| 1321. |
- Philip, JosephYN, et al.
(författare)
-
Preparation of molecularly imprinted polymers using anacardic acid monomers derived from cashew nut shell liquid
- 2007
-
Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 55:22, s. 8870-8876
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to use monomers from cashew (Anacardium occidentale L.) nut shells to develop molecularly imprinted polymers. Cashew nut shell liquid (CNSL) is a cheap and renewable agro byproduct consisting of versatile monomers. Solvent-extracted CNSL contains over 80% anacardic acid (AnAc) with more than 90% degree of unsaturation in its C-15 side chain. From AnAc monomer, anacardanyl acrylate (AnAcr) and anacardanyl methacrylate (AnMcr) monomers were synthesized and their chemical structures were characterized by Fourier transform IR and NMR. Different imprinted bulk polymers based on AnAc, AnAcr, and AnMcr functional monomers have been prepared. In the present study, each functional monomer was separately copolymerized in toluene with ethylene glycol dimethacrylate and divinylbenzene as cross-linkers, using racemic propranolol as a model template. While the AnAc based polymer revealed a meager rebinding ability, the imprinted polymers made from AnAcr and AnMcr displayed highly specific propranolol binding. At a polymer concentration of 2 mg/mL, AnAcr and AnMcr based imprinted polymers were able to bind over 50% of trace propranolol (initial concentration 1.2 nM). Under the same condition propranolol uptake by the two nonimprinted control polymers was less than 20%. Chiral recognition properties of these polymers were further confirmed using tritium-labeled (S)-propranolol as a tracer in displacement experiments, suggesting that the apparent affinity of the imprinted chiral sites for the correct enantiomer is at least 10 times that of the mismatched (R)-propranolol. Moreover, cross reactivity studies of these polymers showed that the (S)-imprinted sites have higher cross-reactivity toward (R,S)metoprolol than (R)-propranolol and (R)-timolol.
|
|
| 1322. |
- Porat, Gil, et al.
(författare)
-
Phase-matched extreme-ultraviolet frequency-comb generation
- 2018
-
Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 12:7, s. 387-391
-
Tidskriftsartikel (refereegranskat)abstract
- Laser-driven high-order harmonic generation1,2 provides spatially3 and temporally4 coherent tabletop sources of broadband extreme-ultraviolet (XUV) light. These sources typically operate at low repetition rates, frep ≲ 100 kHz, where phase-matched HHG is readily achieved5,6. However, many applications demand the improved counting statistics or frequency-comb precision afforded by high repetition rates, frep > 10 MHz. Unfortunately, at such high frep, phase matching is prevented by steady-state plasma accumulated in the generation volume7–11, strongly limiting the XUV average power. Here, we use high-temperature gas mixtures as the generation medium to increase the gas translational velocity, thereby reducing the steady-state plasma in the laser focus. This allows phase-matched XUV emission inside a femtosecond enhancement cavity at frep = 77 MHz, enabling a record generated power of ~ 2 mW in a single harmonic order. This power scaling opens up many demanding applications, including XUV frequency-comb spectroscopy12,13 of few-electron atoms and ions for precision tests of fundamental physical laws and constants14–20.
|
|
| 1323. |
- Porat, G., et al.
(författare)
-
Phase-matched extreme-ultraviolet frequency-comb generation
- 2019
-
Ingår i: Ultrafast Optics XII. - 1996-756X .- 0277-786X. - 9781510635128 ; 11370, s. 94-95
-
Konferensbidrag (refereegranskat)abstract
- Extreme ultraviolet (XUV) laser radiation is commonly produced via high-harmonic generation (HHG) in gases. The lasers that drive this process typically operate at low pulse repetition rates (<100 kHz). Under these operating conditions, the plasma generated by each laser pulse clears the generation volume before the next pulse arrives. Therefore, each laser pulse interacts with fresh plasma-free gas, where phase-matching facilitates efficient HHG. However, applications requiring high counting statistics or frequency-comb precision make high repetition rates (>10 MHz) necessary. Unfortunately, at high repetition rates, plasma accumulates in the XUV generation region and prevents phase-matching, resulting in low HHG efficiency. We use high-temperature gas mixtures to increase the gas translational velocity, thus reduce plasma accumulation and facilitate phase-matching. We experimentally achieve phase-matched HHG at a repetition rate of 77 MHz, generating record power of ~2 mW at 97 nm and ~0.9 mW at 67 nm.
|
|
| 1324. |
- Rahnev, D, et al.
(författare)
-
The Confidence Database
- 2020
-
Ingår i: Nature human behaviour. - : Springer Science and Business Media LLC. - 2397-3374. ; 4:3, s. 317-325
-
Tidskriftsartikel (refereegranskat)
|
|
| 1325. |
- Ramström, O., et al.
