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1.
Nat Commun ; 15(1): 4717, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38830914

RESUMO

Materials with field-tunable polarization are of broad interest to condensed matter sciences and solid-state device technologies. Here, using hydrogen (H) donor doping, we modify the room temperature metallic phase of a perovskite nickelate NdNiO3 into an insulating phase with both metastable dipolar polarization and space-charge polarization. We then demonstrate transient negative differential capacitance in thin film capacitors. The space-charge polarization caused by long-range movement and trapping of protons dominates when the electric field exceeds the threshold value. First-principles calculations suggest the polarization originates from the polar structure created by H doping. We find that polarization decays within ~1 second which is an interesting temporal regime for neuromorphic computing hardware design, and we implement the transient characteristics in a neural network to demonstrate unsupervised learning. These discoveries open new avenues for designing ferroelectric materials and electrets using light-ion doping.

2.
Cureus ; 16(3): e55740, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38586797

RESUMO

Purpose Giant hiatus hernia (GHH) repair is undertaken electively in symptomatic patients, to prevent complications such as gastric volvulus and subsequent mortality. Advances in laparoscopy and perioperative care have reduced the risk of GHH repair, and improvement in quality of life (QoL) has become an important outcome measure. In our unit, we have been assessing QoL in all the operated as well as non-operated patients with GHH, using the "Quality of Life in Reflux and Dyspepsia" (QOLRAD) questionnaire. We sought to evaluate differences in QoL between patients who were managed conservatively for GHH and those who underwent GHH repair over a two-year period. Methods All patients seen in the Upper Gastrointestinal Tertiary Unit in Lancashire Teaching Hospitals NHS Trust with GHH between January 2015 and December 2022 were identified from a prospectively kept database. QOLRAD scores were analyzed and compared between conservatively and operatively managed patients using the Mann-Whitney U test. Demographic and operative outcome data were also collected. Results Eighty-seven patients with GHH were included. QoL of 51 patients improved significantly after elective surgery. Five out of 36 patients, who were initially treated conservatively, elected to have repair during their follow-up period. These 5 Patients had a lower initial QOLRAD score in comparison to those whose management remained conservative (2.72 vs 5.05, Mann Whitney U test p=0.034), and their QOLRAD scores also improved significantly after the operation. QOLRAD scores in conservatively managed patients remained stable over a two-year follow-up period. Conclusion Objectively calculated low QoL may be a more useful tool than subjective symptoms in selecting patients for elective repair of GHH.

3.
Proc Natl Acad Sci U S A ; 121(17): e2318362121, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38630718

RESUMO

Design of hardware based on biological principles of neuronal computation and plasticity in the brain is a leading approach to realizing energy- and sample-efficient AI and learning machines. An important factor in selection of the hardware building blocks is the identification of candidate materials with physical properties suitable to emulate the large dynamic ranges and varied timescales of neuronal signaling. Previous work has shown that the all-or-none spiking behavior of neurons can be mimicked by threshold switches utilizing material phase transitions. Here, we demonstrate that devices based on a prototypical metal-insulator-transition material, vanadium dioxide (VO2), can be dynamically controlled to access a continuum of intermediate resistance states. Furthermore, the timescale of their intrinsic relaxation can be configured to match a range of biologically relevant timescales from milliseconds to seconds. We exploit these device properties to emulate three aspects of neuronal analog computation: fast (~1 ms) spiking in a neuronal soma compartment, slow (~100 ms) spiking in a dendritic compartment, and ultraslow (~1 s) biochemical signaling involved in temporal credit assignment for a recently discovered biological mechanism of one-shot learning. Simulations show that an artificial neural network using properties of VO2 devices to control an agent navigating a spatial environment can learn an efficient path to a reward in up to fourfold fewer trials than standard methods. The phase relaxations described in our study may be engineered in a variety of materials and can be controlled by thermal, electrical, or optical stimuli, suggesting further opportunities to emulate biological learning in neuromorphic hardware.


