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1.
Psychophysiology ; 61(11): e14652, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38992865

RESUMO

Our actions shape our everyday experience: what we experience, how we perceive, and remember it are deeply affected by how we interact with the world. Performing an action to deliver a stimulus engages neurophysiological processes which are reflected in the modulation of sensory and pupil responses. We hypothesized that these processes shape memory encoding, parsing the experience by grouping self- and externally generated stimuli into differentiated events. Participants encoded sound sequences, in which either the first or last few sounds were self-generated and the rest externally generated. We tested recall of the sequential order of sounds that had originated from the same (within event) or different sources (across events). Memory performance was not higher for within-event sounds, suggesting that actions did not structure the memory representation. However, during encoding, we observed the expected electrophysiological response attenuation for self-generated sounds, together with increased pupil dilation triggered by actions. Moreover, at the boundary between events, physiological responses to the first sound from the new source were influenced by the direction of the source switch. Our results suggest that introducing actions creates a stronger contextual shift than removing them, even though actions do not directly contribute to memory performance. This study contributes to our understanding of how interacting with sensory input shapes experiences by exploring the relationships between action effects on sensory responses, pupil dilation, and memory encoding. Importantly, it challenges the notion of a meaningful contribution from low-level neurophysiological mechanisms associated with action execution in the modulation of the self-generation effect.


Assuntos
Percepção Auditiva , Pupila , Humanos , Pupila/fisiologia , Feminino , Masculino , Adulto Jovem , Percepção Auditiva/fisiologia , Adulto , Rememoração Mental/fisiologia , Memória/fisiologia , Eletroencefalografia
2.
Exp Brain Res ; 242(1): 47-57, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37947851

RESUMO

Omitted stimulus potentials (OSPs) occur when a sensory stimulus is unexpectedly omitted. They are thought to reflect predictions about upcoming sensory events. The present study examined how OSPs differ across the sensory modalities of predicted stimuli. Twenty-nine university students were asked to press a mouse button at a regular interval of 1-2 s, which was immediately followed by either a visual or auditory stimulus in different blocks. The stimuli were sometimes omitted (p = 0.2), to which event-related potentials (ERPs) were recorded. The results showed that stimulus omissions in both modalities elicited ERP waveforms consisting of three components, oN1, oN2, and oP3. The peak latencies of these components were shorter in the auditory modality than in the visual modality. The amplitudes of OSPs were larger when participants were told that the omission indicated their poor performance (i.e., they pressed a button at an irregular interval) than when it was irrelevant to their performance. These findings suggest that OSPs occur from around 100 ms in a modality-specific manner and increase in amplitude depending on the task relevance of stimulus omissions.


Assuntos
Eletroencefalografia , Potenciais Evocados , Humanos , Estimulação Acústica , Potenciais Evocados Auditivos , Estimulação Luminosa/métodos , Tempo de Reação
3.
Cogn Emot ; 38(1): 120-130, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37882206

RESUMO

Deficits in the ability to read the emotions of others have been demonstrated in mental disorders, such as dissociation and schizophrenia, which involve a distorted sense of self. This study examined whether weakened self-referential source memory, being unable to remember whether a piece of information has been processed with reference to oneself, is linked to ineffective emotion recognition. In two samples from a college and community, we quantified the participants' ability to remember the self-generated versus non-self-generated origins of sentences they had previously read or partially generated. We also measured their ability to read others' emotions accurately when viewing photos of people in affect-charged situations. Multinomial processing tree modelling was applied to obtain a measure of self-referential source memory that was not biased by non-mnemonic factors. Our first experiment with college participants revealed a positive correlation between correctly remembering the origins of sentences and accurately recognising the emotions of others. This correlation was successfully replicated in the second experiment with community participants. The current study offers evidence of a link between self-referential source memory and emotion recognition.


Assuntos
Rememoração Mental , Reconhecimento Psicológico , Humanos , Emoções , Autoimagem
4.
J Exp Child Psychol ; 153: 110-125, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27728784

RESUMO

For children to build a knowledge base, they must integrate and extend knowledge acquired across separate episodes of new learning. Children's performance was assessed in a task requiring them to self-generate new factual knowledge from the integration of novel facts presented through separate lessons in the classroom. Whether self-generation performance predicted academic outcomes in reading comprehension and mathematics was also examined. The 278 participating children were in kindergarten through Grade 3 (mean age=7.7years, range=5.5-10.3). Children self-generated new factual knowledge through integration in the classroom; age-related increases were observed. Self-generation performance predicted both reading comprehension and mathematics academic outcomes, even when controlling for caregiver education.


