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Messenger RNA (mRNA) recently emerged as an appealing alternative to treat and prevent diseases ranging from cancer and Alzheimer's disease to COVID-19 with significant clinical outputs. The in vitro-transcribed mRNA has been engineered to mimic the structure of natural mRNA for vaccination, cancer immunotherapy and protein replacement therapy. In past decades, significant progress has been noticed in unveiling the molecular pathways of mRNA, controlling its translatability and stability, and its evolutionary defense mechanism. However, numerous unsolved structural, biological, and technical difficulties hamper the successful implementation of systemic delivery of mRNA for safer human consumption. Advances in designing and manufacturing mRNA and selecting innovative delivery vehicles are mandatory to address the unresolved issues and achieve the full potential of mRNA drugs. Despite the substantial efforts made to improve the intracellular delivery of mRNA drugs, challenges associated with diverse applications in different routes still exist. This study examines the current progress of mRNA therapeutics and advancements in designing biomaterials and delivery strategies, the existing translational challenges of clinical tractability and the prospects of overcoming any challenges related to mRNA.

Capillary barriers (CBs) as engineered porous composites is novel and promising technology for mitigating salinity and drought stress of plants. This study aimed to imitate a naturally formed CB structure recently discovered in the reservoir bed of Al-Khoud dam at the Governorate of Muscat in northern Oman and to test the impact of this unique CB on mitigating the salinity stress of marigold plants grown under an open field condition. A plot was constructed and divided into “structured” (engineered cascade CB design) and “unstructured” soils and planted with marigold (Tagetes erecta) plants that were subjected to four salinity treatments (control with ECi ≈ 0.6 dS m-1 ; 3 dS m-1; 6 dS m-1; and 9 dS m-1). Plant physiological, vegetative, and reproductive growth parameters were measured in each treatment. The results showed that the structured soil significantly saved irrigation water and reduce salts accumulation. Structured soil improved all vegetative and reproductive plant parameters measured and helped in reducing the effects of salinity stress on the growth and production of the marigold under arid-climate field conditions. The results also showed the capability of structured soil in water saving and improving water use efficiency. This study substantiates a novel method in mitigating salinity problem and in water saving in arid and semi-arid regions, in particular in Oman. Further studies are required to test the use of the engineered cascade CB design with different crops and with alternative (e.g. subsurface) irrigation methods.

New water-conserving irrigation technologies are vital in arid countries. We investigated the effects of (i) soil substrates made of Smart Capillary Barrier Wick (SCB-W), consisting of silt loam blocks surrounded by sand-sheathes and irrigated with a sand wick cylinder (WC) as compared to a control (homogenous soil irrigated by the same wick system, HW), (ii) WC diameters (2.54 cm vs. 1.27 cm), and (iii) 2-cm sand mulch layer on soil–water dynamics during wetting–drying cycles. Field experiments with pots and HYDRUS (2D/3D) modeling were performed in two consecutive phases (with and without sand mulch). Analysis of variance at p

Intertidal sediments host many biogeochemical processes which drastically affect coastal ecosystems. Dissolved Oxygen (DO) plays a major role in many of these biogeochemical reactions, and is of primary importance for intertidal groundwater quality. Groundwater level of intertidal zone fluctuates regularly corresponding to the tidal cycle. During the fluctuation of water table, the oxygen-rich air could be entrapped in the pore space of sediments, and hence serve as an important oxygen source to replenish oxygen-depleted groundwater. Although oxygenation enhanced by fluctuated water table has been studied in river banks, no study has been conducted in ocean intertidal sediments under tide-induced groundwater table fluctuations, and quantification of interphase oxygen mass transfer is lacking. In this study, combined laboratory experimental and numerical modeling approach is developed to study the mechanism of oxygenation of aquifers with regularly fluctuated water table. Two column experiments are conducted with regular multiple drainage-imbibition periods to mimic the Oman sea tidal cycles controlled by 3.5 and 5.75 mL/min of pumping rate respectively. The numerical model is developed and calibrated by the column experiment data, and used to simulate two additional columns by increasing the entrapped air saturation to 0.25 from 0.15 and using 30 ppt of saline water respectively. The results suggest that the larger water table fluctuation leads to 35% more dissolved oxygen, and higher entrapped air saturation enables 22% more oxygen transferred to the anoxic aqueous phase and significantly enhanced the oxygenation of the aquifer, especially the deep zone below the water table. Dissolved oxygen is 4.81% less in the column with 30 ppt of saline water than with fresh water.

