From Solution to Thin Film: Molecular Assembly of π-Conjugated Systems and Impact on (Opto)electronic Properties.

The assembly of conjugated organic molecules from solution to solid-state plays a critical role in determining the thin film morphology and optoelectronic properties of solution-processed organic electronics and photovoltaics. During evaporative solution processing, π-conjugated systems can assemble via various forms of intermolecular interactions, forming distinct aggregate structures that can drastically tune the charge transport landscape in the solid-state. In blend systems composed of donor polymer and acceptor molecules, assembly of neat materials couples with phase separation and crystallization processes, leading to complex phase transition pathways which govern the blend film morphology. In this review, we provide an in-depth review of molecular assembly processes in neat conjugated polymers and nonfullerene small molecule acceptors and discuss their impact on the thin film morphology and optoelectronic properties. We then shift our focus to blend systems relevant to organic solar cells and discuss the fundamentals of phase transition and highlight how the assembly of neat materials and processing conditions can affect blend morphology and device performance.

Diagnostic assessments and treatment results of well-differentiated gastric-type adenocarcinoma of the uterine cervix (Adenoma malignum): A multicenter retrospective analysis of KROG 22-03 study.

OBJECTIVE: Among cervical adenocarcinomas, well-differentiated gastric adenocarcinoma of the uterine cervix (WD-GAS), previously termed adenoma malignum (minimal deviation adenocarcinoma) is not well understood. Because of its rarity and difficulty in diagnosis, there is no standard care for WD-GAS. Thus, we conducted the first multicenter retrospective study on WD-GAS to clarify prognostic factors for long-term survival and recurrence. METHODS: Patients diagnosed with WD-GAS at eight hospitals participated in this multi-center study. Overall survival (OS) and recurrence-free survival (RFS) were calculated with the Kaplan-Meier method. Additionally, OS between the early and advanced FIGO stage groups were compared with the log-rank test. Cox regression analysis was conducted to identify significant factors associated with recurrence-free survival (RFS). RESULTS: A total of 73 patients from eight hospitals in South Korea were included in the analysis. The median follow-up period was 44.8 months, and all patients underwent curative surgical intervention as the primary treatment. Recurrence was observed in 17 patients (23.3%). Ten patients had locoregional recurrence, four patients had distant metastasis, and three patients presented with both locoregional recurrence and distant metastasis. The Cox regression analysis identified several statistically significant factors associated with RFS, including vaginal invasion (VI), parametrial invasion (PMI), resection margin (RM), and nodal and lymphovascular invasion (LVI). When considering these five factors together, patients without any of the factors exhibited recurrence-free survival (RFS) of 97.0% at three years and those with more than one of these factors had a 3-year RFS of 65.4% (P < 0.001). CONCLUSION: WD-GAS showed relatively high locoregional recurrence rate. Positive PMI, VI, RM, nodal involvement, and LVI were associated with a significant increase in recurrence or distant metastasis rates.

MRI-based volumetric tumor parameters before and during chemoradiation predict tumor recurrence and patient survival in locally advanced cervical cancer: a subgroup analysis of a phase II prospective trial.

