Layer-by-layer Assembly of Nanosheets with Matching Size and Shape for More Stable Membrane Structure than Nanosheet-Polymer Assembly.

Layer-by-layer (LbL) assembly of oppositely charged materials has been widely used as an approach to make two-dimensional (2D) nanosheet-based membranes, which often involves 2D nanosheets being alternately deposited with polymer-based polyelectrolytes to obtain an electrostabilized nanosheet-polymer structure. In this study, we hypothesized that using 2D nanosheets with matching physical properties as both polyanions and polycations may result in a more ordered nanostructure with better stability than a nanosheet-polymer structure. To compare the differences between nanosheet-nanosheet vs nanosheet-polymer structures, we assembled negatively charged molybdenum disulfide nanosheets (MoS2) with either positively charged graphene oxide (PrGO) nanosheets or positively charged polymer (PDDA). Using combined measurements by ellipsometer and quartz crystal microbalance with dissipation, we discovered that the swelling of MoS2-PrGO in ionic solutions was 60% lower than that of MoS2-PDDA membranes. Meanwhile, the MoS2-PrGO membrane retained its permeability upon drying, whereas the permeability of MoS2-PDDA decreased by 40% due to the restacking of MoS2. Overall, the MoS2-PrGO membrane demonstrated a better filtration performance. Additionally, our X-ray photoelectron spectroscopy results and analysis on layer density revealed a clearer transition in material composition during the LbL synthesis of MoS2-PrGO membranes, and the X-ray diffraction pattern suggested its resemblance to an ordered, layer-stacked structure. In conclusion, the MoS2-PrGO membrane made with nanosheets with matching size, shape, and charge density exhibited a much more aligned stacking structure, resulting in reduced membrane swelling under high salinity solutions, controlled restacking, and improved separation performance.

Non-contrast low-dose CT can be used for volumetry of ADPKD.

BACKGROUND: Kidney volume provides important information for the diagnosis and prognosis of autosomal dominant polycystic kidney disease (ADPKD), as well as for the evaluation of the effects of drugs such as tolvaptan. Non-contrast computed tomography (CT) is commonly used for volumetry, and this study examined the correspondence and correlation of kidney volume measured by standard-dose or low-dose CT. METHODS: Axial standard-dose and low-dose CT images with 1-mm slices were obtained from 24 ADPKD patients. The kidney was segmented in the Synapse 3D software and the kidney volume was calculated using stereology. The kidney volume was compared between the two sets of images using R2, Bland-Altman plots, coefficient of variation, and intra-class correlation coefficients (ICCs). RESULTS: The mean age of the 24 patients was 48.4 ± 10.9 years, and 45.8% were men (n = 11). The mean total kidney volume on standard-dose CT was 1501 ± 838.2 mL. The R2 of volume between standard-dose and low-dose CT was 0.995. In the Bland-Altman plot, except for one case with a large kidney volume, the two measurements were consistent, and the coefficient of variation and ICC were also good (0.02, 0.998). The CT radiation dose (dose-length product) was 229 ± 68 mGy·cm for standard-dose CT and 50 ± 19 mGy·cm for low-dose CT. A comparable volume was obtained with 20% of the radiation dose of standard-dose CT. CONCLUSIONS: Standard-dose and low-dose CT showed comparable kidney volume in ADPKD. Therefore, low-dose CT can substitute for ADPKD volumetry while minimizing radiation exposure.

Clinical Practice Guidelines for Oropharyngeal Dysphagia.

OBJECTIVE: Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one's physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia. METHODS: Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology. RESULTS: Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended. CONCLUSION: This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Theoretical Upper and Lower Limits for Normalized Bandwidth of Digital Phase-Locked Loop in GNSS Receivers.

