Omentopexy for the repair of diaphragmatic defect and adhesion assessment of viscera to propylene mesh- an experimental study in rabbits

Background  

The use of synthetic mesh for the repair of major congenital diaphragmatic hernia may cause visceral adhesion to the prosthesis and ongoing complications. In the present study, the use of propylene mesh for the repair of diaphragmatic hernia and the role of omentopexy in elimination of visceral adhesion to repair site has been evaluated.     

Extraction of essential oils from damask rose using green and conventional techniques: Microwave and ohmic assisted hydrodistillation versus hydrodistillation

Damask rose is cultivated as the main species used in the production of rose water and relevant essential oils (EOs) of rose for its fragrance and therapeutic applications. Since the flowers are highly perishable, the extraction of oil should be done rapidly in order to produce rose EO successfully and optimally. Solvent free microwave-assisted extraction (SFME) and ohmic assisted hydrodistillation (OAHD) are advanced and green distillation techniques, which utilize microwave, and ohmic heating processes respectively for the extraction of EOs. In this study, SFME and OAHD of EOs were performed on fresh flowers of damask rose, and the findings were compared with the traditional hydrodistillation (HD). The findings of EO analysis indicated considerable alterations in EOs compounds extracted by SFME and OAHD methods compared with the traditional HD. To reach the desirable temperature of extraction (nearly 100 °C) and to get the first EO droplets’ evaporation with steam, the mixture was heated for 2.50 ± 0.29 min in SFME and for 17.33 ± 0.33 min in OAHD, while for the HD the heating had to take more than 40 min (42.66 ± 0.32 min). The total extraction time of EOs extracted from damask rose by using the green extraction procedures (SFME and OAHD) were compared with HD extraction method. Extraction by SFME occurred much earlier than extraction by OAHD. Also in this study, the analysis of EOs indicated that the chemical profile of damask rose may fluctuate quantitatively with respect to the constituents and structure of the extracted molecules. This would depend on the system of extraction that influences the characteristics of the EOs.     

Effects of chronic and acute ozone exposure on lipid peroxidation and antioxidant capacity in healthy young adults

BACKGROUND: There is growing evidence for the role of oxidative damage in chronic diseases. Although ozone (O3) is an oxidant pollutant to which many people are exposed, few studies have examined whether O3 induces oxidative stress in humans. OBJECTIVES: This study was designed to assess the effect of short-and long-term O(3) exposures on biomarkers of oxidative stress in healthy individuals. METHODS: Biomarkers of lipid peroxidation, 8-isoprostane (8-iso-PGF), and antioxidant capacity ferric reducing ability of plasma (FRAP) were analyzed in two groups of healthy college students with broad ranges of ambient O3 exposure during their lifetimes and previous summer recess either in Los Angeles (LA, n = 59) or the San Francisco Bay Area (SF, n = 61). RESULTS: Estimated 2-week, 1-month, and lifetime O3 exposures were significantly correlated with elevated 8-iso-PGF. Elevated summertime exposures resulted in the LA group having higher levels of 8-iso-PGF than the SF group (p = 0.02). Within each location, males and females had similar 8-iso-PGF. No regional difference in FRAP was observed, with significantly higher FRAP in males in both groups (SF: p = 0.002; LA: p = 0.004). An exposure chamber substudy (n = 15) also showed a significant increase in 8-iso-PGF as well as an inhibition of FRAP immediately after a 4-hr exposure to 200 ppb O3, with near normalization by 18 hr in both biomarkers. CONCLUSIONS: Long-term exposure to O3 is associated with elevated 8-iso-PGF, which suggests that 8-iso-PGF is a good biomarker of oxidative damage related to air pollution.     

Biorthogonal multiwavelets on the interval for solving multidimensional fractional optimal control problems with inequality constraint

This article proposes a new numerical approach for solving fractional optimal control problems including state and control inequality constraints using new biorthogonal multiwavelets. The properties of biorthogonal multiwavelets are first given. The Riemann-Liouville fractional integral operator for biorthogonal multiwavelets is utilized to reduce the solution of optimal control problems to a nonlinear programming one, to which existing, well-developed algorithms may be applied. In order to save the memory requirement and computation time, a threshold procedure is applied to obtain algebraic equations. The method is computationally very attractive and gives very accurate results.     

Do preoperative pulmonary function indices predict morbidity after coronary artery bypass surgery?

Context:

The reported prevalence of chronic obstructive pulmonary disease (COPD) varies among different groups of cardiac surgical patients. Moreover, the prognostic value of preoperative COPD in outcome prediction is controversial.

Aims:

The present study assessed the morbidity in the different levels of COPD severity and the role of pulmonary function indices in predicting morbidity in patients undergoing coronary artery bypass graft (CABG).

Settings and Design:

Patients who were candidates for isolated CABG with cardiopulmonary bypass who were recruited for Tehran Heart Center-Coronary Outcome Measurement Study.

Methods:

Based on spirometry findings, diagnosis of COPD was considered based on Global Initiative for Chronic Obstructive Lung Disease category as forced expiratory volume in 1 s [FEV1]/forced vital capacity <0.7 (absolute value, not the percentage of the predicted). Society of Thoracic Surgeons (STS) definition was used for determining COPD severity and the patients were divided into three groups: Control group (FEV1 >75% predicted), mild (FEV1 60–75% predicted), moderate (FEV1 50–59% predicted), severe (FEV1<50% predicted). The preoperative pulmonary function indices were assessed as predictors, and postoperative morbidity was considered the surgical outcome.

