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1.
Dev Sci ; 25(4): e13223, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34962696

RESUMO

How do people learn about things that they have never perceived or inferred-like molecules, miracles or Marie-Antoinette? For many thinkers, trust is the answer. Humans rely on communicated information, sometimes even when it contradicts blatantly their firsthand experience. We investigate the early ontogeny of this trust using a non-verbal search paradigm in four main studies and three supplementary studies (N = 208). Infants and toddlers first see where a reward is, and then an informant communicates to them that it is in another location. We use this general experimental set-up to assess the role of age, informants' knowledge, cue's familiarity, and communicative context on trust in communicated information. Results reveal that infants and toddlers quickly trust familiar and novel communicative cues from well-informed adults. When searching for the reward, they follow a well-informed adults' communicative cue, even when it contradicts what they just saw. Furthermore, infants are less likely to be guided by familiar and novel cues from poorly informed adults than toddlers. Thus, reliance on communication is calibrated during early childhood, up to the point of overriding evidence about informants' knowledge. Moreover, toddlers trust much more strongly a novel cue when it is used in a communicative manner. Toddlers' trust cannot be explained by mere compliance: it is highly reduced when communicated information is pitted against what participants currently see. Thus, humans' strong tendency to rely on familiar and novel communicative cues emerges in infancy, and intensifies during the second year of life.


Assuntos
Sinais (Psicologia) , Confiança , Adulto , Pré-Escolar , Comunicação , Humanos , Lactente , Aprendizagem , Reconhecimento Psicológico
2.
Sensors (Basel) ; 22(10)2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35632371

RESUMO

In spite of its pivotal role in the characterization of humoral immunity, there is no accepted method for the absolute quantitation of antigen-specific serum antibodies. We devised a novel method to quantify polyclonal antibody reactivity, which exploits protein microspot assays and employs a novel analytical approach. Microarrays with a density series of disease-specific antigens were treated with different serum dilutions and developed for IgG and IgA binding. By fitting the binding data of both dilution series to a product of two generalized logistic functions, we obtained estimates of antibody reactivity of two immunoglobulin classes simultaneously. These estimates are the antigen concentrations required for reaching the inflection point of thermodynamic activity coefficient of antibodies and the limiting activity coefficient of antigen. By providing universal chemical units, this approach may improve the standardization of serological testing, the quality control of antibodies and the quantitative mapping of the antibody-antigen interaction space.


Assuntos
Imunoglobulina A , Imunoglobulina G , Antígenos , Imunoglobulina G/metabolismo
3.
BMC Public Health ; 21(1): 1707, 2021 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-34538241

RESUMO

BACKGROUND: In Hungary, the mortality rate for testicular germ cell cancer (TGCC) is 0,9/100000 which is significantly higher than the EU average. We prospectively evaluated the effect of socioeconomic position on patient delay and therapy outcomes. METHODS: Questionnaires on subjective social status (MacArthur Subjective Status Scale), objective socioeconomic position (wealth, education, and housing data), and on patient's delay were completed by newly diagnosed TGCC patients. RESULTS: Patients belonged to a relatively high socioeconomic class, a university degree was double the Hungarian average, Cancer-specific mortality in the highest social quartile was 1.56% while in the lowest social quartile 13.09% (p = 0.02). In terms of patient delay, 57.2% of deceased patients waited more than a year before seeking help, while this number for the surviving patients was 8.0% (p = 0.0000). Longer patient delay was associated with a more advanced stage in non-seminoma but not in seminoma, the correlation coefficient for non-seminoma was 0.321 (p < 0.001). For patient delay, the most important variables were the mother's and patient's education levels (r = - 0.21, p = 0.0003, and r = - 0.20, p = 0.0005), respectively. Since the patient delay was correlated with the social quartile and resulted in a more advanced stage in non-seminoma, the lower social quartile resulted in higher mortality in non-seminoma patients (p = 0.005) but not in seminoma patients (p = 0.36) where the patient delay was not associated with a more advanced stage. CONCLUSIONS: Based on our result, we conclude that to improve survival, we should promote testicular cancer awareness, especially among the most deprived populations, and their health care providers.


