Beta Stability Research Articles

IGF2BP2-modified circular RNA circCHD7 promotes endometrial cancer progression via stabilizing PDGFRB and activating JAK/STAT signaling pathway

Circular RNAs (circRNAs) represent a class of covalently closed, single-stranded RNAs and have been linked to cancer progression. N6-methyladenosine (m6A) methylation is a ubiquitous RNA modification in cancer cells. Increasing evidence suggests that m6A can mediate the effects of circRNAs in cancer biology. In contrast, the post-transcriptional systems of m6A and circRNA in the progression of endometrial cancer (EC) remain obscure. The current study identified a novel circRNA with m6A modification, hsa_circ_0084582 (circCHD7), which was upregulated in EC tissues. Functionally, circCHD7 was found to promote the proliferation of EC cells. Mechanistically, circCHD7 interacted with insulin-like growth factor 2 mRNA-binding protein (IGF2BP2) to amplify its enrichment. Moreover, circCHD7 increased the mRNA stability of platelet-derived growth factor receptor beta (PDGFRB) in an m6A-dependent manner, thereby enhancing its expression. In addition, the circCHD7/IGF2BP2/PDGFRB axis activated the JAK/STAT signaling pathway and promoted EC cell proliferation. In conclusion, these findings provide new insights into the regulation of circRNA-mediated m6A modification, and the new “circCHD7-PDGFRB” model of regulation offers new perspectives on circCHD7 as a potential target for EC therapy.

Effect of Molybdenum on the Mechanical and Corrosion Properties of Ti-xMo-2Fe Beta Alloys

Titanium alloys are currently used in offshore industries. The titanium alloys used in offshore plants need to have excellent corrosion resistance and mechanical properties because offshore plants are exposed to harsh corrosive environments. At this time, the Ti-6Al-4V ELI alloy is mainly used in offshore plants because it has excellent mechanical properties and corrosion resistance. However, Ti-6Al-4V ELI alloy has the disadvantage of poor formability. To improve this, studies on metastable beta-Titanium alloys with a BCC structure are being actively conducted. In this study, a metastable beta-titanium alloy was fabricated using Mo, which is inexpensive and improves corrosion resistance, and Fe, which improves strength, among the titanium beta stabilizer elements. After the Ti-6Al-4V ELI and Ti-xMo-2Fe alloys solution treatments, electrochemical corrosion experiments were conducted to analyze corrosion characteristics, and mechanical properties were also analyzed through compression tests at room temperature and Vickers hardness measurement. Corrosion properties and the mechanical properties of Ti-xMo-2Fe alloy were considered in connect experiments such as microstructure analysis and hardness measurement. It was confirmed that the corrosion resistance of the Ti-xMo-2Fe alloy was better than that of the Ti-6Al-4V ELI alloy, and it was confirmed that the compressive strength and elongation rate of Ti-xMo-2Fe with its BCC structure get higher than Ti-6Al-4V ELI alloy.

Disrupted hypothalamic transcriptomics and proteomics in a mouse model of type 2 diabetes exposed to recurrent hypoglycaemia

