SPITFIRE-1

NASA Technical Reports Server (NTRS)

Ryntz, Edward F.

1995-01-01

The purpose of this effort is to develop low-cost rapid forming superplastic aluminum that will be evaluated in pilot production trials for automotive SPF components. The alloy development study conducted under SPITFIRE-1 showed that the addition of CU or Mn to the base 5083 aluminum alloy refined the grain size, leading to enhanced superplastic properties. In SPITFIRE-2, these alloy variants will be further refined and studied to meet the target properties established earlier in the program. Mechanical properties, component forming and post-forming properties will be evaluated. Also, the alloy production process, including thermomechanical processing (TMP) optimization to reduce production cost, will be investigated during SPITFIRE-2. After identifying preferred compositions and production processing, the most promising alloy will be manufactured into production coils for verification during SPITFIRE-3. Components will be produced from these coils in SPITFIRE-4, and the process and component performance will be assessed.

Grain Boundary Engineering and Air Oxidation Behavior of Alloy 690

NASA Astrophysics Data System (ADS)

Xu, Peng; Zhao, Liang Y.; Sridharan, Kumar; Allen, Todd R.

Grain boundary engineering (GBE) was performed on nickel-based alloy 690 by thermomechanical processing (TMP) to alter the grain boundary character distribution (GBCD). It was found that 5% and 35% thickness reduction in single and multiple steps followed by solution annealing and water quench yielded a high fraction of special boundaries. The total length fraction of the low ∑ CSL (coincidence site lattice) was as high as 87.2%. The grain boundary network was disrupted after the TMP treatment, and the average grain size calculated after exclusion of special twin boundaries can be as much as 5 times larger than the as-received (AR) sample. The GBE sample showed better oxidation resistance compared to the AR sample during the long term air oxidation. In the cyclic oxidation test, both AR and GBE samples showed a mass gain at the beginning of the test which was then followed by a mass loss. The mass change of GBE samples oscillated after the first couple cycles, while the AR sample became relatively stable. The oxide film most likely consists of duplex structures with one stable layer that was formed inside and one unstable layer that was formed outside. The stable inner layer was the protective layer and prevented alloy 690 from further oxidation.

Performance assessment of a submerged membrane bioreactor using a novel microbial consortium.

PubMed

Chon, Kangmin; Lee, Kyungpyo; Kim, In-Soo; Jang, Am

2016-06-01

The performance of a submerged membrane bioreactor (MBR) with and without a novel microbial consortium (NMBR vs. CMBR) was compared to provide deeper insights into the effects of changes in water quality and dissolved organic matter (DOM) characteristics by a novel microbial consortium on the fouling characteristics of MBR processes. Despite similar operating conditions and identical DOM properties in the feed waters, NMBR exhibited a lower propensity to release polysaccharide-like compounds with low molecular weight by bacterial activities compared to CMBR. These compounds have a great fouling potential for MBR processes. Therefore, an increase in the transmembrane pressure (TMP) of NMBR (normalized TMP (TMP/TMP0): 1.14) was much slower and less significant than that observed in CMBR (TMP/TMP0: 2.61). These observations imply that the novel microbial consortium can efficiently mitigate membrane fouling by hydrophilic DOM in MBR processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The chemical properties and microbial community characterization of the thermophilic microaerobic pretreatment process.

PubMed

Fu, Shan-Fei; He, Shuai; Shi, Xiao-Shuang; Katukuri, Naveen Reddy; Dai, Meng; Guo, Rong-Bo

2015-12-01

Thermophilic microaerobic pretreatment (TMP) was recently reported as an efficient pretreatment method of anaerobic digestion (AD). In this study, the chemical properties and microbial community were characterized to reveal how TMP working. Compared with thermophilic treatment under anaerobic condition (TMP0), cellulase activity obviously improved under microaerobic condition (TMP1), which was 10.9-49.0% higher than that of TMP0. Reducing sugar, SCOD and VFAs concentrations of TMP1 were 2.6-8.9%, 1.8-4.8% and 13.8-24% higher than those of TMP0, respectively. TMP gave obvious rise to phylum Firmicutes, which associated with extracellular enzymes production. The proportion of class Bacilli (belongs to phylum Firmicutes and mainly acts during hydrolysis) in TMP1 was 124.89% higher than that of TMP0, which reflected the greater hydrolytic ability under microaerobic condition. The improved abundance of phylum Firmicutes (especially class Bacilli, order Bacillales) under microaerobic condition could be the fundamental reason for the improved AD performance of thermophilic microaerobic pretreated corn straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decomposition of sulfamethoxazole and trimethoprim by continuous UVA/LED/TiO2 photocatalysis: Decomposition pathways, residual antibacterial activity and toxicity.

PubMed

Cai, Qinqing; Hu, Jiangyong

2017-02-05

In this study, continuous LED/UVA/TiO 2 photocatalytic decomposition of sulfamethoxazole (SMX) and trimethoprim (TMP) was investigated. More than 90% of SMX and TMP were removed within 20min by the continuous photoreactor (with the initial concentration of 400ppb for each). The removal rates of SMX and TMP decreased with higher initial antibiotics loadings. SMX was much easier decomposed in acidic condition, while pH affected little on TMP's decomposition. 0.003% was found to be the optimum H 2 O 2 dosage to enhance SMX photocatalytic decomposition. Decomposition pathways of SMX and TMP were proposed based on the intermediates identified by using LC-MS-MS and GC-MS. Aniline was identified as a new intermediate generated during SMX photocatalytic decomposition. Antibacterial activity study with a reference Escherichia coli strain was also conducted during the photocatalytic process. Results indicated that with every portion of TMP removed, the residual antibacterial activity decreased by one portion. However, the synergistic effect between SMX and TMP tended to slow down the antibacterial activity removal of SMX and TMP mixture. Chronic toxicity studies conducted with Vibrio fischeri exhibited 13-20% bioluminescence inhibition during the decomposition of 1ppm SMX and 1ppm TMP, no acute toxicity to V. fischeri was observed during the photocatalytic process. Copyright © 2016 Elsevier B.V. All rights reserved.

Efficient mineralization of the antibiotic trimethoprim by solar assisted photoelectro-Fenton process driven by a photovoltaic cell.

PubMed

Zhang, Yanyu; Wang, Aimin; Tian, Xiujun; Wen, Zhenjun; Lv, Hanjiao; Li, Desheng; Li, Jiuyi

2016-11-15

In this study, a novel self-sustainable solar assisted photoelectro-Fenton (SPEF) system driven by a solar photovoltaic cell was developed for the efficient mineralization of antibiotic trimethoprim (TMP) in water. A comparative degradation of 200mgL(-1) TMP by RuO2/Ti anodic oxidation (AO), anodic oxidation with H2O2 electrogeneration (AO-H2O2), electro-Fenton (EF) and SPEF was investigated. SPEF was proved to exhibit the highest oxidation power, i.e., more than 80% TOC was removed after 360min SPEF treatment of 200mgL(-1) of TMP under optimal conditions at pH 3.0, 1.0mM Fe(2+) and 18mAcm(-2). Influences of current density, pH, initial Fe(2+) and initial TMP concentration on SPEF process were also studied. Ten aromatic intermediates generated from hydroxylation, carbonylation and demethylation reactions were identified using UPLC-QTOF-MS/MS system during the SPEF treatment, together with three carboxylic acids (oxamic, oxalic and formic acids) and two inorganic ions (NH4(+) and NO3(-)) measured. Therefore, a reasonable pathway of TMP degradation in SPEF process was proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Degradation of trimethoprim by gamma irradiation in the presence of persulfate

NASA Astrophysics Data System (ADS)

Zhang, Zhonglei; Yang, Qi; Wang, Jianlong

2016-10-01

The degradation and mineralization of trimethoprim (TMP) by gamma irradiation was investigated in the presence of persulfate (PS). The TMP was degraded at initial concentration of 20 mg/L in aqueous solution with addition of 0, 0.5, 1, 1.5, 2 mM persulfate respectively. The effect of pH values (6.5, 7.5 and 8.5) on TMP degradation was also determined. The experimental results showed that the degradation and mineralization of TMP could be significantly enhanced by persulfate at acidic condition (pH=6.5). Several intermediate products generated during gamma irradiation process through hydroxylation, demethylation and cleavage were identified using liquid chromatography with tandem mass spectrometry (HPLC-MS). The degradation pathway of TMP was tentatively proposed based on the identification of intermediate products.

Tetramethylpyrazine promotes SH-SY5Y cell differentiation into neurons through epigenetic regulation of Topoisomerase IIβ.

PubMed

Yan, Y; Zhao, J; Cao, C; Jia, Z; Zhou, N; Han, S; Wang, Y; Xu, Y; Zhao, J; Yan, Y; Cui, H

2014-10-10

Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Recently, it has been reported that TMP enhances neurogenesis, and promotes neural stem cell differentiation toward neurons. However, its molecular basis remains unknown. Topoisomerase IIβ (TopoIIβ) is a nuclear enzyme with an essential role in neuronal development. This study aimed to investigate whether TopoIIβ is involved in TMP-induced neuronal differentiation. We examined the effect of TMP on neuronal differentiation of SH-SY5Y cells. It was found that TMP inhibited cell proliferation and induced G0/G1 cell cycle arrest. TMP promoted SH-SY5Y cells to differentiate toward post-mitotic neurons characterized by long, out-branched neurites and up-regulated neuronal markers, microtubule-associated protein 2 (MAP2) and tau. Meanwhile, we demonstrated that TopoIIβ was highly expressed following TMP treatment. To unravel how TMP affects TopoIIβ expression, two chromatin active markers, acetylated histone H3 (Ac-H3) and acetylated histone H4 (Ac-H4) were examined in this study. Our data showed that the levels of Ac-H3 and Ac-H4 were positively correlated with TopoIIβ expression in the processes of neuronal differentiation. We further performed chromatin immunoprecipitation (ChIP) analysis and identified that TMP enhanced the recruitment of Ac-H3 and Ac-H4 to the TopoIIβ gene promoter region. Therefore, we concluded that TMP may stimulate neuronal differentiation of SH-SY5Y cells through epigenetic regulation of TopoIIβ. These results suggest a novel molecular mechanism underlying TMP-promoted neuronal differentiation. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Recovery process of shear wave velocities of volcanic soil in central Mashiki Town after the 2016 Kumamoto earthquake revealed by intermittent measurements of microtremor

NASA Astrophysics Data System (ADS)

Hata, Yoshiya; Yoshimi, Masayuki; Goto, Hiroyuki; Hosoya, Takashi; Morikawa, Hitoshi; Kagawa, Takao

2017-05-01

An earthquake of JMA magnitude 6.5 (foreshock) hit Kumamoto Prefecture, Japan, at 21:26 JST on April 14, 2016. Subsequently, an earthquake of JMA magnitude 7.3 (main shock) hit Kumamoto and Oita Prefectures at 1:25 JST on April 16, 2016. The two epicenters were located adjacent to central Mashiki Town, and both events caused significantly strong motions. The heavy damage including collapse of residential houses was concentrated in "Sandwich Area" between Prefectural Route 28 and Akitsu River. During the main shock, we have successfully observed strong motions at TMP03 in Sandwich Area. Simultaneously with installation of the seismograph at TMP03 on April 15, 2016, between the foreshock and the main shock, a microtremor measurement was taken. After the main shock, intermittent measurements of microtremor at TMP03 were also taken within December 6, 2016. As the result, recovery process of shear wave velocities of volcanic soil at TMP03 before/after the main shock was revealed by time history of peak frequencies of the microtremor H/V spectra. Using results of original PS logging tests at proximity site of TMP03 on July 28, 2016, the applicability for the shear wave velocities to TMP03 was then confirmed based on similarity between the theoretical and monitored H/V spectra.

Novel Tandem Biotransformation Process for the Biosynthesis of a Novel Compound, 4-(2,3,5,6-Tetramethylpyrazine-1)-4′-Demethylepipodophyllotoxin▿

PubMed Central

Tang, Ya-Jie; Zhao, Wei; Li, Hong-Mei

2011-01-01

According to the structure of podophyllotoxin and its structure-function relationship, a novel tandem biotransformation process was developed for the directional modification of the podophyllotoxin structure to directionally synthesize a novel compound, 4-(2,3,5,6-tetramethylpyrazine-1)-4′-demethylepipodophyllotoxin (4-TMP-DMEP). In this novel tandem biotransformation process, the starting substrate of podophyllotoxin was biotransformed into 4′-demethylepipodophyllotoxin (product 1) with the demethylation of the methoxyl group at the 4′ position by Gibberella fujikuroi SH-f13, which was screened out from Shennongjia prime forest humus soil (Hubei, China). 4′-Demethylepipodophyllotoxin (product 1) was then biotransformed into 4′-demethylpodophyllotoxone (product 2) with the oxidation of the hydroxyl group at the 4 position by Alternaria alternata S-f6, which was screened out from the gathered Dysosma versipellis plants in the Wuhan Botanical Garden, Chinese Academy of Sciences. Finally, 4′-demethylpodophyllotoxone (product 2) and ligustrazine were linked with a transamination reaction to synthesize the target product 4-TMP-DMEP (product 3) by Alternaria alternata S-f6. Compared with podophyllotoxin (i.e., a 50% effective concentration [EC50] of 529 μM), the EC50 of 4-TMP-DMEP against the tumor cell line BGC-823 (i.e., 0.11 μM) was significantly reduced by 5,199 times. Simultaneously, the EC50 of 4-TMP-DMEP against the normal human proximal tubular epithelial cell line HK-2 (i.e., 0.40 μM) was 66 times higher than that of podophyllotoxin (i.e., 0.006 μM). Furthermore, compared with podophyllotoxin (i.e., log P = 0.34), the water solubility of 4-TMP-DMEP (i.e., log P = 0.66) was significantly enhanced by 94%. For the first time, the novel compound 4-TMP-DMEP with superior antitumor activity was directionally synthesized from podophyllotoxin by the novel tandem biotransformation process developed in this work. PMID:21398491

Effects of transmembrane hydraulic pressure on performance of forward osmosis membranes.

PubMed

Coday, Bryan D; Heil, Dean M; Xu, Pei; Cath, Tzahi Y

2013-03-05

Forward osmosis (FO) is an emerging membrane separation process that continues to be tested and implemented in various industrial water and wastewater treatment applications. The growing interests in the technology have prompted laboratories and manufacturers to adopt standard testing methods to ensure accurate comparison of membrane performance under laboratory-controlled conditions; however, standardized methods might not capture specific operating conditions unique to industrial applications. Experiments with cellulose triacetate (CTA) and polyamide thin-film composite (TFC) FO membranes demonstrated that hydraulic transmembrane pressure (TMP), common in industrial operation of FO membrane elements, could affect membrane performance. Experiments were conducted with three FO membranes and with increasing TMP up to a maximum of 50 psi (3.45 bar). The feed solution was a mixture of salts and the draw solution was either a NaCl solution or concentrated seawater at similar osmotic pressure. Results revealed that TMP minimally affected water flux, reverse salt flux (RSF), and solute rejection of the CTA membrane. However, water flux through TFC membranes might slightly increase with increasing TMP, and RSF substantially declines with increasing TMP. It was observed that rejection of feed constituents was influenced by TMP and RSF.

Advances of two-stage riser catalytic cracking of heavy oil for maximizing propylene yield (TMP) process.

PubMed

Chaohe, Yang; Xiaobo, Chen; Jinhong, Zhang; Chunyi, Li; Honghong, Shan

Two-stage riser catalytic cracking of heavy oil for maximizing propylene yield (TMP) process proposed by State Key Laboratory of Heavy oil Processing, China University of Petroleum, can remarkably enhance the propylene yield and minimize the dry gas and coke yields, and obtain high-quality light oils (gasoline and diesel). It has been commercialized since 2006. Up to now, three TMP commercial units have been put into production and other four commercial units are under design and construction. The commercial data showed that taking paraffinic based Daqing (China) atmospheric residue as the feedstock, the propylene yield reached 20.31 wt%, the liquid products yield (the total yield of liquefied petroleum gas, gasoline, and diesel) was 82.66 wt%, and the total yield of dry gas and coke was 14.28 wt%. Moreover, the research octane number of gasoline could be up to 96.

A Preliminary Testability Analysis of the Mil-STD-1862 Architecture.

DTIC Science & Technology

1981-08-01

NEXT Iget address of successor of P (S) and check for write rights tmp2 = read(tmpl,word,M.w) NEXT read(tmp,word,M.w) NEXT Icheck write rights...read(tmp+4,word,M.w) NEXT Icheck write rights read(tmp2+4,word,M.w) NEXT Icheck write rights I IF tmp<l:0> OR tmpl<l:0> OR tmp2<l:0...address of pred (P) read(tmp2,word,M.w) NEXT Icheck access rights read(tmpl+4,word,M.w) NEXT. Icheck access rights IIF tmp<l:0> OR tmpl<l:0> OR

Integration of ceramic membrane and compressed air-assisted solvent extraction (CASX) for metal recovery.

PubMed

Li, Chi-Wang; Chiu, Chun-Hao; Lee, Yu-Cheng; Chang, Chia-Hao; Lee, Yu-Hsun; Chen, Yi-Ming

2010-01-01

In our previous publications, compressed air-assisted solvent extraction process (CASX) was developed and proved to be kinetically efficient process for metal removal. In the current study, CASX with a ceramic MF membrane integrated for separation of spent solvent was employed to remove and recover metal from wastewater. MF was operated either in crossflow mode or dead-end with intermittent flushing mode. Under crossflow mode, three distinct stages of flux vs. TMP (trans-membrane pressure) relationship were observed. In the first stage, flux increases with increasing TMP which is followed by the stage of stable flux with increasing TMP. After reaching a threshold TMP which is dependent of crossflow velocity, flux increases again with increasing TMP. At the last stage, solvent was pushed through membrane pores as indicated by increasing permeate COD. In dead-end with intermittent flushing mode, an intermittent flushing flow (2 min after a 10-min or a 30-min dead-end filtration) was incorporated to reduce membrane fouling by flush out MSAB accumulated on membrane surface. Effects of solvent concentration and composition were also investigated. Solvent concentrations ranging from 0.1 to 1% (w/w) have no adverse effect in terms of membrane fouling. However, solvent composition, i.e. D(2)EHPA/kerosene ratio, shows impact on membrane fouling. The type of metal extractants employed in CASX has significant impact on both membrane fouling and the quality of filtrate due to the differences in their viscosity and water solubility. Separation of MSAB was the limiting process controlling metal removal efficiency, and the removal efficiency of Cd(II) and Cr(VI) followed the same trend as that for COD.

Superiority of solar Fenton oxidation over TiO2 photocatalysis for the degradation of trimethoprim in secondary treated effluents.

PubMed

Michael, I; Hapeshi, E; Michael, C; Fatta-Kassinos, D

2013-01-01

The overall aim of this work was to examine the degradation of trimethoprim (TMP), which is an antibacterial agent, during the application of two advanced oxidation process (AOP) systems in secondary treated domestic effluents. The homogeneous solar Fenton process (hv/Fe(2+)/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were tested. It was found that the degradation of TMP depends on several parameters such as the amount of iron salt and H2O2, concentration of TiO2, pH of solution, solar irradiation, temperature and initial substrate concentration. The optimum dosages of Fe(2+) and H2O2 for homogeneous ([Fe(2+)] = 5 mg L(-1), [H2O2] = 3.062 mmol L(-1)) and TiO2 ([TiO2] = 3 g L(-1)) for heterogeneous photocatalysis were established. The study indicated that the degradation of TMP during the solar Fenton process is described by a pseudo-first-order reaction and the substrate degradation during the heterogeneous photocatalysis by the Langmuir-Hinshelwood kinetics. The toxicity of the treated samples was evaluated using a Daphnia magna bioassay and was finally decreased by both processes. The results indicated that solar Fenton is more effective than the solar TiO2 process, yielding complete degradation of the examined substrate within 30 min of illumination and dissolved organic carbon (DOC) reduction of about 44% whereas the respective values for the TiO2 process were ∼70% degradation of TMP within 120 min of treatment and 13% DOC removal.

A study of equilibrium and FTIR, SEM/EDS analysis of trimethoprim adsorption onto K10

NASA Astrophysics Data System (ADS)

Bekçi, Zehra; Seki, Yoldaş; Kadir Yurdakoç, M.

2007-02-01

The sorption behavior of K10, a type of montmorillonite for trimethoprim (TMP) drug, was studied by using batch technique under different pH and temperature. The interaction between K10 and TMP was investigated using SEM, and FTIR. It was observed that adsorption was increased between pH 2.5 and 6.3. By performing kinetic experiments, the pseudo-second-order kinetic model provides the best fit for TMP adsorption onto K10 montmorillonite. The sorption of TMP reached the equilibrium state after 6 h sorption time and has been described by using Langmuir, Freundlich and Dubinin-Radushkevich equations to obtain adsorption capacity values. The results indicate that the relative adsorption capacity values ( Kf) are decreasing with the increase of temperature in the range of 298-318 K. The sorption energy values obtained from DR isotherm show that sorption of TMP onto K10 can be explained by ion exchange mechanism at 298, 308 and 318 K. The thermodynamic studies were conducted to find the thermodynamic parameters Δ H°, Δ S° and Δ G°. It was determined that adsorption process is spontaneous and exothermic in nature.

Antibiotics in urinary-tract infections. Sustained change in prescribing habits by practice test and self-reflection: a mixed methods before-after study.

PubMed

Kuehlein, T; Goetz, K; Laux, G; Gutscher, A; Szecsenyi, J; Joos, S

2011-06-01

BACKGROUND The German guideline recommends trimethoprim (TMP) for the treatment of uncomplicated lower-urinary-tract infections (uLUTI) in primary care. In the authors' research network, the participating general practitioners (GPs) were asked why they prescribe mostly quinolones instead. The GPs stated the perception of a high rate of therapy failure of TMP and strongly rejected the guideline. OBJECTIVE To examine prescribing behaviour for uLUTI and whether a practice test of TMP might effect a change in prescribing habits. METHODS The study was conducted using observational and qualitative elements. A first focus-group (n=6) assessed reasons for current prescribing behaviour. In a 3-month practice test, patients with uLUTI were prescribed TMP (150 mg twice for 3 days). In a second focus group, the GPs (n=12) were presented with the results of the practice test. RESULTS The first focus group revealed that prescribing was mainly driven by former hospital training and what was perceived as common therapy. GPs felt no need to change a successful regimen. In the practice test, TMP had a success rate of 94% (84 episodes of uLUTI). The second focus group revealed that the practice test had strongly changed opinions in favour of TMP. Self-reflection and ownership of data acquisition were seen as major contributions for change in prescribing. After the test period, TMP remained the antibiotic most often prescribed. CONCLUSION Internal evidence and peer-group opinion are strong determinants for clinical decisions. A self-conducted practice test, together with self-reflection in a peer group, strongly supports the process of change.

Hyponatraemia associated with trimethoprim use.

PubMed

Khow, Kareeann Sok Fun; Yong, Tuck Yean

2014-03-01

Trimethoprim (TMP) is a commonly prescribed antibiotic with few adverse effects. However on rare occasions, TMP is associated with electrolyte disturbances. As seen in our three patients, TMP can be associated with symptomatic hyponatraemia which required hospitalization. In one of these patients, hyperkalaemia and type 4 renal tubular acidosis were also present. These electrolyte and acid-base disorders were corrected after discontinuation of TMP. A small number of patients with TMP-induced electrolyte imbalances have been reported in the English-language medical literature to date but mostly with the use of TMP in combination with sulfamethoxazole. In association with TMP use, hyperkalaemia has been more commonly reported than hyponatraemia. These changes in sodium and potassium balance are thought to be related to TMP inhibiting sodium ion influx via the epithelial sodium channel in the cortical collecting duct. The association between symptomatic hyponatraemia and TMP emphasizes the need to evaluate electrolytes in patients presenting with clinical change after commencing on this drug.

Effect of blade-surface-roughness on the pumping performance of a turbomolecular pump

NASA Astrophysics Data System (ADS)

Sawada, T.; Yabuki, M.; Sugiyama, W.; Watanabe, M.

2005-11-01

Turbomolecular pumps (TMPs) are widely used in the semiconductor and other thin film industries. Some semiconductor processes form corrosive gases such as HCl or HF as byproducts. The elements of a TMP are sometimes coated with ceramic (SiO2) film for the purpose of preventing corrosion of the TMP. The blades coated with SiO2 have relatively rough surfaces. The effect of the surface roughness of the blades on the pumping performance has been studied experimentally and theoretically. Experimental results for TMPs with two rotor disks and one stator disk show that the TMP coated with SiO2 film gives about 11% to 13% higher maximum-compression ratio than the noncoated TMP when the blade speed ratio is 0.47. The theory based on the conic peak/dimple-surface-roughness model that has been proposed by the authors explains the change in the compression ratio with the surface roughness shown in the experiment.

Oxidation of trimethoprim by ferrate(VI): kinetics, products, and antibacterial activity.

PubMed

Anquandah, George A K; Sharma, Virender K; Knight, D Andrew; Batchu, Sudha Rani; Gardinali, Piero R

2011-12-15

Kinetics, stoichiometry, and products of the oxidation of trimethoprim (TMP), one of the most commonly detected antibacterial agents in surface waters and municipal wastewaters, by ferrate(VI) (Fe(VI)) were determined. The pH dependent second-order rate constants of the reactions of Fe(VI) with TMP were examined using acid-base properties of Fe(VI) and TMP. The kinetics of reactions of diaminopyrimidine (DAP) and trimethoxytoluene (TMT) with Fe(VI) were also determined to understand the reactivity of Fe(VI) with TMP. Oxidation products of the reactions of Fe(VI) with TMP and DAP were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Reaction pathways of oxidation of TMP by Fe(VI) are proposed to demonstrate the cleavage of the TMP molecule to ultimately result in 3,4,5,-trimethoxybenzaldehyde and 2,4-dinitropyrimidine as among the final identified products. The oxidized products mixture exhibited no antibacterial activity against E. coli after complete consumption of TMP. Removal of TMP in the secondary effluent by Fe(VI) was achieved.

The membrane separation mechanism in protein concentration from the extract of waste press cake in biofuel manufacturing process of Jatropha seeds

NASA Astrophysics Data System (ADS)

Chung, T. W.; Chen, C. K.; Hsu, S. H.

2017-11-01

Protein concentration process using filter membrane has a significant advantage on energy saving compared to the traditional drying processes. However, fouling on large membrane area and frequent membrane cleaning will increase the energy consumption and operation cost for the protein concentration process with filter membrane. In this study, the membrane filtration for protein concentration will be conducted and compared with the recent protein concentration technology. The analysis of operating factors for protein concentration process using filter membrane was discussed. The separation mechanism of membrane filtration was developed according to the size difference between the pore of membrane and the particle of filter material. The Darcy’s Law was applied to discuss the interaction on flux, TMP (transmembrane pressure) and resistance in this study. The effect of membrane pore size, pH value and TMP on the steady-state flux (Jst) and protein rejection (R) were studied. It is observed that the Jst increases with decreasing membrane pore size, the Jst increases with increasing TMP, and R increased with decreasing solution pH value. Compare to other variables, the pH value is the most significant variable for separation between protein and water.

Urinary biomarkers of trimethoprim bioactivation in vivo following therapeutic dosing in children.

PubMed

van Haandel, Leon; Goldman, Jennifer L; Pearce, Robin E; Leeder, J Steven

2014-02-17

The antimicrobial trimethoprim-sulfamethoxazole (TMP-SMX) is widely used for the treatment of skin and soft-tissue infections in the outpatient setting. Despite its therapeutic benefits, TMP-SMX has been associated with a number of adverse drug reactions, which have been primarily attributed to the formation of reactive metabolites from SMX. Recently, in vitro experiments have demonstrated that TMP may form reactive intermediates as well. However, evidence of TMP bioactivation in patients has not yet been demonstrated. In this study, we performed in vitro trapping experiments with N-acetyl-l-cysteine (NAC) to determine stable markers of reactive TMP intermediates, focusing on eight potential markers (NAC-TMP adducts), some of which were previously identified in vitro. We developed a specific and sensitive assay involving liquid chromatography followed by tandem mass spectrometry for measurement of these adducts in human liver microsomal samples and expanded the methodology toward the detection of these analytes in human urine. Urine samples from four patients receiving TMP-SMX treatment were analyzed, and all samples demonstrated the presence of six NAC-TMP adducts, which were also detected in vitro. These adducts are consistent with the formation of imino-quinone-methide and para-quinone-methide reactive intermediates in vivo. As a result, the TMP component of TMP-SMX should be considered as well when evaluating adverse drug reactions to TMP-SMX.

EFFECT OF TRIMETHOPRIM-SULFAMETHOXAZOLE PROPHYLAXIS ON FAECAL CARRIAGE RATES OF RESISTANT ISOLATES OF ESCHERICHIA COLI IN HIV-INFECTED ADULT PATIENTS IN LAGOS.

PubMed

Egwuatu, C C; Iwuafor, A A; Egwuatu, T O; Akujobi, C N; Nnachi, A U; Aghanya, I N; Ogunsola, F T; Oduyebo, O O

2016-01-01

The daily use of Trimethoprim-Sulfamethoxazole (TMP-SMX) prophylaxis reduces morbidity and mortality among patients infected with Human Immunodeficiency Virus (HIV) but its impact on increasing antimicrobial resistance rates has been of public concern globally. This study investigated the effect of daily TMP-SMX prophylaxis on faecal carriage rates of resistant isolates of Escherichia coli in HIV-infected adult patients in Lagos. A total of 550 HIV-infected patients with CD4-cell count of less than 350 cell/mm 3 and were eligible for TMP-SMX prophylaxis attending Lagos University Teaching Hospital, Lagos, Nigeria, were recruited. Stool/rectal swab samples were aseptically collected from the patients and processed using standard methods for culture and sensitivity. There was a baseline Trimethoprim-Sulfamethoxazole resistance rate of 54% which increased to 77.9% in first 3 months, rising to 96.1% by 6 months and all isolates were resistant by the 9th month. There was also evidence of cross-resistance to other antibiotics with significant association with TMP-SMX resistance (p<0.0001). The Escherichia coli isolates showed a progressive increase in resistance to the tested antibiotics over the 12-month period. The resistance was in the following order: Ampicillin (74% to 82.6% in the first 3 months; 98.3% by the 6th month and 99.4% by the 9th month; all isolates were resistant by the 12th month). Augmentin (32.5% to 47.7% in first 3 months; 76.1% by the 6th month; 86.3% by the 9th month; all isolates were resistant by 12 months). Ceftriaxone (2.0% to 10.8% in first 3 months; 20.6% by the 6th month; 24.2% by the 9th month; 54.3% by the 12 months). The carriage rate of faecal E. coli resistant to TMP-SMX is common before TMP-SMX prophylaxis. Initiation of TMP-SMX leads to further increase in resistance to TMP-SMX and cross-resistance to other antimicrobials.

UV/H2O2 and UV/PDS Treatment of Trimethoprim and Sulfamethoxazole in Synthetic Human Urine: Transformation Products and Toxicity.

PubMed

Zhang, Ruochun; Yang, Yongkui; Huang, Ching-Hua; Li, Na; Liu, Hang; Zhao, Lin; Sun, Peizhe

2016-03-01

Elimination of pharmaceuticals in source-separated human urine is a promising approach to minimize the pharmaceuticals in the environment. Although the degradation kinetics of pharmaceuticals by UV/H2O2 and UV/peroxydisulfate (PDS) processes has been investigated in synthetic fresh and hydrolyzed urine, comprehensive evaluation of the advanced oxidation processes (AOPs), such as product identification and toxicity testing, has not yet been performed. This study identified the transformation products of two commonly used antibiotics, trimethoprim (TMP) and sulfamethoxazole (SMX), by UV/H2O2 and UV/PDS in synthetic urine matrices. The effects of reactive species, including •OH, SO4(•-), CO3(•-), and reactive nitrogen species, on product generation were investigated. Multiple isomeric transformation products of TMP and SMX were observed, especially in the reaction with hydroxyl radical. SO4(•-) and CO3(•-) reacted with pharmaceuticals by electron transfer, thus producing similar major products. The main reactive species deduced on the basis of product generation are in good agreement with kinetic simulation of the advanced oxidation processes. A strain identified as a polyphosphate-accumulating organism was used to investigate the antimicrobial activity of the pharmaceuticals and their products. No antimicrobial property was detected for the transformation products of either TMP or SMX. Acute toxicity employing luminescent bacterium Vibrio qinghaiensis indicated 20-40% higher inhibitory effect of TMP and SMX after treatment. Ecotoxicity was estimated by quantitative structure-activity relationship analysis using ECOSAR.

Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIβ pathway.

PubMed

Yan, Yong-Xin; Zhao, Jun-Xia; Han, Shuo; Zhou, Na-Jing; Jia, Zhi-Qiang; Yao, Sheng-Jie; Cao, Cui-Li; Wang, Yan-Ling; Xu, Yan-Nan; Zhao, Juan; Yan, Yun-Li; Cui, Hui-Xian

2015-12-01

Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIβ (TopoIIβ), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIβ expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80μM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin βIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIβ, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIβ gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIβ expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIβ signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIβ in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system. Copyright © 2015 Elsevier GmbH. All rights reserved.

A rapid and fluorogenic TMP-AcBOPDIPY probe for covalent labeling of proteins in live cells.

PubMed

Liu, Wei; Li, Fu; Chen, Xi; Hou, Jian; Yi, Long; Wu, Yao-Wen

2014-03-26

Protein labeling is enormously useful for characterizing protein function in cells and organisms. Chemical tagging methods have emerged as a new generation protein labeling strategy in live cells. Here we have developed a novel and versatile TMP-AcBOPDIPY probe for selective and turn-on labeling of proteins in live cells. A small monomeric tag, E. coli dihydrofolate reductase (eDHFR), was rationally designed to introduce a cysteine in the vicinity of the ligand binding site. Trimethoprim (TMP) that specifically binds to eDHFR was linked to the BOPDIPY fluorophore containing a mildly thiol-reactive acrylamide group. TMP-AcBOPDIPY rapidly labeled engineered eDHFR tags via a reaction termed affinity conjugation (a half-life of ca. 2 min), which is one of the top fast chemical probes for protein labeling. The probe displays 2-fold fluorescence enhancement upon labeling of proteins. We showed that the probe specifically labeled intracellular proteins in live cells without and with washing out the dye. We demonstrated its utility in visualizing intracellular processes by fluorescence-lifetime imaging microscopy (FLIM) measurements.

Successful outpatient graded administration of trimethoprim-sulfamethoxazole in patients without HIV and with a history of sulfonamide adverse drug reaction.

PubMed

Pyle, Regan C; Butterfield, Joseph H; Volcheck, Gerald W; Podjasek, Jenna C; Rank, Matthew A; Li, James T C; Harish, Amitha; Poe, Kimberly L; Park, Miguel A

2014-01-01

The outcomes of trimethoprim-sulfamethoxazole (TMP-SMX) desensitization have been widely reported in the HIV literature but less so in the non-HIV literature. To evaluate the safety and efficacy of graded administration of TMP-SMX in patients without HIV and with a history of TMP-SMX adverse drug reaction (ADR). A retrospective chart review, 2004-2012, of all the patients without HIV seen in the Division of Allergic Diseases and with a history of TMP-SMX ADR who underwent outpatient graded administration of TMP-SMX was conducted. The medical record was reviewed for age, sex, details of the initial ADR to TMP-SMX, an indication for TMP-SMX administration, and outcome. Patients also were contacted by telephone, and medical records were reviewed to determine long-term outcomes. Seventy-two patients (46 women [64%]; mean [SD] age, 57.7 ± 13.89 years]) were included. The most common patient-reported reactions to TMP-SMX were rash 39 (54%), and hives 9 (13%). TMP-SMX administration was needed for the following indications: prophylaxis (62 [86%]) and treatment of infection (10 [14%]). Forty-three of the patients (60%) underwent a 1-day TMP-SMX administration protocol. Thirty-five of the 43 (81%) underwent a 6-step (90 minutes to 6 hours) protocol and 7 of the 43 (16%) underwent a novel 14-step TMP-SMX protocol. Twenty-nine (40%) underwent a >1-day TMP-SMX administration protocol. Our overall success rate was 90% (mean duration of 11 months). Ninety-eight percent of the patients successfully completed a 1-day graded administration protocol, and 76% successfully completed a >1-day protocol. TMP-SMX was stopped in 8 patients because of the ADR. We report the largest case series of successful outpatient graded administration of TMP-SMX with both 1-day and >1-day protocols, which have shown to be safe and well tolerated in patients without HIV and with a history of sulfonamide ADR. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Inventory of File SN.2012091412.grib.f18.grib2

Science.gov Websites

of Wind [m/s] 004 surface TMP 18 hour fcst Temperature [K] 005.1 50 mb UGRD 18 hour fcst U-Component 18 hour fcst Temperature [K] 026 100 mb TMP 18 hour fcst Temperature [K] 027 150 mb TMP 18 hour fcst Temperature [K] 028 200 mb TMP 18 hour fcst Temperature [K] 029 250 mb TMP 18 hour fcst Temperature [K] 030

A simple model for metal cation-phosphate interactions in nucleic acids in the gas phase: alkali metal cations and trimethyl phosphate.

PubMed

Ruan, Chunhai; Huang, Hai; Rodgers, M T

2008-02-01

Threshold collision-induced dissociation techniques are employed to determine the bond dissociation energies (BDEs) of complexes of alkali metal cations to trimethyl phosphate, TMP. Endothermic loss of the intact TMP ligand is the only dissociation pathway observed for all complexes. Theoretical calculations at the B3LYP/6-31G* level of theory are used to determine the structures, vibrational frequencies, and rotational constants of neutral TMP and the M+(TMP) complexes. Theoretical BDEs are determined from single point energy calculations at the B3LYP/6-311+G(2d,2p) level using the B3LYP/6-31G* optimized geometries. The agreement between theory and experiment is reasonably good for all complexes except Li+(TMP). The absolute M+-(TMP) BDEs are found to decrease monotonically as the size of the alkali metal cation increases. No activated dissociation was observed for alkali metal cation binding to TMP. The binding of alkali metal cations to TMP is compared with that to acetone and methanol.

Effect of trimetaphosphate and fluoride association on hydroxyapatite dissolution and precipitation in vitro.

PubMed

Delbem, Alberto Carlos Botazzo; Souza, José Antonio Santos; Zaze, Ana Carolina Soares Fraga; Takeshita, Eliana Mitsue; Sassaki, Kikue Takebayashi; Moraes, João Carlos Silos

2014-01-01

The present study analyzed the action of sodium trimetaphosphate (TMP) and/or fluoride on hydroxyapatite. Hydroxyapatite powder was suspended in different solutions: deionized water, 500 µg F/mL, 1,100 µg F/mL, 1%TMP, 3%TMP, 500 µg F/mL plus 1%TMP and 500 µg F/mL plus 3%TMP. The pH value of the solutions was reduced to 4.0 and after 30 min, raised to 7.0 (three times). After pH-cycling, the samples were analyzed by X-ray diffraction and infrared spectroscopy. The concentrations of calcium fluoride, fluoride, calcium and phosphorus were also determined. Adding 1% or 3% TMP to the solution containing 500 µg F/mL produced a higher quantity of calcium fluoride compared to samples prepared in a 1,100 µg F/mL solution. Regarding the calcium concentration, samples prepared in solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP were statistically similar and showed higher values. Using solutions of 1,100 µg F/mL and 500 µg F/mL plus TMP resulted in a calcium/phosphorus ratio close to that of hydroxyapatite. It is concluded that the association of TMP and fluoride favored the precipitation of a more stable hydroxyapatite.

In vitro effect of sodium trimetaphosphate additives to conventional toothpastes on enamel demineralization.

PubMed

de Castro, Luciene Pereira; Delbem, Alberto Carlos Botazzo; Danelon, Marcelle; Passarinho, Amanda; Percinoto, Célio

2015-09-01

The aim of this study was to evaluate the ability of conventional toothpastes (1100 ppm F) supplemented with sodium trimetaphosphate (TMP) in demineralization. Blocks of enamel were selected and then divided into seven experimental groups of 12: toothpaste without F and TMP (placebo), toothpaste with 1100 ppm F (1100), and toothpaste with 1100 ppm F supplemented with TMP-1 % (1100 1 % TMP), 3 % (1100 3 % TMP), 4.5 % (1100 4.5 % TMP), 6 % (1100 6 % TMP), and 9 % (1100 9 % TMP). Blocks were subjected to five pH cycles (demineralizing/remineralizing solutions) at 37 °C and treated with toothpaste slurries twice daily, after which the blocks were maintained for 2 days in fresh remineralizing solution. Following treatments, surface hardness (SHf) and cross-sectional hardness were determined for calculating the integrated loss of subsurface hardness (ΔKHN). The fluoride present in the enamel was also measured. The SHf and ΔKHN measurements showed that supplementation with 3 % TMP was the most effective (p < 0.001) and showed greater concentration of F in the enamel (p < 0.001). Addition of 3 % TMP to a conventional toothpaste (1100 ppm F) showed greater efficacy in reducing enamel demineralization. Fluoride toothpastes containing trimetaphosphate possess good anticaries potential required to reduce the prevalence of dental caries in high-risk patients.

Heart Mitochondrial TTP Synthesis and the Compartmentalization of TMP*

PubMed Central

Kamath, Vasudeva G.; Hsiung, Chia-Heng; Lizenby, Zachary J.; McKee, Edward E.

2015-01-01

The primary pathway of TTP synthesis in the heart requires thymidine salvage by mitochondrial thymidine kinase 2 (TK2). However, the compartmentalization of this pathway and the transport of thymidine nucleotides are not well understood. We investigated the metabolism of [3H]thymidine or [3H]TMP as precursors of [3H]TTP in isolated intact or broken mitochondria from the rat heart. The results demonstrated that [3H]thymidine was readily metabolized by the mitochondrial salvage enzymes to TTP in intact mitochondria. The equivalent addition of [3H]TMP produced far less [3H]TTP than the amount observed with [3H]thymidine as the precursor. Using zidovudine to inhibit TK2, the synthesis of [3H]TTP from [3H]TMP was effectively blocked, demonstrating that synthesis of [3H]TTP from [3H]TMP arose solely from the dephosphorysynthase pathway that includes deoxyuridine triphosphatelation of [3H]TMP to [3H]thymidine. To determine the role of the membrane in TMP metabolism, mitochondrial membranes were disrupted by freezing and thawing. In broken mitochondria, [3H]thymidine was readily converted to [3H]TMP, but further phosphorylation was prevented even though the energy charge was well maintained by addition of oligomycin A, phosphocreatine, and creatine phosphokinase. The failure to synthesize TTP in broken mitochondria was not related to a loss of membrane potential or inhibition of the electron transport chain, as confirmed by addition of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone and potassium cyanide, respectively, in intact mitochondria. In summary, these data, taken together, suggest that the thymidine salvage pathway is compartmentalized so that TMP kinase prefers TMP synthesized by TK2 over medium TMP and that this is disrupted in broken mitochondria. PMID:25505243

Rational and efficient preparation of a chimeric protein containing a tandem dimer of thrombopoietin mimetic peptide fused to human growth hormone in Escherichia coli.

PubMed

Wang, Song; Shen, Mingqiang; Xu, Yang; Chen, Fang; Chen, Mo; Chen, Shilei; Wang, Aiping; Zhang, Zhou; Ran, Xinze; Cheng, Tianmin; Su, Yongping; Wang, Junping

2013-04-01

The 14-mer thrombopoietin mimetic peptide (TMP), especially in the form of dimer, displayed potent megakaryocytopoiesis activity in vitro. However, it is difficult to prepare such short peptide with high bioactivity through gene-engineering approaches. In this study, a chimeric protein containing a tandem dimer of TMP (dTMP) fused to human growth hormone (hGH), a kind of hematopoietic growth factor that activates the same signal pathways as thrombopoietin, was produced in Escherichia coli by soluble expression. By rational utilization of the XmnI and EcoRV restriction sites, a PCR fragment encoding dTMP-GH was inserted into the plasmid vector pMAL-p2X at the position right after Xa factor cleavage site, in frame with maltose-binding protein (MBP) gene. Under optimized conditions, a high-level expression of soluble MBP-dTMP-GH fusion protein was obtained. By application of amylose resin chromatography, Xa factor digestion, hydrophobic chromatography followed by gel filtration, the dTMP-GH fusion protein was separated. Finally, a relatively high yield of dTMP-GH fusion protein with high purity (>98%) and without redundant amino acid was achieved, as identified by high-performance liquid chromatography, mass spectrometry, and amino acid sequencing. The functional assays showed that dTMP-GH could promote the proliferation of megakaryoblast cells and maturation of murine megakaryocytes derived from bone marrow, in a dose-dependent manner. Moreover, an enhanced effect of dTMP-GH on megakaryocytopoiesis was found as compared with equimolar concentration of dTMP and rhGH. This work provides a new avenue to generate thrombopoietic agents based on TMP.

Risk Factors for Trimethoprim-Sulfamethoxazole Resistance in Patients with Acute Uncomplicated Cystitis▿

PubMed Central

Colgan, Richard; Johnson, James R.; Kuskowski, Michael; Gupta, Kalpana

2008-01-01

Emerging antimicrobial resistance among uropathogens makes the management of acute uncomplicated cystitis increasingly challenging. Few prospective data are available on the risk factors for resistance to trimethoprim-sulfamethoxazole (TMP-SMX), the drug of choice in most settings. In order to evaluate this, we prospectively enrolled women 18 to 50 years of age presenting to an urban primary care practice with symptoms of cystitis. Potentially eligible women provided a urine sample for culture and completed a questionnaire regarding putative risk factors for TMP-SMX resistance. Escherichia coli isolates were tested for clonal group A (CGA) membership by a fumC-specific PCR. Of 165 women with cystitis symptoms, 103 had a positive urine culture and were eligible for participation. E. coli was the predominant uropathogen (86%). Fifteen (14.6%) women had a TMP-SMX-resistant (TMP-SMXr) organism (all of which were E. coli). Compared with the women who had a TMP-SMX-susceptible organism, women in the TMP-SMXr group were more likely to have traveled (odds ratio [OR], 15.4; 95% confidence interval [CI], 4.4 to 54.3; P < 0.001) and to be Asian (OR, 6.1; 95% CI, 1.0 to 36.4; P = 0.048). CGA was also independently associated with TMP-SMX resistance (OR, 105; 95% CI, 6.3 to 1,777.6; P = 0.001). No association with TMP-SMX resistance was demonstrated for the use of either TMP-SMX or another antibiotic in the past 3 months or with having a child in day care. Among these women with acute uncomplicated cystitis, Asian race and recent travel were independently associated with TMP-SMX resistance. TMP-SMXr isolates were more likely to belong to CGA. Knowledge of these risk factors for TMP-SMX resistance could facilitate the accurate selection of empirical therapy. PMID:18086847

Autohydrolysis Pretreatment of Lignocellulosic Biomass for Bioethanol Production

NASA Astrophysics Data System (ADS)

Han, Qiang

Autohydrolysis, a simple and environmental friendly process, has long been studied but often abandoned as a financially viable pretreatment for bioethanol production due to the low yields of fermentable sugars at economic enzyme dosages. The introduction of mechanical refining can generate substantial improvements for autohydrolysis process, making it an attractive pretreatment technology for bioethanol commercialization. In this study, several lignocellulosic biomass including wheat straw, switchgrass, corn stover, waste wheat straw have been subjected to autohydrolysis pretreatment followed by mechanical refining to evaluate the total sugar recovery at affordable enzyme dosages. Encouraging results have been found that using autohydrolysis plus refining strategy, the total sugar recovery of most feedstock can be as high as 76% at 4 FPU/g enzymes dosages. The mechanical refining contributed to the improvement of enzymatic sugar yield by as much as 30%. Three non-woody biomass (sugarcane bagasse, wheat straw, and switchgrass) and three woody biomass (maple, sweet gum, and nitens) have been subjected to autohydrolysis pretreatment to acquire a fundamental understanding of biomass characteristics that affect the autohydrolysis and the following enzymatic hydrolysis. It is of interest to note that the nonwoody biomass went through substantial delignification during autohydrolysis compared to woody biomass due to a significant amount of p-coumaric acid and ferulic acid. It has been found that hardwood which has a higher S/V ratio in the lignin structure tends to have a higher total sugar recovery from autohydrolysis pretreatment. The economics of bioethanol production from autohydrolysis of different feedstocks have been investigated. Regardless of different feedstocks, in the conventional design, producing bioethanol and co-producing steam and power, the minimum ethanol revenues (MER) required to generate a 12% internal rate of return (IRR) are high enough to discourage investors due to the high capital investment relative to low US ethanol price. Nevertheless, the economics of autohydrolysis can be substantially improved by upgrading the value of unhydrolyzed residues, such as the fuel pellets. Moreover, the utilization of proven technology and equipment renders autohydrolysis adaptable to pulp and paper industrial. Attractive economics have been found when autohydrolysis based bioethanol plant is co-located to a pulp and paper mill or the distressed pulp and paper mill is being repurposed to produce bioethanol. An alternative to autohydrolysis combined with refining, thermomechanical pulping (TMP) process has been evaluated using corn stover as the feedstock. A significant low solids yield after the pretreatment process has been observed due to the harsh condition operated and the limitation of lab equipment. But the TMP process has great potential to be employed as a pretreatment for bioethanol production in an industrial scale if the process is optimized.

Synthesis of TMP-ester biolubricant basestock from palm stearin fatty acids

NASA Astrophysics Data System (ADS)

Fadzel, Fatimatuzzahraa Mohd; Salimon, Jumat; Derawi, Darfizzi

2018-04-01

A potential biolubricant; TMP-ester was produced via esterification of fatty acids (FA) from palm stearin (PS) with trimethylolpropane (TMP). The synthesis was conducted at four conditions; temperature, time, molar ratio of FA:TMP and H2SO4 as catalyst (by percent based on the weight of FA and TMP) that are 150 °C, 2 hours, 4:1 and 1% of H2SO4 respectively. The composition of ester produced was determined using gas chromatography (GC-FID). The presence of ester group was confirmed by the means of FTIR by the existence of strong carboxyl band of ester, v(C=O) at 1746cm-1 and 1H and 13C NMR spectroscopy shows the chemical shift, δ of ester, C=O at 2.27-2.31 ppm and 173.45 ppm accordingly. From the esterification reaction, 95% product of TMP-ester was formed. The thermal and oxidative stability of TMP-ester is 200°C.

Synthesis and physicochemical properties of epoxidized Tmp trioleate by in situ method

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

Samidin, Salma; Salimon, Jumat

2014-09-03

Tmp trioleate was initially synthesized via esterification of trimetilolprapane and oleic acid (90%) using 1.5% of H{sub 2}SO{sub 4} as a catalyst. The production of Tmp trioleate was observed at 98% (w/w). The iodine value of Tmp trioleate was analyzed for further reaction of epoxidation. Epoxide was important reaction as an intermediate for preparation of chemical modified lubricants from vegetable oils. Finding the best way of epoxidation process will give high quality for further modification of oil instead of reduce the cost and time for the preparation process during reaction of epoxidation. In this study, the epoxidation of unsaturation Tmpmore » trioleate with peroxyformic acid generated in-situ from hydrogen peroxide 30% in H{sub 2}O{sub 2} with formic acid was studied. 95% conversion to oxygen oxirane content (OOC) ring was obtained. The derivatization showed an improvement of the compound's oxidative stability evidenced from pressurized differential scanning calorimetry (PDSC) data which are 177°C to 200°C. Physicochemical properties showed increasing of temperature of flash point from 280°C to 300°C and viscosity index (VI) from 146 to 154. However, the pour point showed increasing temperature which was −58.81°C to −17.32°C. From the data obtained, these derivatives have shown better performance of lubricity properties. Overall, the data indicates that these performances are compatible to the commercial lubricants.« less

Effects of trimethoprim on life history parameters, oxidative stress, and the expression of cytochrome P450 genes in the copepod Tigriopus japonicus.

PubMed

Han, Jeonghoon; Lee, Min-Chul; Kim, Duck-Hyun; Lee, Young Hwan; Park, Jun Chul; Lee, Jae-Seong

2016-09-01

Trimethoprim (TMP) is an antibiotic that has been detected in various environments including marine habitats; however, the toxic effects of TMP are poorly understood in non-target marine organisms. In this study, the effects of TMP on mortality, development, reproduction, intracellular reactive oxygen species (ROS) levels, and transcription levels of antioxidant and xenobiotic detoxification-related enzyme genes were investigated in the copepod Tigriopus japonicus. The TMP half lethal dose at 48 h (LC50-48 h) in nauplius and TMP LC50-96 h in adult T. japonicus copepods was determined as 156 mg/L and 200 mg/L, respectively. In TMP-exposed T. japonicus, delayed developmental time and impaired reproduction were observed as harmful effects on the life history parameters. Increased ROS levels were also shown in response to TMP exposure at the highest concentration (100 mg/L TMP) and the expression of antioxidant- (e.g. GST-kappa, GST-sigma) and xenobiotic detoxification (e.g. CYPs)-related genes were upregulated in a time and/or dose-dependent manner in response to TMP. Particularly, significant upregulation of three CYP genes (Tj-CYP3024A2, Tj-CYP3024A3 and Tj-CYP3027C2) were examined, suggesting that these CYP genes are likely playing an important role in the TMP detoxification metabolism in T. japonicus. In summary, we found that TMP induced oxidative stress via the transcriptional regulation of antioxidant- and xenobiotic detoxification-related genes, leading to changes in life history parameters such as developmental delay and reproduction impairment. Three Tj-CYP genes (Tj-CYP3024A2, Tj-CYP3024A3 and Tj-CYP3027C2) could be useful as potential T. japonicus biomarkers in response to antibiotics. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Fluorogenic TMP-tag for High Signal-to-Background Intracellular Live Cell Imaging

PubMed Central

Jing, Chaoran

2013-01-01

Developed to compliment the use of fluorescent proteins in live cell imaging, chemical tags enjoy the benefit of modular incorporation of organic fluorophores, opening the possibility of high photon output and special photophysical properties. However, the theoretical challenge in using chemical tags as opposed to fluorescent proteins for high-resolution imaging is background noise from unbound and/or non-specifically bound ligand-fluorophore. We envisioned we could overcome this limit by engineering fluorogenic trimethoprim-based chemical tags (TMP-tags) in which the fluorophore is quenched until binding with E. coli dihydrofolate reductase (eDHFR) tagged protein displaces the quencher. Thus, we began by building a non-fluorogenic, covalent TMP-tag based on a proximity-induced reaction known to achieve rapid and specific labeling both in vitro and inside of living cells. Here we take the final step and render the covalent TMP-tag fluorogenic. In brief, we designed a trimeric TMP-fluorophore-quencher molecule (TMP-Q-Atto520) with the quencher attached to a leaving group that, upon TMP binding to eDHFR, would be cleaved by a cysteine residue (Cys) installed just outside the binding pocket of eDHFR. We present the in vitro experiments showing that the eDHFR:L28C nucleophile cleaves the TMP-Q-Atto520 rapidly and efficiently, resulting in covalent labeling and remarkable fluorescence enhancement. Most significantly, while only our initial design, TMP-Q-Atto520 achieved the demanding goal of not only labeling highly abundant, localized intracellular proteins, but also less abundant, more dynamic cytoplasmic proteins. These results suggest that fluorogenic TMP-tag can significantly impact highresolution live cell imaging and further establish the potential of proximity-induced reactivity and organic chemistry more broadly as part of the growing toolbox for synthetic biology and cell engineering. PMID:23745575

Treatment of Pneumocystis pneumonia with intermediate-dose and step-down to low-dose trimethoprim-sulfamethoxazole: lessons from an observational cohort study.

PubMed

Creemers-Schild, Dina; Kroon, Frank P; Kuijper, Ed J; de Boer, Mark G J

2016-06-01

The recommended treatment of Pneumocystis jirovecii pneumonia (PCP) is high-dose trimethoprim-sulfamethoxazole (TMP-SMX) in an equivalent of TMP 15-20 mg/kg/day and SMX 75-100 mg/kg/day for 2 or 3 weeks. High rates of adverse events are reported with this dose, which raises the question if lower doses are possible. All adult patients diagnosed with PCP in various immune dysfunctions and treated with TMP-SMX between January 1, 2003 and July 1, 2013 in a tertiary university hospital were included. Per institutional protocol, patients initiated treatment on intermediate-dose TMP-SMX (TMP 10-15 mg/kg/day) and could be stepped down to low-dose TMP-SMX (TMP 4-6 mg/kg/day) during treatment. Clinical variables at presentation, relapse rate and mortality rates were compared between intermediate- and step-down treatment groups by uni- and multivariate analyses. A total of 104 patients were included. Twenty-four patients (23 %) were switched to low-dose TMP-SMX after a median of 4.5 days (IQR 2.8-7.0 days). One relapse (4 %) occurred in the step-down group versus none in the intermediate-dose group. The overall 30-day mortality was 13 %. There was 1 death in the step-down group (4 %) compared to 13 deaths (16 %) in the intermediate-dose group. We observed high cure rates of PCP by treatment with intermediate-dose TMP-SMX. In addition, a step-down strategy to low-dose TMP-SMX during treatment in selected patients appears to be safe and does not compromise the outcome of treatment.

Power Efficient Hardware Architecture of SHA-1 Algorithm for Trusted Mobile Computing

NASA Astrophysics Data System (ADS)

Kim, Mooseop; Ryou, Jaecheol

The Trusted Mobile Platform (TMP) is developed and promoted by the Trusted Computing Group (TCG), which is an industry standard body to enhance the security of the mobile computing environment. The built-in SHA-1 engine in TMP is one of the most important circuit blocks and contributes the performance of the whole platform because it is used as key primitives supporting platform integrity and command authentication. Mobile platforms have very stringent limitations with respect to available power, physical circuit area, and cost. Therefore special architecture and design methods for low power SHA-1 circuit are required. In this paper, we present a novel and efficient hardware architecture of low power SHA-1 design for TMP. Our low power SHA-1 hardware can compute 512-bit data block using less than 7,000 gates and has a power consumption about 1.1 mA on a 0.25μm CMOS process.

New insights into membrane fouling in submerged MBR under sub-critical flux condition.

PubMed

Li, Jianfeng; Zhang, Xiuxiu; Cheng, Fangqin; Liu, Yu

2013-06-01

This study investigated the membrane fouling in MBRs under sub-critical flux condition. Results showed membrane fouling at subcritical flux evolved through a three-stage process: a slow linear increase in transmembrane pressure (TMP) (stage I), followed by an exponential increase in TMP (stage II), and finally a rapid linear TMP rise was observed at stage III. It was found that bound EPS would play a significant role in fouling development at stage I, while SMPs appeared to be the major contributor to self-accelerating fouling phenomena observed at stage II. At stage III, the entire membrane was covered by a cake layer of flocs, as the result, the fouling rate was likely determined by floc characteristics. This study offers new insights into the fouling development under sub-critical flux condition. Copyright © 2013 Elsevier Ltd. All rights reserved.

Atovaquone for Prophylaxis of Toxoplasmosis after Allogeneic Hematopoietic Stem Cell Transplantation.

PubMed

Mendorf, Alexander; Klyuchnikov, Evgeny; Langebrake, Claudia; Rohde, Holger; Ayuk, Francis; Regier, Marc; Christopeit, Maximilian; Zabelina, Tatjana; Bacher, Adelbert; Stübig, Thomas; Wolschke, Christine; Bacher, Ulrike; Kröger, Nicolaus

2015-01-01

Toxoplasmosis and infections by other opportunistic agents such as Pneumocystis jirovecii constitute life-threatening risks for patients after allogeneic hematopoietic stem cell transplantation. Trimethoprim/sulfamethoxazole (TMP-SMX) has been well established for post-transplant toxoplasmosis and pneumocystis prophylaxis, but treatment may be limited due to toxicity. We explored atovaquone as an alternative and compared it with TMP-SMX regarding toxicity and efficacy during the first 100 days after transplantation in 155 consecutive adult stem cell recipients. Eight patients with a prior history of TMP-SMX intolerance received atovaquone as first-line prophylaxis. TMP-SMX was used for 141 patients as first-line strategy, but 13 patients (9.2%) were later switched to atovaquone due to TMP-SMX toxicity or gastrointestinal symptoms. No active toxoplasmosis or active P. jirovecii infection developed under continued prophylaxis with either TMP-SMX or atovaquone. However, for reasons of TMP-SMX and/or atovaquone toxicity, 7 patients were unable to tolerate any efficacious toxoplasmosis prophylaxis and therefore obtained inhalative pentamidine as P. jirovecii prophylaxis but no toxoplasmosis prophylaxis. Importantly, 2 of these patients developed severe toxoplasmosis. In summary, atovaquone appears as a valid alternative for at least some post-transplant patients who cannot tolerate TMP-SMX. This should be further confirmed by multicenter trials. © 2015 S. Karger AG, Basel.

Efficacy of trimethoprim/sulfamethoxazole in experimental Escherichia coli bacteremia and meningitis.

PubMed

Kim, K S; Anthony, B F

1983-01-01

We evaluated the activity of trimethoprim/sulfamethoxazole (TMP/SMZ) against a K1 Escherichia coli strain. Minimal inhibitory and bactericidal concentrations were 0.06/1.14 and 0.25/4.75 micrograms/ml, respectively. In vivo studies using an infant rat model of bacteremia and meningitis revealed that TMP/SMZ penetrated well into the cerebrospinal fluid (CSF) and that 37% of serum levels were achieved. The efficacy of TMP/SMZ was compared with that of ampicillin, chloramphenicol, cefotaxime and lamoxactam. Bacterial clearance from blood and CSF was significantly greater with TMP/SMZ than with ampicillin or chloramphenicol and mortality was significantly less than with chloramphenicol (p less than 0.01). However, 3 of 21 (14%) and 2 of 8 animals (25%) still had positive blood and CSF cultures after 3 days of treatment with TMP/SMZ. None of the survivors in the cefotaxime and lamoxactam groups were bacteremic after 1 day of therapy. Furthermore, 5 of 13 animals (38%) treated with TMP/SMZ developed meningitis during therapy, in contrast with none in the cefotaxime and lamoxactam groups. These findings indicate that although the activity of TMP/SMZ is bactericidal in vitro and in vivo against E. coli, TMP/SMZ may not provide optimal therapy for gram-negative bacillary meningitis in this model.

Inventory of File naefs_ge90pt.t12z.pgrb2a_bcf06

Science.gov Websites

hour fcst Temperature [K] unknown derived fcst 012 925 mb TMP 6 hour fcst Temperature [K] unknown derived fcst 013 850 mb TMP 6 hour fcst Temperature [K] unknown derived fcst 014 700 mb TMP 6 hour fcst Temperature [K] unknown derived fcst 015 500 mb TMP 6 hour fcst Temperature [K] unknown derived fcst 016 250

Sorption-desorption and transport of trimethoprim and sulfonamide antibiotics in agricultural soil: effect of soil type, dissolved organic matter, and pH.

PubMed

Zhang, Ya-Lei; Lin, Shuang-Shuang; Dai, Chao-Meng; Shi, Lu; Zhou, Xue-Fei

2014-05-01

Use of animal manure is a main source of veterinary pharmaceuticals (VPs) in soil and groundwater through a series of migration processes. The sorption-desorption and transport of four commonly used VPs including trimethoprim (TMP), sulfapyridine, sulfameter, and sulfadimethoxine were investigated in three soil layers taken from an agricultural field in Chongming Island China and two types of aqueous solution (0.01 M CaCl2 solution and wastewater treatment plant effluent). Results from sorption-desorption experiments showed that the sorption behavior of selected VPs conformed to the Freundlich isotherm equation. TMP exhibited higher distribution coefficients (K d = 6.73-9.21) than other sulfonamides (K d = 0.03-0.47), indicating a much stronger adsorption capacity of TMP. The percentage of desorption for TMP in a range of 8-12 % is not so high to be considered significant. Low pH (

Origami-based mechanical metamaterials with tunable frequency band structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yasuda, Hiromi; Pratt, Riley; Yang, Jinkyu

2017-04-01

We investigate wave dynamics in origami-based mechanical metamaterials composed of bellows-like origami structures, specifically the Tachi-Miura Polyhedron (TMP). One of the unique features of the TMP is that its structural deformations take place only along the crease lines, therefore the structure can be made of rigid plates and hinges. By utilizing this feature, we introduce linear torsional springs to model the crease lines and derive the force and displacement relationship of the TMP structure along the longitudinal direction. Our analysis shows strain softening/hardening behaviors in compression/tensile regions respectively, and the force-displacement curve can be manipulated by altering the initial configuration of the TMP (e.g., the initial folding angle). We also fabricate physical prototypes and measure the force-displacement behavior to verify our analytical model. Based on this static analysis on the TMP, we simplify the TMP structure into a linkage model, preserving the tunable strain softening/hardening behaviors. Dynamic analysis is also conducted numerically to analyze the frequency response of the simplified TMP unit cell under harmonic excitations. The simplified TMP exhibits a transition between linear and nonlinear behaviors, which depends on the amplitude of the excitation and the initial configuration. In addition, we design a 1D system composed of simplified TMP unit cells and analyze the relationship between frequency and wave number. If two different configurations of the unit cell (e.g., different initial folding angles) are connected in an alternating arrangement, the system develops frequency bandgaps. These unique static/dynamic behaviors can be exploited to design engineering devices which can handle vibrations and impact in an efficient manner.

New insights into the transformation of trimethoprim during biological wastewater treatment.

PubMed

Jewell, Kevin S; Castronovo, Sandro; Wick, Arne; Falås, Per; Joss, Adriano; Ternes, Thomas A

2016-01-01

The antibiotic trimethoprim (TMP), a micropollutant found at μg/L levels in raw wastewater, was investigated with regard to its (bio)transformation during biological wastewater treatment. A pilot-scale, nitrifying/denitrifying Sequencing Batch Reactor (SBR) fed with municipal wastewater was monitored for TMP removal during a 16-month monitoring study. Laboratory-scaled bioreactors spiked with TMP were applied to identify the transformation products (TPs). In total, six TPs could be identified from TMP. However, the TP formation was influenced by the spike concentration. At an initial concentration of 500 μg/L TMP, only two TPs were found, whereas at 5 μg/L a completely different transformation pathway led to four further TPs. At low concentrations, TMP was demethylated forming 4-desmethyl-TMP, which was then quickly hydroxylated, oxidized and cleaved forming 2,4-diaminopyrimidine-5-carboxylic acid (DAPC) via two intermediate TPs. DAPC was detected in the SBR effluent in a 3-d composite sample with 61 ng/L, which accounts for 52% of the attenuated TMP. The primary degradation at low spiking levels was best modelled by a pseudo-first order kinetic. Considering the SBR, the model predicted a TMP removal of 88-94% for the reactor, consistent with a monitoring campaign exhibiting an average removal of >83%. Both the TP formation profiles and kinetic modelling indicated that only the results from the bioreactor tests at low spike concentrations were representative of the transformation in the SBR. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Impact of axial velocity and transmembrane pressure (TMP) on ARP filter performance

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

Poirier, M.; Burket, P.

2016-02-29

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. One potential method for increasing filter flux is to adjust the axial velocity andmore » transmembrane pressure (TMP). SRR requested SRNL to conduct bench-scale filter tests to evaluate the effects of axial velocity and transmembrane pressure on crossflow filter flux. The objective of the testing was to determine whether increasing the axial velocity at the ARP could produce a significant increase in filter flux. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate and 2.5 g MST/L, processing the slurry through a bench-scale crossflow filter unit at varying axial velocity and TMP, and measuring filter flux as a function of time.« less

Therapeutic Potential of Caspofungin Combined with Trimethoprim-Sulfamethoxazole for Pneumocystis Pneumonia: A Pilot Study in Mice

PubMed Central

Lobo, Maria Luísa; Esteves, Francisco; de Sousa, Bruno; Cardoso, Fernando; Cushion, Melanie T.; Antunes, Francisco; Matos, Olga

2013-01-01

Pneumocystis pneumonia (PcP) is a major cause of mortality and morbidity in immunocompromised patients. There are limited alternative therapeutic choices to trimethoprim-sulfamethoxazole (TMP-SMX) which is the standard first line therapy/prophylaxis for PcP. The efficacy of low doses of caspofungin and caspofungin in association with TMP-SMX standard-prophylactic dose was evaluated in an experimental model of Pneumocystis. Susceptibility of Pneumocystis spp. to low doses of caspofungin and caspofungin/TMP-SMX was evaluated in Balb/c immunosuppressed mice, infected intranasally with P. murina. Caspofungin was administered once daily at 0.1 mg/kg, 0.05 mg/kg, and 0.001 mg/kg and TMP-SMX was administered by oral gavage (12.25 mg/62.5 mg/day), for 21 days. Efficacy was calculated based on the reduction in organism burden determined through quantitative fluorescent-based real-time PCR (qPCR). Serum β-1,3-D-glucan was measured as an additional marker of infection. The present data showed that caspofungin demonstrated anti-Pneumomocystis effect. However, the doses administrated were too low to achieve Pneumocystis eradication, which suggests that echinocandin treatment should not be administrated as mono-therapy. After 21 days of treatment, P. murina was not detected in the lungs of mice with either TMP-SMX or caspofungin/TMP-SMX. The results showed that, even at the lowest concentrations tested, the efficacy of caspofungin in association with TMP-SMX was higher than the efficacy of either drug used alone. The administration of caspofungin/TMP-SMX was at least 1.4 times more effective against P. murina infection than TMP-SMX used alone. The most promising result was achieved with the combination of caspofungin 0.05 mg/kg/day with TMP-SMX 12.5 mg–62.5 mg/day, which reduced the parasite burden to undetectable levels immediately at the 14th day of treatment, showing a highly marked anti-Pneumomocystis effect. These data suggest that the administration of low doses of caspofungin in combination with low doses of TMP-SMX may provide an improved treatment protocol for Pneumocystis infection clearance. PMID:23940606

Therapeutic potential of caspofungin combined with trimethoprim-sulfamethoxazole for pneumocystis pneumonia: a pilot study in mice.

PubMed

Lobo, Maria Luísa; Esteves, Francisco; de Sousa, Bruno; Cardoso, Fernando; Cushion, Melanie T; Antunes, Francisco; Matos, Olga

2013-01-01

Pneumocystis pneumonia (PcP) is a major cause of mortality and morbidity in immunocompromised patients. There are limited alternative therapeutic choices to trimethoprim-sulfamethoxazole (TMP-SMX) which is the standard first line therapy/prophylaxis for PcP. The efficacy of low doses of caspofungin and caspofungin in association with TMP-SMX standard-prophylactic dose was evaluated in an experimental model of Pneumocystis. Susceptibility of Pneumocystis spp. to low doses of caspofungin and caspofungin/TMP-SMX was evaluated in Balb/c immunosuppressed mice, infected intranasally with P. murina. Caspofungin was administered once daily at 0.1 mg/kg, 0.05 mg/kg, and 0.001 mg/kg and TMP-SMX was administered by oral gavage (12.25 mg/62.5 mg/day), for 21 days. Efficacy was calculated based on the reduction in organism burden determined through quantitative fluorescent-based real-time PCR (qPCR). Serum β-1,3-D-glucan was measured as an additional marker of infection. The present data showed that caspofungin demonstrated anti-Pneumomocystis effect. However, the doses administrated were too low to achieve Pneumocystis eradication, which suggests that echinocandin treatment should not be administrated as mono-therapy. After 21 days of treatment, P. murina was not detected in the lungs of mice with either TMP-SMX or caspofungin/TMP-SMX. The results showed that, even at the lowest concentrations tested, the efficacy of caspofungin in association with TMP-SMX was higher than the efficacy of either drug used alone. The administration of caspofungin/TMP-SMX was at least 1.4 times more effective against P. murina infection than TMP-SMX used alone. The most promising result was achieved with the combination of caspofungin 0.05 mg/kg/day with TMP-SMX 12.5 mg-62.5 mg/day, which reduced the parasite burden to undetectable levels immediately at the 14(th) day of treatment, showing a highly marked anti-Pneumomocystis effect. These data suggest that the administration of low doses of caspofungin in combination with low doses of TMP-SMX may provide an improved treatment protocol for Pneumocystis infection clearance.

Solar photocatalytic treatment of trimethoprim in four environmental matrices at a pilot scale: transformation products and ecotoxicity evaluation.

PubMed

Michael, I; Hapeshi, E; Osorio, V; Perez, S; Petrovic, M; Zapata, A; Malato, S; Barceló, D; Fatta-Kassinos, D

2012-07-15

The pilot-scale solar degradation of trimethoprim (TMP) in different water matrices (demineralized water: DW, simulated natural freshwater: SW; simulated wastewater: SWW; and real effluent: RE) was investigated in this study. DOC removal was lower in the case of SW compared to DW, which can be attributed to the presence of inorganic anions which may act as scavengers of the HO·. Furthermore, the presence of organic carbon and higher salt content in SWW and RE led to lower mineralization per dose of hydrogen peroxide compared to DW and SW. Toxicity assays in SWW and RE were also performed indicating that toxicity is attributed to the compounds present in RE and their by-products formed during solar Fenton treatment and not to the intermediates formed by the oxidation of TMP. A large number of compounds generated by the photocatalytic transformation of TMP were identified by UPLC-QToF/MS. The degradation pathway revealed differences among the four matrices; however hydroxylation, demethylation and cleavage reactions were observed in all matrices. To the best of our knowledge this is the first time that TMP degradation products have been identified by adopting a solar Fenton process at a pilot-scale set-up, using four different aqueous matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

Sustained availability of trimethoprim in drinking water to achieve higher plasma sulphonamide-trimethoprim antibacterial activity in broilers.

PubMed

Sumano, H; Hernandez, L; Gutierrez, L; Bernad-Bernad, M J

2005-02-01

(1) In order to make trimethoprim (TMP) available to broilers throughout the day, a sustained release formulation (SRF) of the drug in the form of granules was added to the water tank that supplies drinking water. (2) Broilers were initially dosed with sulphachloropiridazine-TMP (SCP-TMP 5:1) and then further medicated throughout the day, achieving in the end a dose of 30 mg/kg each of SCP and TMP (group A). Group B received a preparation with the same dose of SCP and TMP (1:1) as group A, but administered as a single dose without the SRF of TMP. Group C received the customary SCP-TMP 5:1 preparation (30 and 6 mg/kg, respectively). Water tanks were completely consumed in 3 to 4 h. (3) Broilers were bled at different times and concentration of antibacterial activity in serum determined by correlating the composite antibacterial activity of SCP and TMP with actual concentrations of these drugs by means of a microbiological agar diffusion assay. (4) Time vs serum concentrations of activity were higher in group B; the increments in the maximum serum concentration for group B over groups A and C being 39 and 67%, respectively. (5) However, the sustained concentration of activity over time, measured as the area under the cu)rve, was highest in group A. Group B had higher values for area under the curve than group C. (6) An additional dose of TMP to achieve 30 mg/kg of both SCP and TMP improves the serum concentration of this combination over the customary 5:1 proportion. The best values for sustaining antibacterial activity were obtained using a 1:1 ratio as in group A. The use of a SRF as in group A may translate into better clinical results.

