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1.
Microsyst Nanoeng ; 10: 48, 2024.
Article in English | MEDLINE | ID: mdl-38590817

ABSTRACT

Double-sided microlens arrays (DSMLAs) include combinations of two single-sided MLAs to overcome positioning errors and greatly improve light transmissivity compared to other types of lenses. Precision glass molding (PGM) is used to fabricate DSMLAs, but controlling alignment errors during this process is challenging. In this paper, a mold assembly was manufactured with a novel combination of materials to improve the alignment accuracy of mold cores during PGM by using the nonlinear thermal expansion characteristics of the various materials to improve the DSMLA alignment accuracy. By establishing a mathematical model of the DSMLA alignment error and a thermal expansion model of the mold-sleeve pair, the relationship between the maximum alignment error of the DSMLA and the mold-sleeve gap was determined. This research provides a method to optimize the mold-sleeve gap and minimize the alignment error of the DSMLA. The measured DSMLA alignment error was 10.56 µm, which is similar to the predicted maximum alignment error. Optical measurements showed that the uniformity of the homogenized beam spot was 97.81%, and the effective homogeneous area accounted for 91.66% of the total area. This proposed method provides a novel strategy to improve the performance of DSMLAs.

2.
Anim Biosci ; 37(6): 1041-1052, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38419535

ABSTRACT

OBJECTIVE: Bacillus subtilis, a kind of probiotic with broad-spectrum antibacterial function, was commonly used in livestock and poultry production. Recent research suggested that Bacillus subtilis may have antioxidant properties and improve immune response. This study aimed to verify the probiotic function of Bacillus subtilis in the production of broiler chickens. METHODS: A total of 324 (1-day-old) Arbor Acres broilers were selected and randomly divided into three groups: basal diet group (Ctr Group), basal diet + antibiotic growth promoter group (Ctr + AGP) and basal diet + 0.5% Bacillus subtilis preparation group (Ctr + Bac). The experiment lasted for 42 days. Muscle, serum and liver samples were collected at 42 days for determination. RESULTS: The results showed that Bacillus subtilis could decrease malondialdehyde content in the serum and liver (p<0.05) and increase superoxide dismutase 1 mRNA expression (p<0.01) and total superoxide dismutase (p<0.05) in the liver. In addition, compared with AGP supplementation, Bacillus subtilis supplementation increased interleukin-10 (IL-10) and decreased tumor necrosis factor-α and IL-1ß level in the serum (p<0.05). At 45 minutes after slaughter Ctr + Bac presented a higher a* value of breast muscle than Ctr Group (p<0.05), while significant change in leg muscle was not identified. Moreover, there was no difference in weight, shear force, cooking loss and drip loss of breast and leg muscle between treatments. CONCLUSION: Our results demonstrate that Bacillus subtilis in diet can enhance antioxidant capacity and optimize immune response of broilers.

3.
Microbiol Spectr ; 12(1): e0109023, 2024 Jan 11.
Article in English | MEDLINE | ID: mdl-38018973

ABSTRACT

IMPORTANCE: HAdV-3, -7, and -55 are the predominant types causing acute respiratory disease outbreaks and can lead to severe and fatal pneumonia in children and adults. In recent years, emerging or re-emerging strains of HAdV-7 and HAdV-55 have caused multiple outbreaks globally in both civilian and military populations, drawing increased attention. Clinical studies have reported that HAdV-7 and HAdV-55 cause more severe pneumonia than HAdV-3. This study aimed to investigate the mechanisms explaining the higher severity of HAdV-7 and HAdV-55 infection compared to HAdV-3 infection. Our findings provided evidence linking the receptor-binding protein fiber to stronger infectivity of the strains mentioned above by comparing several fiber-chimeric or fiber-replaced adenoviruses. Our study improves our understanding of adenovirus infection and highlights potential implications, including in novel vector and vaccine development.


