion and product selectivity were assessed by means of a series of experiments. The results showed that with the increase of the active component of the catalyst, these catalysts still remained good mesoporous structure, but the mesoporous ordering decreased to some extent. These catalysts exhibited good catalytic performance for the alkylation of phenol with tert-butanol. The maximum phenol conversion of 89.3% with 70.9% selectivity to 4-t-butyl phenol (4-TBP) was achieved at 120 °C and the WHSV is 4 h-1. The methyl group was loaded on the surface of the catalyst by trimethylchlorosilane. This is beneficial to retard the deactivation of the catalyst. In this work, the alkylation of phenol with tert-butyl alcohol were carried out using the methyl modified SBA-15 mesoporous materials loaded perfluorinated sulfonic acid as catalysts. The results show that the resulting catalyst exhibited high catalytic activity.

Hydroisomerization of n-dodecane over Pt/Al-MCM-48 catalysts.

PubMed

Yun, Soyoung; Park, Young-Kwon; Jeong, Soon-Yong; Han, Jeongsik; Jeon, Jong-Ki

2014-04-01

The objective of this study is to evaluate the catalytic potential of Pt/Al-MCM-48 catalysts in hydroisomerization of n-dodecane. The effects of the Si/Al ratio and platinum loading on the acid characteristics of Al-MCM-48 and the catalytic performance in n-dodecane hydroisomerization were analyzed. The catalysts were characterized by X-ray diffraction, nitrogen adsorption, infrared spectroscopy of pyridine adsorption, and temperature programmed desorption of ammonia. The number of weak strength acid sites on Al-MCM-48 increased with 0.5 wt% platinum loading. The weak strength acid sites of Pt/Al-MCM-48 catalysts were ascribed to Lewis acid sites, which can be confirmed by NH3-TPD and FTIR spectra of pyridine adsorption. Iso-dodecane can be produced with high selectivity in n-dodecane hydrosisomerization over Pt/Al-MCM-48 catalysts. This is attributed to the mild acidic properties of Pt/Al-MCM-48 catalysts.

Acidogenesis and Two-Phase Codigestion of Fats, Oils, and Greases and Municipal Biosolids.

PubMed

Varin, Ross; Novak, John; Bott, Charles

2016-11-01

  Acidogenic codigestion of fats, oils, and greases (FOG) was studied using suspended growth sludge digesters operated as batch fed reactors that were fed twice daily. The digesters were maintained at a 2-day retention time and at 37 °C to mimic the acid phase of an acid-gas digestion system. As FOG loading rates increased, volatile fatty acid (VFA) production was found to increase, although the percentage of VFA production compared to theoretical values decreased exponentially to just 20% at the highest loading rates. FOG matter was found to have accumulated in the reactor vessel in semi-solid balls that floated near the liquid surface. Two-phase codigestion of FOG was studied at 37 °C using Continuously Stirred Tank Reactors (CSTRs) as acid phase digesters (APD) operated with 2-day retention times, followed by gas phase digesters (GPD) with 15-day retention times. The two-phase systems were compared by FOG addition to the APD versus GPD. FOG addition to the APD resulted in 88% destruction of LCFAs, whereas FOG addition to the GPD resulted in 95% destruction of LCFAs. Accumulated LCFAs were found in the APD receiving FOG and were primarily composed palmitic acid (16:0), followed by oleic acid (18:1) and stearic acid (18:0).

Doxorubicin-loaded glycyrrhetinic acid modified recombinant human serum albumin nanoparticles for targeting liver tumor chemotherapy.

PubMed

Qi, Wen-Wen; Yu, Hai-Yan; Guo, Hui; Lou, Jun; Wang, Zhi-Ming; Liu, Peng; Sapin-Minet, Anne; Maincent, Philippe; Hong, Xue-Chuan; Hu, Xian-Ming; Xiao, Yu-Ling

2015-03-02

Due to overexpression of glycyrrhetinic acid (GA) receptor in liver cancer cells, glycyrrhetinic acid modified recombinant human serum albumin (rHSA) nanoparticles for targeting liver tumor cells may result in increased therapeutic efficacy and decreased adverse effects of cancer therapy. In this study, doxorubicin (DOX) loaded and glycyrrhetinic acid modified recombinant human serum albumin nanoparticles (DOX/GA-rHSA NPs) were prepared for targeting therapy for liver cancer. GA was covalently coupled to recombinant human serum albumin nanoparticles, which could efficiently deliver DOX into liver cancer cells. The resultant GA-rHSA NPs exhibited uniform spherical shape and high stability in plasma with fixed negative charge (∼-25 mV) and a size about 170 nm. DOX was loaded into GA-rHSA NPs with a maximal encapsulation efficiency of 75.8%. Moreover, the targeted NPs (DOX/GA-rHSA NPs) showed increased cytotoxic activity in liver tumor cells compared to the nontargeted NPs (DOX/rHSA NPs, DOX loaded recombinant human serum albumin nanoparticles without GA conjugating). The targeted NPs exhibited higher cellular uptake in a GA receptor-positive liver cancer cell line than nontargeted NPs as measured by both flow cytometry and confocal laser scanning microscopy. Biodistribution experiments showed that DOX/GA-rHSA NPs exhibited a much higher level of tumor accumulation than nontargeted NPs at 1 h after injection in hepatoma-bearing Balb/c mice. Therefore, the DOX/GA-rHSA NPs could be considered as an efficient nanoplatform for targeting drug delivery system for liver cancer.

Effects of Lewis acidity of metal oxide promoters on the activity and selectivity of Co-based Fischer–Tropsch synthesis catalysts

DOE PAGES

Johnson, Gregory R.; Bell, Alexis T.

2016-03-31

Metal oxides of Ce, Gd, La, Mn, and Zr were investigated as promoters for improving the activity and selectivity of Co-based FTS catalysts. The extent to which these promoters decrease the selectivity toward CH 4 and increase the selectivity toward C 5+ hydrocarbons was found to depend on both the loading and the composition of the oxide promoter. Elemental mapping by STEM-EDS revealed that the propensity for a given metal oxide to associate with Co affects the sensitivity of the product distribution to changes in promoter loading. For all promoters, a sufficiently high loading resulted in the product distributions becomingmore » insensitive to further increases in promoter loading, very likely due to the formation of a half monolayer of promoter oxide over the Co surface. Simulations suggest that the fraction of Co active sites that are adjacent to the promoter moieties approaches unity at this degree of coverage. The oxidation state of the promoter metal cation under reaction conditions, determined by in situ XANES measurements, was used to calculate relative Lewis acidity of the promoter metal cation. We found a strong positive correlation between the C 5+ product selectivity and the Lewis acidity of the promoter metal cations, suggesting that the promotional effects are a consequence of Lewis acid-base interactions between the reaction intermediates and the promoter metal cations. Rate data obtained at different pressures were used to estimate the apparent rate coefficient and the CO adsorption constant appearing in the Langmuir-Hinshelwood expression that describes the CO consumption kinetics for both unpromoted and the metal oxide-promoted catalysts. Both parameters exhibited positive correlations with the promoter Lewis acidity. Our results are consistent with the hypothesis that the metal cations of the promoter act as Lewis acids that interact with the O atom of adsorbed CO to facilitate CO adsorption and dissociation.« less

Effects of a gradually increased load of fish waste silage in co-digestion with cow manure on methane production.

PubMed

Solli, Linn; Bergersen, Ove; Sørheim, Roald; Briseid, Tormod

2014-08-01

This study examined the effects of an increased load of nitrogen-rich organic material on anaerobic digestion and methane production. Co-digestion of fish waste silage (FWS) and cow manure (CM) was studied in two parallel laboratory-scale (8L effective volume) semi-continuous stirred tank reactors (designated R1 and R2). A reactor fed with CM only (R0) was used as control. The reactors were operated in the mesophilic range (37°C) with a hydraulic retention time of 30 days, and the entire experiment lasted for 450 days. The rate of organic loading was raised by increasing the content of FWS in the feed stock. During the experiment, the amount (volume%) of FWS was increased stepwise in the following order: 3% - 6% - 13% - 16%, and 19%. Measurements of methane production, and analysis of volatile fatty acids, ammonium and pH in the effluents were carried out. The highest methane production from co-digestion of FWS and CM was 0.400 L CH4 gVS(-1), obtained during the period with loading of 16% FWS in R2. Compared to anaerobic digestion of CM only, the methane production was increased by 100% at most, when FWS was added to the feed stock. The biogas processes failed in R1 and R2 during the periods, with loadings of 16% and 19% FWS, respectively. In both reactors, the biogas processes failed due to overloading and accumulation of ammonia and volatile fatty acids. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cardiorespiratory parameters in draught horses before and after short term draught work pulling loads.

PubMed

Pérez, R; Recabarren, S E; Mora, G; Jara, C; Quijada, G; Hetz, E

1992-04-01

In order to establish the relationship between draught force and cardiorespiratory responses to exercise heart rate (HR), respiratory rate (RR), arterial and venous blood gases, pH, hemoglobin concentration and temperature were measured in five draught horses during rest, immediately after exercise and 30 min post-exercise under field conditions. A wagon equipped with an odometer and a hydraulic dynamometer was used for measuring distance and draught force. The wagon was loaded with 946 kg for the low load, 1,979 kg for the medium load and 2,994 kg for the high load, and drawn for a distance of 1,500 m. Draught force and load weight were linearly related. The response of the draught horse to low and medium load exercise was characterized by a moderate increase in HR, RR and temperature with no significant changes in arterial blood gases and pH. An increase in HR, RR and temperature was observed, whereas no changes in arterial PO2 and increases in venous PO2 were noticed after high load exercise. Slight increase in venous lactic acid concentration as a result of high load exercise was observed, suggesting that some anaerobic work was performed. However this was insufficient to produce changes in blood pH. The increase in metabolic requirements during the three levels of draught exercise was associated with increases in arterial hemoglobin concentration and oxygen content of blood.

Acid loading test (pH)

MedlinePlus

... medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the kidneys to send ...

Enhanced Gene and siRNA Delivery by Polycation-Modified Mesoporous Silica Nanoparticles Loaded with Chloroquine

PubMed Central

Bhattarai, Shanta Raj; Muthuswamy, Elayaraja; Wani, Amit; Brichacek, Michal; Castañeda, Antonio L.; Brock, Stephanie L.

2014-01-01

Purpose To prepare mesoporous silica-based delivery systems capable of simultaneous delivery of drugs and nucleic acids. Methods The surface of mesoporous silica nanoparticles (MSN) was modified with poly(ethylene glycol) (PEG) and poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA) or poly (2-(diethylamino)ethylmethacrylate) (PDEAEMA). The particles were then loaded with a lysosomotropic agent chloroquine (CQ) and complexed with plasmid DNA or siRNA. The ability of the synthesized particles to deliver combinations of CQ and nucleic acids was evaluated using luciferase plasmid DNA and siRNA targeting luciferase and GAPDH. Results The results show a slow partial MSN dissolution to form hollow silica nanoparticles in aqueous solution. The biological studies show that polycation-modified MSN are able to simultaneously deliver CQ with DNA and siRNA. The co-delivery of CQ and the nucleic acids leads to a significantly increased transfection and silencing activity of the complexes compared with MSN not loaded with CQ. Conclusion PEGylated MSN modified with polycations are promising delivery vectors for combination drug/nucleic acid therapies. PMID:20730557

Experimental identification of the active sites in pyrolyzed carbon-supported cobalt-polypyrrole-4-toluenesulfinic acid as electrocatalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Sha, Hao-Dong; Yuan, Xianxia; Li, Lin; Ma, Zhong; Ma, Zi-Feng; Zhang, Lei; Zhang, Jiujun

2014-06-01

A series of carbon supported cobalt-polypyrrole-4-toluenesulfinic acid have been pyrolyzed in an argon atmosphere at 800 °C, then structurally characterized and electrochemically evaluated as oxygen reduction reaction (ORR) catalysts in aqueous 0.5 M sulfuric acid. The structures are cobalt bonded to nitrogen species (Co-Nx) along with metallic cobalt and cobalt oxide. When the cobalt loading in the compound is less than 1.0 wt%, the predominate form is Co-Nx, when the loading is higher than 1.0 wt%, metallic Co and Co oxide particles co-exist with the Co-Nx compound. At a Co loading of ∼1.0 wt%, the catalyst gives the best ORR activity. Both metallic Co and Co oxide are not active for catalyzing ORR, and block the catalytically active Co-Nx species from the surface and reduce the catalytic activity since the diffusion limiting current density on a rotating disk electrode (RDE) increases when the electrode blocking agents are washed away with acid.

A conceptual framework: redifining forests soil's critical acid loads under a changing climate

Treesearch

Steven G. McNulty; Johnny L. Boggs

2010-01-01

Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it...

The Cu2+-nitrilotriacetic acid complex improves loading of α-helical double histidine site for precise distance measurements by pulsed ESR

NASA Astrophysics Data System (ADS)

Ghosh, Shreya; Lawless, Matthew J.; Rule, Gordon S.; Saxena, Sunil

2018-01-01

Site-directed spin labeling using two strategically placed natural histidine residues allows for the rigid attachment of paramagnetic Cu2+. This double histidine (dHis) motif enables extremely precise, narrow distance distributions resolved by Cu2+-based pulsed ESR. Furthermore, the distance measurements are easily relatable to the protein backbone-structure. The Cu2+ ion has, till now, been introduced as a complex with the chelating agent iminodiacetic acid (IDA) to prevent unspecific binding. Recently, this method was found to have two limiting concerns that include poor selectivity towards α-helices and incomplete Cu2+-IDA complexation. Herein, we introduce an alternative method of dHis-Cu2+ loading using the nitrilotriacetic acid (NTA)-Cu2+ complex. We find that the Cu2+-NTA complex shows a four-fold increase in selectivity toward α-helical dHis sites. Furthermore, we show that 100% Cu2+-NTA complexation is achievable, enabling precise dHis loading and resulting in no free Cu2+ in solution. We analyze the optimum dHis loading conditions using both continuous wave and pulsed ESR. We implement these findings to show increased sensitivity of the Double Electron-Electron Resonance (DEER) experiment in two different protein systems. The DEER signal is increased within the immunoglobulin binding domain of protein G (called GB1). We measure distances between a dHis site on an α-helix and dHis site either on a mid-strand or a non-hydrogen bonded edge-strand β-sheet. Finally, the DEER signal is increased twofold within two α-helix dHis sites in the enzymatic dimer glutathione S-transferase exemplifying the enhanced α-helical selectivity of Cu2+-NTA.

Omega 3 Chia seed loading as a means of carbohydrate loading.

PubMed

Illian, Travis G; Casey, Jason C; Bishop, Phillip A

2011-01-01

The purpose of this study was to determine if Omega 3 Chia seed loading is a viable option for enhancing sports performance in events lasting >90 minutes and allow athletes to decrease their dietary intake of sugar while increasing their intake of Omega 3 fatty acids. It has been well documented that a high dietary carbohydrate (CHO) intake for several days before competition is known to increase muscle glycogen stores resulting in performance improvements in events lasting >90 minutes. This study compared performance testing results between 2 different CHO-loading treatments. The traditional CHO-loading treatment served as the control (100% cals from Gatorade). The Omega 3 Chia drink (50% of calories from Greens Plus Omega 3 Chia seeds, 50% Gatorade) served as the Omega 3 Chia loading drink. Both CHO-loading treatments were based on the subject's body weight and were thus isocaloric. Six highly trained male subjects V(O2)max 47.8-84.2 ml · kg(-1); mean (SD) of V(O2)max 70.3 ml · kg(-1) (13.3) performed a 1-hour run at ∼65% of their V(O2)max on a treadmill, followed by a 10k time trial on a track. There were 2 trials in a crossover counterbalanced repeated-measures design with a 2-week washout between testing sessions to allow the participants to recover from the intense exercise and any effects of the treatment. There was no statistical difference (p = 0.83) between Omega 3 Chia loading (mean 10k time = 37 minutes 49 seconds) and CHO loading (mean = 37 minutes 43 seconds). Under our conditions, Omega 3 Chia loading appears a viable option for enhancing performance for endurance events lasting >90 minutes and allows athletes to decrease their dietary intake of sugar while increasing their intake of Omega 3 fatty acids but offered no performance advantages.

Diet, evolution and aging--the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet.

PubMed

Frassetto, L; Morris, R C; Sellmeyer, D E; Todd, K; Sebastian, A

2001-10-01

Theoretically, we humans should be better adapted physiologically to the diet our ancestors were exposed to during millions of years of hominid evolution than to the diet we have been eating since the agricultural revolution a mere 10,000 years ago, and since industrialization only 200 years ago. Among the many health problems resulting from this mismatch between our genetically determined nutritional requirements and our current diet, some might be a consequence in part of the deficiency of potassium alkali salts (K-base), which are amply present in the plant foods that our ancestors ate in abundance, and the exchange of those salts for sodium chloride (NaCl), which has been incorporated copiously into the contemporary diet, which at the same time is meager in K-base-rich plant foods. Deficiency of K-base in the diet increases the net systemic acid load imposed by the diet. We know that clinically-recognized chronic metabolic acidosis has deleterious effects on the body, including growth retardation in children, decreased muscle and bone mass in adults, and kidney stone formation, and that correction of acidosis can ameliorate those conditions. Is it possible that a lifetime of eating diets that deliver evolutionarily superphysiologic loads of acid to the body contribute to the decrease in bone and muscle mass, and growth hormone secretion, which occur normally with age? That is, are contemporary humans suffering from the consequences of chronic, diet-induced low-grade systemic metabolic acidosis? Our group has shown that contemporary net acid-producing diets do indeed characteristically produce a low-grade systemic metabolic acidosis in otherwise healthy adult subjects, and that the degree of acidosis increases with age, in relation to the normally occurring age-related decline in renal functional capacity. We also found that neutralization of the diet net acid load with dietary supplements of potassium bicarbonate (KHCO3) improved calcium and phosphorus balances, reduced bone resorption rates, improved nitrogen balance, and mitigated the normally occurring age-related decline in growth hormone secretion--all without restricting dietary NaCl. Moreover, we found that co-administration of an alkalinizing salt of potassium (potassium citrate) with NaCl prevented NaCl from increasing urinary calcium excretion and bone resorption, as occurred with NaCl administration alone. Earlier studies estimated dietary acid load from the amount of animal protein in the diet, inasmuch as protein metabolism yields sulfuric acid as an end-product. In cross-cultural epidemiologic studies, Abelow found that hip fracture incidence in older women correlated with animal protein intake, and they suggested a causal relation to the acid load from protein. Those studies did not consider the effect of potential sources of base in the diet. We considered that estimating the net acid load of the diet (i. e., acid minus base) would require considering also the intake of plant foods, many of which are rich sources of K-base, or more precisely base precursors, substances like organic anions that the body metabolizes to bicarbonate. In following up the findings of Abelow et al., we found that plant food intake tended to be protective against hip fracture, and that hip fracture incidence among countries correlated inversely with the ratio of plant-to-animal food intake. These findings were confirmed in a more homogeneous population of white elderly women residents of the U.S. These findings support affirmative answers to the questions we asked above. Can we provide dietary guidelines for controlling dietary net acid loads to minimize or eliminate diet-induced and age-amplified chronic low-grade metabolic acidosis and its pathophysiological sequelae. We discuss the use of algorithms to predict the diet net acid and provide nutritionists and clinicians with relatively simple and reliable methods for determining and controlling the net acid load of the diet. A more difficult question is what level of acidosis is acceptable. We argue that any level of acidosis may be unacceptable from an evolutionarily perspective, and indeed, that a low-grade metabolic alkalosis may be the optimal acid-base state for humans.

Comparison of the impacts of acid and nitrogen additions on carbon fluxes in European conifer and broadleaf forests.

PubMed

Oulehle, Filip; Tahovská, Karolina; Chuman, Tomáš; Evans, Chris D; Hruška, Jakub; Růžek, Michal; Bárta, Jiří

2018-07-01

Increased reactive nitrogen (N) loadings to terrestrial ecosystems are believed to have positive effects on ecosystem carbon (C) sequestration. Global "hot spots" of N deposition are often associated with currently or formerly high deposition of sulphur (S); C fluxes in these regions might therefore not be responding solely to N loading, and could be undergoing transient change as S inputs change. In a four-year, two-forest stand (mature Norway spruce and European beech) replicated field experiment involving acidity manipulation (sulphuric acid addition), N addition (NH 4 NO 3 ) and combined treatments, we tested the extent to which altered soil solution acidity or/and soil N availability affected the concentration of soil dissolved organic carbon (DOC), soil respiration (Rs), microbial community characteristics (respiration, biomass, fungi and bacteria abundances) and enzyme activity. We demonstrated a large and consistent suppression of soil water DOC concentration driven by chemical changes associated with increased hydrogen ion concentrations under acid treatments, independent of forest type. Soil respiration was suppressed by sulphuric acid addition in the spruce forest, accompanied by reduced microbial biomass, increased fungal:bacterial ratios and increased C to N enzyme ratios. We did not observe equivalent effects of sulphuric acid treatments on Rs in the beech forest, where microbial activity appeared to be more tightly linked to N acquisition. The only changes in C cycling following N addition were increased C to N enzyme ratios, with no impact on C fluxes (either Rs or DOC). We conclude that C accumulation previously attributed solely to N deposition could be partly attributable to their simultaneous acidification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method for digesting spent ion exchange resins and recovering actinides therefrom using microwave radiation

DOEpatents

Maxwell, III, Sherrod L.; Nichols, Sheldon T.

1999-01-01

The present invention relates to methods for digesting diphosphonic acid substituted cation exchange resins that have become loaded with actinides, rare earth metals, or heavy metals, in a way that allows for downstream chromatographic analysis of the adsorbed species without damage to or inadequate elution from the downstream chromatographic resins. The methods of the present invention involve contacting the loaded diphosphonic acid resin with concentrated oxidizing acid in a closed vessel, and irradiating this mixture with microwave radiation. This efficiently increases the temperature of the mixture to a level suitable for digestion of the resin without the use of dehydrating acids that can damage downstream analytical resins. In order to ensure more complete digestion, the irradiated mixture can be mixed with hydrogen peroxide or other oxidant, and reirradiated with microwave radiation.

Wear of human enamel: a quantitative in vitro assessment.

PubMed

Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

1998-12-01

Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

Intracellular pH Regulation in Cultured Astrocytes from Rat Hippocampus

PubMed Central

Bevensee, Mark O.; Weed, Regina A.; Boron, Walter F.

1997-01-01

We studied the regulation of intracellular pH (pHi) in single cultured astrocytes passaged once from the hippocampus of the rat, using the dye 2′,7′-biscarboxyethyl-5,6-carboxyfluorescein (BCECF) to monitor pHi. Intrinsic buffering power (βI) was 10.5 mM (pH unit)−1 at pHi 7.0, and decreased linearly with pHi; the best-fit line to the data had a slope of −10.0 mM (pH unit)−2. In the absence of HCO3 −, pHi recovery from an acid load was mediated predominantly by a Na-H exchanger because the recovery was inhibited 88% by amiloride and 79% by ethylisopropylamiloride (EIPA) at pHi 6.05. The ethylisopropylamiloride-sensitive component of acid extrusion fell linearly with pHi. Acid extrusion was inhibited 68% (pHi 6.23) by substituting Li+ for Na+ in the bath solution. Switching from a CO2/HCO3 −-free to a CO2/HCO3 −-containing bath solution caused mean steady state pHi to increase from 6.82 to 6.90, due to a Na+-driven HCO3 − transporter. The HCO3 −-induced pHi increase was unaffected by amiloride, but was inhibited 75% (pHi 6.85) by 400 μM 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS), and 65% (pHi 6.55–6.75) by pretreating astrocytes for up to ∼6.3 h with 400 μM 4-acetamide-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS). The CO2/HCO3 −-induced pHi increase was blocked when external Na+ was replaced with N-methyl-d-glucammonium (NMDG+). In the presence of HCO3 −, the Na+-driven HCO3 − transporter contributed to the pHi recovery from an acid load. For example, HCO3 − shifted the plot of acid-extrusion rate vs. pHi by 0.15–0.3 pH units in the alkaline direction. Also, with Na-H exchange inhibited by amiloride, HCO3 − increased acid extrusion 3.8-fold (pHi 6.20). When astrocytes were acid loaded in amiloride, with Li+ as the major cation, HCO3 − failed to elicit a substantial increase in pHi. Thus, Li+ does not appear to substitute well for Na+ on the HCO3 − transporter. We conclude that an amiloride-sensitive Na-H exchanger and a Na+-driven HCO3 − transporter are the predominant acid extruders in astrocytes. PMID:9379175

ANION EXCHANGE METHOD FOR SEPARATION OF METAL VALUES

DOEpatents

Hyde, E.K.; Raby, B.A.

1959-02-10

A method is described for selectively separating radium, bismuth, poloniums and lead values from a metallic mixture of thc same. The mixture is dissolved in aqueous hydrochloric acid and the acidity is adjusted to between 1 to 2M in hydrochloric acid to form the anionic polychloro complexes of polonium and bismuth. The solution is contacted with a first anion exchange resin such as strong base quaternary ammonia type to selectively absorb the polonium and bismuth leaving the radium and lead in the effluent. The effluent, after treatment in hydrochloric acid to increase the hydrochloric acid concentration to 6M is contacted with a second anion exchange iesin of the same type as the above to selectively adsorb the lead leaving the radium in the effluent. Radium is separately recovered from the effluent from the second exchange column. Lead is stripped from the loaded resin of the second column by treatment with 3M hydrochloric acid solution. The loaded resin of the first column is washed with 8M hydrochloric acid solution to recover bismuth and then treated with strong nitric acid solution to recover polonium.

Vitamin-loaded electrospun cellulose acetate nanofiber mats as transdermal and dermal therapeutic agents of vitamin A acid and vitamin E.

PubMed

Taepaiboon, Pattama; Rungsardthong, Uracha; Supaphol, Pitt

2007-09-01

The present contribution reports the use of mats of electrospun cellulose acetate (CA; acetyl content=39.8%; Mw=30,000 Da) nanofibers as carriers for delivery of the model vitamins, all-trans retinoic acid or vitamin A acid (Retin-A) and alpha-tocopherol or vitamin E (Vit-E). The amounts of Vit-E and Retin-A loaded in the base CA solution [17% w/v in 2:1 v/v acetone/N,N-dimethylacetamide (DMAc)] were 5 and 0.5 wt% (based on the weight of CA), respectively. Cross-sectionally round and smooth fibers were obtained. The average diameters of these fibers ranged between 247 and 265 nm. The total immersion of the vitamin-loaded as-spun CA fiber mats in the acetate buffer solutions containing either 0.5 vol % Tween 80 or 0.5 vol % Tween 80 and 10 vol % methanol was used to arrive at the cumulative release of the vitamins from the fiber mat samples. The same was also conducted on the vitamin-loaded solution-cast CA films for comparison. In most cases, the vitamin-loaded as-spun fiber mats exhibited a gradual and monotonous increase in the cumulative release of the vitamins over the test periods (i.e., 24 h for Vit-E-loaded samples and 6 h for Retin-A-loaded ones), while the corresponding as-cast films exhibited a burst release of the vitamins.

Anacardic acid enhances the anticancer activity of liposomal mitoxantrone towards melanoma cell lines – in vitro studies

PubMed Central

Legut, Mateusz; Lipka, Dominik; Filipczak, Nina; Piwoni, Adriana; Kozubek, Arkadiusz; Gubernator, Jerzy

2014-01-01

This paper describes a novel formulation of antineoplastic drug: mitoxantrone loaded into liposomal carriers enriched with encapsulated anacardic acid in the liposomal bilayer using a vitamin C gradient. Anacardic acid is a potent epigenetic agent with anticancer activity. This is the first liposomal formulation to combine an actively encapsulated drug and anacardic acid. The liposomes were characterized in terms of basic parameters, such as size, zeta potential, optimal drug-to-lipid ratio, loading time and temperature, and stability at 4°C and in human plasma in vitro. The formulation was found to be stable, and the loading process was rapid and efficient (drug-to-lipid ratio of up to 0.3 with over 90% efficiency in 5 minutes). The cytotoxicity of these formulations was assessed using the human melanoma cell lines A375 and Hs294T and the normal human dermal fibroblast line. The results showed that anacardic acid and to a smaller extent vitamin C significantly increased the cytotoxicity of the drug towards melanoma compared to ammonium sulfate liposomes. On the other hand, vitamin C and anacardic acid both protected normal cells from damage caused by the drug. The formulation combining anacardic acid, vitamin C, and mitoxantrone showed promising results in terms of cytotoxicity and cytoprotection. Therefore, it has potential for anticancer treatment. PMID:24489469

Salt and nitric oxide synthase inhibition-induced hypertension: kidney dysfunction and brain anti-oxidant capacity.

PubMed

Oktar, Süleyman; Ilhan, Selçuk; Meydan, Sedat; Aydin, Mehmet; Yönden, Zafer; Gökçe, Ahmet

2010-01-01

The specific aim of this study was to examine the effects of salt-loading on kidney function and brain antioxidant capacity. Wistar rats were divided into four groups: Control rats were given normal drinking water and no drug treatment for 2 weeks. LNNA group: rats were given normal drinking water and the nitric oxide (NO) inhibitor NG-nitro-L-arginine (L-NNA), 3 mg/kg/day. LNNA + Salt group: rats were given drinking water containing salt 2% and 3 mg/kg L-NNA. Salt group: rats were given drinking water containing salt 2% and no drug treatment. Basal blood pressure and the levels of serum BUN, creatinine, uric acid, cortisol, electrolyte, serum antioxidant capacity, and oxidative stress were measured. NO, superoxide dismutase (SOD), and catalase (CAT) levels were measured in the hypothalamus, brainstem, and cerebellum. Salt overload increased the blood pressure of the LNNA + Salt group. Salt-loading enhanced BUN, creatinine, sodium retention. High salt produced an increase in uric acid levels and a decrease in cortisol levels in serum. Additionally, the oxidative stress index in serum increased in the LNNA + Salt group. Salt-loading enhanced brain NO levels, but not SOD and CAT activity. L-NNA increased brain SOD activity, but not CAT and NO levels. In conclusion, salt-loading causes hypertension, kidney dysfunction, and enhances oxidative stress in salt-sensitive rats.

Long-term intake of a high-protein diet increases liver triacylglycerol deposition pathways and hepatic signs of injury in rats.

PubMed

Díaz-Rúa, Rubén; Keijer, Jaap; Palou, Andreu; van Schothorst, Evert M; Oliver, Paula

2017-08-01

Intake of high-protein (HP) diets has increased over the last years, mainly due to their popularity for body weight control. Liver is the main organ handling ingested macronutrients and it is associated with the beginning of different pathologies. We aimed to deepen our knowledge on molecular pathways affected by long-term intake of an HP diet. We performed a transcriptome analysis on liver of rats chronically fed with a casein-rich HP diet and analyzed molecular parameters related to liver injury. Chronic increase in the dietary protein/carbohydrate ratio up-regulated processes related with amino acid uptake/metabolism and lipid synthesis, promoting a molecular environment indicative of hepatic triacylglycerol (TG) deposition. Moreover, changes in expression of genes involved in acid-base maintenance and oxidative stress indicate alterations in the pH balance due to the high acid load of the diet, which has been linked to liver/health damage. Up-regulation of immune-related genes was also observed. In concordance with changes at gene expression level, we observed increased liver TG content and increased serum markers of hepatic injury/inflammation (aspartate transaminase, C-reactive protein and TNF-alpha). Moreover, the HP diet strongly increased hepatic mRNA and protein levels of HSP90, a marker of liver injury. Thus, we show for the first time that long-term consumption of an HP diet, resulting in a high acid load, results in a hepatic transcriptome signature reflecting increased TG deposition and increased signs of health risk (increased inflammation, alterations in the acid-base equilibrium and oxidative stress). Persistence of this altered metabolic status could have unhealthy consequences. Copyright © 2017 Elsevier Inc. All rights reserved.

Hyaluronic acid-modified zirconium phosphate nanoparticles for potential lung cancer therapy.

PubMed

Li, Ranwei; Liu, Tiecheng; Wang, Ke

2017-02-01

Novel tumor-targeting zirconium phosphate (ZP) nanoparticles modified with hyaluronic acid (HA) were developed (HA-ZP), with the aim of combining the drug-loading property of ZP and the tumor-targeting ability of HA to construct a tumor-targeting paclitaxel (PTX) delivery system for potential lung cancer therapy. The experimental results indicated that PTX loading into the HA-ZP nanoparticles was as high as 20.36%±4.37%, which is favorable for cancer therapy. PTX-loaded HA-ZP nanoparticles increased the accumulation of PTX in A549 lung cancer cells via HA-mediated endocytosis and exhibited superior anticancer activity in vitro. In vivo anticancer efficacy assay revealed that HA-ZP nanoparticles possessed preferable anticancer abilities, which exhibited minimized toxic side effects of PTX and strong tumor-suppression potential in clinical application.

Simultaneous determination of Ca, Cu, Ni, Zn and Cd binding strengths with fulvic acid fractions by Schubert's method

USGS Publications Warehouse

Brown, G.K.; MacCarthy, P.; Leenheer, J.A.

1999-01-01

The equilibrium binding of Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ with unfractionated Suwannee river fulvic acid (SRFA) and an enhanced metal binding subfraction of SRFA was measured using Schubert's ion-exchange method at pH 6.0 and at an ionic strength (??) of 0.1 (NaNO3). The fractionation and subfractionation were directed towards obtaining an isolate with an elevated metal binding capacity or binding strength as estimated by Cu2+ potentiometry (ISE). Fractions were obtained by stepwise eluting an XAD-8 column loaded with SRFA with water eluents of pH 1.0 to pH 12.0. Subfractions were obtained by loading the fraction eluted from XAD-8 at pH 5.0 onto a silica gel column and eluting with solvents of increasing polarity. Schuberts ion exchange method was rigorously tested by measuring simultaneously the conditional stability constants (K) of citric acid complexed with the five metals at pH 3.5 and 6.0. The logK of SRFA with Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ determined simultaneously at pH 6.0 follow the sequence of Cu2+>Cd2+>Ni2+>Zn2+>Ca2+ while all logK values increased for the enhanced metal binding subfraction and followed a different sequence of Cu2+>Cd2+>Ca2+>Ni2+>Zn2+. Both fulvic acid samples and citric acid exhibited a 1:1 metal to ligand stochiometry under the relatively low metal loading conditions used here. Quantitative 13C nuclear magnetic resonance spectroscopy showed increases in aromaticity and ketone content and decreases in aliphatic carbon for the elevated metal binding fraction while the carboxyl carbon, and elemental nitrogen, phosphorus, and sulfur content did not change. The more polar, elevated metal binding fraction did show a significant increase in molecular weight over the unfractionated SRFA. Copyright (C) 1999 Elsevier Science B.V.

Effect of cocoa pod husk filler loading on tensile properties of cocoa pod husk/polylactic acid green biocomposite films

NASA Astrophysics Data System (ADS)

Sanyang, M. L.; Sapuan, S. M.; Haron, M.

2017-10-01

Over the years, cocoa-pod husk (CPH) generation significantly increased due to the growing global demand of chocolate products, since cocoa bean is the main ingredient for chocolate production. Proper utilization of CPH as natural filler for reinforcement of polymer composites provides economic advantages as well as environmental solutions for CPH waste disposal problems. In this study, CPH filled PLA composite films were developed using solution casting method. The effect of CPH loading on the tensile properties of CPH/PLA composite films were investigated. The obtained results manifested that increasing CPH loading from 0% to 10 % significantly increased tensile strength of CPH/PLA composite. However, further addition of CPH loading up to 15 % decreased the tensile strength of film samples. As CPH loading increased from 0% to 15%, tensile modulus of CPH/PLA composite films also increased from 1.5MPa to 10.4MPa, whereas their elongation at break reduced from 190% to 90%. These findings points out CPH as a potential natural filler for reinforcing thermoplastic polymer composites.

Monfort waste conversion demonstration. Quarterly progress report, April 1, 1977--June 30, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turk, M.

1977-07-01

Progress in development of the mobile fermentation system at the Montfort cattle feedlots is reported. Fermentor startup was evaluated at operating conditions of 135/sup 0/F/57.2/sup 0/C with gradual increases in loading rates. An attempt was made to maintain the TVA (total volatile acid) concentration at a low level, but it became obvious that increases in loading rates could not be accomplished without a concomitant increase in TVA. Samples were also analyzed for heavy metals (Cu, Zn, Fe, Al) and S and P. Addition of FeCl/sub 3/ helped to reduce P, S, and TVA levels, making possible the maintenance of amore » healthy microbial colony capable of accepting increases in organic loading. (JGB)« less

Urine alkalization facilitates uric acid excretion

PubMed Central

2010-01-01

Background Increase in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We examined the possibility of facilitated excretion of uric acid by change in urine pH by managing food materials. Methods Within the framework of the Japanese government's health promotion program, we made recipes which consist of protein-rich and less vegetable-fruit food materials for H+-load (acid diet) and others composed of less protein but vegetable-fruit rich food materials (alkali diet). Healthy female students were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl-,SO42-,PO4-) necessary for the estimation of acid-base balance were measured. Results Urine pH reached a steady state 3 days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42-] +organic acid-gut alkai) were linearly related with those of the excretion of acid (titratable acidity+ [NH4+] - [HCO3-]), indicating that H+ in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, where uric acid excretion increased from 302 mg/day at pH 5.9 to 413 mg/day at pH 6.5, despite the fact that the alkali diet contained a smaller purine load than the acid diet. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed food is effective for removing uric acid from the body. PMID:20955624

Effects of ionizing radiation on sensorial, chemical, and microbiological quality of frozen corn and peas.

PubMed

Fan, Xuetong; Sokorai, Kimberly J B

2007-08-01

The effects of irradiation (0, 1.8, and 4.5 kGy) on the quality of frozen corn and peas were investigated during a 12month period of postirradiation storage at -18 degrees C. Irradiation of frozen corn and peas caused a reduction in ascorbic acid content of both vegetables and a loss of texture in peas but had no significant effects on instrumental color parameters (L*, a*, and b*), carotenoid and chlorophyll content, or antioxidant capacity of corn and peas. Irradiation reduced microbial loads of frozen peas and increased display life at 23 degrees C of thawed peas by preserving the green color, apparently because of slower increases in the population of acid-producing microorganisms in the irradiated samples. Overall, irradiation significantly reduced the microbial load and increased the display life of peas and had minimal detrimental effects on the quality of frozen corn and peas.

Optimization of Immobilized Gallium (III) Ion Affinity Chromatography for Selective Binding and Recovery of Phosphopeptides from Protein Digests

PubMed Central

Aryal, Uma K.; Olson, Douglas J.H.; Ross, Andrew R.S.

2008-01-01

Although widely used in proteomics research for the selective enrichment of phosphopeptides from protein digests, immobilized metal-ion affinity chromatography (IMAC) often suffers from low specificity and differential recovery of peptides carrying different numbers of phosphate groups. By systematically evaluating and optimizing different loading, washing, and elution conditions, we have developed an efficient and highly selective procedure for the enrichment of phosphopeptides using a commercially available gallium(III)-IMAC column (PhosphoProfile, Sigma). Phosphopeptide enrichment using the reagents supplied with the column is incomplete and biased toward the recovery and/or detection of smaller, singly phosphorylated peptides. In contrast, elution with base (0.4 M ammonium hydroxide) gives efficient and balanced recovery of both singly and multiply phosphorylated peptides, while loading peptides in a strong acidic solution (1% trifluoracetic acid) further increases selectivity toward phosphopeptides, with minimal carryover of nonphosphorylated peptides. 2,5-Dihydroxybenzoic acid, a matrix commonly used when analyzing phosphopeptides by matrix-assisted laser desorption/ionization mass spectrometry was also evaluated as an additive in loading and eluting solvents. Elution with 50% acetonitrile containing 20 mg/mL dihydroxybenzoic acid and 1% phosphoric acid gave results similar to those obtained using ammonium hydroxide as the eluent, although the latter showed the highest specificity for phosphorylated peptides. PMID:19183793

Crop load and harvest maturity effects on consumer preferences for apricots.

PubMed

Stanley, Jill; Feng, Jinquan; Olsson, Shane

2015-03-15

Improving apricot fruit quality delivered to consumers is key to ensuring a successful apricot industry. Previous studies have focused on effects of either soluble solids content (SSC) or fruit firmness on consumer preferences, and results have been equivocal. This study evaluated the effects of crop load and harvest maturity how they affected on fruit SSC and firmness, and on subsequent consumer preferences. SSC of apricots was an important factor only when fruit were firmer than 15 N and not immature. When fruit were softer than 15 N, SSC had little influence on consumer liking. In general, consumers preferred fruit that were grown on trees thinned to approximately 10-20% less than typical commercial crop loads and were harvested in a more mature condition. Consumers also preferred fruit that had a higher sugar/acid ratio or BrimA value, which is the °Brix - k × titratable acidity, where k is a constant that varies between species and cultivars depending on the specific acids and sugars present. High apricot flavour and juiciness were associated with greater sweetness. Management practices that increase fruit SSC and sugar/acid ratio, such as reducing crop load, will improve consumer satisfaction as long as fruit are harvested at an adequate maturity stage and are maintained in storage so that they do not soften too quickly. © 2014 Society of Chemical Industry.

Effects of Lewis acidity of metal oxide promoters on the activity and selectivity of Co-based Fischer–Tropsch synthesis catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Gregory R.; Bell, Alexis T.

2016-06-17

Metal oxides of Ce, Gd, La, Mn, and Zr were investigated as promoters for improving the activity and selectivity of Co-based FTS catalysts. The extent to which these promoters decrease the selectivity toward CH 4 and increase the selectivity toward C 5+ hydrocarbons was found to depend on both the loading and the composition of the oxide promoter. Elemental mapping by STEM–EDS revealed that the propensity for a given metal oxide to associate with Co affects the sensitivity of the product distribution to changes in promoter loading. For all promoters, a sufficiently high loading resulted in the product distributions becomingmore » insensitive to further increases in promoter loading, very likely due to the formation of a half monolayer of promoter oxide over the Co surface. Simulations suggest that the fraction of Co active sites that are adjacent to the promoter moieties approaches unity at this degree of coverage. The oxidation state of the promoter metal cation under reaction conditions, determined by in situ XANES measurements, was used to calculate relative Lewis acidity of the promoter metal cation. A strong positive correlation was found between the C 5+ product selectivity and the Lewis acidity of the promoter metal cations, suggesting that the promotional effects are a consequence of Lewis acid–base interactions between the reaction intermediates and the promoter metal cations. Rate data obtained at different pressures were used to estimate the apparent rate coefficient and the CO adsorption constant appearing in the Langmuir–Hinshelwood expression that describes the CO consumption kinetics for both unpromoted and the metal oxide-promoted catalysts. Both parameters exhibited positive correlations with the promoter Lewis acidity. In conclusion, these results are consistent with the hypothesis that the metal cations of the promoter act as Lewis acids that interact with the O atom of adsorbed CO to facilitate CO adsorption and dissociation.« less

Biochemical Characterization of β-Amino Acid Incorporation in Fluvirucin B 2 Biosynthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barajas, Jesus F.; Zargar, Amin; Pang, Bo

Naturally occurring lactams, such as the polyketide-derived macrolactams, provide a diverse class of natural products that could enhance existing chemically produced lactams. While β-amino acid loading in the fluvirucin B 2 polyketide pathway has been proposed by a previously identified putative biosynthetic gene cluster, biochemical characterization of the complete loading enzymes has not been described. In this paper, we elucidate the complete biosynthetic pathway of the β-amino acid loading pathway in fluvirucin B 2 biosynthesis. We demonstrate the promiscuity of the loading pathway to utilize a range of amino acids and further illustrate the ability to introduce non-native acyl transferasesmore » to selectively transfer β-amino acids onto a PKS loading platform. The results presented here provide a detailed biochemical description of β-amino acid selection and will further aid in future efforts to develop engineered lactam-producing PKS platforms.« less

Biochemical Characterization of β-Amino Acid Incorporation in Fluvirucin B 2 Biosynthesis

DOE PAGES

Barajas, Jesus F.; Zargar, Amin; Pang, Bo; ...

2018-03-30

Naturally occurring lactams, such as the polyketide-derived macrolactams, provide a diverse class of natural products that could enhance existing chemically produced lactams. While β-amino acid loading in the fluvirucin B 2 polyketide pathway has been proposed by a previously identified putative biosynthetic gene cluster, biochemical characterization of the complete loading enzymes has not been described. In this paper, we elucidate the complete biosynthetic pathway of the β-amino acid loading pathway in fluvirucin B 2 biosynthesis. We demonstrate the promiscuity of the loading pathway to utilize a range of amino acids and further illustrate the ability to introduce non-native acyl transferasesmore » to selectively transfer β-amino acids onto a PKS loading platform. The results presented here provide a detailed biochemical description of β-amino acid selection and will further aid in future efforts to develop engineered lactam-producing PKS platforms.« less

Calcium, Magnesium, and Phosphorus Metabolism, and Parathyroid- Calcitonin Function during Prolonged Exposure to Elevated CO2 Concentrations on Submarines

DTIC Science & Technology

1975-12-01

renal regulation, determine acid- base balance. calcitonin activity calcium excretion chronic hypercapnia magnesium parathyroid phosphorus...Mg increased. An important aspect of acid- base and electrolyte balance is the renal handling of an acid load. Figure 2 presents data on urine...E. SCHAEFER Navat Submarine Medical Research Laboratory, Naval Submarine Base , Groton, CT 06340 Messier, A. A., E. Heyder, W. R. Braithwaite, C

Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches.

PubMed

Madureira, Ana Raquel; Nunes, Sara; Campos, Débora A; Fernandes, João C; Marques, Cláudia; Zuzarte, Monica; Gullón, Beatriz; Rodríguez-Alcalá, Luís M; Calhau, Conceição; Sarmento, Bruno; Gomes, Ana Maria; Pintado, Maria Manuela; Reis, Flávio

2016-01-01

Rosmarinic acid (RA) possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe) delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL) were evaluated for cell (lymphocytes) viability, necrosis and apoptosis, and antioxidant/prooxidant effects upon DNA. Wistar rats were orally treated for 14 days with vehicle (control) and with Witepsol or Carnauba nanoparticles loaded with RA at 1 and 10 mg/kg body weight/d. Blood, urine, feces, and several tissues were collected for analysis. Free and loaded RA, at 0.15 mg/mL, presented a safe profile, while genotoxic potential was found for the higher dose (1.5 mg/mL), mainly by necrosis. Our data suggest that both types of nanoparticles are safe when loaded with moderate concentrations of RA, without in vitro genotoxicity and cytotoxicity and with an in vivo safety profile in rats orally treated, thus opening new avenues for use in nutraceutical applications.

Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches

PubMed Central

Madureira, Ana Raquel; Nunes, Sara; Campos, Débora A; Fernandes, João C; Marques, Cláudia; Zuzarte, Monica; Gullón, Beatriz; Rodríguez-Alcalá, Luís M; Calhau, Conceição; Sarmento, Bruno; Gomes, Ana Maria; Pintado, Maria Manuela; Reis, Flávio

2016-01-01

Rosmarinic acid (RA) possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe) delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL) were evaluated for cell (lymphocytes) viability, necrosis and apoptosis, and antioxidant/prooxidant effects upon DNA. Wistar rats were orally treated for 14 days with vehicle (control) and with Witepsol or Carnauba nanoparticles loaded with RA at 1 and 10 mg/kg body weight/d. Blood, urine, feces, and several tissues were collected for analysis. Free and loaded RA, at 0.15 mg/mL, presented a safe profile, while genotoxic potential was found for the higher dose (1.5 mg/mL), mainly by necrosis. Our data suggest that both types of nanoparticles are safe when loaded with moderate concentrations of RA, without in vitro genotoxicity and cytotoxicity and with an in vivo safety profile in rats orally treated, thus opening new avenues for use in nutraceutical applications. PMID:27536103

Amino acid supplementation alters bone metabolism during simulated weightlessness

NASA Technical Reports Server (NTRS)

Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

2005-01-01

High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

The effect of loading carbon nanotubes onto chitosan films on electrochemical dopamine sensing in the presence of biological interference.

PubMed

Shukla, Sudheesh K; Lavon, Avia; Shmulevich, Offir; Ben-Yoav, Hadar

2018-05-01

In vivo monitoring of the neurotransmitter dopamine can potentially improve the diagnosis of neurological disorders and elucidate their underlying biochemical mechanisms. While electrochemical sensors can detect unlabeled dopamine molecules, their sensing performance is dramatically reduced by electrochemical currents generated by other, interfering molecules (e.g., uric acid) in the biological environment. To overcome this caveat, the surface of the sensor is often modified with electrocatalytic materials, which are encapsulated inside a polymeric film; however, the effect of the encapsulating film on the sensing performance of the electrode has not been systematically studied. This study characterizes the effect of loading carbon nanotubes (CNTs) onto a chitosan film on the electrochemical sensing performance of dopamine in the presence of uric acid. Higher CNT loading increases the diffusion and electron transfer rate coefficients of the sensor and, in the presence of uric acid, provides better sensitivity (3.00µALµmol -1 for 1.75% CNT loading, vs 0.01µALµmol -1 for 1% loading) but a poorer limit-of-detection (2.00µmolL -1 vs 1.00, respectively), as reported here for the first time. These findings can help optimize the sensitivity and the limit-of-detection of electrochemical sensors in complex biofluids to enable an in vivo monitoring of dopamine and other redox-active molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

Insulin-loaded pH-sensitive hyaluronic acid nanoparticles enhance transcellular delivery.

PubMed

Han, Lina; Zhao, Yuefang; Yin, Lifang; Li, Ruiming; Liang, Yang; Huang, Huan; Pan, Shirong; Wu, Chuanbin; Feng, Min

2012-09-01

In the present study, we developed novel insulin-loaded hyaluronic acid (HA) nanoparticles for insulin delivery. The insulin-loaded HA nanoparticles were prepared by reverse-emulsion-freeze-drying method. This method led to a homogenous population of small HA nanoparticles with average size of 182.2 nm and achieved high insulin entrapment efficiencies (approximately 95%). The pH-sensitive HA nanoparticles as an oral delivery carrier showed advantages in protecting insulin against the strongly acidic environment of the stomach, and not destroying the junction integrity of epithelial cells which promise long-term safety for chronic insulin treatment. The results of transport experiments suggested that insulin-loaded HA nanoparticles were transported across Caco-2 cell monolayers mainly via transcellular pathway and their apparent permeability coefficient from apical to basolateral had more than twofold increase compared with insulin solution. The efflux ratio of P (app) (B to A) to P (app) (A to B) less than 1 demonstrated that HA nanoparticle-mediated transport of insulin across Caco-2 cell monolayers underwent active transport. The results of permeability through the rat small intestine confirmed that HA nanoparticles significantly enhanced insulin transport through the duodenum and ileum. Diabetic rats treated with oral insulin-loaded HA nanoparticles also showed stronger hypoglycemic effects than insulin solution. Therefore, these HA nanoparticles could be a promising candidate for oral insulin delivery.

Liver-targeting self-assembled hyaluronic acid-glycyrrhetinic acid micelles enhance hepato-protective effect of silybin after oral administration.

PubMed

Han, Xiaofeng; Wang, Zhe; Wang, Manyuan; Li, Jing; Xu, Yongsong; He, Rui; Guan, Hongyu; Yue, Zhujun; Gong, Muxin

2016-06-01

In order to enhance oral bioavailability and liver targeting delivery of silybin, two amphiphilic hyaluronic acid derivatives, hyaluronic acid-deoxycholic acid (HA-adh-DOCA) and hyaluronic acid-glycyrrhetinic acid (HA-adh-GA) conjugates, were designed and synthesized. Silybin was successfully loaded in HA-adh-DOCA and HA-adh-GA micelles with high drug-loading capacities (20.3% ± 0.5% and 20.6% ± 0.6%, respectively). The silybin-loaded micelles were spherical in shape with the average size around 130 nm. In vitro release study showed that two silybin-loaded micelles displayed similar steady continued-release pattern in simulated gastrointestinal fluids and PBS. Single-pass intestinal perfusion studies indicated that silybin-loaded micelles were absorbed in the whole intestine and transported via a passive diffusion mechanism. Compared with suspension formulation, silybin-loaded HA-adh-DOCA and HA-adh-GA micelles achieved significantly higher AUC and Cmax level. Moreover, liver targeting drug delivery of micelles was confirmed by in vivo imaging analysis. In comparison between the two micellar formulations, HA-adh-GA micelles possessed higher targeting capacity than HA-adh-DOCA micelles, owing to the active hepatic targeting properties of glycyrrhetinic acid. In the treatment of acute liver injury induced by CCl4, silybin-loaded HA-adh-GA micelles displayed better effects over suspension control and silybin-loaded HA-adh-DOCA micelles. Overall, pharmaceutical and pharmacological indicators suggested that the HA-adh-GA conjugates can be successfully utilized for liver targeting of orally administered therapeutics.

Assessing relationships between red spruce radial growth and pollution critical load exceedance values

Treesearch

Benjamin J. Engel; Paul G. Schaberg; Gary J. Hawley; Shelly A. Rayback; Jennifer Pontius; Alexandra M. Kosiba; Eric K. Miller

2016-01-01

Acidic sulfur (S) and nitrogen (N) deposition depletes cations such as calcium (Ca) from forest soils and has been linked to increases in foliar winter injury that led to the decline of red spruce (Picea rubens Sarg.) in the northeastern United States. We used results from a 30 m resolution steady-state S and N critical load exceedance model for New...

The Effect of Buffering High Acid Load Meal with Sodium Bicarbonate on Postprandial Glucose Metabolism in Humans-A Randomized Placebo-Controlled Study.

PubMed

Kozan, Pinar; Blythe, Jackson C; Greenfield, Jerry R; Samocha-Bonet, Dorit

2017-08-11

Background: High dietary acid load relates to increased risk of type 2 diabetes in epidemiological studies. We aimed to investigate whether buffering a high acid load meal with an alkalizing treatment changes glucose metabolism post meal. Methods: Non-diabetic participants ( n = 32) were randomized to receive either 1680 mg NaHCO₃ or placebo, followed by a high acid load meal in a double-blind placebo-controlled crossover (1-4 weeks apart) study. Thirty (20 men) participants completed the study. Venous blood pH, serum bicarbonate, blood glucose, serum insulin, C -peptide, non-esterified fatty acid (NEFA), and plasma glucagon-like peptide-1 (GLP-1) concentrations were measured at baseline (fasting) and at 15-30 min intervals for 3 h post meal. Results: The treatment was well tolerated. Venous blood pH declined in the first 15 min post meal with the placebo ( p = 0.001), but not with NaHCO₃ ( p = 0.86) and remained decreased with the placebo for 3 h ( p interaction = 0.04). On average over the 3 h blood pH iAUC was greater with NaHCO₃ compared with placebo ( p = 0.02). However, postprandial glucose, insulin, C -peptide, NEFA and GLP-1 were not different between treatments ( p interaction ≥ 0.07). Conclusions: An alkalizing medication administered pre-meal has no acute effect on glycaemia and insulin response in healthy individuals. Long-term interventions in at-risk populations are necessary to investigate the effect of sustained alkalization on glucose metabolism.

Boric acid-enhanced embedding medium for cryomicrotomy.

PubMed

Lim, Jin Ik; Park, Hun-Kuk

2012-05-01

A polyvinyl alcohol (PVA)/polyethylene glycol (PEG)-based resin is commonly used as a cryoembedding medium for the histological analysis of frozen tissue sections. However, it is not easy to obtain sufficient numbers of satisfactory reproducible sections owing to the differences between the mechanical properties of the medium and embedded tissue and the low cohesive force of the medium. We describe a modified PVA-based cryoembedding medium, composed of PVA (10wt% and 15wt%) with the addition of boric acid (from 0 to 5wt%), that can improve the sectioning properties and efficiency of frozen tissue for histological analysis. The amount of load under the same compressive displacement as well as cohesive force increased with increasing boric acid and PVA contents. 15wt% PVA and 3wt% boric acid was determined as an optimal composition for cryoembedding material based on the sectioning efficiency measured by the numbers of unimpaired sectioned slices and the amount of load under the same compressive displacement test. On the basis of the results of routine hematoxylin and eosin staining of cryosections of tissue embedded in a medium with 3wt% boric acid and PVA, it was concluded that the modified PVA cryoembedding medium can improve the efficiency of cryosectioning for subsequent histological or histochemical analysis of various tissues. Copyright © 2011 Elsevier GmbH. All rights reserved.

Tribological Behavior of Electroless Ni-P Coatings in Various Corrosive Environments

NASA Astrophysics Data System (ADS)

Panja, Bikash; Das, Suman Kalyan; Sahoo, Prasanta

2016-04-01

The present paper deals with the study of tribological characteristics, viz. friction and wear, of electroless Ni-P coating in corrosive environments (brine, acidic and alkaline) by varying different coating process parameters as well as varying the tribological testing parameters, viz. applied load and speed. The optimized results of coating process parameters for minimum friction and wear performance of the coating are presented. Moreover, a detailed study of the tribological behavior of the coating is undertaken individually for the three corrosive environments. The results obtained are compared among each other and also with the dry condition test of the coating. It is found that the friction coefficient of Ni-P coating decreases with increase in load for all environments. In case of wear, the wear rate of Ni-P coating gradually increases with increase in load for all mediums but the same decreases after 40N in brine and alkaline mediums. However, for acidic solution, the wear rate shows a continuous increasing trend. It is observed that alkaline and brine environments are favorable from friction and wear point of view of the coating, respectively. Microstructure study of the coatings is also performed and the coating is found to be of cauliflower-like morphology. The coating also exhibits amorphous structure in as-deposited condition, which gradually turns crystalline with heat treatment.

Effect of expanded organoclay by stearic acid to curing, mechanical and swelling properties of natural rubber nanocomposites

NASA Astrophysics Data System (ADS)

Ramadhan, A.; Fathurrohman, M. Irfan; Falaah, A. F.; Setyawan, N.; Soegijono, B.

2017-07-01

The interlayer basal spacing of organoclay (OC) could be increased with stearic acid (SA) added, thus OC changed into expanded organoclay by SA (OCSA). The effect of various loadings of OCSA on the curing, mechanical and swelling properties of natural rubber (NR) nanocomposites were studied. The natural rubber/expanded organoclay (NR/OCSA) nanocomposites were prepared by melt intercalation using a laboratory open mill. The curing characteristics of NR compounds were determined using a Moving Die Rheometer (MDR). The X-ray Diffraction (XRD), Attenuated Total Reflectance Infrared (ATR-IR) Spectroscopy and Field Emission Scanning Electron Microscopy (FESEM) were used to study the dispersion of OCSA in the NR matrix. The mechanical properties of NR/OCSA nanocomposites such as tensile strength, elongation at break and hardness were determined using ISO standard and swelling of NR/OCSA nanocomposites in toluene were determined using ISO 1817. The results showed that the SA intercalated into the gallery of OC and reacted with the hydroxyl groups in OC. It was indicated with the shifting of the negative peak 1,700 to 1,723 cm-1 in the ATR-IR spectrum and increase the d-spacing of OC. The adding of various loadings of OCSA into NR could increase the torque and accelerate the curing of nanocomposites and it also could increase the mechanical and swelling properties of nanocomposites. The change in modulus at 100% elongation significantly increased with increasing the OCSA load until maximum loading at 10 phr. This trend was same with the hardness and modulus at 300% elongation. Meanwhile, the improvement of tensile strength and elongation at break was higher at 4 phr OCSA compared with the other loading. The increase of mechanical and swelling properties of NR/OCSA nanocomposites was due to intercalation/exfoliation of OCSA in NR matrix. It was revealed by appearing of the out-of-plane Si-O-(Al) stretch with peak value 1080 cm-1 in the ATR-IR spectrum and the peaks of OCSA in the XRD pattern was disappeared until the loading of OCSA 8 phr and the thickness of morphology of OCSA below 100 nm.

Caffeic acid production by simultaneous saccharification and fermentation of kraft pulp using recombinant Escherichia coli.

PubMed

Kawaguchi, Hideo; Katsuyama, Yohei; Danyao, Du; Kahar, Prihardi; Nakamura-Tsuruta, Sachiko; Teramura, Hiroshi; Wakai, Keiko; Yoshihara, Kumiko; Minami, Hiromichi; Ogino, Chiaki; Ohnishi, Yasuo; Kondo, Ahikiko

2017-07-01

Caffeic acid (3,4-dihydroxycinnamic acid) serves as a building block for thermoplastics and a precursor for biologically active compounds and was recently produced from glucose by microbial fermentation. To produce caffeic acid from inedible cellulose, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactions were compared using kraft pulp as lignocellulosic feedstock. Here, a tyrosine-overproducing Escherichia coli strain was metabolically engineered to produce caffeic acid from glucose by introducing the genes encoding a 4-hydroxyphenyllactate 3-hydroxylase (hpaBC) from Pseudomonas aeruginosa and tyrosine ammonia lyase (fevV) from Streptomyces sp. WK-5344. Using the resulting recombinant strain, the maximum yield of caffeic acid in SSF (233 mg/L) far exceeded that by SHF (37.9 mg/L). In the SSF with low cellulase loads (≤2.5 filter paper unit/g glucan), caffeic acid production was markedly increased, while almost no glucose accumulation was detected, indicating that the E. coli cells experienced glucose limitation in this culture condition. Caffeic acid yield was also negatively correlated with the glucose concentration in the fermentation medium. In SHF, the formation of by-product acetate and the accumulation of potential fermentation inhibitors increased significantly with kraft pulp hydrolysate than filter paper hydrolysate. The combination of these inhibitors had synergistic effects on caffeic acid fermentation at low concentrations. With lower loads of cellulase in SSF, less potential fermentation inhibitors (furfural, 5-hydroxymethyfurfural, and 4-hydroxylbenzoic acid) accumulated in the medium. These observations suggest that glucose limitation in SSF is crucial for improving caffeic acid yield, owing to reduced by-product formation and fermentation inhibitor accumulation.

Alkaline Diet and Metabolic Acidosis: Practical Approaches to the Nutritional Management of Chronic Kidney Disease.

PubMed

Rodrigues Neto Angéloco, Larissa; Arces de Souza, Gabriela Cristina; Almeida Romão, Elen; Garcia Chiarello, Paula

2018-05-01

The kidneys play an extremely important role in maintaining the body acid-base balance by excreting nonvolatile acids and regenerating and reabsorbing bicarbonate in the kidney tubules. As the individual loses their kidney function, renal excretion of nonvolatile acid produced by metabolism of the diet is impaired, resulting in low-grade metabolic acidosis. With this in mind, it is relevant to better understand the dietary aspects related to the acid-base balance in chronic kidney disease metabolic acidosis and try to provide possible strategies for the nutritional management of these cases. The type of diet can deeply affect the body by providing acid or base precursors. Generally speaking, foods such as meat, eggs, cheese, and grains increase the production of acid in the organism, whereas fruit and vegetables are alkalizing. On the other hand, milk is considered neutral as well as fats and sugars, which have a small effect on acid-base balance. The modern Western-type diet is deficient in fruits and vegetables and contains excessive animal products. Thus metabolic acidosis may be exacerbated by a contemporary Western diet, which delivers a high nonvolatile acid load. The remaining acid is neutralized or stored within the body. Bone and muscle are lost to neutralize the acid and serum bicarbonate falls. Early studies suggest that lowering the dietary acid load with a reduced protein content and vegetable proteins replacements, associated with an increase in fruits and vegetables intake can improve the metabolic parameters of acidosis, preserve bone and muscle, and slow the glomerular filtration rate decline. More studies focusing on the effects of controlled dietary interventions among chronic kidney disease patients are needed to determining the optimal target for nutritional therapy. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Influence of Fe loadings on desulfurization performance of activated carbon treated by nitric acid.

PubMed

Guo, Jia-Xiu; Shu, Song; Liu, Xiao-Li; Wang, Xue-Jiao; Yin, Hua-Qiang; Chu, Ying-Hao

2017-02-01

A series of Fe supported on activated carbon treated by nitric acid are prepared by incipient wetness impregnation with ultrasonic assistance and characterized by N 2 adsorption-desorption, X-ray diffraction, Fourier transform infrared spectrum and X-ray photoelectron spectroscopy. It has shown that Fe loadings significantly influence the desulfurization activity. Fe/NAC5 exhibits an excellent removal ability of SO 2 , corresponding to breakthrough sulfur capacity of 323 mg/g. With the increasing Fe loadings, the generated Fe 3 O 4 and Fe 2 SiO 4 increase, but Fe 2 (SO 4 ) 3 is observed after desulfurization. Fe/NAC1 has a Brunauer-Emmett-Teller (BET) surface area of 925 m 2 /g with micropore surface area of 843 m 2 /g and total pore volume of 0.562 cm 3 /g including a micropore volume of 0.300 cm 3 /g. With the increasing Fe loadings, BET surface area and micropore volume decrease, and those of Fe/NAC10 decrease to 706 m 2 /g and 0.249 cm 3 /g. The Fe loadings influence the pore-size distribution, and SO 2 adsorption mainly reacts in micropores at about 0.70 nm. C=O and C-O are observed for all samples before SO 2 removal. After desulfurization, the C-O stretching is still detected, but the C=O stretching vibration of carbonyl groups disappears. The stretching of S-O or S=O in sulfate is observed at 592 cm -1 for the used sample, proving that the existence of [Formula: see text].

The effects of biodegradable poly(lactic-co-glycolic acid)-based microspheres loaded with quercetin on stemness, viability and osteogenic differentiation potential of stem cell spheroids.

PubMed

Lee, H; Nguyen, T T; Kim, M; Jeong, J-H; Park, J-B

2018-05-31

Quercetin has been reported to exert many beneficial effects on the protection against various diseases, such as diabetes, cancer, and inflammation. The aim of this study is to evaluate the potential osteogenic differentiation ability of mesenchymal stem cells in the presence of quercetin. Quercetin-loaded poly(lactic-co-glycolic acid) microspheres were prepared using an electrospraying technique. Characterization of the microspheres was evaluated with a scanning electron microscope and release profile. Three-dimensional cell spheroids were fabricated using silicon elastomer-based concave microwells. Qualitative results of cellular viability were seen under a confocal microscope, and quantitative cellular viability was evaluated using the Cell Counting Kit-8 assay. The alkaline phosphatase activity and Alizarin Red S staining were performed. A quantitative real-time polymerase chain reaction and a western blot analysis were performed. Spheroids were well formed irrespective of quercetin concentration. Most of the cells in spheroids emitted green fluorescence, and the morphology was round without significant changes. The application of quercetin-loaded microspheres produced a significant increase in the alkaline phosphatase activity. The real-time polymerase chain reaction results showed a significant increase in Runx2, and western blot results showed higher expression of Runx2 protein expression. Biodegradable microspheres loaded with quercetin produced prolonged release profiles with increased mineralization. Microspheres loaded with quercetin can be used for the enhancement of osteoblastic differentiation in cell therapy. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Autophagic clearance of mitochondria in the kidney copes with metabolic acidosis.

PubMed

Namba, Tomoko; Takabatake, Yoshitsugu; Kimura, Tomonori; Takahashi, Atsushi; Yamamoto, Takeshi; Matsuda, Jun; Kitamura, Harumi; Niimura, Fumio; Matsusaka, Taiji; Iwatani, Hirotsugu; Matsui, Isao; Kaimori, Junya; Kioka, Hidetaka; Isaka, Yoshitaka; Rakugi, Hiromi

2014-10-01

Metabolic acidosis, a common complication of CKD, causes mitochondrial stress by undefined mechanisms. Selective autophagy of impaired mitochondria, called mitophagy, contributes toward maintaining cellular homeostasis in various settings. We hypothesized that mitophagy is involved in proximal tubular cell adaptations to chronic metabolic acidosis. In transgenic mice expressing green fluorescent protein-tagged microtubule-associated protein 1 light chain 3 (GFP-LC3), NH4Cl loading increased the number of GFP puncta exclusively in the proximal tubule. In vitro, culture in acidic medium produced similar results in proximal tubular cell lines stably expressing GFP-LC3 and facilitated the degradation of SQSTM1/p62 in wild-type cells, indicating enhanced autophagic flux. Upon acid loading, proximal tubule-specific autophagy-deficient (Atg5-deficient) mice displayed significantly reduced ammonium production and severe metabolic acidosis compared with wild-type mice. In vitro and in vivo, acid loading caused Atg5-deficient proximal tubular cells to exhibit reduced mitochondrial respiratory chain activity, reduced mitochondrial membrane potential, and fragmented morphology with marked swelling in mitochondria. GFP-LC3-tagged autophagosomes colocalized with ubiquitinated mitochondria in proximal tubular cells cultured in acidic medium, suggesting that metabolic acidosis induces mitophagy. Furthermore, restoration of Atg5-intact nuclei in Atg5-deficient proximal tubular cells increased mitochondrial membrane potential and ammoniagenesis. In conclusion, metabolic acidosis induces autophagy in proximal tubular cells, which is indispensable for maintaining proper mitochondrial functions including ammoniagenesis, and thus for adapted urinary acid excretion. Our results provide a rationale for the beneficial effect of alkali supplementation in CKD, a condition in which autophagy may be reduced, and suggest a new therapeutic option for acidosis by modulating autophagy. Copyright © 2014 by the American Society of Nephrology.

Effects of microbial loading and sporulation temperature on atmospheric plasma inactivation of Bacillus subtilis spores

NASA Astrophysics Data System (ADS)

Deng, X. T.; Shi, J. J.; Shama, G.; Kong, M. G.

2005-10-01

Current inactivation studies of Bacillus subtilis spores using atmospheric-pressure glow discharges (APGD) do not consider two important factors, namely microbial loading at the surface of a substrate and sporulation temperature. Yet these are known to affect significantly microbial resistance to heat and hydrogen peroxide. This letter investigates effects of microbial loading and sporulation temperature on spore resistance to APGD. It is shown that microbial loading can lead to a stacking structure as a protective shield against APGD treatment and that high sporulation temperature increases spore resistance by altering core water content and cross-linked muramic acid content of B. subtilis spores.

Efficient pH Dependent Drug Delivery to Target Cancer Cells by Gold Nanoparticles Capped with Carboxymethyl Chitosan

PubMed Central

Madhusudhan, Alle; Reddy, Gangapuram Bhagavanth; Venkatesham, Maragoni; Veerabhadram, Guttena; Kumar, Dudde Anil; Natarajan, Sumathi; Yang, Ming-Yeh; Hu, Anren; Singh, Surya S.

2014-01-01

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer. PMID:24821542

Usnic acid-loaded biocompatible magnetic PLGA-PVA microsphere thin films fabricated by MAPLE with increased resistance to staphylococcal colonization.

PubMed

Grumezescu, V; Holban, A M; Grumezescu, A M; Socol, G; Ficai, A; Vasile, B S; Truscă, R; Bleotu, C; Lazar, V; Chifiriuc, C M; Mogosanu, G D

2014-09-01

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering.

Production of d-lactic acid from hardwood pulp by mechanical milling followed by simultaneous saccharification and fermentation using metabolically engineered Lactobacillus plantarum.

PubMed

Hama, Shinji; Mizuno, Shino; Kihara, Maki; Tanaka, Tsutomu; Ogino, Chiaki; Noda, Hideo; Kondo, Akihiko

2015-01-01

This study focused on the process development for the d-lactic acid production from cellulosic feedstocks using the Lactobacillus plantarum mutant, genetically modified to produce optically pure d-lactic acid from both glucose and xylose. The simultaneous saccharification and fermentation (SSF) using delignified hardwood pulp (5-15% loads) resulted in the lactic acid titers of 55.2-84.6g/L after 72h and increased productivities of 1.77-2.61g/L/h. To facilitate the enzymatic saccharification of high-load pulp at a fermentation temperature, short-term (⩽10min) pulverization of pulp was conducted, leading to a significantly improved saccharification with the suppressed formation of formic acid by-product. The short-term milling followed by SSF resulted in a lactic acid titer of 102.3g/L, an optical purity of 99.2%, and a yield of 0.879g/g-sugars without fed-batch process control. Therefore, the process presented here shows promise for the production of high-titer d-lactic acid using the L. plantarum mutant. Copyright © 2015 Elsevier Ltd. All rights reserved.

