Search

Ibuprofen is a well-established non-steroidal anti-inflammatory drug, inhibiting the prostaglandin-endoperoxide synthase. One of the key features defining the ibuprofen structure is the doubly intermolecular O–H⋯O＝C hydrogen bond in cyclic dimers as know from carboxylic acids and confirmed by X-ray analysis. Until now, there was neither information about the vaporization enthalpy of ibuprofen nor about how this thermal property is determined by the subtle balance between different types of intermolecular interaction. In this study we derive the vaporization enthalpy of ibuprofen from thermochemical experiments to be. We dissected the hydrogen bond energy, EHB = 45.0 kJ mol−1, exclusively from measured vaporization enthalpies of related aliphatic carboxylic acids, their homomorph methyl esters and alkyl acetates, respectively. This contribution from hydrogen bonding could be confirmed almost quantitatively from quantum chemical calculations of ibuprofen clusters, which also suggest dispersion interaction of similar order (Edisp = 47 kJ mol−1). Following the full analysis of the gas–vapor transition enthalpy, we studied the changing structural components from the solid to the liquid phase of ibuprofen by means of Attenuated Total Reflection Infrared (ATR-IR) spectroscopy. The cyclic dimers as observed in the X-ray patterns are essentially preserved in the liquid state just above the melting point. However, with increasing temperature the doubly hydrogen-bonded cyclic dimers are replaced by singly hydrogen-bonded linear dimers in the liquid ibuprofen. The transfer enthalpy from the temperature-dependent equilibria of both dimers as obtained from the IR intensity ratios of the vibrational bands quantifies for the first time the energy of the released, single hydrogen bond to be EHB = 21.0 kJ mol−1. Overall, we show that a combination of thermodynamics, infrared spectroscopy and quantum chemistry provides quantification and detailed understanding of structure and molecular interaction in ibuprofen and related compounds. [ABSTRACT FROM AUTHOR]

Formation of gratings upon alternating electric field in compositions of highly birefringent liquid crystal (LC) with novel chiral ionic liquid (CIL) enclosed in 10-µm-thick cells is studied. The compatibility of two organic components of the mixture is investigated. The grating is formed in 1–5% CIL mixtures and causes significant changes of the transmission of polarised light through the cells. Transmission of polarisedλ = 633 nm light through the 5% CIL sample is studied with respect to frequency (1 Hz–3 MHz) and amplitude (up to 10 V) of alternating voltage and the results are used for sketch a voltage–frequency phase diagram. Two possible ways of formation of the gratings with perpendicular orientation to that formed from initial state are presented. Two twisting axes in the molecular alignments of the cholesteric LC gratings with perpendicular directions are proposed. Optical switch based on four different states of LC including two gratings with perpendicular directions is proposed. Moreover, behaviour of the rotation of a grating induced by AC field in hybrid planar-homeotropic cell is studied in two frequency regimes and rotation by more than 90° upon change of the AC field amplitude is observed. [ABSTRACT FROM AUTHOR]

There are many techniques and devices for measurement and recording of arterial blood pressure. Some of them allow (enable) additionally to observe the shape of a wave of arterial pressure, which can be regarded as one of the most important diagnostic parameters of human cardiovascular system. This paper presents a novel design and prototype of a new, non-invasive blood waveform measuring device. It expounds theoretical and experimental (including latest preliminary clinical) results obtained during several years of extensive investigations into blood pressure waveform measuring and monitoring problem. According to investigations performed in the laboratory and preliminary clinical evaluation, the sensor has linear steady-state characteristics and satisfactory dynamic properties. It is an efficient and accurate tool for blood pressure waveform monitoring and assessing the cardiovascular condition of the patients. The novelty of this solution is that the device is equipped with a pneumatic pressure sensor based on the pneumatic nozzle flapper amplifier principle with negative feedback. Due to such a technical solution, the device does not require any cuff, which remains an essential component of the majority of contemporary non-invasive blood pressure measurement devices; therefore, it can be used on the artery where the application of a cuff would be impossible (e.g., carotid artery). This advantage makes possible to obtain an accurate shape of blood pressure waveform with high fidelity, comparable to a direct measurement method. Moreover, during the measurement the device converts directly 'pressure into pressure.' Such a principle of operation makes possible to eliminate additional calibration (at the current stage of research we have eliminated the necessity of calibration in laboratory conditions). [ABSTRACT FROM AUTHOR]

