Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive ...stars
, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars
. A third class of events with hybrid high-energy properties was identified
, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions
, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented
. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 10
erg per second) kilonova possibly formed in the ejecta of a compact object merger.
Polymer-infiltrated ceramic network (PICN) composites are mechanically compatible with human enamel, and are therefore promising dental restorative materials. Fabrication technology for PICN ...composites used in tooth restorative material has been established through computer-aided design/computer-aided manufacturing (CAD/CAM) milling, however, to date, has not been successfully developed using 3-dimensional (3D) printing. This study aimed to develop a 3D-printable PICN composite as a restorative material. The PICN composite was fabricated using a specific method based on 3D printing. A 3D-printable precursor slurry containing a high concentration of silica nanoparticles was produced and 3D-printed using stereolithography (SLA). The 3D-printed object was sintered to obtain a nano-porous object, and subsequently infiltrated and polymerized with resin monomer. Three different fabrication condition combinations were used to produce the 3D-printed PICN composites, which were characterized based on microstructure, mechanical properties, inorganic content, physicochemical properties, and overall shrinkage. The 3D-printed PICN composites were also compared to 2 commercially available CAD/CAM composite blocks, namely a PICN composite and a dispersed-filler composite. The 3D-printed PICN composites exhibited a nano-sized dual-network structure comprising a silica skeleton with infiltrated resin. The 3D-printed PICN composite exhibited a similar Vickers hardness to enamel, and a similar elastic modulus to dentin. The 3D-printed PICN composite exhibited comparable flexural strength (>100 MPa) to the CAD/CAM block, and acceptable water sorption and solubility for practical use. Further, the 3D-printed model-crown underwent isotropic shrinkage during sintering without fatal deformation. Overall, the potential of this 3D-printable PICN composite as a restorative material with similar mechanical properties to human teeth was successfully demonstrated.
Mucin in saliva plays a critical role in the hydration and lubrication of the oral mucosa by retaining water molecules, and its impaired function may be associated with hyposalivation-independent ...xerostomia. Age-dependent effects on salivary gland function and rheological properties of secreted saliva are not fully understood as aging is a complex and multifactorial process. We aimed to evaluate age-related changes in the rheological properties of saliva and elucidate the underlying mechanism. We performed ex vivo submandibular gland (SMG) and sublingual gland (SLG) perfusion experiments to collect saliva from isolated glands of young (12 wk old) and aged (27 mo old) female C57BL/6J mice and investigate the rheological properties by determining the spinnbarkeit (viscoelasticity). While fluid secretion was comparable in SMG and SLG of both mice, spinnbarkeit showed a significant decrease in SLG saliva of aged mice than that of young mice. There were no significant differences in GalNAc concentration between young and aged SLG saliva. Liquid chromatography/tandem mass spectrometry analysis of SLG saliva revealed that (Hex)1 (HexNAc)1 (NeuAc)1 at m/z 793.31 was the most abundant O-glycan structure in SLG saliva commonly detected in both mice. Lectin staining of salivary gland tissue showed that SLG stained strongly with Maackia amurensis lectin II (MAL II) while Sambucus nigra agglutinin (SNA) stained little, if any, SLG. The messenger RNA expression of St3gal1 that encodes an α-2,3 sialic acid sialyltransferase SIAT4-A showed a decrease in SLG of aged mice, confirmed by a Western blot analysis. Lectin blot analysis in SLG saliva revealed that the relative signal intensity detected by MAL II was significantly lower in aged SLG. Our results suggest that spinnbarkeit decreases in SLG of aging mice due to downregulation of sialic acid linked to α-2,3 sialic acid sialyltransferase expression.
