The halolactonization reaction provides rapid access to densely functionalized lactones from unsaturated carboxylic acids. The endo/exo regioselectivity of this cyclization reaction is primarily determined by the electronic stabilization of alkene substituents, thus making it inherently dependent on substrate structures. Therefore this method often affords one type of halolactone regioisomer only. Herein, we introduce a simple and efficient method for regioselectivity-switchable bromolactonization reactions mediated by HFIP solvent. Two sets of reaction conditions were developed, each forming endo-products or exo-products in excellent regioselectivity. A combination of computational and experimental mechanistic studies not only confirmed the crucial role of HFIP, but also revealed the formation of endo-products under kinetic control and exo-products under thermodynamic control. This study paves the way for future work on the use of perfluorinated solvents to dictate reaction outcomes in organic synthesis.
INTRODUCTION: The Vietnamese Smell Identification Test (VSIT) has been validated in determining olfactory dysfunction in the Vietnamese population; however, its value in diagnosing Parkinson's disease (PD) has not been established. METHODS: This case-control study was conducted at University Medical Center HCMC, Ho Chi Minh City, Vietnam. The study sample included non-demented PD patients and healthy controls (HC) who were gender- and age-matched. All participants were evaluated for odor identification ability using the VSIT and the Brief Smell Identification Test (BSIT). RESULTS: A total of 218 HCs and 218 PD patients participated in the study. The median VSIT and BSIT scores were significantly different between PD and HC groups (VSIT, 5 (3) vs. 9 (2), P < 0.0001; BSIT, 6 (3) vs 8 (2), P < 0.0001). Using the cut-off of <8 for correct answers out of 12 odorants, the VSIT had higher sensitivity (84.4%) and specificity (86.2%) than those of the BSIT (sensitivity of 81.7% and specificity of 69.3%) for the diagnosis of PD. The area under the curve (AUC) value was greater for the VSIT than for the BSIT (0.909 vs 0.818). The smell identification scores were not significantly correlated with disease duration, disease severity, or LEDD (all p > 0.05). CONCLUSION: The VSIT can be a valuable ancillary tool for supporting the diagnosis of PD in Vietnam. Olfactory dysfunction in PD was unrelated to the disease duration and severity. The VSIT can be applied to improve the accuracy of clinical PD diagnosis.
Olfaction Disorders , Parkinson Disease , Humans , Smell , Parkinson Disease/complications , Parkinson Disease/diagnosis , Vietnam , Olfaction Disorders/diagnosis , Olfaction Disorders/etiology , Case-Control Studies , Odorants
Skeletal editing is an important strategy in organic synthesis as it modifies the carbon backbone to tailor molecular structures with precision, enabling access to compounds with specific desired properties. Skeletal editing empowers chemists to transform synthetic approaches of target compounds across diverse applications from drug discovery to materials science. Herein, we introduce a new skeletal editing method to convert readily available aromatic carbonyl compounds into valuable unsaturated carboxylic acids with extended carbon chains. Our reaction setup enables a cascade reaction of enolization-[2+2]cycloaddition-[2+2]cycloreversion between aromatic carbonyl compounds and ketals of cyclic ketones to generate unsaturated carboxylic acids as ring-opening products. Through a simple design, our substrates are specifically activated to react at predetermined positions to enhance selectivity and efficiency. This practical method offers convenient access to versatile organic building blocks as well as provides fresh insights into manipulating traditional reaction pathways for new synthetic applications.
The recent revelation of hidden-borane catalysis has revolutionized the field of catalytic hydroboration in organic synthesis. Many nucleophilic reaction promoters, previously believed to be the catalysts, in fact primarily facilitated the formation of borane (BH3), which subsequently acted as the true catalyst. This revelation prompted us to explore the untapped potential of these unexpected transformations, with a view to simplify hydroboration using more cost-effective and environmentally friendly nucleophilic precatalysts. Via computational studies, we were able to identify that water can actually undertake that role. Herein, we report a study on the simple hydroboration of nitriles, a notoriously challenging yet synthetically valuable class of substrates, using nothing more than moisture as an activating agent. This moisture-assisted nitrile hydroboration process can seamlessly integrate with a range of downstream transformations in a one-pot fashion to produce valuable N-containing products such as symmetrical imines, thioureas, and bis(alcohol)amines as well as N-heterocycles such as pyrroles, pyridines, pyridinium salts, 2-iminothiazolines, and carbazoles.
