Oxidation of triethylene glycol and tetraethylene glycol by ditelluratocuprate(III) in alkaline medium - A kinetic and mechanistic study

The kinetics of oxidation of triethylene glycol (TEG) and tetraethylene glycol (TTEG) by ditelluratocuprate(III) (DTC) in alkaline liquids were investigated spectrophotometrically in the temperature range of 20oC to 40oC. It was found that the reaction followed pseudo-first order in DTC and less than unit order in reductants. The rate constant kobs of pseudo-first order reaction decreased with an increase of [TeO42-], whereas adding [OH-] enhanced the constant. In addition, there was a negative salt effect. A suitable assumption involving pre-equilibriums before the rate controlling step and a free radical mechanism was proposed from the kinetics study. The rate equations derived from mechanism can explain all experimental phenomena. Moreover, the activation parameters at 298.2K and rate constants of the rate-determining step were evaluated

Brain Injury Differences in Frontal Impact Crash Using Different Simulation Strategies

In the real world crashes, brain injury is one of the leading causes of deaths. Using isolated human head finite element (FE) model to study the brain injury patterns and metrics has been a simplified methodology widely adopted, since it costs significantly lower computation resources than a whole human body model does. However, the degree of precision of this simplification remains questionable. This study compared these two kinds of methods: (1) using a whole human body model carried on the sled model and (2) using an isolated head model with prescribed head motions, to study the brain injury. The distribution of the von Mises stress (VMS), maximum principal strain (MPS), and cumulative strain damage measure (CSDM) was used to compare the two methods. The results showed that the VMS of brain mainly concentrated at the lower cerebrum and occipitotemporal region close to the cerebellum. The isolated head modelling strategy predicted higher levels of MPS and CSDM 5%, while the difference is small in CSDM 10% comparison. It suggests that isolated head model may not equivalently reflect the strain levels below the 10% compared to the whole human body model

The value of property management services: an experiment

Purpose: Assessing the value of property management services is challenging because of collinearity between property quality and the quality of property management companies. In order to overcome this challenge and isolate the impact of property management services, the purpose of this paper is to use an experimental approach inspired by work in labor economics (Bertrand and Mullainathan, 2004) to measure the value of property management services for residential properties in Hong Kong. Design/methodology/approach: The authors surveyed over 150 experts in the real estate industry and asked them to estimate the value of five hypothetical properties. In each survey, the authors randomly assign different property management companies, which we have ranked by levels of quality, to the properties. In this way the authors were able to test whether property management services significantly impact property prices and whether this impact varies across types of residential buildings. Findings: Results show that property management does add value, especially to older and more dilapidated properties. Practical implications: Findings suggest that there is money to be made by high-quality companies providing services for lower quality buildings. Originality/value: The experimental survey methodology applied in this paper provides an innovative way to measure company value. © Emerald Group Publishing Limited

Multimodal magnetic resonance imaging on brain structure and function changes in subjective cognitive decline: a mini-review

Subjective cognitive decline (SCD) is the initial stage of Alzheimer’s disease (AD). Early identification of SCD and its risk factors is of great importance for targeted interventions and for delaying the onset of AD. We reviewed the relevant literature on structural magnetic resonance imaging (sMRI), diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI), and other techniques regarding SCD research in recent years. This study applied sMRI and fMRI techniques to explore abnormal brain structures and functions, which may help provide a basis for SCD diagnosis

Analysis of entropies based on empirical mode decomposition in amnesic mild cognitive impairment of diabetes mellitus

EEG characteristics that correlate with the cognitive functions are important in detecting mild cognitive impairment (MCI) in T2DM. To investigate the complexity between aMCI group and age-matched non-aMCI control group in T2DM, six entropies combining empirical mode decomposition (EMD), including Approximate entropy (ApEn), Sample entropy (SaEn), Fuzzy entropy (FEn), Permutation entropy (PEn), Power spectrum entropy (PsEn) and Wavelet entropy (WEn) were used in the study. A feature extraction technique based on maximization of the area under the curve (AUC) and a support vector machine (SVM) were subsequently used to for features selection and classification. Finally, Pearson's linear correlation was employed to study associations between these entropies and cognitive functions. Compared to other entropies, FEn had a higher classification accuracy, sensitivity and specificity of 68%, 67.1% and 71.9%, respectively. Top 43 salient features achieved classification accuracy, sensitivity and specificity of 73.8%, 72.3% and 77.9%, respectively. P4, T4 and C4 were the highest ranking salient electrodes. Correlation analysis showed that FEn based on EMD was positively correlated to memory at electrodes F7, F8 and P4, and PsEn based on EMD was positively correlated to Montreal cognitive assessment (MoCA) and memory at electrode T4. In sum, FEn based on EMD in right-temporal and occipital regions may be more suitable for early diagnosis of the MCI with T2DM

Multimodal magnetic resonance imaging on brain structure and function changes in vascular cognitive impairment without dementia

Vascular cognitive impairment not dementia (VCIND) is one of the three subtypes of vascular cognitive impairment (VCI), with cognitive dysfunction and symptoms ranging between normal cognitive function and vascular dementia. The specific mechanisms underlying VCIND are still not fully understood, and there is a lack of specific diagnostic markers in clinical practice. With the rapid development of magnetic resonance imaging (MRI) technology, structural MRI (sMRI) and functional MRI (fMRI) have become effective methods for exploring the neurobiological mechanisms of VCIND and have made continuous progress. This article provides a comprehensive overview of the research progress in VCIND using multimodal MRI, including sMRI, diffusion tensor imaging, resting-state fMRI, and magnetic resonance spectroscopy. By integrating findings from these multiple modalities, this study presents a novel perspective on the neuropathological mechanisms underlying VCIND. It not only highlights the importance of multimodal MRI in unraveling the complex nature of VCIND but also lays the foundation for future research examining the relationship between brain structure, function, and cognitive impairment in VCIND. These new perspectives and strategies ultimately hold the potential to contribute to the development of more effective diagnostic tools and therapeutic interventions for VCIND