Optimization of esterification of oleic acid and trimethylolpropane (TMP) and pentaerythritol (PE)

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

Mahmud, Hamizah Ammarah; Salimon, Jumat

Vegetable oil (VO) is the most potential alternative to replace mineral oil for lubricant due to better lubricating properties and great physicochemical properties. Chemical modification has to be done to overcome low temperature performance and low oxidation instability due to the presence of β-hydrogen atoms of glycerol molecule. The optimization of esterification of oleic acid and polyhydric alcohol with sulfuric acid catalyst was carried out to find the optimum conditions with the highest yield. Reeaction variables such as; molar ratio, temperature, duration and catalyst concentration. Two types of polyhydric alcohol have been used; TMP and PE. The optimum results showedmore » oleic acid successfully converted 91.2% ester TMP and 92.7% ester PE at duration: 5 hours (Ester TMP), 6 hours (Ester PE); temperature: 150°C (ester TMP), 180°C (Ester PE); catalyst concentration: 1.5% (w/w); and mol ratio: 3.9:1 (ester TMP), 4.9:1 (ester PE). From the data obtained, mole ratio showed most influenced factors to the increasing yields of ester conversions.. The TMP/PE ester was confirmed using gas chromatography (GC-FID), Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR)« less

Concurrent material-fabrication optimization of metal-matrix laminates under thermo-mechanical loading

NASA Technical Reports Server (NTRS)

Saravanos, D. A.; Morel, M. R.; Chamis, C. C.

1991-01-01

A methodology is developed to tailor fabrication and material parameters of metal-matrix laminates for maximum loading capacity under thermomechanical loads. The stresses during the thermomechanical response are minimized subject to failure constrains and bounds on the laminate properties. The thermomechanical response of the laminate is simulated using nonlinear composite mechanics. Evaluations of the method on a graphite/copper symmetric cross-ply laminate were performed. The cross-ply laminate required different optimum fabrication procedures than a unidirectional composite. Also, the consideration of the thermomechanical cycle had a significant effect on the predicted optimal process.

In vitro enamel remineralization capacity of composite resins containing sodium trimetaphosphate and fluoride.

PubMed

Tiveron, Adelisa Rodolfo Ferreira; Delbem, Alberto Carlos Botazzo; Gaban, Gabriel; Sassaki, Kikue Takebayashi; Pedrini, Denise

2015-11-01

This study evaluated the in vitro enamel remineralization capacity of experimental composite resins containing sodium trimetaphosphate (TMP) combined or not with fluoride (F). Bovine enamel slabs were selected upon analysis of initial surface hardness (SH1) and after induction of artificial carious lesions (SH2). Experimental resins were as follows: resin C (control—no sodium fluoride (NaF) or TMP), resin F (with 1.6% NaF), resin TMP (with 14.1% TMP), and resin TMP/F (with NaF and TMP). Resin samples were made and attached to enamel slabs (n = 12 slabs per material). Those specimens (resin/enamel slab) were subjected to pH cycling to promote remineralization, and then final surface hardness (SH3) was measured to calculate the percentage of surface hardness recovery (%SH). The integrated recovery of subsurface hardness (ΔKHN) and F concentration in enamel were also determined. Data was analyzed by ANOVA and Student-Newman-Keuls test (p < 0.05). Resins F and TMP/F showed similar SH3 values (p = 0.478) and %SH (p = 0.336) and differed significantly from the other resins (p < 0.001). Considering ΔKHN values, resin TMP/F presented the lowest area of lesion (p < 0.001). The presence of F on enamel was different among the fluoridated resins (p = 0.042), but higher than in the other resins (p < 0.001). The addition of TMP to a fluoridated composite resin enhanced its capacity for remineralization of enamel in vitro. The combination of two agents with action on enamel favored remineralization, suggesting that composite resins containing sodium trimetaphosphate and fluoride could be indicated for clinical procedures in situations with higher cariogenic challenges.

Pharmacokinetics of sulfamethoxazole and trimethoprim in Pacific white shrimp, Litopenaeus vannamei, after oral administration of single-dose and multiple-dose.

PubMed

Ma, Rongrong; Wang, Yuan; Zou, Xiong; Hu, Kun; Sun, Beibei; Fang, Wenhong; Fu, Guihong; Yang, Xianle

2017-06-01

The tissue distribution and depletion of sulfamethoxazole (SMZ) and trimethoprim (TMP) were studied in Pacific white shrimp, Litopenaeus vannamei, after single-dose and multiple-dose oral administration of SMZ-TMP (5:1) via medicated feed. In single-dose oral administration, shrimps were fed once at a dose of 100 mg/kg (drug weight/body weight). In multiple-dose oral administration, shrimps were fed three times a day for three consecutive days at a dose of 100mg/kg. The results showed the kinetic characteristic of SMZ was different from TMP in Pacific white shrimp. In the single-dose administration, the SMZ was widely distributed in the tissues, while TMP was highly concentrated in the hepatopancreas. The t 1/2z values of SMZ were larger and persist longer than TMP in Pacific white shrimp. In the multiple-dose administration, SMZ accumulated well in the tissues, and reached steady state level after successive administrations, while TMP did not. TMP concentration even appeared the downward trend with the increase of drug times. Compared with the single dose, the t 1/2z values of SMZ in hepatopancreas (8.22-11.33h) and muscle (6.53-10.92h) of Pacific white shrimps rose, but the haemolymph dropped (13.76-11.03) in the multiple-dose oral administration. Meanwhile, the corresponding values of TMP also rose in hepatopancreas (4.53-9.65h) and muscle (2.12-2.71h), and declined in haemolymph (7.38-5.25h) following single-dose and multiple-dose oral administration in Pacific white shrimps. In addition, it is worth mentioning that the ratios of SMZ and TMP were unusually larger than the general aim ratio. Copyright © 2017 Elsevier B.V. All rights reserved.

Urinary Concentrations and Antibacterial Activities of Nitroxoline at 250 Milligrams versus Trimethoprim at 200 Milligrams against Uropathogens in Healthy Volunteers

PubMed Central

Münch, Fabian; Pilatz, Adrian; Bärmann, Birte; Weidner, Wolfgang; Wagenlehner, Christine M.; Straubinger, Marion; Blenk, Holger; Pfister, Wolfgang; Kresken, Michael; Naber, Kurt G.

2014-01-01

Because of the increasing bacterial resistance of uropathogens against standard antibiotics, such as trimethoprim (TMP), older antimicrobial drugs, such as nitroxoline (NTX), should be reevaluated. This randomized crossover study investigated the urinary concentrations of parent drugs and their metabolites and their antibacterial activities (urinary inhibitory titers [UITs] and urinary bactericidal titers [UBTs]) against uropathogens at three different urinary pH values within 24 h in six healthy volunteers after a single oral dose of NTX at 250 mg versus TMP at 200 mg. In three additional volunteers, urinary bactericidal kinetics (UBK) were studied after oral administration of NTX at 250 mg three times a day. The mean urinary concentrations of NTX and NTX sulfate in 24 h were 0.012 to 0.507 mg/liter and 0.28 to 27.83 mg/liter, respectively. The mean urinary concentrations of TMP were 18.79 to 41.59 mg/liter. The antibacterial activity of NTX was higher in acidic urine than in alkaline urine, and that of TMP was higher in alkaline urine than in acidic urine. The UITs and UBTs of NTX were generally lower than those of TMP except for a TMP-resistant Escherichia coli strain, for which NTX showed higher UITs/UBTs than did TMP. UBK showed mainly bacteriostatic activity of NTX in urine. NTX exhibits mainly bacteriostatic activity and TMP also shows bactericidal activity in urine against susceptible strains. NTX is a more active antibacterial in acidic urine, and TMP is more active in alkaline urine. The cumulative effects of multiple doses or inhibition of bacterial adherence could not be evaluated. (This study has been registered at EudraCT under registration no. 2009-015631-32.) PMID:24217699

Tetramethylpyrazine reverses intracerebroventricular streptozotocin-induced memory deficits by inhibiting GSK-3β.

PubMed

Lu, Fen; Li, Xu; Li, Wei; Wei, Ke; Yao, Yong; Zhang, Qianlin; Liang, Xinliang; Zhang, Jiewen

2017-08-01

Brain dysfunction, especially cognitive impairment, is one of the main complications in Alzheimer's disease (AD), which threatens the health of 46.8 million people worldwide. At present, the pathogenesis of cognitive dysfunction is only partially understood, and effective therapies for memory loss in AD remain elusive. Tetramethylpyrazine (TMP) is one of the major bioactive compounds purified from Chuanxiong, a Chinese herb used for the treatment of neurovascular and cardiovascular diseases. The neuroprotective properties of TMP are evident in some neurodegenerative diseases, including Parkinson's disease. However, whether TMP plays a neuroprotective role in AD is still unknown. Here, we report that 2-week treatment with TMP rescued both short-term and long-term fear memory impairment induced by intracerebroventricular injection of streptozotocin in a well-known AD rat model. Administration of TMP also restored spatial learning and memory retention abilities in streptozotocin-injected rats. Furthermore, TMP inhibited the activity of GSK-3β, an important kinase that mediates hippocampal synaptic and memory disorders in diabetes mellitus. Finally, we found that TMP treatment restored the function of cholinergic neurons. Our data suggest that dietary uptake of TMP can provide protection against memory loss in AD, and the inhibition of GSK-3β may play an important role in this protective effect. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Simultaneous determination of trimethoprim and sulfamethoxazole in dried plasma and urine spots.

PubMed

Gonzalez, Daniel; Melloni, Chiara; Poindexter, Brenda B; Yogev, Ram; Atz, Andrew M; Sullivan, Janice E; Mendley, Susan R; Delmore, Paula; Delinsky, Amy; Zimmerman, Kanecia; Lewandowski, Andrew; Harper, Barrie; Lewis, Kenneth C; Benjamin, Daniel K; Cohen-Wolkowiez, Michael

2015-01-01

Trimethoprim-sulfamethoxazole (TMP-SMX) is an antimicrobial drug combination commonly prescribed in children and adults. The study objectives were to validate and apply an HPLC-MS/MS method to quantify TMP-SMX in dried plasma spots (DPS) and dried urine spots (DUS), and perform a comparability analysis with liquid matrices. For TMP the validated range was 100-50,000 ng/ml for DPS and 500-250,000 ng/ml for DUS; for SMX, the validated range was 1000-500,000 ng/ml for both DPS and DUS. Good agreement was noted between DPS/DUS and liquid plasma and urine samples for TMP, while only modest agreement was observed for SMX in both matrices. A precise, accurate and reproducible method was developed to quantify TMP-SMX in DPS and DUS samples.

Trimethoprim-Sulfamethoxazole Prophylaxis During Live Malaria Sporozoite Immunization Induces Long-Lived, Homologous, and Heterologous Protective Immunity Against Sporozoite Challenge.

PubMed

Hobbs, Charlotte V; Anderson, Charles; Neal, Jillian; Sahu, Tejram; Conteh, Solomon; Voza, Tatiana; Langhorne, Jean; Borkowsky, William; Duffy, Patrick E

2017-01-01

Trimethoprim-sulfamethoxazole (TMP-SMX) is widely used in malaria-endemic areas in human immunodeficiency virus (HIV)-infected children and HIV-uninfected, HIV-exposed children as opportunistic infection prophylaxis. Despite the known effects that TMP-SMX has in reducing clinical malaria, its impact on development of malaria-specific immunity in these children remains poorly understood. Using rodent malaria models, we previously showed that TMP-SMX, at prophylactic doses, can arrest liver stage development of malaria parasites and speculated that TMP-SMX prophylaxis during repeated malaria exposures would induce protective long-lived sterile immunity targeting pre-erythrocytic stage parasites in mice. Using the same models, we now demonstrate that repeated exposures to malaria parasites during TMP-SMX administration induces stage-specific and long-lived pre-erythrocytic protective anti-malarial immunity, mediated primarily by CD8 + T-cells. Given the HIV infection and malaria coepidemic in sub-Saharan Africa, clinical studies aimed at determining the optimum duration of TMP-SMX prophylaxis in HIV-infected or HIV-exposed children must account for the potential anti-infection immunity effect of TMP-SMX prophylaxis. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Effect of fluoride toothpaste with nano-sized trimetaphosphate on enamel demineralization: An in vitro study.

PubMed

Danelon, Marcelle; Pessan, Juliano Pelim; Souza-Neto, Francisco Nunes; de Camargo, Emerson Rodrigues; Delbem, Alberto Carlos Botazzo

2017-06-01

This study evaluated the effect of toothpastes containing 1100ppm F associated or not with micrometric or nano-sized sodium trimetaphosphate (TMP) on enamel demineralization in vitro, using a pH cycling model. Bovine enamel blocks (4mm×4mm, n=96) were randomly allocated into eight groups (n=12), according to the test toothpastes: Placebo (without fluoride or TMP); 1100ppm F (1100F); 1100F plus micrometric TMP at concentrations of 1%, 3% or 6%; and 1100F plus nanosized TMP at 1%, 3% or 6%. Blocks were treated 2×/day with slurries of toothpastes and submitted to a pH cycling regimen for five days. Next, final surface hardness (SHf), integrated hardness loss (IHL), differential profile of integrated hardness loss (ΔIHL) and enamel fluoride (F) concentrations were determined. Data were analyzed by ANOVA and Student-Newman-Keuls' test (p<0.05). The use of 1100F/3%TMPnano led to SHf 30% higher (p<0.001) and IHL∼80% lower (p<0.001) when compared to 1100F. This toothpaste also resulted in ∼64% reduction of mineral loss (ΔIHL) when compared to 1100F. Moreover, the addition of nano-sized TMP promoted increases in enamel F uptake of 90%, 160% and 100%, respectively for the concentrations of 1%, 3% and 6%, when compared to 1100F (p<0.001). The addition of nano-sized TMP at 3% to a conventional toothpaste significantly decreased enamel demineralization when compared to its counterparts without TMP or supplemented with micrometric TMP. Copyright © 2017 Elsevier Ltd. All rights reserved.

High prevalence of antimicrobial resistance among Shigella isolates in the United States tested by the National Antimicrobial Resistance Monitoring System from 1999 to 2002.

PubMed

Sivapalasingam, Sumathi; Nelson, Jennifer M; Joyce, Kevin; Hoekstra, Mike; Angulo, Frederick J; Mintz, Eric D

2006-01-01

Shigella spp. infect approximately 450,000 persons annually in the United States, resulting in over 6,000 hospitalizations. Since 1999, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has tested every 10th Shigella isolate from 16 state or local public health laboratories for susceptibility to 15 antimicrobial agents. From 1999 to 2002, NARMS tested 1,604 isolates. Among 1,598 isolates identified to species level, 1,278 (80%) were Shigella sonnei, 295 (18%) were Shigella flexneri, 18 (1%) were Shigella boydii, and 7 (0.4%) were Shigella dysenteriae. Overall, 1,251 (78%) were resistant to ampicillin and 744 (46%) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Prevalence of TMP-SMX- or ampicillin- and TMP-SMX-resistant Shigella sonnei isolates varied by geographic region, with lower rates in the South and Midwest regions (TMP-SMX resistance, 27% and 30%, respectively; ampicillin and TMP-SMX resistance, 25% and 22%, respectively) and higher rates in the East and West regions (TMP-SMX resistance, 66% and 80%, respectively; ampicillin and TMP-SMX resistance, 54% and 65%, respectively). Nineteen isolates (1%) were resistant to nalidixic acid (1% of S. sonnei and 2% of S. flexneri isolates); 12 (63%) of these isolates had decreased susceptibility to ciprofloxacin. One S. flexneri isolate was resistant to ciprofloxacin. All isolates were susceptible to ceftriaxone. Since 1986, resistance to ampicillin and TMP-SMX has dramatically increased. Shigella isolates in the United States remain susceptible to ciprofloxacin and ceftriaxone.

High Prevalence of Antimicrobial Resistance among Shigella Isolates in the United States Tested by the National Antimicrobial Resistance Monitoring System from 1999 to 2002

PubMed Central

Sivapalasingam, Sumathi; Nelson, Jennifer M.; Joyce, Kevin; Hoekstra, Mike; Angulo, Frederick J.; Mintz, Eric D.

2006-01-01

Shigella spp. infect approximately 450,000 persons annually in the United States, resulting in over 6,000 hospitalizations. Since 1999, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has tested every 10th Shigella isolate from 16 state or local public health laboratories for susceptibility to 15 antimicrobial agents. From 1999 to 2002, NARMS tested 1,604 isolates. Among 1,598 isolates identified to species level, 1,278 (80%) were Shigella sonnei, 295 (18%) were Shigella flexneri, 18 (1%) were Shigella boydii, and 7 (0.4%) were Shigella dysenteriae. Overall, 1,251 (78%) were resistant to ampicillin and 744 (46%) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Prevalence of TMP-SMX- or ampicillin- and TMP-SMX-resistant Shigella sonnei isolates varied by geographic region, with lower rates in the South and Midwest regions (TMP-SMX resistance, 27% and 30%, respectively; ampicillin and TMP-SMX resistance, 25% and 22%, respectively) and higher rates in the East and West regions (TMP-SMX resistance, 66% and 80%, respectively; ampicillin and TMP-SMX resistance, 54% and 65%, respectively). Nineteen isolates (1%) were resistant to nalidixic acid (1% of S. sonnei and 2% of S. flexneri isolates); 12 (63%) of these isolates had decreased susceptibility to ciprofloxacin. One S. flexneri isolate was resistant to ciprofloxacin. All isolates were susceptible to ceftriaxone. Since 1986, resistance to ampicillin and TMP-SMX has dramatically increased. Shigella isolates in the United States remain susceptible to ciprofloxacin and ceftriaxone. PMID:16377666

Simultaneous determination of trimethoprim and sulfamethoxazole in dried plasma and urine spots

PubMed Central

Gonzalez, Daniel; Melloni, Chiara; Poindexter, Brenda B; Yogev, Ram; Atz, Andrew M; Sullivan, Janice E; Mendley, Susan R; Delmore, Paula; Delinsky, Amy; Zimmerman, Kanecia; Lewandowski, Andrew; Harper, Barrie; Lewis, Kenneth C; Benjamin, Daniel K; Cohen-Wolkowiez, Michael

2015-01-01

Background: Trimethoprim-sulfamethoxazole (TMP-SMX) is an antimicrobial drug combination commonly prescribed in children and adults. The study objectives were to validate and apply an HPLC–MS/MS method to quantify TMP-SMX in dried plasma spots (DPS) and dried urine spots (DUS), and perform a comparability analysis with liquid matrices. Results: For TMP the validated range was 100–50,000 ng/ml for DPS and 500–250,000 ng/ml for DUS; for SMX, the validated range was 1000–500,000 ng/ml for both DPS and DUS. Good agreement was noted between DPS/DUS and liquid plasma and urine samples for TMP, while only modest agreement was observed for SMX in both matrices. Conclusion: A precise, accurate and reproducible method was developed to quantify TMP-SMX in DPS and DUS samples. PMID:26039810

The Influence of Hyperlipidemia on Endothelial Function of FPN1 Tek-Cre Mice and the Intervention Effect of Tetramethylpyrazine.

PubMed

Sun, Ming-Yue; Zhang, Miao; Chen, Shui-Ling; Zhang, Shu-Ping; Guo, Chun-Yu; Wang, Jing-Shang; Liu, Xin; Miao, Yang; Yin, Hui-Jun

2018-01-01

Systemic iron homeostasis is strictly governed in mammals; however, disordered iron metabolism (such as excess iron burden) is recognized as a risk factor for various types of diseases including AS (Atherosclerosis). The hepcidin-ferroportin axis plays the key role in regulation of iron homeostasis and modulation of this signaling could be a potential therapeutic strategy in the treatment of these diseases. TMP (Tetramethylpyrazine) has been reported to have therapeutical effect on AS. Here, we aimed to investigate the effect of iron overload under hyperlipidemia condition on the endothelial injury, inflammation and oxidative stress by employing FPN1 Tek-cre mouse model with or without TMP intervention. Subjects for this study were 80 FPN1 Tek-cre mice and 40 C57BL/6 mice and we randomly divided them into six groups: Group N: C57BL/6 mice with normal diet, Group M: C57BL/6 mice with high-fat diet, Group FN: FPN1 Tek-cre mice with normal diet, Group FNT: FPN1 Tek-cre mice with normal diet and TMP injection, Group FM: FPN1 Tek-cre mice with high-fat diet, Group FMT: FPN1 Tek-cre mice with high-fat diet and TMP injection. After seven days of treatment, blood samples were obtained to detect the levels of blood lipids, Hepcidin, NO, ET-1, ROS, MDA, SOD, IL-1, IL-6 and TNF-α respectively. The liver and aorta were used for testing the lipid deposition by using hematoxylin and eosin(HE). Hyperlipidemia could cause iron overload in the aorta and increased serum hepcidin level, particularly in FPN1 Tek-cre mice, and can be reversed by TMP intervention. Knockout of Fpn1 induced increase of serum hepcidin, exacerbated endothelial dysfunction, oxidative stress and inflammatory response, particularly under hyperlipidemia condition. TMP intervention attenuated these processes. Our study signifies the potential application of certain natural compounds to ameliorating iron disorders induced by hyperlipidemia and protecting on endothelial function through modulation of hepcidin-ferroportin signaling. © 2018 The Author(s). Published by S. Karger AG, Basel.

The production of fine grained magnesium alloys through thermomechanical processing for the optimization of microstructural and mechanical properties

NASA Astrophysics Data System (ADS)

Young, John Paul

The low density and high strength to weight ratio of magnesium alloys makes them ideal candidates to replace many of the heavier steel and aluminum alloys currently used in the automotive and other industries. Although cast magnesium alloys components have a long history of use in the automotive industry, the integration of wrought magnesium alloys components has been hindered by a number of factors. Grain refinement through thermomechanical processing offers a possible solution to many of the inherent problems associated with magnesium alloys. This work explores the development of several thermomechanical processing techniques and investigates their impact on the microstructural and mechanical properties of magnesium alloys. In addition to traditional thermomechanical processing, this work includes the development of new severe plastic deformation techniques for the production of fine grain magnesium plate and pipe and develops a procedure by which the thermal microstructural stability of severely plastically deformed microstructures can be assessed.

Poor rectal absorption of trimethoprim/sulphamethoxazole in treating Pneumocystis carinii pneumonia.

PubMed Central

Dorr, R. T.; Powell, J. R.; Heick, M.; Barry, D. W.

1981-01-01

A 24-year-old female with Hodgkin's disease and Pneumocystis carinii pneumonia was tested with trimethoprim/sulphamethoxazole (TMP/SMX) tablets. Because treatment failure was feared owing to chronic emesis potentially resulting in incomplete drug absorption, the same TMP/SMX dose was administered by rectal suppositories after the 5th day of oral dosing. The relative fractions (rectal/oral) or the suppository dose absorbed for TMP and SMX were 3.0% and 19.5% respectively. When TMP/SMX treatment is required and the oral route is not practical, the investigational i.v. preparation should be obtained. PMID:6973756

Tetramethylpyrazine suppresses transient oxygen-glucose deprivation-induced connexin32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathway in cultured hippocampal neurons.

PubMed

Gong, Gu; Yuan, Libang; Cai, Lin; Ran, Maorong; Zhang, Yulan; Gong, Huaqu; Dai, Xuemei; Wu, Wei; Dong, Hailong

2014-01-01

Tetramethylpyrazine (TMP) has been widely used in China as a drug for the treatment of various diseases. Recent studies have suggested that TMP has a protective effect on ischemic neuronal damage. However, the exact mechanism is still unclear. This study aims to investigate the mechanism of TMP mediated ischemic hippocampal neurons injury induced by oxygen-glucose deprivation (OGD). The effect of TMP on hippocampal neurons viability was detected by MTT assay, LDH release assay and apoptosis rate was measured by flow cytometry. TMP significantly suppressed neuron apoptosis in a concentration-dependent manner. TMP could significantly reduce the elevated levels of connexin32 (Cx32) induced by OGD. Knockdown of Cx32 by siRNA attenuated OGD injury. Moreover, our study showed that viability was increased in siRNA-Cx32-treated-neurons, and neuron apoptosis was suppressed by activating Bcl-2 expression and inhibiting Bax expression. Over expression of Cx32 could decrease neurons viability and increase LDH release. Furthermore, OGD increased phosphorylation of ERK1/2 and p38, whose inhibitors relieved the neuron injury and Cx32 up-regulation. Taken together, TMP can reverse the OGD-induced Cx32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathways.

Development of an inhalation physiologically based pharmacokinetic (PBPK) model for 2,2, 4-trimethylpentane (TMP) in male Long-Evans rats using gas uptake experiments.

EPA Science Inventory

2,2,4-Trimethylpentane (TMP) is a volatile colorless liquid used primarily to increase the octane rating of combustible fuels. TMP is released in the environment through the manufacture, use, and disposal of products associated with the gasoline and petroleum industry. Short-term...

DEVELOPMENT OF A PHYSIOLOGICALLY-BASED PHARMACOKINETIC (PBPK) MODEL FOR THE INHALATION OF 2,2,4-TRIMETHYLPENTANE (TMP) IN LONG EVANS RATS.

EPA Science Inventory

TMP (2,2,4-trimethylpentane,“isooctane”) is a colorless liquid used primarily in the alkylation of isobutene and butylene reactions to derive high-octane fuels. TMP is released in the environment through the manufacture, use, and disposal of products associated with the gasoline ...

Effect of toothpaste with nano-sized trimetaphosphate on dental caries: In situ study.

PubMed

Danelon, Marcelle; Pessan, Juliano Pelim; Neto, Francisco Nunes Souza; de Camargo, Emerson Rodrigues; Delbem, Alberto Carlos Botazzo

2015-07-01

This in situ study was to evaluate the remineralizing effect of a fluoride toothpaste supplemented with nano-sized sodium trimetaphosphate (TMP). This blind and cross-over study was performed in 4 phases of 3 days each. Twelve subjects used palatal appliances containing four bovine enamel blocks with artificial caries lesions. Volunteers were randomly assigned into the following treatment groups: Placebo (without F and TMP); 1100 ppm F (1100), 1100 supplemented with 3% micrometric TMP (1100 TMP) and with nano-sized TMP (1100 TMPnano). Volunteers were instructed to brush their natural teeth with the palatal appliances in the mouth during 1min (3 times/day), so that blocks were treated with natural slurries of toothpastes. After each phase, the percentage of surface hardness recovery (%SHR), integrated mineral recovery (IMR) and integrated differential mineral area profile (ΔIMR) in enamel lesions were calculated. F in enamel was also determined. Data were analyzed by ANOVA and Student-Newman-Keuls test. Enamel surface became 20% harder when treated with 1100 TMPnano in comparison with 1100 (p<0.001). 1100 TMPnano showed remineralizing capacity (IMR; ΔIMR) 66% higher when compared with 1100 TMP (p<0.001). Enamel F uptake in the 1100 TMPnano group was 2-fold higher when compared to its counterpart without TMP (p<0.001). The addition of 3% TMPnano to a conventional toothpaste was able to promote an additional remineralizing effect of artificial caries lesions. Toothpaste containing 1100 ppm F associated with TMPnano showed a potential of higher remineralization to 1100 ppm F and 1100 ppm F micrometric TMP. Copyright © 2015 Elsevier Ltd. All rights reserved.

Infections during induction therapy for children with acute lymphoblastic leukemia. the role of sulfamethoxazole-trimethoprim (SMX-TMP) prophylaxis.

PubMed

Rungoe, Christine; Malchau, Emma Louise; Larsen, Line Nordahl; Schroeder, Henrik

2010-08-01

Bacteremias are frequent during induction therapy for acute lymphoblastic leukemia (ALL) in children. Antibacterial prophylaxis therapy may thus be warranted. The purpose of this study was to analyze the rate of infections during induction therapy in two cohorts of children with ALL where one cohort received prophylactic sulfamethoxazole-trimethoprim (SMX-TMP). All infections were registered through a retrospective non-randomized review of medical records of 171 consecutive children newly diagnosed with ALL below 15 years of age at diagnosis. A total of 85 children treated from 1992 to 2000 did not receive SMX-TMP, whereas 86 children treated from 2000 to 2008 received SMX-TMP 20 mg/kg in one daily oral dose during induction therapy. A total of 26% of all children had no febrile episodes during induction. Infections were more frequent in children below 5 years of age. Significantly fewer children receiving SMX-TMP developed fever (17% vs. 34%, P = 0.02) and bacteremia (20% vs. 45%, P = 0.0003). Especially children with non-high risk criteria had fewer infections when receiving prophylaxis. When adjusting for age, type of catheter, and SMX-TMP prophylaxis on the risk of bacteremia by a multiple Cox regression analysis, we found that age and prophylaxis, but not the type of catheter, were associated with a significantly reduced risk of bacteremia. Children with ALL receiving SMX-TMP prophylaxis during induction therapy experienced fewer febrile episodes, fewer days with fever demanding intravenous antibiotic treatment, and fewer episodes of bacteremia. Both SMX-TMP prophylaxis and age played significant independent roles for the occurrence of bacteremia. (c) 2010 Wiley-Liss, Inc.

Renal Insufficiency in Concert with Renin-angiotensin-aldosterone Inhibition Is a Major Risk Factor for Hyperkalemia Associated with Low-dose Trimethoprim-sulfamethoxazole in Adults.

PubMed

Higashioka, Kazuhiko; Niiro, Hiroaki; Yoshida, Kenji; Oryoji, Kensuke; Kamada, Kazuo; Mizuki, Shinichi; Yokota, Eisuke

2016-01-01

Low-dose trimethoprim-sulfamethoxazole (TMP-SMX) is commonly used to prevent pneumocystis pneumonia in daily practice. Previous reports have shown a relationship between high- or standard-dose of TMP-SMX and hyperkalemia, however it remains unclear whether this is true for low-dose TMP-SMX. In this study we sought to determine the risk factors for hyperkalemia associated with low-dose TMP-SMX. In this retrospective cohort study, 186 consecutive adult patients who received TMP-SMX as prophylaxis for pneumocystis pneumonia from January 2014 to January 2015 were evaluated. Data on the patients' age, gender, baseline estimated glomerular filtration rate (eGFR), baseline serum potassium, maximum serum potassium, duration reaching the maximal serum potassium level, dosage, and concomitant use of angiotensin-converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB), β-blockers, non-steroidal anti-inflammatory drugs and potassium-sparing diuretics were retrospectively collected. Hyperkalemia was defined as a serum potassium level ≥5 mEq/L. Univariate and multivariate analyses were performed. The median age of the patients was 66 years and 51.1% were men. Hyperkalemia associated with low-dose TMP-SMX was observed in 32 patients (17.2%). The median duration to reach the maximal serum potassium level was 12 days. The multivariate logistic regression analysis identified renal insufficiency to be a major risk factor for hyperkalemia associated with low-dose TMP-SMX (eGFR <60 mL/min/1.73 m(2), adjusted OR 4.62). Moreover, in the subpopulation of patients with renal insufficiency, ACEi/ARB use was considered to be a major risk factor for hyperkalemia (adjusted OR 3.96). Renal insufficiency in concert with ACEi/ARB use is a major risk factor for hyperkalemia induced by low-dose TMP-SMX.

Photooxidation of Trimethyl Phosphite in Nitrogen, Oxygen, and para-Hydrogen Matrixes at Low Temperatures.

PubMed

Ramanathan, N; Sundararajan, K; Gopi, R; Sankaran, K

2017-03-16

Trimethyl phosphite (TMPhite) was photooxidized to trimethyl phosphate (TMP) in N 2 , O 2 , and para-H 2 matrixes at low temperatures to correlate the conformational landscape of these two molecules. The photooxidation produced the trans (TGG)-rich conformer with respect to the ground state gauche (GGG) conformer of TMP in N 2 and O 2 matrixes, which has diverged from the conformational composition of freshly deposited pure TMP in the low-temperature matrixes. The enrichment of the trans conformer in preference to the gauche conformer of TMP during photooxidation is due to the TMPhite precursor, which exists exclusively in the trans conformer. Interestingly, whereas the photooxidized TMP molecule suffers site effects possibly due to the local asymmetry in N 2 and O 2 matrixes, in the para-H 2 matrix owing to the quantum crystal nature the site effects were observed to be self-repaired.

Successful treatment of severe Pneumocystis pneumonia in an immunosuppressed patient using caspofungin combined with clindamycin: a case report and literature review.

PubMed

Li, Hongjuan; Huang, Haoming; He, Hangyong

2016-11-11

Pneumocystis jirovecii is responsible for Pneumocystis pneumonia (PCP), which occurs almost exclusively in immunocompromised individuals. Trimethoprim-sulfamethoxazole (TMP-SMZ) is regarded as the first-line treatment and prophylaxis for P. jirovecii infection, but the frequency of adverse reactions and newly emerged antibiotic resistance limit its use. Ulcerations and hemorrhages involving the tongue were noted secondary to TMP-SMZ desensitization against PCP in a 46-year-old male who had previously been diagnosed with IgA nephropathy and sustained prolonged corticosteroid therapy. There was an urgent need for an alternative regimen due to the severe response to TMP-SMZ. The patient was successfully treated with a combination therapy of caspofungin and clindamycin. Caspofungin combined with clindamycin is an optional treatment for PCP when treatment with TMP-SMZ fails or in patients who cannot tolerate TMP-SMZ.

Determinants of Quinolone versus Trimethoprim-Sulfamethoxazole Use for Outpatient Urinary Tract Infection

PubMed Central

Stuck, Anna K.; Täuber, Martin G.; Schabel, Maria; Lehmann, Thomas; Suter, Herbert

2012-01-01

Quinolones are increasingly favored over trimethoprim-sulfamethoxazole (TMP-SMX) for empirical treatment of uncomplicated urinary tract infection (UTI). This is associated with increasing resistance toward this broad-spectrum group of antibiotics. Our objective is to describe the prescribing patterns and identify determinants of the choice between TMP-SMX and quinolones for outpatient UTI treatment in Switzerland. An ongoing national Sentinel surveillance system was used to study 11,799 antibiotic prescriptions for UTI in adult outpatients and associated physician and patient factors between 2006 and 2008, to compare the prescription of quinolones versus that of TMP-SMX for treatment of UTI. Most UTI episodes were diagnosed as cystitis (90%). TMP-SMX was prescribed for one-fifth (22%) of UTIs. Independent predictors for prescribing quinolones were pyelonephritis and physicians with low thresholds for prescribing antibiotics for upper respiratory tract infections (“high prescribers”), whereas female patients were more likely to receive TMP-SMX. High-prescribing physicians also more often cared for patients who themselves favor antibiotic treatment (P < 0.001). Quinolones are commonly prescribed to outpatients with UTI. Nonclinical factors influence the choice of quinolones versus TMP-SMX, which may provide opportunities for interventions to improve prescribing patterns and control quinolone resistance. PMID:22232276

Tetramethylpyrazine-Loaded Hydrogels: Preparation, Penetration Through a Subcutaneous-Mucous-Membrane Model, and a Molecular Dynamics Simulation.

PubMed

Xia, Hongmei; Xu, Yinxiang; Cheng, Zhiqing; Cheng, Yongfeng

2017-07-01

Tetramethylpyrazine (TMP) was extracted from Ligusticum chuanxiong hort. The compound is known to have a variety of medicinal functions; in particular, it is used for the treatment of cerebral ischemic diseases. TMP-loaded hydrogels offer an excellent preparation with the capacity to bypass the blood-brain barrier, allowing treatment of the brain through intranasal administration. We prepared TMP-loaded hydrogels using carbomer 940 and evaluated the release of TMP from the hydrogel. We determined the release rate using Franz-type diffusion cell experiments with a subcutaneous-mucous-membrane model and also by a molecular dynamics (MD) simulation. In general, the former method was more complicated than the latter was. The dynamic behavior of TMP release from the hydrogel was revealed by analysis of the mean square displacement of the trajectory in the MD simulation. The coefficient of TMP diffusion from the hydrogel was calculated at different temperatures (277, 298, and 310 K) by using MD software. The results showed that the coefficient of diffusion increased with an increase in temperature. This trend was observed both experimentally and in the MD simulation. Therefore, the MD simulation was a complementary method to verify the experimental data.

Hydrogen and methanol exchange processes for (TMP)Rh-OCH3(CH3OH) in binary solutions of methanol and benzene.

PubMed

Sarkar, Sounak; Li, Shan; Wayland, Bradford B

2011-04-18

Tetramesityl porphinato rhodium(III) methoxide ((TMP)Rh-OCH(3)) binds with methanol in benzene to form a 1:1 methanol complex ((TMP)Rh-OCH(3)(CH(3)OH)) (1). Dynamic processes are observed to occur for the rhodium(III) methoxide methanol complex (1) that involve both hydrogen and methanol exchange. Hydrogen exchange between coordinated methanol and methoxide through methanol in solution results in an interchange of the environments for the non-equivalent porphyrin faces that contain methoxide and methanol ligands. Interchange of the environments of the coordinated methanol and methoxide sites in 1 produces interchange of the inequivalent mesityl o-CH(3) groups, but methanol ligand exchange occurs on one face of the porphyrin and the mesityl o-CH(3) groups remain inequivalent. Rate constants for dynamic processes are evaluated by full line shape analysis for the (1)H NMR of the mesityl o-CH(3) and high field methyl resonances of coordinated methanol and methoxide groups in 1. The rate constant for interchange of the inequivalent porphyrin faces is associated with hydrogen exchange between 1 and methanol in solution and is observed to increase regularly with the increase in the mole fraction of methanol. The rate constant for methanol ligand exchange between 1 and the solution varies with the solution composition and fluctuates in a manner that parallels the change in the activation energy for methanol diffusion which is a consequence of solution non-ideality from hydrogen bonded clusters.

Cost effectiveness of three different release treatments of table mountain pine in a severely overstocked and pure stand

Treesearch

Amy L. Morgan; Wayne K. Clatterbuck

2013-01-01

Table Mountain pine (Pinus pungens Lamb.) (TMP) is a threatened species, endemic to the Southern Appalachian Mountains. This study focuses on the release of TMP stems in an overstocked and pure TMP stand on the Cherokee National Forest in eastern Tennessee. The objective of the case study was to produce a cost analysis/comparison of releasing young...

Dissemination of Trimethoprim-Sulfamethoxazole Drug Resistance Genes Associated with Class 1 and Class 2 Integrons Among Gram-Negative Bacteria from HIV Patients in South India.

PubMed

Ramesh Kumar, Marimuthu Ragavan; Arunagirinathan, Narasingam; Srivani, Seetharaman; Dhanasezhian, Aridoss; Vijaykanth, Nallusamy; Manikandan, Natesan; Balakrishnan, Sethuramalingam; Vignesh, Ramachandran; Balakrishnan, Pachamuthu; Solomon, Suniti; Solomon, Sunil S

2017-07-01

The antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX), is generally used for prophylaxis in HIV individuals to protect them from Pneumocystis jiroveci infection. Long-term use of TMP-SMX develops drug resistance among bacteria in HIV patients. The study was aimed to detect the TMP-SMX resistance genes among gram-negative bacteria from HIV patients. TMP-SMX-resistant isolates were detected by the Kirby-Bauer disc diffusion method. While TMP resistance genes such as dfrA1, dfrA5, dfrA7, and dfrA17 and SMX resistance genes such as sul1 and sul2 were detected by multiplex PCR, class 1 and class 2 integrons were detected by standard monoplex PCR. Of the 151 TMP-SMX-resistant bacterial isolates, 3 were positive for sul1 alone, 48 for sul2 alone, 11 for dfrA7 alone, 21 for sul1 and sul2, 1 for sul1 and dfrA7, 23 for sul2 and dfrA7, 2 for sul2 and dfrA5, 41 for sul1, sul2, and dfrA7, and 1 for sul2, dfrA5, and dfrA7. Of 60 TMP-SMX-resistant isolates positive for integrons, 44 had class 1 and 16 had class 2 integrons. It was found that the prevalence of sul genes (n = 202; p < 0.001) was higher compared with dfr genes (n = 80; p < 0.001), and 87.4% (n = 132; p < 0.001) of TMP-SMX-resistant isolates also were positive for β-lactamase production. This type of study is reported for the first time from HIV patients in India. Therefore, this study indicates that dissemination of TMP-SMX resistance genes and class 1 and class 2 integrons along with β-lactamase production among gram-negative bacteria in HIV patients will certainly make their treatment to bacterial infections more complicated in clinical settings.

Multicenter study of trimethoprim/sulfamethoxazole-related hepatotoxicity: incidence and associated factors among HIV-infected patients treated for Pneumocystis jirovecii pneumonia.

PubMed

Yang, Jen-Jia; Huang, Chung-Hao; Liu, Chun-Eng; Tang, Hung-Jen; Yang, Chia-Jui; Lee, Yi-Chien; Lee, Kuan-Yeh; Tsai, Mao-Song; Lin, Shu-Wen; Chen, Yen-Hsu; Lu, Po-Liang; Hung, Chien-Ching

2014-01-01

The incidence of hepatotoxicity related to trimethoprim/sulfamethoxazole (TMP/SMX) administered at a therapeutic dose may vary among study populations of different ethnicities and hepatotoxic metabolites of TMP/SMX may be decreased by drug-drug interaction with fluconazole. We aimed to investigate the incidence of hepatotoxicity and the role of concomitant use of fluconazole in HIV-infected patients receiving TMP/SMX for Pneumocystis jirovecii pneumonia. We reviewed medical records to collect clinical characteristics and laboratory data of HIV-infected patients who received TMP/SMX for treatment of P. jirovecii pneumonia at 6 hospitals around Taiwan between September 2009 and February 2013. Hepatotoxicity was defined as 2-fold or greater increase of aminotransferase or total bilirubin level from baselines. Roussel UCLAF Causality Assessment Method (RUCAM) was used to analyze the causality of drug-induced liver injuries. NAT1 and NAT2 acetylator types were determined with the use of polymerase-chain-reaction (PCR) restriction fragment length polymorphism to differentiate common single-nucleotide polymorphisms (SNPs) predictive of the acetylator phenotypes in a subgroup of patients. During the study period, 286 courses of TMP/SMX treatment administered to 284 patients were analyzed. One hundred and fifty-two patients (53.1%) developed hepatotoxicity, and TMP/SMX was considered causative in 47 (16.4%) who had a RUCAM score of 6 or greater. In multivariate analysis, concomitant use of fluconazole for candidiasis was the only factor associated with reduced risk for hepatotoxicity (adjusted odds ratio, 0.372; 95% confidence interval, 0.145-0.957), while serostatus of hepatitis B or C virus, NAT1 and NAT2 acetylator types, or receipt of combination antiretroviral therapy was not. The incidence of hepatotoxicity decreased with an increasing daily dose of fluconazole up to 4.0 mg/kg. We conclude that the incidence of TMP/SMX-related hepatotoxicity was 16.4% in HIV-infected Taiwanese patients who received TMP/SMX for pneumocystosis. Concomitant use of fluconazole was associated with decreased risk for TMP/SMX-related hepatotoxicity.

Study of thermomechanical treatment on mechanical-induced phase transformation of NiTi and TiNiCu wires.

PubMed

Seyyed Aghamiri, S M; Nili Ahmadabadi, M; Shahmir, H; Naghdi, F; Raygan, Sh

2013-05-01

The nickel-titanium shape memory alloys have been used in orthodontic application due to their unique properties like superelasticity and biocompatibility. The phase transformation behavior of these alloys can be changed by alloying elements and thermomechanical processing conditions. In this study, two types of NiTi and TiNiCu wires of 0.4mm diameter were produced via thermomechanical treatments with final step of 20% cold drawing followed by annealing at different temperatures of 300 and 400 °C for varying times of 10, 30 and 60 min. The processed wires were characterized by oral cavity configuration three point bending (OCTPB) test at 37 °C to specify the mechanical transformation features. Also, differential scanning calorimetry (DSC) was used to analyze the thermal transformation temperatures of selected wires. The results showed the thermomechanical treatment at 300 °C for 30 min was the suitable process in terms of superelasticity and transformation temperatures for orthodontic application. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of thermomechanical processing on biomechanical compatibility and electrochemical behavior of new near beta alloy, Ti-20.6Nb-13.6Zr-0.5V

PubMed Central

Mohammed, Mohsin Talib; Khan, Zahid A; Manivasagam, Geetha; Siddiquee, Arshad N

2015-01-01

This paper presents the results for the effect of different methods of thermomechanical processing on the mechanical properties and electrochemical behavior of metastable β alloy Ti-20.6Nb-13.6Zr-0.5V (TNZV). The thermomechanical processing included hot working, solution heat treatments at different temperatures, and cooling rates in addition to aging. The thermomechanical processing conditions used in the study resulted in attainment of a wide range of microstructures with varying spatial distributions and morphologies of elongated/equiaxed α, β phases, or martensite, as a result of which several tensile properties were achieved. Aging treatment led to an increase in hardness, elastic modulus, and tensile strength and a decrease in ductility (elongation). Electrochemical tests indicated that the TNZV alloy undergoes spontaneous passivation due to spontaneous formation of an oxide film in the environment of the human body. Because the air-cooled samples possessed high hardness and also a fine grain size, they showed a lower corrosion rate than the samples treated under other conditions. PMID:26491324

Experimental investigations on the state of the friction-welded joint zone in steel hybrid components after process-relevant thermo-mechanical loadings

NASA Astrophysics Data System (ADS)

Behrens, B.-A.; Bouguecha, A.; Vucetic, M.; Peshekhodov, I.; Matthias, T.; Kolbasnikov, N.; Sokolov, S.; Ganin, S.

2016-10-01

As a part of the newly established Collaborative Research Center 1153 (SFB 1153) "Process chain for the manufacturing of hybrid high-performance components by tailored forming" at the Leibniz Universität Hannover, the Institute of Forming Technology and Machines (IFUM) examines the influence of thermo-mechanical stresses on the reduced Young's modulus as well as the hardness of hybrid (steel-steel compound) joined semi-finished products. Currently the expertise in the production of bulk metal formed parts is limited to mono-materials. For manufacturing parts of hybrid materials and also for the methods of the new process routes, practical experience has to be gained. The subproject C1 within the collaborative research center 1153 with the short title "Failure Prediction" deals with the question, if the hybrid semi-finished products fulfill the thermo-mechanical demands or if they fail at the joining zone (JZ) during forging. For this purpose, stresses similar to those in the process were imposed on hybrid semi-finished products by torsion tests by using the thermo-mechanical test system Gleeble 3800. Afterwards, the specimens were examined metallographically and by nanoindentations with the help of a TriboIndenter TI950. Thus, first knowledge on the behaviour of thermo-mechanical stresses on the reduced Young's modulus and the hardness of hybrid joined semi-finished parts was gained.

Life threatening hyperkalemia and acidosis secondary to trimethoprim-sulfamethoxazole treatment.

PubMed

Margassery, S; Bastani, B

2001-01-01

We present a 77-year-old male with moderate chronic renal insufficiency from diabetic nephropathy who developed severe metabolic acidosis and life threatening hyperkalemia on treatment with regular dose of trimethoprim-sulfamethoxazole (TMP-SMZ) for urinary tract infection. The metabolic acidosis and hyperkalemia resolved upon appropriate medical intervention and discontinuation of TMP-SMZ. While hyperkalemia has commonly been reported with high dose of TMP-SMZ, severe metabolic acidosis is quite uncommon with regular dose TMP-SMZ. We emphasize that patients with renal tubular acidosis (RTA), renal insufficiency, aldosterone deficiency, old age with reduced renal mass and function, and angiotensin converting enzyme (ACE)-inhibitor therapy are at high risk of developing these severe and potentially life threatening complications.

Effect of UVA/LED/TiO2 photocatalysis treated sulfamethoxazole and trimethoprim containing wastewater on antibiotic resistance development in sequencing batch reactors.

PubMed

Cai, Qinqing; Hu, Jiangyong

2018-04-24

Controlling of antibiotics is the crucial step for preventing antibiotic resistance genes (ARGs) dissemination; UV photocatalysis has been identified as a promising pre-treatment technology for antibiotics removal. However, information about the effects of intermediates present in the treated antibiotics wastewater on the downstream biological treatment processes or ARGs development is very limited. In the present study, continuous UVA/LED/TiO 2 photocatalysis removed more than 90% of 100 ppb sulfamethoxazole (SMX)/trimethoprim (TMP), the treated wastewater was fed into SBR systems for over one year monitoring. Residual SMX/TMP (2-3 ppb) and intermediates present in the treated wastewater did not adversely affect SBR performance in terms of TOC and TN removal. SMX and TMP resistance genes (sulI, sulII, sulIII, dfrII, dfrV and dfr13) were also quantified in SBRs microbial consortia. Results suggested that continuous feeding of treated SMX/TMP containing wastewaters did not trigger any ARGs promotion during the one year operation. By stopping the input of 100 ppb SMX/TMP, abundance of sulII and dfrV genes were reduced by 83% and 100%, respectively. sulI gene was identified as the most persistence ARG, and controlling of 100 ppb SMX input did not achieve significant removal of sulI gene. A significant correlation between sulI gene and class 1 integrons was found at the level of p = 1.4E-10 (r = 0.94), and sulII gene positively correlated with the plasmid transfer efficiency (r = 2.442E-10, r = 0.87). Continuous input of 100 ppb SMX enhanced plasmid transfer efficiency in the SBR system, resulting in sulII gene abundance increasing more than 40 times. Copyright © 2018 Elsevier Ltd. All rights reserved.

Coordination polymer flexibility leads to polymorphism and enables a crystalline solid-vapour reaction: a multi-technique mechanistic study.

PubMed

Vitórica-Yrezábal, Iñigo J; Libri, Stefano; Loader, Jason R; Mínguez Espallargas, Guillermo; Hippler, Michael; Fletcher, Ashleigh J; Thompson, Stephen P; Warren, John E; Musumeci, Daniele; Ward, Michael D; Brammer, Lee

2015-06-08

Despite an absence of conventional porosity, the 1D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 ] (1; TMP=tetramethylpyrazine) can absorb small alcohols from the vapour phase, which insert into AgO bonds to yield coordination polymers [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 (ROH)2 ] (1-ROH; R=Me, Et, iPr). The reactions are reversible single-crystal-to-single-crystal transformations. Vapour-solid equilibria have been examined by gas-phase IR spectroscopy (K=5.68(9)×10(-5) (MeOH), 9.5(3)×10(-6) (EtOH), 6.14(5)×10(-5) (iPrOH) at 295 K, 1 bar). Thermal analyses (TGA, DSC) have enabled quantitative comparison of two-step reactions 1-ROH→1→2, in which 2 is the 2D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)2 ] formed by loss of TMP ligands exclusively from singly-bridging sites. Four polymorphic forms of 1 (1-A(LT) , 1-A(HT) , 1-B(LT) and 1-B(HT) ; HT=high temperature, LT=low temperature) have been identified crystallographically. In situ powder X-ray diffraction (PXRD) studies of the 1-ROH→1→2 transformations indicate the role of the HT polymorphs in these reactions. The structural relationship between polymorphs, involving changes in conformation of perfluoroalkyl chains and a change in orientation of entire polymers (A versus B forms), suggests a mechanism for the observed reactions and a pathway for guest transport within the fluorous layers. Consistent with this pathway, optical microscopy and AFM studies on single crystals of 1-MeOH/1-A(HT) show that cracks parallel to the layers of interdigitated perfluoroalkyl chains develop during the MeOH release/uptake process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of branched polymers from lipase-catalyzed trimethylolpropane copolymerizations.

PubMed

Kulshrestha, Ankur S; Gao, Wei; Fu, Hongyong; Gross, Richard A

2007-06-01

Lipase-catalyzed terpolymerizations were performed with the monomers trimethylolpropane (B3), 1,8-octanediol (B2), and adipic acid (A2). Polymerizations were performed in bulk, at 70 degrees C, for 42 h, using immobilized lipase B from Candida antartica (Novozyme-435) as a catalyst. To determine the substitution pattern of trimethylolpropane (TMP) in copolymers, model compounds with variable degrees of acetylation were synthesized. Inverse-gated 13C NMR spectra were recorded to first determine the chemical shift positions for mono-, di-, and trisubstituted TMP units and, subsequently, to determine substitution of TMP units along chains. Variation of TMP in the monomer feed gave copolymers with degrees of branching (DB) from 20% to 67%. In one example, a hyperbranched copolyester with 53 mol % TMP adipate units was formed in 80% yield, with Mw 14 100 (relative to polystyrene standards), Mw/Mn 5.3, and DB 36%. Thermal and crystalline properties of the copolyesters were studied by thermogravimetric analysis and differential scanning calorimetry.

Environmentally realistic concentrations of the antibiotic Trimethoprim affect haemocyte parameters but not antioxidant enzyme activities in the clam Ruditapes philippinarum.

PubMed

Matozzo, Valerio; De Notaris, Chiara; Finos, Livio; Filippini, Raffaella; Piovan, Anna

2015-11-01

Several biomarkers were measured to evaluate the effects of Trimethoprim (TMP; 300, 600 and 900 ng/L) in the clam Ruditapes philippinarum after exposure for 1, 3 and 7 days. The actual TMP concentrations were also measured in the experimental tanks. The total haemocyte count significantly increased in 7 day-exposed clams, whereas alterations in haemocyte volume were observed after 1 and 3 days of exposure. Haemocyte proliferation was increased significantly in animals exposed for 1 and 7 days, whereas haemocyte lysate lysozyme activity decreased significantly after 1 and 3 days. In addition, TMP significantly increased haemolymph lactate dehydrogenase activity after 3 and 7 days. Regarding antioxidant enzymes, only a significant time-dependent effect on CAT activity was recorded. This study demonstrated that environmentally realistic concentrations of TMP affect haemocyte parameters in clams, suggesting that haemocytes are a useful cellular model for the assessment of the impact of TMP on bivalves. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regulation Mechanism of Novel Thermomechanical Treatment on Microstructure and Properties in Al-Zn-Mg-Cu Alloy

NASA Astrophysics Data System (ADS)

Chen, Zhiguo; Ren, Jieke; Zhang, Jishuai; Chen, Jiqiang; Fang, Liang

2016-02-01

Scanning electron microscopy, transmission electron microscopy, tensile test, exfoliation corrosion test, and slow strain rate tensile test were applied to investigate the properties and microstructure of Al-Zn-Mg-Cu alloy processed by final thermomechanical treatment, retrogression reaging, and novel thermomechanical treatment (a combination of retrogression reaging with cold or warm rolling). The results indicate that in comparison with conventional heat treatment, the novel thermomechanical treatment reduces the stress corrosion susceptibility. A good combination of mechanical properties, stress corrosion resistance, and exfoliation corrosion resistance can be obtained by combining retrogression reaging with warm rolling. The mechanism of the novel thermomechanical treatment is the synergistic effect of composite microstructure such as grain morphology, dislocation substructures, as well as the morphology and distribution of primary phases and precipitations.

Design of a large magnetic-bearing turbomolecular pump for NET

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

Bernhardt, K.H.; Conrad, A.; Dinner, P.J.

1988-09-01

The feasibility of development of large vacuum components for operation in fusion machines have been investigated in the framework of the European Fusion Technology Programme. The requirements and the results of the feasibility study for the large turbomolecular pump units (TMP) are presented. Design parameters for single flow 50.000 l/s TMP and a double flow 15.000 and a 50.000 l/s TMP have been compared.

Development and validation of an HPLC method for simultaneous determination of trimethoprim and sulfamethoxazole in human plasma.

PubMed

Sayar, Esin; Sahin, Selma; Cevheroglu, Semsettin; Hincal, A Atilla

2010-09-01

The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) is used in the treatment of many common infections such as urinary, respiratory and gastrointestinal tract infections. The aim of this study was to determine TMP and SMX simultaneously in human plasma samples by high performance liquid chromatography (HPLC) using antipyrine as the internal standard. Separation of the compounds was achieved on a reverse-phase C8 column packed with 5 microm dimethyl octadecylsilyl bonded amorphous silica (4.6 mm x 250 mm) column using a mobile phase consisted of potassium hydrogen phosphate, acetonitrile, methanol and water adjusted to pH 6.2. The mobile phase was delivered at a flow rate of 1 mL min- and the effluent was monitored using Max plot technique at 25 derees C. Retention times were 5 min for TMP, 7 min for antipyrine and 9 min for SMX. Quantitation limits were 10 ng mL(-1) for TMP and 50 ng mL(-1) for SMX. Our findings indicated that the developed HPLC method was precise, accurate, specific and sensitive for simultaneous determination of TMP and SMX. Proposed HPLC method was successfully applied for the analysis of TMP and SMX in human plasma after oral administration of a co-trimoxazole tablet to human volunteers.

Effect of ultrasonic pre-treatment of thermomechanical pulp on hydrogen peroxide bleaching

NASA Astrophysics Data System (ADS)

Loranger, E.; Charles, A.; Daneault, C.

2012-12-01

Ultrasound pre-treatments of softwood TMP had been carried to evaluate its impact on the efficiency of hydrogen peroxide bleaching. The trials were performed after a factorial design of experiment using frequency, power and time as variables. The experiments were conducted in an ultrasonic bath and then bleached with hydrogen peroxide. Measurements such as brightness, L*A*B* color system coordinate, residual hydrogen peroxide and metal content were evaluated on bleached pulp. The results indicate that the effect of ultrasonic treatment on brightness was dependent on the ultrasound frequency used; the brightness increased slightly at 68 kHz and decreased at 40 and 170 kHz. These results were correlated to the ultrasound effect on the generation of transition metals (copper, iron and manganese) which are responsible for catalytic decomposition of hydrogen peroxide. The influence of metal interference was minimized by using a chelating agent such as diethylene triamine pentaacetic acid (DTPA). With the results obtained in this study we have identified a set of option conditions, e.g. 1000 W, 40 kHz, 1.5 % consistency and 0.2% addition of DTPA prior to the bleaching stage (after ultrasonic pre-treatment) who improve brightness by 2.5 %ISO.

Sorption of carbamazepine, 17α-ethinylestradiol, iopromide and trimethoprim to biomass involves interactions with exocellular polymeric substances.

PubMed

Khunjar, Wendell O; Love, Nancy G

2011-02-01

The sorption of carbamazepine (CBZ), iopromide (IOP), trimethoprim (TMP) and 17α-ethinylestradiol (EE2) was evaluated using four biomass types (pure ammonia oxidizing bacterial culture, two heterotrophic enrichment cultures with varying levels of oxygenase activity, and a full-scale nitrifying activated sludge (NAS) culture). CBZ and IOP did not sorb to the four biomass types. EE2 did not sorb to the pure culture but sorbed significantly to the heterotrophic cultures and NAS. TMP sorbed to the heterotrophic cultures and NAS, and was not evaluated for the pure culture. Three floc characteristics (hydrophobicity, median particle size, organic matter content) correlated moderately well with the EE2 organic matter sorption coefficient (KOM,EE2). Zeta potential did not correlate well with KOM,EE2 but did with KOM,TMP, indicating that TMP sorption is more influenced by electrostatic factors than EE2. Once divalent cation-linked exocellular polymeric substances (EPS) were removed from flocs, EE2 and TMP sorption to the non-EPS (cellular) fraction decreased by approximately 50%. The correlation between KOM,EE2 for the non-EPS cellular fraction deteriorated while the correlation between KOM,TMP improved. EE2 seemed to sorb more strongly to EPS protein whereas TMP sorbed equally to polysaccharide and protein EPS. Attempts to develop predictive models were not successful. Pharmaceuticals that sorbed to biomass samples underwent biodegradation whereas those that did not sorb were not biodegraded, suggesting a relationship between sorption and pharmaceutical biotransformation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Single- and multiple-dose pharmacokinetics of a novel tetramethylpyrazine reservoir-type transdermal patch versus tetramethylpyrazine phosphate oral tablets in healthy normal volunteers, and in vitro/in vivo correlation.

PubMed

Shen, Teng; Xu, Huinan; Weng, Weiyu; Zhang, Jianfang

2013-01-01

A novel reservoir-type transdermal system of 2,3,5,6-tetramethylpyrazine (TMP) was developed containing eucalyptus oil as a penetration enhancer. The single and multiple-dose pharmacokinetic profiles of TMP administrated by TMP transdermal patch were characterized in healthy volunteers using an in vivo, randomized, open-label, two-way crossover design. 2,3,5,6-Tetramethylpyrazine phosphate (TMPP) oral tablets were chosen as reference. Following single/multiple oral administration of 200/100 mg TMPP tablets, a TMP C(max) of 1284/613.5 ng/mL was observed within 0.75 h. Single/multiple applications of the TMP patch yielded mean C(max) of 309/325 ng/mL at a median T(max) of 5/4 h, with steady state achieved at second application. The mean C(min) of the patch was 131±30.38 ng/mL, contrasting to nearly zero for the tablet. Multiple applications of patch produced an accumulative effect over single application. At steady state 250 mg/20 cm(2) TMP patch given daily provided comparable exposure to 100 mg TMPP tablets three times daily (3753.91 versus 3563.67 ng·h/mL). TMP tablets and patch yielded similar steady-state plasma concentrations: C(av) (148.48±51.27, 156.41±40.31 ng/mL). The results demonstrated that TMP patch can achieve a therapeutic effect that is comparable to oral administration, exhibited prolonged and sustained plasma levels, fewer drug fluctuations, lower adverse effects, more convenience, and improved patient compliance. In-vitro permeation through human skin demonstrated zero-order kinetics with the flux of 364 µg/cm(2)/h. The predicted C(av) (163.9 ng/mL) was in agreement with the observed C(av) (156.4 ng/mL).

Synthesis of phospholyl-bridged heterobimetallic ruthenium hydrides in combination with zirconium and ytterbium and the crystal structure of (THF){sub 2}Yb[{mu}({eta}{sup 5}, {eta}{sup 1})-C{sub 4}Me{sub 4}P]{sub 2 }Ru(H){sub 2}(Ph{sub 3}P){sub 2}

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

Desmurs, P.; Visseaux, M.; Baudry, D.

1996-10-01

Heterobimetallic zirconium-ruthenium and ytterbium-ruthenium dihydrides, having bridging phospholyl ligands, have been obtained for the first time. Reaction of bis({eta}{sup 5}-tetramethylphospholyl)dichlorozirconium [(TMP){sub 2}ZrCl{sub 2}] with RuH{sub 4}(PPh{sub 3}){sub 3} gave the zirconium-ruthenium heterobimetallic Cl{sub 2}Zr[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H){sub 2} (PPh{sub 3}){sub 2}. This compound was transformed into the hydridochloride Cl{sub 2}Zr[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H)(Cl)( PPh{sub 3}){sub 2} by the action of CCl{sub 4}. Similarly, reaction of [(TMP){sub 2}Yb] with RuH{sub 4}(PPh{sub 3}){sub 3} afforded (THF){sub 2}Yb[{mu}({eta}{sup 5}, meta{sup 1})-TMP]{sub 2}Ru(H){sub 2}(PPh{sub 3}){sub 2}. The structure of this compound, which has been determined by X-ray crystallography, confirms the trans configuration of themore » dihydride deduced previously from NMR data. Attempts to isolate products from the reaction of [(TMP){sub 2}UCl{sub 2}] or [(TMP){sub 2}U(BH{sub 4}){sub 2}] with RuH{sub 4}(PPh{sub 3}){sub 3} were unsuccessful, but NMR data show the formation of both heterobimetallic trans- and cis-ruthenium dihydride-uranium compounds X{sub 2}U[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H){sub 2}(P Ph{sub 3}){sub 2} (X = BH{sub 4}, Cl) in solution. 19 refs., 1 fig., 2 tabs.« less

Carbon-carbon bond activation of 2,2,6,6-tetramethyl-piperidine-1-oxyl by a Rh(II) metalloradical: a combined experimental and theoretical study.

PubMed

Chan, Kin Shing; Li, Xin Zhu; Dzik, Wojciech I; de Bruin, Bas

2008-02-13

Competitive major carbon-carbon bond activation (CCA) and minor carbon-hydrogen bond activation (CHA) channels are identified in the reaction between rhodium(II) meso-tetramesitylporphyrin [Rh(II)(tmp)] (1) and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) (2). The CCA and CHA pathways lead to formation of [Rh(III)(tmp)Me] (3) and [Rh(III)(tmp)H] (5), respectively. In the presence of excess TEMPO, [Rh(II)(tmp)] is regenerated from [Rh(III)(tmp)H] with formation of 2,2,6,6-tetramethyl-piperidine-1-ol (TEMPOH) (4) via a subsequent hydrogen atom abstraction pathway. The yield of the CCA product [Rh(III)(tmp)Me] increased with higher temperature at the cost of the CHA product TEMPOH in the temperature range 50-80 degrees C. Both the CCA and CHA pathways follow second-order kinetics. The mechanism of the TEMPO carbon-carbon bond activation was studied by means of kinetic investigations and DFT calculations. Broken symmetry, unrestricted b3-lyp calculations along the open-shell singlet surface reveal a low-energy transition state (TS1) for direct TEMPO methyl radical abstraction by the Rh(II) radical (SH2 type mechanism). An alternative ionic pathway, with a somewhat higher barrier, was identified along the closed-shell singlet surface. This ionic pathway proceeds in two sequential steps: Electron transfer from TEMPO to [Rh(II)(por)] producing the [TEMPO]+ [RhI(por)]- cation-anion pair, followed by net CH3+ transfer from TEMPO+ to Rh(I) with formation of [Rh(III)(por)Me] and (DMPO-like) 2,2,6-trimethyl-2,3,4,5-tetrahydro-1-pyridiniumolate. The transition state for this process (TS2) is best described as an SN2-like nucleophilic substitution involving attack of the d(z)2 orbital of [Rh(I)(por)]- at one of the C(Me)-C(ring) sigma* orbitals of [TEMPO]+. Although the calculated barrier of the open-shell radical pathway is somewhat lower than the barrier for the ionic pathway, R-DFT and U-DFT are not likely comparatively accurate enough to reliably distinguish between these possible pathways. Both the radical (SH2) and the ionic (SN2) pathway have barriers which are low enough to explain the experimental kinetic data.

Modeling of Microstructure Evolution During the Thermomechanical Processing of Titanium Alloys (Preprint)

DTIC Science & Technology

2008-07-01

Tailoring the Properties of Aluminum and Titanium Alloys", Deformation, Processing, and Structure , G. Krauss, ed., ASM International, Materials Park, OH...1984, pp. 279-354. 51. G.W. Kuhlman, "A Critical Appraisal of Thermomechanical Processing of Structural Titanium Alloys", Microstructure/ Property ... titanium alloys is heavily dependent on the allotropic transformation from a hexagonal-close-packed crystal structure (denoted as alpha phase) found at

An evaluation of hyperkalemia and serum creatinine elevation associated with different dosage levels of outpatient trimethoprim-sulfamethoxazole with and without concomitant medications.

PubMed

Gentry, Chris A; Nguyen, Ann T

2013-12-01

Adverse events associated with high-dose trimethoprim-sulfamethoxazole (TMP-SMX) for outpatient infections, particularly those likely caused by community-acquired methicillin-resistant Staphylococcus aureus, have not been adequately characterized. Describe hyperkalemia and acute renal injury associated with high-dose TMP-SMX. An electronic medical record database retrospective study was conducted of outpatients receiving high-dose or low-dose TMP-SMX, comparing the incidences of hyperkalemia and acute renal injury. Of 6162 patients, more developed hyperkalemia (3.06% vs 1.05%, P < .0001) or acute renal injury (1.99% vs 0.700%, P = .0001) in the high-dose TMP-SMX group. Variables independently associated with hyperkalemia included age >58 years (odds ratio [OR] = 3.44; 95% CI = 1.86-7.0; P < .0001), concomitant receipt of an NSAID (OR = 1.71; 95% CI = 1.02-2.79; P = .044) or an ACE inhibitor (OR = 3.27; 95% CI = 2.06-5.14; P < .0001), high-dose TMP-SMX prescribed (OR = 2.92; 95% CI = 1.85-4.60; P < .0001), and baseline elevated serum creatinine (OR = 45.1; 95% CI = 21.7-93.2; P < .0001). Variables independently associated with acute renal injury included concomitant receipt of an ACE inhibitor (OR = 2.36; 95% CI = 1.01-5.24; P = .048) or a potassium supplement (OR = 4.10; 95% CI = 1.45-10.1; P = .010), high-dose TMP-SMX prescribed (OR = 3.70; 95% CI = 1.70-8.12; P = .0012), and baseline elevated serum creatinine (OR = 2110; 95% CI = 724-7980; P < .0001). Serum creatinine and potassium concentrations should be monitored in outpatients receiving high-dose TMP-SMX.

Virgin coconut oil protects against liver damage in albino rats challenged with the anti-folate combination, trimethoprim-sulfamethoxazole.

PubMed

Otuechere, Chiagoziem A; Madarikan, Gbemisola; Simisola, Tinuala; Bankole, Olubukola; Osho, Adeleke

2014-05-01

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad-spectrum antibiotic. However, its use is associated with toxic reactions. Virgin coconut oil (VCO), derived from coconut, has been widely used throughout history for its medicinal value. The aim of this study was to investigate the beneficial actions of VCO against TMP-SMX-induced alterations in serum biochemical end points. Twenty rats were divided into four groups. Group 1 (control) received no drug, whereas group 2 received TMP-SMX (8/40 mg/kg) twice daily for 7 days. Group 3 was administered coconut oil at a dose of 600 mg/kg body weight per day. The last group was treated with TMP-SMX (8/40 mg/kg) and coconut oil (600 mg/kg) simultaneously. Blood samples were collected from all groups on the 8th day of the experiment for measurement of serum biochemical parameters. Organ weights and coefficients were also evaluated. TMP-SMX caused a significant (p<0.05) increase in the levels of serum total bilirubin, lactate dehydrogenase, and alkaline phosphatase by 192%, 67%, and 41%, respectively, relative to controls. This was followed by a significant reduction in triglyceride and relative kidney weight by 40% and 7%, respectively. There were no significant differences (p>0.05) in the activities of serum aminotransferases, total acid phosphatase, γ-glutamyl transferase, uric acid, cholesterol, albumin, and urea levels. Supplementation of VCO ameliorated TMP-SMX-induced effects by restoring the levels of total bilirubin, alkaline phospahatase, and lactate dehydrogenase. The results of this study demonstrate that the active components of coconut oil had protective effects against the toxic effects induced by TMP-SMX administration, especially in the liver of rats.

Trimethoprim/Sulfamethoxazole-Induced Severe Lactic Acidosis: A Case Report and Review of the Literature.

PubMed

Bulathsinghala, Marie; Keefer, Kimberly; Van de Louw, Andry

2016-04-01

Propylene glycol (PG) is used as a solvent in numerous medications, including trimethoprim/sulfamethoxazole (TMP/SMX) and lorazepam, and is metabolized in the liver to lactic acid. Cases of lactic acidosis related to PG toxicity have been described and always involved large doses of benzodiazepines and PG. We present the first case of severe lactic acidosis after a 3-day course of TMP/SMX alone, involving allegedly safe amounts of PG.A 31-year-old female with neurofibromatosis and pilocytic astrocytoma, receiving temozolomide and steroids, was admitted to the intensive care unit for pneumonia and acute respiratory failure requiring intubation. Her initial hemodynamic and acid-base statuses were normal. She was treated with intravenous TMP/SMX for possible Pneumocystis jirovecii pneumonia and was successfully extubated on day 2. On day 3, she developed tachypnea and arterial blood gas analysis revealed a severe metabolic acidosis (pH 7.2, PCO2 19 mm Hg, bicarbonates 8 mEq/L) with anion gap of 25 mEq/L and lactate of 12.1 mmol/L. TMP/SMX was discontinued and the lactate decreased to 2.9 mmol/L within 24 hours while her plasma bicarbonates normalized, without additional intervention. The patient never developed hypotension or severe hypoxia, and her renal and liver functions were normal. No other cause for lactic acidosis was identified and it resolved after TMP/SMX cessation alone, suggesting PG toxicity.Although PG-related lactic acidosis is well recognized after large doses of lorazepam, clinicians should bear in mind that TMP/SMX contains PG as well and should suspect PG toxicity in patients developing unexplained metabolic acidosis while receiving TMP/SMX.

Tertiary treatment of a municipal wastewater toward pharmaceuticals removal by chemical and electrochemical advanced oxidation processes.

PubMed

Moreira, Francisca C; Soler, J; Alpendurada, M F; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

2016-11-15

This study focuses on the degradation of pharmaceuticals from a municipal wastewater after secondary treatment by applying various advanced oxidation processes (AOPs) and electrochemical AOPs (EAOPs) like UVC, H 2 O 2 /UVC, anodic oxidation (AO), AO with electrogenerated H 2 O 2 (AO-H 2 O 2 ), AO-H 2 O 2 /UVC and photoelectro-Fenton (PEF) using either UVC radiation (PEF-UVC) or UVA radiation (PEF-UVA). The municipal wastewater after secondary treatment was spiked with 5.0 mg L -1 of trimethoprim (TMP) antibiotic. The efficiency of processes to remove TMP followed the order UVC < AO-H 2 O 2  < PEF-UVA < AO ≈ PEF-UVC < AO-H 2 O 2 /UVC < PEF-UVA (pH = 2.8) < H 2 O 2 /UVC ≈ PEF-UVC (pH = 2.8), using neutral pH, except when identified. While the UVC radiation alone led to a very low TMP removal, the H 2 O 2 /UVC process promoted a very high TMP degradation due to the production of hydroxyl radicals (OH) by H 2 O 2 cleavage. In the AO-H 2 O 2 /UVC process, the electrogeneration of H 2 O 2 can avoid the risks associated with the transportation, storage and manipulation of this oxidant and, furthermore, OH at the anode surface are also formed. Nevertheless, low contents of H 2 O 2 were detected mainly at the beginning of the reaction, leading to a lower initial reaction rate when compared with the H 2 O 2 /UVC system. In the PEF-UVC, the addition of iron at neutral pH led to the visible formation of insoluble iron oxides that can filter the light. At pH 2.8, the iron remained dissolved, thereby promoting the Fenton's reaction and increasing the organics removal. The UVA-driven processes showed limited efficiency when compared with those using UVC light. For all processes with H 2 O 2 electrogeneration, the active chlorine species can be scavenged by the H 2 O 2 , diminishing the efficiency of the processes. This can explain the lower efficiency of AO-H 2 O 2 when compared with AO. Moreover, the degradation of the MWWTP effluent spiked with 18 pharmaceuticals in μg L -1 during AO process was assessed as well as the influence of the following operational variables on the process efficiency: (i) H 2 O 2 concentration on H 2 O 2 /UVC, (ii) current density on AO, AO-H 2 O 2 , AO-H 2 O 2 /UVC, PEF-UVC and PEF-UVA, and (iii) pH on PEF-UVA. Copyright © 2016 Elsevier Ltd. All rights reserved.

