Electron Temperature Measurements Using a Two-Filter Soft X-ray Array in VEST

A multichannel soft X-ray (SXR) array has been developed to measure the electron temperature in the Versatile Experiment Spherical Torus (VEST). To estimate electron temperature using the two-filter method applied to SXR intensity, we designed a pinhole camera that has two photodiode arrays with different metallic filters. We also adopted a filter wheel and tested various filter parameters to find the optimal filter set. Through tests, the combination of aluminum and beryllium was found to be the most suitable for the current experimental conditions in VEST. The filtered SXR signals were acquired with a low-noise preamplifier, exhibiting sufficient signal-to-noise ratios for electron temperature estimation based on the intensity ratio of two signals obtained with different filters. The estimated electron temperature from the developed two-filter SXR array showed reasonably matched levels and consistent trends with Thomson scattering measurements. Error contribution from impurity line emission is also discussed.

Development of a scintillator-based optical soft x-ray (OSXR) diagnostic system for KSTAR tokamak

We have developed a new scintillator-based optical soft x-ray (OSXR) diagnostic system for KSTAR. By utilizing fiber optic faceplates, mm-size lens arrays, and fiber bundles, we have successfully constructed a novel optical system for scintillator-based soft x-ray detection to overcome the limited vacuum-port conditions in KSTAR. P47 (Y2SiO5), which has a fast rise (∼7 ns) and decay (∼100 ns) time sufficient for detecting plasma instabilities observed in the kHz-MHz spectral range, was selected as the scintillator material for the KSTAR OSXR system. Scintillation toward each detection channel is collected by the lens arrays coupled to optical fiber cores, which are connected to the photodetector system. Initial results obtained during the 2022 KSTAR experimental campaign support the validity of the OSXR data through the consistency of OSXR measurement results with other diagnostics. We also observe that the OSXR system can capture magnetohydrodynamic activities, such as sawtooth oscillations, and provide valuable information for disruption mitigation studies using shattered pellet injection.

Development of a soft x-ray (SXR) array diagnostic system on versatile experiment spherical torus (VEST)

A new soft x-ray (SXR) array diagnostic system has been developed on versatile experiment spherical torus (VEST) for measurements of 2D SXR emissivity profile and identification of poloidal mode structure. Through tomographic inversion techniques, 2D SXR emissivity profile can be acquired from the line-integrated SXR data, which enables the visualization of mode structure of plasma instability, such as the magnetohydrodynamics mode. The SXR array diagnostic system consists of two 20-channel arrays positioned at the middle and the top on the same poloidal plane for horizontal and vertical lines of sight, respectively. Each array of the diagnostic system uses absolute extreme ultraviolet photodiode array as the detector. To apply appropriate filters (up to four) for different energy regimes without breaking the vacuum, a filter wheel and its rotatable vacuum feed-through are installed behind the pinhole. SXR data are acquired with a digitizer at the sampling rate of up to 125 MHz. Finally, we discuss initial measurement data obtained from Ohmic plasma in VEST.

Fast-ion Dα spectroscopy diagnostic at KSTAR

A fast-ion Dα (FIDA) diagnostics system was installed for core and edge measurements on KSTAR. This system has two tangential FIDA arrays that cover both blue- and redshifted Dα lines (cold: 656.09 nm) in active views along the neutral beam 1 A centerline. The spectral band is 647-662.5 nm, and it covers the Doppler shift of the emission from the maximum energy of the neutral beam (100 keV). A curved filter strip with a motorized stage adequately prevents saturation of the electron multiplying charge-coupled device signal by the cold Dα line from the plasma edge. From comparisons of the measured spectra and FIDASIM modeling code, the FIDA spectra are well matched quantitatively. Moreover, the first measurements show that the FIDA radiance agrees with the neutron rate in the time trace during external heating and perturbation. In addition, responses are observed in the core FIDA radiance during the edge-localized mode cycle.

