Effect of hydrogenative regeneration on the activity of beta and Pt-Beta zeolites during the transalkylation of toluene with 1,2,4-trimethylbenzene

Catalyst deactivation remains a main challenge in the transalkylation process. To develop a cost-effective catalyst, improving the regeneration characteristics of Beta and Pt-Beta catalysts was investigated. Both Beta and Pt-Beta catalysts were studied in transalkylation in the presence of hydrogen. The regeneration process was carried out using hydrogen for four cycles of operation (30 h on stream per cycle). A Pt-Beta catalyst with enhanced regeneration and activity characteristic relative to the parent materials is presented, and found to be stable, with the activity fully restored by regeneration with hydrogen at 500 °C. The activity of the parent Beta dropped gradually after each cycle suggesting that the hydrogen alone at 500 °C was insufficient in removing the coke formed during the reaction. The drop in activity was attributed to the disappearance of Brønsted acid sites over the spent Beta catalyst due to the growth of coke molecules trapped in the zeolite micropores leading to the formation of highly polyaromatic molecules blocking those active sites. This limitation can be effectively overcome by platinum addition which enhanced the removal of coke during the regeneration via hydrocracking

Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

Nienow, Sole and Cowton’s Greenland research has been supported by a number of UK NERC research grants (NER/O/S/2003/00620; NE/F021399/1; NE/H024964/1; NE/K015249/1; NE/K014609/1) and Slater has been supported by a NERC PhD studentshipPurpose of the review:  This review discusses the role that meltwater plays within the Greenland ice sheet system. The ice sheet’s hydrology is important because it affects mass balance through its impact on meltwater runoff processes and ice dynamics. The review considers recent advances in our understanding of the storage and routing of water through the supraglacial, englacial, and subglacial components of the system and their implications for the ice sheet Recent findings:   There have been dramatic increases in surface meltwater generation and runoff since the early 1990s, both due to increased air temperatures and decreasing surface albedo. Processes in the subglacial drainage system have similarities to valley glaciers and in a warming climate, the efficiency of meltwater routing to the ice sheet margin is likely to increase. The behaviour of the subglacial drainage system appears to limit the impact of increased surface melt on annual rates of ice motion, in sections of the ice sheet that terminate on land, while the large volumes of meltwater routed subglacially deliver significant volumes of sediment and nutrients to downstream ecosystems. Summary:  Considerable advances have been made recently in our understanding of Greenland ice sheet hydrology and its wider influences. Nevertheless, critical gaps persist both in our understanding of hydrology-dynamics coupling, notably at tidewater glaciers, and in runoff processes which ensure that projecting Greenland’s future mass balance remains challenging.Publisher PDFPeer reviewe

The risk of metabolic syndrome as a result of lifestyle among Ellisras rural young adults

The study aimed to investigate the association between metabolic syndrome (MetS) and lifestyle risk factors among Ellisras adults. A cross-sectional study was conducted on 624 adults (306 males and 318 females). MetS was defined according to the criteria of the International Diabetes Federation. The prevalence of MetS was 23.1% (8.6% males and 36.8 % females). Females appeared to have higher mean values for waist circumference (WC), fasting blood glucose (FBG), total cholesterol (TCHOL) and low-density lipoprotein cholesterol (LDL-C), while males had high mean values for high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), systolic blood pressure (SBP) and diastolic blood pressure (DBP). No significant age and gender differences were observed for dietary intake. Significantly more females (51.9%) presented with increased WC than males (4.6%). Participants who had a high dietary energy intake were significantly less likely to present with larger WC (OR: 0.250 95% CI [0.161; 0.389]), low HDL-C (OR: 0.306 95% CI [0.220; 0.425]) and high LDL-C (OR: 0.583 95% CI [0.418; 0.812]) but more likely to present with elevated FBG (OR: 1.01 95% CI [0.735; 1.386]), high TCHOL (OR: 1.039 95% CI [0.575; 1.337]), high TG (OR: 1.186 95% CI [0.695; 2.023]) and hypertension (OR: 5.205 95% CI [3.156; 8.585]). After adjusting for age, gender, smoking, and alcohol status, high energy intake was more than two times likely to predict MetS in adults with a large WC (OR: 2.766 95% CI [0.863; 3.477] and elevated FBG (OR: 2.227 95% CI [1.051; 3.328]). Therefore, identifying groups that are at an increased risk and those that are in their early stages of MetS will help improve and prevent the increase of the MetS in the future

Extending breastfeeding duration through primary care: a systematic review of prenatal and postnatal interventions.

This literature review provides an overview of the effectiveness of strategies and procedures used to extend breastfeeding duration. Interventions carried out during pregnancy and/or infant care conducted in primary health care services, community settings, or hospital clinics were included. Interventions covering only the delivery period were excluded. Interventions that were most effective in extending the duration of breastfeeding generally combined information, guidance, and support and were long term and intensive. During prenatal care, group education was the only effective strategy reported. Home visits used to identify mothers' concerns with breastfeeding, assist with problem solving, and involve family members in breastfeeding support were effective during the postnatal period or both periods. Individual education sessions were also effective in these periods, as was the combination of 2 or 3 of these strategies in interventions involving both periods. Strategies that had no effect were characterized by no face-to-face interaction, practices contradicting messages, or small-scale interventions