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141.
Reproductive aging is characterized by a decline in ovarian function and in oocytes’ quantity and quality. Pigment epithelium-derived factor (PEDF), a pivotal player in ovarian angiogenic and oxidative balance, was evaluated for its involvement in reproductive aging. Our work examines the initial stage of reproductive aging in women and mice, and the involvement of PEDF in the process. Granulosa cells from reproductively-aged (RA) women and mice (36–44 years old and 9–10 months old, respectively) indicated an increase in the level of PEDF mRNA (qPCR), with yet unchanged levels of AMH and FSHR mRNAs. However, the PEDF protein level in individual women showed an intra-cellular decrease (ELISA), along with a decrease in the corresponding follicular fluid, which reflects the secreted fraction of the protein. The in vitro maturation (IVM) rate in the oocytes of RA mice was lower compared with the oocytes of young mice, demonstrated by a reduced polar body extrusion (PBE) rate. The supplementation of PEDF improved the hampered PBE rate, manifested by a higher number of energetically-competent oocytes (ATP concentration and mtDNA copy number of individual oocytes). Our findings propose PEDF as an early marker of reproductive aging, and a possible therapeutic in vitro agent that could enhance the number of good-quality oocytes in older IVF patients.  相似文献   
142.
The controlled nanoscale patterning of 2D materials is a promising approach for engineering the optoelectronic, thermal, and mechanical properties of these materials to achieve novel functionalities and devices. Herein, high‐resolution patterning of hexagonal boron nitride (h‐BN) is demonstrated via both helium and neon ion beams and an optimal dosage range for both ions that serve as a baseline for insulating 2D materials is identified. Through this nanofabrication approach, a grating with a 35 nm pitch, individual structure sizes down to 20 nm, and additional nanostructures created by patterning crystal step edges are demonstrated. Raman spectroscopy is used to study the defects induced by the ion beam patterning and is correlated to scanning probe microscopy. Photothermal and scanning near‐field optical microscopy measure the resulting near‐field absorption and scattering of the nanostructures. These measurements reveal a large photothermal expansion of nanostructured h‐BN that is dependent on the height to width aspect ratio of the nanostructures. This effect is attributed to the large anisotropy of the thermal expansion coefficients of h‐BN and the nanostructuring implemented. The photothermal expansion should be present in other van der Waals materials with large anisotropy and can lead to applications such as nanomechanical switches driven by light.  相似文献   
143.
Entangled photon pairs are a fundamental component for testing the foundations of quantum mechanics, and for modern quantum technologies such as teleportation a...  相似文献   
144.

Recommender systems provide personalized information access to users of Internet services from social networks to e-commerce to media and entertainment. As is appropriate for research in a field with a focus on personalization, academic studies of recommender systems have largely concentrated on optimizing for user experience when designing, implementing and evaluating their algorithms and systems. However, this concentration on the user has meant that the field has lacked a systematic exploration of other aspects of recommender system outcomes. A user-centric approach limits the ability to incorporate system objectives, such as fairness, balance, and profitability, and obscures concerns that might come from other stakeholders, such as the providers or sellers of items being recommended. Multistakeholder recommendation has emerged as a unifying framework for describing and understanding recommendation settings where the end user is not the sole focus. This article outlines the multistakeholder perspective on recommendation, highlighting example research areas and discussing important issues, open questions, and prospective research directions.

