Management of Choledocholithiasis: Should We Remove the Bile Duct?

Retrieval of stone by endoscopic papillotomy, laparoscopic choledochotomy or open choledochotomy is the treatment of choice for choledocholithiasis. Published literature shows that the recurrence rate is 4% to 24% with existing method of treatment. We have treated 8 patients who admitted with recurrent choledocholithiasis in the department of Hepato-Biliary-Pancreatic and Liver Transplant Surgery, Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh in the period of January 2016 to December 2019. None had intrahepatic duct abnormality or stones. All patients underwent either ERCP stenting, open choledocholithotomy or both 16 to 84 months back. Management policy is designed and outcome is observed on these patients. There were 3 males and 5 females; age ranges 18 to 60 years. The common bile duct (CBD) diameter of all patient ranges from 15 to 24mm. The shape of CBD is different from normal variant; S shaped, saculated, grossly dilated with terminal narrowing. Considering the anatomical abnormality and recurrence of disease we have removed the abnormal part of common bile duct along with stones and the operation was completed by Roux-en-Y hepaticojejunostomy. All patients were completely symptom free for 6 to 48 months after surgery. Removal of abnormal part of common bile duct with reconstruction in the form of Roux-en-Y hepatico-jejunostomy may be considered for treating choledocholithiasis with abnormal CBD (abnormally dilated, abnormally shaped, angulated or sacculated) however, long-term follow up is required for final comment.

Simple Treadmill Score: Does It Have Better Predictability for Coronary Artery Disease?

Coronary artery disease is one of the most prevalent causes of increasing mortalitiy in current time. Early detection of such dreadful condition by a non-invasive test like exercise treadmill test, is a much-required option to prevent future complications like myocardial infarction. The aim of this study was to find out how different the predictability of simple treadmill score in comparison to other treadmill scores namely the well-known Duke treadmill score and Cleveland clinic score. In a cross-sectional analytical study of total 130 individuals with stable angina were included according to criteria set before the study. The treadmill scores of these patients were calculated and compared to coronary angiogram findings where coronary artery angiograms were done according to clinical need. Simple treadmill test had similar predictability for coronary artery disease when we compared it with much-applied Duke Treadmill Test and Cleveland Clinic Score- which is currently used for mortality prediction. Receiver Operator Characteristics (ROC) Curve showd all scores had around 0.7 area under the curve (AUC) which is highly statistically significant (p<0.0001) though simple treadmill score in females has higher sensitivity (92.3%). Simple treadmill score can be considered to exclude female patients from undergoing invasive investigation as it has higher sensitivity than other currently practiced treadmill scores i.e., Duke treadmill score.

Health Problems of Bangladeshi Tannery Workers

Tanners are exposed to raw hides as well as to various toxic chemicals. The study was intended to find out the health problems among tannery workers. This descriptive cross-sectional study was conducted in 2019 among 223 workers working with raw hides and chemicals selected by stratified random sampling in ten tanneries of Leather Industry Area, Hemayetpur, Savar, Dhaka, Bangladesh. Data were collected by the principal investigator after taking informed written consent from the tanners using a pre-tested interview schedule and a check-list. Data were cross-checked for consistency and accuracy. All relevant ethical issues including approval from Institutional Review Board (IRB), and data quality assurance issues were taken into consideration. Analysis of data was carried out by using computer software SPSS version 20.0 with anonymity. Descriptive statistics were used to describe the data, while Chi-square test was carried out to measure statistical association. As many as 97(43.5%) workers were in age group of 15 to 24 years with a mean age of 28.4±9.5 years. An overwhelming majority 204(91.5%) were males, three-fifths 134(60.1%) of the workers were married, while 213(95.5%) tanners had religion Islam. Majority 122(54.7%) tanners had primary level of education, whereas 56(25.1%) had secondary level and 44(19.7%) had no formal schooling. The mean monthly family income was 13744.4±3485.5 Taka. More than three-fourths 170(76.2%) workers had more than four family members with over half 114(51.1%) of the workers were smokers. Of 223, over half 124(55.6%) of the workers were affected with at least one health problem. Majority of the workers suffered from skin diseases (51.6%), musculoskeletal disorders (33.1%), gastrointestinal problems (22.6%), chronic headache (14.5%) and respiratory problems (14.5%). Only 9(4.0%) workers had pre-placement orientation, while 196(66.4%) workers did not notice the necessity for pre-placement training. Of ten tanneries, cent per cent had foul smell, 80.0% each had poor lighting and discomfort temperature, 60.0% had intolerable noise, 50.0% were with poor ventilation system, and only 30.0% had adequate waste management facilities. The tanneries did not have medical facilities even for emergency conditions. Health problems are significantly associated with job duration (p<0.01), working sections (p<0.05) and smoking status (p<0.001) of the workers. The overall environment of the tanneries is far from satisfactory. Skin diseases, musculoskeletal disorders, gastrointestinal problems, chronic headache and respiratory diseases are the common identified health problems. A considerable number of workers are unconcerned for the pre-placement orientation, and do not use Personal Protective Equipments (PPEs). As a rule, Personal Protective Equipments (PPEs) are not made available to workers by the tannery authorities, and lack of treatment facilities of the tanneries is a common place.

