Hasil untuk "Analytical chemistry"

F. J. Stevenson

J. Dean

R. Gibbs

S. Armenta, S. Garrigues, M. Guardia

T. Ozer, Cathleen J. McMahon, C. Henry

Microfluidic paper-based analytical devices (μPADs) are the newest generation of lab-on-a-chip devices and have made significant strides in both our understanding of fundamental behavior and performance characteristics and expanding their applications. μPADs have become useful analytical techniques for environmental analysis in addition to their more common application as medical point-of-care devices. Although the most common method for device fabrication is wax printing, numerous other techniques exist and have helped address factors ranging from solvent compatibility to improved device function. This review highlights recent reports of fabrication and design, modes of detection, and broad applications of μPADs. Such advances have enabled μPADs to be used in field and laboratory studies to address critical needs in fast, cheaper measurement technologies. Expected final online publication date for the Annual Review of Analytical Chemistry, Volume 13 is June 12, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

M. Sajid, J. Płotka-Wasylka

Abstract Nanoparticles (NPs) are widely employed in different research areas, ranging from analytical chemistry and environmental science to medicine, the agriculture and pharmaceutical industry. This is mainly due to the unique characteristics of NPs and the novelty they introduce in such applications. In analytical chemistry, the role of NPs can differ depending on the nature of the steps involved in analytical process. NPs are probably most useful for detection, but sample preparation has also profited from them. For instance, NPs can advantageously replace conventional sorbents for solid-phase extraction. Moreover, NPs are being increasingly used as stationary phases in gas and liquid chromatography or electrochromatography. In this review, a brief summary on the classification, synthesis methods, and properties of NPs is given. Moreover, the examples of applications in different research area are shortly presented. However, the merits of this work are to present the use of NPs in analytical chemistry field.

Yogalakshmi Vadivelu, Aishwarya Sendrayal Raj, Rajkumar Muniyandi et al.

We describe a facile and efficient chemical activation technique for the synthesis of activated graphene-modified electrodes able to perform simultaneous and specific identification of uric acid (UA) and dopamine (DA) biomolecules. To find out suitable agent for this specific electrocatalytic application, we have used three chemicals, namely potassium hydroxide, zinc chloride, and phosphoric acid that have been tested. Cyclic voltammogram (CV), linear sweep voltammogram (LSV), differential pulse voltammogram (DPV), electrochemical impedance spectroscopy (EIS) measurements, field emission scanning electrochemical microscopy (FESEM), and transmission electron microscopy (TEM) techniques are performed to analyze the activated graphene-modified electrodes being utilized as an electrochemical sensor, it can effectively detect dopamine and uric acid simultaneously in the existence of ascorbic acid. The KOH-activated graphene (AGK) exhibits a high electrocatalytic activity towards selectively detecting dopamine and uric acid. In the DPV and LSV studies, the peak gap between dopamine (DA) and uric acid (UA) reaches a maximum of 0.23 V. The calibration curves were calculated, with detection limits of 1.96 µM for DA and 1.97 µM for UA in LSV, and 0.09 µM for DA and 0.19 µM for UA in DPV, respectively. The ranges of the calibration curves are 2–380 µM for LSV and 0.02–400 µM for DPV. The presented AGK-modified screen-printed carbon electrode has been effectively operated to efficiently detect DA and UA selectively and simultaneously in real-time samples performed with acceptable results.

Tiange Gu, Jingyi Sun, Saiting Wang et al.

Characterization of tea volatile substances is important for tea quality assessment, flavor evaluation, and manufacturing process control. In this work, an online monitoring system was developed and directly coupled with soft ionization by chemical reaction in transfer (SICRIT) ion source. Tea samples were roasted online at 160 °C, and the generated vapors were transferred to the SICRIT source for real-time ionization and high-resolution mass spectrometry (MS) detection. The results showed progressive release of numerous volatile compounds during the roasting process. Distinctive mass spectral profiles were observed at different time intervals, and teas with varying fermentation degrees exhibited different chemical fingerprints. The detected compounds included N-heterocyclics, esters, amines, alcohols, amino acids. Some are characteristic tea flavor compounds while others are Maillard reaction products. Multivariate data analysis clearly differentiated tea samples based on the acquired mass spectral data. With its miniaturized design and simple operation, SICRIT demonstrated excellent performance for direct analysis of odor compounds. The integrated SICRIT-MS system enabled direct, real-time analysis of volatile compounds through continuous vapor generation, transfer, and ionization, providing a simple and efficient analytical approach that requires no sample pretreatment or front-end separation.

