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1.
Cell ; 162(3): 662-74, 2015 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-26189679

RESUMEN

In vivo pharmacology and optogenetics hold tremendous promise for dissection of neural circuits, cellular signaling, and manipulating neurophysiological systems in awake, behaving animals. Existing neural interface technologies, such as metal cannulas connected to external drug supplies for pharmacological infusions and tethered fiber optics for optogenetics, are not ideal for minimally invasive, untethered studies on freely behaving animals. Here, we introduce wireless optofluidic neural probes that combine ultrathin, soft microfluidic drug delivery with cellular-scale inorganic light-emitting diode (µ-ILED) arrays. These probes are orders of magnitude smaller than cannulas and allow wireless, programmed spatiotemporal control of fluid delivery and photostimulation. We demonstrate these devices in freely moving animals to modify gene expression, deliver peptide ligands, and provide concurrent photostimulation with antagonist drug delivery to manipulate mesoaccumbens reward-related behavior. The minimally invasive operation of these probes forecasts utility in other organ systems and species, with potential for broad application in biomedical science, engineering, and medicine.


Asunto(s)
Estimulación Encefálica Profunda/métodos , Optogenética/métodos , Animales , Encéfalo/efectos de los fármacos , Sistemas de Liberación de Medicamentos , Ratones , Sondas Moleculares , Tecnología Inalámbrica
2.
Nature ; 597(7877): 503-510, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34552257

RESUMEN

Large, distributed collections of miniaturized, wireless electronic devices1,2 may form the basis of future systems for environmental monitoring3, population surveillance4, disease management5 and other applications that demand coverage over expansive spatial scales. Aerial schemes to distribute the components for such networks are required, and-inspired by wind-dispersed seeds6-we examined passive structures designed for controlled, unpowered flight across natural environments or city settings. Techniques in mechanically guided assembly of three-dimensional (3D) mesostructures7-9 provide access to miniature, 3D fliers optimized for such purposes, in processes that align with the most sophisticated production techniques for electronic, optoelectronic, microfluidic and microelectromechanical technologies. Here we demonstrate a range of 3D macro-, meso- and microscale fliers produced in this manner, including those that incorporate active electronic and colorimetric payloads. Analytical, computational and experimental studies of the aerodynamics of high-performance structures of this type establish a set of fundamental considerations in bio-inspired design, with a focus on 3D fliers that exhibit controlled rotational kinematics and low terminal velocities. An approach that represents these complex 3D structures as discrete numbers of blades captures the essential physics in simple, analytical scaling forms, validated by computational and experimental results. Battery-free, wireless devices and colorimetric sensors for environmental measurements provide simple examples of a wide spectrum of applications of these unusual concepts.


Asunto(s)
Biomimética , Equipos y Suministros Eléctricos , Miniaturización/instrumentación , Semillas , Viento , Tecnología Inalámbrica/instrumentación , Colorimetría , Monitoreo del Ambiente/instrumentación , Monitoreo del Ambiente/métodos , Fenómenos Mecánicos , Microfluídica , Vigilancia de la Población/métodos , Rotación
3.
Chem Rev ; 123(18): 11137-11189, 2023 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-37676059

RESUMEN

Architected flexible electronic devices with rationally designed 3D geometries have found essential applications in biology, medicine, therapeutics, sensing/imaging, energy, robotics, and daily healthcare. Mechanically-guided 3D assembly methods, exploiting mechanics principles of materials and structures to transform planar electronic devices fabricated using mature semiconductor techniques into 3D architected ones, are promising routes to such architected flexible electronic devices. Here, we comprehensively review mechanically-guided 3D assembly methods for architected flexible electronics. Mainstream methods of mechanically-guided 3D assembly are classified and discussed on the basis of their fundamental deformation modes (i.e., rolling, folding, curving, and buckling). Diverse 3D interconnects and device forms are then summarized, which correspond to the two key components of an architected flexible electronic device. Afterward, structure-induced functionalities are highlighted to provide guidelines for function-driven structural designs of flexible electronics, followed by a collective summary of their resulting applications. Finally, conclusions and outlooks are given, covering routes to achieve extreme deformations and dimensions, inverse design methods, and encapsulation strategies of architected 3D flexible electronics, as well as perspectives on future applications.

