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Periplaneta americana, one of the most widely distributed insects all over the world, can survive and reproduce in harsh environment which may be closely related to the critical roles of intestinal microorganisms in its multiple physiological functions. However, the composition and structure of gut microbiota throughout different life stages and its effects on the strong resilient and environmental adaptability of P. americana remain unclear. In this study, the gut microbiota across life stages including ootheca (embryos), nymph and adult of P. americana were investigated by 16S rRNA high-throughput sequencing. Multivariate statistical analysis showed the richness and diversity of bacterial communities were significantly different among ootheca, nymph and adult stage of P. americana. Taxonomic analysis showed Blattabacterium was the dominant genus in bacterial community of ootheca while the nutrient absorption-related genera including Christensenellaceae and Ruminococcaceae showed high relative abundance in nymph samples. Moreover, functional prediction analysis showed the metabolic categories in ootheca might have more influence on the basic life activities of the host than improved production and viability, while it was more associated to the society activities, reproduction and development of host in nymph and adult. It was suggested that the gut microbiota in each life stage might meet the requirements for environmental adaptability and survival of P. americana via transforming the composition and structure with specific metabolic capabilities. Overall, these results provided a novel sight to better understand the strong vitality and adaptability throughout life stages of P. americana.
The global transition towards diets high in calories has contributed to 2.1 billion people becoming overweight, or obese, which damages male reproduction and harms offspring. Recently, more and more studies have shown that paternal exposure to stress closely affects the health of offspring in an intergenerational and transgenerational way. SET Domain Containing 2 (SETD2), a key epigenetic gene, is highly conserved among species, is a crucial methyltransferase for converting histone 3 lysine 36 dimethylation (H3K36me2) into histone 3 lysine 36 trimethylation (H3K36me3), and plays an important regulator in the response to stress. In this study, we compared patterns of SETD2 expression and the H3K36me3 pattern in pre-implantation embryos derived from normal or obese mice induced by high diet. The results showed that SETD2 mRNA was significantly higher in the high-fat diet (HFD) group than the control diet (CD) group at the 2-cell, 4-cell, 8-cell, and 16-cell stages, and at the morula and blastocyst stages. The relative levels of H3K36me3 in the HFD group at the 2-cell, 4-cell, 8-cell, 16-cell, morula stage, and blastocyst stage were significantly higher than in the CD group. These results indicated that dietary changes in parental generation (F0) male mice fed a HFD were traceable in SETD2/H3K36me3 in embryos, and that a paternal high-fat diet brings about adverse effects for offspring that might be related to SETD2/H3K36me3, which throws new light on the effect of paternal obesity on offspring from an epigenetic perspective.
In this paper, we study existence of rotating periodic solutions for p-Laplacian differential systems. We first build a new continuation theorem by topological degree, and then obtain the existence of rotating periodic solutions for two kinds of p-Laplacian differential systems via this continuation theorem, extend some existing relevant results.
This paper aims to investigate the existence of periodic solutions for $p$-Laplacian differential equations with jumping nonlinearity under the frame of half-eigenvalue. Based on the continuity theorem, some new results are obtained, which enrich and generalize the previous results.
Many studies have focused on the optimization of the composition of embryo culture medium; however, there are few studies involving the effect of a culture medium changing procedure on the preimplantation development of embryos. In this study, three groups were designed: a non-renewal group, a renewal group and a half-renewal group. The levels of reactive oxygen species (ROS), apoptotic index, blastocyst ratio and blastocyst total cell number were analyzed in each group. The results showed that the ROS level and the apoptotic index of blastocyst in the non-renewal group were significantly higher than in the renewal group and the half-renewal group (P < 0.05). The blastocyst ratio and blastocyst total cell number were significantly higher in the half-renewal group than that in non-renewal group and the renewal group (P < 0.05). These results demonstrated that the procedure of changing the culture medium influenced ROS level, apoptotic index, blastocyst ratio and total cell number of blastocysts. In addition, the result suggested that changing the culture medium may lead to a loss of important regulatory factors for embryos, while not changing the culture medium may lead to the accumulation of toxic substances. Half-renewal can alleviate the defects of both no renewal and renewal, and benefit embryo development. This study will be of high value as a reference for the optimization of embryo culture in vitro, and is very significant for assisted reproduction.