Subject(s)
Adenovirus Infections, Human , Adenoviruses, Human , Pneumonia , Respiratory Tract Infections , Child , Adult , Humans , Virulence
4.
Soft Matter ; 19(45): 8863-8870, 2023 Nov 22.
Article in English | MEDLINE | ID: mdl-37955055

ABSTRACT

We study the nematic-to-isotropic phase transitions in thin slabs of nematic liquid crystals with photopatterned director fields of topological defect arrays at constant heating rates and show that the transition kinetics is significantly impacted by both the heating rate and the topological strengths of these defects. Specifically, with ±1/2 defect arrays, the isotropic domains emerge from the defect cores when the heating rate is high, while from random places when the heating rate is low. With ±1 defect arrays, the isotropic domains always emerge from the defect cores regardless of the heating rate. Furthermore, the isotropic domains show significant movements at slow heating rates, and the total area of the isotropic domains grows with the temperature T following a simple power law (T - T')γ, where the exponent γ is approximately 1 in most cases and is 2/3 for the ±1 defect arrays at low heating rates when the isotropic domains are pinned on the defect cores. We attribute this phenomenon to an interplay between the surface tension and bulk free energy.

5.
EMBO Rep ; 24(4): e55971, 2023 04 05.
Article in English | MEDLINE | ID: mdl-36856136

ABSTRACT

Pseudomonas aeruginosa is a Gram-negative bacterium causing morbidity and mortality in immuno-compromised humans. It produces a lectin, LecB, that is considered a major virulence factor, however, its impact on the immune system remains incompletely understood. Here we show that LecB binds to endothelial cells in human skin and mice and disrupts the transendothelial passage of leukocytes in vitro. It impairs the migration of dendritic cells into the paracortex of lymph nodes leading to a reduced antigen-specific T cell response. Under the effect of the lectin, endothelial cells undergo profound cellular changes resulting in endocytosis and degradation of the junctional protein VE-cadherin, formation of an actin rim, and arrested cell motility. This likely negatively impacts the capacity of endothelial cells to respond to extracellular stimuli and to generate the intercellular gaps for allowing leukocyte diapedesis. A LecB inhibitor can restore dendritic cell migration and T cell activation, underlining the importance of LecB antagonism to reactivate the immune response against P. aeruginosa infection.


Subject(s)
Pseudomonas aeruginosa , Transendothelial and Transepithelial Migration , Humans , Animals , Mice , Endothelial Cells/metabolism , Lectins/metabolism , Lectins/pharmacology , Immunity
6.
J Neurosurg Pediatr ; 31(4): 290-297, 2023 04 01.
Article in English | MEDLINE | ID: mdl-36670533

ABSTRACT

OBJECTIVE: Intraoperative blood loss is a major challenge in pediatric brain tumor removal. Several clinical and surgical factors may influence the occurrence of intraoperative blood loss and blood transfusion. This study aimed to identify the risk factors of intraoperative blood loss and intraoperative red blood cell (RBC) transfusion for pediatric patients undergoing brain tumor removal. METHODS: A total of 297 pediatric patients undergoing brain tumor removal were selected in this retrospective, singlecenter study. Demographic data, laboratory data, imaging data, and surgical records were collected, and then independent risk factors for intraoperative blood loss and transfusion were identified using multivariate stepwise regression analysis. RESULTS: The median intraoperative blood loss in our cohort was 23.1 ml/kg (IQR 10.0-60.0 ml/kg). In total, 284 (95.6%) patients received intraoperative RBC transfusion, with a median amount of 0.2 U/kg (IQR 0.0-2.6 U/kg). Age (ß = -0.189; 95% CI [-1.359, -0.473]; p < 0.001); preoperative hemoglobin level (ß = -0.141; 95% CI [-1.528, -0.332]; p = 0.003); anesthesia time (ß = 0.189; 95% CI [0.098, 0.302]; p < 0.001); unclear tumor boundary (ß = 0.100; 95% CI [2.067, 41.053]; p = 0.031); tumor size (ß = 0.390; 95% CI [14.706, 24.342]; p < 0.001); and intraoperative continuous infusion of vasopressor (ß = 0.155; 95% CI [13.364, 52.400]; p = 0.001) were independent predictors of intraoperative blood loss. Independent predictors of the need for RBC transfusion included age (ß = -0.268; 95% CI [-0.007, -0.004]; p < 0.001); preoperative hemoglobin level (ß = -0.117; 95% CI [-0.005, -0.001]; p = 0.003); anesthesia time (ß = 0.221; 95% CI [0.001, 0.001]; p < 0.001); unclear tumor boundary (ß = 0.110; 95% CI [0.024, 0.167]; p = 0.010); tumor size (ß = 0.370; 95% CI [0.056, 0.092]; p < 0.001); intraoperative continuous infusion of vasopressor (ß = 0.157; 95% CI [0.062, 0.205]; p < 0.001); and tumor grade (ß = 0.107; 95% CI [0.007, 0.062]; p = 0.014). CONCLUSIONS: Overall, age, preoperative hemoglobin, tumor size, anesthesia time, continuous infusion of vasopressors, and unclear tumor boundary were the main determinants for intraoperative blood loss and RBC transfusion in pediatric patients undergoing brain tumor removal. Clinical trial registration no.: ChiCTR1900024803 (ChiCTR.org).


