A wide dynamic range diamond quantum sensor as an electric vehicle battery monitor

To demonstrate the application capability of the diamond quantum sensor as an electric vehicle (EV) battery monitor, we (i) investigated the measurable current in a real car noise level and (ii) compared the linearity with conventional sensors. Consequently, (i) we could measure a 20 mA current pulse even under an external magnetic field of 80 µT, which is larger than that of 50 µT around the EV battery module in a real car during driving. The 20 mA pulse measurement corresponds to the EV battery state of charge estimation accuracy of 0.2% in the standard driving pattern, which is smaller than the present level of 10%. (ii) The linearity degradation seen in the Hall sensor near the upper limit of the measurement range was not seen in the diamond sensor. Although the Hall sensor and the shunt resistor showed linearity degradation in the current range of several tens of amperes or less, the degradation was smaller for the diamond sensor. The transverse magnetic field effect in the diamond sensor on the linearity was estimated to be less than 0.01% for a several-degree misalignment of the sensor surface to the magnetic field direction and under a 340 A current. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'.

Damages of DNA in tritiated water

Tritium is a radioisotope of hydrogen emitting low energy β-rays in disintegration to ³He. DNA molecules are damaged mainly by β-ray irradiation, and additional damages can be induced by break of chemical bond by nuclear transmutation to inert ³He. Deep knowledges of the mechanisms underlying DNA damages lead to better understanding of biological effects of tritium. This chapter reviews recent experimental and computer simulation activities on quantitative evaluation of damage rates by β-ray irradiation and nuclear transmutation. The rate of DNA double-strand breaks in tritiated water has been examined using a single molecule observation method. The effects of β-ray irradiation were not noticeable at the level of tritium concentration of ∼kBq/cm³, while the irradiation effects were clear at tritium concentrations of ∼MBq/cm³. The factors affecting on the DSB rate are discussed. A new image processing method for the automatic measurement of DNA length using OpenCV and deep learning is also introduced. The effects of tritium transmutation on hydrogen bonds acting between the two main strands of DNA have been examined using molecular dynamics simulations. The study showed that the collapsing of DNA structure by the transmutation can be quantitatively evaluated using the root mean square deviation of atomic positions.

Refractive index measurements of solid deuterium-tritium

Physical properties of tritium (T) and deuterium (D) have been of great interest as a fuel for nuclear fusion. However, several kinds of the physical properties in a cryogenic environment have not been reported. Optical properties in liquid and solid phases are indispensable for the quality control of the DT fuel. We study the dependence of the refractive index of solid DT on temperature. A dedicated cryogenic system has been developed and forms a transparent solid DT in a prism cell. Refractive index measurements based on Snell's law were conducted. The refractive indexes of solid DT are from 1.1618 ± 0.0002 to 1.1628 ± 0.0002 in the temperature range of 19.40 K to 17.89 K.

Comparison of neointimal coverage between biodegradable-polymer everolimus-eluting stent and durable-polymer everolimus-eluting stent using angioscopy for the patients with acute coronary syndrome

Background

New-generation biodegradable-polymer platinum chromium everolimus-eluting stent (BP-PtCr-EES) is available, which has different polymer and alloy compare to more established stent design, a durable-polymer cobalt-chromium everolimus-eluting stent (DP-CoCr-EES).

Purpose

To compare neointimal coverage (NIC) between BP-PtCr-EES and DP-CoCr-EES by using coronary angioscopy (CAS).

Methods

A total of 36 patients (44 stents) with BP-PtCr-EES or DP-CoCr-EES who underwent CAS at 1 year after stenting were investigated. We compared angioscopic findings assessed by angioscopy between BP-PtCr-EES (n=18) and DP-CoCr-EES (n=26). NIC grade and yellow plaque grade (YPG) was adopted from earlier reports from grade 0 to 3. We determined maximum (max-) and minimum (min-) NIC grade and heterogeneity score (HGS = max NIC grade minus min NIC grade). We also assessed YPG and the presence of thrombus (TH).

