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1.
J Neurooncol ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38960965

RESUMO

BACKGROUND: Quantifying tumor growth and treatment response noninvasively poses a challenge to all experimental tumor models. The aim of our study was, to assess the value of quantitative and visual examination and radiomic feature analysis of high-resolution MR images of heterotopic glioblastoma xenografts in mice to determine tumor cell proliferation (TCP). METHODS: Human glioblastoma cells were injected subcutaneously into both flanks of immunodeficient mice and followed up on a 3 T MR scanner. Volumes and signal intensities were calculated. Visual assessment of the internal tumor structure was based on a scoring system. Radiomic feature analysis was performed using MaZda software. The results were correlated with histopathology and immunochemistry. RESULTS: 21 tumors in 14 animals were analyzed. The volumes of xenografts with high TCP (H-TCP) increased, whereas those with low TCP (L-TCP) or no TCP (N-TCP) continued to decrease over time (p < 0.05). A low intensity rim (rim sign) on unenhanced T1-weighted images provided the highest diagnostic accuracy at visual analysis for assessing H-TCP (p < 0.05). Applying radiomic feature analysis, wavelet transform parameters were best for distinguishing between H-TCP and L-TCP / N-TCP (p < 0.05). CONCLUSION: Visual and radiomic feature analysis of the internal structure of heterotopically implanted glioblastomas provide reproducible and quantifiable results to predict the success of transplantation.

2.
BMC Med Educ ; 24(1): 541, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750528

RESUMO

BACKGROUND: Previous research indicates that reflection can foster medical communication competence. However, best practices for embedding reflection in online medical education are missing. This study examined how reflection processes can be promoted and embedded in an e-learning course on physician-patient communication to foster learning. METHODS: We investigated three differently designed e-learning conditions featuring different proportions of reflection triggers and compared their effects on students' reflections. We had 114 medical students in their first clinical year complete one of the variants: video modelling (VM, n = 39), video reflection (VR, n = 39), or a variant merging both approaches (VMR, n = 36). Each student wrote a total of nine reflections based on the same guiding questions at three time points embedded in the course. The students' levels of reflection were measured using an adapted version of the REFLECT rubric (scale 0-18). RESULTS: Students of all course variants achieved good levels of reflection beyond the descriptive level at all three time points, with no significant differences between the variants. The mean reflection scores at the end of the course were M = 14.22 for VM (SD = 2.23), M = 13.56 for VR (SD = 2.48), and M = 13.24 for VMR (SD = 2.21). Students who completed VM showed significantly improved levels of reflection over the course, whereas we found no statistically significant development for those in VR or VMR. The reflection scores correlated significantly positively with each other, as did the text lengths of the written reflections. Reflection scores also correlated significantly positively with text length. CONCLUSIONS: Our study offers a teaching strategy that can foster good levels of reflection, as demonstrated in the three e-learning variants. The developed reflection prompts can be easily embedded in various e-learning environments and enable reflections of good quality, even in settings with limited available teaching time.


Assuntos
Comunicação , Estudantes de Medicina , Humanos , Estudantes de Medicina/psicologia , Feminino , Educação de Graduação em Medicina/métodos , Masculino , Educação a Distância , Relações Médico-Paciente , Instrução por Computador/métodos , Competência Clínica , Gravação em Vídeo , Adulto Jovem , Adulto , Currículo
3.
J Eur Acad Dermatol Venereol ; 37(1): 160-165, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36097258

