Wideband phase-locked loop circuit with real-time phase correction for frequency modulation atomic force microscopy

We have developed a wideband phase-locked loop (PLL) circuit with real-time phase correction for high-speed and accurate force measurements by frequency modulation atomic force microscopy (FM-AFM) in liquid. A high-speed operation of FM-AFM requires the use of a high frequency cantilever which, however, increases frequency-dependent phase delay caused by the signal delay within the cantilever excitation loop. Such phase delay leads to an error in the force measurements by FM-AFM especially with a low Q factor. Here, we present a method to compensate this phase delay in real time. Combined with a wideband PLL using a subtraction-based phase comparator, the method allows to perform an accurate and high-speed force measurement by FM-AFM. We demonstrate the improved performance by applying the developed PLL to three-dimensional force measurements at a mica/water interface. © 2011 American Institute of Physics

Atomic-Scale distribution of water molecules at the mica-Water interface visualized by three-Dimensional scanning force microscopy

金沢大学フロンティアサイエンス機構We have developed a method referred to as three-dimensional scanning force microscopy (3D-SFM) which enables us to visualize water distribution at a solid-liquid interface with an atomic-scale resolution in less than 1 min. The 3D-SFM image obtained at a mica-water interface visualizes 3D distributions of adsorbed water molecules above the center of hexagonal cavities and the laterally distributed hydration layer. The atomically resolved 3D-SFM image showing mirror symmetry suggests the existence of surface relaxation of the cleaved mica surface next to the aqueous environment. © 2010 The American Physical Society

Spatial distribution of lipid headgroups and water molecules at membrane/water interfaces visualized by three-dimensional scanning force microscopy

At biological interfaces, flexible surface structures and mobile water interact with each other to present non-uniform three-dimensional (3D) distributions. In spite of their impact on biological functions, molecular-scale understanding of such phenomena has remained elusive. Here we show direct visualization of such interfacial structures with subnanometer-scale resolution by 3D scanning force microscopy (3D-SFM). We measured a 3D force distribution at an interface between a model biological membrane and buffer solution by scanning a sharp tip within the 3D interfacial space. We found that vertical cross sections of the 3D image taken along a specific lateral direction show characteristic molecular-scale contrasts tilted at 30° to the membrane surface. Detailed analysis of the 3D image reveals that the tilted contrast corresponds to the time-averaged conformation of fluctuating lipid headgroups. On the basis of the obtained results, we discuss the relationships among the hydration structure, headgroup fluctuation, molecular fluidity, and mechanical strength of the membrane. The results demonstrate that 3D-SFM is capable of visualizing averaged 3D distribution of fluctuating surface structures as well as that of mobile water (i.e., hydration structure) at interfaces between biological systems and water. © 2012 American Chemical Society

How should cardiac xenotransplantation be initiated in Japan?

The version of record of this article, first published in Surgery Today, is available online at Publisher’s website: https://doi.org/10.1007/s00595-024-02861-7.The world's first clinical cardiac xenotransplantation, using a genetically engineered pig heart with 10 gene modifications, prolonged the life of a 57-year-old man with no other life-saving options, by 60 days. It is foreseeable that xenotransplantation will be introduced in clinical practice in the United States. However, little clinical or regulatory progress has been made in the field of xenotransplantation in Japan in recent years. Japan seems to be heading toward a "device lag", and the over-importation of medical devices and technology in the medical field is becoming problematic. In this review, we discuss the concept of pig-heart xenotransplantation, including the pathobiological aspects related to immune rejection, coagulation dysregulation, and detrimental heart overgrowth, as well as genetic modification strategies in pigs to prevent or minimize these problems. Moreover, we summarize the necessity for and current status of xenotransplantation worldwide, and future prospects in Japan, with the aim of initiating xenotransplantation in Japan using genetically modified pigs without a global delay. It is imperative that this study prompts the initiation of preclinical xenotransplantation research using non-human primates and leads to clinical studies

HIGH-DOSE-RATE AFTERLOADING INTRACAVITARY IRRADIATION AND EXPANDABLE METALLIC BILIARY ENDOPROSTHESIS FOR MALIGNANT BILIARY OBSTRUCTION

A double lumen catheter was developed as an applicator for the remote afterloading system (RALS) of ⁶⁰Co for the intracavitary irradiation of an obstructed common bile duct due to gallbladder cancer in 1 case and by cholangiocarcinoma in 7 cases. This was followed by the biliary endoprosthesis with expandable metallic stents to maintain patency. The mean survival period after treatment was not long (14 weeks). However, removal of the external drainage tube was possible in 7 of the 8 cases, and none of the 8 cases showed dislodgement or deformity of the stent, or obstruction of the bile duct in the stent-inserted area. This combination effectively provided palliation, and has considerable potential for malignant biliary obstruction

