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Comparative Quantification of Arterial Lipid by Intravascular Photoacoustic-Ultrasound Imaging and Near-Infrared Spectroscopy-Intravascular Ultrasound
摘要： Intravascular photoacoustic-ultrasound (IVPA-US) imaging and near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) are two hybrid modalities that detect arterial lipid, with comparison necessary to understand the relative advantages of each. We performed in vivo and ex vivo IVPA-US imaging of the iliac arteries of Ossabaw swine with metabolic syndrome (MetS) and lean swine to investigate sensitivity for early-stage atherosclerosis. We repeated imaging ex vivo with NIRS-IVUS for comparison to IVPA-US and histology. Both modalities showed significantly greater lipid in MetS vs. lean swine, but only IVPA-US localized the lipid as perivascular. To investigate late-stage atherosclerosis, we performed ex vivo IVPA-US imaging of a human coronary artery with comparison to NIRS-IVUS and histology. Two advanced fibroatheromas were identified, with agreement between IVPA-measured lipid area and NIRS-derived lipid content. As confirmed histologically, IVPA-US has sensitivity to detect lipid content similar to NIRS-IVUS and provides additional depth resolution, enabling quantification and localization of lipid cores within plaques.
关键词： Swine,Lipid core plaque,Near-infrared spectroscopy,Human,Intravascular imaging,Photoacoustic imaging,Atherosclerosis,Perivascular adipose tissue
更新于2025-09-10 09:29:36
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Coumarin-based Fluorescent Probes for Super-resolution and Dynamic Tracking of Lipid Droplets
摘要： Visualizing and dynamic tracking lipid droplets (LDs) are of great importance to biological research. Herein, two-photon absorption fluorescent small bio-probes based on lipophilic coumarin were developed, which exhibited high selectivity towards LDs in Hela cells. Owing to the good biocompatibility and excellent photo-stability, the probes were applied to realize specific super-resolution visualization of the intracellular LDs in Hela cells, offering us the quantitative results of the amount and diameters of LDs as well. Furthermore, the bio-probes were capable of monitoring the movements of the LDs in real-time. We believe that the bio-probes would provide new avenues to designing bio-imaging and biological diagnosis.
关键词： Fluorescent Probes,Super-resolution,Lipid Droplets,Coumarin-based,Dynamic Tracking
更新于2025-09-10 09:29:36
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Tuning Photoinduced Electron Transfer Efficiency of Fluorogenic BODIPY- <i>α</i> -Tocopherol Analogues
摘要： Fluorogenic analogues of α-tocopherol developed by our group have been instrumental in monitoring reactive oxygen species (ROS) within lipid membranes. Prepared as two-segment trap-reporter (chromanol-BODIPY) probes, photoinduced electron transfer (PeT) was utilized to provide these probes with an off/on switch mechanism warranting the necessary sensitivity. Herein we rationalize within the context of Marcus theory of electron transfer how substituents on the BODIPY core and linker length joining the trap and reporter segments, tune PeT efficiency. DFT and electrochemical studies were used to estimate the thermodynamic driving force of PeT in our constructs. By tuning the redox potential over a 400 mV range, we observed over an order of magnitude increase in PeT efficiency. Increasing the linker length between the chromanol and BODIPY by 2.8 angstroms in turn decreased PeT efficiency 2.7-fold. Our results illustrate how substituent and linker choice enable “darkening” the off state of fluorogenic probes based on BODIPY fluorophores, by favoring PeT over radiative emission from the singlet excited state manifold. Ultimately, our work brings light to the sensitivity ceiling one may achieve in developing fluorogenic antioxidants analogues of α-tocopherol. The work provides general guidelines applicable to those developing fluorogenic probes based on PeT.