4.
Nature ; 572(7770): 511-515, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31435056

RESUMEN

Lithium metal anodes offer high theoretical capacities (3,860 milliampere-hours per gram)1, but rechargeable batteries built with such anodes suffer from dendrite growth and low Coulombic efficiency (the ratio of charge output to charge input), preventing their commercial adoption2,3. The formation of inactive ('dead') lithium- which consists of both (electro)chemically formed Li+ compounds in the solid electrolyte interphase and electrically isolated unreacted metallic Li0 (refs 4,5)-causes capacity loss and safety hazards. Quantitatively distinguishing between Li+ in components of the solid electrolyte interphase and unreacted metallic Li0 has not been possible, owing to the lack of effective diagnostic tools. Optical microscopy6, in situ environmental transmission electron microscopy7,8, X-ray microtomography9 and magnetic resonance imaging10 provide a morphological perspective with little chemical information. Nuclear magnetic resonance11, X-ray photoelectron spectroscopy12 and cryogenic transmission electron microscopy13,14 can distinguish between Li+ in the solid electrolyte interphase and metallic Li0, but their detection ranges are limited to surfaces or local regions. Here we establish the analytical method of titration gas chromatography to quantify the contribution of unreacted metallic Li0 to the total amount of inactive lithium. We identify the unreacted metallic Li0, not the (electro)chemically formed Li+ in the solid electrolyte interphase, as the dominant source of inactive lithium and capacity loss. By coupling the unreacted metallic Li0 content to observations of its local microstructure and nanostructure by cryogenic electron microscopy (both scanning and transmission), we also establish the formation mechanism of inactive lithium in different types of electrolytes and determine the underlying cause of low Coulombic efficiency in plating and stripping (the charge and discharge processes, respectively, in a full cell) of lithium metal anodes. We propose strategies for making lithium plating and stripping more efficient so that lithium metal anodes can be used for next-generation high-energy batteries.

5.
Proc Natl Acad Sci U S A ; 119(49): e2215028119, 2022 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-36442122

RESUMEN

The climbing microrobots have attracted growing attention due to their promising applications in exploration and monitoring of complex, unstructured environments. Soft climbing microrobots based on muscle-like actuators could offer excellent flexibility, adaptability, and mechanical robustness. Despite the remarkable progress in this area, the development of soft microrobots capable of climbing on flat/curved surfaces and transitioning between two different surfaces remains elusive, especially in open spaces. In this study, we address these challenges by developing voltage-driven soft small-scale actuators with customized 3D configurations and active stiffness adjusting. Combination of programmed strain distributions in liquid crystal elastomers (LCEs) and buckling-driven 3D assembly, guided by mechanics modeling, allows for voltage-driven, complex 3D-to-3D shape morphing (bending angle > 200°) at millimeter scales (from 1 to 10 mm), which is unachievable previously. These soft actuators enable development of morphable electroadhesive footpads that can conform to different curved surfaces and stiffness-variable smart joints that allow different locomotion gaits in a single microrobot. By integrating such morphable footpads and smart joints with a deformable body, we report a multigait, soft microrobot (length from 6 to 90 mm, and mass from 0.2 to 3 g) capable of climbing on surfaces with diverse shapes (e.g., flat plane, cylinder, wavy surface, wedge-shaped groove, and sphere) and transitioning between two distinct surfaces. We demonstrate that the microrobot could navigate from one surface to another, recording two corresponding ceilings when carrying an integrated microcamera. The developed soft microrobot can also flip over a barrier, survive extreme compression, and climb bamboo and leaf.


Asunto(s)
Elastómeros , Cristales Líquidos , Membrana Celular , Extremidades , Marcha
6.
Environ Res ; 251(Pt 1): 118573, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38431070

