مجله علوم و فنون دریایی
سال بیستم شماره 3 (پاییز 1400)

Mineralized collagen has diverse biological advantages, biocompatibility and biodegradability. In this study, the process of mineralization of the protein collagen type I extracted from the scales of white fish (Rutilus Frisii Kutum), was investigated in the Simulated Body Fluid (SBF). During immersion in SBF, tricalcium phosphate crystals were precipitated into collagen nanofibrils. SDS-PAGE electrophoresis confirmed the presence of type I collagen, including 3 spiral strands. Infrared Fourier Transform (FTIR) spectroscopy technique was used to characterize extracted collagen nanofibrils and mineralazied collagen. The presence of 60% of minerals in the mineralized Acid Soluble Collagen (ASC) was confirmed by TGA. DSC was used to determine the denaturation temperature of mineralized ASC at 147.5 °C, indicating a higher thermal stability of mineralized collagen. TEM images showed irregular and dense formation of tricalcium phosphate nanoparticles on collagen nanofibrils. Mineralized collagen protein can provide new insight into producing porous scaffolds for tissue engineering, dental implants, and providing medical equipment.

Arvandrud River Plume which is the main source of fresh water in the Persian Gulf and in addition its catchment area is settlement for about 54 million people is one of the most important phenomena in costal zones. . The river is the boundary line between Iran and Iraq and its plume extended in Iran, Iraq and Kuwait territory in Persian Gulf. Oceanographic studies are infeasible in the river and in its mouth due to geographic, politics, and security problems in the region. Despite the lack of in-situ data, this study is a serious step to the investigation to river plume. In this study salinity, temperature and water circulation of Persian Gulf were simulated by using oceanographic hydrodynamic model, FVCOM. Then, effects of wind and river discharge on structure of Plumes were investigated. For this purpose, 14 wind and 8 river discharge conditions have been used. The results show the river has a surface-advected plume that is highly affected by wind. The river plume area decreased with increasing wind speed. Three types of plumes were formed by different wind conditions, at the mouth of the river. Plume type 1 diverted toward the northwest coast of Persian Gulf and plume type 3 diverted toward the Kuwait coast. Plume type 2 was almost straight and was not diverted to the sides. The T-S diagram of surface water mass was very similar to all three modes, as a result, the plume shape and displacement is affected by wind.

The new insights into ocean-atmosphere-land synoptic studies, have led scientists to trace attractive atmospheric and oceanic phenomena. In this study, by using synoptic maps and some precipitation indices for Iran, we estimated the type and intensity of the extreme precipitation event in Dayyer Port synoptical station (27˚51ʹ34ʺN-51˚57ʹ52ʺ, ID: 40872) for 19March 2017. In order to identify oceanic sources of the water content for this precipitation event, air parcels were traced as lagrangian single particle trajectory by a hybrid model of HYSPLIT which is run backward interactively on the web site, during 9-days by the start of maximum rainfall, locatacted at Dayyer port station. Accordingly, we plotted pattern of the average moisture transfer paths on 800-550 hPa atmospheric levels. The field climate data (including wind speed and direction, relative humidity and precipitation) with 6-hour time steps and spatial resolution of 2.5˚×2.5˚(longitude and latitude), entered into the model from the reanalysis global data archive of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). Consequently, by assessment of the meteorological maps and data and by using a precipitation index of R10mm, we found that this precipitation event (19th March 2017) defined as a heavy precipitation day. Finally, the simulation outputs clearly showed that the water contents of this rainfall system (19th March 2017) originates from two source locations of the north area of Indian Ocean (Arabian Sea), and also the east part of Atlantic Ocean. In addition, the results illustrated that during the occurrence of this precipitation event, an extra-tropical cyclone was active on the studied area.

