Increment Of Concentration Research Articles

Long-term Exposure to Ambient Air Pollution and its Association with Mental Well-Being, Depression and Anxiety: A Nationally Representative Study.

Exposure to ambient air pollution may play a role in the onset of common mental disorders like depressive and anxiety disorders. The association of long-term exposure to particles smaller than 10 μm (PM10) with these diseases remains unclear. This study aimed to estimate the association of long-term exposure to PM10 with mental well-being and the frequency of probable diagnosis of common mental disorders. A nationally representative cross-sectional study was done in mainland Portugal. Long-term exposure was estimated through one-year average concentrations of PM10, calculated with data from the Portuguese Environment Agency, attributed individually considering individuals' postal codes of residence. The mental well-being and the probable diagnosis of common mental disorders were ascertained through the five-item Mental Health Inventory scale. Linear and Robust Poisson regression models were computed to estimate change percentages, prevalence ratios (PR), and their 95% confidence intervals (95% CI). The median (interquartile range) concentration of PM10 was 18.6 (15.3 - 19.3) μg/m3. The mental well-being score was 72 (56 - 84) points, on a scale from 0 to 100. A probable diagnosis of common mental disorders was found in 22.7% (95% CI: 20.0 to 25.6). Long-term exposure to PM10 was associated with a non-statistically significant decrease in the mental well-being score [for each 10 μg/m³ increment in one-year average PM10 concentrations, there was a 2% (95% CI: -8 to 4) decrease], and with a non-statistically significant increase in the common mental health frequency (PR = 1.012, 95% CI: 0.979 to 1.045). We did not find statistically significant associations between long-term exposure to PM10 and mental well-being or the frequency of probable diagnosis of common mental disorders. These results may be explained by the reduced variability in the exposure values, given the geographical distribution and functioning of the network of air quality monitoring stations. This study contributes with evidence for low levels of air pollutants, being one of the first to adjust for individual and aggregate-level variables. Moreover, to the best of our knowledge, this was the first nationally representative, population-based study conducted on the Portuguese population using real-life data. Maintaining a robust and nationwide air quality monitoring network is essential for obtaining quality exposure data.

Effect of incremental tazobactam concentrations on the bactericidal activity of piperacillin against ESBL-producing enterobacterales clinical isolates causing bacteraemia.

We evaluated the activity of piperacillin in relation to INCREASING TAZOBACTAM CONCENTRATION against ESBL-producing Enterobacterales collected from patients with bacteraemia. Increasing tazobactam concentration (4, 12 or 24mg/L) exerted a reduction of piperacillin MICs under the clinical breakpoint in a concentration-dependent manner (0%, 60% and 90% of clinical isolates). Also, activity of piperacillin/tazobactam based at higher achievable serum concentrations (123/14mg/L) is needed to reduce the bacterial growth in 92% of ESBL-producers. CHANGES IN THE PIPERACILLIN MIC IN RELATION TO INCREASING TAZOBACTAM SUGGEST THAT REALTIME TDM COULD BE USED FOR DRIVEN ANTIMICROBIAL THERAPY WITH PIPERACILLIN/TAZOBACTAM IN BSI DUE TO ESBL STRAINS.

Long-term exposure to ozone and sleep disorders in children: A multicity study in China