Subject(s)
Blood Loss, Surgical , Brain Neoplasms , Humans , Child , Retrospective Studies , Blood Transfusion , Brain Neoplasms/surgery , Risk Factors , Hemoglobins/analysis
7.
Methods ; 207: 65-73, 2022 11.
Article in English | MEDLINE | ID: mdl-36122881

ABSTRACT

Abnormal co-occurrence medical visit behavior is a form of medical insurance fraud. Specifically, an organized gang of fraudsters hold multiple medical insurance cards and purchase similar drugs frequently at the same time and the same location in order to siphon off medical insurance funds. Conventional identification methods to identify such behaviors rely mainly on manual auditing, making it difficult to satisfy the needs of identifying the small number of fraudulent behaviors in the large-scale medical data. On the other hand, the existing single-view bi-clustering algorithms only consider the features of the time-location dimension while neglecting the similarities in prescriptions and neglecting the fact that fraudsters may belong to multiple gangs. Therefore, in this paper, we present a multi-view bi-clustering method for identifying abnormal co-occurrence medical visit behavioral patterns, which performs cluster analysis simultaneously on the large-scale, complex and diverse visiting record dimension and prescription dimension to identify bi-clusters with similar time-location features. The proposed method constructs a matrix view of patients and visit records as well as a matrix view of patients and prescriptions, while decomposing multiple data matrices into sparse row and column vectors to obtain a consistent patient population across views. Subsequently the proposed method identifies the corresponding abnormal co-occurrence medical visit behavior and may greatly facilitate the safe operations and the sustainability of medical insurance funds. The experimental results show that our proposed method leads to more efficient and more accurate identifications of abnormal co-occurrence medical visit behavior, demonstrating its high efficiency and effectiveness.


Subject(s)
Algorithms , Humans , Cluster Analysis
8.
Article in English | MEDLINE | ID: mdl-36012090

ABSTRACT

Air purifiers should pay much attention to hospital-associated infections, but the role of a single air purifier is limited. The goal of this study was to evaluate the effectiveness of the combined application of the nonequilibrium positive and negative oxygen ion purifier (PNOI) and the high-efficiency particulate air filter (HEPA) on a complex, polluted environment. Two of the better performing purifiers were selected before the study. The efficacy of their use alone and in combination for purification of cigarette particulate matter (PM), Staphylococcus albicans, and influenza virus were then evaluated under a simulated contaminated ward. PNAI and HEPA alone are deficient. However, when they were combined, they achieved 98.44%, 99.75%, and 100% 30 min purification rates for cigarette PM, S. albus, and influenza virus, respectively. The purification of pollution of various particle sizes and positions was optimized and reduced differentials, and a subset of airborne influenza viruses is inactivated. Furthermore, they were superior to ultraviolet disinfection for microbial purification in air. This work demonstrates the strong purification capability of the combined application of these two air purifiers for complex air pollution, which provides a new idea for infection control in medical institutions.


Subject(s)
Air Filters , Air Pollutants , Air Pollution, Indoor , Orthomyxoviridae , Air Pollutants/analysis , Air Pollution, Indoor/analysis , Bacteria , Dust , Hospitals , Particulate Matter/analysis
9.
Sci Total Environ ; 845: 157252, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-35817112