(författare)
-
Applications of molecularly imprinted materials as selective adsorbents : Emphasis on enzymatic equilibrium shifting and library screening
- 1998
-
Ingår i: Chromatographia. - 0009-5893. ; 47:7-8, s. 465-469
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular imprinting is an attractive method for producing highly selective adsorbents, and several new and potentially useful applications based on molecularly imprinted polymers (MIPs) have been described in recent years. In this article, we highlight some of the areas where these materials have found application, and also describe some new fields of application where the selectivities of imprinted materials can be gainfully employed, for example as binding matrices in the screening of combinatorial libraries, and as auxiliary agents in enzymatic syntheses.
|
|
| 1326. |
- Ramström, O., et al.
(författare)
-
Chiral recognition by molecularly imprinted polymers in aqueous media
- 1998
-
Ingår i: Chromatographia. - 0009-5893. ; 48:3-4, s. 197-202
-
Tidskriftsartikel (refereegranskat)abstract
- Molecularly imprinted polymers were prepared using 2-vinylpyridine and/or methacrylic acid as functional monomers in a self-assembly imprinting protocol. The resulting polymers were analyzed in aqueous media, and the effects from the pH of the mobile phase and the degree of added organic solvent were investigated. The results are indicative of the importance of ionic bonds in conjunction with hydrophobic interactions in the formation of the complexes between the analyte and the polymers.
|
|
| 1327. |
|
|
| 1328. |
- Rohrmann, Sabine, et al.
(författare)
-
Meat and fish consumption and risk of pancreatic cancer: Results from the European Prospective Investigation into Cancer and Nutrition
- 2013
-
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 132:3, s. 617-24
-
Tidskriftsartikel (refereegranskat)abstract
- Pancreatic cancer is the fourth most common cause of cancer death worldwide with large geographical variation, which implies the contribution of diet and lifestyle in its etiology. We examined the association of meat and fish consumption with risk of pancreatic cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC). A total of 477,202 EPIC participants from 10 European countries recruited between 1992 and 2000 were included in our analysis. Until 2008, 865 nonendocrine pancreatic cancer cases have been observed. Calibrated relative risks (RRs) and 95% confidence intervals (CIs) were computed using multivariable-adjusted Cox hazard regression models. The consumption of red meat (RR per 50 g increase per day = 1.03, 95% CI = 0.931.14) and processed meat (RR per 50 g increase per day = 0.93, 95% CI = 0.711.23) were not associated with an increased pancreatic cancer risk. Poultry consumption tended to be associated with an increased pancreatic cancer risk (RR per 50 g increase per day = 1.72, 95% CI = 1.042.84); however, there was no association with fish consumption (RR per 50 g increase per day = 1.22, 95% CI = 0.921.62). Our results do not support the conclusion of the World Cancer Research Fund that red or processed meat consumption may possibly increase the risk of pancreatic cancer. The positive association of poultry consumption with pancreatic cancer might be a chance finding as it contradicts most previous findings.
|
|
| 1329. |
- Rota, M, et al.
(författare)
-
Erratum
- 2018
-
Ingår i: International journal of cancer. - : Wiley. - 1097-0215 .- 0020-7136. ; 143:8, s. E10-E10
-
Tidskriftsartikel (refereegranskat)
|
|
| 1330. |
- Satwara, Maulik, 1990, et al.
(författare)
-
Finite element analysis of bond line thickness and fiber distribution in solder based thermal interface materials
- 2017
-
Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 167-171
-
Konferensbidrag (refereegranskat)abstract
- As microelectronic devices continue to decrease in size, failure of these devices is commonly attributed to ineffectual thermal management. Hence, increased thermal failures at elevated temperature has accounted for some of their reliability concerns and expected to be a major bottleneck for future development of microelectronics. For the thermal management, solder based materials give a better performance as thermal interface materials (TIM). However, these materials have a marginal reliability due to their higher Young's modulus. Therefore new type of solder based nano polymer composite (SMNPC) material is introduced. The SMNPC is composed of Sn-Ag-Cu (SAC) infiltrated through a silver coated PA6, 6 polymer fiber mesh to address electrical, thermal and mechanical challenges. In this work, finite element modeling was employed to investigate the thermal and mechanical properties of the composite material by varying polymer distribution, total volume of polymer and bond fine thickness (BLT). The composite is demonstrated to possess high heat transfer capability and lower elastic modulus as shown in Figure 1. All the results demonstrate that the developed SMNPC is proved a good alternative for conventional TIMs to improve thermal and mechanical properties.
|
|