Topically applied treatments for external genital warts in nonimmunocompromised patients: a systematic review and network meta-analysis

Selecting a topical treatment from among the numerous topical agents for external genital warts remains challenging without clear evidence. Our aim was to evaluate comparatively the efficacy and safety of topical agents for external genital warts using a network meta-analysis. We included all randomized controlled trials that evaluated any topically applied treatment for external genital warts. Using the R package netmeta, network meta-analyses were performed with a frequentist approach. We identified 41 relevant studies comprising 6371 patients. Among conventional agents, podophyllotoxin 0·5% solution (odds ratio 1·94, 95% confidence interval 1·02-3·71) was significantly more efficacious than imiquimod 5% cream for lesion clearance; however, it was associated with a higher overall adverse event rate. Sinecatechins 15% ointment (odds ratio 0·21, 95% confidence interval 0·12-0·34) was significantly less efficacious than imiquimod 5% cream. Idoxuridine, polyhexamethylene biguanide, cidofovir and SB206 showed comparable therapeutic efficacies with conventional therapies. None of the treatments were significantly different from each other with respect to recurrence, patients with severe adverse events, or patients who withdrew because of treatment-related adverse events. Conventional modalities were efficacious and well tolerated, although each of them had their advantages and disadvantages. Additional efficacy and safety studies are warranted for unconventional agents.

Radiofrequency ablation versus surgical resection for multiple HCCs meeting the Milan criteria: propensity score analyses of 10-year therapeutic outcomes

AIM

To assess the long-term therapeutic outcomes of radiofrequency ablation (RFA) versus surgical resection (SR) as a first-line treatment for patients meeting the Milan criteria with multiple hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and the requirement for informed consent was waived. Between January 2004 and December 2009, among 3,441 patients with treatment-naive HCCs, 88 patients meeting the Milan criteria with multiple HCCs (Barcelona Clinic Liver Cancer [BCLC] A stage) who underwent either RFA (n=62) or SR (n=26) were included. Recurrence-free survival (RFS) and overall survival (OS) rates were compared by using propensity score matching. In addition, multivariate analysis was performed for assess the prognostic factor.

RESULTS

Matching yielded 20 matched pairs of patients. In the two matched groups, the RFS rates were 30% and 30% at 5- and 10-years, respectively, in the RFA group and 60% and 48.6% in the SR group (p=0.054). The corresponding OS rates were 63.3% and 46.1% in the RFA group and 100% and 73.6% in the SR group, respectively (p=0.061). In multivariate analysis, treatment type was independently associated with RFS (hazard ratio [HR]=0.51; p=0.043) whereas it was not a statistically significant factor for OS (HR=0.50; p=0.088).

CONCLUSION

In patients meeting the Milan criteria with multiple HCCs (BCLC A stage), SR may provide better RFS compared to RFA.

Radiofrequency ablation and transarterial chemoembolisation as first-line treatment for recurrent hepatocellular carcinoma or isolated intrahepatic recurrent hepatocellular carcinoma in transplanted livers

AIM

To evaluate the efficacy of radiofrequency ablation (RFA) and transarterial chemoembolisation (TACE) as a first-line treatment for isolated intrahepatic recurrent hepatocellular carcinoma (IIR-HCC) after liver transplantation (LT).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. Between January 2005 and January 2015, 588 consecutive patients underwent LT for the treatment of HCC. Among them, 27 patients with IIR-HCCs after LT who were treated with RFA (n=6) or TACE (n=21) as a first-line treatment were retrospectively included in this study. Disease-free and overall survival rates were estimated using the Kaplan-Meier method. Risk factors affecting these outcomes were assessed with Cox regression models.

RESULTS

Except for the total number of recurrent tumours and time-to-tumour recurrence after LT, baseline characteristics were not significantly different between the groups. The 2-year disease-free survival rates for RFA and TACE (20% versus 14%, respectively; p=0.180) and 4-year overall survival rates (33% versus 25%, respectively; p=0.065) were not significantly different between groups. In addition, the types of treatment were not associated with disease-free or overall survival in multivariate analyses.

CONCLUSION

TACE may be an effective treatment comparable to RFA in patients with IIR-HCC after LT when RFA is not feasible.

