Characterization of Carboxymethyl Cellulose (CMC) Synthesized from Microcellulose of Cassava Peel

In this study, carboxymethyl cellulose (CMC) was synthesized from the cellulose of cassava peel using alkalization and etherification reaction, and it was subsequently characterized with various techniques. Microcellulose was obtained by hydrolyzing a;-cellulose from cassava peel using H2SO4 with concentrations of 45%, 47%, and 49%. The experimental results indicate that the varying concentrations of acid affect the particle size of the cellulose, with 49% H2SO4 solution producing a cellulose with particle size of around 0.45-2.42 �m and relative percentage of 11.3% according to PSA analysis. Other analyses conducted included determination of substitution degrees, DTG/DTA/TGA, FTIR, SEM, and XRD. The value of the substitution degree was determined at 0.27. TGA decomposition thermograms at a temperature of 150oC-320oC of 19.60 % indicate CMC compounds. DTA thermograms show that these CMC compounds have endothermic properties at 140oC and exothermic properties at 260oC. FTIR spectra show the presence of absorption band at wave number 1605 cm-1, which is a characteristic absorption of carbonyl group bound to cellulose. The results of SEM analysis indicate that the CMC has a tenuous surface morphology, and the XRD diffractograms are marked by the presence of weak peak at 2e = 20o, implying the existence of CMC as mostly amorphous.

Effect of Brain Lesions on Voluntary Cough in Patients with Supratentorial Stroke: An Observational Study

Patients with stroke are known to manifest a decreased cough force, which is associated with an increased risk of aspiration. Specific brain lesions have been linked to impaired reflexive coughing. However, few studies have investigated whether specific stroke lesions are associated with impaired voluntary cough. Here, we studied the effects of stroke lesions on voluntary cough using voxel-based lesion-symptom mapping (VLSM). In this retrospective cross-sectional study, the peak cough flow was measured in patients who complained of weak cough (n = 39) after supratentorial lesions. Brain lesions were visualized via magnetic resonance imaging (MRI) at the onset of stroke. These lesions were studied using VLSM. The VLSM method with non-parametric mapping revealed that lesions in the sub-gyral frontal lobe and superior longitudinal and posterior corona radiata were associated with a weak cough flow. In addition, lesions in the inferior parietal and temporal lobes and both the superior and mid-temporal gyrus were associated with a weak peak cough flow during voluntary coughing. This study identified several brain lesions underlying impaired voluntary cough. The results might be useful in predicting those at risk of poor cough function and may improve the prognosis of patients at increased risk of respiratory complications after a stroke.

Effect of brain lesions on voluntary cough in patients with supratentorial stroke: an observational study

Background: Patients with stroke are known to manifest decreased cough force, which may increase the risk of aspiration. Specific brain lesions have been linked to impaired reflexive cough. However, only a few studies investigated whether specific stroke lesions are associated with impaired voluntary cough. The present study analyzed the effects of stroke lesion on voluntary cough using voxel-based lesion-symptom mapping (VLSM).Methods : In this retrospective cross-sectional study, the peak cough flow was measured in patients who complained of weak cough (n = 39) after supratentorial lesions. Brain lesions were analyzed via magnetic resonance imaging (MRI) at the onset of stroke. These lesions were analyzed using VLSM.Results : The VLSM method with non-parametric mapping revealed that lesions in the sub-gyral frontal lobe, superior longitudinal and posterior corona radiata were related to weak cough flow. Also, lesions in the inferior parietal and temporal lobes, and both superior and mid-temporal gyrus were also associated with weak peak cough flow during voluntary coughing.Conclusions : The present study identified several brain lesions underlying impaired voluntary cough. The results may be useful in predicting those at risk of poor coughing function and may facilitate the prognosis of patients at increased risk of respiratory complications after stroke.

SMALL-BOUND ISOMORPHISMS OF FUNCTION SPACES

Let $\mathbb{F}=\mathbb{R}$ or $\mathbb{C}$ . For $i=1,2$ , let $K_{i}$ be a locally compact (Hausdorff) topological space and let ${\mathcal{H}}_{i}$ be a closed subspace of ${\mathcal{C}}_{0}(K_{i},\mathbb{F})$ such that each point of the Choquet boundary $\operatorname{Ch}_{{\mathcal{H}}_{i}}K_{i}$ of ${\mathcal{H}}_{i}$ is a weak peak point. We show that if there exists an isomorphism $T:{\mathcal{H}}_{1}\rightarrow {\mathcal{H}}_{2}$ with $\left\Vert T\right\Vert \cdot \left\Vert T^{-1}\right\Vert <2$ , then $\operatorname{Ch}_{{\mathcal{H}}_{1}}K_{1}$ is homeomorphic to $\operatorname{Ch}_{{\mathcal{H}}_{2}}K_{2}$ . We then provide a one-sided version of this result. Finally we prove that under the assumption on weak peak points the Choquet boundaries have the same cardinality provided ${\mathcal{H}}_{1}$ is isomorphic to ${\mathcal{H}}_{2}$ .