Anuj Singh Parihar, Bhawna Gupta, Parth Shailesh Bhatt et al.

Background: Leukemia and its treatment compromise oral health, increasing periodontal disease risk in children. This study evaluated the long-term effects of periodontal interventions in children with leukemia. Methods: We reviewed records of 85 children with leukemia receiving periodontal treatment at People’s Dental Academy (2010–2020). Data included demographics, leukemia subtype (Acute Lymphoblastic Leukemia [ALL], Acute Myeloid Leukemia [AML], others), chemotherapy, Hematopoietic Stem Cell Transplantation [HSCT] history, periodontal diagnosis (gingivitis, periodontitis), interventions (scaling/root planing, surgery), and clinical parameters (Pocket Depth [PD], Clinical Attachment Level [CAL], Bleeding on Probing [BOP], radiographic bone loss) at baseline, one, three, and five years. Patients with ≥ three-year follow-up were included. Data were analyzed using descriptive statistics and repeated measures analysis of variance (ANOVA). Results: The cohort comprised 45 ALL, 30 AML, and 10 other leukemia subtypes. At baseline, 70% had gingivitis, 30% periodontitis. Scaling/root planing was most common. At one year, PD (3.2 mm to 2.5 mm, P < 0.001) and BOP (60% to 25%, P < 0.001) significantly decreased. Improvements were maintained at three years (PD 2.2 mm, P < 0.01 vs 1 year) and five years. HSCT patients showed similar improvements. No significant differences existed between leukemia subtypes. One patient experienced minor gingival recession post-surgery. Conclusions: Even after chemotherapy or HSCT, periodontal interventions sustain long-term periodontal health in children with leukemia. The importance of maintaining, as well as comprehensive oral health care and periodontal therapy stares at us from the five-year follow-up data. These results also illustrate the scant literature available on the long-term periodontal effects on these patients, pertaining to integrated dental practices. Further longitudinal research is warranted to confirm these results and identify additional risk factors.

Satya Lakshmi Komarraju, D. Sathyanath, Mandala Sathwik et al.

Ozone therapy evolved from a chemically intriguing 18th-century observation to an increasingly standardized medical modality globally. Initially recognized for its powerful antimicrobial function, ozone was introduced into industrial water treatment and subsequently into many clinical uses, including wound healing, infections, and adjuvant cancer therapy. Early innovators Christian Friedrich Schönbein, Nikola Tesla, and Dr. Joachim Hänsler opened up the way for therapeutic applications, which led to inventions like ozone generators and autohemotherapy. Formal attempts at 20th-century development of ozone therapy as associations, academic publications, and research work followed. Major highlights include wartime application, dental and surgical procedure integration, and publication of landmark works. For the 21st century, establishment of the International Scientific Committee of Ozone Therapy (ISCO3) and the Madrid Declaration have marked progress in global standardization and ethical regulation. India’s latest steps, like including ozone therapy in the education and government-sanctioned training programs of naturopathy, are in line with its increasing legitimacy. The known antioxidant, anti-inflammatory, and immunomodulatory effects of the therapy have widened its scope in integrative and complementary medicine. A background check on ozone therapy shows a transition from experimental fringes to evidence-based, internationally used modality with sustainable use in modern healthcare.

Richard Andreas Lindtner, Lukas Kampik, Larissa Noack et al.