Assuntos
Desenvolvimento Infantil , Compreensão , Aprendizagem , Instituições Acadêmicas , Pensamento , Logro , Fatores Etários , Criança , Feminino , Humanos , Masculino , Matemática , Leitura
5.
Neuropsychol Rehabil ; 27(1): 60-79, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26095199

RESUMO

Errorless learning has demonstrated efficacy in the treatment of memory impairment in adults and older adults with acquired brain injury. In the same population, use of elaborative encoding through supported self-generation in errorless paradigms has been shown to further enhance memory performance. However, the evidence base relevant to application of both standard and self-generation forms of errorless learning in children is far weaker. We address this limitation in the present study to examine recall performance in children with brain injury (n = 16) who were taught novel age-appropriate science and social science facts through the medium of Skype. All participants were taught these facts under conditions of standard errorless learning, errorless learning with self-generation, and trial-and-error learning after which memory was tested at 5-minute, 30-minute, 1-hour and 24-hour delays. Analysis revealed no main effect of time, with participants retaining most information acquired over the 24-hour testing period, but a significant effect of condition. Notably, self-generation proved more effective than both standard errorless and trial-and-error learning. Further analysis of the data revealed that severity of attentional impairment was less detrimental to recall performance under errorless conditions. This study extends the literature to provide further evidence of the value of errorless learning methods in children with ABI and the first demonstration of the effectiveness of self-generation when delivered via the Internet.


Assuntos
Lesões Encefálicas/reabilitação , Aprendizagem , Transtornos da Memória/reabilitação , Reabilitação Neurológica , Telecomunicações , Adolescente , Lesões Encefálicas/psicologia , Lesões Encefálicas Traumáticas/psicologia , Lesões Encefálicas Traumáticas/reabilitação , Neoplasias Encefálicas/psicologia , Neoplasias Encefálicas/reabilitação , Hemorragia Cerebral/psicologia , Hemorragia Cerebral/reabilitação , Infarto Cerebral/psicologia , Infarto Cerebral/reabilitação , Criança , Encefalite/psicologia , Encefalite/reabilitação , Feminino , Humanos , Hidrocefalia/psicologia , Hidrocefalia/reabilitação , Masculino , Transtornos da Memória/psicologia , Rememoração Mental , Leucemia-Linfoma Linfoblástico de Células Precursoras/psicologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/reabilitação
6.
Aging Clin Exp Res ; 28(5): 935-41, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26620673

RESUMO

BACKGROUND AND AIMS: There is a substantial body of literature showing memory enhancement for self-generated information in normal aging. The present paper investigated this outcome for destination memory or memory for outputted information. METHODS: In Experiment 1, younger adults and older adults had to place (self-generated actions) and observe an experimenter placing (experiment-generated actions) items into two different destinations (i.e., a black circular box and a white square box). On a subsequent recognition task, the participants had to decide into which box each item had originally been placed. These procedures showed better destination memory for self- than experimenter-generated actions. In Experiment 2, destination and source memory were assessed for self-generated actions. Younger adults and older adults had to place items into the two boxes (self-generated actions), take items out of the boxes (self-generated actions), and observe an experimenter taking items out of the boxes (experiment-generated actions). On a subsequent recognition task, they had to decide into which box (destination memory)/from which box (source memory) each item had originally been placed/taken. RESULTS: For both populations, source memory was better than destination memory for self-generated actions, and both were better than source memory for experimenter-generated actions. DISCUSSIONS AND CONCLUSIONS: Taken together, these findings highlight the beneficial effect of self-generation on destination memory in older adults.


