Determination of Formaldehyde Content by High Performance Liquid Chromatography in Some Fruits of Local Market in Dhaka City, Bangladesh

The present study was conducted to determine the formaldehyde content in three mostly consumed fruits (mango, apple and grape) in Bangladesh. A total of 81 samples were collected from three different local markets of Dhaka city (Mohammadpur Bazaar, Mohakhali Bazaar and Gulistan Bazaar). High Performance Liquid Chromatography (HPLC) with c-18 column and UV detector at 355 nm were used to determine the formaldehyde content. The mobile phase was 50% acetonitrile with a flow rate 1ml/min. The concentration of formaldehyde in mango was from 1.86mg/100g to 11.65mg/100g in Mohammadpur Bazaar, 1.45mg/100g to 10.69mg/100g in Mohakhali Bazaar and 1.69mg/100g to 4.41mg/100g in Gulistan Bazaar. It was found that 2.28mg/100g to 7.30mg/100g, 2.33mg/100g to 11.77mg/100g & 1.42mg/100g to 5.39mg/100g formaldehyde contained in apple for Mohammadpur, Mohakhali, Gulistan Bazaar respectively. Among the selected sample, the content of formaldehyde in grape was lower than mango and apple. The amount of formaldehyde in grape was 0.93mg/100g to 4.63mg/100g, 1.92mg/100g to 3.84mg/100g & 1.42mg/100g to 4.92mg/100g for Mohammadpur, Mohakhali, Gulisthan market. The highest formaldehyde concentrations (11.77mg/100g) were detected in apple fruit, exceeding the naturally found permissible limit of 0.63 to 2.23 mg/100gm; the second highest formaldehyde concentration (11.65mg/100g) were found in mango, exceeding the permissible limit of 0.1 to 6 mg/100gm; while the grape also contains high level of formaldehyde concentration (4.92mg/100g) exceeding the permissible limits 2.24mg/100gm. It was surprisingly found that the 22.22% of mango, 85.19% of apple and 66.67% of grape contained formalin above the permissible limit. Keywords: Fruits, Formaldehyde, HPLC, Food Safety DOI: 10.7176/FSQM/96-06 Publication date: April 30th 202

Integrating Explainability into Graph Neural Network Models for the Prediction of X-ray Absorption Spectra

The use of sophisticated machine learning (ML) models, such as graph neural networks (GNNs), to predict complex molecular properties or all kinds of spectra has grown rapidly. However, ensuring the interpretability of these models’ predictions remains a challenge. For example, a rigorous understanding of the predicted X-ray absorption spectrum (XAS) generated by such ML models requires an in-depth investigation of the respective black-box ML model used. Here, this is done for different GNNs based on a comprehensive, custom-generated XAS data set for small organic molecules. We show that a thorough analysis of the different ML models with respect to the local and global environments considered in each ML model is essential for the selection of an appropriate ML model that allows a robust XAS prediction. Moreover, we employ feature attribution to determine the respective contributions of various atoms in the molecules to the peaks observed in the XAS spectrum. By comparing this peak assignment to the core and virtual orbitals from the quantum chemical calculations underlying our data set, we demonstrate that it is possible to relate the atomic contributions via these orbitals to the XAS spectrum

Integrating Explainability into Graph Neural Network Models for the Prediction of X-ray Absorption Spectra

The use of sophisticated machine learning (ML) models, such as graph neural networks (GNNs), to predict complex molecular properties or all kinds of spectra has grown rapidly. However, ensuring the interpretability of these models’ predictions remains a challenge. For example, a rigorous understanding of the predicted X-ray absorption spectrum (XAS) generated by such ML models requires an in-depth investigation of the respective black-box ML model used. Here, this is done for different GNNs based on a comprehensive, custom-generated XAS data set for small organic molecules. We show that a thorough analysis of the different ML models with respect to the local and global environments considered in each ML model is essential for the selection of an appropriate ML model that allows a robust XAS prediction. Moreover, we employ feature attribution to determine the respective contributions of various atoms in the molecules to the peaks observed in the XAS spectrum. By comparing this peak assignment to the core and virtual orbitals from the quantum chemical calculations underlying our data set, we demonstrate that it is possible to relate the atomic contributions via these orbitals to the XAS spectrum