A hybrid stochastic model of folate-mediated one-carbon metabolism: Effect of the common C677T MTHFR variant on de novo thymidylate biosynthesis.

PubMed

Misselbeck, Karla; Marchetti, Luca; Field, Martha S; Scotti, Marco; Priami, Corrado; Stover, Patrick J

2017-04-11

Folate-mediated one-carbon metabolism (FOCM) is an interconnected network of metabolic pathways, including those required for the de novo synthesis of dTMP and purine nucleotides and for remethylation of homocysteine to methionine. Mouse models of folate-responsive neural tube defects (NTDs) indicate that impaired de novo thymidylate (dTMP) synthesis through changes in SHMT expression is causative in folate-responsive NTDs. We have created a hybrid computational model comprised of ordinary differential equations and stochastic simulation. We investigated whether the de novo dTMP synthesis pathway was sensitive to perturbations in FOCM that are known to be associated with human NTDs. This computational model shows that de novo dTMP synthesis is highly sensitive to the common MTHFR C677T polymorphism and that the effect of the polymorphism on FOCM is greater in folate deficiency. Computational simulations indicate that the MTHFR C677T polymorphism and folate deficiency interact to increase the stochastic behavior of the FOCM network, with the greatest instability observed for reactions catalyzed by serine hydroxymethyltransferase (SHMT). Furthermore, we show that de novo dTMP synthesis does not occur in the cytosol at rates sufficient for DNA replication, supporting empirical data indicating that impaired nuclear de novo dTMP synthesis results in uracil misincorporation into DNA.

Gas-phase ion-molecule reactions for the identification of the sulfone functionality in protonated analytes in a linear quadrupole ion trap mass spectrometer.

PubMed

Tang, Weijuan; Sheng, Huaming; Kong, John Y; Yerabolu, Ravikiran; Zhu, Hanyu; Max, Joann; Zhang, Minli; Kenttämaa, Hilkka I

2016-06-30

The oxidation of sulfur atoms is an important biotransformation pathway for many sulfur-containing drugs. In order to rapidly identify the sulfone functionality in drug metabolites, a tandem mass spectrometric method based on ion-molecule reactions was developed. A phosphorus-containing reagent, trimethyl phosphite (TMP), was allowed to react with protonated analytes with various functionalities in a linear quadrupole ion trap mass spectrometer. The reaction products and reaction efficiencies were measured. Only protonated sulfone model compounds were found to react with TMP to form a characteristic [TMP adduct-MeOH] product ion. All other protonated compounds investigated, with functionalities such as sulfoxide, N-oxide, hydroxylamino, keto, carboxylic acid, and aliphatic and aromatic amino, only react with TMP via proton transfer and/or addition. The specificity of the reaction was further demonstrated by using a sulfoxide-containing anti-inflammatory drug, sulindac, as well as its metabolite sulindac sulfone. A method based on functional group-selective ion-molecule reactions in a linear quadrupole ion trap mass spectrometer has been demonstrated for the identification of the sulfone functionality in protonated analytes. A characteristic [TMP adduct-MeOH] product ion was only formed for the protonated sulfone analytes. The applicability of the TMP reagent in identifying sulfone functionalities in drug metabolites was also demonstrated. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Trans-Metal-Trapping Meets Frustrated-Lewis-Pair Chemistry: Ga(CH2SiMe3)3-Induced C–H Functionalizations

PubMed Central

2017-01-01

Merging two topical themes in main-group chemistry, namely, cooperative bimetallics and frustrated-Lewis-pair (FLP) activity, this Forum Article focuses on the cooperativity-induced outcomes observed when the tris(alkyl)gallium compound GaR3 (R = CH2SiMe3) is paired with the lithium amide LiTMP (TMP = 2,2,6,6-tetramethylpiperidide) or the sterically hindered N-heterocyclic carbene (NHC) 1,3-bis(tert-butyl)imidazol-2-ylidene (ItBu). When some previously published work are drawn together with new results, unique tandem reactivities are presented that are driven by the steric mismatch between the individual reagents of these multicomponent reagents. Thus, the LiTMP/GaR3 combination, which on its own fails to form a cocomplex, functions as a highly regioselective base (LiTMP)/trap (GaR3) partnership for the metalation of N-heterocycles such as diazines, 1,3-benzoazoles, and 2-picolines in a trans-metal-trapping (TMT) process that stabilizes the emerging sensitive carbanions. Taking advantage of related steric incompatibility, a novel monometallic FLP system pairing GaR3 with ItBu has been developed for the activation of carbonyl compounds (via C=O insertion) and other molecules with acidic hydrogen atoms such as phenol and phenylacetylene. Shedding new light on how these non-cocomplexing partnerships operate and showcasing the potential of gallium reagents to engage in metalation reactions or FLP activations, areas where the use of this group 13 metal is scant, this Forum Article aims to stimulate more interest and activity toward the advancement of organogallium chemistry. PMID:28485929

Distribution of sulfamonomethoxine and trimethoprim in egg yolk and white.

PubMed

Bilandžić, Nina; Božić, Đurđica; Kolanović, Božica Solomun; Varenina, Ivana; Cvetnić, Luka; Cvetnić, Željko

2015-07-01

The distribution of sulfamonomethoxine (SMM) and trimethoprim (TMP) in egg yolk and white was measured during and after administration of a SMM/TMP combination in laying hens in doses of 8 g l(-)(1) and 12 g l(-)(1) in drinking water for 7 days. The SMM concentration reached maximal levels on day 2 of the post-treatment period for both doses (μg kg(-)(1)): 5920 and 9453 in yolk; 4831 and 6050 in white, in doses 1 and 2, respectively. Significant differences in the SMM and TMP concentrations between yolk and white in post treatment period were found. SMM dropped below the LOD (1.9 μg kg(-1)) in yolk after day 16 and 19 for doses 1 and 2. TMP reached maximal levels on day 3 after drug administration for doses 1 and 2 (μg kg(-)(1)): 6521 and 7329 in yolk, 1370 and 1539 in white. TMP residues were measured above LOD (0.3 μg kg(-)(1)) in yolk for both doses on day 37 post-treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Viscoelastic properties of chalcogenide glasses and the simulation of their molding processes

NASA Astrophysics Data System (ADS)

Liu, Weiguo; Shen, Ping; Jin, Na

In order to simulate the precision molding process, the viscoelastic properties of chalcogenide glasses under high temperatures were investigated. Thermomechanical analysis were performed to measure and analysis the thermomechanical properties of chalcogenide glasses. The creep responses of the glasses at different temperatures were obtained. Finite element analysis was applied for the simulation of the molding processes. The simulation results were in consistence with previously reported experiment results. Stress concentration and evolution during the molding processes was also described with the simulation results.

Enhancing the ABAQUS Thermomechanics Code to Simulate Steady and Transient Fuel Rod Behavior

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

R. L. Williamson; D. A. Knoll

2009-09-01

A powerful multidimensional fuels performance capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. Enhanced capabilities are described, including: UO2 temperature and burnup dependent thermal properties, solid and gaseous fission product swelling, fuel densification, fission gas release, cladding thermal and irradiation creep, cladding irradiation growth , gap heat transfer, and gap/plenum gas behavior during irradiation. The various modeling capabilities are demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multi-pellet fuel rod, during both steady and transient operation. Computational results demonstrate the importancemore » of a multidimensional fully-coupled thermomechanics treatment. Interestingly, many of the inherent deficiencies in existing fuel performance codes (e.g., 1D thermomechanics, loose thermo-mechanical coupling, separate steady and transient analysis, cumbersome pre- and post-processing) are, in fact, ABAQUS strengths.« less

An Escherichia coli strain, PGB01, isolated from feral pigeon Faeces, thermally fit to survive in pigeon, shows high level resistance to trimethoprim.

PubMed

Kumar, Arvind; Tiwary, Bipransh Kumar; Kachhap, Sangita; Nanda, Ashis Kumar; Chakraborty, Ranadhir

2015-01-01

In this study, of the hundred Escherichia coli strains isolated from feral Pigeon faeces, eighty five strains were resistant to one or more antibiotics and fifteen sensitive to all the antibiotics tested. The only strain (among all antibiotic-resistant E. coli isolates) that possessed class 1 integron was PGB01. The dihydrofolate reductase gene of the said integron was cloned, sequenced and expressed in E. coli JM109. Since PGB01 was native to pigeon's gut, we have compared the growth of PGB01 at two different temperatures, 42°C (normal body temperature of pigeon) and 37°C (optimal growth temperature of E. coli; also the human body temperature), with E. coli K12. It was found that PGB01 grew better than the laboratory strain E. coli K12 at 37°C as well as at 42°C. In the thermal fitness assay, it was observed that the cells of PGB01 were better adapted to 42°C, resembling the average body temperature of pigeon. The strain PGB01 also sustained more microwave mediated thermal stress than E. coli K12 cells. The NMR spectra of the whole cells of PGB01 varied from E. coli K12 in several spectral peaks relating some metabolic adaptation to thermotolerance. On elevating the growth temperature from 37°C to 42°C, susceptibility to kanamycin (both strains were sensitive to it) of E. coli K12 was increased, but in case of PGB01 no change in susceptibility took place. We have also attempted to reveal the basis of trimethoprim resistance phenotype conferred by the dfrA7 gene homologue of PGB01. Molecular Dynamics (MD) simulation study of docked complexes, PGB01-DfrA7 and E. coli TMP-sensitive-Dfr with trimethoprim (TMP) showed loss of some of the hydrogen and hydrophobic interaction between TMP and mutated residues in PGB01-DfrA7-TMP complex compared to TMP-sensitive-Dfr-TMP complex. This loss of interaction entails decrease in affinity of TMP for PGB01-DfrA7 compared to TMP-sensitive-Dfr.

United States Air Force Research Initiation Program for 1987. Volume 3

DTIC Science & Technology

1989-04-01

Influence of Microstructural Variations Dr. Ravinder Diwan on the Thermomechanical Processing in Dynamic Material Modeling of Titanium Aluminides , 760,7MG...7MG-077 INFLUENCE OF MICROSTRUCTURAL VARIATIONS ON THE THERMOMECHANICAL PROCESSING IN DYNAMIC MATERIAL MODELING OF TITANIUM ALUMINIDES MARCH 15, 1989...provided on this project. Final Report Submitted: March 15, 1989. 75-1 ABSTRACT Titanium aluminides with strong thermodynamically stable intermetallic phases

Solar photo-Fenton process on the abatement of antibiotics at a pilot scale: Degradation kinetics, ecotoxicity and phytotoxicity assessment and removal of antibiotic resistant enterococci.

PubMed

Michael, I; Hapeshi, E; Michael, C; Varela, A R; Kyriakou, S; Manaia, C M; Fatta-Kassinos, D

2012-11-01

This work investigated the application of a solar driven advanced oxidation process (solar photo-Fenton), for the degradation of antibiotics at low concentration level (μg L(-1)) in secondary treated domestic effluents at a pilot-scale. The examined antibiotics were ofloxacin (OFX) and trimethoprim (TMP). A compound parabolic collector (CPC) pilot plant was used for the photocatalytic experiments. The process was mainly evaluated by a fast and reliable analytical method based on a UPLC-MS/MS system. Solar photo-Fenton process using low iron and hydrogen peroxide doses ([Fe(2+)](0) = 5 mg L(-1); [H(2)O(2)](0) = 75 mg L(-1)) was proved to be an efficient method for the elimination of these compounds with relatively high degradation rates. The photocatalytic degradation of OFX and TMP with the solar photo-Fenton process followed apparent first-order kinetics. A modification of the first-order kinetic expression was proposed and has been successfully used to explain the degradation kinetics of the compounds during the solar photo-Fenton treatment. The results demonstrated the capacity of the applied advanced process to reduce the initial wastewater toxicity against the examined plant species (Sorghum saccharatum, Lepidium sativum, Sinapis alba) and the water flea Daphnia magna. The phytotoxicity of the treated samples, expressed as root growth inhibition, was higher compared to that observed on the inhibition of seed germination. Enterococci, including those resistant to OFX and TMP, were completely eliminated at the end of the treatment. The total cost of the full scale unit for the treatment of 150 m(3) day(-1) of secondary wastewater effluent was found to be 0.85 € m(-3). Copyright © 2012 Elsevier Ltd. All rights reserved.

Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan.

PubMed

Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

2016-09-13

Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide.

Thermomechanical controls on magma supply and volcanic deformation: application to Aira caldera, Japan

PubMed Central

Hickey, James; Gottsmann, Joachim; Nakamichi, Haruhisa; Iguchi, Masato

2016-01-01

Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show how spatio-temporal deformation and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption. Magma storage conditions coincide with estimates for the caldera-forming reservoir ~29,000 years ago, and the inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic deformation worldwide. PMID:27619897

A 1D thermomechanical network transition constitutive model coupled with multiple structural relaxation for shape memory polymers

NASA Astrophysics Data System (ADS)

Zeng, Hao; Xie, Zhimin; Gu, Jianping; Sun, Huiyu

2018-03-01

A new thermomechanical network transition constitutive model is proposed in the study to describe the viscoelastic behavior of shape memory polymers (SMPs). Based on the microstructure of semi-crystalline SMPs, a new simplified transformation equation is proposed to describe the transform of transient networks. And the generalized fractional Maxwell model is introduced in the paper to estimate the temperature-dependent storage modulus. In addition, a neo-KAHR theory with multiple discrete relaxation processes is put forward to study the structural relaxation of the nonlinear thermal strain in cooling/heating processes. The evolution equations of the time- and temperature-dependent stress and strain response are developed. In the model, the thermodynamical and mechanical characteristics of SMPs in the typical thermomechanical cycle are described clearly and the irreversible deformation is studied in detail. Finally, the typical thermomechanical cycles are simulated using the present constitutive model, and the simulation results agree well with the experimental results.

Supramolecular Assembly of Uridine Monophosphate (UMP) and Thymidine Monophosphate (TMP) with a Dinuclear Copper(II) Receptor.

PubMed

Rhaman, Md Mhahabubur; Powell, Douglas R; Hossain, Md Alamgir

2017-11-30

Understanding the intermolecular interactions between nucleotides and artificial receptors is crucial to understanding the role of nucleic acids in living systems. However, direct structural evidence showing precise interactions and bonding features of a nucleoside monophosphate (NMP) with a macrocycle-based synthetic molecule has not been provided so far. Herein, we present two novel crystal structures of uridine monophosphate (UMP) and thymidine monophosphate (TMP) complexes with a macrocycle-based dinuclear receptor. Structural characterization of these complexes reveals that the receptor recognizes UMP through coordinate-covalent interactions with phosphates and π-π stackings with nucleobases and TMP through coordinate-covalent interactions with phosphate groups. Furthermore, the receptor has been shown to effectively bind nucleoside monophosphates in the order of GMP > AMP > UMP > TMP > CMP in water at physiological pH, as investigated by an indicator displacement assay.

Beta-Blockers, Trimethoprim-Sulfamethoxazole, and the Risk of Hyperkalemia Requiring Hospitalization in the Elderly: A Nested Case-Control Study

PubMed Central

Weir, Matthew A.; Juurlink, David N.; Gomes, Tara; Mamdani, Muhammad; Hackam, Daniel G.; Jain, Arsh K.

2010-01-01

Background and objectives: The simultaneous use of beta adrenergic receptor blockers (β-blockers) and trimethoprim-sulfamethoxazole (TMP-SMX) may confer a high risk of hyperkalemia. Design, setting, participants, & measurements: Two nested case-control studies were conducted to examine the association between hospitalization for hyperkalemia and the use of TMP-SMX in older patients receiving β-blockers. Linked health administrative records from Ontario, Canada, were used to assemble a cohort of 299,749 β-blockers users, aged 66 years or older and capture data regarding medication use and hospital admissions for hyperkalemia. Results: Over the study period from 1994 to 2008, 189 patients in this cohort were hospitalized for hyperkalemia within 14 days of receiving a study antibiotic. Compared with amoxicillin, the use of TMP-SMX was associated with a substantially greater risk of hyperkalemia requiring hospital admission (adjusted odds ratio, 5.1; 95% confidence interval [CI], 2.8 to 9.4). No such risk was identified with ciprofloxacin, norfloxacin, or nitrofurantoin. When dosing was considered, the association was greater at higher doses of TMP-SMX. When the primary analysis was repeated in a cohort of non-β-blocker users, the risk of hyperkalemia comparing TMP-SMX to amoxicillin was not significantly different from that found among β-blocker users. Conclusions: Although TMP-SMX is associated with an increased risk of hyperkalemia in older adults, these findings show no added risk when used in combination with β-blockers. PMID:20595693

Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency

PubMed Central

Garone, Caterina; Garcia-Diaz, Beatriz; Emmanuele, Valentina; Lopez, Luis C; Tadesse, Saba; Akman, Hasan O; Tanji, Kurenai; Quinzii, Catarina M; Hirano, Michio

2014-01-01

Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2−/−) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2−/− mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2−/−200dCMP/dTMP) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency. Subject Categories Genetics, Gene Therapy & Genetic Disease; Metabolism PMID:24968719

Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency.

PubMed

Garone, Caterina; Garcia-Diaz, Beatriz; Emmanuele, Valentina; Lopez, Luis C; Tadesse, Saba; Akman, Hasan O; Tanji, Kurenai; Quinzii, Catarina M; Hirano, Michio

2014-08-01

Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2(-/-)) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2(-/-) mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2(-/-200dCMP/) (dTMP)) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

Treating chancroid with enoxacin.

PubMed Central

Naamara, W; Kunimoto, D Y; D'Costa, L J; Ndinya-Achola, J O; Nsanze, H; Ronald, A R; Plummer, F A

1988-01-01

Increasing resistance of Haemophilus ducreyi to antimicrobials necessitates further trials of new antimicrobial agents for treating chancroid. Enoxacin has excellent in vitro activity against H ducreyi, and a randomised clinical trial of three doses of enoxacin 400 mg at intervals of 12 hours compared with a single dose of trimethoprim/sulphametrole (TMP/SMT) 640/3200 mg was therefore conducted. Of 169 men enrolled in the study, 86 received enoxacin and 83 received TMP/SMT. Ulcers were improved or cured in 65/73 men treated with enoxacin and 57/70 men treated with TMP/SMT. This difference was not significant. At 72 hours after treatment, H ducreyi was eradicated from ulcers of 72/77 men treated with enoxacin and of 67/74 of those treated with TMP/SMT. Patients with buboes responded equally well to both treatments. Of 100 H ducreyi strains tested, all were susceptible to both 0.25 mg/l enoxacin and the combination of 0.25 mg/l TMP and 5 mg/l SMT. Although most men treated with either regimen were cured, neither regimen appeared to be the optimum treatment for chancroid. This study shows the efficacy of enoxacin for a soft tissue infection caused by Gram negative organisms. PMID:3044978

Thermomagnetic identification of manganese and iron minerals present in soils and industrial dusts

NASA Astrophysics Data System (ADS)

Wawer, Małgorzata; Rachwał, Marzena; Jabłońska, Mariola; Krzykawski, Tomasz; Magiera, Tadeusz

2017-04-01

Many industries (e.g. metallurgy, power, cement, and coking plants) constitute a sources of industrial dusts containing technogenic magnetic particles (TMP). TMP are mostly iron oxides with ferrimagnetic or antiferromagnetic properties, therefore their presence in dusts, soils and sediments can be easily detected by magnetic susceptibility measurements. TMP, thanks their specific mineral and magnetic properties, and well developed specific surface area, are characterized by a chemical affinity for some elements like heavy metals. The main objective of this study was identification of manganese and iron (hydro)oxides occurring in industrial dusts and soils being under their deposition for long time period. In principle, Mn and Fe (hydro)oxides present in these samples originate from high-temperature technological processes. Soils samples (collected from different soil horizons) taken from surroundings of power station, iron/steel and non-ferrous plants as well as metallurgical dusts and fly ashes from power stations were subjected to investigation. During the studies temperature dependent magnetic susceptibility measurements and X-ray powder diffraction analyses were applied. Thermomagnetic analyses (K-T) revealed differences between samples from particular industries, however an inflexion at 450-500°C of all curves was observed indicating a probable occurrence of maghemite- or titanomagnetite-like phases. The curves of TMP emitted by power plants have inflection at 580 °C indicating that magnetite was the main magnetic phase. In case of TMP originated from non-ferrous metal smelting additional curve deflection at 130 and 210 °C occurred relating to intermediate titanomagnetite or iron sulfides. X-ray diffraction proved the occurrence of magnetite and maghemite in almost all samples, especially connected with power industry and iron/steel metallurgy. Mineral analysis revealed that kind of industrial process influenced on the dominating mineral forms found in polluted soils and specific industrial dusts. Fly ashes were composed mainly of anhydrite (2-46%), quartz (18-33%), muscovite (0-8%), feldspar (0-8%) and hematite (2-8%), while different spinels (19-53%), hematite (0-38%), wüstite (0-40%) and additives of calcite, halite, sylvine and graphite are the components of metallurgical dusts. Dusts from non-ferrous metal smelting contain Pb and Zn minerals: zincite (1-95%), lanarkite (0-45%), gordaite (0-10%), challacoloite and sphalerite. Additionally, some rare minerals were found in these dusts, such as: anglesite, sphalerite, galena, metasideronatrite and in soil, coronadite. Acknowledgements: The research project received funding from the National Science Centre of Poland on the basis of the decision number DEC-2013/09/B/ST10/02227.

Folding behaviour of Tachi-Miura polyhedron bellows.

PubMed

Yasuda, Hiromi; Yein, Thu; Tachi, Tomohiro; Miura, Koryo; Taya, Minoru

2013-11-08

In this paper, we examine the folding behaviour of Tachi-Miura polyhedron (TMP) bellows made of paper, which is known as a rigid-foldable structure, and construct a theoretical model to predict the mechanical energy associated with the compression of TMP bellows, which is compared with the experimentally measured energy, resulting in the gap between the mechanical work by the compression force and the bending energy distributed along all the crease lines. The extended Hamilton's principle is applied to explain the gap which is considered to be energy dissipation in the mechanical behaviour of TMP bellows.

Structural basis for regioisomerization in the alkali-metal-mediated zincation (AMMZn) of trifluoromethyl benzene by isolation of kinetic and thermodynamic intermediates.

PubMed

Armstrong, David R; Blair, Victoria L; Clegg, William; Dale, Sophie H; Garcia-Alvarez, Joaquin; Honeyman, Gordon W; Hevia, Eva; Mulvey, Robert E; Russo, Luca

2010-07-14

Performed with a desire to advance knowledge of the structures and mechanisms governing alkali-metal-mediated zincation, this study monitors the reaction between the TMP-dialkylzincate reagent [(TMEDA)Na(TMP)((t)Bu)Zn((t)Bu)] 1 and trifluoromethyl benzene C(6)H(5)CF(3) 2. A complicated mixture of products is observed at room temperature. X-ray crystallography has identified two of these products as ortho- and meta-regioisomers of heterotrianionic [(TMEDA)Na(TMP)(C(6)H(4)-CF(3))Zn((t)Bu)], 3-ortho and 3-meta, respectively. Multinuclear NMR data of the bulk crystalline product confirm the presence of these two regioisomers as well as a third isomer, 3-para, in a respective ratio of 20:11:1, and an additional product 4, which also exhibits ortho-zincation of the aryl substrate. Repeating the reaction at 0 degrees C gave exclusively 4, which was crystallographically characterized as [{(TMEDA)(2)Na}(+){Zn(C(6)H(4)-CF(3))((t)Bu)(2)}(-)]. Mimicking the original room-temperature reaction, this kinetic product was subsequently reacted with TMP(H) to afford a complicated mixture of products, including significantly the three regioisomers of 3. Surprisingly, 4 adopts a solvent-separated ion pair arrangement in contrast to the contacted ion variants of 3-ortho and 3-meta. Aided by DFT calculations on model systems, discussion focuses on the different basicities, amido or alkyl, and steps, exhibited in these reactions, and how the structures and bonding within these isolated key metallic intermediates (prior to any electrophilic interception step), specifically the interactions involving the alkali metal, influence the regioselectivity of the Zn-H exchange process.

Strength and Formability Improvement of Al-Cu-Mn Aluminum Alloy Complex Parts by Thermomechanical Treatment with Sheet Hydroforming

NASA Astrophysics Data System (ADS)

Chen, Yi-Zhe; Liu, Wei; Yuan, Shi-Jian

2015-05-01

Normally, the strength and formability of aluminum alloys can be increased largely by severe plastic deformation and heat treatment. However, many plastic deformation processes are more suitable for making raw material, not for formed parts. In this article, an experimental study of the thermomechanical treatment by using the sheet hydroforming process was developed to improve both mechanical strength and formability for aluminum alloys in forming complex parts. The limiting drawing ratio, thickness, and strain distribution of complex parts formed by sheet hydroforming were investigated to study the formability and sheet-deformation behavior. Based on the optimal formed parts, the tensile strength, microhardness, grain structure, and strengthening precipitates were analyzed to identify the strengthening effect of thermomechanical treatment. The results show that in the solution state, the limiting drawing ratio of cylindrical parts could be increased for 10.9% compared with traditional deep drawing process. The peak values of tensile stress and microhardness of formed parts are 18.0% and 12.5% higher than that in T6 state. This investigation shows that the thermomechanical treatment by sheet hydroforming is a potential method for the products manufacturing of aluminum alloy with high strength and good formability.

Fluoride and calcium concentrations in the biofilm fluid after use of fluoridated dentifrices supplemented with polyphosphate salts.

PubMed

Nagata, Mariana Emi; Delbem, Alberto Carlos Botazzo; Hall, Kevin Bruce; Buzalaf, Marília Afonso Rabelo; Pessan, Juliano Pelim

2017-04-01

The present study evaluated fluoride (F) and calcium (Ca) concentrations in the biofilm fluid formed in situ under cariogenic challenge after using F dentifrices supplemented or not with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP). Volunteers (n = 12) were randomly divided into 5 groups according to the toothpastes used: placebo (without F, CaGP or TMP), 1100 ppm F (1100F) and low-fluoride dentifrice (LFD, 550 ppm F) with no supplementation (550F) or supplemented with 1 % TMP (550F-TMP) or 0.25 % CaGP (550F-CaGP). In each phase, volunteers wore palatal appliances containing 4 bovine enamel blocks. Cariogenic challenge was performed with 30 % sucrose solution, 6 times/day. On the morning of the eigth day, biofilm samples were collected 12 h and 1 h after brushing and cariogenic challenge. F and Ca analyses in the biofilm fluid were performed with the inverted electrode after buffering with TISAB III and using the Arsenazo III method, respectively. Data were submitted to two-way ANOVA (repeated measures) and Student-Newman-Keuls test (p < 0.05). A dose-response relationship was verified between F concentrations in the dentifrices and in the biofilm fluid. Significant differences were observed among placebo, 550F, and 1100F only 1 h after brushing, without statistical differences among 550F, 550F-TMP, and 550F-CaGP. No defined trend was observed among the groups regarding Ca concentrations, with the highest values seen for placebo and 550F-CaGP. The anticaries effect of LFDs supplemented with CaGP or TMP cannot be related to an increased availability of F and Ca in the biofilm fluid. The better performance of LFDs containing CaGP or TMP shown in previous studies should be attributed to their ability to interact with tooth enamel and with the biofilm, rather to their effect on the biofilm fluid.

Factors affecting hydrogen-tunneling contribution in hydroxylation reactions promoted by oxoiron(IV) porphyrin π-cation radical complexes.

PubMed

Cong, Zhiqi; Kinemuchi, Haruki; Kurahashi, Takuya; Fujii, Hiroshi

2014-10-06

Hydrogen atom transfer with a tunneling effect (H-tunneling) has been proposed to be involved in aliphatic hydroxylation reactions catalyzed by cytochrome P450 and synthetic heme complexes as a result of the observation of large hydrogen/deuterium kinetic isotope effects (KIEs). In the present work, we investigate the factors controlling the H-tunneling contribution to the H-transfer process in hydroxylation reaction by examining the kinetics of hydroxylation reactions at the benzylic positions of xanthene and 1,2,3,4-tetrahydronaphthalene by oxoiron(IV) 5,10,15,20-tetramesitylporphyrin π-cation radical complexes ((TMP(+•))Fe(IV)O(L)) under single-turnover conditions. The Arrhenius plots for these hydroxylation reactions of H-isotopomers have upwardly concave profiles. The Arrhenius plots of D-isotopomers, clear isosbestic points, and product analysis rule out the participation of thermally dependent other reaction processes in the concave profiles. These results provide evidence for the involvement of H-tunneling in the rate-limiting H-transfer process. These profiles are simulated using an equation derived from Bell's tunneling model. The temperature dependence of the KIE values (k(H)/k(D)) determined for these reactions indicates that the KIE value increases as the reaction temperature becomes lower, the bond dissociation energy (BDE) of the C-H bond of a substrate becomes higher, and the reactivity of (TMP(+•))Fe(IV)O(L) decreases. In addition, we found correlation of the slope of the ln(k(H)/k(D)) - 1/T plot and the bond strengths of the Fe═O bond of (TMP(+•))Fe(IV)O(L) estimated from resonance Raman spectroscopy. These observations indicate that these factors modulate the extent of the H-tunneling contribution by modulating the ratio of the height and thickness of the reaction barrier.

A prospective controlled investigation of prophylactic trimethoprim/sulfamethoxazole in hospitalized granulocytopenic patients.

PubMed

Gurwith, M J; Brunton, J L; Lank, B A; Harding, G K; Ronald, A R

1979-02-01

Oral trimethoprim/sulfamethoxazole (TMP/SMZ) therapy was investigated in the prophylaxis of infections in granulocytopenia. Hospitalized granulocytopenic patients were allocated at random to receive TMP/SMZ (group 1) or to a control group (group 2). The percentage of febrile granulocytopenic days was significantly reduced in group 1, 19 per cent compared to 39 per cent in group 2 (P less than 0.01). In group 1, there were no bacteremias in 59 episodes of granulocytopenia (909 days). In group 2, there were nine bacteremias in 52 episodes of granulocytopenia (796 days)(P = 0.001). Disseminated candidiasis developed in two patients in each group. Candida occurred in similar numbers in surveillance cultures in both groups; Staphylococcus aureus and Pseudomonas aeruginosa were slightly decreased, and Enterobacteriaceae resistant to TMP slightly increased in group 1. This study suggest that oral prophylactic TMP/SMZ therapy is an effective, well tolerated, easily administered alternative to "gut sterilization" with nonabsorbable antibiotics.

Supramolecular Assembly of Uridine Monophosphate (UMP) and Thymidine Monophosphate (TMP) with a Dinuclear Copper(II) Receptor

PubMed Central

2017-01-01

Understanding the intermolecular interactions between nucleotides and artificial receptors is crucial to understanding the role of nucleic acids in living systems. However, direct structural evidence showing precise interactions and bonding features of a nucleoside monophosphate (NMP) with a macrocycle-based synthetic molecule has not been provided so far. Herein, we present two novel crystal structures of uridine monophosphate (UMP) and thymidine monophosphate (TMP) complexes with a macrocycle-based dinuclear receptor. Structural characterization of these complexes reveals that the receptor recognizes UMP through coordinate–covalent interactions with phosphates and π–π stackings with nucleobases and TMP through coordinate–covalent interactions with phosphate groups. Furthermore, the receptor has been shown to effectively bind nucleoside monophosphates in the order of GMP > AMP > UMP > TMP > CMP in water at physiological pH, as investigated by an indicator displacement assay. PMID:29214233

Reduction in clinical response to empiric antimicrobial therapy of febrile granulocytopenic patients receiving TMP/SMX infection prophylaxis

PubMed Central

Bow, Eric J; Pater, Joseph L; Louie, Thomas J; Feld, Ronald; Mandell, Lionel; Robson, Hugh G; Chow, Anthony; Belch, Andrew; Miedzinski, Lilly; Paul, Nancy; Elliott, Catherine R; Willan, Andrew R

1992-01-01

In the course of a multicentre clinical trial evaluating two antibacterial regimens for the empiric treatment of suspected infection in febrile neutropenic cancer patients, a suboptimal response was noted among recipients of antibacterial prophylaxis with trimethoprim/sulphamethoxazole (TMP/SMX). Multivariate analysis identified TMP/SMX prophylaxis as a predictor of poor outcome independent of other variables such as classification of infection, marrow recovery, neutrophil count at first fever, indwelling central venous catheter use, and underlying disease. This effect appeared to be restricted to recipients of tobramycin plus ticarcillin (TT). TMP/SMX suppresses potentially pathogenic aerobic Gram-negative bacilli and allows colonization and subsequent infection by Gram-positive microorganisms against which TT-like regimens have limited activity. Recognition of this phenomenon may permit a more appropriate selection of antibacterial agents for the therapy of suspected infection in the neutropenic patient. PMID:22416197

Influence of crystal habit on trimethoprim suspension formulation.

PubMed

Tiwary, A K; Panpalia, G M

1999-02-01

The role of crystal habit in influencing the physical stability and pharmacokinetics of trimethoprim suspensions was examined. Different habits for trimethoprim (TMP) were obtained by recrystallizing the commercial sample (PD) utilizing solvent-change precipitation method. Four distinct habits (microscopic observation) belonging to the same polymorphic state (DSC studies) were selected for studies. Preformulation and formulation studies were carried out on suspension dosage forms containing these crystals. The freshly prepared suspensions were also evaluated for their pharmacokinetic behaviour on healthy human volunteers using a cross over study. Variation of crystallization conditions produces different habits of TMP. Among the different crystal habits exhibiting same polymorphic state, the most anisometric crystal showed best physical stability in terms of sedimentation volume and redispersibility. However, habit did not significantly affect the extent of TMP excreted in urine. Modification of surface morphology without significantly altering the polymorphic state can be utilized for improving physical stability of TMP suspensions. However, the pharmacokinetic profile remains unaltered.

DESIGN, SYNTHESIS, AND APPLICATION OF THE TRIMETHOPRIM-BASED CHEMICAL TAG FOR LIVE CELL IMAGING

PubMed Central

Jing, Chaoran; Cornish, Virginia W.

2013-01-01

Over the past decade chemical tags have been developed to complement the use of fluorescent proteins in live cell imaging. Chemical tags retain the specificity of protein labeling achieved with fluorescent proteins through genetic encoding, but provide smaller, more robust tags and modular use of organic fluorophores with high photon-output and tailored functionalities. The trimethoprim-based chemical tag (TMP-tag) was initially developed based on the high affinity interaction between E.coli dihydrofolatereductase and the antibiotic trimethoprim and subsequently rendered covalent and fluorogenic via proximity-induced protein labeling reactions. To date, the TMP-tag is one of the few chemical tags that enable intracellular protein labeling and high-resolution live cell imaging. Here we describe the general design, chemical synthesis, and application of TMP-tag for live cell imaging. Alternative protocols for synthesizing and using the covalent and the fluorogenic TMP-tags are also included. PMID:23839994

Tetramethylpyrazine Protects Against Oxygen-Glucose Deprivation-Induced Brain Microvascular Endothelial Cells Injury via Rho/Rho-kinase Signaling Pathway.

PubMed

Yang, Guang; Qian, Chen; Wang, Ning; Lin, Chenyu; Wang, Yan; Wang, Guangyun; Piao, Xinxin

2017-05-01

Tetramethylpyrazine (TMP, also known as Ligustrazine), which is isolated from Chinese Herb Medicine Ligustium wollichii Franchat (Chuan Xiong), has been widely used in China for the treatment of ischemic stroke by Chinese herbalists. Brain microvascular endothelial cells (BMECs) are the integral parts of the blood-brain barrier (BBB), protecting BMECs against oxygen-glucose deprivation (OGD) which is important for the treatment of ischemic stroke. Here, we investigated the protective mechanisms of TMP, focusing on OGD-injured BMECs and the Rho/Rho-kinase (Rho-associated kinases, ROCK) signaling pathway. The model of OGD-injured BMECs was established in this study. BMECs were identified by von Willebrand factor III staining and exposed to fasudil, or TMP at different concentrations (14.3, 28.6, 57.3 µM) for 2 h before 24 h of OGD injury. The effect of each treatment was examined by cell viability assays, measurement of intracellular reactive oxygen species (ROS), and transendothelial electric resistance and western blot analysis (caspase-3, endothelial nitric oxide synthase (eNOS), RhoA, Rac1). Our results show that TMP significantly attenuated apoptosis and the permeability of BMECs induced by OGD. In addition, TMP could notably down-regulate the characteristic proteins in Rho/ROCK signaling pathway such as RhoA and Rac1, which triggered abnormal changes of eNOS and ROS, respectively. Altogether, our results show that TMP has a strong protective effect against OGD-induced BMECs injury and suggest that the mechanism might be related to the inhibition of the Rho/ROCK signaling pathway.

Sodium trimetaphosphate enhances the effect of 250 p.p.m. fluoride toothpaste against enamel demineralization in vitro.

PubMed

Missel, Emilene M C; Cunha, Robson F; Vieira, Ana E M; Cruz, Nathália V S; Castilho, Flavia C N; Delbem, Alberto C B

2016-08-01

This in vitro study investigated the effect of sodium trimetaphosphate (TMP), added to toothpaste containing 250 p.p.m. fluoride, on enamel demineralization. Bovine enamel blocks (n = 96) were subjected to five pH cycles over a 7-d period and treatment with suspensions of toothpastes containing 0, 250, 500, and 1,100 p.p.m. fluoride (as sodium fluoride), as well as with 250 p.p.m. fluoride containing TMP at 0.25, 0.5, 1.0, and 3.0%. Treatment with toothpaste suspensions was performed under agitation twice a day, for 1 min. Surface and cross-sectional hardness, and fluoride firmly bound to enamel, were quantified. Data were subjected to one-way anova, followed by Tukey's test. Low-fluoride toothpastes containing TMP at 0.25-1.0% resulted in enamel mineral loss similar to that seen for the toothpaste containing 1,100 p.p.m. fluoride. Also, the addition of TMP to the toothpaste containing 250 p.p.m. fluoride promoted enamel fluoride concentrations similar to those obtained for the 500 p.p.m. fluoride group. The toothpaste containing 250 p.p.m. fluoride and 0.25% TMP led to the lowest mineral loss among all groups. It was concluded that the addition of as little as 0.25% TMP to a toothpaste containing 250 p.p.m. fluoride can reduce enamel demineralization to levels similar to those seen for a conventional toothpaste containing 1,100 p.p.m. fluoride, in vitro. © 2016 Eur J Oral Sci.

Polarizable Multipole-Based Force Field for Dimethyl and Trimethyl Phosphate

PubMed Central

2015-01-01

Phosphate groups are commonly observed in biomolecules such as nucleic acids and lipids. Due to their highly charged and polarizable nature, modeling these compounds with classical force fields is challenging. Using quantum mechanical studies and liquid-phase simulations, the AMOEBA force field for dimethyl phosphate (DMP) ion and trimethyl phosphate (TMP) has been developed. On the basis of ab initio calculations, it was found that ion binding and the solution environment significantly impact both the molecular geometry and the energy differences between conformations. Atomic multipole moments are derived from MP2/cc-pVQZ calculations of methyl phosphates at several conformations with their chemical environments taken into account. Many-body polarization is handled via a Thole-style induction model using distributed atomic polarizabilities. van der Waals parameters of phosphate and oxygen atoms are determined by fitting to the quantum mechanical interaction energy curves for water with DMP or TMP. Additional stretch-torsion and angle-torsion coupling terms were introduced in order to capture asymmetry in P–O bond lengths and angles due to the generalized anomeric effect. The resulting force field for DMP and TMP is able to accurately describe both the molecular structure and conformational energy surface, including bond and angle variations with conformation, as well as interaction of both species with water and metal ions. The force field was further validated for TMP in the condensed phase by computing hydration free energy, liquid density, and heat of vaporization. The polarization behavior between liquid TMP and TMP in water is drastically different. PMID:26574325

Enhancing the ABAQUS thermomechanics code to simulate multipellet steady and transient LWR fuel rod behavior

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

R. L. Williamson

A powerful multidimensional fuels performance analysis capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. Enhanced capabilities are described, including: UO2 temperature and burnup dependent thermal properties, solid and gaseous fission product swelling, fuel densification, fission gas release, cladding thermal and irradiation creep, cladding irradiation growth, gap heat transfer, and gap/plenum gas behavior during irradiation. This new capability is demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multipellet fuel rod, during both steady and transient operation. Comparisons are made between discrete andmore » smeared-pellet simulations. Computational results demonstrate the importance of a multidimensional, multipellet, fully-coupled thermomechanical approach. Interestingly, many of the inherent deficiencies in existing fuel performance codes (e.g., 1D thermomechanics, loose thermomechanical coupling, separate steady and transient analysis, cumbersome pre- and post-processing) are, in fact, ABAQUS strengths.« less

An Escherichia coli Strain, PGB01, Isolated from Feral Pigeon Faeces, Thermally Fit to Survive in Pigeon, Shows High Level Resistance to Trimethoprim

PubMed Central

Kachhap, Sangita; Nanda, Ashis Kumar; Chakraborty, Ranadhir

2015-01-01

In this study, of the hundred Escherichia coli strains isolated from feral Pigeon faeces, eighty five strains were resistant to one or more antibiotics and fifteen sensitive to all the antibiotics tested. The only strain (among all antibiotic-resistant E. coli isolates) that possessed class 1 integron was PGB01. The dihydrofolate reductase gene of the said integron was cloned, sequenced and expressed in E. coli JM109. Since PGB01 was native to pigeon’s gut, we have compared the growth of PGB01 at two different temperatures, 42°C (normal body temperature of pigeon) and 37°C (optimal growth temperature of E. coli; also the human body temperature), with E. coli K12. It was found that PGB01 grew better than the laboratory strain E. coli K12 at 37°C as well as at 42°C. In the thermal fitness assay, it was observed that the cells of PGB01 were better adapted to 42°C, resembling the average body temperature of pigeon. The strain PGB01 also sustained more microwave mediated thermal stress than E. coli K12 cells. The NMR spectra of the whole cells of PGB01 varied from E. coli K12 in several spectral peaks relating some metabolic adaptation to thermotolerance. On elevating the growth temperature from 37°C to 42°C, susceptibility to kanamycin (both strains were sensitive to it) of E. coli K12 was increased, but in case of PGB01 no change in susceptibility took place. We have also attempted to reveal the basis of trimethoprim resistance phenotype conferred by the dfrA7 gene homologue of PGB01. Molecular Dynamics (MD) simulation study of docked complexes, PGB01-DfrA7 and E. coli TMP-sensitive-Dfr with trimethoprim (TMP) showed loss of some of the hydrogen and hydrophobic interaction between TMP and mutated residues in PGB01-DfrA7-TMP complex compared to TMP-sensitive-Dfr-TMP complex. This loss of interaction entails decrease in affinity of TMP for PGB01-DfrA7 compared to TMP-sensitive-Dfr. PMID:25750990

Integration of aerobic granular sludge and mesh filter membrane bioreactor for cost-effective wastewater treatment.

PubMed

Li, Wen-Wei; Wang, Yun-Kun; Sheng, Guo-Ping; Gui, Yong-Xin; Yu, Lei; Xie, Tong-Qing; Yu, Han-Qing

2012-10-01

Conventional MBR has been mostly based on floc sludge and the use of costly microfiltration membranes. Here, a novel aerobic granule (AG)-mesh filter MBR (MMBR) process was developed for cost-effective wastewater treatment. During 32-day continuous operation, a predominance of granules was maintained in the system, and good filtration performance was achieved at a low trans-membrane pressure (TMP) of below 0.025 m. The granules showed a lower fouling propensity than sludge flocs, attributed to the formation of more porous biocake layer at mesh surface. A low-flux and low-TMP filtration favored a stable system operation. In addition, the reactor had high pollutant removal efficiencies, with a 91.4% chemical oxygen demand removal, 95.7% NH(4)(+) removal, and a low effluent turbidity of 4.1 NTU at the stable stage. This AG-MMBR process offers a promising technology for low-cost and efficient treatment of wastewaters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oily wastewater treatment by ultrafiltration using Taguchi experimental design.

PubMed

Salahi, A; Mohammadi, T

2011-01-01

In this research, results of an experimental investigation on separation of oil from a real oily wastewater using an ultrafiltration (UF) polymeric membrane are presented. In order to enhance the performance of UF in API separator effluent treatment and to get more permeation flux (PF), effects of operating factors on the yield of PF were studied. Five factors at four levels were investigated: trans-membrane pressure (TMP), temperature (T), cross flow velocity (CFV), pH and salt concentration (SC). Taguchi method (L(16) orthogonal array (OA)) was used. Analysis of variance (ANOVA) was applied to calculate sum of square, variance, error variance and contribution percentage of each factor on response. The optimal levels thus determined for the four influential factors were: TMP, 3 bar; T, 40˚C; CFV, 1.0 m/s; SC, 25 g/L and pH, 8. The results showed that CFV and SC are the most and the least effective factors on PF, respectively. Increasing CFV, TMP, T and pH caused the better performance of UF membrane process due to enhancement of driving force and fouling residence. Also, effects of oil concentration (OC) in the wastewater on PF and total organic carbon (TOC) rejection were investigated. Finally, the highest TOC rejection was found to be 85%.

Folding behaviour of Tachi–Miura polyhedron bellows

PubMed Central

Yasuda, Hiromi; Yein, Thu; Tachi, Tomohiro; Miura, Koryo; Taya, Minoru

2013-01-01

In this paper, we examine the folding behaviour of Tachi–Miura polyhedron (TMP) bellows made of paper, which is known as a rigid-foldable structure, and construct a theoretical model to predict the mechanical energy associated with the compression of TMP bellows, which is compared with the experimentally measured energy, resulting in the gap between the mechanical work by the compression force and the bending energy distributed along all the crease lines. The extended Hamilton's principle is applied to explain the gap which is considered to be energy dissipation in the mechanical behaviour of TMP bellows. PMID:24204186

Effectiveness of a Toothpaste with Low Fluoride Content Combined with Trimetaphosphate on Dental Biofilm and Enamel Demineralization in situ.

PubMed

Takeshita, Eliana M; Danelon, Marcelle; Castro, Luciene P; Sassaki, Kikue T; Delbem, Alberto C B

2015-01-01

The aim of the present study was to evaluate in situ whether a toothpaste with low fluoride associated with sodium trimetaphosphate (TMP) would provide similar effect to that of a 1,100 ppm F toothpaste. This crossover double-blind study consisted of 4 phases (14 days each), during which 10 volunteers wore oral appliances containing 4 enamel bovine blocks. The cariogenic challenge was performed by the application of a 20% sucrose solution (6×/day). The toothpaste treatments (2×/day) were: placebo, 500 ppm F, 500 ppm F plus 1% TMP, and 1,100 ppm F. At the end, enamel mineral loss and biofilm composition were analyzed. The toothpaste with 500 ppm F plus 1% TMP showed the lowest mineral loss (p < 0.05). Regarding the fluoride and calcium concentrations in the enamel and in the biofilm, there were no significant differences between 500 ppm F plus 1% TMP, and 1,100 ppm F toothpastes (p > 0.569), but they were significantly different when compared to toothpaste with 500 ppm F (p < 0.050). The addition of 1% TMP to a low-fluoride toothpaste reduces enamel demineralization in situ similar to a 1,100 ppm F toothpaste. © 2015 S. Karger AG, Basel.

Deoxycytidine and deoxythymidine treatment for thymidine kinase 2 deficiency

PubMed Central

Lopez-Gomez, Carlos; Levy, Rebecca J; Sanchez-Quintero, Maria J; Juanola-Falgarona, Marti; Barca, Emanuele; Garcia-Diaz, Beatriz; Tadesse, Saba; Garone, Caterina; Hirano, Michio

2017-01-01

Objective Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene TK2 cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, dCMP and dTMP, prolongs the lifespan of Tk2-deficient (Tk2-/-) mice by 2-3 fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: 1) deoxynucleosides might be the major active agents and 2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. Methods To test these hypotheses, we assessed two therapies in Tk2-/- mice: 1) dT+dC and 2) co-administration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. Results We observed that dC+dT delayed disease onset, prolonged lifespan of Tk2-deficient mice, and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased lifespan of Tk2-/- animals compared to dCMP+dTMP. Interpretation Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. PMID:28318037

The crystal structure of ribonuclease A in complex with thymidine-3'-monophosphate provides further insight into ligand binding.

PubMed

Doucet, Nicolas; Jayasundera, Thusitha B; Simonović, Miljan; Loria, J Patrick

2010-08-15

Thymidine-3'-monophosphate (3'-TMP) is a competitive inhibitor analogue of the 3'-CMP and 3'-UMP natural product inhibitors of bovine pancreatic ribonuclease A (RNase A). Isothermal titration calorimetry experiments show that 3'-TMP binds the enzyme with a dissociation constant (K(d)) of 15 microM making it one of the strongest binding members of the five natural bases found in nucleic acids (A, C, G, T, and U). To further investigate the molecular properties of this potent natural affinity, we have determined the crystal structure of bovine pancreatic RNase A in complex with 3'-TMP at 1.55 A resolution and we have performed NMR binding experiments with 3'-CMP and 3'-TMP. Our results show that binding of 3'-TMP is very similar to other natural and non-natural pyrimidine ligands, demonstrating that single nucleotide affinity is independent of the presence or absence of a 2'-hydroxyl on the ribose moiety of pyrimidines and suggesting that the pyrimidine binding subsite of RNase A is not a significant contributor of inhibitor discrimination. Accumulating evidence suggests that very subtle structural, chemical, and potentially motional variations contribute to ligand discrimination in this enzyme. 2010 Wiley-Liss, Inc.

A multidimensional high performance liquid chromatography method coupled with amperometric detection using a boron-doped diamond electrode for the simultaneous determination of sulfamethoxazole and trimethoprim in bovine milk.

PubMed

Andrade, Leonardo S; de Moraes, Marcela C; Rocha-Filho, Romeu C; Fatibello-Filho, Orlando; Cass, Quezia B

2009-11-10

The development and validation of a multidimensional HPLC method using an on-line clean-up column coupled with amperometric detection employing a boron-doped diamond (BDD) electrode for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in bovine milk are presented. Aliquots of pre-prepared skim-milk samples were directly injected into a RAM octyl-BSA column in order to remove proteins that otherwise would interfere with milk analysis. After exclusion of the milk proteins, SMX and TMP were transferred to the analytical column (an octyl column) and the separation of the compounds from one another and from other endogenous milk components was achieved. SMX and TMP were detected amperometrically at 1.25V vs. Ag/AgCl (3.0molL(-1) KCl). Results with good linearity in the concentration ranges 50-800 and 25-400microgL(-1) for SMX and TMP, respectively, were obtained and no fouling of the BDD electrode was observed within the experimental period of several hours. The intra- and inter-assay coefficients of variation were less than 10% for both drugs and the obtained LOD values for SMX and TMP were 25.0 and 15.0microgL(-1), respectively.

The Risk of Overanticoagulation with Antibiotic Use in Outpatients on Stable Warfarin Regimens

PubMed Central

Glasheen, Jeffrey J; Fugit, Randolph V; Prochazka, Allan V

2005-01-01

BACKGROUND Medication interactions account for a significant proportion of overanticoagulation in warfarin users. However, little is known about the incidence or degree of interaction with commonly used oral antibiotics. OBJECTIVE To investigate the incidence and degree of overanticoagulation associated with commonly used oral antibiotics. DESIGN Retrospective cohort study of patients using warfarin who initiated an antibiotic (azithromycin, levofloxacin, or trimethoprim/sulfamethoxazole (TMP/SMX)) or terazosin for clinical indications between January 1998 and December 2002. The incidence of international normalized ratio (INR) elevation and the degree of change and bleeding events after institution of either medication type was recorded. SUBJECTS Patients at a university-affiliated Veteran's Affairs Medical Center. RESULTS The mean change in INR was −0.15 for terazosin, 0.51 for azithromycin, 0.85 for levofloxacin, and 1.76 for TMP/SMX. These mean INR changes in the antibiotic groups were all statistically different from the terazosin group. The incidence of supratherapeutic INR was 5% for terazosin, 31% for azithromycin, 33% for levofloxacin, and 69% for TMP/SMX. The incidence of absolute INR >4.0 was 0% for terazosin, 16% for azithromycin, 19% for levofloxacin, and 44% for TMP/SMX. CONCLUSIONS Among acutely ill outpatients, oral antibiotics (azithromycin, levofloxacin, and TMP/SMX) increase the incidence and degree of overanticoagulation. PMID:16050864

A Trimethoprim Conjugate of Thiomaltose Has Enhanced Antibacterial Efficacy In Vivo.

PubMed

Wang, Xiaojian; Borges, Clarissa A; Ning, Xinghai; Rafi, Mohammad; Zhang, Jingtuo; Park, Bora; Takemiya, Kiyoko; Lo Sterzo, Carlo; Taylor, W Robert; Riley, Lee; Murthy, Niren

2018-05-16

Trimethoprim is one of the most widely used antibiotics in the world. However, its efficacy is frequently limited by its poor water solubility and dose limiting toxicity. Prodrug strategies based on conjugation of oligosaccharides to trimethoprim have great potential for increasing the solubility of trimethoprim and lowering its toxicity, but they have been challenging to develop due to the sensitivity of trimethoprim to chemical modifications, and the rapid degradation of oligosaccharides in serum. In this report, we present a trimethoprim conjugate of maltodextrin termed TM-TMP, which increased the water solubility of trimethoprim by over 100 times, was stable to serum enzymes, and was active against urinary tract infections in mice. TM-TMP is composed of thiomaltose conjugated to trimethoprim, via a self-immolative disulfide linkage, and releases 4'-OH-trimethoprim (TMP-OH) after disulfide cleavage, which is a known metabolic product of trimethoprim and is as potent as trimethoprim. TM-TMP also contains a new maltodextrin targeting ligand composed of thiomaltose, which is stable to hydrolysis by serum amylases and therefore has the metabolic stability needed for in vivo use. TM-TMP has the potential to significantly improve the treatment of a wide number of infections given its high water solubility and the widespread use of trimethoprim.

Advance development of a technique for characterizing the thermomechanical properties of thermally stable polymers

NASA Technical Reports Server (NTRS)

Gillham, J. K.; Stadnicki, S. J.; Hazony, Y.

1974-01-01

The torsional braid experiment has been interfaced with a centralized hierarchical computing system for data acquisition and data processing. Such a system, when matched by the appropriate upgrading of the monitoring techniques, provides high resolution thermomechanical spectra of rigidity and damping, and their derivatives with respect to temperature.

Rolling Contact Fatigue Testing of Thermomechanically Processed M-50 Steel.

DTIC Science & Technology

1984-12-01

as I floundered through the early stages of th- s research with question after question. And I would be remiss not to cite Mr. Tom Kellogg , who--as all...INSTRUCTIONS _ _ _ __-_BEFORE COMPLETING FORM 1. REPORT NUMBER A o GOVA ACCESSION NO, 2jECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) S TYPE OF...REPORT & PERIOD COVERED Rolling Contact Fatigue Testing of Master’s Thesis Thermomechanically Processed M-50 Steel December_1984 S . PERFORMING ORG

Processing of fine grained AISI 304L austenitic stainless steel by cold rolling and high-temperature short-term annealing

NASA Astrophysics Data System (ADS)

Naghizadeh, Meysam; Mirzadeh, Hamed

2018-05-01

An advanced thermomechanical process based on the formation and reversion of deformation-induced martensite was used to refine the grain size and enhance the hardness of an AISI 304L austenitic stainless steel. Both low and high reversion annealing temperatures and also the repetition of the whole thermomechanical cycle were considered. While a microstructure with average austenite grain size of a few micrometers was achieved based on cold rolling and high-temperature short-term annealing, an extreme grain refinement up to submicrometer regime was obtained by cold rolling followed by low-temperature long-term annealing. However, the required annealing time was found to be much longer, which negates its appropriateness for industrial production. While a magnificent grain refinement was achieved by one pass of the high-temperature thermomechanical process, the reduction in grain size was negligible by the repetition of the whole cycle. It was found that the hardness of the thermomechanically processed material is much higher than that of the as-received material. The results of the present work were shown to be compatible with the general trend of grain size dependence of hardness for AISI 304L stainless steel based on the Hall-Petch relationship. The results were also discussed based on the X-ray evaluation of dislocation density by modified Williamson-Hall plots.

A process efficiency assessment of serum protein removal from milk using ceramic graded permeability microfiltration membrane.

PubMed

Tremblay-Marchand, D; Doyen, A; Britten, M; Pouliot, Y

2016-07-01

Microfiltration (MF) is a well-known process that can be used in the dairy industry to separate caseins from serum proteins (SP) in skim milk using membranes with a pore diameter of 0.1μm. Graded permeability ceramic membranes have been studied widely as means of improving milk fractionation by overcoming problems encountered with other MF membranes. The ideal operating parameters for process efficiency in terms of membrane selectivity, permeate flux, casein loss, SP transmission, energy consumption, and dilution with water remain to be determined for this membrane. Our objective was to evaluate the effects of transmembrane pressure (TMP), volumetric concentration factor (VCF), and diafiltration on overall process efficiency. Skim milk was processed using a pilot-scale MF system equipped with 0.72-m(2) graded permeability membranes with a pore size of 0.1μm. In the first experiment, in full recycle mode, TMP was set at 124, 152, 179, or 207 kPa by adjusting the permeate pressure at the outlet. Whereas TMP had no significant effect on permeate and retentate composition, 152 kPa was found to be optimal for SP removal during concentration and concentration or diafiltration experiments. When VCF was increased to 3×, SP rejection coefficient increased along with energy consumption and total casein loss, whereas SP removal rate decreased. Diafiltering twice allowed an increase in total SP removal but resulted in a substantial increase in energy consumption and casein loss. It also reduced the SP removal rate by diluting permeate. The membrane surface area required for producing cheese milk by blending whole milk, cream, and MF retentate (at different VCF) was estimated for different cheese milk casein concentrations. For a given casein concentration, the same quantity of permeate and SP would be produced, but less membrane surface area would be needed at a lower retentate VCF. Microfiltration has great potential as a process of adding value to conventional cheesemaking processes, but its cost-effectiveness at a large scale remains to be demonstrated. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Symptomatic hypoglycemia associated with trimethoprim/sulfamethoxazole and repaglinide in a diabetic patient.

PubMed

Roustit, Matthieu; Blondel, Emeline; Villier, Céline; Fonrose, Xavier; Mallaret, Michel P

2010-04-01

To report a case of clinically significant hypoglycemia attributed to the concomitant use of trimethoprim/sulfamethoxazole (TMP/SMX) and repaglinide by a diabetic patient. A 76-year-old diabetic patient with impaired renal function and no history of hypoglycemia was receiving treatment with repaglinide 1 mg 3 times daily. Five days after TMP/SMX therapy was started for a urinary tract infection, the man developed symptomatic hypoglycemia. Repaglinide and TMP/SMX were stopped and intravenous D-glucose was administered to normalize glucose levels. Repaglinide, but not TMP/SMX, was reintroduced 5 days later and no other hypoglycemic episode occurred. Objective causality assessments revealed that the interaction was probable (World Health Organization-Uppsala Monitoring Centre) or possible (Horn Drug Interaction Probability Scale). This interaction between TMP/SMX and repaglinide was predictable according to available pharmacokinetic data in healthy subjects. Trimethoprim induced CYP2C8 inhibition, thus increasing the plasma concentration of repaglinide. This interaction is mentioned in the repaglinide product information. To our knowledge, however, no case of symptomatic hypoglycemia associated with a combination of repaglinide and trimethoprim has been described before. This discrepancy may be explained by the subtherapeutic dosage used in the pharmacokinetic study. Moreover, our patient had impaired renal function, which may have led to trimethoprim accumulation and potentiated its interaction with repaglinide. A direct lowering of blood glucose levels due to sulfamethoxazole, also potentiated by renal failure, could also be involved in triggering hypoglycemia. This interaction between TMP/SMX and repaglinide may have involved inhibition of CYP2C8 by trimethoprim. Clinicians should be aware that this association may lead to symptomatic hypoglycemia, particularly in patients with renal dysfunction.

Design, synthesis, and application of the trimethoprim-based chemical tag for live-cell imaging.

PubMed

Jing, Chaoran; Cornish, Virginia W

2013-01-01

Over the past decade, chemical tags have been developed to complement the use of fluorescent proteins in live-cell imaging. Chemical tags retain the specificity of protein labeling achieved with fluorescent proteins through genetic encoding, but provide smaller, more robust tags and modular use of organic fluorophores with high photon output and tailored functionalities. The trimethoprim-based chemical tag (TMP-tag) was initially developed based on the high affinity interaction between E. coli dihydrofolate reductase and the antibiotic trimethoprim and was subsequently rendered covalent and fluorogenic via proximity-induced protein labeling reactions. To date, the TMP-tag is one of the few chemical tags that enable intracellular protein labeling and high-resolution live-cell imaging. Here we describe the general design, chemical synthesis, and application of TMP-tag for live-cell imaging. Alternate protocols for synthesizing and using the covalent and the fluorogenic TMP-tags are also included. © 2013 by John Wiley & Sons, Inc.

Spectroscopic and spectrofluorimetric studies on the interaction of albendazole and trimethoprim with iodine

NASA Astrophysics Data System (ADS)

Ganesh, K.; Elango, K. P.

Raman, UV-vis, FT-IR, and fluorescence spectral techniques were employed to investigate the mechanism of interaction of albendazole (ALB) and trimethoprim (TMP) drugs with iodine. Interactions of ALB and TMP with iodine yields triiodide ion and its formation was confirmed by electronic and Raman spectra. The peaks appeared in Raman spectra of the isolated products are at around 145, 113 and 82 cm-1 are assigned to νas(I-I), νs(I-I) and δ(I3-) respectively, confirmed the presence of I3- ion. Formation constant (K), molar extinction coefficient (ɛ) and thermodynamic properties ΔH#, ΔS# and ΔG# were determined and discussed. Fluorescence quenching studies indicated that the interaction between the ALB, TMP with iodine are spontaneous and the TMP-iodine interaction is found to be stronger than that the other system. Solvent variation studies indicated that the binding constant increased with an increase in polarity of the medium.

Fluorescent Trimethoprim Conjugate Probes To Assess Drug Accumulation in Wild Type and Mutant Escherichia coli

PubMed Central

2016-01-01

Reduced susceptibility to antimicrobials in Gram-negative bacteria may result from multiple resistance mechanisms, including increased efflux pump activity or reduced porin protein expression. Up-regulation of the efflux pump system is closely associated with multidrug resistance (MDR). To help investigate the role of efflux pumps on compound accumulation, a fluorescence-based assay was developed using fluorescent derivatives of trimethoprim (TMP), a broad-spectrum synthetic antibiotic that inhibits an intracellular target, dihydrofolate reductase (DHFR). Novel fluorescent TMP probes inhibited eDHFR activity with comparable potency to TMP, but did not kill or inhibit growth of wild type Escherichia coli. However, bactericidal activity was observed against an efflux pump deficient E. coli mutant strain (ΔtolC). A simple and quick fluorescence assay was developed to measure cellular accumulation of the TMP probe using either fluorescence spectroscopy or flow cytometry, with validation by LC-MS/MS. This fluorescence assay may provide a simple method to assess efflux pump activity with standard laboratory equipment. PMID:27737551

Preconditioning of bone marrow-derived mesenchymal stromal cells by tetramethylpyrazine enhances cell migration and improves functional recovery after focal cerebral ischemia in rats.

PubMed

Li, Lin; Chu, Lisheng; Fang, Yan; Yang, Yan; Qu, Tiebing; Zhang, Jianping; Yin, Yuanjun; Gu, Jingjing

2017-05-12

Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) is one of the new therapeutic strategies for treating ischemic stroke. However, the relatively poor migratory capacity of BMSCs toward infarcted regions limited the therapeutic potential of this approach. Pharmacological preconditioning can increase the expression of CXC chemokine receptor 4 (CXCR4) in BMSCs and enhance cell migration toward the injury site. In the present study, we investigated whether tetramethylpyrazine (TMP) preconditioning could enhance BMSCs migration to the ischemic brain and improve functional recovery through upregulating CXCR4 expression. BMSCs were identified by flow cytometry analysis. BMSCs migration was evaluated in vitro by transwell migration assay, and CXCR4 expression was measured by quantitative reverse transcription-polymerase chain reaction and western blot analysis. In rats with focal cerebral ischemia, the neurological function was evaluated by the modified neurological severity score, the adhesive removal test and the corner test. The homing BMSCs and angiogenesis were detected by immunofluorescence, and expression of stromal cell-derived factor-1 (SDF-1) and CXCR4 was measured by western blot analysis. Flow cytometry analysis demonstrated that BMSCs expressed CD29 and CD90, but not CD34 and CD45. TMP pretreatment dose-dependently induced BMSCs migration and CXCR4 expression in vitro, which was significantly inhibited by AMD3100, a CXCR4 antagonist. In rat stroke models, we found more TMP-preconditioned BMSCs homing toward the infarcted regions than nonpreconditioned cells, leading to improved neurological performance and enhanced angiogenesis. Moreover, TMP-preconditioned BMSCs significantly upregulated the protein expression of SDF-1 and CXCR4 in the ischemic boundary regions. These beneficial effects of TMP preconditioning were blocked by AMD3100. TMP preconditioning enhances the migration and homing ability of BMSCs, increases CXCR4 expression, promotes angiogenesis, and improves neurological performance. Therefore, TMP preconditioning may be an effective strategy to improve the therapeutic potency of BMSCs for ischemic stroke due to enhanced BMSCs migration to ischemic regions.

Antibiotic-resistant Escherichia coli in women with acute cystitis in Canada

PubMed Central

McIsaac, Warren J; Moineddin, Rahim; Meaney, Christopher; Mazzulli, Tony

2013-01-01

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMX) has been a traditional first-line antibiotic treatment for acute cystitis; however, guidelines do not recommend TMP-SMX in regions where Escherichia coli resistance exceeds 20%. While resistance is increasing, there are no recent Canadian estimates from a primary care setting to guide prescribing decisions. METHODS: A total of 330 family physicians assessed 752 women with suspected acute cystitis between 2009 and 2011. Physicians documented clinical features and collected urine for cultures for 430 (57.2%) women. The proportion of resistant isolates of E coli and exact binomial 95% CIs were estimated nationally, and compared regionally and demographically. These estimates were compared with those from a 2002 national study. RESULTS: The proportion of TMP-SMX-resistant E coli was 16.0% nationally (95% CI 11.3% to 21.8%). This was not statistically higher than 2002 (10.9% [P=0.14]). TMP-SMX resistance was increased in women ≤50 years of age (21.4%) compared with older women (10.7% [P=0.037]). In women with no antibiotic exposure in the previous three months, TMP-SMX-resistant E coli remained more prevalent in younger women (21.8%) compared with older women (4.4% [P=0.003]). The proportion of ciprofloxacin-resistant E coli was 5.5% nationally (95% CI 2.7% to 9.9%), and was increased compared with 2002 (1.1% [P=0.036]). Ciprofloxacin resistance was highest in British Columbia (17.7%) compared with other regions (2.7% [P=0.003]), and was increased compared with 2002 levels in this province (0.0% [P=0.025]). Nitrofurantoin-resistant E coli levels were low (0.5% [95% CI 0.01% to 2.7%). DISCUSSION: The proportion of TMP-SMX-resistant E coli causing acute cystitis in women in Canada remains below 20% nationally, but may exceed this level in premenopausal women. Ciprofloxacin resistance has increased, notably in British Columbia. Nitrofurantoin resistance levels are low across the country. These observations indicate that TMP-SMX and nitrofurantoin remain appropriate empirical antibiotic agents for treating cystitis in primary care settings in Canada. PMID:24421825

Effect of Thermomechanical Processing on the Microstructure and Mechanical Properties of Nb-Ti-V Microalloyed Steel

NASA Astrophysics Data System (ADS)

Opiela, M.

2014-09-01

The paper presents the results of thermomechanical treatment via forging on the microstructure and mechanical properties of newly obtained microalloyed steel containing 0.28% C, 1.41% Mn, 0.027% Nb, 0.028% Ti, and 0.019% V. The investigated steel is assigned to the production of forged elements for the automotive industry. Conditions of forging using the thermomechanical processing method were developed based on plastometric tests. Continuous and double-hit compression tests were conducted using the Gleeble 3800 thermomechanical simulator. The samples were investigated in a temperature range from 900 to 1100 °C and a strain rate of 1 and 10 s-1. To determine the recrystallization kinetics of plastically deformed austenite, discontinuous compression tests of samples using the applied deformation were conducted in a temperature range from 900 to 1100 °C with isothermal holding of the specimens between successive deformations for 2-100 s. Observations of the microstructures of thin foils were conducted using a TITAN80-300 FEI transmission electron microscope. The applied thermomechanical treatment allows to obtain a fine-grained microstructure of the austenite during hot-working and production of forged parts. These acquire advantageous mechanical properties and guaranteed crack resistance after controlled cooling from the end plastic deformation temperature and successive tempering. Forgings produced using the thermomechanical treatment method, consecutively subjected to tempering in a temperature range from 550 to 650 °C, reveal values of YS0.2 which equal from 994 to 892 MPa, UTS from 1084 to 958 MPa, KV from 69 to 109 J, KV-40 from 55 to 83 J, and a hardness ranging from 360 to 300 HBW.

Effect of Different Thermomechanical Processes on the Microstructure, Texture, and Mechanical Properties of API 5L X70 Steel

NASA Astrophysics Data System (ADS)

Masoumi, Mohammad; Echeverri, Edwan Anderson Ariza; Silva, Cleiton Carvalho; Béreš, Miloslav; de Abreu, Hamilton Ferreira Gomes

2018-03-01

A commercial API 5L X70 steel plate was subjected to different thermomechanical processes to propose a novel thermomechanical rolling path to achieve improved mechanical properties. Scanning electron microscopy, electron backscatter diffraction, and x-ray texture analysis were employed for microstructural characterization. The results showed that strain-free recrystallized {001} ferrite grains that developed at higher rolling temperature could not meet the American Petroleum Institute (API) requirements. Also, refined and work-hardened grains that have formed in the intercritical region with high stored energy do not provide suitable tensile properties. However, fine martensite-austenite constituents dispersed in ferrite matrix with grains having predominantly {111} and {110} orientations parallel to the normal direction that developed under isothermal rolling at 850 °C provided an outstanding combination of tensile strength and ductility.

23 CFR 630.1012 - Project-level procedures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1012 Project-level procedures. (a) This section provides guidance and establishes procedures for States to manage the work zone impacts of individual projects. (b) Transportation Management Plan (TMP). A TMP consists of strategies to manage the work zone...

23 CFR 630.1012 - Project-level procedures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1012 Project-level procedures. (a) This section provides guidance and establishes procedures for States to manage the work zone impacts of individual projects. (b) Transportation Management Plan (TMP). A TMP consists of strategies to manage the work zone...

23 CFR 630.1012 - Project-level procedures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1012 Project-level procedures. (a) This section provides guidance and establishes procedures for States to manage the work zone impacts of individual projects. (b) Transportation Management Plan (TMP). A TMP consists of strategies to manage the work zone...

23 CFR 630.1012 - Project-level procedures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1012 Project-level procedures. (a) This section provides guidance and establishes procedures for States to manage the work zone impacts of individual projects. (b) Transportation Management Plan (TMP). A TMP consists of strategies to manage the work zone...

Finding an Optimal Thermo-Mechanical Processing Scheme for a Gum-Type Ti-Nb-Zr-Fe-O Alloy

NASA Astrophysics Data System (ADS)

Nocivin, Anna; Cojocaru, Vasile Danut; Raducanu, Doina; Cinca, Ion; Angelescu, Maria Lucia; Dan, Ioan; Serban, Nicolae; Cojocaru, Mirela

2017-09-01

A gum-type alloy was subjected to a thermo-mechanical processing scheme to establish a suitable process for obtaining superior structural and behavioural characteristics. Three processes were proposed: a homogenization treatment, a cold-rolling process and a solution treatment with three heating temperatures: 1073 K (800 °C), 1173 K (900 °C) and 1273 K (1000 °C). Results of all three proposed processes were analyzed using x-ray diffraction and scanning electron microscopy imaging, to establish and compare the structural modifications. The behavioural status was completed with micro-hardness and tensile strength tests. The optimal results were obtained for solution treatment at 1073 K.

Remineralizing Potential of a Low Fluoride Toothpaste with Sodium Trimetaphosphate: An in situ Study.

PubMed

Takeshita, Eliana M; Danelon, Marcelle; Castro, Luciene P; Cunha, Robson F; Delbem, Alberto C B

2016-01-01

To evaluate the effect of a low-fluoride (F) toothpaste supplemented with sodium trimetaphosphate (TMP) on enamel remineralization in situ. Bovine enamel blocks were selected on the basis of their surface hardness (SH) after caries-like lesions had been induced, and randomly divided into 4 treatment groups, according to the toothpastes used: without F or TMP (placebo); 500 ppm F; 500 ppm F plus 1% TMP; and 1,100 ppm F. The study design was blinded and crossover and performed in 4 phases of 3 days each. Eleven subjects used palatal appliances containing 4 bovine enamel blocks which were treated 3 times per day during 1 min each time, with natural slurries of saliva and toothpaste formed in the oral cavity during toothbrushing. After each phase, the percentages of surface (%SHR) and subsurface hardness recovery (%ΔKHNR) were calculated. F, calcium (Ca), and phosphorus (Pi) contents in enamel were also determined. Data were analyzed by 1-way, repeated-measures ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). Toothpaste with 500 ppm F + TMP and 1,100 ppm F showed similar %SHR and %ΔKHNR as well as enamel F, Ca, and Pi concentrations. The addition of TMP to a low-fluoride toothpaste promoted a similar remineralizing capacity to that of a standard (1,100 ppm F) toothpaste in situ. © 2016 S. Karger AG, Basel.

Bicarbonate-dependent, carbonate radical anion-driven tocopherol-mediated human LDL peroxidation: an in vitro and in vivo study.