RESUMO

BACKGROUND: Scabies is an itchy, parasitic infection of the skin. Recent reports indicate there is a decreasing efficacy of the standard treatment of choice, topical 5% permethrin cream. OBJECTIVE: To evaluate the comparative efficacy, safety and tolerability of topical benzyl benzoate (BB) with oral ivermectin in the treatment of scabies. METHODS: Patients with dermoscopy-verified scabies visiting the dermatologic outpatient clinic were assessed for enrolment in the study. In total, 224 patients were enrolled and sequentially randomized into two equally sized groups. Group A received topical 25% or 10% BB for the daily use over a period of three consecutive days, group B received oral ivermectin (200 µg/kg body weight) twice, 1 week apart. Treatment outcome was evaluated by dermoscopy at a 3-week follow-up visit. RESULTS: Treatment resulted in a cure rate of 87% in group A and 86% in group B. After initial therapy failure in group A, six out of eight patients showed treatment response upon repeated application of BB, five of five when retreated with ivermectin and two of two with BB plus ivermectin, respectively. In group B, successful retreatment was observed in three out of three patients with ivermectin, two of two patients with BB and 11 of 11 patients with the combination of BB plus ivermectin, respectively. Tolerability and safety profile of oral ivermectin was excellent, while BB produced short burning sensations in 14%. CONCLUSION: Topical BB and oral ivermectin have shown comparable good therapeutic efficacy. Therefore, both agents constitute an adequate first-line therapy in the treatment of scabies. A combination of both agents may be considered in recalcitrant and extensively infested cases, additionally to crusted scabies.


Assuntos
Inseticidas , Escabiose , Humanos , Escabiose/tratamento farmacológico , Ivermectina/efeitos adversos , Permetrina , Benzoatos/uso terapêutico , Administração Oral , Inseticidas/uso terapêutico
4.
J Nat Prod ; 83(4): 834-842, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-32196341

RESUMO

Thymoquinone was recently reported as having a unique pencil-like odor and being the impact compound for the cedar-like and cedar wood-based product smell such as pencils. The compounds thymol and carvacrol are structurally related odorants commonly found in plants and foods such as thyme and oregano, also having a significant contribution to their overall aroma. However, a systematic elucidation of the sensory properties in this class of oxygenated, aromatic monoterpenoids has not been carried out. To close this gap and gain new insights into structure-odor relationships leading to pencil-like and woody odors, 19 structurally related derivatives of p-cymene starting from thymol and carvacrol were synthesized and characterized. The compounds had odor thresholds ranging from 2.0 ng/L air to 388.8 ng/L air, being lowest for thymol and carvacrol and highest for thymohydroquinone. The compounds smelled mostly thyme-like, oregano-like, and pencil-like with phenolic, earthy, and medicinal variations in their odor character, which could be successfully linked to structural motifs.


Assuntos
Cimenos/química , Monoterpenos/química , Monoterpenos/farmacologia , Odorantes/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Hidrocarbonetos Aromáticos/química , Estrutura Molecular , Monoterpenos/síntese química , Oxigênio/química , Limiar Sensorial/efeitos dos fármacos , Relação Estrutura-Atividade
5.
Childs Nerv Syst ; 36(5): 1067-1070, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31784819

RESUMO

Traumatic brain injury is common in children and can lead to death or considerable, long-lasting morbidity. We present the case of a 10-month-old female child who presented after being attacked by a cockerel in a chicken coop. Following a seizure, an MRI scan revealed an intracerebral haemorrhage underlying a stab-type wound inflicted by the bird. Animal bite injuries are common worldwide but they rarely cause intracranial injuries. Domestic hens are rarely dangerous but can become defensive or aggressive during breeding periods or when protecting their territory. To date, only a handful of articles have reported on wounds inflicted by chicken beaks. Those reported were largely facial or ocular injuries. Infectious complications have also been encountered post-injury. This is to our knowledge the first report of a bird attack resulting in significant penetrating traumatic brain injury. Children should be cautioned by guardians to avoid unsupervised contact with chickens, particularly during breeding. Attacks to the neurocranium when they occur must be taken seriously and not treated as humorous or insignificant. Imaging appropriate to the child's clinical condition should be pursued and appropriate intervention and antibiotic treatment should be implemented.