Results

Six lesions (33.3%) in BP-PtCr-EES group and 7 (26.9%) lesions in DP-CoCr-EES group were culprit lesions of acute coronary syndrome, which did not statistically differ between the two groups (p=0.74). And there were no significant differences in stent diameter (BP-PtCr-EES: 2.97±0.39 mm vs DP-CoCr-EES: 3.14±0.45 mm, p=0.22) and length (BP-PtCr-EES: 26.9±7.9 mm vs DP-CoCr-EES: 28.4±8.0 mm, p=0.54). In terms of CAS findings, BP-PtCr-EES group has better neointimal coverage than DP-CoCr-EES group (max NIC grade: 2.6±0.7 vs 2.0±0.9, p=0.01. min NIC grade: 1.1±0.8 vs 0.5±0.5, p<0.01), but HGS was almost same (1.6±0.7 vs 1.5±0.9, p=0.70). YPG of BP-PtCr-EES group showed significantly lower than DP-CoCr-EES group (1.0±1.0 vs 1.7±1.0, p=0.02). The rate of TH was significantly lower in BP-PtCr-EES group than DP-CoCr-EES group (25%, n=6, vs 75%, n=18, p=0.03). There were no clinical events such as stent thrombosis or restenosis during the observation period in both stent groups.

Conclusion

Superior neointimal coverage and less YPG or TH were observed by CAS in the BP-PtCr-EES group at 1 year after stenting. Clinical significance was still unknown because of no clinical events in both groups. Prospective and large populations studies may be required.

Funding Acknowledgement

Type of funding source: None

P6439Clinical outcomes of acute coronary syndrome with intact-fibrous cap plaque at the culprit lesions in diabetic and non-diabetic patients

Background

Previous studies revealed that the morphological substrates of the culprit lesion assessed by optical coherence tomography (OCT) in acute coronary syndrome (ACS), which includes ruptured plaque (RP) and intact fibrous cap (IFC) plaque, are associated with subsequent clinical outcomes. Nevertheless, the impact of culprit morphology on clinical outcomes has not been evaluated in patients with diabetes mellitus (DM), which is one of the major determinants of clinical prognosis.

Purpose

We sought to investigate the association of the culprit lesion morphology with clinical outcomes in patients with DM and those without DM.

Methods

We retrospectively investigated a total of 508 patients with acute myocardial infarction (AMI) experiencing their first episode of ACS in whom OCT-guided, primary percutaneous coronary intervention (PCI) was performed and a culprit lesion was observed by OCT with sufficient image quality. Patients were divided into two groups according to the culprit lesion morphology into patients with RP (RP group) and those without RP (IFC group). The rate of major adverse cardiac events (MACE) including death, myocardial infarction, target or non-target lesion revascularizations were compared between RP and IFC groups in patients with DM (DM) and those without DM (non-DM), separately.

Results

MACE was captured in 80 patients during the median follow-up of 505 (IQR 274–1300) days. In non-DM, RP group showed significantly worse MACE-free rate than in IFC group (Figure), In DM, there was no significant difference between RP and IFC groups (Figure).

Figure 1

Conclusion

Culprit lesion morphology assessed by OCT was not associated with clinical outcomes in DM patients unlike non-DM patients. Distinct strategy for secondary prevention may be required for DM patients.

6111Optical coherence tomography derived predictors of restenosis after non-stenting coronary intervention with drug-coated balloon

Background

One of the limitations of metallic stents including contemporary drug eluting stents lies in the permanent existence of metallic materials within the coronary arteries, which may lead to neoatherosclerosis and a long-term use of dual antiplatelet therapy. Some reports have recently suggested the efficacy and safety of non-stent strategy with drug-coated balloon (DCB) angioplasty in combination with debulking devices for de novo lesions. However, little is known about the potential risk of restenosis after percutaneous coronary intervention (PCI) with DCB.

Purpose

We sought to assess the predictive factors of restenosis by optical coherence tomography (OCT) after PCI with DCB instead of metallic stents.

Methods

We retrospectively investigated 49 de novo lesions in 38 patients treated by DCB without stent implantation in whom OCT was performed immediately after PCI and follow-up angiography was performed at median of 5.6 (3.7–6.9) months. OCT findings after PCI and the incidence of restenosis at follow-up angiography were evaluated. By means of OCT images, medial coronary dissection was defined as a dissection which reached the medial layer of the vessel, and major dissection was defined as a dissection with more than 60 degrees of the circumference of the vessel or more than 3mm in length. Restenosis was defined as more than 50% diameter stenosis evaluated by Quantitative Coronary Angiography.

Results

Restenosis was observed in 13 of 49 lesions (27%). In univariate logistic regression analysis, major dissection and medial dissection at the final OCT were associated with restenosis (Odds ratio [OR] 10.0; 95% confidence interval [CI] 2.5–52.6; p<0.01 and OR 5.8; 95% CI 1.5–25.1; p=0.01, respectively). Lesion preparation prior to DCB were performed with rotational atherectomy (n=9), orbital atherectomy (n=2), directional atherectomy (n=4), excimer laser angioplasty (n=17), scoring balloon angioplasty (n=13), or balloon angioplasty (n=4). OCT-defined major dissection remained a significant predictor for restenosis independent of debulking devices used for the preparation (OR 8.1; 95% CI 1.2–70.2; p=0.03).