Assuntos
Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Humanos , Hungria/epidemiologia , Masculino , Neoplasias Embrionárias de Células Germinativas/terapia , Estudos Prospectivos , Fatores de Risco , Fatores Socioeconômicos , Neoplasias Testiculares/terapia
4.
Proc Natl Acad Sci U S A ; 115(45): 11477-11482, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30322932

RESUMO

A current debate in psychology and cognitive science concerns the nature of young children's ability to attribute and track others' beliefs. Beliefs can be attributed in at least two different ways: prospectively, during the observation of belief-inducing situations, and in a retrospective manner, based on episodic retrieval of the details of the events that brought about the beliefs. We developed a task in which only retrospective attribution, but not prospective belief tracking, would allow children to correctly infer that someone had a false belief. Eighteen- and 36-month-old children observed a displacement event, which was witnessed by a person wearing sunglasses (Experiment 1). Having later discovered that the sunglasses were opaque, 36-month-olds correctly inferred that the person must have formed a false belief about the location of the objects and used this inference in resolving her referential expressions. They successfully performed retrospective revision in the opposite direction as well, correcting a mistakenly attributed false belief when this was necessary (Experiment 3). Thus, children can compute beliefs retrospectively, based on episodic memories, well before they pass explicit false-belief tasks. Eighteen-month-olds failed in such a task, suggesting that they cannot retrospectively attribute beliefs or revise their initial belief attributions. However, an additional experiment provided evidence for prospective tracking of false beliefs in 18-month-olds (Experiment 2). Beyond identifying two different modes for tracking and updating others' mental states early in development, these results also provide clear evidence of episodic memory retrieval in young children.


Assuntos
Antecipação Psicológica/fisiologia , Cognição/fisiologia , Formação de Conceito/fisiologia , Rememoração Mental/fisiologia , Psicologia da Criança , Desenvolvimento Infantil , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Memória Episódica , Percepção Social , Fatores de Tempo
5.
Infancy ; 26(1): 4-38, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33306867

RESUMO

Determining the meanings of words requires language learners to attend to what other people say. However, it behooves a young language learner to simultaneously encode relevant non-verbal cues, for example, by following the direction of their eye gaze. Sensitivity to cues such as eye gaze might be particularly important for bilingual infants, as they encounter less consistency between words and objects than monolingual infants, and do not always have access to the same word-learning heuristics (e.g., mutual exclusivity). In a preregistered study, we tested the hypothesis that bilingual experience would lead to a more pronounced ability to follow another's gaze. We used a gaze-following paradigm developed by Senju and Csibra (Current Biology, 18, 2008, 668) to test a total of 93 6- to 9-month-old and 229 12- to 15-month-old monolingual and bilingual infants, in 11 laboratories located in 8 countries. Monolingual and bilingual infants showed similar gaze-following abilities, and both groups showed age-related improvements in speed, accuracy, frequency, and duration of fixations to congruent objects. Unexpectedly, bilinguals tended to make more frequent fixations to on-screen objects, whether or not they were cued by the actor. These results suggest that gaze sensitivity is a fundamental aspect of development that is robust to variation in language exposure.


Assuntos
Desenvolvimento Infantil/fisiologia , Movimentos Oculares/fisiologia , Desenvolvimento da Linguagem , Multilinguismo , Percepção Social , Percepção Visual/fisiologia , Tecnologia de Rastreamento Ocular , Feminino , Fixação Ocular/fisiologia , Humanos , Lactente , Masculino
6.
Behav Brain Sci ; 44: e149, 2021 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-34796829

RESUMO

The authors distinguish knowledge and belief attributions, emphasizing the role of the former in mental-state attribution. This does not, however, warrant diminishing interest in the latter. Knowledge attributions may not entail mental-state attributions or metarepresentations. Even if they do, the proposed features are insufficient to distinguish them from belief attributions, demanding that we first understand each underlying representation.


