Novel copolyhydrazides and copolyoxadiazoles based on 1,4-phenyl linkage and 1,3,4-thiadiazole moiety in the polymer Main chain to induce glass transition and to improve the thermal stability, solubility, and antimicrobial activity

Abstract

Polyhydrazides (PHs) and polyoxadiazoles (PODs) have broad potential applications, but PHs are generally not high-temperature resistant and PODs are commonly insoluble in organic solvents, degrade before melting, and do not show glass-transition temperature (T_g). These limitations make their processing quite difficult. To overcome these shortcomings, novel copolyhydrazides (CPHs) and copolyoxadiazoles (CPODs) based on 1,4-phenyl linkage and 1,3,4-thiadiazole moiety in the main chain have been synthesized. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed to assess the polymers thermal behavior. Also, the crystalline structure and surface morphology were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, their solubility, viscosity, UV-visible absorption, antimicrobial characteristics were studied. Most of the new CPHs and CPODs showed high thermal stability and good solubility in polar aprotic solvents. Moreover, the CPODs melted and showed T_g and fortunately their T_g values are still high (>227 °C), so they are suitable for use under extreme conditions. It seems that incorporating 1,4-phenyl linkage and 1,3,4-thiadiazole moiety into the polymer main chain enhanced the solubility and suppressed the crystallinity, while kept the thermal stability. Furthermore, the CPODs gave large antibacterial and antifungal activities, confirming the possibility to be used in medicinal fields.

Graphical abstract

Effects of bulky moieties on the polymer properties.

http://bit.ly/2TrsDXA

Unmasking neurobiological commonalities between addictive disorders and impulse control disorders in Parkinson’s disease

Abstract

Changes in reward circuitry have been studied extensively in substance and behavioural addictions. However, comparatively little is known about the neurobiology underlying impulse control disorders (ICDs) in Parkinson's disease, which show roughly similar risk factors and behavioural presentations to both stimulant and behavioural addictions. ICDs occur in a subset of susceptible patients with Parkinson's disease (PD) following intake of dopamine replacement therapy (DRT). These behavioural disorders often have debilitating effects on a patient's quality of life and increase caregiver burden. This comprehensive review examined findings of 40 neuroimaging studies of ICDs in PD to determine (a) whether there are putative neurobiological commonalities between traditional substance and behavioural addictions and DRT-induced ICD in PD and (b) opportunities for future studies to advance current neurobiological understanding of the phenomenon. Results revealed that strikingly similar (a) deficits in dopaminergic receptor expression, (b) connectivity changes in corticostriatal circuitry and (c) neural responses to cue exposure are observed in both ICDs in PD and addictive disorders. These findings point to the value of adopting a transdiagnostic approach when studying addicted populations and pave the way for demystifying this peculiar, often-devastating phenomenon in PD that has so far proven extremely difficult to treat and predict with any precision.

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The Role of PI3K/Akt and ERK in Neurodegenerative Disorders

Abstract

Disruption of Akt and Erk-mediated signal transduction significantly contributes in the pathogenesis of various neurodegenerative diseases (NDs), such as Parkinson's disease, Alzheimer's diseases, Huntington's disease, and many others. These regulatory proteins serve as the regulator of cell survival, motility, transcription, metabolism, and progression of the cell cycle. Therefore, targeting Akt and Erk pathway has been proposed as a reasonable approach to suppress ND progression. This review has emphasized on involvement of Akt/Erk cascade in the neurodegeneration. Akt has been reported to regulate neuronal toxicity through its various substrates like FOXos, GSK3β, and caspase-9 etc. Akt is also involved with PI3K in signaling pathway to mediate neuronal survival. ERK is another kinase which also regulates proliferation, differentiation, and survival of the neural cell. There has also been much progress in developing a therapeutic molecule targeting Akt and Erk signaling. Therefore, improved understanding of the molecular mechanism behind the regulatory aspect of Akt and Erk networks can make strong impact on exploration of the neurodegenerative disease pathogenesis.

http://bit.ly/2BcLvCz

The Transpetrosal Approaches System in Posterior Fossa Meningiomas Surgery: Rationale and Results

Abstract

Purpose of Review

This is a retrospective review of 90 patients with a posterior fossa meningioma (PFM) treated between 1996 and 2017 in our two tertiary skull base centers. Patients underwent surgical resection via different approaches. We aimed to show how different surgical approaches may help to reach gross total resection (GTR) and low morbidity, especially on facial nerve function.