ArvandRoud is known as the most important fresh water inlet of the Persian Gulf and plays a key role in controlling salinity, especially in its northern portion. Since the northern part of the Persian Gulf is exchanged with lagoons and wetlands due to tide, its salinity is of great importance to the ecosystem of the region and the coasts of Khouzestan. In this study, using the Mike model based on the three-dimensional solution of the Navier Stokes equations, assumption of incompressibility, Boussinesq aproximation, and hydrostatic pressure, the effect of Arvandroud on Persian Gulf salinity in two states has been investigated investigated: with a discharge rate of 1400 m3/s and without Arvandroud. The results show that by ignoring the entrance of the Arvandroud to the Persian Gulf, the peak of salinity at the Gulf increases to 7 PSU and affects the southern half of the Persian Gulf along the Arabian coasts. Also, results implicitly indicate that Arvandroud discharge rate has no effect on the amount of water entering and leaving the Strait of Hormuz.

The aim of this study was to investigate the effect of solid-state fermentation on quality properties, enzyme activity and apparent digestibility of nutrients of Kilka Anchovy. Kilka Anchovy meal were mixed with 25% wheat flour and inoculated with microorganisms (108 cell/ml) and kept in an incubator for 14 days at 37 ºC. Comparison of oxidation and hydrolysis indexes at Kilka Anchovy silage inoculated with microorganisms showed that S. cerevisiae was the lower free fatty acid (7.62 µ mole/g fish) and peroxide (12.47 meq peroxide/1000g oil). The lowest nitrogen non protein of Anchovy Kilka silagr was shown with fish silage inoculated with L. plantarum and B. subtilis. The lowest thiobarbituric acid (8.40 mg malonaldehyde/ kg) was showed at fish silage inoculated with fungi A. niger. The highest α-amylase and acidic protease activites was shown at fish silage inoculated with fungi A. niger and yeasts (S. cerevisiae and S. carlesbergensis), respectively. The in vitro digestibility of dry matter and crude protein with different levels of the fish silage increased. The highest of in vitro digestibility of dry matter and crude protein was related to S. cerevisiae (P>0.05). Generally, the results showed that S. cerevisiae had the best quality properties, enzyme activity and digestibility of nutrient of fermented silage compared with other fish silage inoculated with other micoorganisms.

Bisphenol-A (BPA) is one of the most important endocrine disrupters that has arrived to the environment, because of this reason, it has been developed into a detrimental material for human beings and other organisams. There are several ways for degradation or removal  of  industrial pollutants, in which the bacterial communities plays a major role in the biodegradation of BPA in the environment.In this study, contaminated sediments were collected in Mousa Creek. The isolates were identified by biochemical tests and 16S rRNA gene sequence analysis. The isolated Bacteri was Pseudomonas putida. Growth and degradation ability of isolated baccteri was measured in 100, 200 and 300 ppm of BPA in 24-hour intervals for 6 days. Bacterial growth rate was detected with spectrophotometer at 600 nm. Efficiency of BPA degradation was performed by Liquid-liquid extraction method and measured by HPLC. This bacteri was able to grow at concentrations of 100, 200 and 300 ppm of BPA. So, the biodegradation results from mineral salt medium (MSM) indicated that Pseudomonas putida have the best degradation efficiency at the 200 ppm of the BPA. Biodegredation result by HPLC method show that the percentage of the degradation efficiency at the 200 ppm was 82.8 percent.These results demonstrated this indigenous bacteria (Pseudomonas putida) can be used to improve the bacterial communities contaminated by Bisphenol A and to eliminate the pollutants from the costal environment.

In this study, the structure of fish populations of Saurida tumbil in the waters of Hormozgan province was studied using morphometric and meristic characteristics. Samples were obtained from three parts of Bandar Lengeh, Hormoz Island and Minab and 22 morphometric characteristics and 5 meristic characteristics were measured in each fish .Morphometric characteristics were standardized before the analysis to reduce the errors caused by alometric growth. The results of one-way ANOVA showed that 9 morphometric characteristics were significantly different among the samples in different regions, also, there were no significant statistical differences between the specimens in the 5 meristic characteristics. The results obtained from the distinguishing functions 1 and 2 for the morphometric characteristics showed a high degree of differentiation among Saurida tumbil stocks in the three studied regions. While there was little difference about the meristic characteristics and the samples areas were highly overlapping in the three study. On the other hand, the percentages of people who were correctly placed in their main population were for morphometric and meristic characteristics, 94.3% and 49.5% respectively. The results of this study showed that S.tumbil differ in terms of morphometric features and it is likely that there exist different stocks of this species in Iranian coasts of the Persian Gulf in Hormozgan that should be considered for fisheries management.