The current study aimed to identify the chemical constituents and bioactivities of the crude ethanolic extract (CEE) and its fractions (ethyl acetate (EAF), hexane (HEF), and aqueous (AEF)) from leaves of cashew (Anacardium occidentale L.) grown in Vietnam. A total of 31 compounds which belong to alkanes, hydrocarbons, iodine, terpenoids, phenolics, and flavonoids were determined by a gas chromatography-mass spectrometry (GC-MS) analysis, with bis(2-ethylhexyl) phthalate being the most prevailing compound. The highest total phenolic and flavonoid contents were obtained in the EAF, followed by HEF, CEE, and AQF. All samples showed promising in vitro antibacterial activity, enzyme inhibition, and anticancer activity. Among the samples tested, the EAF exhibited the highest enzyme inhibition activity against α-amylase and α-glucosidase (IC50 values of 51.24 µg/mL and 99.29 µg/mL, respectively), cytotoxicity activity against HeLa cells (IC50 value of 79.49 µg/mL), and antibacterial activity against Bacillus subtilis and Escherichia coli with MIC values of 5 mg/mL and 2.5 mg/mL, respectively. These findings suggest that the leaves of A. occidentale cultivated in Vietnam are a promising source of bioactive components and that EAF is a promising bioactive material warranting further pharmaceutical investigation.
Introduction: The 12-item Vietnamese smell identification test (VSIT) has been developed to evaluate the olfactory function of the Vietnamese population. This study aimed to investigate the normative value of the VSIT in different age groups and sexes. Methods: This cross-sectional study was conducted at Ho Chi Minh University Medical Center, Vietnam. All participants were evaluated for odor identification ability using the VSIT. We included healthy participants aged 18 years or older with no history of olfactory disturbances. Results: A total of 391 healthy volunteers were recruited with a mean age of 45.80 years (SD: 17.62; range: 18-86; female: 63.4 %). The tenth percentile of scores on the 0-12 VSIT scale was 8.3 in participants aged 18-29 years, 9.0 in 30-39 years, 8.0 in 40-49 years, 7.8 in 50-59 years, 7.9 in 60-69 years and 6.0 in over 70 years. Young adults (18-39 years old) had better olfactory identification ability than older adults (over 50 years), p < 0.001. There was a significant main effect of sex on VSIT score (p = 0.02), suggesting that females outperformed males. Sensitivity to 8 odors were negatively correlated with age: lemon, garlic, banana, coffee, mango, guava, apple and watermelon (p < 0.05 in all cases) whereas four odors were age-independent including orange, fish sauce, soy sauce, and fish. Conclusion: Normative data provide guidance for assessing individual olfactory function. However, there were significant sex and age effects on olfactory identification scores on the VSIT. Therefore, future studies should be conducted to better adjust for those confounders mentioned above.
Applications in chemistry, biology, medicine, and engineering require the large-scale manipulation of a wide range of chemicals, samples, and specimens. To achieve maximum efficiency, parallel control of microlitre droplets using automated techniques is essential. Electrowetting-on-dielectric (EWOD), which manipulates droplets using the imbalance of wetting on a substrate, is the most widely employed method. However, EWOD is limited in its capability to make droplets detach from the substrate (jumping), which hinders throughput and device integration. Here, we propose a novel microfluidic system based on focused ultrasound passing through a hydrophobic mesh with droplets resting on top. A phased array dynamically creates foci to manipulate droplets of up to 300 µL. This platform offers a jump height of up to 10 cm, a 27-fold improvement over conventional EWOD systems. In addition, droplets can be merged or split by pushing them against a hydrophobic knife. We demonstrate Suzuki-Miyaura cross-coupling using our platform, showing its potential for a wide range of chemical experiments. Biofouling in our system was lower than in conventional EWOD, demonstrating its high suitability for biological experiments. Focused ultrasound allows the manipulation of both solid and liquid targets. Our platform provides a foundation for the advancement of micro-robotics, additive manufacturing, and laboratory automation.