Aims/hypothesisRepeated exposures to insulin-induced hypoglycaemia in people with diabetes progressively impairs the counterregulatory response (CRR) that restores normoglycaemia. This defect is characterised by reduced secretion of glucagon and other counterregulatory hormones. Evidence indicates that glucose-responsive neurons located in the hypothalamus orchestrate the CRR. Here, we aimed to identify the changes in hypothalamic gene and protein expression that underlie impaired CRR in a mouse model of defective CRR.MethodsHigh-fat-diet fed and low-dose streptozocin-treated C57BL/6N mice were exposed to one (acute hypoglycaemia [AH]) or multiple (recurrent hypoglycaemia [RH]) insulin-induced hypoglycaemic episodes and plasma glucagon levels were measured. Single-nuclei RNA-seq (snRNA-seq) data were obtained from the hypothalamus and cortex of mice exposed to AH and RH. Proteomic data were obtained from hypothalamic synaptosomal fractions.ResultsThe final insulin injection resulted in similar plasma glucose levels in the RH group and AH groups, but glucagon secretion was significantly lower in the RH group (AH: 94.5±9.2 ng/l [n=33]; RH: 59.0±4.8 ng/l [n=37]; p<0.001). Analysis of snRNA-seq data revealed similar proportions of hypothalamic cell subpopulations in the AH- and RH-exposed mice. Changes in transcriptional profiles were found in all cell types analysed. In neurons from RH-exposed mice, we observed a significant decrease in expression of Avp, Pmch and Pcsk1n, and the most overexpressed gene was Kcnq1ot1, as compared with AH-exposed mice. Gene ontology analysis of differentially expressed genes (DEGs) indicated a coordinated decrease in many oxidative phosphorylation genes and reduced expression of vacuolar H+- and Na+/K+-ATPases; these observations were in large part confirmed in the proteomic analysis of synaptosomal fractions. Compared with AH-exposed mice, oligodendrocytes from RH-exposed mice had major changes in gene expression that suggested reduced myelin formation. In astrocytes from RH-exposed mice, DEGs indicated reduced capacity for neurotransmitters scavenging in tripartite synapses as compared with astrocytes from AH-exposed mice. In addition, in neurons and astrocytes, multiple changes in gene expression suggested increased amyloid beta (Aβ) production and stability. The snRNA-seq analysis of the cortex showed that the adaptation to RH involved different biological processes from those seen in the hypothalamus.Conclusions/interpretationThe present study provides a model of defective counterregulation in a mouse model of type 2 diabetes. It shows that repeated hypoglycaemic episodes induce multiple defects affecting all hypothalamic cell types and their interactions, indicative of impaired neuronal network signalling and dysegulated hypoglycaemia sensing, and displaying features of neurodegenerative diseases. It also shows that repeated hypoglycaemia leads to specific molecular adaptation in the hypothalamus when compared with the cortex.Data availabilityThe transcriptomic dataset is available via the GEO (http://www.ncbi.nlm.nih.gov/geo/), using the accession no. GSE226277. The proteomic dataset is available via the ProteomeXchange data repository (http://www.proteomexchange.org), using the accession no. PXD040183.Graphical

Deubiquitinase USP1 enhances CCAAT/enhancer-binding protein beta (C/EBPβ) stability and accelerates adipogenesis and lipid accumulation

Dysregulation of the ubiquitin-proteasome system has been implicated in the pathogenesis of several metabolic disorders, including obesity, diabetes, and non-alcoholic fatty liver disease; however, the mechanisms controlling pathogenic metabolic disorders remain unclear. Transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) regulates adipogenic genes. The study showed that the expression level of C/EBPβ is post-translationally regulated by the deubiquitinase ubiquitin-specific protease 1 (USP1) and that USP1 expression is remarkably upregulated during adipocyte differentiation and in the adipose tissue of mice fed a high-fat diet (HFD). We found that USP1 directly interacts with C/EBPβ. Knock-down of USP1 decreased C/EBPβ protein stability and increased its ubiquitination. Overexpression of USP1 regulates its protein stability and ubiquitination, whereas catalytic mutant of USP1 had no effect on them. It suggests that USP1 directly deubiquitinases C/EBPβ and increases the protein expression, leading to adipogenesis and lipid accumulation. Notably, the USP1-specific inhibitor ML323—originally developed to sensitize cancer cells to DNA-damaging agents—decreased adipocyte differentiation and lipid accumulation in 3T3-L1 cells without cytotoxicity. Oral gavage of ML323 was administered to HFD-fed mice, which showed weight loss and improvement in insulin and glucose sensitivity. Both fat mass and adipocyte size in white adipose tissues were significantly reduced by ML323 treatment, which also reduced the expression of genes involved in adipogenesis and inflammatory responses. ML323 also reduced lipid accumulation, hepatic triglycerides, free fatty acids, and macrophage infiltration in the livers of HFD-fed mice. Taken together, we suggest that USP1 plays an important role in adipogenesis by regulating C/EBPβ ubiquitination, and USP1-specific inhibitor ML323 is a potential treatment option and further study by ML323 is needed for clinical application for metabolic disorders.

Improved interfacial strength of Ti/Ti ultrasonic welds by introducing α/β/α heterogeneous bonding interface

We investigated ultrasonic welding (USW) of pure α-Ti sheets, which exhibited an insufficient weldability due to the extensive formation of cracks caused by sliding friction during the USW. To overcome this issue, an α/β/α heterogeneous interfacial microstructure was designed by introducing a thin Fe interlayer, a beta stabilizer, between α-Ti sheets. The diffusion of Fe interlayers triggered the formation of a continuous β-Ti thin layer (⁓1–2 μm) without Fe–Ti intermetallics near the bonding interface after USW. The continuous thin β-Ti layer exhibited a significant improvement in the joining of the brittle α-Ti, where the bonding strength was increased from 350 to 1700 N. This study provides a potential approach to design an interfacial microstructure that promotes the formation of a deformable phase, overcoming the inherent brittleness of hexagonal close-packed metals and enabling production of strong joints.

