A review on waste management and compost production in the Middle East-North Africa region

Over the last two decades, solid waste management in the Middle East-North Africa (MENA) region has been one of the major challenges due to increasing solid waste quantities and poor waste management practices. With the tremendously increasing amounts of organic waste, MENA countries are under great pressure and are facing the threats of acute air pollution, contamination of water bodies and climate change. As a result, these countries are adopting different methods to cope with this rising challenge of waste management, including composting. This review reports on the different MENA countries' organic waste quantities, disposal methods, organic waste management practices and challenges, along with the potential use and demand of compost, where information is available. The reported data are from 2009 to 2021, with the bulk of the papers being from 2014 and onwards. The total amount of municipal waste collected in the 21 countries ranged from 0.56 million tons in Mauritania to 90 million tons in Egypt, with an average of 16.42 million tons, equivalent to 1.08 kg per capita waste generation per day. Around 55% of this material is biogenous. Many treatments and repurposing methods of this material are adopted in the MENA region, mainly through composting, as it presents one of the most sustainable solutions that lead to immediate climate change mitigation. This article also presents the biotic and abiotic stressors faced by this region, which in turn affect the successful implementation of composting solutions, and proposes some solutions based on different studies conducted.

Islet amyloid polypeptide in diabetic and non-diabetic Pima Indians

Islet amyloid may have a pathological role in the development of Type 2 (non-insulin-dependent) diabetes mellitus. The prevalence of islet amyloid has been investigated on post-mortem pancreatic tissue from both diabetic and non-diabetic Pima Indian subjects who had previously been assessed by oral glucose tolerance tests. Islets were examined for amyloid deposits and for cellular immunoreactivity to pancreatic hormones and islet amyloid polypeptide, the constituent peptide of islet amyloid. Twenty of 26 diabetic subjects (77%) had islet amyloid, compared with one of 14 non-diabetic subjects (7%). Twelve of the diabetic subjects (46%) had amyloid in more than 10% of their islets, whereas only 4% of islets were affected in a single non-diabetic subject. Positive immunoreactivity for islet amyloid peptide was present in the islet amyloid and in islet cells in 54% of the diabetic and 50% of the non-diabetic subjects. Islet amyloid in diabetic Pima Indians may indicate a primary Beta-cell defect which interacts with insulin resistance to produce diabetes, or may develop as a result of Beta-cell dysfunction induced by insulin resistance and hyperglycaemia.

Factors influencing variability in manganese content of seeds, with emphasis on barley (Hordeum vulgare) and white lupins (Lupinus albus)

Considerable variability can occur in the manganese (Mn) content and concentration of seeds. This variability can influence plant growth and development, crop yield and seed quality. In order to understand which factors affect seed Mn variability, the effects of site of growth, season and genotype on the Mn content of barley seed were examined. Plant-to-plant and within-plant variability of white lupin seed were also examined. Manganese concentrations of seeds of barley, wheat and faba bean grown at the same site were compared. For barley, site of growth was the most important determinant of Mn content of the seed. Cultivar differences were not statistically significant. There was a significant season by site interaction which indicated that season affected seed Mn content at a site with low Mn availability but not at a site with adequate Mn. Manganese concentrations in seeds of different species grown at the same site varied considerably. 'Tatiara' wheat had more than twice the Mn concentration of 'Schooner' barley (48 and 21 mg kg-1, respectively), while small-seeded faba bean had the lowest Mn concentration of the three (6 mg kg-1). In white lupin, there were significant differences in seed Mn content of plants growing side by side at the same site. Significant within-plant variation was also found for both white lupins and barley. The range of Mn concentration of seed from one plant was 1530 to 3750 mg kg-1for white lupins and 1 1 to 24 mg kg-1 for barley. In barley (and probably most plants), variability of seed Mn concentration can be minimized by selecting seed by weight from parents grown at the same site during the same season. Variability of Mn concentration and content of white lupin seeds is not as easily accounted for and thus is more difficult to minimize. For barley, there was a positive relationship between seed weight and Mn concentration (r2= 0.66), while in white lupins, no such relationship was apparent. For white lupins with high concentrations of Mn, seed Mn variability could not be accounted for by genotype or seed weight.

Relation of fasting plasma glucose concentration to plasma insulin and glucagon concentrations. Studies in latent diabetics and women who have produced large-for-dates babies

Mothers who have had gestations diabetes (latent diabetics-LD), as well as those who have produced a large-for-dates baby (LFD) but who were not known to have been diabetic, have raised fasting plasma glucose levels, and these may induce fetal overnutrition. The increased birthweight of babies of obese mothers may also be due to their raised fasting plasma glucose levels. LD and LFD have normal or raised fasting plasma insulin levels even though they have both decreased insulin secretion to small changes in plasma glucose and normal or increased insulin sensitivity. The high fasting plasma glucose probably results from the decreased insulin-secretory response to glucose. Normal subjects have little day-to-day variation of their fasting plasma glucose, whereas subjects with a high fasting plasma glucose have less precise control. Although LD and LFD had abnormal insulin responses, they have normal plasma glucagon concentrations that do not correlate with glucose tolerance or insulin sensitivity. The reported abnormalities of glucagon in diabetes are probably a secondary, not a primary event.