BACKGROUND: Correct olfactory identification requires familiarity with the odor stimuli and is culturally dependent. Existing smell identification tests (SIT) are not culturally specific and may not be reliable in detecting hyposmia in all populations. This study aimed to develop a smell identification test suitable for Vietnamese patients (VSIT). METHODS: The study included 4 phases: 1) survey-based evaluation of the familiarity of 68 odors to identify 18 odors for subsequent testing (N = 1050); 2) smell identification test of 18 odors in healthy patients (N = 50) to determine which 12 should be included in the VSIT; 3) comparison of VSIT scores on 12 odors in patients with hyposmia (N = 60; Brief smell identification test (BSIT) score <8 and those with normosmia (N = 120; BSIT score ≥8) to establish the validity of the newly developed test; and 4) retest of the VSIT in 60 normosmic patients from phase 3 (N = 60) to determine test-retest reliability. RESULTS: As expected, the mean (SD) VSIT score was significantly higher in the healthy participants than in the hyposmic patients [10.28 (1.34) vs 4.57 (1.76); P < 0.001]. Using a cut-off score at 8, the sensitivity and specificity of the instrument in detecting hyposmia were 93.3% and 97.5% respectively. The test-retest reliability using the intra-class correlation coefficient was at 0.72 (P < 0.001). CONCLUSION: The Vietnamese Smell Identification Test (VSIT) demonstrated favorable validity and reliability and will allow for assessment of olfactory function in Vietnamese patients.
Olfaction Disorders , Smell , Humans , Olfaction Disorders/diagnosis , Anosmia , Reproducibility of Results , Southeast Asian People , Odorants
INTRODUCTION: Organotin compounds are widely used in the plastic industry. We demonstrate the role of brain magnetic resonance imaging in a patient with leukoencephalopathy. CLINICAL COURSE: A 38-year-old man who worked with trimethyltin and dimethyltin in a polyvinyl chloride factory reported a two-week progression of impaired memory, loss of balance, apathy, tinnitus, scaly darkened skin, and psychomotor slowing that rendered him unable to continue his daily activities. Magnetic resonance imaging revealed diffuse bilateral white matter lesions. Tin concentrations in both blood (344 µ/L) and urine (3,050 µg/L) were elevated. Removal from exposure and treatment with succimer were associated with clinical, laboratory, and imaging improvements. DISCUSSION: The high lipid content of myelin is a likely target for lipid-soluble alkyl tin compounds. CONCLUSIONS: This patient demonstrates the clinical and magnetic resonance imaging findings of organotin toxicity. The contribution of chelation to the patient's recovery is uncertain and warrants further study.
Leukoencephalopathies , Organotin Compounds , Humans , Male , Adult , Organotin Compounds/toxicity , Leukoencephalopathies/chemically induced , Leukoencephalopathies/diagnostic imaging , Brain/diagnostic imaging , Magnetic Resonance Imaging , Lipids
It is expected that human iPS cell-derived cardiomyocytes (hiPSC-CMs) can be used to treat serious heart diseases. However, the properties and functions of human adult cardiomyocytes and hiPSC-CMs, including cell maturation, differ. In this study, we focused on the temperature dependence of hiPSC-CMs by integrating the temperature regulation system into our sensor platform, which can directly and quantitatively measure their mechanical motion. We measured the beating frequency of hiPSC-CMs at different environmental temperatures and found that the beating frequency increased as the temperature increased. Although the rate at which the beating frequency increased with temperature varied, the temperature at which the beating stopped was relatively stable at approximately 20 °C. The stopping of beating at this temperature was stable, even in immature hiPSC-CMs, and was considered to be a primitive property of cardiomyocytes.
Induced Pluripotent Stem Cells , Micro-Electrical-Mechanical Systems , Adult , Humans , Induced Pluripotent Stem Cells/physiology , Temperature , Cell Differentiation , Myocytes, Cardiac/physiology , Cells, Cultured
This study investigates a cantilever-based pressure sensor that can achieve a resolution of approximately 0.2 mPa, over the frequency range of 0.1-250 Hz. A piezoresistive cantilever with ultra-high acoustic compliance is used as the sensing element in the proposed pressure sensor. We achieved a cantilever with a sensitivity of approximately 40 times higher than that of the previous cantilever device by realizing an ultrathin (340 nm thick) structure with large pads and narrow hinges. Based on the measurement results, the proposed pressure sensor can measure acoustic signals with frequencies as low as 0.1 Hz. The proposed pressure sensor can be used to measure low-frequency pressure and sound, which is crucial for various applications, including photoacoustic-based gas/chemical sensing and monitoring of physiological parameters and natural disasters. We demonstrate the measurement of heart sounds with a high SNR of 58 dB. We believe the proposed microphone will be used in various applications, such as wearable health monitoring, monitoring of natural disasters, and realization of high-resolution photoacoustic-based gas sensors. We successfully measured the first (S1) and second (S2) cardiac sounds with frequencies of 7-100 Hz and 20-45 Hz, respectively.