RESUMEN

Anaerobically digested sludge supernatant, characterized by its high ammonia and low biodegradable chemical oxygen demand (COD) content, has raised concerns when returned to mainstream treatment lines due to potential impacts on effluent quality. Addressing this, an aerobic granular sludge (AGS) reactor adopted nitritation/denitritation with external COD addition was utilized and achieved a considerable nitrogen treatment capacity of 4.2 kg N/m3/d, reaching over 90% removal efficiencies for both ammonia and total inorganic nitrogen. This study applied progressively increased nitrogen loading to select for a microbial community that exhibited high nitrogen oxidation and reduction rates, demonstrating peak rates of 0.5 g N/g VSS/d and 3 g N/g VSS/d, respectively. The enrichment of highly efficient microbial community was achieved along with the increased biomass density peaked at 17 g/L MLVSS, with the system retaining small-sized granular sludge at 0.5 mm. The primary ammonia oxidizing bacteria was Nitrosomonas, while Thauera was the dominated denitrifiers. Quantitative polymerase chain reaction analyses reinforced the enhanced nitrogen removal capacity based on the progressively increased abundance of nitrogen cycling functional genes. The high nitrogen treatment capacity, synergistic attributes of high specific microbial activities and the substantial biomass retention, suggest the AGS's efficacy and capacity in ammonia rich wastewater treatment.


Asunto(s)
Amoníaco , Reactores Biológicos , Nitrógeno , Aguas del Alcantarillado , Reactores Biológicos/microbiología , Aguas del Alcantarillado/microbiología , Amoníaco/metabolismo , Nitrógeno/metabolismo , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/microbiología , Aguas Residuales/química , Aerobiosis , Bacterias/metabolismo , Bacterias/genética , Contaminantes Químicos del Agua/metabolismo
7.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33836614

RESUMEN

Structures that significantly and rapidly change their shapes and sizes upon external stimuli have widespread applications in a diversity of areas. The ability to miniaturize these deployable and morphable structures is essential for applications in fields that require high-spatial resolution or minimal invasiveness, such as biomechanics sensing, surgery, and biopsy. Despite intensive studies on the actuation mechanisms and material/structure strategies, it remains challenging to realize deployable and morphable structures in high-performance inorganic materials at small scales (e.g., several millimeters, comparable to the feature size of many biological tissues). The difficulty in integrating actuation materials increases as the size scales down, and many types of actuation forces become too small compared to the structure rigidity at millimeter scales. Here, we present schemes of electromagnetic actuation and design strategies to overcome this challenge, by exploiting the mechanics-guided three-dimensional (3D) assembly to enable integration of current-carrying metallic or magnetic films into millimeter-scale structures that generate controlled Lorentz forces or magnetic forces under an external magnetic field. Tailored designs guided by quantitative modeling and developed scaling laws allow formation of low-rigidity 3D architectures that deform significantly, reversibly, and rapidly by remotely controlled electromagnetic actuation. Reconfigurable mesostructures with multiple stable states can be also achieved, in which distinct 3D configurations are maintained after removal of the magnetic field. Demonstration of a functional device that combines the deep and shallow sensing for simultaneous measurements of thermal conductivities in bilayer films suggests the promising potential of the proposed strategy toward multimodal sensing of biomedical signals.

8.
Surg Innov ; 31(3): 274-285, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38468453

RESUMEN

OBJECTIVE: To study the value of high-quality care in operating room during operation of patients with rectal cancer and the effect of this nursing model on postoperative rehabilitation. METHODS: This study recruited 72 patients with rectal cancer, including 36 in the control group and 36 in the observation group. Patients in the control group received routine care, and those in the observation group received high-quality care in operating room. RESULTS: The anxiety score (5.50 ± .77 vs 10. 08 ± 1.13), stress score (6.97 ± .60 vs 8.61 ± .99), and depression score (4.02 ± .65 vs 5.50 ± .91) in the observation group were less than the control group after treatment (P < .05). The measured values of diastolic blood pressure (73.19 ± 1.96 vs 86.13 ± 2.0), systolic blood pressure (121.08 ± 1.62 vs 130.63 ± 2.84), heart rate (73.05 ± 1.63 vs 87.11 ± 2.91) and adrenaline E(E) (58.40 ± 3.02 vs 61.42 ± 3.86) in the observation group were less than the control group after treatment (P < .05). The cooperation degree (94.44 vs 75.00) in the observation group was greater than the control group, but the operation time (308.47 ± 9.92 vs 339.47 ± 12.70), postoperative intestinal function recovery time (16.30 ± 1.14 vs 30.94 ± 2.10) and length of stay (10.47 ± 1.85 vs 13.33 ± 1.95) were all shorter than the control group (P < .05). The nasopharyngeal temperature in the observation group was greater than the control group at 30 minutes during operation (36.16 ± .50 vs 35.19 ± .40) and after operation, and fear score (2.22 ± .42 vs 3.63 ± .72) was less than the control group (P < .05). CONCLUSION: The application of high-quality care in the operating room during rectal cancer surgery has a significantly good clinical outcome.