Determining the loop noise bandwidth and the coherent integration time is essential and important for the design of a reliable digital phase-locked loop (DPLL) in global navigation satellite system (GNSS) receivers. In general, designers set such parameters approximately by utilizing the well-known fact that the DPLL is stable if the normalized bandwidth, which is the product of the integration time and the noise bandwidth, is much less than one. However, actual limit points are not fixed at exactly one, and they vary with the loop filter order and implementation method. Furthermore, a lower limit on the normalized bandwidth may exist. This paper presents theoretical upper and lower limits for the normalized bandwidth of DPLL in GNSS receivers. The upper limit was obtained by examining the stability of DPLL with a special emphasis on the digital integration methods. The stability was investigated in terms of z-plane root loci with and without the consideration of the computational delay, which is a delay induced by the calculation of the discriminator and the loop filter. The lower limit was analyzed using the DPLL measurement error composed of the thermal noise, oscillator phase noise, and dynamic stress error. By utilizing the carrier-to-noise density ratio threshold which indicates the crossing point between the measurement error and the corresponding threshold, the lower limit of the normalized bandwidth is obtained.

Table-Based Adaptive Digital Phase-Locked Loop for GNSS Receivers Operating in Moon Exploration Missions.

An adaptive digital phase-locked loop (DPLL) continually adjusts the noise bandwidth of the loop filter in global navigation satellite system (GNSS) receivers to track signals by measuring the signal-to-noise ratio and/or dynamic stress. Such DPLLs have a relatively large amount of computational complexity compared with the conventional DPLL. A table-based adaptive DPLL is proposed that adjusts the noise bandwidth value by extracting it from the pre-generated table without additional calculations. The values of the noise bandwidth table are computed in an optimal manner in consideration of the thermal noise, oscillator phase noise, and dynamic stress error. The calculation method of the proper integration time to maintain the stability of the loop filter is presented. Additionally, the simulation is configured using the trajectory analysis results from the Moon exploration mission and shows that the proposed algorithm operates stably in harsh environments, while a conventional fixed bandwidth loop cannot. The proposed algorithm has a similar phase jitter performance to the existing adaptive DPLL algorithms and has an execution time that is approximately 2.4-5.4 times faster. It is verified that the proposed algorithm is computationally efficient while maintaining jitter performance.

Ultralong persistent luminescence from carbon dots.

Hour-level persistent luminescence is realized with carbon dots embedded in cyanuric acid, the composition of which is easily obtained by the microwave-assisted heating of carbon dots and urea. By forming donor-acceptor blends, the proposed composition yields intermediate states with long lifetimes, providing a rare-earth-metal-free route to ultralong persistent luminescence.

Low Muscle Mass in Patients Receiving Hemodialysis: Correlations with Vascular Calcification and Vascular Access Failure.

Background: Sarcopenia involves an age-related decline in skeletal muscle mass with functional disability or low muscle strength. Vascular calcification (VC) occurs commonly in patients with chronic kidney disease, in whom it is associated with cardiovascular disease. We aimed to investigate the correlations of low muscle mass with the quantified vascular calcification score (VCS) of the arm of vascular access, as well as whether low muscle mass is associated with the incidence of vascular access failure. Methods: The VCS was measured on non-contrast, arm computed tomography using the Agatston method. The lower muscle mass (LMM) group comprised subjects whose skeletal muscle mass of the lower extremities, as measured using bioelectrical impedance, was lower than the median. Higher VC was defined as a score of 500 or above, corresponding to the highest 40% of VCS. The relationship between LMM and VC was explored using univariate and multivariate logistic regression analyses. Results: Seventy-five patients were included, of whom forty-two (56.0%) were men. The median age was 64 years (interquartile range 58-72 years). Of the 75 patients, 73 satisfied the diagnostic criteria for sarcopenia. The median hemodialysis vintage was 49.4 months (range 32.1-99.2 months). No significant differences were found between the non-LMM and LMM groups in sex, end-stage renal disease etiology, and type of vascular access, although the LMM group showed significantly older age and hemodialysis vintage. LMM presented a significant association with VC (hazard ratio (HR) 3.562; 95% CI, 1.341-9.463; p = 0.011). Upon adjustment for hemodialysis vintage, diabetes, and systolic blood pressure, LMM demonstrated an independent association with VC (HR, 10.415; 95% CI, 2.357-46.024; p = 0.002). The risk of vascular access failure was higher in the LMM group (HR, 3.652; 95%, CI 1.135-11.749; p = 0.03). VC was a full mediator in the relationship of LMM with recurrent vascular access failure. Conclusions: We quantified LMM via bioimpedance analysis and found a heretofore-unreported association between LMM and vascular access failure. LMM increases the risk of VC and has the potential to predict vascular access failure.