Bone infections caused by Staphylococcus aureus and Staphylococcus epidermidis are serious complications in orthopedic surgery. These infections commonly occur in joint replacements, fracture management, and bone grafting procedures. Rapid and accurate pathogen-specific diagnostic methods are urgently needed to support early clinical decisions. Current culture-based methods are slow and delay effective treatment. This study evaluated the diagnostic value of combining Raman microscopy with high-resolution micro-computed tomography (micro-CT). Human bone samples, either uninfected or inoculated with S. aureus or S. epidermidis, were analyzed. Raman spectroscopy detected distinct spectral changes in inoculated bones, including reduced intensity of phosphate (v1PO43−), Amide III, and CH2 deformation bands. A single principal component explained 96%–98% of the variance in these infection-related markers. Specifically, the v1PO43− and CH2 deformation bands effectively differentiated between S. aureus and S. epidermidis infections, capturing 99%–100% variance. Micro-CT analysis showed significant structural changes in inoculated bones. Trabecular volume, number, and spacing were particularly affected. Among these, VOX-BV/TV and Mean1 best differentiated between S. aureus and S. epidermidis infections (both p &lt; 0.0001). Support vector machine (SVM) classification repeated stratified k-folg cross-validation accurately detected inoculation status. Combining Raman and micro-CT features yielded moderately improved classification performance in pathogen-specific discrimination. These findings demonstrate that combining molecular (Raman spectroscopy) and structural (micro-CT) methods allows rapid, non-destructive diagnosis of bone infections. This multimodal approach may improve diagnostic precision, supports timely clinical decisions, and ultimately improves patient outcomes in orthopedic and trauma surgery.

Dharaben J. Joshi, J. R. Koduru, N. Malek et al.

Abstract Graphene oxide (GO) has attracted substantial interest in various fields of science and technology, owing to its remarkable mechanical, electrical and optical properties. It is prepared using the modified Hummers' method and employed as a precursor for the fabrication of graphene-based nanostructure materials. The facile synthesis of reduced graphene oxide and surface-modified GO using GO offers extensive opportunities in analytical chemistry. The surface modification of GO is realized via elemental doping and covalent and non-covalent bonding. It results in the functionalization of GO with different groups such as C–N, N N, N–H, and C–O–C. GO-based sensor technologies are extensively applied to identify numerous trace level analytes. These fluorescent, and electrochemical sensors are utilized primarily for detecting organic, inorganic, and biomolecules and for humidity sensing and bioimaging. The present review provides a holistic summary of not only the important literary aspects associated with GO but also the diverse practical applications of GO-based analytical strategies for the assaying of various target molecules.

Manavalan Madhana Madhubala, Sekar Mahalaxmi

Background: Development of biomimetic nanomaterials for remineralization therapy is an important strategy in minimally invasive dentistry. The size of the therapeutic agent has a great influence on bioavailability, penetration ability, and larger surface area for interaction in hard tissue remineralization through the nonclassical crystallization pathway. This study aimed to comparatively evaluate the remineralization-inducing potential of polydopamine (PDA) and polydopamine nanoparticles (nPDs) on artificially demineralized dentin. Methodology: nPDs were prepared using commercially procured dopamine hydrochloride by the wet precipitation method. Obtained particles were characterized using scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy, particle size analysis and zeta potential determination via dynamic light scattering with a laser particle analyser, X-ray diffraction, X-ray photoelectron spectroscopy, and attenuated total reflectance Fourier transform infrared spectroscopy. The cytocompatibility of nPD and PDA was assessed by (3-(4,5-dimethythiazol-2-yl) 2,5-diphenyl tetrazolium bromide) assay on human dental pulpal stem cell lines. A total of 66 demineralized dentin slabs of 3 mm × 3 mm × 1 mm dimension were immersed in 2 mg/ml of freshly prepared PDA and nPD solutions for 12 hours, followed by reimmersion in calcium and phosphate solution at 37°C days for 10 days. Samples immersed in deionized water were used as a control group. All the specimens were subjected to various remineralization testing methods using SEM-EDX, Vicker’s microhardness, and micro-Raman spectroscopic analysis. The Shapiro–Wilk test was used to assess the normality of the distribution, followed by one-way ANOVA for intergroup analysis and post hoc Tukey’s test for multiple comparisons within groups. Results: nPD exhibited a nanospherical morphology with positive zeta potential. nPD revealed the polymeric amorphous nature with characteristic functional groups and exhibited >80% relative cell viability. nPD promoted superior remineralization ability by the formation of hydroxyapatite closely mirroring the Ca/P ratio of natural dentin with a hardness value significantly closer to the baseline, which was further evidenced by higher-intensity peaks of phosphate, amide, and proline on micro-Raman spectroscopic analysis. Conclusion: Dentin remineralization is more strongly facilitated by nanometric PDA than PDA, which has an enhanced functional remineralization effect.