BACKGROUND: This subgroup analysis of a prospective phase II trial aimed to identify valuable and accessible prognostic factors for overall survival (OS) and progression-free survival (PFS) of patients with locally advanced cervical cancer (LACC). METHODS: Patients with FIGO II to IVA cervical cancer were assessed in this study. All patients underwent concurrent chemoradiotherapy (CCRT) followed by brachytherapy. Tumor parameters based on MRI scans before and during CCRT were evaluated for Overall survival (OS) and Progression-free survival (PFS). RESULTS: A total of 86 patients were included in this analysis with a median follow-up period of 31.7 months. Three-year OS and PFS rates for all patients were 87.1% and 76.5%, respectively. Univariate Cox regression analysis showed that restaging tumor size (rTS) over 2.55 cm (p < 0.001), initial tumor volume (iTV) over 55.99 cc (p < 0.001), downstaging (p = 0.042), and restaging tumor volume (rTV) over 6.25 cc (p = 0.006) were significantly associated with OS. rTS (p < 0.001), iTV (p < 0.001), downstaging (p = 0.027), and rTV (p < 0.001) were identified as significant prognostic factors for PFS. In the stepwise multivariable analysis, only rTS > 2.55 cm showed statistically significant with OS (HR: 5.47, 95% CI 1.80-9.58, p = 0.035) and PFS (HR: 3.83, 95% CI 1.50-11.45; p = 0.025). CONCLUSIONS: Initial tumor size and restaging tumor volume that are easily accessible during radiotherapy provide valuable prognostic information for cervical cancer. MRI-based measurable volumetric scoring system can be readily applied in real-world practice of cervical cancer. CLINICAL TRIAL INFORMATION: This study is a subgroup analysis of prospective trial registered at ClinicalTrials.gov Identifier: NCT02993653.

High-dose (60 Gy) intensity-modulated radiotherapy with concurrent weekly cisplatin followed by intracavitary radiation in locally advanced cervical cancer: A phase II prospective clinical trial.

OBJECTIVE: Radiotherapy dose-escalation using intensity-modulated radiotherapy (IMRT) has been necessary to improve treatment results in cervical cancer. METHODS: This was a phase II prospective clinical trial. 88 patients with FIGO II-IVa cervical cancer were enrolled in a single center. They received high-dose (60 Gy) IMRT with weekly cisplatin to the primary tumor and clinically positive nodes followed by intracavitary radiation. The primary endpoint was 30-month PFS rate (Target; 82%, an increase of 20% compared to GOG 120 trial using standard-dose radiotherapy). Secondary endpoints were tumor response, toxicity, recurrence, distant metastasis, and overall survival. RESULTS: Progression-free survival rate at 30 months was 82.8%. Overall survival, locoregional recurrence, distant metastasis, and para-aortic recurrence rates at 30 months were 93.6%, 8.2%, 9.2%, and 2.4%, respectively. Forty-five (51.1%) of 88 patients achieved downstaging on MRI during radiotherapy and 80 (90.9%) patients had clinically complete response at three months after high-dose IMRT and intracavitary radiotherapy. The 30-month recurrence-free survival (92.9% vs. 73.1%, P = 0.009) and overall survival (100% vs. 87.0%, P = 0.006) were significantly higher in the downstaged group than in the non-downstaged group during radiotherapy. Grade 3 or higher hematologic toxicity was found in 11 (12.5%) patients and grade 3 or higher non-hematologic toxicity was found in 3 (3.4%) patients. Fourteen had chronic urinary (8.0%), intestinal (5.7%) toxicity, pelvic insufficiency fracture (2.3%) or vesicovaginal fistula (2.3%). CONCLUSION: High-dose (60 Gy) IMRT with concurrent weekly cisplatin in locally advanced cervical cancer yielded favorable progression-free survival outcome. Tumor response during radiotherapy can be a significant prognostic factor for PFS. CLINICAL TRIAL INFORMATION: This prospective trial is registered at ClinicalTrials.gov Identifier: NCT02993653.

Insights of Peculiar Green-Yellow Emission Occurrence in Ce3+-Doped Barium Yttrium Orthogermanate Phosphors.

The Ba8.8Ce0.1Na0.1Y2Ge6O24 orthogermanate phosphor, prepared by LiCl flux assistance under a reducing atmosphere, exhibited a mysterious green-yellow emission at 298 K. A blue-emitting orthogermanate phosphor was expected to be achieved through the lower d-band of Ce3+ ions in the host structure owing to their optical structure geometry. Oxygen vacancies were observed in the phosphors through investigating bond-length fluxations, the oxygen 1s profile, and the Ge2+/Ge4+ oxidation state, using synchrotron X-ray diffraction refinement, X-ray photoelectron spectroscopy, and Ge K-edge X-ray absorption near-edge structure spectra, respectively. The Ba-M4,5 edge shift, bonding limitation, and distortion index discovery reveal the oxygen-coordinating environment variation around the Ba2+(Ce3+) ions in the phosphors. The green-yellow emission results from the active 6-coordinated antiprism oxygen geometry around the Ce3+ ions in the phosphors.