Amide and Ester-Functionalized Humic Acid for Fuel Combustion Enhancement

NASA Astrophysics Data System (ADS)

Riggs, Mark

Humic acid is a class of naturally occurring molecules composed of large sheet-like regions of cyclic aromatic hydrocarbon networks with surface and edge functional groups including phenols, carboxylic acids, and epoxides. These naturally occurring molecules are found in brown coal deposits near lignite formations. Humic acid has gained attention from the scientific community as a precursor for graphene. Graphene is a 2-dimensional honeycomb structure of fully unsaturated carbon atoms that has exceptional material properties and inherent aromaticity. Graphene's incredible properties are matched by the difficulty associated with reproducibly manufacturing it on a large scale. This issue has limited the use of graphene for commercial applications. The polar functional groups of humic acid contribute to the hydrophilic nature of the molecule, limiting its miscibility in any alkyl-based solvent. Surfactants containing long alkyl chains can affect the miscibility of the molecule in an organic solvent. Surfactants are often difficult to remove from the system. It is theorized that alkylation of the functional sites of humic acid can affect the hydrophilic nature of the molecule, and effectively enable its dispersion into organic solvents without simultaneous incorporation of surfactants. This dissertation investigated the amidation and esterification of humic acid molecules extracted from leonardite. The resulting change in the modified humic acid dispersibility in organic solvents and its potential usage as a fuel additive were evaluated. Butyl, hexyl, octyl, and decyl amide-modified and ester-modified humic acids were synthesized. These products were characterized to confirm successful chemical reaction through thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The decyl-modified humic acids remained suspended in kerosene mixtures for longer than 1 week. Other organo-humic acids showed varying degrees of flocculation. The modified humic acid samples were diluted with kerosene to identify the influence on combustion properties. Butyl-modified humic acid samples decreased the molar enthalpy of combustion. Hexyl, octyl, and decyl-modified humic acids improved the combustion values. Decyl amide-modified humic acid showed the largest improvement of these mixtures with a 0.9% increase from the expected molar enthalpy of combustion with a loading percentage of 0.36% in kerosene. Octyl amide-modified and octyl ester-modified humic acid mixtures were prepared in 0.05, 0.1, and 1% loading percentage dilutions to study the effect of modified humic acid loading percent on combustion properties. The 0.1% dilution showed the largest increase of the expected molar enthalpy of combustion by 1.14% and 0.4% for amide-modified HA and ester-modified HA, respectively.

Friction and wear of iron in sulfuric acid

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1983-01-01

Elemental iron sliding on aluminum oxide in aerated sulfuric acid concentrations ranging from very dilute (0.000007 N; i.e., 4 ppm) to very concentrated (96 percent acid) was studied. Load and reciprocating sliding speeds were kept constant. With the most dilute acid of 0.7 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent, the high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid, and decreased somewhat at 50 percent in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It is apparent that the normal passivating film was being worn away and a galvanic cell established which rapidly attached to the wear area.

Characterization and anticancer potential of ferulic acid-loaded chitosan nanoparticles against ME-180 human cervical cancer cell lines

NASA Astrophysics Data System (ADS)

Panwar, Richa; Sharma, Asvene K.; Kaloti, Mandeep; Dutt, Dharm; Pruthi, Vikas

2016-08-01

Ferulic acid (FA) is a widely distributed hydroxycinnamic acid found in various cereals and fruits exhibiting potent antioxidant and anticancer activities. However, due to low solubility and permeability, its availability to biological systems is limited. Non-toxic chitosan-tripolyphosphate pentasodium (CS-TPP) nanoparticles (NPs) are used to load sparingly soluble molecules and drugs, increasing their bioavailability. In the present work, we have encapsulated FA into the CS-TPP NPs to increase its potential as a therapeutic agent. Different concentrations of FA were tested to obtain optimum sized FA-loaded CS-TPP nanoparticles (FA/CS-TPP NPs) by ionic gelation method. Nanoparticles were characterized by scanning electron microscopy, Fourier transformation infrared spectroscopy (FTIR), thermogravimetric analyses and evaluated for their anticancer activity against ME-180 human cervical cancer cell lines. The FTIR spectra confirmed the encapsulation of FA and thermal analysis depicted its degradation profile. A concentration-dependent relationship between FA encapsulation efficiency and FA/CS-TPP NPs diameter was observed. Smooth and spherical FA-loaded cytocompatible nanoparticles with an average diameter of 125 nm were obtained at 40 µM FA conc. The cytotoxicity of 40 µM FA/CS-TPP NPs against ME-180 cervical cancer cell lines was found to be higher as compared to 40 µM native FA. Apoptotic morphological changes as cytoplasmic remnants and damaged wrinkled cells in ME-180 cells were visualized using scanning electron microscopic and fluorescent microscopic techniques. Data concluded that chitosan enveloped FA nanoparticles could be exploited as an excellent therapeutic drug against cancer cells proliferation.

A modified approach for estimating the aquatic critical load of acid deposition in northern Saskatchewan, Canada

NASA Astrophysics Data System (ADS)

Whitfield, Colin J.; Mowat, Aidan C.; Scott, Kenneth A.; Watmough, Shaun A.

2016-12-01

Acid-sensitive ecosystems are found in northern Saskatchewan, which lies downwind of major sulphur (S) and nitrogen (N) emissions sources associated with the oil sands extraction industry. In order to protect these ecosystems against acidification, tolerance to acid deposition must be quantified. The suitability of the central empirical relationship used in the Steady-State Water Chemistry (SSWC) model to predict historical sulphate (SO4) concentrations was investigated, and an alternate approach for determining aquatic critical loads of acidity (CL(A)) was employed for the study lakes (n = 260). Critical loads of acidity were often low, with median values of 12-16 mmolc m-2 yr-1, with the lower value reflecting a region-specific limit for acid-neutralizing capacity identified in this study. Uncertain levels of atmospheric deposition in the region, however, are problematic for characterizing acidification risk. Accurate S and chloride (Cl) deposition are needed to identify catchment sources (and sinks) of these elements in the new approach for CL(A) calculation. Likewise, accurate depiction of atmospheric deposition levels can prove useful for evaluation of lake runoff estimates on which estimates of CL(A) are contingent. While CL(A) are low and exceedance may occur according to projected increases in S deposition in the near-term, S retention appears to be an important feature in many catchments and risk of acidification may be overstated should long-term S retention be occurring in peatlands.

Higher net acid excretion is associated with lower risk of kidney disease progression in patients with diabetes

PubMed Central

Scialla, Julia J.; Asplin, John; Dobre, Mirela; Chang, Alex; Lash, James; Hsu, Chi-yuan; Kallem, Radhakrishna R.; Hamm, L. Lee; Feldman, Harold I.; Chen, Jing; Appel, Lawrence; Anderson, Cheryl A. M.; Wolf, Myles

2017-01-01

Higher diet-dependent nonvolatile acid load is associated with faster chronic kidney disease (CKD) progression, but most studies have used estimated acid load or measured only components of the gold-standard, net acid excretion (NAE). Here we measured NAE as the sum of urine ammonium and titratable acidity in 24 hour urines from a random subset of 980 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. In multivariable models accounting for demographics, comorbidity and kidney function, higher NAE was significantly associated with lower serum bicarbonate (0.17 mEq/L lower serum bicarbonate per 10 mEq/day higher NAE), consistent with a larger acid load. Over a median of 6 years follow-up, higher NAE was independently associated with a significantly lower risk of the composite of end stage renal disease or halving of estimated glomerular filtration rate among diabetics (hazard ratio 0.88 per 10 mEq/day higher NAE), but not those without diabetes (hazard ratio 1.04 per 10 mEq/day higher NAE). For comparison, we estimated nonvolatile acid load as net endogenous acid production using self-reported food frequency questionnaires from 2,848 patients and dietary urine biomarkers from 3,385 patients. Higher net endogenous acid production based on biomarkers (urea nitrogen and potassium) was modestly associated with faster CKD progression consistent with prior reports, but only among those without diabetes. Results from the food frequency questionnaires were not associated with CKD progression in any group. Thus, disparate results obtained from analyses of nonvolatile acid load directly measured as NAE and estimated from diet, suggests a novel hypothesis, that the risk of CKD progression related to low NAE, or acid load, may be due to diet-independent changes in acid production in diabetes. PMID:27914710

The ERK pathway regulates Na(+)-HCO(3)(-) cotransport activity in adult rat cardiomyocytes.

PubMed

Baetz, Delphine; Haworth, Robert S; Avkiran, Metin; Feuvray, Danielle

2002-11-01

The sarcolemmal Na(+)-HCO cotransporter (NBC) is stimulated by intracellular acidification and acts as an acid extruder. We examined the role of the ERK pathway of the MAPK cascade as a potential mediator of NBC activation by intracellular acidification in the presence and absence of angiotensin II (ANG II) in adult rat ventricular myocytes. Intracellular pH (pH(i)) was recorded with the use of seminaphthorhodafluor-1. The NH method was used to induce an intracellular acid load. NBC activation was significantly decreased with the ERK inhibitors PD-98059 and U-0126. NBC activity after acidification was increased in the presence of ANG II (pH(i) range of 6.75-7.00). ANG II plus PD-123319 (AT(2) antagonist) still increased NBC activity, whereas ANG II plus losartan (AT(1) antagonist) did not affect it. ERK phosphorylation (measured by immunoblot analysis) during intracellular acidification was increased by ANG II, an effect that was abolished by losartan and U-0126. In conclusion, the MAPK(ERK)-dependent pathway facilitates the rate of pH(i) recovery from acid load through NBC activity and is involved in the AT(1) receptor-mediated stimulation of such activity by ANG II.

Docosahexaenoic acid loaded lipid nanoparticles with bactericidal activity against Helicobacter pylori.

PubMed

Seabra, Catarina Leal; Nunes, Cláudia; Gomez-Lazaro, Maria; Correia, Marta; Machado, José Carlos; Gonçalves, Inês C; Reis, Celso A; Reis, Salette; Martins, M Cristina L

2017-03-15

Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid present in fish oil, has been described as a promising molecule to the treatment of Helicobacter pylori gastric infection. However, due to its highly unsaturated structure, DHA can be easily oxidized loosing part of its bioactivity. This work aims the nanoencapsulation of DHA to improve its bactericidal efficacy against H. pylori. DHA was loaded into nanostructured lipid carriers (NLC) produced by hot homogenization and ultrasonication using a blend of lipids (Precirol ATO5 ® , Miglyol-812 ® ) and a surfactant (Tween 60 ® ). Homogeneous NLC with 302±14nm diameter, -28±3mV surface charge (dynamic and electrophoretic light scattering) and containing 66±7% DHA (UV/VIS spectroscopy) were successfully produced. Bacterial growth curves, performed over 24h in the presence of different DHA concentrations (free or loaded into NLC), demonstrated that nanoencapsulation enhanced DHA bactericidal effect, since DHA-loaded NLC were able to inhibit H. pylori growth in a much lower concentrations (25μM) than free DHA (>100μM). Bioimaging studies, using scanning and transmission electron microscopy and also imaging flow cytometry, demonstrated that DHA-loaded NLC interact with H. pylori membrane, increasing their periplasmic space and disrupting membrane and allowing the leakage of cytoplasmic content. Furthermore, the developed nanoparticles are not cytotoxic to human gastric adenocarcinoma cells at bactericidal concentrations. DHA-loaded NLC should, therefore, be envisaged as an alternative to the current treatments for H. pylori infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimates of critical acid loads and exceedances for forest soils across the conterminous United States

Treesearch

Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers; Timothy J. Sullivan; Harbin Li

2007-01-01

Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A...

Covalent and non-covalent curcumin loading in acid-responsive polymeric micellar nanocarriers

NASA Astrophysics Data System (ADS)

Gao, Min; Chen, Chao; Fan, Aiping; Zhang, Ju; Kong, Deling; Wang, Zheng; Zhao, Yanjun

2015-07-01

Poor aqueous solubility, potential degradation, rapid metabolism and elimination lead to low bioavailability of pleiotropic impotent curcumin. Herein, we report two types of acid-responsive polymeric micelles where curcumin was encapsulated via both covalent and non-covalent modes for enhanced loading capacity and on-demand release. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a hydrazone linker, generating two conjugates differing in architecture (single-tail versus double-tail) and free curcumin was encapsulated therein. The two micelles exhibited similar hydrodynamic size at 95 ± 3 nm (single-tail) and 96 ± 3 nm (double-tail), but their loading capacities differed significantly at 15.0 ± 0.5% (w/w) (single-tail) and 4.8 ± 0.5% (w/w) (double-tail). Under acidic sink conditions (pH 5.0 and 6.0), curcumin displayed a faster release from the single-tail nanocarrier, which was correlated to a low IC50 of 14.7 ± 1.6 (μg mL-1) compared to the value of double-tail micelle (24.9 ± 1.3 μg mL-1) in HeLa cells. The confocal imaging and flow cytometry analysis demonstrated a superior capability of single-tail micelle for intracellular curcumin delivery, which was a consequence of the higher loading capacity and lower degree of mPEG surface coverage. In conclusion, the dual loading mode is an effective means to increase the drug content in the micellar nanocarriers whose delivery efficiency is highly dependent on its polymer-drug conjugate architecture. This strategy offers an alternative nanoplatform for intracellularly delivering impotent hydrophobic agents (i.e. curcumin) in an efficient stimuli-triggered way, which is valuable for the enhancement of curcumin’s efficacy in managing a diverse range of disorders.

Antimicrobial activity of a new synthetic peptide loaded in polylactic acid or poly(lactic-co-glycolic) acid nanoparticles against Pseudomonas aeruginosa, Escherichia coli O157:H7 and methicillin resistant Staphylococcus aureus (MRSA)

NASA Astrophysics Data System (ADS)

Cruz, J.; Flórez, J.; Torres, R.; Urquiza, M.; Gutiérrez, J. A.; Guzmán, F.; Ortiz, C. C.

2017-03-01

Nanocarrier systems are currently being developed for peptide, protein and gene delivery to protect them in the blood circulation and in the gastrointestinal tract. Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with a new antimicrobial GIBIM-P5S9K peptide were obtained by the double emulsion solvent extraction/evaporation method. PLA- and PLGA-NPs were spherical with sizes between 300 and 400 nm for PLA and 200 and 300 nm for PLGA and <0.3 polydispersity index as determined by dynamic light scattering and scanning electron microscopy), having the zeta potential of >20 mV. The peptide-loading efficiency of PLA-NP and PLGA-NPs was 75% and 55%, respectively. PLA- and PLGA-NPs released around 50% of this peptide over 8 h. In 10% human sera the size of peptide loaded PLA- and PLGA-NPs increased between 25.2% and 39.3%, the PDI changed from 3.2 to 5.1 and the surface charge from -7.15 to 14.6 mV. Both peptide loaded PLA- and PLGA-NPs at 0.5 μM peptide concentration inhibited the growth of Escherichia coli O157:H7 (E. coli O157:H7), methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. aeruginosa (P. aeruginosa). In contrast, free peptide inhibited at 10 μM but did not inhibit at 0.5 and 1 μM. These PLA- and PLGA-NPs presented <10% hemolysis indicating that they are hemocompatible and promising for delivery and protection system of GIBIM-P5S9K peptide.

An in vitro assessment of the effect of load and pH on wear between opposing enamel and dentine surfaces.

PubMed

Ranjitkar, Sarbin; Kaidonis, John A; Townsend, Grant C; Vu, Anh M; Richards, Lindsay C

2008-11-01

Previous in vitro studies have described the wear characteristics of specimens in which enamel has been opposed to enamel and dentine opposed to dentine. The aim of this study was to assess the characteristics of wear between specimens in which enamel was opposed to dentine at loads simulating attrition and at pH values simulating different erosive environments. It was hypothesized that enamel would wear more slowly than dentine under all conditions. Opposing enamel and dentine specimens from 57 human third molar teeth were worn in electromechanical machines with various loads (32, 62 and 100 N) and lubricants (pH 1.2, 3.0 and 6.1). Tooth wear was quantified by measuring reduction in dentine volume over time using a 3D profilometer. Qualitative assessment was also carried out using scanning electron microscopy. Dentine wear increased with increasing load, and dentine wear was faster at pH 1.2 than at pH 3.0 or 6.1 for all loads tested. Interestingly, enamel wore more rapidly than dentine at pH 1.2 under all loads. At pH values of 3.0 and 6.1, enamel wear rates were not measurably different from zero and they were less than wear rates for opposing dentine specimens at all loads. Micrographic assessment showed extensive surface destruction of dentine wear facets due to erosion at pH 1.2. Dentine wear facets were smoother at pH 3.0 that at pH 6.1. When enamel wears against dentine in an acidic environment enamel will wear more rapidly at very low pH, while under less acid conditions dentine will wear faster than enamel.

Studies on acid-base status (Stewart's model) of young camels (Camelus dromedarius) after acid-load with NH4Cl.

PubMed

Elkhair, Nawal M; Hartmann, Helmut

2010-01-01

The identification of the reference values of Stewart variables and the changes in the acid-base status of the blood and urine in relation to the age after acid-load were studied in desert species of camels. 14 healthy young camels (age: 3-5 months) and 22 adult camels (age: 5-8 years) were used to provide the reference and percentile ranges of the Stewart variables. In the experiments, 24 healthy young camels (age: < 3-5 months) were infused with 5M NH4Cl solution (dose: 1.0 ml/kg) through a permanent intravenous catheter. Venous blood and urine samples were collected before infusion (0 hours). After the start of infusion, venous blood samples were collected at 2, 4, 6, 8 and 24 hours, and urine samples were collected at 8, 24 and 48 hours. Blood and urine samples were used for the determination of the various acid-base parameters, including the non-respiratory Stewart variables. The reference range of serum-[strong ion difference = SID3] was 39-52 mmol/l for all age groups. The reference values of serum-[acid total = A-] were between 10-17 mmol/l for all age groups. Serum-[Atotprotein] and -[Atot-albumin] showed a reference range of 19-24 mmol/I and 20-28 mmol/l, respectively. By 2-8 hours after the NH4Cl-load, the Stewart variables (serum-[SID3] and serum-[A(tot-protein)]) decreased significantly, and as a consequence, the blood pH decreased. Generally, the loaded young camels showed a transient moderate hyperchloraemic acidosis with a slight hypoproteinaemic alkalosis. These malfunctions were accompanied by increased renal fractional excretion of chloride and sodium and decreased urine pH. The identified reference values of the Stewart variables can be used for the clinical diagnosis of acid-base disturbances in camels. With the assistance of the non-respiratory Stewart variables ([SID3] and [Atot]), we can detect the determining influence of strong electrolytes (Na+, K+ and Cl-) and weak acids (proteins, Pi) on the physiological and pathological acid-base status of the animals.

Bile Acid-Based Drug Delivery Systems for Enhanced Doxorubicin Encapsulation: Comparing Hydrophobic and Ionic Interactions in Drug Loading and Release.

PubMed

Cunningham, Alexander J; Robinson, Mattieu; Banquy, Xavier; Leblond, Jeanne; Zhu, X X

2018-03-05

Doxorubicin (Dox) is a drug of choice in the design of drug delivery systems directed toward breast cancers, but is often limited by loading and control over its release from polymer micelles. Bile acid-based block copolymers present certain advantages over traditional polymer-based systems for drug delivery purposes, since they can enable a higher drug loading via the formation of a reservoir through their aggregation process. In this study, hydrophobic and electrostatic interactions are compared for their influence on Dox loading inside cholic acid based block copolymers. Poly(allyl glycidyl ether) (PAGE) and poly(ethylene glycol) (PEG) were grafted from the cholic acid (CA) core yielding a star-shaped block copolymer with 4 arms (CA-(PAGE- b-PEG) 4 ) and then loaded with Dox via a nanoprecipitation technique. A high Dox loading of 14 wt % was achieved via electrostatic as opposed to hydrophobic interactions with or without oleic acid as a cosurfactant. The electrostatic interactions confer a pH responsiveness to the system. 50% of the loaded Dox was released at pH 5 in comparison to 12% at pH 7.4. The nanoparticles with Dox loaded via hydrophobic interactions did not show such a pH responsiveness. The systems with Dox loaded via electrostatic interactions showed the lowest IC 50 and highest cellular internalization, indicating the pre-eminence of this interaction in Dox loading. The blank formulations are biocompatible and did not show cytotoxicity up to 0.17 mg/mL. The new functionalized star block copolymers based on cholic acid show great potential as drug delivery carriers.

Accumulation of propionic acid during consecutive batch anaerobic digestion of commercial food waste.

PubMed

Capson-Tojo, Gabriel; Ruiz, Diane; Rouez, Maxime; Crest, Marion; Steyer, Jean-Philippe; Bernet, Nicolas; Delgenès, Jean-Philippe; Escudié, Renaud

2017-12-01

The objective of this study was to test three different alternatives to mitigate the destabilizing effect of accumulation of ammonia and volatile fatty acids during food waste anaerobic digestion. The three options tested (low temperature, co-digestion with paper waste and trace elements addition) were compared using consecutive batch reactors. Although methane was produced efficiently (∼500ml CH 4 gVS -1 ; 16l CH 4 lreactor -1 ), the concentrations of propionic acid increased gradually (up to 21.6gl -1 ). This caused lag phases in the methane production and eventually led to acidification at high substrate loads. The addition of trace elements improved the kinetics and allowed higher substrate loads, but could not avoid propionate accumulation. Here, it is shown for the first time that addition of activated carbon, trace elements and dilution can favor propionic acid consumption after its accumulation. These promising options should be optimized to prevent propionate accumulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation and in vitro characterization of gallic acid-loaded human serum albumin nanoparticles

NASA Astrophysics Data System (ADS)

Mohammad-Beigi, Hossein; Shojaosadati, Seyed Abbas; Morshedi, Dina; Arpanaei, Ayyoob; Marvian, Amir Tayaranian

2015-04-01

Gallic acid (GA), as an antioxidant and antiparkinson agent, was loaded onto cationic human serum albumin nanoparticles (HSA NPs). Polyethylenimine (PEI)-coated HSA (PEI-HSA) NPs were prepared using three different methods: (I) coating negatively charged HSA NPs with positively charged PEI through attractive electrostatic interactions, (II) coating HSA NPs with PEI via covalent amide bond formation using N-(3-dimethylaminopropyl)- N-ethylcarbodiimide hydrochloride, and (III) coating HSA NPs with PEI via covalent bonding using glutaraldehyde for linking amine groups of PEI and amine groups of albumin NPs. Method II was selected since it resulted in a higher shift in the zeta potential value (mV) and less zeta potential value deviation, and also less size polydispersity. GA was loaded by adsorption onto the surface of PEI-HSA NPs of two different sizes: 117 ± 2.9 nm (PEI-P1) and 180 ± 3.1 nm (PEI-P2) NPs. Both GA-entrapment and GA-loading efficiencies increased slightly with the increasing size of NPs, and were affected intensely by the mass ratio of GA to PEI-HSA NPs. Free radical scavenging of GA was quantified based on the 2,2-diphenyl-1-picrylhydrazyl method. The obtained results showed that GA remains active during the preparation of GA-loaded PEI-HSA NPs. The cytotoxicities of HSA, PEI-HSA, and GA-loaded PEI-HSA NPs on the PC-12 cells, as the neuroendocrine cell line, were measured. Our results indicate that positively charged PEI-HSA NPs are good candidates for efficient and safe delivery of GA to the brain.

Bifunctional viscous nanovesicles co-loaded with resveratrol and gallic acid for skin protection against microbial and oxidative injuries.

PubMed

Vitonyte, Justina; Manca, Maria Letizia; Caddeo, Carla; Valenti, Donatella; Peris, Josè Esteban; Usach, Iris; Nacher, Amparo; Matos, Maria; Gutiérrez, Gemma; Orrù, Germano; Fernàndez-Busquets, Xavier; Fadda, Anna Maria; Manconi, Maria

2017-05-01

Resveratrol and gallic acid were co-loaded in phospholipid vesicles aiming at protecting the skin from external injuries, such as oxidative stress and microbial infections. Liposomes were prepared using biocompatible phospholipids dispersed in water. To improve vesicle stability and applicability, the phospholipids and the phenols were dispersed in water/propylene glycol or water/glycerol, thus obtaining PEVs and glycerosomes, respectively. The vesicles were characterized by size, morphology, physical stability, and their therapeutic efficacy was investigated in vitro. The vesicles were spherical, unilamellar and small in size: liposomes and glycerosomes were around 70nm in diameter, while PEVs were larger (∼170nm). The presence of propylene glycol or glycerol increased the viscosity of the vesicle systems, positively affecting their stability. The ability of the vesicles to promote the accumulation of the phenols (especially gallic acid) in the skin was demonstrated, as well as their low toxicity and great ability to protect keratinocytes and fibroblasts from oxidative damage. Additionally, an improvement of the antimicrobial activity of the phenols was shown against different skin pathogens. The co-loading of resveratrol and gallic acid in modified phospholipid vesicles represents an innovative, bifunctional tool for preventing and treating skin affections. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and evaluation of microparticles from thiolated polymers via air jet milling.

PubMed

Hoyer, Herbert; Schlocker, Wolfgang; Krum, Kafedjiiski; Bernkop-Schnürch, Andreas

2008-06-01

Microparticles were formulated by incorporation of the model protein horseradish peroxidase in (thiolated) chitosan and (thiolated) poly(acrylic acid) via co-precipitation. Dried protein/polymer complexes were ground with an air jet mill and resulting particles were evaluated regarding size distribution, shape, zeta potential, drug load, protein activity, release pattern, swelling behaviour and cytotoxicity. The mean particle size distribution was 0.5-12 microm. Non-porous microparticles with a smooth surface were prepared. Microparticles from (thiolated) chitosan had a positive charge whereas microparticles from (thiolated) poly(acrylic acid) were negatively charged. The maximum protein load for microparticles based on chitosan, chitosan-glutathione (Ch-GSH), poly(acrylic acid) (PAA) and for poly(acrylic acid)-glutathione (PAA-GSH) was 7+/-1%, 11+/-2%, 4+/-0.2% and 7+/-2%, respectively. The release profile of all microparticles followed a first order release kinetic. Chitosan (0.5mg), Ch-GSH, PAA and PAA-GSH particles showed a 31.4-, 13.8-, 54.2- and a 42.2-fold increase in weight, respectively. No significant cytotoxicity could be found. Thiolated microparticles prepared by jet milling technique were shown to be stable and to have controlled drug release characteristics. After further optimizations the preparation method described here might be a useful tool for the production of protein loaded drug delivery systems.

Pre-aeration of food waste to augment acidogenic process at higher organic load: Valorizing biohydrogen, volatile fatty acids and biohythane.

PubMed

Sarkar, Omprakash; Venkata Mohan, S

2017-10-01

Application of pre-aeration (AS) to waste prior to feeding was evaluated on acidogenic process in a semi-pilot scale biosystem for the production of biobased products (biohydrogen, volatile fatty acids (VFA) and biohythane) from food waste. Oxygen assisted in pre-hydrolysis of waste along with the suppression of methanogenic activity resulting in enhanced acidogenic product formation. AS operation resulted in 97% improvement in hydrogen conversion efficiency (HCE) and 10% more VFA production than the control. Increasing the organic load (OL) of food waste in association with AS application improved the productivity. The application of AS also influenced concentration and composition of fatty acid. Highest fraction of acetic (5.3g/l), butyric (0.7g/l) and propionic acid (0.84g/l) was achieved at higher OL (100g COD/l) with good degree of acidification (DOA). AS strategy showed positive influence on biofuel (biohydrogen and biohythane) production along with the biosynthesis of short chain fatty acids functioning as a low-cost pretreatment strategy in a single stage bioprocess. Copyright © 2017 Elsevier Ltd. All rights reserved.

The acidity of early pregnancy diet and risk of gestational diabetes mellitus.

PubMed

Saraf-Bank, Sahar; Tehrani, Hotav; Haghighatdoost, Fahimeh; Moosavian, Seyedeh Parisa; Azadbakht, Leila

2017-10-03

Recently, an increasing interest has been addressed to the acid-base imbalance in the pathogenesis of diabetes while we are not aware of any study among patients affected by gestational diabetes mellitus (GDM). Therefore, the purpose of present study was to reveal the potential relation between dietary acid load (DAL) and glycemic indices, lipid profiles and GDM odds ratio among Iranian pregnant women with GDM. This case-control study (hospital-based setting) was performed in singleton fetus pregnant women; healthy (n = 263) and GDM (n = 200), aged 22-44 years, and between weeks 5-28 of pregnancy. Three-day 24-h dietary records were applied to determine usual intakes of women. The tertiles of protein to potassium ratio (Pr/K) and potential renal acid load (PRAL) were calculated and used for statistical analyses. Across tertiles of both DAL scores, fasting blood sugar, HbA1C, total cholesterol and LDL-C increased significantly. Diastolic blood pressure of participants significantly increased only across the tertiles of Pr/K ratio. Participants in the highest tertile of Pr/K and PRAL had more than 7 (OR = 7.60; 95% CI: 3.43-16.84) and 9 times (OR = 9.27; 95% CI: 4.00-21.46) increased odds of gestational diabetes mellitus, respectively. Women with higher scores of DAL were more likely to have gestational diabetes mellitus during pregnancy. Copyright © 2017. Published by Elsevier Ltd.

Spatial boundary of urban ‘acid islands’ in southern China

PubMed Central

Du, E.; de Vries, W.; Liu, X.; Fang, J.; Galloway, J. N.; Jiang, Y.

2015-01-01

Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China’s forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban ‘acid islands’ with a critical radius of approximately 70 km in southern China, receiving potential acid loads of more than 2 keq ha−1 yr−1. These urban acid islands covered an area of 0.70 million km2, accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China. PMID:26211880

Spatial boundary of urban 'acid islands' in southern China.

PubMed

Du, E; de Vries, W; Liu, X; Fang, J; Galloway, J N; Jiang, Y

2015-07-27

Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China's forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban 'acid islands' with a critical radius of approximately 70 km in southern China, receiving potential acid loads of more than 2 keq ha(-1) yr(-1). These urban acid islands covered an area of 0.70 million km(2), accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China.

Effects of attrition, prior acid-etching, and cyclic loading on the bond strength of a self-etching adhesive system to dentin.

PubMed

Shinkai, Koichi; Ebihara, Takashi; Shirono, Manabu; Seki, Hideaki; Wakaki, Suguru; Suzuki, Masaya; Suzuki, Shiro; Katoh, Yoshiroh

2009-03-01

The purpose of this study was to evaluate the effects of dentin attrition, phosphoric acid etching, and cyclic loading on the microtensile bond strength (microTBS) of a self-etching adhesive system to dentin. Flat dentin surfaces of human molars were assigned to eight experimental groups based on those with or without attrition, prior acid-etching, and cyclic loading. Resin composite paste was placed and polymerized after the bonding procedure according to manufacturer's instructions. The specimens were subjected to microTBS testing at a crosshead speed of 0.5 mm/min. Results showed that the minimum mean value of microTBS was 14.9 MPa in the group without attrition and acid-etching but with loading, while the maximum mean value of microTBS was 40.0 MPa in the group without attrition and loading but with acid etching. Therefore, the value of microTBS to dentin without attrition was significantly decreased by cyclic loading but that to dentin with attrition was not affected.

Loading and release mechanisms of a biocide in polystyrene-block-poly(acrylic acid) block copolymer micelles.

PubMed

Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

2008-07-24

The kinetics of loading of polystyrene197-block-poly(acrylic acid)47 (PS197-b-PAA47) micelles, suspended in water, with thiocyanomethylthiobenzothiazole biocide and its subsequent release were investigated. Loading of the micelles was found to be a two-step process. First, the surface of the PS core of the micelles is saturated with biocide, with a rate determined by the transfer of solid biocide to micelles during transient micelle-biocide contacts. Next, the biocide penetrates as a front into the micelles, lowering the Tg in the process (non-Fickian case II diffusion). The slow rate of release is governed by the height of the energy barrier that a biocide molecule must overcome to pass from PS into water, resulting in a uniform biocide concentration within the micelle, until Tg is increased to the point that diffusion inside the micelles becomes very slow. Maximum loading of biocide into micelles is approximately 30% (w/w) and is achieved in 1 h. From partition experiments, it can be concluded that the biocide has a similar preference for polystyrene as for ethylbenzene over water, implying that the maximum loading is governed by thermodynamics.

Persistence of Escherichia coli O157:H7 during pilot-scale processing of iceberg lettuce using flume water containing peroxyacetic acid-based sanitizers and various organic loads.

PubMed

Davidson, Gordon R; Kaminski-Davidson, Chelsea N; Ryser, Elliot T

2017-05-02

In order to minimize cross-contamination during leafy green processing, chemical sanitizers are routinely added to the wash water. This study assessed the efficacy of peroxyacetic acid and mixed peracid against E. coli O157:H7 on iceberg lettuce, in wash water, and on equipment during simulated commercial production in a pilot-scale processing line using flume water containing various organic loads. Iceberg lettuce (5.4kg) inoculated to contain 10 6 CFU/g of a 4-strain cocktail of non-toxigenic, GFP-labeled, ampicillin-resistant E. coli O157:H7, was shredded using a commercial shredder, step-conveyed to a flume tank, washed for 90s using water alone or two different sanitizing treatments (50ppm peroxyacetic acid or mixed peracid) in water containing organic loads of 0, 2.5, 5 or 10% (w/v) blended iceberg lettuce, and then dried using a shaker table and centrifugal dryer. Thereafter, three 5.4-kg batches of uninoculated iceberg lettuce were identically processed. Various product (25g) and water (50ml) samples collected during processing along with equipment surface samples (100cm 2 ) from the flume tank, shaker table and centrifugal dryer were then assessed for numbers of E. coli O157:H7. Organic load rarely impacted (P>0.05) the efficacy of either peroxyacetic acid or mixed peracid, with typical reductions of >5logCFU/ml in wash water throughout processing for all organic loads. Increases in organic load in the wash water corresponded to changes in total solids, chemical oxygen demand, turbidity, maximum filterable volume, and oxidation/reduction potential. After 90s of exposure to flume water, E. coli O157:H7 reductions on inoculated lettuce ranged from 0.97 to 1.74logCFU/g using peroxyacetic acid, with an average reduction of 1.35logCFU/g for mixed peracid. E. coli O157:H7 persisted on all previously uninoculated lettuce following the inoculated batch, emphasizing the need for improved intervention strategies that can better ensure end-product safety. Copyright © 2017 Elsevier B.V. All rights reserved.

Fumaric Acid Production from Alkali-Pretreated Corncob by Fed-Batch Simultaneous Saccharification and Fermentation Combined with Separated Hydrolysis and Fermentation at High Solids Loading.

PubMed

Li, Xin; Zhou, Jin; Ouyang, Shuiping; Ouyang, Jia; Yong, Qiang

2017-02-01

Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.

Biliary copper excretion by hepatocyte lysosomes in the rat. Major excretory pathway in experimental copper overload

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gross, J.B. Jr.; Myers, B.M.; Kost, L.J.

1989-01-01

We investigated the hypothesis that lysosomes are the main source of biliary copper in conditions of hepatic copper overload. We used a rat model of oral copper loading and studied the relationship between the biliary output of copper and lysosomal hydrolases. Male Sprague-Dawley rats were given tap water with or without 0.125% copper acetate for up to 36 wk. Copper loading produced a 23-fold increase in the hepatic copper concentration and a 30-65% increase in hepatic lysosomal enzyme activity. Acid phosphatase histochemistry showed that copper-loaded livers contained an increased number of hepatocyte lysosomes; increased copper concentration of these organelles wasmore » confirmed directly by both x ray microanalysis and tissue fractionation. The copper-loaded rats showed a 16-fold increase in biliary copper output and a 50-300% increase in biliary lysosomal enzyme output. In the basal state, excretory profiles over time were similar for biliary outputs of lysosomal enzymes and copper in the copper-loaded animals but not in controls. After pharmacologic stimulation of lysosomal exocytosis, biliary outputs of copper and lysosomal hydrolases in the copper-loaded animals remained coupled: injection of colchicine or vinblastine produced an acute rise in the biliary output of both lysosomal enzymes and copper to 150-250% of baseline rates. After these same drugs, control animals showed only the expected increase in lysosomal enzyme output without a corresponding increase in copper output. We conclude that the hepatocyte responds to an increased copper load by sequestering excess copper in an increased number of lysosomes that then empty their contents directly into bile. The results provide direct evidence that exocytosis of lysosomal contents into biliary canaliculi is the major mechanism for biliary copper excretion in hepatic copper overload.« less

The role of low acid load in vegetarian diet on bone health: a narrative review.

PubMed

Burckhardt, Peter

2016-01-01

Vegetarian and vegan diets contain low amounts of protein and calcium. For this reason they are supposed to cause low bone mineral density (BMD) and osteoporosis. But this is not the case, except for vegans with a particularly low calcium intake. The absence of osteoporosis or low BMD can be explained by the low acid load of these diets. Nutritional acid load is negatively correlated with bone mineral density (BMD) and positively with fracture risk. Low acid load is correlated with lower bone resorption and higher BMD. It is linked to high intake of potassium-rich nutrients, such as fruits and vegetables, as found in vegetarian diets. The total nutritional acid load, which not only depends on the potassium content of the nutrition, was recently assessed in several studies on vegetarian and vegan diets and was found to be very low or absent, while the diet of Western-style omnivores produces daily 50 to 70 mEq of acid. This might be an important factor for the protection of vegetarians from osteoporosis.

Effects of a gradually increased load of fish waste silage in co-digestion with cow manure on methane production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solli, Linn, E-mail: linn.solli@bioforsk.no; Bergersen, Ove; Sørheim, Roald

2014-08-15

Highlights: • New results from continuous anaerobic co-digestion of fish waste silage (FWS) and cow manure (CM). • Co-digestion of FWS and CM has a high biogas potential. • Optimal mixing ratio of FWS/CM is 13–16/87–84 volume%. • High input of FWS leads to accumulation of NH4+ and VFAs and process failure. - Abstract: This study examined the effects of an increased load of nitrogen-rich organic material on anaerobic digestion and methane production. Co-digestion of fish waste silage (FWS) and cow manure (CM) was studied in two parallel laboratory-scale (8 L effective volume) semi-continuous stirred tank reactors (designated R1 andmore » R2). A reactor fed with CM only (R0) was used as control. The reactors were operated in the mesophilic range (37 °C) with a hydraulic retention time of 30 days, and the entire experiment lasted for 450 days. The rate of organic loading was raised by increasing the content of FWS in the feed stock. During the experiment, the amount (volume%) of FWS was increased stepwise in the following order: 3% – 6% – 13% – 16%, and 19%. Measurements of methane production, and analysis of volatile fatty acids, ammonium and pH in the effluents were carried out. The highest methane production from co-digestion of FWS and CM was 0.400 L CH4 gVS{sup −1}, obtained during the period with loading of 16% FWS in R2. Compared to anaerobic digestion of CM only, the methane production was increased by 100% at most, when FWS was added to the feed stock. The biogas processes failed in R1 and R2 during the periods, with loadings of 16% and 19% FWS, respectively. In both reactors, the biogas processes failed due to overloading and accumulation of ammonia and volatile fatty acids.« less

[Synthesis of antibiotic loaded polylactic acid nanoparticles and their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus].

PubMed

Herrera, Mónica Tatiana; Artunduaga, Jhon Jhamilton; Ortiz, Claudia Cristina; Torres, Rodrigo Gonzalo

2017-01-24

Polymeric nanoparticles are promising nanotechnology tools to fight pathogenic bacteria resistant to conventional antibiotics. To synthesize polylactic acid nanoparticles loaded with ofloxacin and vancomycin, and to determine their antibacterial activity against Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA). We synthesized ofloxacin or vancomycin loaded polylactic acid nanoparticles by the emulsification-solvent evaporation method, and characterized them by dynamic light scattering, laser Doppler electrophoresis and scanning electron microscopy. We evaluated in vitro antibacterial activity of ofloxacin- and vancomycin-loaded polylactic acid nanoparticles against E. coli O157:H7 and MRSA using the broth microdilution method. Ofloxacin- and vancomycin-loaded polylactic acid nanoparticles registered a positive surface charge density of 21 mV and an average size lower than 379 nm. In vitro minimum inhibitory concentration (MIC50) of ofloxacin-polylactic acid nanoparticles was 0,001 μg/ml against E. coli O157:H7, i.e., 40 times lower than the free ofloxacin (MIC50: 0.04 μg/ml), indicating enhanced antibacterial activity while the in vitro MIC50 of vancomycin-polylactic acid nanoparticles was 0,005 μg/ml against MRSA, i.e., 100 times lower than that of free vancomycin (MIC50: 0.5 μg/ml). Polylactic acid nanoparticles loaded with ofloxacin and vancomycin showed a higher antibacterial activity. Polymeric nanoparticles are a possible alternative for drug design against pathogenic bacterial strains of public health interest.

An electrochemical impedance spectroscopy study of polymer electrolyte membrane fuel cells electrocatalyst single wall carbon nanohorns-supported.

PubMed

Brandão, Lúcia; Boaventura, Marta; Passeira, Carolina; Gattia, Daniele Mirabile; Marazzi, Renzo; Antisari, Marco Vittori; Mendes, Adélio

2011-10-01

Electrochemical impedance spectroscopy (EIS) was used to study the polymer electrolyte membrane fuel cells (PEMFC) performance when using single wall carbon nanohorns (SWNH) to support Pt nanoparticles. Additionally, as-prepared and oxidized SWNH Pt-supports were compared with conventional carbon black. Two different oxidizing treatments were considered: oxygen flow at 500 degrees C and reflux in an acid solution at 85 degrees C. Both oxidizing treatments increased SWNH surface area; oxygen treatment increased surface area 4 times while acid treatment increased 2.6 times. The increase in surface area should be related to the opening access to the inner tube of SWNH. Acid treatment of SWNH increased chemical fragility and decreased electrocatalyst load in comparison with as-prepared SWNH. On the other hand, the oxygen treated SWNH sample allowed to obtain the highest electrocatalyst load. The use of as-prepared and oxygen treated SWNH showed in both cases catalytic activities 60% higher than using conventional carbon black as electrocatalyst support in PEMFC. Moreover, EIS analysis indicated that the major improvement in performance is related to the cathode kinetics in the as-prepared SWNH sample, while concerning the oxidized SWNH sample, the improvements are related to the electrokinetics in both anode and cathode electrodes. These improvements should be related with differences in the hydrophobic character between SWNH and carbon black.

The role of wall calcium in the extension of cell walls of soybean hypocotyls

NASA Technical Reports Server (NTRS)

Virk, S. S.; Cleland, R. E.

1990-01-01

Calcium crosslinks are load-bearing bonds in soybean (Glycine max (L.) Merr.) hypocotyl cell walls, but they are not the same load-bearing bonds that are broken during acid-mediated cell elongation. This conclusion is reached by studying the relationship between wall calcium, pH and the facilitated creep of frozen-thawed soybean hypocotyl sections. Supporting data include the following observations: 1) 2-[(2-bis-[carboxymethyl]amino-5-methylphenoxy)methyl]-6-methoxy-8-bis[car boxymethyl]aminoquinoline (Quin 2) and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) caused only limited facilitated creep as compared with acid, despite removal of comparable or larger amounts of wall calcium; 2) the pH-response curves for calcium removal and acid-facilitated creep were different; 3) reversible acid-extension occurred even after removal of almost all wall calcium with Quin 2; and 4) growth of abraded sections did not involve a proportional loss of wall calcium. Removal of wall calcium, however, increased the capacity of the walls to undergo acid-facilitated creep. These data indicate that breakage of calcium crosslinks is not a major mechanism of cell-wall loosening in soybean hypocotyl tissues.

Biodegradable Drug-Loaded Hydroxyapatite Nanotherapeutic Agent for Targeted Drug Release in Tumors.

PubMed

Sun, Wen; Fan, Jiangli; Wang, Suzhen; Kang, Yao; Du, Jianjun; Peng, Xiaojun

2018-03-07

Tumor-targeted drug delivery systems have been increasingly used to improve the therapeutic efficiency of anticancer drugs and reduce their toxic side effects in vivo. Focused on this point, doxorubicin (DOX)-loaded hydroxyapatite (HAP) nanorods consisting of folic acid (FA) modification (DOX@HAP-FA) were developed for efficient antitumor treatment. The DOX-loaded nanorods were synthesized through in situ coprecipitation and hydrothermal method with a DOX template, demonstrating a new procedure for drug loading in HAP materials. DOX could be efficiently released from DOX@HAP-FA within 24 h in weakly acidic buffer solution (pH = 6.0) because of the degradation of HAP nanorods. With endocytosis under the mediation of folate receptors, the nanorods exhibited enhanced cellular uptake and further degraded, and consequently, the proliferation of targeted cells was inhibited. More importantly, in a tumor-bearing mouse model, DOX@HAP-FA treatment demonstrated excellent tumor growth inhibition. In addition, no apparent side effects were observed during the treatment. These results suggested that DOX@HAP-FA may be a promising nanotherapeutic agent for effective cancer treatment in vivo.

Kinetic study of dry anaerobic co-digestion of food waste and cardboard for methane production.

PubMed

Capson-Tojo, Gabriel; Rouez, Maxime; Crest, Marion; Trably, Eric; Steyer, Jean-Philippe; Bernet, Nicolas; Delgenès, Jean-Philippe; Escudié, Renaud

2017-11-01

Dry anaerobic digestion is a promising option for food waste treatment and valorization. However, accumulation of ammonia and volatile fatty acids often occurs, leading to inefficient processes and digestion failure. Co-digestion with cardboard may be a solution to overcome this problem. The effect of the initial substrate to inoculum ratio (0.25 to 1gVS·gVS -1 ) and the initial total solids contents (20-30%) on the kinetics and performance of dry food waste mono-digestion and co-digestion with cardboard was investigated in batch tests. All the conditions produced methane efficiently (71-93% of the biochemical methane potential). However, due to lack of methanogenic activity, volatile fatty acids accumulated at the beginning of the digestion and lag phases in the methane production were observed. At increasing substrate to inoculum ratios, the initial acid accumulation was more pronounced and lower cumulative methane yields were obtained. Higher amounts of soluble organic matter remained undegraded at higher substrate loads. Although causing slightly longer lag phases, high initial total solids contents did not jeopardize the methane yields. Cardboard addition reduced acid accumulation and the decline in the yields at increasing substrate loads. However, cardboard addition also caused higher concentrations of propionic acid, which appeared as the most last acid to be degraded. Nevertheless, dry co-digestion of food waste and cardboard in urban areas is demonstrated asan interesting feasible valorization option. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison among model estimates of critical loads of acidic deposition using different sources and scales of input data

Treesearch

T.C. McDonnell; B.J. Cosby; T.J. Sullivan; S.G. McNulty; E.C. Cohen

2010-01-01

The critical load (CL) of acidic atmospheric deposition represents the load of acidity deposited from the atmosphere to the earth’s surface at which harmful acidification effects on sensitive biological receptors are thought to occur. In this study, the CL for forest soils was estimated for 27 watersheds throughout the United States using a steady-state mass balance...

Chitosan-functionalised poly(2-hydroxyethyl methacrylate) core-shell microgels as drug delivery carriers: salicylic acid loading and release.

PubMed

Mahattanadul, Natshisa; Sunintaboon, Panya; Sirithip, Piyawan; Tuchinda, Patoomratana

2016-09-01

This work presents the evaluation of chitosan-functionalised poly(2-hydroxyethyl methacrylate) (CS/PHEMA) core-shell microgels as drug delivery carriers. CS/PHEMA microgels were prepared by emulsifier-free emulsion polymerisation with N,N '-methylenebisacrylamide (MBA) as a crosslinker. The study on drug loading, using salicylic acid (SA) as a model drug, was performed. The results showed that the encapsulation efficiency (EE) increased as drug-to-microgel ratio was increased. Higher EE can be achieved with the increase in degree of crosslinking, by increasing the amount of MBA from 0.01 g to 0.03 g. In addition, the highest EE (61.1%) was observed at pH 3. The highest release of SA (60%) was noticed at pH 2.4, while the lowest one (49.4%) was obtained at pH 7.4. Moreover, the highest release of SA was enhanced by the presence of 0.2 M NaCl. The pH- and ionic-sensitivity of CS/PHEMA could be useful as a sustained release delivery device, especially for oral delivery.

α-Lipoic acid stabilized DTX/IR780 micelles for photoacoustic/fluorescence imaging guided photothermal therapy/chemotherapy of breast cancer.

PubMed

Li, WenTing; Peng, JinRong; Yang, Qian; Chen, LiJuan; Zhang, Lan; Chen, XiaoXin; Qian, ZhiYong

2018-05-01

Micellar nanoparticles have unique advantages as carriers for therapeutic or imaging agents, owing to their smaller size and better penetration of tumors. However, some agents, due to their physical or chemical properties, are difficult to load into micelles. IR780 is one of these agents, and is also a promising near-infrared dye for fluorescence imaging (FI)/photoacoustic imaging (PAI) and cancer photothermal therapy (PTT). Its hydrophobic and high crystallization structure results in limited bioavailability in vivo. It is difficult to load into micelles constructed from an amphiphilic block polymer with relatively low molecular weight. In this study, we use computer simulation and introduce another small biomolecule, α-lipoic acid, into the micelles constructed from a mPEG-PCL copolymer, to lower the energy of molecular interaction between MPEG-PCL and IR780, and expect to enhance the loading capacity of the micelles to IR780. The introduction of α-lipoic acid decreases the energy of molecular interaction between MEPG-PCL and IR780 from -46.18 kJ mol-1 to -196.52 kJ mol-1 and increases the loading capacity and stability of the mPEG-PCL micelles to IR780, which also maintains the loading capacity to DTX. We further construct DTX/IR780 co-loaded mPEG-PCL micelles for FI/PAI dual modal imaging guided PTT/chemotherapy of cancer. By FI and PAI evaluation in vitro and in vivo, we demonstrate that the DTX/IR780 co-loaded micelles can be used as FI and PAI probes. By further evaluating the therapeutic outcome of PTT/chemotherapy co-therapy of breast cancer, we demonstrate that the DTX/IR780 co-loaded mPEG-PCL micelles can serve as promising candidates for FI and PAI guided PTT/chemotherapy of breast cancer.

An acute intake of a walnut-enriched meal improves postprandial adiponectin response in healthy young adults.

PubMed

Lozano, Aquiles; Perez-Martinez, Pablo; Marin, Carmen; Tinahones, Francisco J; Delgado-Lista, Javier; Cruz-Teno, Cristina; Gomez-Luna, Purificacion; Rodriguez-Cantalejo, Fernando; Perez-Jimenez, Francisco; Lopez-Miranda, Jose

2013-12-01

A deficit in adiponectin plays an important causal role in insulin resistance and metabolic syndrome. We hypothesized that as seen during the fasting state, the intake of a walnut-enriched meal increased postprandial adiponectin. Twenty-one healthy white men followed a 4-week baseline diet and then consumed 3 fat-loaded meals that included 1 g fat/kg body weight (65% fat) according to a randomized crossover design: olive oil-enriched meal (22% saturated fatty acids [SFA], 38% monounsaturated fatty acids [MUFA], 4% polyunsaturated fatty acids [PUFA]), butter-enriched meal (35% SFA, 22% MUFA, 4% PUFA), and walnut-enriched meal (20% SFA, 24% MUFA, 16% PUFA, and 4% α-linolenic acid). Leptin, resistin, adiponectin, and free fatty acids were determined at 0, 3, 6, and 8.5 hours after the fat load. After the walnut-enriched meal, plasma adiponectin concentrations were higher at 3 and 6 hours (P = .011, P = .046, respectively) compared with the butter-enriched meal and higher at 6 hours compared with the olive oil-enriched meal (P = .036). Free fatty acid levels decreased from baseline at 3 hours after the walnut-enriched meal (P = .001). No differences were observed between the 3 meals for leptin and resistin responses. Our data confirmed a beneficial profile in the postprandial response to walnuts, source of omega-3 PUFA with an increased postprandial adiponectin and lower postprandial free fatty acid responses. These findings suggest that the postprandial state is important for understanding the possible cardioprotective effects associated with omega-3 PUFA dietary fat. © 2013 Elsevier Inc. All rights reserved.

Synthesis and characterization of hydrogel films of carboxymethyl tamarind gum using citric acid.

PubMed

Mali, Kailas K; Dhawale, Shashikant C; Dias, Remeth J

2017-12-01

The objective of this study was to synthesize and characterize citric acid crosslinked carboxymethyl tamarind gum (CMTG) hydrogels films. The hydrogel films were characterized by Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, solid state 13 C-nuclear magnetic resonance ( 13 C NMR) spectroscopy and differential scanning calorimeter (DSC). The prepared hydrogel films were evaluated for the carboxyl content and swelling ratio. The model drug moxifloxacin hydrochloride was loaded into hydrogels films and drug release was studied at pH 7.4. The hemolysis assay was used to study the biocompatibility of hydrogel films. The results of ATR-FTIR, solid state 13 C NMR and DSC confirmed the formation of ester crosslinks between citric acid and CMTG. The total carboxyl content of hydrogel film was found to be decreased when amount of CMTG was increased. The swelling of hydrogel film was found to be decreased with increase in curing temperature and time. CMTG hydrogel films showed high drug loading with non-Fickian release mechanism suggesting controlled release of drug. The hydrogel films were found to be biocompatible. It can be concluded that the citric acid can be used for the preparation of CMTG hydrogel films. Further, CMTG hydrogel film can be used potentially for controlled release of drug. Copyright © 2017 Elsevier B.V. All rights reserved.

Formulation and characterization of poly(propylacrylic acid)/poly(lactic-co-glycolic acid) blend microparticles for pH-dependent membrane disruption and cytosolic delivery.

PubMed

Fernando, Lawrence P; Lewis, Jamal S; Evans, Brian C; Duvall, Craig L; Keselowsky, Benjamin G

2018-04-01

Poly(lactic-co-glycolic acid) (PLGA) is widely used as a vehicle for delivery of pharmaceutically relevant payloads. PLGA is readily fabricated as a nano- or microparticle (MP) matrix to load both hydrophobic and hydrophilic small molecular drugs as well as biomacromolecules such as nucleic acids and proteins. However, targeting such payloads to the cell cytosol is often limited by MP entrapment and degradation within acidic endolysosomes. Poly(propylacrylic acid) (PPAA) is a polyelectrolyte polymer with the membrane disruptive capability triggered at low pH. PPAA has been previously formulated in various carrier configurations to enable cytosolic payload delivery, but requires sophisticated carrier design. Taking advantage of PPAA functionality, we have incorporated PPAA into PLGA MPs as a simple polymer mixture to enhance cytosolic delivery of PLGA-encapsulated payloads. Rhodamine loaded PLGA and PPAA/PLGA blend MPs were prepared by a modified nanoprecipitation method. Incorporation of PPAA into PLGA MPs had little to no effect on the size, shape, or loading efficiency, and evidenced no toxicity in Chinese hamster ovary epithelial cells. Notably, incorporation of PPAA into PLGA MPs enabled pH-dependent membrane disruption in a hemolysis assay, and a three-fold increased endosomal escape and cytosolic delivery in dendritic cells after 2 h of MP uptake. These results demonstrate that a simple PLGA/PPAA polymer blend is readily fabricated into composite MPs, enabling cytosolic delivery of an encapsulated payload. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1022-1033, 2018. © 2017 Wiley Periodicals, Inc.

Diet-dependent net endogenous acid load of vegan diets in relation to food groups and bone health-related nutrients: results from the German Vegan Study.

PubMed

Ströhle, Alexander; Waldmann, Annika; Koschizke, Jochen; Leitzmann, Claus; Hahn, Andreas

2011-01-01

Dietary composition has been shown to affect acid-base homeostasis and bone health in humans. We investigated the potential renal acid load (PRAL) and the estimated diet-dependent net acid load (net endogenous acid production, NEAP) in adult vegans and evaluated the relationships between NEAP, food groups and intake of bone health-related nutrients. The German Vegan Study (GVS) is a cross-sectional study. Data from healthy men (n = 67) and women (n = 87), aged 21-75 years, who fulfilled the study criteria (vegan diet for ≥1 year prior to study start; age ≥18 years, and no pregnancy/childbirth during the last 12 months) were included in the analysis. NEAP values were calculated from diet composition using two models: one based on the protein/potassium quotient and another taking into account an anthropometry-based loss of urinary organic anions. Mean daily intakes of phosphorus, potassium, sodium, magnesium and vitamin C were above, and vitamin D and calcium below Dietary Reference Intake (DRI). Regardless of the model used, the diet in the GVS was characterized by a nearly neutral NEAP. A strong correlation was observed between the NEAP values of the two models (r(s) = 0.873, p < 0.001). Only the consumption of fruits decreased constantly across the increasing quartiles of NEAP. It can be hypothesized that vegan diets do not affect acid-base homeostasis. With respect to bone health, the significance of this finding needs further investigation. Copyright © 2011 S. Karger AG, Basel.

Reversed electrogenic sodium bicarbonate cotransporter 1 is the major acid loader during recovery from cytosolic alkalosis in mouse cortical astrocytes

PubMed Central

Theparambil, Shefeeq M; Naoshin, Zinnia; Thyssen, Anne; Deitmer, Joachim W

2015-01-01

Recovery of intracellular pH from cytosolic alkalosis has been attributed primarily to Cl– coupled acid loaders/base extruders such as Cl–/HCO3– or Cl–/OH– exchangers. We have studied this process in cortical astrocytes from wild-type and transgenic mouse models with gene deletion for the electrogenic sodium bicarbonate cotransporter 1 (NBCe1) and for carbonic anhydrase (CA) isoform II. An acute cytosolic alkalosis was induced by the removal of either CO2/HCO3– or butyric acid, and the subsequent acid loading was analysed by monitoring changes in cytosolic H+ or Na+ using ion-sensitive fluorescent dyes. We have identified that NBCe1 reverses during alkalosis and contributes more than 70% to the rate of recovery from alkalosis by extruding Na+ and HCO3–. After CA inhibition or in CAII-knockout (KO) cells, the rate of recovery was reduced by 40%, and even by 70% in the nominal absence of CO2/HCO3–. Increasing the extracellular K+ concentration modulated the rate of acid loading in wild-type cells, but not in NBCe1-KO cells. Removing chloride had only a minor effect on the recovery from alkalosis. Reversal of NBCe1 by reducing pH/[HCO3–] was demonstrated in astrocytes and in Xenopus oocytes, in which human NBCe1 was heterologously expressed. The results obtained suggest that reversed NBCe1, supported by CAII activity, plays a major role in acid-loading cortical astrocytes to support recovery from cytosolic alkalosis. PMID:25990710

Preparation and physico-chemical properties of hydrogels from carboxymethyl cassava starch crosslinked with citric acid

NASA Astrophysics Data System (ADS)

Boonkham, Sasikan; Sangseethong, Kunruedee; Chatakanon, Pathama; Niamnuy, Chalida; Nakasaki, Kiyohiko; Sriroth, Klanarong

2014-06-01

Recently, environmentally friendly hydrogels prepared from renewable bio-based resources have drawn significant attention from both industrial and academic sectors. In this study, chemically crosslinked hydrogels have been developed from cassava starch which is a bio-based polymer using a non-toxic citric acid as a crosslinking agent. Cassava starch was first modified by carboxymethylation to improve its water absorbency property. The carboxymethyl cassava starch (CMCS) obtained was then crosslinked with citric acid at different concentrations and reaction times. The gel fraction of hydrogels increased progressively with increasing citric acid concentration. Free swelling capacity of hydrogels in de-ionized water, saline solution and buffers at various pHs as well as absorption under load were investigated. The results revealed that swelling behavior and mechanical characteristic of hydrogels depended on the citric acid concentration used in reaction. Increasing citric acid concentration resulted in hydrogels with stronger network but lower swelling and absorption capacity. The cassava starch hydrogels developed were sensitive to ionic strength and pH of surrounding medium, showing much reduced swelling capacity in saline salt solution and acidic buffers.

Morphology and Structure of Amino-fatty Acid Intercalated Montmorillonite

NASA Astrophysics Data System (ADS)

Reyes, Larry; Sumera, Florentino

2015-04-01

Natural clays and its modified forms have been studied for their wide range of applications, including polymer-layered silicate, catalysts and adsorbents. For nanocomposite production, montmorillonite (MMT) clays are often modified with organic surfactants to favor its intermixing with the polymer matrix. In the present study, Na+-montmorillonite (Na+-MMT) was subjected to organo-modification with a protonated 12-aminolauric acid (12-ALA). The amount of amino fatty acid surfactants loaded was 25, 50, 100 and 200% the cation exchange capacity (CEC) of Na+-MMT (25CEC-AMMT, 50CEC-AMMT, 100CEC-AMMT and 200CEC-AMMT). Fatty acid-derived surfactants are an attractive resource of intercalating agents for clays due to their renewability and abundance. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to determine the occurrence of intercalation of 12-ALA and their molecular structure in the clay's silicates. XRD analysis revealed that the interlayer spacing between the alumino-silicate layers increased from 1.25 nm to 1.82 nm with increasing ALA content. The amino fatty acid chains were considered to be in a flat monolayer structure at low surfactant loading, and a bilayered to a pseudotrilayered structure at high surfactant loading. On the other hand, FTIR revealed that the alkyl chains adopt a gauche conformation, indicating their disordered state based on their CH2symmetric and asymmetric vibrations. Thermogravimetric analyses (TGA) allows the determination of the moisture and organic content in clays. Here, TGA revealed that the surfactant in the clay was thermally stable, with Td ranging from 353° C to 417° C. The difference in the melting behavior of the pristine amino fatty acids and confined fatty acids in the interlayer galleries of the clay were evaluated by Differential Scanning Calorimerty (DSC). The melting temperatures (Tm) of the amino fatty acid in the clay were initially found to be higher than those of the free amino fatty acid, but decreased with increasing surfactant loading. This suggested that the amino fatty acid may be tethered to the clay structure via ionic interaction and/or ion-dipole attraction. Significant changes in the clay morphology, particle size and surface charge were observed after organo-modification. Scanning electron microscopy (SEM) revealed that the organo-clays have a disordered and flaky morphology, while the unmodified MMT appeared to be dispersed spherical grains. The effective (Z) diameter of Na+-MMT was found to be ~520 nm, but increased up to ~937 nm upon intercalation of 12-ALA. The zeta potential (ξ) of the clay materials, on the other hand, ranged from -33 mV for undmodified MMT to -16 mv (200CEC-AMMT clay). The possible occupational hazards of working with nanoclays should also be explored. Presently, the MTT-dye reduction assay was performed to determine cell viability of mouse monocyte-macrophages (J774A.1) after direct exposure to the clays. The cytotoxicity of the clays exhibited a chemistry and dose dependent response, with unmodified Na+-MMT as the most cytotoxic while the organo-clays exhibited low toxicity. These results demonstrated the successful intercalation of the surfactant for the production of organophilic clay materials for a wide range of applications.

Nb2O5-γ-Al2O3 nanofibers as heterogeneous catalysts for efficient conversion of glucose to 5-hydroxymethylfurfural

NASA Astrophysics Data System (ADS)

Jiao, Huanfeng; Zhao, Xiaoliang; Lv, Chunxiao; Wang, Yijun; Yang, Dongjiang; Li, Zhenhuan; Yao, Xiangdong

2016-09-01

One-dimensional γ-Al2O3 nanofibers were modified with Nb2O5 to be used as an efficient heterogeneous catalyst to catalyze biomass into 5-hydroxymethylfurfural (5-HMF). At low Nb2O5 loading, the niobia species were well dispersed on γ-Al2O3 nanofiber through Nb-O-Al bridge bonds. The interaction between Nb2O5 precursor and γ-Al2O3 nanofiber results in the niobia species with strong Lewis acid sites and intensive Brønsted acid sites, which made 5-HMF yield from glucose to reach the maximum 55.9~59.0% over Nb2O5-γ-Al2O3 nanofiber with a loading of 0.5~1 wt% Nb2O5 at 150 °C for 4 h in dimethyl sulfoxide. However, increasing Nb2O5 loading could lead to the formation of two-dimensional polymerized niobia species, three-dimensional polymerized niobia species and crystallization, which significantly influenced the distribution and quantity of the Lewis acid sites and Brönst acid sites over Nb2O5-γ-Al2O3 nanofiber. Lewis acid site Nbδ+ played a key role on the isomerization of glucose to fructose, while Brønsted acid sites are more active for the dehydration of generated fructose to 5-HMF. In addition, the heterogeneous Nb2O5-γ-Al2O3 nanofiber catalyst with suitable ratio of Lewis acid to Brönsted sites should display an more excellent catalytic performance in the conversion of glucose to 5-HMF.

Acid deposition and assessment of its critical load for the environmental health of waterbodies in a subtropical watershed, China

NASA Astrophysics Data System (ADS)

Jia, Junjie; Gao, Yang

2017-12-01

Atmospheric acidic deposition in subtropical watersheds poses an environmental risk of causing acidification of aquatic ecosystems. In this study, we evaluated the frequency of acid deposition in a subtropical forest ecosystem and the associated critical loads of acidity for a sensitive aquatic ecosystem. We found that out of 132 rainfall events, 33(25%) were acidic rainfall occurrences. Estimated wet acid deposition (2282.78 eq·ha-1·yr-1), consistent with SO42- and NH4+ deposition, was high in spring and summer and low in autumn and winter. Waterbodies surrounded by mixed wood and citrus orchard experience severe acidification, mostly from S deposition because acidic deposition exceeds the corresponding critical loads of acidity. Modifications that take acid rain deposition into consideration are needed for land-use and agricultural management strategies to improve the environmental health of waterbodies in subtropical watersheds.

A novel in situ hydrophobic ion paring (HIP) formulation strategy for clinical product selection of a nanoparticle drug delivery system.

PubMed

Song, Young Ho; Shin, Eyoung; Wang, Hong; Nolan, Jim; Low, Susan; Parsons, Donald; Zale, Stephen; Ashton, Susan; Ashford, Marianne; Ali, Mir; Thrasher, Daniel; Boylan, Nicholas; Troiano, Greg

2016-05-10

The present studies were aimed at formulating AZD2811-loaded polylactic acid-polyethylene glycol (PLA-PEG) nanoparticles with adjustable release rates without altering the chemical structures of the polymer or active pharmaceutical ingredient (API). This was accomplished through the use of a hydrophobic ion pairing approach. A series of AZD2811-containing nanoparticles with a variety of hydrophobic counterions including oleic acid, 1-hydroxy-2-naphthoic acid, cholic acid, deoxycholic acid, dioctylsulfosuccinic acid, and pamoic acid is described. The hydrophobicity of AZD2811 was increased through formation of ion pairs with these hydrophobic counterions, producing nanoparticles with exceptionally high drug loading-up to five fold higher encapsulation efficiency and drug loading compared to nanoparticles made without hydrophobic ion pairs. Furthermore, the rate at which the drug was released from the nanoparticles could be controlled by employing counterions with various hydrophobicities and structures, resulting in release half-lives ranging from about 2 to 120h using the same polymer, nanoparticle size, and nanoemulsion process. Process recipe variables affecting drug load and release rate were identified, including pH and molarity of quench buffer. Ion pair formation between AZD2811 and pamoic acid as a model counterion was investigated using solubility enhancement as well as nuclear magnetic resonance spectroscopy to demonstrate solution-state interactions. Further evidence for an ion pairing mechanism of controlled release was provided through the measurement of API and counterion release profiles using high-performance liquid chromatography, which had stoichiometric relationships. Finally, Raman spectra of an AZD2811-pamoate salt compared well with those of the formulated nanoparticles, while single components (AZD2811, pamoic acid) alone did not. A library of AZD2811 batches was created for analytical and preclinical characterization. Dramatically improved preclinical efficacy and tolerability data were generated for the pamoic acid lead formulation, which has been selected for evaluation in a Phase 1 clinical trial (ClinicalTrials.gov Identifier NCT 02579226). This work clearly demonstrates the importance of assessing a wide range of drug release rates during formulation screening as a critical step for new drug product development, and how utilizing hydrophobic ion pairing enabled this promising nanoparticle formulation to proceed into clinical development. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of gaseous sulphuric acid on diesel exhaust nanoparticle formation and characteristics.

PubMed

Rönkkö, Topi; Lähde, Tero; Heikkilä, Juha; Pirjola, Liisa; Bauschke, Ulrike; Arnold, Frank; Schlager, Hans; Rothe, Dieter; Yli-Ojanperä, Jaakko; Keskinen, Jorma

2013-10-15

Diesel exhaust gaseous sulphuric acid (GSA) concentrations and particle size distributions, concentrations, and volatility were studied at four driving conditions with a heavy duty diesel engine equipped with oxidative exhaust after-treatment. Low sulfur fuel and lubricant oil were used in the study. The concentration of the exhaust GSA was observed to vary depending on the engine driving history and load. The GSA affected the volatile particle fraction at high engine loads; higher GSA mole fraction was followed by an increase in volatile nucleation particle concentration and size as well as increase of size of particles possessing nonvolatile core. The GSA did not affect the number of nonvolatile particles. At low and medium loads, the exhaust GSA concentration was low and any GSA driven changes in particle population were not observed. Results show that during the exhaust cooling and dilution processes, besides critical in volatile nucleation particle formation, GSA can change the characteristics of all nucleation mode particles. Results show the dual nature of the nucleation mode particles so that the nucleation mode can include simultaneously volatile and nonvolatile particles, and fulfill the previous results for the nucleation mode formation, especially related to the role of GSA in formation processes.

Biaxial fatigue crack propagation behavior of perfluorosulfonic-acid membranes

NASA Astrophysics Data System (ADS)

Lin, Qiang; Shi, Shouwen; Wang, Lei; Chen, Xu; Chen, Gang

2018-04-01

Perfluorosulfonic-acid membranes have long been used as the typical electrolyte for polymer-electrolyte fuel cells, which not only transport proton and water but also serve as barriers to prevent reactants mixing. However, too often the structural integrity of perfluorosulfonic-acid membranes is impaired by membrane thinning or cracks/pinholes formation induced by mechanical and chemical degradations. Despite the increasing number of studies that report crack formation, such as crack size and shape, the underlying mechanism and driving forces have not been well explored. In this paper, the fatigue crack propagation behaviors of Nafion membranes subjected to biaxial loading conditions have been investigated. In particular, the fatigue crack growth rates of flat cracks in responses to different loading conditions are compared, and the impact of transverse stress on fatigue crack growth rate is clarified. In addition, the crack paths for slant cracks under both uniaxial and biaxial loading conditions are discussed, which are similar in geometry to those found after accelerated stress testing of fuel cells. The directions of initial crack propagation are calculated theoretically and compared with experimental observations, which are in good agreement. The findings reported here lays the foundation for understanding of mechanical failure of membranes.

Magnetic Core-Shell Silica Nanoparticles with Large Radial Mesopores for siRNA Delivery.

PubMed

Xiong, Lin; Bi, Jingxu; Tang, Youhong; Qiao, Shi-Zhang

2016-09-01

A novel type of magnetic core-shell silica nanoparticles is developed for small interfering RNA (siRNA) delivery. These nanoparticles are fabricated by coating super-paramagnetic magnetite nanocrystal clusters with radial large-pore mesoporous silica. The amine functionalized nanoparticles have small particle sizes around 150 nm, large radial mesopores of 12 nm, large surface area of 411 m(2) g(-1) , high pore volume of 1.13 cm(3) g(-1) and magnetization of 25 emu g(-1) . Thus, these nanoparticles possess both high loading capacity of siRNA (2 wt%) and strong magnetic response under an external magnetic field. An acid-liable coating composed of tannic acid can further protect the siRNA loaded in these nanoparticles. The coating also increases the dispersion stability of the siRNA-loaded carrier and can serve as a pH-responsive releasing switch. Using the magnetic silica nanoparticles with tannic acid coating as carriers, functional siRNA has been successfully delivered into the cytoplasm of human osteosarcoma cancer cells in vitro. The delivery is significantly enhanced with the aid of the external magnetic field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Skin penetration and retention of L-ascorbic acid 2-phosphate using multilamellar vesicles.

