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Nature Communications May 2024In the absence of externally applied mechanical loading, it would seem counterintuitive that a solid particle sitting on the surface of another solid could not only sink...
In the absence of externally applied mechanical loading, it would seem counterintuitive that a solid particle sitting on the surface of another solid could not only sink into the latter, but also continue its rigid-body motion towards the interior, reaching a depth as distant as thousands of times the particle diameter. Here, we demonstrate such a case using in situ microscopic as well as bulk experiments, in which diamond nanoparticles ~100 nm in size move into iron up to millimeter depth, at a temperature about half of the melting point of iron. Each diamond nanoparticle is nudged as a whole, in a displacive motion towards the iron interior, due to a local stress induced by the accumulation of iron atoms diffusing around the particle via a short and easy interfacial channel. Our discovery underscores an unusual mass transport mode in solids, in addition to the familiar diffusion of individual atoms.
PubMed: 38821939
DOI: 10.1038/s41467-024-48692-5 -
Langmuir : the ACS Journal of Surfaces... Jun 2024Chitosan is a product of deacetylated chitin and a natural polymer that is attractive as a functional and biocompatible material in the pursuit of alternative materials...
Chitosan is a product of deacetylated chitin and a natural polymer that is attractive as a functional and biocompatible material in the pursuit of alternative materials to synthetic plastics for a sustainable society. Although hierarchical architectures, from precise molecular structures to nanofibers and twisted structures, have been clarified, the expansion of the anisotropic microstructures of chitosan into millimeter-scale materials is in the process of development. In this study, a chitosan network was reconstructed from an aqueous solution by using the meniscus splitting method to form a three-dimensionally ordered microstructure. A chitosan membrane deposited on the millimeter scale formed a useful anisotropically pH-responsive hydrogel. During the evaporation of the aqueous solution from a finite space, chitosan underwent ordered deposition by capillary force to form a membrane with oriented microstructures and microlayers. Unlike the cast films formed between solid-liquid and air-liquid interfaces, this membrane formed between two air-liquid interfaces. As a result, the membranes with ordered microstructures were capable of signifying directional swelling in aqueous environments and reversible/irreversible swelling-deswelling changes by controlling the pH range. We envision that the anisotropic pH response of the chitosan network can be utilized under physiological conditions as a next-generation material.
PubMed: 38821491
DOI: 10.1021/acs.langmuir.4c00273 -
Science Advances May 2024The ability of cells to organize into tissues with proper structure and function requires the effective coordination of proliferation, migration, polarization, and...
The ability of cells to organize into tissues with proper structure and function requires the effective coordination of proliferation, migration, polarization, and differentiation across length scales. Skeletal muscle is innately anisotropic; however, few biomaterials can emulate mechanical anisotropy to determine its influence on tissue patterning without introducing confounding topography. Here, we demonstrate that substrate stiffness anisotropy coordinates contractility-driven collective cellular dynamics resulting in C2C12 myotube alignment over millimeter-scale distances. When cultured on mechanically anisotropic liquid crystalline polymer networks (LCNs) lacking topography, C2C12 myoblasts collectively polarize in the stiffest direction. Cellular coordination is amplified through reciprocal cell-ECM dynamics that emerge during fusion, driving global myotube-ECM ordering. Conversely, myotube alignment was restricted to small local domains with no directional preference on mechanically isotropic LCNs of the same chemical formulation. These findings provide valuable insights for designing biomaterials that mimic anisotropic microenvironments and underscore the importance of stiffness anisotropy in orchestrating tissue morphogenesis.
Topics: Anisotropy; Animals; Muscle Fibers, Skeletal; Mice; Extracellular Matrix; Cell Line; Cell Differentiation; Muscle Contraction; Myoblasts
PubMed: 38820155
DOI: 10.1126/sciadv.adn0235 -
3D Printing in Medicine May 20243D-printed temporal bone models enable the training and rehearsal of complex otological procedures. To date, there has been no consolidation of the literature regarding...
INTRODUCTION
3D-printed temporal bone models enable the training and rehearsal of complex otological procedures. To date, there has been no consolidation of the literature regarding the developmental process of 3D-printed temporal bone models. A brief review of the current literature shows that many of the key surgical landmarks of the temporal bone are poorly represented in models. This study aims to propose a novel design and production workflow to produce high-fidelity 3D-printed temporal bone models for surgical simulation.
METHODS
Developmental phases for data extraction, 3D segmentation and Computer Aided Design (CAD), and fabrication are outlined. The design and fabrication considerations for key anatomical regions, such as the mastoid air cells and course of the facial nerve, are expounded on with the associated strategy and design methods employed. To validate the model, radiological measurements were compared and a senior otolaryngologist performed various surgical procedures on the model.