关键词： electrochemical studies,α-tocopherol,lipid membranes,reactive oxygen species,redox potential,photoinduced electron transfer,Marcus theory,DFT,Fluorogenic analogues,BODIPY
更新于2025-09-09 09:28:46
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DEVELOPMENT AND VALIDATION OF UV-SPECTROPHOTOMETRIC METHOD FOR ESTIMATION OF HYDROQUINONE IN BULK, MARKETED CREAM AND PREAPARED NLC FORMULATION
摘要： The aim of the present work was to develop a simple, rapid, accurate and economical UV-visible spectrophotometric method for the determination of hydroquinone (HQ) in its pure form, marketed formulation as well as in the prepared nanostructured lipid carrier (NLC) systems and to validate the developed method. HQ was estimated at UV maxima of 289.6 nm in pH 5.5 phosphate buffer using UV-Visible double beam spectrophotometer. Following the guidelines of the International Conference on Harmonization (ICH), the method was validated for various analytical parameters like linearity, precision, and accuracy robustness, ruggedness, limit of detection, quantification limit, and formulation analysis. The obtained results of the analysis were validated statistically. Recovery studies were performed to confirm the accuracy of the proposed method. In the developed method, linearity over the concentration range of 5-40 μg/ml of HQ was observed with the correlation coefficient of 0.998 and found in good agreement with Beer Lambert’s law. The precision (intra-day and inter-day) of the method was found within official RCD limits (RSD<2%). The sensitivity of the method was assessed by determining the limit of detection and limit of quantification. It could be concluded from the results obtained that the purposed method for estimation of HQ in pure form, in the marketed ointment and in the prepared NLC-formulation was simple, rapid, accurate, precise and economical. It can be used successfully in the quality control of pharmaceutical formulations and for the routine laboratory analysis.
关键词： Nanostructured lipid carriers,UV Spectrophotometer,Validation,Hydroquinone
更新于2025-09-09 09:28:46
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Development and Application of FMO Calculation ? DPD Simulation Conbination Scheme; FMO計算-粗視化シミュレーション連携手法の開発と応用;
摘要： We have been developing a combination scheme of fragment molecular orbital (FMO) calculations and dissipative particle dynamics (DPD) simulations in order to predict the structure of functional materials. FMO-DPD simulations for polymer electrolyte membrane, lipid membrane, and protein model were conducted using in-house automatic parameter determination software.
关键词： Fragment Molecular Orbital Method,Lipid Membrane,FMO-DPD Simulation,Polymer Electrolyte Membrane
更新于2025-09-04 15:30:14
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The role of near-infrared spectroscopy in the detection of vulnerable atherosclerotic plaques
摘要： Coronary artery disease is the leading cause of mortality worldwide. Most acute coronary syndromes are caused by a rupture of a vulnerable atherosclerotic plaque which can be characterized by a lipid-rich necrotic core with an overlying thin fibrous cap. Many vulnerable plaques can cause angiographically mild stenoses due to positive remodelling, which is why the extent of coronary artery disease may be seriously underestimated. In recent years, we have witnessed a paradigm shift in interventional cardiology. We no longer focus solely on the degree of stenosis; rather, we seek to determine the true extent of atherosclerotic disease. We seek to identify high-risk plaques for improvement in risk stratification of patients and prevention. Several imaging methods have been developed for this purpose. Intracoronary near-infrared spectroscopy is one of the most promising. Here, we discuss the possible applications of this diagnostic method and provide a comprehensive overview of the current knowledge.
关键词： vulnerable plaque,near-infrared spectroscopy,lipid-core plaque
更新于2025-09-04 15:30:14
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Current OCT Approaches Do Not Reliably Identify TCFAs
摘要： It is now clearly established that Thin-Capped Fibroatheromas (TCFAs) lead to most Acute Coronary Syndromes (ACSs). The ability to selectively intervene on TCFAs predisposed to rupture and ACSs would dramatically alter the practice of cardiology. While the ability of OCT to identify thin walled plaques at micron scale resolutions has represented a major advance, it is a misconception that it can reliably identify TCFAs. One major reason is that the ‘diffuse border’ criteria currently used to determine ‘lipid plaque’ is almost undoubtedly from high scattering in the intima and not because of core composition (necrotic core). A second reason is that, rather than looking at lipid collections, studies need to be focused on identifying necrotic cores with OCT. Necrotic cores are characteristic of TCFAs and not lipid collections. Numerous other OCT approaches are available which can potentially accurately assess TCFAs, but these have not been aggressively pursed which we believe likely stems in part from the misconceptions over the efficacy of ‘diffuse borders’.