ABSTRACT

Endosulfan belongs to persistent organic pollutants (POPs), closely related to an increased risk of prostate cancer (PCa). The existing evidence shows that lncRNAs compete with miRNAs for binding sites and contribute to the onset and progression of human malignancies. In this study we investigate how endosulfan promotes cell migration and invasion in DU145 and PC3 prostate cancer cells through epigenetic mechanism of lncRNA-miRNA regulation. Based on our past research we focused on PTP4A3 and constructed wild-type (WT) and mutant PTP4A3 plasmids for further analysis. Our results revealed that transfection of PTP4A3-WT can lead to changes in the expression of epithelial-mesenchymal transition (EMT) biomarkers and critical proteins in the TGF-ß signaling pathway, and promote cell migration and invasion in PCa cells. Bioinformatics analysis shows that there were complementary sequences in PTP4A3 3'-UTR and KCNQ1OT1 3'-UTR to the seed sequence of hsa-miR-137-3p, and dual luciferase reporter assay indicates the potential binding capacity of miR-137-3p to 3'-UTR of PTP4A3 and KCNQ1OT1. We found that miR-137-3p mimic inhibited cell migration and invasion, as well as repressed alterations of EMT biomarkers and critical proteins in the TGF-ß signaling pathway. Rescue experiment results revealed that co-transfection of miR-137-3p mimic and PTP4A3-WT plasmid reversed these changes following transfection with miR-137-3p mimic alone. We found that KCNQ1OT1 was predominantly distributed in the cytoplasm from a subcellular fractionation assay. Functionally, silencing of KCNQ1OT1 repressed cell migration and invasion, and caused alterations of EMT biomarkers and critical proteins in the TGF-ß signaling pathway, which were all restored by co-transfection with anti-miR-137-3p or PTP4A3-WT plasmid. Furthermore, overexpression of miR-137-3p or silencing of KCNQ1OT1 dramatically rescued the effects of endosulfan on promoting cell migration and invasion. These findings suggest that endosulfan can indeed promote cell migration and invasion via the KCNQ1OT1/miR-137-3p/PTP4A3 axis in PCa cells.


Subject(s)
MicroRNAs , Prostatic Neoplasms , Protein Tyrosine Phosphatases , RNA, Long Noncoding , Cell Line, Tumor , Cell Movement , Cell Proliferation , Endosulfan/toxicity , Humans , Male , MicroRNAs/genetics , Neoplasm Proteins/genetics , Potassium Channels, Voltage-Gated , Protein Tyrosine Phosphatases/genetics , RNA, Long Noncoding/genetics , Transforming Growth Factor beta/metabolism
10.
mBio ; 13(3): e0081922, 2022 06 28.
Article in English | MEDLINE | ID: mdl-35491830

ABSTRACT

The opportunistic bacterium Pseudomonas aeruginosa can infect mucosal tissues of the human body. To persist at the mucosal barrier, this highly adaptable pathogen has evolved many strategies, including invasion of host cells. Here, we show that the P. aeruginosa lectin LecB binds and cross-links fucosylated receptors at the apical plasma membrane of epithelial cells. This triggers a signaling cascade via Src kinases and phosphoinositide 3-kinase (PI3K), leading to the formation of patches enriched with the basolateral marker phosphatidylinositol (3,4,5)-trisphosphate (PIP3) at the apical plasma membrane. This identifies LecB as a causative bacterial factor for activating this well-known host cell response that is elicited upon apical binding of P. aeruginosa. Downstream from PI3K, Rac1 is activated to cause actin rearrangement and the outgrowth of protrusions at the apical plasma membrane. LecB-triggered PI3K activation also results in aberrant recruitment of caveolin-1 to the apical domain. In addition, we reveal a positive feedback loop between PI3K activation and apical caveolin-1 recruitment, which provides a mechanistic explanation for the previously observed implication of caveolin-1 in P. aeruginosa host cell invasion. Interestingly, LecB treatment also reversibly removes primary cilia. To directly prove the role of LecB for bacterial uptake, we coated bacterium-sized beads with LecB, which drastically enhanced their endocytosis. Furthermore, LecB deletion and LecB inhibition with l-fucose diminished the invasion efficiency of P. aeruginosa bacteria. Taken together, the results of our study identify LecB as a missing link that can explain how PI3K signaling and caveolin-1 recruitment are triggered to facilitate invasion of epithelial cells from the apical side by P. aeruginosa. IMPORTANCE An intriguing feature of the bacterium P. aeruginosa is its ability to colonize highly diverse niches. P. aeruginosa can, besides forming biofilms, also enter and proliferate within epithelial host cells. Moreover, research during recent years has shown that P. aeruginosa possesses many different mechanisms to invade host cells. In this study, we identify LecB as a novel invasion factor. In particular, we show that LecB activates PI3K signaling, which is connected via a positive feedback loop to apical caveolin-1 recruitment and leads to actin rearrangement at the apical plasma membrane. This provides a unifying explanation for the previously reported implication of PI3K and caveolin-1 in host cell invasion by P. aeruginosa. In addition, our study adds a further function to the remarkable repertoire of the lectin LecB, which is all brought about by the capability of LecB to recognize fucosylated glycans on many different niche-specific host cell receptors.