Results:

This study included 566 consecutive patients. Patients with and without COPD were similar regarding baseline characteristics and clinical data. Hypertension, recent myocardial infarction, and low ejection fraction were higher in patients with different degrees of COPD than the control group while male gender was more frequent in control patients than the others. Restrictive lung disease and current cigarette smoking did not have any significant impact on postoperative complications. We found a borderline P = 0.057 with respect to respiratory failure among different patients of COPD severity so that 14.1% patients in control group, 23.5% in mild, 23.4% in moderate, and 21.9% in severe COPD categories developed respiratory failure after CABG surgery.

Conclusion:

Among post-CABG complications, patients with different levels of COPD based on STS definition, more frequently developed respiratory failure. This finding may imply the prognostic value of preoperative pulmonary function test for determining COPD severity and postoperative morbidities.     

Five Years Survival of Patients After Liver Transplantation and Its Effective Factors by Neural Network and Cox Poroportional Hazard Regression Models

Background:

Transplantation is the only treatment for patients with liver failure. Since the therapy imposes high expenses to the patients and community, identification of effective factors on survival of such patients after transplantation is valuable.

Objectives:

The current study attempted to model the survival of patients (two years old and above) after liver transplantation using neural network and Cox Proportional Hazards (Cox PH) regression models. The event is defined as death due to complications of liver transplantation.

Patients and Methods:

In a historical cohort study, the clinical findings of 1168 patients who underwent liver transplant surgery (from March 2008 to march 2013) at Shiraz Namazee Hospital Organ Transplantation Center, Shiraz, Southern Iran, were used. To model the one to five years survival of such patients, Cox PH regression model accompanied by three layers feed forward artificial neural network (ANN) method were applied on data separately and their prediction accuracy was compared using the area under the receiver operating characteristic curve (ROC). Furthermore, Kaplan-Meier method was used to estimate the survival probabilities in different years.

Results:

The estimated survival probability of one to five years for the patients were 91%, 89%, 85%, 84%, and 83%, respectively. The areas under the ROC were 86.4% and 80.7% for ANN and Cox PH models, respectively. In addition, the accuracy of prediction rate for ANN and Cox PH methods was equally 92.73%.

Conclusions:

The present study detected more accurate results for ANN method compared to those of Cox PH model to analyze the survival of patients with liver transplantation. Furthermore, the order of effective factors in patients’ survival after transplantation was clinically more acceptable. The large dataset with a few missing data was the advantage of this study, the fact which makes the results more reliable.     

Decorated single-enantiomer phosphoramide-based silica/magnetic nanocomposites for direct enantioseparation

The nano-composites Fe₃O₄@SiO₂@(–O₃Si[(CH₂)₃NH])P( O)(NH-R(+)CH(CH₃)(C₆H₅))₂ (Fe₃O₄@SiO₂@PTA(+)) and Fe₃O₄@SiO₂@(–O₃Si[(CH₂)₃NH])P( O)(NH-S(−)CH(CH₃)(C₆H₅))₂ (Fe₃O₄@SiO₂@PTA(−)) were prepared and used for the chiral separation of five racemic mixtures (PTA = phosphoric triamide). The separation results show chiral recognition ability of these materials with respect to racemates belonging to different families of compounds (amine, acid, and amino-acid), which show their feasibility to be potential adsorbents in chiral separation. The nano-composites were characterized by FTIR, TEM, SEM, EDX, XRD, and VSM. The VSM curves of nano-composites indicate their superparamagnetic property, which is stable after their use in the separation process. Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@PTA(+) and Fe₃O₄@SiO₂@PTA(−) are regularly spherical with uniform shape and the average sizes of 17–20, 18–23, 36–47 and 43–52 nm, respectively.

The nano-composites Fe₃O₄@SiO₂@PTA(+) and Fe₃O₄@SiO₂@PTA(−) (PTA: phosphoric triamide) were prepared and used for the chiral separation of five racemic mixtures.     

Investigation of synergistic effects between silica nanoparticles,biosurfactant and salinity in simultaneous flooding for enhanced oil recovery

The purpose of this study was to investigate the effect of process parameters including silica nanoparticle (NP) concentration, biosurfactant (BS) concentration, and salinity as well as their synergistic effects on oil recovery in simultaneous flooding. Additionally, the effect of NP morphology (in the BS-NP solution) on oil recovery was investigated in this research. Micromodel flooding tests were designed with a central composite design (CCD) and carried out using BS and spherical silica NPs. The results showed that there is a positive synergistic effect between BS and silica NPs to shift the wettability to the water-wet condition and decrease interfacial tension (IFT), resulting in improved oil recovery. Indeed, the maximum oil recovery was obtained at an optimum salt concentration. Several micromodel tests were then carried out with BS and different-shaped NPs at the optimum point predicted by a mathematical model to study the effect of NP morphology on oil recovery. The results showed that minimum IFT of 1.85 mN m⁻¹ and the most reduction in the glass contact angle of 92.8% could be achieved by the BS-spherical NP solution as compared to those of the BS-non spherical NP solutions, which led to the highest oil recovery of 53.4%. The better performance of spherical NPs was attributed to the higher uniformity, which resulted in better distribution and more effective interactions with crude oil components. The results of core flooding tests showed that the BS-spherical NP solution yielded 26.1% final oil recovery after brine flooding. In addition, the BS-NP solution was more effective in wettability alteration of an oil-wet carbonate rock compared with the BS solution. It was deduced that the main mechanisms involved in oil recovery improvement were wettability alteration to the water-wet state, IFT reduction, and mobility ratio improvement.

The purpose of this study was to investigate the effect of process parameters (silica nanoparticle concentration (NP), biosurfactant (BS) concentration and salinity) as well as their synergistic effects on oil recovery in simultaneous flooding.