Nonlinear Optical Spectroscopy of Solid/Solid Interfaces

Three-wave mixing (3WM) spectroscopy is an exciting and relatively unexplored probe of buried solid interfaces. It possesses long penetration depths characteristic of most optical methods and intrinsic interface specificity characteristic of second-order optical processes. In this thesis we present frequency domain measurements of the ZnSe/GaAs(OOl) heterojunction by second-harmonic (SH) and sum-frequency (SF) generation. Our experiments reveal an unusual three-wave mixing resonance that arises as a result of virtual transitions between an interfacial quantum well state and the ZnSe valence band. The interfacial quantum well was brought about by interdiffusion of Zn (Ga) into GaAs (ZnSe) during sample growth. The observation introduces a new class of nonlinear optical phenomena at interfaces that can provide useful information about band profiles, diffusion and defects along the boundary of two semiconductors. We have found that this interfacial SH resonance is sensitive to a variety of structural phenomena. In essence any process that modifies the band profile near the junction will affect the strength of the resonance. We have observed the variation of interface SH spectra with respect to lattice strain relaxation and to surface reconstruction of the buried GaAs. In addition, using a newly developed photomodulationSHG (PSHG) technique, we have exploited this sensitivity to determine the nature and relative density of interface charge traps as a function of substrate surface reconstruction. The PSHG method was also used to study free charge trapping mechanisms at ZnSe/GaAs(OOl) heterointerfaces. Our measurements determined that the interfacial trap-centers are mainly hole-traps with lifetime of 35 sec. In the course of carrying out these experiments we also observed interference in reflected second harmonic generation from two adjoined nonlinear slabs. A theory for the phenomena was presented and was used to understand our experimental results with ZnSe/GaAs(OOl) heterostructures. This interference phenomena was introduced as a new methodology to measure the second-order susceptibility of thin overlayer materials

Chemical and microbiological changes of salted Caspian kutum (Rutilus frisii kutum) roe

Salted kutum roe was prepared by soaking in brine to a traditional procedure. Proximate composition (moisture, protein, lipid, pH, ash and salt content), total volatile basic nitrogen (TVB-N), fatty acid profiles and microbiological characteristics of raw and salted roe of Caspian white fish (Rutilus frisii kutum) were determined. The results indicated that protein and moisture contents were significantly higher in raw roe compared to salted one (28.81 and 61.07% to 23.99 and 51.57%, respectively). Significant differences in ash and salt contents were obtained among different treatments. TVB-N in all samples was less than 25mg/100g. The gas chromatography (GC) analysis showed that the major saturated fatty, monounsaturated fatty acids and poly unsaturated fatty acids were 16:0, 18:1n-9, and 22:6n-3, respectively. Aerobic plate count (APC) and Total Coliform Count (TC) in all samples were significantly higher (p<0.05) in raw roe (5.33 logCFU/g and 210 MPN/g) compared to salted roe (1.23 log CFU/g and 1.2 MPN/g). None of the samples contained Escherichia coli, Salmonella, Clostridium perfringens or yeast

Effects of Shear Wave Velocity Profile of Soil on Seismic Response of High Rise Buildings

There is, nowadays, a conspicuous demand for the high rise buildings in the high-density dwellings of the urban areas; in consequence, harnessing the whiz-bang numerical simulations plus conducting the rigorous experimental studies so as to design and construct such prodigious structures would be essential. Thus, the appropriate parameters for modeling the structure and the soil medium in the Soil-Structure Interaction (SSI) system should be selected. The soil-structure interaction is referred to the process in which the soil response is told on by the structure motion whilst the latter is affected by the soil motion. The current research zeroed in on the soil shear wave velocity and its influence on the superstructure performance. Invoking the weighted average shear wave velocity with the aim of calculating the soil shear modulus, which is closely related to the strength and deformation characteristics of the soil, has been a hotly debated issue since the aforesaid parameter was posited by a plethora of codes and regulations to obtain the soil site classification required for the earthquake design. To that end, the numerical model, having two assorted profiles associated with the shear wave velocity, namely, the in situ non-uniform profile (Case A) and the equivalent uniform profile (Case B), was built by means of FLAC3D, capable of analyzing the complex interaction issues via the direct method whereby the entire system of the structure-foundation-soil is modeled and analyzed in one single step. To put it in a nutshell, employing the weighted average shear wave velocity for the entire soil mass in parsing of the 3D seismic soil-structure interaction problems would be accused for ending up with somewhat unreliable results, e.g., underestimated drift ratio and building deformation, which might be the culprit of the damage to the building and possibly the death of the residents residing in the earthquake-prone zones

