Use of pullulanase as a biocatalyst for starch hydrolysis: Part 1. Study of the effect of pullulanase on maize amylopectin starch

The use of debranching enzymes in starch hydrolysis is a topical direction for obtaining new types of starch products with controlled properties and a potential for the further use. The aim of the work was to study an effect of pullulanase (EC3.2.1.41) on maize amylopectin starch in the native and gelatinized state. The objects of the research were maize amylopectin starch and enzyme preparation Promozyme D6 (Novozymes, Denmark). High-performance liquid chromatography (HPLC) was used to determine the carbohydrate composition of hydrolysates. The mass fraction of reducing substances (RS) was determined by the Lane and Eynon method. A rotational viscometer was used to measure dynamic viscosity of the starch hydrolysis products. It was found that analyzed starch in the native state showed low enzymatic sensitivity to the action of pullulanase with insignificant changes in viscosity, solubility and iodine binding capacity of the samples. Pullulanase showed the highest effect on gelatinized starch during the first eight hours of incubation. After eight hours, the maximum degree of starch hydrolysis by pullulanase at a dose of 10 units/g dry matter (DM) was 4.7% on DM basis, iodine binding capacity of the hydrolysate was D600 = 0.343 (in the control experiment D600 = 0.154), and the viscosity of the hydrolysate decreased from 7887 mPa · s to 4.3 mPa · s. Hydrolysates cooled to 8 °C and held for 20 hours along with hydrolysates that were not cooled showed high susceptibility to attack by glucoamilase (97–98%) at 60 °C and 24 hours of saccharification, which suggested the absence of their resistance to the action of glucoamilase in the conditions of the experiment. The use of pullulanase in dextrinization of the analyzed starch, which was gelatinized and partly hydrolyzed by α-amylase (RS6.1%), enabled obtaining hydrolysates with the mass fraction of reducing substances in a range of 10–24% on DM basis with the process duration of 2 to 24 hours and the enzyme dose of 2–10 units, which contained mainly maltotriose, maltohexose and maltoheptose with their total amount of 45–60% on DM basis. The results indicate a need for further research of the biocatalytic action of pullulanase to develop new methods for enzymatic modification of starch.

Optimization and Evaluation of SO2 Emissions Based on WRF-Chem and 3DVAR Data Assimilation

Emission inventories are important for modeling studies and policy-making, but the traditional “bottom-up” emission inventories are often outdated with a time lag, mainly due to the lack of accurate and timely statistics. In this study, we developed a “top-down” approach to optimize the emission inventory of sulfur dioxide (SO2) using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a three-dimensional variational (3DVAR) system. The observed hourly surface SO2 concentrations from the China National Environmental Monitoring Center were assimilated and used to estimate the gridded concentration forecast errors of WRF-Chem. The concentration forecast errors were then converted to the emission errors by assuming a linear response from SO2 emission to concentration by grids. To eliminate the effects of modelling errors from aspects other than emissions, a strict data-screening process was conducted. Using the Multi-Resolution Emission Inventory for China (MEIC) 2010 as the a priori emission, the emission inventory for October 2015 over Mainland China was optimized. Two forecast experiments were conducted to evaluate the performance of the SO2 forecast by using the a priori (control experiment) and optimized emissions (optimized emission experiment). The results showed that the forecasts with optimized emissions typically outperformed the forecasts with 2010 a priori emissions in terms of the accuracy of the spatial and temporal distributions. Compared with the control experiment, the bias and root-mean-squared error (RMSE) of the optimized emission experiment decreased by 71.2% and 25.9%, and the correlation coefficients increased by 50.0%. The improvements in Southern China were more significant than those in Northern China. For the Sichuan Basin, Yangtze River Delta, and Pearl River Delta, the bias and RMSEs decreased by 76.4–94.2% and 29.0–45.7%, respectively, and the correlation coefficients increased by 23.5–53.4%. This SO2 emission optimization methodology is computationally cost-effective.

Assimilation of Ground-Based Microwave Radiometer on Heavy Rainfall Forecast in Beijing

Ground-based microwave radiometers (MWRPS) can provide continuous atmospheric temperature and relative humidity profiles for a weather prediction model. We investigated the impact of assimilation of ground-based microwave radiometers based on the rapid-refresh multiscale analysis and prediction system-short term (RMAPS-ST). In this study, five MWRP-retrieved profiles were assimilated for the precipitation enhancement that occurred in Beijing on 21 May 2020. To evaluate the influence of their assimilation, two experiments with and without the MWRPS assimilation were set. Compared to the control experiment, which only assimilated conventional observations and radar data, the MWRPS experiment, which assimilated conventional observations, the ground-based microwave radiometer profiles and the radar data, had a positive impact on the forecasts of the RMAPS-ST. The results show that in comparison with the control test, the MWRPS experiment reproduced the heat island phenomenon in the observation better. The MWRPS assimilation reduced the bias and RMSE of two-meter temperature and two-meter specific humidity forecasting in the 0–12 h of the forecast range. Furthermore, assimilating the MWRPS improved both the distribution and the intensity of the hourly rainfall forecast, as compared with that of the control experiment, with observations that predicted the process of the precipitation enhancement in the urban area of Beijing.

