Scorpion venoms are complex polypeptide mixtures, the ion channel blockers and antimicrobial peptides being the best studied components. The coagulopathic properties of scorpion venoms are poorly studied and the data about substances exhibiting these properties are very limited. During research on the Heterometrus laoticus scorpion venom, we have isolated low-molecular compounds with anticoagulant activity. Determination of their structure has shown that one of them is adenosine, and two others are dipeptides LeuTrp and IleTrp. The anticoagulant properties of adenosine, an inhibitor of platelet aggregation, are well known, but its presence in scorpion venom is shown for the first time. The dipeptides did not influence the coagulation time in standard plasma coagulation tests. However, similarly to adenosine, both peptides strongly prolonged the bleeding time from mouse tail and in vitro clot formation in whole blood. The dipeptides inhibited the secondary phase in platelet aggregation induced by ADP, and IleTrp decreased an initial rate of platelet aggregation induced by collagen. This suggests that their anticoagulant effects may be realized through the deterioration of platelet function. The ability of short peptides from venom to slow down blood coagulation and their presence in scorpion venom are established for the first time. Further studies are needed to elucidate the precise molecular mechanism of dipeptide anticoagulant activity.

It is well-known that drugs administered into an organism intravenously or through the gastrointestinal tract are degraded by enzymes of the body, reducing their therapeutic effect. One of the ways to decrease this undesirable process is through the inclusion of drugs in nanomaterials. Earlier strong anticoagulant activity was demonstrated for dipeptide IleTrp (IW) and adenosine (Ado). In this work, the effect of inclusion in nanomaterials on the biological activity of IW and Ado was studied. For this purpose, Ado and IW were incorporated into thermosensitive nanogel composed of pluronic P123-grafted heparin. The prepared nanocarrier was characterized by transmission electron microscopy, dynamic light scattering, and ζ-potential. Biological activity was determined by measuring the bleeding time from mouse tail in vivo and the time of clot formation in vitro. It was found that encapsulation of Ado and IW into nanomaterial significantly increased their effects, resulting in an increase in the bleeding time from mouse tail and clot formation time. Thus, inclusion of low molecular weight anticoagulants Ado and IW into nanomaterials may be considered a way to increase their biological activity. physical protection from environmental stimuli and may target the load to specific sites [8]. Making these systems stimuli-responsive is an efficient way to improve their functions. Use of stimulus-sensitive polymers for the manufacture of smart drug delivery systems and/or active targeting delivery systems may greatly increase the therapeutic efficacy of drugs and biologically active molecules [9,10].Among many other nanomaterials, nanogels can be used as biodegradable and highly efficient carriers for the transportation of drugs and controlled drug release [11,12]. Encapsulation in nanogels is widely used to enhance solubility and stability, e.g., for anticancer drugs. This is especially important for the peptides; loading peptides into nanogel increases their stability and reduces acute toxicity. In fact, several types of nanocarriers have performed their roles in the field very well. Thus, poly(lactide-co-glycolide)-poly(ethylene imine) nanoparticles effectively delivered superoxide dismutase to the cytoplasm via direct translocation and endocytosis-endosomal escape pathways [6]. Mesoporous silica-based nanoparticles have been used for encapsulation and targeted delivery of several proteins and peptides [13]. Along this line, heparin and its derivatives were utilized to deliver many kinds of drugs or bioactive molecules via heparin-drug conjugate, drug-loaded polymeric nanoparticles or nanogels, nanosized complexation, and heparin-coated organic or inorganic nanoparticles [14][15][16]. These heparin-based carriers have been used in various applications, thereby improving the bioavailability and the therapeutic efficacy of drugs or biologically active compounds. The anticoagulant properties of the heparin itself were improved by covalent attachment to the outer surface of the colloidal mesoporous silica nanoparticles [17]. T...

Chromolaena odorata is a medicinal herb with prominent pharmacological properties. The therapeutic efficiency of Chromolaena odorata extracts and its ingredients have, however, been limited by various factors, including the lack of targeting capacity and poor bioavailability. To approach this drawback, ethyl acetate fraction extract of Chromolaena odorata- (EA.ChO-) encapsulated pluronic-based nanocarriers was disclosed herein. The most common pluronic triblock copolymer micelles (pluronic F127) was used for the nanosized formulation of Chromolaena odorata extract. The obtained results show that EA.ChO-encapsulated nanoparticles have a spherical morphology with a designed hydrodynamic size was about 183.7 nm and zeta potential -39.5 mV. The EA.ChO nanoparticles are stable in different aqueous solutions (water, PBS 2.8, and PBS 7.4). The lyophilized form of the EA.ChO nanoparticles exhibited excellent stability for long-term storage. Notably, the EA.ChO nanoparticles were 1.3-1.4 fold more effective in the growth of fibroblast than the free EA.ChO, verifying the potential of pluronic F127 nanoparticles to the increased function of EA.ChO in the proliferation of fibroblast cell. In addition, bleeding stopped within 55 ± 6  s which was 20 s faster than that of free EA.ChO and 38-44 s faster than that of negative control treatments. The EA.ChO nanoencapsulation processed a rapid blood clot formation compared to control, free EA.ChO, pluronic F127, and water, suggesting the excellent bioavailability of EA.ChO nanoencapsulation. The obtained results thus provided a promising prospect for raising the activity Chromolaena odorata extract in wound healing application.

The purpose of the study is to find the factors that influence the financial leverage of Vietnam firms. The dependent variable is the financial leverage and the independent variables are firm size, asset structure, liquidity, growth opportunities, profitability, and firm age. The data are collected from Vietnam firms' annual financial reports in the period from 2010 to 2019. The study uses a sample of 448 Vietnam listed firms in the period. We also employ a panel regression model with pooled OLS and fixed effect to analyze the firms' financial data. The results of the model showed that financial leverage (FL) has a negative relationship with some factors such as asset structure (AS), liquidity (LQ), growth opportunities (GRW), profitability (ROA), and firm age (AGE) in the fixed effect regression. It means that when liquidity, profitability, and firm age increase, firms' financial leverage will decrease. While firms' financial leverage has still a positive relationship with the firm size (SIZE) in the model. As a result, when firm size increases, financial leverage will increase, too. The results showed that models are fit for the research and can be used to predict future findings. It is also useful for enterprises, financial advisors, investors, as well as the financial managers.

This paper reports a study that examines the effects of text-based incidental vocabulary learning on EFL high school students’ reading comprehension and explores their attitudes toward text-based incidental vocabulary learning. It was a quasi-experimental study with 70 students from a high school in Kien Giang province. These students were divided into two groups: the control group and the experimental group. The quantitative data from reading tests (for pre-test and post-test) were used to examine students’ reading comprehension over eight weeks. Questionnaires and the qualitative analysis from semi-structured interviews focus on their attitudes towards text-based vocabulary learning in reading comprehension. The findings indicate that text-based incidental vocabulary learning influenced positively students’ reading comprehension after the treatment and that students yielded positive attitudes towards text-based incidental vocabulary learning in their reading lessons.<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0302/a.php" alt="Hit counter" /></p>