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1.
Exp Brain Res ; 241(9): 2299-2309, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37584684

ABSTRACT

We estimate our hand's position by combining relevant visual and proprioceptive cues. A cross-sensory spatial mismatch can be created by viewing the hand through a prism or, more recently, rotating a visual cursor that represents hand position. This is often done in the context of target-directed reaching to study motor adaptation, the systematic updating of motor commands in response to a systematic movement error. However, a visuo-proprioceptive mismatch also elicits recalibration in the relationship between the hand's seen and felt position. The principles governing visuo-proprioceptive recalibration are poorly understood, compared to motor adaptation. For example, motor adaptation occurs robustly whether the cursor is rotated quickly or slowly, although the former may involve more explicit processes. Here, we asked whether visuo-proprioceptive recalibration, in the absence of motor adaptation, works the same way. Three groups experienced a 70 mm visuo-proprioceptive mismatch about their hand at a Slow, Medium, or Fast rate (0.84, 1.67, or 3.34 mm every two trials, respectively), with no error feedback. Once attained, the 70 mm mismatch was maintained for the remaining trials. Total recalibration differed significantly across groups, with the Fast, Medium, and Slow groups recalibrating 63.7, 56.3, and 42.8 mm on average, respectively. This suggests a slower mismatch rate may be less effective at eliciting recalibration. In contrast to motor adaptation studies, no further recalibration was observed in the maintenance phase. This may be related to the distinct mechanisms thought to contribute to perceptual recalibration via cross-sensory cue conflict versus sensory prediction errors.


Subject(s)
Feedback, Sensory , Psychomotor Performance , Humans , Psychomotor Performance/physiology , Feedback, Sensory/physiology , Proprioception/physiology , Hand/physiology , Adaptation, Physiological/physiology , Perception , Visual Perception/physiology
2.
Chemistry ; 29(61): e202302007, 2023 Nov 02.
Article in English | MEDLINE | ID: mdl-37486329

ABSTRACT

Sustainable chemical production requires fundamentally new types of catalysts and catalytic technologies. The development of coherent and robust catalytic systems based on earth-abundant transition metals is essential, but highly challenging. Herein, we systematically explored a general hydrogenative cleavage/N-alkylation tandem of cyclic and acyclic diazo (N=N) compounds to value-added amines under manganese catalysis. The reaction is catalyzed by a single-site molecular manganese complex and proceeds via tandem dehydrogenation, transfer hydrogenation, and borrowing hydrogenation strategies. Interestingly, the reaction involves abundantly available renewable feedstocks, such as alcohols, that can act as (transfer)hydrogenating and alkylating agents. The synthetic application of our approach in large-scale pharmaceutical synthesis and easy access to highly demanding N-CH3 /CD3 derivatives are also demonstrated. Kinetic studies show that the reaction rate depends on the concentration of alcohol and Mn-catalyst and follows fractional orders. Several selective bond activation/formation reactions occur sequentially via amine-amide metal-ligand cooperation.

3.
Sci Rep ; 13(1): 6097, 2023 04 13.
Article in English | MEDLINE | ID: mdl-37055541

ABSTRACT

The brain estimates hand position using visual and proprioceptive cues, which are combined to give an integrated multisensory estimate. Spatial mismatches between cues elicit recalibration, a compensatory process where each unimodal estimate is shifted closer to the other. It is unclear how well visuo-proprioceptive recalibration is retained after mismatch exposure. Here we asked whether direct vision and/or active movement of the hand can undo visuo-proprioceptive recalibration, and whether recalibration is still evident 24 h later. 75 participants performed two blocks of visual, proprioceptive, and combination trials, with no feedback or direct vision of the hand. In Block 1, a 70 mm visuo-proprioceptive mismatch was gradually imposed, and recalibration assessed. Block 2 tested retention. Between blocks, Groups 1-4 rested or made active movements with their directly visible or unseen hand for several minutes. Group 5 had a 24-h gap between blocks. All five groups recalibrated both vision and proprioception in Block 1, and Groups 1-4 retained most of this recalibration in Block 2. Interestingly, Group 5 showed an offline increase in proprioceptive recalibration, but retained little visual recalibration. Our results suggested that visuo-proprioceptive recalibration is robustly retained in the short-term. In the longer term, contextual factors may affect retention.


