Macromolecular Symposia最新文献

Polymers have been used significantly in MEMS (micro-electro-mechanical systems) biosensors as substrates, sensor materials, packaging, surface encapsulation, and transducer elements. The sensing layer is a component that interacts with the target molecule. The choice of material for the sensing layer affects the sensitivity of the sensor. This research explores four commonly used polymers (polydimethylsiloxane (PDMS), nylon, poly methyl methacrylate) (PMMA), and polyethylene) as a sensor layer for bio-recognition in MEMS biosensors. The study is simulation-based. Two models, namely, a simple micro-cantilever beam and piezoelectric cantilever MEMS, are regarded in the paper. Different properties, such as stress and displacements, are studied, as well as voltage, in the case of the piezoelectric model. The comparative study contributes to understanding how different polymer materials and readout methods impact the choice of material for the sensing layer for MEMS biosensors. Results show that for applications using displacement measurement for further analysis, a simple cantilever is more suitable. The PED model has low displacement sensitivity but is an excellent choice when electric output is required. PDMA shows the best results among the materials used for comparative analysis. The final choice of materials depends on the specific application; PDMA provides flexibility and ease of fabrication, whereas PMMA is more suitable for applications requiring rigidity and chemical resistance. PDMA has 1.63 times more voltage sensitivity than PMMA. Furthermore benefits and challenges of using polymer as a sensing layer are also discussed.

Microbial fuel cells are utilized in electromicrobiology for the purpose of cleaning wastewater and producing electricity. Anaerobically, MFCs use microbial catalysis in the anodic compartment to transform the chemical energy stored in organic and inorganic molecular bonds. Using the soil sample, four exoelectrogens are isolated. Each of the four single-chambered mediator-less microbial fuel cell design are used to inject the extracted soil exoelectrogens. A nutritional medium is used to operate the reactors in batches of 15 days. The exoelectrogen ISO4 (Bacillus amyloliquefaciens strain NSB4), followed by ISO3 (cereus strain BXC6), ISO2 (Bacillus sp. (in: Bacteria) strain 4N), and ISO1 (Staphylococcus argenteus strain D7) achieve the best growth rates. On average, data on energy generation shows that MFCs with ISO4 have the maximum voltage and power density at 1024 mV external resistance (1 kΩ), followed by ISO3 at 609 mV, ISO2 at 560  mV, and ISO1 at 487 mV. Power densities of isolates are recorded as: 41.281 mW/m², 29.241, 12.723, and 3.552 mW/m² for ISO4, ISO3, ISO2, and ISO1, respectively. The research finds that the energy output of MFC reactors is affected by the exoelectrogen substrates. Cyclic voltammetry (CV) experiment demonstrates that exoelectrogens directly transport electrons to the anode surface via cytochromes and other substances associated with the cell membrane. It has been previously difficult to produce power from pure isolates, but new research reveals that this is no longer an issue. Pure cultures of exolectrogens use to generate current also show a broad substrate utilization spectrum, in line with previous studies.

This paper studies a variant of the C₂/G/1 queue, where the service time distribution for a customer depends on whether the server is busy or idle when the customer arrives. This class of models is relevant in scenarios where the server may require varying amounts of time when it resumes service after being idle. Customer arrives in the system according to 2-stage Coxian distribution. By using supplementary variable techniques and recursive method that utilizes generating function, we derived steady-state probabilities to analyze the distribution of queue length and sojourn time. Queueing models of this type have wide application in streamline operations like waste material management, and ensure effectiveness.

Due to environmentally benign process and a large research area, the green synthesis of metal oxide nanoparticles using plant extracts is a possible replacement for conventional physicochemical synthesis methods. In the present investigation, ferric nitrate (Fe(NO₃₎₃.9H₂O) and pomegranate peel extract are used to prepare iron oxide nanoparticles (α-Fe₂O₃ NPs). These prepared particles are then examined using FTIR spectroscopy, energy-dispersive X-ray (EDX), and scanning electron microscopy (SEM). The results of FTIR reveal distinct peaks in the (450–550 cm⁻¹) range, which are ascribed to the vibration of Fe–O in Fe₂O₃. Prior to this, SEM data demonstrated the shape of iron oxide particles, which has dimensions between 22 and 43 nm and are round and irregular in size.

This research entails a comprehensive assessment involving the measurement of prolyl glycosidase levels and calcium concentrations within a cohort of rats, which are subjected to induce myocardial infarction through subperitoneal injection of physiological solutions following an 18-h fasting period. The experimental rats are meticulously partitioned into five distinct groups to facilitate comparative analysis. The initial group serves as the healthy control, providing a baseline reference, while the fifth group is administered the pharmaceutical agent simvastatin. The intermediary groups are administered varying concentrations of flavonoids, specifically extracted from the rosemary plant utilizing advanced high-performance liquid chromatography (HPLC) technology. This study's design is carefully constructed to discern the impact of these interventions on prolyl glycosidase levels and calcium concentrations in the context of induced myocardial infarction. The administered substances, particularly simvastatin and the varied concentrations of rosemary-derived flavonoids, are strategically chosen to elucidate their potential influences on the measured biochemical parameters. The utilization of advanced HPLC technology for the extraction of flavonoids from rosemary ensures precise and controlled administration of these compounds to the experimental groups. This research design allows for a nuanced exploration of the effects of simvastatin and rosemary-derived flavonoids on prolyl glycosidase levels and calcium concentrations in the context of induced myocardial infarction. The delineation of the impact of these interventions on the measured biochemical markers contributes to a deeper understanding of potential therapeutic implications, paving the way for further investigations and potentially innovative interventions in cardiovascular health.

