Hasil untuk "Analytical chemistry"

Karaaslan Melek, Gokdere Nuran, Ozturk Batuhan et al.

Apple is one of the four most produced fruits in the world. The remaining pulp from production accounts for over 25 % of the processed fruit. Apple pulp and peel contain phenolic compounds such as flavonoids and flavonoid glycosides, making them a potential candidate for green nanoparticle synthesis. Green synthesis refers to the production of nanoparticles through a process that utilizes a natural molecule and metal salts as reducing agents. In this study, metal nanoparticles were synthesized using an extract prepared from apple pomace waste via green synthesis. The synthesized nanoparticles were characterized using UV–visible spectroscopy, Raman, optical microscopy, energy-dispersive X-ray, atomic force microscopy, and scanning electron microscope. The antibacterial, antibiofilm, antiquorum sensing, and anticancer activities of the synthesized nanoparticles were then investigated. According to the antibacterial activity results, the best activity was seen with silver nanoparticles against Staphylococcus epidermidis ATCC 12228 with 15.625 μg/mL. Similarly, the best antibiofilm activity was seen with silver nanoparticles. However, significant biofilm inhibition was seen with zinc nanoparticles, tin nanoparticles, and cobalt nanoparticles at higher concentrations. Anticancer activity was studied in six different cell lines: HCT-116 and SW480 colon cancer cell lines, A549 and H1975 lung cancer cell lines, and A2780 and OVCAR3 ovarian cancer cell lines. The best activity was shown with nickel nanoparticles.

Nidhi Chauhan, Nishtha Sah, Kirti Saxena et al.

Water is the basis of life on Earth, but due to increased pollution and habitat degradation, water scarcity is increasing day by day. Therefore, it is necessary to detect water pollutants to save water and aquatic diversity. Monitoring of toxic elements present in wastewater effluents is an important factor for further treatment to make it pollutant-free. While various methods have been developed for monitoring these toxic elements, biosensors can overcome the limitations of traditional methods. Biosensors are highly sensitive, selective, low in cost, and simple to use. In this review, we have provided an overview of reported biosensors for the detection of various types of toxic elements that cause water toxicity. A summary of these toxic elements has also been discussed herein. This review aims to provide an overview of advances in biosensing technology used for water monitoring.

Yunlong Li, Nida El Islem Guissi, Junming Dong et al.

Zhongcheng Ke, Xiaoling Cheng, Manting Zhao et al.

To study the reflux extraction process of total flavonoids from loquat leaves and to investigate its protective effect on H9C2 cells in hypoxia injury. An orthogonal test was utilized to optimize the reflux extraction process parameters, Na2S2O4 was used to induce myocardial cell hypoxia injury, MTT assay was used to evaluate cell survival rate, CK, LDH, SOD, MDA were used to evaluate the hypoxia injury of H9C2 cells. The optimized process condition for reflux extraction was 10 times the amount of 70% ethanol for 3 times, each time for 2 h. The extracted content of TFL was 37.12 mg/g under this condition, and the TFL was found to increase cell survival rate, decrease the levels of CK, LDH, MDA, and improve SOD levels. The favored reflux extraction process of loquat leaves is stable and feasible, and the TFL have a good protective effect on H9C2 cells in hypoxia injury.

Claudia Colasante, Jiangping Chen, Vannuruswamy Garikapati et al.

Peroxisomal biogenesis defects frequently trigger processes of remodeling, increased oxidative stress and metabolic dysregulations that cause cellular dysfunction. Despite extensive research into cardiomyocyte ultrastructure and metabolism, knowledge on peroxisomal function in these cells is scarce. The objective of this study was therefore to investigate the impact of the purportedly asymptomatic (mild) deficiency of the peroxisomal biogenesis protein PEX11a on cardiomyocyte structure and cardiac function in mice. Langendorff-reperfusion experiments revealed diminished post-ischemic recovery following <i>Pex11a</i> knockout suggesting compromised cardiac response to ischemic stress. The suboptimal recovery might be attributable to increased ischemia-induced tissue deterioration consequent to morphological and metabolic abnormalities of the cardiomyocytes. Indeed, several alterations were observed in these cells in <i>Pex11a</i> knockout mice: (i) augmented size and number of peroxisomes and lipid droplets; (ii) increased sarcomere length; (iii) altered gene expression of peroxisome proliferator-activated receptors, organellar fission machinery proteins and cardiac markers; and (iv) a lipid composition shift. We hypothesized that peroxisomes contribute to the preservation of cardiomyocyte structure and functionality under conditions of ischemia–reperfusion. We further proposed that even “mild”, undiagnosed peroxisomal defects can significantly impact cardiac performance following ischemia. This poses novel challenges for the risk assessment of cardiac pathologies.

