Noise characterization for resonantly-enhanced polarimetric vacuum magnetic-birefringence experiments

In this work we present data characterizing the sensitivity of the Bir\'{e}fringence Magnetique du Vide (BMV) instrument. BMV is an experiment attempting to measure vacuum magnetic birefringence (VMB) via the measurement of an ellipticity induced in a linearly polarized laser field propagating through a birefringent region of vacuum in the presence of an external magnetic field. Correlated measurements of laser noise alongside the measurement in the main detection channel allow us to separate measured sensing noise from the inherent birefringence noise of the apparatus. To this end we model different sources of sensing noise for cavity-enhanced polarimetry experiments, such as BMV. Our goal is to determine the main sources of noise, clarifying the limiting factors of such an apparatus. We find our noise models are compatible with the measured sensitivity of BMV. In this context we compare the phase sensitivity of separate-arm interferometers to that of a polarimetry apparatus for the discussion of current and future VMB measurements

Parathyroid hormone levels predict posttotal thyroidectomy hypoparathyroidism

We hypothesized that parathyroid hormone (PTH) determination would be the most effective strategy to identify posttotal thyroidectomy hypoparathyroidism (PTTHP) compared with other clinical and laboratory parameters. We retrospectively reviewed our recent experience with total thyroidectomy. We recorded demographics, malignancy, thyroid weight, parathyroid autotransplantation, hospital stay, use of postoperative calcium and hormonally active vitamin D3 (calcitriol), and postoperative serum calcium and PTH levels. Patients were divided into two groups depending on whether supplemental calcitriol was required to maintain eucalcemia and therefore reflecting the diagnosis of PTTHP. From October 2010 to June 2013, a total of 202 total thyroidectomies were performed. Twentyfour patients (12%) developed PTTHP and required calcitriol replacement. Logistic regression analysis revealed that only postoperative calcium levels (P 5 0.02) and PTH levels (P\0.0001) statistically significantly predicted PTTHP. Twenty-two of 29 patients with PTH 13 pg/mL or less had PTTHP. Only two of 173 patients with a PTH level greater than 13 pg/mL were diagnosed with PTTHP. We recommend using PTH levels after total thyroidectomy to determine which patients will have hypoparathyroidism requiring calcitriol therapy. An early determination of PTTHP allows for prompt management that can shorten hospital stay and improve outcomes

Titanium dioxide nanoparticles activate the ATM-Chk2 DNA damage response in human dermal fibroblasts

The use of nanoparticles in consumer products increases their prevalence in the environment and the potential risk to human health. Although recent studies have shown in vivo and in vitro toxicity of titanium dioxide nanoparticles (nano-TiO(2)), a more detailed view of the underlying mechanisms of this response needs to be established. Here the effects of nano-TiO(2) on the DNA damage response and DNA replication dynamics were investigated in human dermal fibroblasts. Specifically, the relationship between nano-TiO(2) and the DNA damage response pathways regulated by ATM/Chk2 and ATR/Chk1 were examined. The results show increased phosphorylation of H2AX, ATM, and Chk2 after exposure. In addition, nano-TiO(2) inhibited the overall rate of DNA synthesis and frequency of replicon initiation events in DNA combed fibers. Taken together, these results demonstrate that exposure to nano-TiO(2) activates the ATM/Chk2 DNA damage response pathway