PubMed

Lapenna, Domenico; Ciofani, Giuliano; Cuccurullo, Chiara; Neri, Matteo; Giamberardino, Maria Adele; Cuccurullo, Franco

2012-11-01

We have here investigated possible occurrence of bicarbonate-dependent, carbonate radical anion (CO(3)(•-))-driven tocopherol-mediated human LDL peroxidation (TMP) in vitro and in vivo. CO(3)(•-), generated in vitro by the SOD1/H(2)O(2)/bicarbonate system, readily promoted TMP, which was dependent on α-tocopherol and bicarbonate concentrations, and was inhibited by the CO(3)(•-) scavenger ethanol; moreover, TMP induced in vitro by the SOD1/H(2)O(2)/bicarbonate system occurred in the presence of α-tocopherol that typically underwent slow oxidative consumption. In the in vivo clinical setting, we showed that, compared to controls, hypertensive patients with diuretic-induced metabolic alkalosis and heightened blood bicarbonate concentration had lipid hydroperoxide burden and decreased α-tocopherol content in the LDL fraction, with direct significant correlation between the LDL levels of α-tocopherol and those of lipid hydroperoxides; remarkably, after resolution of metabolic alkalosis, together with normalization of blood bicarbonate concentration, the LDL content of lipid hydroperoxides was decreased and that of α-tocopherol augmented significantly. These findings suggest bicarbonate-dependent, CO(3)(•-)-driven LDL TMP in vivo. In conclusion, the present study highlights the occurrence of bicarbonate-dependent, CO(3)(•-)-driven human LDL TMP, the role of which in pathological conditions such as atherosclerosis warrants, however, further investigation.

Atovaquone versus trimethoprim-sulfamethoxazole as Pneumocystis jirovecii pneumonia prophylaxis following renal transplantation.

PubMed

Gabardi, Steven; Millen, Peter; Hurwitz, Shelley; Martin, Spencer; Roberts, Keri; Chandraker, Anil

2012-01-01

Pneumocystis pneumonia (PCP) is associated with significant morbidity and mortality in renal transplant recipients (RTR). Trimethoprim-sulfamethoxazole (TMP-SMZ) is considered the prophylactic agent-of-choice. Some patients require an alternative owing to TMP-SMZ intolerance. This is the first evaluation of full-dose atovaquone vs. TMP-SMZ for PCP prevention in RTR. One hundred and eighty-five RTR were evaluated in this single-center, retrospective analysis. Patients received either single-strength TMP-SMZ daily (group I; n = 160) or 1500 mg/d of atovaquone and of a fluoroquinolone for one month (group II; n = 25). The primary endpoint was the incidence of PCP at 12 months post-transplant. There were no cases of PCP in either group. There were comparable rates of infections from bacterial pathogens and cytomegalovirus, but rates of BK viremia were significantly higher in group I (22.5%) vs. group II (4%; p = 0.03). The incidence of leukopenia was similar in both groups. Higher mean potassium levels were seen in group I at three months post-transplant but were comparable at all other time points. The need for dose reduction and/or premature discontinuation of therapy secondary to adverse events was more prevalent in TMP-SMZ-treated patients. In our experience, atovaquone appears to be effective in preventing PCP post-renal transplant and also demonstrates good tolerability. © 2012 John Wiley & Sons A/S.

Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency.

PubMed

Lopez-Gomez, Carlos; Levy, Rebecca J; Sanchez-Quintero, Maria J; Juanola-Falgarona, Martí; Barca, Emanuele; Garcia-Diaz, Beatriz; Tadesse, Saba; Garone, Caterina; Hirano, Michio

2017-05-01

Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2 -/- ) mice by 2- to 3-fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: (1) deoxynucleosides might be the major active agents and (2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. To test these hypotheses, we assessed two therapies in Tk2 -/- mice: (1) dT+dC and (2) coadministration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2 -/- animals compared to dCMP+dTMP. Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652. © 2017 American Neurological Association.

Design and Technical Validation of a Telemedicine Service for Rural Healthcare in Ecuador.

PubMed

Vasquez-Cevallos, Leonel A; Bobokova, Jana; González-Granda, Patricia V; Iniesta, José M; Gómez, Enrique J; Hernando, M Elena

2017-12-12

Telemedicine is becoming increasingly important in Ecuador, especially in areas such as rural primary healthcare and medical education. Rural telemedicine programs in the country need to be strengthened by means of a technological platform adapted to local surroundings and offering advantages such as access to specialized care, continuing education, and so on, combined with modest investment requirements. This present article presents the design of a Telemedicine Platform (TMP) for rural healthcare services in Ecuador and a preliminary technical validation with medical students and teachers. An initial field study was designed to capture the requirements of the TMP. In a second phase, the TMP was validated in an academic environment along three consecutive academic courses. Assessment was by means of user polls and analyzing user interactions as registered automatically by the platform. The TMP was developed using Web-based technology and open code software. One hundred twenty-four students and 6 specialized faculty members participated in the study, conducting a total of 262 teleconsultations of clinical cases and 226 responses, respectively. The validation results show that the TMP is a useful communication tool for the documentation and discussion of clinical cases. Moreover, its usage may be recommended as a teaching methodology, to strengthen the skills of medical undergraduates. The results indicate that implementing the system in rural healthcare services in Ecuador would be feasible.

Continuous recrystallization during thermomechanical processing of a superplastic Al-10Mg-0.1Zr alloy

NASA Technical Reports Server (NTRS)

Hales, S. J.; Mcnelley, T. R.; Crooks, R.

1990-01-01

Microstructural evolution via static continuous recrystallization during thermomechanical processing of an Al-Mg-Zr alloy is addressed. Mechanical property data demonstrated that as-rolled material was capable of superplastic response without further treatment. Further, superplastic ductility at 300 C was enhanced by a factor of five by increasing the reheating time between rolling passes during processing also at 300 C. This enhanced ductility was associated with a Cu-texture and a microstructure consisting of predominantly high-angle boundaries. Processing to minimize recovery resulted in a strong Brass-texture component, a predominantly low-angle boundary microstructure and poorer ductility.

Microstructure, Mechanical Properties, and Corrosion Resistance of Thermomechanically Processed AlZn6Mg0.8Zr Alloy

PubMed Central

Kowalski, Aleksander; Ozgowicz, Wojciech; Jurczak, Wojciech; Grajcar, Adam; Boczkal, Sonia; Żelechowski, Janusz

2018-01-01

The paper presents results of the investigations on the effect of low-temperature thermomechanical treatment (LTTT) on the microstructure of AlZn6Mg0.8Zr alloy (7000 series) and its mechanical properties as well as electrochemical and stress corrosion resistance. For comparison of the LTTT effect, the alloy was subjected to conventional precipitation hardening. Comparative studies were conducted in the fields of metallographic examinations and static tensile tests. It was found that mechanical properties after the LTTT were better in comparison to after conventional heat treatment (CHT). The tested alloy after low-temperature thermomechanical treatment with increasing plastic deformation shows decreased electrochemical corrosion resistance during potentiodynamic tests. The alloy after low-temperature thermomechanical treatment with deformation degree in the range of 10 to 30% is characterized by a high resistance to stress corrosion specified by the level of PSCC indices. PMID:29642448

Submerged anaerobic membrane bioreactor for wastewater treatment and energy generation.

PubMed

Bornare, J B; Adhyapak, U S; Minde, G P; Kalyan Raman, V; Sapkal, V S; Sapkal, R S

2015-01-01

Compared with conventional wastewater treatment processes, membrane bioreactors (MBRs) offer several advantages including high biodegradation efficiency, excellent effluent quality and smaller footprint. However, it has some limitations on account of its energy intensive operation. In recent years, there has been growing interest in use of anaerobic membrane bioreactors (AnMBRs) due to their potential advantages over aerobic systems, which include low sludge production and energy generation in terms of biogas. The aim of this study was to evaluate the performance of a submerged AnMBR for the treatment of synthetic wastewater having 4,759 mg/l chemical oxygen demand (COD). The COD removal efficiency was over 95% during the performance evaluation study. Treated effluent with COD concentration of 231 mg/l was obtained for 25.5 hours hydraulic retention time. The obtained total organic carbon concentrations in feed and permeate were 1,812 mg/l and 89 mg/l, respectively. An average biogas generation and yield were 25.77 l/d and 0.36 m3/kg COD, respectively. Evolution of trans-membrane pressure (TMP) as a function of time was studied and an average TMP of 15 kPa was found suitable to achieve membrane flux of 12.17 l/(m2h). Almost weekly back-flow chemical cleaning of the membrane was found necessary to control TMP within the permissible limit of 20 kPa.

Significant biological role of Sp1 transactivation in multiple myeloma

PubMed Central

Fulciniti, Mariateresa; Amin, Samir; Nanjappa, Puru; Rodig, Scott; Prabhala, Rao; Li, Cheng; Minvielle, Stephane; Tai, Yu-tzu; Tassone, Pierfrancesco; Avet-Loiseau, Herve; Hideshima, Teru; Anderson, Kenneth C.; Munshi, Nikhil C.

2015-01-01

Purpose The transcription factor Sp1 controls number of cellular processes by regulating the expression of critical cell cycle, differentiation and apoptosis-related genes containing proximal GC/GT-rich promoter elements. We here provide both experimental and clinical evidence that Sp1 plays an important regulatory role in MM cell growth and survival. Experimental design We have investigated the functional Sp1 activity in MM cells using a plasmid with renilla luciferase reporter gene driven by Sp1-responsive promoter. We have also used both SiRNA and ShRNA-mediated Sp1 knock-down to investigate the growth and survival effects of Sp1 on MM cells, and further investigated the anti-MM activity of Terameprocol (TMP), a small molecule which specifically competes with Sp1-DNA binding in vitro and in vivo. Results We have confirmed high Sp1 activity in MM cells which is further induced by adhesion to bone marrow stromal cells (BMSC). Sp1 knock down decreases MM cell proliferation and induces apoptosis. Sp1-DNA binding inhibition by TMP inhibits MM cell growth both in vitro and in vivo, inducing caspase 9-dependent apoptosis and overcoming the protective effects of BMSCs. Conclusions Our results demonstrate Sp1 as an important transcription factor in myeloma that can be therapeutically targeted for clinical application by TMP. PMID:21856768

Influence of gas-liquid two-phase flow on angiotensin-I converting enzyme inhibitory peptides separation by ultra-filtration.

PubMed

Charoenphun, Narin; Youravong, Wirote

2017-01-01

Membrane fouling is a major problem in ultra-filtration systems and two-phase flow is a promising technique for permeate flux enhancement. The objective of this research was to study the use of an ultra-filtration (UF) system to enrich angiotensin-I converting enzyme (ACE) inhibitory peptides from tilapia protein hydrolysate. To select the most appropriate membrane and operating condition, the effects of membrane molecular weight cut-off (MWCO), transmembrane pressure (TMP) and cross-flow velocity (CFV) on permeate flux and ACE inhibitory peptide separation were studied. Additionally, the gas-liquid two-phase flow technique was applied to investigate its effect on the process capability. The results showed that the highest ACE inhibitory activity was obtained from permeate of the 1 kDa membrane. In terms of TMP and CFV, the permeate flux tended to increase with TMP and CFV. The use of gas-liquid two-phase flow as indicated by shear stress number could reduce membrane fouling and increase the permeate flux up to 42%, depending on shear stress number. Moreover, the use of a shear stress number of 0.039 led to an augmentation in ACE inhibitory activity of permeates. Operating conditions using a shear stress number of 0.039 were recommended for enrichment of ACE inhibitory peptides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Thermomechanical Modeling of Shape Memory Alloys and Applications

NASA Astrophysics Data System (ADS)

Lexcellent, C.; Leclercq, S.

The aim of the present paper is a general macroscopic description of the thermomechanical behavior of shape memory alloys (SMA). We use for framework the thermodynamics of irreversible processes. This model is efficient for describing the behavior of "smart" structures as a bronchial, a tentacle element and an prosthesis hybrid structure made of Ti Ni SMA wires embedded in a resin epoxy matrix.

Closer insight into the reactivity of TMP-dialkyl zincates in directed ortho-zincation of anisole: experimental evidence of amido basicity and structural elucidation of key reaction intermediates.

PubMed

Clegg, William; Conway, Ben; Hevia, Eva; McCall, Matthew D; Russo, Luca; Mulvey, Robert E

2009-02-18

The new dialkyl(aryl) lithium zincates [(THF)(2)Li(C(6)H(4)-OMe)MeZnMe] (4), [(TMEDA)Li(C(6)H(4)-OMe)MeZnMe] (6), [(THF)(3)Li(C(6)H(4)-OMe)(t)BuZn(t)Bu] (7), and [(PMDETA)Li(C(6)H(4)-OMe)(t)BuZn(t)Bu] (8) have been prepared by co-complexation reactions of lithiated anisole with the relevant dialkylzinc compound and the relevant Lewis base. These new heterobimetallic compounds have been characterized in solution using (1)H, (13)C{H}, and (7)Li NMR spectroscopy, and the molecular structures of 6 and 8 have been elucidated by X-ray crystallography. In 6 the distinct metals are connected through the anisole ligand which binds in an ambidentate fashion (through carbon-zinc and oxygen-lithium contacts) and also through one of the methyl groups, to close a [LiOCCZnC] six-membered ring; whereas 8 displays an open structure where anisole connects the two metals (in the same mode as in 6) but with the tert-butyl groups exclusively bonded terminally to zinc. Reactivity studies of zincates 4 and 7 with the amine TMP(H) supply experimental evidence that these heterobimetallic compounds are intermediates in the two-step deprotonation reaction of anisole by TMP-dialkyl zincates and show the relevance of the alkyl groups in the efficiency of TMP-dialkyl zincate bases. In addition, important solvent effects have also been evaluated. When hexane is added to THF solutions of compounds 4 or 7, the homoleptic tetraorganozincate [(THF)(2)Li(2)Zn(C(6)H(4)-OMe)(4)] (5) is obtained as the result of a disproportionation process. This lithium-rich zincate has also been spectroscopically and crystallographically characterized.

15 CFR 740.9 - Temporary imports, exports, reexports, and transfers (in-country) (TMP).

Code of Federal Regulations, 2014 CFR

2014-01-01

... commodities and software may be placed in a bonded warehouse or a storage facility provided that the exporter... the end of the beta test period as defined by the software producer or, if the software producer does... software. (a) Temporary exports, reexports, and transfers (in-country). License Exception TMP authorizes...

Derivative spectrum chromatographic method for the determination of trimethoprim in honey samples using an on-line solid-phase extraction technique.

PubMed

Uchiyama, Kazuhisa; Kondo, Mari; Yokochi, Rika; Takeuchi, Yuri; Yamamoto, Atsushi; Inoue, Yoshinori

2011-07-01

A simple, selective and rapid analytical method for determination of trimethoprim (TMP) in honey samples was developed and validated. This method is based on a SPE technique followed by HPLC with photodiode array detection. After dilution and filtration, aliquots of 500 μL honey samples were directly injected to an on-line SPE HPLC system. TMP was extracted on an RP SPE column, and separated on a hydrophilic interaction chromatography column during HPLC analysis. At the first detection step, the noise level of the photodiode array data was reduced with two-dimensional equalizer filtering, and then the smoothed data were subjected to derivative spectrum chromatography. On the second-derivative chromatogram at 254 nm, the limit of detection and the limit of quantification of TMP in a honey sample were 5 and 10 ng/g, respectively. The proposed method showed high accuracy (60-103%) with adequate sensitivity for TMP monitoring in honey samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

MIP-graphene-modified glassy carbon electrode for the determination of trimethoprim.

PubMed

da Silva, Hélder; Pacheco, João G; Magalhães, Júlia M C S; Viswanathan, Subramanian; Delerue-Matos, Cristina

2014-02-15

A novel sensitive electrochemical sensor was developed by electropolymerization of pyrrole (PY) and molecularly imprinted polymer (MIP) which was synthesized onto a glassy carbon electrode (GCE) in aqueous solution using cyclic voltammetry in the presence of Trimethoprim (TMP) as template molecules. Furthermore, a previous electrode modification was performed by deposition of a suspension of graphene on the electrode's surface. The performance of the imprinted and non-imprinted (NIP) films was evaluated by impedance spectroscopy (EIS) and cyclic voltammetry (CV) of a ferric solution. The molecularly imprinted film exhibited a high selectivity and sensitivity toward TMP. The sensor presented a linear range, between peak current intensity and logarithm of TMP concentration between 1.0 × 10(-6) and 1.0 × 10(-4)M. The results were accurate (with recoveries higher than 94%), precise (with standard deviations less than 5%) and the detection limit was 1.3 × 10(-7)M. The new sensor is selective, simple to construct and easy to operate. The MIP sensor was successfully applied to quantify TMP in urine samples. © 2013 Elsevier B.V. All rights reserved.

Correlations between trans-membrane pressure (TMP) and sludge properties in submerged membrane electro-bioreactor (SMEBR) and conventional membrane bioreactor (MBR).

PubMed

Hasan, Shadi W; Elektorowicz, Maria; Oleszkiewicz, Jan A

2012-09-01

The influence of sludge properties in SMEBR and conventional MBR pilot systems on membrane fouling was investigated. Generated data were analyzed using statistical analysis Pearson's product momentum correlation coefficient (r(p)). Analysis showed that TMP had strong direct (r(p)=0.9182) and inverse (r(p)=-0.9205) correlations to mean particle size diameter in MBR and SMEBR, respectively. TMP in SMEBR had a strong direct correlation to the sludge mixed liquor suspended solids concentration (MLSS) (r(p)=0.7757) while a weak direct correlation (r(p)=0.1940) was observed in MBR. SMEBR showed a moderate inverse correlation (r(p)=-0.6118) between TMP and soluble carbohydrates (EPS(c)) and a very weak direct correlation (r(p)=0.3448) to soluble proteins (EPS(p)). Conversely, EPS(p) in MBR had more significant impact (r(p)=0.4856) on membrane fouling than EPS(c) (r(p)=0.3051). The results provide insight into optimization of operational conditions in SMEBR system to overcome membrane fouling. Copyright © 2012 Elsevier Ltd. All rights reserved.

High-performance liquid chromatography method for the simultaneous determination of sulfamethoxazole and trimethoprim in bovine milk using an on-line clean-up column.

PubMed

Pereira, A V; Cass, Q B

2005-11-05

A bidimensional HPLC method for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in bovine milk has been developed and validated. After centrifugation, aliquots (150 microl) of milk samples were directly injected to a column-switching HPLC system. At the first step a RAM octyl-BSA column was employed to automatically remove proteins that otherwise would interfere with milk analysis. The mobile phase 0.01 M phosphate buffer pH 6.0:acetonitrile (95:5, v/v) was used in the first 5 min for the elution of milk proteins and then 0.01 M phosphate buffer pH 6.0:acetonitrile (83:17, v/v) for transfer SMX and TMP to the analytical column. The separation of SMX and TMP from one another and from other remaining milk components was performed on an octyl column using the mobile phase 0.01 M phosphate buffer pH 5.0:acetonitrile (82:18, v/v), which were detected by UV at 265 nm. The calibration graphs were linear in the concentration ranges of 25-800 ng/ml and 50-400 ng/ml for SMX and TMP, respectively. The intra- and inter-assay coefficients of variation were less than 15% for both drugs. The validated method was applied to the analysis of milk samples of twelve (two groups of six) cows after administration (intramuscular or subcutaneous) of a single recommended therapeutic dose of the SMX-TMP combination.

A systematic and mechanistic evaluation of aspartic acid as filler for directly compressed tablets containing trimethoprim and trimethoprim aspartate.

PubMed

ElShaer, Amr; Hanson, Peter; Mohammed, Afzal R

2013-04-01

The generally accepted paradigm of 'inert' and 'mono functional' excipient in dosage form has been recently challenged with the development of individual excipients capable of exhibiting multiple functions (e.g. binder-disintegrants, surfactant which affect P-gp function). The proposed study has been designed within the realm of multifunctionality and is the first and novel investigation towards evaluation of aspartic acid as a filler and disintegration enhancing agent for the delivery of biopharmaceutical class IV model drug trimethoprim. The study investigated powder characteristics using angle of repose, laser diffractometry and scanning electron microscopy (SEM). The prepared tablets were characterised using Heckel analysis, disintegration time and tensile strength measurements. Although Heckel analysis revealed that both TMP and TMP aspartate salt have high elasticity, the salt form produced a stronger compact which was attributed to the formation of agglomerates. Aspartic acid was found to have high plasticity, but its incorporation into the formulations was found to have a negative impact on the compaction properties of TMP and its salt. Surface morphology investigations showed that mechanical interlocking plays a vital role in binding TMP crystals together during compaction, while the small particle size of TMP aspartate agglomerates was found to have significant impact on the tensile strength of the tablets. The study concluded that aspartic acid can be employed as filler and disintegrant and that compactability within tablets was independent of the surface charge of the excipients. Copyright © 2012 Elsevier B.V. All rights reserved.

Tetramethylpyrazine attenuates TNF-α-induced iNOS expression in human endothelial cells: Involvement of Syk-mediated activation of PI3K-IKK-IκB signaling pathways

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

Zheng, Zhen; Li, Zhiliang; Chen, Song

2013-08-15

Endothelial cells produce nitric oxide (NO) by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NO synthase (iNOS). We explored the effect of tetramethylpyrazine (TMP), a compound derived from chuanxiong, on tumor necrosis factor (TNF)-α-induced iNOS in human umbilical vein endothelial cells (HUVECs) and explored the signal pathways involved by using RT-PCR and Western blot. TMP suppressed TNF-α-induced expression of iNOS by inhibiting IκB kinase (IKK) phosphorylation, IκB degradation and nuclear factor κB (NF-κB) nuclear translocation, which were required for NO gene transcription. Exposure to wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression, suggesting activation of such a signal pathwaymore » might be phosphoinositide-3-kinase (PI3K) dependent. Spleen tyrosine kinase (Syk) inhibitor piceatannol significantly inhibited NO production. Furthermore, piceatannol obviously suppressed TNF-α-induced IκB phosphorylation and the downstream NF-κB activation, suggesting that Syk is an upstream key regulator in the activation of PI3K/IKK/IκB-mediated signaling. TMP significantly inhibited TNF-α-induced phosphorylation of Syk and PI3K. Our data indicate that TMP might repress iNOS expression, at least in part, through its inhibitory effect of Syk-mediated PI3K phosphorylation in TNF-α-stimulated HUVECs. -- Highlights: •TMP suppressed TNF-α-induced expression of iNOS by inhibiting IKK/IκB/NF-κB pathway. •PI3K inhibitor wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression. •Syk inhibitor piceatannol repressed PI3K/IKK/IκB mediated NO production. •Syk is an upstream regulator in the activation of PI3K/IKK/IκB-mediated signaling. •TMP might repress iNOS expression through Syk-mediated PI3K pathway.« less

Enhancing hatch rate and survival in laboratory-reared hybrid Devils Hole Pupfish through application of antibiotics to eggs and larvae

USGS Publications Warehouse

Feuerbacher, Olin; Bonar, Scott A.; Barrett, Paul J.

2017-01-01

We evaluated the effectiveness of four antibiotics in enhancing the hatch rate, larval survival, and adult survival of hybrid Devils Hole Pupfish Cyprinodon diabolis (hybridized with Ash Meadows Amargosa Pupfish C. nevadensis mionectes). Cephalexin (CEX; concentration = 6.6 mg/L of water), chloramphenicol (CAM; 50 mg/L), erythromycin (ERY; 12.5 mg/L), and trimethoprim sulfamethoxazole (TMP-SMX; 25 mg/L) were applied as a constant bath either to incubating eggs or to larvae that hatched from untreated eggs. Hatch rate was roughly doubled by incubation in the presence of CAM (68% hatch) and TMP-SMX (66%) relative to the control (28%). Cephalexin and ERY conferred no benefit upon the hatch rate. Among fry that hatched from treated eggs, there was no increase in 15-d larval survival. However, fish that hatched from eggs treated with CAM, ERY, and TMP-SMX demonstrated enhanced survival at 360 d (51.2, 38.4, and 43.6%, respectively) and at 540 d (22.6, 6.8, and 20.2%, respectively); the untreated control had no survivors to those time points. All groups of eggs treated with antibiotics showed reductions in bacterial colony-forming units (CFUs) at 24 h posttreatment. At 120 h posttreatment, CEX-treated eggs had CFU counts similar to those of the control, whereas the TMP-SMX-treated eggs had the lowest CFU counts. Eggs treated with CAM and ERY had similar CFU counts, which were significantly reduced from the control counts. Larvae that were treated with CAM and TMP-SMX within 12 h posthatch showed enhanced 15-d survival (74% and 72%, respectively) in comparison with the control (56%). For pupfish rearing efforts in which antibiotic use is appropriate, CAM and TMP-SMX appear to provide the greatest benefit, particularly when applied to incubating eggs rather than to hatched larvae.

Crystal Structures of Wild-type and Mutant Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase Reveal an Alternative Conformation of NADPH that may be Linked to Trimethoprim Resistance

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

Frey, K.; Liu, J; Lombardo, M

2009-01-01

Both hospital- and community-acquired Staphylococcus aureus infections have become major health concerns in terms of morbidity, suffering and cost. Trimethoprim-sulfamethoxazole (TMP-SMZ) is an alternative treatment for methicillin-resistant S. aureus (MRSA) infections. However, TMP-resistant strains have arisen with point mutations in dihydrofolate reductase (DHFR), the target for TMP. A single point mutation, F98Y, has been shown biochemically to confer the majority of this resistance to TMP. Using a structure-based approach, we have designed a series of novel propargyl-linked DHFR inhibitors that are active against several trimethoprim-resistant enzymes. We screened this series against wild-type and mutant (F98Y) S. aureus DHFR and foundmore » that several are active against both enzymes and specifically that the meta-biphenyl class of these inhibitors is the most potent. In order to understand the structural basis of this potency, we determined eight high-resolution crystal structures: four each of the wild-type and mutant DHFR enzymes bound to various propargyl-linked DHFR inhibitors. In addition to explaining the structure-activity relationships, several of the structures reveal a novel conformation for the cofactor, NADPH. In this new conformation that is predominantly associated with the mutant enzyme, the nicotinamide ring is displaced from its conserved location and three water molecules complete a network of hydrogen bonds between the nicotinamide ring and the protein. In this new position, NADPH has reduced interactions with the inhibitor. An equilibrium between the two conformations of NADPH, implied by their occupancies in the eight crystal structures, is influenced both by the ligand and the F98Y mutation. The mutation induced equilibrium between two NADPH-binding conformations may contribute to decrease TMP binding and thus may be responsible for TMP resistance.« less

Probing Lipid Bilayers under Ionic Imbalance.

PubMed

Lin, Jiaqi; Alexander-Katz, Alfredo

2016-12-06

Biological membranes are normally under a resting transmembrane potential (TMP), which originates from the ionic imbalance between extracellular fluids and cytosols, and serves as electric power storage for cells. In cell electroporation, the ionic imbalance builds up a high TMP, resulting in the poration of cell membranes. However, the relationship between ionic imbalance and TMP is not clearly understood, and little is known about the effect of ionic imbalance on the structure and dynamics of biological membranes. In this study, we used coarse-grained molecular dynamics to characterize a dipalmitoylphosphatidylcholine bilayer system under ionic imbalances ranging from 0 to ∼0.06 e charges per lipid (e/Lip). We found that the TMP displayed three distinct regimes: 1) a linear regime between 0 and 0.045 e/Lip, where the TMP increased linearly with ionic imbalance; 2) a yielding regime between ∼0.045 and 0.060 e/Lip, where the TMP displayed a plateau; and 3) a poration regime above ∼0.060 e/Lip, where we observed pore formation within the sampling time (80 ns). We found no structural changes in the linear regime, apart from a nonlinear increase in the area per lipid, whereas in the yielding regime the bilayer exhibited substantial thinning, leading to an excess of water and Na + within the bilayer, as well as significant misalignment of the lipid tails. In the poration regime, lipid molecules diffused slightly faster. We also found that the fluid-to-gel phase transition temperature of the bilayer dropped below the normal value with increased ionic imbalances. Our results show that a high ionic imbalance can substantially alter the essential properties of the bilayer, making the bilayer more fluid like, or conversely, depolarization of a cell could in principle lead to membrane stiffening. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Crystallographic Analysis Reveals a Novel Second Binding Site for Trimethoprim in Active Site Double Mutants of Human Dihydrofolate Reductase†,‡

PubMed Central

Cody, Vivian; Pace, Jim; Piraino, Jennifer; Queener, Sherry F.

2011-01-01

In order to produce a more potent replacement for trimethoprim (TMP) used as a therapy for Pneumocystis pneumonia and targets dihydrofolate reductase from Pneumocystis jirovecii (pjDHFR), it is necessary to understand the determinants of potency and selectivity against DHFR from the mammalian host and fungal pathogen cells. To this end, active site residues in human (h)DHFR were replaced with those from pjDHFR. Structural data are reported for two complexes of TMP with the double mutants Gln35Ser/Asn64Phe (Q35S/N64F) and Gln35Lys/Asn64Phe (Q35K/N64F) of hDHFR that unexpectedly show evidence for the binding of two molecules of TMP: one molecule that binds in the normal folate binding site and the second molecule that binds in a novel subpocket site such that the mutated residue Phe64 is involved in van der Waals contacts to the trimethoxyphenyl ring of the second TMP molecule. Kinetic data for the binding of TMP to hDHFR and pjDHFR reveal an 84-fold selectivity of TMP against pjDHFR (Ki 49 nM) compared to hDHFR (Ki 4093 nM). Two mutants that contain one substitution from pj- and one from the closely related Pneumocystis carinii DHFR (pcDHFR) (Q35K/N64F and Q35S/N64F) show Ki values of 593 and 617 nM, respectively; these Ki values are well above both the Ki for pjDHFR and are similar to pcDHFR (Q35K/N64F) and Q35S/N64F) (305 nM). These results suggest that active site residues 35 and 64 play key roles in determining selectivity for pneumocystis DHFR, but that other residues contribute to the unique binding of inhibitors to these enzymes. PMID:21684339

Incidence of Hyponatremia with High-Dose Trimethoprim-Sulfamethoxazole Exposure.

PubMed

Tsapepas, Demetra; Chiles, Mariana; Babayev, Revekka; Rao, Maya K; Jaitly, Manasvi; Salerno, David; Mohan, Sumit

2016-12-01

Trimethoprim-sulfamethoxazole (TMP-SMX) is a commonly prescribed antibiotic used at high doses for treatment of pneumocystis pneumonia and other infections. Trimethoprim is structurally related to the potassium-sparing diuretic amiloride and has been associated with hyperkalemia and hyponatremia through blocking of epithelial sodium channels in the distal nephron. The incidence of hyponatremia in hospitalized patients treated with high-dose TMP-SMX is unknown. We performed a single-center retrospective chart review of all hospitalized patients who received high-dose TMP-SMX (n = 235) from January 2012 to July 2014. Patients with congestive heart failure, cirrhosis, estimated glomerular filtration rate <30 mL/min/1.73 m 2 , baseline hyponatremia, and those on other medications associated with hyponatremia were excluded. Hyponatremia was defined as a serum sodium level <136 mEq/L. Analysis was restricted to 76 unique patients who received more than 8 mg/kg/d of TMP for ≥3 days. Mean starting serum sodium at time of TMP-SMX initiation was 138.4 ± 2.1 mEq/L. Fifty-five patients (72.3%) developed hyponatremia while on therapy, of which 43.6% (n = 24) were cases of serum sodium <130 mEq/L. Mean sodium at the time of nadir was 131.6 ± 5.1 mEq/L. Hyponatremia was noted, on average, 5.5 days after initiation of therapy, with more severe hyponatremia development among African American patients. Urine sodium concentrations were available for 40.0% (22/55) of incident hyponatremia cases, with mean urinary sodium of 104.8 ± 55.9 mEq/L. Hyponatremia often resolved within 3 weeks of drug discontinuation. There is a high incidence (72.3%) of hyponatremia associated with the use of high-dose TMP-SMX among hospitalized patients. This is an overlooked and potentially reversible cause of hyponatremia. Copyright © 2016 Elsevier Inc. All rights reserved.

Influences of Thermomechanical Processing on the Microstructure and Mechanical Properties of a HSLA Steel

NASA Astrophysics Data System (ADS)

Zhao, Yu; Xu, Songsong; Zou, Yun; Li, Jinhui; Zhang, Z. W.

High strength low alloy (HSLA) steels with high strength, high toughness, good corrosion resistance and weldability, can be widely used in shipbuilding, automobile, construction, bridging industry, etc. The microstructure evolution and mechanical properties can be influenced by thermomechanical processing. In this study, themomechanical processing is optimized to control the matrix microstructure and nano-scale precipitates in the matrix simultaneously. It is found that the low-temperature toughness and ductility of the steels are significantly the matrix microstructure during enhancing the strength by introducing the nano-scale precipitates. The effects of alloying elements on the microstructure evolution and nano-scale precipitation are also discussed.

A Software Assurance Framework for Mitigating the Risks of Malicious Software in Embedded Systems Used in Aircraft

DTIC Science & Technology

2011-09-01

to show cryptographic signature # generation on a UNIX system # SHA=/bin/ sha256 CSDB=/tmp/csdb CODEBASE=. touch "$CSDB" find "$CODEBASE" -type f...artifacts generated earlier. 81 #! /bin/sh # # Demo program to show cryptographic signature # verification on a UNIX system # SHA=/bin/ sha256 CSDB=/tmp

ICF Gamma-Ray measurements on the NIF

NASA Astrophysics Data System (ADS)

Herrmann, Hans; Kim, Y.; Hoffman, N. M.; Batha, S. H.; Stoeffl, W.; Church, J. A.; Sayre, D. B.; Liebman, J. A.; Cerjan, C. J.; Carpenter, A. C.; Grafil, E. M.; Khater, H. Y.; Horsfield, C. J.; Rubery, M.

2013-10-01

The primary objective of the NIF Gamma Reaction History (GRH) diagnostic is to provide bang time and burn width information in order to constrain implosion simulation parameters such as shell velocity and confinement time. This is accomplished by measuring DT fusion gamma-rays with energy-thresholded Gas Cherenkov detectors that convert MeV gamma-rays into UV/visible photons for high-bandwidth optical detection. Burn-weighted CH ablator areal density is also inferred based on measurement of the 12C(n,n') gammas emitted at 4.44 MeV from DT neutrons inelastically scattering off carbon nuclei as they pass through the plastic ablator. This requires that the four independent GRH gas cells be set to differing Cherenkov thresholds (e.g., 2.9, 4.5, 8 & 10 MeV) in order to be able to unfold the primary spectral components predicted to be in the gamma ray energy spectrum (i.e., DT γ 27Al & 28Si (n,n') γ from the thermo-mechanical package (TMP); and 12C(n,n' γ from the ablator). The GRH response to 12C(n,n') γ is calibrated in-situ by placing a known areal density of carbon in the form of a puck placed ~6 cm from a DT exploding pusher implosion. Comparisons between inferred gamma fluences and simulations based on the nuclear cross sections databases will be presented. Supported by US DOE NNSA.

Development and Characterization of Improved NiTiPd High-Temperature Shape-Memory Alloys by Solid-Solution Strengthening and Thermomechanical Processing

NASA Technical Reports Server (NTRS)

Bigelow, Glen; Noebe, Ronald; Padula, Santo, II; Garg, Anita; Olson, David

2006-01-01

The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently motivating research in high-temperature shape-memory alloys (HTSMA) with transformation temperatures greater than 100 C. One of the basic high-temperature alloys investigated to fill this need is Ni(19.5)Ti(50.5)Pd30. Initial testing has indicated that this alloy, while having acceptable work characteristics, suffers from significant permanent deformation (or ratcheting) during thermal cycling under load. In an effort to overcome this deficiency, various solid-solution alloying and thermomechanical processing schemes were investigated. Solid-solution strengthening was achieved by substituting 5at% gold or platinum for palladium in Ni(19.5)Ti(50.5)Pd30, the so-called baseline alloy, to strengthen the martensite and austenite phases against slip processes and improve thermomechanical behavior. Tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared. The relative difference in yield strength between the martensite and austenite phases and the dimensional stability of the alloy were improved by the quaternary additions, while work output was only minimally impacted. The three alloys were also thermomechanically processed by cycling repeatedly through the transformation range under a constant stress. This so-called training process dramatically improved the dimensional stability in these samples and also recovered the slight decrease in work output caused by quaternary alloying. An added benefit of the solid-solution strengthening was maintenance of enhanced dimensional stability of the trained material to higher temperatures compared to the baseline alloy, providing a greater measure of over-temperature capability.

Implementation and Evaluation of Technology Mentoring Program Developed for Teacher Educators: A 6M-Framework

ERIC Educational Resources Information Center

Gunuc, Selim

2015-01-01

The purpose of this basic research is to determine the problems experienced in the Technology Mentoring Program (TMP), and the study discusses how these problems affect the process in general. The implementation was carried out with teacher educators in the education faculty. 8 doctorate students (mentors) provided technology mentoring…

Trimethoprim/sulfamethoxazole-induced phenytoin toxicity in the elderly: a population-based study

PubMed Central

Antoniou, Tony; Gomes, Tara; Mamdani, Muhammad M; Juurlink, David N

2011-01-01

AIMS Pharmacokinetic studies suggest that trimethoprim (TMP) can inhibit the hepatic metabolism of phenytoin, but the clinical relevance of this is uncertain. We studied the risk of phenytoin toxicity following the prescription of trimethoprim/sulfamethoxazole (TMP/SMX), a commonly used antibiotic, among elderly patients receiving phenytoin. METHODS We conducted a population-based, nested case–control study of a cohort of Ontario residents aged 66 years of age or older treated with phenytoin over a 17-year period (April 1 1992 to March 31 2009). Within this group, case patients were those hospitalized with phenytoin toxicity. For each case, we identified up to four control patients from the same cohort, matched for age and sex, and determined the odds ratio (OR) for the association between phenytoin toxicity and receipt of TMP/SMX in the preceding 30 days. RESULTS Among 58 429 elderly patients receiving phenytoin during the study period, we identified 796 case patients hospitalized for phenytoin toxicity and 3148 matched controls. Following multivariable adjustment for potential confounders, we observed a more than doubling of the risk of phenytoin toxicity following the receipt of TMP/SMX [adjusted OR 2.11, 95% confidence interval (CI) 1.24, 3.60]. In contrast, we observed no such risk with amoxicillin, an antibiotic with similar indications but not expected to interact with phenytoin (adjusted OR 1.12, 95% CI 0.64, 1.98). CONCLUSION Among older patients receiving phenytoin, treatment with TMP/SMX is associated with a more than twofold increase in the risk of phenytoin toxicity. When clinically appropriate, alternate antibiotics should be considered for these patients. PMID:21395647

Structural characterization of molecular complexes formed by trimethoprim and cimitidine with 2,3,5,6-tetrachloro-1,4-benzoquinone

NASA Astrophysics Data System (ADS)

Balraj, C.; Ganesh, K.; Elango, K. P.

2011-07-01

Spectroscopic and spectrofluorimetric techniques have been employed to investigate the structure of the charge transfer (CT) complexes of Trimethoprim (TMP) and Cimitidine (CTD) drugs with 2,3,5,6-tetrachloro-1,4-benzoquinone ( p-chloranil, p-CHL). The stoichiometry of the complexes was found to be 1:2 for TMP- p-CHL system and 1:1 for CTD- p-CHL system. The thermodynamic results indicated that the formation of molecular complex between the donors and the acceptor is spontaneous and endothermic. The results of electronic spectral studies indicated that the formation constant for CTD- p-CHL system is found to be higher than that for TMP- p-CHL system. The observation is well supported by the results of fluorescence quenching studies and the association constants calculated for CTD- p-CHL system is 36.2 × 10 3 mol L -1 and that for TMP- p-CHL system is 2.6 × 10 3 mol L -1. The kinetic results, in both the cases, indicated that the interaction is first order each with respect to the concentration of the donor and the acceptor. The physico-chemical parameters viz. oscillator strength, dipole moment, ionization potential and dissociation energy of the complexes were also determined and discussed. Structural characterization of the complexes were done using FT-IR and 1H NMR spectral techniques and the results indicated that, in TMP, the free NH 2 group while in CTD the pyrazole N sbnd H moiety involves in complexation with the acceptor, p-CHL.

Bringing Joy through Dance: Community Outreach with the Council for Professional Recognition and the Trey McIntyre Project

ERIC Educational Resources Information Center

Dombrink-Green, Meghan

2011-01-01

In May 2011, the Council for Professional Recognition and the contemporary ballet troupe the Trey McIntyre Project (TMP) combined their passion for community outreach by bringing TMP dancers to perform for young children who are hospitalized in the Washington, D.C., area. The Council for Professional Recognition, which administers the Child…

Treatment of brucellosis in a young child with trimethoprim/sulfamethoxazole anaphylaxis.

PubMed

Teker, Demet; Tanir, Gonul; Ozmen, Serap; Teke, Turkan Aydın; Keles, Sennur; Bostancı, Ilknur

2014-01-01

Brucellosis is a common zoonotic disease throughout the world. Brucella spp. transmit to humans through contact with fluids of infected animals, especially sheep, cattle, and goats. It is also transmitted by ingestion of fluid-derived products of infected animals, such as unpasteurized milk and cheese. Brucella spp. changes pH level of intracellular environment, so the first treatment approach is to administer antibiotics that have activity in acidic conditions. Anti-brucellosis treatment regimens include doxycycline for children older than eight years old and rifampicin and trimethoprim/sulfamethoxazole (TMP-SMX) combination therapy for children under eight years old, which may be able to act intracellularly under acidic conditions. A TMP-SMX allergy causing anaphylaxis has been reported previously. No alternative anti-brucellosis treatments have been reported in the literature for patients under eight years old with a TMP-SMX allergy. Here, we report a case of a child with brucellosis and a TMP-SMX allergy who was under eight years old at the time of diagnosis and was successfully treated with rifampicin, ciprofloxacin, and gentamicin. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

General One-Pot Synthesis of Transition-Metal Phosphide/Nitrogen-Doped Carbon Hybrid Nanosheets as Ultrastable Anodes for Sodium-Ion Batteries.

PubMed

Li, Jingjing; Shi, Liang; Gao, Jingyu; Zhang, Genqiang

2018-01-26

Sodium-ion batteries (SIBs) have been considered as promising energy storage devices in grid-level applications, owing to their largely reduced cost compared with that of lithium-ion batteries. However, the practical application of SIBs has been seriously hindered because of the lack of appropriate anode materials, limited by the thermodynamics perspective, which is one of the central task at current stage. Herein, we have developed a general one-pot strategy for the synthesis of transition-metal phosphide (TMP) based hybrid nanosheets composed of carbon-coated TMP nanoparticles anchored to the surface of nitrogen-doped carbon nanosheets. This facile and cost-effective method is quite universal and holds potential to be further extended to other metal phosphide materials. Significantly, the hybrid nanosheet electrode possesses excellent sodium storage properties as anodes for SIBs, including high specific capacity, an ultra-long cycle life and a remarkable rate performance. This work makes a significant contribution to not only the synthetic methodology of TMP-carbon two-dimensional hybrid nanostructures, but also the application of TMP-based anodes for high-energy SIBs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

UV-Vis spectroscopic study and DFT calculation on the solvent effect of trimethoprim in neat solvents and aqueous mixtures.

PubMed

Almandoz, M C; Sancho, M I; Duchowicz, P R; Blanco, S E

2014-08-14

The solvatochromic behavior of trimethoprim (TMP) was analyzed using UV-Vis spectroscopy and DFT methods in neat and binary aqueous solvent mixtures. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions on the absorption maxima were evaluated by means of the linear solvation energy relationship concept of Kamlet and Taft. This analysis indicated that both interactions play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra of TMP and TMP:(solvent)n complexes in ACN and H2O using TD-DFT methods were in agreement with the experimental ones. Binary aqueous mixtures containing as co-solvents DMSO, ACN and EtOH were studied. Preferential solvation was detected as a nonideal behavior of the wavenumber curve respective to the analytical mole fraction of co-solvent in all binary systems. TMP molecules were preferentially solvated by the organic solvent over the whole composition range. Index of preferential solvation, as well as the influence of solvent parameters were calculated as a function of solvent composition. Copyright © 2014 Elsevier B.V. All rights reserved.

Thermomagnetic processing of liquid-crystalline epoxy resins and their mechanical characterization using nanoindentation.

PubMed

Li, Yuzhan; Rios, Orlando; Kessler, Michael R

2014-11-12

A thermomagnetic processing method was used to produce a biphenyl-based liquid-crystalline epoxy resin (LCER) with oriented liquid-crystalline (LC) domains. The orientation of the LCER was confirmed and quantified using two-dimensional X-ray diffraction. The effect of molecular alignment on the mechanical and thermomechanical properties of the LCER was investigated using nanoindentation and thermomechanical analysis, respectively. The effect of the orientation on the fracture behavior was also examined. The results showed that macroscopic orientation of the LC domains was achieved, resulting in an epoxy network with an anisotropic modulus, hardness, creep behavior, and thermal expansion.

[Photodrugtherapy of psoriasis with oral psoralen and black light therapy].

PubMed

Corrales Padilla, H

1975-01-01

Oral 4, 5', 8 trimethoxypsoralen (TMP) or 8-M-methoxypsoralen (8 MP) plus black light therapy of psoriasis produced disappearing of lesions in 6 out of 8 pacients treated with TMP and in 6 out of 7 treated with 8 MP. In three patients treated with the first drug, a paired comparision demonstrated that the ingestion of it, when followed of black exposure, is more effective than the exposure to conventional ultraviolet light. Parrish et al. have shown this for oral methoxalen and long wave ultraviolet light. Combined TMP or 8-MP and black light therapy inhibits epidermal DNA synthesis and this is the scientific base of its application in the therapy of psoriasis, disease in which an accelerated celular cicle and DNA synthesis has been postulated.

Role of segregation and precipitates on interfacial strengthening mechanisms in metal matrix composites when subjected to thermo-mechanical processing

NASA Astrophysics Data System (ADS)

Myriounis, Dimitrios

Metal Matrix ceramic-reinforced composites are rapidly becoming strong candidates as structural materials for many high temperatures and aerospace applications. Metal matrix composites combine the ductile properties of the matrix with a brittle phase of the reinforcement, leading to high stiffness and strength with a reduction in structural weight. The main objective of using a metal matrix composite system is to increase service temperature or improve specific mechanical properties of structural components by replacing existing superalloys.The satisfactory performance of metal matrix composites depends critically on their integrity, the heart of which is the quality of the matrix-reinforcement interface. The nature of the interface depends on the processing of the metal matrix composite component. At the micro-level the development of local stress concentration gradients around the ceramic reinforcement, as the metal matrix attempts to deform during processing, can be very different to the nominal conditions and play a crucial role in important microstructural events such as segregation and precipitation at the matrix-reinforcement interface. These events dominate the cohesive strength and subsequent mechanical properties of the interface.At present the relationship between the strength properties of metal matrix composites and the details of the thermo-mechanical forming processes is not well understood.The purpose of the study is to investigate several strengthening mechanisms and the effect of thermo-mechanical processing of SiCp reinforced A359 aluminium alloy composites on the particle-matrix interface and the overall mechanical properties of the material. From experiments performed on composite materials subjected to various thermo-mechanical conditions and by observation using SEM microanalysis and mechanical testing, data were obtained, summarised and mathematically/statistically analysed upon their significance.The Al/SiCp composites studied, processed in specific thermo-mechanical conditions in order to attain higher values of interfacial fracture strength, due to precipitation hardening and segregation mechanisms, also exhibited enhanced bulk mechanical and fracture resistant properties.An analytical model to predict the interfacial fracture strength in the presence of material segregation was also developed during this research effort. Its validity was determined based on the data gathered from the experiments.The tailoring of the properties due to the microstructural modification of the composites was examined in relation to the experimental measurements obtained, which define the macroscopical behaviour of the material.

Inventory of File prob.sref.cluster1.f03.grib2

Science.gov Websites

Records: 6 Number Level/Layer Parameter Forecast Valid Description 001 2 m above ground TMP 3 hour fcst Temperature [prob] prob >293 002 2 m above ground TMP 3 hour fcst Temperature [prob] prob <273 003 surface CRAIN 3 hour fcst Categorical Rain [prob] prob =1 004 surface CFRZR 3 hour fcst Categorical

A pharmacokinetic and residual study of sulfadiazine/trimethoprim in mandarin fish (Siniperca chuatsi) with single- and multiple-dose oral administrations.

PubMed

Wang, W; Luo, L; Xiao, H; Zhang, R; Deng, Y; Tan, A; Jiang, L

2016-06-01

A pharmacokinetic and tissue residue study of sulfadiazine combined with trimethoprim (SDZ/TMP = 5/1) was conducted in Siniperca chuatsi after single- (120 mg/kg) or multiple-dose (an initial dose of 120 mg/kg followed by a 5-day consecutive dose of 60 mg/kg) oral administrations at 28 °C. The absorption half-life (t1/2α ), elimination half-life (t1/2β ), volume of distribution (Vd /F), and the total body clearance (ClB /F) for SDZ and TMP were 4.3 ± 1.7 to 6.3 ± 1.8 h and 2.4 ± 1.0 to 3.9 ± 0.9 h, 25.9 ± 4.5 to 53.0 ± 5.6 h and 11.8 ± 3.5 to 17.1 ± 3.4 h, 2.34 ± 0.78 to 3.67 ± 0.99 L/kg and 0.39 ± 0.01 to 1.33 ± 0.57 L/kg, and 0.03 ± 0.01 to 0.06 ± 0.01 L/kg·h and 0.02 ± 0.01 to 0.05 ± 0.01 L/kg·h, respectively, after the single dose. The elimination half-life (t1/2β ) and mean residue time (MRT) for SDZ and TMP were 68.8 ± 7.8 to 139.8 ± 12.3 h and 34.0 ± 5.5 to 56.1 ± 6.8 h, and 99.3 ± 6.1 to 201.7 ± 11.5 h and 49.1 ± 3.5 to 81.0 ± 5.1 h, respectively, after the multiple-dose administration. The daily oral SDZ/TMP administration might cause a high tissue concentration and long t1/2β , thereby affecting antibacterial activity. The withdrawal time for this oral SDZ/TMP formulation (according to the accepted guidelines in Europe for maximum residue limits, <0.1 mg/kg of tissues for sulfonamides, and <0.05 mg/kg for TMP) should not be <36 days for fish. © 2015 John Wiley & Sons Ltd.

Performance evaluation of cross-flow membrane system for wastewater reuse from the wood-panels industry.

PubMed

Dizge, Nadir

2014-01-01

The objectives of this investigation were to perform a series of lab-scale membrane separation experiments under various operating conditions to investigate the performance behaviour of nanofiltration membrane (NF 270) for wastewater reuse from the wood-panels industry. The operating condition effects, e.g. cross-flow velocity (CFV), trans membrane pressure (TMP) and temperature, on the permeate flux and contaminant rejection efficiency were investigated. Moreover, three different samples: (1) raw wastewater collected from the wood-panels industry; (2) ultrafiltration pre-treated wastewater (UF-NF); and (3) coagulation/flocculation pre-treated wastewater (CF-NF) were employed in this study. The UF-NF was proposed as a pre-treatment process because it could reduce the chemical oxygen demand (COD) effectively with lower energy consumption than CF-NF. The performance of NF 270 membrane was assessed by measurements of the many parameters (pH, conductivity, total dissolved solids, COD, suspended solids, total nitrogen, nitrite, nitrate, and total phosphate) under various operating conditions. It was noted that the contaminant rejection was affected by changing TMP and CFV. It was concluded that the purified water stream can be recycled into the process for water reuse or safely disposed to the river.

Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

DOE PAGES

Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

2016-02-23

Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment (TMT) process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 to 1173 K (700 to 900ºC) was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/andmore » above 1073 K (800 ºC). Relatively low volume fraction of M 23C 6 precipitates was observed after processing at 1073 K (800 ºC). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine grained heat affected zone (FGHAZ) region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard “normalization and tempering” processes. Lastly, the steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room-temperature toughness. The above data is also analysed based on existing theories of creep deformation based on dislocation climb mechanism.« less

Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

NASA Astrophysics Data System (ADS)

Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

2016-05-01

Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 K to 1173 K (700 °C to 900 °C), was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/and above 1073 K (800 °C). Relatively low volume fraction of M23C6 precipitates was observed after processing at 1073 K (800 °C). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine-grained heat-affected zone region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard "normalization and tempering" processes. The steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room temperature toughness. The above data are also analyzed based on existing theories of creep deformation based on dislocation climb mechanism.

Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

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

Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment (TMT) process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 to 1173 K (700 to 900ºC) was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/andmore » above 1073 K (800 ºC). Relatively low volume fraction of M 23C 6 precipitates was observed after processing at 1073 K (800 ºC). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine grained heat affected zone (FGHAZ) region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard “normalization and tempering” processes. Lastly, the steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room-temperature toughness. The above data is also analysed based on existing theories of creep deformation based on dislocation climb mechanism.« less

MreB-Dependent Organization of the E. coli Cytoplasmic Membrane Controls Membrane Protein Diffusion.

PubMed

Oswald, Felix; Varadarajan, Aravindan; Lill, Holger; Peterman, Erwin J G; Bollen, Yves J M

2016-03-08

The functional organization of prokaryotic cell membranes, which is essential for many cellular processes, has been challenging to analyze due to the small size and nonflat geometry of bacterial cells. Here, we use single-molecule fluorescence microscopy and three-dimensional quantitative analyses in live Escherichia coli to demonstrate that its cytoplasmic membrane contains microdomains with distinct physical properties. We show that the stability of these microdomains depends on the integrity of the MreB cytoskeletal network underneath the membrane. We explore how the interplay between cytoskeleton and membrane affects trans-membrane protein (TMP) diffusion and reveal that the mobility of the TMPs tested is subdiffusive, most likely caused by confinement of TMP mobility by the submembranous MreB network. Our findings demonstrate that the dynamic architecture of prokaryotic cell membranes is controlled by the MreB cytoskeleton and regulates the mobility of TMPs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Multi-Response Optimization of Process Parameters for Imidacloprid Removal by Reverse Osmosis Using Taguchi Design.

PubMed

Genç, Nevim; Doğan, Esra Can; Narcı, Ali Oğuzhan; Bican, Emine

2017-05-01

  In this study, a multi-response optimization method using Taguchi's robust design approach is proposed for imidacloprid removal by reverse osmosis. Tests were conducted with different membrane type (BW30, LFC-3, CPA-3), transmembrane pressure (TMP = 20, 25, 30 bar), volume reduction factor (VRF = 2, 3, 4), and pH (3, 7, 11). Quality and quantity of permeate are optimized with the multi-response characteristics of the total dissolved solid (TDS), conductivity, imidacloprid, and total organic carbon (TOC) rejection ratios and flux of permeate. The optimized conditions were determined as membrane type of BW30, TMP 30 bar, VRF 3, and pH 11. Under these conditions, TDS, conductivity, imidacloprid, and TOC rejections and permeate flux were 97.50 97.41, 97.80, 98.00% and 30.60 L/m2·h, respectively. Membrane type was obtained as the most effective factor; its contribution is 64%. The difference between the predicted and observed value of multi-response signal/noise (MRSN) is within the confidence interval.

Current treatment of ocular toxoplasmosis in immunocompetent patients: A network meta-analysis.

PubMed

Zhang, Yanxia; Lin, Xiao; Lu, Fangli

2018-04-25

Ocular toxoplasmosis (OT) is the most frequent form of infectious posterior uveitis caused by the protozoan parasite Toxoplasma gondii. To evaluate the available evidence in peer-reviewed publications about the most effective therapy for OT in immunocompetent patients, herein a systematic literature search was conducted using Embase, PubMed, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) database from January 1987 to October 2017, with search terms "OT", "retinochoroiditis", "treatment", and "immunocompetent"; search filters "controlled clinical trial", "randomized clinical trial", and "clinical trial". The included studies were performed to evaluate the various treatment modalities of OT. Different treatment regimens were compared with regard to the improvement of visual acuity, the resolution of vitreous inflammation, recurrence, and side-effects. We independently extracted data and assessed eligibility and risk of bias using the preferred reporting items for systematic reviews and meta-analysis, and resolved any disagreement through discussion. A Bayesian network meta-analysis model was used to evaluate the interesting outcomes of all the interventions. Total 10 trials of treatments for OT were found to meet the inclusion criteria. Six trials of treatments including clindamycin, azithromycin, and trimethoprim-sulfamethoxazole (TMP-SMX) were compared with conventional therapy (the combination of pyrimethamine, sulfadiazine, and prednisone) for evaluation of the effect on visual acuity, vitreous inflammation, recurrence of OT, and side-effects. Two trials were compared TMP-SMX with placebo. One trial was compared azithromycin with TMP-SMX. And another trial was compared among treatments with clindamycin, P-S, TMP-SMX, and placebo. Based on our network meta-analysis, therapy with TMP-SMX seems to be an alternative treatment of OT in immunocompetent patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Cost-Effectiveness of Cranberries vs Antibiotics to Prevent Urinary Tract Infections in Premenopausal Women: A Randomized Clinical Trial

PubMed Central

Bosmans, Judith E.; Beerepoot, Mariëlle A. J.; Prins, Jan M.; ter Riet, Gerben; Geerlings, Suzanne E.

2014-01-01

Background Urinary tract infections (UTIs) are common and result in an enormous economic burden. The increasing prevalence of antibiotic-resistant microorganisms has stimulated interest in non-antibiotic agents to prevent UTIs. Objective To evaluate the cost-effectiveness of cranberry prophylaxis compared to antibiotic prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) over a 12 month period in premenopausal women with recurrent UTIs. Materials and Methods An economic evaluation was performed alongside a randomized trial. Primary outcome was the number of UTIs during 12 months. Secondary outcomes included satisfaction and quality of life. Healthcare utilization was measured using questionnaires. Missing data were imputed using multiple imputation. Bootstrapping was used to evaluate the cost-effectiveness of the treatments. Results Cranberry prophylaxis was less effective than TMP-SMX prophylaxis, but the differences in clinical outcomes were not statistically significant. Costs after 12 months in the cranberry group were statistically significantly higher than in the TMP-SMX group (mean difference €249, 95% confidence interval 70 to 516). Cost-effectiveness planes and cost-effectiveness acceptability curves showed that cranberry prophylaxis to prevent UTIs is less effective and more expensive than (dominated by) TMP-SMX prophylaxis. Conclusion In premenopausal women with recurrent UTIs, cranberry prophylaxis is not cost-effective compared to TMP-SMX prophylaxis. However, it was not possible to take into account costs attributed to increased antibiotic resistance within the framework of this randomized trial; modeling studies are recommended to investigate these costs. Moreover, although we based the dosage of cranberry extract on available evidence, this may not be the optimal dosage. Results may change when this optimal dosage is identified. Trial Registration ISRCTN.org ISRCTN50717094 PMID:24705418

The effect of probe choice and solution conditions on the apparent photoreactivity of dissolved organic matter.

PubMed

Maizel, Andrew C; Remucal, Christina K

2017-08-16

Excited triplet states of dissolved organic matter ( 3 DOM) are quantified directly with the species-specific probes trans,trans-hexadienoic acid (HDA) and 2,4,6-trimethylphenol (TMP), and indirectly with the singlet oxygen ( 1 O 2 ) probe furfuryl alcohol (FFA). Although previous work suggests that these probe compounds may be sensitive to solution conditions, including dissolved organic carbon concentration ([DOC]) and pH, and may quantify different 3 DOM subpopulations, the probes have not been systematically compared. Therefore, we quantify the apparent photoreactivity of diverse environmental waters using HDA, TMP, and FFA. By conducting experiments under ambient [DOC] and pH, with standardized [DOC] and pH, and with solid phase extraction isolates, we demonstrate that much of the apparent dissimilarity in photochemical measurements is attributable to solution conditions, rather than intrinsic differences in 3 DOM production. In general, apparent quantum yields (Φ 1 O 2 ≥ Φ 3 DOM,TMP ≫ Φ 3 DOM,HDA ) and pseudo-steady state concentrations ([ 1 O 2 ] ss > [ 3 DOM] ss,TMP > [ 3 DOM] ss,HDA ) show consistent relationships in all waters under standardized conditions. However, intrinsic differences in 3 DOM photoreactivity are apparent between DOM from diverse sources, as seen in the higher Φ 1 O 2 and lower Φ 3 DOM,TMP of wastewater effluents compared with oligotrophic lakes. Additionally, while conflicting trends in photoreactivity are observed under ambient conditions, all probes observe quantum yields increasing from surface wetlands to terrestrially influenced waters to oligotrophic lakes under standardized conditions. This work elucidates how probe selection and solution conditions influence the apparent photoreactivity of environmental waters and confirms that 3 DOM or 1 O 2 probes cannot be used interchangeably in waters that vary in [DOC], pH, or DOM source.

Determination of sulfadiazine, trimethoprim, and N(4) -acetyl-sulfadiazine in fish muscle plus skin by Liquid Chromatography-Mass Spectrometry. Withdrawal-time calculation after in-feed administration in gilthead sea bream (Sparus aurata L.) fed two different diets.

PubMed

Zonaras, V; Tyrpenou, A; Alexis, M; Koupparis, M

2016-10-01

This study presents a depletion study for sulfadiazine and trimethoprim in muscle plus skin of gilthead sea bream (Sparus aurata L.). N(4) -acetyl-sulfadiazine, the main metabolite of sulfadiazine (SDZ), was also examined. The fish were held in seawater at a temperature of 24-26 °C. SDZ and trimethoprim (TMP) were administered orally with medicated feed for five consecutive days at daily doses of 25 mg SDZ and 5 mg TMP per kg of fish body weight per day. Two different diets, fish oil- and plant oil-based diets, were investigated. Ten fish were sampled at each of the days 1, 3, 5, 6, 8, 9, 10, and 12 after the start of veterinary medicine administration. However for the calculation of the withdrawal periods, sampling day 1 was set as 24 h after the last dose of the treatment. Fish samples were analyzed for SDZ, TMP, and acetyl-sulfadiazine (AcSDZ) residues by liquid chromatography-mass spectrometry. SDZ and TMP concentrations declined rapidly from muscle plus skin. Considering a maximum residue limit of 100 μg/kg for the total of sulfonamides and 50 μg/kg for TMP residues in fish muscle plus skin, the withdrawal periods of the premix trimethoprim-sulfadiazine 50% were calculated as 5 and 6 days, at 24-26 °C, in fish oil (FO) and plant oil (PO) groups, respectively. The investigation of this work is important to protect consumers by controlling the undesirable residues in fish. © 2016 John Wiley & Sons Ltd.

Trimethoprim-sulfonamide Use during the First Trimester of Pregnancy and the Risk of Congenital Anomalies

PubMed Central

Hansen, Craig; Andrade, Susan E.; Freiman, Heather; Dublin, Sascha; Haffenreffer, Katie; Cooper, William O.; Cheetham, T.Craig; Toh, Sengwee; Li, De-Kun; Raebel, Marsha A.; Kuntz, Jennifer L.; Perrin, Nancy; Rosales, A.Gabriela; Carter, Shelley; Pawloski, Pamala A.; Maloney, Elizabeth M.; Graham, David J.; Sahin, Leyla; Scott, Pamela E.; Yap, John; Davis, Robert

2016-01-01

Background Sulfonamide antibacterials are widely used in pregnancy, but evidence about their safety is mixed. The objective of this study was to assess the association between first-trimester sulfonamide exposure and risk of specific congenital malformations. Methods Mother-infant pairs were selected from a cohort of 1.2 million liveborn deliveries (2001–2008) at 11 US health plans comprising the Medication Exposure in Pregnancy Risk Evaluation Program (MEPREP). Mothers with first-trimester trimethoprim-sulfonamide (TMP-SUL) exposures were randomly matched 1:1 to 1) a primary comparison group: mothers exposed to penicillins and/or cephalosporins, and 2) a secondary comparison group: mothers with no dispensing of an antibacterial, antiprotozoal, or antimalarial medication during the same time period. The outcomes were cardiovascular abnormalities, cleft palate/lip, clubfoot, and urinary tract abnormalities. Results We first identified 7,615 infants in the TMP-SUL exposure group, of which 7595 (99%) were exposed to a combination of TMP-SUL and the remaining 1% to sulfonamides alone. After matching (1:1) to the comparator groups and only including those with complete data on covariates there were 20,064 (n=6,688 per group) in the primary analyses. Overall, cardiovascular defects (1.52%) were the most common and cleft lip/palate (0.10%) the least common that were evaluated. Compared to penicillin/cephalosporin exposure, and no antibacterial exposure, TMP-SUL exposure was not associated with statistically significant elevated risks for cardiovascular, cleft lip/palate, clubfoot, or urinary system defects. Conclusions First trimester TMP-SUL exposure was not associated with a higher risk of the congenital anomalies studied, compared to exposure to penicillins and/or cephalosporins, or no exposure to antibacterials. PMID:26599424

Metaproteomic analysis of biocake proteins to understand membrane fouling in a submerged membrane bioreactor.

PubMed

Zhou, Zhongbo; Meng, Fangang; He, Xiang; Chae, So-Ryong; An, Yujia; Jia, Xiaoshan

2015-01-20

Metaproteomic analyses, including two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) separation and matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF)/TOF mass spectrometer (MS) detection, were used to trace and identify biocake proteins on membranes in a bench-scale submerged membrane bioreactor (MBR). 2D-PAGE images showed that proteins in the biocake (S3) at a low transmembrane pressure (TMP) level (i.e., before the TMP jump) had larger gray intensities in the pH 5.5–7.0 region regardless of the membrane flux, similar to soluble microbial product (SMP) proteins. However, the biocake (S2 and S4) at a high TMP level (i.e., after the TMP jump) had many more proteins in the pH range of 4.0–5.5, similar to extracellular polymeric substance (EPS) proteins. Such similarities between biocake proteins and SMP or EPS proteins can be useful for tracing the sources of proteins resulting in membrane fouling. In total, 183 differentially abundant protein spots were marked in the three biocakes (S2, S3, and S4). However, only 32 protein spots co-occurred in the 2D gels of the three biocakes, indicating that membrane fluxes and TMP evolution levels had significant effects on the abundance of biocake proteins. On the basis of the MS and MS/MS data, 23 of 71 protein spots were successfully identified. Of the 23 proteins, outer membrane proteins (Omp) were a major contributor (60.87%). These Omps were mainly from potential surface colonizers such as Aeromonas, Enterobacter, Pseudomonas, and Thauera. Generally, the metaproteomic analysis is a useful alternative to trace the sources and compositions of biocake proteins on the levels of molecules and bacteria species that can provide new insight into membrane fouling.

Antibodies to co-trimoxazole (trimethoprim and/or sulfamethoxazole) related to the presence of the drug in a commercial low-ionic-strength solution.

PubMed

Pham, Bach-Nga; Gien, Dominique; Bensaad, Farid; Babinet, Jérome; Dubeaux, Isabelle; Rouger, Philippe; Le Pennec, Pierre-Yves

2012-04-01

Drug-dependent antibodies have been associated with approximately 10% of acquired immune hemolytic anemia cases. These antibodies are a rare cause of interference in pretransfusion red blood cell (RBC) serologic testing. The aim of this work was to report three cases of subjects developing antibodies against co-trimoxazole, a combination of trimethoprim (TMP) and sulfamethoxazole (SMX). Blood samples of donor/patients were referred to our laboratory for the exploration of a positive antibody detection test. There was no recent history of drug taking. Antibody identification was performed by gel test using an indirect antiglobulin test, with reagent RBCs in low-ionic-strength solutions (LISS) containing co-trimoxazole or not. All three sera showed positive reactions when RBCs were resuspended in LISS containing co-trimoxazole, but negative reactions when RBCs were resuspended in LISS without antibiotic. We detected antibodies against co-trimoxazole showing three different antibody patterns: anti-TMP plus anti-SMX, anti-TMP alone, or anti-SMX alone. Anti-TMP showed an apparent anti-Ku specificity in the two cases where it was present. Anti-SMX showed an apparent anti-H specificity in one of the two cases described. The drug-dependent antibodies were not associated with acquired hemolytic anemia or other pathologies. Antibodies against co-trimoxazole may only be detected when using a diluent for reagent RBCs containing the drug in question. Antibody pattern (anti-TMP and/or anti-SMX) may vary according to individuals' immune response. Drug-dependent antibodies may react as antibodies against a high-prevalence antigen, supporting the hypothesis of antibodies to drug and membrane components. Drug-dependent antibodies such as anti-co-trimoxazole may be a serologic finding without clinical features. © 2011 American Association of Blood Banks.

Can the composition of the intestinal microbiota predict the development of urinary tract infections?

PubMed

den Heijer, Casper Dj; Geerlings, Suzanne E; Prins, Jan M; Beerepoot, Mariëlle Aj; Stobberingh, Ellen E; Penders, John

2016-10-01

To evaluate whether intestinal microbiota predicts the development of new-onset urinary tract infections (UTIs) in postmenopausal women with prior recurrent UTIs (rUTIs). Fecal samples (n = 40) originated from women with rUTI who received 12 months' prophylaxis of either trimethoprim-sulfamethoxazole (TMP-SMX) or lactobacilli. Microbial composition was assessed by 16S rRNA pyrosequencing. At baseline, fecal microbiota of women with zero and more than or equal to four UTIs during follow-up showed no significant differences. Only TMP-SMX prophylaxis resulted in reduced microbial diversity. Microbial structure of two samples from the same woman showed limited relatedness. In postmenopausal women with rUTI, the intestinal microbiota was not predictive for new-onset UTIs. Only TMP-SMX, and not lactobacilli, prophylaxis had effects on the microbial composition. Data in ENA:PRJEB13868.

The development and production of thermo-mechanically forged tool steel spur gears

NASA Technical Reports Server (NTRS)

Bamberger, E. N.

1973-01-01

A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

Research to Operations: The Critical Transition

NASA Technical Reports Server (NTRS)

Fogarty, Jennifer A.

2009-01-01

Space Life Sciences Directorate (SLSD) specializes in transitioning technology and knowledge to medical operations. This activity encompasses funding a spectrum of research and technology efforts, such as understanding fundamental biological mechanisms altered by microgravity and executing technology watches for state of the art diagnostic imaging equipment. This broad spectrum approach to fulfilling the need to protect crewmember health and performance during long and short duration missions to the International Space Station, moon and Mars is made possible by having a line of site between research and operations. Currently, SLSD's line of site is articulated in a transition to medical practice (TMP) process. This process is designed to shepherd information and knowledge gained through fundamental and mechanistic research toward the development of an operational solution such as a pre-flight selection criteria; an in-flight countermeasure, monitoring capability or treatment; or a post-flight reconditioning program. The TMP process is also designed to assist with the customization of mature hardware or technology for NASA specific use. The benefits of this process are that the concept of operational usability is interjected early in the research, design, or acquisition phase, and stakeholders are involved early to identify requirements and also periodically asked to assess requirements compliance of research or technology development project. Currently a device known as the actiwatch is being assessed for the final transition to operational use. Specific examples of research to operations transition success help to illustrate the process and bolster communication between the research and medical operations communities.

Inventory of File nam.t00z.awipak00.tm00.grib2

Science.gov Websites

Rime Factor [non-dim] 009 1 hybrid level HGT analysis Geopotential Height [gpm] 010 1 hybrid level TMP [kg/kg] 040 30 mb SNMR analysis Snow Mixing Ratio [kg/kg] 041 30 mb RIME analysis Rime Factor [non-dim Factor [non-dim] 054 75 mb HGT analysis Geopotential Height [gpm] 055 75 mb TMP analysis Temperature [K

Lubricant Foaming and Aeration Study. Part 2.

DTIC Science & Technology

1985-12-01

phosphate. The blend 0-77-10, composed of tmp-heptanoate plus neopentyl glycol esters, tested in the same way and with the same combination of solutes at...the same concentrations, showed about half the foaminess of the unblended tmp-heptanoate. The neopentyl glycol esters are, therefore, less...substituent methyl groups in a solute confer profoaming activity in these neopentyl glycol esters as solvents. Also, not forgotten, is that the

Inventory of File nam.t00z.smartconus06.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 6 hour fcst Dew Point Temperature [K] 003 surface SPFH 6 hour fcst Specific Index [K] 027 surface HINDEX 6 hour fcst Haines Index [Numeric] 028 surface TMP 5 hour fcst Temperature [K] 029 surface TMP 4 hour fcst Temperature [K] 030 surface DPT 5 hour fcst Dew Point Temperature [K

Inventory of File gfs.t06z.smartguam12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific Best (4 layer) Lifted Index [K] 020 surface TMP 11 hour fcst Temperature [K] 021 surface TMP 10 hour fcst Temperature [K] 022 surface DPT 11 hour fcst Dew Point Temperature [K] 023 surface DPT 10 hour

Inventory of File nam.t00z.smartak06.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 6 hour fcst Dew Point Temperature [K] 003 surface SPFH 6 hour fcst Specific Haines Index [Numeric] 029 surface TMP 5 hour fcst Temperature [K] 030 surface TMP 4 hour fcst Temperature [K] 031 surface DPT 5 hour fcst Dew Point Temperature [K] 032 surface DPT 4 hour fcst Dew Point

Inventory of File nam.t00z.smartconus12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific hour fcst Haines Index [Numeric] 030 surface TMP 11 hour fcst Temperature [K] 031 surface TMP 10 hour fcst Temperature [K] 032 surface DPT 11 hour fcst Dew Point Temperature [K] 033 surface DPT 10 hour

The relationship between crystal structure and methyl and t-butyl group dynamics in van der Waals organic solids

NASA Astrophysics Data System (ADS)

Beckmann, Peter A.; Paty, Carol; Allocco, Elizabeth; Herd, Maria; Kuranz, Carolyn; Rheingold, Arnold L.

2004-03-01

We report x-ray diffractometry in a single crystal of 2-t-butyl-4-methylphenol (TMP) and low-frequency solid state nuclear magnetic resonance (NMR) proton relaxometry in a polycrystalline sample of TMP. The x-ray data show TMP to have a monoclinic, P21/c, structure with eight molecules per unit cell and two crystallographically inequivalent t-butyl group (C(CH3)3) sites. The proton spin-lattice relaxation rates were measured between 90 and 310 K at NMR frequencies of 8.50, 22.5, and 53.0 MHz. The relaxometry data is fitted with two models characterizing the dynamics of the t-butyl groups and their constituent methyl groups, both of which are consistent with the determined x-ray structure. In addition to presenting results for TMP, we review previously reported x-ray diffractometry and low-frequency NMR relaxometry in two other van der Waals solids which have a simpler structure. In both cases, a unique model for the reorientational dynamics was found. Finally, we review a similar previously reported analysis in a van der Waals solid with a very complex structure in which case fitting the NMR relaxometry requires very many parameters and serves mainly as a flag for a careful x-ray diffraction study.