A Study of Piezoelectric Field Related Strain Difference in GaN-Based Blue Light-Emitting Diodes Grown on Silicon(111) and Sapphire Substrates

We investigate the strain difference in InGaN/GaN multiple quantum wells of blue light-emitting diode (LED) structures grown on silicon(1 11) and c-plane sapphire substrates by comparing the strength of piezo-electric fields in MQWs. The piezo-electric fields for two LED samples grown on silicon and sapphire substrates are measured by using the reverse-bias electro-reflectance (ER) spectroscopy. The flat-band voltage is obtained by measuring the applied reverse bias voltage that induces a phase inversion in the ER spectra, which is used to calculate the strength of piezo-electric fields. The piezo-electric field is determined to be 1.36 MV/cm for the LED on silicon substrate and 1.83 MV/cm for the LED on sapphire substrate. The ER measurement results indicate that the strain-induced piezo-electric field is greatly reduced in the LED grown on silicon substrates consistent with previous strain measurement results by micro-Raman spectroscopy and high-resolution transmission electron microscopy.

A combination of excimer laser treatment and topical tacrolimus is more effective in treating vitiligo than either therapy alone for the initial 6 months, but not thereafter

BACKGROUND

There are insufficient data on the long-term outcome of a combination therapy that comprises phototherapy and topical administration of tacrolimus.

AIM

To evaluate the clinical efficacy according to the duration of treatment and in vitro results of a combination therapy involving topical tacrolimus and an excimer laser in the treatment of vitiligo.

METHODS

In total, 276 patients with nonsegmental vitiligo were treated with an excimer laser twice weekly, or with tacrolimus ointment twice daily, or both. The melanin contents and levels of melanogenic enzymes were measured in cultured human melanocytes treated with tacrolimus and/or excimer laser.

RESULTS

After adjusting for potential confounders, the combination of tacrolimus plus excimer laser was significantly more effective than either tacrolimus or excimer laser alone (P < 0.001 and P < 0.01, respectively) for the first 6 months. However, this superiority was not observed after the initial 6 months of treatment. In vitro, the combination of tacrolimus plus excimer laser led to a higher level of melanogenesis than with either treatment alone.

CONCLUSIONS

A combination treatment with topical tacrolimus and an excimer laser may be useful as an induction therapy for up to 6 months, but continuation of this therapy for > 6 months might not provide a better final outcome than monotherapy.

Comparison of Strain in GaN-Based Blue Light-Emitting Diode Grown on Silicon(111) and Sapphire Substrates

We compare the strain states and device performances of GaN-based blue light-emitting diodes (LEDs) grown on Si(111) and sapphire substrates. The strain characteristics are investigated using micro-Raman spectroscopy and high-resolution transmission electron microscopy. These analyses reveal that GaN layer grown on Si has a residual tensile strain in contrast to a compressive strain for GaN on sapphire, and quantum wells (QWs) on GaN/Si experience reduced lattice mismatch than those of GaN/sapphire. When external quantum efficiencies of LED on sapphire and Si substrates are compared, the LED on Si shows better efficiency droop characteristics and this is attributed to a decrease in piezo-electric field strength in InGaN/GaN layers owing to reduced lattice mismatch.

Hepatic radiofrequency ablation: in vivo and ex vivo comparisons of 15-gauge (G) and 17-G internally cooled electrodes

OBJECTIVE

To compare the performance of the 15-G internally cooled electrode with that of the conventional 17-G internally cooled electrode.

METHODS

A total of 40 (20 for each electrode) and 20 ablation zones (10 for each electrode) were made in extracted bovine livers and in in vivo porcine livers, respectively. Technical parameters, three dimensions [long-axis diameter (Dl), vertical-axis diameter (Dv) and short-axis diameter (Ds)], volume and the circularity (Ds/Dl) of the ablation zone were compared.

RESULTS

The total delivered energy was higher in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (8.78 ± 1.06 vs 7.70 ± 0.98 kcal, p = 0.033; 11.20 ± 1.13 vs 8.49 ± 0.35 kcal, p = 0.001, respectively). The three dimensions of the ablation zone had a tendency to be larger in the 15-G group than in the 17-G group in both studies. The ablation volume was larger in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (29.61 ± 7.10 vs 23.86 ± 3.82 cm(3), p = 0.015; 10.26 ± 2.28 vs 7.79 ± 1.68 cm(3), p = 0.028, respectively). The circularity of ablation zone was not significantly different in both the studies.