Assuntos
Conhecimento , Percepção Social , Humanos
7.
Proc Natl Acad Sci U S A ; 113(49): 14109-14114, 2016 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-27872279

RESUMO

Recently, an alternative renin-angiotensin system pathway has been described, which involves binding of angiotensin-(1-7) to its receptor Mas. The Mas axis may counterbalance angiotensin-II-mediated proinflammatory effects, likely by affecting macrophage function. Here we investigate the role of Mas in murine models of autoimmune neuroinflammation and atherosclerosis, which both involve macrophage-driven pathomechanisms. Mas signaling affected macrophage polarization, migration, and macrophage-mediated T-cell activation. Mas deficiency exacerbated the course of experimental autoimmune encephalomyelitis and increased macrophage infiltration as well as proinflammatory gene expression in the spleen and spinal cord. Furthermore, Mas deficiency promoted atherosclerosis by affecting macrophage infiltration and migration and led to increased oxidative stress as well as impaired endothelial function in ApoE-deficient mice. In summary, we identified the Mas axis as an important factor in macrophage function during inflammation of the central nervous and vascular system in vivo. Modulating the Mas axis may constitute an interesting therapeutic target in multiple sclerosis and/or atherosclerosis.


Assuntos
Aterosclerose/metabolismo , Encefalomielite Autoimune Experimental/metabolismo , Macrófagos/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Aterosclerose/imunologia , Aterosclerose/fisiopatologia , Diferenciação Celular , Movimento Celular , Proliferação de Células , Encefalomielite Autoimune Experimental/imunologia , Endotélio Vascular/fisiopatologia , Feminino , Expressão Gênica , Masculino , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Proto-Oncogene Mas , Medula Espinal/metabolismo , Baço/metabolismo , Linfócitos T/fisiologia
8.
Infancy ; 24(5): 738-751, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32677281

RESUMO

Past research has accumulated evidence regarding infants' false-belief understanding, measuring their gaze patterns or active helping behaviors. However, the underlying mechanisms are still debated, specifically, whether young infants can compute that others represent the world under a certain aspect. Such performance requires holding in mind two representations about the same object simultaneously and attributing only one to another person. While 14-month-olds can encode an object under different aspects when forming first-person representations, it is unclear whether infants at this very age could also predict others' behavior based on their beliefs about an object's identity. Here, we investigate this question in a novel eye-tracking-based unexpected-identity task. We measured 14-month-olds' anticipatory looks combined with their looking time, using a violation-of-expectation paradigm. Results show that 14-month-olds look longer to an actor's reach that is incongruent with her false belief about the identity of an object compared to a congruent reach. Furthermore, infants correctly anticipated the actor's reach based on her false belief. Thus, as soon as infants represent dual identities they can integrate them in belief attributions and use them for consequent behavioral predictions. Such data provide evidence for the flexibility of false-belief attributions and support proposals arguing for infants' rich theory-of-mind abilities.

9.
Psychol Sci ; 29(4): 614-622, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29447070

RESUMO

Recent studies have demonstrated people's propensity to adopt others' visuospatial perspectives (VSPs) in a shared physical context. The present study investigated whether spontaneous VSP taking occurs in mental space where another person's perspective matters for mental activities rather than physical actions. Participants sat at a 90° angle to a confederate and performed a semantic categorization task on written words. From the participants' point of view, words were always displayed vertically, while for the confederate, these words appeared either the right way up or upside down, depending on the confederate's sitting position. Participants took longer to categorize words that were upside down for the confederate, suggesting that they adopted the confederate's VSP without being prompted to do so. Importantly, the effect disappeared if the other's visual access was impeded by opaque goggles. This demonstrates that human adults show a spontaneous sensitivity to others' VSP in the context of mental activities, such as joint reading.