PubMed

Yoo, Juno; Shanmugam, Srinivasan; Song, Chung-Kil; Kim, Dae-Duk; Choi, Han-Gon; Yong, Chul-Soon; Woo, Jong-Soo; Yoo, Bong Kyu

2008-12-01

Transdermal formulation of L-ascorbic acid 2-phosphate magnesium salt (A2P) was prepared using multilamellar vesicles (MLV). A2P was either physically mixed with or entrapped into three different MLVs of neutral, cationic, and anionic liposome vesicles. For the preparation of neutral MLVs, phosphatidylcholine (PC) and cholesterol (CH) were used. For cationic and anionic MLVs, dioleoyl-trimethylammonium-propane and dimyristoyl glycerophosphate were added as surface charge inducers, respectively, in addition to PC and CH. Particle size of the three A2P-loaded MLVs was submicron, and polydispersity index revealed homogenous distribution of the prepared MLVs except neutral ones. Skin penetration study with hairless mouse skin showed that both physical mixtures of A2P with empty MLVs and A2P-loaded MLVs increased penetration of the drug compared to aqueous A2P solution. During the penetration, however, significant amount of the drug was metabolized into L-ascorbic acid, which has no beneficial effect on stimulation of hair growth. Out of the physical mixtures and A2P-loaded MLVs tested, physical mixture of A2P with empty cationic MLV resulted in the greatest skin penetration and retention in hairless mouse skin.

Critical loads of acidity for 90,000 lakes in northern Saskatchewan: A novel approach for mapping regional sensitivity to acidic deposition

NASA Astrophysics Data System (ADS)

Cathcart, H.; Aherne, J.; Jeffries, D. S.; Scott, K. A.

2016-12-01

Atmospheric emissions of sulphur dioxide (SO2) from large point sources are the primary concern for acidic deposition in western Canada, particularly in the Athabasca Oil Sands Region (AOSR) where prevailing winds may potentially carry SO2 over acid-sensitive lakes in northern Saskatchewan. A novel catchment-scale regression kriging approach was used to assess regional sensitivity and critical loads of acidity for the total lake population of northern Saskatchewan (89,947 lakes). Lake catchments were delineated using Thiessen polygons, and surface water chemistry was predicted for sensitivity indicators (calcium, pH, alkalinity, and acid neutralizing capacity). Critical loads were calculated with the steady state water chemistry model using regression-kriged base cations, sulphate, and dissolved organic carbon concentrations modelled from surface water observations (n > 800) and digital landscape-scale characteristics, e.g., climate, soil, vegetation, landcover, and geology maps. A large region (>13,726 km2) of two or more indicators of acid sensitivity (pH < 6 and acid neutralizing capacity, alkalinity, calcium < 50 μeq L-1) and low critical loads < 5 meq m-2 yr-1 were predicted on the Athabasca Basin. Exceedance of critical loads under 2006 modelled total sulphate deposition was predicted for 12% of the lakes (covering an area of 3742 km2), primarily located on the Athabasca Basin, within 100 km of the AOSR. There have been conflicting scientific reports of impacts from atmospheric emissions from the AOSR; the results of this study suggest that catchments in the Athabasca Basin within 100 km of the AOSR have received acidic deposition in excess of their critical loads and many of them may be at risk of ecosystem damage owing to their sensitivity.

The impact of compaction and leachate recirculation on waste degradation in simulated landfills.

PubMed

Ko, Jae Hac; Yang, Fan; Xu, Qiyong

2016-07-01

This study investigated the impact of compaction and leachate recirculation on anaerobic degradation of municipal solid waste (MSW) at different methane formation phases. Two stainless steel lysimeters, C1 and C2, were constructed by equipping a hydraulic cylinder to apply pressure load (42kPs) on the MSW. When MSW started to produce methane, C1 was compacted, but C2 was compacted when the methane production rate declined from the peak generation rate. Methane production of C1was inhibited by the compaction and resulted in producing a total of 106L methane (44L/kgVS). However, the compaction in C2 promoted MSW degradation resulting in producing a total of 298L methane (125L/kgVS). The concentrations of volatile fatty acids and chemical oxygen demand showed temporary increases, when pressure load was applied. It was considered that the increased substrate accessibility within MSW by compaction could cause either the inhibition or the enhancement of methane production, depending the tolerability of methanogens on the acidic inhibition. Leachate recirculation also gave positive effects on methane generation from wet waste in the decelerated methanogenic phase by increasing mass transfer and the concentrations of volatile fatty acids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modification of the acid/base properties of γ-Al2O3 by oxide additives: An ethanol TPD investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwak, Ja Hun; Lee, Jaekyoung; Szanyi, Janos

2016-02-26

The electronic properties of oxide-modified γ Al2O3 surfaces were investigated by using ethanol TPD. Ethanol TPD showed remarkable sensitivity toward the surface structures and electronic properties of the aluminas modified by various transition metal oxides. Maximum desorption rates for the primary product of ethanol adsorption, ethylene, were observed at 225 °C on non-modified γ-Al2O3. Desorption temperature of ethanol over a γ Al2O3 samples with different amounts of BaO linearly increased with increasing loading. On the contrary, ethanol desorption temperature on Pt modified γ-Al2O3 after calcined at 500 oC linearly decreased with increasing Pt loading. These results clearly suggested that themore » acid/base properties of the γ-Al2O3 surface can be strongly affected by ad-atoms. For confirming these arguments, we performed ethanol TPD experiments on various oxide modified γ-Al2O3 and normalized the maximum desorption temperatures based on the same number of oxide dopants. These normalized ethanol desorption temperatures linearly correlate with the electronegativity of the metal atom in the oxide. This linear relationship clearly demonstrates that the acidic properties of alumina surfaces can be systematically changed by ad-atoms.« less

Density and viscosity of some partially carbonated aqueous alkanolamine solutions and their blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiland, R.H.; Dingman, J.C.; Cronin, D.B.

1998-05-01

Very little information is available concerning the effect of acid gas loading on the physical properties of amine-treating solutions flowing through the absorption and regeneration columns used in gas processing. The densities and viscosities of partially carbonated monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) solutions were measured at 298 K. With increasing carbon dioxide loadings, significant increases in both density and viscosity were observed. These results were combined with literature data to produce correlations for alkanolamine solution density and viscosity as a function of amine concentration, carbon dioxide loading, and temperature. The resulting single-amine correlations were used to predict themore » densities and viscosities of DEA + MDEA and MEA + MDEA blends. Predictions are compared with data measured for these blends.« less

Chemicals and energy co-generation from direct hydrocarbons/oxygen proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Li, W. S.; Lu, D. S.; Luo, J. L.; Chuang, K. T.

A proton exchange membrane fuel cell for chemicals and energy co-generation was set up with hydrocarbons ethane, propane and butane as fuels, and the electrochemical performance of the cell was studied by using linear potential sweep, alternating current impedance and gas chromatography. The cell performance can be improved to a great extent by increasing the platinum load in the catalyst, by treating the membrane with phosphoric acid and by elevating temperature. The improvement of cell performance by the increase of platinum load is ascribed to the increase of reaction sites for hydrocarbon oxidation, that by phosphoric acid treatment to the increase of proton conductivity in Nafion membrane, and that by elevating temperature to the improvement in thermodynamic as well as kinetic aspects. Only a small fraction of the hydrocarbon is converted to carbon dioxide in this cell during its power generation. The current efficiency is 5% for the conversion of ethane to carbon dioxide in the ethane/oxygen fuel cell with 20% carbon-supported platinum as catalyst and phosphoric acid-treated membrane as proton exchange membrane at 0.2 V, 80 °C and ambient pressure. The reaction activity of hydrocarbons at the anode is in the order of propane, butane and ethane. The possible chemicals produced from the cell were hydrocarbons with more than six carbons, which are inactive at the anode under cell conditions.

Metal loading assessment of a small mountainous sub-basin characterized by acid drainage -- Prospect Gulch, upper Animas River watershed, Colorado

USGS Publications Warehouse

Wirt, Laurie; Leib, Kenneth J.; Melick, Roger; Bove, Dana J.

2001-01-01

strongly affected by natural acidity from pyrite weathering. Metal content in the water column is a composite of multiple sources affected by hydrologic, geologic, climatic, and anthropogenic conditions. Identifying sources of metals from various drainage areas was determined using a tracer injection approach and synoptic sampling during low flow conditions on September 29, 1999 to determine loads. The tracer data was interpreted in conjunction with detailed geologic mapping, topographic profiling, geochemical characterization, and the occurrence and distribution of trace metals to identify sources of ground-water inflows. For this highly mineralized sub-basin, we demonstrate that SO4, Al, and Fe load contributions from drainage areas that have experienced historical mining?although substantial?are relatively insignificant in comparison with SO4, Al, and Fe loads from areas experiencing natural weathering of highlyaltered, pyritic rocks. Regional weathering of acid-sulfate mineral assemblages produces moderately low pH waters elevated in SO4, Al, and Fe; but generally lacking in Cu, Cd, Ni, and Pb. Samples impacted by mining are also characterized by low pH and large concentrations of SO4, Al, and Fe; but contained elevated dissolved metals from ore-bearing vein minerals such as Cu, Zn, Cd, Ni, and Pb. Occurrences of dissolved trace metals were helpful in identifying ground-water sources and flow paths. For example, cadmium was greatest in inflows associated with drainage from inactive mine sites and absent in inflows that were unaffected by past mining activities and thus served as an important indicator of mining contamination for this environmental setting. The most heavily mine-impacted reach (PG153 to PG800), contributed 8% of the discharge, and 11%, 9%, and 12% of the total SO4, Al, and Fe loads in Prospect Gulch. The same reach yielded 59% and 37% of the total Cu and Zn loads for the subbasin. In contrast, the naturally acidic inflows from the Red Chemotroph iron spring yielded 39% of the discharge and 54%, 73%, and 87% of the SO4, Al, and Fe loads; but only 4% of the total Cu and 30% of the total Zn loads in Prospect Gulch. Base flow from the Prospect Gulch sub-basin contributes about 4.8 percent of the total discharge at the mouth of Cement Creek; compared with sampled instream loads of 1.8%, 8.8%, 15.9%, 28%, and 8.6% for SO4, Al, Fe, Cu and Zn, respectively. Water-shed scale remediation efforts targeted at reducing loads of SO4, Al, and Fe at inactive mine sites are likely to fail because the major sources of these constituents in Prospect Gulch are predominantly discharged from natural sources. Remediation goals aimed at reducing acidity and loads of Cu and other base metals, may succeed, however, because changes in pH and loads are disproportionately greater than increases in discharge over the same reach, and a substantial fraction of the metal loading is from mining-impacted reaches. Whether remediation of abandoned mines in Prospect Gulch can be successful depends on how goals are defined?that is, whether the objective is to reduce loads of SO4, Al, and Fe; or whether loads of Cu and other base metals and pH are targeted.

In vitro evaluation of α-lipoic acid-loaded lipid nanocapsules for topical delivery.

PubMed

Xia, Nan; Liu, Tian; Wang, Qiang; Xia, Qiang; Bian, Xiaoli

2017-09-01

This study aimed at in vitro evaluation of α-lipoic acid-loaded lipid nanocapsules for topical delivery, which was prepared by hot high-pressure homogenisation. Stable particles could be formed and particle size was 148.54 ± 2.31 nm with polydispersity index below 0.15. Encapsulation efficiency and drug loading of α-lipoic acid were 95.23 ± 0.45% and 2.81 ± 0.37%. Antioxidant study showed α-lipoic acid could be protected by lipid nanocapsules without loss of antioxidant activity. Sustained release of α-lipoic acid from lipid nanocapsules was obtained and cumulative release was 62.18 ± 1.51%. In vitro percutaneous study showed the amount of α-lipoic acid distributed in skin was 1.7-fold than permeated. Cytotoxicity assay and antioxidant activity on L929 cells indicated this formulation had low cytotoxicity and ability of protecting cells from oxidative damage within specific concentration. These studies suggested α-lipoic acid-loaded lipid nanocapsules could be potential formulation for topical delivery.

Fabricating core (Au)-shell (different stimuli-responsive polymers) nanoparticles via inverse emulsion polymerization: Comparing DOX release behavior in dark room and under NIR lighting.

PubMed

Mazloomi-Rezvani, Mahsa; Salami-Kalajahi, Mehdi; Roghani-Mamaqani, Hossein

2018-06-01

Different core-shell nanoparticles with Au as core and stimuli-responsive polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(N-isopropylacrylamide) (PNIPAAm), poly(N,N'-methylenebis(acrylamide)) (PMBA), poly(2-hydroxyethyl methacrylate) (PHEMA) and poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) as shells were fabricated via inverse emulsion polymerization. Dynamic light scattering (DLS) was used to investigate particles sizes and particle size distributions and transmission electron microscopy (TEM) was applied to observe the core-shell structure of Au-polymer nanoparticles. Also, surface charge of all samples was studied by measurement of zeta potentials. Synthesized core-shell nanoparticles were utilized as nanocarriers of DOX as anti-cancer drug and drug release behaviors were investigated in dark room and under irradiation of near-infrared (NIR) light. Results showed that all core-shell samples have particle sizes less than 100 nm with narrow particle size distributions. Moreover, amount of drug loading decreased by increasing zeta potential. In dark room, lower pH resulted in higher cumulative drug release due to better solubility of DOX in acidic media. Also, NIR lighting on DOX-loaded samples led to increasing cumulative drug release significantly. However, DOX-loaded Au-PAA and Au-PMAA showed higher drug release at pH = 7.4 compared to 5.3 under NIR lighting. Copyright © 2018 Elsevier B.V. All rights reserved.

Curcumin delivery from poly(acrylic acid-co-methyl methacrylate) hollow microparticles prevents dopamine-induced toxicity in rat brain synaptosomes.

PubMed

Yoncheva, Krassimira; Kondeva-Burdina, Magdalena; Tzankova, Virginia; Petrov, Petar; Laouani, Mohamed; Halacheva, Silvia S

2015-01-01

The potential of poly(methyl methacrylate-co-acrylic acid) (PMMA-AA) copolymers to form hollow particles and their further formulation as curcumin delivery system have been explored. The particles were functionalized by crosslinking the acrylic acid groups via bis-amide formation with either cystamine (CYS) or 3,3'-dithiodipropionic acid dihydrazide (DTP) which simultaneously incorporated reversibility due to the presence of disulfide bonds within the crosslinker. Optical micrographs showed the formation of spherical hollow microparticles with a size ranging from 1 to 7 μm. Curcumin was loaded by incubation of its ethanol solution with aqueous dispersions of the cross-linked particles and subsequent evaporation of the ethanol. Higher loading was observed in the microparticles with higher content of hydrophobic PMMA units indicating its influence upon the loading of hydrophobic molecules such as curcumin. The in vitro release studies in a phosphate buffer showed no initial burst effect and sustained release of curcumin that correlated with the swelling of the particles under these conditions. The capacity of encapsulated and free curcumin to protect rat brain synaptosomes against dopamine-induced neurotoxicity was examined. The encapsulated curcumin showed greater protective effects in rat brain synaptosomes as measured by synaptosomal viability and increased intracellular levels of glutathione. Copyright © 2015 Elsevier B.V. All rights reserved.

Injectable gentamicin-loaded thermo-responsive hyaluronic acid derivative prevents infection in a rabbit model.

PubMed

Ter Boo, Gert-Jan A; Arens, Daniel; Metsemakers, Willem-Jan; Zeiter, Stephan; Richards, R Geoff; Grijpma, Dirk W; Eglin, David; Moriarty, T Fintan

2016-10-01

Despite the use of systemic antibiotic prophylaxis, the surgical fixation of open fractures with osteosynthesis implants is associated with high infection rates. Antibiotic-loaded biomaterials (ALBs) are increasingly used in implant surgeries across medical specialties to deliver high concentrations of antibiotics to the surgical site and reduce the risk of implant-associated infection. ALBs which are either less or not restricted in terms of spatial distribution and which may be applied throughout complex wounds could offer improved protection against infection in open fracture care. A thermo-responsive hyaluronic acid derivative (hyaluronic acid-poly(N-isopropylacrylamide) (HApN)) was prepared by a direct amidation reaction between the tetrabutyl ammonium (TBA) salt of hyaluronic acid and amine-terminated poly(N-isopropylacrylamide) (pN). The degree of grafting, and gelation properties of this gel were characterized, and the composition was loaded with gentamicin. The rheological- and release properties of this gentamicin-loaded HApN composition were tested in vitro and its efficacy in preventing infection was tested in a rabbit model of osteosynthesis contaminated with Staphylococcus aureus. The gentamicin-loaded HApN composition was able to prevent bacterial colonization of the implant site as shown by quantitative bacteriology. This finding was supported by histopathological evaluation of the humeri samples where no bacteria were found in the stained sections. In conclusion, this gentamicin-loaded HApN hydrogel effectively prevents infection in a complex wound, simulating a contaminated fracture treated with plating osteosynthesis. Fracture fixation after trauma is associated with high infection rates. Antibiotic loaded biomaterials (ALBs) can provide high local concentrations without systemic side effects. However, the currently available ALBs have limited accessibility to contaminated tissues in open fractures because of predetermined shape. Thus, a novel thermo-responsive hyaluronan based hydrogel with control over gelation temperature is reported. The efficacy of this gentamicin loaded hyaluronan derivative is demonstrated in an in vivo fracture model in the presence of fracture fixation hardware. The bacterial burden is cleared in all of the inoculated rabbits in the presence of the ALB. Thus, the proposed injectable thermo-responsive hyaluronan presents an effective ALB for the prevention of infection. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of the SiO 2 support on the catalytic performance of Ag/ZrO 2/SiO 2 catalysts for the single-bed production of butadiene from ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagle, Vanessa Lebarbier; Flake, Matthew D.; Lemmon, Teresa L.

A ternary Ag/ZrO 2/SiO 2 catalyst system was studied for single-step conversion of ethanol to butadiene by varying the catalyst composition (Ag, Ir, or Pt metal component, Ag/ZrO 2 loading, and choice of SiO 2 support) and operating conditions (space velocity and feed gas composition). Exceptional catalytic performance was achieved over a 1%Ag/4%ZrO 2/SiO 2-SBA-16 catalyst leading to 99% conversion and 71% butadiene selectivity while operating under mild conditions (325°C, 1 atm, and 0.23 h –1). Several classes of silica—silica gels, fumed silicas, mesoporous silicas)—were evaluated as catalyst supports, and SBA-16 was found to be the most promising choice. Themore » SiO 2 support was found to significantly influence both conversion and selectivity. A higher SiO 2 catalyst surface area facilitates increased Ag dispersion which leads to greater conversion due to the accelerated initial ethanol dehydrogenation reaction step. By independently varying Ag and ZrO 2 loading, Ag was found to be the main component that affects ethanol conversion. ZrO 2 loading and thus Lewis acid sites concentration was found to have little impact on the ethanol conversion. Butadiene selectivity depends on the concentration of Lewis acid site, which in turn differs depending on the choice of SiO 2 support material. We observed a direct relationship between butadiene selectivity and concentration of Lewis acid sites. Butadiene selectivity decreases as the concentration of Lewis acid sites increases, which corresponds to an increase in ethanol dehydration to ethylene and diethyl ether. Additionally, adding H 2 to the feed had little effect on conversion while improving catalytic stability; however, selectivity to butadiene decreased. Lastly, catalyst regenerability was successfully demonstrated for several cycles.« less

Effect of the SiO 2 support on the catalytic performance of Ag/ZrO 2/SiO 2 catalysts for the single-bed production of butadiene from ethanol

DOE PAGES

Dagle, Vanessa Lebarbier; Flake, Matthew D.; Lemmon, Teresa L.; ...

2018-05-19

A ternary Ag/ZrO 2/SiO 2 catalyst system was studied for single-step conversion of ethanol to butadiene by varying the catalyst composition (Ag, Ir, or Pt metal component, Ag/ZrO 2 loading, and choice of SiO 2 support) and operating conditions (space velocity and feed gas composition). Exceptional catalytic performance was achieved over a 1%Ag/4%ZrO 2/SiO 2-SBA-16 catalyst leading to 99% conversion and 71% butadiene selectivity while operating under mild conditions (325°C, 1 atm, and 0.23 h –1). Several classes of silica—silica gels, fumed silicas, mesoporous silicas)—were evaluated as catalyst supports, and SBA-16 was found to be the most promising choice. Themore » SiO 2 support was found to significantly influence both conversion and selectivity. A higher SiO 2 catalyst surface area facilitates increased Ag dispersion which leads to greater conversion due to the accelerated initial ethanol dehydrogenation reaction step. By independently varying Ag and ZrO 2 loading, Ag was found to be the main component that affects ethanol conversion. ZrO 2 loading and thus Lewis acid sites concentration was found to have little impact on the ethanol conversion. Butadiene selectivity depends on the concentration of Lewis acid site, which in turn differs depending on the choice of SiO 2 support material. We observed a direct relationship between butadiene selectivity and concentration of Lewis acid sites. Butadiene selectivity decreases as the concentration of Lewis acid sites increases, which corresponds to an increase in ethanol dehydration to ethylene and diethyl ether. Additionally, adding H 2 to the feed had little effect on conversion while improving catalytic stability; however, selectivity to butadiene decreased. Lastly, catalyst regenerability was successfully demonstrated for several cycles.« less

Liposome-based mucus-penetrating particles (MPP) for mucosal theranostics: demonstration of diamagnetic chemical exchange saturation transfer (diaCEST) magnetic resonance imaging (MRI).

PubMed

Yu, Tao; Chan, Kannie W Y; Anonuevo, Abraham; Song, Xiaolei; Schuster, Benjamin S; Chattopadhyay, Sumon; Xu, Qingguo; Oskolkov, Nikita; Patel, Himatkumar; Ensign, Laura M; van Zjil, Peter C M; McMahon, Michael T; Hanes, Justin

2015-02-01

Mucus barriers lining mucosal epithelia reduce the effectiveness of nanocarrier-based mucosal drug delivery and imaging ("theranostics"). Here, we describe liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, e.g., the diaCEST MRI contrast agent barbituric acid (BA). We observed that polyethylene glycol (PEG)-coated liposomes containing ≥7 mol% PEG diffused only ~10-fold slower in human cervicovaginal mucus (CVM) compared to their theoretical speeds in water. 7 mol%-PEG liposomes contained sufficient BA loading for diaCEST contrast, and provided improved vaginal distribution compared to 0 and 3mol%-PEG liposomes. However, increasing PEG content to ~12 mol% compromised BA loading and vaginal distribution, suggesting that PEG content must be optimized to maintain drug loading and stability. Non-invasive diaCEST MRI illustrated uniform vaginal coverage and longer retention of BA-loaded 7 mol%-PEG liposomes compared to unencapsulated BA. Liposomal MPP with optimized PEG content hold promise for drug delivery and imaging at mucosal surfaces. This team of authors characterized liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, such as barbituric acid (a diaCEST MRI contrast agent) and concluded that liposomal MPP with optimized PEG coating enables drug delivery and imaging at mucosal surfaces. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of in vitro chewing and bruxism events on remineralization, at the resin-dentin interface.

PubMed

Toledano, Manuel; Cabello, Inmaculada; Aguilera, Fátima S; Osorio, Estrella; Osorio, Raquel

2015-01-02

The purpose of this study was to evaluate if different in vitro functional and parafunctional habits promote mineralization at the resin-dentin interface after bonding with three different adhesive approaches. Dentin surfaces were subjected to distinct treatments: demineralization by (1) 37% phosphoric acid (PA) followed by application of an etch-and-rinse dentin adhesive, Single Bond (SB) (PA+SB); (2) 0.5 M ethylenediaminetetraacetic acid (EDTA) followed by SB (EDTA+SB); (3) application of a self-etch dentin adhesive, Clearfil SE Bond (SEB). Different loading waveforms were applied: No cycling (I), cycled in sine (II) or square (III) waves, sustained loading hold for 24 h (IV) or sustained loading hold for 72 h (V). Remineralization at the bonded interfaces was assessed by AFM imaging/nano-indentation, Raman spectroscopy and Masson's trichrome staining. In general, in vitro chewing and parafunctional habits, promoted an increase of nano-mechanical properties at the resin-dentin interface. Raman spectroscopy through cluster analysis demonstrated an augmentation of the mineral-matrix ratio in loaded specimens. Trichrome staining reflected a narrow demineralized dentin matrix after loading in all groups except in PA+SB and EDTA+SB samples after sustained loading hold for 72 h, which exhibited a strong degree of mineralization. In vitro mechanical loading, produced during chewing and bruxism (square or hold 24 and 72 h waveforms), induced remineralization at the resin-dentin bonded interface. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dynamic compressive loading enhances cartilage matrix synthesis and distribution and suppresses hypertrophy in hMSC-laden hyaluronic acid hydrogels.

PubMed

Bian, Liming; Zhai, David Y; Zhang, Emily C; Mauck, Robert L; Burdick, Jason A

2012-04-01

Mesenchymal stem cells (MSCs) are being recognized as a viable cell source for cartilage repair, and there is growing evidence that mechanical signals play a critical role in the regulation of stem cell chondrogenesis and in cartilage development. In this study we investigated the effect of dynamic compressive loading on chondrogenesis, the production and distribution of cartilage specific matrix, and the hypertrophic differentiation of human MSCs encapsulated in hyaluronic acid (HA) hydrogels during long term culture. After 70 days of culture, dynamic compressive loading increased the mechanical properties, as well as the glycosaminoglycan (GAG) and collagen contents of HA hydrogel constructs in a seeding density dependent manner. The impact of loading on HA hydrogel construct properties was delayed when applied to lower density (20 million MSCs/ml) compared to higher seeding density (60 million MSCs/ml) constructs. Furthermore, loading promoted a more uniform spatial distribution of cartilage matrix in HA hydrogels with both seeding densities, leading to significantly improved mechanical properties as compared to free swelling constructs. Using a previously developed in vitro hypertrophy model, dynamic compressive loading was also shown to significantly reduce the expression of hypertrophic markers by human MSCs and to suppress the degree of calcification in MSC-seeded HA hydrogels. Findings from this study highlight the importance of mechanical loading in stem cell based therapy for cartilage repair in improving neocartilage properties and in potentially maintaining the cartilage phenotype.

Reductive dehalogenation of haloacetic acids by hemoglobin-loaded carbon nanotube electrode.

PubMed

Li, Yu-Ping; Cao, Hong-Bin; Zhang, Yi

2007-01-01

Hemoglobin (Hb) was immobilized on carbon nanotube (CNT) electrode to catalyze the dehalogenation of haloacetic acids (HAAs). FTIR and UV measurements were performed to investigate the activity-keep of Hb after immobilization on CNT. The electrocatalytic behaviors of the Hb-loaded electrode for the dehalogenation of HAAs were studied by cyclic voltammmetry and constant-potential electrolysis technique. An Hb-loaded packed-bed flow reactor was also constructed for bioelectrocatalytic dehalogenation of HAAs. The results showed that Hb retained its nature, the essential features of its native secondary structure, and its biocatalytic activity after immobilization on CNT. Chloroacetic acids and bromoacetic acids could be dehalogenated completely with Hb catalysis through a stepwise dehalogenation process at -0.400V (vs. saturated calomel electrode (SCE)) and -0.200V (vs. SCE), respectively. The removal of 10.5mM trichloroacetic acid and dichloroacetic acid is ca. 97% and 63%, respectively, with electrolysis for 300min at -0.400V (vs. SCE) using the Hb-loaded packed-bed flow reactor, and almost 100% of tribromoacetic acid and dibromoacetic acid was removed with electrolysis for 40min at -0.200V (vs. SCE). The average current efficiency of Hb-catalytic dehalogenation almost reaches 100%.

Friction and Wear of Iron in Corrosive Media

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1982-01-01

Friction and wear experiments were conducted with elemental iron exposed to various corrosive media including two acids, base, and a salt. Studies involved various concentrations of nitric and sulfuric acids, sodium hydroxide, and sodium chloride. Load and reciprocating sliding speed were kept constant. With the base NaOH an increase in normality beyond 0.01 N resulted in a decrease in both friction and wear. X-ray photoelectron spectroscopy (XPS) analysis of the surface showed a decreasing concentration of ferric oxide (Fe2O3) on the iron surface with increasing NaOH concentration. With nitric acid (HNO3) friction decreased in solutions to 0.05 N, beyond which no further change in friction was observed. The concentration of Fe2O3 on the surface continued to increase with increasing normality. XPS analysis revealed the presence of sulfates in addition of Fe2O3 on surfaces exposed to sulfuric acid and iron chlorides but no sodium on surfaces exposed to NaCl.

l-Tyrosine-loaded nanoparticles increase the antitumoral activity of direct electric current in a metastatic melanoma cell model

PubMed Central

de Campos, Vânia Emerich Bucco; Teixeira, Cesar Augusto Antunes; da Veiga, Venicio Feo; Júnior, Eduardo Ricci; Holandino, Carla

2010-01-01

Inhibition of tumor growth induced by treatment with direct electric current (DC) has been reported in several models. One of the mechanisms responsible for the antitumoral activity of DC is the generation of oxidative species, known as chloramines. With the aim of increasing chloramine production in the electrolytic medium and optimizing the antitumoral effects of DC, poly(ɛ-caprolactone) (PCL) nanoparticles (NPs) loaded with the amino acid tyrosine were obtained. The physical–chemical characterization showed that the NPs presented size in nanometric range and monomodal distribution. A slightly negative electrokinetic potential was also found in both blank NPs and l-tyrosine-loaded PCL NPs. The yield of the loading process was approximately 50%. Within 3 h of dissolution assay, a burst release of about 80% l-tyrosine was obtained. The in vitro cytotoxicity of DC was significantly increased when associated with l-tyrosine-loaded NPs, using a murine multidrug-resistant melanoma cell line model. This study showed that the use of the combination of nanotechnology and DC has a promising antineoplastic potential and opens a new perspective in cancer therapy. PMID:21187948

Formulation and characterization of poly(ethylene glycol)-based, 5-aminolevulinic acid-loaded solid-dosage forms intended for photodynamic and photodiagnostic methodologies in the colorectal region.

PubMed

McCarron, Paul A; Andrews, Gavin P; Morrow, Desmond I J; Woolfson, A David; Donnelly, Ryan F

2007-01-01

Aminolevulinic acid-loaded, poly(ethylene glycol) disks prepared using three molecular weights (1000, 6000, and 10,000) were shown to be of potential for rectal administration as part of photodynamic and photodiagnostic colorectal procedures. The disk-shaped delivery system was mechanically robust, as judged by friability measurements. Calorimetric analysis confirmed that low concentrations of ALA (1% w/w) were dispersed completely throughout the PEG matrix, but higher concentrations (5% w/w and 10% w/w) formed crystalline suspensions. The molecular weight of the PEG determined the melting temperature, with PEG 1000 being suitable for melting around body temperature. The drug release kinetics were shown to be a function of both molecular weight and drug loading. Although the higher molecular weight PEG disks were resistant to surface erosion arising from an aqueous receptor phase, this effect was counterbalanced by more rapid and complete release when the ALA loading was increased. The lowest loading used (1% w/w) produced incomplete release, often not exceeding 30% of the total amount of drug. Results suggest that this simple formulation containing ALA can be administered directly to the colorectal area and is a feasible alternative to peroral dosing of ALA.

Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid

NASA Astrophysics Data System (ADS)

Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng

2014-03-01

MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H2O2 indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions.

Budesonide treatment is associated with increased bile acid absorption in collagenous colitis.

PubMed

Bajor, A; Kilander, A; Gälman, C; Rudling, M; Ung, K-A

2006-12-01

Bile acid malabsorption is frequent in collagenous colitis and harmful bile acids may play a pathophysiological role. Glucocorticoids increase ileal bile acid transport. Budesonide have its main effect in the terminal ileum. To evaluate whether the symptomatic effect of budesonide is linked to increased uptake of bile acids. Patients with collagenous colitis were treated with budesonide 9 mg daily for 12 weeks. Prior to and after 8 weeks of treatment, the (75)SeHCAT test, an indirect test for the active uptake of bile acid-s, measurements of serum 7alpha-hydroxy-4-cholesten-3-one, an indicator of hepatic bile acid synthesis, and registration of symptoms were performed. The median (75)SeHCAT retention increased from 18% to 35% (P < 0.001, n = 25) approaching the values of healthy controls (38%). The 7alpha-hydroxy-4-cholesten-3-one values decreased significantly among those with initially high synthesis (from 36 to 23 ng/mL, P = 0.04, n = 9); however, for the whole group the values were not altered (19 ng/mL vs. 13 ng/mL, P = 0.23, N.S., n = 19). The normalization of the (75)SeHCAT test and the reduction of bile acid synthesis in patients with initially high synthetic rate, suggests that the effect of budesonide in collagenous colitis may be in part due to decreased bile acid load on the colon.

Biodegradation of a surrogate naphthenic acid under denitrifying conditions.

PubMed

Gunawan, Yetty; Nemati, Mehdi; Dalai, Ajay

2014-03-15

Extraction of bitumen from the shallow oil sands generates extremely large volumes of waters contaminated by naphthenic acid which pose severe environmental and ecological risks. Aerobic biodegradation of NA in properly designed bioreactors has been investigated in our earlier works. In the present work, anoxic biodegradation of trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA) coupled to denitrification was investigated as a potential ex situ approach for the treatment of oil sand process waters in bioreactors whereby excessive aeration cost could be eliminated, or as an in situ alternative for the treatment of these waters in anoxic stabilization ponds amended with nitrate. Using batch and continuous reactors (CSTR and biofilm), effects of NA concentration (100-750mgL(-1)), NA loading rate (up to 2607.9mgL(-1)h(-1)) and temperature (10-35°C) on biodegradation and denitrification processes were evaluated. In the batch system biodegradation of trans-4MCHCA coupled to denitrification occurred even at the highest concentration of 750mgL(-1). Consistent with the patterns reported for aerobic biodegradation, increase in initial concentration of NA led to higher biodegradation and denitrification rates and the optimum temperature was determined as 23-24°C. In the CSTR, NA removal and nitrate reduction rates passed through a maximum due to increases in NA loading rate. NA loading rate of 157.8mgL(-1)h(-1) at which maximum anoxic NA and nitrate removal rates (105.3mgL(-1)h(-1) and 144.5mgL(-1)h(-1), respectively) occurred was much higher than those reported for the aerobic alternative (NA loading and removal rates: 14.2 and 9.6mgL(-1)h(-1), respectively). In the anoxic biofilm reactor removal rates of NA and nitrate were dependent on NA loading rate in a linear fashion for the entire range of applied loading rates. The highest loading and removal rates for NA were 2607.9 and 2028.1mgL(-1)h(-1), respectively which were at least twofold higher than the values reported for the aerobic biofilm reactor. The highest nitrate removal rate coincided with maximum removal rate of NA and was 3164.7mgL(-1)h(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of emplaced nZVI mass and groundwater velocity on PCE dechlorination and hydrogen evolution in water-saturated sand.

PubMed

Kim, Hye-Jin; Leitch, Megan; Naknakorn, Bhanuphong; Tilton, Robert D; Lowry, Gregory V

2017-01-15

The effect of nZVI mass loading and groundwater velocity on the tetrachloroethylene (PCE) dechlorination rate and the hydrogen evolution rate for poly(maleic acid-co-olefin) (MW=12K) coated nZVI was examined. In batch reactors, the PCE reaction rate constant (3.7×10 -4 Lhr -1 m -2 ) and hydrogen evolution rate constant (1.4 nanomolLhr -1 m -2 ) were independent of nZVI concentration above 10g/L, but the PCE dechlorination rate decreased and the hydrogen evolution rate increased for nZVI concentration below 10g/L. The nonlinearity between nZVI mass loading and PCE dechlorination and H 2 evolution was explained by differences in pH and E h at each nZVI mass loading; PCE reactivity increased when solution E h decreased, and the H 2 evolution rate increased with decreasing pH. Thus, nZVI mass loading of <5g/L yields lower reactivity with PCE and lower efficiency of Fe° utilization than for higher nZVI mass loading. The PCE dechlorination rate increased with increasing pore-water velocity, suggesting that mass transfer limits the reaction at low porewater velocity. Overall, this work suggests that design of nZVI-based reactive barriers for groundwater treatment should consider the non-linear effects of both mass loading and flow velocity on performance and expected reactive lifetime. Copyright © 2016 Elsevier B.V. All rights reserved.

Retinoid receptors, transporters, and metabolizers as therapeutic targets in late onset Alzheimer disease.

PubMed

Goodman, Ann B

2006-12-01

Vitamin A (retinoid) is required in the adult brain to enable cognition, learning, and memory. While brain levels of retinoid diminish over the course of normal ageing, retinoid deficit is greater in late onset Alzheimer disease (LOAD) brains than in normal-aged controls. This paper reviews recent evidence supporting these statements and further suggests that genes necessary for the synthesis, transport and function of retinoid to and within the ageing brain are appropriate targets for treatment of LOAD. These genes tend to be clustered with genes that have been proposed as candidates in LOAD, are found at chromosomal regions linked to LOAD, and suggest the possibility of an overall coordinated regulation. This phenomenon is termed Chromeron and is analogous to the operon mechanism observed in prokaryotes. Suggested treatment targets are the retinoic-acid inactivating enzymes (CYP26)s, the retinol binding and transport proteins, retinol-binding protein (RBP)4 and transthyretin (TTR), and the retinoid receptors. TTR as a LOAD target is the subject of active investigation. The retinoid receptors and the retinoid-inactivating enzymes have previously been proposed as targets. This is the first report to suggest that RBP4 is an amenable treatment target in LOAD. RBP4 is elevated in type-2 diabetes and obesity, conditions associated with increased risk for LOAD. Fenretinide, a novel synthetic retinoic acid (RA) analog lowers RBP4 in glucose intolerant obese mice. The feasibility of using fenretinide either as an adjunct to present LOAD therapies, or on its own as an early prevention strategy should be determined. (c) 2006 Wiley-Liss, Inc.

Effects of diet on titratable acid-base excretion in grasshoppers.

PubMed

Frazier, M R; Harrison, J F; Behmer, S T

2000-01-01

Despite the potential for diet to affect organismal acid-base status, especially in herbivores, little is known about the effects of diet on acid-base loading and excretion. We tested the effects of diet on acid-base loading and excretion in grasshoppers by (a) comparing the fecal acid-base content of 15 grasshopper species collected from the field and (b) comparing fecal acid-base excretion rates of Schistocerca americana grasshoppers fed vegetable diets that differed in their ashed and raw acid-base contents. The field experiments indicated that grass-feeding species excrete fairly neutral fecal pellets, while forb/mixed-feeding species vary widely in their fecal acid-base contents. In the laboratory experiment, acid-base excretion rates were positively correlated with dietary ashed base intake rates but were not correlated with the acid-base content of raw, unashed diet or feeding rate. These experiments suggest that some diets could strongly challenge the acid-base homeostasis of herbivores; in some grasshoppers, dietary acid-base loads could produce certainly lethal 1-unit changes in average body pH within 6 h if they were not excreted.

11β Hydroxysteroid dehydrogenase type 2 and dietary acid load are independently associated with blood pressure in healthy children and adolescents.

PubMed

Krupp, Danika; Shi, Lijie; Maser-Gluth, Christiane; Pietzarka, Marion; Remer, Thomas

2013-03-01

The reduced activity of 11β hydroxysteroid dehydrogenase type 2 (11βHSD2) contributes to elevated blood pressure (BP) in clinical syndromes, but its effect on BP in the physiologic range is unclear. We examined the association of 11βHSD2 activity with BP in healthy children independent of known BP-related dietary and other factors and determined whether the diet-dependent acid load may constitute a dietary factor related to BP. We conducted a cross-sectional analysis in 267 healthy children (age range: 4-14 y) who provided a 24-h urine sample, a parallel 3-d weighed dietary record, and 1-3 BP measurements ±1.5 y around the urine collection. The ratio of urinary free cortisone to cortisol measured by using a radioimmunoassay was used as an index for 11βHSD2. Urinary net acid excretion and the urinary and dietary potential renal acid load (PRAL) were used to predict the diet-dependent acid load. The PRAL was calculated as the sum of major mineral nonbicarbonate anions minus the sum of mineral cations. Sex-, age- and height-independent SD scores (SDSs) of systolic and diastolic BP were used as outcomes in linear regression analyses. 11βHSD2 was inversely associated with systolic BP SDSs in basic models and in analyses adjusted for body size, maternal BP, breastfeeding, and dietary intakes of total energy, salt, and fruit and vegetables (P = 0.03). In models that included indexes of dietary acid load instead of fruit and vegetables, all 3 acid-load biomarkers were significantly (P = 0.006-0.02) directly related to systolic BP. A lower 11βHSD2 activity and higher dietary acid load may independently contribute to higher systolic BP in healthy children.

Interaction of sulfuric acid corrosion and mechanical wear of iron

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1986-01-01

Friction and wear experiment were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

Interaction of sulfuric acid corrosion and mechanical wear of iron

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1984-01-01

Friction and wear experiments were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

Water-quality effects on Baker Lake of recent volcanic activity at Mount Baker, Washington

USGS Publications Warehouse

Bortleson, Gilbert Carl; Wilson, Reed T.; Foxworthy, B.L.

1976-01-01

Increased volcanic activity on Mount Baker, which began in March 1975, represents the greatest known activity of a Cascade Range volcano since eruptions at Lassen Peak, Calif. during 1914-17. Emissions of dust and increased emanations of steam, other gases, and heat from the Sherman Crater area of the mountain focused attention on the possibility of hazardous events, including lava flows, pyroclastic eruptions, avalanches, and mudflows. However, the greatest undesirable natural results that have been observed after one year of the increased activity are an increase in local atmospheric pollution and a decrease in the quality of some local water resources, including Baker Lake. Baker Lake, a hydropower reservoir behind Upper Baker Dam, supports a valuable fishery resource and also is used for recreation. The lake's feedwater is from Baker River and many smaller streams, some of which, like Boulder Creek, drain parts of Mount Baker. Boulder Creek receives water from Sherman Crater, and its channel is a likely route for avalanches or mudflows that might originate in the crater area. Boulder Creek drains only about 5 percent of the total drainage area of Baker Lake, but during 1975 carried sizeable but variable loads of acid and dissolved minerals into the lake. Sulfurous gases and the fumarole dust from Sherman Crater are the main sources for these materials, which are brought into upper Boulder Creek by meltwater from the crater. In September 1973, before the increased volcanic activity, Boulder Creek near the lake had a pH of 6.0-6.6; after the increase the pH ranged as low as about 3.5. Most nearby streams had pH values near 7. On April 29, in Boulder Creek the dissolved sulfate concentration was 6 to 29 times greater than in nearby creeks or in Baker River; total iron was 18-53 times greater than in nearby creeks; and other major dissolved constituents generally 2 to 7 times greater than in the other streams. The short-term effects on Baker Lake of the acidic, mineral-rich inflow depend mainly on: (1) the rate of flow and the character of Boulder Creek water at the time; (2) the relative rate of inflow of the feedwater from other streams; and (3) whether the reservoir is temperature-stratified (summer) or homothermal (winter). A distinct layer of Boulder Creek water was found in the lake in September 1975 extending at least 0.3 miles (.5 km) downreservoir. The greatest opportunity for water from Boulder Creek to persist as a layer and extend farthest before mixing with the other reservoir water is when Baker Lake is strongly stratified and Boulder Creek flow rate is large in relation to other feedwater. Baker Lake probably could assimilate indefinitely the acid loads measured during 1975, by dilution, chemical neutralization, and buffering of the acid-rich Boulder creek water. Minor elements found in Boulder Creek water included arsenic, selenium, and mercury; however, none of these would reach the limits recommended by the U.S. Environmental Protection Agency for public water supplies unless their concentrations increased to several times the amounts found during this study. Under the prevailing conditions, acid-rich Boulder Creek water apparently cannot accumulate as a pool, or persist as a layer long enough to reach Upper Baker Dam and attack the concrete. However, even if the acid load from Boulder Creek does not greatly increase, occasional light fish mortalities may result near the mouth of the creek. Greater acid and mineral loads, resulting from further increases in volcanic activity or other possible causes, could be more harmful, especially to the fish. Continued monitoring of Boulder Creek flow and water quality is needed to rapidly any changes in conditions at Sherman Crater, and to provide warning of possible greater impacts on Baker Lake from any future increases in Mount Baker activity.

Performance assessment of two-stage anaerobic digestion of kitchen wastes.

PubMed

Bo, Zhang; Pin-Jing, He

2014-01-01

This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

Impaired acid neutralization in the duodenum in pancreatic insufficiency.

PubMed

Dutta, S K; Russell, R M; Iber, F L

1979-10-01

The influence of severe exocrine pancreatic disease on the acid-neutralizing capacity of the duodenum was studied in five patients with pancreatic insufficiency (PI) and six control subjects using duodenal perfusion-marker technique. Hydrochloric acid (0.1 N containing 1% PEG) was infused at constant rates (1.2, 4.5 and 7.0 ml/min) into the duodenum just distal to the duodenal bulb. Samples were aspirated from the tip of the duodenal perfusion tube located at the ligament of Treitz. All samples were analyzed for volume, pH, titrable acidity, PEG and [14C]PEG (gastric marker) determination. Patients with PI demonstrated significantly diminished ability to neutralize various acid loads as compared to controls who virtually completely neutralized acid loads in the range of maximal gastric acid secretion. Exogenous secretin did not significantly improve percent acid neutralized in PI. These data clearly indicate that patients with PI have significantly impaired ability to neutralize even small loads of acid in the duodenum.

Elimination of mouse tumor cells from neonate spermatogonial cells utilizing cisplatin-entrapped folic acid-conjugated poly(lactic-co-glycolic acid) nanoparticles in vitro.

PubMed

Shabani, Ronak; Ashjari, Mohsen; Ashtari, Khadijeh; Izadyar, Fariborz; Behnam, Babak; Khoei, Samideh; Asghari-Jafarabadi, Mohamad; Koruji, Morteza

2018-01-01

Some male survivors of childhood cancer are suffering from azoospermia. In addition, spermatogonial stem cells (SSCs) are necessary for the improvement of spermatogenesis subsequent to exposure to cytotoxic agents such as cisplatin. The aim of this study was to evaluate the anticancer activity of cisplatin-loaded folic acid-conjugated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on mouse malignant cell line (EL4) and SSCs in vitro. SSCs were co-cultured with mouse malignant cell line (EL4) cells and divided into four culture groups: 1) control (cells were co-cultured in the culture medium), 2) co-cultured cells were treated with cisplatin (10 μg/mL), 3) co-cultured cells were treated with cisplatin-loaded folic acid-conjugated PLGA NPs, and 4) co-cultures were treated with folic acid-conjugated PLGA for 48 hours. The NPs were prepared, characterized, and targeted with folate. In vitro release characteristics, loading efficiency, and scanning electron microscopy and transmission electron microscopy images were studied. Cancer cells were assayed after treatment using flow cytometry and TUNEL assay. The co-cultures of SSCs and EL4 cells were injected into seminiferous tubules of the testes after treating with cis-diaminedichloroplatinum/PLGA NPs. The mean diameter of PLGA NPs ranged between 150 and 250 nm. The number of TUNEL-positive cells increased, and the expression of Bax and caspase-3 were upregulated in EL4 cells in Group 4 compared with Group 2. There was no pathological tumor in testes after transplantation with treated co-cultured cells. The PLGA NPs appeared to act as a promising carrier for cisplatin administration, which was consistent with a higher activation of apoptosis than free drug.

Elimination of mouse tumor cells from neonate spermatogonial cells utilizing cisplatin-entrapped folic acid-conjugated poly(lactic-co-glycolic acid) nanoparticles in vitro

PubMed Central

Shabani, Ronak; Ashjari, Mohsen; Ashtari, Khadijeh; Izadyar, Fariborz; Behnam, Babak; Khoei, Samideh; Asghari-Jafarabadi, Mohamad; Koruji, Morteza

2018-01-01

Background Some male survivors of childhood cancer are suffering from azoospermia. In addition, spermatogonial stem cells (SSCs) are necessary for the improvement of spermatogenesis subsequent to exposure to cytotoxic agents such as cisplatin. Objective The aim of this study was to evaluate the anticancer activity of cisplatin-loaded folic acid-conjugated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on mouse malignant cell line (EL4) and SSCs in vitro. Methods SSCs were co-cultured with mouse malignant cell line (EL4) cells and divided into four culture groups: 1) control (cells were co-cultured in the culture medium), 2) co-cultured cells were treated with cisplatin (10 μg/mL), 3) co-cultured cells were treated with cisplatin-loaded folic acid-conjugated PLGA NPs, and 4) co-cultures were treated with folic acid-conjugated PLGA for 48 hours. The NPs were prepared, characterized, and targeted with folate. In vitro release characteristics, loading efficiency, and scanning electron microscopy and transmission electron microscopy images were studied. Cancer cells were assayed after treatment using flow cytometry and TUNEL assay. The co-cultures of SSCs and EL4 cells were injected into seminiferous tubules of the testes after treating with cis-diaminedichloroplatinum/PLGA NPs. Results The mean diameter of PLGA NPs ranged between 150 and 250 nm. The number of TUNEL-positive cells increased, and the expression of Bax and caspase-3 were upregulated in EL4 cells in Group 4 compared with Group 2. There was no pathological tumor in testes after transplantation with treated co-cultured cells. Conclusion The PLGA NPs appeared to act as a promising carrier for cisplatin administration, which was consistent with a higher activation of apoptosis than free drug. PMID:29849458

Influence of the height of the external hexagon and surface treatment on fatigue life of commercially pure titanium dental implants.

PubMed

Gil, Francisco Javier; Aparicio, Conrado; Manero, Jose M; Padros, Alejandro

2009-01-01

This study evaluated the effect of external hexagon height and commonly applied surface treatments on the fatigue life of titanium dental implants. Electropolished commercially pure titanium dental implants (seven implants per group) with three different external hexagon heights (0.6, 1.2, and 1.8 mm) and implants with the highest external hexagon height (1.8 mm) and different surface treatments (electropolishing, grit blasting with aluminium oxide, and acid etching with sulfuric acid) were tested to evaluate their mechanical fatigue life. To do so, 10-Hz triangular flexural load cycles were applied at 37 degrees C in artificial saliva, and the number of load cycles until implant fracture was determined. Tolerances of the hexagon/abutment fit and implant surface roughness were analyzed by scanning electron microscopy and light interferometry. Transmission electron microscopy and electron diffraction analyses of titanium hydrides were performed. First, the fatigue life of implants with the highest hexagon (8,683 +/- 978 load cycles) was more than double that of the implants with the shortest hexagons (3,654 +/- 789 load cycles) (P < .02). Second, the grit-blasted implants had the longest fatigue life of the tested materials (21,393 +/- 2,356 load cycles), which was significantly greater than that of the other surfaces (P < .001). The compressive surface residual stresses induced when blasting titanium are responsible for this superior mechanical response. Third, precipitation of titanium hydrides in grain boundaries of titanium caused by hydrogen adsorption from the acid solution deteriorates the fatigue life of acid-etched titanium dental implants. These implants had the shortest fatigue life (P < .05). The fatigue life of threaded root-form dental implants varies with the height of the external hexagon and/or the surface treatment of the implant. An external hexagon height of 1.8 mm and/or a blasting treatment appear to significantly increase fatigue life of dental implants.

pH-triggered chitosan nanogels via an ortho ester-based linkage for efficient chemotherapy.

PubMed

Yang, Guanqing; Wang, Xin; Fu, Shengxiang; Tang, Rupei; Wang, Jun

2017-09-15

We report on new types of chitosan-based nanogels via an ortho ester-based linkage, used as drug carriers for efficient chemotherapy. First, we synthesized a novel diacrylamide containing ortho ester (OEAM) as an acid-labile cross-linker. Subsequently, methacrylated succinyl-chitosan (MASCS) was prepared and polymerized with OEAM at different molar ratios to give a series of pH-triggered MASCS nanogels. Doxorubicin (DOX) as a model anticancer drug was loaded into MASCS nanogels with a loading content of 16.5%. As expected, with the incorporation of ortho ester linkages, these nanogels showed pH-triggered degradation and drug release at acidic pH values. In vitro cellular uptake shows that the DOX-loaded nanogels could be preferentially internalized by two-dimensional (2D) cells and three-dimensional (3D) multicellular spheroids (MCs), resulting in higher inhibition of the proliferation of tumor cells. In vivo biodistribution and anti-tumor effect were determined in H22 tumor-bearing mice, and the results demonstrate that the acid-labile MASCS nanogels can significantly prolong the blood circulation time of DOX and improve the accumulation in tumor areas, leading to higher therapeutic efficacy. We designed new pH-triggered chitosan nanogels via an ortho ester-based cross-linker for efficient drug-loading and chemotherapy. These drug-loaded nanogels exhibit excellent pH-triggered drug release behavior due to the degradation of ortho ester linkages in mildly acidic environments. In vitro and in vivo results demonstrate that the nanogels could be efficiently internalized by 2D cells and 3D-MCs, improve drug concentration in solid tumors, and lead to higher therapeutic efficacy. To the best of our knowledge, this is the first report on using an ortho ester-based cross-linker to prepare pH-triggered chitosan nanogels as tumor carriers, which may provide a potential route for improved safety and to increase the therapeutic efficacy of anticancer therapy. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Dietary acid load is associated with serum bicarbonate but not insulin sensitivity in chronic kidney disease

PubMed Central

Ikizler, H. Omer; Zelnick, Leila; Ruzinski, John; Curtin, Laura; Utzschneider, Kristina M.; Kestenbaum, Bryan; Himmelfarb, Jonathan; de Boer, Ian H.

2015-01-01

Objective In chronic kidney disease (CKD), dietary acid may promote metabolic acidosis and insulin resistance, which in turn may contribute to adverse clinical health outcomes. We examined associations between dietary acid load, serum bicarbonate, and insulin sensitivity in CKD. Design In a cross-sectional study, we collected 3-day prospective food diaries to quantify dietary acid load as net endogenous acid production (NEAP, the nonvolatile acid load produced by the diet’s acid balance) and potential renal acid load (PRAL). We measured urine net acid excretion (NAE) in 24-hour urine samples. Insulin sensitivity was measured by hyperinsulinemic euglycemic clamp. Subjects 42 patients with CKD stages 3–5 attending nephrology clinics in the Pacific Northwest and 21 control subjects (eGFR ≥60mL/min/1.73m2). Main outcome measures Serum bicarbonate and insulin sensitivity (SIclamp). Results Mean age was 60.8±13.6 years and 54% of participants were men. Mean eGFR and serum bicarbonate concentrations were 34.4±13.1 mL/min/1.73m2 and 24.1±2.9 mEq/L for participants with CKD and 88.6±14.5 mL/min/1.73m2 and 26.3±1.8 mEq/L for control subjects, respectively. Mean NEAP, PRAL, and NAE were 58.2±24.3, 9.7±18.4, and 32.1±19.8 mEq/day, respectively. Considering all participants, dietary acid load was significantly, inversely associated with serum bicarbonate, adjusting for age, sex, race, eGFR, BMI, and diuretic use: −1.2 mEq/L per SD NEAP (95% CI −1.8, −0.6, p<0.0001); −0.9 mEq/L bicarbonate per SD PRAL (95% CI −1.5, −0.4, p=0.0005); −0.7 mEq/L bicarbonate per SD NAE (95% CI −1.2, −0.1, p=0.01). These associations were similar in participants with and without CKD. However, neither NEAP, PRAL, nor NAE was significantly associated with SIclamp. Serum bicarbonate was also not significantly associated with SIclamp. Conclusions In CKD, dietary acid load is associated with serum bicarbonate, suggesting that acidosis may be improved by dietary changes, but not with insulin sensitivity. Practical application We observed that a diet with a greater acid load was associated with lower serum bicarbonate but not insulin resistance in patients with chronic kidney disease. It may be beneficial to limit dietary acid in patients with chronic kidney disease to improve metabolic acidosis and its long-term adverse health effects, but additional, experimental studies are needed to establish the safety and usefulness of such interventions. PMID:26508542

Critical loads of atmospheric deposition to Adirondack lake watersheds: A guide for policymakers

USGS Publications Warehouse

Burns, Douglas A.; Sullivan, Timothy J.

2015-01-01

Acid deposition is sometimes referred to as “acid rain,” although part of the acid load reaches the surface by means other than rainfall. In the eastern U.S., acid deposition consists of several forms of sulfur and nitrogen that largely originate as emissions to the atmosphere from sources such as electricity-generating facilities (coal, oil, and natural gas), diesel- and gasoline-burning vehicles, some agricultural activities, and smokestack industries. Acid deposition is known to cause deleterious effects to sensitive ecosystems of which the Adirondack region of New York State provides several well-known and well-studied examples. This largely forested region includes abundant lakes, streams, and wetlands and possesses several landscape features that result in high ecosystem sensitivity to acid deposition. These features include bedrock that weathers slowly, steep slopes, and thin, naturally acidic soils. An ecosystem is described as sensitive to, or affected by, acid deposition if prolonged exposure to acid deposition has resulted in detrimental ecosystem effects. Soils, streams, and lakes that are less sensitive are better able to buffer acid deposition. A principal reason that acidification is a concern for resource managers is because of the changes induced in native biota and their habitat on land and in water. As the chemistry of soils and surface waters in sensitive landscapes changes in response to prolonged exposure to acid deposition, organisms that cannot tolerate high acidity, such as sugar maple trees and many species of fish and aquatic insects, may be gradually eliminated from the ecosystem. Other biota such as red spruce may experience increased stress and reduced growth rates as a result of acidification, exposing these species to increased susceptibility to disease and other natural stressors and perhaps increased mortality. The ecological effects of acid deposition have been documented by extensive research that began in the U.S. in the 1970s and continues today. This report does not provide a detailed discussion of these ecological effects, but interested readers can refer to four publications that provide good summaries of current scientific knowledge of these effects, including extensive reference to previous research in the Adirondacks (Driscoll et al. 2001, Jenkins et al. 2007, Burns et al. 2011, Sullivan 2015).

Oral insulin delivery using P(MAA-g-EG) hydrogels: effects of network morphology on insulin delivery characteristics.

PubMed

Nakamura, Koji; Murray, Robert J; Joseph, Jeffrey I; Peppas, Nicholas A; Morishita, Mariko; Lowman, Anthony M

2004-03-24

Hydrogels of poly(methacrylic acid-g-ethylene glycol) were prepared using different reaction water contents in order to vary the network mesh size, swelling behavior and insulin loading/release kinetics. Gels prepared with greater reaction solvent contents swelled to a greater degree and had a larger network mesh size. All of the hydrogels were able to incorporate insulin and protected it from release in acidic media. At higher pH (7.4), the release rates increased with reaction solvent content. Using a closed loop animal model, all of the insulin loaded formulations produced significant insulin absorption in the upper small intestine combined with hypoglycemic effects. In these studies, bioavailabilities ranged from 4.6% to 7.2% and were dependent on reaction solvent content.

Olive (Olea europaea L.) tree nitrogen status is a key factor for olive oil quality.

PubMed

Erel, Ran; Kerem, Zohar; Ben-Gal, Alon; Dag, Arnon; Schwartz, Amnon; Zipori, Isaac; Basheer, Loai; Yermiyahu, Uri

2013-11-27

The influence of macronutrient status on olive oil properties was studied for three years. Data were analyzed by a multivariate model considering N, P, K, and fruiting year as explanatory factors. Oil quality parameters were primarily associated with N concentration in leaves and fruits which increased with N in irrigation solution. The effect of P on oil quality was mainly indirect since increased P availability increased N accumulation. The potassium level had negligible effects. The oil phenolic content decreased linearly as a function of increased leaf N, indicating protein-phenol competition in leaves. The overall saturation level of the fatty acids decreased with fruit N, resulting in increased polyunsaturated fatty acids. Free fatty acids increased with increased levels of fruit N. High fruit load tended to reduce fruit N and subsequently improve oil quality. The effect of N on oil properties depended solely on its concentration in leaves or fruits, regardless of the cause.

Localised controlled release of simvastatin from porous chitosan-gelatin scaffolds engrafted with simvastatin loaded PLGA-microparticles for bone tissue engineering application.

PubMed

Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Daly, Jacqueline; Chiono, Valeria; Mattu, Clara; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

2016-02-01

Localised controlled release of simvastatin from porous freeze-dried chitosan-gelatin (CH-G) scaffolds was investigated by incorporating simvastatin loaded poly-(dl-lactide-co-glycolide) acid (PLGA) microparticles (MSIMs) into the scaffolds. MSIMs at 10% w/w simvastatin loading were prepared using a single emulsion-solvent evaporation method. The MSIM optimal amount to be incorporated into the scaffolds was selected by analysing the effect of embedding increasing amounts of blank PLGA microparticles (BL-MPs) on the scaffold physical properties and on the in vitro cell viability using a clonal human osteoblastic cell line (hFOB). Increasing the BL-MP content from 0% to 33.3% w/w showed a significant decrease in swelling degree (from 1245±56% to 570±35%). Scaffold pore size and distribution changed significantly as a function of BL-MP loading. Compressive modulus of scaffolds increased with increasing BL-MP amount up to 16.6% w/w (23.0±1.0kPa). No significant difference in cell viability was observed with increasing BL-MP loading. Based on these results, a content of 16.6% w/w MSIM particles was incorporated successfully in CH-G scaffolds, showing a controlled localised release of simvastatin able to influence the hFOB cell proliferation and the osteoblastic differentiation after 11 days. Copyright © 2015 Elsevier B.V. All rights reserved.

Co-precipitation of asiatic acid and poly( l-lactide) using rapid expansion of subcritical solutions into liquid solvents

NASA Astrophysics Data System (ADS)

Sane, Amporn; Limtrakul, Jumras

2011-09-01

Poly( l-lactide) (PLLA) nanoparticles loaded with asiatic acid (AA) were successfully produced by rapid expansion of a subcritical solution into an aqueous receiving solution containing a dispersing agent. A mixture of carbon dioxide (CO2) and ethanol (EtOH) with a weight ratio of 1:1 was used as the solvent for AA and PLLA. Two surfactants, Pluronic F127 and sodium dodecyl sulfate were employed. The former was found to be more effective for stabilizing AA-loaded PLLA nanoparticles, as a rapid expansion into a 0.1 wt% Pluronic F127 solution produced a stable nanosuspension consisting mainly of well-dispersed, individual nanoparticles. The effects of rapid expansion-processing conditions—AA to PLLA weight ratio and pre-expansion temperature (Tpre)—on the size and morphology of composite nanoparticles, and the loading capacity and entrapment efficiency of AA in PLLA nanoparticles, were systematically investigated. It was found that AA-loaded PLLA nanoparticles with a size range of 30-100 nm were consistently fabricated by rapid expansion at Tpre of 70-100 °C and AA to PLLA weight ratios of 1:2 and 1:4, and with a constant pre-expansion pressure of 330 bar. The Tpre and AA to PLLA weight ratio had no significant effects on the size of the nanoparticles. The AA to PLLA weight ratio is a controlling parameter for both the loading capacity and the entrapment efficiency of AA in PLLA nanoparticles. The loading capacity and entrapment efficiency increased from 8-11 to 16-21 wt%, and 38-57 to 50-62 wt%, respectively, when the AA to PLLA weight ratio changed from 1:4 to 1:2. However, increasing the Tpre from 70 to 100 °C decreased both the loading capacity and entrapment efficiency of AA in PLLA nanoparticles by 20-30%.

Copolymerization of Glycolide and ɛ-Caprolactone Using 12-Aminolauric Acid Modified Montmorillonite

NASA Astrophysics Data System (ADS)

Gallos, HAV; Reyes, LQ

2017-09-01

Poly(glycolide-co-ɛ-caprolactone) (PGLYCL) nanocomposites were prepared by copolymerization glycolide (GLY) and ɛ-caprolactone (ɛ-CL) in the presence of varying loadings 12-aminolauric acid (12-ALA)-modified montmorillonite. Copolymerization was successfully achieved based on the increase in polymer molecular weight after the reaction determined by gel permeation chromatography (GPC). The amount of the poly(glycolide) block and poly(ɛ-caprolactone) block units in the copolymer, identified by proton nuclear magnetic resonance (1H-NMR) spectroscopy, suggested that the increase in organo-clay loading cause a reduction GLYL: ɛ-CLL ratio. The arrangement of the monomers in the polymer products was elucidated to have an ABA triblock structure, where PCL block is the central block and the PGLY is found at both end of the copolymer. The presence of intercalated and exfoliated silicates in the nanocomposites were observed by x-ray diffraction (XRD) analysis. The biocompatibility of the nanocomposites with NCTC 292 mouse normal fibroblast was high relative to untreated cell cultures using tetrazolium bromide (MTT)-dye reduction assay.

Degradability studies of PLA nanocomposites under controlled water sorption and soil burial conditions

NASA Astrophysics Data System (ADS)

Norazlina, H.; Hadi, A. A.; Qurni, A. U.; Amri, M.; Mashelmie, S.; Kamal, Y.

2018-04-01

Polymer blended nanocomposites based on polylactic acid (PLA) were prepared via a simple melting process and investigated for its biodegradation behaviour. The treated CNTs were surface modified by using acid treatment and characterisations of composites were done by using Fourier Transform Infra-Red (FTIR) and UV-Vis. FTIR spectra and UV-Vis peak confirmed the surface modification of CNTs. The water uptake and weight loss behaviour based on CNTs and m-CNTs loading at different temperatures (25° and 45°C) were studied. It was found that the water absorption and weight loss of nanocomposites increased by the incorporation of CNTs and m-CNTs. Moisture induced degradation of composite samples was significant at elevated temperature. The addition of treated CNTs successfully reduced the water uptake and weight loss of nanocomposites due to less hydrolytic effect of water on nanocomposites. In soil burial test, the weight loss increases with addition of nanofiller. The loading of m-CNT reduced the ability of nanocomposites degradation.

Accumulation, selection and covariation of amino acids in sieve tube sap of tansy (Tanacetum vulgare) and castor bean (Ricinus communis): evidence for the function of a basic amino acid transporter and the absence of a γ-amino butyric acid transporter.

PubMed

Bauer, Susanne N; Nowak, Heike; Keller, Frank; Kallarackal, Jose; Hajirezaei, Mohamad-Reza; Komor, Ewald

2014-09-01

Sieve tube sap was obtained from Tanacetum by aphid stylectomy and from Ricinus after apical bud decapitation. The amino acids in sieve tube sap were analyzed and compared with those from leaves. Arginine and lysine accumulated in the sieve tube sap of Tanacetum more than 10-fold compared to the leaf extracts and they were, together with asparagine and serine, preferably selected into the sieve tube sap, whereas glycine, methionine/tryptophan and γ-amino butyric acid were partially or completely excluded. The two basic amino acids also showed a close covariation in sieve tube sap. The acidic amino acids also grouped together, but antagonistic to the other amino acids. The accumulation ratios between sieve tube sap and leaf extracts were smaller in Ricinus than in Tanacetum. Arginine, histidine, lysine and glutamine were enriched and preferentially loaded into the phloem, together with isoleucine and valine. In contrast, glycine and methionine/tryptophan were partially and γ-amino butyric acid almost completely excluded from sieve tube sap. The covariation analysis grouped arginine together with several neutral amino acids. The acidic amino acids were loaded under competition with neutral amino acids. It is concluded from comparison with the substrate specificities of already characterized plant amino acid transporters, that an AtCAT1-like transporter functions in phloem loading of basic amino acids, whereas a transporter like AtGAT1 is absent in phloem. Although Tanacetum and Ricinus have different minor vein architecture, their phloem loading specificities for amino acids are relatively similar. © 2014 Scandinavian Plant Physiology Society.

Microbial community adaptation influences long-chain fatty acid conversion during anaerobic codigestion of fats, oils, and grease with municipal sludge.

PubMed

Ziels, Ryan M; Karlsson, Anna; Beck, David A C; Ejlertsson, Jörgen; Yekta, Sepehr Shakeri; Bjorn, Annika; Stensel, H David; Svensson, Bo H

2016-10-15

Codigesting fats, oils, and greases with municipal wastewater sludge can greatly improve biomethane recovery at wastewater treatment facilities. Process loading rates of fats, oils, and greases have been previously tested with little knowledge of the digester microbial community structure, and high transient fat loadings have led to long chain fatty acid (LCFA) accumulation and digester upsets. This study utilized recently-developed quantitative PCR assays for syntrophic LCFA-degrading bacteria along with 16S amplicon sequencing to relate changes in microbial community structure to LCFA accumulation during transient loading increases to an anaerobic codigester receiving waste restaurant oil and municipal wastewater sludge. The 16S rRNA gene concentration of the syntrophic β-oxidizing genus Syntrophomonas increased to ∼15% of the Bacteria community in the codigester, but stayed below 3% in the control digester that was fed only wastewater sludge. Methanosaeta and Methanospirillum were the dominant methanogenic genera enriched in the codigester, and together comprised over 80% of the Archaea community by the end of the experimental period. Constrained ordination showed that changes in the codigester Bacteria and Archaea community structures were related to measures of digester performance. Notably, the effluent LCFA concentration in the codigester was positively correlated to the specific loading rate of waste oil normalized to the Syntrophomonas 16S rRNA concentration. Specific loading rates of 0-1.5 × 10(-12) g VS oil/16S gene copies-day resulted in LCFA concentrations below 30 mg/g TS, whereas LCFA accumulated up to 104 mg/g TS at higher transient loading rates. Based on the community-dependent loading limitations found, enhanced biomethane production from high loadings of fats, oils and greases can be achieved by promoting a higher biomass of slow-growing syntrophic consortia, such as with longer digester solids retention times. This work also demonstrates the potential for controlling the loading rate of fats, oils, and greases based on the analysis of the codigester community structure, such as with quantitative PCR measurements of syntrophic LCFA-degrading bacteria abundance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Incorporation of titanate nanosheets to enhance mechanical properties of water-soluble polyamic acid

NASA Astrophysics Data System (ADS)

Harito, C.; Bavykin, Dmitry V.; Walsh, Frank C.

2017-07-01

Pyromeliticdianhydride (PMDA) and 4’,4’-oxydianiline (ODA) were used as monomers of polyimide. To synthesise a water soluble polyimide precursor (polyamic acid salt), triethylamine (TEA) was added to polyamic acid with a TEA/COOH mole ratio of 1:1. Titanate nanosheets were synthesised by solid-state reaction, ion-exchanged with acid, and exfoliated by TEA. Exfoliated titanate nanosheets were mixed with water soluble polyamic acid salt as reinforcing filler. Drop casting was deployed to synthesise polyamic acid/titanate nanosheet nanocomposite films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the morphology and dispersion of nanosheets in the colloidal dispersion and the solid film composite. Modulus and hardness of nanocomposites was provided by nanoindentation. Hardness increased by 90% with addition of 2% TiNS while modulus increased by 103% compared to pure polymer. This behaviour agrees well with Halpin-Tsai theoretical predictions up to 2 wt% filler loading; agglomeration occurs at higher concentrations.