Assuntos
Envelhecimento/fisiologia , Memória/fisiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
Front Comput Neurosci ; 18: 1421458, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39161702

RESUMO

Introduction: Behaviors often involve a sequence of events, and learning and reproducing it is essential for sequential memory. Brain loop structures refer to loop-shaped inter-regional connection structures in the brain such as cortico-basal ganglia-thalamic and cortico-cerebellar loops. They are thought to play a crucial role in supporting sequential memory, but it is unclear what properties of the loop structure are important and why. Methods: In this study, we investigated conditions necessary for the learning of sequential memory in brain loop structures via computational modeling. We assumed that sequential memory emerges due to delayed information transmission in loop structures and presented a basic neural activity model and validated our theoretical considerations with spiking neural network simulations. Results: Based on this model, we described the factors for the learning of sequential memory: first, the information transmission delay should decrease as the size of the loop structure increases; and second, the likelihood of the learning of sequential memory increases as the size of the loop structure increases and soon saturates. Combining these factors, we showed that moderate-sized brain loop structures are advantageous for the learning of sequential memory due to the physiological restrictions of information transmission delay. Discussion: Our results will help us better understand the relationship between sequential memory and brain loop structures.

8.
Psychophysiology ; 60(10): e14337, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37209002

RESUMO

Active engagement improves learning and memory, and self- versus externally generated stimuli are processed differently: perceptual intensity and neural responses are attenuated. Whether the attenuation is linked to memory formation remains unclear. This study investigates whether active oculomotor control over auditory stimuli-controlling for movement and stimulus predictability-benefits associative learning, and studies the underlying neural mechanisms. Using EEG and eye tracking we explored the impact of control during learning on the processing and memory recall of arbitrary oculomotor-auditory associations. Participants (N = 23) learned associations through active exploration or passive observation, using a gaze-controlled interface to generate sounds. Our results show faster learning progress in the active condition. ERPs time-locked to the onset of sound stimuli showed that learning progress was linked to an attenuation of the P3a component. The detection of matching movement-sound pairs triggered a target-matching P3b. There was no general modulation of ERPs through active learning. However, we found continuous variation in the strength of the memory benefit across participants: some benefited more strongly from active control during learning than others. This was paralleled in the strength of the N1 attenuation effect for self-generated stimuli, which was correlated with memory gain in active learning. Our results show that control helps learning and memory and modulates sensory responses. Individual differences during sensory processing predict the strength of the memory benefit. Taken together, these results help to disentangle the effects of agency, unspecific motor-based neuromodulation, and predictability on ERP components and establish a link between self-generation effects and active learning memory gain.


Assuntos
Potenciais Evocados , Memória , Humanos , Potenciais Evocados/fisiologia , Estimulação Acústica/métodos , Som , Sensação , Percepção Auditiva/fisiologia , Eletroencefalografia , Potenciais Evocados Auditivos/fisiologia
9.
Psychophysiology ; 60(1): e14156, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35918912

RESUMO

Actions modulate sensory processing by attenuating responses to self- compared to externally generated inputs, which is traditionally attributed to stimulus-specific motor predictions. Yet, suppression has been also found for stimuli merely coinciding with actions, pointing to unspecific processes that may be driven by neuromodulatory systems. Meanwhile, the differential processing for self-generated stimuli raises the possibility of producing effects also on memory for these stimuli; however, evidence remains mixed as to the direction of the effects. Here, we assessed the effects of actions on sensory processing and memory encoding of concomitant, but unpredictable sounds, using a combination of self-generation and memory recognition task concurrently with EEG and pupil recordings. At encoding, subjects performed button presses that half of the time generated a sound (motor-auditory; MA) and listened to passively presented sounds (auditory-only; A). At retrieval, two sounds were presented and participants had to respond which one was present before. We measured memory bias and memory performance by having sequences where either both or only one of the test sounds were presented at encoding, respectively. Results showed worse memory performance - but no differences in memory bias -, attenuated responses, and larger pupil diameter for MA compared to A sounds. Critically, the larger the sensory attenuation and pupil diameter, the worse the memory performance for MA sounds. Nevertheless, sensory attenuation did not correlate with pupil dilation. Collectively, our findings suggest that sensory attenuation and neuromodulatory processes coexist during actions, and both relate to disrupted memory for concurrent, albeit unpredictable sounds.