Channels are widely used for conveying natural flash floods or managed aquifer recharge (MAR) released treated wastewater. Adequate models are needed for describing the interaction between hydraulics of surface flow downslope the channel and vertical seepage into a porous bed for evaluation of the depth of water and the length to which surface water “jet” propagates over a porous bed. Experiments with surface “jets” (consumed by bed infiltration) are compared with numerical and analytical modeling of these coupled flows. In the field (Al-Hail site, Oman), at a pedestal and slope of a dune, two rectangular trenches had a sand bed and a mild and steep slope S (3° and 25°, correspondingly). After applying constant discharges at the inlet of the trenches, the length, L, of the water “jets” propagating until complete extinction has been measured. The wetting front into the subjacent sand has been detected by measuring the volumetric soil moisture content at different depths in an excavation, immediately after termination of discharging the surface water. Analytically (by the hodograph method), 2-D steady phreatic seepage flow from a rectangular channel was examined as a special case of Vedernikov's solution for a soil without capillarity. Since the depth of water was small, the Riesenkampf analytical solution, involving capillarity in the tension-saturated flanks of the channel, has been also utilized. Numerically, Richard's equation has been solved by a finite element method, HYDRUS2D for arbitrary soils. The boundary condition was a hydrostatic pressure head along the wetted perimeters of the channels with water depth gradually dropping downslope. Coupling of surface and subsurface flows has been done by the “kinematic waves” approximation with Manning's friction slope equal to S. In the ODE for conservation of mass, the sink term (infiltration) was computed by either HYDRUS or analytical solution. The corresponding boundary value problem was solved by computer algebra routines.

Infiltration into a two-layered soil (continuum scale) is studied by the Green–Ampt (GA) model where the rate of infiltration (wetting front propagation) is a non-monotonic and discontinuous function of time. Both a constant ponding depth and a ponding level falling due to evaporation and infiltration are studied theoretically and in column experiments. The triads of saturated conductivity, porosity and front pressure in the two zones, as well as gravity, control vertical infiltration. Another model on the scale of a straight cylindrical capillary uses the Averyanov regime of a film flow, modified to include a front which is a quarter of a torus, rather than a spherical cap in a standard Washburn–Lukas model. The rate of front propagation is controlled by the Newtonian viscosity, tube-film sizes, surface tension, contact angle and gravity. For both scales, Cauchy problems for ODEs with respect to the front position are solved by computer algebra integration. In the field, pedon description and textural analysis of sedimentation-controlled layering are done. Of particular note is the thick cake deposited from a flash flood water pulse, which has very low permeability and can greatly inhibit infiltration. The infiltration rates measured by tension infiltrometers fluctuate, which is attributed to the mosaic and layered special distribution of hydraulic and capillary properties of the accrued sediments. Falling ponding depth laboratory experiments were conducted in four columns with a coarse substratum (sand) subjacent to a layer of thoroughly homogenized repacked dam silt. Imbibition front stopped at the interface between two texturally contrasting strata and the “waiting time” of the capillary barrier breakthrough was measured, as well as further oscillations of the infiltrations rate.

The agriculture sector in Oman, like in many other countries in the Gulf region, is based on irrigation. While blessed with rich groundwater resources in many parts of the country, Oman’s agriculture is plagued with salinity, and most recently sea water intrusion due to excessive pumping in coastal regions, where the main agricultural land is located. In order to address this issue, monitoring and limiting groundwater use for agriculture has been proposed. While a significant amount of extension effort is under way with limited or no success, this paper is an attempt to study how groundwater irrigation could be made more efficient by applying modern technology, especially, sensor-based precision irrigation in Omani agricultural farms. Even though some farms in the Al Batinah region, the largest agricultural area in Oman, have modern irrigation systems installed, hardly any are automated. As such, the operation of various types of irrigation systems are done manually with little or no attention given to water saving. Since the traditional practice of farmers in the country is furrow (flooded) irrigation, the general tendency of them is to apply more water than required to create flooded irrigation conditions. Wherever irrigation controllers are used, the control mechanism has been based on the evapotranspiration (ET) method, which requires the whole water requirement per day to be applied at once and it is inevitable that the soil gets oversaturated causing higher levels of percolation and evaporation loss. In order to prevent this, a soil moisture-based approach is proposed. This paper presents two models developed based on standard relationships for estimating irrigation requirement using both these methods and a comparative analysis showing the application areas where the soil moisture-based method may provide more water saving. It could be seen that the soil moisture-based method saves water at certain soil moisture levels under different field capacities, especially when the ET-based method may incorrectly suggest unnecessarily high water application amounts due to other environmental conditions.