Study on Modified Hummers Method for Partially Oxidized Graphene Oxide Synthesis

Graphene oxide (GO) is a promising material that currently a common precursor in the synthesis of graphene material. GO has emerged as a rapidly developed material due to its remarkable application in electronics, energy storage, biomedical and chemistry. However, controlling the oxygen content in the GO is one of the significant factors for tailoring GO that able to fulfil various applications. In this paper, diluted sulfuric acid was employed during the oxidation. Based on the characterization results from Fourier Transform Infrared Spectrometer (FTIR), Ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA) it found that the partially oxidized graphene oxide (PGO) was fabricated. The PGO synthesis show an insignificant absorption of C=O peak in FTIR and weak peak intensity at 300 nm for UV-Vis analysis that found in fully oxidized graphene oxide. Therefore, the PGO synthesis claimed to be partially oxidized.

Isomorphisms of spaces of affine continuous complex functions

Let $X$ and $Y$ be compact convex sets such that their each extreme point is a weak peak point. We show that $\operatorname{ext} X$ is homeomorphic to $\operatorname{ext} Y$ provided there exists a small-bound isomorphism of the space $\mathfrak{A}(X,\mathbb{C} )$ of continuous affine complex functions on $X$ onto $\mathfrak{A}(Y,\mathbb{C} )$. Further, we generalize a result of Cengiz to the context of compact convex sets.

Revealing phase boundaries by weighted parametric structural refinement

Parametric Rietveld refinement from powder diffraction data has been utilized in a variety of situations to understand structural phase transitions of materials in situ. However, when analysing data from lower-resolution two-dimensional detectors or from samples with overlapping Bragg peaks, such transitions become difficult to observe. In this study, a weighted parametric method is demonstrated whereby the scale factor is restrained via an inverse tan function, making the phase boundary composition a refinable parameter. This is demonstrated using compositionally graded samples within the lead-free piezoelectric (BiFeO3) x (Bi0.5K0.5TiO3) y (Bi0.5Na0.5TiO3)1–x–y and (Bi0.5Na0.5TiO3) x (BaTiO3)1–x systems. This has proven to be an effective method for diffraction experiments with relatively low resolution, weak peak splitting or compositionally complex multiphase samples.

Grafting of Oleic Acid On Cyclic Natural Rubber Resiprene-35 Using Dicumyl Peroxide Initiator and Divinylbenzene Compatibilizers For Paint Binder In Polyamide Thermoplastics

In this paper, we reported about modifications of Cyclic Natural Rubber (CNR) with Oleic Acid (OA) and divinylbenzene (DVB) and dicumyl peroxide (DCP). The aim of this research isto improve their compatibility as a paint binder in polyamide thermoplastic substrates. The method of this research is grafting method in order to know grafting process of CNR to generate CNR-g-OA, and its compatibility after being blended with Polyamide (PA). Analysis of CNR-g-OA was carried out by using FTIR and SEM. The results showed that the best compositions ratio of CNR-g-OA are CNR (100 phr), OA (6 phr), DCP (0.5 phr); and DVB (0.5 phr). The FTIR data of CNR-g-OA show that there is a sharp and weak peak at 1700 to 1800 cm-1, indicating that is carbonyl (C=O). It is oleic acid. The SEM data of CNR-g-OA is totally difference compare to CNR-g-OA with polyamide after the addition of DVB. It is caused the grafting was succeed to generate CNR-g-AO and compatible with PA.

Structure formation of nitrogen-containing austenitic 04Kh20N6G11M2AFB steel. Part 1: Influence of deformation temperature and strain rate on the dynamic recrystallization

The paper determines values of the deformation threshold necessary for the initiation and development of dynamic recrystallization in the investigated deformation temperature and strain rate. Analysis of diagrams shows that the deformation resistance increases with decreasing of temperature, while a weak peak is observed at temperature 1000–1200°C, when dynamic recrystallization starts. The structure of high-strength corrosion-resistant nitrogen-containing austenitic steel 04Kh20N6G11M2AFB after hot deformation with strain rate 0.1, 1.0 and 10 s-1 in the temperature range 900–1200°С has been studied by EBSD analysis and transmission electron microscopy.