Subject(s)
Lectins , Pseudomonas aeruginosa , Actins/metabolism , Caveolin 1/metabolism , Cell Membrane/metabolism , Humans , Lectins/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Pseudomonas aeruginosa/metabolism
11.
Nat Commun ; 12(1): 5936, 2021 Oct 12.
Article in English | MEDLINE | ID: mdl-34642352

ABSTRACT

Liquid crystal elastomers exhibit large reversible strain and programmable shape transformations, enabling various applications in soft robotics, dynamic optics, and programmable origami and kirigami. The morphing modes of these materials depend on both their geometries and director fields. In two dimensions, a pixel-by-pixel design has been accomplished to attain more flexibility over the spatial resolution of the liquid crystal response. Here we generalize this idea in two steps. First, we create independent, cubic light-responsive voxels, each with a predefined director field orientation. Second, these voxels are in turn assembled to form lines, grids, or skeletal structures that would be rather difficult to obtain from an initially connected material sample. In this way, the orientation of the director fields can be made to vary at voxel resolution to allow for programmable optically- or thermally-triggered anisotropic or heterogeneous material responses and morphology changes in three dimensions that would be impossible or hard to implement otherwise.

12.
Adv Mater ; 33(38): e2104807, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34337803

ABSTRACT

Understanding the origin of structural ordering in supercooled liquid gallium (Ga) has been a great scientific quest in the past decades. Here, reflective polarized optical microscopy on Ga sandwiched between glasses treated with rubbed polymers reveals the onset of an anisotropic reflection at 120 °C that increases on cooling and persists down to room temperature or below. The polymer rubbing usually aligns the director of thermotropic liquid crystals (LCs) parallel to the rubbing direction. On the other hand, when Ga is sandwiched between substrates that align conventional LC molecules normal to the surface, the reflection is isotropic, but mechanical shear force induces anisotropic reflection that relaxes in seconds. Such alignment effects and shear-induced realignment are typical to conventional thermotropic LCs and indicate a LC structure of liquid Ga. Specifically, Ga textures obtained by atomic force and scanning electron microscopy reveal the existence of a lamellar structure corresponding to a smectic LC phase, while the nanometer-thin lamellar structure is transparent under transmission polarized optical microscopy. Such spatial molecular arrangements may be attributed to dimer molecular entities in the supercooled liquid Ga. The LC structure observation of electrically conductive liquid Ga can provide new opportunities in materials science and LC applications.

13.
Adv Mater ; 33(25): e2008605, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33987863

ABSTRACT

Programmable actuation of metastructures with predesigned geometrical configurations has recently drawn significant attention in many applications, such as smart structures, medical devices, soft robotics, prosthetics, and wearable devices. Despite remarkable progress in this field, achieving wireless miniaturized reconfigurable metastructures remains a challenge due to the difficult nature of the fabrication and actuation processes at the micrometer scale. Herein, microscale thermo-responsive reconfigurable metasurfaces using stimuli-responsive liquid crystal elastomers (LCEs) is fabricated as an artificial muscle for reconfiguring the 2D microscale kirigami structures. Such structures are fabricated via two-photon polymerization with sub-micrometer precision. Through rationally designed experiments guided by simulations, the optimal formulation of the LCE artificial muscle is explored and the relationship between shape transformation behaviors and geometrical parameters of the kirigami structures is build. As a proof of concept demonstration, the constructs for temperature-dependent switching and information encryption is applied. Such reconfigurable kirigami metastructures have significant potential for boosting the fundamental small-scale metastructure research and the design and fabrication of wireless functional devices, wearables, and soft robots at the microscale as well.

