Social Network and Knowledge Accessibility of Project Teams: A Multi-level Approach

This study deals with the relationship between the project team\u27s social network and knowledge accessibility from an empirical aspect. What kind of network structure is desirable to improve project team members\u27 knowledge accessibility? Does a strong connection among group members improve their knowledge accessibility? Otherwise, does the expansion of the external network of a group improve its members\u27 knowledge accessibility more efficiently? This study aims to contribute to developing existing network theories and knowledge management theories by answering these questions. To solve the raised research questions, a multi-level research model was developed on the basis of social network theory. From a social network analysis which was conducted on 172 consultants and 42 project teams in 5 global consulting companies doing business in Korea, it was found that the research results backed the existing two different social network mechanisms: closure mechanism and brokerage mechanism. However, the effect of social network on knowledge accessibility of project team members varied along the type of network involved. This study is meaningful in that it overcame the limits of the unit of analysis shown in existing studies by distinguishing group-level network density from individual-level network properties, and by analyzing the moderating effect between them

Different Amyloid-β Self-Assemblies Have Distinct Effects on Intracellular Tau Aggregation.

Alzheimer's disease (AD) pathology is characterized by the aggregation of beta-amyloid (Aβ) and tau in the form of amyloid plaques and neurofibrillary tangles in the brain. It has been found that a synergistic relationship between these two proteins may contribute to their roles in disease progression. However, how Aβ and tau interact has not been fully characterized. Here, we analyze how tau seeding or aggregation is influenced by different Aβ self-assemblies (fibrils and oligomers). Our cellular assays utilizing tau biosensor cells show that transduction of Aβ oligomers into the cells greatly enhances seeded tau aggregation in a concentration-dependent manner. In contrast, transduced Aβ fibrils slightly reduce tau seeding while untransduced Aβ fibrils promote it. We also observe that the transduction of α-synuclein fibrils, another amyloid protein, has no effect on tau seeding. The enhancement of tau seeding by Aβ oligomers was confirmed using tau fibril seeds derived from both recombinant tau and PS19 mouse brain extracts containing human tau. Our findings highlight the importance of considering the specific form and cellular location of Aβ self-assembly when studying the relationship between Aβ and tau in future AD therapeutic development

Cryo-EM of full-length α-synuclein reveals fibril polymorphs with a common structural kernel.

α-Synuclein (aSyn) fibrillar polymorphs have distinct in vitro and in vivo seeding activities, contributing differently to synucleinopathies. Despite numerous prior attempts, how polymorphic aSyn fibrils differ in atomic structure remains elusive. Here, we present fibril polymorphs from the full-length recombinant human aSyn and their seeding capacity and cytotoxicity in vitro. By cryo-electron microscopy helical reconstruction, we determine the structures of the two predominant species, a rod and a twister, both at 3.7 Å resolution. Our atomic models reveal that both polymorphs share a kernel structure of a bent β-arch, but differ in their inter-protofilament interfaces. Thus, different packing of the same kernel structure gives rise to distinct fibril polymorphs. Analyses of disease-related familial mutations suggest their potential contribution to the pathogenesis of synucleinopathies by altering population distribution of the fibril polymorphs. Drug design targeting amyloid fibrils in neurodegenerative diseases should consider the formation and distribution of concurrent fibril polymorphs

Ischemic axonal injury up-regulates MARK4 in cortical neurons and primes tau phosphorylation and aggregation.

Ischemic injury to white matter tracts is increasingly recognized to play a key role in age-related cognitive decline, vascular dementia, and Alzheimer's disease. Knowledge of the effects of ischemic axonal injury on cortical neurons is limited yet critical to identifying molecular pathways that link neurodegeneration and ischemia. Using a mouse model of subcortical white matter ischemic injury coupled with retrograde neuronal tracing, we employed magnetic affinity cell sorting with fluorescence-activated cell sorting to capture layer-specific cortical neurons and performed RNA-sequencing. With this approach, we identified a role for microtubule reorganization within stroke-injured neurons acting through the regulation of tau. We find that subcortical stroke-injured Layer 5 cortical neurons up-regulate the microtubule affinity-regulating kinase, Mark4, in response to axonal injury. Stroke-induced up-regulation of Mark4 is associated with selective remodeling of the apical dendrite after stroke and the phosphorylation of tau in vivo. In a cell-based tau biosensor assay, Mark4 promotes the aggregation of human tau in vitro. Increased expression of Mark4 after ischemic axonal injury in deep layer cortical neurons provides new evidence for synergism between axonal and neurodegenerative pathologies by priming of tau phosphorylation and aggregation