Assuntos
Lesões Encefálicas Traumáticas , Traumatismos Cranianos Penetrantes , Ferimentos Perfurantes , Animais , Galinhas , Feminino , Traumatismos Cranianos Penetrantes/complicações , Traumatismos Cranianos Penetrantes/diagnóstico por imagem , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino
6.
Telecomm Policy ; 44(6): 101988, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32377031

RESUMO

The field of artificial intelligence (AI) is experiencing a period of intense progress due to the consolidation of several key technological enablers. AI is already deployed widely and has a high impact on work and daily life activities. The continuation of this process will likely contribute to deep economic and social changes. To realise the tremendous benefits of AI while mitigating undesirable effects will require enlightened responses by many stakeholders. Varying national institutional, economic, political, and cultural conditions will influence how AI will affect convenience, efficiency, personalisation, privacy protection, and surveillance of citizens. Many expect that the winners of the AI development race will dominate the coming decades economically and geopolitically, potentially exacerbating tensions between countries. Moreover, nations are under pressure to protect their citizens and their interests-and even their own political stability-in the face of possible malicious or biased uses of AI. On the one hand, these different stressors and emphases in AI development and deployment among nations risk a fragmentation between world regions that threatens technology evolution and collaboration. On the other hand, some level of differentiation will likely enrich the global AI ecosystem in ways that stimulate innovation and introduce competitive checks and balances through the decentralisation of AI development. International cooperation, typically orchestrated by intergovernmental and non-governmental organisations, private sector initiatives, and by academic researchers, has improved common welfare and avoided undesirable outcomes in other technology areas. Because AI will most likely have more fundamental effects on our lives than other recent technologies, stronger forms of cooperation that address broader policy and governance challenges in addition to regulatory and technological issues may be needed. At a time of great challenges among nations, international policy coordination remains a necessary instrument to tackle the ethical, cultural, economic, and political repercussions of AI. We propose to advance the emerging concept of technology diplomacy to facilitate the global alignment of AI policy and governance and create a vibrant AI innovation system. We argue that the prevention of malicious uses of AI and the enhancement of human welfare create strong common interests across jurisdictions that require sustained efforts to develop better, mutually beneficial approaches. We hope that new technology diplomacy will facilitate the dialogues necessary to help all interested parties develop a shared understanding and coordinate efforts to utilise AI for the benefit of humanity, a task whose difficulty should not be underestimated.

7.
J Dtsch Dermatol Ges ; 21(5): 567-568, 2023 05.
Artigo em Alemão | MEDLINE | ID: mdl-37183742
8.
Chemistry ; 22(16): 5767-77, 2016 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-26990446

RESUMO

The streamlined catalytic access to enantiopure allylic amines as valuable precursors towards chiral ß- and γ-aminoalcohols as well as α- and ß-aminoacids is desirable for industrial purposes. In this article an enantioselective method is described that transforms achiral allylic alcohols and N-tosylisocyanate in a single step into highly enantioenriched N-tosyl protected allylic amines via an allylic carbamate intermediate. The latter is likely to undergo a cyclisation-induced [3,3]-rearrangement catalysed by a planar chiral pentaphenylferrocene palladacycle in cooperation with a tertiary amine base. The otherwise often indispensable activation of palladacycle catalysts by a silver salt is not required in the present case and there is also no need for an inert gas atmosphere. To further improve the synthetic value, the rearrangement was used to form dimethylaminosulfonyl-protected allylic amines, which can be deprotected under non-reductive conditions.


Assuntos
Aminas/química , Aminoácidos/química , Carbamatos/química , Paládio/química , Catálise , Estrutura Molecular , Nitrilas/química , Estereoisomerismo , Compostos de Tosil/química
9.
Org Biomol Chem ; 13(35): 9194-205, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26177934