Christina Margariti, Gabriela Sava, Ina Vanden Berghe et al.

Abstract Stereomicroscopy, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM–EDS), Fourier Transform Infrared spectroscopy with Attenuated Total Reflectance probe (FTIR-ATR), High Performance Liquid Chromatography with a Photodiode Array system (HPLC–PDA), X-ray Fluorescence spectroscopy (XRF), Zooarchaeology by Mass Spectrometry (ZooMS), and 14C dating were applied to an assemblage of textile and leather fragments that belong to the collection of the Byzantine & Christian Museum of Athens in Greece and lacked inventory information.The analyses applied, along with bibliographical research, yielded information on the materials, techniques and provenance of the find. The assemblage of finds consists of a gold thread embroidered silk satin, dyed with shellfish-purple; a gold strip-drawn wire embroidered silk tabby; a gold strip-drawn wire and red silk thread tapestry; a gold-thread embroidery on a tabby background; fragments of braided cord; and leather fragments. The material components could have been produced locally, in the area of the Byzantine Empire, though some of them indicate connections with India and/or China. The assemblage, dated between the mid AD 10th and mid eleventh century, was probably found in 1924 by Andreas Xygopoulos during the excavation of a tomb inside the church of Agia Sophia in Thessaloniki, Greece.

Karthik Nuthalapati, Raviraj Vankayala, Munusamy Shanmugam et al.

Glioblastoma multiforme (GBM) is one of the most aggressive, incurable, and difficult‐to‐treat malignant brain tumor with very poor survival rates. The gold standard in treating GBMs includes neurosurgical resection of the tumor, followed by the chemotherapy and radiotherapy. However, these strategies remain ineffective in treating patients with GBMs, as tumor recurrence always occur in most cases. Therefore, it remains a grand challenge to develop an effective strategy to combat orthotopic glioblastoma with simultaneous imaging capabilities to monitor the therapeutic outcomes. To tackle this challenge, this study demonstrates, for the first time, that a tumor‐specific europium hexaboride (EuB6)‐based nanomedicine surface‐modified with RGD‐K peptide to target αvβ3 integrin receptors overexpressed on the glioblastoma cells. Further, EuB6@RGD‐K NPs are able to exert theranostic capabilities to effectively diagnose and combat difficult‐to‐treat orthotopic glioblastoma tumors using NIR‐II 1064 nm and NIR‐III 1550 nm photodynamic therapy (NIR PDT) effects. In the in vivo experiments, the average half‐life of 55 d for mice treated with EuB6@RGD‐K NPs and exposed to NIR‐III 1550 nm light irradiation is far higher than that of EuB6@RGD‐K NPs exposed to NIR‐II 1064 nm light irradiation (25 d), PBS‐treated mice (20 d) and EuB6@RGD‐K NPs‐treated mice (no light irradiation, 18 d). To the best of our knowledge, this work represents the first example for destructing murine brain tumors via multi‐functional tumor‐specific europium hexaboride‐based nanotheranostic agent to mediate MR imaging‐guided NIR‐II/‐III photodynamic therapy.

B Swathika, Bharath Nagareddy, V Vijith et al.

Background: The efficiency and safety of root canal preparation are significantly influenced by the surface topographies of rotary files. Atomic force microscopy (AFM) provides high-resolution imaging that can reveal detailed surface characteristics of these instruments. Materials and Methods: In this study, three types of rotary files (File A, File B, and File C) were used to prepare the root canals of extracted human molar teeth. A total of 30 molar teeth were divided into three groups (n = 10) and prepared using one of the three rotary files. After preparation, the rotary files were analyzed using AFM to measure surface roughness parameters including average roughness (Ra), root mean square roughness (Rq), and maximum peak height (Rp). Statistical analysis was performed using ANOVA and post hoc tests to compare the differences between the groups. Results: The AFM analysis revealed significant differences in the surface topographies of the rotary files. File A exhibited a Ra of 150 nm, a root mean Rq of 180 nm, and a maximum peak height Rp of 300 nm. File B showed an average roughness (Ra) of 200 nm, a root mean Rq of 230 nm, and a maximum peak height (Rp) of 350 nm. File C had an average roughness (Ra) of 170 nm, a root mean Rq of 210 nm, and a maximum Rp of 320 nm. Statistical analysis indicated that File B had significantly higher roughness parameters compared to File A and File C (P < 0.05). Conclusion: The surface topographies of rotary files vary significantly, which may impact their performance in root canal preparation. File B, with the highest roughness parameters, may pose a greater risk of canal wall damage and debris retention. These findings underscore the importance of selecting appropriate rotary files to optimize endodontic treatment outcomes.