Assuntos
Eletroencefalografia , Potenciais Evocados Auditivos , Humanos , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica , Percepção Auditiva/fisiologia , Som
10.
J Orthop Surg Res ; 18(1): 53, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36653843

RESUMO

BACKGROUND: Guided bone self-generation with periosteum-preserved has successfully regenerated mandibular, temporomandibular and interphalangeal joint. The aim of this study was to investigate the dynamic changes of gene expression of periosteum which was involved in the guided bone self-generation. METHODS: Rib defects of critical size were created in mature swine with periosteum-preserved. The periosteum was sutured into a sealed sheath that closed the bone defect. The periosteum of trauma and control sites were harvested at postoperative 9 time points, and total RNA was extracted. Microarray analysis was conducted to identify the differences in the transcriptome of different time points between two groups. RESULTS: The differentially expressed genes (DEGs) between control and trauma group were different at postoperative different time points. The dynamic changes of the number of DEGs fluctuated a lot. There were 3 volatility peaks, and we chose 3 time points of DEG number peak (1 week, 5 weeks and 6 months) to study the functions of DEGs. Oxidoreductase activity, oxidation-reduction process and mitochondrion are the most enriched terms of Go analysis. The major signaling pathways of DEGs enrichment include oxidative phosphorylation, PI3K-Akt signaling pathway, osteoclast differentiation pathway and Wnt signaling. CONCLUSIONS: The oxidoreductase reaction was activated during this bone regeneration process. The oxidative phosphorylation, PI3K-Akt signaling pathway, osteoclast differentiation pathway and Wnt signaling may play important roles in the guided bone self-generation with periosteum-preserved. This study can provide a reference for how to improve the application of this concept of bone regeneration.


Assuntos
Periósteo , Fosfatidilinositol 3-Quinases , Suínos , Animais , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regeneração Óssea/genética , Via de Sinalização Wnt/genética
11.
Front Hum Neurosci ; 17: 1124784, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36923585

RESUMO

When memorizing a list of words, those that are read aloud are remembered better than those read silently, a phenomenon known as the production effect. There have been several attempts to understand the production effect, however, actions alone have not been examined as possible contributors. Stimuli that coincide with our own actions are processed differently compared to stimuli presented passively to us. These sensory response modulations may have an impact on how action-revolving inputs are stored in memory. In this study, we investigated whether actions could impact auditory memory. Participants listened to sounds presented either during or in between their actions. We measured electrophysiological responses to the sounds and tested participants' memory of them. Results showed attenuation of sensory responses for action-coinciding sounds. However, we did not find a significant effect on memory performance. The absence of significant behavioral findings suggests that the production effect may be not dependent on the effects of actions per se. We conclude that action alone is not sufficient to improve memory performance, and thus elicit a production effect.

12.
Front Robot AI ; 9: 788212, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35480088

RESUMO

Strategic management and production of internal energy in autonomous robots is becoming a research topic with growing importance, especially for platforms that target long-endurance missions, with long-range and duration. It is fundamental for autonomous vehicles to have energy self-generation capability to improve energy autonomy, especially in situations where refueling is not viable, such as an autonomous sailboat in ocean traversing. Hence, the development of energy estimation and management solutions is an important research topic to better optimize the use of available energy supply and generation potential. In this work, we revisit the challenges behind the project design and construction for two fully autonomous sailboats and propose a methodology based on the Restricted Boltzmann Machine (RBM) in order to find the best way to manage the supplementary energy generated by solar panels. To verify the approach, we introduce a case study with our two developed sailboats that have planned payload with electric and electronics, and one of them is equipped with an electrical engine that may eventually help with the sailboat propulsion. Our current results show that it is possible to augment the system confidence level for the potential energy that can be harvested from the environment and the remaining energy stored, optimizing the energy usage of autonomous vehicles and improving their energy robustness.