关键词： Myocardial infarction,Optical coherence tomography: OCT,Macrophages,Plaque rupture,Acute coronary syndrome: ACS,Thin capped fibroatheroma: TCFA,Lipid,Massachusetts General Hospital Lightlab
更新于2025-09-04 15:30:14
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Physiological Response to Different Irradiation Regimes during Barley Seedlings Growth Followed by Drought Stress under Non-Photoinhibitory Light
摘要： Differences in physiological response of barley seedlings cultivated under low (LI, ~65 μmol m-2 s-1) and elevated irradiation (EI, ~450 μmol m-2 s-1) to upcoming drought were evaluated. After ten days of cultivation, drought stress was induced under LI by withholding water and was defined as: mild stress (MS), severe stress (SS), extreme stress (ES) and control (C, well watered). Decreased relative water content (RWC) in both LI and EI grown plants was associated with increased lipid peroxidation (TBARS) and electrolyte leakage (%EL) as well as with decreased total chlorophylls content at SS and ES. Antioxidative response to drought was, generally, indicated by higher accumulation of free proline, increased activities of catalase (CAT), guaiacol peroxidase (GPOD) and ascorbate peroxidase (APX). Even the majority of estimated physiological and biochemical parameters showed no differences between investigated light regimes before drought stress induction, the LI grown plants responded on drought by adjustment of the photosynthetic apparatus to prevent photoinhibitory oxidative damage. Photosynthesis downregulation in EI grown plants under ES was revealed due to reduced values of maximum quantum yield of photosystem II (Fv/Fm) and performance index (PIABS) showing that acclimatization to EI conditions lowered their tolerance to the following drought stress although it was applied under low irradiation (LI). Therefore, those plants had reduced capability to cope with the challenge of upcoming drought stress showing more pronounced cellular oxidative damage (SS and ES), less efficient and almost dysfunctional photosynthetic apparatus in extreme drought (ES).
关键词： antioxidative response,photosynthesis,Hordeum vulgare,light regime,drought stress,lipid peroxidation
更新于2025-09-04 15:30:14
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Characterization of the thickness of the tear film lipid layer using high resolution microscopy
摘要： Interferometry is an optical technique that have been used to quantify the lipid layer of the precorneal tear film, and to investigate the relationship between lipid layer thickness and tear film evaporation. However, the relationship between lipid layer thickness and the rate of evaporation is far from consistent. One possible reason is the inherent limit of contemporary interferometric systems, which employ objectives with relatively long depth of focus (DOF) (>15 μm or more), which tend to collect excessive extra-planar noise. This limitation may negatively affect the accuracy of the characterization and thickness measurement of the lipid layer. The current system incorporated an objective with limited DOF (~1.5 μm) into a custom-built optical microscope to image the tear film lipid layer in humans. An algorithm was also developed to process these images. One major outcome of this system is that thick lipid layers exhibit higher variation in thickness values than thin or normal-thickness lipid layers. The variations may reflect the structural differences of the lipid layer, which may offer a novel dimension to explain the missing correlation between lipid layer thickness and evaporation. In summary, the development of the high resolution microscopy system and associated data processing algorithm may provide new insights into the lipid layer structure, topography and their relation to the tear film evaporation rate.
关键词： tear film,dry eye,interferometry,lipid layer thickness
更新于2025-09-04 15:30:14
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ATR FTIR Spectroscopic Study on Insect Body Surface Lipids Rich in Methylene-Interrupted Diene
摘要： To protect themselves, insects cover their bodies with what is called cuticular lipid. The cuticular lipid of American cockroach has a unique lipid content; the most abundant is a cis-alkadiene, cis, cis-6, 9-heptacosadiene amounting to about 70%, which is followed by a branched alkane 3-methylpentacosane. In order to clarify the structural features of the unique lipid composition below the critical temperature, the cuticular lipid was studied by Fourier Transform Infrared (FTIR) spectroscopy in combination with attenuated total reflection (ATR) sampling technique. The infrared spectra measured on an extracted lipid sample at 20°C suggested that the lipid keeps an appreciable level of conformational and lateral packing regularity, in spite of high cis-unsaturated lipid content and also a highly disordered condition around the methyl terminals and cis-olefin groups. The CH2 scissoring and the CH2 rocking regions showed the characteristics of the O⊥ subcell. The same characteristics were observed also by in-situ measurements on a forewing of American cockroach. Combining the spectral features of these bands and the physicochemical properties of each component, it can be inferred that saturated lipids form highly ordered domains within the liquid containing the cis, cis-diene as main component. For comparison, the cuticular lipid of male cricket, which consisted many different hydrocarbons including 15 percent of unsaturated hydrocarbons, showed a lower regularity both in the conformation and in the lateral packing of hydrocarbon chains. These results imply that not only the degree of cis-unsaturation but also the chemical structure diversity of hydrocarbons is the important factor to determine the physicochemical properties of cuticular lipid.
关键词： cuticular lipid,American cockroach,FTIR spectroscopy,lateral packing,methylene-interrupted diene,cis-unsaturated lipids,ATR sampling technique,hydrocarbon chains,conformational order
更新于2025-09-04 15:30:14