Cosmological HII Bubble Growth During Reionization

We present general properties of ionized hydrogen (HII) bubbles and their growth based on a state-of-the-art large-scale (100 Mpc/h) cosmological radiative transfer simulation. The simulation resolves all halos with atomic cooling at the relevant redshifts and simultaneously performs radiative transfer and dynamical evolution of structure formation. Our major conclusions include: (1) for significant HII bubbles, the number distribution is peaked at a volume of $\sim 0.6 {\rm Mpc^{3}/h^{3}}$ at all redshifts. But, at $z\le 10$, one large, connected network of bubbles dominates the entire HII volume. (2) HII bubbles are highly non-spherical. (3) The HII regions are highly biased with respect to the underlying matter distribution with the bias decreasing with time. (4) The non-gaussianity of the HII region is small when the universe becomes 50% ionized. The non-gaussianity reaches its maximal near the end of the reionization epoch $z\sim 6$. But at all redshifts of interest there is a significant non-gaussianity in the HII field. (5) Population III galaxies may play a significant role in the reionization process. Small bubbles are initially largely produced by Pop III stars. At $z\ge 10$ even the largest HII bubbles have a balanced ionizing photon contribution from Pop II and Pop III stars, while at $z\le 8$ Pop II stars start to dominate the overall ionizing photon production for large bubbles, although Pop III stars continue to make a non-negligible contribution. (6) The relationship between halo number density and bubble size is complicated but a strong correlation is found between halo number density and bubble size for large bubbles.Comment: 10 pages, 14 figures; accepted version; higher resolution figures and supplementary material can be found at http://www.astro.princeton.edu/~msshin/reionization/web.ht

Half-dose verteporfin photodynamic therapy for bullous variant of central serous chorioretinopathy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Central serous chorioretinopathy is characterized by serous neurosensory detachment of the macula and it usually resolves spontaneously with good visual prognosis. In some patients, however, the serous retinal detachment might be very extensive and can result in bullous exudative retinal detachment. We evaluated the use of half-dose verteporfin photodynamic therapy for the treatment of bullous retinal detachment in idiopathic central serous chorioretinopathy.</p> <p>Case presentation</p> <p>We report the case of a 51-year-old Chinese man who presented with blurred vision in his right eye and superior visual field defect due to bullous variant of central serous chorioretinopathy. No improvement in vision and retinal detachment was noted after three months of observation and a short course of oral acetazolamide. He was then treated with half-dose verteporfin photodynamic therapy and his visual acuity improved from 20/70 to 20/25 within one month of treatment. Three months after photodynamic therapy, there was complete resolution of sub-retinal fluid and bullous retinal detachment. No recurrence of central serous chorioretinopathy was noted in three years of follow-up.</p> <p>Conclusion</p> <p>We report the beneficial effect of photodynamic therapy with half-dose verteporfin as a treatment option for bullous retinal detachment caused by central serous chorioretinopathy.</p

International incidence of childhood cancer, 2001-10: a population-based registry study.

