Search Results (102)

Asymmetric synthesis of chiral hydroxysulfones, key pharmaceutical intermediates, is challenging. We report an efficient synthesis from readily available materials via a one-pot photo-biocatalytic cascade reaction in aqueous conditions, utilizing visible light as an energy source. This sustainable process achieves up to 84% yields and 99% ee. Engineered ketoreductase produces R-configured products with high conversion and enantioselectivity across diverse substrates. Molecular dynamics (MD) simulations explored enzyme–substrate interactions and their influence on reaction activity and stereoselectivity. Full article

Photochemical degradation is a major removal pathway for pharmaceutical pollutants in water, and dissolved organic matter (DOM) in water is an important factor affecting this process. This study investigates the differential effects of seasonally-varied dissolved organic matter (DOM) from Songhua River and Liao River on the photodegradation of pharmaceutical pollutants, using levofloxacin (LFX), sulfamethoxazole (SMZ), and ibuprofen (IBP) as target compounds. The results demonstrated that summer and autumn DOM inhibited the photodegradation of LFX and SMZ through light screening and dynamic quenching effects, with inhibition rates of 35.1% and 55.5%, respectively, whereas winter DOM enhanced degradation through photo-oxidation mechanisms. DOM from Songhua River and Liao River significantly promoted the photodegradation of IBP. Quenching experiments showed differences in the contributions of photochemically reactive intermediates (PPRIs) to the photodegradation of different target pollutants, with hydroxyl radicals (•OH) dominating LFX photodegradation (48.79% contribution), excited triplet states of DOM (³DOM*) dominating SMZ photodegradation (85.20% contribution), and singlet oxygen (¹O₂) dominating IBP photodegradation (79.89% contribution). The photodegradation pathways were elucidated by measuring the photodegradation by-products of the target pollutants: LFX mainly underwent piperazine ring cleavage and oxidative decarboxylation, SMZ underwent isoxazole ring opening and deamination during photodegradation, and IBP underwent photodecarboxylation and oxidation reactions. Under the influence of the DOM from the Songhua River and Liao River, the generation of multiple photodegradation by-products led to an increasing trend in the acute toxicity of target pollutants to luminescent bacteria. This investigation elucidates the dual regulatory mechanisms of natural aquatic DOM on both photo-induced degradation pathways and toxicity evolution dynamics of pharmaceutical contaminants, which is of great significance for understanding the photochemical transformation behavior and risk assessment of pharmaceutical pollutants in aquatic environments. Full article

Photodynamic therapy (PDT) is a minimally invasive technique—used for the local eradication of neoplastic cells—that exploits the interaction of light, oxygen, and a photo-responsive drug called photosensitizer (PS) for the local generation of lethal ROS. Push-pull chromophores, that bear electron donor (D) and acceptor (A) groups linked through a π-electron bridge, are characterized by a non-homogeneous charge distribution in their excited state, with charge transfer from one extremity of the chain to the other one (Internal Charge Transfer—ICT). This phenomenon has a direct impact on the photophysical features of the push-pull compounds, as the bathochromic shift of the emission maxima and intersystem crossing (ISC) of the excited state are directly connected with the production of reactive oxygen species (ROS). In continuing our research regarding the synthesis and use of oligophenylene ethynylenes (OPEs) in PDT, two new push-pull glycosyl OPE-NOF and OPE-ONF—featuring electron-donor N,N-dimethylamino (N) and dimetoxyaryl (O) and acceptor tetrafluoroaryl (F) moieties on the OPE chain—have been efficiently prepared. The interchanged position of the D groups onto the conjugated skeleton was aimed to tune and optimize the push-pull effect, while the introduction of glucoside terminations was directed to give biocompatibility and bioaffinity to the chromophores. OPE-NOF, OPE-ONF, and the synthetic intermediates were fully characterized, and their photophysical properties were investigated by using UV-Vis absorption and emission spectroscopy. OPE-NOF showed a strong charge-transfer character and high PDT effect on HeLa cancer cells when irradiated with non-harmful blue light, causing massive cancer cell death. Full article