The effect of biological agent on body composition in patients with Crohn's disease.

BACKGROUND: Crohn's disease (CD) is associated with altered body composition, affecting clinical outcomes. We evaluated the impact of biologics on body composition in CD patients. METHODS: This multicenter longitudinal study across four Korean university hospitals conducted from January 2009 to August 2021 retrospectively reviewed data of CD patients with abdominal computed tomography (CT) before and after the biologic treatment. Skeletal muscle area (SMA), visceral fat area (VFA), and subcutaneous fat area (SFA) of the third lumbar vertebra (L3) on CT were measured. Myopenia was defined as L3 skeletal muscle index (SMI) of < 49 and < 31 cm2/m2 for men and women, respectively. RESULTS: Among 112 participants, 79 (70.5%) had myopenia. In the myopenia group, all body composition parameters were significantly increased after the biologic treatment: SMI (37.68 vs. 39.40 cm2/m2; P < 0.001), VFA (26.12 vs. 54.61 cm2; P < 0.001), SFA (44.29 vs. 82.42 cm2; P < 0.001), while no significant differences were observed in the non-myopenia group. In multivariate analysis, penetrating CD (hazard ratio, 5.40; P = 0.020) was the independent prognostic factor for surgery. Operation-free survival rate tended to decrease in the myopenia group (Log-rank test, P = 0.090). CONCLUSIONS: Biological agents can increase all body composition parameters in CD patients with myopenia. These patients are more likely to experience surgery.

Clinical outcomes and risk factors associated with poor prognosis after endoscopic resection of 10-20 mm rectal neuroendocrine tumors: a multicenter, retrospective study of 10-year experience.

BACKGROUND: The efficacy of endoscopic resection for of 10-20 mm rectal neuroendocrine tumor (NET) remains controversial. We aimed to evaluate the clinical outcomes and risk factors associated with poor prognosis after endoscopic resection of 10-20 mm rectal NET and to determine the optimal treatment. METHODS: Patients who underwent endoscopic resection for rectal NET in four tertiary hospitals were enrolled, and data on with the clinical outcomes and risk factors related to poor prognosis were retrospectively analyzed. RESULTS: A total of 105 patients who underwent endoscopic submucosal resection (ESD; n = 65, 61.9%), modified endoscopic mucosal resection (mEMR; n = 31, 29.5%), and conventional EMR (cEMR; n = 9, 8.6%) were enrolled. The mean follow-up period was 41.2 ± 21.9 months. In the morphologic findings, the mean diameter was 11.6 mm (range 10-19); the shape was sessile (50.5%) and mixed type (49.5%), and surface depression was observed in 41.9% of patients. In the histologic findings, 87.6% of patients had G1 and 12.4% G2 tumor grade, and 3.8% of patients had lymphovascular invasion. The overall en bloc and histologically complete (R0) resections were 99.1% and 76.2%, respectively. cEMR was a less-frequently developed R0 resection. In the univariate and multivariate analyses for R0 resection, only surface depression was significantly associated. Regional or distant organs metastasis during follow-up developed in three patients (2.9%) and was significantly associated with female sex, redness, G2 tumor grade, and non-ESD methods. CONCLUSION: Patients who underwent endoscopic resection of 10-20 mm rectal NET had good prognosis; therefore, endoscopic resection can be considered as the first-line treatment, particularly for 10-14 mm rectal NET. However, the risk factors, such as female sex, redness, G2 tumor grade and non-ESD methods, were associated with regional or distant metastases during follow-up. Therefore, patients with these risk factors should be carefully monitored.

Spontaneous resolution of long-standing choroidal effusion after glaucoma drainage implant surgery without significant visual deterioration : a case report.