Effects of fennel (Foeniculum vulgare) essential oil of diet on some biochemical parameters and salinity stress resistance of kutum (Rutilus kutum) fry

This study was carried out to investigate the effects of different levels of fennel essential oil (Foeniculum vulgare) on some biochemical parameters and salinity stress resistance of Caspian Kutum (Rutilus kutum) fry. For this purpose, Kutum fry with an average initial weight 0.6±0.002 gr were divided randomly in 5 treatments including 0 (control), 100, 200,400 and 600 mg fennel essential oil/kg diet and fed 3 times a day at a ratio of 7-12% body weight for 60 days. At the end of the experiment, biochemical parameters and salinity stress resistance were assessed. Results of serum biochemical analyze showed that the highest level of total protein and globulin was observed in 600 mg fennel essential oil/kg diet. The highest level of albumin and cholesterol was observed in 100 and 400 mg fennel essential oil/kg diet and the highest level of triglyceride, glucose and cortisol was observed in control (p<0.05). Results of salinity stress (6, 13 and 20 g/l) showed that 100 and 400 mg fennel essential oil/kg diet treatments showed the lowest response to stress and there were the lowest changes in cortisol and glucose levels before and after stress compare to control. Highest survival was observed in 100 and 400 mg fennel essential oil/kg diet. In conclusion results suggested that Fennel essential oil can improve immune system of fries by promoting biochemical parameters (total protein, albumin, globulin, triglyceride, glucose and cortisol). Also plays important role in increasing stress resistance of Kutum fry and the best operation is related to 100 mg fennel essential oil/kg diet

Comparison of Analgesic Effect Between Gabapentin and Diclofenac on Post-Operative Pain in Patients Undergoing Tonsillectomy

Background: Tonsillectomy is a common procedure causing considerable postoperative pain. Postoperative pain intensity of 60 - 70 in the scale of visual analog scale (VAS) has been reported up to 3 - 4 days which could continue until 11 days after the surgery. Objectives: The current study aimed to compare the analgesic effect of gabapentin and diclofenac on pain after tonsillectomy with the control group. Patients and Methods: In this double-blind, placebo-controlled clinical trial, 90 patients aged 10-25 years, ASA classes I and II were randomly selected to receive 20 mg/kg oral gabapentin (n = 30), 1.0 mg / kg rectal diclofenac (n = 30) or placebo (n = 30) preoperatively. Pain was evaluated postoperatively on a visual analogue scale at 2, 6, 12 and 24 h. Opioid consumption in the first 24 h after surgery and the side effects were also recorded. Results: There was no significant difference in terms of age, sex, and time of surgery in the three groups. Patients in the gabapentin and diclofenac groups had significantly lower pain scores at all-time intervals than those in the placebo group. The total meperidine consumed in the gabapentin (14.16 ± 6.97 P = 0.001) and diclofenac (16.66 ± 8.95, P = 0.004) groups was significantly less than that of the placebo (33.4 ± 13.97) group. The frequency of side effects such as vomiting, dizziness, and headache was not significantly different among the groups. Conclusions: It can be concluded that gabapentin and diclofenac reduced postoperative pain and opioid consumption without obvious side effects

Microbial and biochemical characteristics of fermented fish sausage from common carp (Cyprinus carpio) mince by application of Pediococcus pentasaceus at different incubation temperatures

Fermented sausage is a favorite kind of meat-product that has allocated great proportions of meat consumption in the world. For the first time in Iran in this study the production of Fermented sausage from minced meat of common carp was assessed by means of lactic acid bacteria at different incubating temperatures as 15, 25, and 35˚C. To prepare the fish sausage, common carp mince was grounded and mixed with NaCl (3%), glucose (3%) and lactic acid bacteria at 5 log CFU/g and afterward were incubated for 48 h. During the incubation of fish sausage, microbiological tests, moisture and protein content, and TVB-N were measured. According to the results, the higher temperature of 35˚C stimulated the rapid growth of lactic acid bacteria, resulting in a rapid decline in pH, and consequently suppressed the growth of pseudomonas, Micrococcaceae and Enterobacteriacea

