Preparation and characterization of starch /cellulose composite

Novel preparative method for starch/cellulose composite in different ratios has been reported. The composite is obtained by mixing cellulose extracted from paper garbage and corn starch in PEG/NaOH solution. Starch/cellulose composite is characterized by different techniques, namely XRD, TGA and optical absorption measurements. From XRD data, it is observed that cellulose would lead to expand the d-spacing of (1ī0 plane and decrease the d-spacing of (110) plane of starch. The UV absorption peaks are shifted towards the longest wavelengths in the visible region for starch/cellulose composite. However, the refractive index value decreases from 1.44 to 1.08 and consequently the dielectric constant value decreases from 2.07 to 1.16 with increasing the starch ratio. Furthermore, the glass transition temperature increases from 107 °C for starch to 115 °C for starch/cellulose composite. However, the excess in starch ratio leads to increase in local crosslink density in the composite network

Recent developments in chemical reactivity of N,N-dimethylenamino ketones as synthons for various heterocycles

The current review presents recent progress in the utility of N,N-dimethyl enaminones as building blocks for a diverse range of acyclic, carbocyclic, five- and six-membered heterocyclic a broad range of heterocyclic and fused heterocyclic derivatives. Most importantly, these N,N-dimethyl analogues have proven to be of biological interest and provide an access to new class of biologically active heterocyclic compounds for biomedical applications. All of these topics are drawn from the recent literature till 2016

Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic

Introduction Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality. Methods Prospective cohort study in 109 institutions in 41 countries. Inclusion criteria: children <18 years who were newly diagnosed with or undergoing active treatment for acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, retinoblastoma, Wilms tumour, glioma, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, medulloblastoma and neuroblastoma. Of 2327 cases, 2118 patients were included in the study. The primary outcome measure was all-cause mortality at 30 days, 90 days and 12 months. Results All-cause mortality was 3.4% (n=71/2084) at 30-day follow-up, 5.7% (n=113/1969) at 90-day follow-up and 13.0% (n=206/1581) at 12-month follow-up. The median time from diagnosis to multidisciplinary team (MDT) plan was longest in low-income countries (7 days, IQR 3-11). Multivariable analysis revealed several factors associated with 12-month mortality, including low-income (OR 6.99 (95% CI 2.49 to 19.68); p<0.001), lower middle income (OR 3.32 (95% CI 1.96 to 5.61); p<0.001) and upper middle income (OR 3.49 (95% CI 2.02 to 6.03); p<0.001) country status and chemotherapy (OR 0.55 (95% CI 0.36 to 0.86); p=0.008) and immunotherapy (OR 0.27 (95% CI 0.08 to 0.91); p=0.035) within 30 days from MDT plan. Multivariable analysis revealed laboratory-confirmed SARS-CoV-2 infection (OR 5.33 (95% CI 1.19 to 23.84); p=0.029) was associated with 30-day mortality. Conclusions Children with cancer are more likely to die within 30 days if infected with SARS-CoV-2. However, timely treatment reduced odds of death. This report provides crucial information to balance the benefits of providing anticancer therapy against the risks of SARS-CoV-2 infection in children with cancer