Assuntos
Reconhecimento Visual de Modelos , Desempenho Psicomotor , Tempo de Reação , Percepção Espacial , Teoria da Mente , Feminino , Humanos , Masculino , Adulto Jovem
10.
Langmuir ; 34(8): 2619-2629, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29381069

RESUMO

Despite the success of plasma-enhanced atomic layer deposition (PEALD) in depositing quality silicon nitride films, a fundamental understanding of the growth mechanism has been difficult to obtain because of lack of in situ characterization to probe the surface reactions noninvasively and the complexity of reactions induced/enhanced by the plasma. These challenges have hindered the direct observation of intermediate species formed during the reactions. We address this challenge by examining the interaction of Ar plasma using atomically flat, monohydride-terminated Si(111) as a well-defined model surface and focusing on the initial PEALD with aminosilanes. In situ infrared and X-ray photoelectron spectroscopy reveals that an Ar plasma induces desorption of H atoms from H-Si(111) surfaces, leaving Si dangling bonds, and that the reaction of di-sec-butylaminosilane (DSBAS) with Ar plasma-treated surfaces requires the presence of both active sites (Si dangling bonds) and Si-H; there is no reaction on fully H-terminated or activated surfaces. By contrast, high-quality hydrofluoric acid-etched Si3N4 surfaces readily react with DSBAS, resulting in the formation of O-SiH3. However, the presence of back-bonded oxygen in O-SiH3 inhibits H desorption by Ar or N2 plasma, presumably because of stabilization of H against ion-induced desorption. Consequently, there is no reaction of adsorbed aminosilanes even after extensive Ar or N2 plasma treatments; a thermal process is necessary to partially remove H, thereby promoting the formation of active sites. These observations are consistent with a mechanism requiring the presence of both undercoordinated nitrogen and/or dangling bonds and unreacted surface hydrogen. Because active sites are involved, the PEALD process is found to be sensitive to the duration of the plasma exposure treatment and the purge time, during which passivation of these sites can occur.

11.
Dev Sci ; 20(6)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29076269

RESUMO

In their first years, infants acquire an incredible amount of information regarding the objects present in their environment. While often it is not clear what specific information should be prioritized in encoding from the many characteristics of an object, different types of object representations facilitate different types of generalizations. We tested the hypotheses that 1-year-old infants distinctively represent familiar objects as exemplars of their kind, and that ostensive communication plays a role in determining kind membership for ambiguous objects. In the training phase of our experiment, infants were exposed to movies displaying an agent sorting objects from two categories (cups and plates) into two locations (left or right). Afterwards, different groups of infants saw either an ostensive or a non-ostensive demonstration performed by the agent, revealing that a new object that looked like a plate can be transformed into a cup. A third group of infants experienced no demonstration regarding the new object. During test, infants were presented with the ambiguous object in the plate format, and we measured generalization by coding anticipatory looks to the plate or the cup side. While infants looked equally often towards the two sides when the demonstration was non-ostensive, and more often to the plate side when there was no demonstration, they performed more anticipatory eye movements to the cup side when the demonstration was ostensive. Thus, ostensive demonstration likely highlighted the hidden dispositional properties of the target object as kind-relevant, guiding infants' categorization of the foldable cup as a cup, despite it looking like a plate. These results suggest that infants likely encode familiar objects as exemplars of their kind and that ostensive communication can play a crucial role in disambiguating what kind an object belongs to, even when this requires disregarding salient surface features.


Assuntos
Atenção/fisiologia , Comunicação , Movimentos Oculares/fisiologia , Comportamento do Lactente/fisiologia , Percepção Visual/fisiologia , Feminino , Humanos , Lactente , Masculino , Estimulação Luminosa , Distribuição Aleatória
12.
Proc Biol Sci ; 282(1819)2015 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-26559949

RESUMO

A major feat of social beings is to encode what their conspecifics see, know or believe. While various non-human animals show precursors of these abilities, humans perform uniquely sophisticated inferences about other people's mental states. However, it is still unclear how these possibly human-specific capacities develop and whether preverbal infants, similarly to adults, form representations of other agents' mental states, specifically metarepresentations. We explored the neurocognitive bases of eight-month-olds' ability to encode the world from another person's perspective, using gamma-band electroencephalographic activity over the temporal lobes, an established neural signature for sustained object representation after occlusion. We observed such gamma-band activity when an object was occluded from the infants' perspective, as well as when it was occluded only from the other person (study 1), and also when subsequently the object disappeared, but the person falsely believed the object to be present (study 2). These findings suggest that the cognitive systems involved in representing the world from infants' own perspective are also recruited for encoding others' beliefs. Such results point to an early-developing, powerful apparatus suitable to deal with multiple concurrent representations, and suggest that infants can have a metarepresentational understanding of other minds even before the onset of language.


