Spectral Shift Originating from Non-linear Ultrasonic Wave Propagation and Its Effect on Imaging Resolution

An amplitude-dependent downshift in the fundamental wave spectrum of a propagating ultrasonic pulse caused by non-linear wave propagation is described. The effects of non-linearity and the associated downshift on spatial resolution are also studied. The amounts of downshift and spatial resolution are extracted from the numerically simulated beam profile based on the KZK equation. Results for a 25-MHz transducer reveal that non-linear effects can lead to 58% additional downshift in the centre frequency of a pulse compared with a linear case with downshift caused only by attenuation. This additional downshift causes about 50% degradation in axial resolution. However, as the beam becomes narrower from the non-linear effects, the overall effect of non-linearity still leads to improved lateral resolution (≤26%). Therefore, as non-linearity increases with wave pressure, it is concluded that the increase in source pressure improves lateral resolution and degrades axial resolution.     

Investigating the Antiangiogenic,Anti-drug Resistance and Apoptotic Effects of Soy Isoflavone Extract Alone or in Combination with Docetaxel on Murine 4T1 Breast Tumor Model

Background: One major concern in the treatment of cancer patients during chemotherapy is drug resistance. Here we investigated the effects of soy isoflavone extracts alone or in combination with Docetaxel on the drug resistance, angiogenesis, apoptosis, and tumor volume in mouse 4T1 breast tumor model. Methods: Sixty female BALB/c mice were randomly divided into 4 groups: control, dietary soy isoflavone extract [Iso, 100 mg/kg diet (0.01%)], Docetaxel (10 mg/kg) injection, and the combination of dietary soy isoflavone extract and intravenous Docetaxel injection (Docetaxel + Iso). One week after the third injection, the breast tumors of eight mice from each group were excised to analyze NF-κBp65′ vascular endothelial growth factor receptor-2 (VEGFR2) and Pgp gene and protein expressions and the other seven mice were monitored for survival rate analysis until they died. Results: NF-κBp65 gene and protein expressions were significantly lower in the Docetaxel + Iso group in comparison with that of the Docetaxel group. VEGFR2 protein expression in the Docetaxel + Iso and Iso groups was significantly lower than that of the Docetaxel group. Conclusion: These findings may indicate that the combined use of isoflavone extracts together with chemotherapeutic agents has more efficient anti-carcinogenic effects than their individual use.     

Do men with normal testosterone–oestradiol ratios benefit from letrozole for the treatment of male infertility?

Research question

Previous studies of aromatase inhibitors on male infertility have focused on men with low testosterone–oestradiol ratio of less than 10. Can aromatase inhibitors improve spermatogenesis in men with idiopathic male infertility with normal testosterone–oestradiol ratio?

Association of Metacognitive Beliefs,Obsessive Beliefs and Symptom Severity With Quality of Life in Obsessive–Compulsive Patients

The aim of this study was to evaluate the association of obsessive beliefs, obsessive–compulsive disorder severity and metacognitive beliefs to the quality of life in patients with obsessive–compulsive disorder (OCD). Sixty one adults with a principal diagnosis of OCD were recruited for the study. Participants were assessed by trained clinicians using an unstructured clinical interview, the Obsessive Beliefs Questionnaire, the Yale–Brown Obsessive–Compulsive Scale, the Metacognitive Beliefs Questionnaire and the WHO Quality of Life Questionnaire. Data were analyzed using Pearson's of correlation coefficients and multiple regression analyses. Findings indicate that obsessive beliefs, severity total OCD and metacognitive beliefs were associated with total quality of life scores. Regression analysis revealed that while OCD total severity explained 40.1% of the variance in total quality of life, obsessive beliefs (perfectionism/certainty domain) and metacognitions (cognitive self-consciousness and negative beliefs about thoughts in general) explained an additional 13.7%, 7.7% and 5.4% of the variance in QoL. Findings indicate that the metacognitive beliefs associated with OCD symptom severity are different from that associated with quality of life. The implications are that metacognitive therapy aimed at symptom reduction may not necessarily result in improved QoL in OCD patients.