bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forecasting the volatility of Chinese stock market: An international volatility index
Authors: Lei Likun , Zhang Yaojie , Wei Yu , Zhang Yi 
Published: July 2020

AbstractTo forecast the volatility of Chinese stock market, we use information from 28 international markets rather than relying on the Chinese market alone. A common factor, which we call the international volatility index, is constructed by the first principal component of all the 28 cross‐national stock market volatilities. We then add the international volatility index into the prevailing heterogeneous autoregressive model of realized volatility (HAR‐RV). The in‐sample estimation results show that the impact of this common index on future Chinese market volatility is statistically significant and positive. More importantly, the out‐of‐sample forecasting results suggest that our proposed model outperforms competing models including the HAR‐RV, kitchen sink model, and combination approaches. The results are similar when we use a wide range of robustness checks. Furthermore, the international volatility index also yields the highest economic value from an asset allocation perspective.
Short‐selling costs and asymmetric price response to economic shocks: A transaction cost explanation to price overshooting
Authors: Ornelas José Renato Haas , de Carvalho Pablo José Campos 
Published: July 2020

AbstractWe propose a model that combines performance‐based arbitrage, short‐sale constraints, and costly arbitrage. In the model, good earnings surprises trigger short‐covering causing price overshooting for highly shorted stocks. However, price overshooting is on average lower than short‐selling costs. Model predictions are empirically tested using Brazilian short‐selling data. We find empirical support for the short‐covering and overshooting phenomena. Furthermore, there is evidence that the intensity of overshooting is lower than the short‐selling borrowing fee, for both U.S. and Brazilian markets. Theoretical and empirical results suggest that arbitrageurs behave asymmetrically to good and bad earnings news.
Mapping US presidential terms with S&P500 index: Time series analysis approach
Authors: Gil‐Alana Luis A. , Mudida Robert , Yaya OlaOluwa S. , Osuolale Kazeem A. , Ogbonna Ahamuefula E. 
Published: July 2020

AbstractThis paper maps the US presidential terms with price dynamics in US stock markets by focusing on the S&P500 index. Fractional integration techniques, which are more general than other standard methods, are used and the results obtained produce interesting findings. It was found that during the second presidential terms, S&P500 stock market is less efficient and present higher degrees of persistence in its volatility. This is observed independently of the political affiliations of the president in power. The volatility, in general, reflects the spillover of economic excesses at the end of the first presidential term when seeking re‐election into the second term in office. Expansionary monetary and fiscal policies at the end of the first term may create disequilibria in the economy which are amplified in the second term through a transmission mechanism resulting in contractionary interventionist policies in a situation where no incentive for re‐election exists by the incumbent. The existence of stock's price cycles as induced by US presidential terms contradicts market efficiency theory but this helps investors decisions.
Do staggered board elections affect firms' financing costs? Evidence from China
Authors: Yugang Chen , Yu Liu , Shahab Yasir , Yuan Zhou 
Published: July 2020

AbstractAs an important provision in a company's charter, the requirement of staggered board elections can help management protect themselves or protect the interests of investors. We examined a unique dataset of Chinese listed firms from the period of 2004–2014, and our findings are twofold. First, we find that the establishment of a staggered board in a company's article of association increases the equity financing costs as well as the debt financing costs. This result is in line with management defense hypothesis that staggered boards are an overprotection for the management. Second, our results show that a cumulative voting system plays an effective role in reducing the impact of a staggered board on a firm's financing costs. This moderating impact is higher for the debt financing costs and lower for the equity financing costs. The result shows that “debt investors” value a cumulative voting system because of its control of the corporate operations and board activities, while “equity investors” believe staggered board elections have a larger influence on the corporate governance.
Oil and currency volatilities: Co‐movements and hedging opportunities
Authors: Olstad Aleksander , Filis George , Degiannakis Stavros 
Published: July 2020