13.
ACS Appl Mater Interfaces ; 14(49): 54478-54487, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36448730

RESUMO

Tumor microenvironment (TME) responsive chemodynamic therapy (CDT) showed an important application in inhibiting tumor growth by producing the highly toxic hydroxyl radical (·OH), but insufficient hydrogen peroxide (H2O2) and overexpressed glutathione (GSH) limited its application. Herein, by integrating photothermal therapy (PTT) and CDT, a new kind of mesoporous polydopamine (MPDA)-based cascade-reaction nanoplatform (MPDA@AuNPs-Cu) was designed for enhanced antitumor therapy, in which ultrasmall gold nanoparticles (AuNPs) with glucose oxidase (GOx)-like activity were deposited on MPDA for providing H2O2, and Cu2+ was chelated for GSH-responsive Fenton-like reaction. It was demonstrated that the MPDA@AuNPs-Cu nanoprobe showed high photothermal conversion efficiency and excellent biocompatibility. Moreover, the MPDA@AuNPs-Cu nanoprobe exhibited strong ·OH generation because of H2O2 self-generation and photothermal stimulation. Importantly, compared with MPDA-Cu, MPDA@AuNPs-Cu exhibited enhanced in vitro and in vivo CDT/PTT performance, by which the tumor growth was completely inhibited, achieving TME-responsive antitumor efficacy.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Neoplasias , Humanos , Ouro/farmacologia , Peróxido de Hidrogênio , Glutationa , Linhagem Celular Tumoral , Microambiente Tumoral
14.
Acta Pharm Sin B ; 12(1): 406-423, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35127395

RESUMO

Incorporation of multiple functions into one nanoplatform can improve cancer diagnostic efficacy and enhance anti-cancer outcomes. Here, we constructed doxorubicin (DOX)-loaded silk fibroin-based nanoparticles (NPs) with surface functionalization by photosensitizer (N770). The obtained nanotheranostics (N770-DOX@NPs) had desirable particle size (157 nm) and negative surface charge (-25 mV). These NPs presented excellent oxygen-generating capacity and responded to a quadruple of stimuli (acidic solution, reactive oxygen species, glutathione, and hyperthermia). Surface functionalization of DOX@NPs with N770 could endow them with active internalization by cancerous cell lines, but not by normal cells. Furthermore, the intracellular NPs were found to be preferentially retained in mitochondria, which were also efficient for near-infrared (NIR) fluorescence imaging, photothermal imaging, and photoacoustic imaging. Meanwhile, DOX could spontaneously accumulate in the nucleus. Importantly, a mouse test group treated with N770-DOX@NPs plus NIR irradiation achieved the best tumor retardation effect among all treatment groups based on tumor-bearing mouse models and a patient-derived xenograft model, demonstrating the unprecedented therapeutic effects of trimodal imaging-guided mitochondrial phototherapy (photothermal therapy and photodynamic therapy) and chemotherapy. Therefore, the present study brings new insight into the exploitation of an easy-to-use, versatile, and robust nanoplatform for programmable targeting, imaging, and applying synergistic therapy to tumors.

15.
ACS Appl Mater Interfaces ; 14(51): 56644-56657, 2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36515637

RESUMO

Direct hypoxia alleviation and lactate depletion in the tumor microenvironment (TME) are promising for effective cancer therapy but still very challenging. To address this challenge, the current research directly reshapes the TME for inhibiting tumor growth and activating the antitumor immunity using a drug-free nanozyme. Herein, the acid-sensitive nanozymes were constructed based on peroxidized layered double hydroxide nanoparticles for O2 self-supply and self-boosted lactate depletion. The coloading of partially cross-linked catalase and lactate oxidase enabled the acid-sensitive nanozymes to promote three reactions, that is, (1) H2O2 generation from MgO2 hydrolysis (30% at pH 7.4 vs 63% at pH 6.0 in 8 h); (2) O2 generation from H2O2 (12% at pH 7.4 vs 21% at pH 6.0 in 2 h); and (3) lactate depletion by in situ generated O2 (50% under hypoxia vs 75% under normoxia in 24 h in vitro) in parallel or tandem. These promoted reactions together efficiently induced colon cancer cell apoptosis under the hypoxic conditions, significantly inhibited tumor growth (>95%), and suppressed distant tumor growth upon seven administrations in every 3 days and moreover transformed the immunosuppressive tumor into "hot" one in the colon tumor-bearing mouse model. This is the first example for a nanozyme that supplies sufficient O2 for hypoxia relief and lactate depletion, thus providing a new insight into drug-free nanomaterial-mediated TME-targeted cancer therapy.