Asunto(s)
Neoplasias del Recto , Humanos , Neoplasias del Recto/cirugía , Femenino , Masculino , Persona de Mediana Edad , Quirófanos/normas , Anciano , Adulto , Complicaciones Posoperatorias , Cuidados Posoperatorios/normas
9.
J Neurosci ; 42(16): 3305-3315, 2022 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-35256530

RESUMEN

The presynaptic action potential (AP) is required to drive calcium influx into nerve terminals, resulting in neurotransmitter release. Accordingly, the AP waveform is crucial in determining the timing and strength of synaptic transmission. The calyx of Held nerve terminals of rats of either sex showed minimum changes in AP waveform during high-frequency AP firing. We found that the stability of the calyceal AP waveform requires KCNQ (KV7) K+ channel activation during high-frequency spiking activity. High-frequency presynaptic spikes gradually led to accumulation of KCNQ channels in open states which kept interspike membrane potential sufficiently negative to maintain Na+ channel availability. Blocking KCNQ channels during stimulus trains led to inactivation of presynaptic Na+, and to a lesser extent KV1 channels, thereby reducing the AP amplitude and broadening AP duration. Moreover, blocking KCNQ channels disrupted the stable calcium influx and glutamate release required for reliable synaptic transmission at high frequency. Thus, while KCNQ channels are generally thought to prevent hyperactivity of neurons, we find that in axon terminals these channels function to facilitate reliable high-frequency synaptic signaling needed for sensory information processing.SIGNIFICANCE STATEMENT The presynaptic spike results in calcium influx required for neurotransmitter release. For this reason, the spike waveform is crucial in determining the timing and strength of synaptic transmission. Auditory information is encoded by spikes phase locked to sound frequency at high rates. The calyx of Held nerve terminals in the auditory brainstem show minimum changes in spike waveform during high-frequency spike firing. We found that activation of KCNQ K+ channel builds up during high-frequency firing and its activation helps to maintain a stable spike waveform and reliable synaptic transmission. While KCNQ channels are generally thought to prevent hyperexcitability of neurons, we find that in axon terminals these channels function to facilitate high-frequency synaptic signaling during auditory information processing.


Asunto(s)
Calcio , Transmisión Sináptica , Potenciales de Acción/fisiología , Animales , Neurotransmisores , Terminales Presinápticos/fisiología , Ratas , Sodio , Transmisión Sináptica/fisiología
10.
Neuroimage ; 266: 119817, 2023 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-36535320

RESUMEN

Heartbeat-evoked responses (HERs) can interact with external stimuli and play a crucial role in shaping perception, self-related processes, and emotional processes. On the one hand, the external stimulus could modulate HERs. On the other hand, the HERs could affect cognitive processing of the external stimulus. Whether the same neural mechanism underlies these two processes, however, remains unclear. Here, we investigated this interactive mechanism by measuring HERs using magnetoencephalography (MEG) and two name perception tasks. Specifically, we tested (1) how hearing a subject's own name (SON) modulates HERs and (2) how the judgment of an SON is biased by prestimulus HERs. The results showed a dual interaction between HERs and SON. In particular, SON can modulate HERs for heartbeats occurring from 200 to 1200 ms after SON presentation. In addition, prestimulus HERs can bias the SON judgment when a stimulus is presented. Importantly, MEG activities from these two types of interactions differed in spatial and temporal patterns, suggesting that they may be associated with distinct neural pathways. These findings extend our understanding of brain-heart interactions.