AbstractThe current literature concentrates its attention to the interactions between oil and exchange rates, focusing only on the first moments. Extending this line of research, we investigate the time‐varying correlation between the volatilities of two oil benchmarks (Brent and WTI) and six currencies of the major oil‐importers and oil‐exporters, for the period from February 1, 1999 to May 30, 2016, using a Diag‐BEKK model. The optimal portfolio weights and hedge ratios for portfolios comprised of the aforementioned volatilities, are also examined. The analysis reveals that oil and currency volatilities exhibit positive correlations during major global or region‐specific economic events (such as the Global Financial Crisis of 2007–2009 and the EU debt crisis period). By contrast, country‐specific events yield heterogeneous time‐varying correlations between oil and the different currencies in our sample. Both the optimal portfolio weights and optimal hedge ratios estimations demonstrate a time‐varying behaviour, suggesting that continuous portfolio rebalancing is necessary for diversification purposes. The findings also show that risk reduction based on the optimal portfolio weight strategy is primarily beneficial for oil volatility investors, whereas currency volatility investors achieve better hedging using the optimal hedge ratio strategy.
Do financial constraints really matter? A case of understudied African firms
Authors: Machokoto Michael 
Published: July 2020

AbstractUsing a system of equations to account for the simultaneity, inter‐temporal and interdependent nature of corporate decisions, we document several new insights into how emerging market firms allocate funds across competing uses‐of‐funds. Emerging market firms save most of the operating cash flow. When the firms spend, they allocate the remainder to dividend payments first, followed by debt retirements, then equity repurchases and lastly investments. This pecking order of prioritizing savings and dividends ahead of other uses‐of‐funds highlight difficulties in accessing external finance and a stubbornly resilient signalling motive for firms operating under a high degree of information asymmetry and agency costs. We further find significant asymmetry and heterogeneity in the allocation of funds conditional on credit constraints, deviations from target and around the financial crisis. Our findings signal the need for policies that improve access to external finance and information disclosure in emerging markets.
Foreign equity portfolio flow and corruption: A cross‐country evidence
Authors: Kwabi Frank , Boateng Agyenim , Fosu Samuel , Zhu TingTing , Chijoke‐Mgbame Marian 
Published: July 2020

AbstractThis study examines the impact of foreign equity portfolio investment on corruption. Employing a large dataset of 44 countries from 2001 to 2015 and three different measures of corruption, our results show that foreign investors from well‐governed countries tend to foster public accountability, reduce asymmetry information and corruption. We find empirical evidence that foreign equity portfolio investment interacts with stock market development and central bank transparency to reduce corruption. Our results suggest that stock market development and central bank transparency are regarded as complementary by international portfolio investors. Further analysis indicates that corruption appears more prevalent in countries where domestic investors dominate the stock market. Our results are robust to endogeneity using dynamic generalized methods of moments (GMM). The findings suggest that attracting foreign equity investors reduces corruption, implying significant benefits for portfolio diversification.
Identification of continuous immunoglobulin G epitopes of Dermatophagoides farinae allergens by peptide microarray immunoassay
Authors: Teng Feixiang , Han Feifei , Zhu Xuming , Yu Lili , Gai Dongzheng , Xu Cong , Cui Yubao 
Published: July 2020

AbstractDermatophagoides farinae, as a common house dust mite species, is one of the main sources of allergens in the world. At present, Dermatophagoides farinae is found to contain more than 30 groups of allergens. These allergens are used for allergen‐specific immunotherapy (AIT) of allergic diseases. During the AIT process, immunoglobulin G (IgG) antibodies can block immunoglobulin E (IgE) antibody‐induced allergic reactions in the human body. One of the mechanisms may be that IgG and IgE competitively bind to the same allergic protein, so it is necessary to explore the binding sites (epitopes) of IgG antibodies to allergens. In this study, peptide arrays were constructed to react with the serums from patients with allergic asthma to find the IgG epitopes of several allergens including major allergens (Der f 1, 2) and mid‐tier allergens (Der f 4, 5, and 7), and then verified by enzyme‐linked immunosorbent assay (ELISA) test. Relevant epitopic sequences were located on the tertiary structure of individual allergens, as reconstructed by homology modeling. One IgG epitope of Der f 1 (90–106aa, NVPSELDLRSLRTVTPI), five IgG epitopes of Der f 4 (61–77aa, ERYQPVSYDIHTRSGDE; 193–209aa, FRSDASTHQWPDDLRSI; 226–242aa, HPFIYHETIYYGGNGIN; 271–287aa, LRWLRNFGTEWGLVPSG; 352–368aa, NDWVGPPTDQHGNILSV), and one IgG epitope of Der f 5 (84–101aa, RYNVEIALKSNEILERDL) were identified. IgG epitopes of Der f 2, 7 were not found. There are overlaps between the IgG and IgE epitopes of Der f 1, 4, and 5. These findings not only reflect the practicality of peptide array and ELISA test in the allergen IgG epitope identification, but also provide more information for further understanding of the human immunological changes during AIT and the molecular mechanisms of IgG blocking IgE activity.
Oleuropein protects against lipopolysaccharide‐induced sepsis and alleviates inflammatory responses in mice
Authors: Alsharif Khalaf F. , Almalki Abdulraheem A. , Al‐Amer Osama , Mufti Ahmad H. , Theyab Abdulrahman , Lokman Maha S. , Ramadan Shimaa S. , Almeer Rafa S. , Hafez Mohamed M. , Kassab Rami B. , Abdel Moneim Ahmed E. 
Published: July 2020