Heart Sounds , Natural Disasters , Acoustics , Sound
Advanced head and neck cancer (HNC) is functionally and aesthetically destructive, and despite significant advances in therapy, overall survival is poor, financial toxicity is high, and treatment commonly exacerbates tissue damage. Although response and durability concerns remain, antibody-based immunotherapies have heralded a paradigm shift in systemic treatment. To overcome limitations associated with antibody-based immunotherapies, exploration into de novo and repurposed small molecule immunotherapies is expanding at a rapid rate. Small molecule immunotherapies also have the capacity for chelation to biodegradable, bioadherent, electrospun scaffolds. This article focuses on the novel concept of targeted, sustained release immunotherapies and their potential to improve outcomes in poorly accessible and risk for positive margin HNC cases.
The carbonyl-olefin metathesis (COM) reaction is an attractive approach for the formation of a new carbon-carbon double bond from a carbonyl precursor. In principle, this reaction can be promoted by the activation of the carbonyl group with a Brønsted acid catalyst; however, it is often complicated as a result of unwanted side reactions under acidic conditions. Thus, there have been only a very few examples of Brønsted-acid-catalyzed COM reactions, all of which required specially designed setups. Herein, we report a new practical homogeneous Brønsted-acid-catalyzed protocol using nitromethane, a readily available solvent, to promote intramolecular ring-closing COM reactions.
Alkenes , Carbon , Alkenes/chemistry , Catalysis , Solvents
Electrical neuron stimulation holds promise for treating chronic neurological disorders, including spinal cord injury, epilepsy, and Parkinson's disease. The implementation of ultrathin, flexible electrodes that can offer noninvasive attachment to soft neural tissues is a breakthrough for timely, continuous, programable, and spatial stimulations. With strict flexibility requirements in neural implanted stimulations, the use of conventional thick and bulky packages is no longer applicable, posing major technical issues such as short device lifetime and long-term stability. We introduce herein a concept of long-lived flexible neural electrodes using silicon carbide (SiC) nanomembranes as a faradic interface and thermal oxide thin films as an electrical barrier layer. The SiC nanomembranes were developed using a chemical vapor deposition (CVD) process at the wafer level, and thermal oxide was grown using a high-quality wet oxidation technique. The proposed material developments are highly scalable and compatible with MEMS technologies, facilitating the mass production of long-lived implanted bioelectrodes. Our experimental results showed excellent stability of the SiC/silicon dioxide (SiO2) bioelectronic system that can potentially last for several decades with well-maintained electronic properties in biofluid environments. We demonstrated the capability of the proposed material system for peripheral nerve stimulation in an animal model, showing muscle contraction responses comparable to those of a standard non-implanted nerve stimulation device. The design concept, scalable fabrication approach, and multimodal functionalities of SiC/SiO2 flexible electronics offer an exciting possibility for fundamental neuroscience studies, as well as for neural stimulation-based therapies.
Electric Stimulation Therapy , Implantable Neurostimulators , Nanostructures , Semiconductors , Carbon Compounds, Inorganic/chemistry , Electric Stimulation Therapy/instrumentation , Membranes, Artificial , Silicon Compounds/chemistry , Silicon Dioxide/chemistry
Wearable sensor devices with minimal discomfort to the wearer have been widely developed to realize continuous measurements of vital signs (body temperature, blood pressure, respiration rate, and pulse wave) in many applications across various fields, such as healthcare and sports. Among them, microelectromechanical systems (MEMS)-based differential pressure sensors have garnered attention as a tool for measuring pulse waves with weak skin tightening. Using a MEMS-based piezoresistive cantilever with an air chamber as the pressure change sensor enables highly sensitive pulse-wave measurements to be achieved. Furthermore, the initial static pressure when attaching the sensor to the skin is physically excluded because of air leakage around the cantilever, which serves as a high-pass filter. However, if the frequency characteristics of this mechanical high-pass filter are not appropriately designed, then the essential information of the pulse-wave measurement may not be reflected. In this study, the frequency characteristics of a sensor structure is derived theoretically based on the air leakage rate and chamber size. Subsequently, a pulse wave sensor with a MEMS piezoresistive cantilever element, two air chambers, and a skin-contacted membrane is designed and fabricated. The developed sensor is 30 mm in diameter and 8 mm in thickness and realizes high-pass filter characteristics of 0.7 Hz. Finally, pulse wave measurement at the neck of a participant is demonstrated using the developed sensor. It is confirmed that the measured pulse wave contains signals in the designed frequency band.