CONCLUSION

The size of ablation zone was larger in the 15-G internally cooled electrode than in the 17-G electrode in both ex vivo and in vivo studies.

ADVANCES IN KNOWLEDGE

Radiofrequency ablation of hepatic tumours using 15-G electrode is useful to create larger ablation zones.

Secondary cutaneous lymphoma: comparative clinical features and survival outcome analysis of 106 cases according to lymphoma cell lineage

BACKGROUND

The relative frequency, clinical features and survival outcomes of secondary cutaneous lymphoma remain poorly understood.

OBJECTIVES

To determine the clinical characteristics and survival outcomes of secondary cutaneous lymphoma.

MATERIALS AND METHODS

The present retrospective cohort study included all 106 patients who presented with secondary cutaneous lymphoma. Patient medical records were reviewed to determine the clinical features, survival outcomes and prognostic factors. Survival outcomes were analysed by using the Kaplan-Meier method and comparisons between lymphoma cell lineages [T or natural killer (T-/NK)-cell vs. B-cell lymphoma] were performed using the log-rank test.

RESULTS

Secondary cutaneous lymphomas consisted of mature T-/NK-cell lymphomas (56%), mature B-cell lymphomas (35%), immature haematopoietic malignancies (8%) and Hodgkin lymphoma (1%). The T-/NK-cell lineage lymphoma cases were more likely to have multiple and disseminated skin lesions than the B-cell lineage lymphoma cases. The lymphoma cell lineage did not significantly influence survival outcomes. Patients who showed cutaneous involvement within 6 months of the initial diagnosis of primary disease had a poorer overall survival (OS) outcome than patients who developed cutaneous dissemination 6 or more months after the initial diagnosis (P < 0.001). Patients with disseminated skin lesions had a poorer OS than patients with localized skin lesions (P = 0.028). The two lymphoma cell lineages differed in terms of prognostic factors that influenced survival.

CONCLUSIONS

Skin lesion characteristics such as time point of appearance and extent affect the survival outcomes of secondary cutaneous lymphoma. Cell lineage did not influence survival outcomes but the two lineages are associated with different prognostic factors.

B7-H1 inhibits T cell proliferation through MHC class II in human mesenchymal stem cells

B7-H1 on mesenchymal stem cells (MSCs) is known to modulate immune response. However, its expression pattern and exact immunomodulatory mechanism are unclear. In this study, we examined the immunomodulatory mechanism through the expression pattern of B7-H1 and major histocompatibility complex class II in various MSCs. Human bone marrow, adipose tissue, and cord blood MSCs were isolated and cultured. B7-H1, HLA-ABC, and HLA-DR expression on MSCs by interferon-γ (IFN-γ) was detected time-dependently by flow cytometry. The inhibitory effect of MSCs on T lymphocytes was observed in phytohemagglutinin antigen-induced T cell proliferation assay. The expression of B7-H1 was rapidly induced, but the expression of HLA-DR was induced at 48 hours after IFN-γ treatment. The inhibitory effect of MSCs on T cell proliferation could be restored when the anti-B7-H1 monoclonal antibody was used to block the B7-H1, or when the HLA-DRα small interfering RNA was used to interfere with its expression. These results show that MSCs could inhibit the T cell proliferation and activation by B7-H1 depending on the presence of HLA-DR. Therefore, MSCs would have a strong effect on immune diseases such as graft-versus-host disease and autoimmune diseases when MSCs are primed with IFN-γ 48 hours before transplantation.