Assuntos
Aprendizagem , Redes Neurais de Computação , Computadores , Encéfalo/fisiologia , Neurônios/fisiologia
4.
Sci Rep ; 14(1): 9291, 2024 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-38654097

RESUMO

In the dynamic world of fashion, high-heeled footwear is revered as a symbol of style, luxury and sophistication. Yet, beneath the facade of elegance of classy footwear lies the harsh reality of discomfort and pain. Thus, this study aims to investigate the influence of wearing high-heeled shoes on the sensation of pain across different body regions over a period of 6 h. It involved fifty female participants, all habitual wearers of high-heeled shoes, aged between 20 and 30 years. Each participant kept a record of their perceptions of pain and discomfort every hour for a total of 6 h using a 0-10 pain scale with 0 indicating no pain and 10 indicating severe pain. The findings reveal a progressive rise in pain throughout wear, with the most intense pain reported in the back, calcaneus, and metatarsals. The analysis shows that after approximately 3.5 h, participants experience significant increases in pain levels. However, the relationship between heel height and pain is not linear. It appears that a heel height of 7.5 cm is the threshold where overall body pain becomes significant. The study suggests that a duration of 3.5 h of wear and a heel height of 7.5 cm serve as critical points to decrease overall body pain. Moreover, beyond this heel height, knee pain diminishes compared to other body areas possibly due to the shift towards a more neutral posture. The study findings, coupled with the recommendations, can assist footwear designers in crafting not only stylish but also comfortable shoes.


Assuntos
Dor , Sapatos , Humanos , Sapatos/efeitos adversos , Feminino , Adulto , Dor/etiologia , Adulto Jovem , Medição da Dor , Calcanhar
5.
Org Biomol Chem ; 22(5): 945-949, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38197432

RESUMO

Herein, we prepare a new array of N-(α-furanyl) alkyl sulfoximines via a gold catalyzed reaction of enynone with sulfoximine in moderate to very good yields. The reaction involves Michael addition of sulfoximine to enynone, followed by intramolecular cyclization. The presence of two chiral centres led to the formation of a mixture of diastereomers approximately in a 1 : 1 ratio. The salient features of the protocol include broad substrate scope, high efficiency and high yields. The synthetic utility of the protocol is explored using Suzuki-Miyaura cross-coupling and mild, metal-free opening of the furan ring.

6.
Hum Factors ; : 187208231222329, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38166568

RESUMO

OBJECTIVE: With the rapid improvements in drone technology, there is an increasing interest in distal pointing to diffuse drones. This study investigated the effect of depth on distal pointing when the hand does not traverse the entire distance from start to target so that the most suitable mathematical model can be assessed. BACKGROUND: Starting from the Fitts paradigm, researchers have proposed different models to predict movement time when the distance to the target is variable. They do consider distance, but they are based on statistical modeling rather than the underlying control mechanisms. METHODS: Twenty-four participants volunteered for an experiment in a full-factorial Fitts' paradigm task (3 levels of movement amplitude *7 levels of target width *3 levels of distance from participant to screen). Movement time and the number of errors were the dependent variables. RESULTS: Depth has a significant effect when the target width is small, but depth has no effect when the target width is large. The angular version of the two-part model is superior to the one-part Fitts' model at larger distances. Besides, Index of difficulty for distal pointing, IDDP with adjustable k achieves the best fit even though the model is very sensitive to the value of k and the complexity of the model could be resulting in an overfitting. The result implies that the effects of movement amplitude and target width are not comparable and grouping them to form a dependent index of difficulty can be misleading especially when distance is an added variable. CONCLUSION: The angular version of the two-part model is a viable and meaningful description for distal pointing. Even though the IDDP with adjustable k is the best predictor for movement time when depth is an added variable, there is no physical interpretation for it. APPLICATION: A reasonable predictive model for performance assessments and predictions in distal pointing.

7.
Plant Biotechnol J ; 22(4): 848-862, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38127946

RESUMO

Faster vegetative growth and early maturity/harvest reduce plant life cycle time and are important agricultural traits facilitating early crop rotation. GA is a key hormone governing developmental transitions that determine growth speed in plants. An EAR-motif repressor, SlERF36 that regulates various growth transitions, partly through regulation of the GA pathway and GA levels, was identified in tomato. Suppression of SlERF36 delayed germination, slowed down organ growth and delayed the onset of flowering time, fruit harvest and whole-plant senescence by 10-15 days. Its over-expression promoted faster growth by accelerating all these transitions besides increasing organ expansion and plant height substantially. The plant life cycle and fruit harvest were completed 20-30 days earlier than control without affecting yield, in glasshouse as well as net-house conditions, across seasons and generations. These changes in life cycle were associated with reciprocal changes in expression of GA pathway genes and basal GA levels between suppression and over-expression lines. SlERF36 interacted with the promoters of two GA2 oxidase genes, SlGA2ox3 and SlGA2ox4, and the DELLA gene, SlDELLA, reducing their transcription and causing a 3-5-fold increase in basal GA3/GA4 levels. Its suppression increased SlGA2ox3/4 transcript levels and reduced GA3/GA4 levels by 30%-50%. SlERF36 is conserved across families making it an important candidate in agricultural and horticultural crops for manipulation of plant growth and developmental transitions to reduce life cycles for faster harvest.