A Study on Compressive Behaviour of Thermal Cycled Titanium Alloy

Abstract: Now a day, the titanium was recognized for its strategic importance as a unique lightweight, high strength alloyed structurally efficient metal for critical, high-performance aircraft, such as jet engine and airframe components. Titanium -6Al4v alloy is an alpha + beta alloy, which generally contains alpha and beta stabilizers and is heat treatable to various degrees. Over 70% of all Titanium alloy grades melted on a sub grade of Ti-6A1-4v which is used in aerospace, air frame and engine components. , Titanium alloy (Ti-6Al-4v) is heat treated for two different methods in order to get optimum combination of ductility, machinability and structural stability by annealing and to increase the strength by solution treating. Compression test was carried out at room temperature using a Universal testing machine. The flow behavior of different heat treatment and thermal cycled specimens were studied. The comparative study of the flow behavior of titanium alloy was made.

Exotic decay modes of uranium isotopes

We investigate the emission of alpha particles and various clusters from uranium isotopes using the Effective Liquid Drop Model. The study has been carried out for the isotopes ranging between the p-drip-line and beta stability line. The half-lives calculated are in good agreement with the Universal Decay law, the scaling law of Horoi et al. and also with the available experimental values. We have listed the half-lives of all probable decay modes of uranium isotopes. The uncertainties in Q-value and half-lives are also presented. It is also observed that the probability of cluster emission decreases with the increase of neutron number of parent nuclei. The linear nature Geiger-Nuttal plot has been reproduced for the prominent decay modes. The study also affirms the inevitable role of neutron magicity in cluster radioactivity. We have also analyzed the branching ratios to identify the most prominent decay modes of uranium isotopes.

Modeling the Time Variation in Factor Exposures

Abstract This paper offers new evidence on the dynamic behavior of multifactor models. Specifically, we investigate the significance and temporal stability of conditional factor betas in the context of multifactor asset pricing models. Using a Kalman filter approach, we find that conditional factor betas are dynamic and their statistical significance varies over time. Furthermore, the inclusion of more factors improves that statistical significance and time stability of the market factor. Overall, our empirical results support the view that multifactors may not be independent risk factors but help to better identify the market factor. JEL classification numbers: G11; G12. Keywords: Asset Pricing, Risk Factors.

Stability and Activity of Interferon Beta to Treat Idiopathic Pulmonary Fibrosis with Different Nebulizer Technologies.

Background: Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by lung scarring, which results in breathing difficulty. Currently, patients with IPF exhibit a poor survival rate and have access to very limited therapeutic options. Interferon beta (IFN-β) has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsing forms of multiple sclerosis, and it has also been shown to exhibit therapeutic potential in IPF. However, clinical use of IFN-β did not lead to improved overall survival in IPF patients in existing studies. One possibility is the limited efficiency of IFN-β delivery through intravenous or subcutaneous injection. Materials and Methods: The aerosol particle size distribution was determined with a laser diffraction particle size analyzer to characterize the droplet size and fine particle fraction generated by three types of nebulizers: jet, ultrasonic, and mesh. A breathing simulator was used to assess the delivery efficiency of IFN-β, and the temperature in the medication reservoirs was monitored with a thermocouple during nebulization. To further evaluate the antifibrotic activity of IFN-β pre- and postnebulization, bleomycin (BLM)- or transforming growth factor-beta (TGF-β)-treated human lung fibroblast (HLF) cells were used. Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Transwell migration assay and Q-PCR analysis were used to evaluate cell migration and the myofibroblast differentiation ability, respectively. IFN-β protein samples were prepared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample loading buffer, and the expression of IFN-β was assessed by western blotting. Results: Among the current drug delivery systems, aerosolized medication has shown increased efficacy of drug delivery for treating respiratory diseases when compared with parenteral drugs. It was found that neither the structural integrity nor the biological function of nebulized IFN-β was compromised by the nebulization process of the mesh nebulizer. In addition, in BLM dose-response or TGF-β-induced lung fibroblast proliferation assays, these effects could be reversed by both parenteral and inhaled IFN-β nebulized with the mesh nebulizer. Nebulized IFN-β with the mesh nebulizer also significantly inhibited the migration and myofibroblast differentiation ability of TGF-β-treated HLF cells. Conclusions: The investigations revealed the potential efficacy of IFN-β in the treatment of IPF with the mesh nebulizer, demonstrating the higher efficiency of IFN-β delivered through the mesh nebulizer.