AbstractSepsis results from a major systemic inflammatory response and can induce disorders in multiple organs. The present study evaluated the potential protective effects of oleuropein (OLE) against hyperinflammatory responses during lipopolysaccharide (LPS)‐induced sepsis in mice. Sixty male Balb/c mice were randomly categorized into five groups of 12 animals each: control, intraperitoneally injected with OLE (50 mg/kg), injected with LPS (10 mg/kg, intraperitoneal), and two groups administered OLE (25 and 50 mg/kg) for 3 days prior to LPS injection. Twenty‐four hours after lipopolysaccharide injection, the animals were sacrificed. Serum, liver, and kidney tissue samples were collected for biochemical analyses, histopathological examinations, and investigation of inflammation‐related gene expression. OLE pretreatment significantly reduced liver damage parameters (alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase) and kidney damage parameters (blood urea nitrogen, creatinine, and kidney injury molecule‐1) in the septic mice. OLE pretreatment ameliorated LPS‐induced liver and kidney histological changes. OLE significantly mitigated the increased levels of malondialdehyde in the liver and kidneys and reduced levels of reduced glutathione induced by LPS. LPS injection also resulted in increased expression of the proinflammatory cytokines (TNF‐α, IL‐1β, and IL‐6) and inflammation‐related genes (Nos2, Hmgb1, Mpo, Cd46, Map2k4, and Map2k7) in the hepatic and renal tissues. OLE reduced these expressions to ameliorate the inflammatory response. Moreover, OLE pretreatment enhanced the survival rate of septic mice. In conclusion, OLE alleviated the inflammatory response to protect against LPS‐induced sepsis in mice.
The influence of structure and morphology on ion permeation in commercial silicone hydrogel contact lenses
Authors: Saez‐Martinez Virginia , Mann Aisling , Lydon Fiona , Molock Frank , Layton Siân A. , Toolan Daniel T. W. , Howse Jonathan R. , Topham Paul D. , Tighe Brian J. 
Published: July 2020

AbstractThe importance of the microstzructure of silicone hydrogels is widely appreciated but is poorly understood and minimally investigated. To ensure comfort and eye health, these materials must simultaneously exhibit both high oxygen and high water permeability. In contrast with most conventional hydrogels, the water content and water structuring within silicone hydrogels cannot be solely used to predict permeability. The materials achieve these opposing requirements based on a composite of nanoscale domains of oxygen‐permeable (silicone) and water‐permeable hydrophilic components. This study correlated characteristic ion permeation coefficients of a selection of commercially available silicone hydrogel contact lenses with their morphological structure and chemical composition. Differential scanning calorimetry measured the water structuring properties through subdivision of the freezing water component into polymer‐associated water (loosely bound to the polymer matrix) and ice‐like water (unimpeded with a melting point close to that of pure water). Small‐angle x‐ray scattering, and environmental scanning electron microscopy techniques were used to investigate the structural morphology of the materials over a range of length scales. Significant, and previously unrecognized, differences in morphology between individual materials at nanometer length scales were determined; this will aid the design and performance of the next generation of ocular biomaterials, capable of maintaining ocular homeostasis.
Protective roles and mechanisms of rosmarinic acid in cyclophosphamide‐induced premature ovarian failure
Authors: Yao Yang , Xu Yinglei , Wang Yong 
Published: July 2020