Assuntos
Giberelinas , Solanum lycopersicum , Humanos , Animais , Giberelinas/metabolismo , Solanum lycopersicum/genética , Proteínas de Plantas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Estágios do Ciclo de Vida , Regulação da Expressão Gênica de Plantas/genética
8.
J Environ Manage ; 348: 119207, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37832293

RESUMO

The combustion of mobil oil leads to the emission of toxic compounds in the environment. In this study, the aromatic and aliphatic hydrocarbon fractions present in a waste mobil oil collected from automobile market were comprehensively identified and their toxicity was evaluated using wheat grain. Lysinibacillus sphaericus strain IITR51 isolated and characterized previously could degrade 30-80% of both aliphatic and aromatic hydrocarbons in liquid culture. Interestingly, the strain IITR51 produced 627 mg/L of rhamnolipid biosurfactant by utilizing 3% (v/v) of waste mobil oil in the presence of 1.5% glycerol as additional carbon source. In a soil microcosm study by employing strain IITR51, 50-86% of 3-6 ring aromatic hydrocarbons and 63-98% of aliphatic hydrocarbons (C8 to C22) were degraded. Addition of 60 µg/mL rhamnolipid biosurfactant enhanced the degradation of both aliphatic and aromatic hydrocarbons from 76.88% to 61.21%-94.11% and 78.27% respectively. The degradation of mobil oil components improved the soil physico-chemical properties and increased soil fertility to 64% as evident by the phytotoxicity assessments. The findings indicate that strain IITR51 with degradation capability coupled with biosurfactant production could be a candidate for restoring hydrocarbon contaminated soils.


Assuntos
Hidrocarbonetos Aromáticos , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Tensoativos/metabolismo , Solo/química , Poluentes do Solo/química , Hidrocarbonetos/metabolismo , Microbiologia do Solo
9.
J Pers Med ; 13(8)2023 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-37623527

RESUMO

This study presents ATR-FTIR (attenuated total reflectance Fourier-transform infrared) spectral analysis of ex vivo oesophageal tissue including all classifications to oesophageal adenocarcinoma (OAC). The article adds further validation to previous human tissue studies identifying the potential for ATR-FTIR spectroscopy in differentiating among all classes of oesophageal transformation to OAC. Tissue spectral analysis used principal component analysis quadratic discriminant analysis (PCA-QDA), successive projection algorithm quadratic discriminant analysis (SPA-QDA), and genetic algorithm quadratic discriminant analysis (GA-QDA) algorithms for variable selection and classification. The variables selected by SPA-QDA and GA-QDA discriminated tissue samples from Barrett's oesophagus (BO) to OAC with 100% accuracy on the basis of unique spectral "fingerprints" of their biochemical composition. Accuracy test results including sensitivity and specificity were determined. The best results were obtained with PCA-QDA, where tissues ranging from normal to OAC were correctly classified with 90.9% overall accuracy (71.4-100% sensitivity and 89.5-100% specificity), including the discrimination between normal and inflammatory tissue, which failed in SPA-QDA and GA-QDA. All the models revealed excellent results for distinguishing among BO, low-grade dysplasia (LGD), high-grade dysplasia (HGD), and OAC tissues (100% sensitivities and specificities). This study highlights the need for further work identifying potential biochemical markers using ATR-FTIR in tissue that could be utilised as an adjunct to histopathological diagnosis for early detection of neoplastic changes in susceptible epithelium.

10.
Cureus ; 15(7): e41340, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37546143

RESUMO

Flabby ridge, also known as a mobile or displaceable ridge, is a common clinical challenge encountered in dental practice. The flabby ridge lacks firmness and stability, causing dentures to become loose and unstable. This can lead to discomfort, difficulty in speaking and eating, and a decreased quality of life for denture wearers. The flabby ridge often lacks the necessary contour and resilience to create an effective seal and maintain suction between the denture base and the underlying tissues. This compromises the retention of dentures, making them prone to dislodgement during normal oral functions. In this report, a modified window technique is presented for the impression of the anterior maxillary flabby ridge. The window ensures that no or little pressure is exerted on the flabby tissue. Therefore, this technique can be easily carried out by general dental practitioners, enabling them to manage flabby ridge complete denture cases within a primary dental care setting.