Evidence regarding the link between long-term ambient ozone (O3) exposure and childhood sleep disorders is little. This study aims to examine the associations between long-term exposure to O3 and sleep disorders in children. We conducted a population-based cross-sectional survey, including 185,428 children aged 6–18 years in 173 schools across 14 Chinese cities during 2012 and 2018. Parents or guardians completed a checklist using Sleep Disturbance Scale for Children, and O3 exposure at residential and school addresses was estimated using a satellite-based spatiotemporal model. We used generalized linear mixed models to test the associations with adjustment for factors including socio-demographic variables, lifestyle, meteorology and multiple pollutants. Mean concentrations of O3, particulate matter with diameters ≤2.5 mm (PM2.5) and nitrogen dioxide (NO2) were 89.0 μg/m3, 42.5 μg/m3 and 34.4 μg/m3, respectively. O3 and NO2 concentrations were similar among provinces, while PM2.5 concentration varied significantly among provinces. Overall, 19.4% of children had at least one sleep disorder. Long-term exposure to O3 was positively associated with odds of sleep disorders for all subtypes. For example, each interquartile increment in home-school O3 concentrations was associated with a higher odds ratio for global sleep disorder, at 1.22 (95% confidence interval: 1.18, 1.26). Similar associations were observed for sleep disorder subtypes. The associations remained similar after adjustment for PM2.5 and NO2. Moreover, these associations were heterogeneous regionally, with more prominent associations among children residing in southeast region than in northeast and northwest regions in China. We concluded that long-term exposure to O3 is positively associated with risks of childhood sleep disorders. These associations varied by geographical region of China.

Effect of stacking fault energy on hetero-deformation in gradient nanograined Cu-Ni alloys

The stacking fault energy (SFE) effect on nanocrystalline metal deformation mechanisms has been extensively studied from dislocation and grain boundary perspectives. Compared to homogeneous nanocrystalline structures, the gradient nanograined (GNG) structure exhibits varied grain sizes, resulting in different SFE effects across regions during the hetero-deformation process. In this work, molecular dynamics (MD) simulation is conducted on GNG Cu-Ni binary alloys with incremental Ni concentration, to investigate the SFE effect at different deformation stages of the GNG structure. It is revealed that the elastic deformation stage shows a close relationship with alloy intrinsic property (e.g. elastic modulus) from Ni concentration variation, with neglectable SFE effect. Under the hetero-deformation stage, different from the homogeneous polycrystalline counterpart, the effect under high SFE condition is demonstrated from the overall dislocation density decline and the competition between the perfect and partial dislocations in the gradually varied grains across the GNG structure, which finally results in lower strain gradient, geometry necessary dislocation density, and a less effective hetero-deformation process. The active GB sliding and migration are found to offset this dislocation density decline in the sample with the relatively high SFE, which brings in higher GB stress concentration and larger GB free volume of the GNG structure. Besides, the GB relaxation across the GNG structure under the high strain rate tensile loading is also illustrated and discussed. The results further support the essential deformation mechanism underlying heterostructure materials.

Study on the interaction mechanism of whey protein isolate with phosphatidylcholine: By multispectral methods and molecular docking.

The elucidation of the interaction mechanism between phospholipids and milk proteins within emulsions is pivotal for comprehending the properties of infant formula fat globules. In this study, multispectral methods and molecular docking were employed to explore the relationship between phosphatidylcholine (PC) and whey protein isolate (WPI). Observations indicate that the binding constant, alongside thermodynamic parameters, diminishes as temperature ascends, hinting at a predominantly static quenching mechanism. Predominantly, van der Waals forces and hydrogen bonds constitute the core interactions between WPI and PC. This assertion is further substantiated by Fourier transform infrared spectroscopy, which verifies PC's influence on WPI's secondary structure. A detailed assessment of thermodynamic parameters coupled with molecular docking reveals that PC predominantly adheres to specific sites within α-lactalbumin, β-lactoglobulin, and bovine serum albumin, propelled by a synergy of hydrophobic interactions, hydrogen bonding, and van der Waals forces, with binding energies noted at -5.59, -6.71, and -7.85kcal/mol, respectively. An increment in PC concentration is observed to amplify the emulsification properties of WPI whilst concurrently diminishing the zeta potential. This study establishes a theoretical foundation for applying the PC-WPI interaction mechanism in food.

Antibacterial and antibiofilm activities of zingerone and niosomal zingerone against methicillin-resistant Staphylococcus aureus (MRSA).

