A Review of Enzymatic Transesterification of Microalgal Oil-Based Biodiesel Using Supercritical Technology

Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO2) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO2 as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO2 allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO2 as an extraction solvent and reaction media

Klason Method: An Effective Method for Isolation of Lignin Fractions from Date Palm Biomass Waste

Klason lignin extraction method is one of the robust techniques for isolation of lignin from lignocellulosic palm biomass waste for future production of High Value Chemicals (HVCs). To elucidate the mechanism of hemicellulose and cellulose glycosidic bond distraction, lignocellulos

Estimating Combustion Kinetics of UAE Date Palm tree Biomass using Thermogravimetric Analysis

Palm tree consists of different parts among which are the leaflet, rachis and fibers. All these parts constitute lignocellulose biomass components capable of producing value added end products. A kinetic study of thermal decomposition of UAE date palm tree of phoenix dicteylifera species was carried out using thermal gravimetric analysis (TGA) at heating rates 10 oC/min, 15 oC/min and 20 oC/min. Most of the lignocellulose material decomposed between 300 oC and 650 oC at each heating rate. The rachis decomposed in three phases while the leaflet and fibers decomposed in two phases. The apparent activation energies increased from 54 to 476 kJ/mol, 55 to 458 kJ/mol and 84 to 329 kJ/mol for leaflet, rachis and fibers, respectively for conversion ranging from 10-% to 80-%. Results from this study are fundamental in optimizing operational conditions of a reactor for production of furfural, levulunic acid, dihydroeugenol, DHE and 2,6-dimethoxy-4-propyl phenol, DMPP as high value chemicals. Key words: UAE Palm tree biomass, Thermogravimetric analysis, Combustion kinetics, Activation energ

Impact of the Coronavirus Pandemic (COVID-19) Lockdown on Mental Health and Well-Being in the United Arab Emirates

United Arab Emirates (UAE) has taken unprecedented precautionary measures including complete lockdowns against COVID-19 to control its spread and ensure the well-being of individuals. This study investigated the impact of COVID-19 and societal lockdown measures on the mental health of adults in the UAE. A cross-sectional study was conducted using an English and Arabic online questionnaire between May and June 2020. The psychological impact was assessed by the Impact of Event Scale-Revised (IES-R), and the social and family support impact was evaluated using questions from the Perceived Support Scale (PSS). A total of 4,426 participants (3,325 females and 1,101 males) completed the questionnaire. The mean IES-R score was 28.0 ± 14.6, reflecting a mild stressful impact with 27.3% reporting severe psychological impact. Over 36% reported increased stress from work, home and financial matters. Also, 43–63% of the participants felt horrified, apprehensive or helpless due to COVID-19. Females, younger participants, part-timers, and college or University graduates were more likely to have a high IES-R score (p \u3c 0.05). The majority of participants reported receiving increased support from family members, paying more attention to their mental health, and spending more time to rest and relax. The results of this study demonstrate the impact of the COVID-19 pandemic on mental health among the UAE residents and highlight the need to adopt culturally appropriate interventions for the general population and vulnerable groups, such as females and younger adults

Eating habits and lifestyle during covid-19 lockdown in the united arab emirates: A cross-sectional study

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The coronavirus disease is still spreading in the United Arab Emirates (UAE) with subsequent lockdowns and social distancing measures being enforced by the government. The purpose of this study was to assess the effect of the lockdown on eating habits and lifestyle behaviors among residents of the UAE. A cross-sectional study among adults in the UAE was conducted using an online questionnaire between April and May 2020. A total of 1012 subjects participated in the study. During the pandemic, 31% reported weight gain and 72.2% had less than eight cups of water per day. Furthermore, the dietary habits of the participants were distanced from the Mediterranean diet principles and closer to “unhealthy” dietary patterns. Moreover, 38.5% did not engage in physical activity and 36.2% spent over five hours per day on screens for entertainment. A significantly higher percentage of participants reported physical exhaustion, emotional exhaustion, irritability, and tension “all the time” during the pandemic compared to before the pandemic (p \u3c 0.001). Sleep disturbances were prevalent among 60.8% of the participants during the pandemic. Although lockdowns are an important safety measure to protect public health, results indicate that they might cause a variety of lifestyle changes, physical inactivity, and psychological problems among adults in the UAE

Assessment of Eating Habits and Lifestyle during Coronavirus Pandemic in the MENA region: A Cross-Sectional Study

© The Authors 2020. The coronavirus disease (COVID-19) has rapidly spread globally, forcing countries to apply lockdowns and strict social distancing measures. The aim of this study was to assess eating habits and lifestyle behaviors among residents of the Middle East and North Africa (MENA) region during the lockdown. A cross-sectional study among adult residents of the MENA region was conducted using an online questionnaire designed on Google Forms during April 2020. A total of 2970 participants from 18 countries participated in the current study. During the pandemic, over 30% reported weight gain, 6.2% consumed five or more meals per day compared to 2.2% before the pandemic (p\u3c0.001), and 48.8% did not consume fruits on daily basis. Moreover, 39.1% did not engage in physical activity, over 35% spent more than five hours per day on screens. A significant association between the frequency of training during the pandemic and the reported change in weight was found (p \u3c 0.001). A significantly higher percentage of participants reported physical and emotional exhaustion, irritability, and tension either all the time or a large part of the time during the pandemic (p \u3c 0.001). Although a high percentage of participants reported sleeping more hours per night during the pandemic, 63% had sleep disturbances. The study highlights that the lockdown due to the COVID-19 pandemic caused a variety of lifestyle changes, physical inactivity, and psychological problems among adults in the MENA region

ASIMETRIJA ŠIRINE I DUŽINE OTOLITA ODRASLIH TELEOSTIDA (Beryx splendens LOWE, 1834) (PORODICA:BERCIDAE) ULOVLJENIH UZ OBALU ARAPSKOG MORA U OMANU

Fluctuating asymmetry was described for the otolith width and length of adult teleost Beryx splendens. The results showed that the level of asymmetry of the otolith width was the highest among the two asymmetry values obtained for the otolith of B. splendens. For the otolith width character, the results showed that the level of asymmetry at its highest value in fish ranging in length between 191–200 mm and in its lowest value in fish ranging in length between 121–180 mm. For the otolith length, the highest value of asymmetry is noticed in fish ranging in length between 231–244 mm and the lowest value in fish within the length of 121–190 mm. The possible cause of the asymmetry in this species has been discussed in relation to different pollutants and their presence in the area. No trend of increase in the asymmetry values with the fish length was noticed for the otolith width, but there is a weak trend of increase with the fish length in case of otolith length character.U radu je prikazana promjena asimetrije širine i dužine otolita odraslih primjeraka Beryx splendens. Dobiveni rezultati pokazuju da su vrijednosti asimetrije širine bile više u riba koje su bile duge između 191 i 200 mm, a kod riba dužine između 121 i 180 mm vrijednosti su bile niže. Vrijednosti dužina otolita bile su više u riba dugih između 231 i 244 mm, a u riba dužine između 121 i 190 mm vrijednosti bile su niže. Mogući uzrok spomenute asimetrije razmatran je u odnosu na različite onečišćivače i njihovu prisutnost u tom području. Nije primijećeno povećanje vrijednosti asimerije širine otolita s obzirom na dužinu riba, ali je zapaženo slabo povećanje vrijednosti dužine otolita u odnosu na veličinu riba