Nowadays, estuarial areas have been strongly affected by the construction of electrical power dams from upstream, downstream urbanization and many types of hazards along the coastal regions. It has resulted in significant changes in estuarine wetland ecosystems between rainy and dry seasons. To avoid estuary vulnerability, monitoring and evaluation of the estuarine ecosystems are very critical tasks. The main goal of this research is to propose and implement a novel deep learning method in monitoring various ecosystems in estuarine regions. The processing speed and accuracy of common neural networks is improved more than ten times through spatial and context paths integrated into a novel Bilateral Segmentation Network (BiSeNet). The multi-sensor and multi-temporal satellite images (including Sentinel-2, ALOS-DEM, and NOAA-DEM images) served as input data. As a result, four BiSeNet models out of 20 trained models achieved a greater than 90% accuracy, especially for interpreting estuarine waters, intertidal forested wetlands, and aquacultural lands in subtidal regions. These models outperformed Random Forest and Support Vector Machine approaches. The best one was used to map estuarine ecosystems from 12 satellite images over a five-year period in the largest estuary in northern Vietnam. The ecosystem changes between dry and rainy seasons were analyzed in detail to assess the ecological succession in estuaries. Furthermore, this model can potentially update new estuarine ecosystem types in other estuarine areas across the world, making possible real-time monitoring and assessing estuarine ecological conditions for sustainable management of wetland ecosystem.
Deep Learning , Wetlands , Conservation of Natural Resources , Ecosystem , Estuaries , Semantics
We report a method to convert substituted tropylium ions into benzenoid derivatives.
The alternating physical properties, especially melting points, of α,ω-disubstituted n-alkanes and their parent n-alkanes had been known since Baeyer's report in 1877. There is, however, no general and comprehensive explanation for such a phenomenon. Herein, we report the synthesis and examination of a series of novel ω-phenyl n-alkyl tropylium tetrafluoroborates, which also display alternation in their physicochemical characters. Despite being organic salts, the compounds with odd numbers of carbons in the alkyl bridge exist as room temperature ionic liquids. In stark contrast to this, the analogues with even numbers of carbons in the linker are crystalline solids. These solid nonconjugated molecules exhibit curious photoluminescent properties, which can be attributed to their ability to form through-space charge-transfer complexes to cause crystallization-induced emission enhancement. Most notably, the compound with the highest photoluminescent quantum yield in this series showed an unusual arrangement of carbocationic dimer in the solid state. A combination of XRD analysis and ab initio calculations revealed interesting insights into these systems.
The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuable N-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
This paper reports on a mask-type sensor for simultaneous pulse wave and respiration measurements and eye blink detection that uses only one sensing element. In the proposed sensor, a flexible air bag-shaped chamber whose inner pressure change can be measured by a microelectromechanical system-based piezoresistive cantilever was used as the sensing element. The air bag-shaped chamber is fabricated by wrapping a sponge pad with plastic film and polyimide tape. The polyimide tape has a hole to which the substrate with the piezoresistive cantilever adheres. By attaching the sensor device to a mask where it contacts the nose of the subject, the sensor can detect the pulses and eye blinks of the subject by detecting the vibration and displacement of the nose skin caused by these physiological parameters. Moreover, the respiration of the subject causes pressure changes in the space between the mask and the face of the subject as well as slight vibrations of the mask. Therefore, information about the respiration of the subject can be extracted from the sensor signal using either the low-frequency component (<1 Hz) or the high-frequency component (>100 Hz). This paper describes the sensor fabrication and provides demonstrations of the pulse wave and respiration measurements as well as eye blink detection using the fabricated sensor.
Micro-Electrical-Mechanical Systems , Blinking , Heart Rate , Pressure , Respiration