Cancer is a major cause of death in children worldwide, and the recorded incidence tends to increase with time. Internationally comparable data on childhood cancer incidence in the past two decades are scarce. This study aimed to provide internationally comparable local data on the incidence of childhood cancer to promote research of causes and implementation of childhood cancer control. This population-based registry study, devised by the International Agency for Research on Cancer in collaboration with the International Association of Cancer Registries, collected data on all malignancies and non-malignant neoplasms of the CNS diagnosed before age 20 years in populations covered by high-quality cancer registries with complete data for 2001-10. Incidence rates per million person-years for the 0-14 years and 0-19 years age groups were age-adjusted using the world standard population to provide age-standardised incidence rates (WSRs), using the age-specific incidence rates (ASR) for individual age groups (0-4 years, 5-9 years, 10-14 years, and 15-19 years). All rates were reported for 19 geographical areas or ethnicities by sex, age group, and cancer type. The regional WSRs for children aged 0-14 years were compared with comparable data obtained in the 1980s. Of 532 invited cancer registries, 153 registries from 62 countries, departments, and territories met quality standards, and contributed data for the entire decade of 2001-10. 385 509 incident cases in children aged 0-19 years occurring in 2·64 billion person-years were included. The overall WSR was 140·6 per million person-years in children aged 0-14 years (based on 284 649 cases), and the most common cancers were leukaemia (WSR 46·4), followed by CNS tumours (WSR 28·2), and lymphomas (WSR 15·2). In children aged 15-19 years (based on 100 860 cases), the ASR was 185·3 per million person-years, the most common being lymphomas (ASR 41·8) and the group of epithelial tumours and melanoma (ASR 39·5). Incidence varied considerably between and within the described regions, and by cancer type, sex, age, and racial and ethnic group. Since the 1980s, the global WSR of registered cancers in children aged 0-14 years has increased from 124·0 (95% CI 123·3-124·7) to 140·6 (140·1-141·1) per million person-years. This unique global source of childhood cancer incidence will be used for aetiological research and to inform public health policy, potentially contributing towards attaining several targets of the Sustainable Development Goals. The observed geographical, racial and ethnic, age, sex, and temporal variations require constant monitoring and research. International Agency for Research on Cancer and the Union for International Cancer Control

Internalization of Formyl Peptide Receptor in Leukocytes Subject to Fluid Stresses

Human leukocytes retract pseudopods under normal physiologic levels of fluid shear stress even in the absence of any other mediator. To gain more detailed understanding of the mechanisms that regulate this cell behavior, we exposed leukocytes to a steady state laminar shear field in a flow chamber and computed the fluid stresses distribution on the surface of individual cells with and without pseudopod. The surface fluid stress distribution on such cell is quite inhomogeneous. We hypothesized that the local fluid stresses on the cell surface serve to regulate pseudopod retraction by way of membrane receptors, especially the formyl peptide receptor (FPR). Comparison of the receptor distribution and the stress distribution over the surface of the cells indicates that the membrane fluid stress alone is not directly correlated with the extent of regional pseudopod retraction, giving further support to the hypothesis that membrane receptors are involved in the mechanotransduction of leukocytes. We observed that after exposure to fluid shear the FPR was internalized to a small intracellular compartment. This internalization appears to be independent of the original location of the receptor on the surface of the cell and the FPR appears to be more derived from multiple locations on the cell, with both higher and lower fluid stresses. The evidence suggests that FPR involvement in the pseudopod-retraction process is not limited to cell surface regions with the highest fluid shear stress, but rather a more global occurrence over the majority of the cell membrane

High-efficiency photovoltaic cells with wide optical band gap polymers based on fluorinated phenylene-alkoxybenzothiadiazole

A series of semi-crystalline, wide band gap (WBG) photovoltaic polymers were synthesized with varying number and topology of fluorine substituents. To decrease intramolecular charge transfer and to modulate the resulting band gap of D-A type copolymers, electron-releasing alkoxy substituents were attached to electron-deficient benzothiadiazole (A) and electron-withdrawing fluorine atoms (0-4F) were substituted onto a 1,4-bis(thiophen-2-yl)benzene unit (D). Intra- and/or interchain noncovalent Coulombic interactions were also incorporated into the polymer backbone to promote planarity and crystalline intermolecular packing. The resulting optical band gap and the valence level were tuned to 1.93-2.15 eV and -5.37 to -5.67 eV, respectively, and strong interchain organization was observed by differential scanning calorimetry, high-resolution transmission electron microscopy and grazing incidence X-ray scattering measurements. The number of fluorine atoms and their position significantly influenced the photophysical, morphological and optoelectronic properties of bulk heterojunctions (BHJs) with these polymers. BHJ photovoltaic devices showed a high power conversion efficiency (PCE) of up to 9.8% with an open-circuit voltage of 0.94-1.03 V. To our knowledge, this PCE is one of the highest values for fullerene-based single BHJ devices with WBG polymers having a band gap of over 1.90 eV. A tandem solar cell was also demonstrated successfully to show a PCE of 10.3% by combining a diketopyrrolopyrrole-based low band gap polymer