The low efficiency of somatic cell nuclear transfer (SCNT) greatly limits its application. Compared with the fertilized embryo, cloned embryos display abnormal epigenetic modification and other inferior developmental properties. In this study, small RNAs were isolated, and miR-34c and miR-125b were quantified by real-time PCR; results showed that these micro-RNAs were highly expressed in sperm. The test sample was divided into three groups: one was the fertilized group, one was the SCNT control group (NT-C group), and the third group consisted of SCNT embryos injected with sperm-borne small RNA (NT-T group). The level of tri-methylation of lysine 9 on histone H3 (H3K9me3) at the 8-cell stage was determined by immunofluorescence staining, and the cleavage ratio, blastocyst ratio, apoptotic cell index of the blastocyst and total cell number of blastocysts in each group were analyzed. Results showed that the H3K9me3 level was significantly higher in the NT-C group than in the fertilized group and the NT-T group. The apoptosis index of blastocysts in the NT-C group was significantly higher than that in the fertilized group and the NT-T group. The total cell number of SCNT embryos was significantly lower than that of fertilized embryos, and injecting sperm-borne small RNAs could significantly increase the total cell number of SCNT blastocysts. Our study not only demonstrates that sperm-borne small RNAs have an important role in embryo development, but also provides a new strategy for improving the efficiency of SCNT in rabbit.
'Missing wedge' problem exists in some kind of CT imaging situations, such as electron microscopy, x-ray nano-CT image, etc. Method such as iterative reconstruction algorithms, total variation based method were applied to improve the reconstruction quality, but the 'missing wedge' artifacts are still inevitable. In this paper, a method based on image processing technique was proposed to locate the 'missing wedge' artifacts in CT reconstruction. The result showed good performance on locating the artifacts, which also showed the potential in CT reconstruction and image analysis in nano-CT.
The effect of current direction (CD) on the microstructural evolution and mechanical properties of a Cu–Zn binary phase (α + β) alloy during the primary process of phase transformation induced by electric current pulses (ECP) treatment was investigated. To clarify the effect of CD, the samples were prepared with different angles between the CD and rolling direction (RD) from 0° to 90°. Results showed that not only the microstructural evolution but also the corresponding mechanical properties all had a saddle point in the sample with the angle 45°. Analyzed from the mechanical properties, it could be found that the anisotropic of the materials becomes stronger due to the application of ECP. An important finding is that by changing the angles between the CD and the RD, a novel and effective approach to control the phase transformation process could be provided.
Objectives: The aim of this study was to examine the gaps between researchers and policy makers in perceptions and influencing factors of knowledge translation (KT) of health technology assessment (HTA) in China.
Methods: A sample of 382 HTA researchers and 112 policy makers in China were surveyed using structured questionnaires. The questionnaires contained two sections: perceptions of HTA research and assessments of six-stage KT activities. Wilcoxon rank sum test was applied to compare the differences in these two sections between HTA researchers and policy makers. Multivariate linear regression was performed to explore KT determinants of HTA for researchers and policy makers separately.
Results: Policy makers and researchers differed in their perceptions of HTA research in all items except collaboration in research development and presentation of evidence in easy-to-understand language. Significant differences in KT activities existed in all the six stages except academic translation. Regarding KT determinants, close contact between research unit and policy-making department, relevance of HTA to policy making, and importance of HTA on policy making were considered facilitators by both groups. For researchers, practicality of HTA report and presentation of evidence in easy-to-understand language can facilitate KT. Policy makers, on the other hand, considered an overly pedantic nature of HTA research as an obstacle to effective KT.
Conclusions: Substantial gaps existed between HTA researchers and policy makers regarding the perceptions of HTA research and KT activities. There are also some differences in KT determinants by these two groups. Enhancing collaboration, promoting practicality and policy relevance of HTA research, and making HTA findings easily understood are likely to further the KT of HTA evidence.
In this paper, we study the mathematical formulation for an optimal control problem governed by a linear parabolic integro-differential equation and present the optimality conditions. We then set up its weak formulation and the finite element approximation scheme. Based on these we derive the a priori error estimates for its finite element approximation both in H1 and L2 norms. Furthermore some numerical tests are presented to verify the theoretical results.
In the preparation process for scanning electron microscopy (SEM), flexed silkworm embryos typically assume several curled shapes with irregular postures that obscure morphological details during SEM observation. We describe a preparation technique based on glycerol substitution for better SEM visualization of straight and flat silkworm embryos. Glycerol has high viscosity, low vapor pressure, and sufficient electrical conductivity. Silkworm embryos were infiltrated with glycerol and arranged in a straight posture or flattened using a cover slip. Samples were directly observed by SEM without additional dehydration, drying, or coating procedures. The complete ventral side could be easily viewed in one image. Recoating alleviated the charging phenomenon. This represents a simple method for preparation of straight and flat samples from curled biological specimens for SEM observation.