Characteristics of eugenol loaded chitosan-tripolyphosphate particles as affected by initial content of eugenol and their in-vitro release characteristic

NASA Astrophysics Data System (ADS)

Cahyono, B.; A’yun, Qurrotu; Suzery, M.; Hadiyanto

2018-04-01

The aim of this research was to determine encapsulation efficiency, loading capacity and controlled release of eugenol loaded chitosan-tpp products which prepared by coaservation method. The characteristic of eugenol-loaded chitosan showed that %EE and % LC increased by increasing the initial eugenol content. The optimum of %EE (72.63%) and %LC (43.96%) were obtained at the ratio of chitosan to eugenol of 1:1.5. The FTIR spectrum showed the characteristic peaks of eugenol appearing on spectrum of eugenol encapsulated and blue-shift in the hydroxyl band from 3425.58 cm-1 in chitosan-tpp to 3417.86 cm-1 and 3394.72 cm-1 in eugenol loaded chitosan-tpp indicating that eugenol was successfully encapsulated. The surface morphologies of freeze-dried particles with the optimum %EE showed that more surface roughness and porosity than plain particles. Furthermore, the in vitro release of particles with minimum and optimum %EE were also investigated in acid (Simulated Gastric Fluid) and base (Simulated Intestinal Fluid) medium at ambient temperature.

Dietary Acid Load is Associated With Serum Bicarbonate but not Insulin Sensitivity in Chronic Kidney Disease.

PubMed

Ikizler, Halil O; Zelnick, Leila; Ruzinski, John; Curtin, Laura; Utzschneider, Kristina M; Kestenbaum, Bryan; Himmelfarb, Jonathan; de Boer, Ian H

2016-03-01

In chronic kidney disease (CKD), dietary acid may promote metabolic acidosis and insulin resistance, which in turn may contribute to adverse clinical health outcomes. We examined associations between dietary acid load, serum bicarbonate, and insulin sensitivity in CKD. In a cross-sectional study, we collected 3-day prospective food diaries to quantify dietary acid load as net endogenous acid production (NEAP, the nonvolatile acid load produced by the diet's acid balance) and potential renal acid load (PRAL). We measured urine net acid excretion (NAE) in 24-hour urine samples. Insulin sensitivity was measured by hyperinsulinemic euglycemic clamp. Forty-two patients with CKD Stages 3 to 5 attending nephrology clinics in the Pacific Northwest and 21 control subjects (estimated glomerular filtration rate [eGFR] ≥ 60 mL/minute/1.73 m(2)). Serum bicarbonate and insulin sensitivity (SIclamp). Mean age was 60.8 ± 13.6 years, and 54% of participants were men. Mean eGFR and serum bicarbonate concentrations were 34.4 ± 13.1 mL/minute/1.73 m(2) and 24.1 ± 2.9 mEq/L for participants with CKD and 88.6 ± 14.5 mL/minute/1.73 m(2) and 26.3 ± 1.8 mEq/L for control subjects, respectively. Mean NEAP, PRAL, and NAE were 58.2 ± 24.3, 9.7 ± 18.4, and 32.1 ± 19.8 mEq/day, respectively. Considering all participants, dietary acid load was significantly, inversely associated with serum bicarbonate, adjusting for age, gender, race, eGFR, body mass index, and diuretic use: -1.2 mEq/L per standard deviation (SD) NEAP (95% confidence interval [CI] -1.8 to -0.6, P < .0001); -0.9 mEq/L bicarbonate per SD PRAL (95% CI -1.5 to -0.4, P = .0005); -0.7 mEq/L bicarbonate per SD NAE (95% CI -1.2 to -0.1, P = .01). These associations were similar in participants with and without CKD. However, neither NEAP and PRAL nor NAE was significantly associated with SIclamp. Serum bicarbonate was also not significantly associated with SIclamp. In CKD, dietary acid load is associated with serum bicarbonate, suggesting that acidosis may be improved by dietary changes, but not with insulin sensitivity. Published by Elsevier Inc.

Zein nanoparticles as delivery systems for covalently linked and physically entrapped folic acid

NASA Astrophysics Data System (ADS)

Chuacharoen, Thanida; Sabliov, Cristina M.

2017-02-01

Zein nanoparticles covalently linked to folic acid were hypothesized to sustain the release of the folic acid in addition to targeting cancer cells overexpressing folate-binding receptors, whereas zein nanoparticles with physically entrapped folic acid would only be able to control the release of the bioactive without targeting of cancer cells. The two types of particles, folic acid covalently linked zein nanoparticles (ZN-FA nps) and zein nanoparticles with entrapped folic acid (ZN(FA) nps), were synthesized and the covalent link between folic acid and zein was assessed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H NMR). Their size, polydispersity index, zeta potential, morphology, and loading capacity were evaluated by dynamic light scattering (DLS), transmission electron microscopy (TEM), and spectrophotometric technique. The release studies of the folic acid preformed in phosphate-buffered saline (PBS) at 37 °C for 7 days concluded that the release of the loaded folic acid was sustained over 7 days for both systems. The cytotoxicity was investigated using a methyl thiazolyl tetrazolium (MTT) assay, and the results showed that zein nanoparticles were biocompatible to HeLa (an overexpressing folate receptor cells) and A549 (a deficient folate receptor cells) cells, which have different levels of folate receptors on surface and both folic acid nanoparticle systems were able to diminish the adverse toxic effect of folic acid to cells. The increased uptake of ZN-FA nps relative to ZN(FA) nps supported the use of ZN-FA nps as targeting nanoagents to cells overexpressing folate receptors.

Geochemical and lithological factors in acid precipitation

Treesearch

James R. Kramer

1976-01-01

Acid precipitation is altered by interaction with rocks, sediment and soil. A calcareous region buffers even the most intense loading at pH ~8; an alumino silicate region with unconsolidated sediment buffers acid loadings at pH ~6.5; alumino silicate outcrops are generally acidified. Either FeOOH or alumino silicates are probable H+...

A conceptual framework: redefining forest soil's critical acid loads under a changing climate.

PubMed

McNulty, Steven G; Boggs, Johnny L

2010-06-01

Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period. While the ecosystem was not in exceedance of the CAL, long-term nitrogen deposition pre-disposed the forest to other ecological stress. In combination, insects, drought, and nitrogen ultimately combined to cause the observed forest mortality. If any one of these factors were not present, the trees would likely not have died. This paper presents a conceptual framework of the ecosystem consequences of these interactions as well as limited plot level data to support this concept. Future assessments of the use of CAL studies need to account for multiple stress impacts to better understand ecosystem response. Published by Elsevier Ltd.

Impact of pectin esterification on the antimicrobial activity of nisin-loaded pectin particles.

PubMed

Krivorotova, Tatjana; Staneviciene, Ramune; Luksa, Juliana; Serviene, Elena; Sereikaite, Jolanta

2017-01-01

The relationship between pectin structure and the antimicrobial activity of nisin-loaded pectin particles was examined. The antimicrobial activity of five different nisin-loaded pectin particles, i.e., nisin-loaded high methoxyl pectin, low methoxyl pectin, pectic acid, dodecyl pectin with 5.4 and 25% degree of substitution were tested in the pH range of 4.0-7.0 by agar-diffusion assay and agar plate count methods. It was found that the degree of esterification of carboxyl group of galacturonic acid in pectin molecule is important for the antimicrobial activity of nisin-loaded pectin particles. Nisin-loaded particles prepared using pectic acid or the pectin with low degree of esterification exhibit higher antimicrobial activity than nisin-loaded high methoxyl pectin particles. Pectins with free carboxyl groups or of low degree of esterification are the most suitable for particles preparation. Moreover, nisin-loaded pectin particles were active at close to neutral or neutral pH values. Therefore, they could be effectively applied for food preservation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:245-251, 2017. © 2016 American Institute of Chemical Engineers.

Lactic acid fermentation from food waste with indigenous microbiota: Effects of pH, temperature and high OLR.

PubMed

Tang, Jialing; Wang, Xiaochang; Hu, Yisong; Zhang, Yongmei; Li, Yuyou

2016-06-01

The effects of pH, temperature and high organic loading rate (OLR) on lactic acid production from food waste without extra inoculum addition were investigated in this study. Using batch experiments, the results showed that although the hydrolysis rate increased with pH adjustment, the lactic acid concentration and productivity were highest at pH 6. High temperatures were suitable for solubilization but seriously restricted the acidification processes. The highest lactic acid yield (0.46g/g-TS) and productivity (278.1mg/Lh) were obtained at 37°C and pH 6. In addition, the lactic acid concentration gradually increased with the increase in OLR, and the semi-continuous reactor could be stably operated at an OLR of 18g-TS/Ld. However, system instability, low lactic acid yield and a decrease in VS removal were noticed at high OLRs (22g-TS/Ld). The concentrations of volatile fatty acids (VFAs) in the fermentation mixture were relatively low but slightly increased with OLR, and acetate was the predominant VFA component. Using high-throughput pyrosequencing, Lactobacillus from the raw food waste was found to selectively accumulate and become dominant in the semi-continuous reactor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intravenous immune globulin in hereditary inclusion body myopathy: a pilot study

PubMed Central

Sparks, Susan; Rakocevic, Goran; Joe, Galen; Manoli, Irini; Shrader, Joseph; Harris-Love, Michael; Sonies, Barbara; Ciccone, Carla; Dorward, Heidi; Krasnewich, Donna; Huizing, Marjan; Dalakas, Marinos C; Gahl, William A

2007-01-01

Background Hereditary Inclusion Body Myopathy (HIBM) is an autosomal recessive, adult onset, non-inflammatory neuromuscular disorder with no effective treatment. The causative gene, GNE, codes for UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, which catalyzes the first two reactions in the synthesis of sialic acid. Reduced sialylation of muscle glycoproteins, such as α-dystroglycan and neural cell adhesion molecule (NCAM), has been reported in HIBM. Methods We treated 4 HIBM patients with intravenous immune globulin (IVIG), in order to provide sialic acid, because IgG contains 8 μmol of sialic acid/g. IVIG was infused as a loading dose of 1 g/kg on two consecutive days followed by 3 doses of 400 mg/kg at weekly intervals. Results For all four patients, mean quadriceps strength improved from 19.0 kg at baseline to 23.2 kg (+22%) directly after IVIG loading to 25.6 kg (+35%) at the end of the study. Mean shoulder strength improved from 4.1 kg at baseline to 5.9 kg (+44%) directly after IVIG loading to 6.0 kg (+46%) at the end of the study. The composite improvement for 8 other muscle groups was 5% after the initial loading and 19% by the end of the study. Esophageal motility and lingual strength improved in the patients with abnormal barium swallows. Objective measures of functional improvement gave variable results, but the patients experienced improvements in daily activities that they considered clinically significant. Immunohistochemical staining and immunoblotting of muscle biopsies for α-dystroglycan and NCAM did not provide consistent evidence for increased sialylation after IVIG treatment. Side effects were limited to transient headaches and vomiting. Conclusion The mild benefits in muscle strength experienced by HIBM patients after IVIG treatment may be related to the provision of sialic acid supplied by IVIG. Other sources of sialic acid are being explored as treatment options for HIBM. PMID:17261181

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix.

PubMed

Jiang, Huixin; Kobayashi, Takaomi

2017-06-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0-30W at 43kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1wt%) on the release behaviors were recorded under 43kHz US exposure at 30W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74μg/mL·min was obtained from 0.54mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1wt% chitin mixture solution under 43kHz US exposure at 30W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. Copyright © 2017 Elsevier B.V. All rights reserved.

Enlargement of halloysite clay nanotube lumen by selective etching of aluminum oxide.

PubMed

Abdullayev, Elshad; Joshi, Anupam; Wei, Wenbo; Zhao, Yafei; Lvov, Yuri

2012-08-28

Halloysite clay tubes have 50 nm diameter and chemically different inner and outer walls (inner surface of aluminum oxide and outer surface of silica). Due to this different chemistry, the selective etching of alumina from inside the tube was realized, while preserving their external diameter (lumen diameter changed from 15 to 25 nm). This increases 2-3 times the tube lumen capacity for loading and further sustained release of active chemical agents such as metals, corrosion inhibitors, and drugs. In particular, halloysite loading efficiency for the benzotriazole increased 4 times by selective etching of 60% alumina within the tubes' lumens. Specific surface area of the tubes increased over 6 times, from 40 to 250 m(2)/g, upon acid treatment.

Impact of enzyme loading on the efficacy and recovery of cellulolytic enzymes immobilized on enzymogel nanoparticles.

PubMed

Samaratunga, Ashani; Kudina, Olena; Nahar, Nurun; Zakharchenko, Andrey; Minko, Sergiy; Voronov, Andriy; Pryor, Scott W

2015-03-01

Cellulase and β-glucosidase were adsorbed on a polyacrylic acid polymer brush grafted on silica nanoparticles to produce enzymogels as a form of enzyme immobilization. Enzyme loading on the enzymogels was increased to a saturation level of approximately 110 μg (protein) mg(-1) (particle) for each enzyme. Enzymogels with varied enzyme loadings were then used to determine the impact on hydrolysis rate and enzyme recovery. Soluble sugar concentrations during the hydrolysis of filter paper and Solka-Floc with the enzymogels were 45 and 53%, respectively, of concentrations when using free cellulase. β-Glucosidase enzymogels showed lower performance; hydrolyzate glucose concentrations were just 38% of those using free enzymes. Increasing enzyme loading on the enzymogels did not reduce net efficacy for cellulase and improved efficacy for β-glucosidase. The use of free cellulases and cellulase enzymogels resulted in hydrolyzates with different proportions of cellobiose and glucose, suggesting differential attachment or efficacy of endoglucanases, exoglucanases, and β-glucosidases present in cellulase mixtures. When loading β-glucosidase individually, higher enzyme loadings on the enzymogels produced higher hydrolyzate glucose concentrations. Approximately 96% of cellulase and 66 % of β-glucosidase were recovered on the enzymogels, while enzyme loading level did not impact recovery for either enzyme.

Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology.

PubMed

Ávila-Lara, Abimael I; Camberos-Flores, Jesus N; Mendoza-Pérez, Jorge A; Messina-Fernández, Sarah R; Saldaña-Duran, Claudia E; Jimenez-Ruiz, Edgar I; Sánchez-Herrera, Leticia M; Pérez-Pimienta, Jose A

2015-01-01

Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading.

Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology

PubMed Central

Ávila-Lara, Abimael I.; Camberos-Flores, Jesus N.; Mendoza-Pérez, Jorge A.; Messina-Fernández, Sarah R.; Saldaña-Duran, Claudia E.; Jimenez-Ruiz, Edgar I.; Sánchez-Herrera, Leticia M.; Pérez-Pimienta, Jose A.

2015-01-01

Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

Enhanced Lipid and Biodiesel Production from Glucose-Fed Activated Sludge: Kinetics an Microbial Community Analysis

EPA Science Inventory

An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon:nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cel...

Electrospun ultra-fine cellulose acetate fibrous mats containing tannic acid-Fe+++ complexes

USDA-ARS?s Scientific Manuscript database

Cellulose acetate (CA) fibrous mats with improved mechanical and antioxidant properties were produced by a simple, scalable and cost-effective electrospinning method. Fibers loaded with small amounts of TA-Fe+++ complexes showed an increase in tensile strength of approximately 117% when compared to ...

Drainage basin control of acid loadings to two Adirondack lakes

NASA Astrophysics Data System (ADS)

Booty, W. G.; Depinto, J. V.; Scheffe, R. D.

1988-07-01

Two adjacent Adirondack Park (New York) calibrated watersheds (Woods Lake and Cranberry Pond), which receive identical atmospheric inputs, generate significantly different unit area of watershed loading rates of acidity to their respective lakes. A watershed acidification model is used to evaluate the watershed parameters which are responsible for the observed differences in acid loadings to the lakes. The greater overall mean depth of overburden on Woods Lake watershed, which supplies a greater buffer capacity as well as a longer retention time of groundwater, appears to be the major factor responsible for the differences.

Spatial and spectral characterization of acid rain stress in Canadian Shield lakes

NASA Technical Reports Server (NTRS)

Marshall, Elizabeth J.; Tanis, Frederick J.

1989-01-01

Results from this study demonstrate that a remote sensor can discriminate lake clarity based upon reflection. The basic hypothesis was that seasonal and multiyear changes in lake optical transparency are indicative of sensitivity to acidic deposition. In many acid-sensitive lakes optical transparency is controlled by the amount of dissolved organic carbon (DOC) present. DOC is a strong absorbing, nonscattering material which has the greatest impact at short visible wavelengths, including Thematic Mapper band 1. Acid-sensitive lakes have high concentrations of aluminum which have been mobilized by acidic components contained in the runoff. Aluminum complexing with DOC is considered to be the primary mechanism to account for observed increases in lake transparency in acid-sensitive lakes. Thus seasonal changes in the optical transparency of lakes should provide an indication of the stress due to acid deposition and loading.

Minimisation of the LCOE for the hybrid power supply system with the lead-acid battery

NASA Astrophysics Data System (ADS)

Kasprzyk, Leszek; Tomczewski, Andrzej; Bednarek, Karol; Bugała, Artur

2017-10-01

The paper presents the methodology of minimisation of the unit cost of production of energy generated in the hybrid system compatible with the lead-acid battery, and used to power a load with the known daily load curve. For this purpose, the objective function in the form of the LCOE and the genetic algorithm method were used. Simulation tests for three types of load with set daily load characteristics were performed. By taking advantage of the legal regulations applicable in the territory of Poland, regarding the energy storing in the power system, the optimal structure of the prosumer solar-wind system including the lead-acid battery, which meets the condition of maximum rated power, was established. An assumption was made that the whole solar energy supplied to the load would be generated in the optimised system.

Using Critical Loads to Look at Improvements in Acidic Surface Water Conditions since the 1990 Amendments to the Clear Air Act: Case Study Adirondack, NY

NASA Astrophysics Data System (ADS)

Lynch, J. A.; Kolian, M. J.; Haeuber, R.

2008-12-01

Acid deposition has affected hundreds of lakes and thousands of miles of headwater streams in the Adirondack region of New York State. The diversity of life in these acidic waters has been greatly reduced. The poor buffering capacity of the thin, acidic soils in the Adirondack Mountains makes the lakes and ponds particularly susceptible to acidification. Since the mid-1990's, lakes in the Adirondack region are finally showing signs of recovery. The good news is that emissions of sulfur dioxide and nitrogen oxides have been reduced and as a result acidic deposition of sulfate and nitrate has decreased in surface waters approximately 26 and 13%, respectively. This has led to improvement in the acid neutralizing capacity (ANC) of these water bodies. Although improvement in water quality is a good sign, it does not tell us if a particular lake or a group of lakes have recovered from decades of acidic deposition. However, the critical loads approach does allow for evaluation of whether a water body has reached recovery for acidic deposition. Critical loads and exceedances for lake surface water and acidity were calculated for 187 lakes in the Adirondack region. The Steady-State Water Chemistry (SSWC) model was used to calculate the critical load, relying on water chemistry data from the TIME/LTM network. An ANC threshold of 50 μeq/L was selected for this case study. Exceedances were calculated from deposition for the period before implementation of the Acid Rain program (ARP) (1989-1991) and for the period of 2004-2006 to judge improvements as a result of the ARP. On average, the critical load for lakes in the Adirondack region is 164 meq/m2/yr, while it is 48 meq/m2/yr for the most sensitive lakes (i.e. ANC less than 100 μeq/L). For the period from 2004 to 2006, 65% of the lakes within the TIME/LTM network continued to receive levels of acid deposition that exceeded the lake's critical load down from 72% of lakes before implementation of the Acid Rain Program. Despite improvement in water quality that has occurred over the past decades in the Adirondack region additional reduction in acidic deposition is needed in order for greater recovery of these sensitive aquatic systems.

Formulation of a novel oxybenzone-loaded nanostructured lipid carriers (NLCs).

PubMed

Sanad, Rania A; Abdelmalak, Nevine Shawky; Elbayoomy, Tahany S; Badawi, Alia A

2010-12-01

The objective of the current study was to formulate oxybenzone into nanostructured lipid carriers (NLCs) to enhance its sunscreening efficacy and safety. NLCs of oxybenzone were prepared by the solvent diffusion method. A complete 2(3) factorial design was used for the evaluation of the prepared oxybenzone NLCs. The study design involves the investigation of the effect of three independent variables namely liquid lipid type (Miglyol 812 and oleic acid), liquid lipid concentration (15% and 30%), and oxybenzone concentration (5% and 10% with respect to total lipids) on the particle size (p.s.) , the entrapment efficiency (EE%) and the in vitro drug release after 8 h. The prepared NLCs were spherical in overall shape and were below 0.8 microm. Miglyol 812 and 30% liquid lipid were found to significantly decrease the p.s. and increase the EE% when compared to oleic acid and 15% liquid lipid. Increasing oxybenzone concentration increased significantly the p.s. but did not affect the EE%. NLCs prepared using Miglyol 812, 15% liquid lipid, and 10% oxybenzone showed slower drug release when compared to those prepared using oleic acid, 30% liquid lipid, and 5% oxybenzone, respectively. The candidate oxybenzone-loaded NLC dispersion was then formulated into gel. The incorporation of oxybenzone into NLCs greatly increased the in vitro sun protection factor and erythemal UVA protection factor of oxybenzone more than six- and eightfold, respectively, while providing the advantage of overcoming side effects of free oxybenzone as evidenced by very low irritation potential.

Volcanic nutrient inputs and trophic state of Lake Caviahue, Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Pedrozo, Fernando L.; Temporetti, Pedro F.; Beamud, Guadalupe; Diaz, Mónica M.

2008-12-01

The strategies for eutrophication control, remediation, and policy management are often defined for neutral to alkaline freshwater systems, as they are most suitable for human use. The influence of nutrients on eutrophication in a naturally-acidic lake is poorly known. The main purpose of the present work is to evaluate the significance of volcanic nutrients in the control of the trophic state of the acidic Lake Caviahue, located at North Patagonia, Argentina. Acidic water systems were most studied on artificial acidified lakes, such as mining lakes in Germany or pit lakes in the United States. Lake Caviahue received a very high P load (42-192 ton P/yr) and low N load (14 ton N/yr), mainly as ammonium with quite low N:P ratios (< 1.0). The magmatic activity of the Copahue volcano represents the main natural contribution of nutrients and acidity to the Lake Caviahue. The lake is oligotrophic in terms of CHLa. Neither the transparency nor the nutrient, dissolved or particulate, contents are to date representative of the trophic state of the lake. High P loads do not imply the eutrophication of the lake. We suggest that nitrogen and not phosphorus represents the key control nutrient in volcanically acidified lakes as TON was better related to CHLa observed (0.13-0.36 mg/m 3) in the lake. The pH increased around one unit (pH 2.0-3.0) during the last five years suggesting that the lake has not yet returned to a stable state.

Microbial activity and community diversity in a variable charge soil as affected by cadmium exposure levels and time*

PubMed Central

Shentu, Jia-li; He, Zhen-li; Yang, Xiao-e; Li, Ting-qiang

2008-01-01

Effects of cadmium (Cd) on microbial biomass, activity and community diversity were assessed in a representative variable charge soil (Typic Aquult) using an incubation study. Cadmium was added as Cd(NO3)2 to reach a concentration range of 0~16 mg Cd/kg soil. Soil extractable Cd generally increased with Cd loading rate, but decreased with incubation time. Soil microbial biomass was enhanced at low Cd levels (0.5~1 mg/kg), but was inhibited consistently with increasing Cd rate. The ratio of microbial biomass C/N varied with Cd treatment levels, decreasing at low Cd rate (<0.7 mg/kg available Cd), but increasing progressively with Cd loading. Soil respiration was restrained at low Cd loading (<1 mg/kg), and enhanced at higher Cd levels. Soil microbial metabolic quotient (MMQ) was generally greater at high Cd loading (1~16 mg/kg). However, the MMQ is also affected by other factors. Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates. Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids (PLFAs) for Gram-negative bacteria and actinomycetes, while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination. PMID:18357628

Efficacy of the biomaterials 3wt%-nanostrontium-hydroxyapatite-enhanced calcium phosphate cement (nanoSr-CPC) and nanoSr-CPC-incorporated simvastatin-loaded poly(lactic-co-glycolic-acid) microspheres in osteogenesis improvement: An explorative multi-phase experimental in vitro/vivo study.

PubMed

Masaeli, Reza; Jafarzadeh Kashi, Tahereh Sadat; Dinarvand, Rassoul; Rakhshan, Vahid; Shahoon, Hossein; Hooshmand, Behzad; Mashhadi Abbas, Fatemeh; Raz, Majid; Rajabnejad, Alireza; Eslami, Hossein; Khoshroo, Kimia; Tahriri, Mohammadreza; Tayebi, Lobat

2016-12-01

The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA+nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P<0.05). Histomorphometry showed greater bone formation after 4weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n=30, ANOVA P<0.05). METHODS AND RESULTS PERTAINING TO SIM-LOADED PLGA MICROSPHERES+NANOSTRONTIUM-CPC COMPOSITE: After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n=50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96±1.01), bone materials (32.28±4.03), nanostrontium-CPC (24.84±2.6), nanostrontium-CPC-simvastatin (40.12±3.29), and SIM-loaded PLGA+nanostrontium-CPC (44.8±6.45) (ANOVA P<0.001). All the pairwise comparisons were significant (Tukey P<0.01), except that of nanostrontium-CPC-simvastatin and SIM-loaded PLGA+nanostrontium-CPC. This confirmed the efficacy of the SIM-loaded PLGA+nanostrontium-CPC composite, and its superiority over all materials except SIM-containing nanostrontium-CPC. Copyright © 2016 Elsevier B.V. All rights reserved.

[PLA-O-CMC nanoparticles: HGF loading and delivery behaviors in vitro].

PubMed

Li, Zhifeng; Chen, Zhong; Chang, Ren'an

2011-04-01

This paper is aimed to observe the hepatocyte growth factor (HGF) loading and delivery ability of polylactic acid and oxygen carboxymethylated chitosan copolyer nanoparticles (PLA-O-CMC NPs). We prepared PLA-O-CMC NPs loaded with HGF by ultrasound in combination with magnetic stirring method. The NPs were characterized by transmission electron microscopy, embedding ratio; drug loading and drug delivery behaviors were observed by ELISA. The characteristics of PLA-O-CMC NPs loaded with HGF showed that the mean size was 139. 82 nm, polydispersity was 0.108, maximal HGF-embedding ratio was 76. 32%. The cumulative HGF release gradually increased in the first 24 hours in vitro, with sharp increasing in the first 7 hours, and moderate and steady increasing in the following 17 hours. The HGF had a burst release in the first 24 hours, and in this process the released HGF took up 36.7% of the whole release. From the second day,the HGF release decreased obviously, while it kept on releasing steadily (45-55 ng/d) for quite long time up to 30 days. The experiment proved that PLA-O-CMC NPs is a favourable carrier of HGF. PLA-O-CMC NPs loaded with HGF could rapidly release HGF in vitro. The released HGF reached the effective drug concentration and maintained the certain effective drug concentration for a long time.

A double blind placebo controlled randomized trial of the effect of acute uric acid changes on inflammatory markers in humans: A pilot study

PubMed Central

Milaneschi, Yuri; Zhang, Yongqing; Becker, Kevin G.; Zukley, Linda; Ferrucci, Luigi

2017-01-01

Uric acid has been linked with increased risk of chronic disease such as cardiovascular disease and this association has been attributed to a pro-inflammatory effect. Indeed, observational studies have shown that high uric acid is associated with high level of pro-inflammatory cytokines in the blood. However, whether high uric acid directly affects inflammation or rather represents a parallel defensive antioxidant mechanism in response to pathology that causes inflammation is unknown. To determine whether acute increase or decrease uric acid levels affects inflammation in healthy individuals, a randomized, placebo-controlled, double blind clinical study of uric acid or rasburicase with 20 healthy volunteers in each treatment-placebo group was conducted at the National Institute on Aging (NIA) Clinical Research Unit (CRU) at Harbor Hospital in Baltimore, MD. Change in inflammatory response was assessed by administering an oral lipid tolerance before and after the treatment of uric acid, rasburicase and placebo. Following uric acid administration, there was an accentuated increase in IL-6 during the oral lipid tolerance test (P<0.001). No significant differences were observed after lowering of uric acid with rasburicase. No side effects were reported throughout the trial. In health individuals, acute increase in uric acid results in an increased IL-6 response when challenged with lipid load. Such effect of amplification of inflammatory response may explain the higher risk of chronic diseases observed in subclinical hyperuricemia in observational studies. Trial Registration: ClinicalTrials.gov NCT01323335 PMID:28786993

Beech wood Fagus sylvatica dilute-acid hydrolysate as a feedstock to support Chlorella sorokiniana biomass, fatty acid and pigment production.

PubMed

Miazek, Krystian; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2017-04-01

This work evaluates the possibility of using beech wood (Fagus sylvatica) dilute-acid (H 2 SO 4 ) hydrolysate as a feedstock for Chlorella sorokiniana growth, fatty acid and pigment production. Neutralized wood acid hydrolysate, containing organic and mineral compounds, was tested on Chlorella growth at different concentrations and compared to growth under phototrophic conditions. Chlorella growth was improved at lower loadings and inhibited at higher loadings. Based on these results, a 12% neutralized wood acid hydrolysate (Hyd12%) loading was selected to investigate its impact on Chlorella growth, fatty acid and pigment production. Hyd12% improved microalgal biomass, fatty acid and pigment productivities both in light and in dark, when compared to photoautotrophic control. Light intensity had substantial influence on fatty acid and pigment composition in Chlorella culture during Hyd12%-based growth. Moreover, heterotrophic Chlorella cultivation with Hyd12% also showed that wood hydrolysate can constitute an attractive feedstock for microalgae cultivation in case of lack of light. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surface modification of protein enhances encapsulation in chitosan nanoparticles

NASA Astrophysics Data System (ADS)

Koyani, Rina D.; Andrade, Mariana; Quester, Katrin; Gaytán, Paul; Huerta-Saquero, Alejandro; Vazquez-Duhalt, Rafael

2018-04-01

Chitosan nanoparticles have a huge potential as nanocarriers for environmental and biomedical purposes. Protein encapsulation in nano-sized chitosan provides protection against inactivation, proteolysis, and other alterations due to environmental conditions, as well as the possibility to be targeted to specific tissues by ligand functionalization. In this work, we demonstrate that the chemical modification of the protein surface enhances the protein loading in chitosan nanocarriers. Encapsulation of green fluorescent protein and the cytochrome P450 was studied. The increase of electrostatic interactions between the free amino groups of chitosan and the increased number of free carboxylic groups in the protein surface enhance the protein loading, protein retention, and, thus, the enzymatic activity of chitosan nanoparticles. The chemical modification of protein surface with malonic acid moieties reduced drastically the protein isoelectric point increasing the protein interaction with the polycationic biomaterial and chitosan. The chemical modification of protein does not alter the morphology of chitosan nanoparticles that showed an average diameter of 18 nm, spheroidal in shape, and smooth surfaced. The strategy of chemical modification of protein surface, shown here, is a simple and efficient technique to enhance the protein loading in chitosan nanoparticles. This technique could be used for other nanoparticles based on polycationic or polyanionic materials. The increase of protein loading improves, doubtless, the performance of protein-loaded chitosan nanoparticles for biotechnological and biomedical applications.

Unveiling the oxidative metabolism of Achatina fulica (Mollusca: Gastropoda) experimentally infected to Angiostrongylus cantonensis (Nematoda: Metastrongylidae).

PubMed

Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Garcia, Juberlan; Mota, Esther Maria; Castro, Rosane Nora; Pontes, Emerson Guedes; Pinheiro, Jairo

2018-06-01

For the first time, alterations in the oxidative metabolism of Achatina fulica experimentally infected with different parasite loads of Angiostrongylus cantonensis were determined. For this, the hemolymph activities of lactate dehydrogenase (LDH) and hexokinase and the glucose concentrations in the hemolymph, as well as the polysaccharide reserves in the digestive gland and cephalopedal mass, were assessed. Additionally, the contents of some carboxylic acids in the hemolymph of infected and uninfected snails were determined by high-performance liquid chromatography (HPLC), permitting a better understanding of the alterations related to the host's oxidative metabolism. As the main results, activation of oxidative pathways, such as the glycolytic pathway, was demonstrated in response to the increase in the activity of hexokinase. This tendency was confirmed by the decrease in the contents of glucose in the hemolymph of parasitized snails, indicating that the infection by A. cantonensis alters the host's metabolism, and that these changes are strongly influenced by the parasite load. This metabolic scenario was accompanied by activation of the anaerobic fermentative metabolism, indicated not only by an increase in the activity of (LDH), but also by a reduction of the content of pyruvic acid and accumulation of lactic acid in the hemolymph of parasitized snails. In this circumstance, maintenance of the host's redox balance occurs through activation of the fermentative pathways, and LDH plays a central role in this process. Together, the results indicate that A. cantonensis infection induces activation of the anaerobic metabolism of A. fulica, characterized not only by the accumulation of lactic acid, but also by a reduction in the pyruvic acid and oxalic acid contents in the hemolymph of the infected snails.

EFFECTS OF ZOLEDRONIC ACID ON OOFORECTOMIZED RATS' TIBIAE: A PROSPECTIVE AND RANDOMIZED STUDY

PubMed Central

Alves Pereira, Fernando Roberto; Dutra, Ricardo César; Reis Olímpio, Thiago César; Müller, Sérgio Swain; Palacio, Evandro Pereira

2015-01-01

To investigate clinical, biomechanic and histomorphometric effects of zoledronic acid on osteoporotic rats’ tibiae after bilateral ooforectomy. Methods: 40 female Wistar (Rattus novergicus albinus) rats were prospectively studied. On the 60th day of life, the animals were randomized into two groups according to the surgical procedure: bilateral ooforectomy (O) (n=20) and sham surgery (“sham”) (P) (n=20). After 30 days, the animals were divided into four groups, according to the administration of zoledronic acid (ZA) 0.1mg/kg or distilled water (DW): OZA (n=10), ODW (n=10), PZA (n=10) and PDW (n=10). After 12 months, the animals were sacrificed, and had their tibiae assessed. In the clinical study, animals’ weight was considered; in the biomechanical study, compressive assays were applied and, in the histomorphometric analysis, the bone trabecular area was determined. Results: “O” groups showed a significantly greater weight gain than “P” groups (p=0.005). Groups OZA and PZA showed an insignificant weight gain when compared to ODW (p=0.47) and PDW (p=0.68). The groups receiving zoledronic acid and distilled water were able to bear maximum load, similar (p=0.2), at the moment of fracture. In the groups receiving zoledronic acid, an insignificant increase of the bone trabecular area was found when compared to the groups receiving distilled water (p=0.21). There was a positive correlation between trabecular area and maximum load (p=0.04; r=0.95). Conclusion: Zoledronic acid did not significantly influence animals’ weight. The results showed an insignificant increase both of the tibial shaft bone resistance and the bone trabecular area. PMID:26998455

Responses of 20 lake-watersheds in the Adirondack region of New York to historical and potential future acidic deposition.

PubMed

Zhou, Qingtao; Driscoll, Charles T; Sullivan, Timothy J

2015-04-01

Critical loads (CLs) and dynamic critical loads (DCLs) are important tools to guide the protection of ecosystems from air pollution. In order to quantify decreases in acidic deposition necessary to protect sensitive aquatic species, we calculated CLs and DCLs of sulfate (SO4(2-))+nitrate (NO3-) for 20 lake-watersheds from the Adirondack region of New York using the dynamic model, PnET-BGC. We evaluated lake water chemistry and fish and total zooplankton species richness in response to historical acidic deposition and under future deposition scenarios. The model performed well in simulating measured chemistry of Adirondack lakes. Current deposition of SO4(2-)+NO3-, calcium (Ca2+) weathering rate and lake acid neutralizing capacity (ANC) in 1850 were related to the extent of historical acidification (1850-2008). Changes in lake Al3+ concentrations since the onset of acidic deposition were also related to Ca2+ weathering rate and ANC in 1850. Lake ANC and fish and total zooplankton species richness were projected to increase under hypothetical decreases in future deposition. However, model projections suggest that lake ecosystems will not achieve complete chemical and biological recovery in the future. Copyright © 2014. Published by Elsevier B.V.

Target loads of atmospheric sulfur deposition for the protection and recovery of acid-sensitive streams in the Southern Blue Ridge Province

Treesearch

Timothy Sullivan; Bernard Cosby; William Jackson

2011-01-01

An important tool in the evaluation of acidification damage to aquatic and terrestrial ecosystems is the critical load (CL), which represents the steady-state level of acidic deposition below which ecological damage would not be expected to occur, according to current scientific understanding. A deposition load intended to be protective of a specified resource...

Very Low-Protein Diet (VLPD) Reduces Metabolic Acidosis in Subjects with Chronic Kidney Disease: The "Nutritional Light Signal" of the Renal Acid Load.

PubMed

Di Iorio, Biagio Raffaele; Di Micco, Lucia; Marzocco, Stefania; De Simone, Emanuele; De Blasio, Antonietta; Sirico, Maria Luisa; Nardone, Luca

2017-01-17

Metabolic acidosis is a common complication of chronic kidney disease; current guidelines recommend treatment with alkali if bicarbonate levels are lower than 22 mMol/L. In fact, recent studies have shown that an early administration of alkali reduces progression of CKD. The aim of the study is to evaluate the effect of fruit and vegetables to reduce the acid load in CKD. We conducted a case-control study in 146 patients who received sodium bicarbonate. Of these, 54 patients assumed very low-protein diet (VLPD) and 92 were controls (ratio 1:2). We calculated every three months the potential renal acid load (PRAL) and the net endogenous acid production (NEAP), inversely correlated with serum bicarbonate levels and representing the non-volatile acid load derived from nutrition. Un-paired T -test and Chi-square test were used to assess differences between study groups at baseline and study completion. Two-tailed probability values ≤0.05 were considered statistically significant. At baseline, there were no statistical differences between the two groups regarding systolic blood pressure (SBP), diastolic blood pressure (DBP), protein and phosphate intake, urinary sodium, potassium, phosphate and urea nitrogen, NEAP, and PRAL. VLPD patients showed at 6 and 12 months a significant reduction of SBP ( p < 0.0001), DBP ( p < 0.001), plasma urea ( p < 0.0001) protein intake ( p < 0.0001), calcemia ( p < 0.0001), phosphatemia ( p < 0.0001), phosphate intake ( p < 0.0001), urinary sodium ( p < 0.0001), urinary potassium ( p < 0.002), and urinary phosphate ( p < 0.0001). NEAP and PRAL were significantly reduced in VLPD during follow-up. VLPD reduces intake of acids; nutritional therapy of CKD, that has always taken into consideration a lower protein, salt, and phosphate intake, should be adopted to correct metabolic acidosis, an important target in the treatment of CKD patients. We provide useful indications regarding acid load of food and drinks-the "acid load dietary traffic light".

Differential distribution of amino acids in plants.

PubMed

Kumar, Vinod; Sharma, Anket; Kaur, Ravdeep; Thukral, Ashwani Kumar; Bhardwaj, Renu; Ahmad, Parvaiz

2017-05-01

Plants are a rich source of amino acids and their individual abundance in plants is of great significance especially in terms of food. Therefore, it is of utmost necessity to create a database of the relative amino acid contents in plants as reported in literature. Since in most of the cases complete analysis of profiles of amino acids in plants was not reported, the units used and the methods applied and the plant parts used were different, amino acid contents were converted into relative units with respect to lysine for statistical analysis. The most abundant amino acids in plants are glutamic acid and aspartic acid. Pearson's correlation analysis among different amino acids showed that there were no negative correlations between the amino acids. Cluster analysis (CA) applied to relative amino acid contents of different families. Alismataceae, Cyperaceae, Capparaceae and Cactaceae families had close proximity with each other on the basis of their relative amino acid contents. First three components of principal component analysis (PCA) explained 79.5% of the total variance. Factor analysis (FA) explained four main underlying factors for amino acid analysis. Factor-1 accounted for 29.4% of the total variance and had maximum loadings on glycine, isoleucine, leucine, threonine and valine. Factor-2 explained 25.8% of the total variance and had maximum loadings on alanine, aspartic acid, serine and tyrosine. 14.2% of the total variance was explained by factor-3 and had maximum loadings on arginine and histidine. Factor-4 accounted 8.3% of the total variance and had maximum loading on the proline amino acid. The relative content of different amino acids presented in this paper is alanine (1.4), arginine (1.8), asparagine (0.7), aspartic acid (2.4), cysteine (0.5), glutamic acid (2.8), glutamine (0.6), glycine (1.0), histidine (0.5), isoleucine (0.9), leucine (1.7), lysine (1.0), methionine (0.4), phenylalanine (0.9), proline (1.1), serine (1.0), threonine (1.0), tryptophan (0.3), tyrosine (0.7) and valine (1.2).

Injectable and body temperature sensitive hydrogels based on chitosan and hyaluronic acid for pH sensitive drug release.

PubMed

Zhang, Wei; Jin, Xin; Li, Heng; Zhang, Run-Run; Wu, Cheng-Wei

2018-04-15

Hydrogels based on chitosan/hyaluronic acid/β-sodium glycerophosphate demonstrate injectability, body temperature sensitivity, pH sensitive drug release and adhesion to cancer cell. The drug (doxorubicin) loaded hydrogel precursor solutions are injectable and turn to hydrogels when the temperature is increased to body temperature. The acidic condition (pH 4.00) can trigger the release of drug and the cancer cell (Hela) can adhere to the surface of the hydrogels, which will be beneficial for tumor site-specific administration of drug. The mechanical strength, the gelation temperature, and the drug release behavior can be tuned by varying hyaluronic acid content. The mechanisms were characterized using dynamic mechanical analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and fluorescence microscopy. The carboxyl group in hyaluronic acid can form the hydrogen bondings with the protonated amine in chitosan, which promotes the increase of mechanical strength of the hydrogels and depresses the initial burst release of drug from the hydrogel. Copyright © 2018 Elsevier Ltd. All rights reserved.

Monitoring bisphosphonate surface functionalization and acid stability of hierarchically porous titanium zirconium oxides.

PubMed

Ide, Andreas; Drisko, Glenna L; Scales, Nicholas; Luca, Vittorio; Schiesser, Carl H; Caruso, Rachel A

2011-11-01

To take advantage of the full potential of functionalized transition metal oxides, a well-understood nonsilane based grafting technique is required. The functionalization of mixed titanium zirconium oxides was studied in detail using a bisphosphonic acid, featuring two phosphonic acid groups with high surface affinity. The bisphosphonic acid employed was coupled to a UV active benzamide moiety in order to track the progress of the surface functionalization in situ. Using different material compositions, altering the pH environment, and looking at various annealing conditions, key features of the functionalization process were identified that consequently will allow for intelligent material design. Loading with bisphosphonic acid was highest on supports calcined at 650 °C compared to lower calcination temperatures: A maximum capacity of 0.13 mmol g(-1) was obtained and the adsorption process could be modeled with a pseudo-second-order rate relationship. Heating at 650 °C resulted in a phase transition of the mixed binary oxide to a ternary oxide, titanium zirconium oxide in the srilankite phase. This phase transition was crucial in order to achieve high loading of the bisphosphonic acid and enhanced chemical stability in highly acidic solutions. Due to the inert nature of phosphorus-oxygen-metal bonds, materials functionalized by bisphosphonic acids showed increased chemical stability compared to their nonfunctionalized counterparts in harshly acidic solutions. Leaching studies showed that the acid stability of the functionalized material was improved with a partially crystalline srilankite phase. The materials were characterized using nitrogen sorption, X-ray powder diffraction, and UV-vis spectroscopy; X-ray photoelectron spectroscopy was used to study surface coverage with the bisphosphonic acid molecules.

A hybrid composite system of biphasic calcium phosphate granules loaded with hyaluronic acid-gelatin hydrogel for bone regeneration.

PubMed

Faruq, Omar; Kim, Boram; Padalhin, Andrew R; Lee, Gun Hee; Lee, Byong-Taek

2017-10-01

An ideal bone substitute should be made of biocompatible materials that mimic the structure, characteristics, and functions of natural bone. Many researchers have worked on the fabrication of different bone scaffold systems including ceramic-polymer hybrid system. In the present study, we incorporated hyaluronic acid-gelatin hydrogel to micro-channeled biphasic calcium phosphate granules as a carrier to improve cell attachment and proliferation through highly interconnected porous structure. This hybrid system is composed of ceramic biphasic calcium phosphate granules measuring 1 mm in diameter with seven holes and hyaluronic acid-gelatin hydrogel. This combination of biphasic calcium phosphate and hyaluronic acid-gelatin retained suitable characteristics for bone regeneration. The resulting scaffold had a porosity of 56% with a suitable pore sizes. The mechanical strength of biphasic calcium phosphate granule increased after loading hyaluronic acid-gelatin from 4.26 ± 0.43 to 6.57 ± 0.25 MPa, which is highly recommended for cancellous bone substitution. Swelling and degradation rates decreased in the hybrid scaffold compared to hydrogel due to the presence of granules in hybrid scaffold. In vitro cytocompatibility studies were observed by preosteoblasts (MC3T3-E1) cell line and the result revealed that biphasic calcium phosphate/hyaluronic acid-gelatin significantly increased cell growth and proliferation compared to biphasic calcium phosphate granules. Analysis of micro-computed tomography data and stained tissue sections from the implanted samples showed that the hybrid scaffold had good osseointegration and better bone formation in the scaffold one and two months postimplantation. Histological section confirmed the formation of dense collagenous tissue and new bone in biphasic calcium phosphate/hyaluronic acid-gelatin scaffolds at two months. Our study demonstrated that such hybrid biphasic calcium phosphate/hyaluronic acid-gelatin scaffold is a promising system for bone regeneration.

Full scale phosphoric acid fuel cell stack technology development

NASA Technical Reports Server (NTRS)

Christner, L.; Faroque, M.

1984-01-01

The technology development for phosphoric acid fuel cells is summarized. The preparation, heat treatment, and characterization of carbon composites used as bipolar separator plates are described. Characterization included resistivity, porosity, and electrochemical corrosion. High density glassy carbon/graphite composites performed well in long-term fuel cell endurance tests. Platinum alloy cathode catalysts and low-loaded platinum electrodes were evaluated in 25 sq cm cells. Although the alloys displayed an initial improvement, some of this improvement diminished after a few thousand hours of testing. Low platinum loading (0.12 mg/sq cm anodes and 0.3 mg/sq cm cathodes) performed nearly as well as twice this loading. A selectively wetproofed anode backing paper was tested in a 5 by 15 inch three-cell stack. This material may provide for acid volume expansion, acid storage, and acid lateral distribution.

Co-production of bio-ethanol, xylonic acid and slow-release nitrogen fertilizer from low-cost straw pulping solid residue.

PubMed

Huang, Chen; Ragauskas, Arthur J; Wu, Xinxing; Huang, Yang; Zhou, Xuelian; He, Juan; Huang, Caoxing; Lai, Chenhuan; Li, Xin; Yong, Qiang

2018-02-01

A novel bio-refinery sequence yielding varieties of co-products was developed using straw pulping solid residue. This process utilizes neutral sulfite pretreatment which under optimal conditions (160 °C and 3% (w/v) sulfite charge) provides 64.3% delignification while retaining 90% of cellulose and 67.3% of xylan. The pretreated solids exhibited excellent enzymatic digestibility, with saccharification yields of 86.9% and 81.1% for cellulose and xylan, respectively. After pretreatment, the process of semi-simultaneous saccharification and fermentation (S-SSF) and bio-catalysis was investigated. The results revealed that decreased ethanol yields were achieved when solid loading increased from 5% to 30%. An acceptable ethanol yield of 76.8% was obtained at 20% solid loading. After fermentation, bio-catalysis of xylose remaining in fermentation broth resulted in near 100% xylonic acid (XA) yield at varied solid loadings. To complete the co-product portfolio, oxidation ammoniation of the dissolved lignin successfully transformed it into biodegradable slow-release nitrogen fertilizer with excellent agricultural properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Encapsulation artocarpanone and ascorbic acid in O/W microemulsions: Preparation, characterization, and antibrowning effects in apple juice.

PubMed

Dong, Xue; Zhu, Qin; Dai, Yaqing; He, Jianfei; Pan, Hongyang; Chen, Jie; Zheng, Zong-Ping

2016-02-01

The aim of this study is to improve artocarpanone solubility by developing an O/W microemulsion with the evaluation of its antibrowning effects. The chemical and physical stabilities as well as antibrowning effects in apple juice were also evaluated. The formulation of artocarpanone microemulsion consisted of 4% w/w of ethyl butyrate, 10.67% w/w of Tween 80, 5.33% w/w of polyethylene glycol 400, and 80% w/w of water, with a maximum solubility of artocarpanone up to 10.54 ± 0.01 mg/mL, at least 3000-folds increase in solubility compared that in water. Encapsulating artocarpanone and ascorbic acid (VC) into microemulsion simultaneously decreased modest artocarpanone solubility whereas improving its stability in long-term storage. Blank, artocarpanone and artocarpanone-Vc-loaded microemulsions demonstrated steadily during accelerated and long-term storage. Artocarpanone-Vc-loaded microemulsion showed strong antibrowning effects in apple juice at room temperature in 24h, suggesting that artocarpanone-Vc-loaded microemulsion is a good antibrowning agent for apple juices. Copyright © 2015 Elsevier Ltd. All rights reserved.

Responses of amino acids in hindlimb muscles to recovery from hypogravity and unloading by tail-cast suspension

NASA Technical Reports Server (NTRS)

Tischler, M. E.; Henriksen, E. J.; Jacob, S.; Cook, P. H.

1985-01-01

Amino acids were assayed in muscles from rats exposed to 7 days of hypogravity and 12 h of gravity (F) or 6 days of suspension with (R) or without (H) 12 h of loading. In these groups, lower aspartate was common only to the soleus (SOL) relative to control muscles, the smallest difference being in group R. This difference in aspartate for F and H, but not for R, correlated with lower malate suggesting diminution of citric acid cycle intermediates. The R SOL value was increased over the H SOL. Therefore desite 12 h of loading, the F SOL was more comparable to the H SOL. The role of stress in preventing recovery of the F SOL was apparent from the ratios of glutamine/glutamate. Synthesis of glutamine is enhanced by glucocorticoids and is reflected by an increased ratio. In 5 of the 6 F muscles studied, this ratio was greater than in controls. In contrast, the ratio in all R muscles was similar to controls and showed recovery from the values in H muscles. Hence the post-flight treatment of F rats may have produced additional stress. Despite this stress, in some respects the SOL responses to hypogravity were similar to its responses to unloding by suspension.

Standardization of formulations for the acute amino acid depletion and loading tests.

PubMed

Badawy, Abdulla A-B; Dougherty, Donald M

2015-04-01

The acute tryptophan depletion and loading and the acute tyrosine plus phenylalanine depletion tests are powerful tools for studying the roles of cerebral monoamines in behaviour and symptoms related to various disorders. The tests use either amino acid mixtures or proteins. Current amino acid mixtures lack specificity in humans, but not in rodents, because of the faster disposal of branched-chain amino acids (BCAAs) by the latter. The high content of BCAA (30-60%) is responsible for the poor specificity in humans and we recommend, in a 50g dose, a control formulation with a lowered BCAA content (18%) as a common control for the above tests. With protein-based formulations, α-lactalbumin is specific for acute tryptophan loading, whereas gelatine is only partially effective for acute tryptophan depletion. We recommend the use of the whey protein fraction glycomacropeptide as an alternative protein. Its BCAA content is ideal for specificity and the absence of tryptophan, tyrosine and phenylalanine render it suitable as a template for seven formulations (separate and combined depletion or loading and a truly balanced control). We invite the research community to participate in standardization of the depletion and loading methodologies by using our recommended amino acid formulation and developing those based on glycomacropeptide. © The Author(s) 2015.

The comparison of different daidzein-PLGA nanoparticles in increasing its oral bioavailability.

PubMed

Ma, Yiran; Zhao, Xinyi; Li, Jian; Shen, Qi

2012-01-01

The aim of this research was to increase the oral bioavailability of daidzein by the formulations of poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with daidzein. Amongst the various traditional and novel techniques of preparing daidzein-loaded PLGA nanoparticles, daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were selected. The average drug entrapment efficiency, particle size, and zeta potential of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were 81.9% ± 5%, 309.2 ± 14.0 nm, -32.14 ± 2.53 mV and 83.2% ± 7.2%, 323.2 ± 4.8 nm, -18.73 ± 1.68 mV, respectively. The morphological characterization of nanoparticles was observed with scanning electron microscopy by stereological method and the physicochemical state of nanoparticles was valued by differential scanning calorimetry. The in vitro drug-release profile of both nanoparticle formulations fitted the Weibull dynamic equation. Pharmacokinetic studies demonstrated that after oral administration of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles to rats at a dose of 10 mg/kg, relative bioavailability was enhanced about 5.57- and 8.85-fold, respectively, compared to daidzein suspension as control. These results describe an effective strategy for oral delivery of daidzein-loaded PLGA nanoparticles and might provide a fresh approach to enhancing the bioavailability of drugs with poor lipophilic and poor hydrophilic properties.

The comparison of different daidzein-PLGA nanoparticles in increasing its oral bioavailability

PubMed Central

Ma, Yiran; Zhao, Xinyi; Li, Jian; Shen, Qi

2012-01-01

The aim of this research was to increase the oral bioavailability of daidzein by the formulations of poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with daidzein. Amongst the various traditional and novel techniques of preparing daidzein-loaded PLGA nanoparticles, daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were selected. The average drug entrapment efficiency, particle size, and zeta potential of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were 81.9% ± 5%, 309.2 ± 14.0 nm, −32.14 ± 2.53 mV and 83.2% ± 7.2%, 323.2 ± 4.8 nm, −18.73 ± 1.68 mV, respectively. The morphological characterization of nanoparticles was observed with scanning electron microscopy by stereological method and the physicochemical state of nanoparticles was valued by differential scanning calorimetry. The in vitro drug-release profile of both nanoparticle formulations fitted the Weibull dynamic equation. Pharmacokinetic studies demonstrated that after oral administration of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles to rats at a dose of 10 mg/kg, relative bioavailability was enhanced about 5.57- and 8.85-fold, respectively, compared to daidzein suspension as control. These results describe an effective strategy for oral delivery of daidzein-loaded PLGA nanoparticles and might provide a fresh approach to enhancing the bioavailability of drugs with poor lipophilic and poor hydrophilic properties. PMID:22346351

Parameters influencing the course of passive drug loading into lipid nanoemulsions.

PubMed

Göke, Katrin; Bunjes, Heike

2018-05-01

Passive drug loading can be used to effectively identify suitable colloidal lipid carrier systems for poorly water-soluble drugs. This method comprises incubation of preformed carrier systems with drug powder and subsequent determination of the resulting drug load of the carrier particles. Until now, the passive loading mechanism is unknown, which complicates reliable routine use. In this work, the influence of drug characteristics on the course of passive loading was investigated systematically varying drug surface area and drug solubility. Fenofibrate and flufenamic acid were used as model drugs; the carrier system was a trimyristin nanodispersion. Loading progress was analyzed by UV spectroscopy or by a novel method based on differential scanning calorimetry. While increasing drug solubility by micelle incorporation did not speed up passive loading, a large drug surface area and high water solubility were key parameters for fast loading. Since both factors are crucial in drug dissolution as described by the Noyes-Whitney equation, these findings point to a dissolution-diffusion-based passive loading mechanism. Accordingly, passive loading also occurred when drug and carrier particles were separated by a dialysis membrane. Knowledge of the loading mechanism allows optimizing the conditions for future passive loading studies and assessing the limitations of the method. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of lipoic acid topical application on rats skin wound healing.

PubMed

Külkamp-Guerreiro, Irene Clemes; Souza, Marielly Nunes; Bianchin, Mariana Domingues; Isoppo, Mateus; Freitas, Joana Sachetti; Alves, João Alex; Piovezan, Anna Paula; Pohlmann, Adriana Raffin; Guterres, Sílvia Stanisçuaski

2013-10-01

To evaluate the effects of lipoic acid (thioctic acid) topical application on wound healing on rats skin, and the consequences of lipoic acid nanoencapsulation on this process. The model used was the healing activity on wounds induced by surgical incision on rats skin (n = 44). The parameters analyzed (11 days) were wound healing rate and histology (vascular proliferation, polymorphonuclear or mononuclear cells, and collagen synthesis or reepithelialization), after application of free lipoic acid or lipoic acid- loaded nanocapsules. The antioxidant activity of these formulations was evaluated by lipid peroxidation test. It was demonstrated for the first time that the topical application of lipoic acid improves wound healing. On the seventh day after surgery, the animals treated with lipoic acid showed increased healing rate (60.7 ± 8.4%) compared to the negative control group (43.0 ± 17.4%), as so improvement of histological parameters. The nanoencapsulation reverted the pro-oxidant activity presented in vitro by lipoic acid, whereas diminished wound repair. The topical application of lipoic acid produced an increase in the skin wound healing, which may be related to its pro-oxidant activity. On the other hand, the nanoencapsulation of the lipoic acid reversed the pro-oxidant activity, although presented minor healing activity.

Characterizing acid diffusion lengths in chemically amplified resists from measurements of deprotection kinetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patil, Abhijit A.; Pandey, Yogendra Narayan; Doxastakis, Manolis

2014-10-01

The acid-catalyzed deprotection of glassy poly(4-hydroxystyrene-co-tertbutyl acrylate) films was studied with infrared absorbance spectroscopy and stochastic simulations. Experimental data were interpreted with a simple description of subdiffusive acid transport coupled to second-order acid loss. This model predicts key attributes of observed deprotection rates, such as fast reaction at short times, slow reaction at long times, and a nonlinear dependence on acid loading. Fickian diffusion is approached by increasing the post-exposure bake temperature or adding plasticizing agents to the polymer resin. These findings demonstrate that acid mobility and overall deprotection kinetics are coupled to glassy matrix dynamics. To complement the analysismore » of bulk kinetics, acid diffusion lengths were calculated from the anomalous transport model and compared with nanopattern line widths. The consistent scaling between experiments and simulations suggests that the anomalous diffusion model could be further developed into a predictive lithography tool.« less

Connecting Source with Sink: The Role of Arabidopsis AAP8 in Phloem Loading of Amino Acids1[OPEN

PubMed Central

Santiago, James P.; Tegeder, Mechthild

2016-01-01

Allocation of large amounts of nitrogen to developing organs occurs in the phloem and is essential for plant growth and seed development. In Arabidopsis (Arabidopsis thaliana) and many other plant species, amino acids represent the dominant nitrogen transport forms in the phloem, and they are mainly synthesized in photosynthetically active source leaves. Following their synthesis, a broad spectrum of the amino nitrogen is actively loaded into the phloem of leaf minor veins and transported within the phloem sap to sinks such as developing leaves, fruits, or seeds. Controlled regulation of the source-to-sink transport of amino acids has long been postulated; however, the molecular mechanism of amino acid phloem loading was still unknown. In this study, Arabidopsis AMINO ACID PERMEASE8 (AAP8) was shown to be expressed in the source leaf phloem and localized to the plasma membrane, suggesting its function in phloem loading. This was further supported by transport studies with aap8 mutants fed with radiolabeled amino acids and by leaf exudate analyses. In addition, biochemical and molecular analyses revealed alterations in leaf nitrogen pools and metabolism dependent on the developmental stage of the mutants. Decreased amino acid phloem loading and partitioning to sinks led to decreased silique and seed numbers, but seed protein levels were unchanged, demonstrating the importance of AAP8 function for sink development rather than seed quality. Overall, these results show that AAP8 plays an important role in source-to-sink partitioning of nitrogen and that its function affects source leaf physiology and seed yield. PMID:27016446

Solid polymer electrolyte (SPE) fuel cell technology program, phase 2/2A. [testing and evaluations

NASA Technical Reports Server (NTRS)

1976-01-01

Test evaluations were performed on a fabricated single solid polymer electrolyte cell unit. The cell operated at increased current density and at higher performance levels. This improved performance was obtained through a combination of increased temperature, increased reactant pressures, improved activation techniques and improved thermal control over the baseline cell configuration. The cell demonstrated a higher acid content membrane which resulted in increased performance. Reduced catalyst loading and low cost membrane development showed encouraging results.

A quarter century of biomonitoring atmospheric pollution in the Czech Republic.

PubMed

Suchara, Ivan; Sucharová, Julie; Holá, Marie

2017-05-01

The Czech Republic (CZ) had extremely high emissions and atmospheric deposition of pollutants in the second half of the 1980s. Since the beginning of the 1990s, moss, spruce bark and forest floor humus have been used as bioindicators of air quality. In the first half of the 1990s, seven larger areas were found to be affected by high atmospheric deposition loads. Six of these "hot spots" were caused by industrial pollution sources, mainly situated in coal basins in the NW and NE part of the country, and one large area in the SE was affected by increased deposition loads of eroded soil particles. After restructuring of industry in CZ, these hot spots were substantially reduced or even disappeared between 1995 and 2000. Since 2000, only two larger areas with slightly increased levels of industrial pollutant deposition and a larger area affected by soil dust have repeatedly been identified by biomonitoring. The distribution of lead isotope ratios in moss showed the main deposition zones around important emission sources. Very high SO 2 emissions led to extreme acidity of spruce bark extracts (pH of about 2.3) at the end of the 1980s. The rate of increasing bark pH was strikingly similar to the rate of recovery of acid wet deposition measured at forest stations in CZ. By about 2005, when the median pH value in bark increased to about 3.2, the re-colonisation of trees by several epiphyte lichen species was observed throughout CZ. An increase in the accumulation of Chernobyl-derived 137 Cs in bark was detected at about ten sites affected by precipitation during the time when radioactive plumes crossed CZ (1986). Accumulated deposition loads in forest floor humus corresponded to the position of the moss and bark hot spots.

Enhanced anticancer efficacy and tumor targeting through folate-PEG modified nanoliposome loaded with 5-fluorouracil

NASA Astrophysics Data System (ADS)

Le, Van Minh; Tran Nho, Trung Duc; Trieu Ly, Hai; Vo, Thanh Sang; Dung Nguyen, Hoang; Thu Huong Phung, Thi; Zou, Aihua; Liu, Jianwen

2017-03-01

Cancer targeted therapies have attracted considerable attention over the past year. Recently, 5-fluouracil (5-FU), which has high toxicity to normal cells and short half-life associated with rapid metabolism, is one of the most commonly used therapies in the treatment of cancer. In this study the folic acid-conjugated pegylated nanoliposomes were synthesized and then loaded into them with 5-FU to improve the anti-tumor efficacy. The average size of liposomes (LPs) was about 52.7 nm which was identified by TEM. In the liposome uptake studies, the level uptake of folate-conjugated liposomes has increased compared to non-conjugated LPs according to LPs concentration, incubation time and presence of concentration of free folic acid (FA). The MTT assay and apoptotic test were carried out in HCT116 and MCF-7 cells for 24 or 48 h. The results revealed that the folate-PEG modified 5-Fu loaded nanoliposomes had strong cytotoxicity to cancer cell compared to pure 5-FU or PEG modified 5-FU loaded liposomes in a concentration- and time-dependent manner, and mainly enhanced the cancer cell death through folate-mediated endocytosis. Hence, the folate-PEG modified nanoliposome is a potential targeted drug-delivery system for the treatment of FR-positive cancers.

Layer-by-layer polyelectrolyte-polyester hybrid microcapsules for encapsulation and delivery of hydrophobic drugs.

PubMed

Luo, Rongcong; Venkatraman, Subbu S; Neu, Björn

2013-07-08

A two-step process is developed to form layer-by-layer (LbL) polyelectrolyte microcapsules, which are able to encapsulate and deliver hydrophobic drugs. Spherical porous calcium carbonate (CaCO3) microparticles were used as templates and coated with a poly(lactic acid-co-glycolic acid) (PLGA) layer containing hydrophobic compounds via an in situ precipitation gelling process. PLGA layers that precipitated from N-methyl-2-pyrrolidone (NMP) had a lower loading and smoother surface than those precipitated from acetone. The difference may be due to different viscosities and solvent exchange dynamics. In the second step, the successful coating of multilayer polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) onto the PLGA coated CaCO3 microparticles was confirmed with AFM and ζ-potential studies. The release of a model hydrophobic drug, ibuprofen, from these hybrid microcapsules with different numbers of PAH/PSS layers was investigated. It was found that the release of ibuprofen decreases with increasing layer numbers demonstrating the possibility to control the release of ibuprofen with these novel hybrid microcapsules. Besides loading of hydrophobic drugs, the interior of these microcapsules can also be loaded with hydrophilic compounds and functional nanoparticles as demonstrated by loading with Fe3O4 nanoparticles, forming magnetically responsive dual drug releasing carriers.

Tracking acidic pharmaceuticals, caffeine, and triclosan through the wastewater treatment process.

PubMed

Thomas, Paul M; Foster, Gregory D

2005-01-01

Pharmaceuticals are a class of emerging contaminants whose fate in the wastewater treatment process has received increasing attention in past years. Acidic pharmaceuticals (ibuprofen, naproxen, mefenamic acid, ketoprofen, and diclofenac), caffeine, and the antibacterial triclosan were quantified at four different steps of wastewater treatment from three urban wastewater treatment plants. The compounds were extracted from wastewater samples on Waters Oasis hydrophilic-lipophilic balance solid-phase extraction columns, silylated, and analyzed by gas chromatography-mass spectrometry. For the chemicals studied, it was found that the majority of the influent load was removed during secondary treatment (51-99%), yielding expected surface water concentrations of 13 to 56 ng/L.

Acid-catalyzed autohydrolysis of wheat straw to improve sugar recovery.

PubMed

Ertas, Murat; Han, Qiang; Jameel, Hasan

2014-10-01

A comparison study of autohydrolysis and acid-catalyzed autohydrolysis of wheat straw was performed to understand the impact of acid addition on overall sugar recovery. Autohydrolysis combined with refining is capable of achieving sugar recoveries in the mid 70s. If the addition of a small amount of acid is capable of increasing the sugar recovery even higher it may be economically attractive. Acetic, sulfuric, hydrochloric and sulfurous acids were selected for acid-catalyzed autohydrolysis pretreatments. Autohydrolysis with no acid at 190 °C showed the highest total sugar in the prehydrolyzate. Enzymatic hydrolysis was performed for all the post-treated solids with and without refining at enzyme loadings of 4 and 10 FPU/g for 96 h. Acid-catalyzed autohydrolysis at 190 °C with sulfurous acid showed the highest total sugar recovery of 81.2% at 4 FPU/g enzyme charge compared with 64.3% at 190 °C autohydrolysis without acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cytoplasmic calcium levels in protoplasts from the cap and elongation zone of maize roots

NASA Technical Reports Server (NTRS)

Kiss, H. G.; Evans, M. L.; Johnson, J. D.

1991-01-01

Calcium has been implicated as a key component in the signal transduction process of root gravitropism. We measured cytoplasmic free calcium in protoplasts isolated from the elongation zone and cap of primary roots of light-grown, vertically oriented seedlings of Zea mays L. Protoplasts were loaded with the penta-potassium salts of fura-2 and indo-1 by incubation in acidic solutions of these calcium indicators. Loading increased with decreasing pH but the pH dependence was stronger for indo-1 than for fura-2. In the case of fura-2, loading was enhanced only at the lowest pH (4.5) tested. Dyes loaded in this manner were distributed predominantly in the cytoplasm as indicated by fluorescence patterns. As an alternative method of loading, protoplasts were incubated with the acetoxymethylesters of fura-2 and indo-1. Protoplasts loaded by this method exhibited fluorescence both in the cytoplasm and in association with various organelles. Cytoplasmic calcium levels measured using spectrofluorometry, were found to be 160 +/- 40 nM and 257 +/- 27 nM, respectively, in populations of protoplasts from the root cap and elongation zone. Cytoplasmic free calcium did not increase upon addition of calcium to the incubation medium, indicating that the passive permeability to calcium was low.

Determination of chemical-constituent loads during base-flow and storm-runoff conditions near historical mines in Prospect Gulch, upper Animas River watershed, southwestern Colorado

USGS Publications Warehouse

Wirt, Laurie; Leib, K.J.; Bove, D.J.; Mast, M.A.; Evans, J.B.; Meeker, G.P.

1999-01-01

Prospect Gulch is a major source of iron, aluminum, zinc, and other metals to Cement Creek. Information is needed to prioritize remediation and develop strategies for cleanup of historical abandoned mine sites in Prospect Gulch. Chemical-constituent loads were determined in Prospect Gulch, a high-elevation alpine stream in southwestern Colorado that is affected by natural acid drainage from weathering of hydro-thermally altered igneous rock and acidic metal-laden discharge from historical abandoned mines. The objective of the study was to identify metal sources to Prospect Gulch. A tracer solution was injected into Prospect Gulch during water-quality sampling so that loading of geochemical constituents could be calculated throughout the study reach. A thunderstorm occurred during the tracer study, hence, metal loads were measured for storm-runoff as well as for base flow. Data from different parts of the study reach represents different flow conditions. The beginning of the reach represents background conditions during base flow immediately upstream from the Lark and Henrietta mines (samples PG5 to PG45). Other samples were collected during storm runoff conditions (PG100 to PG291); during the first flush of metal runoff following the onset of rainfall (PG303 to PG504), and samples PG542 to PG700 were collected during low-flow conditions. During base-flow conditions, the percentage increase in loads for major constituents and trace metals was more than an order of magnitude greater than the corresponding 36 % increase in stream discharge. Within the study reach, the highest percentage increases for dissolved loads were 740 % for iron (Fe), 465 % for aluminum (Al), 500 % for lead (Pb), 380 % for copper (Cu), 100 % for sulfate (SO4), and 50 % for zinc (Zn). Downstream loads near the mouth of Prospect Gulch often greatly exceeded the loads generated within the study reach but varied by metal species. For example, the study reach accounts for about 6 % of the dissolved-Fe load, 13 % of the dissolved-Al load, and 18 % of the dissolved-Zn load; but probably contributes virtually all of the dissolved Cu and Pb. The greatest downstream gains in dissolved trace-metal loads occurred near waste-rock dumps for the historical mines. The major sources of trace metals to the study reach were related to mining. The major source of trace metals in the reach near the mouth is unknown, however is probably related to weathering of highly altered igneous rocks, although an unknown component of trace metals could be derived from mining sources The late-summer storm dramatically increased the loads of most dissolved and total constituents. The effects of the storm were divided into two distinct periods; (1) a first flush of higher metal concentrations that occurred soon after rainfall began and (2) the peak discharge of the storm runoff. The first flush contained the highest loads of dissolved Fe, total and dissolved Zn, Cu, and Cd. The larger concentrations of Fe and sulfate in the first flush were likely derived from iron hydroxide minerals such as jarosite and schwertmanite, which are common on mine dumps in the Prospect Gulch drainage basin. Peak storm runoff contained the highest measured loads of total Fe, and of total and dissolved calcium, magnesium, silica and Al, which were probably derived from weathering of igneous rocks and clay minerals in the drainage basin.

Helically agitated mixing in dry dilute acid pretreatment enhances the bioconversion of corn stover into ethanol

PubMed Central

2014-01-01

Background Dry dilute acid pretreatment at extremely high solids loading of lignocellulose materials demonstrated promising advantages of no waste water generation, less sugar loss, and low steam consumption while maintaining high hydrolysis yield. However, the routine pretreatment reactor without mixing apparatus was found not suitable for dry pretreatment operation because of poor mixing and mass transfer. In this study, helically agitated mixing was introduced into the dry dilute acid pretreatment of corn stover and its effect on pretreatment efficiency, inhibitor generation, sugar production, and bioconversion efficiency through simultaneous saccharification and ethanol fermentation (SSF) were evaluated. Results The overall cellulose conversion taking account of cellulose loss in pretreatment was used to evaluate the efficiency of pretreatment. The two-phase computational fluid dynamics (CFD) model on dry pretreatment was established and applied to analyze the mixing mechanism. The results showed that the pretreatment efficiency was significantly improved and the inhibitor generation was reduced by the helically agitated mixing, compared to the dry pretreatment without mixing: the ethanol titer and yield from cellulose in the SSF reached 56.20 g/L and 69.43% at the 30% solids loading and 15 FPU/DM cellulase dosage, respectively, corresponding to a 26.5% increase in ethanol titer and 17.2% increase in ethanol yield at the same fermentation conditions. Conclusions The advantage of helically agitated mixing may provide a prototype of dry dilute acid pretreatment processing for future commercial-scale production of cellulosic ethanol. PMID:24387051

Postprandial changes in platelet function and coagulation factors after high-fat meals with different fatty acid compositions.