Fission yield model for astrophysical use based on the four-dimensional Langevin model

Nuclear fission is expected to play an essential role in the r-process nucleosynthesis via the fission recycling process. However, the impact of the fission recycling process on the r-process is still unclear due to the ambiguity of the fission yields for nuclei far from the beta-stability line and superheavy nuclei. Our four-dimensional Langevin model can reproduce experimental nuclear fission properties, such as fission fragment mass distributions and total kinetic energies in a systematic manner including their sudden changes due to shell structure. Then we developed a phenomenological yield model for nuclei Z=92 to 122, ranging from neutron deficient to very neutron-rich ones, by fitting the fission fragment mass yield obtained by the Langevin model with five Gaussians. We use the charge distributions for each isobar based on a parametrization which we have evaluated based on thousands of experimental data for actinides, to obtain the fission yields in the form of (Z, N) distributions. What is unique here is the sudden change of the mass distribution from a 2-peak to 1-peak structure for the region of 256Fm, and the appearance of a 5-peak structure for superheavy nuclei predicted by the 4D Langevin calculation.

Microstructural characterization of additively manufactured Ti-6Al-4V with the addition of β-stabilizer, niobium

This study investigated the influence of beta stabilizer niobium on the microstructure and hardness of Ti-6Al-4V. The relationship between increased the concentration of alloying elements into Ti-6Al-4V is generally associated with an increase in hardness due to solid solution strengthening. The research involved the fabrication of a series of laser engineering net shaping (LENS™) Ti-6Al-4V alloys with varying concentrations of niobium (13%, 20%, and 28%) to determine whether increasing the Nb content has an influence on the concentration of Nb dissolved into Ti-6Al-4V. The microstructures of these alloys were analysed the hardness examined. the results revealed that the solid solution strengthening did not lead to a proportional increase in hardness as expected. Further microstructural examination showed that the alloy with 13% Nb exhibited a distinct microstructure with a higher concentration of un-melted Nb particles, whereas the alloy with 28% Nb had a higher dissolution of Nb into the Ti-6Al-4V. The least percentage of Nb dissolved into the Ti-6Al-4V compared to the addition of 28% Nb. Increased Nb content resulted in a higher percentage of Nb dissolved in Ti-6Al-4V but the lower hardness value. The undissolved Nb did not contribute solid solution strengthening but rather the presence of defects, and features of microstructure are responsible for hindering the ease of plastic deformation.

Recent progress in two-proton radioactivity

During the last few decades, rare isotope beam facilities have provided unique data for studying the properties of nuclides located far from the beta-stability line. Such nuclei are often accompanied by exotic structures and radioactive modes, which represent the forefront of nuclear research. Among them, two-proton (2p) radioactivity is a rare decay mode found in a few highly proton-rich isotopes. The 2p decay lifetimes and properties of emitted protons hold invaluable information regarding the nuclear structures in the presence of a low-lying proton continuum; as such, they have attracted considerable research attention. In this review, we present some of the recent experimental and theoretical progress regarding the 2p decay, including technical innovations for measuring nucleon–nucleon correlations and developments in the models that connect their structural aspects with their decay properties. This impressive progress should play a significant role in elucidating the mechanism of these exotic decays, probing the corresponding components inside nuclei, and providing deep insights into the open quantum nature of dripline systems.

