84 research outputs found
Low-density nanoporous iron foams synthesized by sol-gel autocombustion
Nanoporous iron metal foams were synthesized by an improved sol-gel autocombustion method in this report. It has been confirmed to be pure phase iron by X-ray diffraction measurements. The nanoporous characteristics were illustrated through scanning electron microscope and transmission electron microscope images. Very low density and quite large saturation magnetization has been performed in the synthesized samples
In Vitro Studies of Cells Grown on the Superconductor PrOxFeAs
The recent discovery of arsenic-based high temperature superconductors has
reignited interest in the study of superconductor : biological interfaces.
However, the new superconductor materials involve the chemistry of arsenic,
their toxicity remain unclear [ Nature, 2008, 452(24):922]. In this study the
possible adverse effects of this new family of superconductors on cells have
been examined. Cell culture studies in conjunction with microscopy and
viability assays were employed to examine the influence of arsenic-based
superconductor PrOxFeAs (x=0.75) material in vitro. Imaging data revealed that
cells were well adhered and spread on the surface of the superconductor.
Furthermore, cytotoxicity studies showed that cells were unaffected during the
time-course of the experiments, providing support for the biocompatibility
aspects of PrOxFeAs-based superconductor material.Comment: Are the FeAs based superconductors toxic
GABP transcription factor is required for development of chronic myelogenous leukemia via its control of PRKD2
Hematopoietic stem cells (HSCs) are the source of all blood lineages, and HSCs must balance quiescence, self-renewal, and differentiation to meet lifelong needs for blood cell development. Transformation of HSCs by the breakpoint cluster region-ABL tyrosine kinase (BCR-ABL) oncogene causes chronic myelogenous leukemia (CML). The E-twenty six (ets) transcription factor GA binding protein (GABP) is a tetrameric transcription factor complex that contains GABPalpha and GABPbeta proteins. Deletion in bone marrow of Gabpa, the gene that encodes the DNA-binding component, caused cell cycle arrest in HSCs and profound loss of hematopoietic progenitor cells. Loss of Gabpalpha prevented development of CML, although mice continued to generate BCR-ABL-expressing Gabpalpha-null cells for months that were serially transplantable and contributed to all lineages in secondary recipients. A bioinformatic screen identified the serine-threonine kinase protein kinase D2 (PRKD2) as a potential effector of GABP in HSCs. Prkd2 expression was markedly reduced in Gabpalpha-null HSCs and progenitor cells. Reduced expression of PRKD2 or pharmacologic inhibition decreased cell cycling, and PRKD2 rescued growth of Gabpalpha-null BCR-ABL-expressing cells. Thus, GABP is required for HSC cell cycle entry and CML development through its control of PRKD2. This offers a potential therapeutic target in leukemia
Mildly relativistic motion in the radio-quiet quasar PG 1351+640
Measuring the proper motion of the emission component in radio-quiet quasars (RQQs) could help to distinguish between the origins of the radio emission and to understand whether the jet production mechanism is the same in radio-loud quasars and RQQs. PG 1351+640 is one of the few RQQs suitable for proper motion studies: it has two compact components on milli-arcsec scales, a flat-spectrum core and a steep-spectrum jet; both components are ≳2 mJy at 5 GHz and are well suited for Very Long Baseline Array (VLBA) observations. We compare recent VLBA observations with that made seventeen years ago and find no significant change in the core-jet separation between 2005 and 2015 (a proper motion of 0.003 mas yr-1). However, the core-jet separation increased significantly between 2015 and 2022, inferring a jet proper motion velocity of 0.063 mas yr-1, which corresponds to an apparent transverse velocity of. The result suggests that the jet of the RQQ PG 1351+640 is mildly relativistic and oriented at a relatively small viewing angle
TaskMatrix.AI: Completing Tasks by Connecting Foundation Models with Millions of APIs
Artificial Intelligence (AI) has made incredible progress recently. On the
one hand, advanced foundation models like ChatGPT can offer powerful
conversation, in-context learning and code generation abilities on a broad
range of open-domain tasks. They can also generate high-level solution outlines
for domain-specific tasks based on the common sense knowledge they have
acquired. However, they still face difficulties with some specialized tasks