Experimental study of thermo-mechanical behavior of a thermosetting shape-memory polymer

NASA Astrophysics Data System (ADS)

Liu, Ruoxuan; Li, Yunxin; Liu, Zishun

2018-01-01

The thermo-mechanical behavior of shape-memory polymers (SMPs) serves for the engineering applications of SMPs. Therefore the understanding of thermo-mechanical behavior of SMPs is of great importance. This paper investigates the influence of loading rate and loading level on the thermo-mechanical behavior of a thermosetting shape-memory polymer through experimental study. A series of cyclic tension tests and shape recovery tests at different loading conditions are performed to study the strain level and strain rate effect. The results of tension tests show that the thermosetting shape-memory polymer will behave as rubber material at temperature lower than the glass transition temperature (Tg) and it can obtain a large shape fix ratio at cyclic loading condition. The shape recovery tests exhibit that loading rate and loading level have little effect on the beginning and ending of shape recovery process of the thermosetting shape-memory polymer. Compared with the material which is deformed at temperature higher than Tg, the material deformed at temperature lower than Tg behaves a bigger recovery speed.

Physical Modeling of Contact Processes on the Cutting Tools Surfaces of STM When Turning

NASA Astrophysics Data System (ADS)

Belozerov, V. A.; Uteshev, M. H.

2016-08-01

This article describes how to create an optimization model of the process of fine turning of superalloys and steel tools from STM on CNC machines, flexible manufacturing units (GPM), machining centers. Creation of the optimization model allows you to link (unite) contact processes simultaneously on the front and back surfaces of the tool from STM to manage contact processes and the dynamic strength of the cutting tool at the top of the STM. Established optimization model of management of the dynamic strength of the incisors of the STM in the process of fine turning is based on a previously developed thermomechanical (physical, heat) model, which allows the system thermomechanical approach to choosing brands STM (domestic and foreign) for cutting tools from STM designed for fine turning of heat resistant alloys and steels.

Tailored metal matrix composites for high-temperature performance

NASA Technical Reports Server (NTRS)

Morel, M. R.; Saravanos, D. A.; Chamis, C. C.

1992-01-01

A multi-objective tailoring methodology is presented to maximize stiffness and load carrying capacity of a metal matrix cross-ply laminated at elevated temperatures. The fabrication process and fiber volume ratio are used as the design variables. A unique feature is the concurrent effects from fabrication, residual stresses, material nonlinearity, and thermo-mechanical loading on the laminate properties at the post-fabrication phase. For a (0/90)(sub s) graphite/copper laminate, strong coupling was observed between the fabrication process, laminate characteristics, and thermo-mechanical loading. The multi-objective tailoring was found to be more effective than single objective tailoring. Results indicate the potential to increase laminate stiffness and load carrying capacity by controlling the critical parameters of the fabrication process and the laminate.

Evolution of grain boundary character distributions in alloy 825 tubes during high temperature annealing: Is grain boundary engineering achieved through recrystallization or grain growth?

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

Bai, Qin; Zhao, Qing

Grain boundary engineering (GBE) of nickel-based alloy 825 tubes was carried out with different cold drawing deformations by using a draw-bench on a factory production line and subsequent annealing at various temperatures. The microstructure evolution of alloy 825 during thermal-mechanical processing (TMP) was characterized by means of the electron backscatter diffraction (EBSD) technique to study the TMP effects on the grain boundary network and the evolution of grain boundary character distributions during high temperature annealing. The results showed that the proportion of ∑ 3{sup n} coincidence site lattice (CSL) boundaries of alloy 825 tubes could be increased to > 75%more » by the TMP of 5% cold drawing and subsequent annealing at 1050 °C for 10 min. The microstructures of the partially recrystallized samples and the fully recrystallized samples suggested that the proportion of low ∑ CSL grain boundaries depended on the annealing time. The frequency of low ∑ CSL grain boundaries increases rapidly with increasing annealing time associating with the formation of large-size highly-twinned grains-cluster microstructure during recrystallization. However, upon further increasing annealing time, the frequency of low ∑ CSL grain boundaries decreased markedly during grain growth. So it is concluded that grain boundary engineering is achieved through recrystallization rather than grain growth. - Highlights: •The grain boundary engineering (GBE) is applicable to 825 tubes. •GBE is achieved through recrystallization rather than grain growth. •The low ∑ CSL grain boundaries in 825 tubes can be increased to > 75%.« less

Long-term operation of submerged membrane bioreactor (MBR) for the treatment of synthetic wastewater containing styrene as volatile organic compound (VOC): Effect of hydraulic retention time (HRT).

PubMed

Fallah, N; Bonakdarpour, B; Nasernejad, B; Alavi Moghadam, M R

2010-06-15

In this study, the membrane bioreactor (MBR) was utilized to remove styrene from a synthetic wastewater having a chemical oxygen demand (COD) and styrene concentration of 1500 mg/L and 50 mg/L, respectively. At two hydraulic retention times (HRTs) of 24 h and 18 h, the MBR was operated for a period in excess of 100 days. The HRT effects were studied and it was found out that the removal efficiency of COD and styrene for both HRTs was consistently higher than 99%. Unlike conventional activated sludge processes (CASPs), no styrene was detected in the exhaust air, which meant that biodegradation was the major styrene removal mechanism at both HRTs. The transmembrane pressure (TMP) profile during the operation of the MBR showed a fairly low and constant TMP up to day 70, after which, the TMP showed a dramatic rise, as a result of the occurrence of severe membrane fouling. It was thought that an increase in styrene loading rate, when HRT was reduced to 18 h, resulted in the release of extracellular polymeric substance (EPS) from the bacterial cells, which in turn was responsible for the rise in soluble microbial product (SMP) and sludge deflocculation. The severe fouling observed during operation of MBR at HRT of 18 h was attributed to the rise in SMP concentrations and decrease in mean floc size and increase in the proportion of small particles in the activated sludge. Copyright 2010 Elsevier B.V. All rights reserved.

Selective phenol methylation to 2,6-dimethylphenol in a fluidized bed of iron-chromium mixed oxide catalyst with o-cresol circulation.

PubMed

Zukowski, Witold; Berkowicz, Gabriela; Baron, Jerzy; Kandefer, Stanisław; Jamanek, Dariusz; Szarlik, Stefan; Wielgosz, Zbigniew; Zielecka, Maria

2014-01-01

2,6-dimethylphenol (2,6-DMP) is a product of phenol methylation, especially important for the plastics industry. The process of phenol methylation in the gas phase is strongly exothermic. In order to ensure good temperature equalization in the catalyst bed, the process was carried out using a catalyst in the form of a fluidized bed - in particular, the commercial iron-chromium catalyst TZC-3/1. Synthesis of 2,6-dimethylphenol from phenol and methanol in fluidized bed of iron-chromium catalyst was carried out and the fluidization of the catalyst was examined. Stable state of fluidized bed of iron-chromium catalyst was achieved. The measured velocities allowed to determine the minimum flow of reactants, ensuring introduction of the catalyst bed in the reactor into the state of fluidization. Due to a high content of o-cresol in products of 2,6-dimethylphenol synthesis, circulation in the technological node was proposed. A series of syntheses with variable amount of o-cresol in the feedstock allowed to determine the parameters of stationary states. A stable work of technological node with o-cresol circulation is possible in the temperature range of350-380°C, and o-cresolin/phenolin molar ratio of more than 0.48. Synthesis of 2,6-DMP over the iron-chromium catalyst is characterized by more than 90% degree of phenol conversion. Moreover, the O-alkylation did not occur (which was confirmed by GC-MS analysis). By applying o-cresol circulation in the 2,6-DMP process, selectivity of more than 85% degree of 2,6-DMP was achieved. The participation levels of by-products: 2,4-DMP and 2,4,6-TMP were low. In the optimal conditions based on the highest yield of 2,6-DMP achieved in the technological node applying o-cresol circulation, there are 2%mol. of 2,4-DMP and 6%mol. of 2,4,6-TMP in the final mixture, whereas 2,4,6-TMP can be useful as a chain stopper and polymer's molar mass regulator during the polymerization of 2,6-DMP.

Effect of Thermomechanical Treatment on the Microstructure and Mechanical Properties of AISI 52100 Steel.

DTIC Science & Technology

1981-06-01

ofJue18 AISI 52100 Steel S. PERFOMING 04G. REOR "idMeRf 7. AUTHOR(e, A. CONTRACT ON GRANT NUmetta~s) Clarence W. Schultz S. P9m1FOMuNGw ORGMSIZATION...SUPPLEMENTARY NOTCS to. 14 IV WORDS (Cominu. -s bree coer It arneemp aE~ndt bay .4*l ONber) 52100 Steel , thermomechanical processing; heat treatment...AISI 52100 steel have been investigated using a canbination of optical and transmission electron microscopy in conjunction with standard mechanical

Inventory of File nam.t00z.hawaiinest.hiresf06.tm00.gr

Science.gov Websites

Water Equivalent [kg/m^2/s] 628 surface NCPCP 3-6 hour acc Large-Scale Precipitation (non-convective [non-dim] 010 1 hybrid level HGT 6 hour fcst Geopotential Height [gpm] 011 1 hybrid level TMP 6 hour [non-dim] 056 50 mb HGT 6 hour fcst Geopotential Height [gpm] 057 50 mb TMP 6 hour fcst Temperature [K

Inventory of File nam.t00z.firewxnest.hiresf06.tm00.gr

Science.gov Websites

Water Equivalent [kg/m^2/s] 628 surface NCPCP 5-6 hour acc Large-Scale Precipitation (non-convective [non-dim] 010 1 hybrid level HGT 6 hour fcst Geopotential Height [gpm] 011 1 hybrid level TMP 6 hour [non-dim] 056 50 mb HGT 6 hour fcst Geopotential Height [gpm] 057 50 mb TMP 6 hour fcst Temperature [K

Inventory of File nam.t00z.alaskanest.hiresf06.tm00.gr

Science.gov Websites

Water Equivalent [kg/m^2/s] 628 surface NCPCP 3-6 hour acc Large-Scale Precipitation (non-convective [non-dim] 010 1 hybrid level HGT 6 hour fcst Geopotential Height [gpm] 011 1 hybrid level TMP 6 hour [non-dim] 056 50 mb HGT 6 hour fcst Geopotential Height [gpm] 057 50 mb TMP 6 hour fcst Temperature [K

Inventory of File nam.t00z.conusnest.hiresf06.tm00.gri

Science.gov Websites

Water Equivalent [kg/m^2/s] 628 surface NCPCP 3-6 hour acc Large-Scale Precipitation (non-convective [non-dim] 010 1 hybrid level HGT 6 hour fcst Geopotential Height [gpm] 011 1 hybrid level TMP 6 hour [non-dim] 056 50 mb HGT 6 hour fcst Geopotential Height [gpm] 057 50 mb TMP 6 hour fcst Temperature [K

Inventory of File gfs.t06z.smartguam03.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 3 hour fcst Dew Point Temperature [K] 003 surface SPFH 3 hour fcst Specific surface 4LFTX 3 hour fcst Best (4 layer) Lifted Index [K] 019 surface TMP 2 hour fcst Temperature [K] 020 surface TMP 1 hour fcst Temperature [K] 021 surface DPT 2 hour fcst Dew Point Temperature [K] 022 surface

Inventory of File nam.t00z.smartak03.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 3 hour fcst Dew Point Temperature [K] 003 surface SPFH 3 hour fcst Specific fcst Haines Index [Numeric] 026 surface TMP 2 hour fcst Temperature [K] 027 surface TMP 1 hour fcst Temperature [K] 028 surface DPT 2 hour fcst Dew Point Temperature [K] 029 surface DPT 1 hour fcst Dew Point

Inventory of File gfs.t06z.smartguam18.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 18 hour fcst Dew Point Temperature [K] 003 surface SPFH 18 hour fcst Specific TMP 17 hour fcst Temperature [K] 022 surface TMP 16 hour fcst Temperature [K] 023 surface DPT 17 hour fcst Dew Point Temperature [K] 024 surface DPT 16 hour fcst Dew Point Temperature [K] 025 surface TMAX

Inventory of File spread.sref.cluster1.f03.grib2

Science.gov Websites

Records: 40 Number Level/Layer Parameter Forecast Valid Description 001 2 m above ground TMP 3 hour fcst Temperature [K] std dev 002 2 m above ground TMP 3 hour fcst Temperature [K] std dev 003 2 m above ground SPFH 3 hour fcst Specific Humidity [kg/kg] std dev 004 2 m above ground RH 3 hour fcst Relative Humidity

Inventory of File mean.sref.cluster1.f03.grib2

Science.gov Websites

Records: 40 Number Level/Layer Parameter Forecast Valid Description 001 2 m above ground TMP 3 hour fcst Temperature [K] wt ens-mean 002 2 m above ground TMP 3 hour fcst Temperature [K] wt ens-mean 003 2 m above ground SPFH 3 hour fcst Specific Humidity [kg/kg] wt ens-mean 004 2 m above ground RH 3 hour fcst

Communication: Glass transition and melting lines of an ionic liquid

NASA Astrophysics Data System (ADS)

Lima, Thamires A.; Faria, Luiz F. O.; Paschoal, Vitor H.; Ribeiro, Mauro C. C.

2018-05-01

The phase diagram of the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesufonyl)imide, [Pyrr1,4][NTf2], was explored by synchroton X-ray diffraction and Raman scattering measurements as a function of temperature and pressure. Glass transition Tg(p) and melting Tm(p) temperatures were obtained from atmospheric pressure up to ca. 2.0 GPa. We found that both the Tg(p) and Tm(p) curves follow essentially the same pressure dependence. The similarity of pressure coefficients, dTg/dp ≈ dTm/dp, is explained within the non-equilibrium thermodynamics approach for the glass transition by assuming that one of the Ehrenfest equations is appropriated for Tg(p), whereas Tm(p) follows the Clausius-Clapeyron equation valid for the first-order transitions. The results highlight that ionic liquids are excellent model systems to address fundamental questions related to the glass transition.

Fabrication and Characterization of SMA Hybrid Composites

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Lach, Cynthia L.; Cano, Robert J.

2001-01-01

Results from an effort to fabrication shape memory alloy hybrid composite (SMAHC) test specimens and characterize the material system are presented in this study. The SMAHC specimens are conventional composite structures with an embedded SMA constituent. The fabrication and characterization work was undertaken to better understand the mechanics of the material system, address fabrication issues cited in the literature, and provide specimens for experimental validation of a recently developed thermomechanical model for SMAHC structures. Processes and hardware developed for fabrication of the SMAHC specimens are described. Fabrication of a SMA14C laminate with quasi-isotropic lamination and ribbon-type Nitinol actuators embedded in the 0' layers is presented. Beam specimens are machined from the laminate and are the focus of recent work, but the processes and hardware are readily extensible to more practical structures. Results of thermomechanical property testing on the composite matrix and Nitinol ribbon are presented. Test results from the Nitinol include stress-strain behavior, modulus versus temperature. and constrained recovery stress versus temperature and thermal cycle. Complex thermomechanical behaviors of the Nitinol and composite matrix are demonstrated, which have significant implications for modeling of SMAHC structures.

Effect of Thermomechanical Treatment on the Environmentally Induced Cracking Behavior of AA7075 Alloy

NASA Astrophysics Data System (ADS)

Ghosh, Rahul; Venugopal, A.; Sankaravelayudham, P.; Panda, Rajiv; Sharma, S. C.; George, Koshy M.; Raja, V. S.

2015-02-01

The influence of thermomechanical treatment on the stress corrosion cracking behavior of AA7075 aluminum alloy forgings was examined in 3.5% NaCl solution by varying the extent of thermomechanical working imparted to each of the conditions. The results show that inadequate working during billet processing resulted in inferior corrosion and mechanical properties. However, more working with intermediate pre-heating stages also led to precipitation of coarse particles resulting in lowering of mechanical properties marginally and a significant reduction in the general/pitting corrosion resistance. The results obtained in the present study indicate that optimum working with controlled pre-heating levels is needed during forging to achieve the desired properties. It is also demonstrated that AA7075 in the over aged condition does not show any environmental cracking susceptibility in spite of the microstructural variations in terms of size and volume fraction of the precipitates. However, the above microstructural variations definitely affected the pitting corrosion and mechanical properties significantly and hence a strict control over the working and pre-heating stages during billet processing is suggested.

Thermo-mechanical modeling of laser treatment on titanium cold-spray coatings

NASA Astrophysics Data System (ADS)

Paradiso, V.; Rubino, F.; Tucci, F.; Astarita, A.; Carlone, P.

2018-05-01

Titanium coatings are very attractive to several industrial fields, especially aeronautics, due to the enhanced corrosion resistance and wear properties as well as improved compatibility with carbon fiber reinforced plastic (CFRP) materials. Cold sprayed titanium coatings, among the others deposition processes, are finding a widespread use in high performance applications, whereas post-deposition treatments are often used to modify the microstructure of the cold-sprayed layer. Laser treatments allow one to noticeably increase the superficial properties of titanium coatings when the process parameters are properly set. On the other hand, the high heat input required to melt titanium particles may result in excessive temperature increase even in the substrate. This paper introduces a thermo-mechanical model to simulate the laser treatment effects on a cold sprayed titanium coating as well as the aluminium substrate. The proposed thermo-mechanical finite element model considers the transient temperature field due to the laser source and applied boundary conditions using them as input loads for the subsequent stress-strain analysis. Numerical outcomes highlighted the relevance of thermal gradients and thermally induced stresses and strains in promoting the damage of the coating.

Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

NASA Astrophysics Data System (ADS)

Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

2016-04-01

The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

Thermomechanical Response of Self-Assembled Nanoparticle Membranes

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

Wang, Yifan; Chan, Henry; Narayanan, Badri

2017-07-21

Monolayers composed of colloidal nanoparticles, with a thickness of less than 10 nm, have remarkable mechanical moduli and can suspend over micrometer-sized holes to form free-standing membranes. In this paper, we discuss experiment's and coarse-grained molecular dynamics simulations characterizing the thermomechanical properties of these self-assembled nanoparticle membranes. These membranes remain strong and resilient up to temperatures much higher than previous simulation predictions and exhibit an unexpected hysteretic behavior during the first heating cooling cycle. We show this hysteretic behavior can be explained by an asymmetric ligand configuration from the self assembly process and can be controlled by changing the ligandmore » coverage or cross-linking the ligand molecules. Finally, we show the screening effect of water molecules on the ligand interactions can strongly affect the moduli and thermomechanical behavior.« less

Thermo-mechanical behavior of power electronic packaging assemblies: From characterization to predictive simulation of lifetimes

NASA Astrophysics Data System (ADS)

Dalverny, O.; Alexis, J.

2018-02-01

This article deals with thermo-mechanical behavior of power electronic modules used in several transportation applications as railway, aeronautic or automotive systems. Due to a multi-layered structures, involving different materials with a large variation of coefficient of thermal expansion, temperature variations originated from active or passive cycling (respectively from die dissipation or environmental constraint) induces strain and stresses field variations, giving fatigue phenomenon of the system. The analysis of the behavior of these systems and their dimensioning require the implementation of complex modeling strategies by both the multi-physical and the multi-scale character of the power modules. In this paper we present some solutions for studying the thermomechanical behavior of brazed assemblies as well as taking into account the interfaces represented by the numerous metallizations involved in the process assembly.

Thermo-Mechanical Analysis for John Deere Electronics Solutions | Advanced

Science.gov Websites

impacts of alternative manufacturing processes Die, package, and interface material analysis for power module reliability Manufacturing process impacts versus thermal cycling impacts on power module

Development of Ti microalloyed high strength steel plate by controlling thermo-mechanical control process schedule

NASA Astrophysics Data System (ADS)

Xia, Jinian; Huo, Xiangdong; Li, Liejun; Peng, Zhengwu; Chen, Songjun

2017-12-01

In this study, the TMCP parameters including non-recrystallization temperature (Tnr) and optimal isothermal temperature were determined by thermal simulation experiments, and a new Ti microalloyed high strength steel plate was developed by controlling thermo-mechanical control process (TMCP) schedule. The effects of TMCP process on microstructural features, precipitation behavior and mechanical properties of Ti microalloyed high strength steel plate were investigated. The results revealed that the double-stage rolling process consist of rolling in the γ recrystallization region and the γ non-recrystallization region was benefical to promoting the mechanical properties of Ti microalloyed steel by achieving grain refinement. It was also found that large amounts of fine TiC (<10 nm) particles were precipitated during the isothermal treatment at 600 °C, which generated a 215 MPa precipitation strengthening effect.

Thermomechanical simulations and experimental validation for high speed incremental forming

NASA Astrophysics Data System (ADS)

Ambrogio, Giuseppina; Gagliardi, Francesco; Filice, Luigino; Romero, Natalia

2016-10-01

Incremental sheet forming (ISF) consists in deforming only a small region of the workspace through a punch driven by a NC machine. The drawback of this process is its slowness. In this study, a high speed variant has been investigated from both numerical and experimental points of view. The aim has been the design of a FEM model able to perform the material behavior during the high speed process by defining a thermomechanical model. An experimental campaign has been performed by a CNC lathe with high speed to test process feasibility. The first results have shown how the material presents the same performance than in conventional speed ISF and, in some cases, better material behavior due to the temperature increment. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process confirming substantially experimental evidence.

Evaluating cis-2,6-Dimethylpiperidide (cis-DMP) as a Base Component in Lithium-Mediated Zincation Chemistry

PubMed Central

Armstrong, David R; Garden, Jennifer A; Kennedy, Alan R; Leenhouts, Sarah M; Mulvey, Robert E; O'Keefe, Philip; O'Hara, Charles T; Steven, Alan

2013-01-01

Most recent advances in metallation chemistry have centred on the bulky secondary amide 2,2,6,6-tetramethylpiperidide (TMP) within mixed metal, often ate, compositions. However, the precursor amine TMP(H) is rather expensive so a cheaper substitute would be welcome. Thus this study was aimed towards developing cheaper non-TMP based mixed-metal bases and, as cis-2,6-dimethylpiperidide (cis-DMP) was chosen as the alternative amide, developing cis-DMP zincate chemistry which has received meagre attention compared to that of its methyl-rich counterpart TMP. A new lithium diethylzincate, [(TMEDA)LiZn(cis-DMP)Et2] (TMEDA=N,N,N′,N′-tetramethylethylenediamine) has been synthesised by co-complexation of Li(cis-DMP), Et2Zn and TMEDA, and characterised by NMR (including DOSY) spectroscopy and X-ray crystallography, which revealed a dinuclear contact ion pair arrangement. By using N,N-diisopropylbenzamide as a test aromatic substrate, the deprotonative reactivity of [(TMEDA)LiZn(cis-DMP)Et2] has been probed and contrasted with that of the known but previously uninvestigated di-tert-butylzincate, [(TMEDA)LiZn(cis-DMP)tBu2]. The former was found to be the superior base (for example, producing the ortho-deuteriated product in respective yields of 78 % and 48 % following D2O quenching of zincated benzamide intermediates). An 88 % yield of 2-iodo-N,N-diisopropylbenzamide was obtained on reaction of two equivalents of the diethylzincate with the benzamide followed by iodination. Comparisons are also drawn using 1,1,1,3,3,3-hexamethyldisilazide (HMDS), diisopropylamide and TMP as the amide component in the lithium amide, Et2Zn and TMEDA system. Under certain conditions, the cis-DMP base system was found to give improved results in comparison to HMDS and diisopropylamide (DA), and comparable results to a TMP system. Two novel complexes isolated from reactions of the di-tert-butylzincate and crystallographically characterised, namely the pre-metallation complex [{(iPr)2N(Ph)C=O}LiZn(cis-DMP)tBu2] and the post-metallation complex [(TMEDA)Li(cis-DMP){2-[1-C(=O)N(iPr)2]C6H4}Zn(tBu)], shed valuable light on the structures and mechanisms involved in these alkali-metal-mediated zincation reactions. Aspects of these reactions are also modelled by DFT calculations. PMID:23955639

Prediction of drinking water intake by dairy cows.

PubMed

Appuhamy, J A D R N; Judy, J V; Kebreab, E; Kononoff, P J

2016-09-01

Mathematical models that predict water intake by drinking, also known as free water intake (FWI), are useful in understanding water supply needed by animals on dairy farms. The majority of extant mathematical models for predicting FWI of dairy cows have been developed with data sets representing similar experimental conditions, not evaluated with modern cows, and often require dry matter intake (DMI) data, which may not be routinely available. The objectives of the study were to (1) develop a set of new empirical models for predicting FWI of lactating and dry cows with and without DMI using literature data, and (2) evaluate the new and the extant models using an independent set of FWI measurements made on modern cows. Random effect meta-regression analyses were conducted using 72 and 188 FWI treatment means with and without dietary electrolyte and daily mean ambient temperature (TMP) records, respectively, for lactating cows, and 19 FWI treatment means for dry cows. Milk yield, DMI, body weight, days in milk, dietary macro-nutrient contents, an aggregate milliequivalent concentration of dietary sodium and potassium (NaK), and TMP were used as potential covariates to the models. A model having positive relationships of DMI, dietary dry matter (DM%), and CP (CP%) contents, NaK, and TMP explained 76% of variability in FWI treatment means of lactating cows. When challenged on an independent data set (n=261), the model more accurately predicted FWI [root mean square prediction error as a percentage of average observed value (RMSPE%)=14.4%] compared with a model developed without NaK and TMP (RMSPE%=17.3%), and all extant models (RMSPE%≥15.7%). A model without DMI included positive relationships of milk yield, DM%, NaK, TMP, and days in milk, and explained 63% of variability in the FWI treatment means and performed well (RMSPE%=17.9%), when challenged on the independent data. New models for dry cows included positive relationships of DM% and TMP along with DMI or body weight. The new models with and without DMI explained 75 and 54% of the variability in FWI treatment means of dry cows and had RMSPE% of 12.8 and 15.2%, respectively, when evaluated with the literature data. The study offers a set of empirical models that can assist in determining drinking water needs of dairy farms. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The Effects of Ligustrazine on the Ca2+ Concentration of Soleus and Gastrocnemius Muscle Fibers in Hindlimb Unloaded Rat

NASA Astrophysics Data System (ADS)

Gao, Yunfang; Goswami, Nandu; Du, Bei; Hu, Huanxin; Wu, Xue

Background Spaceflight or inactivity (bed rest, limb immobilization, hindlimb unloading) causes skeletal muscle atrophy. Recent studies show that an increase in protein degradation is an important mechanism for disuse atrophy. Furthermore, the calcium overload of disuse-atrophied muscle fiber has been shown to initiate the skeletal muscle proteolysis in disuse atrophy. Ligustrazine (tetramethylpyrazine, TMP), one of the important active ingredient extracted from Chuanxiong, has been shown by our group to increase muscle fiber cross-sectional area in atrophied soleus induced by 14 days hindlimb unloading. However, the underlying mechanisms of ligustrazine effects on disuse-atrophied muscle fibers remain unknown. Objective: We investigated the effects of ligustrazine on the cytoplasmic calcium overloading in soleus and gastrocnemius in 14 days hindlimb unloaded (HU) rats. Methods: Adult female Sprague-Dawley rats were matched for body mass and randomly assigned to three groups (n=8, each group): 1) synchronous control (CON); HU + intragastric water instillation (HU+W); HU + intragastric 60.0 mg kg-1 ligustrazine instillation (HU+Tmp). Laser scanning confocal microscope assessed the concentrations of cytoplasmic calcium ions. Spaceflight disuse atrophy was simulated by hindlimb unloading, provided by tail suspension. Results: 1) Compared with CON, the concentration of soleus intracellular calcium ion in HU+W and HU+Tmp increased 330% and 86% respectively P<0.01). Compared with HU+W, the concentration of soleus intracellular calcium ion in HU+Tmp decreased by 130% P<0.01). 2) Compared with CON, the concentration of gastrocnemius intracellular calcium ion in HU+W and HU+Tmp increased 189.8% and 32.1% respectively P<0.01). Compared with HU+W, the concentration of gastrocnemius intracellular calcium ion in HU+Tmp decreased by 119.3% (P<0.01). Conclusion: After 14 days of hindlimb unloading, cytoplasmic calcium of soleus (slow-twitch muscle) and gastrocnemius (fast-twitch muscle) showed significant overload. This was especially true for the soleus. Ligustrazine appears to inhibit the cytoplasmic calcium overload thus leadig to lesser muscle atrophy in hindlimb unloaded animals. Therefore, ligustrazine may play important role in preventing muscle loss during spaceflight. Key words: Ligustrazine; Tetramethylpyrazine; disuse atrophy; calcium overload; soleus; gastrocnemius; spaceflight This work was supported by funds from the National Natural Science Foundation of China (Grant No. 31270455), International Scientific and Technological Cooperation Projects in Shaanxi Province of China (Grant No. 2013KW26-01).

New Nomenclatures for Heat Treatments of Additively Manufactured Titanium Alloys

NASA Astrophysics Data System (ADS)

Baker, Andrew H.; Collins, Peter C.; Williams, James C.

2017-07-01

The heat-treatment designations and microstructure nomenclatures for many structural metallic alloys were established for traditional metals processing, such as casting, hot rolling or forging. These terms do not necessarily apply for additively manufactured (i.e., three-dimensionally printed or "3D printed") metallic structures. The heat-treatment terminology for titanium alloys generally implies the heat-treatment temperatures and their sequence relative to a thermomechanical processing step (e.g., forging, rolling). These designations include: β-processing, α + β-processing, β-annealing, duplex annealing and mill annealing. Owing to the absence of a thermomechanical processing step, these traditional designations can pose a problem when titanium alloys are first produced via additive manufacturing, and then heat-treated. This communication proposes new nomenclatures for heat treatments of additively manufactured titanium alloys, and uses the distinct microstructural features to provide a correlation between traditional nomenclature and the proposed nomenclature.

Effects of Thermomechanical History on the Tensile Behavior of Nitinol Ribbon

NASA Technical Reports Server (NTRS)

Lach, Cynthia L.; Turner, Travis L.; Taminger, Karen M.; Shenoy, Ravi N.

2002-01-01

Shape memory alloys (SMAs) have enormous potential for a wide variety of applications. A large body of work exists on the characterization of the microstructure and stress-strain behavior of these alloys, Nitinol (NiTi) in particular. However, many attributes of these materials are yet to be fully understood. Previous work at NASA Langley Research Center (LaRC) has included fabrication of hybrid composite specimens with embedded Nitinol actuators and modeling of their thermomechanical behavior. An intensive characterization effort has been undertaken to facilitate fundamental understanding of this alloy and to promote implementation of Nitinol in aerospace applications. Previous work revealed attributes of the Nitinol ribbon that were not easily rationalized with existing data in the literature. In particular, tensile behavior at ambient temperature showed significant dependence on the thermomechanical history prior to testing. The present work is focused on characterizing differences in the microstructure of Nitinol ribbons exposed to four different thermomechanical histories and correlation of the microstructure with tensile properties. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) analysis were employed to rationalize the microstructures present after exposure to various thermomechanical histories. Three of the Nitinol ribbon conditions were reversible upon heating (in the DSC) through the reverse transformation temperature (A(sub f) to transform the microstructure to austenite. However, the prior thermomechanical conditioning for the Nitinol ribbon that reflected the entire fabrication procedure (4% thermal cycle condition) was found to have an irreversible effect on the microstructure, as it remained unchanged after repeated complete thermal cycles. Tensile tests were conducted to determine the effect of prior thermomechancal conditioning on both the tensile behavior of the Nitinol ribbons and the stress state of the microstructure. The stress-strain behavior of the Nitinol actuators appears to be governed by the interplay between two major variables: namely, microstructural constituents such as the R-phase and the martensite; and the stress state of these constituents (whether twinned with low residual stresses, or detwinned with high residual stresses). The most significant difference in the stress-strain behavior of the four conditions, the critical stress required to achieve an initial stress plateau, was found to depend on both the amount and stress state (twinned or detwinned) of R-phase present in the initial microstructure. Thus, the effect of prior thermomechanical processing is critical to the resulting tensile behavior of the Nitinol actuator. For numerical modeling inputs one must take into account the entire fabrication process on the Nitinol actuator.

Inventory of File SN.2012091412.grib6th.f18.grib2

Science.gov Websites

ground UGRD 18 hour fcst U-Component of Wind [m/s] 003.2 35 m above ground VGRD 18 hour fcst V-Component of Wind [m/s] 004 surface TMP 18 hour fcst Temperature [K] 005 0.5 m underground TMP 18 hour fcst ] 008.1 10 mb UGRD 18 hour fcst U-Component of Wind [m/s] 008.2 10 mb VGRD 18 hour fcst V-Component of

Cardiac toxoplasmosis after heart transplantation diagnosed by endomyocardial biopsy.

PubMed

Petty, L A; Qamar, S; Ananthanarayanan, V; Husain, A N; Murks, C; Potter, L; Kim, G; Pursell, K; Fedson, S

2015-10-01

We describe a case of cardiac toxoplasmosis diagnosed by routine endomyocardial biopsy in a patient with trimethoprim-sulfamethoxazole (TMP-SMX) intolerance on atovaquone prophylaxis. Data are not available on the efficacy of atovaquone as Toxoplasma gondii prophylaxis after heart transplantation. In heart transplant patients in whom TMP-SMX is not an option, other strategies may be considered, including the addition of pyrimethamine to atovaquone. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Substrate-Dependence of Competitive Nucleotide Pyrophosphatase/Phosphodiesterase1 (NPP1) Inhibitors

PubMed Central

Lee, Sang-Yong; Sarkar, Soumya; Bhattarai, Sanjay; Namasivayam, Vigneshwaran; De Jonghe, Steven; Stephan, Holger; Herdewijn, Piet; El-Tayeb, Ali; Müller, Christa E.

2017-01-01

Nucleotide pyrophosphatase/phosphodiesterase type 1 (NPP1) is a membrane glycoprotein involved in the hydrolysis of extracellular nucleotides. Its major substrate is ATP which is converted to AMP and diphosphate. NPP1 was proposed as a new therapeutic target in brain cancer and immuno-oncology. Several NPP1 inhibitors have been reported to date, most of which were evaluated vs. the artificial substrate p-nitrophenyl 5′-thymidine monophosphate (p-Nph-5′-TMP). Recently, we observed large discrepancies in inhibitory potencies for a class of competitive NPP1 inhibitors when tested vs. the artificial substrate p-Nph-5′-TMP as compared to the natural substrate ATP. Therefore, the goal of the present study was to investigate whether inhibitors of human NPP1 generally display substrate-dependent inhibitory potency. Systematic evaluation of nucleotidic as well as non-nucleotidic NPP1 inhibitors revealed significant differences in determined Ki values for competitive, but not for non- and un-competitive inhibitors when tested vs. the frequently used artificial substrate p-Nph-5′-TMP as compared to ATP. Allosteric modulation of NPP1 by p-Nph-5′-TMP may explain these discrepancies. Results obtained using the AMP derivative p-nitrophenyl 5′-adenosine monophosphate (p-Nph-5′-AMP) as an alternative artificial substrate correlated much better with those employing the natural substrate ATP. PMID:28261095

A Review on the Synthesis and Applications of Mesostructured Transition Metal Phosphates

PubMed Central

Lin, Ronghe; Ding, Yunjie

2013-01-01

Considerable efforts have been devoted to extending the range of the elemental composition of mesoporous materials since the pioneering work of the M41S family of ordered mesoporous silica by Mobil researchers. The synthesis of transition metal-containing mesostructured materials with large surface area and high porosity has drawn great attention for its potential applications in acid and redox catalysis, photocatalysis, proton conducting devices, environmental restoration and so on. Thus, various transition metals-containing mesoporous materials, including transition metal-substituted mesoporous silicates, mesostructured transition metal oxides and transition metal phosphates (TMP), have been documented in the literature. Among these, mesostructured TMP materials are less studied, but possess some unique features, partly because of the easy and facile functionalization of PO4 and/or P–OH groups, rendering them interesting functional materials. This review first introduced the general synthesis strategies for manufacturing mesostructured TMP materials, as well as advantages and disadvantages of the respective method; then, we surveyed the ongoing developments of fabrication and application of the TMP materials in three groups on the basis of their components and application fields. Future perspectives on existing problems related to the present synthesis routes and further modifying of the functional groups for the purpose of tailoring special physical-chemical properties to meet wide application requirements were also provided in the last part. PMID:28809304

Green method by diffuse reflectance infrared spectroscopy and spectral region selection for the quantification of sulphamethoxazole and trimethoprim in pharmaceutical formulations.

PubMed

da Silva, Fabiana E B; Flores, Érico M M; Parisotto, Graciele; Müller, Edson I; Ferrão, Marco F

2016-03-01

An alternative method for the quantification of sulphametoxazole (SMZ) and trimethoprim (TMP) using diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and partial least square regression (PLS) was developed. Interval Partial Least Square (iPLS) and Synergy Partial Least Square (siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Fifteen commercial tablet formulations and forty-nine synthetic samples were used. The ranges of concentration considered were 400 to 900 mg g-1SMZ and 80 to 240 mg g-1 TMP. Spectral data were recorded between 600 and 4000 cm-1 with a 4 cm-1 resolution by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The proposed procedure was compared to high performance liquid chromatography (HPLC). The results obtained from the root mean square error of prediction (RMSEP), during the validation of the models for samples of sulphamethoxazole (SMZ) and trimethoprim (TMP) using siPLS, demonstrate that this approach is a valid technique for use in quantitative analysis of pharmaceutical formulations. The selected interval algorithm allowed building regression models with minor errors when compared to the full spectrum PLS model. A RMSEP of 13.03 mg g-1for SMZ and 4.88 mg g-1 for TMP was obtained after the selection the best spectral regions by siPLS.

Collaborative Research and Development Contract. Delivery Order 0047: Mesocscale Modeling of the Thermal Mechanical Processing (TMP) of Superalloys

DTIC Science & Technology

2008-08-01

zones is already accounted for in Eq. [42]): Se total ¼ XNMSU k¼1 Sek Sb total ¼ Stotal Sb total ½45 Knowing these two total-boundary densities...MSUs (i > Nbt), the assumption is made that each of them contributes to Sb total proportionally to its own surface: Sebc total ¼ XNMSU k¼N bt þ1 Sek

Treatment of oil sands process-affected water (OSPW) using a membrane bioreactor with a submerged flat-sheet ceramic microfiltration membrane.

PubMed

Xue, Jinkai; Zhang, Yanyan; Liu, Yang; Gamal El-Din, Mohamed

2016-01-01

The release of oil sands process-affected water (OSPW) into the environment is a concern because it contains persistent organic pollutants that are toxic to aquatic life. A modified Ludzack-Ettinger membrane bioreactor (MLE-MBR) with a submerged ceramic membrane was continuously operated for 425 days to evaluate its feasibility on OSPW treatment. A stabilized biomass concentration of 3730 mg mixed liquor volatile suspended solids per litre and a naphthenic acid (NA) removal of 24.7% were observed in the reactor after 361 days of operation. Ultra Performance Liquid Chromatography/High Resolution Mass Spectrometry analysis revealed that the removal of individual NA species declined with increased ring numbers. Pyrosequencing analysis revealed that Betaproteobacteria were dominant in sludge samples from the MLE-MBR, with microorganisms such as Rhodocyclales and Sphingobacteriales capable of degrading hydrocarbon and aromatic compounds. During 425 days of continuous operation, no severe membrane fouling was observed as the transmembrane pressure (TMP) of the MLE-MBR never exceeded -20 kPa given that the manufacturer's suggested critical TMP for chemical cleaning is -35 kPa. Our results indicated that the proposed MLE-MBR has a good potential for removing recalcitrant organics in OSPW. Copyright © 2015 Elsevier Ltd. All rights reserved.

Straightforward Downsizing of Inclusions in NiTi Alloys: A New Generation of SMA Wires with Outstanding Fatigue Life

NASA Astrophysics Data System (ADS)

Coda, Alberto; Cadelli, Andrea; Zanella, Matteo; Fumagalli, Luca

2018-03-01

One of most debated aspects around Nitinol quality is microcleanliness, nowadays considered as the main factor affecting fatigue life. Recent results demonstrate that fatigue is undoubtedly associated with inclusions which can act as crack initiators. However, type, size, and distribution of such particles have been observed to strongly depend on Ni/Ti ratio as well as melting and thermo-mechanical processes. Therefore, if a general reduction of non-metallic inclusions is expected to generate a beneficial effect in improving lifetime of Nitinol, on the other hand this necessarily involves a hard review of both material melting and processing. In this work, the characterization of the fatigue behavior of SMA wires with diameter below 100 µm is presented. The wires were prepared by a peculiar, non-standard combination of melting and thermo-mechanical processes (Clean Melt technology). Thermo-mechanical cycling was carried out and the fracture surfaces of all failed wires were investigated by scanning electron microscopy. A robust set of data was collected and analyzed by using the statistics of extremes. Results clearly demonstrate that in the new NiTi Clean Melt alloy the maximum inclusion size and area fraction are significantly reduced compared to standard Nitinol. This offers meaningful improvement in fatigue resistance over standard wires.

Effects of thermomechanical processing on tensile and long-time creep behavior of Nb-1 percent Zr-0.1 percent C sheet

NASA Technical Reports Server (NTRS)

Titran, Robert H.; Uz, Mehmet

1994-01-01

Effects of thermomechanical processing on the mechanical properties of Nb-1 wt. percent Zr-0.1 wt. percent C, a candidate alloy for use in advanced space power systems, were investigated. Sheet bars were cold rolled into 1-mm thick sheets following single, double, or triple extrusion operations at 1900 K. All the creep and tensile specimens were given a two-step heat treatment 1 hr at 1755 K + 2 hr 1475 K prior to testing. Tensile properties were determined at 300 as well as at 1350 K. Microhardness measurements were made on cold rolled, heat treated, and crept samples. Creep tests were carried out at 1350 K and 34.5 MPa for times of about 10,000 to 19,000 hr. The results show that the number of extrusions had some effects on both the microhardness and tensile properties. However, the long-time creep behavior of the samples were comparable, and all were found to have adequate properties to meet the design requirements of advanced power systems regardless of thermomechanical history. The results are discussed in correlation with processing and microstructure, and further compared to the results obtained from the testing of Nb-1 wt. percent Zr and Nb-1 wt. percent Zr-0.06 wt. percent C alloys.

The aquatic fate of triclopyr in whole-pond treatments

USGS Publications Warehouse

Petty, D.G.; Skogerboe, J.G.; Getsinger, K.D.; Foster, D.R.; Houtman, B.A.; Fairchild, J.F.; Anderson, L.W.

2001-01-01

The aquatic fate of the triethylamine salt formulation of triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) was determined in whole-pond applications in closed (no water exchange) systems in California, Missouri and Texas in two studies conducted in 1995 and 1996. These studies determined dissipation rates of triclopyr and its principal metabolites, 3,5,6-trichloropyridinol (tcp) and 3,5,6-trichloro-2-methoxypyridine (tmp) in water, sediment and finfish. Ponds at each site containing a healthy biological community were treated at 2.5 mg AE litre-1 triclopyr. Water and sediment samples were collected through 12 weeks post-treatment, and non-target animals were collected through 4 weeks post-treatment. Dissipation rates for triclopyr, TCP and TMP were similar at each of the study sites, despite differences in weather, water quality, biotic community, light transmission and geographic location. Half-lives of triclopyr in water ranged from 5.9 to 7.5 days, while those of TCP and TMP ranged from 4 to 8.8 and 4 to 10 days, respectively. Levels of triclopyr and TCP declined in sediments at half-lives ranging from 2.8 to 4.6 days and 3.8 to 13.3 days, respectively. No TMP was detected in sediment. Triclopyr and TCP cleared from fish in relation to concentrations found in the water column. TMP levels in fish were generally an order of magnitude higher than levels of triclopyr and TCP, particularly in the visceral portion of the animals. No adverse effects on water quality or on the non-target biotic community were found following triclopyr applications. Results of these studies were comparable to those of triclopyr dissipation studies conducted in reservoirs, lakes and riverine systems in Georgia, Florida, Minnesota and Washington, indicating that the degradation and dissipation of triclopyr and its metabolites are similar in representative systems throughout the USA. ?? 2001 Society of Chemical Industry.

Development and validation of a normal-phase high-performance thin layer chromatographic method for the analysis of sulfamethoxazole and trimethoprim in co-trimoxazole tablets.

PubMed

Shewiyo, D H; Kaale, E; Risha, P G; Dejaegher, B; Smeyers-Verbeke, J; Vander Heyden, Y

2009-10-16

Pneumocystis carinii pneumonia (PCP) is often the ultimate mortal cause for immunocompromised individuals, such as HIV/AIDS patients. Currently, the most effective medicine for treatment and prophylaxis is co-trimoxazole, a synergistic combination of sulfamethoxazole (SMX) and trimethoprim (TMP). In order to ensure a continued availability of high quality co-trimoxazole tablets within resource-limited countries, Medicines Regulatory Authorities must perform quality control of these products. However, most pharmacopoeial methods are based on high-performance liquid chromatographic (HPLC) methods. Because of the lack of equipment, the Tanzania Food and Drugs Authority (TFDA) laboratory decided to develop and validate an alternative method of analysis based on the TLC technique with densitometric detection, for the routine quality control of co-trimoxazole tablets. SMX and TMP were separated on glass-backed silica gel 60 F(254) plates in a high-performance thin layer chromatograph (HPTLC). The mobile phase was comprised of toluene, ethylacetate and methanol (50:28.5:21.5, v:v:v). Detection wavelength was 254 nm. The R(f) values were 0.30 and 0.61 for TMP and SMX, respectively. This method was validated for linearity, precision, trueness, specificity and robustness. Cochran's criterion test indicated homoscedasticity of variances for the calibration data. The F-tests for lack-of-fit indicated that straight lines were adequate to describe the relationship between spot areas and concentrations for each compound. The percentage relative standard deviations for repeatability and time-different precisions were 0.98 and 1.32, and 0.83 and 1.64 for SMX and TMP, respectively. Percentage recovery values were 99.00%+/-1.83 and 99.66%+/-1.21 for SMX and TMP, respectively. The method was found to be robust and was then successfully applied to analyze co-trimoxazole tablet samples.

The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance.

PubMed

Derlon, Nicolas; Grütter, Alexander; Brandenberger, Fabienne; Sutter, Anja; Kuhlicke, Ute; Neu, Thomas R; Morgenroth, Eberhard

2016-10-01

This study aimed at identifying how to improve the level of permeate flux stabilisation during gravity-driven membrane filtration without control of biofilm formation. The focus was therefore on understanding (i) how the different fractions of the biofilms (inorganics particles, bacterial cells, EPS matrix) influence its hydraulic resistance and (ii) how the compression of biofilms impacts its hydraulic resistance, i.e., can water head be increased to increase the level of permeate flux stabilisation. Biofilms were developed on ultrafiltration membranes at 88 and 284 cm water heads with dead-end filtration for around 50 days. A larger water head resulted in a smaller biofilm permeability (150 and 50 L m(-2) h(-1) bar(-1) for biofilms grown at 88 cm and 284 cm water head, respectively). Biofilms were mainly composed of EPS (>90% in volume). The comparison of the hydraulic resistances of biofilms to model fouling layers indicated that most of the hydraulic resistance is due to the EPS matrix. The compressibility of the biofilm was also evaluated by subjecting the biofilms to short-term (few minutes) and long-term variations of transmembrane pressures (TMP). A sudden change of TMP resulted in an instantaneous and reversible change of biofilm hydraulic resistance. A long-term change of TMP induced a slow change in the biofilm hydraulic resistance. Our results demonstrate that the response of biofilms to a TMP change has two components: an immediate variation of resistance (due to compression/relaxation) and a long-term response (linked to biofilm adaptation/growth). Our results provide relevant information about the relationship between the operating conditions in terms of TMP, the biofilm structure and composition and the resulting biofilm hydraulic resistance. These findings have practical implications for a broad range of membrane systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of pulsed UV-irradiation and pre-coagulation to control ultrafiltration membrane fouling in the treatment of micro-polluted surface water.

PubMed

Yu, Wenzheng; Campos, Luiza C; Graham, Nigel

2016-12-15

A major cause of ultrafiltration (UF) membrane fouling is the accumulation of microorganisms and their associated soluble products. To mitigate fouling the application of pulsed short-wavelength ultraviolet (UVC) light (around 254 nm) within the membrane tank together with pre-coagulation was investigated. In mini-pilot-scale tests carried out in parallel with conventional pre-treatment (CUF), the impact of pulsed UV (CUF-UV) at different UV irradiances and fluxes on the increase of trans-membrane pressure (TMP) was evaluated and explained in terms of the quantity and nature of membrane deposits in the membrane cake layer and pores. The results indicated that at a flux of 20 L m -2  h -1 , the pulsed UV (1 min within 31 min cycle) at 3.17 × 10 -2  W/cm 2 prevented any measureable increase in TMP over a period of 32 days, while there was a fourfold increase in TMP for the conventional pre-treatment. For the CUF-UV system the concentration of bacteria and soluble microbial products was much less than the conventional CUF system, and the cake layer was thinner and contained less biopolymers (proteins and polysaccharides). In addition, the pores of the CUF-UV membrane appeared to have less organic deposits, and particularly fractions with a high molecular weight (>10 kDa). At a lower UV irradiance (1.08 × 10 -2  W/cm 2 ), or higher flux (40 L m -2  h -1 ) with the same UV irradiance, there was a measurable increase in TMP, indicating some fouling of the CUF-UV membrane, but the rate of TMP development was significantly lower (∼50%) than the conventional CUF membrane system. Overall, the results show the potential advantages of applying intermittent (pulsed) UVC irradiation with coagulation to control UF membrane fouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preliminary Technology Maturation Plan for Immobilization of High-Level Waste in Glass Ceramics

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

Vienna, John D.; Crum, Jarrod V.; Sevigny, Gary J.

2012-09-30

A technology maturation plan (TMP) was developed for immobilization of high-level waste (HLW) raffinate in a glass ceramics waste form using a cold-crucible induction melter (CCIM). The TMP was prepared by the following process: 1) define the reference process and boundaries of the technology being matured, 2) evaluate the technology elements and identify the critical technology elements (CTE), 3) identify the technology readiness level (TRL) of each of the CTE’s using the DOE G 413.3-4, 4) describe the development and demonstration activities required to advance the TRLs to 4 and 6 in order, and 5) prepare a preliminary plan tomore » conduct the development and demonstration. Results of the technology readiness assessment identified five CTE’s and found relatively low TRL’s for each of them: • Mixing, sampling, and analysis of waste slurry and melter feed: TRL-1 • Feeding, melting, and pouring: TRL-1 • Glass ceramic formulation: TRL-1 • Canister cooling and crystallization: TRL-1 • Canister decontamination: TRL-4 Although the TRL’s are low for most of these CTE’s (TRL-1), the effort required to advance them to higher values. The activities required to advance the TRL’s are listed below: • Complete this TMP • Perform a preliminary engineering study • Characterize, estimate, and simulate waste to be treated • Laboratory scale glass ceramic testing • Melter and off-gas testing with simulants • Test the mixing, sampling, and analyses • Canister testing • Decontamination system testing • Issue a requirements document • Issue a risk management document • Complete preliminary design • Integrated pilot testing • Issue a waste compliance plan A preliminary schedule and budget were developed to complete these activities as summarized in the following table (assuming 2012 dollars). TRL Budget Year MSA FMP GCF CCC CD Overall $M 2012 1 1 1 1 4 1 0.3 2013 2 2 1 1 4 1 1.3 2014 2 3 1 1 4 1 1.8 2015 2 3 2 2 4 2 2.6 2016 2 3 2 2 4 2 4.9 2017 2 3 3 2 4 2 9.8 2018 3 3 3 3 4 3 7.9 2019 3 3 3 3 4 3 5.1 2020 3 3 3 3 4 3 14.6 2021 3 3 3 3 4 3 7.3 2022 3 3 3 3 4 3 8.8 2023 4 4 4 4 4 4 9.1 2024 5 5 5 5 5 5 6.9 2025 6 6 6 6 6 6 6.9 CCC = canister cooling and crystallization; FMP = feeding, melting, and pouring; GCF = glass ceramic formulation; MSA = mixing, sampling, and analyses. This TMP is intended to guide the development of the glass ceramics waste form and process to the point where it is ready for industrialization.« less

Using logic programming for modeling the one-carbon metabolism network to study the impact of folate deficiency on methylation processes.

PubMed

Gnimpieba, Etienne Z; Eveillard, Damien; Guéant, Jean-Louis; Chango, Abalo

2011-08-01

Dynamical modeling is an accurate tool for describing the dynamic regulation of one-carbon metabolism (1CM) with emphasis on the alteration of DNA methylation and/or dUMP methylation into dTMP. Using logic programming we present a comprehensive and adaptative mathematical model to study the impact of folate deficiency, including folate transport and enzymes activities. 5-Methyltetrahydrofolate (5mTHF) uptake and DNA and dUMP methylation were studied by simulating nutritional 5mTHF deficiency and methylenetetrahydrofolate reductase (MTHFR) gene defects. Both conditions had distinct effects on 1CM metabolite synthesis. Simulating severe 5mTHF deficiency (25% of normal levels) modulated 11 metabolites. However, simulating a severe decrease in MTHFR activity (25% of normal activity) modulated another set of metabolites. Two oscillations of varying amplitude were observed at the steady state for DNA methylation with severe 5mTHF deficiency, and the dUMP/dTMP ratio reached a steady state after 2 h, compared to 2.5 h for 100% 5mTHF. MTHFR activity with 25% of V(max) resulted in an increased methylated DNA pool after half an hour. We observed a deviation earlier in the profile compared to 50% and 100% V(max). For dUMP methylation, the highest level was observed with 25%, suggesting a low rate of dUMP methylation into dTMP with 25% of MTHFR activity. In conclusion, using logic programming we were able to construct the 1CM for analyzing the dynamic system behavior. This model may be used to refine biological interpretations of data or as a tool that can provide new hypotheses for pathogenesis.

Separating xylose from glucose using spiral wound nanofiltration membrane: Effect of cross-flow parameters on sugar rejection

NASA Astrophysics Data System (ADS)

Roli, N. F. M.; Yussof, H. W.; Seman, M. N. A.; Saufi, S. M.; Mohammad, A. W.

2016-11-01

A solution model consisted of two different monosaccharides namely xylose and glucose were separated using a pilot scale spiral wound cross-flow system. This system was equipped by a commercial spiral wound nanofiltration (NF) membrane, Desal-5 DK, having a molecular weight cut off (MWCO) of 150-300 g mol-1. The aim of this present work is to investigate the effect of the cross-flow parameters: the trans-membrane pressure (TMP) and the feed concentration (C0) on the xylose separation from glucose. The filtration experiments were carried out in total reflux mode with different feed concentration of 2, 5, and 10 g/L at different TMP of 5,8 and 10 bar. The performances of the NF membrane were evaluated by measuring the permeate flux and sugar rejection for each experiment. All the samples were quantified using a high performance liquid chromatography equipped by a fractive index detector. The experimental results indicated an increase in pressure from 5 to 10 bar which was a notable increase to the permeate fluxes from 2.66 × 10-3 to 4.14 × 10-3L m-2s-1. Meanwhile, an increase in the C0 increases the xylose rejection. At TMP of 10 bar and C0 of 5 g/L, the observed xylose rejection and glucose rejection were measured at 67.19% and 91.82%, respectively. The lower rejection in xylose than glucose suggested that larger glucose molecule were not able to easily pass through the membrane compared to the smaller xylose molecule. The results of this phenomena proved that NF with spiral wound configuration has the potential to separate xylose from glucose, which is valuable to the purification of xylose in xylose production as an alternative to chromatographic processes.

Prediction of Temperatures of Austenite Equilibrium Transformations in Steels During Thermomechanical Processing

NASA Astrophysics Data System (ADS)

Samadian, Pedram; Parsa, Mohammad Habibi; Ahmadabadi, M. Nili; Mirzadeh, Hamed

2014-10-01

Knowledge about the transformation temperatures is crucial in processing of steels especially in thermomechanical processes because microstructures and mechanical properties after processing are closely related to the extent and type of transformations. The experimental determination of critical temperatures is costly, and therefore, it is preferred to predict them by mathematical methods. In the current work, new thermodynamically based models were developed for computing the Ae3 and Acm temperatures in the equilibrium cooling conditions when austenite is deformed at elevated temperatures. The main advantage of the proposed models is their capability to predict the temperatures of austenite equilibrium transformations in steels with total alloying elements (Mn + Si + Ni + Cr + Mo + Cu) less than 5 wt.% and Si less than 1 wt.% under the deformation conditions just by using the chemical potential of constituents, without the need for determining the total Gibbs free energy of steel which requires many experiments and computations.

Shape Memory Characteristics of Ti(sub 49.5)Ni(sub 25)Pd(sub 25)Sc(sub 0.5) High-Temperature Shape Memory Alloy After Severe Plastic Deformation

NASA Technical Reports Server (NTRS)

Atli, K. C.; Karaman, I.; Noebe, R. D.; Garg, A.; Chumlyakov, Y. I.; Kireeva, I. V.

2011-01-01

A Ti(49.5)Ni25Pd25Sc(0.5) high-temperature shape memory alloy is thermomechanically processed to obtain enhanced shape-memory characteristics: in particular, dimensional stability upon repeated thermal cycles under constant loads. This is accomplished using severe plastic deformation via equal channel angular extrusion (ECAE) and post-processing annealing heat treatments. The results of the thermomechanical experiments reveal that the processed materials display enhanced shape memory response, exhibiting higher recoverable transformation and reduced irrecoverable strain levels upon thermal cycling compared with the unprocessed material. This improvement is attributed to the increased strength and resistance of the material against defect generation upon phase transformation as a result of the microstructural refinement due to the ECAE process, as supported by the electron microscopy observations.

Effect of rumen-protected methionine on feed intake, milk production, true milk protein concentration, and true milk protein yield, and the factors that influence these effects: a meta-analysis.

PubMed

Patton, R A

2010-05-01

A meta-analysis of published studies was used to investigate the effect of rumen-protected methionine (RPM) added to the diets of lactating dairy cattle on dry matter intake, milk production, true milk protein (TMP) production, and milk fat yield. Differences in responses between 2 commonly used RPM products, Mepron (Evonik Industries, Hanau, Germany) and Smartamine (Adisseo, Antony, France), were investigated as well as dietary and animal factors that could influence responses. Diets were coded with respect to the amino acid (AA) deficiency of the control diet as predicted by the AminoCow model (version 3.5.2, http://www.makemilknotmanure.com/aminocow.php; 0=no AA deficiency, 1=Met deficiency, 2=Met and Lys deficiency, 3=Met and Lys plus at least 1 other AA deficiency) to test the effect of AA deficiencies on RPM response. Thirty-five studies were identified, 17 studies evaluating Mepron, 18 studies evaluating Smartamine, and 1 study evaluating both. This permitted 75 dietary comparisons between control and RPM-added diets. Diets were entered into the AminoCow and the 2001 National Research Council models to compare predictions of Met, Lys, and metabolizable protein (MP) flow. Mean Met and Lys in diets where RPM was fed were estimated to be 2.35 and 6.33% of MP, respectively. Predictions of flows between models were similar. Overall, RPM addition to diets increased production of TMP, both as percentage (0.07%) and yield (27 g/d). Dry matter intake and milk fat percentage were slightly decreased, whereas milk production was slightly increased. Differences between products were detected for all production variables, with Mepron-fed cows producing less TMP percentage but greater milk production, resulting in twice as much TMP yield. Milk protein response to RPM was not related to predicted AA deficiency, calculated Met deficiency, or Met as a percentage of MP. Other dietary factors, including Lys flow (g/d), Lys as percentage of MP, neutral detergent fiber percentage, crude protein percentage, or energy balance, had no detectable effects on TMP response. When cows with a predicted positive AA balance were fed RPM, milk production increased, but when AA balance was negative, milk production decreased. Amount of RPM added to the diet was not correlated to TMP response. This study does not support the necessity of a high Lys level as a prerequisite to obtaining a TMP response to feeding RPM or the MP requirement suggested by the National Research Council model (2001). However, more dose-response studies over a wide range of milk production and dietary regimens will be required to more clearly establish AA requirements and to predict responses to RPM supplementation. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Asymmetrical Transmembrane Potential in Intracellular Organelles of Adrenal Chromatin Cells Exposed to Nanosecond Electric Pulses

NASA Astrophysics Data System (ADS)

Aramendia Zabaleta, Guillermo Jose

In our research on exploring the effects of 5 ns, high intensity electric pulses on neurosecretory adrenal chromaffin cells, cell modeling has played an important role in understanding and explaining the experimental results. Externally applied nanosecond-duration electric pulses (NEPs) can affect cells by creating nanopores in the cell and intracellular organelle membranes, making these membranes permeable to certain ions. A chromaffin cell contains, at a minimum, 7000 secretory granules plus other organelles such as mitochondria and the endoplasmic reticulum. In all the biological cell models constructed in the literature, there is no evidence of asymmetrical Transmembrane Potential (TMP) distribution in the intracellular membranes. However, these models do not include a realistic number of intracellular organelles. The goal of this research was to construct a more realistic cell model that incorporates a large number of secretory granules in the cytosol. To this end, a beta-version of the real-valued unstructured mesh Finite Element Method (FEM) electro-quasi-static module in Sim4life (SPEAG, Switzerland) has been used to model a chromaffin cell in which 1000 secretory granules are included in the cytosol. The model is, we believe, the most detailed geometrical cell model developed. It includes a spherical chromaffin cell (radius 8 mum), nucleus (radius 2.5 mum) located off-center, 500 granules (radius 200 nm) randomly located within a distance of 2 mum from the surface of the nucleus, and additional 500 granules randomly located in the remaining region of the cytosol. Cell and granule membrane thickness was set to 5 nm and nuclear membrane thickness to 10 nm. Dielectric properties of all constituents of the model were obtained from the literature or measured. Because the FEM Low Frequency solver is a quasi-static solver and not capable of accepting a time-varying pulse as input, all computations have been performed at single frequencies in the range DC to 60 MHz, sampled from the Fourier spectrum of the actual 5 ns pulse used in experiments. Electric field and TMP distributions have been computed in the cell model as a function of frequency, granule radius, and orientation of the applied E-field. Results show that granules located in the vicinity of the equatorial side of the nucleus had a higher TMP magnitude than the rest of the granules. In contrast, granules located in the vicinity of the poles of the nucleus had a lower TMP magnitude. The TMP distribution in the granules was strongly dependent on their location with respect to the nucleus and could exhibit asymmetries. Clearly, the nucleus had an influence on the TMP of the surrounding granules and the region of influence extended to a radial distance of 2 mu m from the nucleus. Creating a realistic model of a chromaffin cell is fundamental in order to estimate the TMP and electric field in a chromaffin cell. Such knowledge is important for understanding the impact of NEPs on the modulation of hormone secretion.

Analysis of the conduction mechanism and dielectric properties of N, N', N" tris(4-methylphenyl)phosphoric triamide

NASA Astrophysics Data System (ADS)

Ali, H. A. M.

2016-03-01

The structure for the powder of N,N', N"-tris(4-methylphenyl)phosphoric triamide, TMP-TA, was characterized using X-ray diffraction (XRD) and differential thermal analysis (DTA) techniques. The ac conductivity and dielectric properties were measured in the frequency range of 42-105 Hz for the bulk TMP-TA in a pellet form at different temperatures. The frequency dependence of ac conductivity was expressed by a Jonscher's universal power law. The frequency exponent (s) was determined from the fitting of experimental data of ac conductivity. The correlated barrier hopping (CBH) model was found to be responsible for the ac conduction mechanism in TMP-TA. The activation energy was calculated from the temperature dependence of ac conductivity. The values of the density of states at the Fermi level were determined for different frequencies. The components of the electric modulus (M' and M") were calculated and used to estimate the relaxation time.

Doped silicon nanocrystals from organic dopant precursor by a SiCl4-based high frequency nonthermal plasma

NASA Astrophysics Data System (ADS)

Zhou, Shu; Ding, Yi; Pi, Xiaodong; Nozaki, Tomohiro

2014-11-01

Doped silicon nanocrystals (Si NCs) are of great interest in demanding low-cost nanodevices because of the abundance and nontoxicity of Si. Here, we demonstrate a cost-effective gas phase approach to synthesize phosphorous (P)-doped Si NCs in which the precursors used, i.e., SiCl4, trimethyl phosphite (TMP), are both safe and economical. It is found that the TMP-enabled P-doping does not change the crystalline structure of Si NCs. The surface of P-doped Si NCs is terminated by both Cl and H. The Si-H bond density at the surface of P-doped Si NCs is found to be much higher than that of undoped Si NCs. The X-ray photoelectron spectroscopy and electron spin resonance results indicate that P atoms are doped into the substitutional sites of the Si-NC core and electrically active in Si NCs. Unintentional impurities, such as carbon contained in TMP, are not introduced into Si NCs.

Chemical degradation of trimethyl phosphate as surrogate for organo-phosporus pesticides on nanostructured metal oxides

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

Štengl, Václav, E-mail: stengl@iic.cas.cz; Henych, Jiří; Grygar, Tomáš

Nanostructured TiO{sub 2} and mixed oxides of Ti and Fe, Hf, In, Mn or Zr -were prepared by homogeneous hydrolysis of aqueous solution of metal sulphates with urea. The oxides were characterised by X-ray powder diffraction (XRD), scanning electron microscopy, particle size distribution, surface area and porosity. The oxide materials consists of a few nanometre primary crystals (mainly anatase) arranged in a few micrometre regular spherical agglomerates with specific surface area 133–511 m{sup 2} g{sup −1}. The FTIR diffuse spectroscopy was used for monitoring chemical degradation of trimethylphosphate (TMP) as a surrogate for organo-phosphorus pesticides under ambient and higher temperatures.more » Undoped TiO{sub 2} and Ti,Mn-mixed oxide were most active in cleavage (hydrolysis) of CH{sub 3}O from TMP at room temperature and 100 °C. Cleavage of CH{sub 3}O in the other studied mixed oxides was not complete until temperature exceeds the boiling point of TMP.« less

Global distribution and epidemiologic associations of Escherichia coli clonal group A, 1998-2007.

PubMed

Johnson, James R; Menard, Megan E; Lauderdale, Tsai-Ling; Kosmidis, Chris; Gordon, David; Collignon, Peter; Maslow, Joel N; Andrasević, Arjana Tambić; Kuskowski, Michael A

2011-11-01

Escherichia coli clonal group A (CGA) was first reported in 2001 as an emerging multidrug-resistant extraintestinal pathogen. Because CGA has considerable implications for public health, we examined the trends of its global distribution, clinical associations, and temporal prevalence for the years 1998-2007. We characterized 2,210 E. coli extraintestinal clinical isolates from 32 centers on 6 continents by CGA status for comparison with trimethoprim/sulfamethoxazole (TMP/SMZ) phenotype, specimen type, inpatient/outpatient source, and adult/child host; we adjusted for clustering by center. CGA prevalence varied greatly by center and continent, was strongly associated with TMP/SMZ resistance but not with other epidemiologic variables, and exhibited no temporal prevalence trend. Our findings indicate that CGA is a prominent, primarily TMP/SMZ-resistant extraintestinal pathogen concentrated within the Western world, with considerable pathogenic versatility. The stable prevalence of CGA over time suggests full emergence by the late 1990s, followed by variable endemicity worldwide as an antimicrobial drug-resistant public health threat.

Harvesting microalgal biomass using crossflow membrane filtration: critical flux, filtration performance, and fouling characterization.

PubMed

Elcik, Harun; Cakmakci, Mehmet

2017-06-01

The purpose of this study was to investigate the efficient harvesting of microalgal biomass through crossflow membrane filtration. The microalgal biomass harvesting experiments were performed using one microfiltration membrane (pore size: 0.2 µm, made from polyvinylidene fluoride) and three ultrafiltration membranes (molecular weight cut-off: 150, 50, and 30 kDa, made from polyethersulfone, hydrophilic polyethersulfone, and regenerated cellulose, respectively). Initially, to minimize membrane fouling caused by microalgal cells, experiments with the objective of determining the critical flux were performed. Based on the critical flux calculations, the best performing membrane was confirmed to be the UH050 membrane, produced from hydrophilic polyethersulfone material. Furthermore, we also evaluated the effect of transmembrane pressure (TMP) and crossflow velocity (CFV) on filtration flux. It was observed that membrane fouling was affected not only by the membrane characteristics, but also by the TMP and CFV. In all the membranes, it was observed that increasing CFV was associated with increasing filtration flux, independent of the TMP.

Entropy production in mesoscopic stochastic thermodynamics: nonequilibrium kinetic cycles driven by chemical potentials, temperatures, and mechanical forces

NASA Astrophysics Data System (ADS)

Qian, Hong; Kjelstrup, Signe; Kolomeisky, Anatoly B.; Bedeaux, Dick

2016-04-01

Nonequilibrium thermodynamics (NET) investigates processes in systems out of global equilibrium. On a mesoscopic level, it provides a statistical dynamic description of various complex phenomena such as chemical reactions, ion transport, diffusion, thermochemical, thermomechanical and mechanochemical fluxes. In the present review, we introduce a mesoscopic stochastic formulation of NET by analyzing entropy production in several simple examples. The fundamental role of nonequilibrium steady-state cycle kinetics is emphasized. The statistical mechanics of Onsager’s reciprocal relations in this context is elucidated. Chemomechanical, thermomechanical, and enzyme-catalyzed thermochemical energy transduction processes are discussed. It is argued that mesoscopic stochastic NET in phase space provides a rigorous mathematical basis of fundamental concepts needed for understanding complex processes in chemistry, physics and biology. This theory is also relevant for nanoscale technological advances.

Thermomechanical processing of HAYNES alloy No. 188 sheet to improve creep strength

NASA Technical Reports Server (NTRS)

Klarstrom, D. L.

1978-01-01

Improvements in the low strain creep strength of HAYNES alloy No. 188 thin gauge sheet by means of thermomechanical processing were developed. Processing methods designed to develop a sheet with strong crystallographic texture after recrystallization and to optimize grain size were principally studied. The effects of thickness-to-grain diameter ratio and prestrain on low strain creep strength were also briefly examined. Results indicate that the most significant improvements were obtained in the sheets having a strong crystallographic texture. The low strain creep strength of the textured sheets was observed to be superior to that of standard production sheets in the 922 K to 1255 K temperature range. Tensile, stress rupture, fabricability, and surface stability properties of the experimental sheets were also measured and compared to property values reported for the baseline production sheets.

Effect of thermomechanical processing on the microstructure and retained austenite stability during in situ tensile testing using synchrotron x-ray diffraction of NbMoAI TRIP steel.

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

Pereloma, E.; Zhang, L.; Liss, K.-D.

2011-06-01

In this work we compare and contrast the stability of retained austenite during tensile testing of Nb-Mo-Al transformation-induced plasticity steel subjected to different thermomechanical processing schedules. The obtained microstructures were characterised using optical metallography, transmission electron microscopy and X-ray diffraction. The transformation of retained austenite to martensite under tensile loading was observed by in-situ high energy X-ray diffraction at 1ID / APS. It has been shown that the variations in the microstructure of the steel, such as volume fractions of present phases, their morphology and dimensions, play a critical role in the strain-induced transition of retained austenite to martensite.

Modeling and FE Simulation of Quenchable High Strength Steels Sheet Metal Hot Forming Process

NASA Astrophysics Data System (ADS)

Liu, Hongsheng; Bao, Jun; Xing, Zhongwen; Zhang, Dejin; Song, Baoyu; Lei, Chengxi

2011-08-01

High strength steel (HSS) sheet metal hot forming process is investigated by means of numerical simulations. With regard to a reliable numerical process design, the knowledge of the thermal and thermo-mechanical properties is essential. In this article, tensile tests are performed to examine the flow stress of the material HSS 22MnB5 at different strains, strain rates, and temperatures. Constitutive model based on phenomenological approach is developed to describe the thermo-mechanical properties of the material 22MnB5 by fitting the experimental data. A 2D coupled thermo-mechanical finite element (FE) model is developed to simulate the HSS sheet metal hot forming process for U-channel part. The ABAQUS/explicit model is used conduct the hot forming stage simulations, and ABAQUS/implicit model is used for accurately predicting the springback which happens at the end of hot forming stage. Material modeling and FE numerical simulations are carried out to investigate the effect of the processing parameters on the hot forming process. The processing parameters have significant influence on the microstructure of U-channel part. The springback after hot forming stage is the main factor impairing the shape precision of hot-formed part. The mechanism of springback is advanced and verified through numerical simulations and tensile loading-unloading tests. Creep strain is found in the tensile loading-unloading test under isothermal condition and has a distinct effect on springback. According to the numerical and experimental results, it can be concluded that springback is mainly caused by different cooling rats and the nonhomogengeous shrink of material during hot forming process, the creep strain is the main factor influencing the amount of the springback.

Genetic requirements for sensitivity of bacteriophage t7 to dideoxythymidine.

