Different signal-transforming algorithms were applied for UV spectrophotometric analysis of paracetamol, ibuprofen, and caffeine in ternary mixtures. Phosphate buffer pH 7.2 was used as the spectrophotometric solvent. Severe overlapping spectra could be resolved into individual bands in the range of wavelengths 200–300 nm by using Savitzky–Golay smoothing and differentiation, trigonometric Fourier series, and mother wavelet functions (i.e., sym6, haar, coif3, and mexh). To optimize spectral recoveries, the concentration of various types of divisors (single, double, and successive) was tested. The developed spectrophotometric methods showed linearity over the ranges 20–40 mg/L for paracetamol, 12–32 mg/L for ibuprofen, and 1–3.5 mg/L for caffeine (R2 > 0.990). They could be successfully applied to the assay and dissolution test of paracetamol, ibuprofen, and caffeine in their combined tablets and capsules, with accuracy (99.1–101.5% recovery) and precision (RSD < 2%). For comparison, an isocratic RP-HPLC analysis was also developed and validated on an Agilent ZORBAX Eclipse XDB–C18 (150 × 4.6 mm, 5 µm) at an ambient temperature. A mixture of methanol : phosphate buffer 0.01 M pH 3 (30 : 70 v/v) was used as the mobile phase delivered at 2 mL/min, and the effluent was monitored at 225 nm. It was shown that spectrophotometric data were statistically comparable to HPLC p>0.05, suggesting possible interchange between UV spectrophotometric and HPLC methods for routine analysis of paracetamol, ibuprofen, and caffeine in their solid pharmaceutical dosage forms.

The paper investigates the effect of cash flow on the operational efficiency of non-financial companies listed on the Vietnam stock market, spanning the period from 2010 to 2019. The research results indicate that operating cash flow in the business positively affects operational efficiency, measured through two indicators of Returns on assets (ROA) and Returns on equity (ROE). The effect remains stronger for firms that have state ownership. We also address an endogeneity issue through a two-stage least square and Generalized method of moments. The results are robust through several cross-sectional heterogeneities such as firm size or firm age and other estimation techniques. Investment opportunities (Market-to-Book) and the growth of total assets (Firm growth) also positively affect the firm's performance. On the contrary, the target of company size (Firm size) and the debt ratio (Firm leverage) negatively influence operational efficiency. The paper highlights the importance of cash flow management and provides recommendations for regulators and managers to improve firms' operational efficiency.

Objective: The purpose of this study was to translate, adjust and evaluate the validity and reliability of the Champion's Health Belief Model scale, so as to measure the beliefs of self-examination practices of Vietnamese women. Material and Methods: The adaptation and psychometric characteristics test of the Vietnamese HBM scale was performed, with 40 participants, from October 2021 to June 2022. Of these, 10 women were initially randomized to adjust the translation version, and 30 women were to evaluate the reliability of the scale. The content value of the scale is measured by the opinion of 5 experts. Reliability was measured by Cronbach's alpha, while An estimation of stability is commonly assessed by a test–retest reliability analysis (ICC). Result: The Vietnamese version of the Health Belief Model scale (V-HBMS) demonstrated good content validity, with the Items content validity index (I-CVI) score for all 42 items> 0.79. Internal consistency with Cronbach's alpha ranges from .715 to .954 and the reliability of the ICC re-test ranged from .954-.000 (p-value = 0.000) determined with good results. Conclusion: The Vietnamese version of the Health Belief Model scale can be considered a valid tool to survey the belief of Vietnamese women in the implementation of breast self-examination behavior.