Systematic Review of Behavioral Therapy to Improve Swallowing Functions of Patients With Parkinson's Disease.

Decreased swallowing function is a common and main cause of malnutrition and aspiration pneumonia in patients with Parkinson's disease. The aims of this systematic review were to summarize and qualitatively analyze the studies that have been published on behavioral therapies for improving swallowing functions in patients with Parkinson's disease. Studies published from January 2000 to December 2015 were identified via electronic database searches using Ovid-MEDLINE, Ovid-EMBASE, the Cochrane Library, and 8 Korean databases. Two reviewers independently evaluated the studies using inclusion criteria. Nine studies were included, of which 6 evaluated rehabilitation technique studies and 3 evaluated compensatory strategies. The 9 studies were evaluated qualitatively using a methodology checklist of the Scottish Intercollegiate Guideline Network, according to which all of the studies had acceptable quality. The available data on the effects of rehabilitation techniques and compensatory strategies remain insufficient. Further randomized controlled studies should be done to investigate the effect of behavioral therapy on improving swallowing functions in patients with Parkinson's disease.

Dietary vitamin D intake and vitamin D related genetic polymorphisms are not associated with gastric cancer in a hospital-based case-control study in Korea.

There have been few studies on the association between vitamin D levels and gastric cancer in Asian populations, but no studies have been performed on the interactions between vitamin D intake and polymorphisms in the vitamin D pathway. The effects of vitamin D intake, vitamin D related genetic polymorphisms, and their association with the incidence of gastric cancer were investigated in a hospital case-control study, including 715 pairs of newly diagnosed gastric cancer patients and controls matched for age and sex. Correlations between vitamin D intake and plasma vitamin D concentrations were also assessed in a subset of subjects. No statistically significant difference was observed in the dietary intake of vitamin D between the patients and controls, nor were there any evident associations between vitamin D intake and risk of gastric cancer in multivariate analyses. Vitamin D intake significantly correlated with the circulating 25-hydroxyvitamin D levels, but not with the active form of the vitamin, 1,25-dihydroxyvitamin D. There were no statistically significant interactions between vitamin D intake, and VDR or TXNIP polymorphisms. This study suggests that dietary vitamin D intake is not associated with gastric cancer risk, and the genetic polymorphisms of vitamin D-related genes do not modulate the effect of vitamin D with respect to gastric carcinogenesis.

Clinical features of gastric emptying after distal gastrectomy.

PURPOSE: Gastric emptying may influence the quality of life of patients who undergo distal gastrectomy. Little is known, however, about gastric emptying after distal gastrectomy. The aim of our study was to investigate gastric emptying patterns after distal gastrectomy. METHODS: This gastric-emptying study investigated patients who underwent distal gastrectomy in the 6 months or more before May 2008 to July 2013 at Chungbuk National University Hospital with a study sample of 205 patients. We analyzed patterns of gastric emptying. RESULTS: Delayed gastric emptying was found in 109 of the 205 patients (53.2%). Food stasis was more frequent in a group with delayed gastric emptying. In multivariate analysis, risk factors for gastroparesis were laparoscopic operation (hazard ratio [HR], 2.731; P = 0.008) and duration of less than 24 months after distal gastrectomy (HR, 2.795; P = 0.001). Delayed gastric emptying tended to decrease with duration of the postoperative period. CONCLUSION: Delayed gastric emptying is common in distal gastrectomy, and is related to laparoscopic operation and duration of the postoperative period. Food stasis was more frequent in a group with delayed gastric emptying.