Assuntos
Desenvolvimento Infantil , Cognição , Compreensão , Percepção Social , Percepção Visual , Eletroencefalografia , Humanos , Lactente , Lobo Temporal/fisiologia
13.
Phys Chem Chem Phys ; 16(34): 18501-12, 2014 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-25072273

RESUMO

A detailed reaction mechanism has been proposed for the full ALD cycle of Si3N4 deposition on the ß-Si3N4(0001) surface using bis(diethylamino)silane (BDEAS) or bis(tertiarybutylamino)silane (BTBAS) as a Si precursor with NH3 acting as the nitrogen source. Potential energy landscapes were derived for all elementary steps in the proposed reaction network using a periodic slab surface model in the density functional approximation. Although the dissociative reactivity of BTBAS was slightly better than that of BDEAS, the thermal deposition process was still found to be an inherently high temperature process due to the high activation energies during the dissociative chemisorption of both precursors and the surface re-amination steps. These results underline the need to develop new precursors and alternative nitrogen sources when low temperature thermal silicon nitride films are targeted.

14.
Cognition ; 249: 105812, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38763072

RESUMO

Successful interactions require not only representing others' mental states but also flexibly updating them, whenever one's original inferences may no longer hold. Such situations arise, for instance, when a partner's behavior is incongruent with one's expectations. Although these situations are rather common, the question whether people update others' mental states spontaneously upon encountering unexpected behaviors and whether they use the updated mental states in novel contexts, has been largely unexplored. We addressed these issues in two experiments. In each experiment participants first performed an anticipatory looking task, reacting to a virtual 'partner', who categorized pictures based on their ambiguous or non-ambiguous color. Importantly, to perform the task participants did not have to track their partner's perspective. Following a correct categorization phase, the 'partner' started to systematically miscategorize one of the ambiguous colors (e.g., as if she would now believe that the greenish blue is green). We measured how participants' anticipatory looking preceding the partner's categorization changed across trials. Afterward, we asked whether participants implicitly transferred their knowledge about the partner's updated perspective to a new task. Finally, they performed an explicit perspective-taking task, to test whether they selectively updated the partner's perspective, but not their own. Results revealed that correct anticipations started to emerge only after a few miscategorizations, indicating the spontaneous updating of the other's perspective regarding the miscategorized color. Signatures of updating emerged somewhat earlier when the partner made similarity judgments (Experiment 2), highlighting the subjective nature of her decisions, compared to when following an explicit color-categorization rule (Experiment 1). In the explicit perspective-taking task of both experiments, roughly half of the participants could categorize items according to the partner's (spontaneously updated) perspective and also used their partner's updated perspective in the implicit transfer task to some degree, while they were the ones who displayed more pronounced anticipatory patterns as well. Such data provides strong evidence that the observed changes in anticipatory looking reflect spontaneous and flexible mental state updating. In addition, the findings also point to a high individual variability both in the updating of attributed mental states and the use of the updated mental state content.


Assuntos
Movimentos Oculares , Percepção Social , Humanos , Feminino , Masculino , Adulto Jovem , Adulto , Movimentos Oculares/fisiologia , Teoria da Mente/fisiologia , Percepção de Cores/fisiologia , Interação Social
15.
Sci Rep ; 14(1): 4971, 2024 02 29.
Artigo em Inglês | MEDLINE | ID: mdl-38424102

RESUMO

The ability to take each other's visuospatial perspective has been linked to people's capacity to perceive another's action possibilities and to predict their actions. Research has also shown that visuospatial perspective taking is supported by one's own mental own-body transformation. However, how these two processes of action perception and visuospatial perspective taking might interact remains largely unknown. By introducing seven angular disparities between participants and the model in the stimuli pictures across "Action" and "No Action" conditions, we investigated whether the observation of a goal-directed action facilitates perspective taking and whether this facilitation depends on the level of mental own-body transformation required to take perspective. The results showed that action observation facilitated performance independently of the level of mental-own body transformation. The processes behind this facilitation could involve anatomical mapping that is independent of the congruency between the participants' and the model's perspectives. Further, we replicated previous research findings, showing that participants were more accurate and faster when taking the perspective of a person compared to an inanimate object (a chair). The strongest facilitation effects were seen at the highest angular disparities between participants and the model in the stimuli pictures. Together, these findings enhance our knowledge of the mechanisms behind visuospatial perspective taking.