Endoscopic Thyroidectomy via an Axillo-Breast Approach without Gas Insufflation for Benign Thyroid Nodules and Micropapillary Carcinomas: Preliminary Results

PURPOSE: To examine the feasibility of endoscopic thyroidectomy (ET) via an axillo- breast approach without gas insufflation for large thyroid tumors and micropapillary carcinomas. MATERIALS AND METHODS: The patients in the benign group were separated into groups 1 (n=95, <4 cm in tumor diameter) and 2 (n=37, ≥4 cm in tumor diameter). Also, 57 patients in the micropapillary carcinoma group underwent an endoscopic hemithyroidectomy (HT) (group 3) and were compared with 60 patients who received conventional open HT (group 4). Postoperative functional outcome, local complications, surgical outcomes, and pathological outcomes were compared between the groups. RESULTS: In the benign group, there was no significant difference in mean operating time, hospital stay, or overall perioperative complications between the two groups. In the micropapillary carcinoma group, mean operating time and hospital stay in group 3 were significantly longer than in group 4 (p=0.015 and p≤0.001). The overall perioperative complications did not differ significantly between the groups. The postoperative cosmetic result was better in groups 1-3 (endo group) than in group 4 (open group). CONCLUSION: ET via a gasless axillo-breast approach seems to be a safe procedure even for benign thyroid lesions ≥4 cm and micropapillary carcinomas. Although it has the advantage of better cosmetic results over open thyroidectomy, there is room for improvement in terms of lessening its invasiveness and shortening the operative time.ope

CASS (CyanoAcrylate closure versus Surgical Stripping for incompetent saphenous veins) study: a randomized controlled trial comparing clinical outcomes after cyanoacrylate closure and surgical stripping for the treatment of incompetent saphenous veins

Background Several modalities are used for the treatment of varicose veins. Open surgical treatment with ligation and stripping of the saphenous vein has been the standard of care for many years. Endovenous thermal ablation has been shown to be a safe and effective alternative with high, long-term, target-vein closure rates. Despite this, there is the possibility of thermal injury to surrounding structures. The recently introduced cyanoacrylate closure is also considered to be a good alternative and the risk of injury to surrounding structures is minimal. The purpose of this study is to demonstrate the non-inferiority of cyanoacrylate closure with the VenaSeal™ closure system compared to surgical stripping in terms of clinical outcomes for the treatment of incompetent great saphenous veins. Methods/design This is an open-label, multicenter, prospective, randomized controlled trial evaluating the non-inferior clinical outcomes of cyanoacrylate closure compared to surgical stripping for the treatment of incompetent saphenous veins. After baseline measurements, participants will be randomly allocated into either the cyanoacrylate closure group or the surgical-stripping group. The primary endpoint of the study is the complete closure rate of the target vein in the cyanoacrylate closure group, and the absence of venous reflux or residual venous tissue after surgical stripping in the surgical-stripping group. These endpoints will be measured by Doppler ultrasound performed by qualified vascular technologists or investigators at 3 months after treatment. Secondary outcomes include perioperative pain, postoperative ecchymosis, clinical assessment (including general and disease-specific quality of life evaluations), complete closure rate, and absence of venous reflux or residual venous tissue at the 12- and 24-month follow-ups, as well as all adverse event rates during the 24-month follow-up period. Discussion This multicenter randomized controlled trial is designed to show non-inferiority in terms of complete closure rate of cyanoacrylate compared to surgical stripping for the treatment of incompetent saphenous veins. Trial registration Clinical Research Information Service (CRIS), ID: KCT0003203. Registered on 20 September 2018.This is an investigator-sponsored study supported by a grant from Medtronic Korea Co., Ltd