BACKGROUND: Choroidal effusion is a common complication of glaucoma surgery. Although most cases of choroidal effusions resolve spontaneously with observation or medical management alone as intraocular pressure normalizes, surgical drainage might be needed in severe or persistent cases. Herein, we report a case of spontaneous resolution of long-standing severe choroidal effusion after Ahmed glaucoma valve implantation. CASE PRESENTATION: An 85-year-old man with uncontrolled primary open-angle glaucoma and medical history of chronic kidney disease underwent uneventful Ahmed glaucoma valve implantation. On postoperative day 8, transient hypotony occurred, and large 360° peripheral choroidal detachments developed. Although the intraocular pressure increased to normal levels on postoperative day 15, choroidal effusion did not resolve. Fundus examination over 8 months showed that the large choroidal effusion persisted despite a well-controlled intraocular pressure. Laboratory test performed at preoperatively and follow-up period revealed persistently elevated potassium and creatinine levels. On postoperative 9 months, the lesion resolved spontaneously without any surgical intervention. We found that the patient's creatinine level was normalized, pre-existing hyperkalemia was corrected, and accordingly his general condition was improved. CONCLUSIONS: Considering the underlying medical condition may be helpful in patients with persistent choroidal effusion of an unclear etiology following glaucoma filtering surgery.

Randomized multicenter phase II trial of prophylactic irradiation of para-aortic lymph nodes in advanced cervical cancer according to tumor hypoxia: Korean Radiation Oncology Group (KROG 07-01) study.

We conducted a prospective phase II study on whether extended-field irradiation (EFI) confers survival benefits depending on hypoxic markers in locally advanced uterine cervical cancer (LAUCC). RNA-seq was performed to identify immune and hypoxic gene signatures. A total of 288 patients were randomized to either EFI or pelvic radiotherapy (PRT). All patients completed chemoradiotherapy. Overall, significantly higher 5-year para-aortic recurrence free survival (PARFS) rate occurred in EFI (97.6%) than in PRT group (87.2%), with marginal tendency to improve disease-free survival (DFS; 78% vs 70%, P = .066). Subgroup analyses were performed based on carbonic anhydrase 9 (CA9)-only positive, CA9/hypoxia-inducible factor (HIF) double positive and CA9 negative. In the CA9-only positive, EFI successfully increased 5-year PARFS (100% vs 76.4%, P = .010), resulting in significantly improved long-term DFS (85.7% vs 54.7%, P = .023) compared to the PRT, while there was no such benefit of EFI in the CA9/HIFs double positive. RNA-seq analysis identified distinct immunehigh subgroup with negative correlation with hypoxia gene signatures (R = -.37, P < .01), which showed a higher 5-year DFS than the immunelow (P = .032). Hypoxia-related genes were upregulated in the CA9/HIFs double positive compared to CA9 negative (P < .05). Only 17.4% of patients in CA9-negative group showed immunelow signatures, while 40.0% of patients in the double-positive group exhibited immunelow signatures. In conclusion, EFI improved PARFS significantly in all patients, but therapeutic efficacy of EFI in terms of improved DFS was solely observed in CA9-only positive LAUCC, and not in CA9/HIFs double-positive subgroup. RNA-seq analysis suggested that hypoxia-induced immunosuppression may be related to treatment resistance in LAUCC.