Assuntos
Motivação , Movimento , Humanos , Previsões
16.
Animals (Basel) ; 14(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38473196

RESUMO

Metacarpophalangeal joint region pain is a common cause of lameness in racehorses. Radiological abnormalities in the sagittal ridge (SR) of the third metacarpal bone have been associated with joint effusion, lameness and reduced sales prices. The aims were to describe computed tomographic (CT) appearance of the SR in racehorses, and to document the progression of these findings over three assessments. Forty yearlings were enrolled at the first examination (time 0). Re-examinations were performed twice, approximately six months apart on 31 (time 1) and 23 (time 2) horses, respectively. Computed tomographic examinations of both metacarpophalangeal regions were performed with the horses in a standing position. Computed tomographic reconstructions were analysed subjectively and objectively. The mean Hounsfield Unit values (Hus) of eight radial segments and location, size and shape of hypoattenuating lesions were recorded. Mean Hus at time 1 were higher than at time 0. There was no difference between mean HU at times 1 and 2. The mean HU values of the dorsal half were higher in the right forelimbs and in fillies. Hypoattenuation was identified in 33/80 (41.3%) limbs at time 0, in 22/62 (35.5%) limbs at time 1 and in 14/46 (30.4%) limbs at time 2. All hypoattenuations were located in the dorsodistal aspect of the SR. The most common shapes were hypoattenuating lesions elongated proximodistally and those extending towards trabecular bone. An increase in attenuation of the SR occurred in the first six months of training. Hypoattenuating lesions could decrease in size and could resolve during early training. In this population, these lesions were not associated with lameness.

17.
Open Mind (Camb) ; 7: 435-444, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37637294

RESUMO

Successful social interactions rely on flexibly tracking and revising others' beliefs. These can be revised prospectively, new events leading to new beliefs, or retrospectively, when realizing that an attribution may have been incorrect. However, whether infants are capable of such belief revisions is an open question. We tested whether 18-month-olds can revise an attributed FB into a TB when they learn that a person may have witnessed an event that they initially thought she could not see. Infants first observed Experimenter 1 (E1) hiding two objects into two boxes. Then E1 left the room, and the locations of the objects were swapped. Infants then accompanied Experimenter 2 (E2) to the adjacent room. In the FB-revised-to-TB condition, infants observed E1 peeking into the experimental room through a one-way mirror, whereas in the FB-stays-FB condition, they observed E1 reading a book. After returning to the experimental room E1 requested an object by pointing to one of the boxes. In the FB-stays-FB condition, most infants chose the non-referred box, congruently with the agent's FB. However, in the FB-revised-to-TB condition, most infants chose the other, referred box. Thus, 18-month-olds revised an already attributed FB after receiving evidence that this attribution might have been wrong.