Conclusions

Major dissection was associated with restenosis after non-stenting PCI with DCB. Stent implantation should be considered in cases of OCT-defined major dissection.

Acknowledgement/Funding

None

P5622Clinical significance of late-acquired malapposition observed by serial optical coherence tomography after second-generation drug eluting stents

Background

Previous studies have demonstrated that the presence of late-acquired stent malapposition after stent implantation may be a risk of late and very late stent thrombosis and myocardial infarction, which is however still controversial.

Purpose

We sought to investigate the incidence and prognosis of late acquired stent malapposion after second-generation drug eluting stents (2G-DES) implantation.

Methods

A total of 199 lesions in 139 patients who underwent optical coherence tomography (OCT) at both immediately after implantation (Baseline) and 6–12 months after 2G-DES implantation (follow-up) were investigated. We excluded lesions with stent failure before follow-up examination. We evaluated presence or absence of malapposed strut at 1mm interval of OCT images and stents with one or more cross-sections with >30% malapposed strut was defined as stents with malapposition (MP), otherwise well-apposed (WA). We divided the lesions into 4 groups according to the presence of malapposition at baseline and follow-up; WA and WA, persistent well-apposed; MP and WA, resoloved malapposition; WA and MP, late acquired malapposition (LAMP); and MP and MP, persistent malapposition. We compared the target lesion failure (TLF) rate after follow-up examination among 4 groups with Kaplan–Meier analysis.

Results

Median follow-up period was 469 (IQR 71–1416) days. follow-up OCT examination was performed at median 9 months (IQR 7.6–10.5). There were no significant differences in patient's and procedural characteristics among the 4 groups. TLF rate in LAMP group was 12.0% and Kaplan–Meier analysis showed no significant differences among the 4 groups in TLF rate.

TLF-free suvival curves (Kaplan-Meier)

Conclusion

LAMP was observed by OCT at 6–12 months in 12.0% of lesions after 2G-DES implantation, which was not associated with TLF at 5 years.

Extending coherence time of macro-scale diamond magnetometer by dynamical decoupling with coplanar waveguide resonator

Ultimate sensitivity for quantum magnetometry using nitrogen-vacancy (NV) centers in a diamond is limited by a number of NV centers and coherence time. Microwave irradiation with a high and homogeneous power density for a large detection volume is necessary to achieve a highly sensitive magnetometer. Here, we demonstrate a microwave resonator to enhance the power density of the microwave field and an optical system with a detection volume of 1.4 × 10^-3 mm³. The strong microwave field enables us to achieve 48 ns Rabi oscillation which is sufficiently faster than the phase relaxation time of NV centers. This system combined with a decoupling pulse sequence, XY16, extends the spin coherence time (T ₂) up to 27 times longer than that with a spin echo method. Consequently, we obtained an AC magnetic field sensitivity of 10.8 pt/ Hz using the dynamical decoupling pulse sequence.

Inchworm sign of endometrial cancer on diffusion-weighted MRI: radiology-pathology correlation

AIM

To perform radiology-pathology correlation of the inchworm sign on diffusion-weighted imaging (DWI) in patients with endometrial cancer.

MATERIALS AND METHODS

Consecutive patients (345) with histopathologically proven endometrial cancer who underwent preoperative magnetic resonance imaging (MRI), including DWI images, and hysterectomy were included in the present study. The inchworm sign was defined as a hypointense stalk between hyperintense endometrial cancer and hypointense myometrium on DWI images. A genitourinary pathologist reviewed the resected specimen at the site of the inchworm sign.

RESULTS

The inchworm sign on DWI images was observed in 32 (9.3%) patients. On T2-weighted images, areas of hypointense stalk on DWI images showed hypointensity in 31 (97%) patients and hyperintensity in one (3%). Among them, the depth of myometrial invasion at histopathology was superficial (<50% myometrial invasion) in 28 (87.5%) patients and deep (≥50% myometrial invasion) in four (12.5%). As a result of histopathological investigation, the hypointense stalk of the inchworm sign was mainly composed of various degrees of stromal proliferation, including smooth muscle cells and metaplastic fibromuscular stroma, with or without intervening endometrial cancer.

CONCLUSION

The inchworm sign of endometrial cancer on DWI images usually indicated superficial myometrial invasion and was caused by a stalk composed of stromal proliferation with or without intervening endometrial cancer.