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Nanoparticles are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections because of the drug concentration increment at the desired location and protection from enzymatic degradation. The goal of this study was to evaluate the effect of the antibacterial and antibiofilm activities of zingerone and niosome containing zingerone against pre-formed biofilm of MRSA isolates. 62 MRSA isolates cultured from patients with diabetic ulcers were investigated. Niosomes were synthesized and characterized by X-ray diffraction, zeta potential and scanning electron microscopy (SEM). The size of niosomal particles measured by SEM and zetasizer. The surface charge of prepared niosomes was about -37 mV. The effect of the zingerone and noisome containing zingerone was evaluated against biofilms of MRSA isolates. Also, the antibiofilm activity of prepared niosomes on gene expression of MRSA biofilms was evaluated using Real Time PCR. Our results demonstrated that the niosome containing zingerone had a diameter of 196.1 nm and a -37.3-mV zeta potential. Zingerone removed one and three-day old biofilms of MRSA at the concentration of 1000 μg/ml, while the zingerone-laoded niosomes removed 1, 3- and 5-days old biofilms at the concentration of 250 μg/ml, 250 μg/ml, and 500 μg/ml. The results indicated that niosome containing zingerone eliminated MRSA and its biofilms faster compared with free zingerone and it suggested that zingerone-encapsulated niosomes could be considered as a promising treatment against MRSA and its biofilms.

Effect of Nb content on the mechanical properties of Nbx(MoTaW)(1-x) (x = 0.4, 0.55, and 0.7) refractory multicomponent alloys

The MoNbTaW refractory multicomponent alloy (RMCA) retains good yield strength up to 1873K, but limited plasticity and high density at room temperature impede its utility in practical applications. Thus, a unique alloy design approach based on composition modification was used to improve these properties. Among the four constituent elements of the MoNbTaW alloy, Nb has good plasticity and lower density; hence a series of alloys with varying Nb content, namely Nbx(MoTaW)(1-x) with x = 0.4, 0.55, and 0.7 (designated as Nb0.4, Nb0.55, and Nb0.7 in this manuscript), were processed using vacuum arc melting. X-ray diffraction results showed that all the alloys formed as single-phase with the body-centered cubic crystal structure. The microstructures of these RMCAs are dendritic in nature with segregation of elements that decreased with heat treatment. The hardness values showed a decrease as the Nb content increased. The compressive yield strength values are 1251, 1055, and 945 MPa, and those of fractured strain are 10, 22, and 33 % for Nb0.4(MoTaW)0.6, Nb0.55(MoTaW)0.45, and Nb0.7(MoTaW)0.3 respectively. The increase in plastic strain and toughness is due to the increment in the Nb concentration, which is directly interpreted as an enhancement in degree of plasticity. The average grain sizes of Nb0.4, Nb0.55, and Nb0.7 RMCAs are measured to be 86 μm, 106 μm and 145 μm respectively. It was observed that 36 % of the grains are above 100 μm for Nb0.4 alloy, whereas this fraction is increased to 49 % and 60 % for Nb0.55 and Nb0.7 alloys respectively, which indicates an increase in average grain size as well as fraction of coarser grains as the Nb content increases. Hence, the improvement in plasticity is attributed to the increase in the average grain size and broader grain distribution. Fracture surface analysis of all the compositions showed quasi-cleavage behavior. This study demonstrates that increasing the Nb concentration in the MoNbTaW RMCA enhances plasticity while decreasing density. In comparison to conventional niobium alloys like C103 and FS-85, the alloys of the present study had higher yield strength at the temperatures where the tests were carried out. The specific yield strength values of these alloys are found to be higher than commercially available Nb alloys.

The synergistic influence of metal cations on the drying and viscosity of linseed oil assessed by means of model samples containing synthesised metal carboxylates