The Practice Patterns and Perceptions of Korean Surgeons Regarding Margin Status after Breast-Conserving Surgery.

Two consecutive surveys for breast surgeons in Korea were conducted to comprehend the practice patterns and perceptions on margin status after breast-conserving surgery. The surveys were conducted online in 2014 (initial) and 2016 (follow-up). A total of 126 and 88 responses were obtained in the initial and follow-up survey, respectively. More than 80% of the respondents replied to routinely apply frozen section biopsy for intraoperative margin assessment in both surveys. Re-excision recommendations of the margin for invasive cancer significantly changed from a close margin to a positive margin over time (p=0.033). Most of the respondents (73.8%) defined a negative margin as "no ink on tumor" in invasive cancer, whereas more diverse responses were observed in ductal carcinoma in situ cases. The influence of guideline establishment for negative margins has been identified. A high uptake rate of intraoperative frozen section biopsy was noted and routine use needs reconsideration.

Additive interactions between PRKAA1 polymorphisms and Helicobacter pylori CagA infection associated with gastric cancer risk in Koreans.

Although several studies reported genetic polymorphisms in protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) and their associations with gastric cancer risk, few have evaluated associations between Helicobacter pylori infection and PRKAA1 gene-environment interactions. Here, we evaluated the effects of interactions between H. pylori infection and PRKAA1 polymorphisms on gastric cancer risk in Koreans. In this hospital-based case-control study, PRKAA1 genotypes were analyzed and H. pylori infection and CagA status were examined using a serologic method in 846 pairs of gastric cancer patients and controls matched for age and sex. H. pylori seropositivity was associated with a 1.43-fold [95% confidence interval: 1.12-1.81] increase in the risk of gastric cancer, and CagA low-positive titers during H. pylori infection increased the risk by 1.85-fold (95% confidence interval, 1.38-2.48). Significant positive interaction between the PRKAA1 rs13361707 genotype and H. pylori infection was verified on an additive scale [relative excess risk due to interaction, 0.55; 95% confidence interval, 0.05-1.04; P = 0.030], and the gene-environment interaction between PRKAA1 rs13361707 and CagA status was also statistically significant (relative excess risk due to interaction, 0.50; 95% confidence interval, 0.30-0.70; P < 0.001). Our results indicated that H. pylori infection, CagA status, and PRKAA1 polymorphisms were risk factors for gastric cancer in Koreans, and that the combination of two of these factors rather than their independent effects synergistically increased the risk.

Novalis Stereotactic Radiosurgery for Spinal Dural Arteriovenous Fistula.

The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system.

The role of the addition of ovarian suppression to tamoxifen in young women with hormone-sensitive breast cancer who remain premenopausal or regain menstruation after chemotherapy (ASTRRA): study protocol for a randomized controlled trial and progress.

BACKGROUND: Ovarian function suppression (OFS) has been shown to be effective as adjuvant endocrine therapy in premenopausal women with hormone receptor-positive breast cancer. However, it is currently unclear if addition of OFS to standard tamoxifen therapy after completion of adjuvant chemotherapy results in a survival benefit. In 2008, the Korean Breast Cancer Society Study Group initiated the ASTRRA randomized phase III trial to evaluate the efficacy of OFS in addition to standard tamoxifen treatment in hormone receptor-positive breast cancer patients who remain or regain premenopausal status after chemotherapy. METHODS: Premenopausal women with estrogen receptor-positive breast cancer treated with definitive surgery were enrolled after completion of neoadjuvant or adjuvant chemotherapy. Ovarian function was assessed at the time of enrollment and every 6 months for 2 years by follicular-stimulating hormone levels and bleeding history. If ovarian function was confirmed as premenopausal status, the patient was randomized to receive 2 years of goserelin plus 5 years of tamoxifen treatment or 5 years of tamoxifen alone. The primary end point will be the comparison of the 5-year disease-free survival rates between the OFS and tamoxifen alone groups. Patient recruitment was finished on March 2014 with the inclusion of a total of 1483 patients. The interim analysis will be performed at the time of the observation of the 187th event. DISCUSSION: This study will provide evidence of the benefit of OFS plus tamoxifen compared with tamoxifen only in premenopausal patients with estrogen receptor-positive breast cancer treated with chemotherapy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00912548 . Registered May 31 2009. Korean Breast Cancer Society Study Group Register KBCSG005 . Registered October 26 2009.