11.
Mol Divers ; 2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37468705

RESUMO

Natural products (NPs) continue to serve as a structural model for the development of new bioactive molecules and improve the process of identifying novel medicines. The biological effects of coumarins, one of the most researched compounds among NPs, are currently being thoroughly investigated. In the present investigation, we reported the synthesis of nineteen semi-synthetic 3-substituted scoparone analogues, followed by their characterization using analytical methods such as NMR, HPLC, and HRMS. All compounds screened for in vitro and in vivo study for their ability to reduce inflammation. The SAR study worked effectively for this particular scoparone 3-substitution, as compounds 3, 4, 9, 16, 18, and 20 displayed improved in vitro results for TNF-α than the parent molecule. Similarly, compounds 3, and 17 showed a higher percentage of IL-6 inhibition. Compounds 3, 4, and 12 have also been identified by in vivo studies as promising candidates with higher percent inhibition than the parent scoparone molecule. As evident from all in vitro and in vivo studies, compound 3 showed the most potent anti-inflammatory activity among all.

12.
Chemosphere ; 337: 139264, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37348617

RESUMO

Pollution from the oil industries and refineries has worsened various environmental compartments. In this study, indigenous oil degrading bacteria were isolated from crude oil obtained from an Oil and Natural Gas Corporation (ONGC) asset in Ankleshwar, Gujarat, India. Based on 16S rRNA phylogeny, they were identified as Pseudomonas boreopolis IITR108, Microbacterium schleiferi IITR109, Pseudomonas aeruginosa IITR110, and Bacillus velezensis IITR111. The strain IITR108, IITR109, IITR110, and IITR111 showed 80-89% and 71-78% degradation of aliphatic (C8-C40) and aromatic (4-5 ring) hydrocarbons respectively in 45 d when supplemented with 3% (v/v) waste crude oil. When compared to individual bacteria, the consortium degrades 93.2% of aliphatic hydrocarbons and 85.5% of polyaromatic hydrocarbons. It was observed that the total aliphatic and aromatic content of crude oil 394,470 µg/mL and 47,050 µg/mL was reduced up to 9617.75 µg/mL and 4586 µg/mL respectively in 45 d when consortium was employed. The rate kinetics analysis revealed that the biodegradation isotherm followed first order kinetics, with a linear correlation between concentration (hydrocarbons) and time intervals. The half-life of aliphatic (C8-C40) and aromatic hydrocarbons ranged from 200 to 453 h and 459-714 h respectively. All the bacteria efficiently produced catabolic enzymes such as alkane monooxygenase, alcohol dehydrogenase, and lipase during the degradation of crude oil. These findings indicated that the bacterial consortium can be a better candidate for bioremediation and reclamation of aliphatic and aromatics hydrocarbon contaminated sites.


Assuntos
Hidrocarbonetos Aromáticos , Petróleo , Poluentes do Solo , Petróleo/análise , Cinética , Meia-Vida , Solo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Hidrocarbonetos Aromáticos/análise , Hidrocarbonetos/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental , Poluentes do Solo/análise
13.
Mol Neurobiol ; 60(6): 3496-3506, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36879138

RESUMO

Movement disorder (MD) is an important manifestation of neurologic Wilson disease (NWD), but there is a paucity of information on dopaminergic pathways. We evaluate dopamine and its receptors in patients with NWD and correlate the changes with MD and MRI changes. Twenty patients with NWD having MD were included. The severity of dystonia was assessed using BFM (Burke-Fahn-Marsden) score. The neurological severity of NWD was categorized as grades I to III based on the sum score of 5 neurological signs and activity of daily living. Dopamine concentration in plasma and CSF was measured using liquid chromatography-mass spectrometry, and D1 and D2 receptor expression at mRNA by reverse transcriptase polymerase chain reaction in patients and 20 matched controls. The median age of the patients was 15 years and 7 (35%) were females. Eighteen (90%) patients had dystonia and 2 (10%) had chorea. The CSF dopamine concentration (0.08 ± 0.02 vs 0.09 ± 0.017 pg/ml; p = 0.42) in the patients and controls was comparable, but D2 receptor expression was reduced in the patients (0.41 ± 0.13 vs 1.39 ± 1.04; p = 0.01). Plasma dopamine level correlated with BFM score (r = 0.592, p < 0.01) and D2 receptor expression with the severity of chorea (r = 0.447, p < 0.05). The neurological severity of WD correlated with plasma dopamine concentration (p = 0.006). Dopamine and its receptors were not related to MRI changes. The central nervous system dopaminergic pathway is not enhanced in NWD, which may be due to structural damage to the corpus striatum and/or substantia nigra.