With the proliferation of multi-camera smartphones, image generation has proliferated and cloud storage services have become the primary tool for storing and sharing photos. However, this also poses privacy and security risks. Traditional image encryption techniques, while protecting privacy, also lead to loss of image availability in the cloud. To balance security and availability, TPE (Thumbnail Preserving Encryption) is proposed. However, the decryption effect of the existing schemes is generally unsatisfactory, and many existing schemes are unable to achieve perfect restoration in practical applications. Meanwhile, a few fully reversible schemes are limited by the proposed algorithms, which makes it difficult to be extended to a wider range of applications. To solve this contradiction, this paper proposes a TPE scheme based on reversible information hiding. Specifically, the scheme preserves the DC coefficients of the image during the encryption process and encrypts the AC coefficients to enhance the security of the image, thus obtaining the intermediate encrypted image. Then, the intermediate encrypted image is pre-decrypted, and the subtle error between the original image and the intermediate encrypted image is used as the compensation information. In order to achieve lossless decryption, we introduce the reversible information hiding technique to embed the compensation information into the intermediate image, and we finally obtain the encrypted image. This is also applicable to other high-quality TPE schemes and can provide ideas for their optimization direction. The experimental results show that this scheme not only achieves lossless decryption but also outperforms other TPE schemes in terms of visual effect, while the file extension size is kept at a low level. The research in this paper provides new ideas for balancing image privacy protection and usability, which has important theoretical and practical significance. Full article

This study presents a comprehensive kinetic analysis of sulfamethoxazole (SMX) degradation by the photo-Fenton process, highlighting its potential for removing emerging micropollutants in water treatment. The degradation of SMX followed pseudo-first-order kinetics, with increasing Fe(II) concentrations significantly accelerating the oxidation rate. A kinetic model was developed to describe SMX removal, aromaticity loss, and color changes during treatment. Although SMX was rapidly eliminated, intermediate aromatic and chromophoric compounds persisted, requiring extended reaction times for complete mineralization. The kinetic modeling of aromaticity and color revealed distinct degradation pathways and rate constants, showing a strong dependence on iron dosage. The formation of nitrate and sulfate was used to monitor nitrogen and sulfur mineralization, respectively. Optimal nitrate formation was achieved at 22 mol SMX: 1 mol Fe(II), beyond which excessive iron promoted radical scavenging and the formation of stable Fe–aminophenol complexes, inhibiting complete nitrogen oxidation and aromatic degradation. Moreover, excessive Fe(II) led to increased water coloration due to complexation with partially oxidized aromatic byproducts. These findings emphasize the need for optimized catalyst dosing to balance degradation efficiency and minimize secondary effects. The proposed kinetic models offer a predictive tool for improving photo-Fenton-based treatments and integrating them with biological processes to enhance micropollutant bioremediation. Full article

This study examines the degradation of sulfamethoxazole (SMX) in water using the photo-Fenton process, focusing on dissolved oxygen (DO) dynamics, organic matter mineralization, and water quality improvement. The results show that SMX degradation follows a rapid kinetic pattern, achieving complete removal within 30 min. However, total organic carbon reduction occurs more gradually, indicating the persistence of organic intermediates before full mineralization into CO₂ and H₂O. DO evolution follows a biphasic trend: an initial decline due to oxidative consumption, followed by an increase due to H₂O₂ decomposition into O₂. Initially, at [H₂O₂]₀ ≥ 3.0 mM, DO sharply increases, while at [Fe(II)]₀ = 5.0 mg/L, DO reaches a minimum of 0.3 mg/L due to higher reactive oxygen species (ROS) production. Water quality parameters such as color, turbidity, and aromaticity were also monitored. Aromaticity significantly decreases within 30 min, confirming SMX ring cleavage. Color and turbidity initially intensify and increase due to intermediate formation but later decrease as mineralization progresses. Optimal conditions (1 mol SMX: 10 mol H₂O₂: 0.05 mol Fe(II)) ensure efficient degradation with minimal oxygen depletion without excessive scavenging effects. These findings confirm that the photo-Fenton process effectively removes SMX while improving water quality, making it a sustainable alternative for pharmaceutical wastewater treatment. Full article

