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1.
Neurobiol Learn Mem ; 207: 107869, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38042330

RESUMO

The orbitofrontal cortex (OFC) is often proposed to function as a value integrator; however, alternative accounts focus on its role in representing associative structures that specify the probability and sensory identity of future outcomes. These two accounts make different predictions about how this area should respond to conditioned inhibitors of reward, since in the former, neural activity should reflect the negative value of the inhibitor, whereas in the latter, it should track the estimated probability of a future reward based on all cues present. Here, we assessed these predictions by recording from small groups of neurons in the lateral OFC of rats during training in a conditioned inhibition design. Rats showed negative summation when the inhibitor was compounded with a novel excitor, suggesting that they learned to respond to the conditioned inhibitor appropriately. Against this backdrop, we found unit and population responses that scaled with expected reward value on excitor + inhibitor compound trials. However, the responses of these neurons did not differentiate between the conditioned inhibitor and a neutral cue when both were presented in isolation. Further, when the ensemble patterns were analyzed, activity to the conditioned inhibitor did not classify according to putative negative value. Instead, it classified with a same-modality neutral cue when presented alone and as a unique item when presented in compound with a novel excitor. This pattern of results supports the notion that OFC encodes a model of the causal structure of the environment rather than either the modality or the value of cues.


Assuntos
Condicionamento Clássico , Neurônios , Ratos , Animais , Neurônios/fisiologia , Condicionamento Clássico/fisiologia , Córtex Pré-Frontal/fisiologia , Aprendizagem , Recompensa , Sinais (Psicologia)
2.
Phys Chem Chem Phys ; 26(36): 23663-23676, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39224043

RESUMO

Low-dimensional carbon materials are of great interest and have tremendous potential for application in flexible plastic electronics. However, the development of devices based on carbon structural hybrids is often hindered due to the high recombination rate of photoexcited charges, low absorbance, and other factors. This work discusses the emergence of multi-component structural forms of carbon from single-wall carbon nanotubes (SWCNTs) and demonstrates the electrical nature of the film containing these heterogeneous low-dimensional structural derivatives that are amalgamated in a polyurethane matrix. SWCNTs serve as a building block to give rise to multi-structural compounds, including multi-wall carbon nanotubes (MWCNTs), graphene sheets (GSs), carbon nanoscrolls (CNS), 'Y' and 'T' junctions, twisted CNTs and carbon nano-onion (CNO)-like structures, after performing oxidative purification and covalent functionalization processes. These one- and two-dimensional (1D and 2D) components with different individual electrical characteristics when integrated in a polyurethane binder and spin-coated on a SiO2/Si substrate exhibit an overall semiconducting behaviour. Current (I)-voltage (V) characteristics reveal thermally driven photo-excited charges that are mainly responsible for the observed current trend of the film. Herein, we explore a facile cost-effective strategy to fabricate stable thin film coatings comprising a random network of functionalized structural derivatives of carbon and polymer conjugates and investigate the overall electrical nature to envisage incorporating these nanomaterials in future plastic electronics.

3.
Phys Chem Chem Phys ; 23(48): 27437-27448, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34860230

RESUMO

Carbon nanoscrolls (CNS), a one dimensional (1D) helical form of carbon, have received enormous attention recently due to their unique structure, superior properties and potential applications. In this work, radial merging of HiPCO single walled nanotube (SWNT) bundles and emergence of CNS are reported following a reflux action involving wet oxidation, HCl washing and annealing at 900 °C. We observe macroscopic quantities of graphene sheets (GS) in the post-treated sample and beautiful manifestation of curling and folding of the GS into CNS. Here, a simple solution based oxidative route for successful merging and exfoliation of SWNT bundles and subsequent formation of CNS are demonstrated and discussed in view of Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) studies. Direct evidence of emergence of CNS from SWNTs via synthesis of GS through a simple oxidative method is reported for the first time.

4.
J Food Sci Technol ; 58(12): 4465-4477, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34629510

RESUMO

In this current scenario with changing food habits, escalating population and unrestricted use of natural resources, there are lacking of resources to provide nutritious food to all. Natural plant resources are fast depleting and need to explore new alternatives. Besides the staple rice and wheat; lots of underutilized crops are being consumed that are having great potential to replace the staple crops. Millets are one of the major underutilized crops with a Nutri-cereal potential. Millets are highly nutritive, non-acid-forming, gluten-free and having dietary properties. Despite the fact that millets are highly nutritious, their consumption is still limited to the conventional and poor population due to lack of awareness towards its nutritional values. There is lack of processing technologies, lack of food subsidies and inconvenience in food preparations which makes millets more obsolete. Millets are Nutri-cereals and rich in carbohydrates, dietary fibres, energy, essential fatty acids, proteins, vitamin-B and minerals such as calcium, iron, magnesium, potassium and zinc, which helps to prevent from post-translational diseases like, diabetes, cancer, cardiovascular and celiac diseases, etc. Millets help in controlling blood pressure, blood sugar level and thyroid but inspite of these functional properties, millets consumption is still declining. Millets utilization in-combination with other staple food crops to develop food alternatives has become an emerging area for food industries. Besides, to strengthen our fight against malnutrition in children and adolescents, consumption of millets can help to foster immunity and health. Here, author's have reviewed the potential of millets for their Nutri-cereal qualities.

