Mechanism of Nucleation Pathway Selection in Binary Lennard-Jones Solution: A Combined Study of Molecular Dynamics Simulation and Free Energy Analysis

The nucleation process, which is the initial step in particle synthesis, determines the properties of the resultant particles. Although recent studies have observed various nucleation pathways, the physical factors that determine these pathways have not been fully elucidated. Herein, we conducted molecular dynamics simulations in a binary Lennard-Jones system as a model solution and found that the nucleation pathway can be classified into four types depending on microscopic interactions. The key parameters are (1) the strength of the solute–solute interaction and (2) the difference between the strengths of the like-pair and unlike-pair interactions. The increment of the former alters the nucleation mechanism from a two-step to a one-step pathway, whereas that of the latter causes quick assembly of solutes. Moreover, we developed a thermodynamic model based on the formation of core-shell nuclei to calculate the free energy landscapes. Our model successfully described the pathway observed in the simulations and demonstrated that the two parameters, (1) and (2), define the degree of supercooling and supersaturation, respectively. Thus, our model interpreted the microscopic insights from a macroscopic point of view. Because the only inputs required for our model are the interaction parameters, our model can a priori predict the nucleation pathway

Ventilatory and Pulmonary Vascular Responses to Acute Hypoxia in Patients with Chronic Obstructive Lung Disease

The present study was undertaken to examine the pulmonary vascular and ventilatory responses to acute hypoxia in chronic obstructive lung disease. Pulmonary hemodynamics, minute ventilation (VE) and oxygen uptake (VO2) were serially measured during inhalation of 13 %O2 for 15 min. There was a wide variablility in the pulmonary, vascular response to acute hypoxia. ,The initial increase in VE and the magnitude of change in VO2 were significantly lower in subjects developing a 25 % or great increase in mean pulmonary arterial pressure during hypoxic breathing. These results suggest that the ventilatory response to acute hypoxia plays a significant role in the pulmonary vascular response to acute hypoxia, and blunted initial ventilatory response to acute hypoxia may be a physiological adaptation to enhanced responses of pulmonary vessels

Effect of Acute Hyperoxia and Hypoxia on the Central Blood Volume in Patients with Chronic Pulmonary Diseases

To investigate whether the central blood volume (CBV) reflects the pulmonary vasculature, we measured CBV before and after the inhalation of 100 % or 13 %O2 for 15 min in patients with chronic pulmonary diseases. Using the Stewart-Hamilton technique, we measured CBV using a lung water computer, employing sodium as an indicator. Thirteen patients inhaled 100 % O2, while 8 patients breathed 13 % O2. Hyperoxia increased CBV significantly and the delta change in CBV(△CBV)correlated significantly with the change in total pulmonary resistance index(△TPPI;r=-0.65, p<0.02),the change in mixed venous oxygen tension(△PvO2; r = - 0.58, p < 0.05) and the change in the coefficient of oxygen delivery (△COD;r=0.71, p<0.02). Hypoxic breathing caused little or no change in CBV, but △CBV correlated well with△TPRI(r=-0.74, p<0.05)and△PvO2 (r=0.85,p<0.01)。 Our results suggest that△CBV provides a good index of the pulmonary vascular bed, on which efficient gas-exchange occurs

Feasibility study of a novel wireless localization technique using radiofrequency identification markers for small and deeply located lung lesions

Objectives: To evaluate the safety and efficacy of a novel wireless localization technique that uses radiofrequency identification markers for small and deep lung lesions. Methods: Preliminary use of the device was retrospectively evaluated in 2 Japanese centers. Under general anesthesia, a marker was placed as close as possible to the tumor via computed tomography-guided bronchoscopy in a hybrid operation theater. Surgeons located the marker without lung palpation using a detection probe the tone of which changed to indicate the marker-probe distance. Efficacy was defined as functional marker placement (bronchoscopy time and marker position) and deep margin distance. Results: Twelve markers were placed for 11 lesions (mean size, 6.8 ± 2.7 mm) located at a mean depth from the pleura of 11.4 ± 8.4 mm (range = 0-26.0 mm). Of 12 markers, 7 markers (58.3%) were placed within 10 mm from the lesion in 25.5 ± 14.4 minutes. For the 11 wedge resections, markers were placed at a mean distance of 6.7 mm (range, 0-13.0 mm) from the lesion and a mean distance of 14.4 mm (range, 3.0-42.0 mm) from the pleura. All markers were recovered without complications, and all tumors were resected with negative margins. For 5 lesions >10 mm deep to the pleura (mean depth, 18.9 ± 5.5 mm; range, 11.0-26.0 mm), the median depth of the surgical margin was 11.6 ± 2.1 mm (range, 9.0-14.0 mm). Conclusions: Radiofrequency identification marking was safe and precisely localized small lung lesions, including their depth

Generalised analytical method unravels framework-dependent kinetics of adsorption-induced structural transition in flexible metal–organic frameworks