PubMed

Freese, R; Mutanen, M

1995-09-01

To compare the postprandial effects of three oils differing in their fatty acid composition on platelet aggregation and coagulation. The oils studied were low-erucic acid rapeseed oil (RO, oleic acid 54% of fatty acids), sunflower oil (SO, linoleic acid 64% of fatty acids) and butter oil (BO, saturated fatty acids 62% of fatty acids). The postprandial effects of three fat-loads were followed for 5 h. Division of Nutrition, University of Helsinki. Twelve healthy female subjects (aged 23-38 years) were recruited among university students and employees. Postprandial lipaemia was induced by high-fat meals containing fat (RO, SO or BO) 1 g/kg of body weight, skim-milk powder, sugar, strawberries, and water. Each subject ingested each meal in three separate mornings after an overnight fast. The order of the meals was randomised. Blood samples were taken before and 1, 2.5, and 5 h after the test meal. All three test meals similarly affected platelet aggregation in platelet-rich plasma. Aggregation induced by collagen (0.6, 1 and 2.5 micrograms/ml) decreased during the 5-h period after the meals (P = 0.000). ADP-induced aggregation did not change during the follow-up period after any meal (P = 0.105-0.483). All fat loads increased factor VII coagulant activity (F VII:C) (P = 0.000), but in plasma fibrinogen concentration (P = 0.155) or antithrombin III activity (P = 0.278) no postprandial changes were found. These results show that high-fat meals have acute effects on platelet function and F VII:C in healthy women and that these effects are not mediated through the fatty acid composition of the meals.

Preparation and Oxidation Stability Evaluation of Tea Polyphenols-Loaded Inverse Micro-Emulsion.

PubMed

Lan, Xiaohong; Sun, Jingjing; Yang, Ying; Chen, Mengjie; Liu, Jianhua; Wu, Jinhong; Wang, Zhengwu

2017-05-01

Compared to synthetic antioxidants, tea polyphenols (TPs) has its own advantages in edible oil industry, however, the hydrophilic properties have restricted its applications. In this study, the ternary phase diagram of TPs-loaded micro-emulsion (ME) system was constructed, in which glyceryl monooleate (GMO), Tween80, linoleic acid as the surfactants, ethanol as the co-surfactant and soybean, corn, sunflower oil as the oil phase, have been used for the preparation of ME. The results indicated that a composition of ME (57.5% oil, 18% Tween80, 18% GMO, 4% Linolic acid, and 2.5% water+ethanol) could dissolve maximum water and could stable for 2 mo at room temperature with an average diameter of 6 to 7 nm, as detected by means of dynamic light scattering (DLS). The loaded of TPs into ME led to an increase of particle size to 15 to 16 nm, due to increased polarity of the water phase. The antioxidant capacity of TPs in ME was characterized by the peroxide value (POV) method. The addition of 1% water phase with 0.1 g/mL TPs could retain the POV at low value for 30 d at accelerating temperature 50 °C. Meanwhile, comparing the three edible oil, ME with corn oil has lower conductivity and higher value of POV during the storage. This work provides an efficient and environmentally friendly approach for the preparation of TPs-loaded ME, which is beneficial to the application of TPs in edible oil. © 2017 Institute of Food Technologists®.

Plant based dietary supplement increases urinary pH

PubMed Central

Berardi, John M; Logan, Alan C; Rao, A Venket

2008-01-01

Background Research has demonstrated that the net acid load of the typical Western diet has the potential to influence many aspects of human health, including osteoporosis risk/progression; obesity; cardiovascular disease risk/progression; and overall well-being. As urinary pH provides a reliable surrogate measure for dietary acid load, this study examined whether a plant-based dietary supplement, one marketed to increase alkalinity, impacts urinary pH as advertised. Methods Using pH test strips, the urinary pH of 34 healthy men and women (33.9 +/- 1.57 y, 79.3 +/- 3.1 kg) was measured for seven days to establish a baseline urinary pH without supplementation. After this initial baseline period, urinary pH was measured for an additional 14 days while participants ingested the plant-based nutritional supplement. At the end of the investigation, pH values at baseline and during the treatment period were compared to determine the efficacy of the supplement. Results Mean urinary pH statistically increased (p = 0.03) with the plant-based dietary supplement. Mean urinary pH was 6.07 +/- 0.04 during the baseline period and increased to 6.21 +/- 0.03 during the first week of treatment and to 6.27 +/- 0.06 during the second week of treatment. Conclusion Supplementation with a plant-based dietary product for at least seven days increases urinary pH, potentially increasing the alkalinity of the body. PMID:18990209

SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation, optimization and efficacy evaluation.

PubMed

Dimchevska, Simona; Geskovski, Nikola; Petruševski, Gjorgji; Chacorovska, Marina; Popeski-Dimovski, Riste; Ugarkovic, Sonja; Goracinova, Katerina

2017-03-01

One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol ® F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4 h.

Fenspiride inhibits histamine-induced responses in a lung epithelial cell line.

PubMed

Quartulli, F; Pinelli, E; Broué-Chabbert, A; Gossart, S; Girard, V; Pipy, B

1998-05-08

Using the human lung epithelial WI26VA4 cell line, we investigated the capacity of fenspiride, an anti-inflammatory drug with anti-bronchoconstrictor properties, to interfere with histamine-induced intracellular Ca2+ increase and eicosanoid formation. Histamine and a histamine H1 receptor agonist elicited a rapid and transient intracellular Ca2+ increase (0-60 s) in fluo 3-loaded WI26VA4 cells. This response was antagonized by the histamine H1 receptor antagonist, diphenhydramine, the histamine H2 receptor antagonist, cimetidine, having no effect. Fenspiride (10(-7)-10(-5) M) inhibited the histamine H1 receptor-induced Ca2+ increase. In addition, histamine induced a biphasic increase in arachidonic acid release. The initial rise (0-30 s), a rapid and transient arachidonic acid release, was responsible for the histamine-induced intracellular Ca2+ increase. In the second phase release (15-60 min), a sustained arachidonic acid release appeared to be associated with the formation of cyclooxygenase and lipoxygenase metabolites. Fenspiride (10(-5) M) abolished both phases of histamine-induced arachidonic acid release. These results suggest that anti-inflammatory and antibronchoconstrictor properties of fenspiride may result from the inhibition of these effects of histamine.

Screening of Catalyst and Important Variable for The Esterification of Acrylic Acid with 2 Ethylhexanol

NASA Astrophysics Data System (ADS)

Ahmad, M. A. A.; Chin, S. Y.

2017-06-01

The global demand of 2-ethylhexyl acrylate (2EHA) market has witnessed a significant growth in the past few years and this growth is anticipated to increase in the coming years. 2EHA is one of the basic organic building blocks that mainly used in the production of coatings, adhesives, superabsorbents, thickeners and plastic additives. Homogenous acid-catalysed esterification of acrylic acid (AA) with 2-ethylhexanol (2EH) is commonly used for the production of 2EHA. The homogeneous catalysts such as sulfuric and para-toluene sulfonic acid have resulted the costly and complicated downstream process that generates acidic, corrosive and non-environmental friendly waste. Therefore, it is importance to develop a cheaper process that employing heterogeneous catalysts and alternative raw material from wastewater containing acrylic acid. In this research, the study for the esterification of AA with 2EH catalysed by ion-exchange resin was conducted. The best sulfonic acid functional cation-exchange resin among SK104, SK1B, PK208, PK216, PK228, RCP145, and RCP160 was screened. PK208 outperformed the other resins and it was used subsequently in the parametric studies. The effect of important parameters (initial concentration of acrylic acid (AA), temperature, molar ratio of reactant (AA and 2EH), catalyst loading, and polymerisation inhibitor loading) was studied using 2 factorial design to determine the significant parameters to the esterification. It was found that the initial concentration of AA and temperature were most significantly affecting the esterification of AA with 2EH.

Bactericidal Activity of Usnic Acid-Loaded Electrospun Fibers.

PubMed

Araújo, Evando S; Pereira, Eugênia C; da Costa, Mateus M; da Silva, Nicácio H; de Oliveira, Helinando P

2016-01-01

Usnic acid has been progressively reported in the literature as one of the most important lichen metabolites characterized by a rich diversity of applications such as antifungal, antimicrobial, antiprotozoal and antiviral agent. Particularly, antimicrobial activity of usnic acid can be improved by encapsulation of active molecules in enteric electrospun fibers, allowing the controlled release of active molecule at specific pH. Few relevant patents to the topic have been reviewed and cited. Bactericidal activity of usnic acid-loaded electrospun fibers of Eudragit L-100 and polyvinylpyrrolidone was examined against Staphylococcus aureus using inhibition hales methodology. The controlled release of active material at high pH is established after 10 minutes of interaction with media and results in reasonable activity against S. aureus, as detected by inhibition hales. The strong biological activity of usnic acid-loaded electrospun fibers provides a promising application for corresponding material as a bactericidal agent for wound healing treatment.

Water Quality of a Tropical Montane Cloud Forest Watershed, Monteverde, Costa Rica

NASA Astrophysics Data System (ADS)

Rhodes, A. L.; Guswa, A. J.; Dallas, S.; Kim, E. M.; Katchpole, S.; Newell, S. E.; Pufall, A.

2004-05-01

The Rio Guacimal originates in the Monteverde Cloud Forest Preserve, located on the leeward side of the continental divide through Costa Rica. Agriculture and ecotourism has spurred growth adjacent to the preserve. Continued development coupled with changes in precipitation patterns could stress the quality and quantity of water. This study characterizes water chemistry and surface water hydrology of a 21 km2 headwater catchment to evaluate effects of current and projected land use on water quality. Stream samples have been collected from up to 11 sites since March 2000. Two sites located on tributaries in remote, forested areas serve as references for sites located downstream of agricultural and residential areas. Waters were analyzed for specific conductance, pH, DO, acid neutralizing capacity (ANC), Ca, Mg, Na, NH4, SO4, NO3, Cl, PO4 and dissolved silica. In the upland, forested streams, chemical loading is dominated by mineral weathering and cation exchange reactions. Silica, ANC and base cation concentrations all exceed sum of acid anions. During the dry season, concentrations of all dissolved constituents increase synchronously, but at different magnitudes (SO4 and Cl by 15 μ eq/L; silica by 250 μ mol/L; sum of base cations and ANC by 120 μ eq/L), suggesting that increased baseflow has a greater effect on temporal changes of chemical loads in high-elevation, forested streams than does evapotranspiration. Chemical loads of streams receiving runoff from populated areas are 2-5x more concentrated than the upland sites. Highest concentrations occur in Queb. Sucia (QS), which receives grey-water runoff from residential areas. Acidic runoff decreases the ANC of QS by 90-200 μ eq/L; however high alkalinity (ANC=400-1000 μ eq/L) prevents acidification. Acid anions in streams receiving grey-water runoff throughout the year are most concentrated during the dry season when dilution from precipitation is least. Conversely, a site that receives nonpoint source pollution from agricultural areas has its highest concentrations of acid anions during the wet season when surface runoff is the dominant flowpath.

High dietary protein intake and protein-related acid load on bone health

USDA-ARS?s Scientific Manuscript database

Protein is an essential nutrient for humans and is required for maintaining optimal bone structure and growth. Consumption of high protein diets in excess of the Recommended Dietary Allowance of (0.8 g protein/kg body weight/d) is increasingly popular due to the benefits of protein on preserving lea...

The failure of poly (ether ether ketone) in high speed contacts

NASA Astrophysics Data System (ADS)

Briscoe, B. J.; Stuart, B. H.; Sebastian, S.; Tweedale, P. J.

1993-04-01

The paper describes an experimental study, with an associated analysis incorporating supplementary data, of the anti-boundary lubricating action of an alkane-aliphatic carboxylic acid lubricant system in a poly (ether ether ketone)-mild steel contact. The experiments involve progressively increasing the load in a contact formed between a polymer plate and a rotating steel shaft and estimating the frictional work dissipated. Scuffing is identified when a rapid increase in frictional work is noted at a characteristic normal load. It is shown that the additive induces premature scuffing. Subsidiary data is provided using Raman spectroscopy and hardness probes, and confirms that certain additives such as decanoic acid and dodecylamine will induce surface plasticization in poly (ether ether ketone). The trends in the frictional data have been interpreted using the adhesive model of friction in conjunction with temperature-dependent interfacial theology and bulk mechanical property data. It is proposed that the scuffing process is induced prematurely as a consequence of excessive additive-induced subsurface plasticization. Restricted surface plasticization in this system provides an enhanced self-lubricating capacity.

Fabrication and in vitro release behavior of a novel antibacterial coating containing halogenated furanone-loaded poly(L-lactic acid) nanoparticles on microarc-oxidized titanium

PubMed Central

Cheng, Yicheng; Wu, Jiang; Gao, Bo; Zhao, Xianghui; Yao, Junyan; Mei, Shenglin; Zhang, Liang; Ren, Huifang

2012-01-01

Background Dental implants have become increasingly common for the management of missing teeth. However, peri-implant infection remains a problem, is usually difficult to treat, and may lead eventually to dental implant failure. The aim of this study was to fabricate a novel antibacterial coating containing a halogenated furanone compound, ie, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF)-loaded poly(L-lactic acid) (PLLA) nanoparticles on microarc-oxidized titanium and to evaluate its release behavior in vitro. Methods BBF-loaded PLLA nanoparticles were prepared using the emulsion solvent-evaporation method, and the antibacterial coating was fabricated by cross-linking BBF-loaded PLLA nanoparticles with gelatin on microarc-oxidized titanium. Results The BBF-loaded PLLA nanoparticles had a small particle size (408 ± 14 nm), a low polydispersity index (0.140 ± 0.008), a high encapsulation efficiency (72.44% ± 1.27%), and a fine spherical shape with a smooth surface. The morphology of the fabricated antibacterial coating showed that the BBF-loaded PLLA nanoparticles were well distributed in the pores of the microarc oxidation coating, and were cross-linked with each other and the wall pores by gelatin. The release study indicated that the antibacterial coating could achieve sustained release of BBF for 60 days, with a slight initial burst release during the first 4 hours. Conclusion The novel antibacterial coating fabricated in this study is a potentially promising method for prevention of early peri-implant infection. PMID:23152682

Effect of multi-nutrient insufficiency on markers of one carbon metabolism in young women: response to a methionine load.

PubMed

Katre, P; Joshi, S; Bhat, D S; Deshmukh, M; Gurav, N; Pandit, S; Lubree, H; Marczewski, S; Bennett, C; Gruca, L; Kalyanaraman, K; Naik, S S; Yajnik, C S; Kalhan, S C

2016-06-01

Multi-nutrient insufficiencies as a consequence of nutritional and economic factors are common in India and other developing countries. We have examined the impact of multi-nutrient insufficiency on markers of one carbon (1C) metabolism in the blood, and response to a methionine load in clinically healthy young women. Young women from Pune, India (n=10) and Cleveland, USA (n=13) were studied. Blood samples were obtained in the basal state and following an oral methionine load (50 mg/kg of body weight in orange juice). Plasma concentrations of vitamin B12, folate and B6 were measured in the basal state. The effect of methionine load on the levels of methionine, total homocysteine, cysteine, glutathione and amino acids was examined. Indian women were significantly shorter and lighter compared with the American women and had lower plasma concentration of vitamins B12, folate and B6, essential amino acids and glutathione, but higher concentration of total homocysteine. The homocysteine response to methionine load was higher in Indian women. The plasma concentrations of glycine and serine increased in the Indian women after methionine (in juice) load. A significant negative correlation between plasma B6 and homocysteine (r= -0.70), and plasma folate and glycine and serine levels were observed in the Indian group (P<0.05) but not in the American group. Multi-nutrient insufficiency in the Indian women caused unique changes in markers of whole body protein and 1C metabolism. These data would be useful in developing nutrient intervention strategies.

Reducing the Dietary Acid Load: How a More Alkaline Diet Benefits Patients With Chronic Kidney Disease.

PubMed

Passey, Caroline

2017-05-01

It has been proposed that a low-protein diet will slow progression of chronic kidney disease although studies have not always supported this belief. The accepted practice is that 60% to 70% of protein comes from high biological value (HBV) protein, but this limits patient choice and patients struggle to follow the diet. When a diet with only 30% HBV protein was trialed, there was a significant increase in serum bicarbonate, and patients preferred the diet. The dietary advice given in predialysis clinics was changed. HBV protein was restricted to approximately 50% of total protein, bread and cereal foods were allowed freely, and fruits and vegetables (F&V) were encouraged. Patients who followed the diet have seen a slowing of progression and occasionally regression of their renal function. Both observations and scientific literature indicate that this is because of a reduction in the acid content of the diet. When foods are metabolized, most proteins produce acid, and most F&V produce alkali. A typical 21 st -century diet produces 50 to 100 mEq H + per day which the kidney is challenged to excrete. Acid is excreted with phosphate and is limited to about 45 mEq H + per day. With chronic kidney disease, this falls progressively to below 20 mEq H + per day. Historically, ammonium excretion was believed to be excretion of acid (NH 3 +  + H + → NH 4 + ), but it is now understood to be a by-product in the neutralization of acid by glutamine. The remaining acid is neutralized or stored within the body. Bone and muscle are lost in order to neutralize the acid. Acid also accumulates within cells, and serum bicarbonate falls. The author postulates that reducing the acid load through a low-protein diet with greater use of vegetable proteins and increased F&V intake will slow progression or occasionally improve renal function while maintaining the nutritional status of the individual. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.

PubMed

Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon

2016-07-28

Acne is a multifactorial inflammatory skin disease with high prevalence. In this work, the potential of 3D printing to produce flexible personalised-shape anti-acne drug (salicylic acid) loaded devices was demonstrated by two different 3D printing (3DP) technologies: Fused Deposition Modelling (FDM) and stereolithography (SLA). 3D scanning technology was used to obtain a 3D model of a nose adapted to the morphology of an individual. In FDM 3DP, commercially produced Flex EcoPLA™ (FPLA) and polycaprolactone (PCL) filaments were loaded with salicylic acid by hot melt extrusion (HME) (theoretical drug loading - 2% w/w) and used as feedstock material for 3D printing. Drug loading in the FPLA-salicylic acid and PCL-salicylic acid 3D printed patches was 0.4% w/w and 1.2% w/w respectively, indicating significant thermal degradation of drug during HME and 3D printing. Diffusion testing in Franz cells using a synthetic membrane revealed that the drug loaded printed samples released <187μg/cm(2) within 3h. FPLA-salicylic acid filament was successfully printed as a nose-shape mask by FDM 3DP, but the PCL-salicylic acid filament was not. In the SLA printing process, the drug was dissolved in different mixtures of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) (PEG) that were solidified by the action of a laser beam. SLA printing led to 3D printed devices (nose-shape) with higher resolution and higher drug loading (1.9% w/w) than FDM, with no drug degradation. The results of drug diffusion tests revealed that drug diffusion was faster than with the FDM devices, 229 and 291μg/cm(2) within 3h for the two formulations evaluated. In this study, SLA printing was the more appropriate 3D printing technology to manufacture anti-acne devices with salicylic acid. The combination of 3D scanning and 3D printing has the potential to offer solutions to produce personalised drug loaded devices, adapted in shape and size to individual patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Gossypol-Capped Mitoxantrone-Loaded Mesoporous SiO2 NPs for the Cooperative Controlled Release of Two Anti-Cancer Drugs.

PubMed

Heleg-Shabtai, Vered; Aizen, Ruth; Sharon, Etery; Sohn, Yang Sung; Trifonov, Alexander; Enkin, Natalie; Freage, Lina; Nechushtai, Rachel; Willner, Itamar

2016-06-15

Mesoporous SiO2 nanoparticles, MP-SiO2 NPs, are functionalized with the boronic acid ligand units. The pores of the MP-SiO2 NPs are loaded with the anticancer drug mitoxantrone, and the pores are capped with the anticancer drug gossypol. The resulting two-drug-functionalized MP-SiO2 NPs provide a potential stimuli-responsive anticancer drug carrier for cooperative chemotherapeutic treatment. In vitro experiments reveal that the MP-SiO2 NPs are unlocked under environmental conditions present in cancer cells, e.g., acidic pH and lactic acid overexpressed in cancer cells. The effective unlocking of the capping units under these conditions is attributed to the acidic hydrolysis of the boronate ester capping units and to the cooperative separation of the boronate ester bridges by the lactate ligand. The gossypol-capped mitoxantrone-loaded MP-SiO2 NPs reveals preferential cytotoxicity toward cancer cells and cooperative chemotherapeutic activities toward the cancer cells. The MCF-10A epithelial breast cells and the malignant MDA-MB-231 breast cancer cells treated with the gossypol-capped mitoxantrone-loaded MP-SiO2 NPs revealed after a time-interval of 5 days a cell death of ca. 8% and 60%, respectively. Also, the gossypol-capped mitoxantrone-loaded MP-SiO2 NPs revealed superior cancer-cell death (ca. 60%) as compared to control carriers consisting of β-cyclodextrin-capped mitoxantrone-loaded (ca. 40%) under similar loading of the mitoxantrone drug. The drugs-loaded MP-SiO2 NPs reveal impressive long-term stabilities.

A multifunctional energy-storage system with high-power lead-acid batteries

NASA Astrophysics Data System (ADS)

Wagner, R.; Schroeder, M.; Stephanblome, T.; Handschin, E.

A multifunctional energy storage system is presented which is used to improve the utilization of renewable energy supplies. This system includes three different functions: (i) uninterruptible power supply (UPS); (ii) improvement of power quality; (iii) peak-load shaving. The UPS application has a long tradition and is used whenever a reliable power supply is needed. Additionally, nowadays, there is a growing demand for high quality power arising from an increase of system perturbation of electric grids. Peak-load shaving means in this case the use of renewable energy stored in a battery for high peak-load periods. For such a multifunctional application large lead-acid batteries with high power and good charge acceptance, as well as good cycle life are needed. OCSM batteries as with positive tubular plates and negative copper grids have been used successfully for a multitude of utility applications. This paper gives two examples where multifunctional energy storage systems have started operation recently in Germany. One system was installed in combination with a 1 MW solar plant in Herne and another one was installed in combination with a 2 MW wind farm in Bocholt. At each place, a 1.2 MW h (1 h-rate) lead-acid battery has been installed. The batteries consist of OCSM cells with the standard design but modified according to the special demand of a multifunctional application.

Gallic acid loaded PEO-core/zein-shell nanofibers for chemopreventive action on gallbladder cancer cells.

PubMed

Acevedo, Francisca; Hermosilla, Jeyson; Sanhueza, Claudia; Mora-Lagos, Barbara; Fuentes, Irma; Rubilar, Mónica; Concheiro, Angel; Alvarez-Lorenzo, Carmen

2018-07-01

Coaxial electrospinning was used to develop gallic acid (GA) loaded poly(ethylene oxide)/zein nanofibers in order to improve its chemopreventive action on human gallbladder cancer cells. Using a Plackett-Burman design, the effects of poly(ethylene oxide) and zein concentration and applied voltage on the diameter and morphology index of nanofibers were investigated. Coaxial nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). GA loading efficiency as high as 77% was obtained under optimal process conditions. The coaxial nanofibers controlled GA release in acid and neutral pH medium. Cytotoxicity and reactive oxygen species (ROS) production on gallbladder cancer cell lines GB-d1 and NOZ in the presence of GA-nanofibers were assessed. GA-nanofibers triggered an increase in the cellular cytotoxicity compared with free GA on GB-d1 and NOZ cells. Statistically significant differences were found in ROS levels of GA-nanofibers compared with free GA on NOZ cells. Differently, ROS production on GB-d1 cell line was similar. Based on these results, the coaxial nanofibers obtained in this study under optimized operational conditions offer an alternative for the development of a GA release system with improved chemopreventive action on gallbladder cancer cells. Copyright © 2018 Elsevier B.V. All rights reserved.

Restoration and Purification of Dissolved Organic Nitrogen by Bacteria and Phytoremediation in Shallow Eutrophic Lakes Sediments

NASA Astrophysics Data System (ADS)

Li, Xin; Yue, Yi

2018-06-01

Endogenous organic nitrogen loadings in lake sediments have increased with human activity in recent decades. A 6-month field study from two disparate shallow eutrophic lakes could partly reveal these issues by analysing seasonal variations of biodegradation and phytoremediation in the sediment. This paper describes the relationship between oxidation reduction potential, temperature, microbial activity and phytoremediation in nitrogen cycling by calculation degradative index of dissolved organic nitrogen and amino acid decomposition. The index was being positive in winter and negative in summer while closely positive correlated with biodegradation. Our analysis revealed that rather than anoxic condition, biomass is the primary factor to dissolved organic nitrogen distribution and decomposition. Some major amino acids statistics also confirm the above view. The comparisons of organic nitrogen and amino acid in abundance and seasons in situ provides that demonstrated plants cue important for nitrogen removal by their roots adsorption and immobilization. In conclusion, enhanced microbial activity and phytoremediation with the seasons will reduce the endogenous nitrogen loadings by the coupled mineralization and diagenetic process.

Poly methacrylic acid modified CDHA nanocomposites as potential pH responsive drug delivery vehicles.

PubMed

Victor, Sunita Prem; Sharma, Chandra P

2013-08-01

The objective of this study was to prepare pH sensitive polymethacrylic acid-calcium deficient hydroxyapatite (CDHA) nanocomposites. The CDHA nanoparticles were prepared by coprecipitation method. The modification of CDHA by methacrylic acid (MA) was achieved by AIBN initiated free radical polymerization with sodium bisulphite as catalyst followed by emulsion technique. These nanocomposites with a half life of 8h consisted of high aspect ratio, needle like particles and exhibited an increase in swelling behaviour with pH. The in vivo potential of the nanocomposites was evaluated in vitro by the results of cell aggregation, protein adsorption, MTT assay and haemolytic activity. The invitro loading and release studies using albumin as a model drug indicate that the nanocomposites gave better loading when compared to the CDHA nanoparticles and altered the drug release rates. The nanocomposites also exhibited good uptake on C6 glioma cells as studied by fluorescence microscopy. The results obtained suggest that these nanocomposites have great potential for oral controlled protein delivery and can be extended further for intracellular drug delivery applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Organic loading rate impact on biohydrogen production and microbial communities at anaerobic fluidized thermophilic bed reactors treating sugarcane stillage.

PubMed

Santos, Samantha Christine; Rosa, Paula Rúbia Ferreira; Sakamoto, Isabel Kimiko; Varesche, Maria Bernadete Amâncio; Silva, Edson Luiz

2014-05-01

This study aimed to evaluate the effect of high organic loading rates (OLR) (60.0-480.00 kg COD m(-3)d(-1)) on biohydrogen production at 55°C, from sugarcane stillage for 15,000 and 20,000 mg CODL(-1), in two anaerobic fluidized bed reactors (AFBR1 and AFBR2). It was obtained, for H2 yield and content, a decreasing trend by increasing the OLR. The maximum H2 yield was observed in AFBR1 (2.23 mmol g COD added(-1)). The volumetric H2 production was proportionally related to the applied hydraulic retention time (HRT) of 6, 4, 2 and 1h and verified in AFBR1 the highest value (1.49 L H2 h(-1)L(-1)). Among the organic acids obtained, there was a predominance of lactic acid (7.5-22.5%) and butyric acid (9.4-23.8%). The microbial population was set with hydrogen-producing fermenters (Megasphaera sp.) and other organisms (Lactobacillus sp.). Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of enzyme loading and β-glucosidase supplementation on enzymatic hydrolysis of switchgrass processed by leading pretreatment technologies.

PubMed

Pallapolu, Venkata Ramesh; Lee, Y Y; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Falls, Matthew; Holtzapple, Mark T; Sierra-Ramirez, Rocio; Shi, Jian; Ebrik, Mirvat A; Redmond, Tim; Yang, Bin; Wyman, Charles E; Donohoe, Bryon S; Vinzant, Todd B; Elander, Richard T; Hames, Bonnie; Thomas, Steve; Warner, Ryan E

2011-12-01

The objective of this work is to investigate the effects of cellulase loading and β-glucosidase supplementation on enzymatic hydrolysis of pretreated Dacotah switchgrass. To assess the difference among various pretreatment methods, the profiles of sugars and intermediates were determined for differently treated substrates. For all pretreatments, 72 h glucan/xylan digestibilities increased sharply with enzyme loading up to 25mg protein/g-glucan, after which the response varied depending on the pretreatment method. For a fixed level of enzyme loading, dilute sulfuric acid (DA), SO(2), and Lime pretreatments exhibited higher digestibility than the soaking in aqueous ammonia (SAA) and ammonia fiber expansion (AFEX). Supplementation of Novozyme-188 to Spezyme-CP improved the 72 h glucan digestibility only for the SAA treated samples. The effect of β-glucosidase supplementation was discernible only at the early phase of hydrolysis where accumulation of cellobiose and oligomers is significant. Addition of β-glucosidase increased the xylan digestibility of alkaline treated samples due to the β-xylosidase activity present in Novozyme-188. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of friction between articular cartilage and polyvinyl alcohol hydrogel artificial cartilage.

PubMed

Li, Feng; Wang, Anmin; Wang, Chengtao

2016-05-01

Many biomaterials are being used to repair damaged articular cartilage. In particular, poly vinyl alcohol hydrogel has similar mechanical properties to natural cartilage under compressive and shearing loading. Here, three-factor and two-level friction experiments and long-term tests were conducted to better evaluate its tribological properties. The friction coefficient between articular cartilage and the poly vinyl alcohol hydrogel depended primarily on the three factors of load, speed, and lubrication. When the speed increased from 10 to 20 mm/s under a load of 10 N, the friction coefficient increased from 0.12 to 0.147. When the lubricant was changed from Ringer's solution to a hyaluronic acid solution, the friction coefficient decreased to 0.084 with loads as high as 22 N. The poly vinyl alcohol hydrogel was severely damaged and lost its top surface layers, which were transferred to the articular cartilage surface. Wear was observed in the surface morphologies, which indicated the occurrence of surface adhesion of bovine cartilage. Surface fatigue and adhesive wear was the dominant wear mechanism.

Inhibitory effect of cervical trachea and chest wall vibrations on cough reflex sensitivity and perception of urge-to-cough in healthy male never-smokers

PubMed Central

2013-01-01

Background Non-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the effect of mechanical vibration of cervical trachea, chest wall and femoral muscle on cough reflex sensitivity, perceptions of urge-to-cough as well as dyspnea. Methods Twenty-four healthy male never-smokers were investigated for cough reflex sensitivity, perceptions of the urge-to-cough and dyspnea with or without mechanical vibration. Cough reflex sensitivity and urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. Mechanical vibration was applied by placing a vibrating tuning fork on the skin surface of cervical trachea, chest wall and femoral muscle. Results Cervical trachea vibration significantly increased cough reflex threshold, as expressed by the lowest concentration of citric acid that elicited five or more coughs (C5), and urge-to-cough threshold, as expressed by the lowest concentration of citric acid that elicited urge-to-cough (Cu), but did not significantly affect dypnea sensation during inspiratory resistive loading. On the other hand, the chest wall vibration not only significantly increased C5 and Cu but also significantly ameliorated the load-response curve of dyspnea sensation. Conclusions Both cervical and trachea vibrations significantly inhibited cough reflex sensitivity and perception of urge-to-cough. These vibration techniques might be options for symptomatic cough management. PMID:24088411

Promotion effect of nickel loaded on CdS for photocatalytic H2 production in lactic acid solution

NASA Astrophysics Data System (ADS)

Chen, Shu; Chen, Xiaoping; Jiang, Qizhong; Yuan, Jian; Lin, Caifang; Shangguan, Wenfeng

2014-10-01

Low-cost Ni modified CdS was prepared via a hydrothermal reduction method. The hydrogen production activity of CdS loaded with 5 wt% Ni under visible light was even higher than that of the one loaded with 0.5 wt% Pt. The highest H2 evolution rate (3004.8 μmol h-1) occurred when the concentration of sacrificial agent (lactic acid) was 50 vol%. The nickel can quickly transfer excited electrons and enhance the photocatalytic H2 production activity. It was also found that the hydrogen evolution in this system was generated steadily from both water and lactic acid.

Photochemical processing of diesel fuel emissions as a large secondary source of isocyanic acid (HNCO)

NASA Astrophysics Data System (ADS)

Link, M. F.; Friedman, B.; Fulgham, R.; Brophy, P.; Galang, A.; Jathar, S. H.; Veres, P.; Roberts, J. M.; Farmer, D. K.

2016-04-01

Isocyanic acid (HNCO) is a well-known air pollutant that affects human health. Biomass burning, smoking, and combustion engines are known HNCO sources, but recent studies suggest that secondary production in the atmosphere may also occur. We directly observed photochemical production of HNCO from the oxidative aging of diesel exhaust during the Diesel Exhaust Fuel and Control experiments at Colorado State University using acetate ionization time-of-flight mass spectrometry. Emission ratios of HNCO were enhanced, after 1.5 days of simulated atmospheric aging, from 50 to 230 mg HNCO/kg fuel at idle engine operating conditions. Engines operated at higher loads resulted in less primary and secondary HNCO formation, with emission ratios increasing from 20 to 40 mg HNCO/kg fuel under 50% load engine operating conditions. These results suggest that photochemical sources of HNCO could be more significant than primary sources in urban areas.

Influence of the organic loading rate on the performance and the granular sludge characteristics of an EGSB reactor used for treating traditional Chinese medicine wastewater.

PubMed

Li, Weiguang; Su, Chengyuan; Liu, Xingzhe; Zhang, Lei

2014-01-01

The effects of the organic loading rate (OLR) on the performance and the granular sludge characteristics of an expanded granular sludge bed (EGSB) reactor used for treating real traditional Chinese medicine (TCM) wastewater were investigated. Over 90% of the COD removal by the EGSB reactor was observed at the OLRs of 4 to 13 kg COD/(m(3) day). However, increasing the OLR to 20 kg COD/(m(3) day) by reducing the hydraulic retention time (HRT 6 h) reduced the COD removal efficiency to 78%. The volatile fatty acid (VFA) concentration was 512.22 mg/L, resulting in an accumulation of VFAs, and propionic acid was the main acidification product, accounting for 66.51% of the total VFAs. When the OLR increased from 10 to 20 kg COD/(m(3) day), the average size of the granule sludge decreased from 469 to 258 μm. There was an obvious reduction in the concentration of Ca(2+) and Mg(2+) in the granular sludge. The visible humic acid-like peak was identified in the three-dimensional excitation-emission matrix (EEM) fluorescence spectra of the soluble microbial products (SMPs). The fatty acid bond, amide II bond, amide III bond, and C-H bond bending were also observed in the Fourier transform infrared (FTIR) spectra of the SMPs. Methanobacterium formicicum, Methanococcus, and Bacteria populations exhibited significant shifts, and these changes were accompanied by an increase in VFA production. The results indicated that a short HRT and high OLR in the EGSB reactor caused the accumulation of polysaccharides, protein, and VFAs, thereby inhibiting the activity of methanogenic bacteria and causing granular sludge corruption.

Design of a photoswitchable hollow microcapsular drug delivery system by using a supramolecular drug-loading approach.

PubMed

Xiao, Wang; Chen, Wei-Hai; Zhang, Jing; Li, Cao; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2011-11-24

In this study, photoswitchable microcapsules were fabricated based on host-guest interactions between α-cyclodextrin (α-CD) and azobenzene (Azo). Carboxymethyl dextran-graft-α-CD (CMD-g-α-CD) and poly(acrylic acid) N-aminododecane p-azobenzeneaminosuccinic acid (PAA-C(12)-Azo) were assembled layer by layer on CaCO(3) particles. α-CD-rhodamine B (α-CD-RhB), used as a model drug, was loaded on PAA-C(12)-Azo layers by host-guest interaction. After removal of CaCO(3) particles by ethylenediaminetetraacetic acid (EDTA), hollow microcapsules loaded with α-CD-RhB were obtained. Since the interactions between α-CD and Azo were photosensitive, the capsules could be dissociated with the irradiation of UV light, followed by the release of the model drug, α-CD-RhB. Compared with traditional drug-loading approaches such as chemical bonding and physical adsorption, our supramolecular drug-loading system has a facile loading process, ideal bonding strength, and photoswitchable behavior. These photosensitive microcapsules exhibit great potential in biomedical applications. © 2011 American Chemical Society

Effect of H{sub 3}PW{sub 12}O{sub 40} impregnation on Sn-MCM-41 mesoporous molecular sieves and their physico-chemical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nedumaran, D.; Department of Chemistry, RMK Engineering College, Chennai; Pandurangan, A., E-mail: pandurangan_a@yahoo.com

2015-01-15

Graphical abstract: The wide angle XRD shows the well dispersion of HPWA in Sn-MCM-41. It enhances the total acidity of the material. The acidity of the material is correlated with sulfone selectivity. The FT-IR of dibenzothiophene and product shows the formation of sulfone (DBTO{sub 2}). - Highlights: • To enhance the total acidity of Sn-MCM-41 TPA is impregnated. • FT-IR and {sup 31}P MAS NMR confirms the HPWA intact on Sn-MCM-41. • EDAX shows the presence of W and P on Sn-MCM-41. • In ODS formation of sulfone was confirmed by FT-IR and {sup 1}H NMR. • The order ofmore » the catalytic activity of the catalysts are 18HSnM > 28HSnM > 8HSnM. - Abstract: Si-Sn-MCM-41 (Si/Sn = 110) mesoporous molecular sieve was synthesized by hydrothermal sol–gel method using cetyltrimethylammonium bromide (CTAB) as surfactant and SnCl{sub 4}·5H{sub 2}O as a metal source. To generate surface acidity of Si-Sn-MCM-41, 12-tungstophosphoric acid (HPWA) is impregnated on it. The acidity of HPWA loading on Sn-MCM-41 was investigated by temperature programmed desorption of NH{sub 3}. The diffused reflectance spectra of ultraviolet radiation, Raman spectra, FT-IR, {sup 29}Si-MAS NMR and {sup 31}P-MAS NMR techniques revealed the intact of α-Keggin anions on Sn-MCM-41. The wide angle XRD results showed that the HPWA is well dispersed on the support. The total acidity was enhanced with increase in loading of H{sub 3}PW{sub 12}O{sub 40}. The catalytic activity was examined in desulfurization of dibenzothiophene in vapor phase system. Among the catalysts 18% HPWA loaded Sn-MCM-41 showed good catalytic activity in desulfurization at 325 °C. The HPWA/Sn-MCM-41 are a suitable solid acid catalyst for converting organic sulfur into insoluble sulfone.« less

The Molecular Basis for Load-Induced Skeletal Muscle Hypertrophy

PubMed Central

Marcotte, George R.; West, Daniel W.D.; Baar, Keith

2016-01-01

In a mature (weight neutral) animal, an increase in muscle mass only occurs when the muscle is loaded sufficiently to cause an increase in myofibrillar protein balance. A tight relationship between muscle hypertrophy, acute increases in protein balance, and the activity of the mechanistic target of rapamycin complex 1 (mTORC1) was demonstrated 15 years ago. Since then, our understanding of the signals that regulate load-induced hypertrophy has evolved considerably. For example, we now know that mechanical load activates mTORC1 in the same way as growth factors, by moving TSC2 (a primary inhibitor of mTORC1) away from its target (the mTORC activator) Rheb. However, the kinase that phosphorylates and moves TSC2 is different in the two processes. Similarly, we have learned that a distinct pathway exists whereby amino acids activate mTORC1 by moving it to Rheb. While mTORC1 remains at the forefront of load-induced hypertrophy, the importance of other pathways that regulate muscle mass are becoming clearer. Myostatin, is best known for its control of developmental muscle size. However, new mechanisms to explain how loading regulates this process are suggesting that it could play an important role in hypertrophic muscle growth as well. Lastly, new mechanisms are highlighted for how β2 receptor agonists could be involved in load-induced muscle growth and why these agents are being developed as non-exercise-based therapies for muscle atrophy. Overall, the results highlight how studying the mechanism of load-induced skeletal muscle mass is leading the development of pharmaceutical interventions to promote muscle growth in those unwilling or unable to perform resistance exercise. PMID:25359125

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

PubMed Central

Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

2014-01-01

A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. PMID:24855351

Resin-dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding. Part II: Effects of mechanical cycling load on microtensile bond strengths.

PubMed

Sauro, Salvatore; Toledano, Manuel; Aguilera, Fatima Sánchez; Mannocci, Francesco; Pashley, David H; Tay, Franklin R; Watson, Timothy F; Osorio, Raquel

2011-06-01

To compare microtensile bond strengths (MTBS) subsequent to load cycling of resin bonded acid-etched or EDTA-treated dentin using a modified ethanol wet-bonding technique. Flat dentin surfaces were obtained from extracted human molars and conditioned using 37% H(3)PO(4) (PA) (15s) or 0.1M EDTA (60s). Five experimental adhesives and one commercial bonding agent were applied to the dentin and light-cured. Solvated experimental resins (50% ethanol/50% comonomers) were used as primers and their respective neat resins were used as the adhesives. The resin-bonded teeth were stored in distilled water (24h) or submitted to 5000 loading cycles of 90N. The bonded teeth were then sectioned in beams for MTBS. Modes of failure were examined by scanning electron microscopy. The most hydrophobic resin 1 gave the lowest bond strength values to both acid and EDTA-treated dentin. The hydrophobic resin 2 applied to EDTA-treated dentin showed lower bond strengths after cycling load but this did not occur when it was bonded to PA-etched dentin. Resins 3 and 4, which contained hydrophilic monomers, gave higher bond strengths to both EDTA-treated or acid-etched dentin and showed no significant difference after load cycling. The most hydrophilic resin 5 showed no significant difference in bond strengths after cycling loading when bonded to EDTA or phosphoric acid treated dentin but exhibited low bond strengths. The presence of different functional monomers influences the MTBS of the adhesive systems when submitted to cyclic loads. Adhesives containing hydrophilic comonomers are not affected by cycling load challenge especially when applied on EDTA-treated dentin followed by ethanol wet bonding. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Improvement of drug loading onto ion exchange resin by cyclodextrin inclusion complex.

PubMed

Samprasit, Wipada; Rojanarata, Theerasak; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Sila-on, Warisada; Opanasopit, Praneet

2013-11-01

Ion exchange resins have ability to exchange their counter ions for ionized drug in the surrounding medium, yielding "drug resin complex." Cyclodextrin can be applied for enhancement of drug solubility and stability. Cyclodextrin inclusion complex of poorly water-soluble NSAIDs, i.e. meloxicam and piroxicam, was characterized and its novel application for improving drug loading onto an anionic exchange resin, i.e. Dowex® 1×2, was investigated. β-Cyclodextrin (β-CD) and hydroxypropyl β-cyclodextrin (HP-β-CD) were used for the preparation of inclusion complex with drugs in solution state at various pH. The inclusion complex was characterized by phase solubility, continuous variation, spectroscopic and electrochemistry methods. Then, the drug with and without cyclodextrin were equilibrated with resin at 1:1 and 1:2 weight ratio of drug and resin. Solubility of the drugs was found to increase with increasing cyclodextrin concentration and pH. The increased solubility was explained predominantly due to the formation of inclusion complex at low pH and the increased ionization of drug at high pH. According to characterization studies, the inclusion complex was successfully formed with a 1:1 stoichiometry. The presence of cyclodextrin in the loading solution resulted in the improvement of drug loading onto resin. Enhancing drug loading onto ion-exchange resin via the formation of cyclodextrin inclusion complex is usable in the development of ion-exchange based drug delivery systems, which will beneficially reduce the use of harmful acidic or basic and organic chemicals.

The ddY mouse: a model of postprandial hypertriglyceridemia in response to dietary fat

PubMed Central

Yamazaki, Tomomi; Kishimoto, Kyoko; Ezaki, Osamu

2012-01-01

Postprandial hyperlipidemia (lipemia) is a risk factor for atherosclerosis. However, mouse models of postprandial hyperlipidemia have not been reported. Here, we report that ddY mice display marked postprandial hypertriglyceridemia in response to dietary fat. In ddY mice, the fasting serum total triacylglyceride (TG) concentration was 134 mg/dl, which increased to 571 mg/dl after an intragastric safflower oil load (0.4 ml/mouse). In C57BL/6J mice, these concentrations were 57 and 106 mg/dl, respectively. By lipoprotein analysis, ddY mice showed increases in chylomicron- and VLDL-sized TG fractions (remnants and VLDL) after fat load. In C57BL/6J mice, post-heparin plasma LPL activity after fat load was increased 4.8-fold relative to fasting. However, in ddY mice, the increase of LPL activity after fat load was very small (1.2-fold) and not significant. High fat feeding for 10 weeks led to obesity in ddY mice. A difference in LPL amino acid composition between C57BL/6J and ddY mice was detected but was deemed unlikely to cause hypertriglyceridemia because hypertriglyceridemia was not evident in other strains harboring the ddY-type LPL sequence. These findings indicate that postprandial hypertriglyceridemia in ddY mice is induced by decreased LPL activity after fat load and is associated with obesity induced by a high-fat diet. PMID:22735545

Chitosan-based nanocomplexes for simultaneous loading, burst reduction and controlled release of doxorubicin and 5-fluorouracil.

PubMed

Di Martino, Antonio; Kucharczyk, Pavel; Capakova, Zdenka; Humpolicek, Petr; Sedlarik, Vladimir

2017-09-01

In this work, nanocomplexes based on chitosan grafted by carboxy-modified polylactic acid (SPLA) were prepared with the aim of loading simultaneously two anticancer drugs - doxorubicin and 5-fluorouracil, as well as to control their release, reduce the initial burst and boost cytotoxicity. The SPLA was prepared by a polycondensation reaction, using pentetic acid as the core molecule, and linked to the chitosan backbone through a coupling reaction. Nanocomplexes loaded with both drugs were formulated by the polyelectrolyte complexation method. The structure of the SPLA was characterized by 1 H NMR, while the product CS-SPLA was analyzed by FTIR-ATR to prove the occurrence of the reaction. Results showed that the diameters and ζ-potential of the nanocomplexes fall in the range 120-200nm and 20-37mV, respectively. SEM and TEM analysis confirmed the spherical shape and dimensions of the nanocomplexes. The presence of hydrophobic side chain SPLA did not influence the encapsulation efficiency of the drugs but strongly reduced the initial burst and prolonged release over time compared to unmodified chitosan. MS analysis showed that no degradation or interactions between the drugs and carrier were exhibited after loading or 24h of release had taken place, confirming the protective role of the nanocomplexes. In vitro tests demonstrated an increase in the cytotoxicity of the drugs when loaded in the prepared carriers. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

High Capacity Na+/H+ Exchange Activity in Mineralizing Osteoblasts

PubMed Central

Liu, Li; Schlesinger, Paul H.; Slack, Nicole M.; Friedman, Peter A.; Blair, Harry C.

2015-01-01

Osteoblasts synthesize bone in polarized groups of cells sealed by tight junctions. Large amounts of acid are produced as bone mineral is precipitated. We addressed the mechanism by which cells manage this acid load by measuring intracellular pH (pHi) in non-transformed osteoblasts in response to weak acid or bicarbonate loading. Basal pHi in mineralizing osteoblasts was ∼7.3 and decreased by ∼ 1.4 units upon replacing extracellular Na+ with N-methyl-d-glucamine. Loading with 40 mM acetic or propionic acids, in normal extracellular Na+, caused only mild cytosolic acidification. In contrast, in Na+-free solutions, weak acids reduced pHi dramatically. After Na+ reintroduction, pHi recovered rapidly, in keeping with Na+/H+exchanger (NHE) activity. Sodium-dependent pHi recovery from weak acid loading was inhibited by amiloride with the Ki consistent with NHEs. NHE1 and NHE6 were expressed strongly, and expression was upregulated highly, by mineralization, in human osteoblasts. Antibody labeling of mouse bone showed NHE1 on basolateral surfaces of all osteoblasts. NHE6 occurred on basolateral surfaces of osteoblasts mainly in areas of mineralization. Conversely, elevated HCO3- alkalinized osteoblasts, and pH recovered in medium containing CI-, with or without Na+, in keeping with Na+-independent CI-/HCO3- exchange. The exchanger AE2 also occurred on the basolateral surface of osteoblasts, consistent with CI-/HCO3- exchange for elimination of metabolic carbonate. Overexpression of NHE6 or knockdown of NHE1 in MG63 human osteosarcoma cells confirmed roles of NHE1 and NHE6 in maintaining pHi. We conclude that in mineralizing osteoblasts, slightly basic basal pHi is maintained, and external acid load is dissipated, by high-capacity Na+/H+ exchange via NHE1 and NHE6. PMID:21413028

Functional and unmodified MWNTs for delivery of the water-insoluble drug Carvedilol - A drug-loading mechanism

NASA Astrophysics Data System (ADS)

Li, Yuting; Wang, Tianyi; Wang, Jing; Jiang, Tongying; Cheng, Gang; Wang, Siling

2011-04-01

The purpose of this study was to develop carboxyl multi-wall carbon nanotubes (MWNTs) and unmodified MWNTs loaded with a poorly water-soluble drug, intended to improve the drug loading capacity, dissolubility and study the drug-loading mechanism. MWNTs were modified with a carboxyl group through the acid treatment. MWNTs as well as the resulting functionalized MWNTs were investigated as scaffold for loading the model drug, Carvedilol (CAR), using three different methods (the fusion method, the incipient wetness impregnation method, and the solvent method). The effects of different pore size, specific surface area and physical state were systematically studied using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transformation infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), nitrogen adsorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The functional MWNTs allowed a higher drug loading than the unmodified preparations. The methods used to load the drug had a marked effect on the drug-loading, dissolution, and physical state of the drug as well as its distribution. In addition, the solubility of the drug was increased when carried by both MWNTs and functional MWNTs, and this might help to improve the bioavailability.

Resveratrol-loaded glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles: Preparation, characterization, and targeting effect on liver tumors.

PubMed

Wu, Mingfang; Lian, Bolin; Deng, Yiping; Feng, Ziqi; Zhong, Chen; Wu, Weiwei; Huang, Yannian; Wang, Lingling; Zu, Chang; Zhao, Xiuhua

2017-08-01

In this study, glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles were prepared to establish a tumor targeting nano-sized drug delivery system. Glycyrrhizic acid was coupled to human serum albumin, and resveratrol was encapsulated in glycyrrhizic acid-conjugated human serum albumin by high-pressure homogenization emulsification. The average particle size of sample nanoparticles prepared under the optimal conditions was 108.1 ± 5.3 nm with a polydispersity index (PDI) of 0.001, and the amount of glycyrrhizic acid coupled with human serum albumin was 112.56 µg/mg. The drug encapsulation efficiency and drug loading efficiency were 83.6 and 11.5%, respectively. The glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles were characterized through laser light scattering, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analyses, and gas chromatography. The characterization results showed that resveratrol in glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles existed in amorphous state and the residual amounts of chloroform and methanol in nanoparticles were separately less than the international conference on harmonization (ICH) limit. The in vitro drug-release study showed that the nanoparticles released the drug slowly and continuously. The inhibitory rate of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide method. The IC50 values of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles and resveratrol were 62.5 and 95.5 µg/ml, respectively. The target ability of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles for HepG2 cells was evaluated using fluorescence-modified albumin techniques. The uptake rate of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles was higher than that of pure resveratrol and increased with increased nanoparticles concentration. The in vivo body distribution of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles labeled with the near-infrared fluorophore Cy5 was monitored in H22 tumor-bearing mice through near-infrared fluorescence imaging systems. Glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles exhibited effective target orientation to liver tumor and sustained-release property.

An experiment on the attrition of acid demineralized dentine in vitro.

PubMed

Li, H; Liu, M C; Deng, M; Moazzez, R; Bartlett, D W

2011-03-01

A laboratory investigation was designed to test the hypothesis that acids increase the rate of wear caused by attrition on dentine. Dentine sections from 10 teeth were polished, cleaned in an ultrasonic bath and divided into 8 equally sized areas. The occlusal tip of a tooth, placed vertically in a wear machine and loaded at 150 N, was moved against each dentine section for 5000 return strokes with artificial saliva acting as a lubricant. Each dentine section was divided into 8 sections and half randomly immersed in a 1% citric acid solution (pH 2.3) for 20 minutes. The wear regime produced 8 wear scars in total per dentine sample. The volume of each wear scar was measured using a contacting digitizing profilometer. A total of 80 wear scars were produced with 40 treated with acid and 40 acting as controls. The mean for wear volume of the dentine scars with acid was 4.84 μm(3) (1.38) and for the non-acid surface 2.95 μm(3) (0.86). This difference was statistically significant (p < 0.05). These results support the hypothesis that acids increase the rate of wear caused by attrition on dentine. © 2011 Australian Dental Association.

Acid-triggered core cross-linked nanomicelles for targeted drug delivery and magnetic resonance imaging in liver cancer cells

PubMed Central

Li, Xian; Li, Hao; Yi, Wei; Chen, Jianyu; Liang, Biling

2013-01-01

Purpose To research the acid-triggered core cross-linked folate-poly(ethylene glycol)-b-poly[N-(N′,N′-diisopropylaminoethyl) glutamine] (folated-PEG-P[GA-DIP]) amphiphilic block copolymer for targeted drug delivery and magnetic resonance imaging (MRI) in liver cancer cells. Methods As an appropriate receptor of protons, the N,N-diisopropyl tertiary amine group (DIP) was chosen to conjugate with the side carboxyl groups of poly(ethylene glycol)-b-poly (L-glutamic acid) to obtain PEG-P(GA-DIP) amphiphilic block copolymers. By ultrasonic emulsification, PEG-P(GA-DIP) could be self-assembled to form nanosized micelles loading doxorubicin (DOX) and superparamagnetic iron oxide nanoparticles (SPIONs) in aqueous solution. When PEG-P(GA-DIP) nanomicelles were combined with folic acid, the targeted effect of folated-PEG-P(GA-DIP) nanomicelles was evident in the fluorescence and MRI results. Results To further increase the loading efficiency and the cell-uptake of encapsulated drugs (DOX and SPIONs), DIP (pKa≈6.3) groups were linked with ~50% of the side carboxyl groups of poly(L-glutamic acid) (PGA), to generate the core cross-linking under neutral or weakly acidic conditions. Under the acidic condition (eg, endosome/lysosome), the carboxyl groups were neutralized to facilitate disassembly of the P(GA-DIP) blocks’ cross-linking, for duly accelerating the encapsulated drug release. Combined with the tumor-targeting effect of folic acid, specific drug delivery to the liver cancer cells and MRI diagnosis of these cells were greatly enhanced. Conclusion Acid-triggered and folate-decorated nanomicelles encapsulating SPIONs and DOX, facilitate the targeted MRI diagnosis and therapeutic effects in tumors. PMID:23976852

Free radicals mediate postshock contractile impairment in cardiomyocytes.

PubMed

Tsai, Min-Shan; Sun, Shijie; Tang, Wanchun; Ristagno, Giuseppe; Chen, Wen-Jone; Weil, Max Harry

2008-12-01

Previous studies demonstrated myocardial dysfunction after electrical shock and indicated it may be related to free radicals. Whether the free radicals are generated after electrical shock has not been documented at the cellular level. This study was to investigate whether electrical shock generates intracellular free radicals inside cardiomyocytes and to evaluate whether reducing intracellular free radicals by pretreatment of ascorbic acid would reduce the contractile dysfunction after electrical shock. Randomized prospective animal study. University affiliated research laboratory. Sprague-Dawley rats. Cardiomyocytes isolated from adult male rats were divided into four groups: (1) electrical shock alone; (2) electrical shock pretreated with ascorbic acid; (3) pretreated with ascorbic acid alone; and (4) control. Ascorbic acid (0.2 mM) was administrated in the perfusate of the ascorbic acid + electrical shock and ascorbic acid groups. A 2-J electrical shock was delivered to the electrical shock and ascorbic acid + electrical shock groups. DCFH-DA-loaded cardiomyocytes showed increased intracellular free radicals after electrical shock. The contractions and Ca2+ transients were recorded optically with fura-2 loading. Within 4 mins after electrical shock in the electrical shock group, the length shortening decreased from 8.4% +/- 2.5% to 5.6% +/- 3.4% (p = 0.000) and the Ca2+ transient decreased from 1.15 +/- 0.13 au to 1.08 +/- 0.1 au (p = 0.038). Compared with control, a significant difference in length shortening (p = 0.001) but not Ca2+ transient (p = 0.052) was noted. In the presence of ascorbic acid, electrical shock did not affect length shortening and Ca2+ transient. Electrical shock generates free radicals inside the cardiomyocyte, and causes contractile impairment and associated decrease of Ca transient. Administering ascorbic acid may improve such damage by eliminating free radicals.

Budesonide nanocrystal-loaded hyaluronic acid microparticles for inhalation: In vitro and in vivo evaluation.

PubMed

Liu, Tingting; Han, Meihua; Tian, Fang; Cun, Dongmei; Rantanen, Jukka; Yang, Mingshi

2018-02-01

Most inhaled pharmaceutical formulations on the market are intended to exert immediate pharmacological action, even although inhaled sustained-release formulations can be needed to reduce the frequency of dosing. The purpose of this study was to investigate the pulmonary retention and pharmacokinetics of a poorly water-soluble drug after loading its nanocrystal form into inhalable mucoadhesive microparticles composed of hyaluronic acid. It was intended to prolong the pharmacological effect without compromising the dissolution rate of the poorly water-soluble drug. In this study, budesonide, a corticosteroid anti-inflammatory drug, was used as a model poorly water-soluble drug. Submicron budesonide particles were prepared by wet ball milling, and subsequently loaded into hyaluronic acid microparticles by the spray drying process. The ball-milled budesonide particles and the spray-dried microparticles were characterized using dynamic light scattering (DLS), laser diffraction, Scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). Selected formulations were evaluated in terms of their dissolution/release rate, aerosol performance, muco-adhesion and pharmacokinetics in rats. As shown by XRD and DSC analysis, the nanonized budesonide particles in this study were mainly in crystalline form. The dissolution/release study showed that the in vitro release of budesonide from the microparticles was not significantly sustained compared with the dissolution rate of budesonide nanocrystals (BUD-NC). However, the budesonide in the microparticles exhibited prolonged retention on the surface of porcine tracheal tube owing to the muco-adhesion ability of hyaluronic acid. After intratracheal administration to rats, the BUD-NC exhibited a similar pharmacokinetic profile to that of budesonide solution via i.v. injection. In contrast, budesonide loaded in the mucoadhesive microparticles exhibited a significantly prolonged T max and increased bioavailability with the animal model. This study demonstrated that inhaled microparticles composed of hyaluronic acid could produce sustained budesonide pharmacological effects. This can be attributed to the mucoadhesion of the polymer that overcame the mucociliary clearance and, consequently, prolonged the retention of the active substance in the lung without necessarily reducing the in vitro dissolution rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solid lipid nanoparticles for delivery of Calendula officinalis extract.

PubMed

Arana, Lide; Salado, Clarisa; Vega, Sandra; Aizpurua-Olaizola, Oier; de la Arada, Igor; Suarez, Tatiana; Usobiaga, Aresatz; Arrondo, José Luis R; Alonso, Alicia; Goñi, Félix M; Alkorta, Itziar

2015-11-01

Solid lipid nanoparticles (SLN) composed of long-chain fatty acids (palmitic acid, stearic acid or arachidic acid), Epikuron 200 (purified phosphatidylcholine), and bile salts (cholate, taurocholate or taurodeoxycholate) have been prepared by dilution of a microemulsion. A total of five different systems were prepared, and characterized by photon correlation spectroscopy, transmission electron microscopy, differential scanning calorimetry, and infrared spectroscopy. The SLN formulation showing optimal properties (lowest size and polydispersity index and highest zeta potential) was obtained with stearic acid and taurodeoxycholate as cosurfactant. This formulation was loaded with Calendula officinalis extract, a natural compound used on ophthalmic formulations given its anti-inflammatory, emollient, and wound repairing activity. Calendula-loaded SLN preparations were characterized in order to determine loading capacity and entrapment efficiency. In vitro cytotoxicity and wound healing efficacy of Calendula-loaded SLN compared to that of a free plant extract were evaluated on a conjunctival epithelium cell line WKD. Our results suggest that this SLN formulation is a safe and solvent-free Calendula extract delivery system which could provide a controlled therapeutic alternative for reducing disease-related symptoms and improving epithelium repair in ocular surface. Copyright © 2015 Elsevier B.V. All rights reserved.

Developing Critical Loads of acidity for streams in the Great Smoky Mountains National Park, using PnET-BGC model

NASA Astrophysics Data System (ADS)

Fakhraei, H.

2015-12-01

Acid deposition has impaired acid-sensitive streams and reduced aquatic biotic integrity in Great Smoky Mountains National Park (GRSM) by decreasing pH and acid neutralizing capacity (ANC). Twelve streams in GRSM are listed by the state of Tennessee as impaired due to low stream pH (pH<6.0) under Section 303(d) of the Clean Water Act. A dynamic biogeochemical model, PnET-BGC, was used to evaluate past, current and potential future changes in soil and water chemistry of watersheds of GRSM in response to changes in acid deposition. Calibrating 30 stream-watersheds in GRSM (including 12 listed impaired streams) to the long-term stream chemistry observations, the model was parameterized for the Park. The calibrated model was used to evaluate the level of atmospheric deposition above which harmful effects occur, known as "critical loads", for individual study watersheds. Estimated critical loads and exceedances (levels of deposition above the critical load) of atmospheric sulfur and nitrogen deposition were depicted through geographic information system maps. Accuracy of model simulations in the presence of uncertainties in the estimated model parameters and inputs was assessed using three uncertainty and sensitivity techniques.

Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

NASA Astrophysics Data System (ADS)

Jia, Wenbao; He, Yanquan; Ling, Yongsheng; Hei, Daqian; Shan, Qing; Zhang, Yan; Li, Jiatong

2015-04-01

The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L-1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the •OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while •H and eaq- played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation.

Very Low-Protein Diet (VLPD) Reduces Metabolic Acidosis in Subjects with Chronic Kidney Disease: The “Nutritional Light Signal” of the Renal Acid Load

PubMed Central

Di Iorio, Biagio Raffaele; Di Micco, Lucia; Marzocco, Stefania; De Simone, Emanuele; De Blasio, Antonietta; Sirico, Maria Luisa; Nardone, Luca

2017-01-01

Background: Metabolic acidosis is a common complication of chronic kidney disease; current guidelines recommend treatment with alkali if bicarbonate levels are lower than 22 mMol/L. In fact, recent studies have shown that an early administration of alkali reduces progression of CKD. The aim of the study is to evaluate the effect of fruit and vegetables to reduce the acid load in CKD. Methods: We conducted a case-control study in 146 patients who received sodium bicarbonate. Of these, 54 patients assumed very low-protein diet (VLPD) and 92 were controls (ratio 1:2). We calculated every three months the potential renal acid load (PRAL) and the net endogenous acid production (NEAP), inversely correlated with serum bicarbonate levels and representing the non-volatile acid load derived from nutrition. Un-paired T-test and Chi-square test were used to assess differences between study groups at baseline and study completion. Two-tailed probability values ≤0.05 were considered statistically significant. Results: At baseline, there were no statistical differences between the two groups regarding systolic blood pressure (SBP), diastolic blood pressure (DBP), protein and phosphate intake, urinary sodium, potassium, phosphate and urea nitrogen, NEAP, and PRAL. VLPD patients showed at 6 and 12 months a significant reduction of SBP (p < 0.0001), DBP (p < 0.001), plasma urea (p < 0.0001) protein intake (p < 0.0001), calcemia (p < 0.0001), phosphatemia (p < 0.0001), phosphate intake (p < 0.0001), urinary sodium (p < 0.0001), urinary potassium (p < 0.002), and urinary phosphate (p < 0.0001). NEAP and PRAL were significantly reduced in VLPD during follow-up. Conclusion: VLPD reduces intake of acids; nutritional therapy of CKD, that has always taken into consideration a lower protein, salt, and phosphate intake, should be adopted to correct metabolic acidosis, an important target in the treatment of CKD patients. We provide useful indications regarding acid load of food and drinks—the “acid load dietary traffic light”. PMID:28106712

Antiplatelet effects of protopine isolated from Corydalis tubers.

PubMed

Ko, F N; Wu, T S; Lu, S T; Wu, Y C; Huang, T F; Teng, C M

1989-10-15

Protopine inhibited the aggregation and ATP release of rabbit platelets induced by ADP, arachidonic acid, PAF, collagen and ionophore A23187. Although the platelet aggregation caused by thrombin was not inhibited by protopine (100 micrograms/ml), the release reaction was partially suppressed. In rabbit platelet-rich plasma, protopine also inhibited the platelet aggregation caused by ADP, arachidonic acid, PAF and collagen. The thromboxane B2 formation of washed platelets caused by arachidonic acid, collagen, ionophore A23187 and thrombin was suppressed by protopine. Protopine inhibited the intracellular calcium increase caused by arachidonic acid in quin-2/AM loaded rabbit platelets. In the presence of indomethacin, the intracellular calcium increase caused by collagen and PAF was completely suppressed by protopine, and the intracellular calcium increase caused by thrombin was partially inhibited. The phosphoinositides breakdown caused by collagen and PAF was inhibited by protopine, but that by thrombin was not affected significantly. Protopine did not cause the elevation of cyclic AMP level of platelets. It is concluded that the antiplatelet effects of protopine is due to inhibition on thromboxane formation and phosphoinositides breakdown and then lead to the decrease of intracellular calcium concentration.

Achieving the Promise of Therapeutic Extracellular Vesicles: The Devil is in Details of Therapeutic Loading.

PubMed

Sutaria, Dhruvitkumar S; Badawi, Mohamed; Phelps, Mitch A; Schmittgen, Thomas D

2017-05-01

Extracellular vesicles (EVs) represent a class of cell secreted organelles which naturally contain biomolecular cargo such as miRNA, mRNA and proteins. EVs mediate intercellular communication, enabling the transfer of functional nucleic acids from the cell of origin to the recipient cells. In addition, EVs make an attractive delivery vehicle for therapeutics owing to their increased stability in circulation, biocompatibility, low immunogenicity and toxicity profiles. EVs can also be engineered to display targeting moieties on their surfaces which enables targeting to desired tissues, organs or cells. While much has been learned on the role of EVs as cell communicators, the field of therapeutic EV application is currently under development. Critical to the future success of EV delivery system is the description of methods by which therapeutics can be successfully and efficiently loaded within the EVs. Two methods of loading of EVs with therapeutic cargo exist, endogenous and exogenous loading. We have therefore focused this review on describing the various published approaches for loading EVs with therapeutics.

Effect of alginate composition on profile release and characteristics of chitosan-alginate microparticles loaded with mangosteen extract

NASA Astrophysics Data System (ADS)

Mulia, Kamarza; Halimah, Nur; Krisanti, Elsa

2017-03-01

Preparation of mangostin-loaded chitosan-alginate microparticles, chemical and physical characterization of the particles, and mangostin release profiles, are described herein. Mangostin rich fraction was obtained from Garcinia mangostana L. pericarp by extraction followed by fractionation. Mangostin-loaded chitosan-alginate microparticles were prepared by ionic gelation method using tripolyphosphate as the linking agent and various concentration of alginate. Mangostin was effectively loaded in all microparticle formulations, resulting in ˜97% encapsulation efficiencies. The loading of mangostin and the in-vitro release profiles in simulated gastrointestinal fluids were affected by the chitosan to alginate ratios used in the preparation of the microparticles. Increased alginate concentration resulted in lowered release of mangostin from microparticles immersed in simulated gastric fluid (pH 1.2) up to two hours. Low release of mangostin in acidic fluid but high release in simulated colon fluid, indicated that the chitosan-alginate microparticles are prospective carrier for extended release of active compound in gastrointestinal system.

Corrosion in MDEA sour gas treating plants: Correlation between laboratory testing and field experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bich, N.N.; Vacha, F.; Schubert, R.

1996-08-01

Corrosion in MDEA sour gas treating systems operating in severely loaded conditions is investigated using both laboratory data and actual gas plant experience. Effects of acid gas loading, flow turbulence, solution quality, temperature, etc. on corrosion are being studied. Preliminary results indicated severe corrosion of several mm/y would occur if acid gas loading, circulation rate and level of suspended solids are all high. A mitigation strategy based on operating envelopes is formulated.

Intake of green tea inhibited increase of salivary chromogranin A after mental task stress loads

PubMed Central

2014-01-01

Background Green tea has become renowned for its health benefits. In this study, we investigated the anti-stress effect of two kinds of green tea against a mental stress task load. Methods Warm water, ordinary green tea (Sagara), and shaded white tea, which contains more amino acid components than Sagara, were used as test samples in a randomized cross-over design study. Eighteen students (nine male and nine female) participated in three experimental trials on different days at intervals of seven days. Saliva was collected before beverage intake and after performing the mental stress load tasks. Concentration of chromogranin A (CgA) in the saliva was used as an index of autonomic nervous system activity. Results CgA level increased after the mental tasks, but intake of green tea inhibited this increase; the anti-stress effect was even greater after consumption of shaded white tea. Intake of shaded white tea also lowered Total Mood Disturbance (TMD) score on the Profile of Mood States (POMS); subjects in this condition tended to perform more calculations in the arithmetic task than those in the warm water treatment condition. Conclusions Salivary CgA concentration levels increased after mental stress load tasks, but ingestion of green tea inhibited this increase. This anti-stress effect was larger after the consumption of shaded white tea than after Sagara. Shaded white tea intake also lowered TMD score (POMS) and tended to improve performance on an arithmetic task compared to warm water, suggesting that shaded white tea might also improve mood during and after mental stress load. PMID:25034805

Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

Treesearch

Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

2014-01-01

Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

Quantitative analysis of ruminal bacterial populations involved in lipid metabolism in dairy cows fed different vegetable oils.

PubMed

Vargas-Bello-Pérez, E; Cancino-Padilla, N; Romero, J; Garnsworthy, P C

2016-11-01

Vegetable oils are used to increase energy density of dairy cow diets, although they can provoke changes in rumen bacteria populations and have repercussions on the biohydrogenation process. The aim of this study was to evaluate the effect of two sources of dietary lipids: soybean oil (SO, an unsaturated source) and hydrogenated palm oil (HPO, a saturated source) on bacterial populations and the fatty acid profile of ruminal digesta. Three non-lactating Holstein cows fitted with ruminal cannulae were used in a 3×3 Latin square design with three periods consisting of 21 days. Dietary treatments consisted of a basal diet (Control, no fat supplement) and the basal diet supplemented with SO (2.7% of dry matter (DM)) or HPO (2.7% of DM). Ruminal digesta pH, NH3-N and volatile fatty acids were not affected by dietary treatments. Compared with control and HPO, total bacteria measured as copies of 16S ribosomal DNA/ml by quantitative PCR was decreased (P<0.05) by SO. Fibrobacter succinogenes, Butyrivibrio proteoclasticus and Anaerovibrio lipolytica loads were not affected by dietary treatments. In contrast, compared with control, load of Prevotella bryantii was increased (P<0.05) with HPO diet. Compared with control and SO, HPO decreased (P<0.05) C18:2 cis n-6 in ruminal digesta. Contents of C15:0 iso, C18:11 trans-11 and C18:2 cis-9, trans-11 were increased (P<0.05) in ruminal digesta by SO compared with control and HPO. In conclusion, supplementation of SO or HPO do not affect ruminal fermentation parameters, whereas HPO can increase load of ruminal P. bryantii. Also, results observed in our targeted bacteria may have depended on the saturation degree of dietary oils.