In order to study in shallow coastal areas, free Landsat 8 image with relatively high radiometric resolution and the presence of two bands, coastal blue and blue is suitable. In this study, in addition to Landsat satellite imagery, hydrographic data has also been used. In order to increase the accuracy and reduce the error, tried as much as possible the passing time of the Landsat 8 sensor close to the acquisition terrain date. The purpose of this study is bathymetry of the southeastern part of the Caspian Sea using the PCA algorithm on the pre-processed visible region. In this study, the FLAASH and Dark Object Subtract (DOS) atmospheric corrections were applied separately to visible bands. The obtained depth results by applying PCA transformation to these two types atmospheric correction is investigated. PCA algorithm is implemented in four different forms. Statistical parameters R^2, RMSE, and NRMSE are calculated between obtained data by PCA and hydrographic data in two types of atmospheric correction. The results show that in both of atmospheric correction, the accuracy of estimated depth by PCA is increased when four or three PCA components are introduced as algorithm inputs compared with only two or one PCA components are used. As well as, the use of four components, the accuracy of DOS in bathymetry with values of R2=0.91, RMSE=0.3,and NRMSE=0.05 has shown a better result in comparison to FLAASH correction's values R2=0.87, RMSE=0.38, and NRMSE=0.06.

Islamic Republic of Iran and Saudi Arabia are two important and decisive countries in the Middle East and the Persian Gulf, and various reasons have led to continued tensions in relations between the two countries. At present, for various reasons, the relations between the two countries are moving towards divergence, and a vague future for the relations between the two countries is conceivable.The subject of the present study is the analysis of tensions and competition between Iran and Saudi Arabia in the Persian Gulf region. In other words, the aim of the present study is to investigate the main cause of tension in the relations between the Islamic Republic of Iran and Saudi Arabia in the Persian Gulf and evaluate it based on the structure of international relations. The research method of this research has been done in terms of descriptive-survey and exploratory data analysis. The research findings show that due to the regional development in the Persian Gulf including the crisis in Syria, Iraq, Yemen, and the nuclear deal between Iran and European countries, Iran’s power and influence has been increased and this condition has been considered as a threat by Saudi resulting in an increasing tension and conflicts between the two countries which might develop and continue. Differences in relations between the two countries, which could increase competition. Given the above and Iran's influential power in the region, Saudi Arabia has provided the necessary ground for USA and Israeil influence in the region and has established close ties with Israel. Therefore, the approach of clear political relations in the future of the two countries is vague and tense.

One of the important goals of designing of planing boats is to achieve higher speeds, one of the major obstacles to this issue is longitudinal instability.In this research, a new method is proposed to solve the longitudinal instability of steped planing boats. In this method, using the transverse curvature or variable deadrise angle of the body, the instability of boat has been corrected. Two bodies, called Nimala1 and Nimala2, were tested in National Iranian Marine Laboratory. The main difference between the two transverse curvature bodies is that Nimala1 has a constant deadrise angle and nimala2 has a variable deadrise angle in a section. To determine the effect of the variable deadrise angle on the longitudinal instability, each of the models has been tested up to longitudinal instability. Due to the equipment installed during the test of the model in the towing tank, it was not possible to measure the movement and therefore numerical analysis is used as a complement to the exprimental test. The results show that the variation in cross-curvature has a significant effect on longitudinal instability. By shifting the center of pressure to Aft, the delay of the porpoising was changed from 5.89 volumetric Fn in the fixed deadrise angle model, to 8.34 volumetric Fn in Variable deadrise angle model. Also, the resistance of this body is not significantly different from that of a body with constant transverse curvature, especially at high speeds.