PubMed

Tran, Ngoc Q; Tabor, Stanley; Richardson, Charles C

2014-08-01

We previously reported that the presence of dideoxythymidine (ddT) in the growth medium selectively inhibits the ability of bacteriophage T7 to infect Escherichia coli by inhibiting phage DNA synthese (N. Q. Tran, L. F. Rezende, U. Qimron, C. C. Richardson, and S. Tabor, Proc. Natl. Acad. Sci. U. S. A. 105:9373-9378, 2008, doi:10.1073/pnas.0804164105). In the presence of T7 gene 1.7 protein, ddT is taken up into the E. coli cell and converted to ddTTP. ddTTP is incorporated into DNA as ddTMP by the T7 DNA polymerase, resulting in chain termination. We have identified the pathway by which exogenous ddT is converted to ddTTP. The pathway consists of ddT transport by host nucleoside permeases and phosphorylation to ddTMP by the host thymidine kinase. T7 gene 1.7 protein phosphorylates ddTMP and ddTDP, resulting in ddTTP. A 74-residue peptide of the gene 1.7 protein confers ddT sensitivity to the same extent as the 196-residue wild-type gene 1.7 protein. We also show that cleavage of thymidine to thymine and deoxyribose-1-phosphate by the host thymidine phosphorylase greatly increases the sensitivity of phage T7 to ddT. Finally, a mutation in T7 DNA polymerase that leads to discrimination against the incorporation of ddTMP eliminates ddT sensitivity. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Genetic Requirements for Sensitivity of Bacteriophage T7 to Dideoxythymidine

PubMed Central

Tran, Ngoc Q.; Tabor, Stanley

2014-01-01

We previously reported that the presence of dideoxythymidine (ddT) in the growth medium selectively inhibits the ability of bacteriophage T7 to infect Escherichia coli by inhibiting phage DNA synthese (N. Q. Tran, L. F. Rezende, U. Qimron, C. C. Richardson, and S. Tabor, Proc. Natl. Acad. Sci. U. S. A. 105:9373–9378, 2008, doi:10.1073/pnas.0804164105). In the presence of T7 gene 1.7 protein, ddT is taken up into the E. coli cell and converted to ddTTP. ddTTP is incorporated into DNA as ddTMP by the T7 DNA polymerase, resulting in chain termination. We have identified the pathway by which exogenous ddT is converted to ddTTP. The pathway consists of ddT transport by host nucleoside permeases and phosphorylation to ddTMP by the host thymidine kinase. T7 gene 1.7 protein phosphorylates ddTMP and ddTDP, resulting in ddTTP. A 74-residue peptide of the gene 1.7 protein confers ddT sensitivity to the same extent as the 196-residue wild-type gene 1.7 protein. We also show that cleavage of thymidine to thymine and deoxyribose-1-phosphate by the host thymidine phosphorylase greatly increases the sensitivity of phage T7 to ddT. Finally, a mutation in T7 DNA polymerase that leads to discrimination against the incorporation of ddTMP eliminates ddT sensitivity. PMID:24858186

The application of nitric oxide to control biofouling of membrane bioreactors

PubMed Central

Luo, Jinxue; Zhang, Jinsong; Barnes, Robert J; Tan, Xiaohui; McDougald, Diane; Fane, Anthony G; Zhuang, Guoqiang; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

2015-01-01

A novel strategy to control membrane bioreactor (MBR) biofouling using the nitric oxide (NO) donor compound PROLI NONOate was examined. When the biofilm was pre-established on membranes at transmembrane pressure (TMP) of 88–90 kPa, backwashing of the membrane module with 80 μM PROLI NONOate for 45 min once daily for 37 days reduced the fouling resistance (Rf) by 56%. Similarly, a daily, 1 h exposure of the membrane to 80 μM PROLI NONOate from the commencement of MBR operation for 85 days resulted in reduction of the TMP and Rf by 32.3% and 28.2%. The microbial community in the control MBR was observed to change from days 71 to 85, which correlates with the rapid TMP increase. Interestingly, NO-treated biofilms at 85 days had a higher similarity with the control biofilms at 71 days relative to the control biofilms at 85 days, indicating that the NO treatment delayed the development of biofilm bacterial community. Despite this difference, sequence analysis indicated that NO treatment did not result in a significant shift in the dominant fouling species. Confocal microscopy revealed that the biomass of biopolymers and microorganisms in biofilms were all reduced on the PROLI NONOate-treated membranes, where there were reductions of 37.7% for proteins and 66.7% for microbial cells, which correlates with the reduction in TMP. These results suggest that NO treatment could be a promising strategy to control biofouling in MBRs. PMID:25752591

Ultrafiltration technology with a ceramic membrane for reactive dye removal: optimization of membrane performance.

PubMed

Alventosa-deLara, E; Barredo-Damas, S; Alcaina-Miranda, M I; Iborra-Clar, M I

2012-03-30

An ultrafiltration (UF) ceramic membrane was used to decolorize Reactive Black 5 (RB5) solutions at different dye concentrations (50 and 500 mg/L). Transmembrane pressure (TMP) and cross-flow velocity (CFV) were modified to study their influence on initial and steady-state permeate flux (J(p)) and dye rejection (R). Generally, J(p) increased with higher TMP and CFV and lower feed concentration, up to a maximum steady-state J(p) of 266.81 L/(m(2)h), obtained at 3 bar, 3m/s and 50mg/L. However, there was a TMP value (which changed depending on operating CFV and concentration) beyond which slight or no further increase in steady-state J(p) was observed. Similarly, the higher the CFV was, the more slightly the steady-state J(p) increased. Furthermore, the effectiveness of ultrafiltration treatment was evaluated through dye rejection coefficient. The results showed significant dye removals, regardless of the tested conditions, with steady-state R higher than 79.8% for the 50mg/L runs and around 73.2% for the 500 mg/L runs. Finally response surface methodology (RSM) was used to optimize membrane performance. At 50mg/L, a TMP of 4 bar and a CFV of 2.53 m/s were found to be the conditions giving the highest steady-state J(p), 255.86 L/(m(2)h), and the highest R, 95.2% simultaneously. Copyright © 2012 Elsevier B.V. All rights reserved.

Metal exposure in cows grazing pasture contaminated by iron industry: Insights from magnetic particles used as tracers.

PubMed

Ayrault, Sophie; Catinon, Mickaël; Boudouma, Omar; Bordier, Louise; Agnello, Gregory; Reynaud, Stéphane; Tissut, Michel

2016-05-01

Magnetic particles (MP) emitted by an iron smelter were used to investigate the exposure of cows grazing on a grassland polluted by these MP and by large amounts of potentially toxic elements (PTE). The morphology as well as the chemical composition of the MP separated from cow dung were studied. Large amounts of typical MP were found (1.1 g kg(-1) dry weight) in the cow dung sampled from the exposed site, whereas these particles were absent from the reference unpolluted site. The ingested MP were mainly technogenic magnetic particles (TMP) emitted by the smelter. Considering the MP concentration in the grazed grass on the exposed site, it was concluded that cows absorb the MP not only from the grass but also from the soil surface. The results of a mild acidic leaching of the MP suggested that the particles were possibly submitted to a superficial dissolution in the abomasum, pointing at a potential route of transfer of the PTE originating from the TMP and leading into food chains. TMP were only a small part of the anthropogenic contamination having affected the soil and the dung. However, due to their unequivocal signature, TMP are a powerful tracer of the distribution of PTE in the different compartments constituting the food chains and the ecosystems. Furthermore, the measurement of the particle sizes gave evidence that a noticeable proportion of the MP could enter the respiratory tract. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis on annealing-induced stress of blind-via TSV using FEM

NASA Astrophysics Data System (ADS)

Shao, Jie; Shi, Tielin; Du, Li; Su, Lei; Lu, Xiangning; Liao, Guanglan

2017-07-01

Copper-filled through silicon via (TSV) is a promising material owing to its application in high-density three-dimensional (3D) packaging. However, in TSV manufacturing, thermo-mechanical stress is induced during the annealing process, often causing reliability issues. In this paper, the finite element method is employed to investigate the impacts of via shape and SiO2 liner uniformity on the thermo-mechanical properties of copper- filled blind-via TSV after annealing. Top interface stress analysis on the TSV structure shows that the curvature of via openings releases stress concentration that leads to 60 MPa decrease of normal stresses, σ xx and σ yy , in copper and 70 MPa decrease of σ xx in silicon. Meanwhile, the vertical interface analysis shows that annealing-induced stress at the SiO2/Si interface depends heavily on SiO2 uniformity. By increasing the thickness of SiO2 linear, the stress at the vertical interface can be significantly reduced. Thus, process optimization to reduce the annealing-induced stress becomes feasible. The results of this study help us gain a better understanding of the thermo-mechanical behavior of the annealed TSV in 3D packaging.

Structure and Properties of Ti-19.7Nb-5.8Ta Shape Memory Alloy Subjected to Thermomechanical Processing Including Aging

NASA Astrophysics Data System (ADS)

Dubinskiy, S.; Brailovski, Vladimir; Prokoshkin, S.; Pushin, V.; Inaekyan, K.; Sheremetyev, V.; Petrzhik, M.; Filonov, M.

2013-09-01

In this work, the ternary Ti-19.7Nb-5.8Ta (at.%) alloy for biomedical applications was studied. The ingot was manufactured by vacuum arc melting with a consumable electrode and then subjected to hot forging. Specimens were cut from the ingot and processed by cold rolling with e = 0.37 of logarithmic thickness reduction and post-deformation annealing (PDA) between 400 and 750 °C (1 h). Selected samples were subjected to aging at 300 °C (10 min to 3 h). The influence of the thermomechanical processing on the alloy's structure, phase composition, and mechanical and functional properties was studied. It was shown that thermomechanical processing leads to the formation of a nanosubgrained structure (polygonized with subgrains below 100 nm) in the 500-600 °C PDA range, which transforms to a recrystallized structure of β-phase when PDA temperature increases. Simultaneously, the phase composition and the β → α″ transformation kinetics vary. It was found that after conventional cold rolling and PDA, Ti-Nb-Ta alloy manifests superelastic and shape memory behaviors. During aging at 300 °C (1 h), an important quantity of randomly scattered equiaxed ω-precipitates forms, which results in improved superelastic cyclic properties. On the other hand, aging at 300 °C (3 h) changes the ω-precipitates' particle morphology from equiaxed to elongated and leads to their coarsening, which negatively affects the superelastic and shape memory functional properties of Ti-Nb-Ta alloy.

Degradation of trans-polyisoprene after root filling with thermoplasticized techniques.

PubMed

Maniglia-Ferreira, C; Bönecker, G; Silva, J B A; de Paula, R C M; Feitosa, J P A; Souza-Filho, F J

2008-04-01

To evaluate ex vivo degradation of gutta-percha following six thermoplastic obturation techniques. Ninety human-extracted mandibular premolars were selected and divided randomly into nine groups for filling. Group 1: thermomechanical compaction for 3 s with Konne gutta-percha points (Konne Ind. e Com. de Mat. Odontol., Belo Horizonte, MG, Brazil); Group 2: thermomechanical compaction for 3 s with Dentsply TP gutta-percha points (Dentsply Indústria e Comércio Ltda, Petrópolis, R.J. Brazil); Group 3: thermomechanical compaction for 10 s with Konne; Group 4: thermomechanical compaction for 10 s with Dentsply TP; Group 5: warm vertical condensation using System B (EIE/Analytic, Richmond, WA, USA) with Konne; Group 6: warm vertical condensation using System B with Dentsply TP; Group 7: vertical condensation with Konne; Group 8: vertical condensation with Dentsply TP; Group 9: Microseal cone (Analytic Endodontics, Glendora, CA, USA). A further four groups were assessed without using teeth, Group 10: Microseal microflow (Analytic Endodontics); Group 11: Obtura (Obtura Corporation, Penton, MO, USA); Group 12: Obtura flow (Obtura Corporation); Group 13: Thermafil (Dentsply Maillefer, Tulsa, OK, USA). The filling material was removed from the root canal and trans-1,4-polyisoprene isolated by solubilization of the root filling remnants in chloroform followed by filtration and centrifugation. By gel permeation chromatography and infrared spectroscopy, the occurrence and degree of degradation were assessed. The results were analysed statistically using the Kruskal-Wallis test. With differential scanning calorimetry, the thermal behaviour of the gutta-percha was determined. A significant decrease in polymer molar mass and the production of carboxyl and hydroxyl groups in the polymer were observed with thermomechanical compaction used for 10 s and vertical condensation filling techniques (P = 0.0001 and P = 0.0005, respectively). Other techniques caused no polymer degradation. Polyisoprene degrades with high temperature. Thermomechanical compaction for 10 s and vertical condensation were associated with the greatest degradative process.

Structural Effects in Lithiocuprate Chemistry: The Elucidation of Reactive Pentametallic Complexes

PubMed Central

Harford, Philip J; Peel, Andrew J; Taylor, Joseph P; Komagawa, Shinsuke; Raithby, Paul R; Robinson, Thomas P; Uchiyama, Masanobu; Wheatley, Andrew E H

2014-01-01

TMPLi (TMP=2,2,6,6-tetramethylpiperidide) reacts with CuI salts in the presence of Et2O to give the dimers [{(TMP)2Cu(X)Li2(OEt2)}2] (X=CN, halide). In contrast, the use of DMPLi (DMP=cis-2,6-dimethylpiperidide) gives an unprecedented structural motif; [{(DMP)2CuLi(OEt2)}2LiX] (X=halide). This formulation suggests a hitherto unexplored route to the in situ formation of Gilman-type bases that are of proven reactivity in directed ortho cupration. PMID:24550148

Can Levofloxacin Be a Useful Alternative to Trimethoprim-Sulfamethoxazole for Treating Stenotrophomonas maltophilia Bacteremia?

PubMed Central

Cho, Sun Young; Kim, Jungok; Ha, Young Eun; Chung, Doo Ryeon; Lee, Nam Yong; Peck, Kyong Ran; Song, Jae-Hoon

2014-01-01

A retrospective study was conducted to evaluate the efficacy of levofloxacin in the treatment of Stenotrophomonas maltophilia bacteremia. The 30-day mortality rates were similar between the trimerthoprim-sulfamethoxazole (TMP-SMX) and levofloxacin treatment groups. Adverse events related to antibiotics occurred more frequently in patients receiving TMP-SMX, and recurrent bacteremia due to levofloxacin-resistant S. maltophilia strains developed in patients treated with levofloxacin. Our data suggest that levofloxacin can be a useful alternative option for treating S. maltophilia infections. PMID:24126583

Acronyms and effacement: traditional medical practitioners (TMP) in international health development.

PubMed

Pigg, S L

1995-07-01

International development draws on a globalized vision of 'traditional medicine' when constructing country-specific programs that use local practitioners to further health objectives. This paper looks at the tension between this mobile notion of 'the traditional' and the local social ground. Categories such as traditional birth attendant (TBA) and traditional medical practitioner (TMP) emerge from a process of translation that links local realities to development in specific ways. Examination of training programs for two kinds of 'indigenous practitioners' in Nepal--birth attendants and shamans--shows that various Nepalese specialists are constructed as TBAs and TMPs in a discursive process that emphasizes some differences while eliding others. The acronyms TBA and TMP encapsulate numerous acts of translation through which diverse local practices are subsumed into an overarching development framework. The many layers of this process include: how 'traditional healers' are understood in international health policy; how, in national planning, these conceptions are made to fit with existing Nepalese healers; and how research on 'local ideas and practices' becomes authoritative knowledge about 'traditions', which then, in turn, form a basis for the planning and implementation of training programs. The conceptual categories evident in development discourse on 'traditional healers' take concrete, practical form in the design and implementation of training programs. At the same time development attempts to create programs tailored to local conditions, it generates frameworks that efface or exclude much of what local people think, believe and do. Although training programs for TBAs and TMPs have been advocated as a way to 'bridge the gap' between the realities of local peoples lives and development institutions' visions, it is important to realize that, at another level, development discourse produces the very problems it aims to solve. The case study of training programs for TMPs and TBAs in Nepal shows how the universalizing principles inherent in development discourse systematically dismantle and decontextualize different socio-cultural realities in the course of taking them into account. Development institutions are thus positioned as authoritative mediators of all local worlds. Translation is a social act that, through the management of the circulation of discourses, reinforces the particular global-local power relations of international development. Relations of power, as well as states of health, are at stake in health development encounters. This paper questions whether health development can achieve its humanitarian goals within the existing conceptual framework.

Effect of Thermomechanical Processing on Microstructure, Texture Evolution, and Mechanical Properties of Al-Mg-Si-Cu Alloys with Different Zn Contents

NASA Astrophysics Data System (ADS)

Wang, X. F.; Guo, M. X.; Chen, Y.; Zhu, J.; Zhang, J. S.; Zhuang, L. Z.

2017-07-01

The effect of thermomechanical processing on microstructure, texture evolution, and mechanical properties of Al-Mg-Si-Cu alloys with different Zn contents was studied by mechanical properties, microstructure, and texture characterization in the present study. The results show that thermomechanical processing has a significant influence on the evolution of microstructure and texture and on the final mechanical properties, independently of Zn contents. Compared with the T4P-treated (first preaged at 353 K (80 °C) for 12 hours and then naturally aged for 14 days) sheets with high final cold rolling reduction, the T4P-treated sheets with low final cold rolling reduction possess almost identical strength and elongation and higher average r values. Compared with the intermediate annealed sheets with high final cold rolling reduction, the intermediate annealed sheets with low final cold rolling reduction contain a higher number of particles with a smaller size. After solution treatment, in contrast to the sheets with high final cold rolling reduction, the sheets with low final cold rolling reduction possess finer grain structure and tend to form a weaker recrystallization texture. The recrystallization texture may be affected by particle distribution, grain size, and final cold rolling texture. Finally, the visco-plastic self-consistent (VPSC) model was used to predict r values.

Microstructural Evolution and Constitutive Relationship of M350 Grade Maraging Steel During Hot Deformation

NASA Astrophysics Data System (ADS)

Chakravarthi, K. V. A.; Koundinya, N. T. B. N.; Narayana Murty, S. V. S.; Nageswara Rao, B.

2017-03-01

Maraging steels exhibit extraordinary strength coupled with toughness and are therefore materials of choice for critical structural applications in defense, aerospace and nuclear engineering. Thermo-mechanical processing is an important step in the manufacture of these structural components. This process assumes significance as these materials are expensive and the mechanical properties obtained depend on the microstructure evolved during thermo-mechanical processing. In the present study, M350 grade maraging steel specimens were hot isothermally compressed in the temperature range of 900-1200 °C and in the strain rate range of 0.001-100 s-1, and true stress-true strain curves were generated. The microstructural evolution as a function of strain rate and temperature in the deformed compression specimens was studied. The effect of friction between sample and compression dies was evaluated, and the same was found to be low. The measured flow stress data was used for the development of a constitutive model to represent the hot deformation behavior of this alloy. The proposed equation can be used as an input in the finite element analysis to obtain the flow stress at any given strain, strain rate, and temperature useful for predicting the flow localization or fracture during thermo-mechanical simulation. The activation energy for hot deformation was calculated and is found to be 370.88 kJ/mol, which is similar to that of M250 grade maraging steel.

Study of Carbide Evolution During Thermo-Mechanical Processing of AISI D2 Tool Steel

NASA Astrophysics Data System (ADS)

Bombac, D.; Fazarinc, M.; Podder, A. Saha; Kugler, G.

2013-03-01

The microstructure of a cold-worked tool steel (AISI D2) with various thermo-mechanical treatments was examined in the current study to identify the effects of these treatments on phases. X-ray diffraction was used to identify phases. Microstructural changes such as spheroidization and coarsening of carbides were studied. Thermodynamic calculations were used to verify the results of the differential thermal analysis. It was found that soaking temperature and time have a large influence on dissolution, precipitation, spheroidization, and coalescence of carbides present in the steel. This consequently influences the hot workability and final properties.

The effect of thermo-mechanical processing on physical properties of processed amaranth and oat bran composites

USDA-ARS?s Scientific Manuscript database

Amaranth-oat composites were developed using gluten free amaranth flour containing essential amino acids and minerals with oat products containing ß-glucan, known for lowering blood cholesterol. Amaranth flour and oat bran concentrate (OBC) composites (1:4) were processed using different technologie...

Network Security and the NPS Internet Firewall.

DTIC Science & Technology

1994-09-16

NIS between clients and servers. The ypxfr service is used for trans- Network Information ferring the /etc/ passwd file from the master server to the...slave Service servers. If the NIS domain name is guessed, an outsider can get a copy of the /etc/ passwd file. Table 5: Network Services With Known...TCP ports 20 and 21), for the ftp network service: outside% ftp 131.120.50.151 ftp> get /etc/ passwd /tmp/passwd.inside (login process...) ftp> cd nttcp

Thermomechanical deformation behavior of a dynamic strain aging alloy, Hastelloy X

NASA Technical Reports Server (NTRS)

Castelli, Michael G.; Miner, Robert V.; Robinson, David N.

1992-01-01

An experimental study was performed to identify the effects of dynamic strain aging (solute drag) and metallurgical instabilities under thermomechanical loading conditions. The study involved a series of closely controlled thermomechanical deformation tests on the solid-solution-strenghened nickel-base superalloy, Hastelloy X. This alloy exhibits a strong isothermal strain aging peak at approximately 600 C, promoted by the effects of solute drag and precipitation hardening. Macroscopic thermomechanical hardening trends are correlated with microstructural characteristics through the use of transmission electron microscopy. These observations are compared and contrasted with isothermal conditions. Thermomechanical behavior unique to the isothermal database is identified and discussed. The microstructural characteristics were shown to be dominated by effects associated with the highest temperature of the thermomechanical cycle. Results indicate that the deformation behavior of Hastelloy X is thermomechanically path dependent. In addition, guidance is given pertaining to deformation modeling in the context of macroscopic unified theory. An internal state variable is formulated to qualitatively reflect the isotropic hardening trends identified in the TMD experiments.

A systematic review and meta-analysis of the relative efficacy and safety of treatment regimens for HIV-associated cerebral toxoplasmosis: is trimethoprim-sulfamethoxazole a real option?

PubMed

Hernandez, A V; Thota, P; Pellegrino, D; Pasupuleti, V; Benites-Zapata, V A; Deshpande, A; Penalva de Oliveira, A C; Vidal, J E

2017-02-01

The objective of this study was to perform a systematic review and meta-analysis of the literature to evaluate the efficacy and safety of therapies for cerebral toxoplasmosis in HIV-infected adults. The pyrimethamine plus sulfadiazine (P-S) combination is considered the mainstay therapy for cerebral toxoplasmosis and pyrimethamine plus clindamycin (P-C) is the most common alternative treatment. Although trimethoprim-sulfamethoxazole (TMP-SMX) has potential advantages, its use is infrequent. We searched PubMed and four other databases to identify randomized controlled trials (RCTs) and cohort studies. Two independent reviewers searched the databases, identified studies and extracted data. Risk ratios (RRs) were pooled across studies using random-effects models. Nine studies were included (five RCTs, three retrospective cohort studies and one prospective cohort study). In comparison to P-S, treatment with P-C or TMP-SMX was associated with similar rates of partial or complete clinical response [P-C: RR 0.87; 95% confidence interval (CI) 0.70-1.08; TMP-SMX: RR 0.97; 95% CI 0.78-1.21], radiological response (P-C: RR 0.92; 95% CI 0.82-1.03), skin rash (P-C: RR 0.81; 95% CI 0.56-1.17; TMP-SMX: RR 0.17; 95% CI 0.02-1.29), gastrointestinal impairment (P-C: RR 5.16; 95% CI 0.66-40.11), and drug discontinuation because of adverse events (P-C: RR 0.32; 95% CI 0.07-1.47). Liver impairment was more frequent with P-S than P-C (P-C vs. P-S: RR 0.48; 95% CI 0.24-0.97). The current evidence fails to identify a superior regimen in terms of relative efficacy or safety for the treatment of HIV-associated cerebral toxoplasmosis. Use of TMP-SMX as preferred treatment may be consistent with the available evidence and other real-world considerations. Larger comparative studies are needed. © 2016 British HIV Association.

A mechanism for leader stepping

NASA Astrophysics Data System (ADS)

Ebert, U.; Carlson, B. E.; Koehn, C.

2013-12-01

The stepping of negative leaders is well observed, but not well understood. A major problem consists of the fact that the streamer corona is typically invisible within a thunderstorm, but determines the evolution of a leader. Motivated by recent observations of streamer and leader formation in the laboratory by T.M.P. Briels, S. Nijdam, P. Kochkin, A.P.J. van Deursen et al., by recent simulations of these processes by J. Teunissen, A. Sun et al., and by our theoretical understanding of the process, we suggest how laboratory phenomena can be extrapolated to lightning leaders to explain the stepping mechanism.

Unraveling the Effect of Thermomechanical Treatment on the Dissolution of Delta Ferrite in Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Rezayat, Mohammad; Mirzadeh, Hamed; Namdar, Masih; Parsa, Mohammad Habibi

2016-02-01

Considering the detrimental effects of delta ferrite stringers in austenitic stainless steels and the industrial considerations regarding energy consumption, investigating, and optimizing the kinetics of delta ferrite removal is of vital importance. In the current study, a model alloy prone to the formation of austenite/delta ferrite dual phase microstructure was subjected to thermomechanical treatment using the wedge rolling test aiming to dissolve delta ferrite. The effect of introducing lattice defects and occurrence of dynamic recrystallization (DRX) were investigated. It was revealed that pipe diffusion is responsible for delta ferrite removal during thermomechanical process, whereas when the DRX is dominant, the kinetics of delta ferrite dissolution tends toward that of the static homogenization treatment for delta ferrite removal that is based on the lattice diffusion of Cr and Ni in austenite. It was concluded that the optimum condition for dissolution of delta ferrite can be defined by the highest rolling temperature and strain in which DRX is not pronounced.

Development of antimicrobial active packaging materials based on gluten proteins.

PubMed

Gómez-Heincke, Diana; Martínez, Inmaculada; Partal, Pedro; Guerrero, Antonio; Gallegos, Críspulo

2016-08-01

The incorporation of natural biocide agents into protein-based bioplastics, a source of biodegradable polymeric materials, manufactured by a thermo-mechanical method is a way to contribute to a sustainable food packaging industry. This study assesses the antimicrobial activity of 10 different biocides incorporated into wheat gluten-based bioplastics. The effect that formulation, processing, and further thermal treatments exert on the thermo-mechanical properties, water absorption characteristics and rheological behaviour of these materials is also studied. Bioplastics containing six of the 10 examined bioactive agents have demonstrated suitable antimicrobial activity at 37 °C after their incorporation into the bioplastic. Moreover, the essential oils are able to create an antimicrobial atmosphere within a Petri dish. Depending on the selected biocide, its addition may alter the bioplastics protein network in a different extent, which leads to materials exhibiting less water uptake and different rheological and thermo-mechanical behaviours. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Analysis of the independent power of age-related, anthropometric and mechanical factors as determinants of the structure of radius and tibia in normal adults. A pQCT study.

PubMed

Reina, P; Cointry, G R; Nocciolino, L; Feldman, S; Ferretti, J L; Rittweger, J; Capozza, R F

2015-03-01

To compare the independent influence of mechanical and non-mechanical factors on bone features, multiple regression analyses were performed between pQCT indicators of radius and tibia bone mass, mineralization, design and strength as determined variables, and age or time since menopause (TMP), body mass, bone length and regional muscles' areas as selected determinant factors, in Caucasian, physically active, untrained healthy men and pre- and post-menopausal women. In men and pre-menopausal women, the strongest influences were exerted by muscle area on radial features and by both muscle area and bone length on the tibia. Only for women, was body mass a significant factor for tibia traits. In men and pre-menopausal women, mass/design/strength indicators depended more strongly on the selected determinants than the cortical vBMD did (p<0.01-0.001 vs n.s.), regardless of age. However, TMP was an additional factor for both bones (p<0.01-0.001). The selected mechanical factors (muscle size, bone lengths) were more relevant than age/TMP or body weight to the development of allometrically-related bone properties (mass/design/strength), yet not to bone tissue 'quality' (cortical vBMD), suggesting a determinant, rather than determined role for cortical stiffness. While the mechanical impacts of muscles and bone levers on bone structure were comparable in men and pre-menopausal women, TMP exerted a stronger impact than allometric or mechanical factors on bone properties, including cortical vBMD.

Antimicrobial susceptibility patterns of Shigella isolates in Foodborne Diseases Active Surveillance Network (FoodNet) sites, 2000-2010.

PubMed

Shiferaw, Beletshachew; Solghan, Suzanne; Palmer, Amanda; Joyce, Kevin; Barzilay, Ezra J; Krueger, Amy; Cieslak, Paul

2012-06-01

Treatment of shigellosis with appropriate antimicrobial agents shortens duration of illness and bacterial shedding, but resistance to commonly used agents is increasing. We describe resistance patterns among Shigella isolates in the United States with use of linked data from the Foodborne Diseases Active Surveillance Network (FoodNet) and National Antimicrobial Resistance Monitoring System (NARMS). FoodNet sites send every 20th Shigella isolate to the NARMS laboratory for susceptibility testing. During 2000-2010, the NARMS laboratory tested 1376 Shigella isolates from FoodNet sites. Of 1118 isolates (81%) linked to FoodNet, 826 (74%) were resistant to ampicillin, 649 (58%) to streptomycin, 402 (36%) to trimethoprim-sulfamethoxazole (TMP-SMX), 355 (32%) to sulfamethoxazole-sulfisoxazole, 312 (28%) to tetracycline, 19 (2%) to nalidixic acid, and 6 (0.5%) to ciprofloxacin. The proportion of Shigella isolates with resistance to TMP-SMX was 40% among white persons, 58% among Hispanic persons, and 75% among persons with a history of international travel. Resistance to at least TMP-SMX and ampicillin was present in 25% of isolate, and 5% were resistant to ampicillin, TMP-SMX, and chloramphenicol. Overall, 5% of isolates showed multidrug resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole-sulfisoxazole, and tetracycline, including 49 Shigella flexneri (33%) and 3 Shigella sonnei (0.3%) isolates. Male individuals were more likely than female individuals to be infected with a multidrug-resistant strain (7% versus 3%; P < .01). Antimicrobial resistance differed by race, ethnicity, age, travel, and species. Resistance to commonly used antibiotics is high; therefore, it is important to look at the susceptibility pattern before starting treatment.

Treatment of chancroid. A comparison of sulphamethoxazole and trimethoprim-sulphamethoxazole.

PubMed Central

Fast, M V; Nsanze, H; Plummer, F A; D'Costa, L J; MacLean, I W; Ronald, A R

1983-01-01

Since sulphonamides are no longer predictably effective in the treatment of chancroid the combination of trimethoprim-sulphamethoxazole (TMP-SMX) was evaluated to identify other effective regimens. One hundred and nine patients with genital ulcers (75 men and 34 women) seen at the Special Treatment Clinic in Nairobi, Kenya, were randomly assigned to treatment with a seven day course of either sulphamethoxazole 1000 mg twice daily or trimethoprim (160 mg)-sulphamethoxazole (800 mg) (TMP-SMX) twice daily. Haemophilus ducreyi was isolated from the ulcer in 57 patients (33 men and 24 women). 16 patients were subsequently diagnosed serologically as having syphilis. No aetiological diagnosis was made in 40 patients. Treatment with sulphamethoxazole failed in five of 21 (24%) culture positive patients who were available for evaluation after seven days, whereas all 19 of such patients who were treated with TMP-SMX responded to treatment. Of the 21 isolates available for susceptibility testing, all were susceptible to trimethoprim alone (MIC less than 0.5 mg/l) and three were resistant to sulphonamides, all three containing a 4.9 megadalton (Mdal) plasmid. Two of the three patients from whom these isolates had been obtained were treated with sulphamethoxazole and both were clinical and bacteriological failures. Five of six patients with sulphonamide-susceptible H ducreyi responded to treatment with sulphamethoxazole. Failure of sulphonamides to eradicate H ducreyi in some patients with chancroid is associated with the presence of a sulphonamide resistant plasmid. In regions where this plasmid is present in H ducreyi TMP-SMX is the preferred treatment for chancroid. PMID:6351957

Structural comparison of chromosomal and exogenous dihydrofolate reductase from Staphylococcus aureus in complex with the potent inhibitor trimethoprim

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

Heaslet, Holly; Harris, Melissa; Fahnoe, Kelly

2010-09-02

Dihydrofolate reductase (DHFR) is the enzyme responsible for the NADPH-dependent reduction of 5,6-dihydrofolate to 5,6,7,8-tetrahydrofolate, an essential cofactor in the synthesis of purines, thymidylate, methionine, and other key metabolites. Because of its importance in multiple cellular functions, DHFR has been the subject of much research targeting the enzyme with anticancer, antibacterial, and antimicrobial agents. Clinically used compounds targeting DHFR include methotrexate for the treatment of cancer and diaminopyrimidines (DAPs) such as trimethoprim (TMP) for the treatment of bacterial infections. DAP inhibitors of DHFR have been used clinically for >30 years and resistance to these agents has become widespread. Methicillin-resistant Staphylococcusmore » aureus (MRSA), the causative agent of many serious nosocomial and community acquired infections, and other gram-positive organisms can show resistance to DAPs through mutation of the chromosomal gene or acquisition of an alternative DHFR termed 'S1 DHFR.' To develop new therapies for health threats such as MRSA, it is important to understand the molecular basis of DAP resistance. Here, we report the crystal structure of the wild-type chromosomal DHFR from S. aureus in complex with NADPH and TMP. We have also solved the structure of the exogenous, TMP resistant S1 DHFR, apo and in complex with TMP. The structural and thermodynamic data point to important molecular differences between the two enzymes that lead to dramatically reduced affinity of DAPs to S1 DHFR. These differences in enzyme binding affinity translate into reduced antibacterial activity against strains of S. aureus that express S1 DHFR.« less

Experimental investigation of cyclic thermomechanical deformation in torsion

NASA Technical Reports Server (NTRS)

Ellis, John R.; Castelli, Michael G.; Bakis, Charles E.

1992-01-01

An investigation of thermomechanical testing and deformation behavior of tubular specimens under torsional loading is described. Experimental issues concerning test accuracy and control specific to thermomechanical loadings under a torsional regime are discussed. A series of shear strain-controlled tests involving the nickel-base superalloy Hastelloy X were performed with various temperature excursions and compared to similar thermomechanical uniaxial tests. The concept and use of second invariants of the deviatoric stress and strain tensors as a means of comparing uniaxial and torsional specimens is also briefly presented and discussed in light of previous thermomechanical tests conducted under uniaxial conditions.

A Transversely Isotropic Thermo-mechanical Framework for Oil Shale

NASA Astrophysics Data System (ADS)

Semnani, S. J.; White, J. A.; Borja, R. I.

2014-12-01

The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers, 2002.

First-Line Antimicrobial Resistance Patterns of Escherichia coli in Children With Urinary Tract Infection in Emergency Department and Primary Care Clinics.

PubMed

Ahmed, M Nadeem; Vannoy, Debby; Frederick, Ann; Chang, Sandy; Lawler, Elisabeth

2016-01-01

To identify risk factors for antibiotic resistance to Escherichia coli (E. coli) in children with urinary tract infections (UTIs) in emergency room and primary care clinics. This is a cross-sectional study of children 0 to 18 years of age reported to have E coli-positive UTIs whose medical and laboratory records were systematically reviewed. Compared with girls, boys were 2.29 times (confidence interval [CI] = 1.30-4.02) more likely to have E coli isolates resistant to ampicillin and 2 times more likely (CI = 1.13-3.62) to have isolates resistant to trimethoprim-sulfamethoxazole (TMP/SMX). Patients with genitourinary abnormalities were 1.57 times more likely to be resistant to ampicillin (CI = 1.03-2.41) and 1.86 times to TMP/SMX (CI = 1.18-2.94). Higher rates of ampicillin and TMP/SMX resistant urinary E coli isolates were observed among boys and children with a history of genitourinary abnormality. Age and recent antibiotic prescription are also potential risk factors for resistance. © The Author(s) 2015.

Interaction of Tl +3 with mononucleotides: metal ion binding and sugar conformation

NASA Astrophysics Data System (ADS)

Nafisi, Sh.; Mohajerani, N.; Hadjiakhoondi, A.; Monajemi, M.; Garib, F.

2001-05-01

The interaction of Tl 3+ with sodium salts of adenosine-5'-monophosphate (5'-AMP), guanosine-5'-monophosphate (5'-GMP), cytidine-5'-monophosphate (5'-CMP), thymidine 5'-monophosphate (5'-dTMP) in ratios 1 and 2 have been studied in neutral pH. The solid complexes were isolated and characterized by Fourier transform infrared (FTIR) and 1H NMR spectroscopy. In the Tl 2(AMP) 3, Tl 3+ binds directly to N-7 and indirectly to the N-1 position of the pyrimidine ring and phosphate group with sugar moiety in C2'-endoanti. The crystalline salt of Tl 2(GMP) 3 show direct Tl-N-7 and Tl-PO 3(inner-sphere) binding. The conformation of ribose moiety in Tl 2(GMP) 3 is C3'-endoanti. In the Tl 2(CMP) 3, Tl 3+ bind directly to N-3 and PO32- (inner-sphere). The conformation of ribose moiety in Tl 2(CMP) 3 is C2'-endoanti. In the Tl 2(dTMP) 3, Tl 3+ bind indirectly to carbonyl group. The sugar moiety in Tl 2(dTMP) 3 is C3'-endoanti.

High-throughput prediction of tablet weight and trimethoprim content of compound sulfamethoxazole tablets for controlling the uniformity of dosage units by NIR.

PubMed

Dong, Yanhong; Li, Juan; Zhong, Xiaoxiao; Cao, Liya; Luo, Yang; Fan, Qi

2016-04-15

This paper establishes a novel method to simultaneously predict the tablet weight (TW) and trimethoprim (TMP) content of compound sulfamethoxazole tablets (SMZCO) by near infrared (NIR) spectroscopy with partial least squares (PLS) regression for controlling the uniformity of dosage units (UODU). The NIR spectra for 257 samples were measured using the optimized parameter values and pretreated using the optimized chemometric techniques. After the outliers were ignored, two PLS models for predicting TW and TMP content were respectively established by using the selected spectral sub-ranges and the reference values. The TW model reaches the correlation coefficient of calibration (R(c)) 0.9543 and the TMP content model has the R(c) 0.9205. The experimental results indicate that this strategy expands the NIR application in controlling UODU, especially in the high-throughput and rapid analysis of TWs and contents of the compound pharmaceutical tablets, and may be an important complement to the common NIR on-line analytical method for pharmaceutical tablets. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermodynamic impact of abasic sites on simulated translesion DNA synthesis.

PubMed

Malina, Jaroslav; Brabec, Viktor

2014-06-16

Loss of a base in DNA and the creation of an abasic (apurinic/apyrimidinic, AP) site is a frequent lesion that may occur spontaneously, or as a consequence of the action of DNA-damaging agents. The AP lesion is mutagenic or lethal if not repaired. We report a systematic thermodynamic investigation by differential scanning calorimetry on the evolution, during primer extension, of a model AP site in chemically simulated DNA translesion synthesis. Incorporation of dAMP (deoxyadenosine monophosphate), as well as dTMP (deoxythymidine monophosphate), opposite an AP site is enthalpically unfavorable, although incorporation of dTMP is more enthalpically unfavorable than that of dAMP. This finding is in a good agreement with experimental data showing that AP sites block various DNA polymerases of eukaryotic and prokaryotic origin and that, if bypassed, dAMP is preferentially inserted, whereas insertion of dTMP is less likely. The results emphasize the importance of thermodynamic contributions to the insertion of nucleotides opposite an AP site by DNA polymerases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Finite Element Simulation of Temperature and Strain Distribution during Friction Stir Welding of AA2024 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Jain, Rahul; Pal, Surjya Kanta; Singh, Shiv Brat

2017-02-01

Friction Stir Welding (FSW) is a solid state joining process and is handy for welding aluminum alloys. Finite Element Method (FEM) is an important tool to predict state variables of the process but numerical simulation of FSW is highly complex due to non-linear contact interactions between tool and work piece and interdependency of displacement and temperature. In the present work, a three dimensional coupled thermo-mechanical method based on Lagrangian implicit method is proposed to study the thermal history, strain distribution and thermo-mechanical process in butt welding of Aluminum alloy 2024 using DEFORM-3D software. Workpiece is defined as rigid-visco plastic material and sticking condition between tool and work piece is defined. Adaptive re-meshing is used to tackle high mesh distortion. Effect of tool rotational and welding speed on plastic strain is studied and insight is given on asymmetric nature of FSW process. Temperature distribution on the workpiece and tool is predicted and maximum temperature is found in workpiece top surface.

Characterization of the microstructure of Nb-1wt.%Zr-0.1wt.%C tubes as affected by thermomechanical processing

NASA Technical Reports Server (NTRS)

Uz, Mehmet; Titran, Robert H.

1993-01-01

Microstructure of Nb-1Zr-0.1C tubes were characterized as affected by extrusion temperature of the tube shell and its thermomechanical processing to tubing. Two tube shells of about 40-mm outside diameter (OD) and 25-mm inside diameter (ID) were extruded 8:1 from a vacuum arc-melted ingot at 1900 and 1550 K. Two different OD tubes of approximately 0.36-mm wall thickness were fabricated from each tube shell by a series of 26 cold drawing operations with two in process anneals. The microstructure of tube shells and the tubing before and after a 2-step heat treatment were characterized. Residue extracted chemically from each sample was also analyzed to identify the precipitates. The results concerning the effect of the initial extrusion temperature and subsequent processing on the microstructure of the tubes are presented together with a review of results from similar work on Nb-1Zr-0.1C sheet stock.

A trace-driven analysis of name and attribute caching in a distributed system

NASA Technical Reports Server (NTRS)

Shirriff, Ken W.; Ousterhout, John K.

1992-01-01

This paper presents the results of simulating file name and attribute caching on client machines in a distributed file system. The simulation used trace data gathered on a network of about 40 workstations. Caching was found to be advantageous: a cache on each client containing just 10 directories had a 91 percent hit rate on name look ups. Entry-based name caches (holding individual directory entries) had poorer performance for several reasons, resulting in a maximum hit rate of about 83 percent. File attribute caching obtained a 90 percent hit rate with a cache on each machine of the attributes for 30 files. The simulations show that maintaining cache consistency between machines is not a significant problem; only 1 in 400 name component look ups required invalidation of a remotely cached entry. Process migration to remote machines had little effect on caching. Caching was less successful in heavily shared and modified directories such as /tmp, but there weren't enough references to /tmp overall to affect the results significantly. We estimate that adding name and attribute caching to the Sprite operating system could reduce server load by 36 percent and the number of network packets by 30 percent.

3D Thermomechanical Modeling of Rifted Margins with Coupled Surface Processes: the North West Shelf, Australia

NASA Astrophysics Data System (ADS)

Moresi, L. N.; Beucher, R.; Morón, S.; Rey, P. F.; Salles, T.; Brocard, G. Y.; Farrington, R.; Giordani, J.; Mansour, J.

2017-12-01

Thermo-mechanical numerical models and analogue experiments with a layered lithosphere have emphasised the role played by the composition and thermal state of the lithosphere on the style of extension. The variation in rheological properties and the coupling between lithospheric layers promote depth-dependent extension with the potential for complex rift evolution over space and time. Local changes in the stress field due to loading / unloading of the lithosphere can perturb the syn and post-rift stability of the margins. We investigate how erosion of the margins and sedimentation within the basins integrate with the thermo-mechanical processes involved in the structural and stratigraphic evolution of the North West Shelf (NWS), one of the most productive and prospective hydrocarbon provinces in Australia. The complex structural characteristics of the NWS include large-scale extensional detachments, difference between amounts of crustal and lithospheric extension and prolonged episodes of thermal sagging after rifting episodes. It has been proposed that the succession of different extensional styles mechanisms (Cambrian detachment faulting, broadly distributed Permo-Carboniferous extension and Late Triassic to Early Cretaceous localised rift development) is best described in terms of variation in deformation response of a lithosphere that has strengthened from one extensional episode to the next. However, previous models invoking large-scale detachments fail to explain changes in extensional styles and overestimate the structural importance of relatively local detachments. Here, we hypothesize that an initially weak lithosphere would distribute deformation by ductile flow within the lower crust and that the interaction between crustal flow, thermal-evolution and sediment loading/unloading could explain some of the structural complexities recorded by the NWS. We run a series of fully coupled 3D thermo-mechanical numerical experiments that include realistic thermal and mechanical properties, as well as surface processes (erosion, sediments transport and sedimentation). This modeling approach aims to provide insights into the thermal and structural history of the NWS, and a better understanding of the complex interactions between tectonics and surface processes at rifted margins.

Effect of Plastic Hot Deformation on the Hardness and Continuous Cooling Transformations of 22MnB5 Microalloyed Boron Steel

NASA Astrophysics Data System (ADS)

Barcellona, A.; Palmeri, D.

2009-05-01

The strains, transformation temperatures, microstructure, and microhardness of a microalloyed boron and aluminum precoated steel, which has been isothermally deformed under uniaxial tensile tests, have been investigated at temperatures between 873 and 1223 K, using a fixed strain rate value of 0.08 s-1. The effect of each factor, such as temperature and strain value, has been later valued considering the shift generated on the continuous cooling transformation (CCT) diagram. The experimental results consist of the starting temperatures that occur for each transformation, the microhardness values, and the obtained microstructure at the end of each thermomechanical treatment. All the thermomechanical treatments were performed using the thermomechanical simulator Gleeble 1500. The results showed that increasing hot prestrain (HPS) values generate, at the same cooling rate, lower hardness values; this means that the increasing of HPS generates a shift of the CCT diagram toward a lower starting time for each transformation. Therefore, high values of hot deformations during the hot stamping process require a strict control of the cooling process in order to ensure cooling rate values that allow maintaining good mechanical component characteristics. This phenomenon is amplified when the prestrain occurs at lower temperatures, and thus, it is very sensitive to the temperature level.

Texture evolution during thermomechanical processing in rare earth free magnesium alloys

NASA Astrophysics Data System (ADS)

Miller, Victoria Mayne

The use of wrought magnesium alloys is highly desirable for a wide range of applications where low component weight is desirable due to the high specific strength and stiffness the alloys can achieve. However, the implementation of wrought magnesium has been hindered by the limited room temperature formability which typically results from deformation processing. This work identifies opportunities for texture modification during thermomechanical processing of conventional (rare earth free) magnesium alloys via a combination of experimental investigation and polycrystal plasticity simulations. During deformation, it is observed that a homogeneous distribution of coarse intermetallic particles efficiently weakens deformation texture at all strain levels, while a highly inhomogeneous particle distribution is only effective at high strains. The particle deformation effects are complemented by the addition of alkaline earth solute, which modifies the relative deformation mode activity. During recrystallization, grains with basal orientations recrystallize more readily than off-basal grains, despite similar levels of internal misorientation. Dislocation substructure investigations revealed that this is a result of enhanced nucleation in the basal grains due to the dominance of prismatic slip. This dissertation identifies avenues to enhance the potential formability of magnesium alloys during thermomechanical processing by minimizing the evolved texture strength. The following are the identified key aspects of microstructural control: -Maintaining a fine grain size, likely via Zener pinning, to favorably modify deformation mode activity and homogenize deformation. -Developing a coarse, homogeneously distributed population of coarse intermetallic particles to promote a diffuse deformation texture. -Minimizing the activity of prismatic slip to retard the recrystallization of grains with basal orientations, allowing the development of a more diffuse recrystallization texture.

Litigation Technical Support and Services, Rocky Mountain Arsenal. Biota Remedial Investigation (Version 3.2). Volume 2

DTIC Science & Technology

1989-05-01

Trimethyl phosphate (TMP), a known mutagen, is a minor contaminant in the processing of azodrin (EPA, 1985h). Tke EPA (1985h) states that azodrin is...day (Sax, 1984)) for cholinesterase inhibition based on a chronic rat feeding study that showed minor depressive trends in AChE at dose levels of 0.09...3 (Giesy at al., 1979). At 10 ppb cadmium, growth reduction was observed in a fern (Salmina natans) and duckweed ( Lemna maldixiana) (Hutchinson and

Rheological behavior of the crust and mantle in subduction zones in the time-scale range from earthquake (minute) to mln years inferred from thermomechanical model and geodetic observations

NASA Astrophysics Data System (ADS)

Sobolev, Stephan; Muldashev, Iskander

2016-04-01

The key achievement of the geodynamic modelling community greatly contributed by the work of Evgenii Burov and his students is application of "realistic" mineral-physics based non-linear rheological models to simulate deformation processes in crust and mantle. Subduction being a type example of such process is an essentially multi-scale phenomenon with the time-scales spanning from geological to earthquake scale with the seismic cycle in-between. In this study we test the possibility to simulate the entire subduction process from rupture (1 min) to geological time (Mln yr) with the single cross-scale thermomechanical model that employs elasticity, mineral-physics constrained non-linear transient viscous rheology and rate-and-state friction plasticity. First we generate a thermo-mechanical model of subduction zone at geological time-scale including a narrow subduction channel with "wet-quartz" visco-elasto-plastic rheology and low static friction. We next introduce in the same model classic rate-and state friction law in subduction channel, leading to stick-slip instability. This model generates spontaneous earthquake sequence. In order to follow in details deformation process during the entire seismic cycle and multiple seismic cycles we use adaptive time-step algorithm changing step from 40 sec during the earthquake to minute-5 year during postseismic and interseismic processes. We observe many interesting deformation patterns and demonstrate that contrary to the conventional ideas, this model predicts that postseismic deformation is controlled by visco-elastic relaxation in the mantle wedge already since hour to day after the great (M>9) earthquakes. We demonstrate that our results are consistent with the postseismic surface displacement after the Great Tohoku Earthquake for the day-to-4year time range.

Membrane processes

NASA Astrophysics Data System (ADS)

Staszak, Katarzyna

2017-11-01

The membrane processes have played important role in the industrial separation process. These technologies can be found in all industrial areas such as food, beverages, metallurgy, pulp and paper, textile, pharmaceutical, automotive, biotechnology and chemical industry, as well as in water treatment for domestic and industrial application. Although these processes are known since twentieth century, there are still many studies that focus on the testing of new membranes' materials and determining of conditions for optimal selectivity, i. e. the optimum transmembrane pressure (TMP) or permeate flux to minimize fouling. Moreover the researchers proposed some calculation methods to predict the membrane processes properties. In this article, the laboratory scale experiments of membrane separation techniques, as well their validation by calculation methods are presented. Because membrane is the "heart" of the process, experimental and computational methods for its characterization are also described.

Changes in bacterial resistance patterns in children with urinary tract infections on antimicrobial prophylaxis at University Hospital in Split

PubMed Central

Ilić, Tanja; Gračan, Sanda; Arapović, Adela; Čapkun, Vesna; Šubat-Dežulović, Mirna; Saraga, Marijan

2011-01-01

Summary Background We assessed prevalence and resistance of uropathogens on antimicrobial agents (AA) from urine cultures (UC) in children hospitalized with urinary tract infections (UTI) at University Hospital in Split. Material/Methods During the 7-year period, children hospitalized only once with UTI alone were compared to those repeatedly hospitalized, and who received long-term antimicrobial prophylaxis (LTAP), as well as those with associated anomalies of the urinary system (US). Results E. coli was the most frequent isolate (67.7%) with resistance to ampicillin by 69.5%, amoxicillin/clavulonic acid by 3.5%, cephalexin by 6.6%, trimethoprim/sulfamethoxazole (TMP-SMX) by 27.5%, and nitrofurantoin by 0.4%. For other uropathogens, AA resistance rates were the following: 64.3%, 5.8%, 10.5%, 21.3%, and 7.9%. The high or increasing resistance to TMP-SMX is characterized by all uropathogens. Patients with anomalies of US showed a lower prevalence of E. coli and Enterococcus sp., but a higher prevalence of Pseudomonas sp., ESBL-producing E. coli and Klebsiella sp. than those without US anomalies. Repeatedly hospitalized patients showed a lower prevalence of E. coli, but a higher prevalence of Pseudomonas sp. and Klebsiella sp. than patients hospitalized only once. Both groups displayed significantly less resistance of Enterococcus sp. In patients receiving LTAP before hospitalization, E. coli was significantly more resistant to ampicillin, amoxicillin/clavulonic acid and TMP/SMX than in those without LTAP. Conclusions Based on our results, we recommend excluding ampicillin altogether, and reconsideration of further use of TMP-SMX, as well as use of nitrofurantoin, cephalexin and amoxicillin/clavulonic acid for LTAP in our region. PMID:21709628

Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages

PubMed Central

Waheed, Zarinah; van Mil, Harald G. J.; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W.

2015-01-01

The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park. PMID:26719987

Bonding performance of experimental bioactive/biomimetic self-etch adhesives doped with calcium-phosphate fillers and biomimetic analogs of phosphoproteins.

PubMed

Abuna, Gabriel; Feitosa, Victor P; Correr, Americo Bortolazzo; Cama, Giuseppe; Giannini, Marcelo; Sinhoreti, Mario A; Pashley, David H; Sauro, Salvatore

2016-09-01

This study examined the bonding performance and dentin remineralization potential of an experimental adhesive containing calcium-phosphate (Ca/P) micro-fillers, and self-etching primers doped with phosphoprotein biomimetic analogs (polyacrylic acid-(PAA) and/or sodium trimetaphosphate-(TMP)). Experimental self-etching primers doped with biomimetic analogs (PAA and/or TMP), and an adhesive containing Ca(2+), PO4(-3)-releasing micro-fillers (Ca/P) were formulated. Sound human dentin specimens were bonded and cut into sticks after aging (24h or 6 months) under simulated pulpal pressure (20cm H2O), and tested for microtensile bond strength (μTBS). Results were analyzed using two-way ANOVA and Tukey's test (p<0.05). Interfacial silver nanoleakage was assessed using SEM. Remineralization of EDTA-demineralized dentin was assessed through FTIR and TEM ultrastructural analysis. Application of the Ca/P-doped adhesive with or without dentin pre-treatments with the primer containing both biomimetic analogs (PAA and TMP) promoted stable μTBS over 6 months. Conversely, μTBS of the control primer and filler-free adhesive significantly decreased after 6 months. Nanoleakage decreased within the resin-dentin interfaces created using the Ca/P-doped adhesives. EDTA-demineralized dentin specimens treated the Ca/P-doped adhesive and the primer containing PAA and TMP showed phosphate uptake (FTIR analysis), as well as deposition of needle-like crystallites at intrafibrillar level (TEM analysis). The use of Ca/P-doped self-etching adhesives applied in combination with analogs of phosphoproteins provides durable resin-dentin bonds. This approach may represent a suitable bonding strategy for remineralization of intrafibrillar dentin collagen within the resin-dentin interface. Copyright © 2016 Elsevier Ltd. All rights reserved.

Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms.

PubMed

Rivero Berti, Ignacio; Dell' Arciprete, María Laura; Dittler, María Laura; Miñan, Alejandro; Fernández Lorenzo de Mele, Mónica; Gonzalez, Mónica

2016-06-01

The delivery capacity and mechanical stability of calcium phosphate (CaP) coated 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) liposomes free and adsorbed on bacterial surface was investigated introducing either acridine orange (AO) or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin (TMP) in the aqueous core of the liposomes. The obtained nanomaterials were thoroughly characterized by electron and optical microscopy and by fluorescence techniques. Distribution of the AO and TMP molecules between the aqueous liposomes core and the outer solution was demonstrated by the band shifts and broadening of the excitation-emission matrices and the modified Stern-Volmer model for fluorescence quenching. In aqueous suspensions, c.a. 40% of AO was released to the outer solution while only a small percentage of TMP was observed to reach the outer liposome surface. The nanoliposomes adhesion capacity and the leaking of fluorophore molecules to Staphylococcus aureus (S. aureus) biofilms were further evaluated. A close interaction between liposomes and S. aureus biofilm was evidenced by TEM and SEM imaging. Epifluorescence experiments demonstrated that CaP-coated liposomes have good biofilm staining capability after two hours incubation of the biofilms with the liposomes, thus supporting an important release of the fluorophores when in contact with the biofilm. Altogether, the obtained results strongly suggest that CaP-coated liposomes are capable of activating drug release when in presence of S. aureus biofilms and smears. The studies herein presented, indicate that CaP-coated liposomes are potential vehicles for the selective delivery of drugs to S. aureus biofilms, as is the case of the singlet oxygen photosensitizer TMP, a well known photodynamic antibacterial agent. Copyright © 2016 Elsevier B.V. All rights reserved.

Systematic review and meta-analysis of secondary prophylaxis for prevention of HIV-related toxoplasmic encephalitis relapse using trimethoprim-sulfamethoxazole.

PubMed

Connolly, Mark P; Haitsma, Gertruud; Hernández, Adrián V; Vidal, José E

2017-09-01

A recent systematic literature and meta-analysis reported relative efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of toxoplasmic encephalitis (TE) in HIV-infected adults. Here, we estimated relapse rates during secondary prophylaxis with TMP-SMX, and further explored differences in relapse rates prior to introduction of highly active antiretroviral therapy (HAART) and the widespread adoption of HAART. A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials yielded 707 studies whereby 663 were excluded after abstract screening, and 38 were excluded after full review leaving 6 studies for extraction. We performed double data extraction with a third-party adjudicator. Study designs varied with only one randomized study, four prospective cohorts and one retrospective cohort. Relapse rates were transformed using the Freeman-Tukey method and pooled using both fixed-effect and random-effects meta-analysis models. The TMP-SMX relapse rate was 16.4% (95% CI = 6.2% to 30.3%) based on random-effects models. When the disaggregated pre-HAART studies (n = 4) were included, the relapse rate was 14.9% (random effects; 95% CI = 3.7% to 31.9%). Analysis of two post-HAART studies indicated a relapse rate of 19.2% (random effects; 95% CI = 2.8% to 45.6%). Comparing the relapse rates between pre- and post-HAART studies were contrary to what might be expected based on known benefits of HAART therapy in this population. Nevertheless, cautious interpretation is necessary considering the heterogeneity of the included studies and a limited number of subjects receiving TMP-SMX reported in the post-HAART era.

A Case of Pneumonia Caused by Pneumocystis jirovecii Resistant to Trimethoprim-Sulfamethoxazole.

PubMed

Lee, Sang Min; Cho, Yong Kyun; Sung, Yon Mi; Chung, Dong Hae; Jeong, Sung Hwan; Park, Jeong-Woong; Lee, Sang Pyo

2015-06-01

A 50-year-old male visited the outpatient clinic and complained of fever, poor oral intake, and weight loss. A chest X-ray demonstrated streaky and fibrotic lesions in both lungs, and chest CT revealed multifocal peribronchial patchy ground-glass opacities with septated cystic lesions in both lungs. Cell counts in the bronchoalveolar lavage fluid revealed lymphocyte-dominant leukocytosis, and further analysis of lymphocyte subsets showed a predominance of cytotoxic T cells and few T helper cells. Video-assisted wedge resection of the left upper lobe was performed, and the histologic examination was indicative of a Pneumocystis jirovecii infection. Trimethoprim-sulfamethoxazole (TMP-SMX) was orally administered for 3 weeks; however, the patient complained of cough, and the pneumonia was aggravated in the follow-up chest X-ray and chest CT. Molecular studies demonstrated mutations at codons 55 and 57 of the dihydropteroate synthase (DHPS) gene, which is associated with the resistance to TMP-SMX. Clindamycin-primaquine was subsequently administered for 3 weeks replacing the TMP-SMX. A follow-up chest X-ray showed that the pneumonia was resolving, and the cough was also alleviated. A positive result of HIV immunoassay and elevated titer of HCV RNA indicated HIV infection as an underlying condition. This case highlights the importance of careful monitoring of patients with P. jirovecii pneumonia (PCP) during the course of treatment, and the molecular study of DHPS mutations. Additionally, altering the anti-PCP drug utilized as treatment must be considered when infection with drug-resistant P. jirovecii is suspected. To the best of our knowledge, this is the first case of TMP-SMX-resistant PCP described in Korea.

Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages.

PubMed

Waheed, Zarinah; van Mil, Harald G J; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W

2015-01-01

The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park.

Thermomechanical deformation testing and modeling in the presence of metallurgical instabilities. M.S. Thesis - Akron Univ. Final Report

NASA Technical Reports Server (NTRS)

Castelli, Michael G.

1990-01-01

A number of viscoplastic constitutive models were developed to describe deformation behavior under complex combinations of thermal and mechanical loading. Questions remain, however, regarding the validity of procedures used to characterize these models for specific structural alloys. One area of concern is that the majority of experimental data available for this purpose are determined under isothermal conditions. This experimental study is aimed at determining whether viscoplastic constitutive theories characterized using an isothermal data base can adequately model material response under the complex thermomechanical loading conditions typical of power generation service. The approach adopted was to conduct a series of carefully controlled thermomechanical experiments on a nickel-based superalloy, Hastelloy Alloy X. Previous investigations had shown that this material experiences metallurgical instabilities leading to complex hardening behavior, termed dynamic strain aging. Investigating this phenomenon under full thermomechanical conditions leads to a number of challenging experimental difficulties which up to the present work were unresolved. To correct this situation, a number of advances were made in thermomechanical testing techniques. Advanced methods for dynamic temperature gradient control, phasing control and thermal strain compensation were developed and incorporated into real time test control software. These advances allowed the thermomechanical data to be analyzed with minimal experimental uncertainty. The thermomechanical results were evaluated on both a phenomenological and microstructural basis. Phenomenological results revealed that the thermomechanical hardening trends were not bounded by those displayed under isothermal conditions. For the case of Hastelloy Alloy X (and similar dynamic strain aging materials), this strongly suggests that some form of thermomechanical testing is necessary when characterizing a thermoviscoplastic deformation model. Transmission electron microscopy was used to study the microstructural physics, and analyze the unique phenomenological behavior.

Investigation of Thermo-Magnetic Processing in Application to Heavy Duty Truck Suspension Components

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

Makiewicz, Kurt; Yurek, Theodore; Farrell, Brian

2016-04-19

Thermomagnetic processing (TMP) was examined as a methodology for increasing transformation rate during heat treatment in steel tubes. Two potential benefits were investigated, reduced energy consumption and improved mechanical properties. It is possible to reduce energy consumption with TMP by allowing tempering at lower temperatures and shorter times. Improved mechanical properties are possible by allowing a more copious distribution of fine carbides during tempering of martensite. Improved mechanical properties are also possible by quenching under a magnetic field after austenitization by formation of martensitic twins. The experiments in this work allowed for the following conclusions: the samples could not bemore » quenched fast enough to transform the entire wall thickness to martensite; the knee of the Continuous Cooling Curve (CCT) curve was shifted to the left when quenching following austenitizing in a magnetic field. The magnetic field during tempering did enhance the kinetics and allowed fine carbides to form. Since the through wall thickness was not hardened, the bulk mechanical properties were unaffected by the magnetic field. Hardness measurements after hardening showed that hardening in a magnetic field >0.5T resulted in a significant reduction in hardness. Combined with the inadequate cooling rate it was not possible to properly harden the samples. Tempering at 600 C without a magnetic field resulted in no formation of carbides, but tempering at 600 C and 450 C with a 1-2T field resulted in carbide formation in all samples.« less

FE-simulation of hot forging with an integrated heat treatment with the objective of residual stress prediction

NASA Astrophysics Data System (ADS)

Behrens, Bernd-Arno; Chugreeva, Anna; Chugreev, Alexander

2018-05-01

Hot forming as a coupled thermo-mechanical process comprises numerous material phenomena with a corresponding impact on the material behavior during and after the forming process as well as on the final component performance. In this context, a realistic FE-simulation requires reliable mathematical models as well as detailed thermo-mechanical material data. This paper presents experimental and numerical results focused on the FE-based simulation of a hot forging process with a subsequent heat treatment step aiming at the prediction of the final mechanical properties and residual stress state in the forged component made of low alloy CrMo-steel DIN 42CrMo4. For this purpose, hot forging experiments of connecting rod geometry with a corresponding metallographic analysis and x-ray residual stress measurements have been carried out. For the coupled thermo-mechanical-metallurgical FE-simulations, a special user-defined material model based on the additive strain decomposition method and implemented in Simufact Forming via MSC.Marc solver features has been used.

Numerical model of thermo-mechanical coupling for the tensile failure process of brittle materials

NASA Astrophysics Data System (ADS)

Fu, Yu; Wang, Zhe; Ren, Fengyu; Wang, Daguo

2017-10-01

A numerical model of thermal cracking with a thermo-mechanical coupling effect was established. The theory of tensile failure and heat conduction is used to study the tensile failure process of brittle materials, such as rock and concrete under high temperature environment. The validity of the model is verified by thick-wall cylinders with analytical solutions. The failure modes of brittle materials under thermal stresses caused by temperature gradient and different thermal expansion coefficient were studied by using a thick-wall cylinder model and an embedded particle model, respectively. In the thick-wall cylinder model, different forms of cracks induced by temperature gradient were obtained under different temperature boundary conditions. In the embedded particle model, radial cracks were produced in the medium part with lower tensile strength when temperature increased because of the different thermal expansion coefficient. Model results are in good agreement with the experimental results, thereby providing a new finite element method for analyzing the thermal damage process and mechanism of brittle materials.

When daily planning improves employee performance: The importance of planning type, engagement, and interruptions.

PubMed

Parke, Michael R; Weinhardt, Justin M; Brodsky, Andrew; Tangirala, Subrahmaniam; DeVoe, Sanford E

2018-03-01

Does planning for a particular workday help employees perform better than on other days they fail to plan? We investigate this question by identifying 2 distinct types of daily work planning to explain why and when planning improves employees' daily performance. The first type is time management planning (TMP)-creating task lists, prioritizing tasks, and determining how and when to perform them. We propose that TMP enhances employees' performance by increasing their work engagement, but that these positive effects are weakened when employees face many interruptions in their day. The second type is contingent planning (CP) in which employees anticipate possible interruptions in their work and plan for them. We propose that CP helps employees stay engaged and perform well despite frequent interruptions. We investigate these hypotheses using a 2-week experience-sampling study. Our findings indicate that TMP's positive effects are conditioned upon the amount of interruptions, but CP has positive effects that are not influenced by the level of interruptions. Through this study, we help inform workers of the different planning methods they can use to increase their daily motivation and performance in dynamic work environments. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush).

PubMed

Ottinger, Christopher A; Honeyfield, Dale C; Densmore, Christine L; Iwanowicz, Luke R

2014-05-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP--biologically inactive form) to thiamine pyrophosphate (TPP--biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state. Published by Elsevier Ltd.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush)

USGS Publications Warehouse

Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

2014-01-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

Preparation of polyol esters based on vegetable and animal fats.

PubMed

Gryglewicz, S; Piechocki, W; Gryglewicz, G

2003-03-01

The possibility of using some natural fats: rapeseed oil, olive oil and lard, as starting material for the preparation of neopentyl glycol (NPG) and trimethylol propane (TMP) esters is reported. The syntheses of final products were performed by alcoholysis of fatty acid methyl esters, obtained from natural fats studied, with the appropriate polyhydric alcohol using calcium methoxide as a catalyst. The basic physicochemical properties of the NPG and TMP esters synthesized were the following: viscosity at 40 degrees C in the range of 13.5-37.6 cSt, pour point between -10.5 and -17.5 degrees C and very high viscosity indices, higher than 200. Generally, the esters of neopentyl alcohols were characterized by higher stability in thermo-oxidative conditions in comparison to native triglycerides. Due to the low content of polyunsaturated acids, the olive oil based esters showed the highest thermo-oxidative resistance. Also, methyl esters of fatty acids of lard would constitute a good raw material for the synthesis of lubricating oils, provided that their saturated acids content was lowered. This permits synthesis of NPG and TMP esters with a lower pour point (below -10 degrees C) than natural lard (+33 degrees C).

Validated univariate and multivariate spectrophotometric methods for the determination of pharmaceuticals mixture in complex wastewater

NASA Astrophysics Data System (ADS)

Riad, Safaa M.; Salem, Hesham; Elbalkiny, Heba T.; Khattab, Fatma I.

2015-04-01

Five, accurate, precise, and sensitive univariate and multivariate spectrophotometric methods were developed for the simultaneous determination of a ternary mixture containing Trimethoprim (TMP), Sulphamethoxazole (SMZ) and Oxytetracycline (OTC) in waste water samples collected from different cites either production wastewater or livestock wastewater after their solid phase extraction using OASIS HLB cartridges. In univariate methods OTC was determined at its λmax 355.7 nm (0D), while (TMP) and (SMZ) were determined by three different univariate methods. Method (A) is based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method followed by ratio difference method for determination of TMP and SMZ. Method (B) is successive derivative ratio technique (SDR). Method (C) is mean centering of the ratio spectra (MCR). The developed multivariate methods are principle component regression (PCR) and partial least squares (PLS). The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs. The obtained results are statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

Scleritis Caused by In Vitro Linezolid-Resistant Nocardia asteroides

PubMed Central

Tuli, Sonal

2014-01-01

Purpose. To describe a case of postoperative scleritis caused by a novel strain of Nocardia resistant to linezolid and trimethoprim-sulfamethoxazole (TMP-SMX). Methods. Case report of a patient with microbiologically proven scleritis due to Nocardia asteroides. Results. The patient presented with pain, redness, and nodules on the sclera three months following pterygium excision with mitomycin C and amniotic membrane placement. As no response was noted with empiric treatment for bacterial scleritis, debridement was performed. The cytopathology report showed gram positive filamentous bacteria. A presumptive diagnosis of Nocardia scleritis was made and therapy was initiated based on a literature review on treatments for Nocardia infections. Cultures returned growing Nocardia asteroides. Antibiotic sensitivity testing revealed resistance to linezolid and TMP-SMX which are the traditional drugs of choice for Nocardia. The patient was treated with amikacin and imipenem as well as extensive debridement with pedicle grafts. The patient's scleritis resolved with a good visual outcome. Conclusions. Cultures should be obtained in all cases of necrotizing scleritis in patients with a recent history of conjunctival surgery to rule out unusual organisms such as Nocardia. Although literature states that resistance to linezolid and TMP-SMX is rare in Nocardia, sensitivity testing can be useful in unresponsive cases. PMID:25400961

Scleritis Caused by In Vitro Linezolid-Resistant Nocardia asteroides.

PubMed

Gonzalez, Andres; Fakhar, Kaihan; Gubernick, David; Tuli, Sonal

2014-01-01

Purpose. To describe a case of postoperative scleritis caused by a novel strain of Nocardia resistant to linezolid and trimethoprim-sulfamethoxazole (TMP-SMX). Methods. Case report of a patient with microbiologically proven scleritis due to Nocardia asteroides. Results. The patient presented with pain, redness, and nodules on the sclera three months following pterygium excision with mitomycin C and amniotic membrane placement. As no response was noted with empiric treatment for bacterial scleritis, debridement was performed. The cytopathology report showed gram positive filamentous bacteria. A presumptive diagnosis of Nocardia scleritis was made and therapy was initiated based on a literature review on treatments for Nocardia infections. Cultures returned growing Nocardia asteroides. Antibiotic sensitivity testing revealed resistance to linezolid and TMP-SMX which are the traditional drugs of choice for Nocardia. The patient was treated with amikacin and imipenem as well as extensive debridement with pedicle grafts. The patient's scleritis resolved with a good visual outcome. Conclusions. Cultures should be obtained in all cases of necrotizing scleritis in patients with a recent history of conjunctival surgery to rule out unusual organisms such as Nocardia. Although literature states that resistance to linezolid and TMP-SMX is rare in Nocardia, sensitivity testing can be useful in unresponsive cases.

Combination of micelle collapse and field-amplified sample stacking in capillary electrophoresis for determination of trimethoprim and sulfamethoxazole in animal-originated foodstuffs.

PubMed

Liu, Lihong; Wan, Qian; Xu, Xiaoying; Duan, Shunshan; Yang, Chunli

2017-03-15

An on-line preconcentration method combining micelle to solvent stacking (MSS) with field-amplified sample stacking (FASS) was employed for the analysis of trimethoprim (TMP) and sulfamethoxazole (SMZ) by capillary zone electrophoresis (CZE). The optimized experimental conditions were as followings: (1) sample matrix, 10.0mM SDS-5% (v/v) methanol; (2) trapping solution (TS), 35mM H 3 PO 4 -60% acetonitrile (CH 3 CN); (3) running buffer, 30mM Na 2 HPO 4 (pH=7.3); (4) sample solution volume, 168nL; TS volume, 168nL; and (5) 9kV voltage, 214nm UV detection. Under the optimized conditions, the limits of detection (LODs) for SMZ and TMP were 7.7 and 8.5ng/mL, and they were 301 and 329 times better compared to a typical injection, respectively. The contents of TMP and SMZ in animal foodstuffs such as dairy products, eggs and honey were analyzed, too. Recoveries of 80-104% were acquired with relative standard deviations of 0.5-5.4%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Validated univariate and multivariate spectrophotometric methods for the determination of pharmaceuticals mixture in complex wastewater.

PubMed

Riad, Safaa M; Salem, Hesham; Elbalkiny, Heba T; Khattab, Fatma I

2015-04-05

Five, accurate, precise, and sensitive univariate and multivariate spectrophotometric methods were developed for the simultaneous determination of a ternary mixture containing Trimethoprim (TMP), Sulphamethoxazole (SMZ) and Oxytetracycline (OTC) in waste water samples collected from different cites either production wastewater or livestock wastewater after their solid phase extraction using OASIS HLB cartridges. In univariate methods OTC was determined at its λmax 355.7 nm (0D), while (TMP) and (SMZ) were determined by three different univariate methods. Method (A) is based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method followed by ratio difference method for determination of TMP and SMZ. Method (B) is successive derivative ratio technique (SDR). Method (C) is mean centering of the ratio spectra (MCR). The developed multivariate methods are principle component regression (PCR) and partial least squares (PLS). The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs. The obtained results are statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision at p=0.05. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of carbon nanofibre-reinforced polypropylene foams.

PubMed

Antunes, M; Velasco, J I; Realinho, V; Arencón, D

2010-02-01

In this paper, carbon-nanofibre-reinforced polypropylene foams were prepared and characterized regarding their foaming behaviour, cellular structure and both thermo-mechanical as well as electrical properties. Polypropylene (PP) nanocomposites containing 5, 10 and 20 wt% of carbon nanofibres (CNF) and a chemical blowing agent were prepared by melt-mixing inside a twin-screw extruder and subsequently water-cooled and pelletized. The extruded nanocomposites were later foamed using a one-step compression-moulding process. The thermo-mechanical properties of the CNF-reinforced PP foams were studied, analyzing the influence of the carbon nanofibres on the cellular structure and subsequent thermo-mechanical behaviour of the foams. Carbon nanofibres not only seemed to act as nucleating agents, reducing the average cell size of the foams and increasing their cell density for similar expansion ratios, but also helped produce mechanically-improved foams, even reaching for the 20 wt% CNF-reinforced ones a specific modulus around 1.2 GPa x cm3/g for densities as low as 300 kg/m3. An increasingly higher electrical conductivity was assessed for both the solids as well as the foams with increasing the amount of carbon nanofibres.

On the Prediction of Hot Tearing in Al-to-Steel Welding by Friction Melt Bonding

NASA Astrophysics Data System (ADS)

Jimenez-Mena, N.; Jacques, P. J.; Drezet, J. M.; Simar, A.

2018-07-01

Aluminum alloy AA6061 was welded to dual-phase steel 980 (DP980) by the friction melt bonding (FMB) process. Hot tears have been suppressed by controlling the thermomechanical cycle. In particular, the welding speed and the thermal conductivity of the backing plate have been optimized. A finite-element thermomechanical model coupled with the Rappaz-Drezet-Gremaud (RDG) criterion has been used to explain these experimental observations. The hot tear susceptibility has been reduced with large thermal gradients and with the formation of a cellular microstructure. Both effects are favored by a backing plate made of a material with high thermal conductivity, such as copper.

On the Prediction of Hot Tearing in Al-to-Steel Welding by Friction Melt Bonding

NASA Astrophysics Data System (ADS)

Jimenez-Mena, N.; Jacques, P. J.; Drezet, J. M.; Simar, A.

2018-04-01

Aluminum alloy AA6061 was welded to dual-phase steel 980 (DP980) by the friction melt bonding (FMB) process. Hot tears have been suppressed by controlling the thermomechanical cycle. In particular, the welding speed and the thermal conductivity of the backing plate have been optimized. A finite-element thermomechanical model coupled with the Rappaz-Drezet-Gremaud (RDG) criterion has been used to explain these experimental observations. The hot tear susceptibility has been reduced with large thermal gradients and with the formation of a cellular microstructure. Both effects are favored by a backing plate made of a material with high thermal conductivity, such as copper.