  相似文献   
145.
This paper is a summary of already published papers on the bioactive bone cement (BA cement) which consists of CaO-SiO2-P2O5-MgO-CaF2 (AW glass-ceramic) powder and bisphenol-a-glycidyl methacrylate (Bis-GMA) resin. Two types of BA cement, dough and injection type, were prepared by changing their chemical compositions slightly. They harden in a few minutes exhibiting much lower curing temperature than PMMA cement. They have significantly higher compressive, bending, and tensile strengths than PMMA cement and have a character of bonding directly with bone in 4-8 weeks in vivo. Intercalary prosthetic replacement of the femur and total prosthetic replacement of the hip were performed in dogs using either PMMA cement or BA cement. Mechanical tests demonstrated that fixation strengths of these prostheses with BA cement increased with time and were significantly greater than those with PMMA cement tested at any time. Results of histological examinations showed direct bonding between BA cement and bone, and that the bone trabeculae around BA cement mantle grew with time, while with PMMA cement an intervening soft tissue layer was always observed at the cement-bone interface. BA cement was used in a few aged patients to install a hip prosthesis either in cases of revision or femoral neck fracture. The longest follow-up period of the patient is 4 yrs. The patients have been doing well with no adverse effect of the cement to date.  相似文献   
146.
An on-board sample cleaver has been developed in order to cleave small and hard-to-cleave samples. To acquire good cleaves from rigid samples the alignment of the cleaving blade with respect to the internal crystallographic planes is crucial. To have the opportunity to mount the sample and align it to the blade ex situ has many advantages. The design presented has allowed us to cleave very tiny and rigid samples, e.g., the high-temperature superconductor La((2-x))Sr(x)CuO(4). Further, in this design the sample and the cleaver will have the same temperature, allowing us to cleave and keep the sample at low temperature. This is a big advantage over prior cleaver systems. As a result, better surfaces and alignments can be realized, which considerably simplifies and improves the experiments.  相似文献   
147.
The effects of methanol and ethanol vapor‐induced crystallization on vapor and gas permeabilities and on the structure of poly(lactic acid) (PLA) films were systematically investigated. At high temperature conditions, the vapor permeability of PLA films decreased with increasing exposure time. The PLA films that were exposed to alcohol vapor became slightly cloudy, and no changes in chemical structure were observed. Alcohol vapor‐induced crystallization formed α‐crystal structure. The vapor permeability decreased with increasing crystallinity. However, nitrogen permeability slightly increased after vapor‐induced crystallization. The dependence of crystallinity on vapor and gas permeabilities was different from each penetrant. Total crystalline structures, including continuous crystal structures, remaining amorphous regions, and their interface depend on vapor and gas permeabilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40140.  相似文献   
148.
Knowledge Discovery in Databases (KDD) focuses on the computerized exploration of large amounts of data and on the discovery of interesting patterns within them. While most work on KDD has been concerned with structured databases, there has been little work on handling the huge amount of information that is available only in unstructured textual form. This paper describes the KDT system for Knowledge Discovery in Text, in which documents are labeled by keywords, and knowledge discovery is performed by analyzing the co-occurrence frequencies of the various keywords labeling the documents. We show how this keyword-frequency approach supports a range of KDD operations, providing a suitable foundation for knowledge discovery and exploration for collections of unstructured text.  相似文献   
149.
Inconsistency in flavour is one of the major challenges to the Australian papaya industry. However, objectively measurable standards of the compound profiles that provide preferable taste and aroma, together with consumer acceptability, have not been set. In this study, three red-flesh papayas (i.e., ‘RB1’, ‘RB4’, and ‘Skybury’) and two yellow-flesh papayas (i.e., ‘1B’ and ‘H13’) were presented to a trained sensory panel and a consumer panel to assess sensory profiles and liking. The papaya samples were also examined for sugar components, total soluble solids, and 14 selected volatile compounds. Additionally, the expression patterns of 10 genes related to sweetness and volatile metabolism were assessed. In general, red papaya varieties had higher sugar content and tasted sweeter than yellow varieties, while yellow varieties had higher concentrations of citrus floral aroma volatiles and higher aroma intensity. Higher concentrations of glucose, linalool oxide, and terpinolene were significantly associated with decreased consumer liking. Significant differences were observed in the expression profiles of all the genes assessed among the selected papaya varieties. Of these, cpGPT2 and cpBGLU31 were positively correlated to glucose production and were expressed significantly higher in ‘1B’ than in ‘RB1’ or ‘Skybury’. These findings will assist in the strategic selective breeding for papaya to better match consumer and, hence, market demand.  相似文献   
150.
Abstract

We analyse the diffusion of photons in a two-layer turbid medium, paying specific attention to parameters suggested by the use of lasers for diagnostic purposes in a medical setting. The data produced by such experiments consists of an intensity profile measured on the surface of the medium, which is measured either as a function of time at a fixed distance from the input laser beam, or else as a function of distance keeping the measurement time fixed. In both cases we demonstrate that the presence of a second layer can be detected provided that physical properties of the two layers differ by a sufficient amount, and also show up in calculated values of such parameters as the mean travel time of a photon to the surface of the medium, and the distribution of the maximum depth reached by an arbitrary photon.  相似文献   
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