RESUMO

Adenovirus type 37 (Ad37) is one of the principal agents responsible for epidemic keratoconjunctivitis (EKC), a severe ocular infection that remains without any available treatment. Recently, a trivalent sialic acid derivative (ME0322, Angew. Chem. Int. Ed., 2011, 50, 6519) was shown to function as a highly potent inhibitor of Ad37, efficiently preventing the attachment of the virion to the host cells and subsequent infection. Here, new trivalent sialic acid derivatives were designed, synthesized and their inhibitory properties against Ad37 infection of the human corneal epithelial cells were investigated. In comparison to ME0322, the best compound (17a) was found to be over three orders of magnitude more potent in a cell-attachment assay (IC50 = 1.4 nM) and about 140 times more potent in a cell-infection assay (IC50 = 2.9 nM). X-ray crystallographic analysis demonstrated a trivalent binding mode of all compounds to the Ad37 fiber knob. For the most potent compound ophthalmic toxicity in rabbits was investigated and it was concluded that repeated eye administration did not cause any adverse effects.


Assuntos
Adenoviridae/efeitos dos fármacos , Adenoviridae/fisiologia , Córnea/citologia , Células Epiteliais/virologia , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/farmacologia , Triazóis/química , Animais , Antivirais/síntese química , Antivirais/química , Antivirais/farmacologia , Química Click , Desenho de Fármacos , Células Epiteliais/efeitos dos fármacos , Humanos , Masculino , Modelos Moleculares , Conformação Molecular , Ácido N-Acetilneuramínico/análogos & derivados , Ácido N-Acetilneuramínico/síntese química , Coelhos
10.
J Am Acad Dermatol ; 83(4): 1222-1224, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32682031
11.
Circ Res ; 111(6): 675-84, 2012 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-22811559

RESUMO

RATIONALE: Autoantibodies directed against the second extracellular loop of the cardiac ß1-adrenergic receptor (ß1-AR) are thought to contribute to the pathogenesis of dilated cardiomyopathy (DCM) and Chagas heart disease. Various approaches have been used to detect such autoantibodies; however, the reported prevalence varies largely, depending on the detection method used. OBJECTIVE: We analyzed sera from 167 DCM patients (ejection fraction<45%) and from 110 age-matched volunteers who did not report any heart disease themselves, with an often used simple peptide-ELISA approach, and compared it with a novel whole cell-based ELISA, using cells expressing the full transgene for the human ß1-AR. Additionally, 35 patients with hypertensive heart disease with preserved ejection fraction were investigated. METHODS AND RESULTS: The novel assay was designed according to the currently most reliable anti-TSH receptor antibody-ELISA used to diagnose Graves disease ("third-generation assay") and also detects the target antibodies by competition with a specific monoclonal anti-ß1-AR antibody (ß1-AR MAb) directed against the functionally relevant ß1-AR epitope. Anti-ß1-AR antibodies were detected in ≈60% of DCM patients and in ≈8% of healthy volunteers using the same cutoff values. The prevalence of these antibodies was 17% in patients with hypertensive heart disease. Anti-ß1-AR antibody titers (defined as inhibition of ß1-AR MAb-binding) were no longer detected after depleting sera from IgG antibodies by protein G adsorption. In contrast, a previously used ELISA conducted with a linear 26-meric peptide derived from the second extracellular ß1-AR loop yielded a high number of false-positive results precluding any specific identification of DCM patients. CONCLUSIONS: We established a simple and efficient screening assay detecting disease-relevant ß1-AR autoantibodies in patient sera yielding a high reproducibility also in high throughput screening. The assay was validated according to "good laboratory practice" and can serve as a companion biodiagnostic assay for the development and evaluation of antibody-directed therapies in antibody-positive heart failure.


Assuntos
Autoanticorpos/imunologia , Cardiomiopatia Dilatada/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Receptores Adrenérgicos beta 1/imunologia , Animais , Anticorpos Monoclonais/imunologia , Afinidade de Anticorpos/imunologia , Especificidade de Anticorpos/imunologia , Autoanticorpos/sangue , Sequência de Bases , Cardiomiopatia Dilatada/sangue , Cardiomiopatia Dilatada/diagnóstico , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Receptores Adrenérgicos beta 1/genética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Células Sf9 , Transfecção
12.
Angew Chem Int Ed Engl ; 53(29): 7634-8, 2014 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-24898109

RESUMO

A regio- and enantioselective tandem reaction is reported capable of directly transforming readily accessible achiral allylic alcohols into chiral sulfonyl-protected allylic amines. The reaction is catalyzed by the cooperative action of a chiral ferrocene palladacycle and a tertiary amine base and combines high step-economy with operational simplicity (e.g. no need for inert-gas atmosphere or catalyst activation). Mechanistic studies support a Pd(II)-catalyzed [3,3] rearrangement of allylic carbamates--generated in situ from the allylic alcohol and an isocyanate--as the key step, which is followed by a decarboxylation.

