Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence

Pyrene excimer fluorescence (PEF) was used to investigate the effects that the presence of low molecular weight oligo(n-butyl methacrylate) (OBMA) have on the diffusion of high molecular weight poly(n-butyl methacrylate) (PBMA) in latex films. In this project, a high molecular weight PBMA latex labeled with 1.9 mol% pyrene (Py-PBMA, Mw = 410 kg/mol, PDI = 2.0) was mixed with nine non-fluorescent latex particles which needed to be prepared. Among these nine particles, two unlabeled latexes (Mw = 360 kg/mol, PDI = 1.8 and Mw = 420 kg/mol, PDI = 1.9) were prepared without oligomers. Their molecular weight distribution (MWD) was slightly different from that of Py-PBMA. Four latex dispersions that incorporated four different weight fractions of an OBMA with an Mn of 3.0 kg/mol were prepared from a PBMA seed latex, whose MWD (Mw = 350 kg/mol, PDI = 1.9) was close to one of the unlabeled latex particles prepared without OBMA. Three more latex dispersions with three weight fractions of OBMAs with an Mn of 5.0 kg/mol were prepared from a PBMA seed latex, whose MWD (Mw = 460 kg/mol, PDI = 2.4) was similar to the other unlabeled latex polymerized without OBMA. Several blends of latex particles constituted of 5 wt% of Py-PBMA and 95 wt% of the non-fluorescent PBMA latex with or without oligomers were prepared and latex films were cast from these mixtures. The films were annealed at different temperatures and the fluorescence spectra of the films were acquired as a function of annealing time. They were analyzed to retrieve the fraction of mixing (fm), representing the molar fraction of Py-PBMA chains having diffused out of the Py-PBMA latex. In turn, the diffusion coefficients reflecting the diffusion of the polymer chains during film annealing were calculated from the fm values at each temperature and for different annealing times. Diffusion of the Py-PBMA chains was much enhanced upon mixing the Py-PBMA latex with the PBMA latex that contained a larger weight fraction of a same OBMA or a shorter OBMA at a same weight fraction. Master curves of the diffusion coefficient as a function of fm could be generated by determining the shift factors (aT). A plot of Ln(aT)-vs-1/T yielded the activation energy for the diffusion of the Py-PBMA chains, which was found to equal 163 ± 9 kJ/mol, regardless of the OBMA content or chain length. The efficiency (β) of OBMA as a plasticizer was determined as a function of oligomer length using the Fujita-Doolittle model. In addition, the temperature dependence of the efficiency was studied. The results showed that the plasticizer efficiency of the 3.0 kg/mol oligomer was larger than that of the 5.0 kg/mol at all temperatures studied, but that the difference in plasticizer efficiency between the two oligomers decreased for decreasing temperatures. The higher plasticizer efficiency of the 3.0 kg/mol oligomer was confirmed from a plot of Tg as a function of oligomer weight fraction, showing that Tg decreased more markedly with the 3.0 rather than the 5.0 kg/mol oligomer. In summary, this project further demonstrated the validity and robustness of the procedure based on pyrene excimer formation (PEF) to probe polymer chain diffusion in latex films

Board Gender Diversity and Dividend Policy in SMEs: Moderating Role of Capital Structure in Emerging Market

Given the mix findings in literature regarding gender diversity and dividend policy, we suspected that capital structure is an intervening variable to moderate the relationship.  This paper therefore examines the joint role of board gender diversity and capital structure of a firm; does it improve or weaken dividend policy. The study analyzed 2015 year data from 1,011 unlisted firms from Ghana. Structured questionnaire and published annual reports were used to obtain the required data for the study. The results indicate that the relationship between the interaction term and dividend policy is insignificant, hence capital structure does not moderate the relationship between board gender diversity and dividend policy. Policy makers should not blindly adopt initiative of gender equality from another country; instead they should carefully examine the influence of capital structure and the causality of relation before appointing more or less of females on corporate boards

Štiri predavanja o estetiki

-

Conceptualizing Employee Empowerment through Flexible Working

This paper analysis and reports the empowerment through flexible working options in organizations.  Paper examines the relationship between flexible working schedules and empowerment among employees, looks at how flexible working are source of empowerment. Empowering employees to participate in organizational decision making and their day to day activities can improve organizations performance, quality and quantity of work, team working, Job satisfaction and reduce turnover. Flexible working improves the life and well-being of employees as Flexible working provides opportunity to make their working schedules.  Any form of empowerment results in taking on workers more responsibilities and flexible working is one of the intentions of empowerment and encouragements. In many organizations managers and owners are trying to answer a question how to empower the employees. Flexible working is the most common and powerful tool through which managers can empower the employees within organizations.  This paper concludes how different flexible working options might have effect on employee empowerment. Access to flexible working is the key to empowerment, self-confident and dignity of the employees. Keywords: Flexible Working, Empowerment, Employee

Are Flexible Workings Highly Gendered with More Women Availing Benefits than Men?