The recent multi-analytical study carried out on the Van Eyck’s Ghent Altarpiece showed the simultaneous presence of several kinds of metal carboxylates in oil-rich glaze layers. This outcome raised the question whether these carboxylates had already formed during the preparation of the oil binder by the artists. In the case of early-stage formation, they may have had an impact on the drying rate of the resulting oil, as well as on its handling properties. This hypothesis was investigated using a model system of in-house-prepared linseed oil containing incremental concentrations (2–5–10 wt.%) of relevant metal carboxylates (i.e. Ca-, Zn-, Cu-, and Pb oleates and stearates). This paper describes the influence of these type of molecules on the drying rate of linseed oil and, to an extent, on its viscosity. The drying time of the linseed oil, to which one or more metal carboxylates were added, was measured with a drying recorder while the viscosity was assessed with a rheometer. When introduced together, some of these metal carboxylates act in synergy to shorten the drying time with respect to the situation when the same metal carboxylates were added separately to linseed oil. Mixtures of Ca- and Zn-oleates proved to have a larger effect than other binary combinations. Addition of two metal oleates (combination of Ca/Zn/Cu/Pb) reduced the drying time even more. On the other hand, specific combinations of three metal stearates and/or oleates also demonstrated a significant synergistic effect towards increasing the viscosity of the binder. Especially combinations of Ca/Zn/Cu and Ca/Zn/Pb stearates and oleates gave rise to the highest level of linseed oil viscosity increase, when compared to the situation in which the same metal carboxylates were added separately.

Air pollution, greenspace exposure and risk of Parkinson's disease: a prospective study of 441,462 participants.

The current understandings of the relationship between air pollution (AP), greenspace exposure and Parkinson's Disease (PD) remain inconclusive. We engaged 441,462 participants from the UK Biobank who were not diagnosed with PD. Utilizing Cox proportional hazard regression model, relationships between AP [nitrogen dioxide (NO2), and nitrogen oxides (NOX), particulate matter < 2.5μm in aerodynamic diameter(PM2.5), coarse particulate matter between 2.5μm and 10μm in aerodynamic diameter(PM2.5-10), particulate matter < 10μm in aerodynamic diameter(PM10)], greenspace exposure, and PD risk were determined independently. Our analyses comprised three models, adjusted for covariates, and affirmed through six sensitivity analyses to bolster the robustness of our findings. Moreover, mediation analysis was deployed to discern the mediating effect of AP between greenspaces and PD. During a median follow-up of 12.23years (5,574,293 person-years), there were 3,293 PD events. Each interquartile (IQR) increment in NO2 and PM10 concentrations were associated with 10% and 8% increase in PD onset risk, while the increases in NOX, PM2.5 and PM2.5-10 were not associated with PD risk. Additionally, greenspace may safeguard by reducing NO2 and PM10 levels, with the effect mediated by NO2 and PM10 in greenspace-PD relationship. Our findings indicate that an IQR increase in ambient NO2 and PM10 concentrations was associated with risk of PD development, while other pollutants (NOX, PM2.5 and PM2.5-10) were not associated with PD risk. Firstly, we find that augmented exposure to greenspace was associated with the lower PD risk by reducing NO2 and PM10 levels.

Alcohol intake and endogenous sex hormones in women: Meta-analysis of cohort studies and Mendelian randomization.

The mechanisms underlying alcohol-induced breast carcinogenesis are not fully understood but may involve hormonal changes. Cross-sectional associations were investigated between self-reported alcohol intake and serum or plasma concentrations of estradiol, estrone, progesterone (in premenopausal women only), testosterone, androstenedione, dehydroepiandrosterone sulfate, and sex hormone binding globulin (SHBG) in 45 431 premenopausal and 173 476 postmenopausal women. Multivariable linear regression was performed separately for UK Biobank, European Prospective Investigation into Cancer and Nutrition, and Endogenous Hormones and Breast Cancer Collaborative Group, and meta-analyzed the results. For testosterone and SHBG, we also conducted Mendelian randomization and colocalization using the ADH1B (alcohol dehydrogenase 1B) variant (rs1229984). Alcohol intake was positively, though weakly, associated with all hormones (except progesterone in premenopausal women), with increments in concentrations per 10 g/day increment in alcohol intake ranging from 1.7% for luteal estradiol to 6.6% for postmenopausal dehydroepiandrosterone sulfate. There was an inverse association of alcohol with SHBG in postmenopausal women but a small positive association in premenopausal women. Two-sample randomization identified positive associations of alcohol intake with total testosterone (difference per 10 g/day increment: 4.1%; 95% CI, 0.6-7.6) and free testosterone (7.8%; 4.1-11.5), and an inverse association with SHBG (-8.1%; -11.3% to -4.9%). Colocalization suggested a shared causal locus at ADH1B between alcohol intake and higher free testosterone and lower SHBG (posterior probability for H4, 0.81 and 0.97, respectively). Alcohol intake was associated with small increases in sex hormone concentrations, including bioavailable fractions, which may contribute to its effect on breast cancer risk.