Knowledge and Preventive Practice on COVID-19 among Civil Employees Working In Selected Unit of Dhaka Cantonment

Corona viruses are a large group of viruses that are responsible for sickness starting from mild common cold to extremely severe form of diseases. Prevention is the best method to control COVID-19 pandemic. The World Health Organization recommended that generating awareness by enriching knowledge of people to rule out COVID-19. To find out the level of knowledge and status of preventive practice on COVID-19 among Civil employees of Central Ordnance Depot (COD) and Central Mechanical Transport Depot (CMTD) of Dhaka Cantonment. This descriptive cross-sectional study was conducted among 151 civil employees of COD (Central Ordnance Depot) and CMTD (Central Mechanical Transport Depot), Dhaka cantonment from July 2020 to June 2021. Systematic random sampling technique was used to select the respondents. Data collection was done by face to face interview with using semi-structured questionnaire. The mean age of the respondent was 37.94±10.12 years. Among the respondents 84.8% were male, rest 15.2% were female. Mean score of knowledge highest (17.73) in 18-29 years age group, in female (17.83), 2nd class employee (18.00) and those qualified in graduation and above (17.27). Regarding level of knowledge 77.48% respondents had excellent knowledge, of which most of them were doing practice. The association between knowledge and preventive practice of COVID-19 on hand washing (p=0.01), wearing face mask (p=0.000), maintaining social distance (p=0.002) were found statistically significant. In this study most of the respondents had 'excellent' and 'good' level of knowledge on COVID-19, of which most of them were doing practice. There are some, those who had knowledge but not doing practice. On the other hand some had no knowledge on particular event of COVID-19, but were doing practice unknowingly.

Post-Operative Severe Hyperbilirubinemia: A Case Report

Hyperbilirubinemia is commonly seen in medical practice. But what could be the highest level of bilirubin in an individual that is still an unanswered question. We came across to a 37 years old lady in October 2018 with hepaticolithiasis who underwent extended choledocholithotomy. Her preoperative serum bilirubin was within normal range. Post-operatively she developed cholangitis and from 3rd post-operative day onwards she developed severe hyperbilirubinemia, which was high as 70.47 mg/dl on the 6th post-operative day. Other causes of post-operative hyperbilirubinemia were excluded. She was managed conservatively for this hyperbilirubinemia and bilirubin level gradually reduced.

Optimisation and stability of Rh particles on noble metal films immobilised on H + conducting solid polymer electrolyte in attaining efficient nitrate removal

During the electrocatalytic reduction of nitrate, nitrite is often evolved as a product along with ammonia due to the sluggish nitrite to ammonia conversion process compared to the nitrate to nitrite conversion step. Rhodium metal has been proven to enhance nitrite to ammonia conversion rates, yielding ammonia as the only final product. In the present article, we have shown how effectively Rh nanoparticles immobilized on Pt and Pd films deposited on H +  conducting Nafion-117 membranes eliminate intermediate nitrite ions during the progress of the nitrate reduction reaction in a flow type reactor. In this research, we also demonstrated the optimization of Rh nanoparticles on the cathode surface to attain effective nitrate reduction along with a reproducibility check. The dissolution of loosely held Rh nanoparticles on the cathodic surface was observed, which tends to redeposit during cathodic electrolysis, causing stable performance. Finally, Tafel analysis was performed to show the relative kinetic feasibility of the Rh modified Pt and Pd electrodes in attaining nitrate reduction reactions in neutral medium.