The field of bioinspired iontronics, bridging electronic devices and ionic systems, has multiple biological applications. Carbon-based ultracapacitive devices hold promise for controlling bioactive ions via electric double layers due to their high-surface-area and biocompatible porous carbon electrodes. However, the interplay between complex bioactive ions and porous carbons remains unclear due to the variety of structures of bioactive ions present in biological systems. Herein, we investigate the adsorption behavior of a series of bioactive ammonium-based cations with varying alkyl chain lengths in nanoporous carbons. We find that strong physisorption results from the synergistic hydrophobic interaction and electrostatic attraction between porous carbons (with a negative zeta potential) and bioactive cations. Bioactive cations with varying alkyl chain lengths can be irreversibly physically adsorbed and confined within nanoporous carbons resulting in anion enrichment and depletion during electric polarization. This situation, in turn, results in a characteristic memristive behavior in all-carbon capacitive ionic memristor devices. Our findings highlight the relationship between the resistance state of the memristor and ion adsorption mechanisms in all-carbon capacitive devices, which hold potential for future transmitter delivery, biointerfacing, and neuromorphic devices., (© 2024 Wiley‐VCH GmbH.)

Purpose: To evaluate the intra-fractional tumor motion in lung stereotactic body radiotherapy (SBRT) with deep inspiration breath-hold (DIBH), and to investigate the adequacy of the current planning target volume (PTV) margins., Methods: Twenty-eight lung SBRT patients with DIBH were selected in this study. Among the lesions, twenty-three were at right or left lower lobe, two at right middle lobe, and three at right or left upper lobe. Post-treatment gated cone-beam computed tomography (CBCT) was acquired to quantify the intra-fractional tumor shift at each treatment. These obtained shifts were then used to calculate the required PTV margin, which was compared with the current applied margin of 5 mm margin in anterior-posterior (AP) and right-left (RL) directions and 8 mm in superior-inferior (SI) direction. The beam delivery time was prolonged with DIBH. The actual beam delivery time with DIBH (T beam_DIBH ) was compared with the beam delivery time without DIBH (T beam_wo_DIBH ) for the corresponding SBRT plan., Results: A total of 113 treatments were analyzed. At six treatments (5.3%), the shifts exceeded the tolerance defined by the current PTV margin. The average shifts were 0.0 ± 1.9 mm, 0.1±1.5 mm, and -0.5 ± 3.7 mm in AP, RL, and SI directions, respectively. The required PTV margins were determined to be 4.5, 3.9, and 7.4 mm in AP, RL, and SI directions, respectively. The average T beam_wo_DIBH and T beam_DIBH were 2.4 ± 0.4 min and 3.6 ± 1.5 min, respectively. The average treatment slot for lung SBRT with DIBH was 25.3 ± 7.9 min., Conclusion: Intra-fractional tumor motion is the predominant source of treatment uncertainties in CBCT-guided lung SBRT with DIBH. The required PTV margin should be determined based on data specific to each institute, considering different techniques and populations. Our data indicate that our current applied PTV margin is adequate, and it is possible to reduce further in the RL direction. The time increase of T beam_DIBH , relative to the treatment slot, is not clinically significant., (© 2024 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)

The need for novel healthcare treatments and drugs has increased due to the expanding human population, detection of newer diseases, and looming pandemics. The development of nanotechnology offers a platform for cutting-edge in vivo non-invasive monitoring and point-of-care-testing (POCT) for rehabilitative disease detection and management. The advancement and uses of nanobiosensors are currently becoming more common in a variety of scientific fields, such as environmental monitoring, food safety, biomedical, clinical, and sustainable healthcare sciences, since the advent of nanotechnology. The identification and detection of biological patterns connected to any type of disease (communicable or not) have been made possible in recent years by several sensing techniques utilizing nanotechnology concerning biosensors and nanobiosensors. In this work, 2218 articles are drawn and screened from six digital databases out of which 17 were shortlisted for this review by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) technique. As a result, this study uses a systematic methodology to review some recently developed extremely sensitive nanobiosensors, along with their biomedical, point-of-care diagnostics (POCD), or healthcare applications and their capabilities, particularly for the prediction of some fatal diseases based on a few of the most recent publications. The potential of nanobiosensors for medicinal, therapeutic, or other sustainable healthcare applications, notably for ailments diagnostics, is also recognized as a way forward in the manifestation of future trends., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)