Immunohistochemical study on gastrointestinal endocrine cells of four reptiles

AIM: To darify the types, regional distributions and distribution densities as well as morphological features of gastrointestinal (GI) endocrine cells in various parts of the gastrointestinal track (GIT) of four reptiles, Gekko japonicus, Eumeces chinensis, Sphenomorphus indicus and Eumeces elegans.METHODS: Paraffin-embedded sections (5 μm) of seven parts (cardia, fundus, pylorus, duodenum, jejunum, ileum,rectum) of GIT dissected from the four reptiles were prepared. GI endocrine cells were revealed by using immunohistochemical techniques of streptavidin-peroxidase (S-P) method. Seven types of antisera against 5-hydroxytryptamine (5-HT), somatostatin (SS), gastrin (GAS),glucagon (GLU), substance P (SP), insulin and pancreatic polypeptide were identified and then GI endocrine cells were photomicrographed and counted.RESULTS: The GI endocrine system of four reptiles was a complex structure containing many endocrine cell types similar in morphology to those found in higher vertebrates.Five types of GI endocrine cells, namely 5-HT, SS, GAS,SP and GLU immunoreactive (IR) cells were identified in the GIT of G. japonicus, E. chinensis and S. indicus, while in the GIT of E. elegans only the former three types of endocrine cells were observed. No PP- and INS- IR cells were found in all four reptiles. 5-HT-IR cells, which were most commonly found in the pylorus or duodenum, distributed throughout the whole GIT of four reptiles. However, their distribution patterns varied from each other. SS-IR cells,which were mainly found in the stomach especially in the pylorus and/or fundus, were demonstrated in the whole GIT of E. chinensis, only showed restricted distribution in the other three species. GAS-IR cells, with a much restricted distribution, were mainly demonstrated in the pylorus and/or the proximal small intestine of four reptiles. GLU-IR cells exhibited a limited and species-dependent variant distribution in the GIT of four reptiles. SP-IR cells were found throughout the GIT except for jejunum in E. elegans and showed a restricted distribution in the GIT of G.japonicus and S. indicus. In the GIT of four reptiles the region with the highest degree of cell type heterogeneity was pylorus and most types of GI endocrine cells along the GIT showed the peak density in pylorus as well.CONCLUSION: Some common and unique features of the distribution and morphology of different types of GI endocrine cells are found in four reptiles. This common trait may reflect the similarity in digestive physiology of various vertebrates.

Two new phenylethanoid glycosides and a new secoiridoid glycoside from the roots of Picrorhiza scrophulariiflora

Two new phenylethanoid glycosides,named scroside H（1）,scroside I（2）,and a new secoiridoid glycoside,named picrogentioside I（3）,have been isolated from the underground parts of Picrorhiza scrophulariiflora.Their structures were elucidated on the basis of spectroscopic evidence.

Stability and Robust Stability of Switched Positive Linear Systems With All Modes Unstable

This paper is concerned with the stability and robust stability of switched positive linear systems(SPLSs) whose subsystems are all unstable. By means of the mode-dependent dwell time approach and a class of discretized co-positive Lyapunov functions, some stability conditions of switched positive linear systems with all modes unstable are derived in both the continuous-time and the discrete-time cases, respectively. The copositive Lyapunov functions constructed in this paper are timevarying during the dwell time and time-invariant afterwards. In addition, the above approach is extended to the switched interval positive systems. A numerical example is proposed to illustrate our approach.

Facies Architecture Model of the Shimentan Formation Pyroclastic Rocks in the Block-T Units, Xihu Sag, East China Sea Basin, and its Exploration Significance

A gas field consisting of volcanic reservoir rocks was discovered in the block-T units of the Xihu Sag,East China Sea Basin.The lithology of the volcanic rocks is dominated by tuff and reworked tuff.The lithofacies are dominated by base surge deposits of explosive facies.As the architecture model of volcanic facies is still uncertain,it has restricted the exploration and development of mineral resources in this area.Using core and cuttings data,the lithology,lithofacies,geochemistry as well as grain size characteristics of volcanic rocks were analyzed.Based on these analyses,the volcanic rocks in the well section are divided into three eruptive stages.The transport direction of each volcanic eruption is analyzed using crystal fragment size analysis.The facies architecture of the block-T units was established based on the reconstruction results of paleo-geomorphology.The results show that the drilling reveals proximal facies(PF)and distal facies(DF)of the volcanic edifices.However,the crater-near crater facies(CNCF)are not revealed.Compared with the reservoirs of the Songliao Basin,it is shown that the volcanic rocks in the Xihu Sag have good exploration potential;a favorable target area is the CNCF near the contemporaneous fault.

