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Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Eigen G Eisenstein BI Freese T Gladding G Grab C Heusch CA Hitlin DG Izen JM Köpke L Li A Lockman WS Mallik U Matthews CG Mir R Mockett PM Mozley RF Nemati B Odian A Parker J Parrish L Partridge R Pitman D Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C Stockdale IE Stockhausen W Thaler JJ Toki W Tripsas B Villa F Wasserbaech S Wattenberg A Weinstein AJ 《Physical review letters》1987,58(21):2171-2174
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A. Sionkowska M. Wisniewski G.F. Poggi C.A. Maxwell 《Polymer Degradation and Stability》2006,91(12):3026-3032
The thermal and mechanical properties of collagen/chitosan blends before and after UV irradiation have been investigated using thermal analysis and mechanical (Instron) techniques. Comparisons were made with the thermal and mechanical properties of both collagen and chitosan films. Air-dried collagen, chitosan and collagen/chitosan films were exposed to UV irradiation (wavelength 254 nm) for different time intervals. Thermal properties of collagen/chitosan blends depend on the composition of the blend and are not significantly altered by UV irradiation.Mechanical properties such as ultimate tensile strength and ultimate percentage of elongation were much better for collagen films than for collagen/chitosan films. The results have shown that the mechanical properties of the blends were greatly affected by the duration of UV irradiation. Ultimate tensile strength and ultimate percentage elongation decreased after UV irradiation of the blend. Increasing UV irradiation leads to an increase in Young's modulus of the collagen/chitosan blend. 相似文献
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Joseph Derosa Taeho Kang Van T. Tran Dr. Steven R. Wisniewski Dr. Malkanthi K. Karunananda Tanner C. Jankins Kane L. Xu Dr. Keary M. Engle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1217-1221
A nickel-catalyzed conjunctive cross-coupling of alkenyl carboxylic acids, aryl iodides, and aryl/alkenyl boronic esters is reported. The reaction delivers the desired 1,2-diarylated and 1,2-arylalkenylated products with excellent regiocontrol. To demonstrate the synthetic utility of the method, a representative product is prepared on gram scale and then diversified to eight 1,2,3-trifunctionalized building blocks using two-electron and one-electron logic. Using this method, three routes toward bioactive molecules are improved in terms of yield and/or step count. This method represents the first example of catalytic 1,2-diarylation of an alkene directed by a native carboxylate group. 相似文献
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Joseph Derosa Taeho Kang Van T. Tran Steven R. Wisniewski Malkanthi K. Karunananda Tanner C. Jankins Kane L. Xu Keary M. Engle 《Angewandte Chemie (International ed. in English)》2020,59(3):1201-1205
A nickel‐catalyzed conjunctive cross‐coupling of alkenyl carboxylic acids, aryl iodides, and aryl/alkenyl boronic esters is reported. The reaction delivers the desired 1,2‐diarylated and 1,2‐arylalkenylated products with excellent regiocontrol. To demonstrate the synthetic utility of the method, a representative product is prepared on gram scale and then diversified to eight 1,2,3‐trifunctionalized building blocks using two‐electron and one‐electron logic. Using this method, three routes toward bioactive molecules are improved in terms of yield and/or step count. This method represents the first example of catalytic 1,2‐diarylation of an alkene directed by a native carboxylate group. 相似文献
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Baltrusaitis RM Becker JJ Blaylock GT Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Cui H Del Papa C Dorfan DE Duncan AL Einsweiler KF Eisenstein BI Fabrizio R Gladding G Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Mockett PM Moss L Mozley RF Nappi A Odian A Partridge R Perrier J Plaetzer SA Richman JD Roehrig JR Russell JJ Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Sleeman JC Spadafora AL Thaler JJ Toki W Unno Y Villa F Wattenberg A 《Physical review letters》1985,55(17):1723-1726
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Pedro Marcos Frugeri Camila Marchioni Ayla Campos do Lago Célio Wisniewski 《Analytical letters》2018,51(10):1492-1504
This work proposes a flow injection analysis system for sulfaguanidine determination in pharmaceutical and food samples. The method was based on the reaction of sulfaguanidine with nitronium ion to produce a colored complex whose absorbance was measured at 545?nm. The flow injection analysis system’s significant parameters were checked by a fractional factorial design 27–2 and optimization by a Doehlert matrix. The flow injection analysis system shows optimum values at 0.28, 2.00, and 0.11% (w/v) for N-naphtil ethylenediamine, ammonium sulfamate, and sodium nitrite concentrations, respectively. The possible interferents present in pharmaceutical and food samples were assessed by a multivariate technique and depicted on probability charts, indicating no significant interferences at the 95% level of confidence interval. The method showed detection and quantification limits of 0.012 and 0.039?mg?L?1, an analytical frequency of 30 readings h?1 and precision always lower than 5.0% expressed as the relative standard deviation. The obtained results were in accordance with those obtained by high-performance liquid chromatography. 相似文献