DFT Study of Copper-Nickel (111) Catalyst for Methane Dry Reforming

No one can deny that the increasing energy demand -due to world population booming- and climate change are two major challenges facing humanity in the current century. Climate change phenomenon is basically related to green house gases (GHGs) emissions which result in increasing temperature of earth. Among GHGs, COV2 is the major contributor in global warming while CHV4 is considered a major energy source as the main component of natural gas. Dry reforming of methane (DRM) achieves utilization of both COV2 with CHV4 by producing syngas which can be converted into valuable compounds. Thus, DRM is a currently a hot subject in both industrial catalysis and environmental research. The applicability of DRM in industry is hindered by its high energy demand and coke formation on catalyst surface which leads to rapid catalyst deactivation. Nickel catalyst is well-known for an activity comparable to those of the expensive and abundant noble metals. However, pure Ni catalyst can suffer from severe coke formation at the elevated temperatures required for DRM reaction. To reduce coke formation, Nibimetallic catalysts are examined as they have shown reasonable activity and reduced carbon deposition. Several nickel-transition metals bimetallic catalysts showed their potential for coke resistance and improved activity. While the synergetic effects of CoNi-bimetallic catalyst is found to be due to its oxophilicty, Ni-Fe catalyst activity is attributed to redox system formation. However, Cu behavior of coke resistance and activity enhancement is still not well-defined at molecular level at the time of this study. This study uses DFT (Density Functional Theory) computational methods to evaluate DRM reaction on Ni2Cu (111) bimetallic catalyst. The study will reveal how different species of elementary reactions are adsorbed on catalyst surface, explore the reaction mechanism and investigate the role of atomic oxygen as well as hydroxide species in carbon removal and catalyst stability in presence of Cu in the Ni-Ni network. The results will also explain the dominant reaction pathway by calculating the activation energy barriers of different elementary reactions and contribute to design of new stable and coke-resistant catalyst that can be used for DRM on the industrial scale

DFT Study of Copper-Nickel (111) Catalyst for Methane Dry Reforming

No one can deny that the increasing energy demand -due to world population booming- and climate change are two major challenges facing humanity in the current century. Climate change phenomenon is basically related to green house gases (GHGs) emissions which result in increasing temperature of earth. Among GHGs, COV2 is the major contributor in global warming while CHV4 is considered a major energy source as the main component of natural gas. Dry reforming of methane (DRM) achieves utilization of both COV2 with CHV4 by producing syngas which can be converted into valuable compounds. Thus, DRM is a currently a hot subject in both industrial catalysis and environmental research. The applicability of DRM in industry is hindered by its high energy demand and coke formation on catalyst surface which leads to rapid catalyst deactivation. Nickel catalyst is well-known for an activity comparable to those of the expensive and abundant noble metals. However, pure Ni catalyst can suffer from severe coke formation at the elevated temperatures required for DRM reaction. To reduce coke formation, Nibimetallic catalysts are examined as they have shown reasonable activity and reduced carbon deposition. Several nickel-transition metals bimetallic catalysts showed their potential for coke resistance and improved activity. While the synergetic effects of CoNi-bimetallic catalyst is found to be due to its oxophilicty, Ni-Fe catalyst activity is attributed to redox system formation. However, Cu behavior of coke resistance and activity enhancement is still not well-defined at molecular level at the time of this study. This study uses DFT (Density Functional Theory) computational methods to evaluate DRM reaction on Ni2Cu (111) bimetallic catalyst. The study will reveal how different species of elementary reactions are adsorbed on catalyst surface, explore the reaction mechanism and investigate the role of atomic oxygen as well as hydroxide species in carbon removal and catalyst stability in presence of Cu in the Ni-Ni network. The results will also explain the dominant reaction pathway by calculating the activation energy barriers of different elementary reactions and contribute to design of new stable and coke-resistant catalyst that can be used for DRM on the industrial scale

Semitone frequency mapping to improve music representation for nucleus cochlear implants

The frequency-to-channel mapping for Cochlear implant (CI) signal processors was originally designed to optimize speech perception and generally does not preserve the harmonic structure of music sounds. An algorithm aimed at restoring the harmonic relationship of frequency components based on semitone mapping is presented in this article. Two semitone (Smt) based mappings in different frequency ranges were investigated. The first, Smt-LF, covers a range from 130 to 1502 Hz which encompasses the fundamental frequency of most musical instruments. The second, Smt-MF, covers a range from 440 to 5040 Hz, allocating frequency bands of sounds close to their characteristic tonotopical sites according to Greenwood's function. Smt-LF, in contrast, transposes the input frequencies onto locations with higher characteristic frequencies. A sequence of 36 synthetic complex tones (C3 to B5), each consisting of a fundamental and 4 harmonic overtones, was processed using the standard (Std), Smt-LF and Smt-MF mappings. The analysis of output signals showed that the harmonic structure between overtones of all complex tones was preserved using Smt mapping. Semitone mapping preserves the harmonic structure and may in turn improve music representation for Nucleus cochlear implants. The proposed semitone mappings incorporate the use of virtual channels to allow frequencies spanning three and a half octaves to be mapped to 43 stimulation channels. A pitch difference limen test was done with normal hearing subjects discriminating pairs of pure tones with different semitone intervals which were processed by a vocoder type simulator of CI sound processing. The results showed better performance with wider semitone intervals. However, no significant difference was found between 22 and 43 channels maps