Asunto(s)
Encéfalo , Magnetoencefalografía , Humanos , Frecuencia Cardíaca/fisiología , Encéfalo/fisiología , Emociones , Juicio
11.
J Nanobiotechnology ; 21(1): 129, 2023 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-37055835

RESUMEN

BACKGROUND: Excessive oxidative stress at the wound sites always leads to a prolonged healing and even causes chronic inflammatory wounds. Therefore, antioxidative dressings with multiple features are desired to improve wound healing performance. Herein, we fabricated a ROS-scavenging hybrid hydrogel by incorporating mussel-inspired fullerene nanocomposites (C60@PDA) into gelatin methacryloyl (GelMA) hydrogel. RESULTS: The developed C60@PDA/GelMA hydrogel showed a sustainable free radical scavenging ability, and eliminated ROS to protect cells against external oxidative stress damage. Besides, the hydrogel presented favorable cytocompatibility, hemocompatibility, and antibacterial ability in vitro. Furthermore, in a mouse full-thickness wound defect model, the in situ forming hybrid hydrogel accelerated wound closure by 38.5% and 42.9% on day 3 and day 7 over the control. Histological results demonstrated that hybrid hydrogels effectively enhanced wound healing on re-epithelialization, collagen deposition and angiogenesis. CONCLUSION: Collectively, the C60@PDA/GelMA hydrogel could be a promising dressing for promoting cutaneous wound repair.


Asunto(s)
Fulerenos , Nanocompuestos , Animales , Ratones , Hidrogeles , Cicatrización de Heridas , Fulerenos/farmacología , Especies Reactivas de Oxígeno , Modelos Animales de Enfermedad , Nanocompuestos/uso terapéutico , Antibacterianos/farmacología
12.
J Nanobiotechnology ; 21(1): 435, 2023 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-37981675

RESUMEN

BACKGROUND: Bacterial infection, complex wound microenvironment and persistent inflammation cause delayed wound healing and scar formation, thereby disrupting the normal function and appearance of skin tissue, which is one of the most problematic clinical issues. Although Ag NPs have a strong antibacterial effect, they tend to oxidize and form aggregates in aqueous solution, which reduces their antibacterial efficacy and increases their toxicity to tissues and organs. Current research on scar treatment is limited and mainly relies on growth factors and drugs to reduce inflammation and scar tissue formation. Therefore, there is a need to develop methods that effectively combine drug delivery, antimicrobial and anti-inflammatory agents to modulate the wound microenvironment, promote wound healing, and prevent skin scarring. RESULTS: Herein, we developed an innovative Ag nanocomposite hydrogel (Ag NCH) by incorporating Ag nanoparticles (Ag NPs) into a matrix formed by linking catechol-modified hyaluronic acid (HA-CA) with 4-arm PEG-SH. The Ag NPs serve dual functions: they act as reservoirs for releasing Ag/Ag+ at the wound site to combat bacterial infections, and they also function as cross-linkers to ensure the sustained release of basic fibroblast growth factor (bFGF). The potent antibacterial effect of the Ag NPs embedded in the hydrogel against S.aureus was validated through comprehensive in vitro and in vivo analyses. The microstructural analysis of the hydrogels and the in vitro release studies confirmed that the Ag NCH possesses smaller pore sizes and facilitates a slower, more sustained release of bFGF. When applied to acute and infected wound sites, the Ag NCH demonstrated remarkable capabilities in reshaping the immune and regenerative microenvironment. It induced a shift from M1 to M2 macrophage polarization, down-regulated the expression of pro-inflammatory factors such as IL-6 and TNF-α, and up-regulated the expression of anti-inflammatory IL-10. Furthermore, the Ag NCH played a crucial role in regulating collagen deposition and alignment, promoting the formation of mature blood vessels, and significantly enhancing tissue reconstruction and scarless wound healing processes. CONCLUSIONS: We think the designed Ag NCH can provide a promising therapeutic strategy for clinical applications in scarless wound healing and antibacterial therapy.


Asunto(s)
Cicatriz , Nanopartículas del Metal , Humanos , Antibacterianos/farmacología , Preparaciones de Acción Retardada , Inflamación , Nanogeles , Plata/farmacología , Cicatrización de Heridas , Nanocompuestos
13.
Molecules ; 28(2)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36677664

