11 research outputs found
Optimal timing of endoscopic retrograde cholangiopancreatography for acute cholangitis associated with distal malignant biliary obstruction
Background
There is a lack of studies regarding the optimal timing for endoscopic retrograde cholangiopancreatography (ERCP) in patients with cholangitis caused by distal malignant biliary obstruction (MBO). This study aims to investigate the optimal timing of ERCP in patients with acute cholangitis associated with distal MBO with a naïve papilla.
Methods
A total of 421 patients with acute cholangitis, associated with distal MBO, were enrolled for this study. An urgent ERCP was defined as being an ERCP performed within 24 h following emergency room (ER) arrival, and early ERCP was defined as an ERCP performed between 24 and 48 h following ER arrival. We evaluated both 30-day and 180-day mortality as primary outcomes, according to the timing of the ERCP.
Results
The urgent ERCP group showed the lowest 30-day mortality rate (2.2%), as compared to the early and delayed ERCP groups (4.3% and 13.5%) (P < 0.001). The 180-day mortality rate was lowest in the urgent ERCP group, followed by early ERCP and delayed ERCP groups (39.4%, 44.8%, 60.8%; P = 0.006). A subgroup analysis showed that in both the primary distal MBO group, as well as in the moderate-to-severe cholangitis group, the urgent ERCP had significantly improved in both 30-day and 180-day mortality rates. However, in the secondary MBO and mild cholangitis groups, the difference in mortality rate between urgent, early, and delayed ERCP groups was not significant.
Conclusions
In patients with acute cholangitis associated with distal MBO, urgent ERCP might be helpful in improving the prognosis, especially in patients with primary distal MBO or moderate-to-severe cholangitis
High‐Yield‐Stress Particle‐Stabilized Emulsion for Form‐Factor‐Free Thermal Pastes with High Thermal Conductivity, Stability, and Recyclability
Abstract Thermal pastes, thermally conductive fillers dispersed in liquid matrices, are widely used as thermal interface materials (TIMs). TIMs transfer heat generated from electronics to the surroundings, ensuring optimal operating temperatures. Thus, it is crucial to obtain high thermal conductivity (TC) by forming a continuous heat‐conduction pathway through interconnected filler‐networks within the TIM. Therefore, for paste‐type TIMs with spherical fillers, high TC can only be realized at sufficiently high filler loadings (>60 vol%). However, the pastes bearing such high filler loadings are thick, stiff, and less applicable. To these ends, particle‐stabilized emulsions composed of immiscible liquids (silicone oil and glycerol) and spherical alumina are utilized as thermal pastes. Owing to this structure, the resulting form‐factor‐free thermal paste exhibits higher TC and stability than a simple mixture consisting of alumina and a single‐liquid‐matrix (either silicone oil or glycerol). Furthermore, the high applicability of the emulsion‐type pastes enables syringe extrusion, 3D printing, multiple cycles of reprocessing/molding, and eco‐friendly recycling
Activation of the Transducers of Unfolded Protein Response in Plants
Maintenance of homeostasis of the endoplasmic reticulum (ER) ensures the balance between loading of nascent proteins and their secretion. Certain developmental conditions or environmental stressors affect protein folding causing ER stress. The resultant ER stress is mitigated by upregulating a set of stress-responsive genes in the nucleus modulating the mechanism of the unfolded protein response (UPR). In plants, the UPR is mediated by two major pathways; by the proteolytic processing of bZIP17/28 and by the IRE1-mediated splicing of bZIP60 mRNA. Recent studies have shown the involvement of plant-specific NAC transcription factors in UPR regulation. The molecular mechanisms activating plant-UPR transducers are only recently being unveiled. This review focuses on important structural features involved in the activation of the UPR transducers like bZIP17/28/60, IRE1, BAG7, and NAC017/062/089/103. Also, we discuss the activation of the UPR pathways, including BAG7-bZIP28 and IRE1-bZIP60, in detail, together with the NAC-TFs, which adds a new paradigm to the plant UPR
Effect of Measurement System Configuration and Operating Conditions on 2D Material-Based Gas Sensor Sensitivity