A positive feedback loop between LINC01605 and NF-κB pathway promotes tumor growth in nasopharyngeal carcinoma

ABSTRACT zong non-coding RNAs (lncRNAs) have been identified as crucial effector in modulating the progression of assorted malignancies. In our study, the main aim was to unveil the role and the underlying regulatory mechanism of long intergenic non-protein coding RNA 1605 (LINC01605) in nasopharyngeal carcinoma (NPC). RT-qPCR analysis results suggested that LINC01605 was upregulated in NPC cells. According to the results of function experiments, LINC01605 promoted NPC cell proliferation and impeded cell apoptosis. The oncogenic role of LINC01605 in NPC was further validated by animal experiments. Additionally, we verified that LINC01605 regulated Ikbkb expression to promote the nuclear translocation of p65 and thereby activated the NF-κB pathway in NPC cells. Mechanism experiments further suggested that LINC01605 could regulate Ikbkb expression via sponging miR-942-5p. Moreover, LINC01605 recruited IGF2BP2 to stabilize ubiquitin-specific protease 3 (USP3) mRNA and thereby enhanced the stability of IkB subunit beta (IKKβ) protein. In addition, p65 acted as a transcription activator to upregulate LINC01605 in NPC cells. In conclusion, this study demonstrated a positive feedback loop between LINC01605 and the NF-κB signalling pathway that promoted NPC cell growth, thus providing new insights to better understand NPC.

LncRNA Neat1 regulates neuronal dysfunction post-sepsis via stabilization of hemoglobin subunit beta

Sepsis-associated encephalopathy (SAE) is characterized by acute and diffuse brain dysfunction and correlates with long-term cognitive impairments with no targeted therapy. We used a mouse model of sepsis-related cognitive impairment to examine the role of lncRNA nuclear enriched abundant transcript 1 (Neat1) in SAE. We observed that Neat1 expression was increased in neuronal cells from septic mice and that it directly interacts with hemoglobin subunit beta (Hbb), preventing its degradation. The Neat1/Hbb axis suppressed postsynaptic density protein 95 (PSD-95) levels and decreased dendritic spine density. Neat1 knockout mice exhibited decreased Hbb levels, which resulted in increased PSD-95 levels, increased neuronal dendritic spine density, and decreased anxiety and memory impairment. Neat1 silencing via the antisense oligonucleotide GapmeR ameliorated anxiety-like behavior and cognitive impairment post-sepsis. In conclusion, we uncovered a previously unknown mechanism of the Neat1/Hbb axis in regulating neuronal dysfunction, which may lead to a novel treatment strategy for SAE.

Electrochemical Characterization of Titanium Alloy Anodized

The titanium has excellent electrochemical properties due to the formation of TiO2 on the surface. The capacity of generating a protective layer will depend on the titanium alloy used. Titanium alloys (Ti CP2, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-4V, and Ti Beta-C) were anodized in H2SO4 and H3PO4 at 1M concentration employing a current density of 0.025A/cm2. Electrochemical characterization was made by potentiodynamic polarization (ASTM G61). Alloys anodized on H3PO4 presented an electrochemical behavior related to a more homogenous layer. Alloys with more beta stabilizers showed higher corrosion resistance than the anodized alpha and near alpha alloys.

Effect of Nb on β → α ″ Martensitic Phase Transformation and Characterization of New Biomedical Ti-xNb-3Fe-9Zr Alloys.

A new generation of Ti-xNb-3Fe-9Zr (x = 15, 20, 25, 30, 35 wt %) alloys have been designed using various theoretical approaches including DV-xα cluster, molybdenum equivalency, and electron to atom ratio. Afterward, designed alloys are fabricated using cold crucible levitation melting technique. The microstructure and mechanical performances of newly designed alloys are characterized in this work using scanning electron microscope and universal testing machine, respectively. Each alloy demonstrates monolithic β phase except Ti-35Nb-3Fe-9Zr alloy which display dual α″ + β phases. Typically, niobium acts as an isomorphous beta stabilizer. However, in this work, formation of martensitic α″ phases occurs at 35 wt % of niobium among the series of newly designed alloys. Furthermore, none of the alloys fail till the maximum load capacity of machine, i.e., 100 KN except Ti-35Nb-3Fe-9Zr alloy. Moreover, the Vickers hardness test is carried out on Ti-xNb-3Fe-9Zr alloys which demonstrate slip bands around the indentation for each alloy. Notably, the deformation bands and cracks around the indentations of each alloy have been observed using optical microscopy; Ti-35Nb-3Fe-9Zr demonstrates some cracks along with slip bands around its indentation. The Ti-25Nb-3Fe-9Zr alloy shows the highest yield strength of 1043 ± 20 MPa, large plasticity of 32 ± 0.5%, and adequate hardness of 152 ± 3.90 Hv among the investigated alloys. The Ti-25Nb-3Fe-9Zr alloy demonstrates good blend of strength and malleability. Therefore, Ti-25Nb-3Fe-9Zr can be used effectively for the biomedical applications.

