4,364 research outputs found
Carbon nanotube chirality determines properties of encapsulated linear carbon chain
Long linear carbon chains encapsulated inside carbon nanotubes are a very
close realization of carbyne, the truly one-dimensional allotrope of carbon.
Here we study individual pairs of double-walled carbon nanotubes and
encapsulated linear carbon chains by tip-enhanced Raman scattering. We observe
that the radial breathing mode of the inner nanotube correlates with the
frequency of the carbon chain's Raman mode, revealing that the nanotube
chirality determines the vibronic and electronic properties of the encapsulated
carbon chain. We provide the missing link that connects the properties of the
encapsulated long linear carbon chain with the structure of the host nanotube.Comment: keywords: linear carbon chains; carbyne; carbon nanotubes;
tip-enhanced Raman scattering; TERS; Significant changes compared to first
version of the manuscript. Current version includes Supporting Informatio
Ceramic matrix composite turbine engine vane
A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The shell includes a region having a depth-wise coefficient of thermal expansion and a second coefficient of thermal expansion transverse thereto, the depth-wise coefficient of thermal expansion being greater than the second coefficient of thermal expansion
Employing the Houseless as Corporate Social Responsibility
Purpose
Many hospitality organizations see the benefits of engaging in corporate social responsibility (CSR), which can take many forms. This study aims to examine one relatively unique form of CSR: hiring individuals experiencing houselessness. This research aimed to investigate the impact of hiring individuals experiencing houselessness on customers’ behavioral intentions, attitudes toward an organization and perceptions of CSR actions. Design/methodology/approach
Across two experiments, this study investigated the impact of employing individuals experiencing houselessness on customers’ perceptions of the employee and organization using organizational legitimacy theory. Findings
Results demonstrate that employees known to be houseless elicited more positive employee and organizational perceptions from the customers, mediated by CSR perceptions. In addition, the gender of the employees or the quality of the organization did not impact these findings. Practical implications
Hospitality and tourism organizations should consider using available resources or tax benefits to make a deliberate effort to employ those experiencing houselessness. Originality/value
Using organizational legitimacy theory, this study examines CSR perceptions as a potential explanatory mechanism between houselessness and customers’ reactions
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Genome-wide comparison of DNA hydroxymethylation in mouse embryonic stem cells and neural progenitor cells by a new comparative hMeDIP-seq method
The genome-wide distribution patterns of the ‘6th base’ 5-hydroxymethylcytosine (5hmC) in many tissues and cells have recently been revealed by hydroxymethylated DNA immunoprecipitation (hMeDIP) followed by high throughput sequencing or tiling arrays. However, it has been challenging to directly compare different data sets and samples using data generated by this method. Here, we report a new comparative hMeDIP-seq method, which involves barcoding different input DNA samples at the start and then performing hMeDIP-seq for multiple samples in one hMeDIP reaction. This approach extends the barcode technology from simply multiplexing the DNA deep sequencing outcome and provides significant advantages for quantitative control of all experimental steps, from unbiased hMeDIP to deep sequencing data analysis. Using this improved method, we profiled and compared the DNA hydroxymethylomes of mouse ES cells (ESCs) and mouse ESC-derived neural progenitor cells (NPCs). We identified differentially hydroxymethylated regions (DHMRs) between ESCs and NPCs and uncovered an intricate relationship between the alteration of DNA hydroxymethylation and changes in gene expression during neural lineage commitment of ESCs. Presumably, the DHMRs between ESCs and NPCs uncovered by this approach may provide new insight into the function of 5hmC in gene regulation and neural differentiation. Thus, this newly developed comparative hMeDIP-seq method provides a cost-effective and user-friendly strategy for direct genome-wide comparison of DNA hydroxymethylation across multiple samples, lending significant biological, physiological and clinical implications
Tumor-derived alpha-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells
Several tumor-derived factors have been implicated in DC dysfunction in cancer patients. Alpha-fetoprotein (AFP) is an oncofetal antigen that is highly expressed in abnormalities of prenatal development and several epithelial cancers, including hepatocellular carcinoma (HCC). In HCC patients exhibiting high levels of serum AFP, we have observed a lower ratio of myeloid-to-plasmacytoid circulating DC compared to patients with low serum AFP levels and healthy donors, suggesting that AFP alters DC differentiation in vivo. To test the effect of AFP on DC differentiation in vitro, peripheral blood monocytes from healthy donors were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP), and DC phenotype and function was assessed. Although the nAFP and tAFP isoforms only differ at one carbohydrate group, low (physiological) levels of tAFP, but not nAFP, significantly inhibited DC differentiation. tAFP-conditioned DC expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, exhibited limited production of inflammatory mediators, and failed to induce robust T cell proliferative responses. Mechanistic studies revealed that the suppressive activity of tAFP is dependent on the presence of low molecular weight (LMW) species that i) co-purify with tAFP, and ii) are abundant in the LMW fractions of both tumor and non-tumor cell lysates. These data reveal the unique ability of tAFP to serve as a chaperone protein for ubiquitous LMW molecules, which function cooperatively to impair DC differentiation and function. Therefore, novel therapeutic approaches that antagonize the regulatory properties of tAFP will be critical to enhance immunity and improve clinical outcomes
Ceramic matrix composite turbine engine vane
A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The spar has a first chamber essentially along the suction side and a second chamber along the pressure side opposite the first chamber
Antidepressants and Breast and Ovarian Cancer Risk: A Review of the Literature and Researchers\u27 Financial Associations with Industry
Background
Antidepressant (AD) use has been purported to increase the risk of breast and ovarian cancer, although both epidemiological and pre-clinical studies have reported mixed results [1]–[6]. Previous studies in a variety of biomedical fields have found that financial ties to drug companies are associated with favorable study conclusions [7].
Methods and Findings
We searched English-language articles in MEDLINE, PsychINFO, the Science Citations Index and the Cochrane Central Register of Controlled Clinical Trials (through November 2010). A total of 61 articles that assessed the relationship between breast and ovarian cancer and AD use and articles that examined the effect of ADs on cell growth were included. Multi-modal screening techniques were used to investigate researchers\u27 financial ties with industry. A random effects meta-analysis was used to pool the findings from the epidemiological literature. Thirty-three percent (20/61) of the studies reported a positive association between ADs and cancer. Sixty-seven percent (41/61) of the studies reported no association or antiproliferative effect. The pooled odds ratio for the association between AD use and breast/ovarian cancer in the epidemiologic studies was 1.11 (95% CI, 1.03–1.20). Researchers with industry affiliations were significantly less likely than researchers without those ties to conclude that ADs increase the risk of breast or ovarian cancer. (0/15 [0%] vs 20/46 [43.5%] (Fisher\u27s Exact test P = 0.0012).
Conclusions
Both the pre-clinical and clinical data are mixed in terms of showing an association between AD use and breast and ovarian cancer. The possibility that ADs may exhibit a bi-phasic effect, whereby short-term use and/or low dose antidepressants may increase the risk of breast and ovarian cancer, warrants further investigation. Industry affiliations were significantly associated with negative conclusions regarding cancer risk. The findings have implications in light of the 2009 USPSTF guidelines for breast cancer screening and for the informed consent process
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