Intra-uterine growth retardation (IUGR) impairs postnatal growth and development of the small intestine (SI) in neonatal pigs and infants. l-Arginine (Arg), a critical amino acid involved in promoting growth and metabolism in young mammals, is more deficient in IUGR fetuses. However, little is known whether dietary Arg supplementation would accelerate the impaired development of the SI induced by IUGR in piglets. In the present study, a total of six litters of newborn piglets were used. In each litter, one normal and two IUGR littermates were obtained. Piglets were fed milk-based diets supplemented with 0 (Normal), 0 (IUGR) and 0·60% Arg (IUGR+Arg) from 7 to 14 d of age, respectively. Compared with Normal piglets at 14 d of age, IUGR decreased (P < 0·05) the growth performance, entire SI weight, and villus height in the jejunum and ileum. IUGR piglets had lower (P < 0·05) mucosal concentrations of Arg, insulin, insulin growth factor 1, as well as phosphorylated Akt, mammalian target of rapamycin (mTOR) and p70 S6 kinase but higher (P < 0·05) enterocyte apoptosis index (AI). After Arg treatment in IUGR piglets, the growth performance, weight of entire SI and mucosa, and villus height in the jejunum and ileum were increased (P < 0·05). Diet supplemented with Arg also increased (P < 0·05) the levels of Arg, insulin, phosphorylated Akt and mTOR in SI mucosa of IUGR piglets, and decreased (P < 0·05) the AI and caspase-3 activity. In conclusion, Arg has a beneficiary effect in improving the impaired SI development in IUGR piglets via regulating cell apoptosis and activating Akt and mTOR signals in SI mucosa.
We study the effects of emergent coastal forests on the propagation of long surface waves of small amplitude. The forest is idealized by an array of vertical cylinders. Simple models are employed to represent bed friction and to simulate turbulence generated by flow through the tree trunks. A multi-scale (homogenization) analysis similar to that for seepage flows is carried out to deduce the effective equations on the macro-scale. The effective coefficients are calculated by numerically solving the micro-scale problem in a unit cell surrounding one or several cylinders. Analytical and numerical solutions for wave attenuation on the macro-scale for different bathymetries and coastal forest configurations are presented. For a transient incident wave, analytical results are discussed for the damping of a leading tsunami. For comparison series of laboratory data for periodic and transient incident waves are also presented. Good agreement is found even though some of the measured waves are short or nonlinear.
The ice cover of the Nianchu river basin, southern Tibetan Plateau, was mapped for 2005, using a SPOT5 scene, and for 1990 and 2000 from Landsat TM/ETM. Digital elevation models (DEMs) were generated from 1 : 50 000 scale topographical maps. The results show that in 2005 there were 136 glaciers in this basin, with a total area of 224 km2. Of these, 37 glaciers had an area >1 km2 and 10 were larger than 5 km2; the average snout altitude was 5608m a.s.l. A comparison of outlines from the last 15 years shows that most glaciers have decreased in size; none have advanced. From 1990 to 2005, Xiaquepu glacier No. 56 and Shimozongpu glacier No. 38 retreated 310 and 560 m, respectively. The mean reduction in glacier surface area was 5% (10 a)–1 while the area of glacial lakes expanded by 10%; nine new lakes formed in this basin over the 15 year period. Because air temperatures here have been increasing, while precipitation has remained steady, glacier retreat is considered to be related to rising temperature.
Anatase nitrogen and fluoride codoped TiO2 sol (N–F–TiO2) catalysts were fabricated by a modified sol-gel hydrothermal method, using tetrabutyl titanate as precursor. The microstructure and morphology of sol sample were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible dielectric relaxation spectroscopy (UV-VIS-DRS), x-ray photoelectron spectroscopy (XPS), etc. It was shown that N–F–TiO2 particles in sol were partly crystallized to anatase structure and dispersed in the aqueous medium homogeneously. The average particle size was ∼12.0 nm calculated from XRD patterns, and the particle size distribution was narrow. It was noteworthy that the N–F-codoped TiO2 sol particles showed strong visible-light response and high photocatalytic activity for formaldehyde degradation under irradiation by visible light (400–500 nm); we suggested that it may result from the generation of additional band of N 2p in the forbidden band and the synergetic effect of codoping nitrogen and fluorine.
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