Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase

A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images.

Association of SRD5A2 gene mutations with risk of hypospadias in the Iranian population

BACKGROUND

Hypospadias is one of the most common forms of congenital malformation of the male external genitalia worldwide. The ratio in the Iranian population is one in 250 live male births. The conversion of testosterone to dihydrotestosterone (DHT) in the presence of steroid 5α-reductase 2, which is encoded by SRD5A2 gene, plays an important role in the normal development of the male reproductive system.

METHODS

We examined whether SRD5A2 gene mutations (V89L and A49T polymorphisms) are associated with the risk of hypospadias in the Iranian population. We performed exons sequencing for SRD5A2 gene in 109 hypospadias patients.

RESULTS

We identified two new mutations in the subgroups of affected cases: including a substitution of the nucleotide T > A in the codon 73 [c.219T > A (p.Leu73_Ser74insHisPro)] and an insertion of an extra A nucleotide in the codon 77 [c.229insA* (p.Gly77*)]. Additionally, we performed PCR-RFLP for the two identified polymorphisms and revealed that V89L [OR = 5.8, 95% CI (3.8-8.8), p value < 0.001] and A49T [OR = 10.16, 95% CI (3.94-26.25), p value < 0.001] are significantly associated with hypospadias occurrence in patients. Our haplotype analysis further indicated that the Leu-Ala haplotype increases risk of hypospadias; conversely, the Val-Ala haplotype decreases the risk of hypospadias in the studied patients.

CONCLUSIONS

This study demonstrates that polymorphisms in the SRD5A2 gene could be considered as a risk factor for hypospadias disease emergence.

Optimization of microfluidic gallotannic acid extraction using artificial neural network and genetic algorithm

The current study presents the outcomes of modeling and optimizing extraction of gallotannic acid from Quercus leaves using a microfluidic system. In this study, the effects of various experimental parameters were investigated using the method of design expert. Number of experiments suggested is 31 by central composite design of Design Expert. The experimental results of design expert were analyzed by artificial neural network (ANN). Based on the results of ANN, independent variables experiment: temperature (T), flow rate ratio (FR) and pH have shown a negative effect on extraction yield (dependent variable), while the residence time (RT) has shown a positive effect. In trained network, ${R^2} = 0.9805$ and RMSE = 0.0166 shows good agreement between the predicted values of ANN and experimental results. Optimum extraction conditions, to reach maximum yield by genetic algorithms (GA), were FR = 0.53, RT = 26.4, pH = 2.06 and T = 21.44 ${R^2} = 0.9805$ . The extraction yield under the optimum predicated conditions was 96.4 %, which was well matched with the experimental value 95.01 % $\pm 0.63$ . Based on the obtained results, it was found that the ANN model could be employed successfully in estimating the gallotannic acid extraction efficiency using microfluidic extraction method.

CFD study of the flow pattern in an ultrasonic horn reactor: Introducing a realistic vibrating boundary condition

Recently, great attention has been paid to predict the acoustic streaming field distribution inside the sonoreactors, induced by high-power ultrasonic wave generator. The focus of this paper is to model an ultrasonic vibrating horn and study the induced flow pattern with a newly developed moving boundary condition. The numerical simulation utilizes the modified cavitation model along with the "mixture" model for turbulent flow (RNG, k-ε), and a moving boundary condition with an oscillating parabolic-logarithmic profile, applied to the horn tip. This moving-boundary provides the situation in which the center of the horn tip vibrates stronger than that of the peripheral regions. The velocity field obtained by computational fluid dynamic was in a reasonably good agreement with the PIV results. The moving boundary model is more accurate since it better approximates the movement of the horn tip in the ultrasonic assisted process. From an optimizing point of view, the model with the new moving boundary is more suitable than the conventional models for design purposes because the displacement magnitude of the horn tip is the only fitting parameter. After developing and validating the numerical model, the model was utilized to predict various quantities such as cavitation zone, pressure field and stream function that are not experimentally feasible to measure.

Preparation of a reproducible long-acting formulation of risperidone-loaded PLGA microspheres using microfluidic method

The aim of the present study is to prepare risperidone-loaded poly lactic-co-glycolic acid (PLGA) microspheres within microfluidic system and to achieve a formulation with uniform size and monotonic and reproducible release profile. In comparison to batch method, T-junction and serpentine chips were utilized and optimizing study was carried out at different processing parameters (e.g. PLGA and surfactant concentration and flow rates ratio of outer to inner phase). The computational fluid dynamic (CFD) modeling was performed, and loading and release study were carried out. CFD simulation indicates that increasing the flow rate of aqueous phase cause to decrease the droplet size, while the change in size of microspheres did not follow a specific pattern in the experimental results. The most uniform microspheres and narrowest standard deviation (66.79 μm ± 3.32) were achieved using T-junction chip, 1% polyvinylalcohol, 1% PLGA and flow rates ratio of 20. The microfluidic-assisted microspheres were more uniform with narrower size distribution. The release of risperidone from microspheres produced by the microfluidic method was more reproducible and closer to zero-order kinetic model. The release profile of formulation with 2:1 drug-to-polymer ratio was the most favorable release, in which 41.85% release could be achieved during 24 days.

Zeolite Nanoparticles for Selective Sorption of Plasma Proteins

The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.

Effect of various ratios of carbohydrate-protein supplementation on resistance exercise-induced muscle damage

AIM

Previous studies have indicated that exercise-induced muscle damage might be attenuated by coingestion of protein and carbohydrate supplement. The purpose of this study was to compare the effect of three various ratios of carbohydrate-protein (CHO+PRO) supplements on resistance exercise-induced muscle damage indices.