Pd-loaded carbon felt as the cathode for selective dechlorination of 2,4-dichlorophenoxyacetic acid in aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsyganok, A.I.; Yamanaka, Ichiro; Otsuka, Kiyoshi

1998-11-01

Electrocatalytic reductive dehalogenation of 2,4-dichlorophenoxyacetic acid (2,4-D) to phenoxyacetic acid in aqueous solution containing MeOH, trifluoroacetic acid, and tetraalkylammonium salt was studied. A Teflon-made two-compartment flow-through cell with a permeable carbon felt cathode and a platinum foil anode was employed. Several noble metals were tested as electrocatalysts. Palladium-loaded carbon felt was found to be the most suitable significantly enhanced its electrocatalytic activity toward 2,4-D dechlorination. The reaction was hypothesized to proceed at carbon-palladium interface areas through 4-chlorine cleavage to form 2-chlorophenoxyacetic acid as the main reaction intermediate.

Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate.

PubMed

Hiemstra, Tjisse; Mia, Shamim; Duhaut, Pierre-Benoît; Molleman, Bastiaan

2013-08-20

Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application of biochar, potentially creating Darks Earths or Terra Preta soils. A surface complexation approach has been developed that aims to describe the competitive behavior of natural organic matter (NOM) in soil as well as model systems. Modeling points unexpectedly to a strong change of the molecular conformation of humic acid (HA) with a predominant adsorption in the Stern layer domain at low NOM loading. In soil, mineral oxide surfaces remain efficiently loaded by mineral-protected organic carbon (OC), equivalent with a layer thickness of ≥ ~0.5 nm that represents at least 0.1-1.0% OC, while surface-associated OC may be even three times higher. In natural systems, surface complexation modeling should account for this pervasive NOM coverage. With our charge distribution model for NOM (NOM-CD), the pH-dependent oxyanion competition of the organo-mineral oxide fraction can be described. For pyrogenic HA, a more than 10-fold increase in dissolved phosphate is predicted at long-term applications of biochar or black carbon.

Blood and muscle metabolic responses to draught work of varying intensity and duration in horses.

PubMed

Gottlieb, M; Essén-Gustavsson, B; Skoglund-Wallberg, H

1989-07-01

Three standardbred trotters performed treadmill exercise at a velocity of 2 m s-1 with a draught load of both 34 kiloponds (kp) (test 1) and 80 kp (test 2), and also at 7 m s-1 with 34 kp (test 3). The heart rate increased to average values of 111 (+/- 5), 157 (+/- 10) and 197 (+/- 7) beats min-1 in tests 1, 2, and 3, respectively. Plasma free fatty acids increased only during tests 1 and 2. Blood lactate and muscle glucose-6-phosphate and lactate concentrations were low after tests 1 and 2, but high after test 3, where also muscle glycogen utilisation was greatest. Muscle creatine phosphate and adenosine triphosphate concentrations decreased after test 3 only. The study indicates that oxidative metabolism is most important for energy supply in muscles when exercise is performed with draught loads of both 34 and 80 kp at a low velocity. Glycogenolysis with lactate accumulation and phosphagen breakdown becomes much more important when, with a draught load of 34 kp, the velocity of exercise increases.

Therapeutic Efficacy of an ω-3-Fatty Acid-Containing 17-β Estradiol Nano-Delivery System against Experimental Atherosclerosis

PubMed Central

Deshpande, Dipti; Kethireddy, Sravani; Janero, David R.; Amiji, Mansoor M.

2016-01-01

Atherosclerosis and its consequences remain prevalent clinical challenges throughout the world. Initiation and progression of atherosclerosis involves a complex, dynamic interplay among inflammation, hyperlipidemia, and endothelial dysfunction. A multicomponent treatment approach targeted for delivery within diseased vessels could prove beneficial in treating atherosclerosis. This study was undertaken to evaluate the multimodal effects of a novel ω-3-fatty acid-rich, 17-β-estradiol (17-βE)-loaded, CREKA-peptide-modified nanoemulsion system on experimental atherosclerosis. In vitro treatment of cultured human aortic endothelial cells (ECs) with the 17-βE-loaded, CREKA-peptide-modified nanoemulsion system increased cellular nitrate/nitrite, indicating improved nitric oxide formation. In vivo, systemic administration of this nanoemulsion system to apolipoprotein-E knock out (ApoE-/-) mice fed a high-fat diet significantly improved multiple parameters related to the etiology and development of occlusive atherosclerotic vasculopathy: lesion area, circulating plasma lipid levels, and expression of aortic-wall inflammatory markers. These salutary effects were attributed selectively to the 17-βE and/or ω-3 polyunsaturated fatty acid components of the nano-delivery system. At therapeutic doses, the 17-βE-loaded, CREKA-peptide modified nanoemulsion system appeared to be biocompatible in that it elicited no apparent adverse/toxic effects, as indexed by body weight, plasma alanine aminotransferase/aspartate aminotransferase levels, and liver and kidney histopathology. The study demonstrates the therapeutic potential of a novel, 17-βE-loaded, CREKA-peptide-modified nanoemulsion system against atherosclerosis in a multimodal fashion by reducing lesion size, lowering the levels of circulating plasma lipids and decreasing the gene expression of inflammatory markers associated with the disease. PMID:26840601

Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid.

PubMed

Keum, Chang-Gu; Noh, Young-Wook; Baek, Jong-Suep; Lim, Ji-Ho; Hwang, Chan-Ju; Na, Young-Guk; Shin, Sang-Chul; Cho, Cheong-Weon

2011-01-01

Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2-5 minutes of sonication time, 70-130 W sonication power, and 5-25 mg drug loading. A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20.83%, 40.07%, and 51.5% of the docetaxel was released in 28 days from nanoparticles containing Poloxamer 188, TPGS, or polyvinyl alcohol, respectively. TPGS and Poloxamer 188 had slower release kinetics than polyvinyl alcohol. It was predicted that there was residual drug remaining on the surface from x-ray photoelectron spectroscopy. Our research shows that the choice of surfactant is important for controlled release of docetaxel.

Comparison of ionic and non-ionic drug release from multi-membrane spherical aerogels.

PubMed

Veronovski, Anja; Knez, Zeljko; Novak, Zoran

2013-09-15

The presented research was oriented towards the preparation of dry biodegradable alginate aerogels with multi-membranes using a multi-step sol-gel process with potential applications as carriers during oral drug delivery. First alginate spherical hydrogels were formed in CaCl2 or BaCl2 solutions by ionic cross-linking. These cores were further immersed into alginate sodium solution, filtered through a sieve, and dropped into the salt solution again. Multi-membrane hydrogels were obtained by repeating the above process. They were further converted into aerogels by supercritical drying. The effect of the number of membranes was investigated regarding the loading and release of the model drugs nicotinic acid and theophylline. Moreover, the efficiencies of Ba(2+) and Ca(2+) metal ions for forming tridimensional networks that retain and extend drug release were also investigated. Nicotinic acid release was prolonged by adding membranes around the core and using Ca(2+) for cross-linking. However, retarded theophylline release was only obtained by using Ba(2+) for cross-linking. Namely, by increasing the number of membranes and BaCl2 concentration drug release became linear versus time in all studied cases. In the case of nicotinic acid loading increased by adding membranes around the core, however, for theophylline the opposite results were obtained due to the different nature of the model drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Drinking water constituents and disease.

PubMed

Rylander, Ragnar

2008-02-01

Several epidemiological investigations over the last 50 y have demonstrated a relation between risk for cardiovascular disease and drinking water hardness or its content of magnesium and calcium. An additional parameter, first suggested in a study from Japan 50 y ago, is the acidity of the water. It is known that acid load influences the reabsorption of calcium and magnesium in the renal tubuli. Intervention studies have shown that acid-base conditions influence the homeostasis of minerals. Data from intervention studies using magnesium, calcium, and hydrogen carbonate are reviewed. It is suggested that the health effects related to drinking water found in some studies may be caused by an increased urinary excretion of minerals induced by acid conditions in the body and that drinking water should contain sufficient amounts of hydrogen carbonate to prevent this effect.

Oxidative stress upregulates zinc uptake activity via Zrt/Irt-like protein 1 (ZIP1) in cultured mouse astrocytes.

PubMed

Furuta, Takahiro; Ohshima, Chiaki; Matsumura, Mayu; Takebayashi, Naoto; Hirota, Emi; Mawaribuchi, Toshiki; Nishida, Kentaro; Nagasawa, Kazuki

2016-04-15

Zinc released from glutamatergic boutons and astrocytes acts as neuro- and glio-transmitters, and thus its extracellular level has to be strictly regulated. We previously revealed that uptake of zinc by astrocytes plays a critical role in its clearance, and zinc transporter Zrt/Irt-like protein 1 (ZIP1) is the molecule responsible for the uptake. However, it is unknown whether or not the functionality of the zinc clearance system is altered under oxidative stress-loaded conditions. Here, we characterized zinc uptake by oxidative stress-loaded astrocytes. Cultured mouse astrocytes were treated with hydrogen peroxide (H2O2) to load oxidative stress. Functional expression of ZIP1 in astrocytes was evaluated by means of (65)Zn uptake, Western blotting and immunocytochemical analysis. Treatment of astrocytes with 0.4mM H2O2 for 24h increased the expression levels of glial fibrillary acidic protein and 4-hydroxynonenal without significant decreases in their viability, indicating that induction of oxidative stress in astrocytes. Under oxidative stress-loaded conditions, astrocytes exhibited increased (65)Zn uptake activity, and the maximum uptake velocity for the uptake was significantly increased compared to that in the control group, while there was no change in the Michaelis constants, which were almost identical to that of mouse ZIP1. In the H2O2-treated astrocytes, the expression levels of ZIP1 were significantly increased in the cellular and plasma membrane fractions. It appears that under oxidative stress-loaded conditions, astrocytes exhibit increased zinc clearance activity and this is due, at least in part, to increased ZIP1 expression. Copyright © 2016 Elsevier Inc. All rights reserved.

Anthropogenically enhanced chemical weathering and carbon evasion in the Yangtze Basin

PubMed Central

Guo, Jingheng; Wang, Fushun; Vogt, Rolf David; Zhang, Yuhang; Liu, Cong-Qiang

2015-01-01

Chemical weathering is a fundamental geochemical process regulating the atmosphere-land-ocean fluxes and earth’s climate. It is under natural conditions driven primarily by weak carbonic acid that originates from atmosphere CO2 or soil respiration. Chemical weathering is therefore assumed as positively coupled with its CO2 consumption in contemporary geochemistry. Strong acids (i.e. sulfuric- and nitric acid) from anthropogenic sources have been found to influence the weathering rate and CO2 consumption, but their integrated effects remain absent in the world largest river basins. By interpreting the water chemistry and overall proton budget in the Yangtze Basin, we found that anthropogenic acidification had enhanced the chemical weathering by 40% during the past three decades, leading to an increase of 30% in solute discharged to the ocean. Moreover, substitution of carbonic acid by strong acids increased inorganic carbon evasion, offsetting 30% of the CO2 consumption by carbonic weathering. Our assessments show that anthropogenic loadings of sulfuric and nitrogen compounds accelerate chemical weathering but lower its CO2 sequestration. These findings have significant relevance to improving our contemporary global biogeochemical budgets. PMID:26150000

Degradation of isobutanal at high loading rates in a compost biofilter.

PubMed

Sercu, Bram; Demeestere, Kristof; Baillieul, Hans; Van Langenhove, Herman; Verstraete, Willy

2005-08-01

Biofiltration has been increasingly used for cleaning waste gases, mostly containing low concentrations of odorous compounds. To expand the application area of this technology, the biofiltration of higher pollutant loading rates has to be investigated. This article focuses on the biodegradation of isobutanal (IBAL) in a compost biofilter (BF) at mass loading rates between 211 and 4123 g/m3/day (30-590 ppm(v)). At mass loading rates up to 785 g/m3/day, near 100% removal efficiencies could be obtained. However, after increasing the loading rate to 1500-1900 g/m3/ day, the degradation efficiency decreased to 62-98%. In addition, a pH decrease and production of isobutanol (IBOL) and isobutyric acid (IBAC) were observed. This is the first report showing that an aldehyde can act as electron donor as well as acceptor in a BF. To study the effects of pH, compost moisture content, and electron acceptor availability on the biofiltration of IBAL, IBOL, and IBAC, additional batch and continuous experiments were performed. A pH of 5.2 reduced the IBAL degradation rate and inhibited the IBOL degradation, although adaptation of the microorganisms to low pH was observed in the BFs. IBAC was not degraded in the batch experiments. High moisture content (51%) initially had no effect on the IBOL production, although it negatively affected the IBAL elimination increasingly during a 21-day time-course experiment. In batch experiments, the reduction of IBAL to IBOL did not decrease when the amount of available electron acceptors (oxygen or nitrate) was increased. The IBAL removal efficiency at higher loading rates was limited by a combination of nutrient limitation, pH decrease, and dehydration, and the importance of each limiting factor depended on the influent concentration.

Doxorubicin-loaded poly (lactic-co-glycolic acid) nanoparticles coated with chitosan/alginate by layer by layer technology for antitumor applications.

PubMed

Chai, Fujuan; Sun, Linlin; He, Xinyi; Li, Jieli; Liu, Yuanfen; Xiong, Fei; Ge, Liang; Webster, Thomas J; Zheng, Chunli

2017-01-01

Natural polyelectrolyte multilayers of chitosan (CHI) and alginate (ALG) were alternately deposited on doxorubicin (DOX)-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) with layer by layer self-assembly to control drug release for antitumor activity. Numerous factors which influenced the multilayer growth on nano-colloidal particles were studied: polyelectrolyte concentration, NaCl concentration and temperature. Then the growth regime of the CHI/ALG multilayers was elucidated. The coated NPs were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction and a zeta potential analyzer. In vitro studies demonstrated an undesirable initial burst release of DOX-loaded PLGA NPs (DOX-PLGA NPs), which was relieved from 55.12% to 5.78% through the use of the layer by layer technique. The release of DOX increased more than 40% as the pH of media decreased from 7.4 to 5.0. More importantly, DOX-PLGA (CHI/ALG) 3 NPs had superior in vivo tumor inhibition rates at 83.17% and decreased toxicity, compared with DOX-PLGA NPs and DOX in solution. Thus, the presently formulated PLGA-polyelectrolyte NPs have strong potential applications for numerous controlled anticancer drug release applications.

An insight on acyl migration in solvent-free ethanolysis of model triglycerides using Novozym 435.

PubMed

Sánchez, Daniel Alberto; Tonetto, Gabriela Marta; Ferreira, María Luján

2016-02-20

In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20mg), reaction time (30-90min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase. Copyright © 2016 Elsevier B.V. All rights reserved.

Coseeded Schwann cells myelinate neurites from differentiated neural stem cells in neurotrophin-3-loaded PLGA carriers

PubMed Central

Xiong, Yi; Zhu, Ji-Xiang; Fang, Zheng-Yu; Zeng, Cheng-Guang; Zhang, Chao; Qi, Guo-Long; Li, Man-Hui; Zhang, Wei; Quan, Da-Ping; Wan, Jun

2012-01-01

Biomaterials and neurotrophic factors represent promising guidance for neural repair. In this study, we combined poly-(lactic acid-co-glycolic acid) (PLGA) conduits and neurotrophin-3 (NT-3) to generate NT-3-loaded PLGA carriers in vitro. Bioactive NT-3 was released stably and constantly from PLGA conduits for up to 4 weeks. Neural stem cells (NSCs) and Schwann cells (SCs) were coseeded into an NT-releasing scaffold system and cultured for 14 days. Immunoreactivity against Map2 showed that most of the grafted cells (>80%) were differentiated toward neurons. Double-immunostaining for synaptogenesis and myelination revealed the formation of synaptic structures and myelin sheaths in the coculture, which was also observed under electron microscope. Furthermore, under depolarizing conditions, these synapses were excitable and capable of releasing synaptic vesicles labeled with FM1-43 or FM4-64. Taken together, coseeding NSCs and SCs into NT-3-loaded PLGA carriers increased the differentiation of NSCs into neurons, developed synaptic connections, exhibited synaptic activities, and myelination of neurites by the accompanying SCs. These results provide an experimental basis that supports transplantation of functional neural construction in spinal cord injury. PMID:22619535

Novel micelle formulation of curcumin for enhancing antitumor activity and inhibiting colorectal cancer stem cells

PubMed Central

Wang, Ke; Zhang, Tao; Liu, Lina; Wang, Xiaolei; Wu, Ping; Chen, Zhigang; Ni, Chao; Zhang, Junshu; Hu, Fuqiang; Huang, Jian

2012-01-01

Background and methods: Curcumin has extraordinary anticancer properties but has limited use due to its insolubility in water and instability, which leads to low systemic bioavailability. We have developed a novel nanoparticulate formulation of curcumin encapsulated in stearic acid-g-chitosan oligosaccharide (CSO-SA) polymeric micelles to overcome these hurdles. Results: The synthesized CSO-SA copolymer was able to self-assemble to form nanoscale micelles in aqueous medium. The mean diameter of the curcumin-loaded CSO-SA micelles was 114.7 nm and their mean surface potential was 18.5 mV. Curcumin-loaded CSO-SA micelles showed excellent internalization ability that increased curcumin accumulation in cancer cells. Curcumin-loaded CSO-SA micelles also had potent antiproliferative effects on primary colorectal cancer cells in vitro, resulting in about 6-fold greater inhibition compared with cells treated with a solution containing an equivalent concentration of free curcumin. Intravenous administration of curcumin-loaded CSO-SA micelles marginally suppressed tumor growth but did not increase cytotoxicity to mice, as confirmed by no change in body weight. Most importantly, curcumin-loaded CSO-SA micelles were effective for inhibiting subpopulations of CD44+/CD24+ cells (putative colorectal cancer stem cell markers) both in vitro and in vivo. Conclusion: The present study identifies an effective and safe means of using curcumin-loaded CSO-SA micelles for cancer therapy. PMID:22927762

Midlife women, bone health, vegetables, herbs and fruit study. The Scarborough Fair study protocol.

PubMed

Gunn, Caroline A; Weber, Janet L; Kruger, Marlena C

2013-01-10

Bone loss is accelerated in middle aged women but increased fruit/vegetable intake positively affects bone health by provision of micronutrients essential for bone formation, buffer precursors which reduce acid load and phytochemicals affecting inflammation and oxidative stress. Animal studies demonstrated bone resorption inhibiting properties of specific vegetables, fruit and herbs a decade ago. To increase fruit/vegetable intake in post menopausal women to 9 servings/day using a food specific approach to significantly reduce dietary acid load and include specific vegetables, fruit and herbs with bone resorbing inhibiting properties to assess effect on bone turnover, metabolic and inflammatory markers. The Scarborough Fair Study is a randomised active comparator controlled multi centre trial. It aimed to increase fruit and vegetable intake in 100 post menopausal women from ≤ 5 servings/day to ≥ 9 servings/day for 3 months. The women in the dietary intervention were randomly assigned to one of the two arms of the study. Both groups consumed ≥ 9 servings/day of fruit/vegetables and selected herbs but the diet of each group emphasised different fruit/vegetables/herbs with one group (B) selecting from a range of vegetables, fruit and culinary herbs with bone resorbing inhibiting properties. 50 women formed a negative control group (Group C usual diet). Primary outcome variables were plasma bone markers assessed at baseline, 6 weeks and 12 weeks. Secondary outcome variables were plasma inflammation and metabolic markers and urinary electrolytes (calcium, magnesium, potassium and sodium) assessed at baseline and 12 weeks. Dietary intake and urine pH change also were outcome variables. The dietary change was calculated with 3 day diet diaries and a 24 hour recall. Intervention participants kept a twice weekly record of fruit, vegetable and herb intake and urine pH. This study will provide information on midlife women's bone health and how a dietary intervention increasing fruit and vegetable/herb intake affects bone, inflammatory and metabolic markers and urinary electrolyte excretion. It assesses changes in nutrient intake, estimated dietary acid load and sodium: potassium ratios. The study also explores whether specific fruit/vegetables and herbs with bone resorbing properties has an effect on bone markers. ACTRN 12611000763943.

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion

PubMed Central

Garbayo, Elisa; Gavira, Juan José; de Yebenes, Manuel Garcia; Pelacho, Beatriz; Abizanda, Gloria; Lana, Hugo; Blanco-Prieto, María José; Prosper, Felipe

2016-01-01

Cardiovascular protein therapeutics such as neuregulin (NRG1) and acidic-fibroblast growth factor (FGF1) requires new formulation strategies that allow for sustained bioavailability of the drug in the infarcted myocardium. However, there is no FDA-approved injectable protein delivery platform due to translational concerns about biomaterial administration through cardiac catheters. We therefore sought to evaluate the efficacy of percutaneous intramyocardial injection of poly(lactic-co-glycolic acid) microparticles (MPs) loaded with NRG1 and FGF1 using the NOGA MYOSTAR injection catheter in a porcine model of ischemia-reperfusion. NRG1- and FGF1-loaded MPs were prepared using a multiple emulsion solvent-evaporation technique. Infarcted pigs were treated one week after ischemia-reperfusion with MPs containing NRG1, FGF1 or non-loaded MPs delivered via clinically-translatable percutaneous transendocardial-injection. Three months post-treatment, echocardiography indicated a significant improvement in systolic and diastolic cardiac function. Moreover, improvement in bipolar voltage and decrease in transmural infarct progression was demonstrated by electromechanical NOGA-mapping. Functional benefit was associated with an increase in myocardial vascularization and remodeling. These findings in a large animal model of ischemia-reperfusion demonstrate the feasibility and efficacy of using MPs as a delivery system for growth factors and provide strong evidence to move forward with clinical studies using therapeutic proteins combined with catheter-compatible biomaterials. PMID:27184924

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion

NASA Astrophysics Data System (ADS)

Garbayo, Elisa; Gavira, Juan José; de Yebenes, Manuel Garcia; Pelacho, Beatriz; Abizanda, Gloria; Lana, Hugo; Blanco-Prieto, María José; Prosper, Felipe

2016-05-01

Cardiovascular protein therapeutics such as neuregulin (NRG1) and acidic-fibroblast growth factor (FGF1) requires new formulation strategies that allow for sustained bioavailability of the drug in the infarcted myocardium. However, there is no FDA-approved injectable protein delivery platform due to translational concerns about biomaterial administration through cardiac catheters. We therefore sought to evaluate the efficacy of percutaneous intramyocardial injection of poly(lactic-co-glycolic acid) microparticles (MPs) loaded with NRG1 and FGF1 using the NOGA MYOSTAR injection catheter in a porcine model of ischemia-reperfusion. NRG1- and FGF1-loaded MPs were prepared using a multiple emulsion solvent-evaporation technique. Infarcted pigs were treated one week after ischemia-reperfusion with MPs containing NRG1, FGF1 or non-loaded MPs delivered via clinically-translatable percutaneous transendocardial-injection. Three months post-treatment, echocardiography indicated a significant improvement in systolic and diastolic cardiac function. Moreover, improvement in bipolar voltage and decrease in transmural infarct progression was demonstrated by electromechanical NOGA-mapping. Functional benefit was associated with an increase in myocardial vascularization and remodeling. These findings in a large animal model of ischemia-reperfusion demonstrate the feasibility and efficacy of using MPs as a delivery system for growth factors and provide strong evidence to move forward with clinical studies using therapeutic proteins combined with catheter-compatible biomaterials.

Development of Functional or Medical Foods for Oral Administration of Insulin for Diabetes Treatment: Gastroprotective Edible Microgels.

PubMed

Sun, Quancai; Zhang, Zipei; Zhang, Ruojie; Gao, Ruichang; McClements, David Julian

2018-05-16

Insulin and an antacid [Mg(OH) 2 ] were co-encapsulated inside calcium alginate microgels (diameter = 280 μm) using a vibrating nozzle injector. Confocal microscopy indicated that insulin was successfully encapsulated inside the microgels and remained inside them after they were exposed to simulated gastric conditions. Localized fluorescence intensity measurements indicated that the internal pH of the antacid-loaded microgels was around pH 7.4 after incubation in acidic gastric fluids but below the limit of detection (pH < 4) in the antacid-free microgels. After incubation in small intestine conditions, around 30% of the insulin was released from the antacid-loaded microgels over a 2 h period. Encapsulation of insulin within the antacid-loaded microgels increased its biological activity after exposure to simulated gastric conditions. In particular, the encapsulated insulin significantly increased Akt phosphorylation at both Thr308 and Ser473 in L6 myotubes when compared to free insulin.

Ibuprofen-loaded poly(lactic-co-glycolic acid) films for controlled drug release.

PubMed

Pang, Jianmei; Luan, Yuxia; Li, Feifei; Cai, Xiaoqing; Du, Jimin; Li, Zhonghao

2011-01-01

Ibuprofen- (IBU) loaded biocompatible poly(lactic-co-glycolic acid) (PLGA) films were prepared by spreading polymer/ibuprofen solution on the nonsolvent surface. By controlling the weight ratio of drug and polymer, different drug loading polymer films can be obtained. The synthesized ibuprofen-loaded PLGA films were characterized with scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry. The drug release behavior of the as-prepared IBU-loaded PLGA films was studied to reveal their potential application in drug delivery systems. The results show the feasibility of the as-obtained films for controlling drug release. Furthermore, the drug release rate of the film could be controlled by the drug loading content and the release medium. The development of a biodegradable ibuprofen system, based on films, should be of great interest in drug delivery systems.

Manipulating electronic and mechanical properties at metal-ceramic interfaces with a nanomolecular layer

NASA Astrophysics Data System (ADS)

Kwan, Matthew P.

This work demonstrates that inserting nanomolecular layers (NMLs) can profoundly change and/or lead to novel electronic and mechanical properties of metal-ceramic interfaces. The first set of results demonstrate that organophosphonate NMLs up to 1.8 nm thick can alter metal work functions by +/- 0.6 eV. This work function change is a strong function of the NML terminal groups (methyl, mercaptan, carboxylic acid, or phosphonic acid), morphology (up right, lying down, or mixed orientation), and the nature of the bonding (covalent, polar, or Van der Waals) between NML and the adjacent layers. Additionally, while NML-ceramic bond type and strength can influence and counteract the effect of NML morphology, the metal-NML bond appears to be independent of the morphology of the NML underlayer. The second set of results demonstrate that inserting an organosilane NML at a metal-ceramic interface can lead to multifold fracture toughening under both static (stress corrosion) and cyclic loads (fatigue) tested in four-point bend. Nanolayer-induced interface strengthening during static loading activates metal plasticity above the metal yield strength, leading to two-fold fracture toughening. Metal plasticity-induced toughening increases as temperature is increased up to 85 °C due to decreasing yield stress. In the fatigue fracture tests I report for the first time a loading-frequency-dependent tripling in fracture toughening in the 75-300 Hz range upon inserting a mercapto-silane NML at the weakest interface of a ceramic-polymer-metal-ceramic stack. This unusual behavior arises from the NML strengthened interface enabling load transfer to- and plasticity in the polymer layer, while the fatigue toughening magnitude and frequency range are determined by polymer rheology.

Intracellular pH regulation in hepatocytes isolated from three teleost species.

PubMed

Furimsky, M; Moon, T W; Perry, S F

1999-09-01

The mechanisms of intracellular pH (pH(i)) regulation were studied in hepatocytes isolated from three species of teleost: rainbow trout (Oncorhynchus mykiss), black bullhead (Ameiurus melas) and American eel (Anguilla rostrata). Intracellular pH was monitored over time using the pH-sensitive fluorescent dye BCECF in response to acid loading under control conditions and in different experimental media containing either low Na(+) or Cl(-) concentrations, the Na(+)-H(+) exchanger blocker amiloride or the blocker of the V-type H(+)-ATPase, bafilomycin A(1). In trout and bullhead hepatocytes, recovery to an intracellular acid load occurred principally by way of a Na(+)-dependent amiloride-sensitive Na(+)-H(+) exchanger. In eel hepatocytes, the Na(+)-H(+) exchanger did not contribute to recovery to an acid load though evidence suggests that it is present on the cell membrane and participates in the maintenance of steady-state pH(i). The V-type H(+)-ATPase did not participate in recovery to an acid load in any species. A Cl(-)-HCO(3)(-) exchanger may play a role in recovery to an acid load in eel hepatocytes by switching off and retaining base that would normally be tonically extruded. Thus, it is clear that hepatocytes isolated from the three species are capable of regulating pH(i), principally by way of a Na(+)-H(+) exchanger and a Cl(-)-HCO(3)(-) exchanger, but do not exploit identical mechanisms for pH(i) recovery. J. Exp. Zool. 284:361-367, 1999. Copyright 1999 Wiley-Liss, Inc.

Development of γ-Oryzanol Rich Extract from Leum Pua Glutinous Rice Bran Loaded Nanostructured Lipid Carriers for Topical Delivery.

PubMed

Pornputtapitak, Warangkana; Pantakitcharoenkul, Jaturavit; Panpakdee, Ratchada; Teeranachaideekul, Veerawat; Sinchaipanid, Nuttanan

2018-02-01

Leum Pua is native Thai glutinous rice that contains antioxidants higher than white rice and other colored rice. One of the major antioxidants in rice brans is γ-oryzanol (GO). In this study, Leum Pua glutinous rice bran was extracted by different solvents. Oleic acid (~40 g/100 g extract), linoleic acid (~30 g/100 g extract), and palmitic acid (~20 g/100 g extract) were found to be major lipid components in the extracts. Methanol extract showed less variety of lipid components compared to the others. However, hexane extract showed the highest percent of γ-oryzanol compared to other solvents. Therefore, the hexane extract was selected to prepare nanostructured lipid carriers (NLC). The prepared NLC had small particles in the size range of 142.9 ± 0.4 nm for extract-loaded NLC and 137.1 ± 0.5 nm for GO-loaded NLC with narrow size distribution (PI < 0.1) in both formulations. The release profile of extract-loaded NLC formulation was slightly higher than GO-loaded NLC formulation. However, they did not follow the Higuchi model because of small amounts of γ-oryzanol loaded in NLC particles.

Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

NASA Astrophysics Data System (ADS)

Sharma, Disha; Kulshrestha, Umesh

Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

Compressibility of binary powder formulations: investigation and evaluation with compaction equations.

PubMed

Gentis, Nicolaos D; Betz, Gabriele

2012-02-01

The purpose of this work was to investigate and evaluate the powder compressibility of binary mixtures containing a well-compressible compound (microcrystalline cellulose) and a brittle active drug (paracetamol and mefenamic acid) and its progression after a drug load increase. Drug concentration range was 0%-100% (m/m) with 10% intervals. The powder formulations were compacted to several relative densities with the Zwick material tester. The compaction force and tensile strength were fitted to several mathematical models that give representative factors for the powder compressibility. The factors k and C (Heckel and modified Heckel equation) showed mostly a nonlinear correlation with increasing drug load. The biggest drop in both factors occurred at far regions and drug load ranges. This outcome is crucial because in binary mixtures the drug load regions with higher changeover of plotted factors could be a hint for an existing percolation threshold. The susceptibility value (Leuenberger equation) showed varying values for each formulation without the expected trend of decrease for higher drug loads. The outcomes of this study showed the main challenges for good formulation design. Thus, we conclude that such mathematical plots are mandatory for a scientific evaluation and prediction of the powder compaction process. Copyright © 2011 Wiley Periodicals, Inc.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

PubMed

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

Preparation, characterization and in vivo evaluation of a combination delivery system based on hyaluronic acid/jeffamine hydrogel loaded with PHBV/PLGA blend nanoparticles for prolonged delivery of Teriparatide.

PubMed

Bahari Javan, Nika; Montazeri, Hamed; Rezaie Shirmard, Leila; Jafary Omid, Nersi; Barbari, Ghullam Reza; Amini, Mohsen; Ghahremani, Mohammad Hossein; Rafiee-Tehrani, Morteza; Abedin Dorkoosh, Farid

2017-04-01

In the current study, biodegradable PHBV/PLGA blend nanoparticles (NPs) containing Teriparatide were loaded in hyaluronic acid/jeffamine (HA-JEF ED-600) hydrogel to prepare a combination delivery system (CDS) for prolonged delivery of Teriparatide. The principal purpose of the present study was to formulate an effective and prolonged Teriparatide delivery system in order to reduce the frequency of injection and thus enhance patient's compliance. Morphological properties, swelling behaviour, crosslinking efficiency and rheological characterization of HA-JEF ED-600 hydrogel were evaluated. The CDS was acquired by adding PHBV/PLGA NPs to HA-JEF ED-600 hydrogel simultaneously with crosslinking reaction. The percentage of NPs incorporation within the hydrogel as well as the loading capacity and morphology of Teriparatide loaded CDS were examined. Intrinsic fluorescence and circular dichroism spectroscopy proved that Teriparatide remains stable after processing. The release profile represented 63% Teriparatide release from CDS within 50days with lower burst release compared to NPs and hydrogel. MTT assay was conducted by using NIH3T3 cell line and no sign of reduction in cell viability was observed. Based on Miller and Tainter method, LD 50 of Teriparatide loaded CDS was 131.8mg/kg. In vivo studies demonstrated that Teriparatide loaded CDS could effectively increase serum calcium level after subcutaneous injection in mice. Favourable results in the current study introduced CDS as a promising candidate for controlled delivery of Teriparatide and pave the way for future investigations in the field of designing prolonged delivery systems for other peptides and proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

Folic acid-conjugated soybean protein-based nanoparticles mediate efficient antitumor ability in vitro.

PubMed

Yao, Weijing; Zha, Qian; Cheng, Xu; Wang, Xin; Wang, Jun; Tang, Rupei

2016-11-23

In this study, soy protein isolate was hydrolyzed by compound enzymes to give aqueous soy protein with low molecular weights. Folic acid modified and free soy protein nanoparticles were successfully prepared by a desolvation method as target-specific drug delivery, respectively. Ultraviolet spectrophotometry demonstrated that folic acid was successfully grafted onto soy protein. The shape and size of folic acid modified soy protein nanoparticles were detected by transmission electron microscopy, scanning electron microscope, and dynamic light scattering. In addition, a series of characteristics including kinetic stability, pH stability, and time stability were also performed. Doxorubicin was successfully loaded into folic acid modified soy protein nanoparticles, and the encapsulation and loading efficiencies were 96.7% and 23%, respectively. Doxorubicin-loaded folic acid modified soy protein nanoparticles exhibited faster drug release rate than soy protein nanoparticles in PBS solution (pH = 5). The tumor penetration and antitumor experiments were done using three-dimensional multicellular tumor spheroids as the in vitro model. The results proved that folic acid modified soy protein nanoparticles display higher penetration and accumulation than soy protein nanoparticles, therefore possessing efficient growth inhibitory ability against multicellular tumor spheroids. © The Author(s) 2016.

Simultaneous saccharification and cofermentation of peracetic acid-pretreated biomass.

PubMed

Teixeira, L C; Linden, J C; Schroeder, H A

2000-01-01

Previous work in our laboratories has demonstrated the effectiveness of peracetic acid for improving enzymatic digestibility of lignocellulosic materials. The use of dilute alkali solutions as a pre-pretreatment prior to peracetic acid lignin oxidation increased carbohydrate hydrolysis yields in a synergistic as opposed to additive manner. Deacetylation of xylan is easily achieved using dilute alkali solutions under mild conditions. In this article, we evaluate the effectiveness of peracetic acid combined with an alkaline pre-pretreatment through simultaneous saccharification and cofermentation (SSCF) of pretreated hybrid poplar wood and sugar cane bagasse. Respective ethanol yields of 92.8 and 91.9% of theoretical are achieved using 6% NaOH/15% peracetic acid-pretreated substrates and recombinant Zymomonas mobilis CP4/pZB5. Reduction of acetyl groups of the lignocellulosic materials is demonstrated following alkaline pre-pretreatments. Such processing may be helpful in reducing peracetic acid requirements. The influence of deacetylation is more significant in combined pretreatments using lower peracetic acid loadings.

Seasonal inorganic nitrogen release in alpine lakes on the Colorado western slope

USGS Publications Warehouse

Inyan, B.I.; Williams, M.W.; Tonnessen, K.; Turk, J.T.; Campbell, D.H.

1998-01-01

In the Rocky Mountains, the association of increases in acidic deposition with increased atmospheric loading of sulfate and direct changes in surface water chemistry has been well established. The importance, though, of increased nitrogen (N) deposition in the episodic acidification of alpine lakes and N saturation in alpine ecosystems is only beginning to be documented. In alpine areas of the Colorado Front Range, modest loadings of N in deposition have been associated with leakage of N to surface waters. On the Colorado western slope, however, no leakage of N to surface waters has been reported. A 1995 study that included early season under-ice water samples that were not available in earlier studies showed that there is, in fact, N leakage to surface waters in some western slope basins. Under-ice nitrate (NO3-) concentrations were as high as 10.5 ??q L-1, and only decreased to detection limits in September. Landscape type appears to be important in leakage of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock. NO3- leakage compounds the existing sensitivity to episodic acidification from low acid neutralizing capacity (ANC), which is less than 40 ??eq L-1 in those basins.

Improvement in Electrode Performance of Novel SWCNT Loaded Three-Dimensional Porous RVC Composite Electrodes by Electrochemical Deposition Method

PubMed Central

Almoigli, Mohammed; Meriey, Al Yahya; Alharbi, Khalid N.

2018-01-01

The three-dimensional (3D) composite electrodes were prepared by depositing different amounts of acid-functionalized single-walled carbon nanotubes (a-SWCNTs) on porous reticulated vitreous carbon (RVC) through the electrochemical deposition method. The SWCNT was functionalized by the reflux method in nitric acid and was proven by Raman and visible spectra. The optimum time for sonication to disperse the functionalized SWCNT (a-SWCNT) in dimethyl formamide (DMF) well was determined by UV spectra. The average pore size of RVC electrodes was calculated from scanning electron microscopy (SEM) images. Moreover, the surface morphology of composite electrodes was also examined by SEM study. All 3D electrodes were evaluated for their electrochemical properties by cyclic voltammetry. The result showed that the value of specific capacitance of the electrode increases with the increase in the amount of a-SWCNT in geometric volume. However, the value of specific capacitance per gram decreases with the increase in scan rate as well as the amount of a-SWCNT. The stability of the electrodes was also tested. This revealed that all the electrodes were stable; however, lower a-SWCNT-loaded electrodes had excellent cyclic stability. These results suggest that the a-SWCNT-coated RVC electrodes have promise as an effective technology for desalination. PMID:29301258

Improvement in Electrode Performance of Novel SWCNT Loaded Three-Dimensional Porous RVC Composite Electrodes by Electrochemical Deposition Method.

PubMed

Aldalbahi, Ali; Rahaman, Mostafizur; Almoigli, Mohammed; Meriey, Al Yahya; Alharbi, Khalid N

2018-01-01

The three-dimensional (3D) composite electrodes were prepared by depositing different amounts of acid-functionalized single-walled carbon nanotubes (a-SWCNTs) on porous reticulated vitreous carbon (RVC) through the electrochemical deposition method. The SWCNT was functionalized by the reflux method in nitric acid and was proven by Raman and visible spectra. The optimum time for sonication to disperse the functionalized SWCNT (a-SWCNT) in dimethyl formamide (DMF) well was determined by UV spectra. The average pore size of RVC electrodes was calculated from scanning electron microscopy (SEM) images. Moreover, the surface morphology of composite electrodes was also examined by SEM study. All 3D electrodes were evaluated for their electrochemical properties by cyclic voltammetry. The result showed that the value of specific capacitance of the electrode increases with the increase in the amount of a-SWCNT in geometric volume. However, the value of specific capacitance per gram decreases with the increase in scan rate as well as the amount of a-SWCNT. The stability of the electrodes was also tested. This revealed that all the electrodes were stable; however, lower a-SWCNT-loaded electrodes had excellent cyclic stability. These results suggest that the a-SWCNT-coated RVC electrodes have promise as an effective technology for desalination.

Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids

USGS Publications Warehouse

Scott, Durelle T.; Runkel, Robert L.; McKnight, Diane M.; Voelker, Bettina M.; Kimball, Briant A.; Carraway, Elizabeth R.

2003-01-01

An in-stream injection of two dissolved organic acids (phthalic and aspartic acids) was performed in an acidic mountain stream to assess the effects of organic acids on Fe photoreduction and H2O2 cycling. Results indicate that the fate of Fe is dependent on a net balance of oxidative and reductive processes, which can vary over a distance of several meters due to changes in incident light and other factors. Solution phase photoreduction rates were high in sunlit reaches and were enhanced by the organic acid addition but were also limited by the amount of ferric iron present in the water column. Fe oxide photoreduction from the streambed and colloids within the water column resulted in an increase in the diurnal load of total filterable Fe within the experimental reach, which also responded to increases in light and organic acids. Our results also suggest that Fe(II) oxidation increased in response to the organic acids, with the result of offsetting the increase in Fe(II) from photoreductive processes. Fe(II) was rapidly oxidized to Fe(III) after sunset and during the day within a well-shaded reach, presumably through microbial oxidation. H2O 2, a product of dissolved organic matter photolysis, increased downstream to maximum concentrations of 0.25 ??M midday. Kinetic calculations show that the buildup of H2O2 is controlled by reaction with Fe(III), but this has only a small effect on Fe(II) because of the small formation rates of H2O2 compared to those of Fe(II). The results demonstrate the importance of incorporating the effects of light and dissolved organic carbon into Fe reactive transport models to further our understanding of the fate of Fe in streams and lakes.

Nanostructured lipid carriers for the topical delivery of tretinoin.

PubMed

Ghate, Vivek M; Lewis, Shaila A; Prabhu, Prabhakara; Dubey, Akhilesh; Patel, Nilkumar

2016-11-01

Cosmetic skin care products currently in the market demonstrate an increasing trend toward antiaging products. Selection of the right formulation approach is the key to successful consumer acceptance. Nanostructured lipid carriers (NLCs) for dermal application can render added benefits to the formulation. Tretinoin a derivative of vitamin A, is a retinoid with anti-aging and anti-acne potential. The present study was aimed at formulating NLCs of tretinoin for reducing the skin irritation potential, increasing the drug loading capacity and prolonging the duration of action. The NLCs were optimized using the response surface methodology based on the particle size. Preliminary study, suggested the use of stearic acid, oleic acid, Tween 80 and Span 60 as solid lipid, liquid lipid and surfactants respectively formed a stable dispersion. NLCs of tretinoin were prepared by hot melt microemulsion and hot melt probe sonication methods. The properties of the optimized NLCs such as morphology, size, Zeta potential, stability and in vitro drug release were investigated. Tretinoin loaded NLCs in carbopol gel showed a sustained release pattern with isopropyl alcohol as the receptor fluid compared to the marketed gel using Franz diffusion cells. Eight prepared gel formulations tested were found to follow the Higuchi model of drug release. Stability studies indicated that the formulations stored at refrigeration and room temperature showed no noticeable differences in the drug content and release profiles in vitro, after a period of 4 weeks. In vivo skin irritation test on male Wister rats indicated no irritation or erythema after application of the NLCs loaded gel repeated for a period of 7 days compared to the application of marketed tretinoin gel which showed irritation and slight erythema within 3 days. The results showed that the irritation potential of tretinoin was reduced, the drug loading was increased and the drug release was prolonged by the incorporation into the NLCs. Copyright © 2016 Elsevier B.V. All rights reserved.

Pollution Critical Load Exceedance and an Extended Growing Season as Modulators of Red Spruce Radial Growth

NASA Astrophysics Data System (ADS)

Kosiba, A. M.; Schaberg, P. G.; Engel, B. J.; Rayback, S. A.; Hawley, G. J.; Pontius, J.; Miller, E. K.

2016-12-01

Acidic sulfur (S) and nitrogen (N) deposition depletes cations such as calcium (Ca) from forest soils and has been linked to increases in foliar winter injury that led to the decline of red spruce (Picea rubens Sarg.) in the northeastern United States. We used results from a 30 m resolution steady-state S and N critical load exceedance model for New England to better understand the spatial connections between Ca depletion and red spruce productivity. To calculate exceedance, atmospheric deposition was estimated for a 5-year period (1984-1988) because tree health and productivity declines were expected to be most responsive to high acid loading. We examined how radial growth (basal area increment) of 441 dominant and co-dominant red spruce trees from 37 sites across Vermont and New Hampshire was related to modeled estimates of S and N critical load exceedance. We assessed growth using statistical models with exceedance as a source of variation, but which also included "year" and "elevation class" (to help account for climatic variability) and interactions among factors. Exceedance was significantly and negatively associated with mean growth for the study period (1951-2010) overall, and particularly for the 1980s and 2000s - periods of numerous and/or severe foliar winter injury events. However, climate-related sources of variation (year and elevation) accounted for most of the differences in growth over the chronology. Interestingly, recent growth for red spruce is now the highest recorded over our dendrochronological record for the species - suggesting that the factors shaping growth may be changing. Because red spruce is a temperate conifer that has the capacity to photosynthesize year-round, it is possible that warmer temperatures may be extending the functional growing season of the species thereby fostering increased growth. Data from elevational transects on Mount Mansfield (Vermont's tallest mountain) indicate that warmer spring, summer, fall and even winter temperatures are positively correlated with increased radial growth for red spruce.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heitkamp, M.A.; Adams, W.J.; Camel, V.

Immobilized bacteria technology (IBT) utilizes inert biocarriers to support high concentrations of chemical-degrading bacteria in reactors designed to provide optimal conditions for microbial activity. This study evaluated IBT performance inpacked bed reactors (PBRs) using a porous inorganic biocarrier (diatomaceous earth), nonporous biocarriers (glass beads), and organic biocarriers having carbon adsorption properties (granular activated carbon) with different porosity. Each reactor was challenged with high chemical loading, acid, dryness, and heat shock conditions. Benchtop PBSs inoculated with a p-nitrophenol (PNP)-degrading Pseudomonas sp. and fed a synthetic waste containing 100 to 1,300 mg/L of PNP showed removal of PNP from effluents within 24more » h of start-up. Chemical loading studies showed maximum PNP removal rates of 6.45 to 7.35 kg/m[sup 3]/d for bacteria in PBRs containing diatomaceous earth beads, glass beads, and activated coconut carbon. A lower PNP removal rate of 1.47 kg/m[sup 3]/d was determined for the activated anthracite carbon, and this PBR responded more slowly to increases in chemical loading. The PBR containing bacteria immobilized on activated coconut carbon showed exceptional tolerance to acid shocking, drying, and heat shocking by maintaining PNP removal rates > 85% throughout the entire study. The other biocarriers showed nearly complete loss of PNP degradation during the perturbations, but all recovered high rates of PNP degradation (> 98% removal) within 48 h after an acid shock at pH2, within 8 d after an acid shock at pH 1.0, within 24 h after drying for 72 h, and within 48 h of heat shocking. The resiliency and high chemical removal efficiency demonstrated by immobilized bacteria in this study support the concept of using IBT for the biotreatment of industrial wastes..« less

Maternal loading with very low-density lipoproteins stimulates fetal surfactant synthesis.

PubMed

Ryan, Alan J; Medh, Jheem D; McCoy, Diann M; Salome, Ronald G; Mallampalli, Rama K

2002-08-01

We examined whether administration of very low-density lipoproteins (VLDL) to pregnant rats increases surfactant phosphatidylcholine (PtdCho) content in fetal pre-type II alveolar epithelial cells. VLDL-triglycerides are hydrolyzed to fatty acids by lipoprotein lipase (LPL), an enzyme activated by heparin. Fatty acids released by LPL can incorporate into the PtdCho molecule or activate the key biosynthetic enzyme cytidylyltransferase (CCT). Dams were given BSA, heparin, VLDL, or VLDL with heparin intravenously. Radiolabeled VLDL given to the pregnant rat crossed the placenta and was distributed systemically in the fetus and incorporated into disaturated PtdCho (DSPtdCho) in pre-type II cells. Maternal administration of VLDL with heparin increased DSPtdCho content in cells by 45% compared with control (P < 0.05). VLDL produced a dose-dependent, saturable, and selective increase in CCT activity. VLDL did not significantly alter immunoreactive CCT content but increased palmitic, stearic, and oleic acids in pre-type II cells. Furthermore, hypertriglyceridemic apolipoprotein E knockout mice contained significantly greater levels of DSPtdCho content in alveolar lavage and CCT activity compared with either LDL receptor knockout mice or wild-type controls that have normal serum triglycerides. Thus the nutritional or genetic modulation of serum VLDL-triglycerides provides specific fatty acids that stimulate PtdCho synthesis and CCT activity thereby increasing surfactant content.

Effects of cyclic fatigue stress-biocorrosion on noncarious cervical lesions.

PubMed

Grippo, John O; Chaiyabutr, Yada; Kois, John C

2013-08-01

Although there is a high prevalence of noncarious cervical lesions (NCCLs), the etiology of these lesions remains contentious. To evaluate the combined effects of cyclic fatigue stress and biocorrosion activity on NCCLs. Extracted premolar teeth were allocated into four groups (N = 10). Two groups were cyclically fatigue loaded (100 N; 72 cycles per minute; 9,200 cycles) and placed in either hydrochloric acid gel (pH = 0.1) or orange juice (pH = 4). The other two groups were stored in identical chemical solutions without fatigue load. The buccal-lingual width of each tooth was measured before and after testing. The depth of biocorrosion, normalized by the percentage change in buccolingual width, normalized by time (hour) was calculated. The data were analyzed using a two-way analysis of variance and Tukey's HSD multiple comparison test (α = 0.05). Mean (SD) of the depth of biocorrosion values were as follows: teeth receiving fatigue loading with hydrochloric acid gel exposure (1.003%/hour [0.063]) revealed a significantly higher depth of biocorrosion than the fatigue-loaded group with orange juice exposure (0.511%/hour [0.281]) (p < 0.01). For the groups without fatigue loading, those with hydrochloric acid gel (0.022%/hour [0.006]) had a significantly higher depth of biocorrosion than the group with orange juice (0.009%/hour [0.004]) (p < 0.01). The cyclically fatigue-loaded teeth with hydrochloric acid gel had a significantly greater depth of biocorrosion than either group without fatigue loading (p < 0.001). Cyclic fatigue stress-acidic biocorrosion had a significant effect on the depth of the NCCLs. In order to manage the destructive NCCLs lesions properly, it is essential to understand the etiology of these lesions. The present study indicated that the combined mechanisms of cyclic fatigue stress and biocorrosion could contribute to the formation of NCCLs. © 2013 Wiley Periodicals, Inc.

Cosensitized Porphyrin System for High-Performance Solar Cells with TOF-SIMS Analysis.

PubMed

Wu, Wenjun; Xiang, Huaide; Fan, Wei; Wang, Jinglin; Wang, Haifeng; Hua, Xin; Wang, Zhaohui; Long, Yitao; Tian, He; Zhu, Wei-Hong

2017-05-17

To date, development of organic sensitizers has been predominately focused on light harvesting, highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels, and the electron transferring process. In contrast, their adsorption mode as well as the dynamic loading behavior onto nanoporous TiO 2 is rarely considered. Herein, we have employed the time-of-flight secondary ion mass spectrometry (TOF-SIMS) to gain insight into the competitive dye adsorption mode and kinetics in the cosensitized porphyrin system. Using novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well-compared with two different anchoring groups, such as benzoic acid and cyanoacrylic acid. With the bombardment mode in TOF-SIMS spectra, we have speculated that the cyano group grafts onto nanoporous TiO 2 as tridentate binding for the common anchoring unit of cyanoacrylic acid and confirmed it through extensive first-principles density functional theory calculation by anchoring either the carboxyl or cyano group, which shows that the cyano group can efficiently participate in the adsorption of the WS-5 molecule onto the TiO 2 nanocrystal. The grafting reinforcement interaction between the cyano group and TiO 2 in WS-5 can well-explain the rapid adsorption characteristics. A strong coordinate bond between the lone pair of electrons on the nitrogen or oxygen atom and the Lewis acid sites of TiO 2 can increase electron injection efficiencies with respect to those from the bond between the benzoic acid group and the Brønsted acid sites of the TiO 2 surface. Upon optimization of the coadsorption process with dye WS-5, the photoelectric conversion efficiency based on porphyrin dye FW-1 is increased from 6.14 to 9.72%. The study on the adsorption dynamics of organic sensitizers with TOF-SIMS analysis might provide a new venue for improvement of cosensitized solar cells.

Stewart analysis of apparently normal acid-base state in the critically ill.

PubMed

Moviat, Miriam; van den Boogaard, Mark; Intven, Femke; van der Voort, Peter; van der Hoeven, Hans; Pickkers, Peter

2013-12-01

This study aimed to describe Stewart parameters in critically ill patients with an apparently normal acid-base state and to determine the incidence of mixed metabolic acid-base disorders in these patients. We conducted a prospective, observational multicenter study of 312 consecutive Dutch intensive care unit patients with normal pH (7.35 ≤ pH ≤ 7.45) on days 3 to 5. Apparent (SIDa) and effective strong ion difference (SIDe) and strong ion gap (SIG) were calculated from 3 consecutive arterial blood samples. Multivariate linear regression analysis was performed to analyze factors potentially associated with levels of SIDa and SIG. A total of 137 patients (44%) were identified with an apparently normal acid-base state (normal pH and -2 < base excess < 2 and 35 < PaCO2 < 45 mm Hg). In this group, SIDa values were 36.6 ± 3.6 mEq/L, resulting from hyperchloremia (109 ± 4.6 mEq/L, sodium-chloride difference 30.0 ± 3.6 mEq/L); SIDe values were 33.5 ± 2.3 mEq/L, resulting from hypoalbuminemia (24.0 ± 6.2 g/L); and SIG values were 3.1 ± 3.1 mEq/L. During admission, base excess increased secondary to a decrease in SIG levels and, subsequently, an increase in SIDa levels. Levels of SIDa were associated with positive cation load, chloride load, and admission SIDa (multivariate r(2) = 0.40, P < .001). Levels of SIG were associated with kidney function, sepsis, and SIG levels at intensive care unit admission (multivariate r(2) = 0.28, P < .001). Intensive care unit patients with an apparently normal acid-base state have an underlying mixed metabolic acid-base disorder characterized by acidifying effects of a low SIDa (caused by hyperchloremia) and high SIG combined with the alkalinizing effect of hypoalbuminemia. © 2013.

Standardization of formulations for the acute amino acid depletion and loading test

PubMed Central

Badawy, Abdulla A-B; Dougherty, Donald M

2017-01-01

The acute tryptophan (Trp) depletion (ATD) and loading (ATL) and the acute tyrosine (Tyr) plus phenylalanine (Phe) depletion (ATPD) tests are powerful tools for studying the roles of cerebral monoamines in behaviour and symptoms related to various disorders. The tests use either amino acid mixtures or proteins. Current amino acid mixtures lack specificity in humans, but not in rodents, because of the faster disposal of branched-chain amino acids (BCAA) by the latter. The high content of BCAA (30-60%) is responsible for the poor specificity in humans and we recommend, in a 50g dose, the control formulation of Young et al. (1985) with a lowered BCAA content (18%) and minor modifications as a common control for the above tests. With protein-based formulations, α-lactalbumin is specific for ATL, whereas gelatine is only partially effective for ATD. We recommend the use of the whey protein fraction glycomacropeptide (GMP) as an alternative protein. Its BCAA content is ideal for specificity and the absence of Trp, Tyr and Phe render it suitable as a template for 7 formulations (separate and combined depletion or loading and a truly balanced control). We invite the research community to participate in standardization of the depletion and loading methodologies by using our recommended amino acid formulation and developing those based on GMP. PMID:25586395

Spatial distribution and partition of perfluoroalkyl acids (PFAAs) in rivers of the Pearl River Delta, southern China.

PubMed

Liu, Baolin; Zhang, Hong; Xie, Liuwei; Li, Juying; Wang, Xinxuan; Zhao, Liang; Wang, Yanping; Yang, Bo

2015-08-15

This study investigated the occurrence of perfluoroalkyl acids (PFAAs) in surface water from 67 sampling sites along rivers of the Pearl River Delta in southern China. Sixteen PFAAs, including perfluoroalkyl carboxylic acids (PFCAs, C5-14, C16 and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8 and C10) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFAA concentrations (∑ PFAAs) in the surface water ranged from 1.53 to 33.5 ng·L(-1) with an average of 7.58 ng·L(-1). Perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) were the three most abundant PFAAs and on average accounted for 28%, 16% and 10% of ∑ PFAAs, respectively. Higher concentrations of ∑ PFAAs were found in the samples collected from Jiangmen section of Xijiang River, Dongguan section of Dongjiang River and the Pearl River flowing the cities which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of extracted sources. Factor 1 (72.48% of the total variance) had high loading for perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), PFBS and PFOS. For factor 2 (10.93% of the total variance), perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUdA) got high loading. The sorption of PFCAs on suspended particulate matter (SPM) increased by approximately 0.1 log units for each additional CF2 moiety and that on sediment was approximately 0.8 log units lower than the SPM logKd values. In addition, the differences in the partition coefficients were influenced by the structure discrepancy of absorbents and influx of fresh river water. These data are essential for modeling the transport and environmental fate of PFAAs. Copyright © 2015 Elsevier B.V. All rights reserved.

Packed- and fluidized-bed biofilm reactor performance for anaerobic wastewater treatment.

PubMed

Denac, M; Dunn, I J

1988-07-05

Anaerobic degradation performance of a laboratory-scale packed-bed reactor (PBR) was compared with two fluidized-bed biofilm reactors (FBRs) on molasses and whey feeds. The reactors were operated under constant pH (7) and temperature (35 degrees C) conditions and were well mixed with high recirculation rates. The measured variables were chemical oxygen demand (COD), individual organic acids, gas composition, and gas rates. As carrier, sand of 0.3-0.5 mm diameter was used in the FBR, and porous clay spheres of 6 mm diameter were used in the PBR. Startup of the PBR was achieved with 1-5 day residence times. Start-up of the FBR was only successful if liquid residence times were held low at 2-3 h. COD degradations of 86% with molasses (90% was biodegradable) were reached in both the FBR and PBR at 6 h residence time and loadings of 10 g COD/L day. At higher loadings the FBR gave the best performance; even at 40-45 g COD/L day, with 6 h residence times, 70% COD was degraded. The PBR could not be operated above 20 g COD/L day without clogging. A comparison of the reaction rates show that the PBR and FBR per formed similarly at low concentrations in the reactors up to 1 g COD/L, while above 3 g COD/L the rates were 17.4 g COD/L day for the PBR and 38.4 g COD/L day for the FBR. This difference is probably due to diffusion limitations and a less active biomass content of the PBR compared with the fluidized bed.The results of dynamic step change experiments, in which residence times and feed concentrations were changed hanged at constant loading, demonstrated the rapid response of the reactors. Thus, the response times for an increase in gas rate or an increase in organic acids due to an increase in feed concentration were less than 1 day and could be explained by substrate limitation. Other slower responses were observed in which the reactor culture adapted over periods of 5-10 days; these were apparently growth related. An increase in loading of over 100% always resulted in large increases inorganic acids, especially acetic and propionic, as well as large increases in the CO(2) gas content. In general, the CO(2) content of the gas was very low, due to the large amount of dissolved CO(2) that exited with the liquid phase at low residence times. The performance of the FBR with whey was comparable to its performance with molasses, and switching of molasses to whey feed resulted in immediate good performance without adaptation.

Glycyrrhetinic acid-decorated and reduction-sensitive micelles to enhance the bioavailability and anti-hepatocellular carcinoma efficacy of tanshinone IIA.

PubMed

Chen, Fengqian; Zhang, Jinming; He, Yao; Fang, Xiefan; Wang, Yitao; Chen, Meiwan

2016-01-01

It remains a challenge to increase drug tumor-specific accumulation as well as to achieve intracellular-controlled drug release for hepatocellular carcinoma (HCC) chemotherapy. Herein, we developed a dual-functional biodegradable micellar system constituted by glycyrrhetinic acid coupling poly(ethylene glycol)-disulfide linkage-poly(lactic-co-glycolic acid) (GA-PEG-SS-PLGA) to achieve both hepatoma-targeting and redox-responsive intracellular drug release. Tanshinone IIA (TAN IIA), an effective anti-HCC drug, was encapsulated. Notably, it exhibited rapid aggregation and faster drug release in 10 mM dithiothreitol compared with the redox-insensitive control. Furthermore, GA-decorated micelles revealed HCC-specific cellular uptake in human liver cancer HepG2 cells with an energy-dependent manner, in which micropinocytosis and caveolae-mediated endocytosis were demonstrated as the major cellular pathways. The enhanced cytotoxicity and pro-apoptotic effects against HepG2 cells in vitro were observed, mediated by up-regulation of the intracellular ROS level, the increased cell cycle arrest at S phase, enhanced necrocytosis and up-regulation of caspase 3/7, P38 protein expression. In addition, TAN IIA-loaded micelles had a significantly prolonged circulation time, improved bioavailability, and resulted in an increased accumulation of TAN IIA in the liver. With the synergistic effects of HCC-targeting and controlled drug release, TAN IIA-loaded GA-PEG-SS-PLGA micelles significantly inhibited tumor growth and increased survival time in a mouse HCC-xenograft model. Collectively, the GA-PEG-SS-PLGA micelles with HCC-targeting and redox-sensitive characters would provide a novel strategy to deliver TAN IIA effectively for HCC therapy.

Preparation and Evaluation of Montelukast Sodium Loaded Solid Lipid Nanoparticles

PubMed Central

Priyanka, K; Sathali, A Abdul Hasan

2012-01-01

Solid lipid nanoparticles (SLNs) are an alternative carrier system used to load the drug for targeting, to improve the bioavailability by increasing its solubility, and protecting the drug from presystemic metabolism. The avoidance of presystemic metabolism is due to the nano-metric size range, so that the liver cannot uptake the drug from the delivery system and is not metabolized by the liver. Montelukast sodium is an anti-asthmatic drug, because of its poor oral bioavailability, presystemic metabolism, and decreased half-life; it was chosen to formulate as the solid lipid nanoparticle (SLN) system by hot homogenization followed by an ultrasonication method, to overcome the above. Compritol ATO 888, stearic acid, and glyceryl monostearate were used as a lipid matrix and polyvinyl alcohol as a surfactant. The prepared formulations have been evaluated for entrapment efficiency, drug content, in vitro drug release, particle size analysis, scanning electron microscopy, Fourier transform-infrared studies (FT-IR), differential scanning calorimetry (DSC), and stability. Particle size analysis revealed that the SLN prepared from the higher melting point lipid showed a larger particle size and with increased carbon chain length of the fatty acids. Entrapment efficiency (EE) was ranging from 42% to 92%. In vitro release studies showed maximum cumulative drug release was obtained for F 1 (59.1%) containing stearic acid, and the lowest was observed for F 18 (28.1%) containing compritol ATO 888 after 12 h and all the formulations followed first-order release kinetics. FT-IR and DSC studies revealed no interaction between drug and lipids. Studies showed that increase in lipid concentration, increased particle size, EE, and maintained the sustained release of drug. Among all, compritol ATO 888 was chosen as the best lipid for formulating SLN because it had high EE and sustained the drug release. PMID:23112531

Reduced phosphorus retention by anoxic bottom sediments after the remediation of an industrial acidified lake area: Indications from P, Al, and Fe sediment fractions.

PubMed

Nürnberg, Gertrud K; Fischer, Rachele; Paterson, Andrew M

2018-06-01

Formerly acidified lakes and watersheds can become more productive when recovering from acidity, especially when exposed to anthropogenic disturbance and increased nutrient loading. Occasional toxic cyanobacterial blooms and other signs of eutrophication have been observed for a decade in lakes located in the Sudbury, Ontario, mining area that was severely affected by acid deposition before the start of smelter emission reductions in the 1970s. Oligotrophic Long Lake and its upstream lakes have been exposed to waste water input and development impacts from the City of Greater Sudbury and likely have a legacy of nutrient enrichment in their sediment. Based on observations from other published studies, we hypothesized that P, which was previously adsorbed by metals liberated during acidification caused by the mining activities, is now being released from the sediment as internal P loading contributing to increased cyanobacteria biomass. Support for this hypothesis includes (1) lake observations of oxygen depletion and hypolimnetic anoxia and slightly elevated hypolimnetic total P concentration and (2) P, Al, and Fe fractionation of two sediment layers (0-5, 5-10 cm), showing elevated concentrations of TP and iron releasable P (BD-fraction), decreased concentrations in fractions associated with Al, and fraction ratios indicating decreased sediment adsorption capacity. The comparison with two moderately enriched lakes within 200 km distance, but never directly affected by mining operations, supports the increasing similarity of Long Lake surficial sediment adsorption capacity with that of unaffected lakes. There is cause for concern that increased eutrophication including the proliferation of cyanobacteria of formerly acidic lakes is wide-spread and occurs wherever recovery coincides with anthropogenic disturbances and physical changes related to climate change. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of changes in intestinal flora and intravascular inflammation and coronary heart disease in obese patients.

PubMed

Li, Xv; Li, Chuantao

2018-05-01

Changes in intestinal flora in obese patients and intravascular C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and coronary heart disease (CHD) were analyzed. A total of 75 cases of obese patients were divided into obesity (OB) alone (n=40) and OB with CHD group (n=35). There was no statistically significant difference in age, sex, pre-existing basic diabetes, history of hypertension, and body mass index (P>0.05). Results showed that total bacterial load of CHD was obviously higher than that of OB group. The uric acid decomposed by intestinal flora (IFUA) and blood uric acid levels in CHD were higher than those in OB group, but the fecal uric acid level was lower than that of OB group (P<0.05). Levels of inflammatory factors in CHD, were significantly higher than those in OB group (P<0.05). Correlation analyses showed that the intestinal flora total load and CRP were positively correlated (r=0.793, P<0.001). Intestinal flora and Gensini score were also positively related to total load (r=0.893, P=0.893). Furthermore, CRP and Gensini score were positively related (r=0.796, P<0.796). IFUA and Gensini score were positively related to (r=0.647, P<0.001). Over-reaction in the flammation system in obese patients may lead to intestinal flora disorder, disturbance and also increased levels of IFUA and inflammatory factors.

Biocompatibility of Gd-Loaded Chitosan-Hyaluronic Acid Nanogels as Contrast Agents for Magnetic Resonance Cancer Imaging

PubMed Central

Gheran, Cecilia Virginia; Rigaux, Guillaume; Callewaert, Maité; Berquand, Alexandre; Chuburu, Françoise; Voicu, Sorina Nicoleta; Dinischiotu, Anca

2018-01-01

Although the research on nanogels incorporating Gd chelates for theranostic applications has grown exponentially in recent years, knowledge about their biocompatibility is limited. We compared the biocompatibility of Gd-loaded hyaluronic acid-chitosan-based nanogels (GdCA⊂CS-TPP/HA) with two chitosan concentrations (2.5 and 1.5 mg·mL−1 respectively) using SVEC4-10 murine lymph node endothelial cells. The sulforhodamine B method and released lactate dehydrogenase (LDH) activity were used as cell viability tests. Reactive oxygen species (ROS), reduced glutathione (GSH) and malondialdehyde (MDA) were measured by spectrophotometric and fluorimetric methods. Nrf-2 protein expression was evaluated by Western blot analysis and genotoxicity by alkaline comet assay. After 24 h, the cells viability was not affected by all types and doses of nanogels. The increase of ROS induced a low decrease of GSH concentration and a time-dependent raise of MDA one was produced by citric GdDOTA⊂CS-TPP/HA with a chitosan concentration of 1.5 mg·mL−1, at the highest dose applied. None of the tested nanogels induced changes in Nrf-2 protein expression. A slight but significant genotoxic effect was caused only by citric GdDOTA⊂CS-TPP/HA where CS concentration was 1.5 mg·mL−1. Our results showed a better biocompatibility with lymph node endothelial cells for Gd-loaded hyaluronic acid-chitosan based nanogels with a concentration in chitosan of 2.5 mg·mL−1. PMID:29597306

Synthesis of antimicrobial Nisin-phosphorylated soybean protein isolate/poly(L-lactic acid)/ZrO2 membranes.

PubMed

Jiang, Suwei; Wang, Hualin; Chu, Chenjiang; Ma, Xingkong; Sun, Min; Jiang, Shaotong

2015-01-01

Electrospinning technique was used to fabricate the model drug Nisin loaded phosphorylated soybean protein isolate/poly(l-lactic acid)/zirconium dioxide (Nisin-PSPI/PLLA/ZrO2) nanofibrous membranes. The average diameter of drug carrier PSPI/PLLA/ZrO2 nanofibers increased with the increase of content PSPI and some spindle-shape beads appeared when PSPI content reached 25 wt%. The loading dosage of Nisin caused no significant changes in the size and morphology of nanofibers when Nisin content was below 9 wt%. There existed hydrogen and Zr-O-C bonds among PSPI, PLLA and ZrO2 units, and the crystalline of PLLA matrix decreased owning to the introducing of PSPI and ZrO2 units. Moreover, the water absorption capability and degradation rate of PSPI/PLLA/ZrO2 nanofibrous membranes increased with increasing PSPI content. The antimicrobial activity and release experimental results showed that Nisin-PSPI/PLLA/ZrO2 nanofibrous membranes displayed well controlled release and better antimicrobial activity against Staphylococcus aureus (S. aureus), and the Nisin release from the medicated nanofibers could be described by Fickian diffusion model. The Nisin-PSPI/PLLA/ZrO2 nanofibrous membranes may have potential as a new nanofibrous membrane in drug delivery, food active packaging and wound dressing. Copyright © 2014 Elsevier B.V. All rights reserved.

High Dietary Acid Load Predicts ESRD among Adults with CKD

PubMed Central

Crews, Deidra C.; Wesson, Donald E.; Tilea, Anca M.; Saran, Rajiv; Ríos-Burrows, Nilka; Williams, Desmond E.; Powe, Neil R.

2015-01-01

Small clinical trials have shown that a reduction in dietary acid load (DAL) improves kidney injury and slows kidney function decline; however, the relationship between DAL and risk of ESRD in a population-based cohort with CKD remains unexamined. We examined the association between DAL, quantified by net acid excretion (NAEes), and progression to ESRD in a nationally representative sample of adults in the United States. Among 1486 adults with CKD age≥20 years enrolled in the National Health and Nutrition Examination Survey III, DAL was determined by 24-h dietary recall questionnaire. The development of ESRD was ascertained over a median 14.2 years of follow-up through linkage with the Medicare ESRD Registry. We used the Fine–Gray competing risks method to estimate the association of high, medium, and low DAL with ESRD after adjusting for demographics, nutritional factors, clinical factors, and kidney function/damage markers and accounting for intervening mortality events. In total, 311 (20.9%) participants developed ESRD. Higher levels of DAL were associated with increased risk of ESRD; relative hazards (95% confidence interval) were 3.04 (1.58 to 5.86) for the highest tertile and 1.81 (0.89 to 3.68) for the middle tertile compared with the lowest tertile in the fully adjusted model. The risk of ESRD associated with DAL tertiles increased as eGFR decreased (P trend=0.001). Among participants with albuminuria, high DAL was strongly associated with ESRD risk (P trend=0.03). In conclusion, high DAL in persons with CKD is independently associated with increased risk of ESRD in a nationally representative population. PMID:25677388

Potassium bicarbonate supplementation lowers bone turnover and calcium excretion in older men and women a randomized dose-finding trial

USDA-ARS?s Scientific Manuscript database

The acid load accompanying modern diets may have adverse effects on bone and muscle metabolism. Treatment with alkaline salts of potassium can neutralize the acid load, but the optimal amount of alkali is not established. Our objective was to determine the effectiveness of two doses of potassium bic...

In vitro antimicrobial activity of solution blow spun poly(lactic acid)/ polyvinylpyrrolidone nanofibers loaded with Copaiba (Copaifera sp.) oil

USDA-ARS?s Scientific Manuscript database

In this study poly(lactic acid)(PLA) and polyvinylpyrrolidone (PVP) micro and nanofibers mats loaded with copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/ PVP blends contain...

Advanced zinc-doped adhesives for high performance at the resin-carious dentin interface.