Subject(s)
Adaptation, Physiological , Psychomotor Performance , Humans , Feedback, Sensory , Proprioception , Hand , Visual Perception
4.
Nanotechnology ; 33(42)2022 Jul 28.
Article in English | MEDLINE | ID: mdl-35830844

ABSTRACT

Spinel Co3O4nanospheres have been synthesized by the microwave-assisted hydrothermal method. The N-doped graphene nanosheets (NGN) were synthesized using Hummer's method. The prepared spinel Co3O4and NGN were mixed under certain proportions using an ultrasonication process and treated with microwave radiation to prepare a novel spinel Co3O4nanospheres infused NGN. The synthesized samples were characterized by x-ray diffraction, Raman spectroscopy, Zetasizer, scanning electron microscope/transmission electron microscopy and x-ray photoelectron spectroscopy for identifying crystal structure and phase, particle size, and the morphology of the nanostructure and the elemental configuration, respectively. The prepared spinel Co3O4/NGN were used as anode material and lithium metal as a reference electrode to fabricate half cell using Swagelok cell components. The electrochemical properties were studied and found to exhibit a larger specific capacity of 575 mAh g-1compared to traditional graphite electrodes, after 100 cycles under 0.1 C rate with a coulombic efficiency of ≈100%. The good electrochemical properties ascribe to the distinctive surface morphological nanostructures of nanoporous nanospheres of spinel Co3O4nanospheres and nanosheets of N-doped graphene that reduce the lithium-ion diffusion pathway. The developed anode material would be a potential electrode for lithium ion battery applications.

5.
J Family Med Prim Care ; 11(10): 6581-6585, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36618249

ABSTRACT

The most common primary malignancies that affect the pericardium are lung cancers. Typically, pericardial involvement stays undiagnosed, with almost 1-20% of all tumor-related autopsies revealing invasion of the pericardium. Pericardial effusions are seldom the first location of metastasis and presentation of a primary malignancy. Malignant pericardial effusions are usually silent, although they cause dyspnea, chest discomfort, arrhythmias, cough, and, in rare cases, pericardial tamponade. In a patient with tamponade, a high index of tumor-related suspicion is crucial to rule out cancer. Emergency pericardiocentesis is indicated based on the clinical presentation, however, the patient frequently has a bad prognosis regardless of whether treatment is administered or not. In this case series, we report five cases of non-small cell lung cancer (NSCLC) with pericardial effusion as an initial presentation.

6.
J Org Chem ; 86(11): 7552-7562, 2021 Jun 04.
Article in English | MEDLINE | ID: mdl-34032425

ABSTRACT

The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C═C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.

7.
Org Lett ; 23(9): 3320-3325, 2021 May 07.
Article in English | MEDLINE | ID: mdl-33881325

ABSTRACT

Acceptorless double dehydrogenative cross-coupling of secondary and primary alcohols under nickel catalysis is reported. This Guerbet type reaction provides an atom- and a step-economical method for the C-alkylation of secondary alcohols under mild, benign conditions. A broad range of substrates including aromatic, cyclic, acyclic, and aliphatic alcohols was well tolerated. Interestingly, the C-alkylation of cholesterol derivatives and the double C-alkylation of cyclopentanol with various alcohols were also demonstrated.

8.
J Neurophysiol ; 124(3): 645-647, 2020 09 01.
Article in English | MEDLINE | ID: mdl-32727314

ABSTRACT

The sequence learning paradigm has been used extensively to study motor skill acquisition. Skilled movement involves combining smaller elements of the movement in a particular order with certain timing; in sequence learning these are typically button presses, but other motor skills may include more complex elements. This paper reviews recent evidence suggesting the sequence learning paradigm can be used to understand how the brain abstractly represents the ordering of discrete actions in a complex movement.