AbstractThe aim of this study was to investigate the protective effect of rosmarinic acid (RA) in a premature ovarian failure (POF) mouse model and the potential mechanisms. The POF model was induced by a single intraperitoneal injection of 120 mg/kg cyclophosphamide (CP). Additionally, 40 mg/kg RA was administered for 7 days before CP injection. The concentration of sex hormones was determined by fluorescence immunohistochemistry. Histological analysis was performed after ovarian tissue sections were stained with hematoxylin and eosin. The expression of the NLRP3 inflammasome was examined by western blot analysis and polymerase chain reaction. The expression of apoptosis markers of cytochrome c and caspase‐3 was also detected by western blot analysis and immunohistochemistry. The results showed that RA not only decreased the ovarian index in POF mice but also improved the abnormal secretion of reproductive hormones associated with POF. Treatment with RA suppressed the ovarian expression of the NLRP3 inflammasome and regulated the ovarian expression of apoptosis‐related proteins. The results suggested that RA exhibited a protective effect against CP‐induced POF potentially by suppressing apoptosis and the NLRP3 inflammasome.
Quantitative proteomics reveals the regulatory networks of circular RNA BTBD7_hsa_circ_0000563 in human coronary artery
Authors: Chen Jia‐Xin , Hua Lei , Zhao Chen‐Hui , Jia Qiao‐Wei , Zhang Jing , Yuan Jin‐Xia , Zhang Yong‐Jie , Jin Jian‐Liang , Gu Mu‐Feng , Mao Zhi‐Yuan , Sun Hai‐Jian , Wang Lian‐Sheng , Ma Wen‐Zhu , Jia En‐Zhi 
Published: July 2020

AbstractBackgroundBTBD7_hsa_circ_0000563, which is located on chromosome 14, contains conserved binding sites with miR‐155/130a and RNA‐binding proteins according to bioinformatic prediction. We investigated the association of BTBD7_hsa_circ_0000563 expression in coronary artery segments with atherosclerotic stenosis and identified the proteome‐wide BTBD7_hsa_circ_0000563‐regulated proteins in human coronary artery.MethodsThe atherosclerotic grade and extent in coronary artery segments were determined by hematoxylin and eosin staining. BTBD7_hsa_circ_0000563 expression in eight coronary artery segments from one patient was quantified by RT‐qPCR assay. A proteomic approach was adopted to reveal significant differences in protein expression between among four groups differing in their BTBD7_hsa_circ_0000563 expression levels.ResultsThe RT‐qPCR assay revealed that coronary artery segments with severe atherosclerotic stenosis had significantly low BTBD7_hsa_circ_0000563 levels. The proteomic analysis identified 49 differentially expressed proteins among the segment groups with different BTBD7_hsa_circ_0000563 expression levels, of which 10 were downregulated and 39 were upregulated with increases in the BTBD7_hsa_circ_0000563 level. The 10 downregulated proteins were P61626 (LYSC_HUMAN), P02760 (AMBP_HUMAN), Q02985 (FHR3_HUMAN), P01701 (LV151_HUMAN), P06312(KV401_HUMAN), P01624 (KV315_HUMAN), P13671 (CO6_HUMAN), P01700(LV147_HUMAN), Q9Y287(ITM2B_HUMAN), and A0A075B6I0 (LV861_HUMAN). The top 10 upregulated proteins were Q92552 (RT27_HUMAN), Q9UJY1(HSPB8_HUMAN), Q9Y235(ABEC2_HUMAN), P19022 (CADH2_HUMAN), O43837(IDH3B_HUMAN), Q9H479(FN3K_HUMAN), Q9UM22(EPDR1_HUMAN), P48681(NEST_HUMAN), Q9NRP0(OSTC_HUMAN), and Q15628(TRADD_HUMAN).ConclusionBTBD7_hsa_circ_0000563 is involved in the atherosclerotic changes in human coronary artery segments. Verification, mechanistic, and function studies are needed to confirm whether patients with coronary artery disease would benefit from such personalized medicine in the future.
Lutein inhibits breast cancer cell growth by suppressing antioxidant and cell survival signals and induces apoptosis
Authors: Kavalappa Yogendra Prasad , Gopal Sowmya Shree , Ponesakki Ganesan 
Published: July 2020