13.
Br J Educ Psychol ; 94(1): 216-230, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37941506

RESUMO

BACKGROUND: Despite the growing emphasis on research-based teacher education and calls for evidence-informed practice, teachers tend to prefer experiential over scientific knowledge sources to inform their actions, justify decisions and analyse educational problems. This tendency already occurs as early as during initial teacher education, and it is possibly bolstered by school internships where mentors emphasise the value of practical over scientific knowledge. AIMS: The present study applied the theory of planned behaviour (TPB) to investigate under what conditions pre-service teachers intend to use and prefer scientific sources from educational research. METHODS: The study's participants were 343 pre-service teachers in a half-year school internship who indicated their attitudes towards educational research, behavioural control (i.e. self-efficacy), perceived subjective norm, intentions of using research and preference for scientific sources in a survey. Perceived subjective norm was established by measuring whether pre-service teachers believed their mentors considered research-based knowledge. RESULTS: In line with the predictions of the standard TPB model, structural equation modelling confirmed the effects of positive attitudes, self-efficacy and perceived subjective norm on pre-service teachers' intentions of using research. In turn, intentions and self-efficacy predicted preferences for scientific sources but not the use of scientific sources when planning a lesson in the internship. CONCLUSIONS: Pre-service teachers' scientific source preferences are shaped not only by personal dispositions but also by the social context of school.


Assuntos
Pessoal de Educação , Teoria do Comportamento Planejado , Humanos , Intenção , Instituições Acadêmicas , Atitude , Professores Escolares
14.
Cancers (Basel) ; 16(8)2024 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-38672673

RESUMO

BACKGROUND: This study aimed to investigate the effects of tetrahydrolipstatin (orlistat) on heterotopic glioblastoma in mice by applying MRI and correlating the results with histopathology and immunochemistry. METHODS: Human glioblastoma cells were injected subcutaneously into the groins of immunodeficient mice. After tumor growth of >150 mm3, the animals were assigned into a treatment group (n = 6), which received daily intraperitoneal injections of orlistat, and a control group (n = 7). MRI was performed at the time of randomization and before euthanizing the animals. Tumor volumes were calculated, and signal intensities were analyzed. The internal tumor structure was evaluated visually and with texture analysis. Western blotting and protein expression analysis were performed. RESULTS: At histology, all tumors showed high mitotic and proliferative activity (Ki67 ≥ 10%). Reduced fatty acid synthetase expression was measured in the orlistat group (p < 0.05). Based on the results of morphologic MRI-based analysis, tumor growth remained concentric in the control group and changed to eccentric in the treatment group (p < 0.05). The largest area under the receiver operating curve of the predictors derived from the texture analysis of T2w images was for wavelet transform parameters WavEnHL_s3 and WavEnLH_s4 at 0.96 and 1.00, respectively. CONCLUSIONS: Orlistat showed effects on heterotopically implanted glioblastoma multiforme in MRI studies of mice based on morphologic and texture analysis.