RESUMEN

Pyrite has been used in photo-Fenton reactions for the degradation of pollutants, but the application of photo-Fenton processes with extra H2O2 in real water/wastewater treatment has still been limited by the economic cost of H2O2 and artificial light sources. Herein, citric acid (CA) and simulated/natural sunlight are used to develop a pyrite-based photo-Fenton system (pyrite-CA-light) in situ generating H2O2 through the enhanced activation of molecular oxygen. The degradation of pharmaceuticals and personal care products (PPCPs), especially acetaminophen (APAP) as the main target pollutant, in the pyrite-CA-light system was investigated. The effects of influencing factors such as various organic acids, APAP concentration, pH, pyrite dosage, CA concentration and co-existing anions (HCO3-, Cl-, NO3-, SO42- and H2PO4-) were examined. At a pyrite dosage of 0.1 g L-1, CA concentration of 0.6 mM and an initial pH of 6.0, the degradation efficiency of APAP (30 µM) was 99.1% within 30 min under the irradiation of xenon lamp (70 W, λ ≥ 350 nm). Almost the same high efficiency of APAP degradation (93.9%) in the system was achieved under natural sunlight irradiation (ca. 650 W m-2). The scavenging experiments revealed that the dominant active species for degrading APAP was hydroxyl radical (HO•). Moreover, a quantitative structural-activity relationship (QSAR) model for pseudo-first-order rate constants (kobs) was established with a high significance (R2 = 0.932, p = 0.001) by using three descriptors: octanol-water partition coefficient (logKow), dissociation constant (pKa) and highest occupied molecular orbital (HOMO). This work provides an innovative strategy of the photo-Fenton process for the degradation of PPCPs using natural minerals and ordinary carboxylic acid under sunlight.

14.
Small ; 18(17): e2107879, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35307953

RESUMEN

Island-bridge architectures represent a widely used structural design in stretchable inorganic electronics, where deformable interconnects that form the bridge provide system stretchability, and functional components that reside on the islands undergo negligible deformations. These device systems usually experience a common strain concentration phenomenon, i.e., "island effect", because of the modulus mismatch between the soft elastomer substrate and its on-top rigid components. Such an island effect can significantly raise the surrounding local strain, therefore increasing the risk of material failure for the interconnects in the vicinity of the islands. In this work, a systematic study of such an island effect through combined theoretical analysis, numerical simulations and experimental measurements is presented. To relieve the island effect, a buffer layer strategy is proposed as a generic route to enhanced stretchabilities of deformable interconnects. Both experimental and numerical results illustrate the applicability of this strategy to 2D serpentine and 3D helical interconnects, as evidenced by the increased stretchabilities (e.g., by 1.5 times with a simple buffer layer, and 2 times with a ring buffer layer, both for serpentine interconnects). The application of the patterned buffer layer strategy in a stretchable light emitting diodes system suggests promising potentials for uses in other functional device systems.

15.
Biol Reprod ; 107(6): 1452-1463, 2022 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-36136742

RESUMEN

After fertilization, the zygote undergoes cell division. Up to the 8-cell stage, the blastomeres of mouse preimplantation embryos are morphologically identical. The first cell differentiation starts in the morula leading to the formation of trophectoderm cells and inner cell mass cells of the blastocyst. The regulation of the differentiation event and the formation of blastocysts are not fully known. Lethal-7 (let-7) is a family of evolutionarily conserved microRNAs. Here, we showed that the expression of let-7a and let-7g decreased drastically from the 1-cell stage to the 2-cell stage, remained low up to the 8-cell stage and slightly increased after the morula stage of mouse embryos. The expression of let-7 in the inner cell mass was higher than that in the trophectoderm. Forced expression of let-7a in embryos at the 1-cell and 4-cell stage inhibited blastocyst formation and downregulated the expression of CDX2 but maintained that of OCT4 in the trophectoderm. Forced expression of other let-7 isoforms exhibited similar inhibitory action on blastulation. On the other hand, inhibition of let-7a at the 4-cell stage and the 8-cell stage enhanced blastocyst formation. Co-injection of green fluorescent protein (GFP) mRNA (lineage tracer) with either precursor of let-7a (pre-let-7a) or scramble control into one blastomere of 2-cell embryos showed that ~75% of the resulting blastocysts possessed GFP+ cells in their inner cell mass only. The biased development towards the inner cell mass with forced expression of let-7 was reproduced in 2-cell chimeric embryos consisting of one wildtype blastomere and one GFP mRNA-injected blastomere from another 2-cell embryo carrying a doxycycline-inducible let-7g gene. Bioinformatics analysis indicated that Tead4 was a potential target of let-7. Let-7 bound to the 3'UTR of Tead4 and let-7 forced expression downregulated the expression of Tead4 in mouse blastocysts. Co-injection of Tead4 mRNA partially nullified the modulatory roles of let-7a in the inner cell mass cell fate. In conclusion, a high level of let-7 at the 2-cell stage favored the formation of the inner cell mass, whereas a low level of let-7 at the 4-cell to 8-cell stage enhanced blastocyst formation. Tead4 mediated the action of let-7 on the inner cell mass cell-fate determination.


