53 research outputs found
CVD-grown monolayer MoS2 in bioabsorbable electronics and biosensors
Transient electronics entails the capability of electronic components to dissolve or reabsorb in a controlled manner when used in biomedical implants. Here, the authors perform a systematic study of the processes of hydrolysis, bioabsorption, cytotoxicity and immunological biocompatibility of monolayer MoS2
Enhanced Raman Scattering from Nanoparticle-Decorated Nanocone Substrates: A Practical Approach to Harness In-Plane Excitation
We investigate surface-enhanced Raman scattering (SERS) from gold-coated silicon-germanium
nanocone substrates that are decorated with 30-nm spherical gold nanoparticles (AuNPs). Finite-element
simulations suggest that individual nanocones generate stronger electromagnetic enhancement with axial
polarization (i.e., polarization parallel to the vertical axis of the nanocones) than with transverse polarization
(i.e., polarization in the plane of the nanocone substrate), whereas the excitation in a typical Raman microscope
is mainly polarized in the transverse plane. We introduce a practical approach to improve the SERS performance of
the substrate by filling the valleys between nanocones with AuNPs. Simulations reveal an enhanced electric field
at the nanoscale junctions formed between AuNPs and nanocones, and we explain this lateral coupling with a
hybridization model for a particle-film system. We further experimentally verify the added enhancement by
measuring SERS from trans-1,2-bi-(4-pyridyl) ethylene molecules absorbed onto the substrates. We report over
one order-of-magnitude increase in SERS activities with the AuNP decoration (compared to the nanocone substrate
without AuNPs) and achieve a spatially averaged enhancement factor of 1.78 x 10^8 at 785-nm excitation.
Understanding and implementing the enhancing mechanism of structured metallic surfaces decorated with
plasmonic nanoparticles open possibilities to substantially improve the SERS performance of the existing processengineered substrates
The effect of exopolysaccharides from EMS-induced Porphyridium cruentum mutant on human epidermal and dermal layers
IntroductionMicroalgae biotechnology utilizes species like Porphyridium cruentum for their valuable phycobiliproteins and exopolysaccharides, which have potential industrial applications and health benefits, particularly in skin condition improvement.MethodsA mutant of P. cruentum LIMS-PS-1061 was developed through ethyl methanesulfonate mutagenesis and subsequent colony screening to study changes in its biomass production and pigment composition under different lighting conditions.Results and discussionThe mutant exhibited a 33.9% increase in dry weight under white light compared to the wild type. Despite maintaining the total pigment content, specific components changed significantly: chlorophyll content decreased 2.20- and 3.61-fold under white and blue light respectively, while phycobiliproteins increased 1.59- and 1.23-fold under the same conditions. These alterations suggest a compensatory mechanism for maintaining photosynthetic capacity. Furthermore, the exopolysaccharides of P. cruentum upregulated genes related to skin moisturization, barrier enhancement, and elasticity, and promoted wound healing through fibroblast migration. This supports the proposed mechanism of action for P. cruentum’s exopolysaccharides in improving human skin conditions by integrating the effects of aquaporin 3, filaggrin, involucrin, loricrin, elastin, and fibrillin-1
Defective Localization With Impaired Tumor Cytotoxicity Contributes to the Immune Escape of NK Cells in Pancreatic Cancer Patients
Tumor-infiltrating lymphocytes (TILs), found in patients with advanced pancreatic ductal adenocarcinoma (PDAC), are shown to correlate with overall survival (OS) rate. Although majority of TILs consist of CD8+/CD4+ T cells, the presence of NK cells and their role in the pathogenesis of PDAC remains elusive. We performed comprehensive analyses of TIL, PBMC, and autologous tumor cells from 80 enrolled resectable PDAC patients to comprehend the NK cell defects within PDAC. Extremely low frequencies of NK cells (<0.5%) were found within PDAC tumors, which was attributable not to the low expression of tumor chemokines, but to the lack of chemokine receptor, CXCR2. Forced expression of CXCR2 in patients' NK cells rendered them capable of trafficking into PDAC. Furthermore, NK cells exhibited impaired cell-mediated killing of autologous PDAC cells, primarily due to insufficient ligation of NKG2D and DNAM-1, and failed to proliferate within the hypoxic tumor microenvironment. Importantly, these defects could be overcome by ex-vivo stimulation of NK cells from such patients. Importantly, when the proliferative capacity of NK cells in vitro was used to stratify patients on the basis of cell expansion, patients whose NK cells proliferated <250-fold experienced significantly lower DFS and OS than those with ≥250-fold. Ex-vivo activation of NK cells restored tumor trafficking and reactivity, hence provided a therapeutic modality while their fold expansion could be a potentially significant prognostic indicator of OS and DFS in such patients
The effect of leg length asymmetry on leg stiffness and dynamic postural stability in vertical landing
Background: Assessment of asymmetries in dynamic postural stability and lower extremities kinetics during landing technique are considered factors for injury prevention and achieve optimal athletic performance. Nevertheless, the relationship between these factors has not been established. This study aimed to investigate the effects of leg length asymmetry on dynamic stability and leg stiffness upon initial contact with the ground after vertical landing. Methods: Twenty healthy adult men landed on the ground from a height of 30 cm; we measured leg length, leg stiffness, lateral pelvic tilt angle, peak vertical force (PVF), the loading rate, dynamic postural stability index (DPSI), and the correlations among these variables. Results: At initial contact, the right leg was significantly longer and showed greater lateral pelvic tilt than the left leg. These characteristics increased the loading rate at the time of PVF on the right leg, which in turn affected leg stiffness and pelvic tilt. The DPSI was also decreased for the right leg compared with the left leg. In the correlation analysis, we observed strong, positive correlations and high explanatory power for PVF, the loading rate, vertical stability index, and DPSI, with r ≥0.822 and R2 ≥57%. Conclusions: The identified associations support the validity of the result, showing that the right leg failed in its rapid stabilization strategy. The leg length asymmetry is suspected to affect asymmetrical impact patterns, DPSI, and leg stiffness. Given the number of individuals with leg-length inequalities who play sports relying on jumping and landing patterns, reducing the rate of injury possibly incurred
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