A device was developed to study the evolution of fluorescence spectra as a function of time. A previously designed fluorimeter based on the diode array mini-spectrometer CM12880MA was used. The control and measurement were carried out by programming a SAM21D microcontroller. Considerations regarding the optimization of acquisition speed, memory, and computer interface have been analyzed and optimized. As a result, a very versatile device with great adaptability, reduced dimensions, portability, and a low budget (under EUR 500) has been built. The sensitivity, controlled by the integration time of the photodiodes, can be adjusted between 10 µs and 20 s, thus allowing sampling times ranging from 10 ms to more than 10 h. Under these conditions, chemical rate constants from 20 s⁻¹ to 10⁻⁸ s⁻¹ can be experimentally determined. It has a very wide operating range for the kinetic rate constant determination, over six orders of magnitude. As proof of the system performance, the oxidation reaction of Thiamine in a basic medium to form fluorescent Thiochrome has been employed. The evolution of the emission spectrum has been followed, and the decomposition rate constant has been measured at 2.1 × 10⁻³ s⁻¹, a value which matches those values reported in the literature for this system. A Thiochrome calibration curve has also been performed, obtaining a detection limit of 13 nM, consistent with literature data. Additionally, the stability of Thiochrome has been tested, being the photo-decomposition rate constants 1.8 × 10⁻⁴ s⁻¹ and 3.0 × 10⁻⁷ s⁻¹, in the presence and absence of UV light (365 nm), respectively. Finally, experiments have been designed to obtain, in a single measurement, the values of both rate constants: the formation of Thiochrome from Thiamine and its photo-decomposition under UV light to a non-fluorescent product. The rate constant values obtained are in good agreement with those previously obtained through independent experiments under the same experimental conditions. These results show that, under these conditions, Thiochrome can be considered an unstable intermediate in a chemical reaction with successive stages. Full article

The western flower thrips, Frankliniella occidentalis, a worldwide insect pest with its polyphagous feeding behavior and capacity to transmit viruses, follows a diurnal rhythmicity driven by expression of the circadian clock genes. However, it remained unclear how the clock signal triggers the thrips behaviors. This study posed a hypothesis that the clock signal modulates cGMP-dependent protein kinase (PKG) activity to mediate the diurnal behaviors. A PKG gene is encoded in F. occidentalis and exhibits high sequence homologies with those of honeybee and fruit fly. Interestingly, its expression followed a diel pattern with high expression during photophase in larvae and adults of F. occidentalis. It is noteworthy that PKG expression was clearly observed in the midgut during photophase but not in scotophase from our fluorescence in situ hybridization analysis. A prediction of protein–protein interaction suggested its functional association with clock genes. To test this functional link, RNA interference (RNAi) of the PKG gene expression was performed by feeding a gene-specific double-stranded RNA, which led to significant alteration of the two clock genes (Clock and Period) in their expression levels. The RNAi treatment caused adverse effects on early-life development and adult fecundity. To further analyze the role of PKG in affecting diurnal behavior, the adult females were continuously observed for a 24 h period with an automatic digitization device to obtain movement parameters and durations (%) in different micro-areas in the observation arena. Diel difference was observed with speed in RNAi-control females at 0.16 mm/s and 0.08 mm/s, in photo- and scotophase, respectively, whereas diel difference was not observed for the PKG-specific RNAi-treated females, which showed 0.07 mm/s and 0.06 mm/s, respectively. The diel difference was also observed in durations (%) in the control females, more strongly in the intermediate area in the observation arena. Speed and durations in the different micro-areas in mid-scotophase were significantly different from most photophase in the control females, while speed was significantly different mainly during late photophase when comparing effects of control and RNAi treatments in each light phase. Three sequential stages consisting of high activity followed by feeding and visiting of micro-areas were observed for the control females. For RNAi-treated females, the three phases were disturbed with irregular speed and visits to micro-areas. These results suggest that PKG is associated with implementing the diurnal behavior of F. occidentalis by interacting with expressions of the circadian clock genes. Full article

This review will examine the rapidly growing field of soft robotics, with a special emphasis on soft robotic actuators and their applications in bioengineering. Bioengineering has increasingly utilized soft robotics due to their mechanical adaptability and flexibility, with applications including drug delivery, assistive and wearable devices, artificial organs, and prosthetics. Soft robotic applications, as well as the responsive mechanisms employed in soft robotics, include electrical, magnetic, thermal, photo-responsive, and pressure-driven actuators. Special attention is given to hydraulically amplified self-healing electrostatic (HASEL) actuators due to their biomimetic properties and innovative combination of dielectric elastomer actuators (DEAs) and hydraulic actuators, which eliminates the limitations of each actuator while introducing capabilities such as self-healing. HASEL actuators combine the fast response and self-sensing features of DEAs, as well as the force generation and adaptability of hydraulic systems. Their self-healing ability from electrical damage not only makes HASELs a unique technology among others but also makes them promising for long-term bioengineering applications. A key contribution of this study is the comparative analysis of the soft actuators, presented in detailed tables. The performance of soft actuators is assessed against a common set of critical parameters, including specific power, strain, maximum actuation stress, energy efficiency, cycle life, and self-healing capabilities. This study has also identified some important research gaps and potential areas where soft robotics may still be developed in the future. Future research should focus on improvements in power supply design, long-term material durability, and enhanced energy efficiency. This review will serve as an intermediate reference for researchers and system designers, guiding the next generation of advancements in soft robotics within bioengineering. Full article

