[Effect of low-dose ionizing radiation exposure on thyroid function in a medical occupational population]

Objective: We evaluated the effect of low-dose of ionizing radiation on thyroid function of medical occupational group with long-term exposure; furthermore; we analyzed the relationship between the thyroid hormones and the risk factors; such as exposure length; department. Ultimately; providing the scientific basis for setting the ionizing radiation protection standards. Methods: The population who engaged radiodiagnosis and radiotherapy in a tertiary-A hospital were set up as occupational exposure; 724 medical professionals as the research object. We figured out the basic information and general condition of the groups by face-to-face questionnaire survey; By means of the thyroid hormone testing; we analyzed the thyroid hormone levels with different population; occupational exposure factors. Then; obtained the prevalence of thyroid nodules by the thyroid ultrasound. Besides; we used the logistic regression model to analyze the risk factors related to thyroid nodule. Applying Epidata、Excel in data management. All the data was analyzed by statistical software package Stata12.0. Descriptive statistics; single factor analysis of variance and other statistical methods were used for data analysis. Test standard: α=0.05、P<0.05 statistical significant. Results: 1. Based on the work experience; we divided the study population into four groups; such as 1-9; 10-19; 20-29; and>30 years. The difference of the TSH level among the four groups was statistically significant (P<0.05) . 2. The multiple logistic regression showed that sex and seniority were the independent risk factors for the abnormal rate of thyroid nodules. Conclusion: Long-term exposure to low-dose ionizing radiatiom could induce the thyroid damage of medical occupational population; which should be broader concerned.

Low-p_{T} e^{+}e^{-} Pair Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV at STAR

We report first measurements of e^{+}e^{-} pair production in the mass region 0.4<M_{ee}<2.6  GeV/c^{2} at low transverse momentum (p_{T}<0.15  GeV/c) in noncentral Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p_{T} with a width (sqrt[⟨p_{T}^{2}⟩]) between 40 and 60  MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened ρ spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p_{T}^{2} distributions.

Strong negative nonlinear friction from induced two-phonon processes in vibrational systems

Self-sustained vibrations in systems ranging from lasers to clocks to biological systems are often associated with the coefficient of linear friction, which relates the friction force to the velocity, becoming negative. The runaway of the vibration amplitude is prevented by positive nonlinear friction that increases rapidly with the amplitude. Here we use a modulated electromechanical resonator to show that nonlinear friction can be made negative and sufficiently strong to overcome positive linear friction at large vibration amplitudes. The experiment involves applying a drive that simultaneously excites two phonons of the studied mode and a phonon of a faster decaying high-frequency mode. We study generic features of the oscillator dynamics with negative nonlinear friction. Remarkably, self-sustained vibrations of the oscillator require activation in this case. When, in addition, a resonant force is applied, a branch of large-amplitude forced vibrations can emerge, isolated from the branch of the ordinary small-amplitude response.

Negative linear friction is known to lead to self-sustained vibrations in many systems. Here, the authors show that when nonlinear negative friction in an electromechanical oscillator becomes larger than its positive linear counterpart such self-sustained vibrations require activation.

Morphology Influence of Nanoporous Nickel Phosphate on Intumescent Flame Retardant Polypropylene Composites

The morphology of nanoporous nickel phosphate (NP) has a close relationship with its properties, so in this work NP with needle-like and mushroom-like shape was synthesized. Then NP with needle-like and mushroom-like shape was applied in intumescent flame retardant polypropylene (PP) composites. With the addition of suitable content of NP, both mushroom-like and needle-like NP can improve the combustion and thermal properties of intumescent flame retardant PP composites. Needle-like NP shows a better thermal ant flame retardant synergist effect with intumescent flame retardants compared to mushroom-like NP. However, mushroom-like NP shows a better effect on smoke suppression. With the addition of suitable content of needle-like NP, the peak heat release rate of flame retardant PP composite decreases by 68.2 % comparing with that of the pure PP, and decreases by 23.8 % comparing with that of flame retardant PP composite without NP. The maximum weight loss temperature of PP composites can be increased from 408 °C to 485 °C with the addition of needle-like NP. Furthermore, the pyrolysis products of flame retardant PP composite with needle-like NP were investigated. From the research, it provides a further understanding of the influence on synergic effects in intumescent flame retardant systems.

Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.

Prognostic implication of EGFR mutation status and subtype in resected lung adenocarcinoma patients irrespective of therapy

OBJECTIVE

This study aimed to investigate the pure prognostic role of epidermal growth factor receptor (EGFR) mutation status and subtype in lung adenocarcinoma patients irrespective of therapy.

MATERIALS AND METHODS

We retrospectively enrolled 119 cases of completely resected pathological stage I lung adenocarcinoma patients who received no postoperative chemotherapy or tyrosine kinase inhibitors. EGFR gene mutations from 18 to 21 exons were tested for all the patients. Disease-free survival (DFS) and overall survival (OS) were compared between patients with different EGFR mutation status and subtype using Kaplan-Meier methods.

