Search

During yeast dough fermentation, such as the high-sucrose bread-making process, the yeast cells are subjected to considerable osmotic stress, resulting in poor outcomes. Invertase is important for catalyzing the irreversible hydrolysis of sucrose to free glucose and fructose, and decreasing the catalytic activity of the invertase may reduce the glucose osmotic stress on the yeast. In this study, we performed structural design and site-directed mutagenesis (SDM) on the Saccharomyces cerevisiae invertase (ScInV) in an Escherichia coli expression system to study the catalytic activity of ScInV mutants in vitro. In addition, we generated the same mutation sites in the yeast endogenous genome and tested their invertase activity in yeast and dough fermentation ability. Our results indicated that appropriately reduced invertase activity of yeast ScInV can enhance dough fermentation activity under high-sucrose conditions by 52%. Our systems have greatly accelerated the engineering of yeast endogenous enzymes both in vitro and in yeast, and shed light on future metabolic engineering of yeast.

The Social Responsibility (SR) commitments of Higher Education Institutions (HEIs) alongside their long-standing functions of teaching and research have been recognized in literature. However, University Social Responsibility (USR) remains a relatively unexplored topic, especially in the post-conflict societies of the Great Lakes Region of East Africa (GLREA). The main objective of this paper is to document USR best practices, challenges and opportunities in GLREA universities. To reach this objective, a search was conducted in the major academic databases, where ten studies out of 93 found from 2000 to 2020 were included for review. Additionally, universities' website materials, particularly Vision and Mission Statements (VMS) were considered to complement the review in a well established sense of USR in GLREA universities. A narrative review was conducted because quantitative data were not feasible due to a significant level of heterogeneity between the included studies. The overall findings indicated that the scholarship of engagement in the regional context is not a luxury of HEIs as it is in many western universities, but rather a necessity in countries which are still undergoing the early stages of reconstruction. Specifically, the results obtained were twofold: First, the integrated SR in GLREA universities is an emerging agenda, despite its potential for growth. Second, the development of USR in the GLREA is connected to and influenced by the history of African Higher Education, and the institutional traces of that history's influence can be found in GLREA. Finally, recommendations for USR practitioners are given, and a conclusion is drawn.

Pulmonary hypertension (PH) is a severe pulmonary vascular disease that eventually leads to right ventricular failure and death. The purpose of this study was to investigate the mechanism by which pachymic acid (PA) pretreatment affects PH and pulmonary vascular remodeling in rats.PH was induced via hypoxia exposure and administration of PA (5 mg/kg per day) in male Sprague-Dawley rats. Hemodynamic parameters were measured using a right ventricular floating catheter and pulmonary vascular morphometry was measured by hematoxylin-eosin (HE), α-SMA and Masson staining. MTT assays and EdU staining were used to detect cell proliferation, and apoptosis was analyzed by TUNEL staining. Western blotting and immunohistochemistry were used to detect the expression of proteins related to the Nrf2-Keap1-ARE pathway.PA significantly alleviated hypoxic PH and reversed right ventricular hypertrophy and pulmonary vascular remodeling. In addition, PA effectively inhibited proliferation and promoted apoptosis in hypoxia-induced pulmonary artery smooth muscle cells (PASMCs). Moreover, PA pretreatment inhibited the expression of peroxy-related factor (MDA) and promoted the expression of antioxidant-related factors (GSH-PX and SOD). Furthermore, hypoxia inhibited the Nrf2-Keap1-ARE signaling pathway, while PA effectively activated this pathway. Most importantly, addition of the Nrf2 inhibitor ML385 reversed the inhibitory effects of PA on ROS generation, proliferation, and apoptosis tolerance in hypoxia-induced PASMCs.Our study suggests that PA may reverse PH by regulating the Nrf2-Keap1-ARE signaling pathway.

Among recent measures for risk management, value at risk (VaR) has been criticized because it is not coherent and expected shortfall (ES) has been criticized because it is not robust to outliers. Recently, [Math. Oper. Res., 38, 393–417 (2013)] proposed a risk measure called median shortfall (MS) which is distributional robust and easy to implement. In this paper, we propose a more generalized risk measure called quantile shortfall (QS) which includes MS as a special case. QS measures the conditional quantile loss of the tail risk and inherits the merits of MS. We construct an estimator of the QS and establish the asymptotic normality behavior of the estimator. Our simulation shows that the newly proposed measures compare favorably in robustness with other widely used measures such as ES and VaR.