Comparison Of Reionization Models: Radiative Transfer Simulations And Approximate, Semi-Numeric Models

We compare the predictions of four different algorithms for the distribution of ionized gas during the Epoch of Reionization. These algorithms are all used to run a 100 Mpc/h simulation of reionization with the same initial conditions. Two of the algorithms are state-of-the-art ray-tracing radiative transfer codes that use disparate methods to calculate the ionization history. The other two algorithms are fast but more approximate schemes based on iterative application of a smoothing filter to the underlying source and density fields. We compare these algorithms' resulting ionization and 21 cm fields using several different statistical measures. The two radiative transfer schemes are in excellent agreement with each other (with the cross-correlation coefficient of the ionization fields >0.8 for k < 10 h/Mpc and in good agreement with the analytic schemes (>0.6 for k < 1 h/Mpc). When used to predict the 21cm power spectrum at different times during reionization, all ionization algorithms agree with one another at the 10s of percent level. This agreement suggests that the different approximations involved in the ray tracing algorithms are sensible and that semi-numerical schemes provide a numerically-inexpensive, yet fairly accurate, description of the reionization process.Comment: 13 pages, 10 figure

Impact of N on the atomic-scale Sb distribution in quaternary GaAsSbN-capped InAs quantum dots

The use of GaAsSbN capping layers on InAs/GaAs quantum dots (QDs) has recently been proposed for micro- and optoelectronic applications for their ability to independently tailor electron and hole confinement potentials. However, there is a lack of knowledge about the structural and compositional changes associated with the process of simultaneous Sb and N incorporation. In the present work, we have characterized using transmission electron microscopy techniques the effects of adding N in the GaAsSb/InAs/GaAs QD system. Firstly, strain maps of the regions away from the InAs QDs had revealed a huge reduction of the strain fields with the N incorporation but a higher inhomogeneity, which points to a composition modulation enhancement with the presence of Sb-rich and Sb-poor regions in the range of a few nanometers. On the other hand, the average strain in the QDs and surroundings is also similar in both cases. It could be explained by the accumulation of Sb above the QDs, compensating the tensile strain induced by the N incorporation together with an In-Ga intermixing inhibition. Indeed, compositional maps of column resolution from aberration-corrected Z-contrast images confirmed that the addition of N enhances the preferential deposition of Sb above the InAs QD, giving rise to an undulation of the growth front. As an outcome, the strong redshift in the photoluminescence spectrum of the GaAsSbN sample cannot be attributed only to the N-related reduction of the conduction band offset but also to an enhancement of the effect of Sb on the QD band structure

Impact of Grade, Hormone Receptor, and HER-2 Status in Women with Breast Cancer on Response to Specific Chemotherapeutic Agents by in vitro Adenosine Triphosphate-based Chemotherapy Response Assay

This study was designed to assess whether histological and biological factors of breast cancer can predict chemoresponse to specific agents. Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) was employed to retrieve chemoresponse to 5-fluorouracil (5-FU), doxetaxel, doxorubicin, epirubicin, and paclitaxel in 49 patients. Tumors with high histologic and nuclear grade have higher response rate to doxorubicin (P<0.05) and palitaxel (P<0.05). Estrogen receptor (ER)-negative tumors respond well to doxorubicin (P=0.038), and progesterone receptor (PR)-negative tumors to 5-FU (P=0.039), doxetaxel (P=0.038), doxorubicin (P=0.000), epirubicin (P=0.010), and paclitaxel (P=0.003). Among the breast cancer subtypes determined by ER, PR, and HER-2 immunohistochemical stains, the HER-2+/ER- subtype has a higher response rate to doxorubicin (P=0.008). This in vitro result suggests that the combination of histologic and nuclear grade, hormone receptor, and HER-2 status can be a predictive factor of response to specific chemotherapy agents. Further in vivo study should be followed for clinical trials