Characterization of single photon sources for radiometry applications at room temperature

A single photon source with high repeatability and low uncertainties is the key element for few-photon metrology based on photon numbers. While low photon number fluctuations and high repeatability are important figures for qualification as a standard light source, these characteristics are limited in single photon emitters by some malicious phenomena like blinking or internal relaxations to varying degrees in different materials. This study seeks to characterize photon number fluctuations and repeatability for radiometry applications at room temperature. For generality in this study, we collected photon statistics data with various single photon emitters of $g^{(2)}(0) < 1$ at low excitation power and room temperature in three material platforms: silicon vacancy in diamond, defects in GaN, and vacancy in hBN. We found common factors related with the relaxation times of the internal states that indirectly affect photon number stability. We observed a high stability of photon number with defects in GaN due to faster relaxations compared with vacancies in hBN, which on the other hand produced high rates ($> 10^6$) of photons per second. Finally, we demonstrate repeatable radiant flux measurements of a bright hBN single photon emitter for a wide radiant flux range from a few tens of femtowatts to one picowatt.Comment: Submitted to: Materials for Quantum Technology (IOP

Visceral Myopathy of Intestinal Pseudoobstruction

Intestinal pseudoobstruction is a syndrome complex caused by a variety of disorders of various etiology. It can be classified pathologically as visceral myopathy and visceral neuropathy. The sporadic form of visceral myopathy is characterized histologically by vacuolar degeneration and fibrosis of smooth muscle but differs from the familial form only by the absence of other affected family members. We studied 6 cases with intestinal pseudoobstruction classified as sporadic visceral myopathy. They were four boys and two girls, and were two neonates, two infants and two children. The duration of symptoms ranged from two days to two years. Two babies were dead from pneumonia and sepsis. Others were alleviated after surgical resection of the bowel. Both small and large intestines were found affected in autopsy cases. Histopathologic features were vacuolar degeneration of muscularis propria, disproportionate hypoplasia of outer muscle layer, abnormal muscle direction of muscularis propria, submucosal and/or interstitial fibrosis and extra muscle layering. It is presumed that a variety of histopathologic features accounts for visceral myopathy of intestinal pseudoobstruction

Risk Factors for an Iatrogenic Mallory-Weiss Tear Requiring Bleeding Control during a Screening Upper Endoscopy

Background and Aim. In some cases of iatrogenic Mallory-Weiss tears (MWTs), hemostasis is needed due to severe mucosal tearing with bleeding. Therefore, we aimed to evaluate the risk factors for severe iatrogenic MWTs and the methods of endoscopic bleeding control. Materials and Methods. Between January 2008 and December 2012, 426,085 cases of screening upper endoscopy were performed at the Asan Medical Center. We retrospectively analyzed the risk factors for severe iatrogenic MWTs requiring an endoscopic procedure and the treatment modalities of bleeding control. Results. Iatrogenic MWTs occurred in 546 cases (0.13%) of screening upper endoscopy in 539 patients. Bleeding control due to severe bleeding was applied in 71 cases (13.0%), and rebleeding after initial bleeding control occurred in 1 case. Multivariate analysis showed that old age, a history of distal gastrectomy, and a less-experienced endoscopist (fewer than 2,237.5 endoscopic procedures at the time of the MWT) were associated with severe iatrogenic MWTs requiring an endoscopic procedure. Among 71 cases requiring bleeding control, a hemoclip was used in 81.7% (58 cases). Conclusions. Screening endoscopy procedures should be carefully performed when patients are in their old age and have a history of distal gastrectomy, particularly if the endoscopist is less experienced

Is Ex Vivo Training before In Vivo Training Effective in Learning Gastric Endoscopic Submucosal Dissection?

Background/Aims The learning curve is essential in endoscopic submucosal dissection (ESD) training to improve outcomes and reduce the risk of procedure-related complications. We compared the outcomes of gastric ESD in live pigs performed by inexperienced endoscopists with or without ex vivo training. Materials and Methods At the Olympus Medical Training and Education Center, nine endoscopists inexperienced in ESD were randomly divided into two groups (group A: ex vivo training followed by in vivo training; group B: in vivo training only), and they performed gastric ESDs. Results A total of 18 ESDs were performed. The en bloc resection rate was 88.9% (16/18), and the complete resection rate was 94.4% (17/18). The median specimen size was 2.5 cm in group A and 2.1 cm in group B (P=0.227). There was no significant difference in the procedure time between the two groups, except for the marking time (0′58″ vs. 2′58″, P=0.027). However, group A took a shorter time in dissecting the same area than group B (109 vs. 246 sec/cm2, P=0.083). Complication rates were not significantly different between both groups. Conclusions The procedure time during in vivo ESD training in pigs may be shortened by prior ex vivo training. However, the ex vivo model presented poor air inflation, unstable fixation, and excessive mucosal hardness for cutting. An advanced simulator or sufficient ex vivo training may be effective in training for the ESD procedure