Assuntos
Coreia , Distonia , Degeneração Hepatolenticular , Transtornos dos Movimentos , Feminino , Humanos , Adolescente , Masculino , Dopamina/metabolismo , Degeneração Hepatolenticular/metabolismo , Distonia/metabolismo , Coreia/metabolismo , Receptores de Dopamina D2/metabolismo , Corpo Estriado/metabolismo , Receptores de Dopamina D1/metabolismo , Substância Negra/metabolismo , Proteínas de Transporte/metabolismo
14.
Heliyon ; 9(3): e13993, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36915511

RESUMO

Research on traffic accidents have acknowledged that human error is the leading cause of road accidents around the world. In the UAE, those aged between 18 and 30 years are involved in the most accidents. As a result, this study examines the perception, attitude and driving behavior of young adults in the UAE. Virtual Reality (VR) was used to examine driving behavior because it offers alternatives to assess driving behavior with a high degree of immersive experience in a safe and replicable environment. Participants drove through a virtual environment that resembled the urban environment of Abu Dhabi in the UAE, which included six traffic events. A sample of 12 females and 27 males also completed a pre and post-simulation questionnaire to report and evaluate their personal driving experience in Abu Dhabi. The volunteer group represented young drivers with limited driving experience and diverse cultural backgrounds. Results indicated that male drivers were less adhering to safe driving behavior compared to females. Even though both males and females exceeded the designated speed limit, males traveled longer distances over the limit. Additionally, it was found that young drivers tend to overestimate their skills with factors like gender, cultural background, and driving experience being key contributors. The results indicate that traffic authorities should take into consideration different approaches in the formulation of policies related to young drivers with periodic reassessment of skills and training to enhance the safety of driving in the UAE and the region.

15.
Sensors (Basel) ; 23(3)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36772590

RESUMO

Numerous studies have been conducted to prove the calming and stress-reducing effects on humans of visiting aquatic environments. As a result, many institutions have utilized fish to provide entertainment and treat patients. The most common issue in this approach is controlling the movement of fish to facilitate human interaction. This study proposed an interactive robot, a robotic fish, to alter fish swarm behaviors by performing an effective, unobstructed, yet necessary, defined set of actions to enhance human interaction. The approach incorporated a minimalistic but futuristic physical design of the robotic fish with cameras and infrared (IR) sensors, and developed a fish-detecting and swarm pattern-recognizing algorithm. The fish-detecting algorithm was implemented using background subtraction and moving average algorithms with an accuracy of 78%, while the swarm pattern detection implemented with a Convolutional Neural Network (CNN) resulted in a 77.32% accuracy rate. By effectively controlling the behavior and swimming patterns of fish through the smooth movements of the robotic fish, we evaluated the success through repeated trials. Feedback from a randomly selected unbiased group of subjects revealed that the robotic fish improved human interaction with fish by using the proposed set of maneuvers and behavior.


Assuntos
Procedimentos Cirúrgicos Robóticos , Robótica , Animais , Humanos , Robótica/métodos , Inteligência Artificial , Algoritmos , Redes Neurais de Computação , Peixes
16.
Appl Ergon ; 109: 103996, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36805850

RESUMO

With the emergence of enormous amounts of data, numerous ways to visualize such data have been used. Bar, circular, line, radar and bubble graphs that are ubiquitous were investigated for their effectiveness. Fourteen participants performed four types of evaluations: between categories (cities), within categories (transport modes within a city), all categories, and a direct reading within a category from a graph. The representations were presented in random order and participants were asked to respond to sixteen questions to the best of their ability after visually scanning the related graph. There were two trials on two separate days for each participant. Eye movements were recorded using an eye tracker. Bar and line graphs show superiority over circular and radial graphs in effectiveness, efficiency, and perceived ease of use primarily due to eye saccades. The radar graph had the worst performance. "Vibration-type" fill pattern could be improved by adding colors and symbolic fills. Design guidelines are proposed for the effective representation of data so that the presentation and communication of information are effective.