5.
ACS Omega ; 6(37): 23826-23836, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34568662

RESUMO

We investigate here the strain-induced growth of Cu at 600 °C and its interactions with a thermally grown, 270 nm-thick SiO2 layer on the Si(111) substrate. Our results show clear evidence of triangular voids and formation of triangular islands on the surface via a void-filling mechanism upon Cu deposition, even on a 270 nm-thick dielectric. Different coordination states, oxidation numbers, and chemical compositions of the Cu-grown film are estimated from the core level X-ray photoelectron spectroscopy (XPS) measurements. We find evidence of different compound phases including an intermediate mixed-state of Cu-O-Si at the interface. Emergence of a mixed Cu-O-Si intermediate state is attributed to the new chemical states of Cu x+, O x , and Si x+ observed in the high-resolution XPS spectra. This intermediate state, which is supposed to be highly catalytic, is found in the sample with a concentration as high as ∼41%. Within the Cu-O-Si phase, the atomic percentages of Cu, O, and Si are ∼1, ∼86, and ∼13%, respectively. The electrical measurements carried out on the sample reveal different resistive channels across the film and an overall n-type semiconducting nature with a sheet resistance of the order of 106 Ω.

6.
Nanoscale Adv ; 3(11): 3184-3198, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36133669

RESUMO

Research on carbon material-based thin films with low light reflectance has received significant attention for the development of high absorber coatings for stray light control applications. Herein, we report a method for the successful fabrication of stable thin films comprised of carbon nanotubes (CNTs) and nanoscrolls (CNS) on an aluminium (Al) substrate, which exhibited low reflectance of the order of 2-3% in the visible and near-infrared (NIR) spectral bands. Changes in the structural and chemical composition of pristine single-walled carbon nanotube (SWCNT) samples were analyzed after each processing step. Spectroscopy, microscopy and microstructural studies demonstrated emergence of CNS and multi-walled carbon nanotubes (MWCNTs) due to the sequential chemical processing of the sample. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) studies revealed the formation of CNS via curling and folding of graphene sheets. Microstructural investigations including SEM and atomic force microscopy (AFM) confirmed the presence of microcavities and pores on the surface of the film. These cavities and pores significantly contribute to the observed low reflectance value of CNTs, CNS compound films by trapping the incident light. Fundamental space environmental simulation tests (SEST) were performed on the coated films, that showed promising results with reflectance values almost unaltered in the visible and NIR spectral bands, demonstrating the durability of these films as potential candidates to be used in extreme space environmental conditions. This study describes the preparation, characterization, and testing of blended CNT and CNS coatings for low-light scattering applications.

7.
J Hazard Mater ; 328: 117-126, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-28103487

RESUMO

Carbon quantum dots (CQDs) have emerged out as promising fluorescent probes for hazardous heavy metals detection in recent past. In this study, water soluble CQDs were synthesized by facile microwave pyrolysis of citric acid & cysteamine, and functionalized with ditheritheritol to impart thiol functionalities at surface for selective detection of toxic arsenite in water. Microscopic analysis reveals that the synthesized CQDs are of uniform size (diameter ∼5nm) and confirmed to have surface SH groups by FT-IR. The functionalized probe is then demonstrated for arsenite detection in water by "Turn-On" read out mechanism, which reduces the possibility of false positive signals associated with "turn off' probes reported earlier. The blue luminescent functionalized CQDs exhibit increase in fluorescence intensity on arsenite addition in 5-100ppb wide detection range. The probe can be used for sensitive detection of arsenite in environmental water to a theoretical detection limit (3s) of 0.086ppb (R2=0.9547) with good reproducibility at 2.6% relative standard deviation. The presented reliable, sensitive, rapid fCQDs probe demonstrated to exhibit high selectivity towards arsenite and exemplified for real water samples as well. The analytical performance of the presented probe is comparable to existing organic & semiconductor based optical probes.

8.
J Environ Biol ; 26(2): 197-204, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16161973

RESUMO

Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.


Assuntos
Cromo/toxicidade , Raphanus/efeitos dos fármacos , Curtume , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/toxicidade , Amilases/metabolismo , Biomassa , Catalase/metabolismo , Clorofila/metabolismo , Clorofila A , Germinação/efeitos dos fármacos , Resíduos Industriais , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raphanus/crescimento & desenvolvimento , Raphanus/metabolismo , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , alfa-Amilases/metabolismo , beta-Amilase/metabolismo
9.
Front Neurol ; 6: 69, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25883586

RESUMO

Sports-related concussions are particularly common during adolescence, a time when even mild brain injuries may disrupt ongoing brain maturation and result in long-term complications. A recent focus on the consequences of repetitive concussions among professional athletes has prompted the development of several new experimental models in rodents, as well as the revision of guidelines for best management of sports concussions. Here, we consider the utility of rodent models to understand the functional consequences and pathobiology of concussions in the developing brain, identifying the unique behavioral and pathological signatures of concussive brain injuries. The impact of repetitive concussions on behavioral consequences and injury progression is also addressed. In particular, we focus on the epidemiological, clinical, and experimental evidence underlying current recommendations for physical and cognitive rest after concussion, and highlight key areas in which further research is needed. Lastly, we consider how best to promote recovery after injury, recognizing that optimally timed, activity-based rehabilitative strategies may hold promise for the adolescent athlete who has sustained single or repetitive concussions. The purpose of this review is to inform the clinical research community as it strives to develop and optimize evidence-based guidelines for the concussed adolescent, in terms of both acute and long-term management.

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