In the present research article, two small organoselenium molecules, 2-(phenylselanyl)ethanamine, L₁H and 2-(phenylselanyl)propanamine, L₂H, have been synthesized via high yield synthetic route and characterized using elemental, UV–vis, FTIR, (¹H and ⁷⁷Se) NMR, and mass spectrometry along with computational investigation, confirming selenium integration. Density functional theory (DFT) study elucidates the optoelectronic properties and structures of L₁H and L₂H, providing insights into stability and reactivity of selenium bearing small organic compounds. In addition to this, molecular docking studies and pharmacokinetic profile highlights potential binding affinity with target proteins and also suggests their promising bioactivity. The interaction between the regulatory proteins involved in pancreatic ductal adenocarcinoma (PDAC) and the synthesized small molecule L₁H and L₂H shows the involvement of amine group and selenium atom for inhibiting the proteins to potentially stop the growth of cancer cells. The comprehensive investigation lays groundwork for further exploration of these compounds in small molecule drug development and medicinal chemistry.

The state of oxidative stress concomitant with type 2 diabetes mellitus (DM) is recognized as a significant factor leading to impaired glycemic control. This study is designed to elucidate the clinical benefits of employing silver and palladium nanocompounds in addressing oxidative disturbances. The investigation encompasses twenty rabbits aged between 6 to 12 months, divided into four groups, each comprising five rabbits. The first group comprises healthy rabbits, serving as the control group. The second group consists of induced diabetic rabbits left untreated, also serving as a control group. The third and fourth groups encompass induced diabetic rabbits treated with silver nanocompounds at concentrations of 10 000 micrograms/mL and 20 000 µg mL⁻¹, respectively, relative to body weight. A singular daily dose is administered for a duration of two weeks. The study's findings demonstrated the effects of silver nanocompounds in mitigating oxidative disturbances by reducing blood glucose levels and lowering anti-thyroid peroxidase antibodies (anti-TPO), glutathione peroxidase (GSH-Px), and catalase (CAT) levels. These effects are dose-dependent and significantly associated with an observable enhancement in glycemic control.

The research extensively explores the optical, structural, and morphological characteristics of zinc oxide (ZnO) doped with manganese and cobalt nanoparticles, with a specific focus on their impact on photocatalytic activity. ZnO, known for its cost-effectiveness and high efficiency due to a broadband gap (≈3.37 eV), is widely studied as a semiconductor photocatalyst. However, ZnO's intrinsic limitation lies in its predominant photocatalytic activity under UV light irradiation. To address this, transition metal ions (Mn and Co) are introduced to the ZnO lattice to create new energy levels in the band gap. By optimizing the dosage of the Mn-ZnO and Co-ZnO photocatalyst, the work presents a noteworthy impact, contributing to a significant reduction in photodegradation time (≈30 min), demonstrating the enhanced efficiency of the photocatalytic process.

Epoxy is frequently employed as a protective coating to inhibit corrosion. Over the years, researchers have focused on improving the barrier properties of epoxy coatings because prolonged exposure to harsh environments may induce corrosive ion permeation. In this regard, polyaniline functionalized graphene oxide (GO/PANI) nanocomposite is introduced into the epoxy matrix to enhance the barrier performance. GO is first sonicated at 5 h to yield smaller graphene sheet sizes and to ensure uniform suspension. The research reveals that thicker coating with five layers of the nanocomposites (GO/PANI-5) successfully protects mild steel substrates at a corrosion rate (CR) of 0.0037 mm y⁻¹ compared to pure epoxy coating at an equivalent thickness (≈0.016 mm year⁻¹). Detailed investigation of electrochemical impedance spectroscopy (EIS) shows that the GO/PANI-5 coating exhibits higher impedance with four to five orders of magnitude than the pure epoxy and bare mild steel substrate. The significant findings denote that a thicker layer with a smaller GO sheet allows for more barrier characteristics due to stronger adhesion and slower ion diffusion rate. To conclude, incorporating GO/PANI nanocomposites will add more protective values to pure epoxy and provide multifaceted applications regardless of thickness.

Globally, the need of future refrigerant is becoming important to save the environment owing to the increase of urbanization and industrialization. The rate of accumulation of greenhouse gasses (GHG) from refrigerants depends on the rate of increase in urbanization and industrialization. However, the candidature of different classes of refrigerants to the stage of future refrigerants has been hindered by different challenges. Hence, the developments achieved in eliminating the various challenges has been studied through literature and the viability status of those classes of refrigerants has been improvised on the basis of green refrigeration, thermodynamic properties, performances and system design approaches. This paper reviews viability of most recently proposed refrigerants as future refrigerants. Hydrofluoroolefin (HFO) is the most viable class of refrigerants because of improvements noted in the challenges that hinder its future scope. Carbon dioxide (R-744) has also a viable scope of future refrigerants under controlled operating condition. In addition to that for ultra low temperature (ULT) refrigeration system, R-170, R-1132a, and R41 have been considered as most viable refrigerants.