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Background: In the research of coronary artery disease, the precise initial injury that starts the atherosclerotic cascade remains unidentified. Moreover, the mechanisms governing the progression or regression of coronary plaque are not yet fully understood. Based on the concept that the cardiovascular system is a network of pumps and pipes, could fluid mechanics principles and practices elucidate the question of atherosclerosis using flow dynamics images from a novel angiographic technique, focusing on antegrade and retrograde flows and their collisions in iliac and coronary arteries? Methods: From January 2023 to May 2024, coronary angiograms of all hemodynamically stable patients with stable or unstable angina were screened. The angiograms displaying either no lesions (normal) or mild-to-moderate lesions were selected. Each patient underwent an evaluation of flow dynamics and arterial phenomena in both iliac and right coronary arteries. For each artery, data were categorized based on the following parameters: laminar versus non-laminar flow, presence versus absence of collisions, and presence versus absence of retrograde flow. Additionally, in two sub-studies, we analyzed the relationship between retrograde flow and blood pressure, and artificial intelligence algorithms were used to detect the retrograde flow in the right coronary artery. Results: A total of 95 patients were screened, and 51 were included in this study. The results comprised quantitative data (prevalence of laminar flows, collisions, and retrograde flows) and qualitative data (morphological characteristics of antegrade laminar flow, retrograde contrast flow, and instances of flow collision). The results showed that in the iliac artery, laminar flow was observed in 47.06% (24/51) of cases, with collisions noted in 23.53% (12/51). Retrograde flow was present in 47.06% (24/51) of cases, and notably, 75% (18/24) of these cases were associated with uncontrolled diastolic blood pressure (DBP) above 80 mmHg (p < 0.001). Conversely, in the RCA, laminar flow was observed in 54.9% (28/51) of cases, with collisions noted in only 3.92% (2/51). Retrograde flow was identified in 7.84% (4/51) of cases, and all these cases (100%, 4/4) were associated with uncontrolled systolic blood pressure (SBP) above 120 mmHg, though statistical significance was not reached due to the small sample size (p > 0.05). Conclusions: Based on the concept that the cardiovascular system is a network of pumps and pipes, this research methodology provides intriguing insights into arterial flow behaviors by integrating fluid mechanics practices with novel angiographic observations. The preliminary results of this study identified laminar flow as the predominant pattern, with retrograde flow and collisions occurring infrequently. The implications of vortex, collision, and disorganized flow highlight potential mechanisms for endothelial damage and atherosclerosis initiation. Moreover, the correlation with blood pressure underscores the critical role of hypertension management in preventing adverse hemodynamic events. Future directions include refining imaging techniques and further exploring the mechanistic links between flow dynamics and vascular pathophysiology to enhance diagnostic and therapeutic strategies for cardiovascular diseases.

Background: In the research of coronary artery disease, the precise initial injury that starts the atherosclerotic cascade remains unidentified. Moreover, the mechanisms governing the progression or regression of coronary plaque are not yet fully understood. Based on the concept that the cardiovascular system is a network of pumps and pipes, could fluid mechanics principles and practices elucidate the question of atherosclerosis using flow dynamics images from a novel angiographic technique, focusing on antegrade and retrograde flows and their collisions in iliac and coronary arteries? Methods: From January 2023 to May 2024, coronary angiograms of all hemodynamically stable patients with stable or unstable angina were screened. The angiograms displaying either no lesions (normal) or mild-to-moderate lesions were selected. Each patient underwent an evaluation of flow dynamics and arterial phenomena in both iliac and right coronary arteries. For each artery, data were categorized based on the following parameters: laminar versus non-laminar flow, presence versus absence of collisions, and presence versus absence of retrograde flow. Additionally, in two sub-studies, we analyzed the relationship between retrograde flow and blood pressure, and artificial intelligence algorithms were used to detect the retrograde flow in the right coronary artery. Results: A total of 95 patients were screened, and 51 were included in this study. The results comprised quantitative data (prevalence of laminar flows, collisions, and retrograde flows) and qualitative data (morphological characteristics of antegrade laminar flow, retrograde contrast flow, and instances of flow collision). The results showed that in the iliac artery, laminar flow was observed in 47.06% (24/51) of cases, with collisions noted in 23.53% (12/51). Retrograde flow was present in 47.06% (24/51) of cases, and notably, 75% (18/24) of these cases were associated with uncontrolled diastolic blood pressure (DBP) above 80 mmHg (p < 0.001). Conversely, in the RCA, laminar flow was observed in 54.9% (28/51) of cases, with collisions noted in only 3.92% (2/51). Retrograde flow was identified in 7.84% (4/51) of cases, and all these cases (100%, 4/4) were associated with uncontrolled systolic blood pressure (SBP) above 120 mmHg, though statistical significance was not reached due to the small sample size (p > 0.05). Conclusions: Based on the concept that the cardiovascular system is a network of pumps and pipes, this research methodology provides intriguing insights into arterial flow behaviors by integrating fluid mechanics practices with novel angiographic observations. The preliminary results of this study identified laminar flow as the predominant pattern, with retrograde flow and collisions occurring infrequently. The implications of vortex, collision, and disorganized flow highlight potential mechanisms for endothelial damage and atherosclerosis initiation. Moreover, the correlation with blood pressure underscores the critical role of hypertension management in preventing adverse hemodynamic events. Future directions include refining imaging techniques and further exploring the mechanistic links between flow dynamics and vascular pathophysiology to enhance diagnostic and therapeutic strategies for cardiovascular diseases. [ABSTRACT FROM AUTHOR]