18.
Bioengineering (Basel) ; 10(9)2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37760197

RESUMO

BACKGROUND: Surgeries of severe periacetabular bone defects (Paprosky ≥ 2B) are a major challenge in current practice. Although solutions are available for this serious clinical problem, they all have their disadvantages as well as their advantages. An alternative method of reconstructing such extensive defects was the use of a cup with a stem to solve these revision situations. As the instrumentation offered is typically designed for scenarios where a significant bone defect is not present, our unique technique has been developed for implantation in cases where reference points are missing. Our hypothesis was that a targeting device designed based on the CT scan of a patient's pelvis could facilitate the safe insertion of the guiding wire. METHODS: Briefly, our surgical solution consists of a two-step operation. If periacetabular bone loss was found to be more significant during revision surgery, all implants were removed, and two titanium marker screws in the anterior iliac crest were percutaneously inserted. Next, by applying the metal artifact removal (MAR) algorithm, a CT scan of the pelvis was performed. Based on that, the dimensions and positioning of the cup to be inserted were determined, and a patient-specific 3D printed targeting device made of biocompatible material was created to safely insert the guidewire, which is essential to the implantation process. RESULTS: In this study, medical, engineering, and technical tasks related to the design, the surgical technique, and experiences from 17 surgical cases between February 2018 and July 2021 are reported. There were no surgical complications in any cases. The implant had to be removed due to septic reasons (independently from the technique) in a single case, consistent with the septic statistics for this type of surgery. There was not any perforation of the linea terminalis of the pelvis due to the guiding method. The wound healing of patients was uneventful, and the implant was fixed securely. Following rehabilitation, the joints were able to bear weight again. After one to four years of follow-up, the patient satisfaction level was high, and the gait function of the patients improved a lot in all cases. CONCLUSIONS: Our results show that CT-based virtual surgical planning and, based on it, the use of a patient-specific 3D printed aiming device is a reliable method for major hip surgeries with significant bone loss. This technique has also made it possible to perform these operations with minimal X-ray exposure.

19.
Sci Rep ; 13(1): 11985, 2023 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-37491550

RESUMO

All types of cranioplasty techniques restore the morphology of the skull and affect patient aesthetics. Safe and easy techniques are required to enhance patients' recovery and the rehabilitation process. We propose a new method of cranioplasty. The 3-dimensional (3D) reconstruction of a thin-layer computed tomography (CT) scan of the skull was used to reflect the intact side onto the defect and subtract the overlapping points from one another. In this way, a 3D model of the planned implant can be built in the required shape and size. The precise fit of the implant can be checked by printing the defective part of the skull in case it can be modified. A sterilisable silicone mould based on the finalized model was created afterwards. Polymethyl methacrylate implants were prepared directly in an aseptic environment in the operating room during surgery. Between 2005 and 2020, we performed 54 cranioplasties on 52 patients whose craniotomies were performed previously for indications of traumatic brain injury, stroke or tumour surgeries. No technical problems were noted during the operations. In 2 cases, septic complications that occurred were not connected to the technique itself, and the implants were removed and later replaced. Our proposed technique based on 3D-printed individual silicone moulds is a reliable, safe, easily reproducible and low-cost method to repair different skull defects.


Assuntos
Procedimentos de Cirurgia Plástica , Polimetil Metacrilato , Humanos , Silicones , Crânio/cirurgia , Próteses e Implantes , Impressão Tridimensional
20.
Materials (Basel) ; 16(10)2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37241487

RESUMO

In this study, metal 3D printing technology was used to create lattice-shaped test specimens of orthopedic implants to determine the effect of different lattice shapes on bone ingrowth. Six different lattice shapes were used: gyroid, cube, cylinder, tetrahedron, double pyramid, and Voronoi. The lattice-structured implants were produced from Ti6Al4V alloy using direct metal laser sintering 3D printing technology with an EOS M290 printer. The implants were implanted into the femoral condyles of sheep, and the animals were euthanized 8 and 12 weeks after surgery. To determine the degree of bone ingrowth for different lattice-shaped implants, mechanical, histological, and image processing tests on ground samples and optical microscopic images were performed. In the mechanical test, the force required to compress the different lattice-shaped implants and the force required for a solid implant were compared, and significant differences were found in several instances. Statistically evaluating the results of our image processing algorithm, it was found that the digitally segmented areas clearly consisted of ingrown bone tissue; this finding is also supported by the results of classical histological processing. Our main goal was realized, so the bone ingrowth efficiencies of the six lattice shapes were ranked. It was found that the gyroid, double pyramid, and cube-shaped lattice implants had the highest degree of bone tissue growth per unit time. This ranking of the three lattice shapes remained the same at both 8 and 12 weeks after euthanasia. In accordance with the study, as a side project, a new image processing algorithm was developed that proved suitable for determining the degree of bone ingrowth in lattice implants from optical microscopic images. Along with the cube lattice shape, whose high bone ingrowth values have been previously reported in many studies, it was found that the gyroid and double pyramid lattice shapes produced similarly good results.

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