Empirical Testing of Beta Stability in Indian Capital Market

The study tests stability of CAPM beta in the Indian capital market. Beta is one of the debated issues in the finance literature. While Fama and French have argued that betas are no more relevant in the capital market, it is one of the prominent concepts used by the finance professionals worldwide. The study is based on NSE Nifty companies, Nifty and Sensex Indices prices from 2009 to 2019. We use market model on the sample data to assess the beta stability for different time periods. The result of the present study shows that betas of companies do not show any stability over the period of time, but weighted average portfolio beta shows some stability during the study period.

Commissioning and performance of TITAN’s Multiple-Reflection Time-of-Flight Mass-Spectrometer and isobar separator

TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) has specialized in fast Penning Trap mass spectrometry of very short-lived radioactive isotopes. The facility has been upgraded with a Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-TOF-MS) to continue its quest towards more exotic nuclides, which are critical for our understanding of nuclear structure effects far from the valley of beta stability and for the nucleosynthesis of heavy elements in explosive astrophysical environments. In this publication, we discuss the implementation, operation and performance of TITAN’s MR-TOF-MS as a stand-alone high-precision mass spectrometer and as an isobar separator. By using the novel mass-selective re-trapping technique for the isobar separation, the MR-TOF-MS can consecutively perform separation and mass measurement of the same ion population, acting as its own isobar separator. The device boosts the dynamic range and reach of the TITAN facility by several orders of magnitude. The MR-TOF-MS reaches a high mass resolving power (m/Δm∼400000), high precision and mass accuracy (δm/m<10−7), is fast (common cycle time 20ms), shows high sensitivity and very large dynamic range (ion of interest to contaminant ratios of up to 1 to 106).

Role of stress-induced martensite on damage behavior in a metastable titanium alloy

In general, stress-induced martensite (SIM) is frequently employed to enhance the strain hardening behavior of Ti alloys through a so-called transformation-induced plasticity (TRIP) effect. However, the SIM does not necessarily lead to the improved mechanical performance of Ti alloys with the underlying mechanism unclear yet. The present work investigates the damage behavior of a typical model metastable Ti-1023 alloy with dominant SIM using uniaxial tensile test and nano-indentation measurement. The full beta microstructure with varied grain size (70 μm-350 μm) is obtained in the present Ti-1023 alloy through careful heat treatments. The integrated mechanical and microstructural characterizations indicate that the SIM displays a dual impact on the damage behavior of the present Ti-1023 alloy. In particular, the SIM could either facilitate the nucleation of cracks or inhibit the propagation of cracks depending on the martensitic lath spacing. The above dual-impact of SIM on the damage of Ti-1023 alloy can be rationalized based on the competing role of martensitic lath spacing on the dislocation pile-up and damage nucleation at lath boundaries. The dislocation-based plasticity could additionally assist the crack blunting. The effect of the beta stability on the damage behavior is found to be indirectly determined by the martensitic lath spacing. Since the martensitic lath spacing is mainly governed by the beta grain size, the present work suggests that the grain boundary engineering should be harnessed to fully explore the potential of SIM in developing strong and ductile/tough Ti alloys for broad industrial applications.

A Simple Analysis on Return Predictability of Beta Estimation Error

자본자산가격이론(CAPM)은 주식시장에서 광범위하게 쓰이는 모형이지만, 그 핵심인 베타 추정치의 통계적 안정성에는 많은 의구심이 있어 왔다. 이 논문에서는 한국 주식시장에서 베타의 안정성, 혹은 불확정성이 미치는 효과를 횡단면 실증분석을 실시하였다. CAPM 회귀모형의 표준오차를 베타의 불확정성으로 측정하여 이 불확정성이 미래의 주식 수익률에 미치는 영향을 분석하여보니 비대칭적인 영향이 있음을 확인하였다. 또한 가치나 규모와 같은 전통적인 가격산정 요인에의 노출과도 밀접한 관련이 있다는 사실 또한 확인하였다.CAPM is a widely used pricing model in the stock market, and the stability of the estimated beta has been in question in the literature. This paper empirically studies the effect of beta stability or uncertainty on cross-sectional stock returns in the Korean market. By considering the standard error of CAPM regression as a measure for beta uncertainty, we find that beta uncertainty has asymmetric effects on stock returns. We also report that our finding is closely related to the factor exposures, such as market and value factors.