Role of hormonal and environmental factors on early incidence of breast cancer in Iran

Although the probability of having breast cancer increases with the age in general, this malignancy affects Iranian women at least one decade younger than their counterparts in other countries. However the underlying risk factors for the discrepancy have not been identified. The aryl hydrocarbon receptor (AhR) mediates the effects of many environmental endocrine disruptors and contributes to the loss of normal ovarian function in polluted environments. This study was aimed to compare the interactions between AhR and other fundamental genes (p53, K-Ras, ER, PgR) in a clinical setting. To conduct the immunohistochemical studies using appropriate monoclonal antibodies, 25 premenopausal invasive ductal carcinoma, 29 postmenopausal invasive ductal carcinoma and 30 breast fibroadenoma were selected retrospectively from 2004 to 2007 in the pathology department of Imam Khomeini hospital complex of Tehran University of Medical Sciences . Higher levels of AhR in epithelial cells of premenopausal patients and breast fibroadenoma emphasized the susceptibility of these cells to environmental-induced tumors. AhR overexpression contributed to ER-/PgR-immunophenotype in young/premenopausal patients but the same pattern was not observed in benign and postmenopausal malignant tumors. It seems that early incidence of breast cancer in Iran is the result of interactions between hormonal and environmental factors.     

Effect of Y2O3 and Er2O3 co-dopants on phase stabilization of bismuth oxide

Bi₂O₃ compositions were prepared to investigate the effect of rare earth metal oxides as co-dopants on phase stability of bismuth oxide. Compositions containing 9-14 mol% of Y₂O₃ and Er₂O₃ were synthesized by solid state reaction. The structural characterization was carried out using X-ray powder diffraction. The XRD results show that the samples containing 12 and 14 mol% total dopants had cubic structure, whereas the samples with lower dopant concentrations were tetragonal. Comparing the lattice parameters of the cubic phases of (Bi₂O₃)_0.88(Y₂O₃)_0.06(Er₂O₃)_0.06 and (Bi₂O₃)_0.86(Y₂O₃)_0.07(Er₂O₃)_0.07 revealed that lattice parameter decreases by increasing the dopant concentration. The XRD pattern and the powder density results indicated the formation of solid solution in the studied systems. After annealing samples with cubic phase at 600 °C for various periods of time, phase transformation to tetragonal and rhombohedral occurs.     

The effect of gelatin and thymol-loaded nanostructured lipid carrier on physicochemical,rheological, and sensory properties of sesame paste/date syrup blends as a snack bar

The development of a novel snack bar based on sesame paste (SP) and date syrup (DS) was investigated. The aim of this study was to evaluation the effects of SP/DS ratio and encapsulated thymol (thymol-loaded nanostructured lipid carrier [TNLC]) on physicochemical, textural, rheological, and sensorial properties of snack bars. The effect of butylated hydroxytoluene (BHT), thymol, and TNLC showed that the addition of 100 ppm TNLC could improve the oxidative stability of SP/DS mixtures even better than BHT, while a higher concentration of TNLC had a negative effect. The unpleasant taste and odor of thymol could be overcome by its encapsulation in nanostructured lipid carriers. The textural properties of the formulations with different SP/DS ratios (1:2, 1:1, 2:1) and an overall concentration of 7 g of gelatin/kg of mixtures were evaluated. The texture profile analysis showed that the sample with an SP/DS ratio of 1:1 had higher hardness, adhesiveness, springiness, cohesiveness, and gumminess in comparison with the other ratios. From the sensory evaluation data, the bar prepared with an SP/DS ratio of 1:1 had the most acceptable texture. According to the results, the SP/DS ratio of 1:1 with gelatin and 100 ppm TNLC can be used in developing SP/DS blends as a highly acceptable functional food.     

Thermal diffusivity measurement of Au nanofluids of very low concentration by using photoflash technique

In this paper, the application of photoflash technique to measuring the thermal diffusivity of gold nanofluids of very low concentration at room temperature was presented. The nanofluid samples were prepared from the pulse laser ablation procedure. The thermal diffusivity was obtained by fitting the theoretical temperature signal to the experimental data, and it was found to increase linearly from 1.47 × 10⁻³ cm² s⁻¹ to 1.68 × 10⁻³ cm² s⁻¹ as the concentration increased from 1.11 mg/L to 3.18 mg/L. The increase in thermal diffusivity in these multidispersed nanofluids was attributed to the higher nanoparticle concentration as well as to the increasing presence of the smaller size nanoparticles.     