This paper examines the degree of relevance of various flexible options and various benefits of flexible working for men and women. Men and women workers have equal access to flexible working and avail equally various arrangements like job sharing, working from home, part time etc. In this paper, we discuss the impact of flexible working arrangements on both men and women workers’ career, social life, attitude and balance. The Flexible workings are not highly gendered with more women availing options and benefits than men. Flexible workings do not treat a man differently than the way these treat a woman. The male employees are confused only because of lack of awareness about flexible working and need to avail the options. Moreover, paper discusses various benefits of availing flexible workings for organization itself, men, and women; and also sheds light on men and women uptakes of flexible workings options. These different options may have different preferences based on gender. This paper suggests that if the gender gap to be closed, organizations must allow greater flexible schedules at workplaces for both men and women. Flexible workings are neither a zero sum game in which men gains and women lose; nor gendered only by availing opportunities for women. Both men and women are attracted to jobs with flexible working options. Flexible workings allow individuals to make balance; both men and women enjoy flexible workings benefits. Keywords: Flexible working, Gender, availing benefits

Genome-wide identification, phylogenetic and expression analysis of the heat shock transcription factor family in bread wheat (Triticum aestivum L.)

BackgroundEnvironmental toxicity from non-essential heavy metals such as cadmium (Cd), which is released from human activities and other environmental causes, is rapidly increasing. Wheat can accumulate high levels of Cd in edible tissues, which poses a major hazard to human health. It has been reported that heat shock transcription factor A 4a (HsfA4a) of wheat and rice conferred Cd tolerance by upregulating metallothionein gene expression. However, genome-wide identification, classification, and comparative analysis of the Hsf family in wheat is lacking. Further, because of the promising role of Hsf genes in Cd tolerance, there is need for an understanding of the expression of this family and their functions on wheat under Cd stress. Therefore, here we identify the wheat TaHsf family and to begin to understand the molecular mechanisms mediated by the Hsf family under Cd stress.ResultsWe first identified 78 putative Hsf homologs using the latest available wheat genome information, of which 38 belonged to class A, 16 to class B and 24 to class C subfamily. Then, we determined chromosome localizations, gene structures, conserved protein motifs, and phylogenetic relationships of these TaHsfs. Using RNA sequencing data over the course of development, we surveyed expression profiles of these TaHsfs during development and under different abiotic stresses to characterise the regulatory network of this family. Finally, we selected 13 TaHsf genes for expression level verification under Cd stress using qRT-PCR.ConclusionsTo our knowledge, this is the first report of the genome organization, evolutionary features and expression profiles of the wheat Hsf gene family. This work therefore lays the foundation for targeted functional analysis of wheat Hsf genes, and contributes to a better understanding of the roles and regulatory mechanism of wheat Hsfs under Cd stress

Ipilimumab for the treatment of advanced melanoma in six kidney transplant patients

Immune checkpoint inhibitors are new therapeutic options for metastatic melanoma, but few data are available in organ transplant recipient populations. Six French patients, three men and three women, mean age 66 years (range 44-74), all kidney transplant recipients, received ipilimumab (CTLA-4 inhibitor) for metastatic melanoma. At diagnosis of advanced melanoma, immunosuppressive therapy had been minimized in all but one. Adverse effects included one case of grade 1 diarrhea and one of grade 1 pruritus. One patient had acute T cell-mediated rejection confirmed by histology after the first injection of ipilimumab. After a median follow-up of 4.5 (3-20) months, one patient achieved partial response, one had stable disease, and four had disease progression. All the patients died, five from melanoma, one from another cause. In this series and in the literature, ipilimumab proved to be safe and possibly active. The acute rejection we encountered was probably related to both a rapid, drastic reduction of immunosuppression and the use of ipilimumab. Our safety data on ipilimumab contrast with the organ transplant rejections already reported with PD-1 inhibitors. We consider that immunosuppression should not be minimized, as the impact on metastatic disease control is probably small

Research on dual lateral log simulation of shale bedding fractures under different influencing conditions

Micro scale fractures play a crucial role in facilitating the migration of oil and gas in low permeability shale reservoirs. However, the identification of such fractures is a complex task. The efficacy of the dual lateral log physical field changes as a means of identifying shale micro fractures remains uncertain. To address this issue, a three-layer shale bedding fracture model was developed using the finite element method and core and conventional logging data from eight wells, which was based on different shale reservoirs within the Yanchang Formation in the Ordos Basin. The present study examines the dual lateral log response characteristics resulting from distinct characteristics of horizontal bedding fractures, with a focus on the response mechanism. The simulation of logging response characteristics of shale and siltstone combination were utilized by core statistical data for verification purposes. The results indicate that under the lithology combination of shale and siltstone, the magnitude of the difference between the resistivity of the filled fracture and the formation resistivity, the greater the formation resistivity of the shale itself, the wider the fracture width, and the greater the difference between the apparent resistivity and the real formation resistivity. Furthermore, the suitable conditions for the detection of shale bedding fracture characteristics by dual lateral log are clarified. In the presence of effective filling, the dual lateral log has the capability to identify shale fractures at the micron scale. The findings of our study establish a theoretical framework for the identification and assessment of shale fractures, and furnish technical assistance for the optimal selection of “sweet spots” within shale reservoirs and the precise evaluation of reservoirs. This study lays a theoretical foundation for the identification and evaluation of shale fractures, and provides technical support for the optimal “sweet spot” selection of shale reservoirs and the accurate evaluation of reservoirs