The impact of face shields on the quality of gastrointestinal endoscopy during the COVID-19 pandemic.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has become a global pandemic, with healthcare workers at a high risk of exposure. During this pandemic, endoscopists must wear personal protective equipment (PPE), including face shields, to prevent COVID-19 transmission; however, few studies have reported the impact of face shields on the quality of gastrointestinal (GI) endoscopy. We aimed to determine whether the use of PPE, including face shields, affected the quality of GI endoscopy during the COVID-19 pandemic. METHODS: The medical records of patients who had undergone screening or surveillance colonoscopy and gastric endoscopic submucosal dissection (ESD) at Dong-A University Hospital between June 2020 and March 2021 were retrospectively reviewed. Endoscopists wore isolation gowns, disposable gloves, and KF94 masks from June 2020 to October 2020. From November 2020, endoscopists also wore face shields. We compared GI endoscopy quality indicators between the first five months (no face shields) and the second five months (with face shields). In the non-face shield and face shield groups, we calculated the overall adenoma detection rates (ADRs), polyp detection rate (PDR), sessile serrated lesion detection rate (SSLDR), advanced neoplasia detection rate (ANDR), complete resection rate (CRR), number of polyps and/or adenomas per colonoscopy, and gastric ESD procedure time. RESULTS: In total, 1359 study patients had undergone screening or surveillance colonoscopy (face shield group, n = 679; non-face shield group, n = 680). No statistically significant between-group differences were observed (PDR, 49.04 vs. 52.50%, p = 0.202; ADR, 38.59 vs. 38.97%, p = 0.884; SSPDR, 1.91 vs. 1.32%, p = 0.388; ANDR, 3.98 vs. 3.97%, p = 0.991, respectively). No difference was found in colonoscopy quality indicators between patients examined by experienced and trainee endoscopists with and without face shields. Of 144 study patients who had undergone gastric ESD for gastric neoplasms, there were 72 patients in each group. No statistically significant differences were found in the CRR (94.44 vs 93.05%, p = 1.000) and procedure times (19.22 ± 9.33 vs. 19.03 ± 11.49, p = 0.911). CONCLUSIONS: Wearing face shields during the COVID-19 pandemic did not affect the quality indicators for GI endoscopy.

Oxaliplatin-based adjuvant chemotherapy rather than fluorouracil-based chemotherapy in rectal cancer is more efficient to decrease distant metastasis and increase survival after preoperative chemoradiotherapy and surgery: a meta-analysis.

PURPOSE: The standard treatment of stage II-III rectal cancer is preoperative chemoradiotherapy (CRT), followed by total mesorectal excision (TME). However, the rate of metastasis is still high following this treatment. Therefore, several adjuvant chemotherapy studies have been conducted on reducing subsequent metastases and increasing survival, although there are still no definite conclusions. METHODS: We searched for published prospective randomized controlled trials comparing adjuvant chemotherapy regimens following standard preoperative CRT and curative surgery in stage II-III rectal cancer. We systematically searched Medline, Embase, and the Cochrane Library for relevant trials done from January 2004 to January 2021. Review Manager (RevMan, version 5.3) was used to analyze the data. RESULTS: We initially searched 1955 studies. We screened and carefully selected four randomized controlled trials with 2897 patients. Compared to the 5-FU-based regimen group, the oxaliplatin-added regimen group attained a higher 3-year locoregional control rate (relative risk [RR] of 0.64, 95% confidence interval [CI], 0.48-0.86; p = 0.003) and 3-year distant metastasis control rate (RR of 0.82, 95% CI, 0.71-0.95; p = 0.007). The oxaliplatin-added regimen group had significantly increased 3-year disease-free survival with a hazard ratio (HR) of 0.85 (95% CI: 0.74-0.97, p = 0.020), but not overall survival (p = 0.740). Grade 3 or higher acute toxicity rates did not differ between the two groups (p = 0.190). CONCLUSION: The addition of oxaliplatin to adjuvant therapy for stage II-III rectal cancer following preoperative CRT and TME may increase disease-free survival without significant increases in toxicity, but not overall survival.

Stereotactic ablative radiotherapy for pulmonary oligometastases from primary hepatocellular carcinoma: a multicenter and retrospective analysis (KROG 17-08).