METHODS

Twenty-eight untrained male students voluntarily participated in this study and were randomly assigned to one of the four groups: 1) CHO+PRO 2:1 ratio, N.=7; 2) CHO+PRO 3:1 ratio, N.=8; 3) CHO+PRO 4:1 ratio, N.=7; 4) placebo group, N.=6. They performed a single bout of resistance exercise (whole body: 3 set×8-10 reps with 70-75% 1RM), with eccentric concentration. Every group consumed prepared CHO/PRO beverages (9% concentration, 10 mL/kg/bw-1 at different ratios) or the same amount of placebo beverage before and in 15 min intervals during exercise. Blood samples were taken before the exercise bout and also at 1 and 24 h post-exercise. In addition, muscle soreness scores were recorded before and 1, 24, and 48 h postexercise. Repeated measures ANOVA (between-within design) and Bonferroni post hoc test were used to analyze dependent measures (α=0.05).

RESULTS

Serum creatine kinase (CK) and myoglobin (Mb) increased in all groups compared with pre-exercise but the significant difference among groups was observed in 24 h postexercise, in a way that both CK and Mb levels were higher in placebo group. Muscle soreness increased for all groups from pre to postexercise, but there was not any significant difference among groups at any time point.

CONCLUSION

Findings of this study showed that CHO+PRO decreased serum CK and Mb at 24 h post exercise, but did not affect muscle soreness at any time points after exercise. Moreover, there were no significant differences between various ratios of CHO-PRO supplementation.

Unerupted primary molar teeth positioned inferior to the permanent premolar: a case report

Primary tooth impaction is a rare finding during the development of primary dentition. Several factors contribute to the impaction of a deciduous tooth. This report describes the diagnosis and treatment of a 10-year-old boy who presented an impacted second primary mandibular molar. This tooth, located inferior to the second premolar together with an odontoma, was positioned superior to the premolar teeth. Treatment consisted of surgical removal of the impacted deciduous tooth and odontoma and placement of a passive lower lingual holding arch. Periodic examination was indicated for follow-up. Early intervention was recommended to manage orofacial disfigurement and to avoid consequent problems.

Optimal dose of pre-incision/post-incision gabapentin for pain relief following lumbar laminectomy: a randomized study

BACKGROUND

Gabapentin has been introduced as an effective agent for post-operative pain control. This study aimed to test the effects of pre- and post-incision administration of different doses of gabapentin on post-operative morphine requirement and pain following lumbar laminectomy.

METHODS

In this randomized clinical trial, 175 patients were allocated into seven groups of 25 patients each to receive placebo or gabapentin 600, 900 or 1200 mg pre- or post-incision. Total patient-controlled intravenous morphine consumption during the first 24 post-operative hours, and the time to the first demand for morphine were recorded. Pain score at rest (visual analogue scale) was recorded every 30 min in the first 4 h and then every 2 h until 24 h post-operatively. Side-effects were observed.

RESULTS

In the first 12 h, morphine consumption was less, pain scores were lower and the time to the first demand for analgesia was longer in groups receiving gabapentin 900 or 1200 mg either pre- or post-incision, compared with placebo and gabapentin 600 mg (P<0.001). There was no difference between gabapentin 900 and 1200 mg. Pain score, morphine consumption and time to the first demand for analgesia in equal pre- or post-incision doses of gabapentin were not significantly different. No differences in the side-effects were observed between groups.

CONCLUSION

Gabapentin 900 or 1200 mg, administered either pre- or post-incision, was found to be effective in pain management following lumbar laminectomy. Similar doses of gabapentin provide the same post-operative analgesia whether administered pre- or post-incision.

A novel technique for the removal of fractured instruments in the apical third of curved root canals

AIM

To report on a conservative approach for removal of a fractured file in the severely curved apical portion of the distobuccal canal of a mandibular molar.

SUMMARY

With the assistance of stainless steel hand files and a chloroform-dipped gutta-percha cone, a fractured rotary NiTi instrument was successfully removed. The use of this technique may assist in removal of loose instrument fragments that are not easily accessible to other removal techniques.

KEY LEARNING POINTS

Instrument fractures do not always lead to an unfavourable prognosis and their removal from the apical third of curved canals should not be routinely attempted. The case highlights that it is possible to conservatively remove loosely bound objects from the hard-to-reach areas of the root canal system.

Occupational stress and work-related unintentional injuries among Iranian car manufacturing workers

This study in 2004 and 2005 aimed to present the pattern of job stress among car manufacturing workers in one factory in the Islamic Republic of Iran, and to assess its relationship with occupational injuries. Data were collected from 608 male workers (508 at-risk general workers and 100 with injuries in the last year). Job stress was assessed by the Belkic occupational stress index. The prevalence of job stress was 21.3%. The main occupational stressors were time pressure (78.5%), mode of payment and evaluation (56.4%), and interaction with people and machines (41.3%). The risk of injury among those with job stress was significantly higher than those without job stress (OR = 2.0; 95% CI: 1.20-3.30). Job stress was responsible for 11.9% of all occupational injuries in this group.

The effect of anionic and cationic surfactants on indicators and measurement of dissociation constants with two different methods

The effects of cationic cetyltrimethylammonium bromide (CTAB), hexadecylpyridinum chloride (HDPC) and anionic sodium dodecylsulphate (SDS) surfactants on dissociation constants and transition intervals of methyl red, methyl orange and cresol red were studied spectrophotometrically. The results show that all studied indicators strongly interacted with cationic micelles (CTAB and HDPC). In the case of methyl red, relatively strong interaction with anionic surfactant (SDS) was obtained. However, no effect of SDS on dissociation constants of cresol red and methyl orange was observed. The dissociation constants of indicators were calculated with both the proposed and known chemometric (DATAN) method with a reasonable agreement on the data achieved.