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1.
Nanotechnology ; 35(29)2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38636460

RESUMO

The tunability and controllability of conductance quantization mediated multilevel resistive switching (RS) memory devices, fabricated in crossbar geometry can be a promising alternative for boosting storage density. Here, we report fabrication of Cu/TiO2/Pt based RS devices in 8 × 8 crossbar geometry, which showed reliable bipolar RS operations. The crossbar devices showed excellent spatial and temporal variability, time retention and low switching voltage (<1 V) and current (∼100µA). Furthermore, during the reset switching, highly repeatable and reliable integral and half-integral quantized conductance (QC) was observed. The observed QC phenomenon was attributed to the two dimensional confinement of electrons as lateral width of the conducting filament (CF) matches the fermi wavelength. The magnitude and number of the QC steps were found to increase from ∼2.5 to 12.5 and from 5 to 18, respectively by increasing the compliance current (IC) from 50 to 800µA which also increased the diameter of the CF from ∼1.2 to 3.3 nm. The enhancement in both number and magnitude of QC states was explained using electrochemical dissolution mechanism of CF of varying diameter. A thicker CF, formed at higherIC, undergoes a gradual rupture during reset process yielding a greater number of QC steps compared to a thinner CF. The realisation of QC states in the crossbar Cu/TiO2/Pt device as well asICmediated tunability of their magnitude and number may find applications in high-density resistive memory storage devices and neuromorphic computing.

2.
Carbohydr Polym ; 346: 122575, 2024 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-39245478

RESUMO

Many neurodegenerative and psychiatric malignancies like Parkinson' disease (PD) originate from an imbalance of 17ß-Estradiol (E2) in the human brain. However, the peripheral side effects of the usage of E2 for PD therapy and less understanding of the molecular mechanism hinder establishing its neurotherapeutic potential. In the present work, systemic side effects were overcome by targeted delivery using Dopamine receptor D3 (DRD3) conjugated E2-loaded chitosan nanoparticles (Ab-ECSnps) that showed a promising delivery to the brain. E2 is a specific calpain inhibitor that fosters neurodegeneration by disrupting mitochondrial function, while B-cell-specific Moloney murine leukemia virus integration region 1 (BMI1), an epigenetic regulator, is crucial in preserving mitochondrial homeostasis. We showed the administration of Ab-ECSnps inhibits calpain's translocation into mitochondria while promoting the translocation of BMI1 to mitochondria, thereby conferring neurotherapeutic benefits by enhancing cell viability, increasing mitochondrial DNA copy number, and preserving mitochondrial membrane potential. Further, we showed a novel molecular mechanism of BMI1 regulation by calpain that might contribute to maintaining mitochondrial homeostasis for attenuating PD. Concomitantly, Ab-ECSnps showed neurotherapeutic potential in the in vivo PD model. We showed for the first time that our brain-specific targeted delivery might regulate calpain-mediated BMI1 expression, thereby preserving mitochondrial homeostasis to alleviate PD.


Assuntos
Calpaína , Quitosana , Mitocôndrias , Nanopartículas , Doença de Parkinson , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Calpaína/metabolismo , Calpaína/genética , Animais , Doença de Parkinson/tratamento farmacológico , Nanopartículas/química , Quitosana/química , Humanos , Camundongos , Epigênese Genética/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL
3.
Aquat Toxicol ; 202: 145-152, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30031254

RESUMO

Triclosan and its metabolites are detected in a diverse aquatic environment and are major concerns for various aquatic organisms. The present study investigated the impact of acute and sub-lethal exposure of triclosan on behaviour, activities of acetylcholinesterase and selected antioxidant enzymes, haematological and serum gas-electrolyte parameters of Pangasianodon hypophthalmus. The 96 h LC50 of triclosan for P. hypophthalmus was estimated as 1458 µg L-1. Further, sub-lethal triclosan exposure to 1/15th (97 µg L-1), 1/10th (145 µg L-1) and 1/5th (291 µg L-1) of 96 h LC50 concentration for a period of 45 days lead to decrease in total erythrocyte count, haemoglobin content and packed cell volume of blood while total leukocyte count increased significantly (p < 0.05) as compared to control. A concentration-dependent increase in the serum chloride and decrease in partial pressure of oxygen in blood serum was noted on 45th day. An increased activity of catalase and superoxide dismutase in gill and liver tissues and inhibition of acetylcholinesterase activity in brain was observed on 15th, 30th and 45th day of exposure which was dependent on both - concentration of triclosan and duration of exposure. A significant high activity of glutathione-S-transferase in gill and liver tissue was observed in triclosan exposed groups in comparison to control during the experimental period. The study shows that long-term sub-lethal exposure of triclosan to fish can lead to several physiological alterations such as enzymatic scavenging of oxygen radicals and the normal neurological functions mediated by the enzyme acetylcholinesterase. With increasing anthropogenic activity, the study provides a convincing evidence for the necessity of a regulated use and safer disposal of triclosan to the environment.


Assuntos
Antioxidantes/metabolismo , Comportamento Animal/efeitos dos fármacos , Triclosan/toxicidade , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Gasometria , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Catalase/metabolismo , Peixes-Gato/crescimento & desenvolvimento , Peixes-Gato/metabolismo , Cloretos/sangue , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Transferase/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Oxigênio/sangue , Superóxido Dismutase/metabolismo
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