Pleomorphic Adenoma with Sarcomatous Change in a Lacrimal Gland.

A 69-year-old man was referred with left exophthalmos. Computed tomographic (CT) findings detected a well-circumscribed mass in the left side of the intraorbital cavity. At that time, he refused the further evaluation and treatment. About three years later, the size of the mass had enlarged, and the patient's symptoms were getting worse. The mass was completely removed with frontotemporal craniotomy and superolateral orbitotomy. In operative findings, the mass had originated in the lacrimal gland and was well-encapsulated without invasion to the surrounding tissue. In the pathologic findings, the tumor consisted of pleomorphic adenoma with osteosarcomatous change of stromal components. Postoperatively, the adjuvant radiotherapy was done four weeks later. The patient's symptoms were improved. The pleomorphic adenoma with osteosarcomatous change is extremely rare and appropriate treatment is not clearly established. We would like to report this rare case with a review of the literature.

Insulin-like growth factor 1 receptor expression in breast cancer tissue and mammographic density.

The aim of this study was to evaluate the association between insulin-like growth factor 1 receptor (IGF-1R) expression in breast cancer tissue and mammographic density and the clinical significance of IGF-1R overexpression. A total of 167 patients with primary invasive breast cancer were analyzed. Mammographic breast density and IGF-1R overexpression were correlated with clinicopathological parameters and analyzed by overall survival (OS) and disease-free survival (DFS). Increased breast tissue density was significantly associated with age, body mass index, menopausal status, histological grade and IGF-1R overexpression in the univariate analysis and with age (P=0.001), histological grade (P=0.045) and IGF-1R overexpression (P=0.021) in the multivariate analysis. IGF-1R overexpression was significantly associated with dense breast tissue in patients aged >40 years (P=0.002). IGF-1R overexpression in breast cancer in premenopausal women was associated with human epidermal growth factor receptor 2 (HER-2) positivity (P=0.016) and worse DFS (P=0.0414). There was no significant difference in OS and DFS between dense and non-dense breast tissue. IGF-1R expression in breast cancer tissue was significantly associated with mammographic breast tissue density in patients aged >40 years. It appears that IGF-1R expression in breast cancer tissue plays an important role in breast cancer in patients with dense breast tissue. In premenopausal women, IGF-1R overexpression in breast cancer tissue was significantly associated with HER-2 positivity and poor DFS.

New surgical approach for limbal dermoids in children: simple excision, corneal tattooing, and sutureless limboconjunctival autograft.

PURPOSE: To evaluate the efficacy of combined surgery of simple excision, corneal tattooing, and a sutureless limboconjunctival autograft in pediatric patients with grade 1 limbal dermoids. METHODS: We treated 4 eyes of 4 patients with combined surgery of corneal tattooing and a sutureless limboconjunctival autograft with simple excision of limbal dermoids. Preoperative and postoperative visual acuity, postoperative recovery time, cosmetic improvements, patient compliance, and complication rates were reviewed. RESULTS: The mean follow-up period in this study was 27.3 ± 2.8 (range, 24-30) months. Visual acuity was stable during the follow-up period. Resolution of patient discomfort and wound epithelialization was achieved in 1 week. Cosmetic outcomes improved in view of corneal opacity and conjunctival vascularization. All patients were satisfied with the cosmetic results with no complications. CONCLUSIONS: Corneal tattooing and a sutureless limboconjunctival autograft after simple excision of limbal dermoids can lead to a satisfactory cosmetic outcome, better compliance, and early postoperative recovery without complications for grade 1 limbal dermoids in pediatric patients.