RESULTS
Measurements between the original scans and scans of the model demonstrate sub-millimetre accuracy of the model. Assessment by the senior otologist found that the model was satisfactory in simulating multiple surgical procedures.
CONCLUSION
This study offers a systematic method for creating accurate 3D-printed temporal bone models for surgical training. Results show high accuracy and effectiveness in simulating surgical procedures, promising improved training and patient outcomes.
PubMed: 38814431
DOI: 10.1186/s41205-024-00218-x -
Communications Chemistry May 2024Quasi-liquid layers (QLLs) are present on the surface of ice and play a significant role in its distinctive chemical and physical properties. These layers exhibit...
Quasi-liquid layers (QLLs) are present on the surface of ice and play a significant role in its distinctive chemical and physical properties. These layers exhibit considerable heterogeneity across different scales ranging from nanometers to millimeters. Although the formation of partially ice-like structures has been proposed, the molecular-level understanding of this heterogeneity remains unclear. Here, we examined the heterogeneity of molecular dynamics on QLLs based on molecular dynamics simulations and machine learning analysis of the simulation data. We demonstrated that the molecular dynamics of QLLs do not comprise a mixture of solid- and liquid water molecules. Rather, molecules having similar behaviors form dynamical domains that are associated with the dynamical heterogeneity of supercooled water. Nonetheless, molecules in the domains frequently switch their dynamical state. Furthermore, while there is no observable characteristic domain size, the long-range ordering strongly depends on the temperature and crystal face. Instead of a mixture of static solid- and liquid-like regions, our results indicate the presence of heterogeneous molecular dynamics in QLLs, which offers molecular-level insights into the surface properties of ice.
PubMed: 38811834
DOI: 10.1038/s42004-024-01197-0 -
Caspian Journal of Internal Medicine 2024With the improvement of cancer treatment methods and increased life expectancy of patients, the prevalence of second primary cancers has gradually increased.
BACKGROUND
With the improvement of cancer treatment methods and increased life expectancy of patients, the prevalence of second primary cancers has gradually increased.
CASE PRESENTATION
In the present study, the case was a 58-year-old man diagnosed with rectal adenocarcinoma and underwent chemotherapy and neoadjuvant radiotherapy 10 years ago. After 5 years, he underwent a lobectomy due to lung metastasis. At the research time, he presented with itching; in ERCP, a 16-millimeter hypoechoic lesion was detected, and an FNA biopsy was performed, indicating malignancy. The patient underwent Whipple surgery, and pathology revealed a well-differentiated neuroendocrine tumor. He was discharged in good general condition.
CONCLUSION
This article emphasized the necessity of early detection and diagnosis of second primary cancer, as well as acting as if it was primary cancer to treat.
PubMed: 38807717
DOI: 10.22088/cjim.15.2.360 -
Scientific Reports May 2024This paper presents a frequency selective surface (FSS) with a wideband second-order bandpass response in the dual-band of microwave and millimeter wave. The overall...
This paper presents a frequency selective surface (FSS) with a wideband second-order bandpass response in the dual-band of microwave and millimeter wave. The overall structure consists of three layers of metal pattern and two layers of thin dielectric substrate. The top and bottom metal layers have capacitive patches with integrated curled Jerusalem cross slot resonators, while the intermediate metal layer has an inductive grid structure with cross-shaped slot resonators. The incorporated slot resonators play a pivotal role in achieving the desired transmission poles or zeros, which enable a wideband second-order filtering response in the dual-band and a quick roll-off at the passband edges, increasing the efficacy of electromagnetic shielding. To fully investigate the structure's frequency response, an equivalent circuit model of the structure is created, spanning the complete frequency range of 5-50 GHz. Physical samples are created and measured to confirm the suggested approach's efficacy. The passband center frequencies of the FSS are found at f = 19.42 GHz and f = 42.78 GHz, and the - 3 dB bandwidth is 4.34 GHz (17.25-21.59 GHz) and 8.54 GHz (38.51-47.05 GHz), respectively. The simulation results align well with the experimental data. The transmission response rapidly transitions from the passband to the stopband at the passband boundaries.
PubMed: 38802498
DOI: 10.1038/s41598-024-62228-3 -
Nature Communications May 2024Maintaining the surface transparency of protective covers using transparent heaters in extreme weather is imperative for enhancing safety in autonomous driving. However,...
Maintaining the surface transparency of protective covers using transparent heaters in extreme weather is imperative for enhancing safety in autonomous driving. However, achieving both high transmittance and low sheet resistance, two key performance indicators for transparent heaters, is inherently challenging. Here, inspired by metamaterial design, we report microwave-transparent, low-sheet-resistance heaters for automotive radars. Ultrathin (approximately one ten-thousandth of the wavelength), electrically connected metamaterials on a millimetre-thick dielectric cover provide near-unity transmission at specific frequencies within the W band (75-110 GHz), despite their metal filling ratio exceeding 70 %. These metamaterials yield the desired phase delay to adjust Fabry-Perot resonance at each target frequency. Fabricated microwave-transparent heaters exhibit exceptionally low sheet resistance (0.41 ohm/sq), thereby heating the dielectric cover above 180 °C at a nominal bias of 3 V. Defrosting tests demonstrate their thermal capability to swiftly remove thin ice layers in sub-zero temperatures.