Characterization of Hybrid Epoxy Nanocomposites

PubMed Central

Simcha, Shelly; Dotan, Ana; Kenig, Samuel; Dodiuk, Hanna

2012-01-01

This study focused on the effect of Multi Wall Carbon Nanotubes (MWCNT) content and its surface treatment on thermo-mechanical properties of epoxy nanocomposites. MWCNTs were surface treated and incorporated into two epoxy systems. MWCNT's surface treatments were based on: (a) Titania coating obtained by sol-gel process and (b) a nonionic surfactant. Thermo-mechanical properties improvement was obtained following incorporation of treated MWCNT. It was noticed that small amounts of titania coated MWCNT (0.05 wt %) led to an increase in the glass transition temperature and stiffness. The best performance was achieved adding 0.3 wt % titania coated MWCNT where an increase of 10 °C in the glass transition temperature and 30% in storage modulus were obtained. PMID:28348313

Fatigue crack initiation and microcrack propagation in X7091 type aluminum P/M alloys

NASA Astrophysics Data System (ADS)

Hirose, S.; Fine, M. E.

1983-06-01

Fatigu crack initiation in extruded X7091 RSP-P/M aluminum type alloys o°Curs at grain boundaries at both low and high stresses. By a process of elimination this grain boundary embrittlement was attributed to Al2O3 particles formed mainly during atomization and segregated to some grain boundaries. It is not due to the small grain size, to Co2Al9, to η precipitates at grain boundaries, nor to a precipitate free zone. Thermomechanical processing after extrusion of X7091 with 0.8 pct Co was done by Alcoa to produce large recrystallized grains. This resulted in initiation of fatigue cracks at slip bands, and the resistance to initiation of fatigue cracks at low stresses was much greater. Microcrack growth is, however, much faster in the thermomechanically treated samples, as well as in ingot alloys, than in extruded and aged X7091.

Controlling the mechanical properties of carbon steel by thermomechanical treatment

NASA Astrophysics Data System (ADS)

Balavar, Mohsen; Mirzadeh, Hamed

2018-01-01

The effect of thermomechanical processing and heat treatment on the microstructure and mechanical properties of low carbon steel was studied. It was revealed that the dual phase ferritic-martensitic microstructure shows a good combination of tensile strength and ductility along with superior work hardening response. On the other hand, the bimodal-sized structure containing ultrafine grained (UFG) and micron-sized ferrite phase can be easily produced by cold rolling and annealing of the dual phase starting microstructure. This steel showed high yield stress, tensile strength, and ductility, but poor work hardening ability. The full annealed ferritic-pearlitic sheet with banded morphology exhibited low strength and high total elongation with the appearance of the yield point phenomenon. The martensitic steels, however, had high tensile strength and low ductility. By comparing the tensile properties of these steels, it was shown that it is possible to control the mechanical properties of low carbon steel by simple processing routes.

Mechanical Characterization and Corrosion Testing of X608 Al Alloy

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

Prabhakaran, Ramprashad; Choi, Jung-Pyung; Stephens, Elizabeth V.

2016-02-07

This paper describes the mechanical characterization and corrosion testing of X608 Al alloy that is being considered for A-pillar covers for heavy-duty truck applications. Recently, PNNL developed a thermo-mechanical process to stamp A-pillar covers at room temperature using this alloy, and the full-size prototype was successfully stamped by a tier-1 supplier. This study was conducted to obtain additional important information related to the newly developed forming process, and to further improve its mechanical properties. The solutionization temperature, pre-strain and paint-bake heat-treatment were found to influence the alloy’s fabricability and mechanical properties. Natural aging effect on the formability was investigated bymore » limiting dome height (LDH) tests. Preliminary corrosion experiments showed that the employed thermo-mechanical treatments did not significantly affect the corrosion behavior of Al X608.« less

Computational homogenisation for thermoviscoplasticity: application to thermally sprayed coatings

NASA Astrophysics Data System (ADS)

Berthelsen, Rolf; Denzer, Ralf; Oppermann, Philip; Menzel, Andreas

2017-11-01

Metal forming processes require wear-resistant tool surfaces in order to ensure a long life cycle of the expensive tools together with a constant high quality of the produced components. Thermal spraying is a relatively widely applied coating technique for the deposit of wear protection coatings. During these coating processes, heterogeneous coatings are deployed at high temperatures followed by quenching where residual stresses occur which strongly influence the performance of the coated tools. The objective of this article is to discuss and apply a thermo-mechanically coupled simulation framework which captures the heterogeneity of the deposited coating material. Therefore, a two-scale finite element framework for the solution of nonlinear thermo-mechanically coupled problems is elaborated and applied to the simulation of thermoviscoplastic material behaviour including nonlinear thermal softening in a geometrically linearised setting. The finite element framework and material model is demonstrated by means of numerical examples.

Analysis of intelligent hinged shell structures: deployable deformation and shape memory effect

NASA Astrophysics Data System (ADS)

Shi, Guang-Hui; Yang, Qing-Sheng; He, X. Q.

2013-12-01

Shape memory polymers (SMPs) are a class of intelligent materials with the ability to recover their initial shape from a temporarily fixable state when subjected to external stimuli. In this work, the thermo-mechanical behavior of a deployable SMP-based hinged structure is modeled by the finite element method using a 3D constitutive model with shape memory effect. The influences of hinge structure parameters on the nonlinear loading process are investigated. The total shape memory of the processes the hinged structure goes through, including loading at high temperature, decreasing temperature with load carrying, unloading at low temperature and recovering the initial shape with increasing temperature, are illustrated. Numerical results show that the present constitutive theory and the finite element method can effectively predict the complicated thermo-mechanical deformation behavior and shape memory effect of SMP-based hinged shell structures.

Thermo-Mechanical Calculations of Hybrid Rotary Friction Welding at Equal Diameter Copper Bars and Effects of Essential Parameters on Dependent Special Variables

NASA Astrophysics Data System (ADS)

Parsa, M. H.; Davari, H.; Hadian, A. M.; Ahmadabadi, M. Nili

2007-05-01

Hybrid Rotary Friction Welding is a modified type of common rotary friction welding processes. In this welding method parameters such as pressure, angular velocity and time of welding control temperature, stress, strain and their variations. These dependent factors play an important rule in defining optimum process parameters combinations in order to improve the design and manufacturing of welding machines and quality of welded parts. Thermo-mechanical simulation of friction welding has been carried out and it has been shown that, simulation is an important tool for prediction of generated heat and strain at the weld interface and can be used for prediction of microstructure and evaluation of quality of welds. For simulation of Hybrid Rotary Friction Welding, a commercial finite element program has been used and the effects of pressure and rotary velocity of rotary part on temperature and strain variations have been investigated.

Numerical modeling of fluid migration in subduction zones

NASA Astrophysics Data System (ADS)

Walter, M. J.; Quinteros, J.; Sobolev, S. V.

2015-12-01

It is well known that fluids play a crucial role in subduction evolution. For example, mechanical weakening along tectonic interfaces, due to high fluid pressure, may enable oceanic subduction. Hence, the fluid content seems to be a critical parameter for subduction initiation. Studies have also shown a correlation between the location of slab dehydration and intermediate seismic activity. Furthermore, expelled fluids from the subduction slab affect the melting temperature, consequently, contributing to partial melting in the wedge above the down-going plate and extensive volcanism. In summary, fluids have a great impact on tectonic processes and therefore should be incorporated into geodynamic numerical models. Here we use existing approaches to couple and solve fluid flow equations in the SLIM-3D thermo-mechanical code. SLIM-3D is a three-dimensional thermo-mechanical code capable of simulating lithospheric deformation with elasto-visco-plastic rheology. It has been successfully applied to model geodynamic processes at different tectonic settings, including subduction zones. However, although SLIM-3D already includes many features, fluid migration has not been incorporated into the model yet. To this end, we coupled solid and fluid flow assuming that fluids flow through a porous and deformable solid. Thereby, we introduce a two-phase flow into the model, in which the Stokes flow is coupled with the Darcy law for fluid flow. Ultimately, the evolution of porosity is governed by a compaction pressure and the advection of the porous solid. We show the details of our implementation of the fluid flow into the existing thermo-mechanical finite element code and present first results of benchmarks and experiments. We are especially interested in the coupling of subduction processes and the evolution of the magmatic arc. Thereby, we focus on the key factors controlling magma emplacement and its influence on subduction processes.

Use of Hot Rolling for Generating Low Deviation Twins and a Disconnected Random Boundary Network in Inconel 600 Alloy

NASA Astrophysics Data System (ADS)

Sahu, Sandeep; Yadav, Prabhat Chand; Shekhar, Shashank

2018-02-01

In this investigation, Inconel 600 alloy was thermomechanically processed to different strains via hot rolling followed by a short-time annealing treatment to determine an appropriate thermomechanical process to achieve a high fraction of low-Σ CSL boundaries. Experimental results demonstrate that a certain level of deformation is necessary to obtain effective "grain boundary engineering"; i.e., the deformation must be sufficiently high to provide the required driving force for postdeformation static recrystallization, yet it should be low enough to retain a large fraction of original twin boundaries. Samples processed in such a fashion exhibited 77 pct length fraction of low-Σ CSL boundaries, a dominant fraction of which was from Σ3 ( 64 pct), the latter with very low deviation from its theoretical misorientation. The application of hot rolling also resulted in a very low fraction of Σ1 ( 1 pct) boundaries, as desired. The process also leads to so-called "triple junction engineering" with the generation of special triple junctions, which are very effective in disrupting the connectivity of the random grain boundary network.

Effects of thermomechanical treatments on the microstructures and mechanical properties of GTA-welded AZ31B magnesium alloy

NASA Astrophysics Data System (ADS)

Chu, Ya-jie; Chen, Jian; Li, Xiao-quan; Wu, Shen-qing; Yang, Zong-hui

2012-10-01

Thermomechanical treatments were carried out to improve the properties of AZ31B joints prepared by gas tungsten arc welding. The microstructures of the joints were studied by optical microscopy and scanning electron microscopy with energy-dispersive spectrometry. Tensile tests and hardness tests were performed to investigate the effects of thermomechanical treatments on the mechanical properties of the joints. It is found that the thermomechanical-treated joints show superior mechanical properties against the as-welded joints, and their ultimate tensile strength can reach more than 92% of the base material. This mainly attributes to the formation of fine equiaxed grains in the fusion zone. After thermomechanical treatments the dendrites are transformed to fine spherical grains, and the dendritic segregation can be effectively eliminated.

Comparison of Diafiltration and Size-Exclusion Chromatography to Recover Hemicelluloses From Process Water From Thermomechanical Pulping of Spruce

NASA Astrophysics Data System (ADS)

Andersson, Alexandra; Persson, Tobias; Zacchi, Guido; Stålbrand, Henrik; Jönsson, Ann-Sofi

Hemicelluloses constitute one of the most abundant renewable resources on earth. To increase their utilization, the isolation of hemicelluloses from industrial biomass side-streams would be beneficial. A method was investigated to isolate hemicelluloses from process water from a thermomechanical pulp mill. The method consists of three steps: removal of solids by microfiltration, preconcentration of the hemicelluloses by ultrafiltration, and purification by either size-exclusion chromatography (SEC) or diafiltration. The purpose of the final purification step is to separate hemicelluloses from small oligosaccharides, monosaccharides, and salts. The ratio between galactose, glucose, and mannose in oligo- and polysaccharides after preconcentration was 0.8∶1∶2.8, which is similar to that found in galactoglucomannan. Continuous diafiltration was performed using a composite fluoro polymer membrane with cutoff of 1000 Da. After diafiltration with four diavolumes the purity of the hemicelluloses was 77% (gram oligo- and polysaccharides/ gram total dissolved solids) and the recovery was 87%. Purification by SEC was performed with 5, 20, and 40% sample loadings, respectively and a flow rate of 12 or 25 mL/min (9 or 19 cm/h). The purity of hemicelluloses after SEC was approx 82%, and the recovery was above 99%. The optimal sample load and flow rate were 20% and 25 mL/min, respectively. The process water from thermomechanical pulping of spruce is inexpensive. Thus, the recovery of hemicelluloses is not of main importance. If the purity of 77%, obtained with diafiltration, is sufficient for the utilization of the hemicelluloses, diafiltration probably offers a less expensive alternative in this application.

Functional Neuroprotection and Efficient Regulation of GDNF Using Destabilizing Domains in a Rodent Model of Parkinson's Disease

PubMed Central

Quintino, Luis; Manfré, Giuseppe; Wettergren, Erika Elgstrand; Namislo, Angrit; Isaksson, Christina; Lundberg, Cecilia

2013-01-01

Glial cell line–derived neurotrophic factor (GDNF) has great potential to treat Parkinson's disease (PD). However, constitutive expression of GDNF can over time lead to side effects. Therefore, it would be useful to regulate GDNF expression. Recently, a new gene inducible system using destabilizing domains (DD) from E. coli dihydrofolate reductase (DHFR) has been developed and characterized. The advantage of this novel DD is that it is regulated by trimethoprim (TMP), a well-characterized drug that crosses the blood–brain barrier and can therefore be used to regulate gene expression in the brain. We have adapted this system to regulate expression of GDNF. A C-terminal fusion of GDNF and a DD with an additional furin cleavage site was able to be efficiently regulated in vitro, properly processed and was able to bind to canonical GDNF receptors, inducing a signaling cascade response in target cells. In vivo characterization of the protein showed that it could be efficiently induced by TMP and it was only functional when gene expression was turned on. Further characterization in a rodent model of PD showed that the regulated GDNF protected neurons, improved motor behavior of animals and was efficiently regulated in a pathological setting. PMID:23881415

Slave finite elements for nonlinear analysis of engine structures, volume 1

NASA Technical Reports Server (NTRS)

Gellin, S.

1991-01-01

A 336 degrees of freedom slave finite element processing capability to analyze engine structures under severe thermomechanical loading is presented. Description of the theoretical development and demonstration of that element is presented in this volume.

Viscoplastic constitutive relationships with dependence on thermomechanical history

NASA Technical Reports Server (NTRS)

Robinson, D. N.; Bartolotta, P. A.

1985-01-01

Experimental evidence of thermomechanical history dependence in the cyclic hardening behavior of some common high-temperature structural alloys is presented with special emphasis on dynamic metallurgical changes. The inadequacy of formulating nonisothermal constitutive equations solely on the basis of isothermal testing is discussed. A representation of thermoviscoplasticity is proposed that qualitatively accounts for the observed hereditary behavior. This is achieved by formulating the scalar evolutionary equation in an established viscoplasticity theory to reflect thermomechanical path dependence. To assess the importance of accounting for thermomechanical history dependence in practical structural analyses, two qualitative models are specified: (1) formulated as if based entirely on isothermal information; (2) to reflect thermomechanical path dependence using the proposed thermoviscoplastic representation. Predictions of the two models are compared and the impact the calculated differences in deformation behavior may have on subsequent lifetime predictions is discussed.

Damage mechanisms in bithermal and thermomechanical fatigue of Haynes 188

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Halford, Gary R.

1992-01-01

Post failure fractographic and metallographic studies were conducted on Haynes 188 specimens fatigued under bithermal and thermomechanical loading conditions between 316 and 760 C. Bithermal fatigue specimens examined included those tested under high strain rate in-phase and out-phase, tensile creep in-phase, and compressive creep out-of-phase loading conditions. Specimens tested under in-phase and out-of-phase thermomechanical fatigue were also examined. The nature of failure mode (transgrandular versus intergranular), the topography of the fracture surface, and the roles of oxidation and metallurgical changes were studied for each type of bithermal and thermomechanical test.

Integrated manufacturing approach to attain benchmark team performance

NASA Astrophysics Data System (ADS)

Chen, Shau-Ron; Nguyen, Andrew; Naguib, Hussein

1994-09-01

A Self-Directed Work Team (SDWT) was developed to transfer a polyimide process module from the research laboratory to our wafer fab facility for applications in IC specialty devices. The SDWT implemented processes and tools based on the integration of five manufacturing strategies for continuous improvement. These were: Leadership Through Quality (LTQ), Total Productive Maintenance (TMP), Cycle Time Management (CTM), Activity-Based Costing (ABC), and Total Employee Involvement (TEI). Utilizing these management techniques simultaneously, the team achieved six sigma control of all critical parameters, increased Overall Equipment Effectiveness (OEE) from 20% to 90%, reduced cycle time by 95%, cut polyimide manufacturing cost by 70%, and improved its overall team member skill level by 33%.

Kinetic measurement of 2-aminopurine X cytosine and 2-aminopurine X thymine base pairs as a test of DNA polymerase fidelity mechanisms.

PubMed Central

Watanabe, S M; Goodman, M F

1982-01-01

Enzyme kinetic measurements are presented showing that Km rather than maximum velocity (Vmax) discrimination governs the frequency of forming 2-aminopurine X cytosine base mispairs by DNA polymerase alpha. An in vitro system is used in which incorporation of dTMP or dCMP occurs opposite a template 2-aminopurine, and values for Km and Vmax are obtained. Results from a previous study in which dTTP and dCTP were competing simultaneously for insertion opposite 2-aminopurine indicated that dTMP is inserted 22 times more frequently than dCMP. We now report that the ratio of Km values KCm/KTm = 25 +/- 6, which agrees quantitatively with the dTMP/dCMP incorporation ratio obtained previously. We also report that VCmax is indistinguishable from VTmax. These Km and Vmax data are consistent with predictions from a model, the Km discrimination model, in which replication fidelity is determined by free energy differences between matched and mismatched base pairs. Central to this model is the prediction that the ratio of Km values for insertion of correct and incorrect nucleotides specifies the insertion fidelity, and the maximum velocities of insertion are the same for both nucleotides. PMID:6959128

The structures of thymidine kinase from herpes simplex virus type 1 in complex with substrates and a substrate analogue.

PubMed Central

Wild, K.; Bohner, T.; Folkers, G.; Schulz, G. E.

1997-01-01

Thymidine kinase from Herpes simplex virus type 1 (TK) was crystallized in an N-terminally truncated but fully active form. The structures of TK complexed with ADP at the ATP-site and deoxythymidine-5'-monophosphate (dTMP), deoxythymidine (dT), or idoxuridine-5'-phosphate (5-iodo-dUMP) at the substrate-site were refined to 2.75 A, 2.8 A, and 3.0 A resolution, respectively. TK catalyzes the phosphorylation of dT resulting in an ester, and the phosphorylation of dTMP giving rise to an anhydride. The presented TK structures indicate that there are only small differences between these two modes of action. Glu83 serves as a general base in the ester reaction. Arg163 parks at an internal aspartate during ester formation and binds the alpha-phosphate of dTMP during anhydride formation. The bound deoxythymidine leaves a 35 A3 cavity at position 5 of the base and two sequestered water molecules at position 2. Cavity and water molecules reduce the substrate specificity to such an extent that TK can phosphorylate various substrate analogues useful in pharmaceutical applications. TK is structurally homologous to the well-known nucleoside monophosphate kinases but contains large additional peptide segments. PMID:9336833

Thiamine Nutritional Status and Depressive Symptoms Are Inversely Associated among Older Chinese Adults123

PubMed Central

Zhang, Geng; Ding, Hanqing; Chen, Honglei; Ye, Xingwang; Li, Huaixing; Lin, Xu; Ke, Zunji

2013-01-01

Thiamine has been hypothesized to play an important role in mental health; however, few studies have investigated the association between thiamine nutritional status and depression in the general population. Concentrations of free thiamine and its phosphate esters [thiamine monophosphate (TMP) and thiamine diphosphate (TDP)] in erythrocytes were measured by HPLC among 1587 Chinese men and women aged 50–70 y. The presence of depressive symptoms was defined as a Center for Epidemiological Studies Depression Scale score of ≥16. The median erythrocyte concentration (nmol/L) was 3.73 for free thiamine, 3.74 for TMP, and 169 for TDP. The overall prevalence of depressive symptoms was 11.3%. Lower concentrations of all 3 erythrocyte thiamine biomarkers were monotonically associated with a higher prevalence of depressive symptoms: the multivariable adjusted ORs comparing the lowest with the highest quartiles were 2.97 (95% CI = 1.87, 4.72; P-trend < 0.001) for free thiamine, 3.46 (95% CI = 1.99, 6.02; P-trend < 0.001) for TMP, and 1.98 (95% CI = 1.22, 3.21; P-trend = 0.002) for TDP. In conclusion, poorer thiamine nutritional status and higher odds of depressive symptoms were associated among older Chinese adults. This finding should be further investigated in prospective or interventional studies. PMID:23173173

Tetramethylpyrazine Effects on the Expression of Scar-Related Genes in Rabbit Benign Biliary Stricture Fibroblasts.

PubMed

Li, Ke Yue; Shi, Cheng Xian; Huang, Jian Zhao; Tang, Ke Li

2016-10-01

To investigate the effects of tetramethylpyrazine (TMP) on transforming growth factor-β1 (TGF- β1), α-smooth muscle actin (α-SMA), and neuronal regeneration related protein (P311) in benign biliary stricture fibroblasts of rabbit. An experimental study. Guizhou Medical University, Guiyang, Guizhou, China, from April to December 2015. Fibroblasts isolated from rabbits following benign biliary stricture were cultured and treated with different concentrations of TMP(0.08, 0.4, and 2.0 mg/ml). TMP-treated cells and non-treated control groups were incubated for 48-hours, and proliferation was assessed using the cell counting kit-8 assay. The mRNAexpressions of TGF-β1, α-SMA, and P311 were assessed by quantitative RT-PCR. Protein expressions of TGF-β1 and α-SMAwere investigated by Western blotting. Treatment with TMPsignificantly reduced the proliferation of benign biliary stricture fibroblasts, and significantly attenuated both the mRNAand protein expressions of TGF-β1, α-SMA, and P311 (p < 0.05) in a dose-dependent manner. TMPsignificantly reduced the proliferation of benign biliary stricture fibroblasts, and significantly downregulated the mRNA/protein expression of TGF-β1, α-SMA, and P311. Therefore, TMPmay be a therapeutic option for the prevention of benign biliary stricture.

Development and Validation of a Multidimensional Expectation Questionnaire for Thalassaemia Major Patients

PubMed Central

Koutelekos, Ioannis G.; Kyritsi, Helen; Makis, Alexandros; Vassalos, Constantine M; Ktenas, Eftychios; Polikandrioti, Maria; Tzoumaka-Bakoula, Chryssa; Chaliasos, Nikolaos

2016-01-01

Nowadays, thalassaemia major (TM) patients are surviving into mature young adulthood; however, no published instrument exists to measure the expectations’ dimensionality among older TM patients in their thirties. This study seeks to validate a novel multidimensional expectation questionnaire suitable for TM patients (MEQ-TMP) reaching their fourth decade of life. In order to establish the psychometric properties of the instrument, data analysis was carried out. The principal component analysis revealed four components (‘Supportive social network’; ‘Raising one’s own family’; ‘Career advancement’; ‘Ability of daily activities’). Their cumulative contribution rate was 66.32%. Cronbach’s alpha for the total scale was 0.87. Each subscale had an alpha value above 0.70; three subscales were in the 0.80 range. MEQ-TMP reliability was proved to be good. The known-group method served as a strategy in examining the operationalisation of the questionnaire’s constructs. The present MEQ-TMP, developed for the aged group of TM patients, would be a useful tool for clinical personnel providing care to TM patients in understanding their outlook on life as they are growing up, to have better psychosocial adjustment to illness chronicity, live life as normally as possible, and fulfill their ambitions; thus enhancing their life satisfaction and quality of life. PMID:26383219

Thiamine nutritional status and depressive symptoms are inversely associated among older Chinese adults.

PubMed

Zhang, Geng; Ding, Hanqing; Chen, Honglei; Ye, Xingwang; Li, Huaixing; Lin, Xu; Ke, Zunji

2013-01-01

Thiamine has been hypothesized to play an important role in mental health; however, few studies have investigated the association between thiamine nutritional status and depression in the general population. Concentrations of free thiamine and its phosphate esters [thiamine monophosphate (TMP) and thiamine diphosphate (TDP)] in erythrocytes were measured by HPLC among 1587 Chinese men and women aged 50-70 y. The presence of depressive symptoms was defined as a Center for Epidemiological Studies Depression Scale score of ≥16. The median erythrocyte concentration (nmol/L) was 3.73 for free thiamine, 3.74 for TMP, and 169 for TDP. The overall prevalence of depressive symptoms was 11.3%. Lower concentrations of all 3 erythrocyte thiamine biomarkers were monotonically associated with a higher prevalence of depressive symptoms: the multivariable adjusted ORs comparing the lowest with the highest quartiles were 2.97 (95% CI = 1.87, 4.72; P-trend < 0.001) for free thiamine, 3.46 (95% CI = 1.99, 6.02; P-trend < 0.001) for TMP, and 1.98 (95% CI = 1.22, 3.21; P-trend = 0.002) for TDP. In conclusion, poorer thiamine nutritional status and higher odds of depressive symptoms were associated among older Chinese adults. This finding should be further investigated in prospective or interventional studies.

Influence of subsolvus thermomechanical processing on the low-cycle fatigue properties of haynes 230 alloy

NASA Astrophysics Data System (ADS)

Vecchio, Kenneth S.; Fitzpatrick, Michael D.; Klarstrom, Dwaine

1995-03-01

Strain-controlled low-cycle fatigue tests have been conducted in air at elevated temperature to determine the influence of subsolvus thermomechanical processing on the low-cycle fatigue (LCF) behavior of HAYNES 230 alloy. A series of tests at various strain ranges was conducted on material experimentally processed at 1121 °C, which is below the M23C6 carbide solvus temperature, and on material fully solution annealed at 1232 °C. A comparative strain-life analysis was performed on the LCF results, and the cyclic hardening/softening characteristics were examined. At 760 °C and 871 °C, the fatigue life of the experimental 230/1121 material was improved relative to the standard 230/1232 material up to a factor of 3. The fatigue life advantage of the experimental material was related primarily to a lower plastic (inelastic) strain amplitude response for a given imposed total strain range. It appears the increase in monotonic flow stress exhibited by the finer grain size experimental material has been translated into an increase in cyclic flow stress at the 760 °C and 871 °C test temperatures. Both materials exhibited entirely transgranular fatigue crack initiation and propagation modes at these temperatures. The LCF performance of the experimental material in tests performed at 982 °C was improved relative to the standard material up to a factor as high as 2. The life advantage of the 230/1121 material occurred despite having a larger plastic strain amplitude than the standard 230/1232 material for a given total strain range. Though not fully understood at present, it is suspected that this behavior is related to the deleterious influence of grain boundaries in the fatigue crack initiations of the standard processed material relative to the experimental material, and ultimately to differences in carbide morphology as a result of thermomechanical processing.

Bacterial pneumonia, HIV therapy, and disease progression among HIV-infected women in the HIV epidemiologic research (HER) study.

PubMed

Kohli, Rakhi; Lo, Yungtai; Homel, Peter; Flanigan, Timothy P; Gardner, Lytt I; Howard, Andrea A; Rompalo, Anne M; Moskaleva, Galina; Schuman, Paula; Schoenbaum, Ellie E

2006-07-01

To determine the rate and predictors of community-acquired bacterial pneumonia and its effect on human immunodeficiency virus (HIV) disease progression in HIV-infected women, we performed a multiple-site, prospective study of HIV-infected women in 4 cities in the United States. During the period of 1993-2000, we observed 885 HIV-infected and 425 HIV-uninfected women with a history of injection drug use or high-risk sexual behavior. Participants underwent semiannual interviews, and CD4+ lymphocyte count and viral load were assessed in HIV-infected subjects. Data regarding episodes of bacterial pneumonia were ascertained from medical record reviews. The rate of bacterial pneumonia among 885 HIV-infected women was 8.5 cases per 100 person-years, compared with 0.7 cases per 100 person-years in 425 HIV-uninfected women (P < .001). In analyses limited to follow-up after 1 January 1996, highly active antiretroviral therapy (HAART) and trimethoprim-sulfamethoxazole (TMP-SMX) use were associated with a decreased risk of bacterial pneumonia. Among women who had used TMP-SMX for 12 months, each month of HAART decreased bacterial pneumonia risk by 8% (adjusted hazard ratio [HR(adj)], 0.92; 95% confidence interval [CI], 0.89-0.95). Increments of 50 CD4+ cells/mm3 decreased the risk (HR(adj), 0.88; 95% CI, 0.84-0.93), and smoking doubled the risk (HR(adj), 2.12; 95% CI, 1.26-3.55). Bacterial pneumonia increased mortality risk (HR(adj), 5.02; 95% CI, 2.12-11.87), with adjustment for CD4+ lymphocyte count and duration of HAART and TMP-SMX use. High rates of bacterial pneumonia persist among HIV-infected women. Although HAART and TMP-SMX treatment decreased the risk, bacterial pneumonia was associated with an accelerated progression to death. Interventions that improve HAART utilization and promote smoking cessation among HIV-infected women are warranted.

Qualitative evaluation of the Teenage Mothers Project in Uganda: a community-based empowerment intervention for unmarried teenage mothers

PubMed Central

2013-01-01

Background A large proportion of unmarried teenage mothers in Uganda face physical, psychological, and social problems after pregnancy and childbirth, such as obstetric complications, lack of education, and stigmatisation in their communities. The Teenage Mothers Project (TMP) in Eastern Uganda empowers unmarried teenage mothers to cope with the consequences of early pregnancy and motherhood. Since 2000, 1036 unmarried teenage mothers, their parents, and community leaders participated in economic and social empowerment interventions. The present study explored the changes resulting from the TMP as well as factors that either enabled or inhibited these changes. Methods Semi-structured interviews (N = 23) were conducted with former teenage mothers , community leaders, and project implementers, and lifeline histories were obtained from former teenage mothers (N = 9). Quantitative monitoring data regarding demographic and social characteristics of teenage mother participants (N = 1036) were analysed. Results The findings suggest that, overall, the TMP seems to have contributed to the well-being of unmarried teenage mothers and to a supportive social environment. It appears that the project contributed to supportive community norms towards teenage mothers’ position and future opportunities, increased agency, improved coping with early motherhood and stigma, continued education, and increased income generation by teenage mothers. The study findings also suggest limited change in disapproving community norms regarding out-of-wedlock sex and pregnancy, late active enrolment of teenage mothers in the project (i.e., ten months after delivery of the child), and differences in the extent to which parents provided support. Conclusions It is concluded that strengths of the community-based TMP seem to be its socio-ecological approach, the participatory planning with community leaders and other stakeholders, counselling of parents and unmarried teenage mothers, and the emphasis on education and income generation. The project can improve by earlier active participation of unmarried pregnant adolescents and increased support for parents. PMID:24011141

Effects of polyphosphates and fluoride on hydroxyapatite dissolution: A pH-stat investigation.

PubMed

do Amaral, Jackeline Gallo; Delbem, Alberto Carlos Botazzo; Pessan, Juliano Pelim; Manarelli, Michele Mauricio; Barbour, Michele E

2016-03-01

This study investigated the immediate and sustained effect of sodium trimetaphosphate (TMP) and sodium hexametaphosphate (HMP) associated or not with fluoride (F) on hydroxyapatite (HA) dissolution using an erosion-like model, considering as well as the influence of salivary coating. Baseline dissolution rates were determined for HA discs using a pH-stat system. In the first set of experiments, HA discs were treated with 1100μgF/mL, 1% or 8% of HMP, 1% or 8% of TMP and 1100μgF/mL associated with 1% or 8% of HMP or TMP, totaling 9 groups (n=8). In a second phase, HA discs were kept in pooled human saliva at 37°C for 2h before treatment with deionised water and 1100μgF/mL associated with 1% or 8% of HMP or TMP, totaling 5 groups (n=8). The post-treatment dissolution rate was determined from three consecutive 30-min assays. Data were analysed using 2 and 3-way ANOVA followed by Fisher and Holm-Sidak methods, respectively (α=0.05). All test solutions promoted reduction in HA dissolution rate when compared to baseline control in the first post-treatment run (p<0.001). However, a synergistic effect was only observed between fluoride and 1% HMP. Moreover, the duration of inhibitory effect was greater when 8% HMP and 1 or 8% HMP associated with F were assessed (p<0.001). The presence of salivary coating led to higher protection for all groups when compared to discs without coating (p<0.001). The reduction of HA dissolution rate, as well as the duration of this effect were influenced by fluoride, type and concentration of phosphate salt and the presence of a salivary coating. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cost-benefit analysis on the use of telemedicine program of Kosova for continuous medical education: a sustainable and efficient model to rebuild medical systems in developing countries.

PubMed

Latifi, Kalterina; Lecaj, Ismet; Bekteshi, Flamur; Dasho, Erion; Doarn, Charles R; Merrell, Ronald C; Latifi, Rifat

2011-12-01

The Ministry of Health of Kosova has recently announced the Telemedicine Program of Kosova (TMPK) as the official institution responsible for managing and coordinating the nation's Long-Distance Continuous Medical Education (CME) program. There are a lack of studies on cost-benefit analysis (CBA) and other economic evaluations of telemedicine programs (TMP), in particular the financial value of CME offered through such a service. In addition, there is lack of prospective studies on Monitoring & Evaluation (M&E) of TMP. The goal of this study was to conduct a retrospective CBA of prospective data collected at TMPK over a 5-year period (2005-2010) in order to determine the cost benefit as opposed to the alternative method of delivery of this model for developing countries whose healthcare systems are in disarray. We reviewed data on the number of participants in virtual lectures both at the Telemedicine Center of Kosova (TCK) as well as the number of participants at six Regional Telemedicine Centers throughout Kosova, the number of lectures broadcasted, the clinical cases reviewed and transmitted for international consultation, and other quantitative data. Only in 2009, approximately 2,000 CME certificates were awarded to physicians and nurses of Kosova, 18 international teleconsultations were conducted, 138 videoconferences, lectures, and seminars were held, and there were over 9,000 visitors at the TCK e-library. Data analysis shows that the TMPK has been an efficient mechanism for CME and sustainable model for rebuilding the medical system. TMPK has been successful in offering physicians, nurses, and other medical professions access to electronic information. TMP is an efficient mechanism to ensure CME and rebuilding medical systems in developing countries. There is a need for prospective CBA of any TMP and the establishment of M&E programs in any future telemedicine initiatives in developing countries.

Ribozyme-mediated cleavage of c-fos mRNA reduces gene expression of DNA synthesis enzymes and metallothionein.

PubMed Central

Scanlon, K J; Jiao, L; Funato, T; Wang, W; Tone, T; Rossi, J J; Kashani-Sabet, M

1991-01-01

The c-fos gene product Fos has been implicated in many cellular processes, including signal transduction, DNA synthesis, and resistance to antineoplastic agents. A fos ribozyme (catalytic RNA) was designed to evaluate the effects of suppressing Fos protein synthesis on expression of enzymes involved in DNA synthesis, DNA repair, and drug resistance. DNA encoding the fos ribozyme (fosRb) was cloned into the pMAMneo expression plasmid, and the resultant vector was transfected into A2780DDP cells resistant to the chemotherapeutic agent cisplatin. The parental drug-sensitive A2780S cells were transfected with the pMMV vector containing the c-fos gene. Morphological alterations were accompanied by significant changes in pharmacological sensitivity in both c-fos- and fosRb-transfected cells. pMAMneo fosRb transfectants revealed decreased c-fos gene expression, concomitant with reduced thymidylate (dTMP) synthase, DNA polymerase beta, topoisomerase I, and metallothionein IIA mRNAs. In contrast, c-myc expression was elevated after fos ribozyme action. Insertion of a mutant ribozyme, mainly capable of antisense activity, into A2780DDP cells resulted in smaller reductions in c-fos gene expression and in cisplatin resistance than the active ribozyme. These studies establish a role for c-fos in drug resistance and in mediating DNA synthesis and repair processes by modulating expression of genes such as dTMP synthase, DNA polymerase beta, and topoisomerase I. These studies also suggest the utility of ribozymes in the analysis of cellular gene expression. Images PMID:1660142

Imaging ultrafast excited state pathways in transition metal complexes by X-ray transient absorption and scattering using X-ray free electron laser source

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

Chen, Lin X.; Shelby, Megan L.; Lestrange, Patrick J.

2016-01-01

This report will describe our recent studies of transition metal complex structural dynamics on the fs and ps time scales using an X-ray free electron laser source, Linac Coherent Light Source (LCLS). Ultrafast XANES spectra at the Ni K-edge of nickel(II) tetramesitylporphyrin (NiTMP) were successfully measured for optically excited state at a timescale from 100 fs to 50 ps, providing insight into its sub-ps electronic and structural relaxation processes. Importantly, a transient reduced state Ni(I) (π, 3dx2-y2) electronic state is captured through the interpretation of a short-lived excited state absorption on the low-energy shoulder of the edge, which is aidedmore » by the computation of X-ray transitions for postulated excited electronic states. The observed and computed inner shell to valence orbital transition energies demonstrate and quantify the influence of electronic configuration on specific metal orbital energies. A strong influence of the valence orbital occupation on the inner shell orbital energies indicates that one should not use the transition energy from 1s to other orbitals to draw conclusions about the d-orbital energies. For photocatalysis, a transient electronic configuration could influence d-orbital energies up to a few eV and any attempt to steer the reaction pathway should account for this to ensure that external energies can be used optimally in driving desirable processes. NiTMP structural evolution and the influence of the porphyrin macrocycle conformation on relaxation kinetics can be likewise inferred from this study.« less

Thermo-mechanical design and testing of a microbalance for space applications

NASA Astrophysics Data System (ADS)

Scaccabarozzi, Diego; Saggin, Bortolino; Tarabini, Marco; Palomba, Ernesto; Longobardo, Andrea; Zampetti, Emiliano

2014-12-01

This work focuses on the thermo-mechanical design of the microbalance used for the VISTA (Volatile In Situ Thermogravimetry Analyzer) sensor. VISTA has been designed to operate in situ in different space environments (asteroids, Mars, icy satellites). In this paper we focus on its application on Mars, where the expected environmental conditions are the most challenging for the thermo-mechanical design. The microbalance holding system has been designed to ensure piezoelectric crystal integrity against the high vibration levels during launch and landing and to cope with the unavoidable thermo-elastic differential displacements due to CTE and temperature differences between the microbalance elements. The crystal holding system, based on three symmetrical titanium supports, provides also the electrical connections needed for crystal actuation, microbalance heating and temperature measurement on the electrode area. On the microbalance crystal surfaces the electrodes, a micro film heater (optimized to perform thermo-gravimetric analysis up to 400 °C) and a resistive thermometer are deposited through a vacuum sputtering process. A mockup of the system has been manufactured and tested at the expected vibration levels and the thermal control effectiveness has been verified in thermo-vacuum environment.

Mechanical and thermomechanical properties of radiation modified poly(ethylene-octene)/Ni-Zn ferrite nanocomposites

NASA Astrophysics Data System (ADS)

Reinholds, I.; Kalkis, V.; Zicans, J.; Merijs Meri, R.; Bockovs, I.; Grigalovica, A.; Muizzemnieks, G.

2013-12-01

Poly(ethylene-1-octene) copolymer (POE) composites filled with nickel-zinc ferrite nanoparticles have been modified by exposure to an electron beam at doses up to 500 kGy. The influence of radiation dose and ferrite content on mechanical properties has been investigated. Thermomechanical properties - thermorelaxation stresses formed in thermal heating and thermo residual stresses resulting in the process of full setting and cooling of materials have been investigated for radiation cross-linked oriented (extended up to 100%) composite samples. Increase of concentration of ferrite particles and increase of radiation dose affects a notable increase of elastic modulus and reduces the deformability in comparison to entire elastomer. Improvement of thermomechanical properties especially at low irradiation doses (100-150 kGy) have been detected for composites with increase of ferrite filler content up to 5 wt. %. It was found that gel content of POE increased up to 85% for pristine POE material with increase of irradiation dose up to 500 kGy due to the formation of cross-linked structure, increase of filler concentration up to 5 wt. % affect reduction in gel fraction due to uniform dispersion in amorphous (ethylene and substituted with hexyl branches) POE phases.

Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

NASA Astrophysics Data System (ADS)

Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

2018-04-01

This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111||ND-oriented grains, while WE showed a more random distribution of 111||ND-, 011||ND-, and 001||ND-oriented grains with a lower intensity.

Thermomechanical In Situ Monitoring of Bi2Te3 Thin Film and Its Relationship with Microstructure and Thermoelectric Performances

NASA Astrophysics Data System (ADS)

Jeong, Min-Woo; Na, Sekwon; Shin, Haishan; Park, Hong-Bum; Lee, Hoo-Jeong; Joo, Young-Chang

2018-07-01

Performance enhancement has been studied for thin-film thermoelectric materials for small-scale energy applications. The microstructural evolution of bismuth telluride (Bi2Te3) was investigated with respect to performance enhancement via in situ thermomechanical analysis due to the post-annealing process. The thermomechanical behavior of Bi2Te3 changes gradually at approximately 200 °C with the formation of a quintuple-layer structure, which was confirmed by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. It was found that highly oriented (006), (0015) was formed with a quintuple-layer structure parallel to the substrate, and the E g 2 Raman vibration mode of Bi2Te3 significantly increased after forming the layer structure with decreased defects. Therefore, the slope of the stress curve was affected by the longer atomic distance of the van der Waals bonds with the formation of (00 l) oriented layered-structure grain. The decreased number of defects in the layer structure affects the electrical and thermal properties of the Bi2Te3 thin film. Due to the microstructural evolution, the power factor of Bi2Te3 was enhanced by approximately 14.8 times by the quintuple-layer structure of Bi2Te3 formed during the annealing process, which contributed to a better understanding of the performance enhancement via post-annealing and to research on other highly oriented layer structure materials.

Thermomechanical In Situ Monitoring of Bi2Te3 Thin Film and Its Relationship with Microstructure and Thermoelectric Performances

NASA Astrophysics Data System (ADS)

Jeong, Min-Woo; Na, Sekwon; Shin, Haishan; Park, Hong-Bum; Lee, Hoo-Jeong; Joo, Young-Chang

2018-04-01

Performance enhancement has been studied for thin-film thermoelectric materials for small-scale energy applications. The microstructural evolution of bismuth telluride (Bi2Te3) was investigated with respect to performance enhancement via in situ thermomechanical analysis due to the post-annealing process. The thermomechanical behavior of Bi2Te3 changes gradually at approximately 200 °C with the formation of a quintuple-layer structure, which was confirmed by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. It was found that highly oriented (006), (0015) was formed with a quintuple-layer structure parallel to the substrate, and the Eg 2Raman vibration mode of Bi2Te3 significantly increased after forming the layer structure with decreased defects. Therefore, the slope of the stress curve was affected by the longer atomic distance of the van der Waals bonds with the formation of (00l) oriented layered-structure grain. The decreased number of defects in the layer structure affects the electrical and thermal properties of the Bi2Te3 thin film. Due to the microstructural evolution, the power factor of Bi2Te3 was enhanced by approximately 14.8 times by the quintuple-layer structure of Bi2Te3 formed during the annealing process, which contributed to a better understanding of the performance enhancement via post-annealing and to research on other highly oriented layer structure materials.

Effect of Thermomechanical Processing and Crystallographic Orientation on the Corrosion Behavior of API 5L X70 Pipeline Steel

NASA Astrophysics Data System (ADS)

Ohaeri, Enyinnaya; Omale, Joseph; Eduok, Ubong; Szpunar, Jerzy

2018-06-01

This work presents the electrochemical response of X70 pipeline steel substrates thermomechanically processed at different conditions. The WE sample was hot rolled at a temperature range of 850 °C to 805 °C and cooled at a rate of 42.75 °C/s. Another sample WD was hot rolled from 880 °C to 815 °C and cooled at a faster rate of 51.5 °C/s. Corrosion tests were conducted electrochemically by potentiodynamic polarization in hydrogen-charged and non-hydrogen-charged environments. A lower corrosion rate was measured with hydrogen charging due to the rapid formation of corrosion product film on pipeline substrate, but WE specimen emerged as the most susceptible to corrosion with and without hydrogen charging. Variations in thermomechanical rolling conditions influenced grain orientation, protective film properties, corrosion, and cracking behavior on both specimens. Cracks were seen in both specimens after hydrogen charging, but specimen WE experienced a more intense deterioration of protective corrosion product film and subsequent cracking. A large part of specimen WD retained its protective corrosion product film after the polarization test, and sites where spalling occurred resulted in pitting with less cracking. Despite weak crystallographic texture noticed in both specimens, WD showed a higher intensity of corrosion-resistant 111|| ND-oriented grains, while WE showed a more random distribution of 111|| ND-, 011|| ND-, and 001|| ND-oriented grains with a lower intensity.

A Thermodynamic and Kenetic Study of the Heterolytic Activation of Hydrogen by Frustrated Borane-Amine Lewis Pairs

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

Karkamkar, Abhijeet J.; Parab, Kshitij; Camaioni, Donald M.

2013-01-21

Calorimetry is used to measure the reaction enthalpies of hydrogen activation by 2,6-lutidine (Lut), 2,2,6,6-tetramethylpiperidine (TMP), N-methyl-2,2,6,6-tetramethylpiperidine (MeTMP) and tri-tert-butylphosphine (TBP) with tris(pentafluorophenyl)borane (BCF). At 6.6 bar H2 the conversion of the Lewis acid Lewis base pair to the corresponding ionic pair in bromobenzene at 294 K was quantitative in under 60 minutes. Integration of the heat release from the reaction of the Frustrated Lewis Pair (FLP) with hydrogen as a function of time yields a relative rate of hydrogenation in addition to the enthalpy of hydrogenation. The half-lives of hydrogenation range from 230 seconds with TMP, ΔHH2 = -31.5(0.2)more » kcal/mol, to 1400 seconds with Lut, ΔHH2 = -23.4(0.4) kcal/mol. The 11B NMR spectrum of B(C6F5)3 in bromobenzene exhibits three distinct traits depending on the sterics of the Lewis base; (i) in the presence of pyridine, only the dative bond adduct pyridine--B(C6F5)3 is observed, (ii) in the presence of TMP and MeTMP only the free B(C6F5)3 is observed, and (iii) in the presence of Lut both the free B(C6F5)3 and the Lut--B(C6F5)3 adduct appear in equilibrium. A measure of the change in Keq of Lut + B(C6F5)3 <->Lut--B(C6F5)3 as a function of temperature provides thermodynamic properties of the Lewis acid Lewis base adduct, ΔH = -17.9(1.0) kcal/mol and a ΔS = -49.2(2.5) cal/mol K, suggesting the Lut--B(C6F5)3 adduct is more stable in bromobenzene than in toluene. This research was supported by the U.S. Department of Energy’s Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences. D.M.C. and A.K. acknowledges support by the Laboratory Directed Research and Development program at the Pacific Northwest National Laboratory (PNNL) to perform kinetic analyses of the calorimetry data. The work was performed in part at EMSL, a national scientific user facility sponsored by the DOE Office of Biological and Environmental Research. EMSL is located at Pacific Northwest National Laboratory (PNNL), which is operated by Battelle for DOE.« less

Optimal regimens of sulfamethoxazole-trimethoprim for chemoprophylaxis of Pneumocystis pneumonia in patients with systemic rheumatic diseases: results from a non-blinded, randomized controlled trial.

PubMed

Utsunomiya, Masako; Dobashi, Hiroaki; Odani, Toshio; Saito, Kazuyoshi; Yokogawa, Naoto; Nagasaka, Kenji; Takenaka, Kenchi; Soejima, Makoto; Sugihara, Takahiko; Hagiyama, Hiroyuki; Hirata, Shinya; Matsui, Kazuo; Nonomura, Yoshinori; Kondo, Masahiro; Suzuki, Fumihito; Tomita, Makoto; Kihara, Mari; Yokoyama, Waka; Hirano, Fumio; Yamazaki, Hayato; Sakai, Ryoko; Nanki, Toshihiro; Koike, Ryuji; Kohsaka, Hitoshi; Miyasaka, Nobuyuki; Harigai, Masayoshi

2017-01-18

Sulfamethoxazole-trimethoprim (SMX/TMP) is a standard drug for the prophylaxis of Pneumocystis pneumonia (PJP) in immunosuppressed patients with systemic rheumatic diseases, but is sometimes discontinued due to adverse events (AEs). The objective of this non-blinded, randomized, 52-week non-inferiority trial was to quest an effective chemoprophylaxis regimen for PJP with a low drug discontinuation rate. Results at week 24 were reported. Adult patients with systemic rheumatic diseases who started prednisolone ≥0.6 mg/kg/day were randomized into three dosage groups: a single-strength group (SS, SMX/TMP of 400/80 mg daily), half-strength group (HS, 200/40 mg daily), and escalation group (ES, started with 40/8 mg daily, increasing incrementally to 200/40 mg daily). The primary endpoint was non-incidence rates (non-IR) of PJP at week 24. Of 183 patients randomly allocated at a 1:1:1 ratio into the three groups, 58 patients in SS, 59 in HS, and 55 in ES started SMX/TMP. A total of 172 patients were included in the analysis. No cases of PJP were reported up to week 24. Estimated non-IR of PJP in patients who received daily SMX/TMP of 200/40 mg, either starting at this dose or increasing incrementally, was 96.8-100% using the exact confidence interval as a post-hoc analysis. The overall discontinuation rate was significantly lower with HS compared to SS (p = 0.007). The discontinuation rates due to AEs were significantly lower with HS (p = 0.006) and ES (p = 0.004) compared to SS. The IR of AEs requiring reduction in the dose of SMX/TMP (p = 0.009) and AEs of special interest (p = 0.003) were different among the three groups with significantly higher IR in SS compared to HS and ES. Although there were no PJP cases, the combined group of HS and ES had an excellent estimated non-IR of PJP and both were superior in safety to SS. From the perspective of feasibility and drug discontinuation rates, the daily half-strength regimen was suggested to be optimal for prophylaxis of PJP in patients with systemic rheumatic diseases. The University Hospital Medical Information Network Clinical Trials Registry number is UMIN000007727 , registered 10 April 2012.

Thermomechanical Transitions in Polyphosphazenes.

DTIC Science & Technology

1980-08-08

ADAOB8 119 PITTSBURGH UNIV PA DEPT OF METALLURGICAL AND MATERI --ETC F/6 11/9 THERMOMECHANICAL TRANSITIONS IN POLYPHOSPHAZENES.(U) AUG B0 I C CHOY, J...Metallurgical and Materials Engr._____ University of Pittsburgh METALLURGICAL AND MATERIALS ENGINEERING University of Pittsburgh Pittsburgh, Pennsylvania...15261 _ _ _ _ ,80 818 05, THERMOMECHANICAL TRANSITIONS IN POLYPHOSPHAZENES I. C. Choy and J. H. Magill Dept. of Metallurgical and Materials Engr

Thermo-mechanical analysis of an internal cooling system with various configurations of a combustion liner after shell

NASA Astrophysics Data System (ADS)

Moon, Hokyu; Kim, Kyung Min; Park, Jun Su; Kim, Beom Seok; Cho, Hyung Hee

2015-12-01

The after-shell section, which is part of the gas turbine combustion liner, is exposed to the hottest combustion gas. Various cooling schemes have been applied to protect against severe thermal load. However, there is a significant discrepancy in the thermal expansion with large temperature differences, resulting in thermo-mechanical crack formation. In this study, to reduce combustion liner damage, thermo-mechanical analysis was conducted on three after-shell section configurations: inline-discrete divider wall, staggered divider wall, and swirler wall arrays. These array components are well-known heat-transfer enhancement structures in the duct. In the numerical analyses, the heat transfer characteristics, temperature and thermo-mechanical stress distribution were evaluated using finite volume method and finite element method commercial codes. As a result, we demonstrated that the temperature and the thermo-mechanical stress distribution were readily dependent on the structural array for cooling effectiveness and structural support in each modified cooling system. Compared with the reference model, the swirler wall array was most effective in diminishing the thermo-mechanical stress concentration, especially on the inner ring that is vulnerable to crack formation.

Thermographic Assessment of the HAZ Properties and Structure of Thermomechanically Treated Steel

NASA Astrophysics Data System (ADS)

Górka, Jacek; Janicki, Damian; Fidali, Marek; Jamrozik, Wojciech

2017-12-01

Thermomechanically processed steels are materials of great mechanical properties connected with more than good weldability. This mixture makes them interesting for different types of industrial applications. When creating welded joints, a specified amount of heat is introduced into the welding area and a so called heat-affected zone (HAZ) is formed. The key issue is to reduce the width of the HAZ, because properties of the material in the HAZ are worse than in the base material. In the paper, thermographic measurements of HAZ temperatures were presented as a potential tool for quality assuring the welding process in terms of monitoring and control. The main issue solved was the precise temperature measurement in terms of varying emissivity during a welding thermal cycle. A model of emissivity changes was elaborated and successfully applied. Additionally, material in the HAZ was tested to reveal its properties and connect changes of those properties with heating parameters. The obtained results prove that correctly modeled emissivity allows measurement of temperature, which is a valuable tool for welding process monitoring.

Lower operational costs in heat treatment and process engineering through improved temperature measurement

NASA Astrophysics Data System (ADS)

Furniss, C. P.

New metal-sheathed thermocouple systems are described which have lowered operational heat treatment costs and process engineering. The improvements which these thermocouples represent over conventional ones with regard to chemical composition, thermomechanical properties, oxidation resistance, weldability, and coefficient of linear expansion are pointed out. Experimentally determined cost savings for a variety of applications are reported.

Effects of Deformation Texture Intensities and Precipitates on the Anisotropy of Mechanical Properties of Al-Li Alloy 2099 T83 Extrusions

NASA Astrophysics Data System (ADS)

Bois-Brochu, Alexandre; Blais, Carl; Goma, Franck Armel Tchitembo; Larouche, Daniel; Boselli, Julien; Brochu, Mathieu

The use of aluminum-lithium alloys in aerospace applications requires a thorough knowledge of how processing and product geometry impact their microstructure, texture and mechanical properties. As with other aluminum alloys, anisotropy of mechanical properties has been related to the formation of deformation textures during thermo-mechanical processes.

Papermaking properties of aspen ultrahigh-yield mechanical pulps

Treesearch

J. N. McGovern; T. H. Wegner

1991-01-01

Eleven types of aspen ultra-high-yield (90% and above) mechanical pubs were evaluated for their chemical compositions (including sulfur), handsheet strength, and optical properties, fiber length indices, and fiberizing energies. The pulping processes were stone groundwood, pressurized stone groundwood, refiner mechanical, thermomechanical, chemimechanical (alkaline...

Microstructural Evolution and the Precipitation Behavior in X90 Linepipe Steel During Isothermal Processing

NASA Astrophysics Data System (ADS)

Tian, Y.; Wang, H. T.; Wang, Z. D.; Misra, R. D. K.; Wang, G. D.

2018-03-01

Thermomechanical controlled processing of 560-MPa (X90) linepipe steel was simulated in the laboratory using a thermomechanical simulator to study the microstructural evolution and precipitation behavior during isothermal holding. The results indicated that martensite was obtained when the steels were isothermally held for 5 s at 700 °C. Subsequently, granular bainite and acicular ferrite transformation occurred with increased holding time. Different amount of polygonal ferrite formed after isothermally holding for 600-3600 s. Pearlite nucleated after isothermally holding for 3600 s. Precipitation occurred after isothermal holding for 5 s and continuous precipitation occurred at grain boundaries after isothermally holding for 600 s. After isothermally holding for 3600 s, large Nb/Ti carbide precipitated. The presence of MX-type precipitates was confirmed by diffraction pattern. The interphase precipitation (IP) occurred between 5 and 30 s. Maximum hardness was obtained after isothermally holding for 600 s when IP occurred and rapidly decreased to a low value, mainly because polygonal ferrite dominated the microstructure after isothermally holding for 3600 s.

Deformation and annealing study of Nicraly

NASA Technical Reports Server (NTRS)

Trela, D. M.; Ebert, L. J.

1975-01-01

Extensive experiments were carried out on the ODS alloy Nicraly, (an alloy prepared by mechanical alloying and consolidating a powder blend consisting of 16% chromium, 4% aluminum, 2-3% yttria, balance nickel), in efforts to develop methods of controlling the grain size and grain shape of the material. The experiments fell into two general categories: variations in the annealing parameters using the as-extruded material as it was received, and various thermomechanical processing schedules (various combinations of cold work and annealing). Success was achieved in gaining grain size and grain shape control by annealing of the as-extruded material. By proper selection of annealing temperature and cooling rates, the grain size of the as-received material was increased almost two orders of magnitude (from an average grain dimension of 0.023 mm to 1.668 mm) while the aspect ratio was increased by some 50% (from 20:1 to 30:1). No success was achieved in gaining significant control of the grain size and shape of the material by thermo-mechanical processing.

Thermo-mechanical Processing of TRIP-Aided Steels

NASA Astrophysics Data System (ADS)

Ranjan, Ravi; Beladi, Hossein; Singh, Shiv Brat; Hodgson, Peter D.

2015-07-01

The effects of the partial replacement of Si with Al and the addition of P on the microstructure and mechanical properties of experimental TRIP-aided steels subjected to different thermo-mechanical cycles were studied. Based on the available literature and thermodynamics-based calculations, three steels with different compositions were designed to obtain optimum results from a relatively low number of experiments. Different combinations of microstructure were developed through three different kinds of thermo-mechanical-controlled processing (TMCP) routes, and the corresponding tensile properties were evaluated. The results indicated that partial replacement of Si with Al improved the strength-ductility balance along with providing an improved variation in the incremental change in the strain-hardening exponent. However, the impact of the P addition was found to depend more on the final microstructure obtained by the different TMCP cycles. It has also been shown that an increase in the volume fraction of the retained austenite () or its carbon content () resulted in an improved strength-ductility balance, which can be attributed to better exploitation of the TRIP effect.

Development of Semantic Description for Multiscale Models of Thermo-Mechanical Treatment of Metal Alloys

NASA Astrophysics Data System (ADS)

Macioł, Piotr; Regulski, Krzysztof

2016-08-01

We present a process of semantic meta-model development for data management in an adaptable multiscale modeling framework. The main problems in ontology design are discussed, and a solution achieved as a result of the research is presented. The main concepts concerning the application and data management background for multiscale modeling were derived from the AM3 approach—object-oriented Agile multiscale modeling methodology. The ontological description of multiscale models enables validation of semantic correctness of data interchange between submodels. We also present a possibility of using the ontological model as a supervisor in conjunction with a multiscale model controller and a knowledge base system. Multiscale modeling formal ontology (MMFO), designed for describing multiscale models' data and structures, is presented. A need for applying meta-ontology in the MMFO development process is discussed. Examples of MMFO application in describing thermo-mechanical treatment of metal alloys are discussed. Present and future applications of MMFO are described.

Study on the extrusion of nickel-based spark plug electrodes by numerical simulation

NASA Astrophysics Data System (ADS)

Saby, Q.; Courbon, C.; Salvatore, F.; Fabre, D.; Romeyer, F.

2018-05-01

Interest in metal forming simulation has grown rapidly during the last decades and is now well established even in industry. It provides a flexible and relatively cheap method to perform sensitivity analyses, getting a better insight into the forming process and use it as an optimisation tool. As far as wear is concerned, numerical simulation can be seen as a relevant approach to assess the thermomechanical loadings applied to the active die surface and therefore predict their wear behaviour. In this study, a Finite-Element (FE) based model has been developed in order to investigate the cold forming process of a nickel-based sparkplug electrode. A fully thermo-mechanically coupled implicit formulation has been used in order to model the forward extrusion step with a special emphasis on the contact conditions at the workpiece-die interface. Contact pressure, relative sliding velocity and temperature profiles have been extracted versus time and qualitatively compared to the wear phenomena observed on the worn production dies.

Strengthening Mechanisms in Thermomechanically Processed NbTi-Microalloyed Steel

NASA Astrophysics Data System (ADS)

Kostryzhev, Andrii G.; Marenych, Olexandra O.; Killmore, Chris R.; Pereloma, Elena V.

2015-08-01

The effect of deformation temperature on microstructure and mechanical properties was investigated for thermomechanically processed NbTi-microalloyed steel with ferrite-pearlite microstructure. With a decrease in the finish deformation temperature at 1348 K to 1098 K (1075 °C to 825 °C) temperature range, the ambient temperature yield stress did not vary significantly, work hardening rate decreased, ultimate tensile strength decreased, and elongation to failure increased. These variations in mechanical properties were correlated to the variations in microstructural parameters (such as ferrite grain size, solid solution concentrations, precipitate number density and dislocation density). Calculations based on the measured microstructural parameters suggested the grain refinement, solid solution strengthening, precipitation strengthening, and work hardening contributed up to 32 pct, up to 48 pct, up to 25 pct, and less than 3 pct to the yield stress, respectively. With a decrease in the finish deformation temperature, both the grain size strengthening and solid solution strengthening increased, the precipitation strengthening decreased, and the work hardening contribution did not vary significantly.

Fabrication of stable electrode/diffusion barrier layers for thermoelectric filled skutterudite devices

DOEpatents

Jie, Qing; Ren, Zhifeng; Chen, Gang

2015-12-08

Disclosed are methods for the manufacture of n-type and p-type filled skutterudite thermoelectric legs of an electrical contact. A first material of CoSi.sub.2 and a dopant are ball-milled to form a first powder which is thermo-mechanically processed with a second powder of n-type skutterudite to form a n-type skutterudite layer disposed between a first layer and a third layer of the doped-CoSi.sub.2. In addition, a plurality of components such as iron, and nickel, and at least one of cobalt or chromium are ball-milled form a first powder that is thermo-mechanically processed with a p-type skutterudite layer to form a p-type skutterudite layer "second layer" disposed between a first and a third layer of the first powder. The specific contact resistance between the first layer and the skutterudite layer for both the n-type and the p-type skutterudites subsequent to hot-pressing is less than about 10.0 .mu..OMEGA.cm.sup.2.

Fabrication of stable electrode/diffusion barrier layers for thermoelectric filled skutterudite devices

DOEpatents

Jie, Qing; Ren, Zhifeng; Chen, Gang

2017-08-01

Disclosed are methods for the manufacture of n-type and p-type filled skutterudite thermoelectric legs of an electrical contact. A first material of CoSi.sub.2 and a dopant are ball-milled to form a first powder which is thermo-mechanically processed with a second powder of n-type skutterudite to form a n-type skutterudite layer disposed between a first layer and a third layer of the doped-CoSi.sub.2. In addition, a plurality of components such as iron, and nickel, and at least one of cobalt or chromium are ball-milled form a first powder that is thermo-mechanically processed with a p-type skutterudite layer to form a p-type skutterudite layer "second layer" disposed between a first and a third layer of the first powder. The specific contact resistance between the first layer and the skutterudite layer for both the n-type and the p-type skutterudites subsequent to hot-pressing is less than about 10.0 .mu..OMEGA.cm.sup.2.

Effect of deformation schedule on the microstructure and mechanical properties of a thermomechanically processed C-Mn-Si transformation-induced plasticity steel

NASA Astrophysics Data System (ADS)

Timokhina, I. B.; Hodgson, P. D.; Pereloma, E. V.

2003-08-01

Thermomechanical processing simulations were performed using a hot-torsion machine, in order to develop a comprehensive understanding of the effect of severe deformation in the recrystallized and nonrecrystallized austenite regions on the microstructural evolution and mechanical properties of the 0.2 wt pct C-1.55 wt pct Mn-1.5 wt pct Si transformation-induced plasticity (TRIP) steel. The deformation schedule affected all constituents (polygonal ferrite, bainite in different morphologies, retained austenite, and martensite) of the multiphased TRIP steel microstructure. The complex relationships between the volume fraction of the retained austenite, the morphology and distribution of all phases present in the microstructure, and the mechanical properties of TRIP steel were revealed. The bainite morphology had a more pronounced effect on the mechanical behavior than the refinement of the microstructure. The improvement of the mechanical properties of TRIP steel was achieved by variation of the volume fraction of the retained austenite rather than the overall refinement of the microstructure.

Effects of thermomechanical processing on the microstructure and mechanical properties of a Ti-V-N steel

NASA Astrophysics Data System (ADS)

Dogan, B.; Collins, L. E.; Boyd, J. D.

1988-05-01

Based on studies of austenite deformation behavior and continuous-cooling-transformation behavior of a Ti-V microalloyed steel by cam plastometer and quench-deformation dilatometer, respectively, plate rolling schedules were designed to produce (i) recrystallized austenite, (ii) unrecrystallized austenite, (iii) deformed ferrite + unrecrystallized austenite. The effects of austenite condition and cooling rate on the final microstructure and mechanical properties were investigated. To rationalize the variation in final ferrite grain size with different thermomechanical processing schedules, it is necessary to consider the kinetics of ferrite grain growth in addition to the density of ferrite nucleation sites. The benefit of dilatometer studies in determining the optimum deformation schedule and cooling rate for a given steel is domonstrated. A wide range of tensile and impact properties results from the different microstructures studied. Yield strength is increased by increasing the amount of deformed ferrite, bainite, or martensite, and by decreasing the ferrite grain size. Impact toughness is most strongly influenced by ferrite grain size and occurrence of rolling plane delaminations.

Resource for structure related information on transmembrane proteins

NASA Astrophysics Data System (ADS)

Tusnády, Gábor E.; Simon, István

Transmembrane proteins are involved in a wide variety of vital biological processes including transport of water-soluble molecules, flow of information and energy production. Despite significant efforts to determine the structures of these proteins, only a few thousand solved structures are known so far. Here, we review the various resources for structure-related information on these types of proteins ranging from the 3D structure to the topology and from the up-to-date databases to the various Internet sites and servers dealing with structure prediction and structure analysis. Abbreviations: 3D, three dimensional; PDB, Protein Data Bank; TMP, transmembrane protein.

The investigation of the influence of thermomechanical treatment of the material of rotary cutter bit toolholders on its hardness

NASA Astrophysics Data System (ADS)

Chupin, S. A.; Bolobov, V. I.

2017-02-01

The causes of failure of the tangential rotary cutter bits of the road header during stonedrift in rocks of medium strength are analyzed in the article. It was revealed that the most typical cause of failure of cutter bits is premature wear of the toolholder (body) of the cutter bit. It is well known that the most effective way to improve the wear resistance is to increase hardness. The influence of the thermomechanical treatment of the material of the cutter bit toolholder on its hardness is studied. It was established that the thermomechanical treatment of the cutter bit toolholder material results in the increase of its hardness. It was found that the increase of material hardness is proportional to the increase of material strain intensity during thermomechanical treatment. It was concluded that the use of thermomechanical treatment can lead to the increase of both the hardness and wear resistance of the cutter bit material.

Effect of Nb2O5 doping on improving the thermo-mechanical stability of sealing interfaces for solid oxide fuel cells.

PubMed

Zhang, Qi; Du, Xinhang; Tan, Shengwei; Tang, Dian; Chen, Kongfa; Zhang, Teng

2017-07-13

Nb 2 O 5 is added to a borosilicate sealing system to improve the thermo-mechanical stability of the sealing interface between the glass and Fe-Cr metallic interconnect (Crofer 22APU) in solid oxide fuel cells (SOFCs). The thermo-mechanical stability of the glass/metal interface is evaluated experimentally as well as by using a finite element analysis (FEA) method. The sealing glass doped with 4 mol.% Nb 2 O 5 shows the best thermo-mechanical stability, and the sealing couple of Crofer 22APU/glass/GDC (Gd 0.2 Ce 0.8 O 1.9 ) remains intact after 50 thermal cycles. In addition, all sealing couples show good joining after being held at 750 °C for 1000 h. Moreover, the possible mechanism on the thermo-mechanical stability of sealing interface is investigated in terms of stress-based and energy-based perspectives.

A thermomechanical constitutive model for cemented granular materials with quantifiable internal variables. Part I-Theory

NASA Astrophysics Data System (ADS)

Tengattini, Alessandro; Das, Arghya; Nguyen, Giang D.; Viggiani, Gioacchino; Hall, Stephen A.; Einav, Itai

2014-10-01

This is the first of two papers introducing a novel thermomechanical continuum constitutive model for cemented granular materials. Here, we establish the theoretical foundations of the model, and highlight its novelties. At the limit of no cement, the model is fully consistent with the original Breakage Mechanics model. An essential ingredient of the model is the use of measurable and micro-mechanics based internal variables, describing the evolution of the dominant inelastic processes. This imposes a link between the macroscopic mechanical behavior and the statistically averaged evolution of the microstructure. As a consequence this model requires only a few physically identifiable parameters, including those of the original breakage model and new ones describing the cement: its volume fraction, its critical damage energy and bulk stiffness, and the cohesion.

Effects of Palladium Content, Quaternary Alloying, and Thermomechanical Processing on the Behavior of Ni-Ti-Pd Shape Memory Alloys for Actuator Applications

NASA Technical Reports Server (NTRS)

Bigelow, Glen

2008-01-01

The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently driving research in high-temperature shape memory alloys (HTSMA) having transformation temperatures above 100 C. One of the basic high temperature systems under investigation to fill this need is NiTiPd. Prior work on this alloy system has focused on phase transformations and respective temperatures, no-load shape memory behavior (strain recovery), and tensile behavior for selected alloys. In addition, a few tests have been done to determine the effect of boron additions and thermomechanical treatment on the aforementioned properties. The main properties that affect the performance of a solid state actuator, namely work output, transformation strain, and permanent deformation during thermal cycling under load have mainly been neglected. There is also no consistent data representing the mechanical behavior of this alloy system over a broad range of compositions. For this thesis, ternary NiTiPd alloys containing 15 to 46 at.% palladium were processed and the transformation temperatures, basic tensile properties, and work characteristics determined. However, testing reveals that at higher levels of alloying addition, the benefit of increased transformation temperature begins to be offset by lowered work output and permanent deformation or "walking" of the alloy during thermal cycling under load. In response to this dilemma, NiTiPd alloys have been further alloyed with gold, platinum, and hafnium additions to solid solution strengthen the martensite and parent austenite phases in order to improve the thermomechanical behavior of these materials. The tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared and discussed. In addition, the benefits of more advanced thermomechanical processing or training on the dimensional stability of these alloys during repeated actuation were investigated. Finally, the effect of quaternary alloying on the thermal stability of NiTiPdX alloys is determined via thermal cycling of the materials to increasing temperatures under load. It was found that solid solution additions of platinum and gold resulted in about a 30 C increase in upper use temperature compared to the baseline NiTiPd alloy, providing an added measure of over-temperature protection.

Thermomechanical properties of polymeric materials and related stresses

NASA Technical Reports Server (NTRS)

Lee, Sheng Yen

1990-01-01

The thermomechanical properties of a number of widely used polymeric materials were determined by thermomechanical analysis and dynamic mechanical analysis. A combined profile of the coefficient of thermal expansion and the modulus change over a wide temperature range obtained by the analyses shows clearly the drastic effect of the glass transition on both the CTE and the modulus of a polymer, and the damaging potential due to such effect.

A drive based on an element made of a thermomechanical memory material

NASA Astrophysics Data System (ADS)

Krakhin, O. I.; Dubovik, I. N.; Rozarenova, Iu. A.

The advantages of using drives with active elements made of thermomechanical memory materials in aircraft structures are briefly reviewed. The choice of a particular type of active element based on a thermomechanical memory material is shown to depend on the specific operating conditions of the drive. The design of a rotary drive with an active element of TN-1 alloy is examined as an example.

40 CFR 430.77 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... are produced through the application of the thermo-mechanical process] Pollutant or pollutant property...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp Subcategory § 430.77 Pretreatment standards for new sources (PSNS). (a) The following applies to mechanical...

40 CFR 430.75 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... thermo-mechanical process] Pollutant or pollutant property Kg/kkg (or pounds per 1,000 lb) ofproduct... GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp Subcategory § 430.75 New source performance standards (NSPS). (a) The following applies to mechanical pulp...

40 CFR 430.76 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2011 CFR

2011-07-01

... through the application of the thermo-mechanical process] Pollutant or pollutant property Maximum for any...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of...

40 CFR 430.77 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp Subcategory § 430.77 Pretreatment standards for new sources (PSNS). (a) The following applies to mechanical... thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and coarse...

40 CFR 430.76 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

Potential applications for amylose inclusion complexes produced by steam jet cooking

USDA-ARS?s Scientific Manuscript database

Steam jet cooking is a commercially scalable method of thermomechanically processing starch for many applications. Previous studies at NCAUR have revealed the specific effects of heat and shear on various starch types cooked under different steam flow, pressure, and slurry flow conditions. Starch-...

On the effect of incremental forming on alpha phase precipitation and mechanical behavior of beta-Ti-10V-2Fe-3Al

NASA Astrophysics Data System (ADS)

Winter, S.; F-X Wagner, M.

2016-03-01

A combination of good ductility and fatigue resistance makes β-titanium alloys interesting for many current and potential future applications. The mechanical behavior is primarily determined by microstructural parameters like (beta phase) grain size, morphology and volume fraction of primary / secondary α-phase precipitates, and this allows changing and optimizing their mechanical properties across a wide range. In this study, we investigate the possibility to modify the microstructure of the high-strength beta titanium alloy Ti-10V-2Fe-3Al, with a special focus on shape and volume fraction of primary α-phase. In addition to the conventional strategy for precipitation of primary α, a special thermo-mechanical processing is performed; this processing route combines the conventional heat treatment with incremental forming during the primary α-phase annealing. After incremental forming, considerable variations in terms of microstructure and mechanical properties can be obtained for different thermo-mechanical processing routes. The microstructures of the deformed samples are characterized by globular as well as lamellar (bimodal) α precipitates, whereas conventional annealing only results in the formation of lamellar precipitates. Because of the smaller size, and the lower amount, of α-phase after incremental forming, tensile strength is not as high as after the conventional strategy. However, high amounts of grain boundary α and lamellar αp-phase in the undeformed samples lead to a significantly lower ductility in comparison to the matrix with bimodal structures obtained by thermo-mechanical processing. These results illustrate the potential of incremental forming during the annealing to modify the microstructure of the beta titanium Ti-10V-2Fe-3Al in a wide range of volume fractions and morphologies of the primary α phase, which in turn leads to considerably changes, and improved, mechanical properties.

Mechanisms of postseismic relaxation after a great subduction earthquake constrained by cross-scale thermomechanical model and geodetic observations

NASA Astrophysics Data System (ADS)

Sobolev, Stephan; Muldashev, Iskander

2016-04-01

According to conventional view, postseismic relaxation process after a great megathrust earthquake is dominated by fault-controlled afterslip during first few months to year, and later by visco-elastic relaxation in mantle wedge. We test this idea by cross-scale thermomechanical models of seismic cycle that employs elasticity, mineral-physics constrained non-linear transient viscous rheology and rate-and-state friction plasticity. As initial conditions for the models we use thermomechanical models of subduction zones at geological time-scale including a narrow subduction channel with low static friction for two settings, similar to the Southern Chile in the region of the great Chile Earthquake of 1960 and Japan in the region of Tohoku Earthquake of 2011. We next introduce in the same models classic rate-and state friction law in subduction channels, leading to stick-slip instability. The models start to generate spontaneous earthquake sequences and model parameters are set to closely replicate co-seismic deformations of Chile and Japan earthquakes. In order to follow in details deformation process during the entire seismic cycle and multiple seismic cycles we use adaptive time-step algorithm changing integration step from 40 sec during the earthquake to minute-5 year during postseismic and interseismic processes. We show that for the case of the Chile earthquake visco-elastic relaxation in the mantle wedge becomes dominant relaxation process already since 1 hour after the earthquake, while for the smaller Tohoku earthquake this happens some days after the earthquake. We also show that our model for Tohoku earthquake is consistent with the geodetic observations for the day-to-4year time range. We will demonstrate and discuss modeled deformation patterns during seismic cycles and identify the regions where the effects of afterslip and visco-elastic relaxation can be best distinguished.