Due to the limited scenes that synthetic aperture radar (SAR) satellites can detect, the full-track utilization rate is not high. Because of the computing and storage limitation of one satellite, it is difficult to process large amounts of data of spacebome synthetic aperture radars. It is proposed to use a new method of networked satellite data processing for improving the efficiency of data processing. A multi-satellite distributed SAR real-time processing method based on Chirp Scaling (CS) imaging algorithm is studied in this paper, and a distributed data processing system is built with field programmable gate array (FPGA) chips as the kernel. Different from the traditional CS algorithm processing, the system divides data processing into three stages. The computing tasks are reasonably allocated to different data processing units (i.e., satellites) in each stage. The method effectively saves computing and storage resources of satellites, improves the utilization rate of a single satellite, and shortens the data processing time. Gaofen-3 (GF-3) satellite SAR raw data is processed by the system, with the performance of the method verified.

A series of well-defined and uniform pore-structure (WDUPS) TiO2/SiO2 supports with various percentages of rutile TiO2 was developed. Then Fe was introduced into the as-prepared WDUPS supports by incipient wetness impregnation to obtain WDUPS Fe/TiO2/SiO2 catalysts for the Fischer–Tropsch (FT) synthesis. Due to a similar surface OH density in the supports and the same pore structure and Fe loading, the catalytic performance of WDUPS catalysts dominated by percentages of rutile TiO2. Based on the catalytic performance for FT synthesis and the characterization of the H2 temperature-programmed reduction (H2-TPR) and the X-ray photoelectron spectroscopy (XPS), the results suggested that rutile TiO2 acted as a structure promoter in titania-supported iron catalysts and led to an increase in the catalytic activity during FT synthesis. The C5+ selectivity had an increase as the percentage of the rutile phase increased, which was also probably because of rutile TiO2 as a structure promoter for enhancing chain growth.

Focusing on the characteristics of public participation and large group decision making of major livelihood projects, this paper proposes a multi-agent linguistic-style large group decision-making method with the consideration of public expectations. Firstly, based on the discrimination degree of evaluating information, the comprehensive weight of each attribute is calculated with the principle of maximum entropy. Secondly, the expert preference information for different alternatives is clustered and several aggregations are formed. Thirdly, the preference conflict level of experts' group for each alternative is calculated, and a conflict-oriented experts' aggregation weight optimization model is constructed to ensure the effectiveness of conflict resolution. Fourthly, the public group's satisfaction is determined with the expectation distribution of public’s and the expert group's preference, so as to obtain the sorting result of the decision alternatives. Finally, the effectiveness and applicability of the proposed method are verified by method comparison.

This paper was to probe into whether IL-6 improved insulin resistance by AMPK and p38MAPK signal pathway. The C2C12 cell lines were purchased from ATCC. The cells of control group were cultured in high-glucose DMEM culture medium. CaCl2 with different concentrations was respectively used to culture C2C12 cells; then, glucose concentrations in the nutrient solution following 24 h were measured in the preliminary experiment. Firstly, cells of A group (control group) were normally cultured C2C12 cells, cells of B, C, and D group were respectively cultured with palmitic acid 48 h, palmitic acid 24 h, and IL-6 24 h, and IL-6-shRNA 48 h, glucose concentrations, IL-6 mRNA and GLUT4 mRNA levels, p-p38MAPK, p-AMPK, p-IRS-1, and p-PI-3K protein contents of each group in the nutrient solution following 48 h were measured. Secondly, cells of A group (control group) were palmitic acid-cultured C2C12 cells, cells of B and C group were respectively cultured with palmitic acid 24 h and CaCl2 24 h, and palmitic acid 24 h CaCl2 24 h, and IL-6-shRNA 24 h, and the same indexes were measured with the first experiment. The preliminary experimental result showed that CaCl2 feed can induce C2C12 cell contraction, and CaCl2 with different concentrations was able to decrease significantly glucose concentrations in the nutrient solution following 24 h (p