14.
Adv Mater ; 33(30): e2100336, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34048125

ABSTRACT

Soft materials that respond to wireless external stimuli are referred to as "smart" materials due to their promising potential in real-world actuation and sensing applications in robotics, microfluidics, and bioengineering. Recent years have witnessed a burst of these stimuli-responsive materials and their preliminary applications. However, their further advancement demands more versatility, configurability, and adaptability to deliver their promised benefits. Here, a dual-stimuli-responsive soft bimorph material with three configurations that enable complex programmable 3D shape-morphing is presented. The material consists of liquid crystal elastomers (LCEs) and magnetic-responsive elastomers (MREs) via facile fabrication that orthogonally integrates their respective stimuli-responsiveness without detrimentally altering their properties. The material offers an unprecedented wide design space and abundant degree-of-freedoms (DoFs) due to the LCE's programmable director field, the MRE's programmable magnetization profile, and diverse geometric configurations. It responds to wireless stimuli of the controlled magnetic field and environmental temperature. Its dual-responsiveness allows the independent control of different DoFs for complex shape-morphing behaviors with anisotropic material properties. A diverse set of in situ reconfigurable shape-morphing and an environment-aware untethered miniature 12-legged robot capable of locomotion and self-gripping are demonstrated. Such material can provide solutions for the development of future soft robotic and other functional devices.

15.
Build Simul ; 14(5): 1543-1552, 2021.
Article in English | MEDLINE | ID: mdl-33686353

ABSTRACT

Airborne transmission is an important mechanism of spread for both viruses and bacteria in hospitals, with nosocomial infections putting a great burden on public health. In this study, we designed and manufactured a bed for pediatric clinic consultation rooms providing air isolation to protect patients and medical personnel from pathogen transmission. The pediatric isolation bed has several primary efficiency filters and a high-efficiency particulate air filter in the bedside unit. The air circulation between inlet and outlet forms negative pressure to remove the patient's exhaled air timeously and effectively. A computational fluid dynamics model was used to calculate the speed of the airflow and the angle of sampler. Following this, we conducted purification experiments using cigarette smoke, Staphylococcus albus (S. albus) and human adenovirus type 5 (HAdV-5) to demonstrate the isolation efficacy. The results showed that the patient's head should be placed as close to the air inlet hood as possible, and an air intake wind speed of 0.86 m/s was effective. The isolation efficacy of the pediatric isolation bed was demonstrated by computational fluid dynamics technology. The isolation efficiency against cigarette smoke exceeded 91.8%, and against S. albus was greater than 99.8%, while the isolation efficiency against HAdV-5 was 100%. The pediatric isolation bed could be used where isolation wards are unavailable, such as in intensive care units and primary clinical settings, to control hospital acquired infections.

16.
Adv Mater ; 33(8): e2006191, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33448077

ABSTRACT

Stimuli-responsive and active materials promise radical advances for many applications. In particular, soft magnetic materials offer precise, fast, and wireless actuation together with versatile functionality, while liquid crystal elastomers (LCEs) are capable of large reversible and programmable shape-morphing with high work densities in response to various environmental stimuli, e.g., temperature, light, and chemical solutions. Integrating the orthogonal stimuli-responsiveness of these two kinds of active materials could potentially enable new functionalities and future applications. Here, magnetic microparticles (MMPs) are embedded into an LCE film to take the respective advantages of both materials without compromising their independent stimuli-responsiveness. This composite material enables reconfigurable magnetic soft miniature machines that can self-adapt to a changing environment. In particular, a miniature soft robot that can autonomously alter its locomotion mode when it moves from air to hot liquid, a vine-like filament that can sense and twine around a support, and a light-switchable magnetic spring are demonstrated. The integration of LCEs and MMPs into monolithic structures introduces a new dimension in the design of soft machines and thus greatly enhances their use in applications in complex environments, especially for miniature soft robots, which are self-adaptable to environmental changes while being remotely controllable.

17.
Adv Mater ; 32(38): e2002753, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32767434

ABSTRACT

The shape-shifting behavior of liquid crystal networks (LCNs) and elastomers (LCEs) is a result of an interplay between their initial geometrical shape and their molecular alignment. For years, reliance on either one-step in situ or two-step film processing techniques has limited the shape-change transformations from 2D to 3D geometries. The combination of various fabrication techniques, alignment methods, and chemical formulations developed in recent years has introduced new opportunities to achieve 3D-to-3D shape-transformations in large scales, albeit the precise control of local molecular alignment in microscale 3D constructs remains a challenge. Here, the voxel-by-voxel encoding of nematic alignment in 3D microstructures of LCNs produced by two-photon polymerization using high-resolution topographical features is demonstrated. 3D LCN microstructures (suspended films, coils, and rings) with designable 2D and 3D director fields with a resolution of 5 µm are achieved. Different shape transformations of LCN microstructures with the same geometry but dissimilar molecular alignments upon actuation are elicited. This strategy offers higher freedom in the shape-change programming of 3D LCN microstructures and expands their applicability in emerging technologies, such as small-scale soft robots and devices and responsive surfaces.