In this paper, a mechanism for wet etching on birefringent calcite crystal is discussed. By altering the etchant type, its concentration and the stirring speed, the etching mechanism can be confined within the surface reaction regime, resulting in anisotropic etching. Acetic acid can be used to form V shapes defined by the {101̄1} planes with an intersecting angle of 51 degree. V-groove and blazed grating, with a grating period as small as 2 μm, were successfully fabricated. Such gratings can be used as transmission and reflection devices in the visible and infrared ranges. In addition, a transmission polarization dependent device can also be made by covering the calcite with index matching material. [ABSTRACT FROM AUTHOR]

Transmembrane voltage pulses are known to create transient "pores" in the lipid bilayer. This phenomenon, termed electroporation (EP), has been extensively investigated. EP occurs following electric field pulses of up to 10[sup6] V/cm with duration between µs and ms to membranes in close contact and is believed to initiate primarily in the lipid bilayer. This paper begins with a brief summary of the origin of lipid bilayer research. One of practical applications of EP is cell transfection for gene expression. Other applications include encapsulation of drugs in controlled-release and insertion of proteins in living cells. It seems likely that the presence of membrane proteins affect the EP of the lipid bilayer by changing its mechanical properties. Transport of ions such as Na[sup+], K[sup+], Cl[sup-] through membrane channels discharge the membrane potential, and at times an external pulse of sufficient amplitude and duration tends to cause dielectric breakdown of the lipid bilayer. Molecular transport through primary pores and pores enlarged by secondary processes provides the basis for transporting molecules into and out of cells. Some recent relevant papers on BLM under electric fields are referenced. [ABSTRACT FROM AUTHOR]

A cellulose triacetate (CTA) and three different molecular weights of poly(alphamethyl styrene) (PMS) were used as co-wall materials to prepare composite microcapsules with ethylcellulose (EC). A non-solvent-addition phase-separation method was used. The core material was theophylline (TH) and the solvent-non-solvent pair was dichloromethane-n-hexane, and the drug-release rates of the microcapsules prepared from these two types of co-wall materials were compared. The effects of their phase-separation range on the properties of the microcapsules, such as particle size, release rate and the morphology of the microcapsules are also discussed. The release rate of microcapsules was also affected by the compatibility of the co-wall materials and the EC. The dissolution studies indicated that the drug-release time of CTA/EC and PMS/EC composite microcapsules was sustained to 10 and 3.5 times, respectively, in comparison with that for pure EC microcapsules. [ABSTRACT FROM AUTHOR]

This article reports the electrical responses of a phosphate ionophore, the cyclic polyamine 3-decyl-1,5,8-triazacyclodecane-2,4-dione (N3-cyclic amine) incorporated into metal supported bilayer lipid membranes (s-BLM). Teflon coated silver wire was used as a support. In a potentiometric mode, the ionophore had a response that was linearly related to the logarithm of HPO4(2-) concentration and was also dependant on pH. Selectivity coefficients for other anions compared to HPO4(2-) ions, determined by the separate solution method, fell within the range 1.73 x 10(-4) to 6.38 x 10(-2).

The design of an immunoliposome system for molecular recognition using reconstituted, hydrogel-supported bilayer lipid membranes (sb-BLMs) is described. By monitoring the electrical properties, two kinds of recognition are feasible: (i) the human bladder tumor cells, Ej and its antibody BDI-1, the lifetime of the reconstituted membrane is 42 min; and (ii) the human rectum tumor cells, LOVO, the life of the reconstructed membrane is more than 40 min, the same as conventional BLM. Further, the anticancer drug, Adriamycin (Anticancer Res., 20 (2000) 1391), was shown to be effective in such reconstituted systems, the life of which is less than 5 min. In these experiments, the active ingredients of the Ej and LOVO cells were determined on reconstituted sb-BLMs. The key point is that the component part being recognized on the BLM must be kept in its native state.

Supported bilayer lipid membranes (s-BLMs with and without the doping of fullerene C60) self-assembled on indium-tin oxide (ITO) glass were fabricated and characterized by cyclic voltammetry and electrochemical impedance spectroscopy using a three-electrode system. The photoelectric properties of the ITO supported planar lipid bilayers were studied. Light intensity of irradiation, bias voltage, and concentration of donors have been found to be limiting factors of the transmembrane photocurrent. The facilitation effect of C60 doping in s-BLMs on the photoinduced electron transfer across s-BLM is discussed. This novel self-assembled ITO/s-BLM system may provide a simple and mechanically stable model for the study of the photoelectric and photodynamic properties of biomembranes.