The photo-thermochemical cycle (PTC) for water splitting offers a sustainable method for hydrogen production by efficiently utilizing solar energy. This study explored the use of CeO₂ as a catalyst in the PTC system to enhance hydrogen yield. A nanostructured CeO₂ catalyst was synthesized via the sol-gel method, achieving an H₂ yield of 8.35 μmol g⁻¹ h⁻¹. Stability tests over five cycles showed consistent yields between 7.22 and 8.35 μmol g⁻¹ h⁻¹. Analysis revealed that oxygen vacancies (V_Os) increased after the photoreaction and depleted during the thermal reaction, which aligns with the expected PTC mechanism for hydrogen production. Single-factor experiments highlighted that photoreaction duration mainly influenced V_Os generation, while thermal duration and temperature impacted V_Os consumption and intermediate reaction rates. A response surface methodology (RSM) model predicted optimal conditions for maximum H₂ yield (8.85 μmol g⁻¹ h⁻¹) with a photoreaction duration of 46.6 min, thermal duration of 45.4 min, and thermal temperature of 547.2 °C. Full article

The utilization of the photo catalytic activation of permonosulfate (PMS) for the combined breakdown of pollutants has become a focal point in research. Layered double hydroxides (LDHs) have a unique layered structure which is conducive to the adsorption and diffusion of reactants, and can provide more active sites for photocatalytic reactions. The anions between the layers can be exchanged with a variety of substances so that specific catalytically active species can be introduced as needed. LDHs themselves have certain catalytic activity, which can produce synergistic catalysis between LDHs and the supported photocatalytic active substances, and further improve the degradation effect of antibiotics. In actual wastewater treatment, LDHs as a catalyst carrier have a good application prospect. However, the poor activation effect is attributed to the low separation efficiency of catalyst carriers and insufficient active sites. In this study, a dual active site system consisting of Co and Fe, known as CoFe-LDHs@MoS₂, was developed as a catalyst to facilitate the synergistic degradation of norfloxacin (NOF) by PMS under visible light. The findings demonstrate that the material possesses an effective capacity for the synergistic degradation of NOF. A comprehensive investigation was conducted to assess the impact of different catalysts, PMS dosage, degradation systems (Vis, PMS, or Vis PMS), catalyst dosage, NOF concentration, pH, and cycle times on the degradation performance. The active free radicals, degradation pathways, and intermediate toxicity were elucidated through capture experiments, Electron Paramagnetic Resonance Spectrometer (ESR) analysis, a liquid mass spectrometry (LC-MS) toxicity assessment, and theoretical calculations. This research offers a novel approach for designing catalysts with exposed high activity sites for the effective removal of NOF from environmental water. Full article

Sulfamethoxazole (SMX) is an antibiotic that is extensively used in veterinary medicine, and its occurrence in wastewater and surface water can reach up to 20 μg/L. SMX is categorized as a pollutant of emerging concern by the US EPA due to its persistence and effects on humans and the environment. In this study, photo-Fenton technology is proposed for the removal of SMX. Aqueous solutions of SMX (50.0 mg/L) are treated in a 150 W UV photoreactor, using [Fe²⁺]₀ = 0.5 mg/L and varying [H₂O₂]₀ = 0–3.0 mM. During the reaction, colour (AU) was assessed along with SMX (mg/L), turbidity (NTU), and TC (mg/L). SMX degrades to aromatic intermediates with chromophoric groups, exhibiting colour (yellow to brown) and turbidity. As these intermediates are mineralized into CO₂ and H₂O, the colour and turbidity of the water lose intensity. Using a molar ratio of 1 mol SMX:10 mol H₂O₂, the maximum degradation of aromatic species takes place (71% elimination), and colourless water with turbidity < 1 NTU is obtained. A kinetic modelling for aromaticity loss and colour formation as a function of the oxidant concentration has been proposed. The application of this model allows the estimation of oxidant amounts for an efficient removal of SMX under environmentally friendly conditions. Full article