PubMed

Toledano, Manuel; Osorio, Raquel; Osorio, Estrella; García-Godoy, Franklin; Toledano-Osorio, Manuel; Aguilera, Fátima S

2016-09-01

The purpose of this study was to evaluate the remineralization ability of an etch-and-rinse Zn-doped resin applied on caries-affected dentin (CAD). CAD surfaces were subjected to: (i) 37% phosphoric acid (PA) or (ii) 0.5M ethylenediaminetetraacetic acid (EDTA). 10wt% ZnO nanoparticles or 2wt% ZnCl2 were added into the adhesive Single Bond (SB), to create the following groups: PA+SB, PA+SB-ZnO, PA+SB-ZnCl2, EDTA+SB, EDTA+SB-ZnO, EDTA+SB-ZnCl2. Bonded interfaces were submitted to mechanical loading or stored during 24h. Remineralization of the bonded interfaces was studied by AFM nano-indentation (hardness and Young׳s modulus), Raman spectroscopy [mapping with principal component analysis (PCA), and hierarchical cluster analysis (HCA)] and Masson׳s trichrome staining technique. Dentin samples treated with PA+SB-ZnO attained the highest values of nano-mechanical properties. Load cycling increased both mineralization and crystallographic maturity at the interface; this effect was specially noticed when using ZnCl2-doped resin in EDTA-treated carious dentin. Crosslinking attained higher frequencies indicating better conformation and organization of collagen in specimens treated with PA+SB-ZnO, after load cycling. Trichrome staining technique depicted a deeper demineralized dentin fringe that became reduced after loading, and it was not observable in EDTA+SB groups. Multivariate analysis confirmed de homogenizing effect of load cycling in the percentage of variances, traces of centroids and distribution of clusters, especially in specimens treated with EDTA+SB-ZnCl2. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photocatalytic removal of 2,4-dichlorophenoxyacetic acid herbicide on copper oxide/titanium dioxide prepared by co-precipitation method

NASA Astrophysics Data System (ADS)

Lee, Shu Chin; Hasan, Norhasnita; Lintang, Hendrik O.; Shamsuddin, Mustaffa; Yuliati, Leny

2016-02-01

In this work, suppression of the charge recombination on the titanium dioxide (TiO2) was reported by the addition of copper oxide (CuO), which led to a higher activity of TiO2 for removal of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide. A series of CuO/TiO2 with CuO loadings of 0.1-1 wt% was prepared through a co-precipitation method. X-ray diffraction patterns revealed that the presence of CuO could not be detected as the low loading amount of CuO might have good dispersion on the surface of TiO2. Diffuse reflectance UV-visible spectra suggested that low loading amount of CuO did not influence the optical property of TiO2. Fluorescence spectroscopy revealed that TiO2 possessed a dominant emission peak of 407 nm at an excitation wavelength of 218 nm. The increasing loading amount of CuO decreased the emission intensity of TiO2, suggesting the successful reduction of charge recombination. After irradiation under UV light for 1 h, CuO(0.1 wt%)/TiO2 gave the highest percentage removal of the herbicide among the samples. The optimum loading amount of CuOmight improve the charge separation and reduce the electron-hole recombination on TiO2 without blocking the active sites, thus leading to the improved photocatalytic activity. This work showed that CuO/TiO2 is a potential photocatalyst for environmental remediation.

Polymersomes from dual responsive block copolymers: drug encapsulation by heating and acid-triggered release.

PubMed

Qiao, Zeng-Ying; Ji, Ran; Huang, Xiao-Nan; Du, Fu-Sheng; Zhang, Rui; Liang, De-Hai; Li, Zi-Chen

2013-05-13

A series of well-defined thermoresponsive diblock copolymers (PEO45-b-PtNEAn, n=22, 44, 63, 91, 172) were prepared by the atom transfer radical polymerization of trans-N-(2-ethoxy-1,3-dioxan-5-yl) acrylamide (tNEA) using a poly(ethylene oxide) (PEO45) macroinitiator. All copolymers are water-soluble at low temperature, but upon quickly heating to 37 °C, laser light scattering (LLS) and transmission electron microscopy (TEM) characterizations indicate that these copolymers self-assemble into aggregates with different morphologies depending on the chain length of PtNEA and the polymer concentration; the morphologies gradually evolved from spherical solid nanoparticles to a polymersome as the degree of polymerization ("n") of PtNEA block increased from 22 to 172, with the formation of clusters with rod-like structure at the intermediate PtNEA length. Both the spherical nanoparticle and the polymersome are stable at physiological pH but susceptible to the mildly acidic medium. Acid-triggered hydrolysis behaviors of the aggregates were investigated by LLS, Nile red fluorescence, TEM, and (1)H NMR spectroscopy. The results revealed that the spherical nanoparticles formed from PEO45-b-PtNEA44 dissociated faster than the polymersomes of PEO45-b-PtNEA172, and both aggregates showed an enhanced hydrolysis under acidic conditions. Both the spherical nanoparticle and polymersome are able to efficiently load the hydrophobic doxorubicin (DOX), and water-soluble fluorescein isothiocyanate-lysozyme (FITC-Lys) can be conveniently encapsulated into the polymersome without using any organic solvent. Moreover, FITC-Lys and DOX could be coloaded in the polymersome. The drugs loaded either in the polymersome or in the spherical nanoparticle could be released by acid triggering. Finally, the DOX-loaded assemblies display concentration-dependent cytotoxicity to HepG2 cells, while the copolymers themselves are nontoxic.

Simultaneous saccharification and fermentation of acid-pretreated rapeseed meal for succinic acid production using Actinobacillus succinogenes.

PubMed

Chen, Kequan; Zhang, Han; Miao, Yelian; Wei, Ping; Chen, Jieyu

2011-04-07

Rapeseed meal was evaluated for succinic acid production by simultaneous saccharification and fermentation using Actinobacillus succinogenes ATCC 55618. Diluted sulfuric acid pretreatment and subsequent hydrolysis with pectinase was used to release sugars from rapeseed meal. The effects of culture pH, pectinase loading and yeast extract concentration on succinic acid production were investigated. When simultaneous saccharification and fermentation of diluted acid pretreated rapeseed meal with a dry matter content of 12.5% (w/v) was performed at pH 6.4 and a pectinase loading of 2% (w/w, on dry matter) without supplementation of yeast extract, a succinic acid concentration of 15.5 g/L was obtained at a yield of 12.4 g/100g dry matter. Fed-batch simultaneous saccharification and fermentation was carried out with supplementation of concentrated pretreated rapeseed meal and pectinase at 18 and 28 h to yield a final dry matter content of 20.5% and pectinase loading of 2%, with the succinic acid concentration enhanced to 23.4 g/L at a yield of 11.5 g/100g dry matter and a productivity of 0.33 g/(Lh). This study suggests that rapeseed meal may be an alternative substrate for the efficient production of succinic acid by A. succinogenes without requiring nitrogen source supplementation. Copyright © 2011 Elsevier Inc. All rights reserved.

Usnic Acid, a Natural Antimicrobial Agent Able To Inhibit Bacterial Biofilm Formation on Polymer Surfaces

PubMed Central

Francolini, I.; Norris, P.; Piozzi, A.; Donelli, G.; Stoodley, P.

2004-01-01

In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways. PMID:15504865

Designed Synthesis of Lipid-Coated Polyacrylic Acid/Calcium Phosphate Nanoparticles as Dual pH-Responsive Drug-Delivery Vehicles for Cancer Chemotherapy.

PubMed

Wang, Xin; Zhang, Manjie; Zhang, Lingyu; Li, Lu; Li, Shengnan; Wang, Chungang; Su, Zhongmin; Yuan, Yue; Pan, Weisan

2017-05-11

Herein, we report a facile strategy to prepare supported lipid-bilayer-coated polyacrylic acid/calcium phosphate nanoparticles (designated as PAA/CaP@SLB NPs) as a new dual pH-responsive drug-delivery platform for cancer chemotherapy. The synthesized PAA/CaP NPs exhibited both a high payload of doxorubicin (DOX) and dual pH-responsive drug-release properties. Additionally, the coated lipid bilayer had the ability to enhance the cellular uptake of PAA/CaP NPs without affecting the pH-responsive drug release. Moreover, the blank PAA/CaP@SLB NPs exhibited excellent biocompatibility and the DOX-loaded PAA/CaP@SLB NPs markedly increased the cellular accumulation of DOX and its cytotoxic effects on HepG-2 cells. Furthermore, when used to evaluate the in vivo therapeutic efficacy in mice with the hepatocarcinoma cell line (H-22), the DOX-loaded PAA/CaP@SLB NPs exhibited superior inhibition of tumor growth compared with the free DOX group. Thus, PAA/CaP@SLB NPs are a promising drug-delivery vehicle to increase the therapeutic efficacy of anticancer drugs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of folate-modified pullulan acetate nanoparticles for tumor-targeted drug delivery.

PubMed

Zhang, Hui-zhu; Li, Xue-min; Gao, Fu-ping; Liu, Ling-rong; Zhou, Zhi-min; Zhang, Qi-qing

2010-01-01

The purpose of this work was to develop a novel nano-carrier with targeting property to tumor. In this study, pullulan acetate (PA) was synthesized by the acetylation of pullulan to simplify the preparation technique of nanoparticles. Folic acid (FA) was conjugated to PA in order to improve the cancer-targeting activity. The products were characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Epirubicin-loaded nanoparticles were prepared by a solvent diffusion method. The loading efficiencies and EPI content increased with the amount of triethylamine (TEA) increasing in some degree. FPA nanoparticles could incorporate more epirubicin than PA nanoparticles. The folate-modified PA nanoparticles (FPA/EPI NPs) exhibited faster drug release than PA nanoparticles (PA/EPI NPs) in vitro. Confocal image analysis and flow cytometry test revealed that FPA/EPI NPs exhibited a greater extent of cellular uptake than PA/EPI NPs against KB cells over-expressing folate receptors on the surface. FPA/EPI NPs also showed higher cytotoxicity than PA/EPI NPs. The cytotoxic effect of FPA/EPI NPs to KB cells was inhibited by an excess amount of folic acid, suggesting that the binding and/or uptake were mediated by the folate receptor.

Increasing glucose load while maintaining normoglycemia does not evoke neuronal damage in prolonged critically ill rabbits.

PubMed

Sonneville, Romain; den Hertog, Heleen M; Derde, Sarah; Güiza, Fabian; Derese, Inge; Van den Berghe, Greet; Vanhorebeek, Ilse

2013-12-01

Preventing severe hyperglycemia with insulin reduced the neuropathological alterations in frontal cortex during critical illness. We investigated the impact of increasing glucose load under normoglycemia on neurons and glial cells. Hyperinflammatory critically ill rabbits were randomized to fasting or combined parenteral nutrition containing progressively increasing amounts of glucose (low, intermediate, high) within the physiological range but with a similar amount of amino acids and lipids. In all groups, normoglycemia was maintained with insulin. On day 7, we studied the neuropathological alterations in frontal cortex neurons, astrocytes and microglia, and MnSOD as marker of oxidative stress. The percentage of damaged neurons was comparable among all critically ill and healthy rabbits. Critical illness induced an overall 1.8-fold increase in astrocyte density and activation status, largely irrespective of the nutritional intake. The percentage of microglia activation in critically ill rabbits was comparable with that in healthy rabbits, irrespective of glucose load. Likewise, MnSOD expression was comparable in critically ill and healthy rabbits without any clear impact of the nutritional interventions. During prolonged critical illness, increasing intravenous glucose infusion while strictly maintaining normoglycemia appeared safe for neuronal integrity and did not substantially affect glial cells in frontal cortex. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

In vivo and in vitro binding of fatty acids to genetic variants of human serum albumin.

PubMed

Kragh-Hansen, U; Nielsen, H; Pedersen, A O

1995-01-01

The effect of genetic variation on the fatty-acid binding properties of human serum albumin was studied by two methods involving the use of sequenced albumin variants isolated from bisalbuminaemic persons. First, the amount of total fatty acid and of several individuals fatty acids bound to eighteen different variants and to their normal counterpart (Alb A) were determined by a gas-chromatographic micromethod. Pronounced effects on total fatty acid binding were found for the glycosylated variants Alb Redhill (modified in domain II) and Alb Casebrook (domain III) in which cases a 1.7- and 8.6-fold increment, respectively, was found. By contrast, Alb Malm0 (glycosylated in domain I) carried the same amount of fatty acid as Alb A. The fatty acid loads on three chain-termination variants were normal. Finally, eight albumins with single amino-acid substitutions bound normal amounts of fatty acid, whereas one bound increased (1.7-fold) and three albumins bound diminished amounts (0.5-0.6-fold). Information on nineteen individual fatty acids was also obtained. It was possible, based on the type of changes in their relative amounts, to group the fatty acids as follows: (a) = C6:0 - C14:0, (b) = C15:0 - C18:0, (c) = C16:1 - C18:1, and (d) a group composed of essential and conditionally essential fatty acids. For nine variants, in most cases modified in domain III, large changes in one or more of these groups were observed. The changes were not related to any changes in total fatty acid load. Second, the binding of laurate, as a representative of the group (a) fatty acids, to delipidated albumin preparations was studied at pH 7.4 by a kinetic dialysis technique. The first stoichiometric association constant for binding to Alb Redhill (0.7-fold) and Alb Casebrook (0.6-fold) was diminished as compared with binding to their corresponding Alb A, whereas binding to one chain-termination variant and three single amino-acid substitutions were all unaffected by the mutation.

Control of rectal gland secretion by blood acid-base status in the intact dogfish shark (Squalus acanthias).

PubMed

Wood, Chris M; Munger, R Stephen; Thompson, Jill; Shuttleworth, Trevor J

2007-05-14

In order to address the possible role of blood acid-base status in controlling the rectal gland, dogfish were fitted with indwelling arterial catheters for blood sampling and rectal gland catheters for secretion collection. In intact, unanaesthetized animals, isosmotic volume loading with 500 mmol L-1 NaCl at a rate of 15 mL kg-1 h-1 produced a brisk, stable rectal gland secretion flow of about 4 mL kg-1 h-1. Secretion composition (500 mmol L-1 Na+ and Cl-; 5 mmol L-1 K+; <1 mmol L-1 Ca2+, Mg2+, SO(4)2-, or phosphate) was almost identical to that of the infusate with a pH of about 7.2, HCO3- mmol L-1<1 mmol L-1 and a PCO2 (1 Torr) close to PaCO2. Experimental treatments superimposed on the infusion caused the expected disturbances in systemic acid-base status: respiratory acidosis by exposure to high environmental PCO2, metabolic acidosis by infusion of HCl, and metabolic alkalosis by infusion of NaHCO3. Secretion flow decreased markedly with acidosis and increased with alkalosis, in a linear relationship with extracellular pH. Secretion composition did not change, apart from alterations in its acid-base status, and made negligible contribution to overall acid-base balance. An adaptive control of rectal gland secretion by systemic acid-base status is postulated-stimulation by the "alkaline tide" accompanying the volume load of feeding and inhibition by the metabolic acidosis accompanying the volume contraction of exercise.

Mycobacterium tuberculosis Uses Host Triacylglycerol to Accumulate Lipid Droplets and Acquires a Dormancy-Like Phenotype in Lipid-Loaded Macrophages

PubMed Central

Daniel, Jaiyanth; Sirakova, Tatiana D.; Kolattukudy, Pappachan E.

2011-01-01

Two billion people are latently infected with Mycobacterium tuberculosis (Mtb). Mtb-infected macrophages are likely to be sequestered inside the hypoxic environments of the granuloma and differentiate into lipid-loaded macrophages that contain triacylglycerol (TAG)-filled lipid droplets which may provide a fatty acid-rich host environment for Mtb. We report here that human peripheral blood monocyte-derived macrophages and THP-1 derived macrophages incubated under hypoxia accumulate Oil Red O-staining lipid droplets containing TAG. Inside such hypoxic, lipid-loaded macrophages, nearly half the Mtb population developed phenotypic tolerance to isoniazid, lost acid-fast staining and accumulated intracellular lipid droplets. Dual-isotope labeling of macrophage TAG revealed that Mtb inside the lipid-loaded macrophages imports fatty acids derived from host TAG and incorporates them intact into Mtb TAG. The fatty acid composition of host and Mtb TAG were nearly identical suggesting that Mtb utilizes host TAG to accumulate intracellular TAG. Utilization of host TAG by Mtb for lipid droplet synthesis was confirmed when fluorescent fatty acid-labeled host TAG was utilized to accumulate fluorescent lipid droplets inside the pathogen. Deletion of the Mtb triacylglycerol synthase 1 (tgs1) gene resulted in a drastic decrease but not a complete loss in both radiolabeled and fluorescent TAG accumulation by Mtb suggesting that the TAG that accumulates within Mtb is generated mainly by the incorporation of fatty acids released from host TAG. We show direct evidence for the utilization of the fatty acids from host TAG for lipid metabolism inside Mtb. Taqman real-time PCR measurements revealed that the mycobacterial genes dosR, hspX, icl1, tgs1 and lipY were up-regulated in Mtb within hypoxic lipid loaded macrophages along with other Mtb genes known to be associated with dormancy and lipid metabolism. PMID:21731490

Enhanced anti-cancer efficacy to cancer cells by doxorubicin loaded water-soluble amino acid-modified β-cyclodextrin platinum complexes.

PubMed

Zhao, Mei-Xia; Zhao, Meng; Zeng, Er-Zao; Li, Yang; Li, Jin-Ming; Cao, Qian; Tan, Cai-Ping; Ji, Liang-Nian; Mao, Zong-Wan

2014-08-01

The effective targeted delivery of insoluble anticancer drugs to increase the intracellular drug concentration has become a focus in cancer therapy. In this system, two water-soluble amino acid-modified β-cyclodextrin (β-CD) platinum complexes were reported. They showed preferable binding ability to DNA and effective inhibition to cancer cells, and they could bind and unwind pBR322 DNA in a manner which was similar to cisplatin. Besides, our platinum complexes could effectively deliver the anticancer drug doxorubicin (Dox) into cells and had higher cell inhibition ratio, but less toxicity on the normal cells, compared with cancer cells. In this combination system, Dox was encapsulated into the hydrophobic cavities of β-CD at the optimum molar ratio of 1:1, which were validated by UV-visible (UV-vis) absorption spectroscopy, fluorescence spectroscopy and MTT experiments. Moreover, the combination system had higher cell inhibition ratio than free Dox and amino acid-modified β-CD platinum complexes, and the results of high content screening (HCS) showed that Dox-loaded amino acid-modified β-CD platinum complexes could permeate the cell membrane and enter cells, suggesting the efficient transport of Dox across the membranes with the aid of the β-CD. We expect that the amino acid-modified β-CD platinum complexes will deliver the antitumor drug Dox to enhance intracellular drug accumulation and such combination system showed great potential as an antitumor drug. Copyright © 2014 Elsevier Inc. All rights reserved.

A micropuncture study of the effect of parathyroid hormone on renal bicarbonate reabsorption.

PubMed Central

Bank, N; Aynediian, H S

1976-01-01

Renal micropuncture and clearance experiments were carried out in rats to study the effect of parathyroid hormone (PTH) on renal tubular HCO-/3 reabsorption. The rats were studied during an initial period of parathyroid deficiency (acute thyroidparathyroidectomy, TPTX) and during infusion of large amounts of bovine PTH. Under normal acid-base conditions, PTH administration to TPTX rats caused a significant rise in proximal tubular fluid HCO-/3 concentration (TFHCO-/3), a decrease in fluid reabsorption, and a fall in proximal HCO-/3 reabsorption from 94.0 to 88.2% (P less than 0.01). In control experiments with mannitol infusion, a comparable reduction in proximal fluid reabsorption occurred without any significant effect on intraluminal HCO-/3 concentration. During acute intravenous HCO-/3 loading, PTH inhibited proximal HCO-/3 reabsorption. However, no change in whole kidney HCO-/3 reabsorption was observed in these experiments or in the animals studied under normal acid-base conditions. The findings are consistent with the view that PTH inhibits proximal tubular HCO-/3 reabsorption with normal or high filtered loads of HCO-/3, but distal segments of the nephron are able to reabsorb the excess delivered from the proximal tubule. Measurements of urinary ammonium and titratable acid indicate that net acid excretion (NH+/4 + TA -- HCO-/3) increases significantly after PTH administration. These results do not provide support for the view that PTH excess causes metabolic acidosis by reducing renal acid excretion. PMID:956369

In vitro wear rates of materials under different loads and varying pH.

PubMed

Shabanian, Mitra; Richards, Lindsay C

2002-06-01

Despite the need for information about the wear characteristics of restorative materials, there have been few systemic studies of the factors that influence the rate of material wear. This study compared the wear rates of enamel and 3 tooth-colored restorative materials under different loads (0, 3.2, 6.7, and 9.95 kg) and pH levels (1.2, 3.3, and 7.0). An electromechanical tooth wear machine was used so that standard restorations representing 3 materials could be worn by opposing enamel under controlled conditions. The wear rates of enamel, composite (Z100), a conventional glass ionomer cement (Fuji IX), and a resin-modified glass ionomer cement (Fuji II LC) were compared at a range of loads (0 to 9.95 kg) and pH levels (1.2 to 7.0) and also at different sites across each restoration. Ten specimens were randomly assigned to each experimental group. Wear assessment was performed with a modified light microscope to quantify the height changes at defined points across wear facets. Four-way analysis of variance was used to compare wear rates among materials, pH levels, loads, and sites. Post-hoc t tests identified significant differences between specific pairs of experimental conditions (P<.05). The wear rates of enamel and the other test materials varied significantly with pH (P<.0001), load (P<.0001), and type of material (P<.0001). Enamel wear was influenced most by varied pH, whereas the composite was least affected by acid. The conventional glass ionomer cement was more susceptible than the composite to the effects of varied pH; the acid susceptibility of the resin-modified glass ionomer cement was generally between that of the composite and conventional glass ionomer cement. Enamel and the conventional glass ionomer cement were affected similarly by load. The composite was more resistant than the conventional glass ionomer cement to wear at higher loads; the resin-modified glass ionomer cement exhibited intermediate load resistance. Within the limitations of this study, the 3 test materials were more resistant than enamel to acid, with the composite demonstrating the lowest susceptibility to acid. The acid- and load-resistance of the resin-modified glass ionomer cement was consistently less than that of the composite and greater than that of the conventional glass ionomer cement.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

PubMed

Pennanen; Fritze; Vanhala; Kiikkila; Neuvonen; Baath

1998-06-01

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.

Ascorbic Acid Prevents VEGF-induced Increases in Endothelial Barrier Permeability

PubMed Central

Ulker, Esad; Parker, William H.; Raj, Amita; Qu, Zhi-chao; May, James M.

2015-01-01

Vascular endothelial growth factor (VEGF) increases endothelial barrier permeability, an effect that may contribute to macular edema in diabetic retinopathy. Since vitamin C, or ascorbic acid, can tighten the endothelial permeability barrier, we examined whether it could prevent the increase in permeability due to VEGF in human umbilical vein endothelial cells (HUVECs). As previously observed, VEGF increased HUVEC permeability to radiolabeled inulin within 60 min in a concentration-dependent manner. Loading the cells with increasing concentrations of ascorbate progressively prevented the leakage caused by 100 ng/ml VEGF, with a significant inhibition at 13 μM and complete inhibition at 50 μM. Loading cells with 100 μM ascorbate also decreased basal generation of reactive oxygen species and prevented the increase caused by both 100 ng/ml VEGF. VEGF treatment decreased intracellular ascorbate by 25%, thus linking ascorbate oxidation to its prevention of VEGF-induced barrier leakage. The latter was blocked by treating the cells with 60 μM L-NAME (but not D-NAME) as well as by 30 μM sepiapterin, a precursor of tetrahydrobiopterin that is required for proper function of endothelial nitric oxide synthase (eNOS). These findings suggest that VEGF-induced barrier leakage uncouples eNOS. Ascorbate inhibition of the VEGF effect could thus be due either to scavenging superoxide or to peroxynitrite generated by the uncoupled eNOS, or more likely to its ability to recycle tetrahydrobiopterin, thus avoiding enzyme uncoupling in the first place. Ascorbate prevention of VEGF-induced increases in endothelial permeability opens the possibility that its repletion could benefit diabetic macular edema. PMID:26590088

Integrated Solvent Design for CO 2 Capture and Viscosity Tuning

DOE PAGES

Cantu, David C.; Malhotra, Deepika; Koech, Phillip K.; ...

2017-08-18

We present novel design strategies for reduced viscosity single-component, water-lean CO 2 capture organic solvent systems. Through molecular simulation, we identify the main molecular-level descriptor that influences bulk solvent viscosity. Upon loading, a zwitterionic structure forms with a small activation energy of ca 16 kJ/mol and a small stabilization of ca 6 kJ/mol. Viscosity increases exponentially with CO 2 loading due to hydrogen-bonding between neighboring Zwitterions. We find that molecular structures that promote internal hydrogen bonding (within the same molecule) and suppress interactions with neighboring molecules have low viscosities. In addition, tuning the acid/base properties leads to a shift ofmore » the equilibrium toward a non-charged (acid) form that further reduces the viscosity. Here, based on the above structural criteria, a reduced order model is also presented that allows for the quick screening of large compound libraries and down selection of promising candidates for synthesis and testing.« less

Ionic Liquid Fuels for Chemical Propulsion

DTIC Science & Technology

2014-11-20

researchers seeking hypergolic fuels have limited themselves to the extremely toxic and corrosive nitric acid solutions. While important questions remain...storable oxidizer (N204 , nitric acid ) have been synthesized and demonstrated. The bipropellant fuels are based upon salts containing dicyanamide or...20-30% nanoparticle loading but decreases between 10-20%, perhaps indicating an optimal loading concentration for these nanoparticles between 10-20

Optimization of levulinic acid from lignocellulosic biomass using a new hybrid catalyst.

PubMed

Ya'aini, Nazlina; Amin, Nor Aishah Saidina; Asmadi, Mohd

2012-07-01

Conversion of glucose, empty fruit bunch (efb) and kenaf to levulinic acid over a new hybrid catalyst has been investigated in this study. The characterization and catalytic performance results revealed that the physico-chemical properties of the new hybrid catalyst comprised of chromium chloride and HY zeolite increased the levulinic acid production from glucose compared to the parent catalysts. Optimization of the glucose conversion process using two level full factorial designs (2(3)) with two center points reported 55.2% of levulinic acid yield at 145.2 °C, 146.7 min and 12.0% of reaction temperature, reaction time and catalyst loading, respectively. Subsequently, the potential of efb and kenaf for producing levulinic acid at the optimum conditions was established after 53.2% and 66.1% of efficiencies were reported. The observation suggests that the hybrid catalyst has a potential to be used in biomass conversion to levulinic acid. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of yoga on the autonomic nervous system, gamma-aminobutyric-acid, and allostasis in epilepsy, depression, and post-traumatic stress disorder.

PubMed

Streeter, C C; Gerbarg, P L; Saper, R B; Ciraulo, D A; Brown, R P

2012-05-01

A theory is proposed to explain the benefits of yoga practices in diverse, frequently comorbid medical conditions based on the concept that yoga practices reduce allostatic load in stress response systems such that optimal homeostasis is restored. It is hypothesized that stress induces (1) imbalance of the autonomic nervous system (ANS) with decreased parasympathetic nervous system (PNS) and increased sympathetic nervous system (SNS) activity, (2) underactivity of the gamma amino-butyric acid (GABA) system, the primary inhibitory neurotransmitter system, and (3) increased allostatic load. It is further hypothesized that yoga-based practices (4) correct underactivity of the PNS and GABA systems in part through stimulation of the vagus nerves, the main peripheral pathway of the PNS, and (5) reduce allostatic load. Depression, epilepsy, post traumatic stress disorder (PTSD), and chronic pain exemplify medical conditions that are exacerbated by stress, have low heart rate variability (HRV) and low GABAergic activity, respond to pharmacologic agents that increase activity of the GABA system, and show symptom improvement in response to yoga-based interventions. The observation that treatment resistant cases of epilepsy and depression respond to vagal nerve stimulation corroborates the need to correct PNS underactivity as part of a successful treatment plan in some cases. According to the proposed theory, the decreased PNS and GABAergic activity that underlies stress-related disorders can be corrected by yoga practices resulting in amelioration of disease symptoms. This has far-reaching implications for the integration of yoga-based practices in the treatment of a broad array of disorders exacerbated by stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

Acid-functionalized nanoparticles for biomass hydrolysis

NASA Astrophysics Data System (ADS)

Pena Duque, Leidy Eugenia

Cellulosic ethanol is a renewable source of energy. Lignocellulosic biomass is a complex material composed mainly of cellulose, hemicellulose, and lignin. Biomass pretreatment is a required step to make sugar polymers liable to hydrolysis. Mineral acids are commonly used for biomass pretreatment. Using acid catalysts that can be recovered and reused could make the process economically more attractive. The overall goal of this dissertation is the development of a recyclable nanocatalyst for the hydrolysis of biomass sugars. Cobalt iron oxide nanoparticles (CoFe2O4) were synthesized to provide a magnetic core that could be separated from reaction using a magnetic field and modified to carry acid functional groups. X-ray diffraction (XRD) confirmed the crystal structure was that of cobalt spinel ferrite. CoFe2O4 were covered with silica which served as linker for the acid functions. Silica-coated nanoparticles were functionalized with three different acid functions: perfluoropropyl-sulfonic acid, carboxylic acid, and propyl-sulfonic acid. Transmission electron microscope (TEM) images were analyzed to obtain particle size distributions of the nanoparticles. Total carbon, nitrogen, and sulfur were quantified using an elemental analyzer. Fourier transform infra-red spectra confirmed the presence of sulfonic and carboxylic acid functions and ion-exchange titrations accounted for the total amount of catalytic acid sites per nanoparticle mass. These nanoparticles were evaluated for their performance to hydrolyze the beta-1,4 glycosidic bond of the cellobiose molecule. Propyl-sulfonic (PS) and perfluoropropyl-sulfonic (PFS) acid functionalized nanoparticles catalyzed the hydrolysis of cellobiose significantly better than the control. PS and PFS were also evaluated for their capacity to solubilize wheat straw hemicelluloses and performed better than the control. Although PFS nanoparticles were stronger acid catalysts, the acid functions leached out of the nanoparticle during the catalytic reactions. PS nanoparticles were further evaluated for the pretreatment of corn stover in order to increase digestibility of the biomass. The pretreatment was carried out at three different catalyst load and temperature levels. At 180°C, the total glucose yield was linearly correlated to the catalyst load. A maximum glucose yield of 90% and 58% of the hemicellulose sugars were obtained at this temperature.

Tadalafil-loaded nanostructured lipid carriers using permeation enhancers.

PubMed

Baek, Jong-Suep; Pham, Cuong Viet; Myung, Chang-Seon; Cho, Cheong-Weon

2015-11-30

Tadalafil is a phosphodiesterase-5 inhibitor indicated for the treatment of erectile dysfunction. In this study, we prepared and evaluated transdermal nanostructured lipid carriers (NLC) to improve the skin permeability of tadalafil. Tadalafil-loaded NLC dispersions were prepared using glyceryl monostearate as a solid lipid, oleic acid as a liquid lipid, and Tween 80 as a surfactant. We characterized the dispersions according to particle size, polydispersity index, zeta potential, encapsulation efficiency, and transmission electron microscopy. In vitro skin permeation studies were carried out using Franz diffusion cells, and cytotoxicity was examined using HaCaT keratinocyte cell lines. Tadalafil skin permeability increased for all tadalafil-loaded NLC formulations. The tadalafil-loaded NLC dispersion with ethanol and limonene as skin permeation enhancers exhibited the highest flux (∼4.8-fold) compared to that observed with tadalafil solution alone. Furthermore, a tadalafil-loaded NLC gel with selected permeation enhancers showed tolerance against toxicity in HaCaT cells. These results suggest that the NLC formulations with ethanol and limonene as skin permeation enhancers could be a promising dermal delivery carrier for tadalafil. Copyright © 2015 Elsevier B.V. All rights reserved.

ACHIEVING THE PROMISE OF THERAPEUTIC EXTRACELLULAR VESICLES: THE DEVIL IS IN DETAILS OF THERAPEUTIC LOADING

PubMed Central

Sutaria, Dhruvitkumar S.; Badawi, Mohamed; Phelps, Mitch A.; Schmittgen, Thomas D.

2017-01-01

Extracellular vesicles (EVs) represent a class of cell secreted organelles which naturally contain biomolecular cargo such as miRNA, mRNA and proteins. EVs mediate intercellular communication, enabling the transfer of functional nucleic acids from the cell of origin to the recipient cells. In addition, EVs make an attractive delivery vehicle for therapeutics owing to their increased stability in circulation, biocompatibility, low immunogenicity and toxicity profiles. EVs can also be engineered to display targeting moieties on their surfaces which enables targeting to desired tissues, organs or cells. While much has been learned on the role of EVs as cell communicators, the field of therapeutic EV application is currently under development. Critical to the future success of EV delivery system is the description of methods by which therapeutics can be successfully and efficiently loaded within the EVs. Two methods of loading of EVs with therapeutic cargo exist, endogenous and exogenous loading. We have therefore focused this review on describing the various published approaches for loading EVs with therapeutics. PMID:28315083

pH-Responsive biodegradable polymeric micelles with anchors to interface magnetic nanoparticles for MR imaging in detection of cerebral ischemic area

NASA Astrophysics Data System (ADS)

Yang, Hong Yu; Jang, Moon-Sun; Gao, Guang Hui; Lee, Jung Hee; Lee, Doo Sung

2016-06-01

A novel type of pH-responsive biodegradable copolymer was developed based on methyloxy-poly(ethylene glycol)-block-poly[dopamine-2-(dibutylamino) ethylamine-l-glutamate] (mPEG-b-P(DPA-DE)LG) and applied to act as an intelligent nanocarrier system for magnetic resonance imaging (MRI). The mPEG-b-P(DPA-DE)LG copolymer was synthesized by a typical ring opening polymerization of N-carboxyanhydrides (NCAs-ROP) using mPEG-NH2 as a macroinitiator, and two types of amine-terminated dopamine groups and pH-sensitive ligands were grafted onto a side chain by a sequential aminolysis reaction. This design greatly benefits from the addition of the dopamine groups to facilitate self-assembly, as these groups can act as high-affinity anchors for iron oxide nanoparticles, thereby increasing long-term stability at physiological pH. The mPEG moiety in the copolymers helped the nanoparticles to remain well-dispersed in an aqueous solution, and pH-responsive groups could control the release of hydrophobic Fe3O4 nanoparticles in an acidic environment. The particle size of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles was measured by dynamic light scattering (DLS) and cryo-TEM. The superparamagnetic properties of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles were confirmed by a superconducting quantum interference device (SQUID). T2-weighted magnetic resonance imaging (MRI) of Fe3O4-loaded mPEG-b-P(DPA-DE)LG phantoms exhibited enhanced negative contrast with an r2 relaxivity of approximately 106.7 mM-1 s-1. To assess the ability of the Fe3O4-loaded mPEG-P(DE-DPA)LG micelles to act as MRI probes, we utilized a cerebral ischemia disease rat model with acidic tissue. We found that a gradual change in contrast in the cerebral ischemic area could be visualized by MRI after 1 h, and maximal signal loss was detected after 24 h post-injection. These results demonstrated that the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles can act as pH-triggered MRI probes for diagnostic imaging of acidic pathological tissues.A novel type of pH-responsive biodegradable copolymer was developed based on methyloxy-poly(ethylene glycol)-block-poly[dopamine-2-(dibutylamino) ethylamine-l-glutamate] (mPEG-b-P(DPA-DE)LG) and applied to act as an intelligent nanocarrier system for magnetic resonance imaging (MRI). The mPEG-b-P(DPA-DE)LG copolymer was synthesized by a typical ring opening polymerization of N-carboxyanhydrides (NCAs-ROP) using mPEG-NH2 as a macroinitiator, and two types of amine-terminated dopamine groups and pH-sensitive ligands were grafted onto a side chain by a sequential aminolysis reaction. This design greatly benefits from the addition of the dopamine groups to facilitate self-assembly, as these groups can act as high-affinity anchors for iron oxide nanoparticles, thereby increasing long-term stability at physiological pH. The mPEG moiety in the copolymers helped the nanoparticles to remain well-dispersed in an aqueous solution, and pH-responsive groups could control the release of hydrophobic Fe3O4 nanoparticles in an acidic environment. The particle size of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles was measured by dynamic light scattering (DLS) and cryo-TEM. The superparamagnetic properties of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles were confirmed by a superconducting quantum interference device (SQUID). T2-weighted magnetic resonance imaging (MRI) of Fe3O4-loaded mPEG-b-P(DPA-DE)LG phantoms exhibited enhanced negative contrast with an r2 relaxivity of approximately 106.7 mM-1 s-1. To assess the ability of the Fe3O4-loaded mPEG-P(DE-DPA)LG micelles to act as MRI probes, we utilized a cerebral ischemia disease rat model with acidic tissue. We found that a gradual change in contrast in the cerebral ischemic area could be visualized by MRI after 1 h, and maximal signal loss was detected after 24 h post-injection. These results demonstrated that the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles can act as pH-triggered MRI probes for diagnostic imaging of acidic pathological tissues. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06542a

Acid-Base Homeostasis

PubMed Central

Nakhoul, Nazih; Hering-Smith, Kathleen S.

2015-01-01

Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3− and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3− is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys. PMID:26597304

AMP-Activated Protein Kinase Interacts with the Peroxisome Proliferator-Activated Receptor Delta to Induce Genes Affecting Fatty Acid Oxidation in Human Macrophages.

PubMed

Kemmerer, Marina; Finkernagel, Florian; Cavalcante, Marcela Frota; Abdalla, Dulcineia Saes Parra; Müller, Rolf; Brüne, Bernhard; Namgaladze, Dmitry

2015-01-01

AMP-activated protein kinase (AMPK) maintains energy homeostasis by suppressing cellular ATP-consuming processes and activating catabolic, ATP-producing pathways such as fatty acid oxidation (FAO). The transcription factor peroxisome proliferator-activated receptor δ (PPARδ) also affects fatty acid metabolism, stimulating the expression of genes involved in FAO. To question the interplay of AMPK and PPARδ in human macrophages we transduced primary human macrophages with lentiviral particles encoding for the constitutively active AMPKα1 catalytic subunit, followed by microarray expression analysis after treatment with the PPARδ agonist GW501516. Microarray analysis showed that co-activation of AMPK and PPARδ increased expression of FAO genes, which were validated by quantitative PCR. Induction of these FAO-associated genes was also observed upon infecting macrophages with an adenovirus coding for AMPKγ1 regulatory subunit carrying an activating R70Q mutation. The pharmacological AMPK activator A-769662 increased expression of several FAO genes in a PPARδ- and AMPK-dependent manner. Although GW501516 significantly increased FAO and reduced the triglyceride amount in very low density lipoproteins (VLDL)-loaded foam cells, AMPK activation failed to potentiate this effect, suggesting that increased expression of fatty acid catabolic genes alone may be not sufficient to prevent macrophage lipid overload.

AMP-Activated Protein Kinase Interacts with the Peroxisome Proliferator-Activated Receptor Delta to Induce Genes Affecting Fatty Acid Oxidation in Human Macrophages

PubMed Central

Kemmerer, Marina; Finkernagel, Florian; Cavalcante, Marcela Frota; Abdalla, Dulcineia Saes Parra; Müller, Rolf; Brüne, Bernhard; Namgaladze, Dmitry

2015-01-01

AMP-activated protein kinase (AMPK) maintains energy homeostasis by suppressing cellular ATP-consuming processes and activating catabolic, ATP-producing pathways such as fatty acid oxidation (FAO). The transcription factor peroxisome proliferator-activated receptor δ (PPARδ) also affects fatty acid metabolism, stimulating the expression of genes involved in FAO. To question the interplay of AMPK and PPARδ in human macrophages we transduced primary human macrophages with lentiviral particles encoding for the constitutively active AMPKα1 catalytic subunit, followed by microarray expression analysis after treatment with the PPARδ agonist GW501516. Microarray analysis showed that co-activation of AMPK and PPARδ increased expression of FAO genes, which were validated by quantitative PCR. Induction of these FAO-associated genes was also observed upon infecting macrophages with an adenovirus coding for AMPKγ1 regulatory subunit carrying an activating R70Q mutation. The pharmacological AMPK activator A-769662 increased expression of several FAO genes in a PPARδ- and AMPK-dependent manner. Although GW501516 significantly increased FAO and reduced the triglyceride amount in very low density lipoproteins (VLDL)-loaded foam cells, AMPK activation failed to potentiate this effect, suggesting that increased expression of fatty acid catabolic genes alone may be not sufficient to prevent macrophage lipid overload. PMID:26098914

Adsorption of the compounds encountered in monosaccharide dehydration in zeolite beta.

PubMed

León, Marta; Swift, T Dallas; Nikolakis, Vladimiros; Vlachos, Dionisios G

2013-06-04

A comprehensive study of the adsorption of the compounds involved in the reaction of dehydration of fructose to 5-hydroxymethyl furfural (HMF) on the zeolite H-BEA with SiO2/Al2O3 = 18 has been carried out. Furthermore, a method for the estimation of the real adsorption loading from the experimentally measured excess adsorption is developed and applied to calculate the adsorption isotherms both in the case of single-solute and multisolute mixtures. It was found that zeolite H-BEA adsorbs HMF and levulinic acid from water mixtures to greater extent than sugars and formic acid, which prefer to partition in the aqueous phase. HMF and levulinic acid adsorption isotherms could be fitted in a Redlich-Peterson isotherm model, while the adsorption of formic acid is better fitted using the Freundlich model and sugars via the Henry model. Adsorption loadings decreased with increasing temperature (0, 25, and 40 °C), which is characteristic of an exothermic process. From the temperature dependence of the isotherms, the limiting heat of adsorption at zero coverage was determined using van't Hoff equation. Given the importance and the complexity of multicomponent systems, several experiments of adsorption of multisolute solutions have been carried out. In most of the cases, the ideal adsorbed solution theory (IAST) has been proven to satisfactorily predict adsorption from multisolute mixtures using as input the single-solute isotherms.

Light Absorption of Stratospheric Aerosols: Long-Term Trend and Contribution by Aircraft

NASA Technical Reports Server (NTRS)

Pueschel , R. F.; Gore, Waren J. Y. (Technical Monitor)

1997-01-01

Measurements of aerosol light-absorption coefficients are useful for studies of radiative transfer and heating rates. Ogren appears to have published the first light- absorption coefficients in the stratosphere in 1981, followed by Clarke in 1983 and Pueschel in 1992. Because most stratospheric soot appears to be due to aircraft operations, application of an aircraft soot aerosol emission index to projected fuel consumption suggests a threefold increase of soot loading and light absorption by 2025. Together, those four data sets indicate an increase in mid-visible light extinction at a rate of 6 % per year. This trend is similar to the increase per year of sulfuric acid aerosol and of commercial fleet size. The proportionality between stepped-up aircraft operations above the tropopause and increases in stratospheric soot and sulfuric acid aerosol implicate aircraft as a source of stratospheric pollution. Because the strongly light-absorbing soot and the predominantly light-scattering sulfuric acid aerosol increase at similar rates, however, the mid-visible stratospheric aerosol single scatter albedo is expected to remain constant and not approach a critical value of 0.98 at which stratospheric cooling could change to warming.

Effects of organic loading rate on hydrogen and volatile fatty acid production and microbial community during acidogenic hydrogenesis in a continuous stirred tank reactor using molasses wastewater.

PubMed

Yun, J; Cho, K-S

2016-12-01

Microbial community associated with hydrogen production and volatile fatty acids (VFAs) accumulation was characterized in acidogenic hydrogenesis using molasses wastewater as a feedstock. Hydrogen and VFAs production were measured under an organic loading rate (OLR) from 19 to 35 g-COD l -1  day -1 . The active microbial community was analysed using RNA-based massively parallel sequencing technique, and their correlation patterns were analysed using networking analysis. The continuous stirred tank reactor achieved stable hydrogen production at different OLR conditions, and the maximum hydrogen production rate (HPR) was 1·02 L-H 2  l -1  day -1 at 31·0 g-COD l -1  day -1 . Butyrate (50%) and acetate (38%) positively increased with increase in OLR. Total VFA production stayed around 7135 mg l -1 during the operation period. Although Clostridiales and Lactobacillales were relatively abundant, the HPR was positively associated with Pseudomonadaceae and Micrococcineae. Total VFA and acetate, butyrate and propionate concentrations were positively correlated with lactic acid bacteria (LAB) such as Bacillales, Sporolactobacillus and Lactobacillus. The close relationship between Pseudomonadaceae and Micrococcineae, and LAB play important roles for stable hydrogen and VFA production from molasses wastewater. Microbial information on hydrogen and VFA production can be useful to design and operate for acidogenic hydrogenesis using high strength molasses wastewater. © 2016 The Society for Applied Microbiology.

Pd-catalysts for DFAFC prepared by magnetron sputtering

NASA Astrophysics Data System (ADS)

Bieloshapka, I.; Jiricek, P.; Vorokhta, M.; Tomsik, E.; Rednyk, A.; Perekrestov, R.; Jurek, K.; Ukraintsev, E.; Hruska, K.; Romanyuk, O.; Lesiak, B.

2017-10-01

Samples of a palladium catalyst for direct formic acid fuel cell (DFAFC) applications were prepared on the Elat® carbon cloth by magnetron sputtering. The quantity of Pd was equal to 3.6, 120 and 720 μg/cm2. The samples were tested in a fuel cell for electro-oxidation of formic acid, and were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The XPS measurements revealed a high contribution of PdCx phase formed at the Pd/Elat® surface interface, with carbon concentration in PdCx from x = 9.9-14.6 at.%, resulting from the C substrate and CO residual gases. Oxygen groups, e.g. hydroxyl (-OH), carbonyl (Cdbnd O) and carboxyl (COOH), resulted from the synthesis conditions due to the presence of residual gases, electro-oxidation during the reaction and oxidation in the atmosphere. Because of the formation of CO and CO2 on the catalysts during the reaction, or because of poisoning by impurities containing the -CH3 group, together with the risk of Pd losses due to dissolution in formic acid, there was a negative effect of catalyst degradation on the active area surface. The effect of different loadings of Pd layers led to increasing catalyst efficiency. Current-voltage curves showed that different amounts of catalyst did not increase the DFAFC power to a great extent. One reason for this was the catalyst structure formed on the carbon cloth. AFM and SEM measurements showed a layer-by-layer growth with no significant variations in morphology. The results for electric power recalculated for the Pd loading per 1 mg of catalyst layers in comparison to carbon substrates decorated by Pd nanoparticles showed that there is potential for applying anodes for formic acid fuel cells prepared by magnetron sputtering.

Myocardial reloading after extracorporeal membrane oxygenation alters substrate metabolism while promoting protein synthesis.

PubMed

Kajimoto, Masaki; O'Kelly Priddy, Colleen M; Ledee, Dolena R; Xu, Chun; Isern, Nancy; Olson, Aaron K; Des Rosiers, Christine; Portman, Michael A

2013-08-19

Extracorporeal membrane oxygenation (ECMO) unloads the heart, providing a bridge to recovery in children after myocardial stunning. ECMO also induces stress which can adversely affect the ability to reload or wean the heart from the circuit. Metabolic impairments induced by altered loading and/or stress conditions may impact weaning. However, cardiac substrate and amino acid requirements upon weaning are unknown. We assessed the hypothesis that ventricular reloading with ECMO modulates both substrate entry into the citric acid cycle (CAC) and myocardial protein synthesis. Sixteen immature piglets (7.8 to 15.6 kg) were separated into 2 groups based on ventricular loading status: 8-hour ECMO (UNLOAD) and postwean from ECMO (RELOAD). We infused into the coronary artery [2-(13)C]-pyruvate as an oxidative substrate and [(13)C6]-L-leucine as an indicator for amino acid oxidation and protein synthesis. Upon RELOAD, each functional parameter, which were decreased substantially by ECMO, recovered to near-baseline level with the exclusion of minimum dP/dt. Accordingly, myocardial oxygen consumption was also increased, indicating that overall mitochondrial metabolism was reestablished. At the metabolic level, when compared to UNLOAD, RELOAD altered the contribution of various substrates/pathways to tissue pyruvate formation, favoring exogenous pyruvate versus glycolysis, and acetyl-CoA formation, shifting away from pyruvate decarboxylation to endogenous substrate, presumably fatty acids. Furthermore, there was also a significant increase of tissue concentrations for all CAC intermediates (≈80%), suggesting enhanced anaplerosis, and of fractional protein synthesis rates (>70%). RELOAD alters both cytosolic and mitochondrial energy substrate metabolism, while favoring leucine incorporation into protein synthesis rather than oxidation in the CAC. Improved understanding of factors governing these metabolic perturbations may serve as a basis for interventions and thereby improve success rate from weaning from ECMO.

Preparation and characterization of pH sensitive crosslinked Linseed polysaccharides-co-acrylic acid/methacrylic acid hydrogels for controlled delivery of ketoprofen.

PubMed

Shabir, Farya; Erum, Alia; Tulain, Ume Ruqia; Hussain, Muhammad Ajaz; Ahmad, Mahmood; Akhter, Faiza

2017-01-01

Some pH responsive polymeric matrix of Linseed ( Linum usitatissimum ), L. hydrogel (LSH) was prepared by free radical polymerization using potassium persulfate (KPS) as an initiator, N,N -methylene bisacrylamide (MBA) as a crosslinker, acrylic acid (AA) and methacrylic acid (MAA) as monomers; while ketoprofen was used as a model drug. Different formulations of LSH-co-AA and LSH-co-MAA were formulated by varying the concentration of crosslinker and monomers. Structures obtained were thoroughly characterized using Fourier transforms infrared (FTIR) spectroscopy, XRD analysis and Scanning electron microscopy. Sol-gel fractions, porosity of the materials and ketoprofen loading capacity were also measured. Swelling and in vitro drug release studies were conducted at simulated gastric fluids, i.e., pH 1.2 and 7.4. FTIR evaluation confirmed successful grafting of AA and MAA to LSH backbone. XRD studies showed retention of crystalline structure of ketoprofen in LSH-co-AA and its amorphous dispersion in LSH-co-MAA. Gel content was increased by increasing MBA and monomer content; whereas porosity of hydrogel was increased by increasing monomer concentration and decreased by increasing MBA content. Swelling of copolymer hydrogels was high at pH 7.4 and low at pH 1.2. Ketoprofen release showed an increasing trend by increasing monomer content; however it was decreased with increasing MBA content. Sustained release of ketoprofen was noted from copolymers and release followed Korsmeyer-Peppas model.

Arginine, glycine, aspartic acid peptide-modified paclitaxel and curcumin co-loaded liposome for the treatment of lung cancer: in vitro/vivo evaluation.

PubMed

Jiang, Kanqiu; Shen, Mingjing; Xu, Weihua

2018-01-01

In this study, a novel arginine, glycine, aspartic acid peptide (RGD)-modified paclitaxel and curcumin co-loaded liposomes were developed to evaluate their antitumor activity in vitro and in vivo. Co-loaded liposomes were prepared using the solvent evaporation method. The particles had spherical shapes under electron microscopy with sizes <130 nm. By comparison with the free drug, RGD-modified paclitaxel and curcumin co-loaded liposomes and paclitaxel and curcumin co-loaded liposomes have sustained-release properties in vitro. In vivo, there was no significant difference in pharmacokinetic parameters between the RGD-modified paclitaxel and curcumin co-loaded liposomes and paclitaxel and curcumin co-loaded liposomes. A strong green fluorescence was observed in the cytoplasmic region after incubation of RGD-modified paclitaxel and curcumin co-loaded liposomes for 2 h. RGD-modified paclitaxel and curcumin co-loaded liposomes showed a superior antiproliferative effect on A549 cells with a possible mechanism that suppressed the multidrug resistance phenomenon and exhibited a clear synergistic effect. The results indicate that RGD-modified paclitaxel and curcumin co-loaded liposomes had a better antitumor effect in vivo than the non-modified LPs. These results indicate that RGD-modified co-loaded liposomes are a promising candidate for antitumor drug delivery.

Urine chemistry

MedlinePlus

... rate 24-hour urine protein Acid loading test (pH) Adrenalin - urine test Amylase - urine Bilirubin - urine Calcium - urine Citric acid ... Urine dermatan sulfate Urine - hemoglobin Urine metanephrine Urine pH Urine specific gravity Vanillylmandelic acid (VMA)

Treatment of phenolic wastewater in an anaerobic fixed bed reactor (AFBR) - recovery after shock loading.

PubMed

Bajaj, Mini; Gallert, Claudia; Winter, Josef

2009-03-15

An anaerobic fixed bed reactor (AFBR) was run for 550 days with a mixed microbial flora to stabilize synthetic wastewater that contained glucose and phenol as main carbon sources. The influent phenol concentration was gradually increased from 2 to 40 mmol/l within 221 days. The microbial flora was able to adapt to this high phenol concentration with an average of 94% phenol removal. Microbial adaptation at such a high phenol concentration is not reported elsewhere. The maximum phenol removal observed before the phenol shock load was 39.47 mmol/l or 3.7 g phenol/l at a hydraulic retention time (HRT) of 2.5 days and an organic loading rate (OLR) of 5.3 g/l.d which amounts to a phenol removal rate of ca. 15.8 mmol phenol/l.d. The chemical oxygen demand (COD) removal before exposing the reactor to a shock load corresponded with phenol removal. A shock load was induced in the reactor by increasing the phenol concentration from 40 to 50 mmol/l in the influent. The maximum phenol removal rate observed after shock load was 18 mmol/l.d at 5.7 g COD/l.d. But this was not a stable rate and a consistent drop in COD and phenol removal was observed for 1 week, followed by a sharp decline and production of fatty acids. Recovery of the reactor was possible only when no feed was provided to the reactor for 1 month and the phenol concentration was increased gradually. When glucose was omitted from the influent, unknown intermediates of anaerobic phenol metabolism were observed for some time.

Catalytic performance of V2O5-MoO3/γ-Al2O3 catalysts for partial oxidation of n-hexane1

NASA Astrophysics Data System (ADS)

Mahmoudian, R.; Khodadadi, Z.; Mahdavi, Vahid; Salehi, Mohammed

2016-01-01

In the current study, a series of V2O5-MoO3 catalyst supported on γ-Al2O3 with various V2O5 and MoO3 loadings was prepared by wet impregnation technique. The characterization of prepared catalysts includes BET surface area, powder X-ray diffraction (XRD), and oxygen chemisorptions. The partial oxidation of n-hexane by air over V2O5-MoO3/γ-Al2O3 catalysts was carried out under flow condition in a fixed bed glass reactor. The effect of V2O5 loading, temperature, MoO3 loading, and n-hexane LHSV on the n-hexane conversion and the product selectivity were investigated. The partial oxygenated products of n-hexane oxidation were ethanol, acetic anhydride, acetic acid, and acetaldehyde. The 10% V2O5-1%MoO3/γ-Al2O3 was found in most active and selective catalyst during partial oxidation of n-hexane. The results indicated that by increasing the temperature, the n-hexane conversion increases as well, although the selectivity of the products passes through a maximum by increasing the temperature.

Biodistribution of indocyanine green-loaded nanoparticles with surface modifications of PEG and folic acid.

PubMed

Ma, Ying; Sadoqi, Mostafa; Shao, Jun

2012-10-15

To establish the biodistribution profile of the PLGA nanoparticles with dual surface modifications of PEG and folic acid (FA) in mice xenografted with MDA-MB-231 human breast cancer cells with high expression of folate receptor (FR); and to illustrate that the modified nanoparticles can target the loaded indocyanine green (ICG) to the tumor with high FR expression. ICG-loaded nanoparticles were prepared with PLGA (non-modified nanoparticles, NM-NP) or mPEG-PLGA and FA-PLGA (dual modified nanoparticles, DM-NP). Biodistribution of the ICG-loaded nanoparticles (1.25 mg/kg) after i.v. injection was investigated on athymic mice transplanted with MDA-MB-231 tumor. ICG concentration in plasma from the DM-NP group was significantly (p<0.05) higher than the NM-NP group from 90 min to the end of the study (12 h). After 4 h, the drug concentration in the tumor tissue from the DM-NP started to be significantly (p<0.05) higher than the NM-NP until 12 h. Compared to the NM-NP, the DM-NP increased the AUC(0-12 h) in plasma by 245% and the AUC(0-12 h) in tumor by 194%, while decreased the AUC(0-12 h) in liver by 13%. The accumulation of DM-NP into the tumor was significantly higher than NM-NP due to the long circulation and FR-mediated uptake. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization and oxidative stability of purslane seed oil microencapsulated in yeast cells biocapsules.

PubMed

Kavosi, Maryam; Mohammadi, Abdorreza; Shojaee-Aliabadi, Saeedeh; Khaksar, Ramin; Hosseini, Seyede Marzieh

2018-05-01

Purslane seed oil, as a potential nutritious source of omega-3 fatty acid, is susceptible to oxidation. Encapsulation in yeast cells is a possible approach for overcoming this problem. In the present study, purslane seed oil was encapsulated in non-plasmolysed, plasmolysed and plasmolysed carboxy methyl cellulose (CMC)-coated Saccharomyces cerevisiae cells and measurements of oil loading capacity (LC), encapsulation efficiency (EE), oxidative stability and the fatty acid composition of oil-loaded microcapsules were made. Furthermore, investigations of morphology and thermal behavior, as well as a Fourier transform-infrared (FTIR) analyses of microcapsules, were performed. The values of EE, LC were approximately 53-65% and 187-231 g kg -1 , respectively. Studies found that the plasmolysis treatment increased EE and LC and decreased the mean peroxide value (PV) of microencapsulated oil. The presence of purslane seed oil in yeast microcapsules was confirmed by FTIR spectroscopy and differential scanning calorimetry analyses. The lowest rate of oxidation belonged to the oil-loaded plasmolysed CMC-coated microcapsules (16.73 meqvO 2 kg -1 ), whereas the highest amount of oxidation regardless of native oil referred to the oil-loaded in non-plasmolysed cells (28.15 meqvO 2 kg -1 ). The encapsulation of purslane seed oil in the yeast cells of S. cerevisiae can be considered as an efficient approach for extending the oxidative stability of this nutritious oil and facilitating its application in food products. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Abnormal distal renal tubular acidification in patients with low bone mass: prevalence and impact of alkali treatment.

PubMed

Sromicki, Jerzy Jan; Hess, Bernhard

2017-06-01

Chronic acid retention is known to promote bone dissolution. In this study, 23 % of patients with osteopenia/osteoporosis were diagnosed with abnormal distal renal tubular acidification (dRTA), a kidney dysfunction leading to chronic acid retention. Treating those patients with alkali-therapy shows improvement in bone density. To evaluate the prevalence of abnormal distal renal tubular acidification in patients with low bone mass (LBM) and the impact of additional alkali treatment on bone density in patients with concomitant LBM and dRTA,183 patients referred for metabolic evaluation of densitometrically proven low bone mass were screened for abnormal distal renal tubular acidification between 2006 and 2013. In all LBM urine pH (U-pH) was measured in the 2nd morning urines after 12 h of fasting. If U-pH was ≥5.80, LBM underwent a 1-day ammonium chloride loading, and U-pH was remeasured the next morning. If U-pH after acid loading did not drop below 5.45, patients were diagnosed with abnormal distal renal tubular acidification. Normal values were obtained from 21 healthy controls. All LBM with dRTA were recommended alkali citrate in addition to conventional therapy of LBM, and follow-up DXAs were obtained until 2014. 85 LBM underwent NH 4 Cl loading. 42 LBM patients were diagnosed with incomplete dRTA (idRTA; prevalence 23.0 %). During follow-up (1.6-8 years) of idRTA-LBM patients, subjects adhering to alkali treatment tended to improve BMD at all sites measured, whereas BMD of non-adherent idRTA patients worsened/remained unchanged. (1) About one out of four patients with osteopenia/osteoporosis has idRTA. (2) Upon NH 4 Cl loading, idRTA patients do not lower urine pH normally, but show signs of increased acid-buffering by bone dissolution. (3) In idRTA patients with low bone mass on conventional therapy, additional long-term alkali treatment improves bone mass at lumbar spine and potentially at other bone sites. (4) All patients with low bone mass undergoing metabolic evaluation should be screened for idRTA.

Differential Effects of Dietary Fat Content and Protein Source on Bone Phenotype and Fatty Acid Oxidation in Female C57Bl/6 Mice

PubMed Central

Sawin, Emily A.; Stroup, Bridget M.; Murali, Sangita G.; O’Neill, Lucas M.; Ntambi, James M.

2016-01-01

Background Glycomacropeptide (GMP) is a 64-amino acid glycophosphopeptide released from κ-casein during cheesemaking that promotes satiety, reduces body fat, increases bone mass and infers prebiotic and anti-inflammatory effects. The impact of adiposity and gender on bone health is unclear. Objective To determine how feeding female mice diets providing 60% Fat Kcal (high-fat) or 13% Fat Kcal (control) with either GMP or casein as the protein source impacts: body composition, ex vivo fatty acid oxidation, bone (femoral) biomechanical performance, and the relationship between body composition and bone. Methods Weanling female C57Bl/6 mice were fed high-fat (60% Fat Kcal) or control diets (13% Fat Kcal) with GMP or casein from 3 to 32 weeks of age with assessment of body weight and food intake. Body composition was assessed by dual-energy X-ray absorptiometry (DXA). Fatty acid oxidation was measured in liver, muscle, and fat tissues using 14C-palmitate. Plasma concentrations of hormones and cytokines were determined. Bone biomechanical performance was assessed by the 3-point bending test. Results Female mice fed high-fat diets showed increased fatty acid oxidation capacity in both gastrocnemius muscle and brown adipose tissue compared to mice fed the control diets with a lower fat content. Despite increased fat mass in mice fed the high-fat diets, there was little evidence of glucose impairment or inflammation. Mice fed the high-fat diets had significantly greater total body bone mineral density (BMD), femoral BMD, and femoral cross-sectional area than mice fed the control diets. Femora of mice fed the high-fat diets had increased yield load and maximum load before fracture, consistent with greater bone strength, but reduced post-yield displacement or ductility, consistent with bone brittleness. Female mice fed a high-fat GMP diet displayed increased fat oxidation capacity in subcutaneous fat relative to mice fed the high-fat casein diet. Regardless of dietary fat content, GMP increased total body bone mineral content and femur length. The prebiotic properties of GMP may mediate the beneficial effects of GMP on bone. Conclusions Female mice adapt to high-fat feeding by increasing oxidative capacity in muscle tissue and to a lesser extent brown adipose tissue. High-fat feeding in female mice leads to development of a bone phenotype where femora show increased BMD and are stronger, yet more brittle. The increased brittleness of bone was associated with increased body fat content due to high-fat feeding. In summary, high-fat feeding in female mice increases mineralization of bone, but negatively impacts bone quality resulting in brittle bones. PMID:27695036

Light-Responsive and pH-Responsive DNA Microcapsules for Controlled Release of Loads.

PubMed

Huang, Fujian; Liao, Wei-Ching; Sohn, Yang Sung; Nechushtai, Rachel; Lu, Chun-Hua; Willner, Itamar

2016-07-20

A method to assemble light-responsive or pH-responsive microcapsules loaded with different loads (tetramethylrhodamine-modified dextran, TMR-D; microperoxidase-11, MP-11; CdSe/ZnS quantum dots; or doxorubicin-modified dextran, DOX-D) is described. The method is based on the layer-by-layer deposition of sequence-specific nucleic acids on poly(allylamine hydrochloride)-functionalized CaCO3 core microparticles, loaded with the different loads, that after the dissolution of the core particles with EDTA yields the stimuli-responsive microcapsules that include the respective loads. The light-responsive microcapsules are composed of photocleavable o-nitrobenzyl-phosphate-modified DNA shells, and the pH-responsive microcapsules are made of a cytosine-rich layer cross-linked by nucleic acid bridges. Irradiating the o-nitrobenzyl phosphate-functionalized microcapsules, λ = 365 nm, or subjecting the pH-responsive microcapsules to pH = 5.0, results in the cleavage of the microcapsule shells and the release of the loads. Preliminary studies address the cytotoxicity of the DOX-D-loaded microcapsules toward MDA-MB-231 breast cancer cells and normal MCF-10A breast epithelial cells. Selective cytotoxicity of the DOX-D-loaded microcapsules toward cancer cells is demonstrated.

Graphene and water-based elastomers thin-film composites by dip-moulding.

PubMed

Iliut, Maria; Silva, Claudio; Herrick, Scott; McGlothlin, Mark; Vijayaraghavan, Aravind

2016-09-01

Thin-film elastomers (elastic polymers) have a number of technologically significant applications ranging from sportswear to medical devices. In this work, we demonstrate that graphene can be used to reinforce 20 micron thin elastomer films, resulting in over 50% increase in elastic modulus at a very low loading of 0.1 wt%, while also increasing the elongation to failure. This loading is below the percolation threshold for electrical conductivity. We demonstrate composites with both graphene oxide and reduced graphene oxide, the reduction being undertaken in-situ or ex-situ using a biocompatible reducing agent in ascorbic acid. The ultrathin films were cast by dip moulding. The transparency of the elastomer films allows us to use optical microscopy image and confirm the uniform distribution as well as the conformation of the graphene flakes within the composite.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuperman, R.G.

Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggestmore » that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.« less

Inhibiting excessive acidification using zero-valent iron in anaerobic digestion of food waste at high organic load rates.

PubMed

Kong, Xin; Wei, Yonghong; Xu, Shuang; Liu, Jianguo; Li, Huan; Liu, Yili; Yu, Shuyao

2016-07-01

Excessive acidification occurs frequently in food waste (FW) anaerobic digestion (AD) due to the high carbon-to-nitrogen ratio of FW. In this study, zero-valent iron (ZVI) was applied to prevent the excessive acidification. All of the control groups, without ZVI addition (pH∼5.3), produced little methane (CH4) and had high volatile fatty acids/bicarbonate alkalinity (VFA/ALK). By contrast, at OLR of 42.32gVS/Lreactor, the pH of effluent from the reactors with 0.4g/gVSFWadded of ZVI increased to 7.8-8.2, VFA/ALK decreased to <0.1, and the final CH4 yield was ∼380mL/gVSFWadded, suggesting inhibition of excessive acidification. After adding powdered or scrap metal ZVI to the acidogenic reactors, the fractional content of butyric acid changed from 30-40% to 0%, while, that of acetic acid increased. These results indicate that adding ZVI to FW digestion at high OLRs could eliminate excessive acidification by promoting butyric acid conversion and enhancing methanogen activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Abandoned mine drainage in the Swatara Creek Basin, southern anthracite coalfield, Pennsylvania, USA: 2. performance of treatment systems

USGS Publications Warehouse

Cravotta, Charles A.

2010-01-01

A variety of passive and semi-passive treatment systems were constructed by state and local agencies to neutralize acidic mine drainage (AMD) and reduce the transport of dissolved metals in the upper Swatara Creek Basin in the Southern Anthracite Coalfield in eastern Pennsylvania. To evaluate the effectiveness of selected treatment systems installed during 1995–2001, the US Geological Survey collected water-quality data at upstream and downstream locations relative to each system eight or more times annually for a minimum of 3 years at each site during 1996–2007. Performance was normalized among treatment types by dividing the acid load removed by the size of the treatment system. For the limestone sand, open limestone channel, oxic limestone drain, anoxic limestone drain (ALD), and limestone diversion well treatment systems, the size was indicated by the total mass of limestone; for the aerobic wetland systems, the size was indicated by the total surface area of ponds and wetlands. Additionally, the approximate cost per tonne of acid treated over an assumed service life of 20 years was computed. On the basis of these performance metrics, the limestone sand, ALD, oxic limestone drain, and limestone diversion wells had similar ranges of acid-removal efficiency and cost efficiency. However, the open limestone channel had lower removal efficiency and higher cost per ton of acid treated. The wetlands effectively attenuated metals transport but were relatively expensive considering metrics that evaluated acid removal and cost efficiency. Although the water-quality data indicated that all treatments reduced the acidity load from AMD, the ALD was most effective at producing near-neutral pH and attenuating acidity and dissolved metals. The diversion wells were effective at removing acidity and increasing pH of downstream water and exhibited unique potential to treat moderate to high flows associated with storm flow conditions.

[Degradation of styrene by coupling ultraviolet and biofiltration].

PubMed

Sha, Hao-Lei; Yang, Guo-Jing; Xia, Jing-Fen

2013-12-01

Purification of styrene by ultraviolet (UV)-biofiltration was studied in this paper. The light source and the biofilm carrier were ozone producing lamp at 185 nm and the peat, palm fiber, porous acticarbon, respectively. Styrene inlet concentration was controlled between 320-583 mg x m(-3), and the removal efficiency remained above 95% after stabilization. The UV converted styrene into more soluble and biodegradable intermediates, such as alcohol, aldehyde and acid, thus the performance of biofilter can be improved. In the stable operation stage, the variation of inlet concentration did not affect the removal efficiency when the total residence time (TRT) was long, however, the inlet concentration obviously affected the removal efficiency when the TRT decreased. The removal load of coupling system increased linearly with increasing inlet load, and the removal efficiency was higher than 95% under a TRT of 102 s. When TRT was 68 s and the inlet load was low, the variation of removal load complied with the law described above, but it gradually deviated from the straight line and tended to stabilized at a certain value when the inlet load became higher than 30 g x (m3 x h)(-). If considering the fluctuation of styrene concentration only, the contribution rate of ultraviolet photolysis to styrene removal was greater than that of the biofilter, and the removal effect could be restored on the fourth day, after closing the system for ten days and restarting.

Induction of Th1 polarized immune responses by thiolated Eudragit-coated F4 and F18 fimbriae of enterotoxigenic Escherichia coli.

PubMed

Lee, Won-Jung; Cha, Seungbin; Shin, Minkyoung; Islam, Mohammad Ariful; Cho, Chong-su; Yoo, Han Sang

2011-10-01

Diarrhea in newborn and weaned piglets is mainly induced by enterotoxigenic Escherichia coli (ETEC) with fimbriae F4 (K88) and F18 (F107). In this study, we evaluated F4 and F18 coated with thiolated Eudragit microspheres (TEMS) as a candidate for an oral vaccine. The average particle sizes of TEMS, F4-loaded TEMS, and F18-loaded TEMS were measured as 4.2±0.75 μm, 4.7±0.50 μm, and 4.5±0.37 μm, respectively. F4 is more efficiently encapsulated than F18 in the loading with TEMS. In the release test, F4 and F18 fimbriae were protected in acidic circumstances, whereas most were released at pH 7.4 of intestine circumstances. Production of TNF-α and NO from RAW 264.7 cells was increased in a time-dependent manner after exposure to all groups, whereas only F4- or F18-loaded TEMS-stimulated IL-6 secretion. The levels of IFN-γ from mouse splenocytes after exposure to F4 or F18 were increased while IL-4 was not detectable. These results suggest that F4- and F18-loaded TEMS may effectively induce immune response with the efficient release of antigens to appropriate target sites. Copyright © 2011 Elsevier B.V. All rights reserved.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

PubMed Central

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N′-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor. PMID:26316749

Ozone and hydrogen peroxide as strategies to control biomass in a trickling filter to treat methanol and hydrogen sulfide under acidic conditions.