Biodegradable and biocompatible soy protein/polymer/adhesive sticky nano-textured interfacial membranes for prevention of esca fungi invasion into pruning cuts and wounds of vines

Adhesive biodegradable membranes (patches) for the protection of pruning locations of plants from esca fungi attacks were developed using electrospun soy protein/polyvinyl alcohol and soy protein/polycaprolactone nanofibers. Several different water-soluble adhesives were either added directly to the electrospinning solutions or electrosprayed onto the as-spun nanofiber mats. The nanofibers were deposited onto a biodegradable rayon membrane, and are to be pressed onto the pruned location on a plant. The pore size in the nanofiber mats is sufficient for physically blocking fungi penetration, while the outside rayon membrane provides sufficient mechanical support in handling prior to deposition on a plant. Diseases like Vine Decline are one of the most important cases where such a remedy would be needed. It should be emphasized that these novel biodegradable and sticky patches are radically different from the ordinary electrospun ultra-filtration membranes. The normal and shear specific adhesive energy of the patches were measured, and the results show that they can withstand strong wind without being blown off. On the other hand, the patches possess sufficient porosity for plant breathing.

Percutaneous ultrasonography-guided radiofrequency ablation of hepatocellular carcinomas: usefulness of image fusion with three-dimensional ultrasonography

AIM

To evaluate the usefulness of fusion imaging with real-time ultrasonography (US) and three-dimensional (3D) US for the guidance of radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) 2-5 cm in diameter.

MATERIALS AND METHODS

This study was conducted as a retrospective cohort study. It was approved by the institutional review board and informed consent was waived. During percutaneous RFA of HCCs, targeting was performed under conventional fusion imaging guidance, whereas monitoring and controlling were conducted under fusion with 3D US guidance. Technical success, technique effectiveness, incidence of major complications, and local tumour progression rate were evaluated. According to tumour size (small: <3 cm versus medium: 3-5 cm), the roundness indexes of the ablation zones and local tumour progression rates were compared.

RESULTS

There were 29 small-sized HCCs (2.5 ± 0.3 cm) and 17 medium-sized HCCs (3.4 ± 0.5 cm). All RFA procedures were performed in a single RFA session. Both the technical success and technique effectiveness rates were 100%. One patient with medium-sized HCC developed a hepatic abscess (n = 1) as a major complication. The local tumour progression rate was 8.7% (4/46) with a mean follow-up period of 18.2 months. The roundness indexes of the ablation zone were not significantly different between small- and medium-sized HCCs, and the local tumour progression rates were also not significantly different between the two groups [3.4% (1/29) versus 17.6% (3/17); p = 0.135].

CONCLUSION

Image fusion with real-time US and 3D US is useful for the guidance of percutaneous RFA for HCCs 2-5 cm in diameter.

Comparison of therapeutic efficacy and safety of radiofrequency ablation of hepatocellular carcinomas between internally cooled 15-G and 17-G single electrodes

OBJECTIVE

To compare the ablation volume, local tumour progression rate and complication rate of radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) using 15-G and 17-G single electrodes.

METHODS

This retrospective study was approved by the institutional review board and informed consent was waived. We reviewed percutaneous RFA cases for HCCs using 15-G or 17-G electrodes without multiple overlapping ablations. A total of 36 pairs of HCCs matched according to tumour size and active tip length were included. We compared ablation volume and complication rate between the two electrode groups. Cumulative local tumour progression rates were estimated using the Kaplan–Meier method and compared using the log-rank test.

RESULTS

Tumour size and ablation time were not significantly different between the 15-G and 17-G groups (p50.661 and p50.793, respectively). However, ablation volume in the 15-G electrode group was larger than that in the 17-G group (14.465.4cm3 vs 8.762.5cm3; p,0.001). No statistical difference in complication rates between the two electrode groups was found. The 10- and 20-month local tumour progression rates were not significantly different between the two groups (2.8% and 5.6% vs 11.1% and 19.3%; p50.166).

CONCLUSION

Ablation volume by the 15-G electrode was larger than that by the 17-G electrode. However, local tumour progression rate and complication rate were not significantly different between the two electrode groups.

ADVANCES IN KNOWLEDGE

RFA of HCC using a 15-G electrode is useful to create larger ablation volumes than a 17-G electrode.