Density functional theory mechanistic study of the reduction of CO2 to CH4 catalyzed by an ammonium hydridoborate ion pair: CO2 activation via formation of a formic acid entity.

PubMed

Wen, Mingwei; Huang, Fang; Lu, Gang; Wang, Zhi-Xiang

2013-10-21

Density functional theory computations have been applied to gain insight into the CO2 reduction to CH4 with Et3SiH, catalyzed by ammonium hydridoborate 1 ([TMPH](+)[HB(C6F5)3](-), where TMP = 2,2,6,6-tetramethylpiperidine) and B(C6F5)3. The study shows that CO2 is activated through the concerted transfer of H(δ+) and H(δ-) of 1 to CO2, giving a complex (IM2) with a well-formed HCOOH entity, followed by breaking of the O-H bond of the HCOOH entity to return H(δ+) to TMP, resulting in an intermediate 2 ([TMPH](+)[HC(═O)OB(C6F5)3)](-)), with CO2 being inserted into the B-H bond of 1. However, unlike CO2 insertion into transition-metal hydrides, the direct insertion of CO2 into the B-H bond of 1 is inoperative. The computed CO2 activation mechanism agrees with the experimental synthesis of 2 via reacting HCOOH with TMP/B(C6F5)3. Subsequent to the CO2 activation and B(C6F5)3-mediated hydrosilylation of 2 to regenerate the catalyst (1), giving HC(═O)OSiEt3 (5), three hydride-transfer steps take place, sequentially transferring H(δ-) of Et3SiH to 5 to (Et3SiO)2CH2 (6, the product of the first hydride-transfer step) to Et3SiOCH3 (7, the product of the second hydride-transfer step) and finally resulting in CH4. These hydride transfers are mediated by B(C6F5)3 via two SN2 processes without involving 1. B(C6F5)3 acts as a hydride carrier that, with the assistance of a nucleophilic attack of 5-7, first grabs H(δ-) from Et3SiH (the first SN2 process), giving HB(C6F5)3(-), and then leave H(δ-) of HB(C6F5)3(-) to the electrophilic C center of 5-7 (the second SN2 process). The SN2 processes utilize the electrophilic and nucleophilic characteristics possessed by the hydride acceptors (5-7). The hydride-transfer mechanism is different from that in the CO2 reduction to methanol catalyzed by N-heterocyclic carbene (NHC) and PCP-pincer nickel hydride ([Ni]H), where the characteristic of possessing a C═O double bond of the hydride acceptors is utilized for hydride transfer. The mechanistic differences elucidate why the present system can completely reduce CO2 to CH4, whereas NHC and [Ni]H catalysts can only mediate the reduction of CO2 to [Si]OCH3 and catBOCH3, respectively. Understanding this could help in the development of catalysts for selective CO2 reduction to CH4 or methanol.

Structural characterization and in vitro antitumor activity of a novel polysaccharide from Taxus yunnanensis.

PubMed

Yan, Chunyan; Yin, Yin; Zhang, Dawei; Yang, Wei; Yu, Rongmin

2013-07-25

The shrub, Taxus yunnanensis is famed as the source of the important anticancer drug, paclitaxel. But research on its polysaccharides contents has been scarce. The present research aimed to investigate the polysaccharide content of T. yunnanensis leaves and study the antitumor activities of isolated polysaccharide(s) using human tumor cells (K-562 and MCF). A novel heteropolysaccharide (TMP70W) was isolated and purified by anion-exchange and gel-permeation chromatography. Its molecular weight was 36.94 kDa and structural features were elucidated by partial acid hydrolysis, periodate oxidation-Smith degradation, methylation analysis, GC-MS, HPAEC-PAD, FT-IR, and NMR. The repeating unit of TMP70W had a backbone composed of (1→5)-linked-α-l-Araf, (1→2,5)-linked-α-l-Araf, and (1→6)-linked-β-d-Galp with a branch of α-d-Glcp-(1→2)-α-d-Galp-(1→ at the position of C-2 of arabinose. TMP70W displayed mild cytotoxicity against K562 cells with the IC50 value of 39.63 ± 2.37 μg/mL and inhibitory activity against MCF-7 cells (32.08 ± 0.39% at the concentration of 400 μg/mL) in a concentration-dependent manner. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterization of Streptococcus pneumoniae thymidylate kinase: steady-state kinetics of the forward reaction and isothermal titration calorimetry.

PubMed Central

Petit, Chantal M; Koretke, Kristin K

2002-01-01

Thymidylate kinase (TMK) catalyses the phosphorylation of dTMP to form dTDP in both the de novo and salvage pathways of dTTP synthesis. The tmk gene from the bacterial pathogen Streptococcus pneumoniae was identified. The gene, encoding a 212-amino-acid polypeptide (23352 Da), was cloned and overexpressed in Escherichia coli with an N-terminal hexahistidine tag. The enzyme was purified to homogeneity, and characterized in the forward reaction. The pH profile of TMK indicates that its activity is optimal at pH 8.5. The substrate specificity of the enzyme was examined; it was found that not only ATP, but also dATP and to a lesser extent CTP, could act as phosphate donors, and dTMP and dUMP could serve as phosphate acceptors. Furthermore, AZT-MP (3'-azido-3'-deoxythymidine 5'-monophosphate) was shown not to be a substrate for S. pneumoniae TMK. Steady-state kinetics and inhibition studies with adenosine 5'-[beta-thio]diphosphate and dTDP in addition to isothermal titration calorimetry were performed. The data showed that binding follows an ordered pathway, in which ATP binds first with a K(m) of 235 +/- 46 microM and a K(d) of 116 +/- 3 microM, and dTMP binds secondly with a K(m) of 66 +/- 12 microM and a K(d) of 53 +/- 2 microM. PMID:11964185

TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE AND FOSFOMYCIN SUSCEPTIBILITY RATES IN UNCOMPLICATED URINARY TRACT INFECTIONS: TIME TO CHANGE THE ANTIMICROBIAL PREFERENCES.

PubMed

Guneysel, Ozlem; Suman, Enes; Ozturk, Tuba Cimilli

2016-03-01

Urinary tract infections (UTIs) are among the most common bacterial infections in adult population. They are prevalent in all age groups both in women and men. Also, UTIs are the most frequent indication for empirical antibiotic treatment in emergency department. The aim of this study was to determine the antibiotic resistance rates in the treatment of uncomplicated UTIs. Adult patients admitted to emergency department with uncomplicated UTIs were included in this cross-sectional study. Mid-stream urine samples were obtained under sterile conditions and cultured quantitatively. After 24 hours, the samples showing 10(5) colony forming unit per milliliter (CFU/mL) were tested for antibiotic susceptibility. Resistance to fosfomycin-trometamol (FT), amoxicillin-clavulanic acid (AC), ciprofloxacin (CIP), trimethoprim-sulfamethoxazole (TMP-SMX) and cefpodoxime (CEF) was tested by Kirby-Bauer disc diffusion system. Escherichia (E.) coli accounted for the vast majority (93.4%) of the organisms isolated in the study. Among the E. coli positive patients, resistance to TMP-SMX was the most common antibiotic resistance. The E. coli species detected in our study group were least resistant to FT (2.4%). The resistance rates, especially to CEF, AC and CIP, were significantly higher in patients over 50 years of age. In conclusion, in the treatment of uncomplicated UTIs, TMP-SMX should be excluded from empirical treatment, while fosfomycin could be a viable option in all age groups.

Inverse Electrocardiographic Source Localization of Ischemia: An Optimization Framework and Finite Element Solution

PubMed Central

Wang, Dafang; Kirby, Robert M.; MacLeod, Rob S.; Johnson, Chris R.

2013-01-01

With the goal of non-invasively localizing cardiac ischemic disease using body-surface potential recordings, we attempted to reconstruct the transmembrane potential (TMP) throughout the myocardium with the bidomain heart model. The task is an inverse source problem governed by partial differential equations (PDE). Our main contribution is solving the inverse problem within a PDE-constrained optimization framework that enables various physically-based constraints in both equality and inequality forms. We formulated the optimality conditions rigorously in the continuum before deriving finite element discretization, thereby making the optimization independent of discretization choice. Such a formulation was derived for the L2-norm Tikhonov regularization and the total variation minimization. The subsequent numerical optimization was fulfilled by a primal-dual interior-point method tailored to our problem’s specific structure. Our simulations used realistic, fiber-included heart models consisting of up to 18,000 nodes, much finer than any inverse models previously reported. With synthetic ischemia data we localized ischemic regions with roughly a 10% false-negative rate or a 20% false-positive rate under conditions up to 5% input noise. With ischemia data measured from animal experiments, we reconstructed TMPs with roughly 0.9 correlation with the ground truth. While precisely estimating the TMP in general cases remains an open problem, our study shows the feasibility of reconstructing TMP during the ST interval as a means of ischemia localization. PMID:23913980

Comparative study on the treatment of raw and biologically treated textile effluents through submerged nanofiltration.

PubMed

Chen, Qing; Yang, Ying; Zhou, Mengsi; Liu, Meihong; Yu, Sanchuan; Gao, Congjie

2015-03-02

Raw and biologically treated textile effluents were submerged filtrated using lab-fabricated hollow fiber nanofiltration membrane with a molecular weight cut-off of about 650 g/mol. Permeate flux, chemical oxygen demand (COD) reduction, color removal, membrane fouling, and cleaning were investigated and compared by varying the trans-membrane pressure (TMP) and volume concentrating factor (VCF). It was found that both raw and biologically treated textile effluents could be efficiently treated through submerged nanofiltration. The increase of TMP resulted in a decline in water permeability, COD reduction, color removal, and flux recovery ratio, while the increase of VCF resulted in both increased COD reduction and color removal. Under the TMP of 0.4 bar and VCF of 5.0, fluxes of 1.96 and 2.59 l/m(2)h, COD reductions of 95.7 and 94.2%, color removals of 99.0, and 97.3% and flux recovery ratios of 91.1 and 92.9% could be obtained in filtration of raw and biologically treated effluents, respectively. After filtration, the COD and color contents of the raw effluent declined sharply from 1780 to 325 mg/l and 1.200 to 0.060 Abs/cm, respectively, while for the biologically treated effluent, they decreased from 780 to 180 mg/l and 0.370 to 0.045 Abs/cm, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

The role of CD4 cell count as discriminatory measure to guide chemoprophylaxis against Pneumocystis jirovecii pneumonia in human immunodeficiency virus-negative immunocompromised patients: A systematic review.

PubMed

Messiaen, Peter E; Cuyx, Senne; Dejagere, Tom; van der Hilst, Jeroen C

2017-04-01

In recent years, the incidence of Pneumocystis jirovecii pneumonia (PJP) has increased in immunocompromised patients without human immunodeficiency virus (HIV) infection. Chemoprophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) is highly effective in preventing PJP in both HIV-positive and -seronegative patients. In HIV-positive patients, the risk of PJP is strongly correlated with decreased CD4 cell count. The role of CD4 cell count in the pathogenesis of PJP in non-HIV immunocompromised patients is less well studied. For most immunosuppressive conditions, no clear guidelines indicate whether to start TMP-SMX. We conducted a systematic literature review with the aim to provide a comprehensive overview on the role of CD4 cell counts in managing the risk of PJP in HIV-seronegative patients. Of the 63 individual studies retrieved, 14 studies report on CD4 cell counts in a variety of immunosuppressive conditions. CD4 cell count were <200/μL in 73.1% of the patients. CD4 cell count <200/μL is a sensitive biomarker to identify non-HIV immunocompromised patients who are at risk for PJP. Measuring CD4 cell counts could help clinicians identify patients who may benefit from TMP-SMX prophylaxis. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Succession of biofilm communities responsible for biofouling of membrane bio-reactors (MBRs)

PubMed Central

Luo, Jinxue; Lv, Pengyi; Zhang, Jinsong; Fane, Anthony G.; McDougald, Diane

2017-01-01

Biofilm formation is one of the main factors associated with membrane biofouling in membrane bioreactors (MBRs). As such, it is important to identify the responsible organisms to develop targeted strategies to control biofouling. This study investigated the composition and changes in the microbial communities fouling MBR membranes over time and correlated those changes with an increase in transmembrane pressure (TMP). Based on qPCR data, bacteria were the dominant taxa of the biofilm (92.9–98.4%) relative to fungi (1.5–6.9%) and archaea (0.03–0.07%). NMDS analysis indicated that during the initial stages of operation, the biofilm communities were indistinguishable from those found in the sludge. However, the biofilm community significantly diverged from the sludge over time and ultimately showed a unique biofilm profile. This suggested that there was strong selection for a group of organisms that were biofilm specialists. This pattern of succession and selection was correlated with the rapid increase in TMP, where bacteria including Rhodospirillales, Sphingomonadales and Rhizobiales dominated the biofilm at this time. While most of the identified fungal OTUs matched Candida sp., the majority of fungal communities were unclassified by 18S rRNA gene sequencing. Collectively, the data suggests that bacteria, primarily, along with fungi may play an important role in the rapid TMP increase and loss of system performance. PMID:28686622

GaN-on-diamond electronic device reliability: Mechanical and thermo-mechanical integrity

NASA Astrophysics Data System (ADS)

Liu, Dong; Sun, Huarui; Pomeroy, James W.; Francis, Daniel; Faili, Firooz; Twitchen, Daniel J.; Kuball, Martin

2015-12-01

The mechanical and thermo-mechanical integrity of GaN-on-diamond wafers used for ultra-high power microwave electronic devices was studied using a micro-pillar based in situ mechanical testing approach combined with an optical investigation of the stress and heat transfer across interfaces. We find the GaN/diamond interface to be thermo-mechanically stable, illustrating the potential for this material for reliable GaN electronic devices.

Regional-scale geomechanical impact assessment of underground coal gasification by coupled 3D thermo-mechanical modeling

NASA Astrophysics Data System (ADS)

Otto, Christopher; Kempka, Thomas; Kapusta, Krzysztof; Stańczyk, Krzysztof

2016-04-01

Underground coal gasification (UCG) has the potential to increase the world-wide coal reserves by utilization of coal deposits not mineable by conventional methods. The UCG process involves combusting coal in situ to produce a high-calorific synthesis gas, which can be applied for electricity generation or chemical feedstock production. Apart from its high economic potentials, UCG may induce site-specific environmental impacts such as fault reactivation, induced seismicity and ground subsidence, potentially inducing groundwater pollution. Changes overburden hydraulic conductivity resulting from thermo-mechanical effects may introduce migration pathways for UCG contaminants. Due to the financial efforts associated with UCG field trials, numerical modeling has been an important methodology to study coupled processes considering UCG performance. Almost all previous UCG studies applied 1D or 2D models for that purpose, that do not allow to predict the performance of a commercial-scale UCG operation. Considering our previous findings, demonstrating that far-field models can be run at a higher computational efficiency by using temperature-independent thermo-mechanical parameters, representative coupled simulations based on complex 3D regional-scale models were employed in the present study. For that purpose, a coupled thermo-mechanical 3D model has been developed to investigate the environmental impacts of UCG based on a regional-scale of the Polish Wieczorek mine located in the Upper Silesian Coal Basin. The model size is 10 km × 10 km × 5 km with ten dipping lithological layers, a double fault and 25 UCG reactors. Six different numerical simulation scenarios were investigated, considering the transpressive stress regime present in that part of the Upper Silesian Coal Basin. Our simulation results demonstrate that the minimum distance between the UCG reactors is about the six-fold of the coal seam thickness to avoid hydraulic communication between the single UCG reactors. Fault reactivation resulting from fault shear and normal displacements is discussed under consideration of potentially induced seismicity. Here, the coupled simulation results indicate that seismic hazard during UCG operation remains negligible with a seismic moment magnitude of MW < 3.

Mechanical Alloying for Making Thermoelectric Compounds

NASA Technical Reports Server (NTRS)

Huang, Chen-Kuo; Fleurial, Jean-Pierre; Snyder, Jeffrey; Blair, Richard; May, Andrew

2007-01-01

An economical room-temperature mechanical alloying process has been shown to be an effective means of making a homogeneous powder that can be hot-pressed to synthesize a thermoelectric material having reproducible chemical composition. The synthesis of a given material consists of the room temperature thermomechanical-alloying process followed b y a hot-pressing process. Relative to synthesis of nominally the same material by a traditional process that includes hot melting, this s ynthesis is simpler and yields a material having superior thermoelect ric properties.

Current challenges and concepts of the thermomechanical treatment of nickel-titanium instruments.

PubMed

Shen, Ya; Zhou, Hui-min; Zheng, Yu-feng; Peng, Bin; Haapasalo, Markus

2013-02-01

The performance and mechanical properties of nickel-titanium (NiTi) instruments are influenced by factors such as cross-section, flute design, raw material, and manufacturing processes. Many improvements have been proposed by manufacturers during the past decade to provide clinicians with safer and more efficient instruments. The mechanical performance of NiTi alloys is sensitive to their microstructure and associated thermomechanical treatment history. Heat treatment or thermal processing is one of the most fundamental approaches toward adjusting the transition temperature in NiTi alloy, which affects the fatigue resistance of NiTi endodontic files. The newly developed NiTi instruments made from controlled memory wire, M-Wire (Dentsply Tulsa Dental Specialties, Tulsa, OK), or R-phase wire represent the next generation of NiTi alloys with improved flexibility and fatigue resistance. The advantages of NiTi files for canal cleaning and shaping are decreased canal transportation and ledging, a reduced risk of file fracture, and faster and more efficient instrumentation. The clinician must understand the nature of different NiTi raw materials and their impact on instrument performance because many new instruments are introduced on a regular basis. This review summarizes the metallurgical properties of next-generation NiTi instruments, the impact of thermomechanical treatment on instrument flexibility, and the resistance to cyclic fatigue and torsion. The aim of this review was to provide clinicians with the knowledge necessary for evidence-based practices, maximizing the benefits from the selection and application of NiTi rotary instruments for root canal treatment. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Formation of nucleoside 5'-polyphosphates from nucleotides and trimetaphosphate

NASA Technical Reports Server (NTRS)

Lohrmann, R.

1975-01-01

Nucleoside 5'-polyphosphates (N5PP) formed when solutions of nucleoside 5'-phosphates (N5P) and trimetaphosphate (TMP) are dessicated at room temperature are studied by paper chromatography, electrophoresis, and metal catalytic reactions. Divalent Mg ion exhibited superior catalytic function to other divalent metal ions in the reaction. Major reaction products are indicated. The importance of the N5PP series, TMP, and N5-triphosphate as substrates of RNA and DNA synthesis, and under postulated prebiotic conditions likely to obtain during prebiological ages of the earth, is emphasized and discussed. Alternate drying and wetting, evaporation from a prebiotic puddle, concentration of solubles in the remaining liquid phase, metal catalysis, and the role of these substances in the formation of amino acids and long-chain polyphosphates are considered.

Critical current density in wire drawn and hydrostatically extruded Nb-Ti superconductors

NASA Technical Reports Server (NTRS)

Alterovitz, S. A.; Woollam, J. A.; Collings, E. W.

1979-01-01

Critical current studies have been made on copper-clad Nb-Ti composite wire prepared under area reductions of 100:1 and 10,000:1 by hydrostatic extrusion (HE), wire drawing and HE plus drawing. Comparative evaluation of the thermomechanical processing equivalent of HE was performed.

Effect of thermo-mechanical process on structure and high temperature shape memory properties of Ti-15Ta-15Zr alloy

NASA Astrophysics Data System (ADS)

Zheng, Xiao-Hang; Sui, Jie-He; Yang, Zhe-Yi; Zhi, Guo-Zhang; Cai, Wei

2017-05-01

Not Available Project support by the National Natural Science Foundation of China (Grant No. 51501049), China Postdoctoral Science Foundation (Grant No. 2015M571405), and the Fundamental Research Funds for the Central Universities, China (Grant No. HIT.NSRIF.20163).

Thermomechanical modelling of laser surface glazing for H13 tool steel

NASA Astrophysics Data System (ADS)

Kabir, I. R.; Yin, D.; Tamanna, N.; Naher, S.

2018-03-01

A two-dimensional thermomechanical finite element (FE) model of laser surface glazing (LSG) has been developed for H13 tool steel. The direct coupling technique of ANSYS 17.2 (APDL) has been utilised to solve the transient thermomechanical process. A H13 tool steel cylindrical cross-section has been modelled for laser power 200 W and 300 W at constant 0.2 mm beam width and 0.15 ms residence time. The model can predict temperature distribution, stress-strain increments in elastic and plastic region with time and space. The crack formation tendency also can be assumed by analysing the von Mises stress in the heat-concentrated zone. Isotropic and kinematic hardening models have been applied separately to predict the after-yield phenomena. At 200 W laser power, the peak surface temperature achieved is 1520 K which is below the melting point (1727 K) of H13 tool steel. For laser power 300 W, the peak surface temperature is 2523 K. Tensile residual stresses on surface have been found after cooling, which are in agreement with literature. Isotropic model shows higher residual stress that increases with laser power. Conversely, kinematic model gives lower residual stress which decreases with laser power. Therefore, both plasticity models could work in LSG for H13 tool steel.

The effect of moisture on the dynamic thermomechanical properties of a graphite/epoxy composite

NASA Technical Reports Server (NTRS)

Sykes, G. F.; Burks, H. D.; Nelson, J. B.

1977-01-01

A study has been made of the effect of moisture absorption on the dynamic thermomechanical properties of a graphite/epoxy composite recently considered for building primary aircraft structures. Torsional braid analysis (TBA) and thermomechanical analysis (TMA) techniques were used to measure changes in the glass transition temperature (Tg) and the initial softening temperature (heat distortion temperature, HDT) of T-300/5209 graphite/epoxy composites exposed to room temperature water soak.

Study of Crystallographic Texture During Thermo-Mechanical Processing of Boron Modified Ti-Alloys

DTIC Science & Technology

2009-07-15

project developed a processing strategy for boron-modified titanium alloy Ti- 6Al - 4V , and developed an understanding of the deformation and...develop the processing strategy for boron modified titanium alloy Ti- 6Al - 4V 2. To understand the deformation and transformation mechanisms as a function...strength-to-weight ratio, excellent mechanical properties and corrosion resistance, titanium (Ti) and its alloys, especially (α+β) alloys like Ti- 6Al - 4V

Strengthening of Aluminum Alloy 2219 by Thermo-mechanical Treatment

NASA Astrophysics Data System (ADS)

Li, Xifeng; Lei, Kun; Song, Peng; Liu, Xinqin; Zhang, Fei; Li, Jianfei; Chen, Jun

2015-10-01

Strengthening of aluminum alloy 2219 by thermo-mechanical treatment has been compared with artificial aging. Three simple deformation modes including pre-stretching, compression, and rolling have been used in thermo-mechanical treatment. The tensile strength, elongation, fracture feature, and precipitated phase have been investigated. The results show that the strengthening effect of thermo-mechanical treatment is better than the one of artificial aging. Especially, the yield strength significantly increases with a small decrease of elongation. When the specimen is pre-stretched to 8.0%, the yield strength reaches 385.0 MPa and increases by 22.2% in comparison to the one obtained in aging condition. The maximum tensile strength of 472.4 MPa is achieved with 4.0% thickness reduction by compression. The fracture morphology reveals locally ductile and brittle failure mechanism, while the coarse second-phase particles distribute on the fracture surface. The intermediate phases θ″ or θ' orthogonally precipitate in the matrix after thermo-mechanical treatment. As compared to artificial aging, the cold plastic deformation increases distribution homogeneity and the volume fraction of θ'' or θ' precipitates. These result in a better strengthening effect.

Interactive effects of aging parameters of AA6056

NASA Astrophysics Data System (ADS)

Dehghani, Kamran; Nekahi, Atiye

2012-10-01

The effect of thermomechanical treatment on the aging behavior of AA6056 aluminum alloy was modeled using response surface methodology (RSM). Two models were developed to predict the final yield stress (FYS) and elongation amounts as well as the optimum conditions of aging process. These were done based on the interactive effects of applied thermomechanical parameters. The optimum condition predicted by the model to attain the maximum strength was pre-aging at 80 °C for 15 h, followed by 70% cold work and subsequent final aging at 165 °C for 4 h, which resulted in the FYS of about 480 MPa. As for the elongation, the optimum condition was pre-aging at 80 °C for 15 h, followed by 30% cold work and final-aging at 165 °C for 4 h, which led to 21% elongation. To verify the suggested optimum conditions, the tests were carried out confirming the high accuracy (above 94%) of the RSM technique as well as the developed models. It is shown that the RSM can be used successfully to optimize the aging process, to determine the significance of aging parameters and to model the combination effect of process variables on the aging behavior of AA6056.

Microstructure Evolution and Composition Control During the Processing of Thin-Gage Metallic Foil

NASA Astrophysics Data System (ADS)

Semiatin, S. L.; Gross, M. E.; Matson, D. W.; Bennett, W. D.; Bonham, C. C.; Ustinov, A. I.; Ballard, D. L.

2012-12-01

The manufacture of thin-gage superalloy and gamma-titanium-aluminide foil products via near-conventional thermomechanical processing and two different vapor-deposition methods was investigated. Thermomechanical processing was based on hot-pack rolling of plate and sheet. Foils of the superalloy LSHR and the near-gamma titanium aluminide Ti-45.5Al-2Cr-2Nb made by this approach exhibited excellent gage control and fine two-phase microstructures. The vapor-phase techniques used magnetron sputtering (MS) of a target of the desired product composition or electron-beam physical vapor deposition (EBPVD) of separate targets of the specific alloying elements. Thin deposits of LSHR and Ti-48Al-2Cr-2Nb made by MS showed uniform thickness/composition and an ultrafine microstructure. However, systematic deviations from the specific target composition were found. During subsequent heat treatment, the microstructure of the MS samples showed various degrees of grain growth and coarsening. Foils of Ti-43Al and Ti-51Al-1V fabricated by EBPVD were fully dense. The microstructures developed during EBPVD were interpreted in terms of measured phase equilibria and the dependence of evaporant flux on temperature.

Effective thermo-mechanical properties and shape memory effect of CNT/SMP composites

NASA Astrophysics Data System (ADS)

Yang, Qingsheng; Liu, Xia; Leng, Fangfang

2009-07-01

Shape memory polymer (SMP) has been applied in many fields as intelligent sensors and actuators. In order to improve the mechanical properties and recovery force of SMP, the addition of minor amounts of carbon nanotubes (CNT) into SMP has attracted wide attention. A micromechanical model and thermo-mechanical properties of CNT/SMP composites were studied in this paper. The thermo-mechanical constitutive relation of intellectual composites with isotropic and transversely isotropic CNT was obtained. Moreover, the shape memory effect of CNT/SMP composites and the effect of temperature and the volume fraction of CNT were discussed. The work shows that CNT/SMP composites exhibit excellent macroscopic thermo-mechanical properties and shape memory effect, while both of them can be affected remarkably by temperature and the microstructure parameters.

An anisotropic thermomechanical damage model for concrete at transient elevated temperatures.

PubMed

Baker, Graham; de Borst, René

2005-11-15

The behaviour of concrete at elevated temperatures is important for an assessment of integrity (strength and durability) of structures exposed to a high-temperature environment, in applications such as fire exposure, smelting plants and nuclear installations. In modelling terms, a coupled thermomechanical analysis represents a generalization of the computational mechanics of fracture and damage. Here, we develop a fully coupled anisotropic thermomechanical damage model for concrete under high stress and transient temperature, with emphasis on the adherence of the model to the laws of thermodynamics. Specific analytical results are given, deduced from thermodynamics, of a novel interpretation on specific heat, evolution of entropy and the identification of the complete anisotropic, thermomechanical damage surface. The model is also shown to be stable in a computational sense, and to satisfy the laws of thermodynamics.

Effects of Microstructural Variability on Thermo-Mechanical Properties of a Woven Ceramic Matrix Composite

NASA Technical Reports Server (NTRS)

Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

2013-01-01

The objectives of this paper include identifying important architectural parameters that describe the SiC/SiC five-harness satin weave composite and characterizing the statistical distributions and correlations of those parameters from photomicrographs of various cross sections. In addition, realistic artificial cross sections of a 2D representative volume element (RVE) are generated reflecting the variability found in the photomicrographs, which are used to determine the effects of architectural variability on the thermo-mechanical properties. Lastly, preliminary information is obtained on the sensitivity of thermo-mechanical properties to architectural variations. Finite element analysis is used in combination with a response surface and it is shown that the present method is effective in determining the effects of architectural variability on thermo-mechanical properties.

Dynamic-mechanical and thermomechanical properties of cellulose nanofiber/polyester resin composites.

PubMed

Lavoratti, Alessandra; Scienza, Lisete Cristine; Zattera, Ademir José

2016-01-20

Composites of unsaturated polyester resin (UPR) and cellulose nanofibers (CNFs) obtained from dry cellulose waste of softwood (Pinus sp.) and hardwood (Eucalyptus sp.) were developed. The fiber properties and the influence of the CNFs in the dynamic-mechanical and thermomechanical properties of the composites were evaluated. CNFs with a diameter of 70-90 nm were obtained. Eucalyptus sp. has higher α-cellulose content than Pinus sp. fibers. The crystallinity of the cellulose pulps decreased after grinding. However, high values were still obtained. The chemical composition of the fibers was not significantly altered by the grinding process. Eucalyptus sp. CNF composites had water absorption close to the neat resin at 1 wt% filler. The dynamic-mechanical properties of Eucalyptus sp. CNFs were slightly increased and the thermal stability was improved. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nonidentity of Some Simian Virus 40-induced Enzymes with Tumor Antigen

PubMed Central

Kit, Saul; Melnick, Joseph L.; Anken, Milton; Dubbs, Del Rose; de Torres, R. A.; Kitahara, Tsunehiro

1967-01-01

The complement-fixing tumor (T) antigen induced by simian virus 40 (SV40) has been prepared from SV40-infected cell cultures, from infected cell cultures treated at the time of infection with 1-β-d-arabinofuranosylcytosine (ara-C), and from SV40-transformed cells. Upon partial purification, the T antigen exhibited the following properties: it was tightly adsorbed by calcium phosphate gel, it was precipitated by acetic acid at pH 5 or by ammonium sulfate at about 20 to 32% saturation, and it had a molecular weight greater than 250,000, as estimated by Sephadex G-200 gel chromatography. In contrast, deoxycytidylate (dCMP) deaminase, thymidylate (dTMP) kinase, and thymidine (dT) kinase were less strongly bound to calcium phosphate and were not precipitated at pH 5; these enzymes also had much lower molecular weights than the T antigen, as did dihydrofolic (FH2) reductase. Furthermore, higher ammonium sulfate concentrations were required to precipitate dCMP deaminase, dTMP kinase, and FH2 reductase activities than to precipitate the T antigen. Another difference was that the T antigen was not stabilized, but dCMP deaminase, dTMP kinase, and dT kinase, were stabilized, respectively, by dCTP, dTMP, and dT or dTTP. Deoxyribonucleic acid (DNA) polymerase activity resembled the T antigen in adsorption to calcium phosphate, in precipitation by ammonium sulfate or at pH 5, and in the rate of inactivation when incubated at 38 C. However, the polymerase activity could be partly separated from the T antigen by Sephadex G-200 gel chromatography. The cell fraction containing partially purified T antigen also contained a soluble complement-fixing antigen (presumably a subunit of the viral capsid) which reacted with hyperimmune monkey sera. The latter antigen was present in very low titers or absent from cell extracts prepared from SV40-infected monkey kidney cell cultures which had been treated with ara-C at the time of infection, or from SV40-transformed mouse kidney (mKS) or hamster tumor (H-50) cells. The T antigen, however, was present in usual amounts in SV40-transformed cells or ara-C treated, infected cells. PMID:4316227

Did the reporting of prognostic studies of tumour markers improve since the introduction of REMARK guideline? A comparison of reporting in published articles

PubMed Central

Mallett, Susan; Altman, Douglas G.; Sauerbrei, Willi

2017-01-01

Although biomarkers are perceived as highly relevant for future clinical practice, few biomarkers reach clinical utility for several reasons. Among them, poor reporting of studies is one of the major problems. To aid improvement, reporting guidelines like REMARK for tumour marker prognostic (TMP) studies were introduced several years ago. The aims of this project were to assess whether reporting quality of TMP-studies improved in comparison to a previously conducted study assessing reporting quality of TMP-studies (PRE-study) and to assess whether articles citing REMARK (citing group) are better reported, in comparison to articles not citing REMARK (not-citing group). For the POST-study, recent articles citing and not citing REMARK (53 each) were identified in selected journals through systematic literature search and evaluated in same way as in the PRE-study. Ten of the 20 items of the REMARK checklist were evaluated and used to define an overall score of reporting quality. The observed overall scores were 53.4% (range: 10%-90%) for the PRE-study, 57.7% (range: 20%-100%) for the not-citing group and 58.1% (range: 30%-100%) for the citing group of the POST-study. While there is no difference between the two groups of the POST-study, the POST-study shows a slight but not relevant improvement in reporting relative to the PRE-study. Not all the articles of the citing group, cited REMARK appropriately. Irrespective of whether REMARK was cited, the overall score was slightly higher for articles published in journals requesting adherence to REMARK than for those published in journals not requesting it: 59.9% versus 51.9%, respectively. Several years after the introduction of REMARK, many key items of TMP-studies are still very poorly reported. A combined effort is needed from authors, editors, reviewers and methodologists to improve the current situation. Good reporting is not just nice to have but is essential for any research to be useful. PMID:28614415

Validated electrochemical and chromatographic quantifications of some antibiotic residues in pharmaceutical industrial waste water.

PubMed

Ibrahim, Heba K; Abdel-Moety, Mona M; Abdel-Gawad, Sherif A; Al-Ghobashy, Medhat A; Kawy, Mohamed Abdel

2017-03-01

Realistic implementation of ion selective electrodes (ISEs) into environmental monitoring programs has always been a challenging task. This could be largely attributed to difficulties in validation of ISE assay results. In this study, the electrochemical response of amoxicillin trihydrate (AMX), ciprofloxacin hydrochloride (CPLX), trimethoprim (TMP), and norfloxacin (NFLX) was studied by the fabrication of sensitive membrane electrodes belonging to two types of ISEs, which are polyvinyl chloride (PVC) membrane electrodes and glassy carbon (GC) electrodes. Linear response for the membrane electrodes was in the concentration range of 10 -5 -10 -2  mol/L. For the PVC membrane electrodes, Nernstian slopes of 55.1, 56.5, 56.5, and 54.0 mV/decade were achieved over a pH 4-8 for AMX, CPLX, and NFLX, respectively, and pH 3-6 for TMP. On the other hand, for GC electrodes, Nernstian slopes of 59.1, 58.2, 57.0, and 58.2 mV/decade were achieved over pH 4-8 for AMX, CPLX, and NFLX, respectively, and pH 3-6 for TMP. In addition to assay validation to international industry standards, the fabricated electrodes were also cross-validated relative to conventional separation techniques; high performance liquid chromatography (HPLC), and thin layer chromatography (TLC)-densitometry. The HPLC assay was applied in concentration range of 0.5-10.0 μg/mL, for all target analytes. The TLC-densitometry was adopted over a concentration range of 0.3-1.0 μg/band, for AMX, and 0.1-0.9 μg/band, for CPLX, NFLX, and TMP. The proposed techniques were successfully applied for quantification of the selected drugs either in pure form or waste water samples obtained from pharmaceutical plants. The actual waste water samples were subjected to solid phase extraction (SPE) for pretreatment prior to the application of chromatographic techniques (HPLC and TLC-densitometry). On the other hand, the fabricated electrodes were successfully applied for quantification of the antibiotic residues in actual waste water samples without any pretreatment. This finding assures the suitability of the fabricated ISEs for environmental analysis.

Side-chain conformation of the M2 transmembrane peptide proton channel of influenza a virus from 19F solid-state NMR.

PubMed

Luo, Wenbin; Mani, Rajeswari; Hong, Mei

2007-09-13

The M2 transmembrane peptide (M2TMP) of the influenza A virus forms a tetrameric helical bundle that acts as a proton-selective channel important in the viral life cycle. The side-chain conformation of the peptide is largely unknown and is important for elucidating the proton-conducting mechanism and the channel stability. Using a 19F spin diffusion NMR technique called CODEX, we have measured the oligomeric states and interhelical side chain-side chain 19F-19F distances at several residues using singly fluorinated M2TMP bound to DMPC bilayers. 19F CODEX data at a key residue of the proton channel, Trp41, confirm the tetrameric state of the peptide and yield a nearest-neighbor interhelical distance of approximately 11 A under both neutral and acidic pH. Since the helix orientation is precisely known from previous 15N NMR experiments and the backbone channel diameter has a narrow allowed range, this 19F distance constrains the Trp41 side-chain conformation to t90 (chi1 approximately 180 degrees , chi2 approximately 90 degrees ). This Trp41 rotamer, combined with a previously measured 15N-13C distance between His37 and Trp411, suggests that the His37 rotamer is t-160. The implication of the proposed (His37, Trp41) rotamers to the gating mechanism of the M2 proton channel is discussed. Binding of the antiviral drug amantadine to the peptide does not affect the F-F distance at Trp41. Interhelical 19F-19F distances are also measured at residues 27 and 38, each mutated to 4-19F-Phe. For V27F-M2TMP, the 19F-19F distances suggest a mixture of dimers and tetramers, whereas the L38F-M2TMP data indicate two tetramers of different sizes, suggesting side chain conformational heterogeneity at this lipid-facing residue. This work shows that 19F spin diffusion NMR is a valuable tool for determining long-range intermolecular distances that shed light on the mechanism of action and conformational heterogeneity of membrane protein oligomers.

Laser and Surface Processes of NiTi Shape Memory Elements for Micro-actuation

NASA Astrophysics Data System (ADS)

Nespoli, Adelaide; Biffi, Carlo Alberto; Previtali, Barbara; Villa, Elena; Tuissi, Ausonio

2014-04-01

In the current microtechnology for actuation field, shape memory alloys (SMA) are considered one of the best candidates for the production of mini/micro devices thanks to their high power-to-weight ratio as function of the actuator weight and hence for their capability of generating high mechanical performance in very limited spaces. In the microscale the most suitable conformation of a SMA actuator is given by a planar wavy formed arrangement, i.e., the snake-like shape, which allows high strokes, considerable forces, and devices with very low sizes. This uncommon and complex geometry becomes more difficult to be realized when the actuator dimensions are scaled down to micrometric values. In this work, micro-snake-like actuators are laser machined using a nanosecond pulsed fiber laser, starting from a 120- μm-thick NiTi sheet. Chemical and electrochemical surface polishes are also investigated for the removal of the thermal damages of the laser process. Calorimetric and thermo-mechanical tests are accomplished to assess the NiTi microdevice performance after each step of the working process. It is shown that laser machining has to be followed by some post-processes in order to obtain a micro-actuator with good thermo-mechanical properties.

Mechanical rejuvenation in bulk metallic glass induced by thermo-mechanical creep

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

Tong, Yang; Dmowski, W.; Bei, Hongbin

Using high energy X-ray diffraction we studied the temperature, stress, and time effect on structural changes in a Zr-based bulk metallic glass induced by thermo-mechanical creep. Pair distribution functions obtained from two-dimensional diffraction patterns show that thermo-mechanical creep induces structural disordering, but only when the stress beyond a threshold is applied. A similar threshold behavior was observed for anelastic strain. We conclude that anelastic creep strain induces rejuvenation, whereas plastic strain does not.

Mechanical rejuvenation in bulk metallic glass induced by thermo-mechanical creep

DOE PAGES

Tong, Yang; Dmowski, W.; Bei, Hongbin; ...

2018-02-16

Using high energy X-ray diffraction we studied the temperature, stress, and time effect on structural changes in a Zr-based bulk metallic glass induced by thermo-mechanical creep. Pair distribution functions obtained from two-dimensional diffraction patterns show that thermo-mechanical creep induces structural disordering, but only when the stress beyond a threshold is applied. A similar threshold behavior was observed for anelastic strain. We conclude that anelastic creep strain induces rejuvenation, whereas plastic strain does not.

40 CFR 430.74 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

40 CFR 430.72 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... through the application of the thermo-mechanical process] Pollutant or pollutant property Kg/kkg (or... where pulp and paper at groundwood chemi-mechanical mills are produced] Pollutant or pollutant property... Mechanical Pulp Subcategory § 430.72 Effluent limitations representing the degree of effluent reduction...

40 CFR 430.74 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

Processing and Characterization of Cellulose Nanocrystals/Polylactic Acid Nanocomposite Films

Treesearch

Erin Sullivan; Robert Moon; Kyriaki Kalaitzidou

2015-01-01

The focus of this study is to examine the effect of cellulose nanocrystals (CNC) on the properties of polylactic acid (PLA) films. The films are fabricated via melt compounding and melt fiber spinning followed by compression molding. Film fracture morphology, thermal properties, crystallization behavior, thermo-mechanical behavior, and mechanical behavior were...

Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

2000-01-01

Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

Influence of thermo-mechanical treatment in ferritic phase field on microstructure and mechanical properties of reduced activation ferritic-martensitic steel

NASA Astrophysics Data System (ADS)

Prakash; Vanaja, J.; Laha, K.; Nageswara Rao, G. V. S.

2018-03-01

The present study focuses on the evaluation of microstructure and mechanical properties of reduced activation ferritic-martensitic (RAFM) steel (9Cr-1W-0.06Ta) subjected to thermo-mechanical treatment (TMT) in ferritic phase field. The results obtained were compared with the steel in conventional normalised plus tempered (N+T) condition. The microstructure of the steel in N+T and TMT conditions was assessed by optical and scanning electron microscopes. Hardness, tensile and creep studies were carried out and the results were correlated with the microstructural studies. While the TMT processed steel resulted in coarser prior austenite grains and exhibited ferritic microstructure with large distribution of fine M23C6 and MX precipitates, the N+T steel reveals tempered martensitic structure with finer prior austenitic grains with coarser M23C6 and MX precipitates. Although ferritic structure is present in TMT processed steel, it exhibits better tensile and creep rupture strengths than N+T steel due to the presence of increased dislocation density and finer distribution of precipitates.

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

Yasuda, H.; Chong, C.; Charalampidis, E. G.

Here, we investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron (TMP) unit cells. These cells exhibit strain softening behavior under compression, which can be tuned by modifying their geometrical configurations or initial folded conditions. We assemble these TMP cells into a cluster of origami-based metamaterials, and we theoretically model and numerically analyze their wave transmission mechanism under external impact. Numerical simulations show that origami-based metamaterials can provide a prototypical platform for the formation of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront upon the application of compression to the system.more » We also demonstrate the existence of numerically exact traveling rarefaction waves in an effective lumped-mass model. Origami-based metamaterials can be highly useful for mitigating shock waves, potentially enabling a wide variety of engineering applications.« less

Formation of rarefaction waves in origami-based metamaterials

NASA Astrophysics Data System (ADS)

Yasuda, H.; Chong, C.; Charalampidis, E. G.; Kevrekidis, P. G.; Yang, J.

2016-04-01

We investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron (TMP) unit cells. These cells exhibit strain softening behavior under compression, which can be tuned by modifying their geometrical configurations or initial folded conditions. We assemble these TMP cells into a cluster of origami-based metamaterials, and we theoretically model and numerically analyze their wave transmission mechanism under external impact. Numerical simulations show that origami-based metamaterials can provide a prototypical platform for the formation of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront upon the application of compression to the system. We also demonstrate the existence of numerically exact traveling rarefaction waves in an effective lumped-mass model. Origami-based metamaterials can be highly useful for mitigating shock waves, potentially enabling a wide variety of engineering applications.

Design, synthesis, antibacterial activity and docking study of some new trimethoprim derivatives.

PubMed

Rashid, Umer; Ahmad, Waqas; Hassan, Syed Fahad; Qureshi, Naveeda Akhtar; Niaz, Basit; Muhammad, Bakhtiar; Imdad, Sameera; Sajid, Muhammad

2016-12-01

In present study, nineteen novel trimethoprim (TMP) derivatives were designed, synthesized and evaluated for their antibacterial potential. Hydroxy trimethoprim 2 (HTMP) was synthesized by following the demethylation of 4-methoxy group at trimethoxy benzyl ring of TMP. Structure-activity relationship (SAR) studies were explored on HTMP by incorporating various substituents leading to the identification of some new compounds with improved antibacterial activities. The results revealed that the introduction of benzyloxy (4a-e) and phenyl ethanone (5a-e) group at 4-position of dimethoxy benzyl ring leads to overall increase in the antibacterial activity. The most potent antibacterial compound discovered is benzyloxy derivative 4b with MIC value of 5.0μM against Staphylococcus aureus and 4.0μM against Escherichia coli strains higher than the standard TMP (22.7μM against S. aureus and 55.1μM against E. coli). Substitution at 4-NH 2 group was not tolerated and the resulting Schiff base derivatives 3a-h demonstrated very little or no antibacterial activity in the tested concentration domain. We further performed exploratory docking studies on dihydrofolate reductase (DHFR) to rationalize the in vitro biological data and to demonstrate the mechanism of antibacterial activity. For the ability to cross lipophilic outer membrane, logP was computed. It was found that the compounds possessing high hydrophobicity have high activity against E. coli. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation into the susceptibility of Burkholderia cepacia complex isolates to photodynamic antimicrobial chemotherapy (PACT)

NASA Astrophysics Data System (ADS)

Cassidy, C. M.; Watters, A. L.; Donnelly, R. F.; Tunney, M. M.

2009-06-01

The main cause of morbidity and mortality in cystic fibrosis (CF) sufferers is progressive pulmonary damage caused by recurrent and often unremitting respiratory tract infection. Causative organisms include Pseudomonas aeruginosa and Haemophilus influenzae, but in recent years the Burkholderia cepacia complex has come to the fore. This group of highly drug-resistant Gram-negative bacteria are associated with a rapid decline in lung function and the often fatal cepacia syndrome, with treatment limited to patient segregation and marginally effective antibacterial regimens. Thus, development of an effective treatment is of the upmost importance. PACT, a non-target specific therapy, has proven successful in killing both Gram-positive and Gram-negative bacteria. In this study, planktonic cultures of six strains of the B. cepacia complex were irradiated (635 nm, 200 J cm-2,10 minutes irradiation) following 30 seconds incubation with methylene blue (MB) or meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP). Rates of kill of > 99 % were achieved with MB- and TMP-PACT. A MB concentration of 50 μg ml-1 and TMP concentration of 500 μg ml-1 were associated with highest percentage kills for each photosensitizer. PACT is an attractive option for treatment of B.cepacia complex infection. Further study, involving biofilm culture susceptibility, delivery of light to the target and in vivo testing will be necessary before it PACT becomes a viable treatment option for CF patients who are colonised or infected with B. cepacia complex.

Strategies to prepare and use functionalized organometallic reagents.

PubMed

Klatt, Thomas; Markiewicz, John T; Sämann, Christoph; Knochel, Paul

2014-05-16

Polyfunctional zinc and magnesium organometallic reagents occupy a central position in organic synthesis. Most organic functional groups are tolerated by zinc organometallic reagents, and Csp(2)-centered magnesium organometallic reagents are compatible with important functional groups, such as the ester, aryl ketone, nitro, cyano, and amide functions. This excellent chemoselectivity gives zinc- and magnesium-organometallic reagents a central position in modern organic synthesis. Efficient and general preparations of these organometallic reagents, as well as their most practical and useful reactions, are presented in this Perspective. As starting materials, a broad range of organic halides (iodides, bromides, and also to some extent chlorides) can be used for the direct insertion of magnesium or zinc powder; the presence of LiCl very efficiently promotes such insertions. Alternatively, aromatic or heterocyclic bromides also undergo a smooth bromine-magnesium exchange when treated with i-PrMgCl·LiCl. Alternative precursors of zinc and magnesium reagents are polyfunctionalized aryl and heteroaryl molecules, which undergo directed metalations with sterically hindered TMP bases (TMP = 2,2,6,6-tetramethylpiperide) of magnesium and zinc. This powerful C-H functionalization method gives access to polyfunctional heterocyclic zinc and magnesium reagents, which undergo efficient reactions with numerous electrophiles. The compatibility of the strong TMP-bases with BF3·OEt2 (formation of frustrated Lewis pairs) dramatically increases the scope of these metalations, giving for example, a practical access to magnesiated pyridines and pyrazines, which can be used as convenient building blocks for the preparation of biologically active molecules.

Modelling the influence of thermal effects induced by radio frequency electric field on the dynamics of the ATPase nano-biomolecular motors.

PubMed

Lohrasebi, A; Mohamadi, S; Fadaie, S; Rafii-Tabar, H

2012-07-01

We model the dynamics of the F(0) component of the F(0)F(1)-ATPase mitochondrion-based nano-motor operating in a stochastically-fluctuating medium that represents the intracellular environment. The stochastic dynamics are modeled via Langevin equation of motion wherein fluctuations are treated as white noise. We have investigated the influence of an applied alternating electric field on the rotary motion of the F(0) rotor in such an environment. The exposure to the field induces a temperature rise in the mitochondrion's membrane, within which the F(0) is embedded. The external field also induces an electric potential that promotes a change in the mitochondrion's transmembrane potential (TMP). Both the induced temperature and the change in TMP contribute to a change in the dynamics of the F(0). We have found that for external fields in the radio frequency (RF) range, normally present in the environment and encountered by biological systems, the contribution of the induced thermal effects, relative to that of the induced TMP, to the dynamics of the F(0) is more significant. The changes in the dynamics of the F(0) part affect the frequency of the rotary motion of the F(0)F(1)-ATPase protein motor which, in turn, affects the production rate of the ATP molecules. Copyright © 2011 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The expanding role of fluoroquinolones.

PubMed

Schaeffer, Anthony J

2003-02-01

There has been a growing rate of resistance among common urinary tract pathogens, such as Escherichia coli, to traditional antimicrobial therapies including the "gold standard" trimethoprim-sulfamethoxazole (TMP-SMX). Consequently, fluoroquinolone antimicrobial agents have taken on an expanding management role for UTIs. In fact, the recent Infectious Diseases Society of America clinical management guidelines for UTI recommend fluoroquinolones as first-line therapy for uncomplicated UTI in areas where resistance is likely to be of concern. Fluoroquinolones have demonstrated high bacteriologic and clinical cure rates, as well as low rates of resistance, among most common uropathogens. There are currently 7 fluoroquinolones with indications for UTI in the United States. However, only 3 are commonly used: levofloxacin, ciprofloxacin, and, to a lesser extent, gatifloxacin. Many of the fluoroquinolone agents have once-daily dosing regimens, enhancing patient adherence. In addition, levofloxacin and gatifloxacin have same-dose bioequivalency between their intravenous and oral formulations, allowing for "switch" or step-down therapy from parenteral to oral formulations of the same agent at the same dose. Fluoroquinolones are indicated for the management of acute uncomplicated UTIs, as well as complicated and severe UTI and pyelonephritis, in adults. They are the first-line treatment of acute uncomplicated cystitis in patients who cannot tolerate sulfonamides or TMP, who live in geographic areas with known resistance >10% to 20% to TMP-SMX, or who have risk factors for such resistance. Fluoroquinolone properties include a broad spectrum of coverage, low rates of resistance, and good safety profiles.

Vitamin D as Supplemental Therapy for Pneumocystis Pneumonia.

PubMed

Lei, Guang-Sheng; Zhang, Chen; Zimmerman, Michelle K; Lee, Chao-Hung

2015-12-14

The combination of all-trans retinoic acid (ATRA) and primaquine (PMQ) has been shown to be effective for therapy of Pneumocystis pneumonia (PCP). Since a high concentration of ATRA has significant adverse effects, the possibility that vitamin D can be used to replace ATRA for PCP therapy was investigated. C57BL/6 mice were immunosuppressed by depleting CD4(+) cells and infected with Pneumocystis murina 1 week after initiation of immunosuppression. Three weeks after infection, the mice were treated orally for 3 weeks with vitamin D3 (VitD3) alone, PMQ alone, a combination of VitD3 and PMQ (VitD3-PMQ), or a combination of trimethoprim and sulfamethoxazole (TMP-SMX). Results showed that VitD3 (300 IU/kg/day) had a synergistic effect with PMQ (5 mg/kg/day) for therapy of PCP. Flow cytometric studies showed that this VitD3-PMQ combination recovered the CD11b(low) CD11c(high) alveolar macrophage population in mice with PCP as effectively as TMP-SMX. The VitD3-PMQ combination also reduced the massive infiltration of inflammatory cells into the lungs and the severity of lung damage. VitD3 was also shown to reduce the dose of TMP-SMX required for effective treatment of PCP. Taken together, results of this study suggest that a VitD3-PMQ combination can be used as an alternative therapy for PCP. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The thermomechanical stability of micro-solid oxide fuel cells fabricated on anodized aluminum oxide membranes

NASA Astrophysics Data System (ADS)

Kwon, Chang-Woo; Lee, Jae-Il; Kim, Ki-Bum; Lee, Hae-Weon; Lee, Jong-Ho; Son, Ji-Won

2012-07-01

The thermomechanical stability of micro-solid oxide fuel cells (micro-SOFCs) fabricated on an anodized aluminum oxide (AAO) membrane template is investigated. The full structure consists of the following layers: AAO membrane (600 nm)/Pt anode/YSZ electrolyte (900 nm)/porous Pt cathode. The utilization of a 600-nm-thick AAO membrane significantly improves the thermomechanical stability due to its well-known honeycomb-shaped nanopore structure. Moreover, the Pt anode layer deposited in between the AAO membrane and the YSZ electrolyte preserves its integrity in terms of maintaining the triple-phase boundary (TPB) and electrical conductivity during high-temperature operation. Both of these results guarantee thermomechanical stability of the micro-SOFC and extend the cell lifetime, which is one of the most critical issues in the fabrication of freestanding membrane-type micro-SOFCs.

NBS: Nondestructive evaluation of nonuniformities in 2219 aluminum alloy plate: Relationship to processing

NASA Technical Reports Server (NTRS)

Swartzendruber, L.; Boettinger, W.; Ives, L.; Coriell, S.; Ballard, D.; Laughlin, D.; Clough, R.; Biancanieilo, F.; Blau, P.; Cahn, J.

1980-01-01

The compositional homogeneity, microstructure, hardness, electrical conductivity and mechanical properties of 2219 aluminum alloy plates are influenced by the process variables during casting, rolling and thermomechanical treatment. The details of these relationships wre investigated for correctly processed 2219 plate as well as for deviations caused by improper quenching after solution heat treatment. Primary emphasis was been placed on the reliability of eddy current electrical conductivity and hardness as NDE tools to detect variations in mechanical properties.

The influence of manufacturing processes on the microstructure, grain boundary characteristics and SCC behavior of Alloy 690 steam generator tubing

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

Sarver, J.M.; Doherty, P.E.; Doyle, D.M.

1995-12-31

Thermally treated Alloy 690 is the tubing material of choice for replacement steam generators in the United States. Throughout the world, it is manufactured using different melting and thermomechanical processing methods. The influence of different processing steps on the intergranular stress corrosion cracking (IGSCC) behavior of Alloy 690 has not been thoroughly evaluated. Evaluations were performed on Alloy 690 steam generator tubing produced using several different melting practices and thermomechanical processing procedures. The evaluations included extensive microstructural examinations as well as constant extension rate (CERT) tests. The CERT test results indicated that the thermally treated Alloy 690 tubing which wasmore » subjected to higher annealing temperatures displayed the highest degree of resistance to stress corrosion cracking (SCC). Examination of the microstructures indicated that the microstructural changes which are produced by increased annealing temperatures are subtle. In an attempt to further elucidate and quantify the effect of manufacturing processes on corrosion behavior, grain boundary character distribution (GBCD) measurements were performed on the same materials which were CERT tested. Analysis of GBCDs of the samples used in this study indicate that Alloy 690 exhibits a significantly larger fraction of special boundaries as compared to Alloy 600 and Alloy 800, regardless of the processing history of the tubing. Preliminary results indicate that a correlation may exist between processing method, GBCD`s and degree of IGSCC exhibited by the thermally treated samples examined in this study.« less

Bioaccumulation and tissue distribution of antibiotics in wild marine fish from Laizhou Bay, North China.

PubMed

Liu, Sisi; Bekele, Tadiyose-Girma; Zhao, Hongxia; Cai, Xiyun; Chen, Jingwen

2018-08-01

Information about bioaccumulation and tissue distribution of antibiotics in wild marine fish is still limited. In the present study, tissue levels, bioaccumulation and distribution patterns of 9 sulfonamide (SA), trimethoprim (TMP), 5 fluoroquinolone (FQ), and 4 macrolide (ML) antibiotics were investigated in gill, muscle, kidney, and liver tissues of seven wild fish species collected from Laizhou Bay, North China in 2016. All the 19 antibiotics were detected in these fish tissues with the total concentrations ranging from 22ng/g dry weight (dw) to 500ng/g dw. The mean values of logarithm bioaccumulation factors (BAFs) in the gills, muscles, kidneys, and livers ranged from 2.2 to 4.8, 1.9 to 4.0, 2.5 to 4.9, and 2.5 to 5.4, respectively. Log BAFs of antibiotics in these tissues significantly increased (r=0.61-0.77, p<0.001) with their logarithm values of liposome-water distribution coefficient (D lipw ) except in the muscles, suggesting that D lipw can well assess the bioaccumulation potentials of antibiotics in phospholipid-rich tissues. In general, the SAs, TMP, and FQs were primarily accumulated in the muscles and the MLs were primarily in the livers, which may be related to their toxicokinetic processes of these marine fish. The present study for the first time reported the tissue distribution patterns of antibiotics in wild marine fish. Copyright © 2018 Elsevier B.V. All rights reserved.

Process Modeling Applied to Metal Forming and Thermomechanical Processing

DTIC Science & Technology

1984-09-01

the flow stress of structural alloys de- creases with temperature. It is well accepted that the homologous temperature, the ratio of the absolute...hardening coefficient y reducing to the value y = 1. This is simply the well - known Considere condition. The influence of strain rate sensitivity on...obtained by sent, well understood [6]. It is also important to note that no way rate effects explicitly in the Hill theory. Thus, comparisons of the

Strengthening and toughening mechanisms in low-c microalloyed martensitic steel as influenced by austenite conditioning

NASA Astrophysics Data System (ADS)

Kennett, Shane C.

Three low-carbon ASTM A514 microalloyed steels were used to assess the effects of austenite conditioning on the microstructure and mechanical properties of martensite. A range of prior austenite grain sizes with and without thermomechanical processing were produced in a Gleeble RTM 3500 and direct-quenched. Samples in the as-quenched, low temperature tempered, and high temperature tempered conditions were studied. The microstructure was characterized with scanning electron microscopy, electron backscattered diffraction, transmission electron microscopy, and x-ray diffraction. The uniaxial tensile properties and Charpy V-notch properties were measured and compared with the microstructural features (prior austenite grain size, packet size, block size, lath boundaries, and dislocation density). For the equiaxed prior austenite grain conditions, prior austenite grain size refinement decreases the packet size, decreases the block size, and increases the dislocation density of as-quenched martensite. However, after high temperature tempering the dislocation density decreases with prior austenite grain size refinement. Thermomechanical processing increases the low angle substructure, increases the dislocation density, and decreases the block size of as-quenched martensite. The dislocation density increase and block size refinement is sensitive to the austenite grain size before ausforming. The larger prior austenite grain size conditions have a larger increase in dislocation density, but the small prior austenite grain size conditions have the largest refinement in block size. Additionally, for the large prior austenite grain size conditions, the packet size increases with thermomechanical processing. The strength of martensite is often related to an effective grain size or carbon concentration. For the current work, it was concluded that the strength of martensite is primarily controlled by the dislocation density and dislocation substructure; which is related to a grain size and carbon concentration. In the microyielding regime, the strength and work hardening is related to the motion of unpinned dislocation segments. However, with tensile strain, a dislocation cell structure is developed and the flow strength (greater than 1% offset) is controlled by the dislocation density following a Taylor hardening model, thereby ruling out any grain size effects on the flow strength. Additionally, it is proposed that lath boundaries contribute to strength. It is shown that the strength differences associated with thermomechanically processed steels can be fully accounted for by dislocation density differences and the effect of lath boundaries. The low temperature ductile to brittle transition of martensite is controlled by the martensite block size, packet size, and prior austenite grain size. However, the effect of block size is likely small in comparison. The ductile to brittle transition temperature is best correlated to the inverse square root of the martensite packet size because large crack deflections are typical at packet boundaries.

Guidelines for developing transportation management plans in Virginia.

DOT National Transportation Integrated Search

2005-01-01

A transportation management plan (TMP) is a comprehensive program of traffic control, communication, operation, and demand management strategies designed to maintain acceptable levels of traffic flow in work zones. A systematic procedure and/or check...

Packaging Technology for SiC High Temperature Circuits Operable up to 500 Degrees Centigrade

NASA Technical Reports Server (NTRS)

Chen, Lian-Yu

2002-01-01

New high temperature low power 8-pin packages have been fabricated using commercial fabrication service. These packages are made of aluminum nitride and 96 percent alumina with Au metallization. The new design of these packages provides the chips inside with EM shielding. Wirebond geometry control has been achieved for precise mechanical tests. Au wirebond samples with 45 degree heel-angle have been tested using wireloop test module. The geometry control improves the consistency of measurement of the wireloop breaking point.Also reported on is a parametric study of the thermomechanical reliability of a Au thick-film based SiC die-attach assembly using nonlinear finite element analysis (FEA) was conducted to optimize the die-attach thermo-mechanical performance for operation at temperatures from room temperature to 500 degrees Centigrade. This parametric study centered on material selection, structure design and process control.

Comparison of the thermomechanical characteristics of porcher carbon fabric-based composites for orthopaedic applications

NASA Astrophysics Data System (ADS)

Molchanov, E. S.; Yudin, V. E.; Kydralieva, K. A.; Elokhovskii, V. Yu.

2012-07-01

Prepregs of fiber-reinforced plastics based on a PORCHER-43200 carbon twill-weave fabric and two types of binders — thermoreactive and thermoplastic — were fabricated using electrostatic spraying, followed by rolling the prepregs in temperature-controlled calenders. A solid epoxy olygomer with dicyandiamine as a hardener and Fortron® polyphenylene sulfide were used as the thermoreactive and thermoplastic binders. The thermomechanical properties of carbon-fiber-reinforced plastics processed from these prepregs, as well as commercial Sigranex® PREPREGCE8201-200-45 S prepregs as model ones, and composites manufactured from them were investigated for comparison. The latter ones are being used for the design of orthopaedic products. It is shown that the composites based on polyphenylene sulfide are characterized by higher values of flexural strength, flexural and shear moduli, and interlaminar fracture toughness ( G IC), the latter being the most important parameter.

Active materials by four-dimension printing

NASA Astrophysics Data System (ADS)

Ge, Qi; Qi, H. Jerry; Dunn, Martin L.

2013-09-01

We advance a paradigm of printed active composite materials realized by directly printing glassy shape memory polymer fibers in an elastomeric matrix. We imbue the active composites with intelligence via a programmed lamina and laminate architecture and a subsequent thermomechanical training process. The initial configuration is created by three-dimension (3D) printing, and then the programmed action of the shape memory fibers creates time dependence of the configuration—the four-dimension (4D) aspect. We design and print laminates in thin plate form that can be thermomechanically programmed to assume complex three-dimensional configurations including bent, coiled, and twisted strips, folded shapes, and complex contoured shapes with nonuniform, spatially varying curvature. The original flat plate shape can be recovered by heating the material again. We also show how the printed active composites can be directly integrated with other printed functionalities to create devices; here we demonstrate this by creating a structure that can assemble itself.

Interactive evolution concept for analyzing a rock salt cavern under cyclic thermo-mechanical loading

NASA Astrophysics Data System (ADS)

König, Diethard; Mahmoudi, Elham; Khaledi, Kavan; von Blumenthal, Achim; Schanz, Tom

2016-04-01

The excess electricity produced by renewable energy sources available during off-peak periods of consumption can be used e.g. to produce and compress hydrogen or to compress air. Afterwards the pressurized gas is stored in the rock salt cavities. During this process, thermo-mechanical cyclic loading is applied to the rock salt surrounding the cavern. Compared to the operation of conventional storage caverns in rock salt the frequencies of filling and discharging cycles and therefore the thermo-mechanical loading cycles are much higher, e.g. daily or weekly compared to seasonally or yearly. The stress strain behavior of rock salt as well as the deformation behavior and the stability of caverns in rock salt under such loading conditions are unknown. To overcome this, existing experimental studies have to be supplemented by exploring the behavior of rock salt under combined thermo-mechanical cyclic loading. Existing constitutive relations have to be extended to cover degradation of rock salt under thermo-mechanical cyclic loading. At least the complex system of a cavern in rock salt under these loading conditions has to be analyzed by numerical modeling taking into account the uncertainties due to limited access in large depth to investigate material composition and properties. An interactive evolution concept is presented to link the different components of such a study - experimental modeling, constitutive modeling and numerical modeling. A triaxial experimental setup is designed to characterize the cyclic thermo-mechanical behavior of rock salt. The imposed boundary conditions in the experimental setup are assumed to be similar to the stress state obtained from a full-scale numerical simulation. The computational model relies primarily on the governing constitutive model for predicting the behavior of rock salt cavity. Hence, a sophisticated elasto-viscoplastic creep constitutive model is developed to take into account the dilatancy and damage progress, as well as the temperature effects. The contributed input parameters in the constitutive model are calibrated using the experimental measurements. In the following, the initial numerical simulation is modified based on the introduced constitutive model implemented in a finite element code. However, because of the significant levels of uncertainties involved in the design procedure of such structures, a reliable design can be achieved by employing probabilistic approaches. Therefore, the numerical calculation is extended by statistical tools such as sensitivity analysis, probabilistic analysis and robust reliability-based design. Uncertainties e.g. due to limited site investigation, which is always fragmentary within these depths, can be compensated by using data sets of field measurements for back calculation of input parameters with the developed numerical model. Monitoring concepts can be optimized by identifying sensor localizations e.g. using sensitivity analyses.

Multiaxial and thermomechanical fatigue considerations in damage tolerant design

NASA Technical Reports Server (NTRS)

Leese, G. E.; Bill, R. C.

1985-01-01

In considering damage tolerant design concepts for gas turbine hot section components, several challenging concerns arise: Complex multiaxial loading situations are encountered; Thermomechanical fatigue loading involving very wide temperature ranges is imposed on components; Some hot section materials are extremely anisotropic; and coatings and environmental interactions play an important role in crack propagation. The effects of multiaxiality and thermomechanical fatigue are considered from the standpoint of their impact on damage tolerant design concepts. Recently obtained research results as well as results from the open literature are examined and their implications for damage tolerant design are discussed. Three important needs required to advance analytical capabilities in support of damage tolerant design become readily apparent: (1) a theoretical basis to account for the effect of nonproportional loading (mechanical and mechanical/thermal); (2) the development of practical crack growth parameters that are applicable to thermomechanical fatigue situations; and (3) the development of crack growth models that address multiple crack failures.

Improved techniques for thermomechanical testing in support of deformation modeling

NASA Technical Reports Server (NTRS)

Castelli, Michael G.; Ellis, John R.

1992-01-01

The feasibility of generating precise thermomechanical deformation data to support constitutive model development was investigated. Here, the requirement is for experimental data that is free from anomalies caused by less than ideal equipment and procedures. A series of exploratory tests conducted on Hastelloy X showed that generally accepted techniques for strain controlled tests were lacking in at least three areas. Specifically, problems were encountered with specimen stability, thermal strain compensation, and temperature/mechanical strain phasing. The source of these difficulties was identified and improved thermomechanical testing techniques to correct them were developed. These goals were achieved by developing improved procedures for measuring and controlling thermal gradients and by designing a specimen specifically for thermomechanical testing. In addition, innovative control strategies were developed to correctly proportion and phase the thermal and mechanical components of strain. Subsequently, the improved techniques were used to generate deformation data for Hastelloy X over the temperature range, 200 to 1000 C.

Application of Thermo-Mechanical Measurements of Plastic Packages for Reliability Evaluation of PEMS

NASA Technical Reports Server (NTRS)

Sharma, Ashok K.; Teverovsky, Alexander

2004-01-01

Thermo-mechanical analysis (TMA) is typically employed for measurements of the glass transition temperature (Tg) and coefficients of thermal expansion (CTE) in molding compounds used in plastic encapsulated microcircuits (PEMs). Application of TMA measurements directly to PEMs allows anomalies to be revealed in deformation of packages with temperature, and thus indicates possible reliability concerns related to thermo-mechanical integrity and stability of the devices. In this work, temperature dependencies of package deformation were measured in several types of PEMs that failed environmental stress testing including temperature cycling, highly accelerated stress testing (HAST) in humid environments, and bum-in (BI) testing. Comparison of thermo-mechanical characteristics of packages and molding compounds in the failed parts allowed for explanation of the observed failures. The results indicate that TMA of plastic packages might be used for quality evaluation of PEMs intended for high-reliability applications.

Atomic Layer Deposition of the Solid Electrolyte LiPON

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

Kozen, Alexander C.; Pearse, Alexander J.; Lin, Chuan -Fu

We demonstrate an atomic layer deposition (ALD) process for the solid electrolyte lithium phosphorousoxynitride (LiPON) using lithium tert-butoxide (LiO tBu), H 2O, trimethylphosphate (TMP), and plasma N 2 ( PN 2) as precursors. We use in-situ spectroscopic ellipsometry to determine growth rates for process optimization to design a rational, quaternary precursor ALD process where only certain substrate–precursor chemical reactions are favorable. We demonstrate via in-situ XPS tunable nitrogen incorporation into the films by variation of the PN 2 dose and find that ALD films over approximately 4.5% nitrogen are amorphous, whereas LiPON ALD films with less than 4.5% nitrogen aremore » polycrystalline. Lastly, we characterize the ionic conductivity of the ALD films as a function of nitrogen content and demonstrate their functionality on a model battery electrode—a Si anode on a Cu current collector.« less

Atomic Layer Deposition of the Solid Electrolyte LiPON

DOE PAGES

Kozen, Alexander C.; Pearse, Alexander J.; Lin, Chuan -Fu; ...

2015-07-09

We demonstrate an atomic layer deposition (ALD) process for the solid electrolyte lithium phosphorousoxynitride (LiPON) using lithium tert-butoxide (LiO tBu), H 2O, trimethylphosphate (TMP), and plasma N 2 ( PN 2) as precursors. We use in-situ spectroscopic ellipsometry to determine growth rates for process optimization to design a rational, quaternary precursor ALD process where only certain substrate–precursor chemical reactions are favorable. We demonstrate via in-situ XPS tunable nitrogen incorporation into the films by variation of the PN 2 dose and find that ALD films over approximately 4.5% nitrogen are amorphous, whereas LiPON ALD films with less than 4.5% nitrogen aremore » polycrystalline. Lastly, we characterize the ionic conductivity of the ALD films as a function of nitrogen content and demonstrate their functionality on a model battery electrode—a Si anode on a Cu current collector.« less

Field-scale electrolysis/ceramic membrane system for the treatment of sewage from decentralized small communities.

PubMed

Son, Dong-Jin; Kim, Woo-Yeol; Yun, Chan-Young; Kim, Dae-Gun; Chang, Duk; Sunwoo, Young; Hong, Ki-Ho

2017-07-05

The electrolysis process adopting copper electrodes and ceramic membrane with pore sizes of 0.1-0.2 μm were consisted to a system for the treatment of sewage from decentralized small communities. The system was operated under an HRT of 0.1 hour, voltage of 24 V, and TMP of 0.05 MPa. The system showed average removals of organics, nitrogen, phosphorus, and solids of up to 80%, 52%, 92%, and 100%, respectively. Removal of organics and nitrogen dramatically increased in proportion to increment of influent loading. Phosphorus and solids were remarkably eliminated by both electro-coagulation and membrane filtration. The residual particulate constituents could also be removed successfully through membrane process. A system composed of electrolysis process with ceramic membrane would be a compact, reliable, and flexible option for the treatment of sewage from decentralized small communities.

Effects of pharmaceutical micropollutants on the membrane fouling of a submerged MBR treating municipal wastewater: case of continuous pollution by carbamazepine.

PubMed

Li, Chengcheng; Cabassud, Corinne; Reboul, Bernard; Guigui, Christelle

2015-02-01

Membrane bioreactor (MBR) is increasingly used for municipal wastewater treatment and reuse and great concerns have been raised to some emerging trace pollutants found in aquatic environment in the last decade, notably the pharmaceuticals. As a consequence the removal of pharmaceutical micropollutants by MBRs has been extensively investigated. But there is still a lack of knowledge on the effects of the current presence of pharmaceutical micropollutants in domestic wastewaters on MBR fouling. Among the different pharmaceuticals, it was decided to focus on carbamazepine (CBZ), an anti-epileptic drug, because of its occurrence in domestic wastewaters and persistency in biological processes including MBRs. This paper focuses on the effects of continuous carbamazepine pollution on MBR fouling. A continuous introduction of CBZ into the MBR via the feed (about 90 μg L(-1) CBZ in the feed) provoked a TMP jump. It occurred just 1 day after the addition of CBZ in MBR and a significantly higher increase rate of TMP was also observed after 1 day after addition of CBZ in MBR, as compared to that before addition of CBZ. This indicates that the pharmaceutical stress induced by CBZ causes more severe membrane fouling. Addition of CBZ was shown to induce a significant increase of the concentration of proteins in the supernatant at the beginning several days then stabilized to original level whereas no significant change was found for polysaccharides. HPLC-SEC analysis showed that addition of CBZ induced a decrease of 100-1000 kDa protein-like SMPs and a more significant increase of 10-100 kDa protein-like SMPs in the supernatant. Moreover it was found that addition of CBZ in the MBR affected the sludge microbial activities, as a slight inhibition (about 20%) of the exogenous respiration rate was observed. The increased membrane fouling could be related to the change in biomass characteristics and supernatant quality after addition of CBZ in MBR. This study allows also suggesting that 10-100 kDa protein-like SMPs might accumulate inside the biocake that was formed on the membrane surface during MBR operation and play an important role in the TMP jump phenomenon. Copyright © 2014 Elsevier Ltd. All rights reserved.