Evaluation of Heat Transfer and Fluid Dynamics across a Backward Facing Step for Mobile Cooling Applications Utilizing CNT Nanofluid in Laminar Conditions

In a variety of engineering applications, the efficacy of heat dissipation in mobile cooling systems is greatly influenced by the Backward Facing Step. Its significance in optimizing cooling solutions for mobile devices is highlighted by the fact that its design and fluid dynamics are crucial in minimizing skin friction and improving passive heat transfer. In this paper, we present a verification of an advanced numerical model for heat transfer and fluid flow through a Backward Facing Step, used in mobile cooling. The objective of this study is to explore fluid separation, a method enhancing passive heat transfer and reducing skin friction. ANSYS/FLUENT software has been used to solve the backward facing step in a horizontal duct filled with pure water. Carbon nanotube (CNT) dispresed into the base fluid at different volume fractions of 0.2%, 0.65%, and 1%. This study focused on laminar flow conditions ranging from Reynolds numbers 200 to 900. In order to reduce the computation time and ensuring the accuracy and reliability of numerical simulations, a grid independence study has been conducted. The findings revealed a substantial rise in the average Nusselt number and heat transfer coefficient with increased Reynolds number and volume fraction of nanoparticles. Specifically, the nanofluid (CNT/water) exhibited the highest average Nusselt number and heat transfer coefficient with volume fractions 1%. Furthermore, the research showed a decrease in the skin friction factor as both Reynolds number increased and nanoparticles’ volume fraction decreased. The increments of nanoparticles' concentrations lead to increase viscosity, promotes agglomeration, alters flow behaviour by inducing turbulence, and enhances heat transfer. These factors collectively contribute to higher skin friction due to increased resistance to fluid flow and disrupted streamline patterns

Real-Time Potentiometric Monitoring of Tetrachloroaurate(III) with an Ion-Selective Electrode and Its Applications to HAuCl4 Iodide-Catalyzed Reduction by Hydroxylamine

Ion-selective electrodes for tetrachloroaurate(III) have been developed for potentiometric monitoring of the reduction reaction of tetrachloroaurate(III). Three different plasticized polyvinyl chloride membranes containing tridodecymethylammonium chloride as an anion exchanger were investigated. These membranes differ in the plasticizer used, either 2-nitrophenyl octyl ether (NPOE) or tricresyl phosphate (TCP) or bis-(2-ethylhexyl) sebacate (DOS). The potentiometric response of the electrodes to the tetrachloroaurate(III) concentration was studied by two methods. In the first method, commonly used in the calibration of ion-selective electrodes, successive tetrachloroaurate(III) concentration increments were used and the potential was allowed to stabilize after each concentration step. The second method was developed to mimic the tetrachloroaurate(III) reduction reaction in which there is a continuous decrease in the concentration of tetrachloroaurate(III). This was achieved by continuously diluting an initial concentration of tetrachloroaurate(III) by pumping a diluent solution while keeping the sample volume constant. This method gave an excellent linear response to the tetrachloroaurate(III) concentration. The calibrated electrodes were used for the potentiometric monitoring of the kinetics of a newly observed reaction: the reduction of tetrachloroaurate(III) by hydroxylamine catalyzed by iodide. A mechanism for this reaction is proposed on the basis of the experimental results obtained.

Cytotoxic, antioxidant, antibacterial activity of phytochemicals from Phragmanthera austroarabica.