2 EcOman Centre, Petroleum Development Oman LLC, PO Box 81, Muscat, Sultanate of Oman Abstract: Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture (control) or artificially structured (smart design, SD) soil substrates. Rhodes grass and ivy (Ipomea, Convolvulaceae) were grown in the pots during the hottest season in Oman. Soil moisture content (SMC) was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass (SMC of around 25%-30% compared to

The filtration of fine solid particles suspended in water by two porous media, a column of glass beads (2-mm diameter) and a column of artificial sand (1–1.6-mm diameter), was studied. A suspension of fine particles (equal and lower than silt size—called silt in this paper) in water (concentration, δ, of 25 mg/L) flows vertically through the columns. The hydraulic head and time—distance—varying δ in seeping water were measured along the depth of the column for a period of about 80 h. In the column of glass beads, most of the silt gets retained in the upper part of the column. The silt-retention front migrated downward continuously during the 80 h that the experiment lasted. In artificial sand, during the first 30 h, the top few centimeters of the filter contribute the most to the total retention of suspension. At a later stage, however, it is a deeper section of the column that contributes the most. This downward shift continues until the top layers of the column start to fully clog and the silt front stops moving down. The hydraulic conductivity, K, shows a sharp change at the interface below and above the silt retention front. It drops by 30–50 % due to the clogging for glass beads and artificial sand, respectively. The findings of this study are of paramount importance for properly managing and administrating the recharge dams especially in arid climate.

Mosaic 3-D cascade of parallelepiped-shaped silt blocks, which sandwich sand- lled cracks, has been discovered in the eld and tested in lab experiments. Controlled wetting-drying of these blocks, collected from a dam reservoir, mimics field ponding-desiccation conditions of the topsoil layer subject to caustic solar radiation, high temperature and wind, typical in the Batinah region of Oman. In 1-D analytical modelling of a transient Richards’ equation for vertical evaporation, the method of small perturbations is applied, assuming that the relative permeability is Avery-anov’s 3.5-power function of the moisture content and capillary pressure is a given (measured) function. A linearized advective dispersion equation is solved with respect to the second term in the series expansion of the moisture content as a function of spatial coordinates and time. For a single block of a nite thickness we solve a boundary value problem with a no- ow condition at the bottom and a constant moisture content at the surface. Preliminary comparisons with theta-, TDR- probes measuring the moisture content and temperature at several in-block points are made. Results corroborate that a 3-D heterogeneity of soil physical properties, in particular, horizontal and vertical capillary barriers emerging on the interfaces between silt and sand generate eco-niches with stored soil water compartments favourable for lush vegetation in desert conditions. Desiccation significantly increases the temperature in the blocks and re-wetting of the blocks reduces the daily average and peak temperatures, the latter by almost 15°C. This is important for planning irrigation in smartly designed soil substrates and sustainability of wild plants in the region where the top soil peak temperature in the study area exceeds 70°C in Summer but smartly structured soils maintain lash vegetation. Thee layer of dry top-blocks acts as a thermal insulator for the subjacent layers of wet blocks that may host the root zone of woody species.

Recently there has been an excessive groundwater pumping and seawater intrusion in the costal aquifers of Oman. To deal with this problem, a fully automated and wireless irrigation control system that avoids subjective decisions about irrigation volumes and timing was developed. All fields in the farm are accessible via TCP/IP protocol. Each farm has a Single Collecting Node for data collection connected to a host computer. All nodes in a crop are connected to Xbee network and considered as Slave Nodes except one termed Master Node. The Master Node includes two sensors and a solenoid valve. The Master Node controls the irrigation of the field with a same crop sequentially using slave nodes. Both the Xbee network and the solenoid valves are powered by a lithium battery with photovoltaic charging panels. The irrigation control and monitoring program is implemented in the host computer in the farm, which monitors the states of all crops and controls the valves using a threshold and timers. The smart irrigation system has been installed in 14 farms.

A new naturally morphed soil structure has been discovered at 2 out of 33 pedons excavated in Oman, inside and in the vicinity of a flood-protection/recharge dam, subject to a rapid geomorphological changes, caused by sediment loads from a wadi-transported runoff. Low permeable cascades of soil blocks are interspersed by highly permeable fractures filled by a natural “proppant” (sand). Different time scales (ponding with infiltration/seepage—evaporation/transpiration), the pore pressure contrast between fractures and block, capillarity (mostly of blocks), gravity (similar to oil-gas gravity drainage in reservoir engineering of fractured rock), climatological factors and transpiration of the plant roots—all control the topology of water motion in this porous double-continuum medium. Infiltration in layered soils is modeled by the Green–Ampt model with front propagating across an interface between layers of contrasting conductivity, porosity and capillarity. The goal of this work is to explain qualitatively and using a mathematical model the macroscale observations (infiltration) by a pore-scale model.