Effect of hexagonal structure nanoparticles on the morphological performance of the ceramic scaffold using analytical oscillation response

Porous bony scaffolds are utilized to manage the growth and migration of cells from adjacent tissues to a defective position. In the current investigation, the effect of titanium oxide (TiO₂) nanoparticles on mechanical and physical properties of porous bony implants made of polymeric polycaprolactone (PCL) is studied. The bio-nanocomposite scaffolds are prepared with composition of nanocrystalline hydroxyapatite (HA) and TiO₂ powder using the freeze-drying technique for different weight fractions of TiO₂ (0 wt%, 5 wt%, 10 wt%, and 15 wt%). In order to identify the microstructure and morphology of the fabricated porous bio-nanocomposites, the X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM) are employed. Also, the biocompatibility and biodegradability of the manufactured scaffolds are examined by placing them in a simulated body fluid (SBF) for 21 days, their weight and pH changes are measured. The rate of degradation of the PCL-HA scaffold can be controlled by varying the percentage of its constituent components. Due to an increasing growth and activity of bone cells and the apatite formation on the free surface of the fabricated bio-nanocomposite implants as well as their reasonable mechanical properties, they have the potential to be used as a bone substitute. Additionally, with the aid of the experimentally extracted mechanical properties of the scaffolds, the vibrational characteristics of a beam-type implant made of the proposed porous bio-nanocomposites are explored. The results obtained from SEM image indicate that the scaffolds produced by the employed method have high total porosity (70%–85%) and effective porosity. The pore size is obtained between 60 and 200 μm, which is desirable for the growth and propagation of bone cells. Also, it is revealed that the addition of TiO₂ nanoparticles leads to reduce the rate of dissolution of the fabricated bio-nanocomposite scaffolds.     

Lighting preferences in office spaces concerning the indoor thermal environment

The accurate prediction of the visual comfort zone in an indoor environment is difficult as it depends on many parameters. This is especially the case for large compact urban areas in which the density and shadow from neighboring buildings can limit the accessible daylighting in indoor spaces. This paper investigates the satisfaction range for illuminance regarding indoor air temperature in office buildings and the significant parameters affecting this range in six office buildings in Tehran, Iran. Lighting comfort has been evaluated by a subjective survey (509 total responses) and field measurement. The questionnaires were filled out in 146 and 109 rooms in summer and winter, respectively. The results show that the illuminance should not be less than 550 lx, while illuminance between 600 and 650 lx provides the highest satisfaction level. The satisfaction with lighting level is affected by individual parameters such as age, type of activity, and environmental parameters such as window orientation, external obscurations, and season. A relationship was observed between lighting level satisfaction and thermal condition acceptance, and the overall comfort depends more on thermal conditions than the lighting level.     

A new hybrid chaotic atom search optimization based on tree-seed algorithm and Levy flight for solving optimization problems

Engineering with Computers - Optimizing the high computational real-world problems is a challenging task that has taken a great deal of efforts in the last decade. The meta-heuristic algorithms...     

Preclinical Evaluation of 99mTc-ZHER2:41071, a Second-Generation Affibody-Based HER2-Visualizing Imaging Probe with a Low Renal Uptake

Radionuclide imaging of HER2 expression in tumours may enable stratification of patients with breast, ovarian, and gastroesophageal cancers for HER2-targeting therapies. A first-generation HER2-binding affibody molecule [^99mTc]Tc-ZHER2:V2 demonstrated favorable imaging properties in preclinical studies. Thereafter, the affibody scaffold has been extensively modified, which increased its melting point, improved storage stability, and increased hydrophilicity of the surface. In this study, a second-generation affibody molecule (designated ZHER2:41071) with a new improved scaffold has been prepared and characterized. HER2-binding, biodistribution, and tumour-targeting properties of [^99mTc]Tc-labelled ZHER2:41071 were investigated. These properties were compared with properties of the first-generation affibody molecules, [^99mTc]Tc-ZHER2:V2 and [^99mTc]Tc-ZHER2:2395. [^99mTc]Tc-ZHER2:41071 bound specifically to HER2 expressing cells with an affinity of 58 ± 2 pM. The renal uptake for [^99mTc]Tc-ZHER2:41071 and [^99mTc]Tc-ZHER2:V2 was 25–30 fold lower when compared with [^99mTc]Tc-ZHER2:2395. The uptake in tumour and kidney for [^99mTc]Tc-ZHER2:41071 and [^99mTc]Tc-ZHER2:V2 in SKOV-3 xenografts was similar. In conclusion, an extensive re-engineering of the scaffold did not compromise imaging properties of the affibody molecule labelled with ^99mTc using a GGGC chelator. The new probe, [^99mTc]Tc-ZHER2:41071 provided the best tumour-to-blood ratio compared to HER2-imaging probes for single photon emission computed tomography (SPECT) described in the literature so far. [^99mTc]Tc-ZHER2:41071 is a promising candidate for further clinical translation studies.     

The effect of hydrolysed tragacanth gum and inulin on the probiotic viability and quality characteristics of low‐fat yoghurt

This study investigates the effect of supplementation of tragacanth gum (GT, 0.05% w/v), low molecular weight gum tragacanth (LMWGT, 0.5% w/v) and inulin (0.5% w/v) on the viability of Bifidobacterium bifidum and the quality parameters of low‐fat yoghurt during a three‐week storage period. The count of probiotics was found to be 7.8 log cfu/g in inulin, and LMWGT enriched yoghurts at the end of the storage period. The minimum water holding capacity and the maximum syneresis values were also obtained in the low‐fat yoghurt enriched with GT throughout the storage time. The samples containing inulin and LMWGT revealed sensory attributes that were judged superior compared to those in GT.