Recent Findings

PFM is a real surgical challenge with high morbidity and mortality due to the surrounding structures, their common large size at diagnosis, and their potentially invasive behavior. Total resection is the only way to cure people affected. We successfully treated 90 cases of PFM and evaluated different surgical approaches.

Summary

GTR is the aim of the surgery as the extent of resection influences the rate of recurrence, which in turn influences the prognosis. Seventy percent (p < 0.001) of surgical patients achieved a GRT with low morbidity and no mortality.

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Reply to the Letter to the Editor of Fei Jia et al. concerning “Comparison of combined anterior–posterior approach versus posterior-only approach in neuromuscular scoliosis: a systematic review and meta-analysis” by Shao ZX, et al. [Eur Spine J; (2018) 27(9): 2213–2222]

http://bit.ly/2sYmZAj

TiO 2 nanotube arrays modified with nanoparticles of platinum group metals (Pt, Pd, Ru): enhancement on photoelectrochemical performance

Abstract

Highly ordered TiO₂ nanotube arrays (TiO₂ NTs) were synthesized by anodization method using a titanium foil and further modified with nanoparticles (Ø = 2~10 nm) of three platinum group metals (that is, platinum, palladium, and ruthenium) through potentiostatic pulsed electrodeposition method to obtain the composite material. Compared with pure TiO₂ NTs, all the three composite samples (M-TiO₂ NTs, M = Pt, Pd, Ru) showed different enhancement effects on the light responses, as well as different photoelectrochemical performances. In this study, the performance of M-TiO₂ NTs, which worked as photoanode and cathode, was investigated. Ru-TiO₂ exhibited the best degradation yield (~ 85.8%) when applied as photoanode under visible light illumination, which indicated the platinum group metal could also be induced under visible irradiation, not just served as the co-catalyst. M-TiO₂ NTs as cathode were evaluated under the hydrogen evolution reaction (HER). The three M-TiO₂ NT electrodes showed an improved efficiency over pure TiO₂ NTs, while Pt-TiO₂ NTs performed even better (without any sacrificial agent) with higher Faradic efficiency than platinum electrode in the photoelectrocatalytic hydrogen production, which could be explained by the uniform and fine metal nanoparticles on the surface of TiO₂ NTs to offer abundant active sites for the reaction.

Graphical abstract

In this paper, TiO2 nanotube arrays loaded with nanoparticles of platinum group metals have been explored on their enhancement of photoelectrocatalytic activity. Platinum group metals served as co-catalyst in the surface of TiO2 nanotubes and show great variations in different reactions.

http://bit.ly/2Gds9Ap

Verification of image quality and quantification in whole-body positron emission tomography with continuous bed motion

Abstract

Objective

Whole-body dynamic imaging using positron emission tomography (PET) facilitates the quantification of tracer kinetics. It is potentially valuable for the differential diagnosis of tumors and for the evaluation of therapeutic efficacy. In whole-body dynamic PET with continuous bed motion (CBM) (WBDCBM-PET), the pass number and bed velocity are key considerations. In the present study, we aimed to investigate the effect of a combination of pass number and bed velocity on the quantitative accuracy and quality of WBDCBM-PET images.

Methods

In this study, WBDCBM-PET imaging was performed at a body phantom using seven bed velocity settings in combination with pass numbers. The resulting image quality was evaluated. For comparing different acquisition settings, the dynamic index (DI) was obtained using the following formula: [P/S], where P represents the pass number, and S represents the bed velocity (mm/s). The following physical parameters were evaluated: noise equivalent count at phantom (NEC_phantom), percent background variability (N_10 mm), percent contrast of the 10 mm hot sphere (Q_{H, 10 mm}), the Q_{H, 10 mm}/N_10 mm ratio, and the maximum standardized uptake value (SUV_max). Furthermore, visual evaluation was performed.

Results

The NEC_phantom was equivalent for the same DI settings regardless of the bed velocity. The N_10 mm exhibited an inverse correlation (r < − 0.89) with the DI. Q_H,10 mm was not affected by DI, and a correlation between Q_H,10 mm/N_10 mm ratio and DI was found at all the velocities (r > 0.93). The SUV_max of the spheres was not influenced by the DI. The coefficient of variations caused by bed velocity decreased in larger spheres. There was no significant difference between the bed velocities on visual evaluation.

Conclusion

The quantitative accuracy and image quality achieved with WBDCBM-PET was comparable to that achieved with non-dynamic CBM, regardless of the pass number and bed velocity used during imaging for a given acquisition time.

http://bit.ly/2G2JvAQ