New perylene derivative dyes for dye-sensitized solar cells

We have studied the influence of the spacer alkyl chain length of perylenemonoimide (PMI) dyes on the device performance in dye-sensitized solar cells (DSSCs). We observed that the dyes with longer and brunched alkyl chains exhibit higher efficiencies in DSSCs. In line with these statements we now report the highest efficiency obtained under standard conditions for a perylene imide derivative with PMI-DA1 that performs 300 mV open circuit voltage, 9.79 mA/cm² short-circuit current and 1.61% overall conversion efficiency.     

Methodological Challenges in Union Commitment Studies.

Methodological problems in studies of union commitment were identified and illustrated with data from 4,641 members and 479 stewards in 297 local teachers' unions. Using a 20-item union commitment scale, results confirmed the existence of 3 substantive factors and 1 method factor at the individual level of analysis: loyalty to the union, responsibility to the union, willingness to work for the union, and a factor of negatively worded items. Tests of measurement invariance showed that the scale captured commitment for rank-and-file members but not for union stewards. The authors also found partial measurement invariance between long-time and newer members and full measurement invariance between men and women. Finally, the authors found that violation of the statistical assumption of independence reduced model fit when individual commitment scores were analyzed without attention to the hierarchical nature of the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effects of Different Gums and Their Interactions on the Rheological Properties of a Dairy Dessert: A Mixture Design Approach

In this study, the steady and dynamic rheological properties of the dairy dessert samples (puddings) containing carrageenan, alginate, guar and xanthan gums and their combinations were investigated in a model system, and mixture design was utilized to observe the effects of the gums and their interactions. The flow behaviour of the pudding samples fitted to the Ostwald de Waele model (R ²?>?0.98). All the samples exhibited a gel structure with their higher G′ (storage modulus) values than the G″ (loss modulus) values. Carrageenan was the most effective hydrocolloid on both the steady and dynamic rheological parameters of the dairy dessert samples. On the other hand, alginate had relatively smaller effect. Furthermore, 30 pudding samples containing different gum or gum combinations were classified into two groups (A and B) by using principal component analysis (PCA). Samples containing more than 33% carrageenan in their formulations made up the group A which positively correlated to K (consistency index), η ₅₀ (apparent viscosity at shear rate 50 s^?1), G′, G″, G* (complex modulus) and η* (complex viscosity) values.     

Changes in the texture,physicochemical properties and volatile compound profiles of fresh Kashar cheese (<90 days) during ripening

In this study, four different fresh Kashar cheese samples were ripened for 90 days. The physicochemical properties, texture attributes, fatty acid composition and volatile compound profiles of the samples were measured every 30 days of ripening. The texture properties of the cheese samples were significantly affected by the duration of the ripening period. The results of this study highlighted that texture parameters as a function of ripening period should be considered for both fresh and aged Kashar cheeses to determine the ripening period as they are very important for consumer acceptability and consumption of the end product.     

Combination of the Simple Additive (SAW) Approach and Mixture Design to Determine Optimum Cocoa Combination of the Hot Chocolate Beverage

Physicochemical (pH, brix, and color), sensory (color, taste, odor, mouthfeeling, consistency, bitter flavor, and general acceptability), and rheological properties of the hot chocolate beverages including different cocoa combinations were investigated in the present study. Cocoa type significantly affected all of the properties. Simple additive weighting approach was applied to obtain one score from seven different sensory parameters and simple additive weighting score was used in mixture design to determine optimum cocoa type or cocoa combination. Ostwald de Waele model described the flow behavior of the hot chocolate beverage samples with R² values ranged between 0.818 and 0.999. The consistency coefficient (K) and apparent viscosity at shear rate 50 s^?1 (η₅₀) were significantly affected by cocoa type found in the formulation of the beverage. The mixture design approach was performed in order to determine variation of the responses (physicochemical, sensory, and rheological parameters) as a function of cocoa concentration. Simple additive weighting scores were satisfactorily described by established equation as a function of cocoa concentration to be used in the formulation of the hot chocolate beverage (R² = 0.8645).     

Mn~(2+)-H_2O_2-PAR分光光度法测定羟自由基及抗坏血酸抗氧化活性的比较

提出Mn~(2+)-H_2O_2-PAR[4-(2-吡啶偶氮)-间苯二酚]新体系并用于羟自由基的检测。pH 10的硼砂-氢氧化钠缓冲溶液中Mn~(2+)-H_2O_2体系产生羟自由基,加入偶氮染料PAR,羟自由基迅速氧化PAR-Mn~(2+)螯合物分解退色,测定500nm处吸光度的变化确定羟自由基产生的量。利用所建立的实验方法对抗坏血酸清除羟自由基的能力进行测定,其结果与DPPH·(二苯代苦味肼基自由基)分光光度法和羟自由基测定试剂盒法相比。结果表明:该方法稳定性好,操作简便,测定快速,重现性稳定,相对标准偏差为1.42%,可作为一种简便的筛选抗氧化剂的方法。3种方法中抗坏血酸的IC_(50)分别为0.013、0.005、0.2 mg/mL。