Background Malaria is still a serious public health problem on Bioko Island (Equatorial Guinea), although the number of annual cases has been greatly reduced since 2004 through the Bioko Island Malaria Control Project (BIMCP). A better understanding of malaria parasite population diversity and transmission dynamics is critical for assessing the effectiveness of malaria control measures. The objective of this study is to investigate the genetic diversity of Plasmodium falciparum populations and multiplicity of infection (MOI) on Bioko Island 7 years after BIMCP. Methods A total of 181 patients with uncomplicated P. falciparum malaria diagnosed with microscopy were collected from Bioko Island from January 2011 to December 2014. Parasite DNA was extracted using chelex-100 and species were identified using a real-time PCR followed by high-resolution melting. Plasmodium falciparum msp1 and msp2 allelic families were determined using nested PCR. Results Three msp1 alleles (K1, MAD20, and RO33) and two msp2 alleles (FC27 and 3D7) were analysed in all samples. In msp1, the MAD20 allelic family was predominant with 96.69% (175/178) followed respectively by the K1 allelic family with 96.07% (171/178) and R033 allelic family with 70.78% (126/178). In msp2, the FC27 allelic family was the most frequently detected with 97.69% (169/173) compared to 3D7 with 72.25% (125/173). Twenty-six different alleles were observed in msp1 with 9 alleles for K1, 9 alleles for MAD20 and 8 alleles for R033. In msp2, 25 individual alleles were detected with 5 alleles for FC27 and 20 alleles for 3D7. The overall MOI was 5.51 with respectively 3.5 and 2.01 for msp1 and msp2. A significant increase in overall MOI was correlated with the age group of the patients (P = 0.026) or parasite densities (P = 0.04). Conclusions The present data showed high genetic diversity and MOI values among the P. falciparum population in the study, reflecting both the high endemic level and malaria transmission on Bioko Island. These data provide valuable information for surveillance of P. falciparum infection and for assessing the appropriateness of the current malarial control strategies in the endemic area.

Background and Aims Competition between intercropped species is important for yield advantage, but little attention has been given to interspecific competitive dynamics in intercropping.

The crystal structures of complexes [Tb(3-Br-4-MBA)3phen]2(1), [Ho(3-Br-4-MBA)3(phen)H2O]2(2) and [Er(3-Br-4-MBA)3(phen)H2O]2(3) (3-Br-4-MBA=3-bromine-4-methylbenzoate, phen=1,10-phenanthroline) have been solved by single-crystal X-ray diffraction methods. All obtained products were examined and characterized by elemental analysis, molar conductivity, IR, UV and XRD techniques. The thermogravimetric analysis of 1 to 3 was studied, indicating that the decomposition processes of 2 and 3 are different from 1. The mass loss of the first step for 2 and 3 is attributed to the H2O molecules. The three-dimensional IR accumulation spectra of gaseous of 1 to 3 were also recorded. Complex 1 emits strong and bright green fluorescence under UV light at the room temperature. The bacteriostatic activities of the three complexes against bacteria, such as Escherichia coli and Staphylococcus aureus, and fungus (Candida albicans) were tested.

In this paper, a new decision making approach is proposed for the multi-attribute large group emergency decision-making problem that attribute weights are unknown and expert preference information is expressed by generalized interval-valued trapezoidal fuzzy numbers (GITFNs). Firstly, a degree of similarity formula between GITFNs is presented. Secondly, expert preference information on different alternatives is clustered into several aggregations via the fuzzy clustering method. As the clustering proceeds, an index of group preference consistency is introduced to ensure the clustering effect, and then the group preference information on different alternatives is obtained. Thirdly, the TOPSIS method is used to rank the alternatives. Finally, an example is taken to show the feasibility and effectiveness of this approach. These method can ensure the consistency degree of group preference, thus decision efficiency of emergency response activities can be improved.

In this paper, according to the characteristics of floods, the closeness centrality of complex network is improved to analyze the evolution of flood disaster social stability risks. Based on the investigation conducted on the flood occurred in Hunan Province in August 2013, and related papers, the topology map for the evolution of flood social stability risk is analyzed and constructed by means of the improved closeness centrality. On this basis, the evolution of social stability risks incurred in floods is divided into three grades, in which such risks as house collapse, crops ruining, looting shopping, social panic etc. produce the maximum impacts on the entire evolution system. So, during the disaster relief, priority should be given to resolve the difficulties in meeting the basic necessities that are closely associated with people’s life.

A carbon ceramic electrode was modified with a thin film composed of overoxidized polypyrrole, CuO and multi-walled carbon nanotubes. The surface morphology, electrochemical properties and electrocatalytic activity towards the oxidation of glucose of the modified electrode were studied in detail. Benefiting from the high electrocatalytic activity of CuO, the selectivity of OPpy film, and the fast electron transfer rate promoted by MWCNTs, this modified electrode displays good stability, selectivity, high electrocatalytic activity and a low detection limit for the determination of glucose in pH 13 solution. Under the optimum conditions, the linear range for the determination of glucose by cyclic voltammetry is from 20 μM to 10 mM, and the detection limit is 4.0 μM (at an SNR of 3). The amperometric calibration plot covers the 0.20 μM to 2.0 mM concentration range, and the detection limit is 50 nM. The highest sensitivity for the determination of glucose is 3922.6 μA mM−1 cm2.