Diclofenac (DCF, C₁₄H₁₁Cl₂NO₂) is a widely used non-steroidal anti-inflammatory drug, with a significant occurrence in waste effluents. DCF is especially persistent and difficult to degrade, with numerous toxic effects on aquatic fauna and humans. In 2015, DCF was identified as a priority pollutant (EU Directives on water policy). In this work, UV irradiation and its combination with hydrogen peroxide only or catalyzed by iron salts (photo-Fenton) are analyzed to find the most efficient alternative. DCF aqueous solutions were treated in a stirred 150 W UV photocatalytic reactor. Depending on the case, 1.0 mM H₂O₂ and 0–5.0 mg/L Fe²⁺ catalyst, such as FeSO₄, was added. During the reaction, DCF, pH, turbidity, UVA at 254 and 455 nm, dissolved oxygen (DO), and TOC were assessed. The degradation of DCF yields a strong increase in aromaticity because of the rise in aromatic intermediates (mono-hydroxylated (4-hydroxy-diclofenac and 5-hydroxy-diclofenac) and di-hydroxylated products (4,5-dihydroxy-diclofenac), which subsequently generate compounds of a quinoid nature), which are very stable and non-degradable by UV light. Thus, only if H₂O₂ is added can UV completely degrade these aromatic colour intermediates. However, adding ferrous ion (photo-Fenton) the aromaticity remains constant due to iron com-plexes, that generates maximum colour and turbidity at an stoichiometric Fe²⁺ : DCF ratio of 3. As a result of the study, it is concluded that, with UV light only, a strong yellow colour is generated and maintained along the reaction, but by adding H₂O₂, a colourless appearance, low turbidity (<1 NTU), and [DO] = 8.1 mg/L are obtained. Surprisingly, photo-Fenton was found to be unsuitable for degrading DCF. Full article

Today, we have satellite images of Mars with a resolution of up to 24 cm per pixel. The planet has a thin atmosphere compared to Earth’s, but its surface is revealing itself to be active and complex. The use of images is an increasingly precise means of investigation for the study of transient phenomena that occur on the surface of the planet. We have developed a dating code that could be useful in the study of such phenomena. Thanks to this dating code, it is possible to immediately understand what season is in progress in the observed area starting from the terrestrial reference date of the photos taken by the orbiters. Some intermediate parameters of this calculation, such as the Martian year and the day of the year, can be equally useful for similar investigations. Satellite study of transient phenomena observable on the surface of Mars can range from geology (wind erosion and sedimentation) to meteorology (wind and phase transitions) to indigenous or non-indigenous biology. Full article

As part of the development and production of pharmaceuticals, the purity of Active Pharmaceutical Ingredients stands as a fundamental parameter that significantly influences the quality, safety, and efficacy of the final drug product. Impurities in Active Pharmaceutical Ingredients are various unwanted substances that can appear during the whole manufacturing process, from raw materials to the final product. These impurities can stem from multiple sources, including starting materials, intermediates, reagents, solvents, and even degradation products resulting from exposure to environmental factors such as heat, light, or moisture. Their presence can potentially compromise the therapeutic effect of the drug, introduce unexpected side effects, or even pose safety risks to patients. This study aims to conduct the forced degradation of linagliptin and subsequently attempt to identify the resulting degradants. The degradation procedures were carried out in accordance with the guidelines of the International Committee for Harmonization. The degradation profile of linagliptin was investigated under various conditions, including acid hydrolysis, alkaline hydrolysis, oxidation, heat, and light exposure, utilizing ultra-performance liquid chromatography connected to a photo array detector. Identification and characterization of the degradation products were achieved using an ultra-performance liquid chromatography coupled with a single quadrupole detector mass spectrometer and also a liquid chromatography coupled with a high-resolution mass spectrometry. The identified degradation products demonstrate that linagliptin is particularly susceptible to degradation when exposed to acid and peroxide. Whereas, no significant degradation effects were observed under alkali, thermolytic, and photolytic conditions. Full article