Can accreting primordial black holes explain the excess radio background?

The excess radio background seen at $\simeq 0.1-10\,{\rm GHz}$ has stimulated much scientific debate in the past years. Recently, it was pointed out that the soft photon emission from accreting primordial black holes may be able to explain this signal. We show that the expected ultraviolet photon emission from these accreting black holes would ionize the universe completely at $z>6$ and thus wash out the 21 cm absorption signature at $z\simeq$ 20 as well as be in tension with existing cosmic microwave background anisotropy and average spectral distortion limits. We discuss possible augmentations of the model; however, it seems that an explanation of radio excess by accreting primordial black holes is not well-justified.Comment: Accepted versio

Decaying turbulence in molecular clouds: how does it affect filament networks and star formation?

The fragmentation of gas to form stars in molecular clouds is intrinsically linked to the turbulence within them. These internal motions are set at the birth of the cloud and may vary with galactic environment and as the cloud evolves. In this paper, we introduce a new suite of 15 high-resolution molecular cloud simulations using the moving mesh code AREPO, to investigate the role of different decaying turbulent modes (mixed, compressive and solenoidal) and Virial ratios on the evolution of a $10^4\mathrm{M}_{\odot}$ molecular cloud. We find that diffuse regions maintain a strong relic of the initial turbulent mode, whereas the initial gravitational potential dominates dense regions. Solenoidal seeded models thus give rise to a diffuse cloud with filament-like morphology, and an excess of brown dwarf mass fragments. Compressive seeded models have an early onset of star-formation, cluster-like morphologies and a higher accretion rate, along with overbound clouds, compared to other simulations. Filaments identified using DisPerSE, and analyzed through a new Python toolkit we develop and make publicly available with this work called FIESTA, show no clear trend in lengths, masses and densities between initial turbulent modes. Overbound clouds, however, produce more filaments and thus have more mass in filaments. The hubs formed by converging filaments are found to favour star-formation, with surprisingly similar mass distributions independent of the number of filaments connecting the hub.Comment: 19 pages, 15 figure

Neonatal diethylstilbestrol exposure alters the metabolic profile of uterine epithelial cells

Developmental exposure to diethylstilbestrol (DES) causes reproductive tract malformations, affects fertility and increases the risk of clear cell carcinoma of the vagina and cervix in humans. Previous studies on a well-established mouse DES model demonstrated that it recapitulates many features of the human syndrome, yet the underlying molecular mechanism is far from clear. Using the neonatal DES mouse model, the present study uses global transcript profiling to systematically explore early gene expression changes in individual epithelial and mesenchymal compartments of the neonatal uterus. Over 900 genes show differential expression upon DES treatment in either one or both tissue layers. Interestingly, multiple components of peroxisome proliferator-activated receptor-γ (PPARγ)-mediated adipogenesis and lipid metabolism, including PPARγ itself, are targets of DES in the neonatal uterus. Transmission electron microscopy and Oil-Red O staining further demonstrate a dramatic increase in lipid deposition in uterine epithelial cells upon DES exposure. Neonatal DES exposure also perturbs glucose homeostasis in the uterine epithelium. Some of these neonatal DES-induced metabolic changes appear to last into adulthood, suggesting a permanent effect of DES on energy metabolism in uterine epithelial cells. This study extends the list of biological processes that can be regulated by estrogen or DES, and provides a novel perspective for endocrine disruptor-induced reproductive abnormalities

Study of metastasis in lymph node by fine needle aspiration cytology: our institutional experience

Background:Fine needle aspiration cytology (FNAC) is a reliable as well as an inexpensive diagnostic method. It is suitable for the developing countries for the diagnosis of lymphadenopathy at any approachable site. Fine needle aspiration cytology not only confirms the presence of metastatic disease but also, in most cases, gives the clue regarding the origin of the primary tumor, prognosis as well in the management of patient for staging purposes. The aim of the study was to detect and diagnose metastasis in lymph nodes. Methods:A study was done of all metastatic lymph node lesions reported in Department of Pathology, Govt. Medical College, Surat from May 2011 to April 2012.Results:A total of 2355 cases of fine needle aspiration cytology were carried out of which 580 cases were of lymph node. Cytology results were positive for metastasis in 157 specimens (27.06%). The most common site was cervical lymph nodes. Maximum numbers of cases of metastatic tumors were in 41-50 yrs age group. There were 115 males and 42 females with a male predominance (Male:Female= 2.8:1). The most common malignancy was squamous cells carcinoma, seen in 118 cases (75.15%), followed by metastatic mammary carcinoma (13 cases, 8.29%). In 26 cases out of 580 cases, histopathological confirmation was done and diagnostic accuracy of FNAC was 100%. Conclusions:Fine needle aspiration cytology of lymphadenopathy is a useful tool in diagnosing metastatic lesions with good certainty

Congenital diaphragmatic hernia in a patient with tetrasomy 9p

Tetrasomy of the short arm of chromosome 9 constitutes a rare condition resulting in a well clinically recognized syndrome. In our case, in addition to the characteristic phenotype at birth, the existence of a hernia-type Bochdalek diaphragmatic defect was found. Cytogenetic analysis revealed a nonmosaic case of an isochromosome of the entire short arm of chromosome 9 with no involvement of the heterochromatic region of the long arm: 47, XX, +i (9p). Because chromosome 9 contains several gene locus for enzymes and receptors of the retinoid pathway, this case potentially contributes to retinoid hypothesis in the etiology of congenital diaphragmatic hernia