Subject(s)
Motor Activity/physiology , Motor Skills/physiology , Prefrontal Cortex/physiology , Serial Learning/physiology , Humans
9.
J Org Chem ; 85(15): 9876-9886, 2020 Aug 07.
Article in English | MEDLINE | ID: mdl-32600041

ABSTRACT

Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- and N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.

10.
ACS Omega ; 5(11): 6100-6112, 2020 Mar 24.
Article in English | MEDLINE | ID: mdl-32226893

ABSTRACT

This work reports the synthesis of nanosilica-coated magnetic carbonaceous adsorbents (MCA@SiO2) using low-temperature hydrothermal carbonization technique (HCT) and the feasibility to utilize it for methylene blue (MB) adsorption. Initially, a carbon precursor (CP) was synthesized from corn starch under saline conditions at 453 K via HCT followed by the magnetization of CP again via HCT at 453 K. Subsequently, MCA was coated with silica nanoparticles. MCA and MCA@SiO2 were characterized using X-ray diffraction, Fourier transform infrared, scanning electron microscopy/energy-dispersive spectroscopy, transmission electron microscopy, and Brunauer-Emmett-Teller (BET) N2 adsorption-desorption isotherms. The BET surface area of MCA and MCA@SiO2 were found to be 118 and 276 m2 g-1, respectively. Adsorption of MB onto MCA@SiO2 was performed using batch adsorption studies and in the optimum condition, MCA@SiO2 showed 99% adsorption efficiency with 0.5 g L-1 of MCA@SiO2 at pH 7. Adsorption isotherm studies predicted that MB adsorption onto MCA@SiO2 was homogeneous monolayer adsorption, which was best described using a Langmuir model with the maximum adsorption capacity of 516.9 mg g-1 at 25 °C. During adsorption kinetics, a rapid dye removal was observed which followed pseudo-first- as well as pseudo-second-order models, which suggested that MB dye molecules were adsorbed onto MCA@SiO2 via both ion exchange as well as the chemisorption process. The endothermic and spontaneous nature of the adsorption of MB onto MCA@SiO2 was established by thermodynamics studies. Mechanism of dye diffusion was collectively governed by intraparticle diffusion and film diffusion processes. Furthermore, MB was also selectively adsorbed from its mixture with an anionic dye, that is, methyl orange. Column adsorption studies showed that approximately 500 mL of MB having 50 mg L-1 concentration can be treated with 0.5 g L-1 of MCA@SiO2. Furthermore, MCA@SiO2 was repeatedly used for 20 cycles of adsorption-desorption of MB. Therefore, MCA@SiO2 can be effectively utilized in cationic dye-contaminated wastewater remediation applications.

11.
Int J Biol Macromol ; 143: 413-423, 2020 Jan 15.
Article in English | MEDLINE | ID: mdl-31778694

ABSTRACT

In this research work the superporous hydrogels (SPHs) of acrylic acid (AA) and acrylamide (AM) with gum xanthan (GX) were synthesized using glass blowing and foaming technique and tested the feasibility of synthesized SPHs to remove removal of methyl violet dye (MV) by the process of adsorption from aqueous solution. Swelling properties of synthesized SPHs with different concentrations of GX were studied in deionized water and the swelling kinetics followed first-order model. The adsorption of MV using SPHs was highly influenced by the solution pH. Adsorption kinetics followed non-linear pseudo-second-order rate equation, whereas, isotherm of adsorption followed monolayer Langmuir model. Diffusion mechanism of dye molecules was controlled by the combination of two mechanisms i.e. intraparticle and liquid film diffusion mechanisms. Furthermore, during desorption studies, SPHs were efficiently used for the five continuous adsorption-desorption cycles. Hence, the removal of cationic dyes could be done using SPHs of GX as effective adsorbents.


Subject(s)
Gentian Violet/chemistry , Polysaccharides, Bacterial/chemistry , Water Purification , Hydrogels/chemical synthesis , Hydrogels/chemistry , Porosity
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