Asunto(s)
Blastocisto , Regulación del Desarrollo de la Expresión Génica , MicroARNs , Animales , Ratones , Blastocisto/citología , Diferenciación Celular/genética , Desarrollo Embrionario/genética , MicroARNs/genética , ARN Mensajero/genética , Factores de Transcripción/genética
16.
Opt Express ; 30(13): 24084-24102, 2022 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-36225077

RESUMEN

With the presence of complex background noise, parasitic light, and dust attachment, it is still a challenging issue to perform high-precision laser-induced damage change detection of optical elements in the captured optical images. For resolving this problem, this paper presents an end-to-end damage change detection model based on siamese network and multi-layer perceptrons (SiamMLP). Firstly, representative features of bi-temporal damage images are efficiently extracted by the cascaded multi-layer perceptron modules in the siamese network. After that, the extracted features are concatenated and then classified into changed and unchanged classes. Due to its concise architecture and strong feature representation ability, the proposed method obtains excellent damage change detection results efficiently and effectively. To address the unbalanced distribution of hard and easy samples, a novel metric called hard metric is introduced in this paper for quantitatively evaluating the classification difficulty degree of the samples. The hard metric assigns a classification difficulty for each individual sample to precisely adjust the loss assigned to the sample. In the training stage, a novel hard loss is presented to train the proposed model. Cooperating with the hard metric, the hard loss can up-weight the loss of hard samples and down-weight the loss of easy samples, which results in a more powerful online hard sample mining ability of the proposed model. The experimental results on two real datasets validate the effectiveness and superiority of the proposed method.

17.
Glob Chang Biol ; 28(14): 4423-4438, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35447006

RESUMEN

Theory and experiments support that plant invasions largely impact aboveground biodiversity and function. Yet, much less is known on the influence of plant invasions on the structure and function of the soil microbiome of coastal wetlands, one of the largest major reservoirs of biodiversity and carbon on Earth. We studied the continental-scale invasion of Spartina alterniflora across 2451 km of Chinese coastlines as our model-system and found that S. alterniflora invasion can largely influence the soil microbiome (across six depths from 0 to 100 cm), compared with the most common microhabitat found before invasion (mudflats, Mud). In detail, S. alterniflora invasion was not only positively associated with bacterial richness but also resulted in important biotic homogenization of bacterial communities, suggesting that plant invasion can lead to important continental scale trade-offs in the soil microbiome. We found that plant invasion changed the community composition of soil bacterial communities across the soil profile. Moreover, the bacterial communities associated with S. alterniflora invasions where less responsive to climatic changes than those in native Mud microhabitats, suggesting that these new microbial communities might become more dominant under climate change. Plant invasion also resulted in important reductions in the complexity and stability of microbial networks, decoupling the associations between microbes and carbon pools. Taken together, our results indicated that plant invasions can largely influence the microbiome of coastal wetlands at the scale of China, representing the first continental-scale example on how plant invasions can reshuffle the soil microbiome, with consequences for the myriad of functions that they support.


Asunto(s)
Microbiota , Suelo , Bacterias , Carbono/análisis , China , Especies Introducidas , Plantas , Poaceae , Suelo/química , Humedales
18.
J Org Chem ; 87(9): 6426-6431, 2022 05 06.
Artículo en Inglés | MEDLINE | ID: mdl-35439001

RESUMEN

An intramolecular formal [3+2] cycloaddition of activated aziridines and epoxides with electron-deficient alkene has been developed for the general and efficient construction of bridged aza- and oxa-[n.2.1] (n = 3 or 4) skeletons. This strategy can be efficiently promoted by lithium iodide. To demonstrate its potential, the intramolecular formal [3+2] cycloaddition was used to access the important intermediate of homoepiboxidine.