The cytotoxic, antioxidant, anticancer, and antibacterial properties of ethanolic extracts from Phragmanthera austroarabica is of interest. Plants of P. austroarabica were gathered from the southern Saudi Arabian region of Albaha. P. austroarabica extract was assessed using DPPH (2, 2-diphenyl-1-picrylhydrazyl). The German Collection of Microorganisms and Cell Cultures (DSMZ) cancer cell lines used in this investigation. The cytotoxic activity of P. austroarabica extract was explored against MCF-7 breast and A549 lung cancer cell lines, along with doxorubicin as a positive control. In both treated cells, P. austroarabica showed a remarkable activity via suppressing the cell's survival. In terms of IC50 (concentration equivalent to a survival rate of 50%), MCF-7 breast cancer cells were more sensitive to P. austroarabica extract.) DPPH colorimetric assay was employed to assess the antioxidant properties of P. austroarabica extract, the antioxidant activity was increased along with increment of extract concentrations. The leaves aqueous extract of P. austroarabica inhibited the growth of S. aureus by 6.3±0.12 mm and 24±0.43 mm and 15±0.56 mm respectively for seed, leaf and stem at concentrations 50 µl. However, the same concentrations inhibited the growth of E. coli by 25±0.75, 0.00 mm and 24±0.18 mm, following the same order. Different superscript letters indicate means that are significantly different at level (p<0.05). Minimal inhibitory concentrations (MIC) of P. austroarabica ethanolic extracts against the tested microorganisms were 1.5, 1.6 and 1.5, respectively for seed, leaf and stem against Staph. Aureus and were 1.2, 0.00 and 1.2, respectively for seed, leaf and stem against E. coli.

Improved photocatalytic activity of (Ni, Mn) co-doped ZnO nanoparticles prepared via green synthesis route using orange peel extract

(Ni–Mn) co-doped ZnO nanoparticles were synthesized for different doping concentrations (1 %, 2 %, and 3 %) and compared with the purely synthesized ZnO nanoparticles. Green synthesis route was followed to fabricate both pure and co-doped ZnO nanoparticles and the orange peel extract was used as the reducing agent. The main objectives of this research were to reduce the use of toxic chemicals and develop an eco-friendly green route for both pure and doped ZnO nanoparticle synthesis. Additionally, the co-doping effect on the photocatalytic activity was also observed. The synthesized particles were extensively characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) analysis, Fourier Transform Infrared spectroscopy (FTIR), and Ultraviolet–visible (UV–vis) spectroscopy. XRD analysis confirmed the exitance of ZnO nanoparticles with wurtzite structure. No extra peaks were found for the co-doped sample confirming the successful doping. The crystallite size decreased after doping and the range varied from 36 nm to 35 nm with increasing doping concentration. SEM analysis revealed the average particle size ranging from 66.42 nm to 37.52 nm with increasing doping concentration, the particle was irregular in shape, and agglomeration was observed. The FTIR data unveiled the existence of Ni–O, Mn–O, and Zn–O bands in the synthesized materials. The band gap of the NPs was determined from the UV–Visible spectroscopy analysis which varied from 3.30 eV to 2.71 eV with increasing doping concentration. The photocatalytic activity significantly improved with the increment of the doping concentration. The 2 % and 3 % doped samples degraded almost 97 % of the methylene blue dye at 30 min.

DNA-damage RBE assessment for combined boron and gadolinium neutron capture therapy.

Neutron capture therapy (NCT) by 10B and 157Gd agents is a unique irradiation-based method which can be used to treat brain tumors. Current study aims to quantitatively evaluate the relative biological effectiveness (RBE) and dose distributions during the combined BNCT and GdNCT modalities through a hybrid Monte Carlo (MC) simulation approach. Snyder head phantom as well as a cubic hypothetical tumor was at first modeled by Geant4 MC Code. Then, the energy spectra and dose distribution relevant to the released secondary particles during the combined Gd/BNCT were scored for different concentrations of 157Gd and 10B inside tumor volume. Finally, the scored energy spectra were imported to the MCDS code to estimate both RBESSB and RBEDSB values for different 157Gd concentrations. The results showed that combined Gd/BNCT increases the fluence-averaged RBESSB values by about 1.7 times when 157Gd concentration increments from 0 to 2000µg/g for both considered cell oxygen levels (pO2=10% and 100%). Besides, a reduction of about 26% was found for fluence-averaged RBEDSB values with an increment of 157Gd concentration in tumor volume. From the results, it can be concluded that combined Gd/BNCT technique can improve tumor coverage with higher dose levels but in the expense of RBEDSB reduction which can affect the clinical efficacy of the NCT technique.