The foremost and greatest barrier to end-stage heart failure treatment: the impact of caregiver shortage

The version of record of this article, first published in Journal of Artificial Organs, is available online at Publisher’s website: https://doi.org/0.1007/s10047-024-01463-x.We examined the number of patients abandoning cardiac replacement therapy due to the inability to secure a designated caregiver. At Osaka University Hospital Heart Center, when we receive a consultation for a patient with severe heart failure from another hospital, a heart failure team makes a visit to the referring hospital as soon as possible. We retrospectively analyzed this hospital-visit database. We received 199 severe heart failure consultations from 2016–2023. Issues identified during hospital visits included age ≥ 65 years (8%), inability to confirm the patient’s intention (8.5%), and explicit refusal of therapy (2.5%). Medical problems included multiple organ failure (18.1%), obesity (13.1%), diabetes (9.5%), malignancy (5.5%), chronic dialysis (1.0%), and other systemic diseases (12.6%). Adherence problems included poor medication compliance (3.5%), history of heavy drinking (2.5%), and smoking (2.0%). Social problems included inadequate family support in 16.1% of patients. Of the 199 patients, 95 (48.0%) proceeded to a heart transplant and LVAD indication review meeting at Osaka University Hospital. The remaining 104 patients (52.0%) did not proceed to the meeting. Reasons included improvement of heart failure with conservative treatment in 37 cases (35.6%), death before discussion in 21 cases (20.2%), medical contraindications in 18 cases (18.3%), lack of caregivers in 18 cases (18.3%; 9.5% of 199 cases), and patient refusal in 5 cases (4.8%). Approximately 10% of patients consulted at Osaka University Hospital Heart Center for severe heart failure abandoned cardiac replacement therapy due to the lack of caregivers

Phase Structure of a 3D Nonlocal U(1) Gauge Theory: Deconfinement by Gapless Matter Fields

In this paper, we study a 3D compact U(1) lattice gauge theory with a variety of nonlocal interactions that simulates the effects of gapless/gapful matter fields. This theory is quite important to investigate the phase structures of QED$_3$ and strongly-correlated electron systems like the 2D quantum spin models, the fractional quantum Hall effect, the t-J model of high-temperature superconductivity. We restrict the nonlocal interactions among gauge variables only to those along the temporal direction and adjust their coupling constants optimally to simulate the isotropic nonlocal couplings of the original models. We perform numerical studies of the model to find that, for a certain class of power-decaying couplings, there appears a second-order phase transition to the deconfinement phase as the gauge coupling constant is decreased. On the other hand, for the exponentially-decaying coupling, there are no signals for second-order phase transition. These results indicate the possibility that introduction of sufficient number of massless matter fields destabilizes the permanent confinement in the 3D compact U(1) pure gauge theory due to instantons.Comment: The version to be published in Nucl.Phys.

Nephrotoxicity with VCM and Nephrotoxins

There is a growing concern about the relationship between vancomycin-associated nephrotoxicity (VAN) and concomitant use of nephrotoxins. We examined this relationship by combined retrospective analyses of two real-world databases. Initially, the FDA Adverse Event Reporting System (FAERS) was analyzed for the effects of concomitant use of one or more nephrotoxins on VAN and the types of combinations of nephrotoxins that exacerbate VAN. Next, electronic medical records (EMRs) of patients who received vancomycin (VCM) at Tokushima University Hospital between January 2006 and March 2019 were examined to confirm the FAERS analysis. An elevated reporting odds ratio (ROR) was observed with increases in the number of nephrotoxins administered (VCM + one nephrotoxin, adjusted ROR (95% confidence interval [CI]) 1.67 [1.51–1.85]; VCM + ≥ 2 nephrotoxins, adjusted ROR [95% CI] 1.54 [1.37–1.73]) in FAERS. EMRs analysis showed that the number of nephrotoxins was associated with higher incidences of VAN [odds ratio: 1.99; 95% CI: 1.42–2.78]. Overall, concomitant use of nephrotoxins was associated with an increased incidence of VAN, especially when at least one of those nephrotoxins was a renal hypoperfusion medication (furosemide, non-steroidal anti-inflammatory drugs, and vasopressors). The concomitant use of multiple nephrotoxins, especially including renal hypoperfusion medication, should be avoided to prevent VAN