An investigation on Vibrionaceae family of bacteria as probiotic factors in shrimp culture

We investigated the effects of Vibrionaceae family of bacteria as probiotics in the process of growth and survival rate of shrimp during propagation stages. Bacterial flora were extracted from seawater, culture farms, shrimp culture farms and sludge of private propagation farms. Different bacteria such as Vibrio alginolyticus (serotype 1-4), Vibrio splendidus I, Vibrio fluvialis II, Vibrio anguillarum I, Vibrio costicul, Vibrio vulnificaus, Vibrio nereis, Vibrio camplbelli, Vibrio natriegens, Vibrio proteolyticus, Vibrio plegius II ,Vibrio fischeri, Aeromonas hydrophila, Aeromonas schuberti, Aeromonas salmonisida, Aeromonas veronii were isolated, identified and lyophilized. These bacteria were used in different experiments on shrimp life cycle stages while the shrimps were being fed on live food such as Chaetoceros, Skeletonema and Tetraselmis algae. Vibrio alginolyticus (serotype 1) with 107 cells/ml increased proliferation of Tetraselmis sp to 71 % in 6 days compared to the control experiment. Also Vibrio alginolyticus (serotype 4) with 105 cells/in' increased Tetraselmis sp. production to 389% in 6 days compared to control. Vibrio splendidus I was also found to be able to increase shrimp fork length in postlarvae stage 3 up to 23% as compared to control. Vibrio alginolyticus and Vibrio fischeri increased survival, fork lenght and body weight of green tiger shrimp in postlarvae stage significantly (P<0.05)

Experimental investigation on the use of waste elastomeric polymers for bitumen modification

The study described in this paper focused on the possible use of waste products coming from the production of styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR), as bitumen modifiers. Modified binders containing these products were prepared in the laboratory with different polymer dosages and were thereafter subjected to the evaluation of empirical and rheological properties. For comparative purposes, the study also considered SBR and PBR products of premium quality. Ageing effects were also taken into account by means of proper laboratory simulations. Obtained results indicated that the two types of polymer (SBR and PBR) have completely different effects on the rheology and expected performance of the resulting modified binders. In particular, while the two polymers showed similar effects in terms of resistance to permanent deformation, the SBR products proved to be superior from the viewpoint of fatigue resistance. However, only minor differences were found when comparing the effects produced by premium quality and waste polymers. As a result of the experimental findings, it was concluded that the use of waste SBR polymers can be an attractive solution for the production of affordable modified binders

Effects of starvation and refeeding on the hematological and serum parameters and body proximate composition of Caspian salmon (Salmo trutta caspius) fingerligs

This study was conducted to investigate the effects of periods of starvation and refeeding on some hematological, serum parameters and whole body proximate composition in Caspian salmon (Salmo trutta caspius). 240 samples of the Caspian salmon with an average weight of 13.73 ± 0.63 g were kept in 300 liter polyethylene tanks. Samples were fed twice a day with Rainbow trout commercial feed to the point of satiation. This experiment lasted for 10 weeks with control (without starvation) and 3 starvation treatments including 2, 4 and 6 weeks of starvation followed by 4 weeks of refeeding with 3 replicates. During rearing period, the average of water temperature, pH and dissolved oxygen were 14.15±0.27 ° C, 8.44±0.17 and 6.34±0.24 mgl-1, respectively. At the end of starvation period, the results of blood parameters showed that starvation significantly increased red blood cells and hematocrit in treatment with 2 weeks of starvation (0.893±0.58 × 106/mm3) and 6 weeks of starvation (42.33±3.21 %, P0.05). At the end of the experiment, the lowest value of lipid belonged to starvation treatments while the highest value was observed in control (P<0.05). Generally, this can be inferred that Caspian salmon fish can tolerate starvation for 2 weeks without any negative impact on blood and serum biochemical parameters and for 4 weeks on whole body proximate composition