Asunto(s)
Alquenos , Aziridinas , Catálisis , Reacción de Cicloadición , Electrones , Compuestos Epoxi , Esqueleto
19.
Paediatr Perinat Epidemiol ; 36(3): 390-398, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34431114

RESUMEN

BACKGROUND: For initial respiratory management, continuous positive airway pressure (CPAP) is increasingly used for preterm infants, especially for gestational age less than 32 weeks. However, neonatologists are concerned about the potential risks of CPAP support failure. OBJECTIVES: To examine the association between different initial respiratory support modalities and the outcomes of preterm infants at <32 weeks of gestation across multiple neonatal intensive care units (NICU) in China. METHODS: This study was carried out over a period of 12 months in 2018. Unadjusted relative risks (RR) for demographic and clinical characteristics were calculated for CPAP failure and CPAP success in the total cohort using log-linear model based on generalised estimating equations for clustered observations. RESULTS: Among 1560 preterm infants delivered at <32 weeks, the incidence of CPAP failure was 10.3%. After adjustment for demographic and clinical factors, the relative risk of mortality (RR 7.54, 95% CI 5.56, 10.44), pneumothorax (RR 9.85, 95% CI 2.89, 61.53), pulmonary haemorrhage (RR 7.78, 95% CI 4.51, 14.64) and BPD (RR 3.65, 95% CI 3.65, 4.51) were considerably higher for infants in the CPAP failure group than those in the CPAP-S group. However, the risk of poor outcomes in CPAP failure infants was similar to that of those in the initial mechanical ventilation (MV) group. CONCLUSIONS: Continuous positive airway pressure failure was associated with an increased risk of mortality and major morbidities, including BPD, pulmonary haemorrhage and pneumothorax, and was comparable to the risk associated with initial MV.


Asunto(s)
Neumotórax , Síndrome de Dificultad Respiratoria del Recién Nacido , Presión de las Vías Aéreas Positiva Contínua/efectos adversos , Femenino , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Neumotórax/etiología , Embarazo , Síndrome de Dificultad Respiratoria del Recién Nacido/complicaciones , Síndrome de Dificultad Respiratoria del Recién Nacido/epidemiología , Síndrome de Dificultad Respiratoria del Recién Nacido/terapia , Estudios Retrospectivos
20.
BMC Musculoskelet Disord ; 23(1): 833, 2022 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-36057596

RESUMEN

PURPOSE: To explore the correlation between intervertebral disc degeneration (IDD) and bone mineral density (BMD) difference between adjacent vertebrae. METHODS: A retrospective analysis of 114 postmenopausal women who were treated in our hospital from January 2021 to December 2021. The degree of lumbar(L)1-5 IDD was scored according to an 8-grade scoring system. The lumbar vertebrae BMD was detected, and the BMD difference was calculated. The subjects were grouped according to age and whether the disc was severe IDD. Data were collected for statistical analysis. RESULTS: The prevalence of osteoporosis in the 51-60-year-old group was lower than that in the other groups, while the prevalence of modic changes in the 71-80-year-old group was higher than that in the 51-70-year-old group (P < 0.05). At the L1/2 level, the prevalence of severe IDD in the 81-90y group was higher than that in the 51-70y group (P < 0.05). At the L2/3 level, the prevalence of severe IDD in the 71-90y group was higher than that in the 51-60y group, and the prevalence of severe IDD in the 71-80y group was higher than that in the 61-70y group (P < 0.05). The L2/3 disc score was positively correlated with the L3-L2 BMD difference (P < 0.05). At the level of L1-2, the BMD difference in the non-severe IDD group was smaller than that in the severe IDD group (P < 0.05). CONCLUSION: For postmenopausal women, an increase in BMD difference is correlated with IDD. Osteoporosis is more common in people over 60 years old, and the possibility of modic change in 71-80y is higher than in other age groups. The incidence of severe IDD also increases with aging, especially for the L1/2 and L2/3 discs.


Asunto(s)
Degeneración del Disco Intervertebral , Disco Intervertebral , Osteoporosis , Anciano , Anciano de 80 o más Años , Densidad Ósea , Femenino , Humanos , Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/epidemiología , Vértebras Lumbares/diagnóstico por imagen , Imagen por Resonancia Magnética , Persona de Mediana Edad , Posmenopausia , Estudios Retrospectivos , Radioisótopos de Itrio
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