Oral ulcer is the most common oral disease and leads to pain during meals and speaking, reducing the quality of life of patients. Recent evidence using animal models suggests that oral ulcers induce ...cyclooxygenase-dependent spontaneous pain and cyclooxygenase-independent mechanical allodynia. Endothelin-1 is upregulated in oral mucosal inflammation, although it has not been shown to induce pain in oral ulcers. In the present study, we investigated the involvement of endothelin-1 signaling with oral ulcer–induced pain using our proprietary assay system in conscious rats. Endothelin-1 was significantly upregulated in oral ulcers experimentally induced by topical acetic acid treatment, while endothelin-1 production was suppressed by antibacterial pretreatment. Spontaneous nociceptive behavior in oral ulcer model rats was inhibited by swab applications of BQ-788 (ETB receptor antagonist), ONO-8711 (prostanoid receptor EP1 antagonist), and HC-030031 (TRPA1 antagonist). Prostaglandin E2 production in the ulcers was suppressed by BQ-788. Mechanical allodynia in the model was inhibited not only by BQ-788 and HC-030031 but also by BQ-123 (ETA receptor antagonist), SB-366791 (TRPV1 antagonist), and RN-1734 (TRPV4 antagonist). In naive rats, submucosal injection of endothelin-1 caused mechanical allodynia that was sensitive to HC-030031 and SB-366791 but not to RN-1734. These results suggest that endothelin-1 production following oral bacterial invasion via ulcerative regions elicits TRPA1-mediated spontaneous pain. This pain likely occurs through an indirect route that involves ETB receptor-accelerated prostanoid production. Endothelin-1 elicits directly TRPA1- and TRPV1-mediated mechanical allodynia via both ETA and ETB receptors on nociceptive fibers. The TRPV4-mediated allodynia component seems to be independent of endothelin signaling. These findings highlight the potential of endothelin signaling blockers as effective analgesic approaches for oral ulcer patients.
Long lasting interaction >10ms between ruthenium dyes and iodine redox species in dye-sensitized solar cells.
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•Long-lived ruthenium-dye/iodine interaction were found.•The interaction ...continued for >20ms.•Similar interaction was found for a specific organic dye.•The bleach peak of dyes were blue-shifted.
Long-lived bleach responses with a lifetime of several milliseconds were found for the ruthenium and organic dyes in dye-sensitized solar cells. These responses were caused by the specific interaction between each dye and ionic species in the electrolyte. For the ruthenium and D131 dyes, iodide ions were necessary for the shift, while lithium cations induced it for D149, even though the molecular structure is quite similar for D131 and D149. The bleach peak was caused by the blue shift of the absorption peak even after the regeneration of the dye from the dye cation, which would be induced by the composition/concentration change of the ionic species on the electrolyte side due to the redox reactions or charge compensation. The result was confirmed by the dependence of the transient absorption spectra on the order from microsecond to millisecond on various anion and cation conditions, dye structures, and redox species.
The quality and quantity of mandibular bone are essential prerequisites for osseointegrated implants. Only the Hounsfield unit on preoperative computed tomography is currently used as a clinical ...index. Nevertheless, a considerable mismatch occurs between bone quality and the Hounsfield unit. Loss of bone toughness during aging has been accepted based on empirical evidence, but this concept is unlikely evidence based at the level of mechanical properties. Nonenzymatic bone matrix cross-links associated with advanced glycation end products predominate as a consequence of aging. Thus, loss of tissue integrity could diminish the bone toughening mechanism. Here, we demonstrate an impaired bone toughening mechanism caused by mimicking aging in rabbits on a methionine-rich diet, which enabled an enhanced nonenzymatically cross-linked bone matrix. A 3-point bending test revealed a greater reduction in femoral fracture resistance in rabbits on a methionine-rich diet, despite higher maximum and normalized breaking forces (287.3 N and 88.1%, respectively), than in rabbits on a normal diet (262.2 N and 79.7%, respectively). In situ nanoindentation on mandibular cortical bone obtained from rabbits on a methionine-rich diet did not enable strain rate–dependent stiffening and consequent large-dimensional recovery during rapid loading following constant displacement after a rapid-load indentation test as compared with those in rabbits on a normal diet. Such nanoscale structure-function relationships dictate resistance to cracking propagation at the material level and allow for the overall bone toughening mechanism to operate under large external stressors. The strain-dependent stiffening was likely associated with strain-energy transfer to the superior cross-linked bone matrix network of the normal diet, while the reduction in the enzymatically cross-linked matrix in bone samples from rabbits on a methionine-rich diet likely diminished the intrinsic bone toughening mechanism. The present study also provides a precise protocol for evaluating bone mechanical properties at the material level based on observations from a series of nanoindentation experiments.
Background and purpose: To estimate the diagnostic accuracy of cardiac 123I‐metaiodobenzylguanidine (MIBG) scintigram for detection of Parkinson disease.
Methods: A cross‐sectional study with index ...test of MIBG scintigram and reference standard of U.K. Parkinson’s Disease Brain Bank Criteria was performed in 403 patients. Ratio of cardiac‐to‐mediastinum MIBG accumulation was determined at 20 min (early H/M) and 4 h (late H/M). Area under the receiver‐operator characteristic (ROC) curve, sensitivity and specificity in detecting Parkinson disease were analyzed. Accuracy was analyzed in a subgroup of patients with disease duration of 3 years or less.