Study of the cationic substitution effect on the magnetic properties of the ferrite MnxZn1-xFe2O4 nanoparticles prepared by TREG-mediated solvothermal route

MnxZn1-xFe2O4 (x = 0–1) solid solution was prepared using the TREG-mediated solvothermal method. 10–12 nm spherical superparamagnetic particles (except for ZnFe2O4) were obtained. At room temperature, the ferrites have lower magnetic saturation (Ms) than magnetite. However, at 10 K, it is precisely the opposite. DRX and EXAFS showed that incorporating Zn2+ ions in tetrahedral A-sites provokes a redistribution of Mn and Fe ions in octahedral B-sites of the mixed spinel structure. For Zn concentrations from x = 0.5 and below, the Mn and Fe ions are almost equally distributed between A and B-sites. Therefore, at low Zn concentrations, the small migration of Fe and Mn ions to B-sites increases the magnetic moment of B sub-lattices and, consequently, the total magnetic saturation. In addition, Mn2+ oxidized to Mn3+ and, simultaneously, Fe3+ reduced to Fe2+, affecting the magnetic properties. The increment of Zn concentration severely reduces the magnetization.

Evaluating the biomolecular interaction between delamanid/formulations and human serum albumin by fluorescence, CD spectroscopy and SPR: Effects on protein conformation, kinetic and thermodynamic parameters

Delamanid is an anti-tuberculosis drug used for the treatment of drug-resistant tuberculosis. Since delamanid has a high protein bound potential, even patients with low albumin levels should experience high and rapid delamanid clearance. However, the interaction between delamanid and albumin should be better controlled to optimize drug efficacy. This study was designed to evaluate the binding characteristics of delamanid to human serum albumin (HSA) using various methods: fluorescence spectroscopy, circular dichroism (CD), surface plasmon resonance (SPR), and molecular docking simulation. The fluorescence emission band without any shift indicated the interaction was not affected by the polarity of the fluorophore microenvironment. The reduction of fluorescence intensity at 344 nm was proportional to the increment of delamanid concentration as a fluorescence quencher. UV-absorbance measurement at the maximum wavelength (λmax, 280 nm) was evaluated using inner filter effect correction. The HSA conformation change was explained by the intermolecular energy transfer between delamanid and HSA during complex formation. The study, which was conducted at temperatures of 298 K, 303 K, and 310 K, revealed a static quenching mechanism that correlated with a decreased of bimolecular quenching rate constant (kq) and binding constant (Ka) at increased temperatures. The Ka was 1.75–3.16 × 104 M−1 with a specific binding site with stoichiometry 1:1. The negative enthalpy change, negative entropy change, and negative Gibbs free energy change demonstrated an exothermic-spontaneous reaction while van der Waals forces and hydrogen bonds played a vital role in the binding. The molecular displacement approach and molecular docking confirmed that the binding occurred mainly in subdomain IIA, which is a hydrophobic pocket of HSA, with a theoretical binding free energy of −9.33 kcal/mol. SPR exhibited a real time negative sensorgram that resulted from deviation of the reflex angle due to ligand delamanid-HSA complex forming. The binding occurred spontaneously after delamanid was presented to the HSA surface. The SPR mathematical fitting model revealed that the association rate constant (kon) was 2.62 × 108 s−1M−1 and the dissociation rate constant (koff) was 5.65 × 10−3 s−1. The complexes were performed with an association constant (KA) of 4.64 × 1010 M−1 and the dissociation constant (KD) of 2.15 × 10−11 M. The binding constant indicated high binding affinity and high stability of the complex in an equilibrium. Modified CD spectra revealed that conformation of the HSA structure was altered by the presence of delamanid during preparation of the proliposomes that led to the reduction of secondary structure stabilization. This was indicated by the percentage decrease of α-helix. These findings are beneficial to understanding delamanid-HSA binding characteristics as well as the drug administration regimen.