15.
Patient Educ Couns ; 121: 108132, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38184987

RESUMO

OBJECTIVE: The present study investigated the efficacy of the didactic approaches of video modeling (VM, best-practice examples), video reflection (VR, problem-based approach), and the combination of both (VMR) in fostering medical communication competence in a video-based digital learning environment. METHODS: N = 126 third-year medical students who participated in the pre-post study were assigned to either the intervention groups (VM, VR, and VMR) or the wait-list control group. The efficacy of the three approaches was assessed by means of a situational judgment test (SJT) of medical communication competence. To investigate the differences between the wait-list control and the intervention groups (H1), between the single-mode and combined conditions (H2), and between VM and VR (H3), we applied planned contrast analyses. RESULTS: The planned contrasts showed that the VR condition significantly improved learning outcomes in comparison to the VM condition (H3). The decreased mean scores of the VM condition offset the increased mean scores of VR, and thus no significant differences could be found in H1 and H2. CONCLUSIONS: Our study provides promising evidence that VR fosters medical communication competence more effectively than VM. PRACTICAL IMPLICATIONS: Medical students' learning in video-based digital environments can be facilitated by the use of interactive VR.


Assuntos
Instrução por Computador , Estudantes de Medicina , Humanos , Competência Clínica , Aprendizagem , Comunicação
16.
Redox Biol ; 73: 103165, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38688061

RESUMO

The activation of ferroptosis is being pursued in cancer research as a strategy to target apoptosis-resistant cells. By contrast, in various diseases that affect the cardiovascular system, kidneys, liver, and central and peripheral nervous systems, attention is directed toward interventions that prevent ferroptotic cell death. Mechanistic insights into both research areas stem largely from studies using cellular in vitro models. However, intervention strategies that show promise in cellular test systems often fail in clinical trials, which raises concerns regarding the predictive validity of the utilized in vitro models. In this study, the human LUHMES cell line, which serves as a model for human dopaminergic neurons, was used to characterize factors influencing the activation of ferroptosis. Erastin and RSL-3 induced cell death that was distinct from apoptosis. Parameters such as the differentiation state of LUHMES cells, cell density, and the number and timing of medium changes were identified as determinants of sensitivity to ferroptosis activation. In differentiated LUHMES cells, interventions at mechanistically divergent sites (iron chelation, coenzyme Q10, peroxidase mimics, or inhibition of 12/15-lipoxygenase) provide almost complete protection from ferroptosis. LUHMES cells allowed the experimental modulation of intracellular iron concentrations and demonstrated a correlation between intracellular iron levels, the rate of lipid peroxidation, as well as the sensitivity of the cells to ferroptotic cell death. These findings underscore the importance of understanding the various factors that influence ferroptosis activation and highlight the need for well-characterized in vitro models to enhance the reliability and predictive value of observations in ferroptosis research, particularly when translating findings into in vivo contexts.


Assuntos
Neurônios Dopaminérgicos , Ferroptose , Humanos , Neurônios Dopaminérgicos/metabolismo , Linhagem Celular , Piperazinas/farmacologia , Ferro/metabolismo , Diferenciação Celular , Apoptose , Carbolinas , Ubiquinona/análogos & derivados
17.
Biochim Biophys Acta ; 1822(8): 1230-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22542511

RESUMO

The fruit fly Drosophila melanogaster is increasingly utilized as an alternative to costly rodent models to study human diseases. Fly models exist for a wide variety of human conditions, such as Alzheimer's and Parkinson's Disease, or cardiac function. Advantages of the fly system are its rapid generation time and its low cost. However, the greatest strength of the fly system are the powerful genetic tools that allow for rapid dissection of molecular disease mechanisms. Here, we describe the diet-dependent development of metabolic phenotypes in adult fruit flies. Depending on the specific type of nutrient, as well as its relative quantity in the diet, flies show weight gain and changes in the levels of storage macromolecules. Furthermore, the activity of insulin-signaling in the major metabolic organ of the fly, the fat body, decreases upon overfeeding. This decrease in insulin-signaling activity in overfed flies is moreover observed when flies are challenged with an acute food stimulus, suggesting that overfeeding leads to insulin resistance. Similar changes were observed in aging flies, with the development of the insulin resistance-like phenotype beginning at early middle ages. Taken together, these data demonstrate that imbalanced diet disrupts metabolic homeostasis in adult D. melanogaster and promotes insulin-resistant phenotypes. Therefore, the fly system may be a useful alternative tool in the investigation of molecular mechanisms of insulin resistance and the development of pharmacologic treatment options.