OBJECTIVE: Hypofractionated radiotherapy has recently been applied to treat pulmonary metastases of hepatocellular carcinoma. However, there is no definite evidence on its safety and efficacy. We evaluate the clinical outcomes of hypofractionated radiotherapy for oligo pulmonary metastases of hepatocellular carcinoma in the multicenter and retrospective study. METHODS: From March 2011 to February 2018, 58 patients with fewer than five pulmonary metastases of hepatocellular carcinoma who underwent hypofractionated radiotherapy in nine tertiary university hospitals were analyzed retrospectively. The primary endpoint was the local control rate. The secondary endpoints were overall survival, progression-free survival, prognostic factors affecting the treatment outcomes and treatment-related side effects. RESULTS: The local tumor response rate including complete and partial response was 77.6% at 3 months after hypofractionated radiotherapy. The median survival and progression-free survival times were 20.9 and 5.3 months, respectively. The 1-year overall survival and progression-free survival rates were 65.5 and 22.4%, respectively. The good treatment response after hypofractionated radiotherapy (P = 0.001), the absence of intrahepatic tumor (P = 0.004) and Child-Pugh class A (P = 0.010) were revealed as significant prognostic factors for overall survival in the multivariate analysis. A progression-free interval of <6 months (P = 0.009) was a negative prognostic factor for overall survival in the multivariate analysis. Of 58 patients, five (8.6%) had grade 2 or higher radiation pneumonitis after hypofractionated radiotherapy. CONCLUSIONS: The favorable local control rate and acceptable toxicity indicate the clinical usefulness of hypofractionated radiotherapy for hepatocellular carcinoma patients who have less than five pulmonary metastases.

Comparison of treatment outcomes of pelvis external radiotherapy with and without vaginal brachytherapy for cervical cancer patients with positive or close vaginal resected margins.

BACKGROUND: We evaluated whether there is a difference in the local recurrence and survival after pelvic external radiotherapy (ERT) with and without boost vaginal brachytherapy (VB) in cervical cancer patients with positive or close vaginal resected margins (RM). METHODS: We retrospectively reviewed FIGO stage IA-IIB cervical cancer patients treated with postoperative ERT between 1997 and 2018. The sixty patients showing close (safety margin < 5 mm) or positive vaginal RM were included. ERT was delivered with median 50.4 Gy in 28 fractions to the pelvis and VB with median 30 Gy in 6 fractions. RESULTS: The median follow-up duration was 46 months. Five out of 30 patients treated with ERT alone experienced vaginal recurrence within 2 years after surgery. The 5-year local control (LC) was 100% in patients receiving ERT + VB compared with 81.3% in patients receiving ERT alone (log rank p = 0.022). The 5-year pelvic control (PC) was 95.8% for patients receiving ERT + VB and 76.8% for ERT alone (p = 0.041). The 5-year overall survival and recurrence-free survival (RFS) were not significantly different between treatment groups. In multivariate analysis, perineural invasion was a significant risk factor for PC (p = 0.024). Parametrial involvement (p = 0.044) and vascular invasion (p = 0.032) were unfavorable prognostic factors for RFS. Late toxicity occurrences were not significant in both groups. CONCLUSION: VB after ERT improved LC and PC in cervical cancer patients with close or positive RM after hysterectomy. The toxicities were not increased after VB was added to ERT.

mRNA COVID-19 Vaccine-Associated Subserosal Eosinophilic Gastroenteritis: A Case Report.

The World Health Organization declared coronavirus disease 2019 (COVID-19) a global pandemic in March 2020. Several vaccines have been developed to overcome the COVID-19 pandemic, and messenger RNA vaccines, commonly known as mRNA vaccines, were the first COVID-19 vaccines to be authorized in Korea. With the worldwide increase in vaccinations, reports of adverse reactions are increasing. However, to the best of our knowledge, there have been no reports of eosinophilic gastroenteritis (EGE) following mRNA vaccination. Here, we present the first case of EGE in a patient who received a second dose of the mRNA vaccine, BNT162b2 (Pfizer-BioNTech). A previously healthy 34-year-old woman presented to the emergency department with generalized abdominal pain for the preceding 2 weeks. She had received a second dose of the mRNA COVID-19 vaccine 2 weeks prior. Subserosal EGE was diagnosed, oral prednisolone was administered, and she recovered completely.