An Optimal Control Experiment for an SEIRS Epidemiological Model

This work studies an optimal control model for a discrete-time Susceptible/Exposed/Infective/Removed/Susceptible (SEIRS) deterministic epidemiological model with a finite time horizon and changing population. The model presented converts a continuous SEIRS model that would typically be solved using differential equations into a discrete model that can be solved using dynamic programming. The discrete approach more closely resembles real life situations, as the number of individuals in a population, the rate of vaccination to be applied, and the time steps are all discrete values. The model utilizes a previously developed algorithm and applies it to the presented SEIRS model. To demonstrate the applicability of the algorithm, a series of numerical results are presented for various parameter values. KEYWORDS: Control; Cost; Discrete; Disease; Epidemiology; Minimization; Modeling; Optimality; SEIRS; Vaccination

TAS-102 Monotherapy and Combination Therapy with Bevacizumab for Metastatic Colorectal Cancer

Objective. To evaluate the effectiveness and safety of TAS-102 monotherapy and combination therapy with bevacizumab in the treatment of metastatic colorectal cancer. Methods. The PubMed, Web of Science, MEDLINE, and Cochrane Library databases were searched for the literature on TAS-102 treatment of metastatic colorectal cancer. Extracted data include median overall survival (mOS), median progression-free survival (mPFS), and the incidence of adverse events for meta-analysis. Results. Our study found that the mOS of patients treated with TAS-102 monotherapy was 6.95 (95% CI: 6.26-7.72) months and the mPFS was 2.53 (95% CI: 2.31-2.78) months. The mOS in patients treated by TAS-102 combined with bevacizumab was 10.41 (95% CI: 8.40-12.89) months, and the mPFS is 4.35 (95% CI: 3.05-6.20) months. In the control experiment, the patients’ mOS and mPFS were improved. TAS-102+B vs. TAS-102 ( OR = 0.41 , 95% CI: 0.18-0.93; OR = 0.72 , 95% CI: 0.63-0.83) and TAS-102 vs. placebo ( OR = 0.44 , 95% CI: 0.29-0.67; OR = 0.51 , 95% CI: 0.42-0.62) were studied to actively prevent the occurrence of neutropenia, leukopenia, febrile neutropenia, anemia, and vomiting. Conclusion. TAS-102 monotherapy and combination therapy with bevacizumab can significantly improve the survival of patients and prevent specific adverse events from happening.

The influence of toxic metals As, Cd, Ni and Pb on nutrients accumulation in Mentha piperita

Medicinal plants are, for a considerable part of the population, an important source of treatment for certain diseases. They contain essential nutrients for the human body such as magnesium, iron , and zinc. The present study shows the influence of the addition of As, Cd, Ni, Pb on mineral nutrients in different organs of Mentha piperita. The experiments were carried out in the laboratory for a period of three months (May-July). Mentha piperita plants were AsCd and AsCdNiPb exposed up to final concentrations corresponding to the soil intervention threshold according to Romanian Order no.756/1997 (25 mg/kg As, 5 mg/kg Cd, 150 mg/kg Ni and 100 mg/ kg Pb). Simultaneously with these experiments, a control experiment (M) was performed. To evaluate the effect of the addition of AsCd and AsCdNiPb on the accumulation and transfer of Ca, Cr, Cu, Mn, Mo, Fe and Zn, the transfer coefficient (TC), the translocation factor (TF), and the enrichment factor (EF) were calculated. A higher concentration of Ca, Cr, Cu, Fe, Mn, Mo, and Zn was observed especially in the mint root in the experiments in which AsCdNiPb was added compared to those in which only AsCd was added. The AsCdNiPb addition did not influence the translocation of micro and macronutrients from the root to the aerial (edible) parts of the plant. In the case of the AsCd, addition, the translocation of zinc from the root to the aerial parts (leaves and stem) of the plant was increased.

Integration of proprioceptive and visual feedback during online control of reaching

Visual and proprioceptive feedback both contribute to perceptual decisions, but it remains unknown how these feedback signals are integrated together or consider factors such as delays and variance during online control. We investigated this question by having participants reach to a target with randomly applied mechanical and/or visual disturbances. We observed that the presence of visual feedback during a mechanical disturbance did not increase the size of the muscle response significantly but did decrease variance, consistent with a dynamic Bayesian integration model. In a control experiment we verified that vision had a potent influence when mechanical and visual disturbances were both present but opposite in sign. These results highlight a complex process for multi-sensory integration, where visual feedback has a relatively modest influence when the limb is mechanically disturbed, but a substantial influence when visual feedback becomes misaligned with the limb.

Control experiment for health center users to compare the usage of hand sanitizers through nudges during the COVID-19 pandemic in Japan

To assess the effectiveness of promoting hand hygiene by nudges, the control experiment was conducted during the COVID-19 pandemic in Japan. Hand sanitizers were placed at entrances of health centers A (nudge group) and B (non-nudges/reference group). The users of each group were approximately 40 daily. In the nudge group, during week 1, the conventional notice was displayed. From weeks 2 to 4, sequential nudges based on the framework “MINDSPACE” were implemented: drawing an arrow on the floor towards a hand sanitizer, posting altruism messages, and providing trends in hand sanitizer usage. From weeks 5 to 8, no additional interventions were implemented. Until week 4, usage in the nudge group increased steeply. Although the gap narrowed after week 5, usage in the nudge group (1.7 times of week 1 usage) was higher than that in the reference group (1.4 times of week 1 usage) at week 8. The nudges cost 0.9 USD and were prepared within 3 hours. The series of nudges can be implemented with low cost and minimal efforts, and the effect may last until week 8; these nudges will meet practitioners’ needs during the COVID-19 pandemic.