Assuntos
Nanopartículas , Neoplasias , Animais , Camundongos , Linhagem Celular Tumoral , Ácido Láctico/farmacologia , Peróxido de Hidrogênio/farmacologia , Neoplasias/tratamento farmacológico , Hipóxia , Microambiente Tumoral
16.
J Colloid Interface Sci ; 557: 580-590, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31550650

RESUMO

Protecting active species from aggregation and corrosion may be feasible to obtain stable catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, bamboo-shaped N-doped carbon nanotubes (hollow BS-NCNTs as shells) are self-generated to in situ wrap the Co/CoOx schottky junctions (cores) to obtain the Co/CoOx@BS-NCNTs as bifunctional ORR/OER catalysts by using the Co-chelated melamine precursor. For ORR, Co/CoOx@BS-NCNTs (700 °C) exhibits more positive peak (0.822 V vs. RHE) and half-wave (0.842 V vs. RHE) potential than those of commercial Pt/C (10 wt%). Superior ORR activity is mainly attributed to the enriched coordination-unsaturated Co2+ (tetrahedral CoTd2+) in the CoOx wrapped in the tubular structure of BS-NCNTs featuring high electrical conductivity and active N species. Moreover, the π-π bonds of CNTs are activated by N substitution, which provides a stunning electron capture and transmission capability for enhancing ORR activity. For OER, Co/CoOx@BS-NCNTs (700 °C) obtains a smaller potential (1.590 V vs. RHE) than that of RuO2/C at 10 mA cm-2. The outstanding OER activity and durability of Co/CoOx@BS-NCNTs (700 °C) originates from strong interactions between C-skeleton and Co species, and efficient Co3+/Co4+ (Co4+OOH as active sites) transition protected by the externally-grown CNTs. Furthermore, abundant oxygen vacancies on CoOx surface can facilitate the adsorption of OH-/or OER-related intermediates to improve OER activity. Therefore, this study provides a promising strategy to develop NCNTs-wrapped Co species with high catalytic activity and stability for energy conversion.

17.
Biomaterials ; 177: 67-77, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29885587

RESUMO

A combinatorial therapy that utilizes two or more therapeutic modalities is more effective in overcoming the limitations than each individual method used alone. Despite great advances have been achieved, the combination of chemotherapy and photodynamic therapy (PDT) still cannot satisfy the clinic requirements as the antitumor efficacy could be severely affected by tumor-associated hypoxia. Herein, for the first time, we reported a platinum(IV) complex-based polyprodrug that can in situ generate the highly toxic platinum(II) species as chemotherapeutics and simultaneously induce a high level of reactive oxygen species (ROS) in a PDT-like process without the use of photosensitizer and consumption of oxygen. By in situ polymerizing the platinum(IV) complex-based prodrug monomer (PPM) and 2-methacryloyloxy ethyl phosphorylcholine (MPC), nanosized hydrogel-like polyprodrug could be synthesized. Upon being exposed to light, Pt(IV) moieties in this photoactivable polyprodrug were reduced to generate Pt(II) species. At the meantime, a high level of ROS was generated without the presence of endogenous oxygen, which was confirmed by electron spin resonance (ESR) and fluorescence probes. With the unique nanosized architecture and photoresponsive feature, the as-synthesized polyprodrug exhibited the advantages of sustained drug release, long-term circulation, preferable tumor accumulation, and reversing drug resistance by downregulating the expression of multidrug resistance-associated protein 1 (MRP1) in the anticancer treatment.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Compostos Organoplatínicos/uso terapêutico , Pró-Fármacos/uso terapêutico , Células A549 , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Humanos , Camundongos Endogâmicos BALB C , Neoplasias/metabolismo , Neoplasias/patologia , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacocinética , Fotoquimioterapia , Pró-Fármacos/química , Pró-Fármacos/farmacocinética , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Oxigênio Singlete/metabolismo , Hipóxia Tumoral/efeitos dos fármacos
18.
Front Psychol ; 9: 2440, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30631290