COVID-19 Molecular Pathophysiology: Acetylation of Repurposing Drugs.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces immune-mediated type 1 interferon (IFN-1) production, the pathophysiology of which involves sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1) tetramerization and the cytosolic DNA sensor cyclic-GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. As a result, type I interferonopathies are exacerbated. Aspirin inhibits cGAS-mediated signaling through cGAS acetylation. Acetylation contributes to cGAS activity control and activates IFN-1 production and nuclear factor-κB (NF-κB) signaling via STING. Aspirin and dapsone inhibit the activation of both IFN-1 and NF-κB by targeting cGAS. We define these as anticatalytic mechanisms. It is necessary to alleviate the pathologic course and take the lag time of the odds of achieving viral clearance by day 7 to coordinate innate or adaptive immune cell reactions.

The role of adaptation in generating monotonic rate codes in auditory cortex.

In primary auditory cortex, slowly repeated acoustic events are represented temporally by the stimulus-locked activity of single neurons. Single-unit studies in awake marmosets (Callithrix jacchus) have shown that a sub-population of these neurons also monotonically increase or decrease their average discharge rate during stimulus presentation for higher repetition rates. Building on a computational single-neuron model that generates stimulus-locked responses with stimulus evoked excitation followed by strong inhibition, we find that stimulus-evoked short-term depression is sufficient to produce synchronized monotonic positive and negative responses to slowly repeated stimuli. By exploring model robustness and comparing it to other models for adaptation to such stimuli, we conclude that short-term depression best explains our observations in single-unit recordings in awake marmosets. Together, our results show how a simple biophysical mechanism in single neurons can generate complementary neural codes for acoustic stimuli.

Microstructural evolution in self-catalyzed GaAs nanowires during in-situ TEM study.

The microstructural evolutions in self-catalyzed GaAs nanowires (NWs) were investigated by using in situ heating transmission electron microscopy (TEM). The morphological changes of the self-catalyst metal gallium (Ga) droplet, the GaAs NWs, and the atomic behavior at the interface between the self-catalyst metal gallium and GaAs NWs were carefully studied by analysis of high-resolution TEM images. The microstructural change of the Ga-droplet/GaAs-NWs started at a low temperature of ∼200 °C. Formation and destruction of atomic layers were observed at the Ga/GaAs interface and slow depletion of the Ga droplet was detected in the temperature range investigated. Above 300 °C, the evolution process dramatically changed with time: The Ga droplet depleted rapidly and fast growth of zinc-blende (ZB) GaAs structures were observed in the droplet. The Ga droplet was completely removed with time and temperature. When the temperature reached ∼600 °C, the decomposition of GaAs was detected. This process began in the wurtzite (WZ) structure and propagated to the ZB structure. The morphological and atomistic behaviors in self-catalyzed GaAs NWs were demonstrated based on thermodynamic considerations, in addition to the effect of the incident electron beam in TEM. Finally, GaAs decomposition was demonstrated in terms of congruent vaporization.

Latest Generation High-Definition Colonoscopy Increases Adenoma Detection Rate by Trainee Endoscopists.