Toxicity outcome of concurrent teletherapy and brachytherapy compared with teletherapy followed by brachytherapy in locally advanced carcinoma cervix

Background: Teletherapy and intracavitary brachytherapy are definitive treatment modalities for stages IIB to IVA cervical carcinoma. Globally, it is the second most common cancer among female. Majority of patients attend the hospital with locally advanced stage due to less screening facility and social stigma.Methods: This quasi-experimental study was conducted from January 2019 to June 2020 with a total of 76 patients. The patients were equally divided into two groups: A and B after obtaining their informed written consent.Results: Final follow up was given after completion of treatment at 24 weeks. Patients in both groups developed grade 1 gastrointestinal and genitourinary toxicities (10.5% versus 13.1%, 13.1% versus 15.7% in group A and B respectively). Two patients in group A and three patients in group B developed grade 2 gastrointestinal toxicities. In genitourinary toxicities, grade 2 toxicities were observed in two patients of group A and four patients of group B, (p>0.05). None developed grade 3 and 4 gastrointestinal and genitourinary toxicities. There were no statistically significant variations in treatment related toxicities between the two groups.Conclusions: Both gastrointestinal, genitourinary toxicities were comparable between two groups. The toxicities were acceptable and well tolerated.

Photophysics of indole upon x-ray absorption

A photofragmentation study of gas-phase indole (C$_8$H$_7$N) upon single-photon ionization at a photon energy of 420 eV is presented. Indole was primarily inner-shell ionized at its nitrogen and carbon $1s$ orbitals. Electrons and ions were measured in coincidence by means of velocity map imaging. The angular relationship between ionic fragments is discussed along with the possibility to use the angle-resolved coincidence detection to perform experiments on molecules that are strongly oriented in their recoil-frame. The coincident measurement of electrons and ions revealed fragmentation-pathway-dependent electron spectra, linking the structural fragmentation dynamics to different electronic excitations. Evidence for photoelectron-impact self-ionization was observed.Comment: 11 pages, 6 figure

Randomized controlled trial of standard versus double dose cotrimoxazole for childhood pneumonia in Pakistan

Objective: Increasing concern over bacterial resistance to cotrimoxazole, which is recommended by WHO as a first-line drug for treating non-severe pneumonia, led to the suggestion that this might not be optimal therapy. However, changing to alternative antimicrobial agents, such as amoxicillin, is costly. We compared the clinical efficacy of twice-daily cotrimoxazole in standard versus double dosage for treating non-severe pneumonia in children.Methods: A randomized controlled multicentre trial was implemented in seven hospital outpatient departments and two community health programmes. A total of 1143 children aged 2-59 months with non-severe pneumonia were randomly allocated to receive 4 mg trimethoprim plus 20 mg sulfamethoxazole/kg of body weight or 8 mg trimethoprim plus 40 mg sulfamethoxazole/kg of body weight orally twice-daily for 5 days Treatment failure occurred when a child required a change of therapy, died or was lost to follow-up. Children required a change of therapy if their condition worsened (they developed chest indrawing or danger signs) or if at 48 hours after enrollment, their clinical condition was the same (defined as having a respiratory rate that was 5 breaths/minute higher or lower than at the time of enrollment).Findings: The results of 1134 children were analysed: 578 were assigned to the standard dose of cotrimoxazole and 556 to the double dose. Treatment failed in 112 children (19.4%) in the standard group and 118 (21.2%) in the double-dose group (relative risk 1.10; 95% confidence interval = 0.87-1.37). Using multivariate analysis we found that treatment was more likely to fail in children who were not given the medicine correctly (P = 0.001), in those younger than 12 months (P = 0.004), those who had used antibiotics previously (P = 0.002), those whose respiratory rate was \u3e or =20 breaths/minute above the age-specific cut-off point (P = 0.006), and those from urban areas (P = 0.042).Conclusion: Both standard and double strength cotrimoxazole were equally effective in treating non-severe pneumonia. Close follow-up of patients is essential to prevent worsening of disease. Definitions of clinical failure need to be more specific. Surveillance in both rural and urban areas is essential in the development of treatment policies that are based on clinical outcomes