RESUMO

Self-generation of knowledge can activate deeper cognitive processing and improve long-term retention compared to the passive reception of information. It plays a distinctive role within the concept of inquiry-based learning, which is an activity-oriented, student-centered collaborative learning approach in which students become actively involved in knowledge construction by following an idealized hypothetico-deductive method. This approach allows students to not only acquire content knowledge, but also an understanding of investigative procedures/inquiry skills - in particular the control-of-variables strategy (CVS). From the perspective of cognitive load theory, generating answers and solutions during inquiry-based learning is inefficient as it imposes an intrinsic and extraneous load on learners. Previous research on self-generation of content knowledge in inquiry-based learning has demonstrated that (1) a high cognitive load impairs retention of the generated information, (2) feedback is a fundamental requirement for self-generation of complex content knowledge, (3) self-generation success is key to long-term retention, and (4) generating and rereading place different demands on learners. However, there is still no research on the self-generation of scientific reasoning skills (procedural knowledge) and no knowledge of interaction between the (long-term) retention of these skills with prior knowledge, feedback and self-generation success. That is why this experiment was conducted. The focus of this research is to analyze the distinctive role of self-generation of scientific reasoning skills within the concept of inquiry-based learning and to identify the influence of prior knowledge and self-generation success on short-term and long-term retention. For this purpose, an experiment involving 133 6th and 7th graders was conducted. An inquiry activity that included the self-generation of scientific reasoning skills was compared to an inquiry task that had students simply read information about the experimental design. We used both an immediate and a delayed test to examine which treatment better developed a deeper understanding of CVS and an ability to apply this knowledge to novel problems (transfer). Direct instruction was clearly superior to self-generation in facilitating students' acquisition of CVS immediately after the inquiry task. However, after a period of 1 week had elapsed, both treatment conditions turned out to be equally effective. A generation effect was only found among students with high self-generation success after a 1-week delay.

19.
Acta Pharmaceutica Sinica B ; (6): 406-423, 2022.
Artigo em Inglês | WPRIM | ID: wpr-929303

RESUMO

Incorporation of multiple functions into one nanoplatform can improve cancer diagnostic efficacy and enhance anti-cancer outcomes. Here, we constructed doxorubicin (DOX)-loaded silk fibroin-based nanoparticles (NPs) with surface functionalization by photosensitizer (N770). The obtained nanotheranostics (N770-DOX@NPs) had desirable particle size (157 nm) and negative surface charge (-25 mV). These NPs presented excellent oxygen-generating capacity and responded to a quadruple of stimuli (acidic solution, reactive oxygen species, glutathione, and hyperthermia). Surface functionalization of DOX@NPs with N770 could endow them with active internalization by cancerous cell lines, but not by normal cells. Furthermore, the intracellular NPs were found to be preferentially retained in mitochondria, which were also efficient for near-infrared (NIR) fluorescence imaging, photothermal imaging, and photoacoustic imaging. Meanwhile, DOX could spontaneously accumulate in the nucleus. Importantly, a mouse test group treated with N770-DOX@NPs plus NIR irradiation achieved the best tumor retardation effect among all treatment groups based on tumor-bearing mouse models and a patient-derived xenograft model, demonstrating the unprecedented therapeutic effects of trimodal imaging-guided mitochondrial phototherapy (photothermal therapy and photodynamic therapy) and chemotherapy. Therefore, the present study brings new insight into the exploitation of an easy-to-use, versatile, and robust nanoplatform for programmable targeting, imaging, and applying synergistic therapy to tumors.

20.
Biotech Histochem ; 91(4): 283-95, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27008034

RESUMO

We describe a new scaffold-free three-dimensional (3D) cell culture model using cholesteryl ester based lyotropic liquid crystal (LC) substrates. Keratinocytes were deposited randomly on the LC surface where they self-assembled into 3D microtissues or keratinospheroids. The cell density required to form spheroids was optimized. We investigated cell viability using dead/live cell assays. The adhesion characteristics of cells within the microtissues were determined using histological sectioning and immunofluorescence staining. Fourier transform infrared spectroscopy (FTIR) was used to characterize the biochemistry of the keratinospheroids. We found that both cells and microtissues could migrate on the LC surface. The viability study indicated approximately 80% viability of cells in the microtissues up to 20 days of culture. Strong intercellular adhesion was observed in the stratification of the multi-layered microspheroids using field emission-scanning electron microscopy (FE-SEM) and histochemical staining. The cytoskeleton and vinculins of the cells in the microtissues were expressed diffusely, but the microtissues were enriched with lipids and nucleic acids, which indicates close resemblance to the conditions in vivo. The basic 3D culture model based on LC may be used for cell and microtissue migration studies in response to cytochemical treatment.


Assuntos
Técnicas de Cultura de Células/métodos , Queratinócitos/citologia , Cristais Líquidos , Engenharia Tecidual , Linhagem Celular , Sobrevivência Celular , Imunofluorescência , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier
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