Results: Area under the ROC curve was 0.89 using either early or late H/M as a diagnostic marker (95% CI 0.85–0.92 for early H/M and 0.86–0.93 for late H/M). Sensitivity and specificity were 81.3% (76.1–85.8%) and 85.0% (77.7–90.6%) for early H/M and 84.3% (79.3–88.4%) and 89.5% (83.01–94.1%) for late H/M. In the subgroup with duration of 3 years or less, the ROC curve area, sensitivity, and specificity were 0.86 (0.79–0.92), 76.0% (64.8–85.1%), and 83.9% (71.7–92.4%) for early H/M and 0.85 (0.78–0.92), 73.3% (61.9–82.9%), and 87.5% (75.9–94.8%) for late H/M.
Conclusion: Although diagnostic accuracy of cardiac MIBG scintigram is high, it is limited because of insufficient sensitivity in patients with short duration.
Polyamide, PA, is a thermoplastic very used in practical applications once it associates a series of convenient properties. However, its affinity towards water promotes swelling and thus dimensional ...changes, a drawback for most of the applications. There exist alternative polymers but the fully bulk replacement is hindered by costs. In this sense, the modification of polymer surfaces using a versatile, simple and low cost methodology emerges as an important tool. In this work, low pressure plasmas were employed to adjust the surface properties of the commercial polyamide 6 aiming to decrease its affinity to water. Organosilicon films were deposited from hexamethyldisiloxane, HMDSO, oxygen and argon plasma mixtures. The plasma reactor was pumped down to 3.0Pa and HMDSO, oxygen and argon were admitted to the reactor establishing the pressure of 24Pa. In each one of the four deposition cycles, the HMDSO proportion was fixed at 70% while those of oxygen (0 to 30%) and argon (30 to 0%) were varied in opposite ways. The plasma was ignited by the application of radiofrequency power (13.56MHz, 150W) to the lowermost sample holder, earthening the top electrode. Deposition was conducted for 1800s. It was specifically investigated if the receptivity of the organosilicon film to water can be further reduced by adjusting its topography. Infrared spectroscopy was used to determine the molecular structure of the samples while water wettability was measured by the contact angle approach. Surface microstructure was inspected by scanning electron microscopy and atomic force microscopy. Elemental composition was derived from energy dispersive spectroscopy. Films are in general organosilicon with methyl functionals connected to the SiOSi backbone as lateral groups and/or chain termination in a more crosslinked way than the conventional silicone. A granular structure composed by agglomerates of different diameters was generated. Roughness is affected by the proportion of the dilution gases since it influences the deposition kinetics and then the rate of polymerization in the plasma phase. Independently of the oxygen and argon proportions used in the plasma polymerization process, the bare hydrophilic PA was converted into hydrophobic upon film deposition.
•Swelling of polyamide 6 under water vapor atmosphere: pieces in automobilistic/food industries•Modification of polymer surfaces using a versatile, simple and low cost methodology emerges as an important tool•Plasma deposited organosilicon films from HMDSO/O2/Ar mixtures•Hydrophobic, uniform and transparent films with barriers properties•Wettability dependence on molecular structure, morphology and topography.
We describe the details of a silicon–tungsten prototype electromagnetic calorimeter module and associated readout electronics. Detector performance for this prototype has been measured in test beam ...experiments at the CERN PS and SPS accelerator facilities in 2015/16. The results are compared to those in Monte Carlo Geant4 simulations. This is the first real-world demonstration of the performance of a custom ASIC designed for fast, lower-power, high-granularity applications.
Summary
To treat sleep bruxism (SB), symptomatic therapy using stabilisation splints (SS) is frequently used. However, their effects on psychological stress and sleep quality have not yet been ...examined fully. The objective of this study was to clarify the effects of SS use on psychological stress and sleep quality. The subjects (11 men, 12 women) were healthy volunteers. A crossover design was used. Sleep measurements were performed for three consecutive days or longer without (baseline) or with an SS or palatal splint (PS), and data for the final day were evaluated. We measured masseter muscle activity during sleep using portable electromyography to evaluate SB. Furthermore, to compare psychological stress before and after sleep, assessments were made based on STAI‐JYZ and the measurement of salivary chromogranin A. To compare each parameter among the three groups (baseline, SS and PS), Friedman's and Dunn's tests were used. From the results of the baseline measurements, eight subjects were identified as high group and 15 as low group. Among the high group, a marked decrease in the number of bruxism events per hour and an increase in the difference in the total STAI Y‐1 scores were observed in the SS group compared with those at baseline (P < 0·05). No significant difference was observed in sleep stages. SS use may be effective in reducing the number of SB events, while it may increase psychological stress levels, and SS use did not apparently influence sleep stages.
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