RESULTS

EGFR mutations were detected in 54 (45.4%) patients including two common mutation subtypes: 32 in-frame deletion within exon 19 (19del) and 19 point mutation within exon 21 (L858R). The frequency of EGFR mutations was much greater for patients of non-smokers versus current or ever smokers (58.1 versus 24.4%, P = 0.000), and a little greater for females versus males (53.8 versus 35.2%, P = 0.042). The median follow-up duration was 43.5 months, and there were no differences on DFS (P = 0.461) and OS (P = 0.989) between patients with EGFR mutations and those without in univariate analysis. The patients harboring 19del mutation had a better DFS (P = 0.028) and OS (P = 0.001) than the patients harboring L858R mutation with significant statistical difference.

CONCLUSIONS

This study suggests that there is no difference on survival between patients with EGFR mutations and those without, but the patients harboring EGFR 19del mutation have survival advantage compared to those harboring EGFR L858R mutation.

High stocking density alters bone-related calcium and phosphorus metabolism by changing intestinal absorption in broiler chickens

Live performance, bone health and metabolic responses to the interaction among stocking density and dietary concentrations of total calcium (TCa) and non-phytate phosphorus (NPP) were determined on 2,232 Ross 308 female broilers over a 3-wk experimental period. From 22 d of age, birds were randomly divided into 48 groups and provided with different corn-soybean meal-based diets varying in TCa (0.70% or 0.90%) and NPP (0.28% or 0.36%) content at 1 of 2 stocking densities [28.6 (LSD, 13 broilers/m2) and 39.6 (HSD, 18 broilers/m2) kg of predicted final BW/m2 floor space], according to a 2 × 2 × 2 factorial design with 6 replications in each treatment. Regardless of NPP supplementation, a high-TCa (0.90%) diet aggravated the impact of HSD on growth (BW gain and feed efficiency, P < 0.001) and motility (gait score, P < 0.001). This might be explained by deteriorating tibia quality (relative weight, mineral composition and biomechanical property; P < 0.01), due to the involvement of decreasing duodenal absorption (type IIb sodium-phosphate co-transporter mRNA, P < 0.001) in reduced phosphorus retention (P < 0.001). On the contrary, increasing dietary NPP (0.36%), particularly if high in TCa (0.90%), boosted TCa retention (P < 0.05) by improving absorption (calcium-binding protein D28k transcription, P < 0.05) for LSD chickens, hence enhancing bone development (relative tibia weight and tibia breaking strength, P < 0.05) and leg health (walking ability, P < 0.05). Together, HSD and LSD birds show an impaired TCa tolerance and a higher TCa+NPP threshold, respectively, to allow the optimization of bone quality via altered intestinal absorption.

[Prognostic value of pretreatment neutrophil-to-lymphocyte ratio (NLR) in locally advanced non-small cell lung cancer patients treated with thoracic radiation]

Objective: The aim of this retrospective study was to evaluate the prognostic significance of pretreatment Neutrophil-to-Lymphocyte Ratio(NLR) in locally advanced non-small cell lung cancer(NSCLC) patients treated with thoracic radiotherapy. Methods: We retrospectively analyze 420 patients who received thoracic radiotherapy alone, sequential chemoraiotherapy or concurrent chemoradiotherapy for locally advanced stage NSCLC from January 2007 to December 2010 of our hospital. The patients were divided into two groups (high NLR group and low NLR group) with appropriate cutoff point using the receiver operating characteristic (ROC) curve method. The survival curve was established by Kaplan-Meier method. The Log-rank test was used to compare the survival of the two NLR groups and the multivariate analysis was carried out by Cox regression model. Results: Among the 420 patients, 99 received radiotherapy alone, 139 received sequential chemoradiotherapy and 182 received concurrent chemoradiotherapy. 345 patients died and 75 were still alive. The median follow-up time was 5.2 years and the median overall survival was 22 months. The cut-off value of pretreatment NLR was 2.1. The 5-year PFS and OS rates in high NLR group and low NLR group were 10.6% vs 15.7% (P=0.033) and 15.5% vs 22.7% (P=0.012). Multivariate analysis confirmed that pretreatment NLR (hazard ratio 1.06, P=0.041) was independent prognostic factor of OS. Conclusions: Our study revealed that the pretreatment NLR is the independent prognostic factor of OS in patients with locally advanced stage NSCLC treated with thoracic radiotherapy. However, NLR is still greatly influenced by patient's condition and treatment which needs further research.

Predicting aged pork quality using a portable Raman device

The utility of Raman spectroscopic signatures of fresh pork loin (1 d & 15 d postmortem) in predicting fresh pork tenderness and slice shear force (SSF) was determined. Partial least square models showed that sensory tenderness and SSF are weakly correlated (R² = 0.2). Raman spectral data were collected in 6 s using a portable Raman spectrometer (RS). A PLS regression model was developed to predict quantitatively the tenderness scores and SSF values from Raman spectral data, with very limited success. It was discovered that the prediction accuracies for day 15 post mortem samples are significantly greater than that for day 1 postmortem samples. Classification models were developed to predict tenderness at two ends of sensory quality as "poor" vs. "good". The accuracies of classification into different quality categories (1st to 4th percentile) are also greater for the day 15 postmortem samples for sensory tenderness (93.5% vs 76.3%) and SSF (92.8% vs 76.1%). RS has the potential to become a rapid on-line screening tool for the pork producers to quickly select meats with superior quality and/or cull poor quality to meet market demand/expectations.