Mixed Micellization, Thermodynamic and Adsorption Behavior of Tetracaine Hydrochloride in the Presence of Cationic Gemini/Conventional Surfactants

In this approach, tensiometry and UV-visible techniques are used to determine the effect of cationic gemini and conventional surfactants on tetracaine hydrochloride (TCH), an anesthetic drug. We have estimated micellar, interfacial, and energetic constraints. To gain a deep understanding of their mixed association behavior, the outputs were examined using different theoretical models. The critical micelle concentration for single and mixed amphiphiles was estimated. The cmc values of mixed amphiphiles were found between the individual amphiphiles due to strong attractive interaction (synergism) between the components after mixing. The non-ideal behavior of mixtures was confirmed by the larger values of ideal cmc than the experimental cmc values. The negative values of interaction parameter (β) and values of activity coefficients less than unity indicate strong synergistic interaction between drug and surfactant. The stability of the mixed systems is demonstrated by the negative Gibbs free energy of micellization and excess free energy of micellization. In contrast to a single chain surfactant, a double chain surfactant (gemini) exhibits better interactions with the drug. Spectral measurements (UV-visible spectra) were used to monitor the binding of the drug with surfactant (conventional as well as gemini). Studying these mixed aggregates could help to optimize their compositions and find synergistic properties between TCH monomers and surfactants.

Metal-Organic Frameworks Derived Electrocatalysts for Oxygen and Carbon Dioxide Reduction Reaction

The increasing demands of energy and environmental concerns have motivated researchers to cultivate renewable energy resources for replacing conventional fossil fuels. The modern energy conversion and storage devices required high efficient and stable electrocatalysts to fulfil the market demands. In previous years, we are witness for considerable developments of scientific attention in Metal-organic Frameworks (MOFs) and their derived nanomaterials in electrocatalysis. In current review article, we have discussed the progress of optimistic strategies and approaches for the manufacturing of MOF-derived functional materials and their presentation as electrocatalysts for significant energy related reactions. MOFs functioning as a self-sacrificing template bid different benefits for the preparation of metal nanostructures, metal oxides and carbon-abundant materials promoting through the porous structure, organic functionalities, abundance of metal sites and large surface area. Thorough study for the recent advancement in the MOF-derived materials, metal-coordinated N-doped carbons with single-atom active sites are emerging candidates for future commercial applications. However, there are some tasks that should be addressed, to attain improved, appreciative and controlled structural parameters for catalytic and chemical behavior.

Evaluation of outcome of Coronavirus disease 2019 patients receiving RAAS inhibitors (OCRAS study): a prospective observational study of Bangladeshi hypertensive patients

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Beximco Pharmaceutical Limited, Bangladesh

OnBehalf

Cardiology Study Group (Bangladesh)

Background

The fact that SAARS-Cov2 virus enters cells through ACE2 receptors and the Renin-Angiotensin-Aldosterone System Inhibitors (RAASi) upregulate the ACE2 receptors, there was speculation that use of RAASi may lead increased cellular entry of the virus.  There was a pause for a brief period of the use of RAASi in COVID 19 patients. But clinically the speculation has been found to be incorrect. Different professional societies come up with the assertion to continue to use RAASi. As the hesitancy among the clinicians appears to continue and there is no first hand data regarding the safety of the use of RAASi in Bangladeshi population, the study was undertaken to evaluate the safety of RAASi in COVID 19 patients.