Huamin Li, Ying Zhang, Haidi Wu et al.

Abstract It is highly desirable but still remains challenging to develop high‐performance hydrogels with satisfactory mechanical properties for tissue engineering. Here, anisotropic yet transparent hydrogels (AHs) are prepared for tendon repair via a facile “poor solvent evaporation assisted hot‐stretching” strategy. AHs have great mechanical properties with tensile strength, toughness, and fracture energy as high as 33.14 ± 2.05 MPa, 44.1 ± 3.5 MJ m−3, and 106.18 ± 7.2 kJ m−2, respectively. Especially, AHs show unique flaw‐insensitive characteristics, and cracks can only deflect along the fiber alignment direction rather than propagate transverse to this direction, showing an interesting self‐protection function. The high strength, toughness, and fatigue resistance originate from the hierarchal structure of AHs, i.e., the densified polymeric network comprising fiber bundles and nanofibrils with aligned macromolecular chains, crystalline domains, and intermolecular hydrogen bonds. AHs with superior biocompatibility and swelling resistance can be used to repair rat tendons, and implantation of AHs can promote collagen regeneration for the tendon repair. This study provides a new method to fabricate strong and anti‐fatigue hydrogels as a new class of promising materials for soft tissues.

Remo Ruffini, Yu Wang

Both the Galactic Center and little red dots (LRDs) host million-solar-mass black holes within dense, cold reservoirs of molecules associated with dust grains, and are electromagnetically tranquil. These conditions enable complex molecular chemistry and may serve as natural laboratories for prebiotic genetic evolution by allowing the synthesis of organic molecules essential for life.

Takashi Shimonishi, Kei E. I. Tanaka, Yichen Zhang et al.

The Large Magellanic Cloud (LMC) provides a key laboratory for exploring the diversity of star formation and interstellar chemistry under subsolar metallicity conditions. We present the results of a hot core survey toward 30 massive protostellar objects in the LMC using the Atacama Large Millimeter/submillimeter Array (ALMA) at 350 GHz. Continuum imaging reveals 36 compact sources in total, among which line analyses identify 9 hot cores and 1 hot-core candidate, including two newly identified sources. We detect CO, HCO+, H13CO+, HC15N, HC3N, SiO, SO, SO+, NS, SO2, 34SO2, 33SO2, CH3OH, 13CH3OH, HCOOH, HCOOCH3, CH3OCH3, C2H5OH, H2CCO (tentative), and hydrogen recombination lines from hot cores. CH3OCH3, a complex organic molecule larger than CH3OH, is detected for the first time in a hot core outside the LMC bar region. All hot cores show stronger emission in the high-excitation SO line compared to non-hot-core sources, suggesting that its strong detection will be useful for identifying hot-core candidates in the LMC. Chemical analysis reveals a spread of more than two orders of magnitude in CH3OH abundances, with some sources deficient in COMs. In contrast, SO2 is detected in all hot cores, and its abundance shows a good correlation with rotational temperature. The hot cores without CH3OH detections are all located outside the LMC bar region and are characterized by either high luminosity or active star formation in their surroundings. A combination of locally low metallicity, active star formation in the vicinity, and high protostellar luminosity may jointly trigger the COM-poor hot core chemistry observed in the LMC.

Ananthu Shanmughan, Karuppaiya Balamurugan, Giriraj Kalaiarasi et al.

Hubert H. Kerschbaum, Christopher Gerner, Karin Oberascher et al.