CEACAM6 as detected by the AP11 antibody is a marker notable for mucin-producing adenocarcinomas.

A new monoclonal antibody recognizing CEACAM6, which we named AP11, was generated by immunizing BALB/c mice with phytohemagglutinin-activated human peripheral blood mononuclear cells. This study aims to evaluate whether CEACAM6 can serve as a tumor marker using AP11. We examined the expression of CEACAM6 with AP11 in 11 human carcinoma cell lines by flow cytometry and 439 human tissues including 282 tumor tissues and 157 normal tissues by immunohistochemistry. CEACAM6 epitope recognized by AP11 was well preserved in formalin-fixed and paraffin-embedded tissues. Adenocarcinomas of the stomach (86%), colorectum (95%), pancreas (100%), and lung (83%), urinary bladder (100%), and mucinous ovarian tumors (88%) had a high rate of CEACAM6 immunoreactivity. We observed a variable expression of CEACAM6 in hepatocellular carcinomas (35%), squamous cell carcinomas of the lung (60%), renal cell carcinomas (14%), urothelial carcinomas (13%), serous carcinomas of the ovary (17%), and breast carcinomas (11%). Small-cell carcinomas of the lung, prostatic adenocarcinomas, papillary thyroid carcinomas, malignant melanomas, giant cell tumors, and osteosarcomas were negative for CEACAM6. All normal tissues of various organs were negative for CEACAM6. In conclusion, CEACAM6 as detected by AP11, may serve as a marker for mucin-producing adenocarcinomas of the gastrointestinal tract and ovary as well as non-small cell lung cancer. Thus, AP11 represents a valuable diagnostic tool for detecting CEACMA6-positive cancers.

H2 Receptor-Mediated Relaxation of Circular Smooth Muscle in Human Gastric Corpus: the Role of Nitric Oxide (NO).

This study was designed to examine the effects of histamine on gastric motility and its specific receptor in the circular smooth muscle of the human gastric corpus. Histamine mainly produced tonic relaxation in a concentration-dependent and reversible manner, although histamine enhanced contractility in a minor portion of tissues tested. Histamine-induced tonic relaxation was nerve-insensitive because pretreatment with nerve blockers cocktail (NBC) did not inhibit relaxation. Additionally, K(+) channel blockers, such as tetraethylammonium (TEA), apamin (APA), and glibenclamide (Glib), had no effect. However, N(G)-nitro-L-arginine methyl ester (L-NAME) and 1H-(1,2,4)oxadiazolo (4,3-A) quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC), did inhibit histamine-induced tonic relaxation. In particular, histamine-induced tonic relaxation was converted to tonic contraction by pretreatment with L-NAME. Ranitidine, the H2 receptor blocker, inhibited histamine-induced tonic relaxation. These findings suggest that histamine produced relaxation in circular smooth muscle of human gastric smooth muscle through H2 receptor and NO/sGC pathways.

Neurocutaneous melanosis in association with dandy-walker complex with extensive intracerebral and spinal cord involvement.

Neurocutaneous melanosis (NCM) is a rare congenital syndrome consisting of benign or malignant melanotic tumors of the central nervous system with large or numerous cutaneous melanocytic nevi. The Dandy-Walker complex (DWC) is characterized by an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. These each two conditions are rare, but NCM associated with DWC is even more rare. Most patients of NCM with DWC present neurological symptoms early in life such as intracranial hemorrhage, hydrocephalus, and malignant transformation of the melanocytes. We report a 14-year-old male patient who was finally diagnosed as NCM in association with DWC with extensive intracerebral and spinal cord involvement.