Environmental variabilities and the distribution of octocorals and black corals in Hong Kong

A recent comprehensive survey covering 125 sites in Hong Kong waters recorded 29 soft coral species in 14 genera, 38 species of gorgonians in 19 genera and six species of black corals in two genera. Environmental variabilities based on water quality data collected by Hong Kong Environmental Protection Department were analyzed using multivariate statistics to find variables that are significantly correlated with coral distribution patterns. Eleven water quality zones with similar environmental variabilities were recognized, which could further be classified into five groups, namely Inner Bay, Outer Bay, Eastern, Western and Southern waters. LINKTREE analysis provided an overall trend indicating the importance of salinity, sediment and nutrient loadings in affecting octocoral and black coral distribution from west to east of Hong Kong waters, and from inner to outer bays. Furthermore, water turbidity and wave exposure could also affect the coral distribution patterns from north, northeast to southern waters.

Percutaneous radiofrequency ablation of hepatic tumours: factors affecting technical failure of artificial ascites formation using an angiosheath

AIM

To evaluate the technical feasibility of artificial ascites formation using an angiosheath before percutaneous radiofrequency ablation (RFA) for hepatic tumours and to determine predictive factors affecting the technical failure of artificial ascites formation.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. One hundred and thirteen patients underwent percutaneous RFA of hepatic tumours after trying to make artificial ascites using an angiosheath to avoid collateral thermal damage. The technical success rate of making artificial ascites using an angiosheath and conversion rate to other techniques after initial failure of making artificial ascites were evaluated. The technical success rate for RFA was assessed. In addition, potential factors associated with technical failure including previous history of transcatheter arterial chemoembolization (TACE) or RFA, type of abdominal surgery, and adjacent perihepatic structures were reviewed. Predictive factors for the technical failure of artificial ascites formation were analysed using multivariate analysis.

RESULTS

The technical success rates of artificial ascites formation by angiosheath and that of RFA were 84.1% (95/113) and 97.3% (110/113), respectively. The conversion rate to other techniques after the failure of artificial ascites formation using an angiosheath was 15.9% (18/113). Previous hepatic resection was the sole independent predictive factor affecting the technical failure of artificial ascites formation (p<0.001, odds ratio = 29.03, 95% confidence interval: 4.56-184.69).

CONCLUSION

Making artificial ascites for RFA of hepatic tumours using an angiosheath was technically feasible in most cases. However, history of hepatic resection was a significant predictive factor affecting the technical failure of artificial ascites formation.

Upper abdominal gadoxetic acid-enhanced and diffusion-weighted MRI for the detection of gastric cancer: Comparison with two-dimensional multidetector row CT

AIM

To evaluate the diagnostic performance of abdominal magnetic resonance imaging (MRI) for the detection of gastric cancer in comparison with that of two-dimensional (2D) multidetector row computed tomography (CT).

MATERIALS AND METHODS

The study included 189 patients with 170 surgically confirmed gastric cancers and 19 patients without gastric cancer, all of whom underwent gadoxetic acid-enhanced MRI with diffusion-weighted (DW) imaging, and multidetector contrast-enhanced abdominal CT imaging. Two observers independently analysed three sets of images (CT set, conventional MRI set, and combined conventional and DW MRI set). A five-point scale for likelihood of gastric cancer was used. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were evaluated. Quantitative [apparent diffusion coefficient (ADC) analyses with Mann-Whitney U-test were conducted for gastric cancers and the nearby normal gastric wall.

RESULTS

The diagnostic accuracy and sensitivity for detection of gastric cancer were significantly higher on combined conventional and DW MRI set (77.8-78.3%; 75.3-75.9%) than the CT imaging set (67.7-71.4%; 64.1-68.2%) or the conventional MRI set (72-73%; 68.8-70%; p < 0.01). In particular, for gastric cancers with pT2 and pT3, the combined conventional and DW MRI set (91.6-92.6%) yielded significantly higher sensitivity for detection of gastric cancer than did the CT imaging set (76.8-81.1%) by both observers (p < 0.01). The mean ADC of gastric cancer lesions (1 ± 0.23 × 10(-3) mm(2)/s) differed significantly from that of normal gastric wall (1.77 ± 0.25 × 10(-3) mm(2)/s; p < 0.01).

CONCLUSION

Abdominal MRI with DW imaging was more sensitive for the detection of gastric cancer than 2D-multidetector row CT or conventional MRI alone.