ゲート型吸着剤はガス分子をどう取り込む？ --サブ秒でのX線回折測定が動的過程を紐解く--. 京都大学プレスリリース. 2023-11-08.Flexible metal–organic frameworks (MOFs) exhibiting adsorption-induced structural transition can revolutionise adsorption separation processes, including CO₂ separation, which has become increasingly important in recent years. However, the kinetics of this structural transition remains poorly understood despite being crucial to process design. Here, the CO₂-induced gate opening of ELM-11 ([Cu(BF₄)₂(4, 4’-bipyridine)₂]n) is investigated by time-resolved in situ X-ray powder diffraction, and a theoretical kinetic model of this process is developed to gain atomistic insight into the transition dynamics. The thus-developed model consists of the differential pressure from the gate opening (indicating the ease of structural transition) and reaction model terms (indicating the transition propagation within the crystal). The reaction model of ELM-11 is an autocatalytic reaction with two pathways for CO₂ penetration of the framework. Moreover, gas adsorption analyses of two other flexible MOFs with different flexibilities indicate that the kinetics of the adsorption-induced structural transition is highly dependent on framework structure

Evaluation of Right Ventricular overload by ^<123>I-MIBG, ^<123>I-BMIPP , and ^<99m>Tc-MIBI

It is important to evaluate the severity of right ventricular (RV) overload in patients with chronic pulmonary diseases or pulmonary thromboembolism because their prognosis depend on the severity of RV overload. Various examination methods have been used to non-invasively evaluate the severity of RV overload. We evaluated the usefulness of recently developed novel radiopharmaceuticals 123I-MIBG, 123I-BMIPP, and 99mTc-MIBI) in patients with chronic respiratory diseases or pulmonary thromboembolism. Myocardial scintigraphy using 1231-MIBG revealed that the ratio of scintillation counts in the interventricular septum (IVS) to those in the left ventricle (LV) correlated negatively with the mean pulmonary arterial pressure (MPAP), suggesting the presence of sympathetic neuropathy due to RV overload. Myocardial scintigraphy using 123I-BMIPP revealed that the ratio of scintillation counts in the RV to those in LV (RV/LV uptake ratio) correlated with MPAP. There was a negative correlation between RV metabolic index [RVMI = (RV/LV ratio of 123I-BMIPP uptake)(RV/LV ratio of 201T1 uptake)] and MPAP. These findings suggested the presence of RV overload-induced fatty acid metabolic disorder. 99iTc-MIBI allows the simultaneous performance of both cardiac pool scintigraphy and myocardial single photon emission computed tomography. RV/LV ratio of 99Tc-MIBI uptake correlated with MPAP. Moreover, RV ejection fraction (RVEF) obtained by right cardiac pool scintigraphy correlated with the RVEF determined by the thermodilution method, suggesting the usefulness of 99mTc-MIBI. Our findings suggest that these radiopharmaceuticals are useful for evaluating the severity of RV overload in patients with chronic respiratory diseases or pulmonary thromboembolism, as well as for evaluating RV overloadinduced metabolic disorders

Fast Gas‐Adsorption Kinetics in Supraparticle‐Based MOF Packings with Hierarchical Porosity

Metal–organic frameworks (MOFs) are microporous adsorbents for high-throughput gas separation. Such materials exhibit distinct adsorption characteristics owing to the flexibility of the crystal framework in a nanoparticle, which can be different from its bulk crystal. However, for practical applications, such particles need to be compacted into macroscopic pellets, creating mass-transport limitations. In this work, this problem is addressed by forming materials with structural hierarchy, using a supraparticle-based approach. Spherical supraparticles composed of nanosized MOF particles are fabricated by emulsion templating and they are used as the structural component forming a macroscopic material. Zeolitic imidazolate framework-8 (ZIF-8) particles are used as a model system and the gas-adsorption kinetics of the hierarchical material are compared with conventional pellets without structural hierarchy. It is demonstrated that a pellet packed with supraparticles exhibits a 30 times faster adsorption rate compared to an unstructured ZIF-8 powder pellet. These results underline the importance of controlling structural hierarchy to maximize the performance of existing materials. In the hierarchical MOFs, large macropores between the supraparticles, smaller macropores between individual ZIF-8 primary particles, and micropores inherent to the ZIF-8 framework collude to combine large surface area, defined adsorption sites, and efficient mass transport to enhance performance

A Case of Anomalous Origin of the Right Coronary Artery from the Left Sinus of Valsalva - Special Reference to PTCA Procedures and Aspirin Effect to Failed PTCA of the Anomalous Coronary Artery -

An unusual case of a 53-year-old male with a right coronary artery originating from the left sinus of Valsalva is presented. Despite acute myocardial infarction due to occlusion of the aberrant right coronary artery (RCA), PTCA was not immediately performed. After 81 mg/day of aspirin had been administered for 1 month, PTCA to the subtotal stenosis of the RCA resulted in failure due to poor deployment of the guiding catheters complicated by withdrawal and uncrossing of a guiding wire. However, complete recanalization occurred after giving the patient 162 mg/day of aspirin for 8 months. Low dose aspirin was effective in recanalizing the subtotal stenosis after failed PTCA

Pulmonary Hypertension in a Patient with Essential Thrombocythemia

A 67-year-old woman with essential thrombocythemia (ET) developed acute heart failure and marked pulmonary hypertension (PH). No clear cause for the PH could be initially found. We suspected that thrombocytosis might cause PH. Treatments with anticoagulant (heparin and warfarin), platelet- lowering (hydroxyurea), and antiplatelet (ticlopidine) agents resulted in improvement of the clinical, hemodynamic conditions, and the control of platelet counts. We found that the main etiology of PH in the present case might be the pulmonary capillary obstruction from local pulmonary microthrombosis complicated with ET. Although PH associated with ET is uncommon, it should be always considered as a possible cause of dyspnea in patients with ET