Abstract

Accurate human gender identification relies on a specific locus (gene) on DNA known as Amelogenin, which has crucial applications in many scientific disciplines, such as prenatal diagnosis of genetic disorders related to this gene. Molecular genetics techniques are specifically used to detect length variations in the X and Y homologues of this gene for gender determination. This sex test is an integral part of PCR multiplex kits used for DNA profiling. However, a number of results have shown an anomaly (ambiguity) where the male Y chromosome is absent in some males, resulting in a genotype showing only the female X chromosome, even though males typically have both X and Y chromosomes at this locus. This study aims to determine the frequency of this anomaly, called AMELY null (Y chromosome dropout), in the Libyan population. This study revealed the presence of a mutation at the Amelogenin sex-determining locus at a frequency of 0.1175% in the Libyan population, manifested as the loss of the Y chromosome in males. These results show that gender determination using this technique should be interpreted cautiously, especially in forensic cases where the sample obtained from the crime scene is of unknown gender.

Abstract

An airborne geophysical survey measuring gamma-ray spectra and the earth's magnetic field was conducted in the Wadi Shatti area in south-central Libya at the end of the last century. The area was previously known to contain sedimentary lenses of iron ore. The primary objective of the geophysical survey was to explore the mineral potential of the area. Some of the radioactive anomalies recorded by the gamma-ray spectrometer were analyzed to determine the equivalent uranium (eU), equivalent thorium (eTh), and equivalent potassium (eK) of these anomalies. Surprisingly, some of these anomalies were located at sabkhas and swamps fed by artesian springs resulting from groundwater flow. A high level of radioactivity was found at one artesian spring, with scintillometer measurements showing an activity of 1500 counts per second. This radioactivity could be attributed to the geological formations carrying the groundwater, disequilibrium in the decay of various radioactive series, subsurface phosphate layers, phosphate fertilizers, or other reasons. Regardless of the cause of this notable radioactivity, some of the natural springs in the area are used for drinking water and irrigation. Although some of these anomalies are located in remote desert areas, they should be considered environmental geophysical anomalies and studied in detail with follow-up, including monitoring the health records of the population in the areas where these anomalies are located.

Abstract

Feeding experiments were conducted to test the use of the compensatory growth phenomenon to improve growth efficiency and feed utilization for gilthead seabream (S. aurata). Five feeding cycles were applied in the experiment: daily feeding; one week of starvation followed by one week of feeding (1:1); two weeks of starvation followed by two weeks of feeding (2:2); three weeks of starvation followed by three weeks of feeding (3:3); and six weeks of starvation followed by six weeks of feeding (6:6). At the end of the experiment, it was found that fish treated with the 3-week feeding cycle (3:3) showed results comparable in terms of growth performance to fish treated with the daily feeding regime. The results also showed efficiency in feed utilization in terms of food conversion ratio (FCR) and feeding efficiency (FE%) compared to other feeding cycles. The results of the 1, 2, and 6-week cycles were not as good as the 3:3 cycle and the daily feeding regime. The study provided evidence of the occurrence of compensatory growth in fish when applying a feeding cycle of three weeks of starvation followed by three weeks of feeding.

Abstract

The effects of salinity (NaCl) on potato (*Solanum tuberosum* L.) variety Spunta were evaluated using plant tissue culture at 5 levels of NaCl (0, 20, 40, 60, 80, 100 mM) using single-node explants. Significant effects were observed among the plantlets cultivated at different NaCl levels. Salinity stress gradually inhibited the growth and development of plantlets with increasing NaCl concentration in the used growth medium (MS). The growth traits tested for plantlets grown in MS medium containing 20 mM NaCl showed no differences compared to the control, except for plantlet length, which decreased significantly by 36% compared to the control. Increasing salinity beyond 20 mM showed a progressive decrease in all studied growth traits. All plantlets survived in the growth medium containing a high level of NaCl (100 mM) but showed a severe reduction in growth rate. Based on the obtained results, the salinity tolerance of the Spunta variety can be estimated as moderate.

Abstract

This study focuses on the behavior of super duplex stainless steel (EN 1.4410, UNS S32750) subjected to laser beam welding and activated Tungsten Inert Gas (TIG) welding using silica powder flux. The study aimed to evaluate the effect of these welding techniques on the microstructure and hardness of weld joints of 3mm thick plates. The results revealed that both techniques play an important role in obtaining satisfactory mechanical properties. Using nitrogen as a shielding gas with argon in laser welding resulted in an improved microstructure of the weld metal compared to TIG welding, leading to a change in the standard ratios of ferrite and austenite phases in the weld metal and heat-affected zone (HAZ). In laser welding, the very high cooling rates resulted in an improper ferrite/austenite balance due to decreased austenite content and subsequently increased ferrite content compared to the base metal. Hardness measurements showed an increase in the hardness of the HAZ for both processes, with slightly higher hardness in the case of laser welding.