because they lack enough domain-specific data during pre-training or they often
have errors in their neural network computations on those tasks that need
accurate executions. On the other hand, there are also many existing models and
systems (symbolic-based or neural-based) that can do some domain-specific tasks
very well. However, due to the different implementation or working mechanisms,
they are not easily accessible or compatible with foundation models. Therefore,
there is a clear and pressing need for a mechanism that can leverage foundation
models to propose task solution outlines and then automatically match some of
the sub-tasks in the outlines to the off-the-shelf models and systems with
special functionalities to complete them. Inspired by this, we introduce
TaskMatrix.AI as a new AI ecosystem that connects foundation models with
millions of APIs for task completion. Unlike most previous work that aimed to
improve a single AI model, TaskMatrix.AI focuses more on using existing
foundation models (as a brain-like central system) and APIs of other AI models
and systems (as sub-task solvers) to achieve diversified tasks in both digital
and physical domains. As a position paper, we will present our vision of how to
build such an ecosystem, explain each key component, and use study cases to
illustrate both the feasibility of this vision and the main challenges we need
to address next
Comprehensive genomic analysis of Oesophageal Squamous Cell Carcinoma reveals clinical relevance
Abstract Oesophageal carcinoma is the fourth leading cause of cancer-related death in China, and more than 90% of these tumours are oesophageal squamous cell carcinoma (ESCC). Although several ESCC genomic sequencing studies have identified mutated somatic genes, the number of samples in each study was relatively small, and the molecular basis of ESCC has not been fully elucidated. Here, we performed an integrated analysis of 490 tumours by combining the genomic data from 7 previous ESCC projects. We identified 18 significantly mutated genes (SMGs). PTEN, DCDC1 and CUL3 were first reported as SMGs in ESCC. Notably, the AJUBA mutations and mutational signature4 were significantly correlated with a poorer survival in patients with ESCC. Hierarchical clustering analysis of the copy number alteration (CNA) of cancer gene census (CGC) genes in ESCC patients revealed three subtypes, and subtype3 exhibited more CNAs and marked for worse prognosis compared with subtype2. Moreover, database annotation suggested that two significantly differential CNA genes (PIK3CA and FBXW7) between subtype3 and subtype2 may serve as therapeutic drug targets. This study has extended our knowledge of the genetic basis of ESCC and shed some light into the clinical relevance, which would help improve the therapy and prognosis of ESCC patients
How Overconfidence Influences the Herding Behavior in a Modified Information Cascade Game
Humans are social animals. In everyday life, people rarely make important decisions solely based on their personal opinions. Most human decisions are made in a social context. People seek help from relatives, peers, experts, and more to make decisions. To mimic this fact, Anderson and Holt (1997) devised an experiment design, the information cascade game, in which players guess the actual state of the world based on their private signals and others’ prior choices. On another side of the picture, Michailova (2010) defines overconfidence as the act of a person overestimating his or her skill, knowledge, and precision of information. According to Camerer and Lovallo (1999), subjects exhibit overconfidence when placing bets on their relative performance. In this experiment, the baseline treatment of the information cascade game is modified so that subjects’ overconfidence actively participates in subjects’ guesses about the actual state of the world. Under this modified experiment design, subjects’ confidence level is negatively correlated with the herding frequency
Properties and Structure of Fiber-Reinforced Injection-Molded Part
Fiber-reinforced plastics exhibit many merits and injection molding is one of the most common method for the production of plastics. Therefore, injection-molded fiber-reinforced plastic products have been widely used and their properties and structure were studied in the present work. The influences of fiber type, fiber content, and processing on the internal morphological structure of the injection-molded composite materials were investigated. Moreover, the change of performance of plastic products was analyzed
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