BACKGROUND: Adenoma detection rate (ADR) is an important quality indicator of colonoscopy. High-definition (HD) colonoscopy has been reported to increase ADR compared to standard-definition (SD) colonoscopy. Although there are few reports comparing the latest generation and the previous generation of HD colonoscopy equipment, there are reports that the latest generation colonoscopy equipment improves ADR. However, there are no reports on the impact of the latest generation HD colonoscopy on the ADR of trainee endoscopists. AIMS: The aim of this study was to investigate whether the latest generation HD colonoscopy increases the ADR of trainee endoscopists compared with the previous generation HD colonoscopy. METHOD: We conducted a retrospective review of medical records of patients aged 40-79 years old, who underwent screening or surveillance colonoscopy performed by nine gastroenterology fellows at Dong-A University Hospital from March 2019 to February 2020. We calculated the overall ratios of the ADR: the ADRs of the group using the older generation HD colonoscopy equipment and the group using the latest HD colonoscopy equipment. Polyp detection rate (PDR), sessile serrated polyp detection rate (SSPDR), and advanced neoplasia detection rate (ANDR) were calculated for each group. Factors related to adenoma detection were identified using logistic regression analysis. RESULTS: Altogether, 2189 patients were included in the study (the older HD colonoscopy group comprising 1183 and the latest HD colonoscopy group comprising 1006). We found that PDR (45.98 vs. 51.69%, p = 0.008) and ADR (35.67 vs. 40.85%, p = 0.013) were significantly higher in the latest generation HD colonoscopy group. The generational differences were not statistically significant for SSPDR (1.94 vs. 2.78%, p = 0.195) or ANDR (4.65 vs. 4.97%, p = 0.726). In the multivariate regression analysis, age, male sex, the latest generation HD colonoscopy, and long withdrawal time were the most significant factors affecting adenoma detection. CONCLUSIONS: The latest generation HD colonoscopy improved PDR and ADR by trainee endoscopists. These findings suggest that latest generation, higher-resolution colonoscopy equipment can improve the quality of colonoscopy for less experienced endoscopists.

Clinical Course of Terminal Ileal Ulcers Observed Incidentally During Colonoscopy.

BACKGROUND: Cecal intubation is essential during colonoscopy, and observation of the terminal ileum is performed in most clinical practices. However, data on terminal ileal (TI) ulcers observed incidentally during colonoscopy are rare. AIM: We aimed to identify the characteristics and clinical course of TI ulcers observed incidentally during colonoscopy. METHODS: Between January 2008 and December 2018, medical records from multi-centers reporting asymptomatic subjects who underwent biopsy on TI ulcers during colonoscopy were retrospectively reviewed. The characteristics of endoscopic findings and clinical course of TI ulcers were analyzed, and the factors affecting the clinical course of TI ulcers were evaluated. RESULTS: The median follow-up durations from first to second colonoscopy and from second to third colonoscopy were 20 months (interquartile range, 12-36) and 24 months (interquartile range, 12-34), respectively. A total of 134 subjects were included in the analysis. The histopathologic findings of TI ulcers were mostly chronic or active ileitis/inflammation (92.7%). On the second colonoscopy, 59 (44.0%) patients had no ulcers, 38 (28.4%) showed a decrease in size or number, and 37 (27.6%) patients showed no change in ulcers. Among 62 subjects who underwent a third colonoscopy, 14 (10.4%) had decreased size or number, 10 (7.5%) had no ulcer change, and two (1.5%) had increased ulcer size or number. In multivariate logistic regression analysis, a star shape was the only factor affecting continuation without improvement of incidental TI ulcers. CONCLUSIONS: Most TI ulcers observed incidentally showed no unusual findings on biopsy and improved on follow-up colonoscopy without treatment.

Non-Invasive Optical Coherence Tomography Data-Based Quantitative Algorithm for the Assessment of Residual Adhesive on Bracket-Removed Dental Surface.

The aim of this study was to quantitatively assess the residual adhesive on orthodontic ceramic bracket-removed dental surface. In orthodontic process, ceramic bracket was repeated debonding physically, then the adhesive remained on the dental surface. The residual adhesive caused a lack of adhesive strength between dental and ceramic bracket. Since commonly used adhesive in orthodontics is translucent, residual adhesive is hard to be detected with conventional microscopes. Therefore, 1310 nm center wavelength swept-source OCT system based on laboratory customized image processing algorithm was used for the precise detection of residual adhesive on tooth surface. The algorithm separates residual adhesive from dental surface by comparing the height of adjacent B-scan images, while providing color-scaled images emphasizing the thickness information of residual adhesive. Finally, the acquired results were compared with microscopic and adhesive remnant index scoring gold standards, while the comparison confirmed the potential merits and the improvements of the proposed method over gold standards.