In vitro Propagation of Singgalang Cabbage (Brassica oleracea var. capitata L.) on Murashige and Skoog Modification Media for Preservation Purpose

Singgalang Cabbage is one of the local cabbage cultivated on the foothills of Mount Singgalang, West Sumatra. Recently, the existence of this cabbage has decreased, so conservation and preservation efforts need to be carried out. This research was conducted to develop method for in vitro propagation and preservation of singgalang cabbage. The Murashige and Skoog (MS) were used as basal media with two experimental stages, i.e., shoot initiation with 6-Benzylaminopurine (BAP), and root induction and plantlet preservation with modification of MS media. The nodal and shoots were used as explants. The results showed that increment of BAP concentrations gave a significant effect on shoot initiation after 60 days of treatment. MS media-enriched with BAP 2 mg/L gave significant increment of shoots (4 shoots/nodus) and leaves (11.67) numbers when compared to other treatments. For root induction and plantlet preservation, it was found that the earlier of root formation was observed in modification of MS media at ½ and ¼ strength. Meanwhile, MS media at ⅛ strength was observed to be better media for plant height increment (4.75 cm) when compared to other treatments. It was found that the plantlets survived and grew well after 120 days under in vitro condition.

Laser flash technique as an efficacious assessment approach for thermal conductivity of tungsten disulphide nanofluids

Two-dimensional tungsten disulphide (WS2) dispersed oil-based nanofluids are prepared by a two-step process and their stability and thermal properties are assessed. UV–visible spectrophotometry reveals marginal loss in relative absorbance over 15 days ensuring dispersion stability of the nano-additives. Thermal diffusivity of nanofluids is measured using the laser flash analyzer while specific heat capacity is studied by differential scanning calorimetry. The thermal diffusivity coupled with the specific heat capacity of the nanofluids provides an estimate of the thermal conductivity of the prepared nanofluids. Specific heat of the nanofluids is observed to increase with temperature and reduce with an increase in the concentration of the nano-additives. A statistical model is developed to predict the influence of density and temperature on the specific heat of the nanofluids. Higher thermal conductivity in comparison to the base fluid is observed which further enhances with an increment in concentration of the nano-additive. The parameters such as concentration of dispersoid and temperature reveal the effect on the thermal conductivity at elevated temperatures. Enhancement in thermal conductivity is observed between 3–12 % which is validated with an analytical model for thermal conductivity of composite nanofluids.

Tailoring the functional properties of LSMO-BTO nanocomposites: A sol-gel synthesis approach and comprehensive characterization

In this study, the sol-gel synthesis technique was harnessed to craft nanocomposites of (1-x)La0.7Sr0.3MnO3-(x)BTO with x values of 0.4, 0.6, and 0.8. The attributes of these meticulously engineered materials were exhaustively explored using a diverse suite of characterization methods. X-ray diffraction analysis irrefutably confirmed the phase purity of the perovskite structure, emphasizing the synthesis's precision. Furthermore, Diffuse Reflectance Spectroscopy shed light on the optical properties of the nanocomposites, revealing a significant shift in bandgap energy that correlated directly with the BTO concentration. Specifically, an increment in BTO concentration resulted in a systematic expansion of the bandgap from 1.51 eV to 1.44 eV. For an in-depth analysis of the magnetic characteristics of the composites, Vibrating Sample Magnetometry was utilized. The magnetic analysis identified a conspicuous reduction in saturation magnetization, highlighting the complex interplay between the composite components at the nanoscale. Additionally, the dielectric properties were rigorously investigated through dielectric measurements, which unveiled a notable increase in the dielectric constant, accompanied by the emergence of novel relaxation behaviors. This finding indicates that adjusting the BTO content within the nanocomposites not only modifies their dielectric properties but also provides a method for fine-tuning their functional performance.