Our study indicates suspended water films, driven by crossed square-wave electric fields, may act as “washers”, “centrifuges” and “mixers”. Based on our recent model successfully describing experimentally observed electro-hydrodynamical flows in water films, we derive conditions for generating specific rotational flows. Our main findings, which are advantageous for microfluidic devices and basic research, are as follows: (1) the film’s rotational patterns depend on the phase difference $$\Updelta\varphi$$ and frequencies f of the applied fields. (2) For $$\Updelta\varphi=\pi/2$$ and $$f\sim10^{-1}-10^{0}$$ Hz, the film exhibits symmetrical reciprocating rotations, i.e. it constitutes a washer. (3) For $$\Updelta\varphi=0$$ and any f, it exhibits an ordinary anticlockwise (or clockwise) rotation, i.e. it constitutes a centrifuge or motor. (4) For $$\Updelta\varphi$$ with other values and f below 1 Hz, it exhibits asymmetrical reciprocating rotations, it constitutes an asymmetrical mixer.

The aim of this study was to determine if there has been improvement in survival for patients with gallbladder cancer treated with surgical procedures. A retrospective review of all patients with gallbladder cancer admitted during the past 11 years was conducted. The patients were categorized into two periods: period 1, from 1 January 2000 to 31 December 2005 (group 1, n = 77); and period 2, from 1 January 2006 to 31 December 2010 (group 2, n = 131). The two groups have similar age, sex distribution, and symptoms. There were more patients with advanced stage in group 2 (P = 0.001). And patients in group 2 were treated with more aggressive surgical procedures compared with group 1. Patients of group 2 had a better surgical outcomes and longer 5-year overall survival (9 % vs. 19 %, P = 0.040) and disease-free survival (P = 0.017). Median survival in group 1 was 14.7 months, while in group 2 it was 22.3 months. Patients underwent R0 resection in group 2 had better survival than that in group 1 (P = 0.009), while they had similar survival for those who underwent non-R0 resection in both periods (P = 0.108). A significant improvement of disease-free survival and long-term survival results was observed in the past decade.

In the synthetic aperture radar (SAR) system with low pulse repetition frequency (PRF) sampling, it is difficult for the motion parameters estimation of the moving targets, because of the Doppler spectrum ambiguity and Doppler centroid frequency ambiguity of the echo signals. Considering that moving targets are sparsely distributed in the observed scene, their positions and velocities can be reconstructed by using the compressed sensing (CS) technique. In this paper, the range-walk correction are implemented by the Keystone transform and the sparse range-walk correction (SRWC), then the CS technique is proposed to reconstruct motion parameters by processing the azimuth signals of the moving targets. Experiments using the simulated and real data are performed, and the results confirm the validity of the proposed method.

According to the characteristics of narrow-band radar echoes from spinning targets, this paper applies the complex-valued back-projection method to image formation. Since it accumulates the sinusoidal phase of spinning scatterers effectively, this method can obtain high resolution imaging. The resolution and required radar pulse repetition frequency (PRF) of this method are deduced. For imaging of fast spinning targets, however, spurious peaks appear due to azimuth down sampling with a low PRF. Therefore, a signal model of azimuth down-sampled echoes is created according to the compressed sensing (CS) theory. Then an imaging method based on orthogonal matching pursuit (OMP) is proposed according to the sparsity nature of ISAR echoes. Finally, the effectiveness of the proposed methods is demonstrated using simulated data.

A model, influence of water and salt on vegetation (IWSV), was developed to evaluate their influence on plant species. The main function of this model was to calculate a comprehensive index value for evaluating the suitability of plant growth. This model consists of five explanatory variables (vadose zone moisture content, vadose zone salinity, vadose zone lithology, depth to the water table, and groundwater mineralization) and two response variables (plant species and their cover). A set of independent data on three plant species, Artemisia ordosica, Salix psammophila, and Carex enervis, which are dominant species in the Mu Us Desert of northern China, were used to validate the model. Validation results show an overall correct prediction for the distribution of these three species. The results demonstrated that the IWSV model can be a useful tool for groundwater management and nature conservation in a semi-arid desert region, especially for predicting the vegetation distribution in areas with groundwater extraction.