Outcomes of endoscopic submucosal dissection for superficial esophageal neoplasms in patients with liver cirrhosis

Background/Aims The treatment of superficial esophageal neoplasms (SENs) in cirrhotic patients is challenging and rarely investigated. We evaluated the outcomes of endoscopic submucosal dissection (ESD) to determine the efficacy and safety of treating SENs in patients with liver cirrhosis. Methods The baseline characteristics and treatment outcomes of patients who underwent ESD for SENs between November 2005 and December 2017 were retrospectively reviewed. Results ESD was performed in 437 patients with 481 SENs, including 15 cirrhotic patients with 17 SENs. En bloc resection (88.2% vs. 97.0%) and curative resection (64.7% vs. 78.9%) rates were not different between the cirrhosis and non-cirrhosis groups (p=0.105 and p=0.224, respectively). Bleeding was more common in cirrhotic patients (p=0.054), and all cases were successfully controlled endoscopically. The median procedure and hospitalization duration did not differ between the groups. Overall survival was lower in cirrhotic patients (p=0.003), while disease-specific survival did not differ between the groups (p=0.85). Conclusions ESD could be a safe and effective treatment option for SENs in patients with cirrhosis. Detailed preprocedural assessments are needed, including determination of liver function, esophageal varix status, and remaining life expectancy, to identify patients who will obtain the greatest benefit

Identification of Novel Reference Genes Using Multiplatform Expression Data and Their Validation for Quantitative Gene Expression Analysis

Normalization of mRNA levels using endogenous reference genes (ERGs) is critical for an accurate comparison of gene expression between different samples. Despite the popularity of traditional ERGs (tERGs) such as GAPDH and ACTB, their expression variability in different tissues or disease status has been reported. Here, we first selected candidate housekeeping genes (HKGs) using human gene expression data from different platforms including EST, SAGE, and microarray, and 13 novel ERGs (nERGs) (ARL8B, CTBP1, CUL1, DIMT1L, FBXW2, GPBP1, LUC7L2, OAZ1, PAPOLA, SPG21, TRIM27, UBQLN1, ZNF207) were further identified from these HKGs. The mean coefficient variation (CV) values of nERGs were significantly lower than those of tERGs and the expression level of most nERGs was relatively lower than high expressing tERGs in all dataset. The higher expression stability and lower expression levels of most nERGs were validated in 108 human samples including formalin-fixed paraffin-embedded (FFPE) tissues, frozen tissues and cell lines, through quantitative real-time RT-PCR (qRT-PCR). Furthermore, the optimal number of nERGs required for accurate normalization was as few as two, while four genes were required when using tERGs in FFPE tissues. Most nERGs identified in this study should be better reference genes than tERGs, based on their higher expression stability and fewer numbers needed for normalization when multiple ERGs are required

Endoscopic Submucosal Dissection for Treatment of Localized Gastric Mucosa-associated Lymphoid Tissue Lymphoma: A Case Series

Background/Aims The treatment for gastric mucosa-associated lymphoid tissue lymphoma (MALToma) generally involves eradication of Helicobacter pylori. However, MALToma lesions may recur even without H. pylori re-infection. Furthermore, the remission rate of H. pylori-negative MALToma after eradication is low. Therefore, herein, we report on endoscopic submucosal dissection (ESD) as a treatment strategy for gastric MALToma. Methods We retrospectively reviewed the data of all patients of gastric MALToma who underwent endoscopic resection at our institution between January 2000 and December 2021. Clinical remission was defined as complete histological remission or probable minimal residual disease according to the GELA grading system for post-treatment evaluation of gastric MALToma. Results Six patients with gastric MALToma underwent ESD. Two patients were diagnosed with gastric MALToma, which improved after eradication treatment and relapsed approximately 36 and 41 months later, respectively. These patients had singular lesions localized to the mucosa and did not experience H. pylori re-infection. The lesions were successfully removed via ESD. The remaining four patients had H. pylori-negative gastric MALToma. These patients also had single, localized lesions that were removed via ESD. All the patients remained in clinical remission until the final follow-up. Conclusions ESD is a safe and effective intervention for H. pylori-negative gastric MALToma when the lesion is single and confined to the mucosal layer