Anuj Singh Parihar, Brahmananda Dutta, Diksha Yadav et al.

In recent years, antioxidants have gained significant attention in the field of dentistry due to their potential therapeutic benefits in various dental conditions. This comprehensive review aims to provide a detailed analysis of the role of antioxidants in dentistry, focusing on their mechanisms of action, clinical applications, and future prospects. The review highlights the potential of antioxidants in preventing and managing oral diseases, promoting oral health, and enhancing the outcomes of dental treatments.

Laila El Anzi, María Soledad García, Eduardo Laborda et al.

Low-cost electrochemical methodologies for the determination of L-ascorbic acid (vitamin C) and the analysis of juices are developed based on its electro-oxidation on carbon screen-printed electrodes. A novel chronoamperometric methodology is developed for the quantification of L-ascorbic acid in fruit juices. The proposed method stands out for its simplicity and rapidity, demonstrating its efficacy in determining L-ascorbic acid content in various fruit juices. Notably, the results obtained with this chronoamperometric approach are compared with those yielded by chromatography, with no significant differences between the two methods being found. Additionally, an electronic tongue is developed for the differentiation of juices based on the square wave voltammetric signals.

Cedeño Estefany, Zhenli Sun, Zijin Hong et al.

Atmosphere aerosols have significant impact on human health and the environment. Aerosol particles have a number of characteristics that influence their health and environmental effects, including their size, shape, and chemical composition. A great deal of difficulty is associated with quantifying and identifying atmospheric aerosols because these parameters are highly variable on a spatial and temporal scale. An important component of understanding aerosol fate is Raman Spectroscopy (RS), which is capable of resolving chemical compositions of individual particles. This review presented strategic techniques, especially RS methods for characterizing atmospheric aerosols. The nature and properties of atmospheric aerosols and their influence on environment and human health were briefly described. Analytical methodologies that offer insight into the chemistry and multidimensional properties of aerosols were discussed. In addition, perspectives for practical applications of atmospheric aerosols using RS are featured.

Mohamed A. El-Gohary

Abstract This paper investigates the marine effects that affect Qait Bey Fortress in Alexandria—Egypt. It presents the results of scientific studies and examinations to evaluate the deterioration conditions that affected archaeological buildings in the marine environment. In Alexandria, many monumental sites and stone buildings have suffered from many aggressive factors of deterioration (mechanical, chemical, and biological), which have caused great harmful appearances and threatened to eradicate them. These effects include the chemical actions resulting from seawater and marine aerosol and the mechanical actions of water waves. (Qait Bey Fortress), as a case study, was periodically investigated by many scientific techniques over five years to check its decay conditions and to define the most suitable conservation approaches and non-destructive methods for preservation. Different techniques and examinations were carried out to evaluate the current deterioration state of the fortress. For example, XRD analysis and PM investigation were used to study the mineralogical compositions, lithotype, and petrographic characteristics of the stone samples. SEM was used to investigate the morphological features of the same samples. AAS was also used for studying the chemical constituents of seawater samples. In addition, microbiological investigations were conducted to evaluate the colored hard crusts that affected the stone surfaces in the fortress. Our results proved that severe deterioration factors influenced the fortress by collaborating with chemical, mechanical, and biological mechanisms. These mechanisms caused several manifestations, such as abrasion and attrition, crystallizing of salt species, mortar desegregation, pitting and minerals’ honeycomb (Alveolar), color changes, in addition to the accumulation of black and colored biogenic hard crusts composed of numerous tightly adjoining pits of several centimeters. Crusts, such as yellow to bluish green, resulted from P. aeruginosa and granular appearance having brownish ting in the center resulted from P. clacis. In addition, other pigmented features resulted from Bacillus firmus and Bacillus atrophaeus. The presence of some black and dark color crusts was attributed to the growth of some fungal species, such as A. niger, A. phoenicis, Cladosporium cladosporioides, and Alternaria alternata.