Primary chordoma of the ethmoid sinus

Primary chordoma of the paranasal sinuses are extremely rare tumours, with only a small number of cases verified and published in the literature. It appears that only five of these cases involved the ethmoid sinuses either as a primary or by local invasion, and of these documented cases only one other has been found to solely involve the ethmoid sinus. We present a case of primary ethmoid sinus chordoma treated by wide local surgical excision and present a review of the literature with regard to prevalence and treatment rationale

How Important Are Wages to the Elderly? Evidence from the New Beneficiary Data System and the Social Security Earnings Test

More than 40 percent of Social Security beneficiaries continue to work after age 65. This research investigates the extent to which these individuals substitute labor across periods in response to anticipated wage changes induced by the Social Security earnings test. While we find that a disproportionate number of individuals choose earnings within a few percentage points of the earnings limit, we find no evidence that these individuals substitute labor supply between

Direct observation of magnetization dynamics generated by nano-contact spin-torque vortex oscillators

Time-resolved scanning Kerr microscopy has been used to directly image the magnetization dynamics of nano-contact (NC) spin-torque vortex oscillators (STVOs) when phase-locked to an injected microwave (RF) current. The Kerr images reveal free layer magnetization dynamics that extend outside the NC footprint, where they cannot be detected electrically, but which are crucial to phase-lock STVOs that share common magnetic layers. For a single NC, dynamics were observed not only when the STVO frequency was fully locked to that of the RF current, but also for a partially locked state characterized by periodic changes in the core trajectory at the RF frequency. For a pair of NCs, images reveal the spatial character of dynamics that electrical measurements show to have enhanced amplitude and reduced linewidth. Insight gained from these images may improve understanding of the conditions required for mutual phase-locking of multiple STVOs, and hence enhanced microwave power emission.Comment: 10 pages, 3 figure

New insight into the causes, consequences, and correction of hematopoietic stem cell aging

Aging of hematopoietic stem cells (HSCs) is characterized by lineage bias, increased clonal expansion, and functional decrease. At the molecular level, aged HSCs typically display metabolic dysregulation, upregulation of inflammatory pathways, and downregulation of DNA repair pathways. Cellular aging of HSCs, driven by cell-intrinsic and cell-extrinsic factors, causes a predisposition to anemia, adaptive immune compromise, myelodys, plasia, and malignancy. Most hematologic diseases are strongly associated with age. But what is the biological foundation for decreased fitness with age? And are there therapeutic windows to resolve age-related hematopoietic decline? These questions were the focus of the International Society for Experimental Hematology (ISEH) New Investigator Committee Fall 2022 Webinar. This review touches on the latest insights from two leading laboratories into inflammatory- and niche-driven stem cell aging and includes speculation on strategies to prevent or correct age-related decline in HSC function

The price of rapid exit in venture capital-backed IPOs

This paper proposes an explanation for two empirical puzzles surrounding initial public offerings (IPOs). Firstly, it is well documented that IPO underpricing increases during “hot issue” periods. Secondly, venture capital (VC) backed IPOs are less underpriced than non-venture capital backed IPOs during normal periods of activity, but the reverse is true during hot issue periods: VC backed IPOs are more underpriced than non-VC backed ones. This paper shows that when IPOs are driven by the initial investor’s desire to exit from an existing investment in order to finance a new venture, both the value of the new venture and the value of the existing firm to be sold in the IPO drive the investor’s choice of price and fraction of shares sold in the IPO. When this is the case, the availability of attractive new ventures increases equilibrium underpricing, which is what we observe during hot issue periods. Moreover, I show that underpricing is affected by the severity of the moral hazard problem between an investor and the firm’s manager. In the presence of a moral hazard problem the degree of equilibrium underpricing is more sensitive to changes in the value of the new venture. This can explain why venture capitalists, who often finance firms with more severe moral hazard problems, underprice IPOs less in normal periods, but underprice more strongly during hot issue periods. Further empirical implications relating the fraction of shares sold and the degree of underpricing are presented

Initiation context modulates autoregulation of eukaryotic translation initiation factor 1 (eIF1)

The central feature of standard eukaryotic translation initiation is small ribosome subunit loading at the 5′ cap followed by its 5′ to 3′ scanning for a start codon. The preferred start is an AUG codon in an optimal context. Elaborate cellular machinery exists to ensure the fidelity of start codon selection. Eukaryotic initiation factor 1 (eIF1) plays a central role in this process. Here we show that the translation of eIF1 homologs in eukaryotes from diverse taxa involves initiation from an AUG codon in a poor context. Using human eIF1 as a model, we show that this poor context is necessary for an autoregulatory negative feedback loop in which a high level of eIF1 inhibits its own translation, establishing that variability in the stringency of start codon selection is used for gene regulation in eukaryotes. We show that the stringency of start codon selection (preferential utilization of optimal start sites) is increased to a surprising degree by overexpressing eIF1. The capacity for the cellular level of eIF1 to impact initiation through the variable stringency of initiation codon selection likely has significant consequences for the proteome in eukaryotes