Fabrication of a bimetallic Cu/Pt particle-modified carbon nanotube paste electrode and its use for the electrocatalytic oxidation of methanol

In this work, carbon nanotube paste electrode (CNTPE) was used as a substrate for deposition of bimetallic Cu/Pt particles. At first, a Cu film was prepared by electrochemical reduction of Cu ions onto the CNTPE in 0.1 M H₂SO₄ solution. Cu/Pt catalysts were prepared by partial galvanic replacement of Cu with Pt by simply immersion of the Cu-coated CNTPE in 2.0 mM H₂PtCl₆ solution. The nature and surface morphology of the bare CNTPE and fabricated Cu/Pt species were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. The Cu/Pt-modified CNTPE exhibits remarkable electrocatalytic activity towards methanol oxidation. It has been shown that carbon nanotubes improve the electrocatalytic activity of the catalysts towards oxidation. Then, the influence of various parameters such as Cu source concentration, electrodeposition time, replacement time, and methanol concentration on its oxidation as well as long-term stability of the modified electrode have been investigated by electrochemical methods.     

Heat Transfer Enhancement in Shell-and-Tube Heat Exchangers Using Porous Media

A numerical simulation has been carried out to investigate the heat transfer enhancement in a shell-and-tube heat exchanger using a porous medium inside its shell and tubes, separately. A three-dimensional geometry with k-? turbulent model is used to predict the heat transfer and pressure drop characteristics of the flow. The effects of porosity and dimensions of these media on the heat exchanger's thermal performance and pressure drop are analyzed. Inside the shell, the entire tube bundle is wrapped by the porous medium, whereas inside the tubes the porous media are located in two different ways: (1) at the center of the tubes, and (2) attached to the inner wall of the tubes. The results showed that this method can improve the heat transfer at the expense of higher pressure drop. Evaluating the method showed that using porous media inside the shell, with particular dimension and porosity can increase the heat transfer rate better than pressure drop. Using this method inside the tubes leads to two diverse results: In the first configuration, pressure loss prevails over the heat transfer augmentation and it causes energy loss, whereas in the second configuration a great performance enhancement is observed.     

Self-assembled nanomicelles using PLGA–PEG amphiphilic block copolymer for insulin delivery: a physicochemical investigation and determination of CMC values

Self-assembled nanomicelles can be used as synthetic biomaterials and colloidal carriers for poorly water-soluble drug delivery systems. Some of these micellar systems have been introduced in clinical trials and showed hopeful results relating to their therapeutic index in patients. Biodegradable nanomicelle was prepared from self-assembling amphiphilic block copolymer composed of poly(dl-lactic-co-glycolic acid) (PLGA) as a core and polyethylene glycol (PEG) as a corona. The PLGA–PEG block copolymer was first synthesized and characterized by FTIR, ¹H NMR, GPC and inherent viscosity measurements. The nanomicelle formed by PLGA–PEG block copolymer in the aqueous solution was characterized by dynamic light scattering, zeta potential, scanning electron microscopy (SEM) and fluorescence excitation and emission spectra of pyrene probe. The critical micelle concentration of obtained nanomicelle was about 0.006 mg/mL, with the size of about 160 nm and the zeta potential of −29 mV. Insulin-loaded PLGA–PEG nanomicelles were prepared by modified dialysis method and the physicochemical parameters of the micelles such as drug content, entrapment efficiency and in vitro drug release were characterized. The results showed that insulin was entrapped into PLGA–PEG nanomicelles with drug loading of 3.9 wt% and entrapment efficiency of 55 wt%. The nanomicelles containing insulin exhibited a controlled release profile. These observations suggested that the PLGA–PEG block copolymers nanomicelles have been prepared by a new synthetic route are potent nanocarrier for poorly water-soluble drugs as insulin.     

Field Enhancement in Metamaterial Split Ring Resonator Aperture Nano-Antenna with Spherical Nano-Particle Arrangement

Silicon - In this paper, we present a split ring resonator (SRR) for a nano-aperture antenna for biomedical and spectroscopy applications. We have shown that while the graphene coat layer is...