Abstract Lipid-containing vacuoles in microglia were discovered more than one hundred years ago in the brain of patients showing neurodegenerative processes. Recently, molecular-biological studies demonstrated specific changes in lipid-metabolism related to neurodegeneration. Despite that already Alzheimer described a distinct glia phenotype having large, lipid-containing vacuoles (Gitterzellen), little is known about how microglia convert lipid metabolites into a vacuolated phenotype. We studied the impact of liver-derived, insoluble, lipid-enriched nanoparticles (Lef-NP) ( ~ 20 nm) and of ceramide-coated Percoll-nanoparticles (Cer-NP) ( ~ 20 nm) on vacuolization in microglia. Lipidomic analysis of Lef-NP revealed numerous distinct lipids, including pro-inflammatory ceramides, which are enriched in the brain of Alzheimer patients. Video microscopy revealed that hepatocyte-derived Lef-NP and Cer-NP enhanced macropinocytosis, followed by macropinosome swelling and formation of the Gitterzellen phenotype. Neither ceramide nor Percoll-nanoparticles induced Gitterzellen-formation. Electron-tomography visualized membrane contact-sites between nanoparticle-loaded endosomes, endoplasmic reticulum cisternae and mitochondria. Suppression of lipid-nanoparticle-induced Gitterzellen-formation by amiloride, which supresses macropinocytosis, and bafilomycin A, an endosomal acidification inhibitor, further confirmed a pinocytotic pathway in Gitterzellen-formation. Bafilomycin A also reversed Gitterzellen to a ramified microglia phenotype. Our experimental findings suggest that lipid-nanoparticles but not emulsified lipids provoke vacuolization in microglia, and provide a simple in-vitro model for a pathogenic process taking years in the human brain.

Lingting Huang, Dianping Tang, Zhen Yang

Abstract Biomarker identification is a tried‐and‐true method that can provide precise biological information for disease diagnosis. Prompt diagnosis, disease progression monitoring, therapy efficacy evaluation, and prognosis assessment of cancers all benefit from sensitive, rapid, and precise measurement of significant biomarkers employing chemical and immunological approaches. The study of biomolecules and immunoassay evaluations can profit greatly from recent advancements in flexible electronic materials and technologies, which provide amazing flexibility, affordability, mobility, and integration. However, an overview of the implementation of portable immunoassays in conjunction with flexible electronic devices is rare to come by. This review focuses on recent breakthroughs in flexible electronic materials and devices for portable biomarker testing, which provides an extensive summary of flexible electrical components and sensing‐capable devices, emphasizing their adaptability in the construction of biosensing platforms. These platforms employ various signal transduction systems to record biological affinity recognition events, including pressure, temperature, electrical parameters, colorimetric signals, and other physical features. The challenges for portable, integrated, intelligent, and multifunctional immunoassays based on flexible sensing devices are also discussed. The portable immunoassays with flexible electronics would unlock the potential to transform clinical diagnostics into non‐clinical personalized treatments and achieve home‐based point‐of‐care testing for daily monitoring.

Etienne Granet, Khaldoon Ghanem, Henrik Dreyer

Despite its simplicity and strong theoretical guarantees, adiabatic state preparation has received considerably less interest than variational approaches for the preparation of low-energy electronic structure states. Two major reasons for this are the large number of gates required for Trotterising time-dependent electronic structure Hamiltonians, as well as discretisation errors heating the state. We show that a recently proposed randomized algorithm, which implements exact adiabatic evolution without heating and with far fewer gates than Trotterisation, can overcome this problem. We develop three methods for measuring the energy of the prepared state in an efficient and noise-resilient manner, yielding chemically accurate results on a 4-qubit molecule in the presence of realistic gate noise, without the need for error mitigation. These findings suggest that adiabatic approaches to state preparation could play a key role in quantum chemistry simulations both in the era of noisy as well as error-corrected quantum computers.

Boris Bačić, Claudiu Vasile, Chengwei Feng et al.