Reconstructing the infrared spectrum of a peptide from representative conformers of the full canonical ensemble

Leucine enkephalin (LeuEnk), a biologically active endogenous opioid pentapeptide, has been under intense investigation because it is small enough to allow efficient use of sophisticated computational methods and large enough to provide insights into low-lying minima of its conformational space. Here, we reproduce and interpret experimental infrared (IR) spectra of this model peptide in gas phase using a combination of replica-exchange molecular dynamics simulations, machine learning, and ab initio calculations. In particular, we evaluate the possibility of averaging representative structural contributions to obtain an accurate computed spectrum that accounts for the corresponding canonical ensemble of the real experimental situation. Representative conformers are identified by partitioning the conformational phase space into subensembles of similar conformers. The IR contribution of each representative conformer is calculated from ab initio and weighted according to the population of each cluster. Convergence of the averaged IR signal is rationalized by merging contributions in a hierarchical clustering and the comparison to IR multiple photon dissociation experiments. The improvements achieved by decomposing clusters containing similar conformations into even smaller subensembles is strong evidence that a thorough assessment of the conformational landscape and the associated hydrogen bonding is a prerequisite for deciphering important fingerprints in experimental spectroscopic data.</p

High Harmonic Generation in Mixed Xuv and Nir Fields at a Free-Electron Laser

We Present the Results of an Experiment Investigating the Generation of High-Order Harmonics by a Femtosecond Near-Infrared (NIR) Laser Pulse in the Presence of an Extreme Ultraviolet (XUV) Field Provided by a Free-Electron Laser (FEL), a Process Referred to as XUV-Assisted High-Order Harmonic Generation (HHG). Our Experimental Findings Show that the XUV Field Can Lead to a Small Enhancement in the Harmonic Yield When the XUV and NIR Pulses overlap in Time, while a Strong Decrease of the HHG Yield and a Red Shift of the HHG Spectrum is Observed When the XUV Precedes the NIR Pulse. the Latter Observations Are in Qualitative Agreement with Model Calculations that Consider the Effect of a Decreased Number of Neutral Emitters but Are at Odds with the Predicted Effect of the Correspondingly Increased Ionization Fraction on the Phase Matching. Our Study Demonstrates the Technical Feasibility of XUV-Assisted HHG Experiments at FELs, Which May Provide New Avenues to Investigate Correlation-Driven Electron Dynamics as Well as Novel Ways to Study and Control Propagation Effects and Phase Matching in HHG

Association of clinico-epidemiological features with locally advanced stage of cervical cancer patients presenting at Bangabandhu Sheikh Mujib Medical University, Bangladesh

Cervical cancer is one of the most prevalent gynecological cancers in women in Bangladesh. The objective of this study was to assess the clincoepidemiological association with the histology of locally advanced cervical cancer. We have done this observational study in the department of Clinical Oncology at Bangabandhu Sheikh Mujib Medical University from July to December 2019. Sixty-six biopsy-proven locally advanced (stage IIB to IVA) squamous cell carcinoma of uterine cervix were included in this study. The mean age of patients at diagnosis was 48.5 (±8.6) years. Commonly observed epidemiological characteristics of locally advanced carcinoma cervix were illiteracy (46.9%), oral contraceptive use (62.1%), multi para (78.7%) and early marriage (74.2%). Most frequent clinical presentation was post-coital bleeding (37.87%). Most patients presented in stage IIB (65.1%). The association of the stages of the disease with age, parity, oral contraceptive use, age at marriage and clinical presentation were statistically nonsignificant, whereas illiteracy was statistically significant. Most women had poor awareness regarding their need for routine check-up and screening as indicated by the late medical care seeking. Social stigma might have played some role. Relevant programmes should create awareness among women, especially those with socioeconomic deprivation. BSMMU J 2022; 15(3): 175-17