The antimicrobial resistance and the character of integrons were determined in 58 Shigella flexneri strains isolated from China. All isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). No intI3 was detected. The typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient E. coli DH5α. The gene cassettes of typical class 1 integrons dfrA17-aadA5 and dfrA12-orfF-aadA2 were detected in 54 strains (93.1%) and 1 strain, respectively. Atypical class 1 integrons located on the chromosome with gene cassettes bla (oxa-30)-aadA1 were detected in 55 isolates (94.8%). All the intI2 positive isolates carried gene cassettes dfrA1-sat1-aadA1. To our knowledge, this is the first report that atypical and typical class 1 integrons coexisted with class 2 integron in multi-drug resistant S. flexneri strains.

Based on statistical damage mechanics, the constitutive model of a rock under three-dimensional stress was established by the law that the statistical strength of rock micro-element obeys Weibull distribution. The acoustic emission (AE) evolution model of rock failure was put forward according to the view that rock damage and AE were consistent. Moreover, in the failure process of rock under three-dimensional stress, the change in relationship between stress condition parameter and the characteristic parameters of AE, such as the event number and its change rate, were studied. Also, the rock AE characteristic under uniaxial compression was analyzed in theory and verified with examples. The results indicate that the cumulative event number and change rate of AE in rock failure are determined by stress state parameter F. Along with the gradual increase of F, first the cumulative event number increases gradually, then rapidly, and then slowly after the stress peak. The form of change rate of an event by increasing F is consistent with the distribution form of rock micro-element strength. The model explained the phenomenon that a relatively quiet period of AE appears before rock rupture that is observed by many researchers in experiments. Verification examples indicate that the AE evolution model is consistent with the test results, so the model is reasonable and correct.

The effects of various toxic carbonyls such as malondialdehyde (MDA), a secondary product of lipid peroxidation, and other aldehydes on rheological parameters and their relationship with aging-associated alterations were studied. Both MDA and glutaraldehyde (Glu) in different concentrations significantly increase viscosity, plastic viscosity and yield stress of human plasma and erythrocyte suspensions. MDA (20 mmol/L) reduces sharply the typical fluorescence of proteins (excitation 280 nm/emission 350 nm), and produces age pigment-like fluorescence with a strong emission peak at 460 nm when excites at 395 nm by only being incubated for some hours. In contrast, Glu decreases merely the fluorescence of proteins without producing age pigment-like fluorescence. These data suggest interestingly that the MDA-induced gradual protein cross linking seems to form from different mechanisms compared to the fast rheological changes of blood materials which may take place either in acute and chronic diseases or during aging. On the other hand, MDA induces various deleterious alterations of erythrocytes whereas glutathione (GSH) inhibits the MDA-related carbonyl stress in a concentration-dependent manner. The results indicate that carbonyl-amino reaction exists in the blood widely and GSH has the ability to interrupt or reverse this reaction in a certain way. It implies that carbonyl stress may be one of the important factors in blood stasis and suggests a theoretical and practical approach in anti-stresses and anti-aging.

Water-wings, induced by the middle-pier placed in the inlet of a discharge tunnel, have harmful effects on the operation of the discharge tunnel. Based on dimensional analysis and physical model tests, the hydraulic characteristics of water-wings were investigated and their causes were analyzed in this study. The results show that the height and length of the water-wings increased with the increase of three factors, i.e., the Froude number Frd of the outlet of the pressure section, the depth Hc of the water surface concave at the end of the middle-pier, and the impact length Li of the two flows after this end.

The sap flux density (SFD) was used as a measure of water capacity through stems of eucalyptus in this paper. It was found that daily SFD increased with daily vapor pressure deficit (VPD) in nonlinear regression Y=AX 3+BX 2+CX+D (R 2=0.702 1, n=135, p=0.01) at both sites (Hetou and Jijia) in the Leizhou Peninsula, Guangdong Province, China, where Y was daily SFD, X was mean daily VPD, A, B, C, D were constants. But extremely high VPD might limit stem water conductivity. The environmental factors, such as air vapor pressure deficit (VPD), solar radiation (RAD), etc., were the main determinants of SFD for E. urophylla plantations. The upper threshold of diurnal SFD was 51.55–55.65 mL·cm−2·h−1 under the selected extremely high environmental conditions.