AbstractReduced risk of breast cancer upon intake of lutein‐rich food supplements creates an interest to investigate the molecular mechanism underlying the growth inhibitory potential of lutein in MCF‐7 and MDA‐MB‐231 cells. Lutein purified from Spinacia oleracea was identified by high‐performance liquid chromatography and liquid chromatography–mass spectrometry. The cell viability was measured by water‐soluble tetrazolium‐1 assay. The intracellular reactive oxygen species level was examined by 2′,7′‐dichlorofluorescein assay. The protein expression of the markers of antioxidant defense, cell survival, and apoptosis was analyzed by western blot analysis. The induction of apoptosis by lutein was measured by 4′,6‐diamidino‐2‐phenylindole staining and caspase‐3 activity assay. The purified lutein inhibited the viability of MCF‐7 and MDA‐MB‐231 cells. The growth inhibitory effect of lutein was associated with suppressed protein expression of superoxide dismutase‐2 and heme oxygenase‐1, and its transcription factor nuclear factor erythroid 2‐related factor‐2. Lutein treatment subsequently blocked the expression of intracellular cell survival proteins, phosphorylated protein kinase B, phosphorylated extracellular‐regulated kinase 1/2, and nuclear factor‐kB. Suppression of antioxidant defense and cell survival markers by lutein was further linked to apoptosis induction with elevated caspase‐3 activity and downregulated expression of Bcl‐2 and poly‐ADP ribose polymerase. Our results emphasize a significant role of lutein as an effective inhibitor of human breast cancer cell growth that activates cell death partly through the modulation of antioxidant defense response‐linked cell survival signaling markers.
NPY promotes macrophage migration by upregulating matrix metalloproteinase‐8 expression
Authors: Wu Weiqiang , Peng Song , Shi Yanchuan , Li Linyu , Song Zhiyuan , Lin Shu 
Published: July 2020

AbstractMacrophage migration is thought to participate in obesity‐related cardiovascular diseases. Matrix metalloproteinase‐8 (MMP‐8) possesses proteolytic activity on the extracellular matrix (ECM), which promotes macrophage migration to the site of vascular injury. Neuropeptide Y (NPY) is a bioactive peptide involved in MMP expression. However, it is uncertain whether NPY can regulate the expression of matrix metalloproteinase‐8 (MMP‐8) in macrophages. In this study, wild‐type C57BL/6 and NPY−/− mice were fed a high‐fat diet and subjected to subcutaneous carotid artery injury with ferric chloride, to observe the role of NPY and macrophages in neointima formation. In addition, Raw264.7 cells were treated with NPY and its antagonists to observe MMP‐8 expression and macrophage migration. We found that NPY−/− mice exhibited significantly reduced neointima formation after carotid artery injury. The content of macrophages and MMP‐8 in the neointima and media were also significantly reduced in NPY−/− mice compared with C57BL/6 mice. Moreover, the expression of MMP‐8 in macrophages was also decreased in NPY−/− mice. NPY increased MMP‐8 messenger RNA and protein expression in Raw264.7 cells in vitro, and this effect was abrogated by the Y1R antagonist. In addition, NPY increased the phosphorylation of ERK1/2, which was significantly attenuated by co‐treatment with the Y1R antagonist. Moreover, NPY‐induced MMP‐8 expression could be decreased by the ERK1/2 inhibitor PD98059. Furthermore, NPY promoted macrophage migration across type I collagen in vitro. In conclusion, NPY promotes macrophage migration by upregulating MMP‐8 expression, which we believe to be an underappreciated mechanism of the increased progression of neointima formation.
Recombinant l‐asparaginase production using Pichia pastoris (MUTs strain): establishment of conditions for growth and induction phases
Authors: Pillaca‐Pullo Omar , Rodrigues David , Sánchez‐Moguel Ignacio , Lopes André , Pimenta Marcela , Basi Tajindar , Feitosa Valker , Iris Zavaleta Amparo , Monteiro Gisele , Pessoa Jr Adalberto , Vitolo Michele 
Published: July 2020

AbstractBACKGROUNDl‐asparaginase (ASNase), a biopharmaceutical enzyme used in the treatment of childhood lymphoid malignancies, is commercially produced from Escherichia coli and Erwinia chrysanthemi. However, it causes severe adverse effects due to allergenic prokaryotic epitopes on the protein surface. ASNase II from Saccharomyces cerevisiae can be a promising alternative source of this enzyme. In this study, conditions to produce ASNase from S. cerevisiae expressed in Pichia pastoris have been investigated in shake flasks and 3 L‐bioreactor. We evaluated if medium composition, concentration of carbon source (i.e. glycerol), growth time, concentration of inducer (i.e. methanol), temperature and initial pH influenced both biomass and ASNase expression.RESULTSBiomass of around 53 g L–1 and ASNase volumetric activity of 710 U L–1 were achieved using the buffered glycerol‐complex medium (BMGY) containing 40 g L–1 glycerol, with induction after 141 h using 3.0% (v/v) methanol, at 20 °C and initial pH 6.0.CONCLUSIONThe experiments performed in shake flasks were scalable to a 3 L‐bioreactor, suggesting that this bioprocess could be scaled‐up for industrial production. © 2020 Society of Chemical Industry (SCI)