18.
Biosaf Health ; 2(3): 169-176, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32838281

ABSTRACT

The incidences of nosocomial infections (NIs) are increasing throughout the world, especially for those airborne diseases caused by pathogens or air particulates that float in air. In this study, we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient. The air isolation and purification (AIP) desk has a high efficiency particulate air (HEPA) filter on the tope and several primary efficiency filters on the sides for air purification. The air circulating between inlet and outlet forms a wind-curtain between doctor and patient. The Computational Fluid Dynamics (CFD) model was used to calculate the speed of the air flow and the angle of sampler. We tested the air purification function of the AIP desk in rooms sized about 3.6 × 2.8 × 2.8 m (L × W × H) and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus (S. albus)and human adenovirus type 5 (HAdV-5). The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk. Thus, the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.

19.
Proc Natl Acad Sci U S A ; 117(26): 14667-14675, 2020 06 30.
Article in English | MEDLINE | ID: mdl-32532923

ABSTRACT

Many natural materials possess built-in structural variation, endowing them with superior performance. However, it is challenging to realize programmable structural variation in self-assembled synthetic materials since self-assembly processes usually generate uniform and ordered structures. Here, we report the formation of asymmetric microribbons composed of directionally self-assembled two-dimensional nanoflakes in a polymeric matrix during three-dimensional direct-ink printing. The printed ribbons with embedded structural variations show site-specific variance in their mechanical properties. Remarkably, the ribbons can spontaneously transform into ultrastretchable springs with controllable helical architecture upon stimulation. Such springs also exhibit superior nanoscale transport behavior as nanofluidic ionic conductors under even ultralarge tensile strains (>1,000%). Furthermore, to show possible real-world uses of such materials, we demonstrate in vivo neural recording and stimulation using such springs in a bullfrog animal model. Thus, such springs can be used as neural electrodes compatible with soft and dynamic biological tissues.


Subject(s)
Implantable Neurostimulators , Microtechnology/instrumentation , Nanostructures , Printing, Three-Dimensional , Animals , Anura , Elasticity , Graphite/chemistry , Ions/chemistry , Nanostructures/chemistry , Nanostructures/ultrastructure , Neurophysiology/instrumentation , Sciatic Nerve/physiology
20.
Sci Total Environ ; 731: 139234, 2020 Aug 20.
Article in English | MEDLINE | ID: mdl-32413665

ABSTRACT

Endosulfan is a persistent organochlorine pesticide that bioaccumulates in human body through the food chain and thus represents a potential risk to public health. Despite epidemiological studies, the molecular mechanisms underlying the carcinogenic effects of endosulfan in the prostate remain poorly understood. In this study, we investigated the effect of endosulfan on epithelial-mesenchymal transition (EMT) in human prostate cancer PC3 and DU145 cells. Endosulfan induced alterations of EMT biomarkers, reflecting repression of E-cadherin expression and induction of fibronectin, snail2, ZEB2, Twist1 and Vimentin. The expression of Protein-tyrosine Phosphatase 4A3 (PTP4A3) at mRNA and protein levels was upregulated by endosulfan. PTP4A3 inhibitor reversed the changes of EMT biomarkers, PTP4A3 and p-Smad2/Smad2, but did not affect the upregulation of Cleaved-Notch1 and Jagged1 in endosulfan-exposed cells. Endosulfan promoted cell migration and invasion, which were rescued by specific inhibitors for PTP4A3, TGF-ß signaling and Notch signaling, respectively. These findings suggest that endosulfan promoted cell migration and invasion with the induction of EMT through PTP4A3-mediated TGF-ß signaling pathway in prostate cancer cells.


Subject(s)
Endosulfan , Epithelial-Mesenchymal Transition , Prostatic Neoplasms , Cell Line, Tumor , Humans , Male , Neoplasm Proteins , Protein Tyrosine Phosphatases , Signal Transduction , Transforming Growth Factor beta
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