PubMed: 38802433
DOI: 10.1038/s41467-024-49001-w -
Scientific Reports May 2024Breccia and pulverized rock are typical textures in off-fault damage adjacent to a main seismogenic zone. Previously, by estimating the energy required to advance the...
Breccia and pulverized rock are typical textures in off-fault damage adjacent to a main seismogenic zone. Previously, by estimating the energy required to advance the rupture in this zone using particle size distribution at sub-millimeter/micrometer scales, we could constrain the energy budget during coseismic events. However, whether microscopic estimation is sufficient to capture surface energy fragmentation during an earthquake and the effect of measurement scale variation on calculation of co-seismic energy partitioning remained unclear. Here, we investigated the mechanism of coseismic off-fault damage based on field and microstructural observations of a well-exposed breccia body in Ichinokawa, Japan. We used in situ clast measurements coupled with thin-section analysis of breccia clasts to estimate the energy budget of the damage zone adjacent to the principal slip zone of the Median Tectonic Line (MTL). The total surface energy density and corresponding surface energy per unit fault for a width of ~ 500 m of the dynamical damage zone were estimated. The moment magnitude estimated based on surface energy was 5.8-8.3 Mw. In Ichinokawa, off-fault fragmentation is initiated by coseismic activity and is followed by fluid activity. Under dynamic fragmentation conditions, the scale is important to calculate the surface energy.
PubMed: 38802417
DOI: 10.1038/s41598-024-62838-x -
The Western Journal of Emergency... May 2024Ectopic pregnancies are a significant cause of morbidity and mortality in the first trimester of pregnancy. Hospital protocols requiring a specific beta-human chorionic...
INTRODUCTION
Ectopic pregnancies are a significant cause of morbidity and mortality in the first trimester of pregnancy. Hospital protocols requiring a specific beta-human chorionic gonadotropin (β-hCG) level to qualify for diagnostic testing (pelvic ultrasound) can delay diagnosis and treatment. In this study we sought to determine the relationship between β-hCG level and the size of ectopic pregnancy with associated outcomes.
METHODS
We performed a retrospective case review of patients diagnosed with ectopic pregnancy in an urban, academic emergency department specializing in obstetrical care, from January 1, 2015-December 31, 2017. Variables extracted included presentation, treatment, adverse outcomes, and rates of rupture.
RESULTS
We identified 519 unique ectopic pregnancies. Of those ectopic pregnancies, 22.9% presented with evidence of rupture on ultrasound, and 14.4% showed evidence of hemodynamic instability (pulse >100 beats per minute; systolic blood pressure <90 millimeters of mercury; or evidence of significant blood loss) on presentation. Medical management outcomes were as follows: of 177 patients who received single-dose methotrexate, 14.7% failed medical management and required surgical intervention; of 46 who received multi-dose methotrexate, 36.9% failed medical management and required surgical intervention. Ultimately, 55.7% of patients required operative management of their ectopic pregnancy. Mean β-hCG level at initial presentation was 7,096 milli-international units per milliliter (mIU/mL) (SD 88,872 mIU/mL) with a median of 1,289 mIU/mL; 50.4% of ectopic pregnancies presented with β-hCG levels less than the standard discriminatory zone of 1,500 mIU/mL. Additionally, 44% of the patients who presented with evidence of rupture had β-hCG levels less than 1,500 mIU/mL. Comparison of size of ectopic pregnancy (based on maximum dimension in millimeters) to β-hCG levels revealed a very weak correlation (r = 0.144, ), and detection of ectopic pregnancies by ultrasound was independent of β-hCG levels.
CONCLUSION
Levels of β-hCG do not correlate with the presence or size of an ectopic pregnancy, indicating need for diagnostic imaging regardless of β-hCG level in patients with clinical suspicion for ectopic pregnancy. Almost one-sixth of patients presented with evidence of hemodynamic instability, and approximately one quarter of patients presented with evidence of rupture requiring emergent operative management. Ultimately, more than half of patients required an operative procedure to definitively manage their ectopic pregnancy.
Topics: Humans; Female; Pregnancy; Pregnancy, Ectopic; Retrospective Studies; Chorionic Gonadotropin, beta Subunit, Human; Adult; Emergency Service, Hospital; Methotrexate; Abortifacient Agents, Nonsteroidal; Pregnancy Trimester, First; Ultrasonography, Prenatal
PubMed: 38801051
DOI: 10.5811/westjem.18396