PubMed

García-Pérez, Teresa; Le Borgne, Sylvie; Revah, Sergio

2016-12-01

The operation and performance of a biotrickling filter for methanol (MeOH) and hydrogen sulfide (H 2 S) removal at acid pH was studied. Excess biomass in the filter bed, causing performance loss and high pressure drop, was controlled by intermittent addition, of ozone (O 3 ) and hydrogen peroxide (H 2 O 2 ). The results showed that after adaptation to acid pH, the maximum elimination capacity (EC) reached for MeOH was 565 g m -3  h -1 (97 % RE). High MeOH loads resulted in increased biomass concentration within the support, triggering reductions in the removal efficiency (RE) for both compounds close to 50 %, and high pressure drop. At this stage, an inlet load of 150.2 ± 16.7 g m -3  h -1 of O 3 was fed by 38 days favoring biomass detachment, and EC recovery and lower pressure dropped with a maximum elimination capacity of 587 g m -3  h -1 (81 % RE) and 15.8 g m -3  h -1 (97 % RE) for MeOH and H 2 S, respectively. After O 3 addition, a rapid increase in biomass content and higher fluctuations in pressure drop were observed reducing the system performance. A second treatment with oxidants was implemented feeding a O 3 load of 4.8 ± 0.1 g m -3  h -1 for 7 days, followed by H 2 O 2 addition for 23 days, registering 607.5 g biomass  L -1 packing before and 367.5 g biomass  L -1 packing after the oxidant addition. PCR-DGGE analysis of different operating stages showed a clear change in the bacterial populations when O 3 was present while the fungal population was less affected.

[Development of biphasic drug-loading lipid emulsion of Salvia miltiorrhiza and its quality evaluation].

PubMed

Wang, Yin-Yan; Li, Xi; Lai, Xiu-Jun; Li, Wei; Yang, Ya-Jing; Chu, Ting; Mao, Sheng-Jun

2014-10-01

The feasibility of simultaneously loading both liposoluble and water-soluble components of Salvia miltiorrhiza in emulsion was discussed, in order to provide new ideas in comprehensive application of effective components in S. miltiorrhiza in terms of technology of pharmaceutics. With tanshinone II (A) and salvianolic acid B as raw materials, soybean phospholipid and poloxamer 188 as emulsifiers, and glycerin as isoosmotic regulator, the central composite design-response surface method was employed to optimize the prescription. The coarse emulsion was prepared with the high-speed shearing method and then homogenized in the high pressure homogenizer. The biphasic drug-loading intravenous emulsion was prepared to investigate its pharmaceutical properties and stability. The prepared emulsion is orange-yellow, with the average diameter of 241 nm and Zeta potential of -35.3 mV. Specifically, the drug loading capacity of tanshinone II (A) and salvianolic acid B were 0.5 g x L(-1) and 1 g x L(-1), respectively, with a good stability among long-term retention samples. According to the results, the prepared emulsion could load liposoluble tanshinone II (A) and water-soluble salvianolic acid B simultaneously, which lays a pharmaceutical foundation for giving full play to the efficacy of S. miltiorrhiza.

Block Copolymer Micelles as Nanocontainers for Controlled Release of Proteins from Biocompatible Oil Phases

PubMed Central

2009-01-01

Biocompatible oils are used in a variety of medical applications ranging from vaccine adjuvants to vehicles for oral drug delivery. To enable such nonpolar organic phases to serve as reservoirs for delivery of hydrophilic compounds, we explored the ability of block copolymer micelles in organic solvents to sequester proteins for sustained release across an oil−water interface. Self-assembly of the block copolymer, poly(ϵ-caprolactone)-block-poly(2-vinyl pyridine) (PCL-b-P2VP), was investigated in toluene and oleic acid, a biocompatible naturally occurring fatty acid. Micelle formation in toluene was characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) imaging of micelles cast onto silicon substrates. Cryogenic transmission electron microscopy confirmed a spherical morphology in oleic acid. Studies of homopolymer solubility implied that micelles in oleic acid consist of a P2VP corona and a PCL core, while P2VP formed the core of micelles assembled in toluene. The loading of two model proteins (ovalbumin (ova) and bovine serum albumin (BSA)) into micelles was demonstrated with loadings as high as 7.8% wt of protein per wt of P2VP in oleic acid. Characterization of block copolymer morphology in the two solvents after protein loading revealed spherical particles with similar size distributions to the as-assembled micelles. Release of ova from micelles in oleic acid was sustained for 12−30 h upon placing the oil phase in contact with an aqueous bath. Unique to the situation of micelle assembly in an oily phase, the data suggest protein is sequestered in the P2VP corona block of PCL-b-P2VP micelles in oleic acid. More conventionally, protein loading occurs in the P2VP core of micelles assembled in toluene. PMID:19235932

Comparative evaluation of acid and alkaline sulfite pretreatments for enzymatic saccharification of bagasses from three different sugarcane hybrids.

PubMed

Monte, Joseana R; Laurito-Friend, Debora F; Ferraz, André; Milagres, Adriane M F

2018-04-26

Sugarcane bagasses from three experimental sugarcane hybrids and a mill-reference sample were used to compare the efficiency and mode of action of acid and alkaline sulfite pretreatment processes. Varied chemical loads and reaction temperatures were used to prepare samples with distinguished characteristics regarding xylan and lignin removals, as well as sulfonation levels of residual lignins. The pretreatment with low sulfite loads (5%) under acidic conditions (pH 2) provided maximum glucose yield of 70% during enzymatic hydrolysis with cellulases (10 FPU/g) and β-glucosidases (20 UI/g bagasse). In this case, glucan enzymatic conversion from pretreated materials was mostly associated with extensive xylan removal (70-100%) and partial delignification occurred during the pretreatment. The use of low sulfite loads under acidic conditions required pretreatment temperatures of 160°C. In contrast, at a lower pretreatment temperature (120°C), alkaline sulfite process achieved similar glucan digestibility, but required a higher sulfite load (7.5%). Residual xylans from acid pretreated materials were almost completely hydrolysed by commercial enzymes, contrasting with relatively lower xylan to xylose conversions observed in alkaline pretreated samples. Efficient xylan removal during acid sulfite pretreatment and also during enzymatic digestion can be useful to enhance glucan accessibility and digestibility by cellulases. Alkaline sulfite process also provided substrates with high glucan digestibility, mainly associated with delignification and sulfonation of residual lignins. The results demonstrate that temperature, pH and sulfite can be combined for reducing lignocellulose recalcitrance and achieve similar glucan conversion rates in the alkaline and acid sulfite pretreated bagasses. This article is protected by copyright. All rights reserved. © 2018 American Institute of Chemical Engineers.

Urine pH is an indicator of dietary acid-base load, fruit and vegetables and meat intakes: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population study.

PubMed

Welch, Ailsa A; Mulligan, Angela; Bingham, Sheila A; Khaw, Kay-Tee

2008-06-01

Evidence exists that a more acidic diet is detrimental to bone health. Although more precise methods exist for measurement of acid-base balance, urine pH reflects acid-base balance and is readily measurable but has not been related to habitual dietary intake in general populations. The present study investigated the relationship between urine pH and dietary acid-base load (potential renal acid load; PRAL) and its contributory food groups (fruit and vegetables, meats, cereal and dairy foods). There were 22,034 men and women aged 39-78 years living in Norfolk (UK) with casual urine samples and dietary intakes from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk FFQ. A sub-study (n 363) compared pH in casual samples and 24 h urine and intakes from a 7 d diary and the FFQ. A more alkaline diet (low PRAL), high fruit and vegetable intake and lower consumption of meat was significantly associated with a more alkaline urine pH before and after adjustment for age, BMI, physical activity and smoking habit and also after excluding for urinary protein, glucose, ketones, diagnosed high blood pressure and diuretic medication. In the sub-study the strongest relationship was found between the 24 h urine and the 7 d diary. In conclusion, a more alkaline diet, higher fruit and vegetable and lower meat intake were related to more alkaline urine with a magnitude similar to intervention studies. As urine pH relates to dietary acid-base load its use to monitor change in consumption of fruit and vegetables, in individuals, warrants further investigation.

One-step pretreatment of yellow poplar biomass using peracetic acid to enhance enzymatic digestibility.

PubMed

Lee, Hyeong Rae; Kazlauskas, Romas J; Park, Tai Hyun

2017-09-22

Pretreatment of biomass with dilute acid requires high temperatures of >160 °C to remove xylan and does not remove lignin. Here we report that the addition of peracetic acid, a strong oxidant, to mild dilute acid pretreatment reduces the temperature requirement to only 120 °C. Pretreatment of yellow poplar with peracetic acid (300 mM, 2.3 wt%) and dilute sulfuric acid (100 mM, 1.0 wt%) at 120 °C for 5 min removed 85.7% of the xylan and 90.4% of the lignin leaving a solid consisting of 75.6% glucan, 6.0% xylan and 4.7% lignin. Low enzyme loadings of 5 FPU/g glucan and 10 pNPGU/g glucan converted this solid to glucose with an 84.0% yield. This amount of glucose was 2.5 times higher than with dilute acid-pretreated solid and 13.8 times higher than with untreated yellow poplar. Thus, the addition of peracetic acid, easily generated from acetic acid and hydrogen peroxide, dramatically increases the effectiveness of dilute acid pretreatment of biomass.

Site-specific critical acid load estimates for forest soils in the Osborn Creek watershed, Michigan

Treesearch

Trevor Hobbs; Jason Lynch; Randy Kolka

2017-01-01

Anthropogenic acid deposition has the potential to accelerate leaching of soil cations, and in turn, deplete nutrients essential to forest vegetation. The critical load concept, employing a simple mass balance (SMB) approach, is often used to model this process. In an evaluation under the U.S. Forest Service Watershed Condition Framework program, soils in all 6th level...

Polyacrylic acid@zeolitic imidazolate framework-8 nanoparticles with ultrahigh drug loading capability for pH-sensitive drug release.

PubMed

Ren, Hong; Zhang, Lingyu; An, Jiping; Wang, Tingting; Li, Lu; Si, Xiaoyan; He, Liu; Wu, Xiaotong; Wang, Chungang; Su, Zhongmin

2014-01-28

The polyacrylic acid@zeolitic imidazolate framework-8 (PAA@ZIF-8) nanoparticles (NPs) were first fabricated using a facile and simple route. It is worthwhile noting that the as-fabricated PAA@ZIF-8 NPs possessed ultrahigh doxorubicin (DOX) loading capability (1.9 g DOX g(-1) NPs), which were employed as pH-dependent drug delivery vehicles.

Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity

Treesearch

Harbin Li; Steven G. McNulty

2007-01-01

Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL...

Acid rock drainage and climate change

USGS Publications Warehouse

Nordstrom, D. Kirk

2009-01-01

Rainfall events cause both increases and decreases in acid and metals concentrations and their loadings from mine wastes, and unmined mineralized areas, into receiving streams based on data from 3 mines sites in the United States and other sites outside the US. Gradual increases in concentrations occur during long dry spells and sudden large increases are observed during the rising limb of the discharge following dry spells (first flush). By the time the discharge peak has occurred, concentrations are usually decreased, often to levels below those of pre-storm conditions and then they slowly rise again during the next dry spell. These dynamic changes in concentrations and loadings are related to the dissolution of soluble salts and the flushing out of waters that were concentrated by evaporation. The underlying processes, pyrite oxidation and host rock dissolution, do not end until the pyrite is fully weathered, which can take hundreds to thousands of years. These observations can be generalized to predict future conditions caused by droughts related to El Ni??o and climate change associated with global warming. Already, the time period for dry summers is lengthening in the western US and rainstorms are further apart and more intense when they happen. Consequently, flushing of inactive or active mine sites and mineralized but unmined sites will cause larger sudden increases in concentrations that will be an ever increasing danger to aquatic life with climate change. Higher average concentrations will be observed during longer low-flow periods. Remediation efforts will have to increase the capacity of engineered designs to deal with more extreme conditions, not average conditions of previous years.

Development of chitosan oleate ionic micelles loaded with silver sulfadiazine to be associated with platelet lysate for application in wound healing.

PubMed

Dellera, Eleonora; Bonferoni, Maria Cristina; Sandri, Giuseppina; Rossi, Silvia; Ferrari, Franca; Del Fante, Claudia; Perotti, Cesare; Grisoli, Pietro; Caramella, Carla

2014-11-01

In the treatment of chronic wounds, topical application of anti-infective drugs such as silver sulfadiazine (AgSD) is of primary importance to avoid infections and accelerate wound repair. AgSD is used in burns and chronic wounds for its wide antibacterial spectrum, but presents limitations due to poor solubility and cytotoxicity. In the present work polymeric micelles obtained by self-assembling of chitosan ionically modified by interaction with oleic acid were developed as carriers for AgSD to overcome the drawbacks of the drug. The AgSD loaded micelles were intended to be associated in wound healing with platelet lysate (PL), a hemoderivative rich in growth factors. Unloaded micelles demonstrated good compatibility with both fibroblasts and PL. The relevance of chitosan concentration and of the ratio between chitosan and oleic acid to the drug loading and the particle size of nanoparticles was studied. A marked increase (up to 100 times with respect to saturated solution) of AgSD concentration in micelle dispersion was obtained. Moreover, the encapsulation reduced the cytotoxic effect of the drug towards fibroblasts and the drug incompatibility with PDGF-AB (platelet derived growth factor), chosen as representative of platelet growth factors. Copyright © 2014. Published by Elsevier B.V.

Development and Characterization of a High-Solids Deacetylation Process

DOE PAGES

Shekiro, III, Joseph; Chen, Xiaowen; Smith, Holly; ...

2016-05-20

Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted atmore » low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factor - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shekiro, III, Joseph; Chen, Xiaowen; Smith, Holly

Dilute-acid pretreatment has proven to be a robust means of converting herbaceous feedstock to fermentable sugars. However, it also releases acetic acid, a known fermentation inhibitor, from acetyl groups present in the biomass. A mild, dilute alkaline extraction stage was implemented prior to acid pretreatment to separate acetic acid from the hydrolysate sugar stream. This step, termed deacetylation, improved the glucose and xylose yields from enzymatic hydrolysis and ethanol yields from fermentation of the sugars relative to the control experiments using dilute-acid pretreatment of native corn stover without deacetylation. While promising, deacetylation as it was historically practiced is conducted atmore » low solids loadings, and at fixed conditions. Thus, many questions have been left unanswered, including the relationship between sodium hydroxide and solids loading, and acetate and xylan solubilization, as well as the impact of temperature and residence time on the process efficacy. A central composite experiment was designed to evaluate the impact of solids loading, sodium hydroxide loading, reaction time and temperature during deacetylation on the acetate and xylan solubilization of corn stover. Using the ANOVA test, it became apparent that neither of the responses was significantly impacted by the solids loading, while the reaction time was a minor factor - the responses were largely driven by reaction temperature and the sodium hydroxide loading. Based on the results, we successfully demonstrated the ability to transition the low-solids (10 % w/w) deacetylation process to a higher-solids process (30 % w/w) with minimal impact on the ability to extract acetate from biomass. Conditions were selected to minimize xylose loss during deacetylation, while also removing 70 % of acetyl groups. The impact of selected conditions on the enzymatic hydrolysis and fermentation was further investigated. In conclusion, evaluation of the whole-process impact demonstrated that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

A novel nanofiber Cur-loaded polylactic acid constructed by electrospinning

NASA Astrophysics Data System (ADS)

Thu Trang Mai, Thi; Thu Thuy Nguyen, Thi; Duong Le, Quang; Ngoan Nguyen, Thi; Cham Ba, Thi; Binh Nguyen, Hai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan; Park, Jun Seo

2012-06-01

Curcumin (Cur), extracted from the Curcuma longa L. plant, is well known for its anti-tumor, anti-oxidant, anti-inflammatory and anti-bacterial properties. Nanofiber mats of polylactic acid (PLA) loading Cur (5 wt%) were fabricated by electrospinning (e-spinning). Morphology and structure of the fibers were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The diameters of the obtained fibers varied from 200 to 300 nm. The release capacity of curcumin from curcumin-loaded PLA fibers was investigated in phosphate buffer saline (PBS) containing ethanol. After 24 h, 50% of the curcumin was released from curcumin-loaded PLA fibers. These results of electrospun (e-spun) fibers exhibit the potential for biomedical application.

A Comparative Study of Stabilizing Effect and Antioxidant Activity of Different Antioxidants on Levodopa-Loaded Liposomes.

PubMed

García Esteban, Elena; Cózar-Bernal, María José; Rabasco Álvarez, Antonio M; González-Rodríguez, María Luisa

2018-06-11

The aim of this study was to evaluate the stability of levodopa liposomes co-loaded with three different antioxidants (curcumin, ascorbic acid and superoxide dismutase (SOD)). For this purpose, multilamellar liposomes were prepared. Curcumin was added into the lipid bilayer while ascorbic acid and SOD were placed into the aqueous phase. The influence of preparation technique and surface charge were also investigated. Vesicles were characterized and free radical scavenging potential was determined. From stability study, ascorbic acid showed better stabilizing effect. These co-loaded liposomes also exhibited potential radical scavenging activity where ascorbic acid played a key role. From the study of different preparation techniques and charge, we concluded that cationic liposomes made by Thin Layer Evaporation following extrusion offered the best physicochemical and stability properties. A dual mechanism of these liposomes implies the chemical stabilization of levodopa (dose reduction) and the antioxidant effect, with a preventive effect on Parkinson´s disease.

Effects of Macroporous Resin Size on Candida antarctica Lipase B Adsorption, Fraction of Active Molecules, and Catalytic Activity for Polyester Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen,B.; Miller, E.; Miller, L.

2007-01-01

Methyl methacrylate resins with identical average pore diameter (250 {angstrom}) and surface area (500 m{sup 2}/g) but with varied particle size (35 to 560-710 {mu}m) were employed to study how immobilization resin particle size influences Candida antarctica Lipase B (CALB) loading, fraction of active sites, and catalytic properties for polyester synthesis. CALB adsorbed more rapidly on smaller beads. Saturation occurred in less than 30 s and 48 h for beads with diameters 35 and 560-710 {mu}m, respectively. Linearization of adsorption isotherm data by the Scatchard analysis showed for the 35 {mu}m resin that: (1) CALB loading at saturation was wellmore » below that required to form a monolayer and fully cover the support surface and (2) CALB has a high affinity for this resin surface. Infrared microspectroscopy showed that CALB forms protein loading fronts for resins with particle sizes 560-710 and 120 {mu}m. In contrast, CALB appears evenly distributed throughout 35 {mu}m resins. By titration with p-nitrophenyl n-hexyl phosphate (MNPHP), the fraction of active CALB molecules adsorbed onto resins was <50% which was not influenced by particle size. The fraction of active CALB molecules on the 35 {mu}m support increased from 30 to 43% as enzyme loading was increased from 0.9 to 5.7% (w/w) leading to increased activity for {epsilon}-caprolactone ({epsilon}-CL) ring-opening polymerization. At about 5% w/w CALB loading, by decreasing the immobilization support diameter from 560-710 to 120, 75, and 35 {mu}m, conversion of {epsilon}-CL % to polyester increased (20 to 36, 42, and 61%, respectively, at 80 min). Similar trends were observed for condensation polymerizations between 1,8-octanediol and adipic acid.« less

A polymeric prodrug of 5-fluorouracil-1-acetic acid using a multi-hydroxyl polyethylene glycol derivative as the drug carrier.

PubMed

Li, Man; Liang, Zhen; Sun, Xun; Gong, Tao; Zhang, Zhirong

2014-01-01

Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives.

pH-responsive polymeric micelles of poly(ethylene glycol)-b-poly(alkyl(meth)acrylate-co-methacrylic acid): influence of the copolymer composition on self-assembling properties and release of candesartan cilexetil.

PubMed

Satturwar, Prashant; Eddine, Mohamad Nasser; Ravenelle, François; Leroux, Jean-Christophe

2007-03-01

The objective of the present study was to investigate the influence of chemical structure and molecular weight of pH-sensitive block copolymers on their self-assembling properties, the loading and the release of candesartan cilexetil (CDN). Block copolymers of poly(ethylene glycol) and t-butyl methacrylate, iso-butyl acrylate, n-butyl acrylate or propyl methacrylate were synthesized by atom transfer radical polymerization. pH-sensitivity was obtained by hydrolysis of t-butyl groups. The poorly water-soluble drug CDN was incorporated in the micelles and the in vitro drug release was evaluated as a function of pH. The critical aggregation concentration of hydrolyzed copolymers (pK(a)=6.2-6.6) was higher compared to the unhydrolyzed ones. Dynamic light scattering studies and atomic force microscopy images revealed uniform size micelles with aggregation numbers ranging from 60 to 160. The entrapment efficiency of CDN was generally found to be above 90%, with drug loading levels reaching approximately 20% (w/w). Differential scanning calorimetry studies showed the amorphous nature of entrapped CDN. The release of CDN from pH-sensitive micelles was triggered upon an increase in pH from 1.2 to 7.2. These findings suggest that the PEG-b-poly(alkyl(meth)acrylate-co-methacrylic acid)s can self-assemble to form micelles which exhibit high loading capacities for CDN and release the drug in a pH-dependent fashion.

[Taurine as a regulator of fluid-electrolyte balance and arterial pressure].

PubMed

Ciechanowska, B

1997-01-01

Taurine is a sulfonic beta-amino acid which occurs in the highest concentration in the brain, the retina and in the myocardium. In cardiomyocytes it presents about 50% of free amino acids and plays a role as an osmoregulator, an inotropic factor and has an antiarrhythmic property. Moreover, taurine lowers arterial pressure by extension of diuresis and by vasodilatation. Similar effect on the vascular system and arterial pressure is exerted by atrial natriuretic peptide (ANP). Increase of both ANP secretion and myocardial taurine concentration is present in the same diseases as congestive cardiac failure, hypertension and hypernatremia. The aim of the study was the evaluation of general taurine depletion, caused by making the rats drink guanidinoethyl sulfonate (GES)--an inhibitor of taurine transport affecting fluid balance and arterial pressure as well as plasma ANP concentration under normal conditions and after increase of sodium load. The 103 male Wistar rats weighing 250-300 g were used. The animals were separated into 5 groups. Control group received tap water to drink. Group II was sodium-loaded by drinking 171 mmol/l NaCl. In group III depletion of taurine was obtained by the intake of 60 mmol/l GES. Rats in group IV were drinking 60 mmol/l GES in 171 mmol/l NaCl. Group V was made to drink 200 mmol/l taurine in 171 mmol/l NaCl. All animals had standard food and were able at any time to drink. Duration of the experiment was 20 days. At the onset and after 10 and 20 days the rats were weighed and their systolic blood pressure was measured by tail plethysmography. After 10 and 20 days of the study, plasma and myocardium taurine concentration, ANP, hematocrit, plasma osmolity, natremia, kalemia, urea and creatinine concentrations were determined. Taking GES for 20 days led to 43% decrease of plasma taurine and its myocardium content about 50% as compared to control group (Tab. 2). High, statistically significant correlation (r = 0.50, p < 0.001) between myocardium taurine and plasma ANP was found. The animals with taurine depletion had significantly lower (about 30%) plasma ANP concentration (Tab. 3), higher natremia (Tab. 4) and their arterial pressure increased due to sodium load. Systolic pressure was 11 mm Hg higher in that group in comparison to control and other groups (Tab. 1). However, the sodium-loading of the rats that drank taurine solution led to an increase of hematocrit, plasma osmolity, urea concentration and body mass gain as compared to control group, but without any arterial pressure increase. The sodium-loaded rats with normal plasma and myocardium taurine concentration were affected in a similar manner. The rats with higher myocardium taurine concentration had lower heart mass index. Results of this work lead to the following conclusions: 1. Depletion of taurine in hearts of examined rats leads to a decrease of plasma atrial natriuretic peptide (ANP) concentration in plasma. 2. ANP secretion caused by salt loading is lower in animals with taurine depletion than in normal animals. 3. Sodium-loading of animals with taurine depletion leads to hypernatremia and to an increase of arterial pressure. 4. Addition of taurine to animals loaded with sodium may lead to their dehydration.

The Effects of Phosphonic Acids in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

James, Keith Edward

Novel methods for the construction of dye-sensitized solar cells (DSSCs) were developed. A thin dense underlayer of TiO2 was applied on fluorine-doped tin oxide (FTO) glass using as a precursor Tyzor AA-105. Subsequently a mesoporous film of P-25 TiO2 was applied by spreading a suspension uniformly over the surface of the underlayer and allowing the plate to slowly dry while resting on a level surface. After sintering at 500° C slides were treated with TCPP as a sensitizing dye and assembled into DSSCs. A novel method was used to seal the cells; strips of ParafilmRTM were used as spacers between the electrodes and to secure the electrodes together. The cells were filled with a redox electrolyte and sealed by dipping into molten paraffin. A series of phosphonic acids and one arsonic acid were employed as coadsorbates in DSSCs. The coadsorbates were found to compete for binding sites, resulting in lower levels of dye adsorption. The resulting loss of photocurrent was not linear with the reduction of dye loading, and in some cases photocurrent and efficiency were higher for cells with lower levels of dye loading. Electrodes were treated with coadsorbates by procedures including pre-adsorption, simultaneous (sim-adsorption), and post-adsorption, using a range of concentrations and treatment times and a variety of solvents. Most cells were tested using an iodide-triiodide based electrolyte (I3I-1) but some cells were tested using electrolytes based on a Co(II)/Co(III) redox couple (CoBpy electrolytes). Phosphonic acid post-adsorbates increased the Voc of cells using CoBpy electrolytes but caused a decrease in the Voc of cells using I3I-1 electrolyte. Phosphonic acids as sim-adsorbates resulted in a significant increase in efficiency and Jsc, and they show promise as a treatment for TCPP DSSCs.

Interface actions between TiO2 and porous diatomite on the structure and photocatalytic activity of TiO2-diatomite

NASA Astrophysics Data System (ADS)

Xia, Yue; Li, Fangfei; Jiang, Yinshan; Xia, Maosheng; Xue, Bing; Li, Yanjuan

2014-06-01

TiO2-diatomite photocatalysts were prepared by sol-gel process with various pre-modified diatomite. In order to obtain diatomite with different surface characteristics, two modification approaches including calcination and phosphoric acid treatment on the micro-structure of diatomite are introduced. The photocatalysts were characterized by XRD, XPS, nitrogen adsorption-desorption isotherms and micromorphology analysis. The results indicate that, compared with pure TiO2, the anatase-to-rutile phase transition temperature of TiO2 loaded on diatomite carrier is significantly increased to nearly 900 °C, depending on the different pretreatment method of diatomite. The photocatalytic activities of different samples were evaluated by their degradation rate of methyl orange (MO) dye under UV and visible-light irradiation. The samples prepared by phosphoric acid pretreatment method exhibit the highest photocatalytic activity. After 90 min of UV irradiation, about 90% of MO is decomposed by the best effective photocatalyst. And after 8 h visible-light irradiation, nearly 60% of MO is decomposed by the same sample. Further mechanism investigation reveals that the H3PO4 pretreatment process can obviously change the surface features of diatomite carrier, cause the formation of Si-O-Ti bond, increase the binding strength between TiO2 and diatomite, restrain crystal growth of loaded TiO2, and thus form thermal-stable mesoporous structure at the granular spaces. It helps to build micro-, meso- and macro-porous hierarchical porous structure in TiO2-diatomite, and improves the charge and mass transfer efficiency during catalyzing process, resulting in the significantly increased photocatalytic activity of TiO2-diatomite pretreated by phosphoric acid.

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size1[OPEN

PubMed Central

Wang, Liang; Lu, Qingtao

2015-01-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. PMID:26504138

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size.

PubMed

Wang, Liang; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

2015-12-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. © 2015 American Society of Plant Biologists. All Rights Reserved.

Predicting recovery from acid rain using the micro-spatial heterogeneity of soil columns downhill the infiltration zone of beech stemflow: introduction of a hypothesis.

PubMed

Berger, Torsten W; Muras, Alexander

Release of stored sulfur may delay the recovery of soil pH from Acid Rain. It is hypothesized that analyzing the micro-spatial heterogeneity of soil columns downhill of a beech stem enables predictions of soil recovery as a function of historic acid loads and time. We demonstrated in a very simplified approach, how these two different factors may be untangled from each other using synthetic data. Thereafter, we evaluated the stated hypothesis based upon chemical soil data with increasing distance from the stem of beech trees. It is predicted that the top soil will recover from acid deposition, as already recorded in the infiltration zone of stemflow near the base of the stem. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed.

Hydroisomerization of n-Hexane Using Acidified Metal-Organic Framework and Platinum Nanoparticles.

PubMed

Sabyrov, Kairat; Jiang, Juncong; Yaghi, Omar M; Somorjai, Gabor A

2017-09-13

Exceptionally high surface area and ordered nanopores of a metal-organic framework (MOF) are exploited to encapsulate and homogeneously disperse a considerable amount of phosphotungstic acid (PTA). When combined with platinum nanoparticles positioned on the external surface of the MOF, the construct shows a high catalytic activity for hydroisomerization of n-hexane, a reaction requiring hydrogenation/dehydrogenation and moderate to strong Brønsted acid sites. Characterization of the catalytic activity and acidic sites as a function of PTA loading demonstrates that both the concentration and strength of acidic sites are highest for the catalyst with the largest amount of PTA. The MOF construct containing 60% PTA by weight produces isoalkanes with 100% selectivity and 9-fold increased mass activity as compared to a more traditional aluminosilicate catalyst, further demonstrating the capacity of the MOF to contain a high concentration of active sites necessary for the isomerization reaction.

Microspheres for the oral delivery of insulin: preparation, evaluation and hypoglycaemic effect in streptozotocin-induced diabetic rats.

PubMed

Zhang, Huan; Wang, Weimei; Li, Haoran; Peng, Yi; Zhang, Zhiqing

2018-01-01

Insulin-loaded microspheres were prepared by alternating deposition film layers that were composed of insulin and poly(vinyl sulfate) potassium on the surface of poly(lactic acid) (PLA) microspheres. The preparation of the insulin-loaded microspheres was optimized by an orthogonal test design, and the relationship between drug loading (DL) and film layers was studied. The particle size, DL and encapsulation efficiency of the obtained insulin-loaded microspheres with 10 films were 5.25 ± 0.15 µm, 111.33 ± 1.15 mg/g and 33.7 ± 0.19%, respectively. Following this, the physical characteristics of the insulin-loaded microspheres were investigated. The results from scanning electron microscopy and a laser particle size analyzer (LPSA) indicated the spherical morphology, rough surface and increasing particle sizes of the insulin-loaded microspheres, which were compared to those of PLA microspheres. An in vitro release study showed that the insulin-loaded microspheres were stable in HCl solution (pH 1.0) and released insulin slowly in phosphate-buffered solution (pH 6.8). Finally, the drug efficacy of the prepared insulin-loaded microspheres via oral administration was evaluated in rats with diabetes induced by streptozotocin, and an obvious dose-dependent hypoglycemic effect was observed. This preliminary data could illustrate the prospect of using microspheres for the oral delivery of insulin.

Pediatric tuberculosis-human immunodeficiency virus co-infection in the United Kingdom highlights the need for better therapy monitoring tools: a case report.

PubMed

Evangelopoulos, Dimitrios; Whittaker, Elizabeth; Honeyborne, Isobella; McHugh, Timothy D; Klein, Nigel; Shingadia, Delane

2017-02-26

Tuberculosis is an infection that requires at least 6 months of chemotherapy in order to clear the bacteria from the patient's lungs. Usually, therapeutic monitoring is dependent on smear microscopy where a decline in acid-fast bacilli is observed. However, this might not be indicative of the actual decline of bacterial load and thus other tools such as culture and molecular assays are required for patient management. Here, we report the case of a 12-year-old Black African boy co-infected with tuberculosis and human immunodeficiency virus who remained smear culture positive and liquid culture negative for a prolonged period of time following chemotherapy. In order to determine whether there was any live bacteria present in his specimens, we applied the newly developed molecular bacterial load assay that detects the presence of 16S ribosomal ribonucleic acid derived from the bacteria. Using this methodology, we were able to quantify his bacterial load and inform the management of his treatment in order to reduce the disease burden. Following this intervention he went on to make a complete recovery. This case report highlights the value of improved biomarkers for monitoring the treatment of tuberculosis and the role of molecular assays such as the molecular bacterial load assay applied here. The molecular bacterial load assay detects bacterial ribonucleic acid which corresponds closely with the number of live bacilli as compared with polymerase chain reaction that detects deoxyribonucleic acid and may include dead bacteria.

In vitro characterization of pH-sensitive azithromycin-loaded methoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) micelles.

PubMed

Teng, Fangfang; Deng, Peizong; Song, Zhimei; Zhou, Feilong; Feng, Runliang; Liu, Na

2017-06-15

In order to improve azithromycin's antibacterial activity in acidic medium, monomethoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) copolymer was synthesized through allylation, free radical addition, ring-opening polymerization and amidation reactions with methoxy poly (ethylene glycol) as raw material. Drug loading capacity and encapsulation efficiency of azithromycin-loaded micelles prepared via thin film hydration method were 11.58±0.86% and 96.06±1.93%, respectively. The drug-loaded micelles showed pH-dependent property in the respects of particle size, zeta potential at the range of pH 5.5-7.8. It could control drug in vitro release and demonstrate higher release rate at pH 6.0 than that at pH 7.4. In vitro antibacterial experiment indicated that the activity of azithromycin-loaded micelles against S. aureus was superior to free azithromycin in medium at both pH 6.0 and pH 7.4. Using fluorescein as substitute with pH-dependent fluorescence decrease property, laser confocal fluorescence microscopy analysis confirmed that cellular uptake of micelles was improved due to protonation of copolymer's imidazole groups at pH 6.0. The enhanced cellular uptake and release of drug caused its activity enhancement in acidic medium when compared with free drug. The micellar drug delivery system should be potential application in the field of bacterial infection treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Characterization of polylactic co-glycolic acid nanospheres modified with PVA and DDAB

NASA Astrophysics Data System (ADS)

Mulia, Kamarza; Satyapertiwi, Dwiantari; Devina, Ranee; Krisanti, Elsa

2017-02-01

The common treatment for diabetic retinopathy is corticosteroids intravitreal injection that sometimes lead to complications. Dexamethasone-loaded polylactic co-glycolic acid (PLGA) nanospheres, modified with dioctadecyldimethylammonium bromide (DDAB) as the cationic surfactant, is expected to prolong drug retention time. Zeta potential of the PLGA nanospheres prepared using non-ionic surfactant PVA and DDAB confirmed the cationic surfactant increase the surface charge of the PLGA nanospheres. The optimal formulation based on the particle size and high positive surface charge was the PLGA-DDAB nanospheres. SEM analysis showed spherical morphology of the nanospheres having diameter 626.9 ± 98.01 nm positive zeta potential of +22.5 mV.

Photophysics of aggregated 9-methylthiacarbocyanine bound to polyanions

NASA Astrophysics Data System (ADS)

Chibisov, Alexander K.; Görner, Helmut

2002-05-01

The photophysical properties of 3,3 '-diethyl-9-methylthiacarbocyanine (DTC) were studied in the presence of polystyrene sulfonate (PSS), polyacrylic acid (PAA) and polymethacrylic acid (PMA). The absorption spectra reflect a monomer/dimer equilibrium in neat aqueous solution and a shift towards bound H-aggregates, bound dimers and bound monomers on increasing the ratio of polyanion residue to dye concentrations ( r). These equilibria also determine the photodeactivation modes of DTC. The fluorescence intensity is reduced, when dimers and aggregates are present and strongly enhanced for low dye loading ( r=10 4). In contrast, the quantum yield of intersystem crossing is enhanced for bound dimers ( r=10 3).

Epichlorohydrin induced biochemical changes in the rose-ringed parakeet, Psittacula krameri Scopoli.

PubMed

Hans, B; Kaur, S; Sangha, G K

1999-08-01

Intraperitoneal administration of epichlorohydrin (ECH) at the dose level of 20 and 50 mg/kg body weight inhibited spermatogenesis in the testis of parakeet during breeding season. A total load of 60 mg/kg body weight of ECH given on 3 consecutive days proved to be lethal. Testicular proteins, nucleic acids (DNA and RNA), phospholipids and acid phosphatase activity were decreased, while the lipids, total cholesterol and alkaline phosphatase activity increased after ECH administration. The results suggest that the testicular atrophy caused by ECH was associated with an alteration in the activities of macromolecules and enzymes related to specific events of spermatogenesis.

pH-Sensitive PEGylated liposomes for delivery of an acidic dinitrobenzamide mustard prodrug: Pathways of internalization, cellular trafficking and cytotoxicity to cancer cells.

PubMed

Yang, Mimi M; Wilson, William R; Wu, Zimei

2017-01-10

This paper aims to develop and evaluate a pH-sensitive PEGylated liposomal (pPSL) system for tumor-targeted intracellular delivery of SN25860, a weakly acidic, poorly water-soluble dinitrobenzamide mustard prodrug which is activated by the E. coli nitroreductase nfB. pPSL and non pH-sensitive liposomes (nPSL), as reference, were formulated by thin-film hydration; an active drug loading method was developed with the aid of solubilizers. Cytotoxicity was evaluated in an nfsB-transfected EMT6 mouse mammary carcinoma cell line. Cellular uptake of liposomes was evaluated by both high performance liquid chromatography and flow cytometry. Intracellular trafficking was visualised by confocal microscopy. High drug loading (7.0±0.2% w/w) was achieved after systematic optimization of drug loading conditions. pPSL-SN25860 demonstrated a 21 and 24- fold increase in antiproliferative potency compared to nPSL-SN25860 and free drug, respectively. Cells treated with pPSL had a 1.6-2.5- fold increase in intracellular drug concentration compared to nPSL. This trend was consistent with flow cytometry results. Cells treated with chlorpromazine demonstrated reduced uptake of both nPSL (40%) and pPSL (46%), indicating clathrin-mediated endocytosis was the major pathway. Confocal microscopy showed that pPSL had not only undergone faster and greater endocytosis than nPSL but was also homogeneously distributed in the cytosol and nuclei suggesting endosome escape, in contrast to nPSL. Copyright © 2016 Elsevier B.V. All rights reserved.

Extended release of hyaluronic acid from hydrogel contact lenses for dry eye syndrome.

PubMed

Maulvi, Furqan A; Soni, Tejal G; Shah, Dinesh O

2015-01-01

Current dry eye treatment includes delivering comfort enhancing agents to the eye via eye drops, but low residence time of eye drops leads to low bioavailability. Frequent administration leads to incompliance in patients, so there is a great need for medical device such as contact lenses to treat dry eye. Studies in the past have demonstrated the efficacy of hyaluronic acid (HA) in the treatment of dry eyes using eye drops. In this paper, we present two methods to load HA in hydrogel contact lenses, soaking method and direct entrapment. The contact lenses were characterized by studying their optical and physical properties to determine their suitability as extended wear contact lenses. HA-laden hydrogel contact lenses prepared by soaking method showed release up to 48 h with acceptable physical and optical properties. Hydrogel contact lenses prepared by direct entrapment method showed significant sustained release in comparison to soaking method. HA entrapped in hydrogels resulted in reduction in % transmittance, sodium ion permeability and surface contact angle, while increase in % swelling. The impact on each of these properties was proportional to HA loading. The batch with 200-μg HA loading showed all acceptable values (parameters) for contact lens use. Results of cytotoxicity study indicated the safety of hydrogel contact lenses. In vivo pharmacokinetics studies in rabbit tear fluid showed dramatic increase in HA mean residence time and area under the curve with lenses in comparison to eye drop treatment. The study demonstrates the promising potential of delivering HA through contact lenses for the treatment of dry eye syndrome.

Effect of L-aspartic acid on the growth, structure and spectral studies of Zinc (tris) Thiourea Sulphate (ZTS) single crystals

NASA Astrophysics Data System (ADS)

Samuel, Bincy Susan; Krishnamurthy, R.; Rajasekaran, R.

2014-11-01

Single crystals of pure and L-aspartic acid doped Zinc (Tris) Thiourea Sulphate (ZTS) were grown from aqueous solution by solution growth method. The cell parameters and structure of the grown crystals were determined by X-ray diffraction studies. The presence of functional group in the compound has been confirmed by FTIR and FT-Raman analysis. The optical transparency range has been studied through UV-Vis spectroscopy. TGA/DTA studies show thermal stability of the grown crystals. Microhardness study reveals that the hardness number (Hv) increases with load for pure and doped ZTS crystals. Dielectric studies have been carried out and the results are discussed. The second harmonic generation was confirmed for L-aspartic acid doped ZTS which is greater than pure ZTS.

Incorporation of Active DNA/Cationic Polymer Polyplexes into Hydrogel Scaffolds

PubMed Central

Lei, Yuguo; Huang, Suxian; Sharif-Kashani, Pooria; Chen, Yong; Kavehpour, Pirouz; Segura, Tatiana

2010-01-01

The effective and sustained delivery of DNA and siRNAs locally would increase the applicability of gene therapy in tissue regeneration and cancer therapy. One promising approach is to use hydrogel scaffolds to encapsulate and deliver nucleotides in the form of nanoparticles to the disease sites. However, this approach is currently limited by the inability to load concentrated and active gene delivery nanoparticles into the hydrogels due to the severe nanoparticle aggregation during the loading process. Here, we present a process to load concentrated and un-aggregated non-viral gene delivery nanoparticles, using DNA/polyethylene imine (PEI) polyplexes as an example, into neutral polyethylene glycol (PEG), negatively charged hyaluronic acid (HA) and protein fibrin hydrogels crosslinked through various chemistries. The encapsulated polyplexes are highly active both in vitro and in vivo. We believe this process will significantly advance the applications of hydrogel scaffold mediated non-viral gene delivery in tissue regeneration and cancer therapy. PMID:20822811

Anti-transferrin receptor-modified amphotericin B-loaded PLA-PEG nanoparticles cure Candidal meningitis and reduce drug toxicity.

PubMed

Tang, Xiaolong; Liang, Yong; Zhu, Yongqiang; Xie, Chunmei; Yao, Aixia; Chen, Li; Jiang, Qinglin; Liu, Tingting; Wang, Xiaoyu; Qian, Yunyun; Wei, Jia; Ni, Wenxuan; Dai, Jingjing; Jiang, Zhenyou; Hou, Wei

2015-01-01

Fatal fungal infections in central nervous system (CNS) can occur through hematogenous spread or direct extension. At present, hydrophobic amphotericin B (AMB) is the most effective antifungal drug in clinical trials. However, AMB is hydrophobic and therefore penetrates poorly into the CNS, and therapeutic levels of AMB are hard to achieve. The transferrin receptor (TfR/CD71) located at the blood-brain barrier mediates transferrin transcytosis. In order to enhance the receptor-mediated delivery of AMB into CNS with therapeutic level, an anti-TfR antibody (OX26)-modified AMB-loaded PLA (poly[lactic acid])-PEG (polyethylene glycol)-based micellar drug delivery system was constructed. The prepared OX26-modified AMB-loaded nanoparticles (OX26-AMB-NPs) showed significant reduction of CNS fungal burden and an increase of mouse survival time. In conclusion, OX26-AMB-NPs represent a promising novel drug delivery system for intracerebral fungal infection.

Limited toxicity of NH(x) pulses on an early and late successional tropical seagrass species: interactions with pH and light level.

PubMed

Christianen, M J A; van der Heide, T; Bouma, T J; Roelofs, J G M; van Katwijk, M M; Lamers, L P M

2011-07-01

Seagrasses have declined at a global scale due to light reduction and toxicity events, caused by eutrophication and increased sediment loading. Although several studies have tested effects of light reduction and toxicants on seagrasses, there is at present no information available on their interacting effects. In a full-factorial 5-day laboratory experiment, we studied short-term interactive effects of light conditions, pH and reduced nitrogen (NH(x)) in the water layer, mimicking pulses of river discharge, on the tropical early successional species Halodule uninervis and the late successional species Thalassia hemprichii. In contrast to recent results reported for the temperate species Zostera marina, increased NH(x) supply did not affect leaf mortality or photochemical efficiency in H. uninervis and in 7 out of 8 treatments for T. hemprichii. However, both tropical species demonstrated striking differences in nitrogen accumulation, free amino acid composition and free NH₃ accumulation. The increase in tissue nitrogen content was two times higher for H. uninervis than for T. hemprichii. Nitrogen stored as free amino acids (especially asparagine) only increased in H. uninervis. High pH only affected T. hemprichii, but only when not shaded, by doubling its free NH₃ concentrations, concomitantly decreasing its photosynthetic efficiency. Our results indicate that the early successional H. uninervis has higher tolerance to high NH(x) loads as compared to the late successional T. hemprichii. H. uninervis was better able to avoid toxic internal NH(x) levels by further assimilating glutamine into asparagine in contrast to T. hemprichii. Moreover, both tropical species seem to cope much better with high NH(x) than the temperate Z. marina. The implications for the distribution and succession of seagrass species under high nutrient loads are discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Improved Anticancer Effect of Magnetite Nanocomposite Formulation of GALLIC Acid (Fe₃O₄-PEG-GA) Against Lung, Breast and Colon Cancer Cells.

PubMed

Rosman, Raihana; Saifullah, Bullo; Maniam, Sandra; Dorniani, Dena; Hussein, Mohd Zobir; Fakurazi, Sharida

2018-02-02

Lung cancer, breast cancer and colorectal cancer are the most prevalent fatal types of cancers globally. Gallic acid (3,4,5-trihydroxybenzoic acid) is a bioactive compound found in plants and foods, such as white tea, witch hazel and it has been reported to possess anticancer, antioxidant and anti-inflammatory properties. In this study we have redesigned our previously reported anticancer nanocomposite formulation with improved drug loading based on iron oxide magnetite nanoparticles coated with polyethylene glycol and loaded with anticancer drug gallic acid (Fe₃O₄-PEG-GA). The in vitro release profile and percentage drug loading were found to be better than our previously reported formulation. The anticancer activity of pure gallic acid (GA), empty carrier (Fe₃O₄-PEG) nanocarrier and of anticancer nanocomposite (Fe₃O₄-PEG-GA) were screened against human lung cancer cells (A549), human breast cancer cells (MCF-7), human colon cancer cells (HT-29) and normal fibroblast cells (3T3) after incubation of 24, 48 and 72 h using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay. The designed formulation (Fe₃O₄-PEG-GA) showed better anticancer activity than free gallic acid (GA). The results of the in vitro studies are highly encouraging to conduct the in vivo studies.

Effect of sialic acid loss on dendritic cell maturation

PubMed Central

Crespo, Hélio J; Guadalupe Cabral, M; Teixeira, Alexandra V; Lau, Joseph T Y; Trindade, Hélder; Videira, Paula A

2009-01-01

Sialic acids are key structural determinants and contribute to the functionality of a number of immune cell receptors. Previously, we demonstrated that differentiation of human dendritic cells (DCs) is accompanied by an increased expression of sialylated cell surface structures, putatively through the activity of the ST3Gal.I and ST6Gal.I sialyltransferases. Furthermore, DC endocytosis was reduced upon removal of the cell surface sialic acid residues by neuraminidase. In the present work, we evaluate the contribution of the sialic acid modifications in DC maturation. We demonstrate that neuraminidase-treated human DCs have increased expression of major histocompatibility complex (MHC) and costimulatory molecules, increased gene expression of specific cytokines and induce a higher proliferative response of T lymphocytes. Together, the data suggest that clearance of cell surface sialic acids contributes to the development of a T helper type 1 proinflammatory response. This postulate is supported by mouse models, where elevated MHC class II and increased maturation of specific DC subsets were observed in DCs harvested from ST3Gal.I−/− and ST6Gal.I−/− mice. Moreover, important qualitative differences, particularly in the extent of reduced endocytosis and in the peripheral distribution of DC subsets, existed between the ST3Gal.I−/− and ST6Gal.I−/− strains. Together, the data strongly suggest not only a role of cell surface sialic acid modifications in maturation and functionality of DCs, but also that the sialic acid linkages created by different sialyltransferases are functionally distinct. Consequently, with particular relevance to DC-based therapies, cell surface sialylation, mediated by individual sialyltransferases, can influence the immunogenicity of DCs upon antigen loading. PMID:19740323

Heterogeneous Chemistry of HONO on Liquid Sulfuric Acid: A New Mechanism of Chlorine Activation on Stratospheric Sulfate Aerosols

NASA Technical Reports Server (NTRS)

Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

1996-01-01

Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) Was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO(+)HSO4(-). At temperatures below 230 K, NO(+)HSO4(-) was observed to be stable and accumulated in concentrated solutions (less than 70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (less than 70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (ClNO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4. In the stratosphere, ClNO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT.

Possible mechanism of structural incorporation of Al into diatomite during the deposition process I. Via a condensation reaction of hydroxyl groups.

PubMed

Liu, Dong; Yu, Wenbin; Deng, Liangliang; Yuan, Weiwei; Ma, Lingya; Yuan, Peng; Du, Peixin; He, Hongping

2016-01-01

The structural incorporation of aluminium (Al) into diatomite is investigated by preparing several Al-diatomite composites by loading an Al precursor, hydroxyl aluminum polymer (Al13), onto the surface of diatomite and heating at various temperatures. The results indicate that Al was incorporated and implanted into the structure of diatomite by the condensation reaction of the hydroxyl groups of Al13 and diatomite, and the Si-O-Al(OH) groups were formed during the condensation reaction. Al incorporation by the condensation reaction of hydroxyl groups of Al13 with single silanols of diatomite occurred more readily than that with geminal silanols. The Al incorporation increased solid acidity of diatomite after Al incorporation. The acidity improvement was various for different types of acid sites, depending on the preparation temperature of the Al-incorporated diatomite. Both Brønsted and Lewis acid sites increased greatly after heating at 250 and 350 °C, but only L acid sites significantly improved after heating at 500 °C. These results demonstrate that the structural incorporation of Al(3+) ions into diatomite can occur by the condensation reaction of the hydroxyl groups of the Al precursors and diatomite. Moreover, the rich solid acid sites of Al-incorporated diatomite show its promising application as a solid acid catalyst. Copyright © 2015 Elsevier Inc. All rights reserved.

Adipose differentiation-related protein regulates lipids and insulin in pancreatic islets

PubMed Central

Faleck, D. M.; Ali, K.; Roat, R.; Graham, M. J.; Crooke, R. M.; Battisti, R.; Garcia, E.; Ahima, R. S.

2010-01-01

The excess accumulation of lipids in islets is thought to contribute to the development of diabetes in obesity by impairing β-cell function. However, lipids also serve a nutrient function in islets, and fatty acids acutely increase insulin secretion. A better understanding of lipid metabolism in islets will shed light on complex effects of lipids on β-cells. Adipose differentiation-related protein (ADFP) is localized on the surface of lipid droplets in a wide range of cells and plays an important role in intracellular lipid metabolism. We found that ADFP was highly expressed in murine β-cells. Moreover, islet ADFP was increased in mice on a high-fat diet (3.5-fold of control) and after fasting (2.5-fold of control), revealing dynamic changes in ADFP in response to metabolic cues. ADFP expression was also increased by addition of fatty acids in human islets. The downregulation of ADFP in MIN6 cells by antisense oligonucleotide (ASO) suppressed the accumulation of triglycerides upon fatty acid loading (56% of control) along with a reduction in the mRNA levels of lipogenic genes such as diacylglycerol O-acyltransferase-2 and fatty acid synthase. Fatty acid uptake, oxidation, and lipolysis were also reduced by downregulation of ADFP. Moreover, the reduction of ADFP impaired the ability of palmitate to increase insulin secretion. These findings demonstrate that ADFP is important in regulation of lipid metabolism and insulin secretion in β-cells. PMID:20484013

Effect of PLGA as a polymeric emulsifier on preparation of hydrophilic protein-loaded solid lipid nanoparticles.

PubMed

Xie, ShuYu; Wang, SiLiang; Zhao, BaoKai; Han, Chao; Wang, Ming; Zhou, WenZhong

2008-12-01

Most proteins are hydrophilic and poorly encapsulated into the hydrophobic matrix of solid lipid nanoparticles (SLN). To solve this problem, poly (lactic-co-glycolic acid) (PLGA) was utilized as a lipophilic polymeric emulsifier to prepare hydrophilic protein-loaded SLN by w/o/w double emulsion and solvent evaporation techniques. Hydrogenated castor oil (HCO) was used as a lipid matrix and bovine serum albumin (BSA), lysozyme and insulin were used as model proteins to investigate the effect of PLGA on the formulation of the SLN. The results showed that PLGA was essential for the primary w/o emulsification. In addition, the stability of the w/o emulsion, the encapsulation efficiency and loading capacity of the nanoparticles were enhanced with the increase of PLGA concentration. Furthermore, increasing PLGA concentration decreased zeta potential significantly but had no influence on particle size of the SLN. In vitro release study showed that PLGA significantly affected the initial burst release, i.e. the higher the content of PLGA, the lower the burst release. The released proteins maintained their integrity and bioactivity as confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and biological assay. These results demonstrated that PLGA was an effective emulsifier for the preparation of hydrophilic protein-loaded SLN.

Recovery of acetic acid from dilute aqueous solutions using catalytic dehydrative esterification with ethanol.

PubMed

Yagyu, Daisuke; Ohishi, Tetsuo; Igarashi, Takeshi; Okumura, Yoshikuni; Nakajo, Tetsuo; Mori, Yuichiro; Kobayashi, Shū

2013-03-01

We have developed a direct esterification of aqueous acetic acid with ethanol (molar ratio=1:1) catalyzed by polystyrene-supported or homogeneous sulfonic acids toward the recovery of acetic acid from wastewater in chemical plants. The equilibrium yield was significantly increased by the addition of toluene, which had a high ability to extract ethyl acetate from the aqueous phase. It was shown that low-loading and alkylated polystyrene-supported sulfonic acid efficiently accelerated the reaction. These results suggest that the construction of hydrophobic reaction environments in water was critical in improving the chemical yield. Addition of inorganic salts was also effective for the reaction under not only biphasic conditions (toluene-water) but also toluene-free conditions, because the mutual solubility of ethyl acetate and water was suppressed by the salting-out effect. Among the tested salts, CaCl(2) was found to be the most suitable for this reaction system. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced oral bioavailability and in vivo antioxidant activity of chlorogenic acid via liposomal formulation.

PubMed

Feng, Yingshu; Sun, Congyong; Yuan, Yangyang; Zhu, Yuan; Wan, Jinyi; Firempong, Caleb Kesse; Omari-Siaw, Emmanuel; Xu, Yang; Pu, Zunqin; Yu, Jiangnan; Xu, Ximing

2016-03-30

In the present study, a formulation system consisting of cholesterol and phosphatidyl choline was used to prepare an effective chlorogenic acid-loaded liposome (CAL) with an improved oral bioavailability and an increased antioxidant activity. The developed liposomal formulation produced regular, spherical and multilamellar-shaped distribution nanoparticles. The pharmacokinetic analysis of CAL compared with chlorogenic acid (CA), showed a higher value of Cmax(6.42 ± 1.49 min versus 3.97 ± 0.39 min) and a delayed Tmax(15 min versus 10 min), with 1.29-fold increase in relative oral bioavailability. The tissue distribution in mice also demonstrated that CAL predominantly accumulated in the liver which indicated hepatic targeting potential of the drug. The increased activities of antioxidant enzymes (Total Superoxide Dismutase (T-SOD) and Glutathione Peroxidase (GSH-Px)) and total antioxidant capacity (T-AOC), in addition to decreased level of malondialdehyde (MDA) in CCl4-induced hepatotoxicity study further revealed that CAL exhibited significant hepatoprotective and antioxidant effects. Collectively, these findings present a liposomal formulation with significantly improved oral bioavailability and an increased in vivo antioxidant activity of CA. Copyright © 2016 Elsevier B.V. All rights reserved.

Treatment of purified terephthalic acid wastewater using a bio-waste-adsorbent bagasse fly ash (BFA).

PubMed

Verma, Shilpi; Prasad, Basheshwar; Mishra, Indra Mani

2017-01-01

Purified terephthalic acid (PTA) plant of a petrochemical unit generates wastewater having high pollution load. Acid treatment of this wastewater reduces the chemical oxygen demand (COD) load by more than 50%, still leaving substantial COD load (>1500 mg/L) which should be removed. The present study reports on the use of a bio-waste-adsorbent bagasse fly ash (BFA) for the reduction of COD and other recalcitrant acids from this wastewater. The BFA showed basic character and was mesoporous with a BET specific surface area of 82.4 m 2 /g. Optimum conditions for the adsorptive treatment of acid-pretreated PTA wastewater were found to be as follows: initial pH (pH i ) = 4, BFA dosage = 15 g/L, and contact time = 3 h. Adsorption treatment resulted in 58.2% removal of COD, 96.3% removal of terephthalic acid (TA), and 99.9% removal of benzoic acid (BA). TA and BA were removed from the pretreated PTA wastewater through precipitation and sedimentation of un-dissociated acid molecules inside the mesopores of the BFA. The results showed that the COD removed by the BFA followed pseudo-second-order kinetics. Equilibrium sorption data were best correlated by the Freundlich isotherm. The process of adsorptive removal of COD was found to be exothermic. The change in the Gibbs free energy was found to be negative, suggesting that the adsorption process is spontaneous and feasible for the treatment of PTA wastewater.

Characterization of a dual specificity aryl acid adenylation enzyme with dual function in nikkomycin biosynthesis.

PubMed

Moon, Mary; Van Lanen, Steven G

2010-09-01

Nikkomycin Z is a dipeptide antifungal antibiotic characterized by two nonproteinogenic amino acids, nikkomycin C(Z) and 4-(4'-hydroxy-2'-pyridinyl)-homothreonine (HPHT). The HPHT scaffold is assembled by an aldol reaction between 2-oxobutyrate and picolinaldehyde, the latter of which is derived from picolinic acid that is activated and loaded to coenzyme A by the aryl-activating adenylation enzyme, NikE. We now provide evidence that NikE is also involved in the activation and loading of the alpha-keto acid precursor, 4-(2'-pyridinyl)-2-oxo-4-hydroxyisovalerate (POHIV), to a phosphopantetheinyl group of an acyl carrier protein domain of NikT. POHIV was synthesized using Escherichia coli 2-dehydro-3-deoxy-phosphogluconate aldolase, and phenylalanine dehydrogenase from Bacillus sp. NRRL B-14911 was used to prepare the alpha-amino acid, 4-(2'-pyridinyl)-homothreonine (PHT). Using the carboxylic acid-dependent, ATP-[(32)P]PP(i) exchange assay, NikE is shown to activate both picolinic acid and POHIV but not PHT. Furthermore, NikE loads POHIV to holo-NikT to generate a new thioester-linked intermediate, which was not observed using a NikT(S33A) mutant. Thus, NikE activates two distinct carboxylic acids to form two new thioester intermediates, one of which is subsequently reduced to the aldehyde and the other that likely serves as a substrate for the aminotransferase domain of NikT prior to condensation with nikkomycin C(Z) to yield the dipeptide. Copyright 2010 Wiley Periodicals, Inc.

Anaerobic digestion of glycerol and co-digestion of glycerol and pig manure.

PubMed

Nuchdang, Sasikarn; Phalakornkule, Chantaraporn

2012-06-30

The potential of glycerol obtained from transesterification of waste cooking oil as a main carbon source for biogas production was investigated. The glycerol was highly contaminated with oils and fats and was pretreated with sulfuric acid. Using a carbon source of glucose as a control, we compared biogas production from the acid-treated glycerol in a synthetic medium and the acid-treated glycerol mixed with pig manure. The anaerobic digestion of acid-treated glycerol with supplement in a synthetic medium was found to be satisfactory at organic loading rates (OLR) between 1.3, 1.6 and 2.6 g chemical oxygen demand (COD) L(-1) d(-1). The maximum methane yield of 0.32 L at Standard temperature and pressure (STP) g(-1) COD removal was achieved at an OLR of 1.6 g COD L(-1) d(-1) and the methane content was 54% on an average. At a higher organic loading rate of 5.4 g COD L(-1) d(-1), the propionic acid to acetic acid ratio was higher than the critical threshold limit for metabolic imbalance. Anaerobic digestion of acid-treated glycerol with pig manure was also investigated at the COD ratio of 80:20 (glycerol:pig manure). The anaerobic digestion of acid-treated glycerol with pig manure was found to be satisfactory at organic loading rates between 1.3, 1.7, 2.9 and 5.0 g COD L(-1) d(-1) in terms of COD reduction (>80%) and methane content of (62% on an average). However, the biogas production rate was found to significantly decrease at the highest load. The maximum methane yield of 0.24 L STP g(-1) COD removal was achieved at an OLR of 1.3 g COD L(-1) d(-1). Copyright © 2012 Elsevier Ltd. All rights reserved.

Association of Cortical β-Amyloid with Erythrocyte Membrane Monounsaturated and Saturated Fatty Acids in Older Adults at Risk of Dementia.

PubMed

Hooper, C; De Souto Barreto, P; Payoux, P; Salabert, A S; Guyonnet, S; Andrieu, S; Sourdet, S; Delrieu, J; Vellas, B

2017-01-01

We examined the relationships between erythrocyte membrane monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs) and cortical β-amyloid (Aβ) load in older adults reporting subjective memory complaints. This is a cross-sectional study using data from the Multidomain Alzheimer Preventive Trial (MAPT); a randomised controlled trial. French community dwellers aged 70 or over reporting subjective memory complaints, but free from a diagnosis of clinical dementia. Participants of this study were 61 individuals from the placebo arm of the MAPT trial with data on erythrocyte membrane fatty acid levels and cortical Aβ load. Cortical-to-cerebellar standard uptake value ratios were assessed using [18F] florbetapir positron emission tomography (PET). Fatty acids were measured in erythrocyte cell membranes using gas chromatography. Associations between erythrocyte membrane MUFAs and SFAs and cortical Aβ load were explored using adjusted multiple linear regression models and were considered significant at p ≤ 0.005 (10 comparisons) after correction for multiple testing. We found no significant associations between fatty acids and cortical Aβ load using multiple linear regression adjusted for age, sex, education, cognition, PET-scan to clinical assessment interval, PET-scan to blood collection interval and apolipoprotein E (ApoE) status. The association closest to significance was that between erythrocyte membrane stearic acid and Aβ (B-coefficient 0.03, 95 % CI: 0.00,0.05, p = 0.05). This association, although statistically non-significant, appeared to be stronger amongst ApoE ε4 carriers (B-coefficient 0.04, 95 % CI: -0.01,0.09, p = 0.08) compared to ApoE ε4 non-carriers (B-coefficient 0.02, 95 % CI: -0.01,0.05, p = 0.18) in age and sex stratified analysis. Future research in the form of large longitudinal observational study is needed to validate our findings, particularly regarding the potential association of stearic acid with cortical Aβ.

Critical levels and loads and the regulation of industrial emissions in northwest British Columbia, Canada

NASA Astrophysics Data System (ADS)

Williston, P.; Aherne, J.; Watmough, S.; Marmorek, D.; Hall, A.; de la Cueva Bueno, P.; Murray, C.; Henolson, A.; Laurence, J. A.

2016-12-01

Northwest British Columbia, Canada, a sparsely populated and largely pristine region, is targeted for rapid industrial growth owing to the modernization of an aluminum smelter and multiple proposed liquefied natural gas (LNG) facilities. Consequently, air quality in this region is expected to undergo considerable changes within the next decade. In concert, the increase in LNG capacity driven by gas production from shale resources across North America has prompted environmental concerns and highlighted the need for science-based management decisions regarding the permitting of air emissions. In this study, an effects-based approach widely-used to support transboundary emissions policy negotiations was used to assess industrial air emissions in the Kitimat and Prince Rupert airsheds under permitted and future potential industrial emissions. Critical levels for vegetation of SO2 and NO2 and critical loads of acidity and nutrient nitrogen for terrestrial and aquatic ecosystems were estimated for both regions and compared with modelled concentration and deposition estimates to identify the potential extent and magnitude of ecosystem impacts. The critical level for SO2 was predicted to be exceeded in an area ranging from 81 to 251 km2 in the Kitimat airshed owing to emissions from an existing smelter, compared with <1 km2 in Prince Rupert under the lowest to highest emissions scenarios. In contrast, the NO2 critical level was not exceeded in Kitimat, and ranged from 4.5 to 6 km2 in Prince Rupert owing to proposed LNG related emissions. Predicted areal exceedance of the critical load of acidity for soil ranged from 1 to 28 km2 in Kitimat and 4-10 km2 in Prince Rupert, while the areal exceedance of empirical critical load for nutrient N was predicted to be greater in the Prince Rupert airshed (20-94 km2) than in the Kitimat airshed (1-31 km2). The number of lakes that exceeded the critical load of acidity did not vary greatly across emissions scenarios in the Kitimat (21-23 out of 80 sampled lakes) and Prince Rupert (0 out of 35 sampled lakes) airsheds. While critical loads have been widely used to underpin international emissions reductions of transboundary pollutants, it is clear that they can also play an important role in managing regional air emissions. In the current study, exceedance of critical levels and loads suggests that industrial emissions from the nascent LNG export sector may require careful regulation to avoid environmental impacts. Emissions management from LNG export facilities in other regions should consider critical levels and loads analyses to ensure industrial development is synergistic with ecosystem protection. While recognizing uncertainties in dispersion modelling, critical load estimates, and subsequent effects, the critical levels and loads approach is being used to inform regulatory decisions in British Columbia to prevent impacts that have been well documented in other regions.

Surface chemistry and catalytic performance of amorphous NiB/Hβ catalyst for n-hexane isomerization

NASA Astrophysics Data System (ADS)

Chen, Jinshe; Cai, Tingting; Jing, Xiaohui; Zhu, Lijun; Zhou, Yulu; Xiang, Yuzhi; Xia, Daohong

2016-12-01

The amorphous NiB nanoparticles were synthesized and a novel type of NiB/Hβ catalyst was prepared for the isomerization of n-hexane. The optimum preparation conditions were investigated and the effect of preparation conditions on the surface chemistry information of catalysts was characterized by XRD, N2 sorption studies, XPS, TPD and other related means. It was demonstrated that the loading amounts of NiB have effect on textural properties and the acid properties of surface. The loading amounts of NiB were also related to the amount of strong Lewis acid sites and the ratios of weak acid to strong acid of samples. Meanwhile, calcination temperatures of samples were closely associated with the structure of active components that function as metal centers. When the loading amount of NiB was 5 wt.% and calcination temperature was 200 °C, the catalyst had proper surface acidity sites and metal active sites to provide suitable synergistic effects. The mechanism for n-hexane isomerization was also investigated and the existence of unique structure of Bsbnd Nisbnd H was proved, which could provide good hydrogenation-dehydrogenation functions.

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium.

PubMed

Jalil, Aamir; Khan, Samiullah; Naeem, Fahad; Haider, Malik Suleman; Sarwar, Shoaib; Riaz, Amna; Ranjha, Nazar Muhammad

2017-01-01

In present investigation new formulations of Sodium Alginate/Acrylic acid hydrogels with high porous structure were synthesized by free radical polymerization technique for the controlled drug delivery of analgesic agent to colon. Many structural parameters like molecular weight between crosslinks ( M c ), crosslink density ( M r ), volume interaction parameter ( v 2, s ), Flory Huggins water interaction parameter and diffusion coefficient ( Q ) were calculated. Water uptake studies was conducted in different USP phosphate buffer solutions. All samples showed higher swelling ratio with increasing pH values because of ionization of carboxylic groups at higher pH values. Porosity and gel fraction of all the samples were calculated. New selected samples were loaded with the model drug (diclofenac potassium).The amount of drug loaded and released was determined and it was found that all the samples showed higher release of drug at higher pH values. Release of diclofenac potassium was found to be dependent on the ratio of sodium alginate/acrylic acid, EGDMA and pH of the medium. Experimental data was fitted to various model equations and corresponding parameters were calculated to study the release mechanism. The Structural, Morphological and Thermal Properties of interpenetrating hydrogels were studied by FTIR, XRD, DSC, and SEM.

Effect of microbial activities on stored raw buffalo hide.

PubMed

Shede, P N; Kanekar, P P; Polkade, A V; Sarnaik, S S; Dhakephalkar, P K; Chiplonkar, S A; Nilegaonkar, S S

2009-11-01

'Keeping qualities' of hides are dependent on the total microbial flora associated with the hides and the biochemical changes brought about by these microorganisms during short-term storage at ambient temperature (28 +/- 2 degrees C). It was evident that within first 24 hr of hide's ambient storage, bacterial load was raised to 8.8 log cfu g(-1) hide from 6.1 log cfu g(-1) hide. Nonlinear parabolic increase in release of hydroxyproline and tyrosine from stored hide was observed starting from 0 hr and confirming proteolytic activities. Continuous release of CO2 from the stored hide suggested its mineralization. Exponential release of free fatty acids during storage indicated simultaneous lipolysis. Thus the process of biodegradation during the course of ambient storage of hide piece was found to progress steadily and seems to be interrelated as well as very complex. During the storage period, the liquefaction of hide piece was also observed visually within 96 hr. Present studies of assessment of bacterial activities on hide with respect to total bacterial load, release of amino acids, free fatty acids and evolved CO2 provide data that can be used to formulate and evaluate hide curing agent(s) other than salt, thus rendering leather industry a platform to design bio-based technologies for efficient and ecofriendly preservation of raw materials.

Development of a robust pH-sensitive polyelectrolyte ionomer complex for anticancer nanocarriers

PubMed Central

Lim, Chaemin; Youn, Yu Seok; Lee, Kyung Soo; Hoang, Ngoc Ha; Sim, Taehoon; Lee, Eun Seong; Oh, Kyung Taek

2016-01-01

A polyelectrolyte ionomer complex (PIC) composed of cationic and anionic polymers was developed for nanomedical applications. Here, a poly(ethylene glycol)–poly(lactic acid)–poly(ethylene imine) triblock copolymer (PEG–PLA–PEI) and a poly(aspartic acid) (P[Asp]) homopolymer were synthesized. These polyelectrolytes formed stable aggregates through electrostatic interactions between the cationic PEI and the anionic P(Asp) blocks. In particular, the addition of a hydrophobic PLA and a hydrophilic PEG to triblock copolyelectrolytes provided colloidal aggregation stability by forming a tight hydrophobic core and steric hindrance on the surface of PIC, respectively. The PIC showed different particle sizes and zeta potentials depending on the ratio of cationic PEI and anionic P(Asp) blocks (C/A ratio). The doxorubicin (dox)-loaded PIC, prepared with a C/A ratio of 8, demonstrated pH-dependent behavior by the deprotonation/protonation of polyelectrolyte blocks. The drug release and the cytotoxicity of the dox-loaded PIC (C/A ratio: 8) increased under acidic conditions compared with physiological pH, due to the destabilization of the formation of the electrostatic core. In vivo animal imaging revealed that the prepared PIC accumulated at the targeted tumor site for 24 hours. Therefore, the prepared pH-sensitive PIC could have considerable potential as a nanomedicinal platform for anticancer therapy. PMID:26955270

Targeted antitumoral dehydrocrotonin nanoparticles with L-ascorbic acid 6-stearate.

PubMed

Frungillo, Lucas; Martins, Dorival; Teixeira, Sérgio; Anazetti, Maristela Conti; Melo, Patrícia da Silva; Durán, Nelson

2009-12-01

Tumoral cells are known to have a higher ascorbic acid uptake than normal cells. Therefore, the aim of this study was to obtain polymeric nanoparticles containing the antitumoral compound trans-dehydrocrotonin (DHC) functionalized with L-ascorbic acid 6-stearate (AAS) to specifically target this system tumoral cells. Nanoparticle suspensions (NP-AAS-DHC) were prepared by the nanoprecipitation method. The systems were characterized for AAS presence by thin-layer chromatography and for drug loading (81-88%) by UV-Vis spectroscopy. To further characterize these systems, in vitro release kinetics, size distribution (100-140 nm) and Zeta potential by photon-correlation spectroscopic method were used. In vitro toxicity against HL60 cells was evaluated by tetrazolium reduction and Trypan blue exclusion assays. Cell death by apoptosis was quantified and characterized by flow cytometry and caspase activity. Zeta potential analyses showed that the system has a negatively charged outer surface and also indicate that AAS is incorporated on the external surface of the nanoparticles. In vitro release kinetics assay showed that DHC loaded in nanoparticles had sustained release behavior. In vitro toxicity assays showed that NP-AAS-DHC suspension was more effective as an antitumoral than free DHC or NP-DHC and increased apoptosis induction by receptor-mediated pathway. 2009 Wiley-Liss, Inc. and the American Pharmacists Association