The Jeju Weasel, Mustela sibilica quelpartis, A New Definitive Host for Gnathostoma nipponicum Yamaguti, 1941

Adult gnathostomes were discovered in the stomach of the Jeju weasel, Mustela sibilica quelpartis, road-killed in Jeju-do (Province). Their morphological characters were examined to identify the species. Total 50 gnathostome adults were collected from 6 out of 10 weasels examined. In infected weasels, 4-6 worms were grouped and embedded in each granulomatous gastric tumor, except 1 weasel. Male worms were 25.0×1.4 mm in average size, and had a tail with pedunculate papillae, a spicule, and minute tegumental spines. Females were 40.0×2.5 mm in average size, and had a tail without tegumental spines. Pointed and posteriorly curved hooklets were arranged in 8-10 rows on the head bulb. Tegumental spines were distributed from behind the head bulb to the middle portion of the body. The spines were different in size and shape by the distribution level of the body surface. Fertilized eggs were 65.5×38.9 µm in average size, and had a mucoid plug at 1 pole. These gnathostomes from Jeju weasels were identified as Gnathostoma nipponicum Yamaguti, 1941. By the present study, it was confirmed for the first time that G. nipponicum is distributed in Jeju-do, the Republic of Korea, and the Jeju weasel, M. sibilica quelpartis, plays a crucial role for its definitive host

Anesthetic management of an adult patient with Rett syndrome and limited mouth opening -A case report-

Rett syndrome is a neurological disease that occurs only in females and it manifests with mental retardation, seizures, movement disorders, autistic behavior and abnormal breathing. A 19-year-old female with Rett syndrome underwent ophthalmologic surgery under general anesthesia at our institution. Airway control was difficult due to her limited mouth opening. We recommend that anesthesiologists should have proper knowledge about this disease and the patients to avoid the complications and problems that can be encountered during the perioperative period

Prognostic Factors Influencing Infection-related Mortality in Patients with Acute Leukemia in Korea

We retrospectively reviewed the medical records of 284 patients with neutropenic fever following chemotherapy for acute leukemia at the Catholic Hematopoietic Stem Cell Transplantation Center from January 1998 to December 1999, to identify prognostic factors for infection related mortality. Twenty-eight patients died of infections. There was no difference in median age, gender ratio, or underlying disease between the dying and surviving groups. Bacteria were the main pathogens following chemotherapy, and Gram positive organisms predominated in the dying group. Pneumonia and sepsis were the main causes of death. There were 72 cases of invasive fungal infection and their mortality was 27.8%. Invasive fungal infection and previous history of fungal infection were independent prognostic factors for outcome. Recovery from neutropenia was the significant protective factor for mortality. In conclusion, the prognostic factors identified in this study could be useful for deciding on more intensive treatment for those patients at greater risk of death. To our knowledge, this is the first Korean study delineating prognostic factors in acute leukemic patients with infectious complications

Additional Effects of Back-Shu Electroacupuncture and Moxibustion in Cardioprotection of Rat Ischemia-Reperfusion Injury

Many preclinical studies show that electroacupuncture (EA) on PC6 and ST36 can reduce infarct size after ischemia-reperfusion (IR) injury. Yet studies to enhance the treatment effect size are limited. The purpose of this study was to explore whether EA has additional myocardial protective effects on an ischemia-reperfusion (IR) injury rat model when back-shu EA and moxibustion are added. SD rats were divided into several groups and treated with either EA only, EA + back-shu EA (B), or EA + B + moxibustion (M) for 5 consecutive days. Transthoracic echocardiography and molecular and immunohistochemical evaluations were performed. It was found that although myocardial infarct areas were significantly lower and cardiac function was also significantly preserved in the three treatment groups compared to the placebo group, there were no additional differences between the three treatment groups. In addition, HSP20 and HSP27 were expressed significantly more in the treatment groups. The results suggest that adding several treatments does not necessarily increase protection. Our study corroborates previous findings that more treatment, such as prolonging EA duration or increasing EA intensity, does not always lead to better results. Other methods of increasing treatment effect size should be explored