Assuntos
Movimentos Oculares , Radar , Humanos , Movimentos Sacádicos , Comunicação , Armazenamento e Recuperação da Informação
17.
Nat Chem ; 15(4): 475-482, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36702882

RESUMO

Light-induced catalysis and thermoplasmonics are promising fields creating many opportunities for innovative research. Recent advances in light-induced olefin metathesis have led to new applications in polymer and material science, but further improvements to reaction scope and efficiency are desired. Herein, we present the activation of latent ruthenium-based olefin metathesis catalysts via the photothermal response of plasmonic gold nanobipyramids. Simple synthetic control over gold nanobipyramid size results in tunable localized surface plasmon resonance bands enabling catalyst initiation with low-energy visible and infrared light. This approach was applied to the ROMP of dicyclopentadiene, affording plasmonic polymer composites with exceptional photoresponsive and mechanical properties. Moreover, this method of catalyst activation was proven to be remarkably more efficient than activation through conventional heating in all the metathesis processes tested. This study paves the way for providing a wide range of photoinduced olefin metathesis processes in particular and photoinduced latent organic reactions in general by direct photothermal activation of thermally latent catalysts.

18.
Biosensors (Basel) ; 12(10)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36291048

RESUMO

The antibiotic drug trimethoprim (TMP) is used to treat bacterial infections in humans and animals, and frequently TMP is used along with sulfonamides. However, a large portion of TMP is excreted in its active state, which poses a severe problem to humans and the environment. A sensitive, rapid, cost-effective analytical tool is required to monitor the TMP concentration in biological and environmental samples. Hence, this study proposed an analytical methodology to analyze TMP in clinical, biological and environmental samples. The investigations were carried out using a glucose-modified carbon paste electrode (G-CPE) employing voltammetric techniques. Electrochemical behavior was examined with 0.5 mM TMP solution at optimum pH 3.4 (Phosphate Buffer Solution, I = 0.2 M). The influence of scan rate on the electro-oxidation of TMP was studied within the range of 0.05 to 0.55 V/s. The effect of pH and scan rate variations revealed proton transfer during oxidation. Moreover, diffusion phenomena governed the irreversibility of the electrode reaction. A probable and suitable electrode interaction and reaction mechanism was proposed for the electrochemical oxidation of TMP. Further, the TMP was quantitatively estimated with the differential pulse voltammetry (DPV) technique in the concentration range from 9.0 × 10-7 to 1.0 × 10-4 M. The tablet, spiked water and urine analysis demonstrated that the selected method and developed electrode were rapid, simple, sensitive, and cost-effective.


Assuntos
Grafite , Humanos , Trimetoprima , Glucose , Prótons , Eletrodos , Carbono , Comprimidos , Antibacterianos , Água , Sulfonamidas , Fosfatos
19.
J Mater Chem A Mater ; 10(31): 16585-16594, 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-36091884

RESUMO

The photoelectrochemical oxidation of organic molecules into valuable chemicals is a promising technology, but its development is hampered by the poor stability of photoanodic materials in aqueous solutions, low faradaic efficiency, low product selectivity, and a narrow working pH range. Here, we demonstrate the synthesis of value-added aldehydes and carboxylic acids with clean hydrogen (H2) production in water using a photoelectrochemical cell based solely on polymeric carbon nitride (CN) as the photoanode. Isotope labeling measurements and DFT calculations reveal a preferential adsorption of benzyl alcohol and molecular oxygen to the CN layer, enabling fast proton abstraction and oxygen reduction, which leads to the synthesis of an aldehyde at the first step. Further oxidation affords the corresponding acid. The CN photoanode exhibits excellent stability (>40 h) and activity for the oxidation of a wide range of substituted benzyl alcohols with high yield, selectivity (up to 99%), and faradaic efficiency (>90%).

20.
Chemistry ; 28(29): e202200634, 2022 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-35325491

RESUMO

The photochemical isomerization of α,ß- to ß,γ-unsaturated ketones through a 1,5-hydrogen atom transfer mechanism under mild conditions with high efficiency and selectivity is reported. The reaction is carried out in the absence of metal catalysts or other additives, and its stereoselectivity can be tuned by selecting appropriate solvent mixtures. The reaction's scope and tolerance towards functional groups, including light-sensitive halogens, free acids and alcohols, were studied, providing reliable access to a wide variety of ß,γ-unsaturated ketones. This methodology details the deconjugation of a wide range of unsaturated ketones and, when combined with olefin metathesis, provides an efficient process for either dehomologation or one-carbon double-bond migration of terminal alkenes.

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