Assuntos
Drosophila melanogaster/metabolismo , Resistência à Insulina/fisiologia , Fatores Etários , Animais , Gorduras na Dieta/metabolismo , Proteínas Alimentares/metabolismo , Modelos Animais de Doenças , Insulina/metabolismo , Transdução de Sinais , Sacarose/metabolismo
18.
Phys Rev Lett ; 111(21): 215304, 2013 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-24313499

RESUMO

We propose a novel realization of Kondo physics with ultracold atomic gases. It is based on a Fermi sea of two different hyperfine states of one atom species forming bound states with a different species, which is spatially confined in a trapping potential. We show that different situations displaying Kondo physics can be realized when Feshbach resonances between the species are tuned by a magnetic field and the trapping frequency is varied. We illustrate that a mixture of 40K and 23Na atoms can be used to generate a Kondo-correlated state and that momentum resolved radio frequency spectroscopy can provide unambiguous signatures of the formation of Kondo resonances at the Fermi energy. We discuss how tools of atomic physics can be used to investigate open questions for Kondo physics, such as the extension of the Kondo screening cloud.

19.
Polymers (Basel) ; 15(9)2023 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-37177328

RESUMO

Recently, fiber-reinforced, epoxy-based, optically transparent composites were successfully produced using resin transfer molding (RTM) techniques. Generally, the production of structural, optically transparent composites is challenging since it requires the combination of a very smooth mold surface with a sufficient control of resin flow that leads to no visible voids. Furthermore, it requires a minimum deviation of the refractive indices (RIs) of the matrix polymer and the reinforcement fibers. Here, a new mold design is described and three plates of optically transparent glass fiber-reinforced polymers (tGFRP) with reproducible properties as well as high fiber volume fractions were produced using the RTM process and in situ polymerization of an epoxy resin system enclosing E-glass fiber textiles. Their mechanical (flexural), microstructural (fiber volume fraction, surface roughness, etc.), thermal (DSC, TGA, etc.), and optical (dispersion curves of glass fibers and polymer as well as transmission over visible spectra curves of the tGFRP at varying tempering states) properties were evaluated. The research showed improved surface quality and good transmission data for samples manufactured by a new Optical-RTM setup compared to a standard RTM mold. The maximum transmission was reported to be ≈74%. In addition, no detectable voids were found in these samples. Furthermore, a flexural modulus of 23.49 ± 0.64 GPa was achieved for the Optical-RTM samples having a fiber volume fraction of ≈42%.

20.
Life Sci Alliance ; 5(8)2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35459736

RESUMO

Mitochondrial homeostasis is tightly controlled by ubiquitination. The mitochondrial integral membrane ubiquitin ligase MARCH5 is a crucial regulator of mitochondrial membrane fission, fusion, and disposal through mitophagy. In addition, the lipid composition of mitochondrial membranes can determine mitochondrial dynamics and organelle turnover. However, how lipids influence the ubiquitination processes that control mitochondrial homeostasis remains unknown. Here, we show that lipids common to the mitochondrial membranes interact with MARCH5 and affect its activity and stability depending on the lipid composition in vitro. As the only one of the tested lipids, cardiolipin binding to purified MARCH5 induces a significant decrease in thermal stability, whereas stabilisation increases the strongest in the presence of phosphatidic acid. Furthermore, we observe that the addition of lipids to purified MARCH5 alters the ubiquitination pattern. Specifically, cardiolipin enhances auto-ubiquitination of MARCH5. Our work shows that lipids can directly affect the activity of ubiquitin ligases and suggests that the lipid composition in mitochondrial membranes could control ubiquitination-dependent mechanisms that regulate the dynamics and turnover of mitochondria.


Assuntos
Membranas Mitocondriais , Proteínas Mitocondriais , Cardiolipinas/metabolismo , Proteínas de Membrana/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Fosfolipídeos/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
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