The purpose of this paper is to contribute towards the near-future privacy-preserving big data analytical healthcare platforms, capable of processing streamed or uploaded timeseries data or videos from patients. The experimental work includes a real-life knee rehabilitation video dataset capturing a set of exercises from simple and personalised to more general and challenging movements aimed for returning to sport. To convert video from mobile into privacy-preserving diagnostic timeseries data, we employed Google MediaPipe pose estimation. The developed proof-of-concept algorithms can augment knee exercise videos by overlaying the patient with stick figure elements while updating generated timeseries plot with knee angle estimation streamed as CSV file format. For patients and physiotherapists, video with side-to-side timeseries visually indicating potential issues such as excessive knee flexion or unstable knee movements or stick figure overlay errors is possible by setting a-priori knee-angle parameters. To address adherence to rehabilitation programme and quantify exercise sets and repetitions, our adaptive algorithm can correctly identify (91.67%-100%) of all exercises from side- and front-view videos. Transparent algorithm design for adaptive visual analysis of various knee exercise patterns contributes towards the interpretable AI and will inform near-future privacy-preserving, non-vendor locking, open-source developments for both end-user computing devices and as on-premises non-proprietary cloud platforms that can be deployed within the national healthcare system.

Tian-Yu Tu, Yang Chen, Ping Zhou et al.

Supernova remnants (SNRs) exert strong influence on the physics and chemistry of the nearby molecular clouds (MCs) through shock waves and the cosmic rays (CRs) they accelerate. To investigate the SNR-cloud interaction in the prototype interacting SNR W28 (G6.4$-$0.1), we present new observations of $\rm HCO^+$, HCN and HNC $J=1\text{--}0$ lines, supplemented by archival data of CO isotopes, $\rm N_2H^+$ and $\rm H^{13}CO^+$. We compare the spatial distribution and spectral line profiles of different molecular species. Using local thermodynatic equilibrium (LTE) assumption, we obtain an abundance ratio $N({\rm HCO^+})/N({\rm CO})\sim10^{-4}$ in the northeastern shocked cloud, which is higher by an order of magnitude than the values in unshocked clouds. This can be accounted for by the chemistry jointly induced by shock and CRs, with the physical parameters previously obtained from observations: preshock density $n_{\rm H}\sim 2\times 10^{5}\rm \ cm^{-3}$, CR ionization rate $ζ=2.5\times 10^{-15} \rm \ s^{-1}$ and shock velocity $V_{\rm s}=15\text{--}20\rm \ km\ s^{-1}$. Towards a point outside the northeastern boundary of W28 with known high CR ionization rate, we estimate the abundance ratio $ N({\rm HCO^+})/N({\rm N_2H^+}) \approx 0.6\text{--}3.3$, which can be reproduced by a chemical simulation if a high density $n_{\rm H}\sim 2\times 10^5 \ \rm cm^{-3}$ is adopted.

Paula Nabais, Jane Malcolm-Davies, Maria João Melo et al.

Abstract The knitted cap was the ubiquitous and most visible garment men wore throughout early modern society, from apprentices to royals. Documentary evidence also suggests that red was a conventional color for specific garments in the sixteenth century, including knitted caps. However, most knitted caps in museum collections are now a muddy brown characteristic of archaeological textiles, and their original color has seldom been studied. Considering the potential of microspectrofluorimetry for analyzing dyes in ancient textiles and manuscript illuminations, this technique was tested on six caps dating from the fifteenth to sixteenth centuries examined in the Knitting in Early Modern Europe research project. The colors are in good preservation condition in two samples, whereas the others show extensive degradation. The emission and excitation spectra acquired allowed the identification of the similarities and differences between samples, grouping them into different dye sources such as cochineal-based and madder-based (RED1 and RED2, respectively). For the coif cap and split-brimmed cap in good condition, analysis through HPLC–MS confirmed the sources of the dyes as Rubia tinctorum and cochineal. It also disclosed the source for another coif cap as Kermes vermilio (RED4). The other knitted items are possibly madder-based (RED3), but HPLC–MS did not allow confirmation of the madder source. The continuing development of a database of excitation and emission spectra acquired from historical textiles, such as the knitted caps, will support the identification of dye sources and specific formulations. Although this technique demands a comprehensive database of references for comparison with the complex signals identified, it allows for rapid spectra acquisition, providing tremendously valuable information.