Aims & Methods

This study was a prospective, observational multi-center study to evaluate the outcome of COVID-19 patients receiving RAAS inhibitors. Adult Hypertensive patients (age ≥18 years) with diagnosed COVID-19 confirmed by RT-PCR test who have a history of taking either ACE inhibitor/ARB or any other anti-hypertensive medication. Evaluation of outcome was assessed by rate of hospitalization, requirement of oxygen therapy, requirement of high flow nasal cannula, admission to ICU and mortality between two groups. All statistical analyses were performed using SPSS for Windows, version 20.0 (SPSS Inc., Chicago, IL, USA).

Results

We collected data from 147 Covid-19 positive patients confirmed by RT-PCR. Among them, 117 (79.6%) had a history of taking RAAS inhibitor and 30 had history of taking other antihypertensive medications. Of them, two-third patients had more than 50 years of age and more than half of the patients had overweight or obesity. Other than hypertension they had several comorbidities such as Diabetes Mellitus (45.4%), Ischemic Heart Diseases (35.4%), Asthma or COPD (15%) etc. Rate of hospitalization had no statistical difference between RAAS inhibitor group and other hypertensive group (48.7% vs 46.70% respectively; p-value - 0.841). There was no statistical difference between two groups in terms of requirement of oxygen therapy (p-value - 0.297), High Flow Nasal Cannula (p-value - 0.430), intensive care unit (p-value - 0.194) and death (p-value – 0.383) also. Almost half and one-third of the patients had persistence of symptoms even after 14 days and 28 days respectively. Fatigue, cough, breathlessness, loss of appetite and taste were the most common symptoms among those.

Conclusion

In our study we found that RAAS inhibitor treatment had no adverse effect on the outcome of COVID-19 patients compared with other antihypertensive drugs. Patients may continue receiving ACEIs and ARBs for the treatment of any indication for RAASi without an increased risk of worse outcomes.

Effect of Humidity and Temperature on the Impedances and Voltage of Al/Gr-Jelly/Cu-Rubber Composite-Based Flexible Electrochemical Sensors

Here we present the fabrication of graphene and jelly (superabsorbent polymer) electrolyte composite-based shockproof flexible electrochemical sensors (Al/Gr-Jelly/Cu) and their properties under the effect of humidity and temperature. A layer of graphene mixed in jelly electrolyte was drop-casted onto porous rubber substrates between preliminary fixed aluminum (Al) and copper (Cu) electrodes followed by rubbing-in. It was observed that the graphene and jelly mixture was mechanically soft and flexible, similar to jelly. Electrically, this mixture (graphene and jelly) behaved as a flexible electrolyte. It was observed that under the effect of humidity ranging from 47 to 98%, the impedances of the sensors decreased by 2.0 times on average. Under the effect of temperatures ranging from 21 to 41 °C the impedances decreased by 2.4 times. The average temperature coefficient of impedances was equal to −0.03 °C⁻¹. The electrochemical voltage generated by the flexible jelly electrolyte sensors was also investigated. It was found that the initial open-circuit voltages were equal to 201 mV and increased slightly, by 5–10% under the effect of humidity and temperature as well. The short-circuit currents under the effect of humidity and temperature increased by 2–3 times. The Al/Gr-Jelly/Cu electrochemical sensors may be used as prototypes for the development of the jelly electronic-based devices.

Heavy metals contamination and associated health risks in food webs-a review focuses on food safety and environmental sustainability in Bangladesh

Heavy metals occur naturally in very small amounts in living organisms, but exposure to their higher concentrations is hazardous. Heavy metals at hazardous levels are commonly found in foodstuffs of Bangladesh, mainly due to the lack of safety guidelines and poor management of industrial effluents. Several lines of evidence suggest that the level of heavy metals in foodstuffs of Bangladesh is higher than the acceptable limits set by World Health Organization/Food and Agriculture Organization. Literature survey revealed that the sources and transport pathways of heavy metals in the ecosystem and the abundance of heavy metals in the food products of Bangladesh are potential threats to food safety. However, an extensive assessment of the toxicity of heavy metals in food webs is lacking. Although widespread heavy metal contamination in various foodstuffs and environmental matrices have been summarized in some reports, a critical evaluation regarding multi-trophic transfer and the health risk of heavy metal exposure through food chain toxicity in Bangladesh has not been performed. This systematic review critically discussed heavy metal contamination, exposure toxicity, research gaps, existing legislation, and sustainable remediation strategies to enhance Bangladesh's food safety. In particular, this study for the first time explored the potential multi-trophic transfer of heavy metals via food webs in Bangladesh. Furthermore, we recommended a conceptual policy framework to combat heavy metal contaminations in Bangladesh.