Design Automation of Low Dropout Voltage Regulators: A General Approach

Analog design is an inherently intricate process comprising many trade-offs; as a result, it is an iterative time-consuming operation. A low dropout voltage regulator (LDO) is an example of such analog blocks that involve a myriad of trade-offs. In this paper, we present an automated design procedure for LDOs using precomputed look-up tables (LUTs) and the gm/ID methodology. Using a symbolic solver and the precomputed LUTs, a design database for an LDO that contains one million design points is generated in a few seconds. The database provides visualization of the design space and exploration of the trade-offs across different corners and load currents. A design example is provided to demonstrate the procedure using 40 nm technology and the results are verified using Cadence Spectre simulator. The approach is holistic in the sense that it uses an accurate symbolic solver to capture the small signal model complexities, incorporates LUTs for accurate calculation of the large signal solution and the small signal parameters, is fast because the simulator in the loop scenario is omitted, and almost all the specifications of LDOs are incorporated

Semitone frequency mapping to improve music representation for nucleus cochlear implants

Abstract The frequency-to-channel mapping for Cochlear implant (CI) signal processors was originally designed to optimize speech perception and generally does not preserve the harmonic structure of music sounds. An algorithm aimed at restoring the harmonic relationship of frequency components based on semitone mapping is presented in this article. Two semitone (Smt) based mappings in different frequency ranges were investigated. The first, Smt-LF, covers a range from 130 to 1502 Hz which encompasses the fundamental frequency of most musical instruments. The second, Smt-MF, covers a range from 440 to 5040 Hz, allocating frequency bands of sounds close to their characteristic tonotopical sites according to Greenwood's function. Smt-LF, in contrast, transposes the input frequencies onto locations with higher characteristic frequencies. A sequence of 36 synthetic complex tones (C3 to B5), each consisting of a fundamental and 4 harmonic overtones, was processed using the standard (Std), Smt-LF and Smt-MF mappings. The analysis of output signals showed that the harmonic structure between overtones of all complex tones was preserved using Smt mapping. Semitone mapping preserves the harmonic structure and may in turn improve music representation for Nucleus cochlear implants. The proposed semitone mappings incorporate the use of virtual channels to allow frequencies spanning three and a half octaves to be mapped to 43 stimulation channels. A pitch difference limen test was done with normal hearing subjects discriminating pairs of pure tones with different semitone intervals which were processed by a vocoder type simulator of CI sound processing. The results showed better performance with wider semitone intervals. However, no significant difference was found between 22 and 43 channels maps.</p

Preparation and characterization of starch /cellulose composite

190-194<span style="font-size:9.0pt;mso-bidi-font-size: 12.0pt;mso-bidi-font-family:" times="" new="" roman""="" lang="EN-GB">Novel preparative method for starch/cellulose composite in different ratios has been reported. The composite is obtained by mixing cellulose extracted from paper garbage and corn starch in PEG/NaOH solution. Starch/cellulose composite is characterized by different techniques, namely XRD, TGA and optical absorption measurements. From XRD data, it is observed that cellulose would lead to expand the d-spacing of (10 plane and decrease the d-spacing of (110) plane of starch. The UV absorption peaks are shifted towards the longest wavelengths in the visible region for starch/cellulose composite. However, the refractive index value decreases from 1.44 to 1.08 and consequently the dielectric constant value decreases from 2.07 to 1.16 with increasing the starch ratio. Furthermore, the glass transition temperature increases from 107 °C for starch to 115 °C for starch/cellulose composite. However, the excess in starch ratio leads to increase in local crosslink density in the composite network. </span