Transposable elements maintain genome-wide heterozygosity in inbred populations.

Elevated levels of inbreeding increase the risk of inbreeding depression and extinction, yet many inbred species are widespread, suggesting that inbreeding has little impact on evolutionary potential. Here, we explore the potential for transposable elements (TEs) to maintain genetic variation in functional genomic regions under extreme inbreeding. Capitalizing on the mixed mating system of Arabidopsis lyrata, we assess genome-wide heterozygosity and signatures of selection at single nucleotide polymorphisms near transposable elements across an inbreeding gradient. Under intense inbreeding, we find systematically elevated heterozygosity downstream of several TE superfamilies, associated with signatures of balancing selection. In addition, we demonstrate increased heterozygosity in stress-responsive genes that consistently occur downstream of TEs. We finally reveal that TE superfamilies are associated with specific signatures of selection that are reproducible across independent evolutionary lineages of A. lyrata. Together, our study provides an important hypothesis for the success of self-fertilizing species

On the Connection of Anisotropic Conductivity to Tip Induced Space Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs

The electronic properties of shallow acceptors in p-doped GaAs{110} are investigated with scanning tunneling microscopy at low temperature. Shallow acceptors are known to exhibit distinct triangular contrasts in STM images for certain bias voltages. Spatially resolved I(V)-spectroscopy is performed to identify their energetic origin and behavior. A crucial parameter - the STM tip's work function - is determined experimentally. The voltage dependent potential configuration and band bending situation is derived. Ways to validate the calculations with the experiment are discussed. Differential conductivity maps reveal that the triangular contrasts are only observed with a depletion layer present under the STM tip. The tunnel process leading to the anisotropic contrasts calls for electrons to tunnel through vacuum gap and a finite region in the semiconductor.Comment: 11 pages, 8 figure

Monitoring birds, reptiles and butterflies in the St Katherine Protectorate, Egypt

Fifty-two bird species were recorded during transect and point count surveys of wadis in the St Katherine Protectorate in the mountainous southern region of the Sinai, Egypt. Two species are new to Egypt: Rock Nuthatch (Sitta neumeyer) and Rock Sparrow (Petronia petronia). There were several other notable species: migrants such as Arabian Warbler (Sylvia leucomelaena) and Upcher’s warbler (Hippolais languida); and residents such as Verreaux’s Eagle (Aquila verreauxi), Hume’s Tawny Owl (Strix butleri) and Striated Scops Owl (Otus brucei).Estimates of bird density and descriptions of each wadi are given. Species diversity of wadis within the Ring dyke geological feature bounding the central mountain plateau was not significantly different from wadis outside. Species composition and numbers of individuals varied according to the distribution of water sources, natural trees and Bedouin gardens especially in fruit. These features appear to be particularly important as staging posts for migrants. Numbers ofsome birds increased around tourist areas. Observations of seven species of reptile and ten species of butterfly including endemics arealso presented. Recorded numbers of all groups depended heavily on the time of day

Predictive Value of EGFR-PI3K-AKT-mTOR-Pathway Inhibitor Biomarkers for Head and Neck Squamous Cell Carcinoma:A Systematic Review

BACKGROUND: Understanding molecular pathogenesis of head and neck squamous cell carcinomas (HNSCC) has considerably improved in the last decades. As a result, novel therapeutic strategies have evolved, amongst which are epidermal growth factor receptor (EGFR)-targeted therapies. With the exception of cetuximab, targeted therapies for HNSCC have not yet been introduced into clinical practice. One important aspect of new treatment regimes in clinical practice is presence of robust biomarkers predictive for therapy response.METHODS: We performed a systematic search in PubMed, Embase and the Cochrane library. Articles were included if they investigated a biomarker for targeted therapy in the EGFR-PI3K-AKT-mTOR-pathway.RESULTS: Of 83 included articles, 52 were preclinical and 33 were clinical studies (two studies contained both a preclinical and a clinical part). We classified EGFR pathway inhibitor types and investigated the type of biomarker (biomarker on epigenetic, DNA, mRNA or protein level).CONCLUSION: Several EGFR-PI3K-AKT-mTOR-pathway inhibitor biomarkers have been researched for HNSCC but few of the investigated biomarkers have been adequately confirmed in clinical trials. A more systematic approach is needed to discover proper biomarkers as stratifying patients is essential to prevent unnecessary costs and side effects.</p

Record RF performance of standard 90 nm CMOS technology

We have optimized 3 key RF devices realized in standard logic 90 nm CMOS technology and report a record performance in terms of n-MOS maximum oscillation frequency f/sub max/ (280 GHz), varactor tuning range and varactor and inductor quality factor

Long-Term Outcome of Sustained Endocrine Monotherapy for Elderly Breast Cancer Patients

Background: Among elderly breast cancer patients, endocrine therapy may be chosen as definitive treatment by patients or physicians. This study investigated the efficacy of endocrine monotherapy (ET) in terms of avoidance of invasive local treatment. Methods: Elderly patients (≥70 years) with a diagnosis of estrogen receptor-positive breast cancer who underwent ET between 2008 and 2015 were identified through the Netherlands Cancer Registry. The primary outcome was the cumulative risk of undergoing invasive local treatment (radiotherapy or surgery) for the primary tumor. The secondary outcomes were development of uncontrolled local disease and overall survival (OS). Results: Of the 105 patients (median age, 86 years) enrolled in this study, 91 (78 %) received ET as definitive treatment, whereas 14 received ET as a “bridge to surgery.” For the 91 patients who used ET as intended definitive treatment, the 5-year cumulative risk of undergoing invasive local treatment and experiencing uncontrolled disease were respectively 28 % and 16 %. The 5-year cumulative OS was 42 %. Whereas 11 patients had metastatic or locally progressive breast cancer at the time of death, cardiovascular disease, infectious diseases, and old age or dementia were reported as contributing to the death of 39 patients. Conclusions: For a select group of elderly breast cancer patients who received sustained ET, the risk of undergoing invasive local treatment was surpassed by a twofold higher risk of dying. As an alternative to invasive local treatment, ET can be discussed as a safe and effective option for patients unwilling or unfit to undergo surgery.</p

The RNA Helicase DDX6 Controls Cellular Plasticity by Modulating P-Body Homeostasis

Post-transcriptional mechanisms have the potential to influence complex changes in gene expression, yet their role in cell fate transitions remains largely unexplored. Here, we show that suppression of the RNA helicase DDX6 endows human and mouse primed embryonic stem cells (ESCs) with a differentiation-resistant, “hyper-pluripotent” state, which readily reprograms to a naive state resembling the preimplantation embryo. We further demonstrate that DDX6 plays a key role in adult progenitors where it controls the balance between self-renewal and differentiation in a context-dependent manner. Mechanistically, DDX6 mediates the translational suppression of target mRNAs in P-bodies. Upon loss of DDX6 activity, P-bodies dissolve and release mRNAs encoding fate-instructive transcription and chromatin factors that re-enter the ribosome pool. Increased translation of these targets impacts cell fate by rewiring the enhancer, heterochromatin, and DNA methylation landscapes of undifferentiated cell types. Collectively, our data establish a link between P-body homeostasis, chromatin organization, and stem cell potency