Role of Rotaviral Antigen Detection by ICT in Acute Diarrhoeic Children below 5 Years in a Tertiary Care Hospital of Bangladesh

Rotavirus is responsible for acute severe watery diarrhoea in young children. Early and rapid detection of Rotavirus infection can help to reduce inappropriate administration of antibiotics and has future positive impact on prevention of drug resistance. This cross-sectional study was designed to determine the role of Rotaviral antigen detection by ICT from stool sample of acute diarrhoeal children below five years admitted in Sylhet MAG Osmani Medical College Hospital, Sylhet and was carried out in the Department of Microbiology in collaboration with the Department of Paediatrics during the period from 1st January 2018 to 31st December 2018. Total 184 children of under five years of age with acute watery diarrhoea were enrolled in this study. Rotaviral antigen was detected by ELISA (Enzyme Linked Immunosorbent Assay) and ICT (Immunochromatographic test) from stool samples. Out of 184 stool samples, Rotaviral antigen was found positive in 84 and 86 cases by ICT and ELISA methods, respectively. ICT showed sensitivity of 90.70% and specificity of 93.88% when compared with ELISA. The Rotavirus infection was found highest in male children (61.90%) and in age group of 7 to 12 months (51.89%). Considering the importance of Rotaviral diarrhoea, rapid detection of Rotavirus infection by ICT is essentially needed and might be practiced routinely as it is relatively reliable, easy to perform and cost-effective. It is particularly important in Bangladesh, where diarrhoea is still contributing a significant proportion of morbidity and mortality in under five children.

Pattern of Glomerular Disease in a Tertiary Care Hospital of Bangladesh

Glomerular disease is one of the most important causes of chronic kidney disease in developing countries like Bangladesh as well as the whole world. The pattern of glomerular disease varies in different countries and can have different clinical presentations. The aim of the study was to analyze the clinical profile and to determine the histological pattern of glomerular diseases in a large tertiary care hospital in Bangladesh. All kidney biopsies performed in Mymensingh Medical College Hospital, Bangladesh from October 2018 to March 2020 were prospectively analyzed in the study. A total of 101 patients with kidney biopsy were examined by clinical and laboratory findings and by light and immuno-fluorescence microscopy. The mean age was 30.0±14.6 years and 50(49.5%) were male and 51(50.5%) were female with a male to female ratio of 1:1. The clinical syndromes namely nephrotic syndrome, nephritic syndrome, nephrito-nephrotic presentation, RPGN like presentation, macroscopic haematuria and asymptomatic urine abnormality were present in 31.7%, 34.5%, 22.8%, 11.9%, 19.8% and 10.9% patients respectively. The most common histological varieties found in the study were mesangial proliferative glomerulonephritis (MesPGN) (18.8%) and focal segmental glomerulosclerosis (FSGS) (18.8%). Other histopathological pattern among the studied subjects revealed minimal change disease (MCD) in 5.9%, membranous nephropathy (MN) in 7.9%, membranoproliferative glomerulonephritis (MPGN) in 16.8%, IgA nephropathy in 5%, IgM nephropathy in 2%, IgG nephropathy in 2%, diffuse proliferative glomerulonephritis (DPGN) in 1%, focal proliferative glomerulo-nephritis (FPGN) in 3%, crescentic GN in 3%, lupus nephritis (LN) in 13.9%, amyloidosis in 1% and fibrillary glomerulopathy in 1% patient. The pattern of glomerular disease found in this study was similar to other studies performed in Bangladesh with a little variation. It may guide the future researchers to establish a national kidney biopsy registry in Bangladesh.