Gas sensors applied in real-time detection of toxic gas leakage, air pollution, and respiration patterns require a reliable test platform to evaluate their characteristics, such as sensitivity and detection limits. However, securing reliable characteristics of a gas sensor is difficult, owing to the structural difference between the gas sensor measurement platform and the difference in measurement methods. This study investigates the effect of measurement conditions and system configurations on the sensitivity of two-dimensional (2D) material-based gas sensors. Herein, we developed a testbed to evaluate the response characteristics of MoS2-based gas sensors under a NO2 gas flow, which allows variations in their system configurations. Additionally, we demonstrated that the distance between the gas inlet and the sensor and gas inlet orientation influences the sensor performance. As the distance to the 2D gas sensor surface decreased from 4 to 2 mm, the sensitivity of the sensor improved to 9.20%. Furthermore, when the gas inlet orientation was perpendicular to the gas sensor surface, the sensitivity of the sensor was the maximum (4.29%). To attain the optimum operating conditions of the MoS2-based gas sensor, the effects of measurement conditions, such as gas concentration and temperature, on the sensitivity of the gas sensor were investigated
Backbone assignment of the OmpA-like domain of peptidoglycan-associated lipoprotein from Acinetobacter baumannii
Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen which induces the cytotoxicity of host cells by nosocomial infections. Peptidoglycan-associated lipoprotein (Pal) is one component of Tol-Pal system, which is involved in maintaining the integrity and stability of the outer membrane (OM) as well as the virulence of bacterial pathogens. Pal is composed of N-terminal hydrophobic domain anchoring to the OM and C-terminal OmpA-like domain interacting with peptidoglycan. Herein, we report the preparation of protein sample and the backbone assignment of recombinant OmpA-like domain of Pal protein from Acinetobacter baumannii (AbPal-71). All the backbone chemical shifts of AbPal-71 (Cα, Cβ, CO, HN, and N) were completely assigned and the secondary structure was estimated from the assigned chemical shifts. This result shows that AbPal-71 is a typical OmpA-like fold, which consists of three α-helices and four β-strands. Based on this NMR spectroscopic results, the three dimensional structural study and the interaction study between AbPal-71 and peptidoglycan are in progress
RNA Chaperone Function of a Universal Stress Protein in Arabidopsis Confers Enhanced Cold Stress Tolerance in Plants
The physiological function of Arabidopsis thaliana universal stress protein (AtUSP) in plant has remained unclear. Thus, we report here the functional role of the Arabidopsis universal stress protein, AtUSP (At3g53990). To determine how AtUSP affects physiological responses towards cold stress, AtUSP overexpression (AtUSP OE) and T-DNA insertion knock-out (atusp, SALK_146059) mutant lines were used. The results indicated that AtUSP OE enhanced plant tolerance to cold stress, whereas atusp did not. AtUSP is localized in the nucleus and cytoplasm, and cold stress significantly affects RNA metabolism such as by misfolding and secondary structure changes of RNA. Therefore, we investigated the relationship of AtUSP with RNA metabolism. We found that AtUSP can bind nucleic acids, including single- and double-stranded DNA and luciferase mRNA. AtUSP also displayed strong nucleic acid-melting activity. We expressed AtUSP in RL211 Escherichia coli, which contains a hairpin-loop RNA structure upstream of chloramphenicol acetyltransferase (CAT), and observed that AtUSP exhibited anti-termination activity that enabled CAT gene expression. AtUSP expression in the cold-sensitive Escherichia coli (E. coli) mutant BX04 complemented the cold sensitivity of the mutant cells. As these properties are typical characteristics of RNA chaperones, we conclude that AtUSP functions as a RNA chaperone under cold-shock conditions. Thus, the enhanced tolerance of AtUSP OE lines to cold stress is mediated by the RNA chaperone function of AtUSP
Anomalous Dimensionality-Driven Phase Transition of MoTe2 in Van der Waals Heterostructure