Short Term Outcome of Therapeutic ERCP in the Management of Biliary Ascariasis in a Tertiary Care Hospital of Bangladesh

The history of ascariasis is very old. It is endemic in various parts of Bangladesh. Hepatobiliary ascariasis is a well-known complication of the intestinal ascariasis. Although cosmopolitan, it predominantly affects people in Asia, Africa, and South America. This was a prospective observational study conducted from July to December 2014 to explore the short term outcome of therapeutic ERCP in the treatment of biliary ascariasis in a tertiary care hospital of Bangladesh. A total of 60 cases of biliary ascariasis were selected conveniently in this study. Data were collected by face-to-face interviews and observation with the help of data sheet. Data were checked for quality control and analyzed by computer using SPSS software. The mean±SD age of the patients was 30.96±7.66 years. All the patients were aged between 17 and 55 years and predominantly affect women in the 3rd and 4th decades. The most common presentation was upper abdominal pain in 47(83.32%) of the patients. Ultrasound was the diagnostic tool of choice, where biliary ascariasis was found in 40(66.7%) of patients. ERCP is reserved mainly for therapeutic purposes and found successful in 57(95%) of the patients.

Development of L-cysteine sensor based on thallium oxide coupled multi-walled carbon nanotube nanocomposites with electrochemical approach

Here, Nanocomposites of thallium oxide doped multi-walled carbon nanotube (Tl2O.MWCNT NCs) were prepared by utilizing the wet-chemical method (WCM) in an alkaline phase at low temperature. Different optical procedures (FTIR: Fourier Transform Infra-Red Spectroscopy, XRD: Powder X-ray diffraction, FESEM: Field-Emission Scanning Electron Microscopy, XEDS: X-ray Electron Dispersive Spectroscopy, TEM: Tunneling Electron Microscopy, and XPS: X-ray photoelectron spectroscopy) were used to fully characterize (Optical, structural, crystalline, morphological, and elemental etc.) of the prepared Tl2O.MWCNT NCs. Modification of the thin-layer with NCs onto glassy carbon electrode (GCE) is prepared and applied for the enzyme-free detection of selective and sensitive L-cysteine by electrochemical approach. Using a reliable current-voltage approach, analytical sensing indexes such as sensitivity, LDR, LOD, LOQ, durability, and interference were assessed by fabricated sensor probe (GCE/Tl2O.MWCNT NCs/CPM) in selective detection of L-cysteine in a room condition, whereas nafion was used as conducting polymer matrix (CPM) during the fabrication of GCE with NCs. L-cysteine calibration plot was found to be linear over an extensive range of concentration. The calibration curve was used to calculate the sensing parameters such as sensitivity (316.46 pAμM-1cm-2), LOD down to (~18.90 ± 1.89 pM), and LOQ (63.0 pM) of the prepared sensor. The use of a simple WCM to validate the Tl2O.MWCNT NCs is a good approach for developing a NCs-based sensor for enzyme-free biomolecule identification and detection in the biomedical and health care fields in a broad scale. This proposed sensor (GCE/Tl2O.MWCNT NCs/CPM) is used to detect selective L-cysteine in real biological samples such as human, mouse, and rabbit serum and found acceptable and satisfactory results.

Analysis of cold-start NO2 and NOx emissions, and the NO2/NOx ratio in a diesel engine powered with different diesel-biodiesel blends

In the transportation sector, the share of biofuels such as biodiesel is increasing and it is known that such fuels significantly affect NOx emissions. In addition to NOx emission from diesel engines, which is a significant challenge to vehicle manufacturers in the most recent emissions regulation (Euro 6.2), this study investigates NO₂ which is a toxic emission that is currently unregulated but is a focus to be regulated in the next regulation (Euro 7). This manuscript studies how the increasing share of biofuels affects the NO₂, NOx, and NO₂/NOx ratio during cold-start (in which the after-treatment systems are not well-effective and mostly happens in urban areas). Using a turbocharged cummins diesel engine (with common-rail system) fueled with diesel and biofuel derived from coconut (10 and 20% blending ratio), this study divides the engine warm-up period into 7 stages and investigates official cold- and hot-operation periods in addition to some intermediate stages that are not defined as cold in the regulation and also cannot be considered as hot-operation. Engine coolant, lubricating oil and exhaust temperatures, injection timing, cylinder pressure, and rate of heat release data were used to explain the observed trends. Results showed that cold-operation NOx, NO₂, and NO₂/NOx ratio were 31-60%, 1.14-2.42 times, and 3-8% higher than the hot-operation, respectively. In most stages, NO₂ and the NO₂/NOx ratio with diesel had the lowest value and they increased with an increase of biofuel in the blend. An injection strategy change significantly shifted the in-cylinder pressure and heat release diagrams, aligned with the sudden NOx drop during the engine warm-up. The adverse effect of cold-operation on NOx emissions increased with increasing biofuel share.

Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process

Herein, novel Co₃O₄·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles’ structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/μ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/μ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/μ-Chip sensor, such as excellent sensitivity (1.3842 µAµM⁻¹cm⁻²), a wide linear dynamic range of 1.0 nM–2.0 mM (R² = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/μ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

Sensitive Detection of Thiourea Hazardous Toxin with Sandwich-Type Nafion/CuO/ZnO Nanospikes/Glassy Carbon Composite Electrodes

In this research study, we developed a voltammetric electrochemical sensor probe with a copolymer Nafion (Sulfonated Tetrafluoroethylene-based Fluoro-polymer) decorated with hydrothermally prepared sandwich-type CuO/ZnO nanospikes (NSs) onto a glassy carbon electrode (GCE) for reliable thiourea (TU) detection. The detailed characterizations in terms of structural morphology, binding energy, elemental compositions, grain size and crystallinity for synthesized NSs were performed by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis, respectively. The differential pulse voltammetric (DPV) analysis for TU showed good linearity at current-versus-TU concentration on the calibration plot in the 0.15~1.20 mM range, which is defined as a dynamic detection range (LDR) of TU in a phosphate buffer solution. Considering the slope of LDR over the GCE-coated NSs surface area (0.0316 cm2), the TU sensor sensitivity (0.4122 µA µM-1 cm-2) was obtained. Besides this, the low limit (LOD) for TU detection was calculated and found to be 23.03 ± 1.15 µM. The fabricated Nafion/CuO/ZnO NSs/GCE sensor probe was created as a reliable sensor based on reproducibility, interference effect, stability and response time. Real bio-samples were investigated and the results confirm the anticipated reliability of the TU sensor probe. Thus, this is a noble way to develop enzyme-free electrochemical sensors that could be an alternative approach for the detection of chemicals in the field of enzyme-free biosensor development technology.

Bacillus-Mediated Silver Nanoparticle Synthesis and Its Antagonistic Activity against Bacterial and Fungal Pathogens

In this article, the supernatant of the soil-borne pathogen Bacillus mn14 was used as the catalyst for the synthesis of AgNPs. The antibacterial and antifungal activity of Bs-AgNPs was evaluated, in which S. viridans and R. solani showed susceptibility at 70 µL and 100 µL concentrations. Enzyme properties of the isolates, according to minimal inhibitory action and a growth-enhancing hormone-indole acetic acid (IAA) study of the isolates, were expressed in TLC as a purple color with an Rf value of 0.7. UV/Vis spectroscopy revealed the presence of small-sized AgNPs, with a surface plasmon resonance (SPR) peak at 450 nm. The particle size analyzer identified the average diameter of the particles as 40.2 nm. The X-ray diffraction study confirmed the crystalline nature and face-centered cubic type of the silver nanoparticle. Scanning electron microscopy characterized the globular, small, round shape of the silver nanoparticle. AFM revealed the two-dimensional topology of the silver nanoparticle with a characteristic size ranging around 50 nm. Confocal microscopy showed the cell-wall disruption of S. viridans treated with Bs-AgNPs. High-content screening and compound microscopy revealed the destruction of mycelia of R. solani after exposure to Bs-AgNPs. Furthermore, the Bs-AgNPs cured sheath blight disease by reducing lesion length and enhancing root and shoot length in Oryza sativa seeds. This soil-borne pathogen Bacillus-mediated synthesis approach of AgNPs appears to be cost-efficient, ecofriendly, and farmer-friendly, representing an easy way of providing valuable nutritious edibles in the future.