© 2021 Wiley-VCH GmbHPhase transition in nanomaterials is distinct from that in 3D bulk materials owing to the dominant contribution of surface energy. Among nanomaterials, 2D materials have shown unique phase transition behaviors due to their larger surface-to-volume ratio, high crystallinity, and lack of dangling bonds in atomically thin layers. Here, the anomalous dimensionality-driven phase transition of molybdenum ditelluride (MoTe2) encapsulated by hexagonal boron nitride (hBN) is reported. After encapsulation annealing, single-crystal 2H-MoTe2 transformed into polycrystalline Td-MoTe2 with tilt-angle grain boundaries of 60°-glide-reflection and 120°-twofold rotation. In contrast to conventional nanomaterials, the hBN-encapsulated MoTe2 exhibit a deterministic dependence of the phase transition on the number of layers, in which the thinner MoTe2 has a higher 2H-to-Td phase transition temperature. In addition, the vertical and lateral phase transitions of the stacked MoTe2 with different crystalline orientations can be controlled by inserted graphene layers and the thickness of the heterostructure. Finally, it is shown that seamless Td contacts for 2H-MoTe2 transistors can be fabricated by using the dimensionality-driven phase transition. The work provides insight into the phase transition of 2D materials and van der Waals heterostructures and illustrates a novel method for the fabrication of multi-phase 2D electronics.11Nsciescopu
Anomalous Dimensionality-Driven Phase Transition of MoTe2 in Van der Waals Heterostructure
Phase transition in nanomaterials is distinct from that in 3D bulk materials owing to the dominant contribution of surface energy. Among nanomaterials, 2D materials have shown unique phase transition behaviors due to their larger surface-to-volume ratio, high crystallinity, and lack of dangling bonds in atomically thin layers. Here, the anomalous dimensionality-driven phase transition of molybdenum ditelluride (MoTe2) encapsulated by hexagonal boron nitride (hBN) is reported. After encapsulation annealing, single-crystal 2H-MoTe2 transformed into polycrystalline T-d-MoTe2 with tilt-angle grain boundaries of 60 degrees-glide-reflection and 120 degrees-twofold rotation. In contrast to conventional nanomaterials, the hBN-encapsulated MoTe2 exhibit a deterministic dependence of the phase transition on the number of layers, in which the thinner MoTe2 has a higher 2H-to-T-d phase transition temperature. In addition, the vertical and lateral phase transitions of the stacked MoTe2 with different crystalline orientations can be controlled by inserted graphene layers and the thickness of the heterostructure. Finally, it is shown that seamless T-d contacts for 2H-MoTe2 transistors can be fabricated by using the dimensionality-driven phase transition. The work provides insight into the phase transition of 2D materials and van der Waals heterostructures and illustrates a novel method for the fabrication of multi-phase 2D electronics.N
HER-2/neu amplification is an independent prognostic factor in gastric cancer
The HER-2/neu protein is intimately involved with normal cell proliferation and tissue growth and is extensively homologous and related to the epidermal growth factor receptor. HER-2/neu protein expression has been most intensively studied in the context of breast carcinoma, in which its amplification and overexpression correlate with the overall course of disease, and with a poor prognosis, and constitute a predictive factor of poor response to chemotherapy and endocrine therapy. In this study, we investigated the relationship between the expression of HER-2/neu and the clinicopathological characteristics of tumors, including survival. This study was performed with a view toward the future introduction of Herceptin therapy for gastric cancer patients. HER-2/neu overexpression and gene amplification was examined with semiquantitative standardized immunohistochemical staining, chromogenic in situ hybridization (CISH), and fluorescence in situ hybridization (FISH) in 182 gastric cancer patients who underwent curative surgery at the Kangbuk Samsung Hospital. Twenty-nine (15.9%) of 182 patients expressed the HER-2/neu protein by immunohistochemistry. HER-2/neu gene amplification was detected in seven patients by CISH and FISH. Intestinal-type cancers exhibited higher rates of HER-2/neu amplification than did diffuse-type cancers (P \u3c 0.05). Tumors with HER-2/neu amplification were associated with poor mean survival rates (922 vs 3243 days) and 5-year survival rates (21.4% vs 63.0%; P \u3c 0.05). Age, TNM stage, and amplification of HER-2/neu were found to be independently related to survival by multivariate analysis. HER-2/neu amplification may constitute an independent prognostic factor in gastric cancer patients, and patients exhibiting HER-2/neu amplification might constitute potential candidates for new adjuvant therapies which involve the use of humanized monoclonal antibodies. © Springer Science+Business Media, Inc. 2006