Germination and early seedling growth of Pinus densata Mast.provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were col- lected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distri- bution of P. densata in China to assess variation in ger- mination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germi- nated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with cli- matic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive dif- ferentiation among populations that is likely to be relevant for future afforestation.

菲律宾种植红树林的生长性能:对森林管理策略的再思考

菲律宾在恢复已消失的红树林方面做了大量工作,在过去的20年中尤为如此。鉴于此,评估这些工作的成果并把所获得的经验教训应用于目前的红树林管理便显得尤为重要。本文对几个有关评估菲律宾种植红树林的生长性能的研究项目的成果进行了综合分析。总的来说,一个普遍的趋势就是在非红树林自然生境的地方种植红树林,即把滩涂、砂坪、海草场改造成常常是由单一种类的红树属(Rhizophora)所构成的红树林。然而,在这些非红树林自然生境的地方,红树属树苗的死亡率很高。少数存活的红树属树苗(通常通过持续或多次种植)中,非自然生境和低潮间带生长的红树属幼苗个体生长缓慢;相比之下,自然生境和高潮间带生长的红树属幼苗个体生长繁茂。因此,本文认为红树林恢复过程中更合理的做法应是在红树林原来的生境,即半成水养殖池塘环境中重新种植红树林。同时,文中也探讨了相应的管理方案。当然,这些方案的最终实施与否取决于菲律宾国家和地方政府的政治意愿。

A Three-Dimensional Satellite Retrieval Method for Atmospheric Temperature and Moisture Profiles

A three-dimensional variational method is proposed to simultaneously retrieve the 3-D atmospheric temperature and moisture profiles from satellite radiance measurements. To include both vertical structure and the horizontal patterns of the atmospheric temperature and moisture, an EOF technique is used to decompose the temperature and moisture field in a 3-D space. A number of numerical simulations are conducted and they demonstrate that the 3-D method is less sensitive to the observation errors compared to the 1-D method. When the observation error is more than 2.0 K, to get the best results, the truncation number for the EOF＇s expansion have to be restricted to 2 in the 1-D method, while it can be set as large as 40 in a 3-D method. This results in the truncation error being reduced and the retrieval accuracy being improved in the 3-D method. Compared to the 1-D method, the rms errors of the 3-D method are reduced by 48% and 36% for the temperature and moisture retrievals, respectively. Using the real satellite measured brightness temperatures at 0557 UTC 31 July 2002, the temperature and moisture profiles are retrieved over a region （20°-45°N, 100°- 125°E） and compared with 37 collocated radiosonde observations. The results show that the retrieval accuracy with a 3-D method is significantly higher than those with the 1-D method.

Microfluidics-based strategies for molecular diagnostics of infectious diseases

Traditional diagnostic strategies for infectious disease detection require benchtop instruments that are inappropriate for point-of-care testing(POCT). Emerging microfluidics, a highly miniaturized, automatic, and integrated technology,are a potential substitute for traditional methods in performing rapid, low-cost, accurate, and on-site diagnoses.Molecular diagnostics are widely used in microfluidic devices as the most effective approaches for pathogen detection.This review summarizes the latest advances in microfluidics-based molecular diagnostics for infectious diseases from academic perspectives and industrial outlooks. First, we introduce the typical on-chip nucleic acid processes,including sample preprocessing, amplification, and signal read-out. Then, four categories of microfluidic platforms are compared with respect to features, merits, and demerits. We further discuss application of the digital assay in absolute nucleic acid quantification. Both the classic and recent microfluidics-based commercial molecular diagnostic devices are summarized as proof of the current market status. Finally, we propose future directions for microfluidics-based infectious disease diagnosis.

Microstructure and properties of SAF2507 superduplex stainless steel welded joints

SAF2507 plates （ 12 mm thickness ） were welded using shield metal arc welding （SMAW） process with E2594 electrode. The microstructure, o-phase, and impact fraetograph of the welded joints were analyzed using optical microscope and scanning electron mieroseope. The results show that the fusion zone consists of ferrite, chromium nitride, and secondary aastenite precipitation when welding is performed at low heat input （0. 5 kJ/mm）. However, the increase in heat input causes precipitation of brittle o＂ phase at the y/c~ interface in weld metal and heat-affected zone, as well as a brittle fracture along the grain boundary. Heat input in the range of O. 5 kJ/mm to 1.5 kJ/mm is suitable for joining SAF2507 plates.

Advances in structure and function of auxin response factor in plants

Auxin is a crucial phytohormone that has various effects on the regulators of plant growth and development.Auxin signal transduction is mainly controlled by two gene families:auxin response factor(ARF)and auxin/indole-3-acetic acid(Aux/IAA).ARFs are plant-specific transcription factors that bind directly to auxin response elements in the promoters of auxinresponsive genes.ARF proteins contain three conserved regions:a conserved N-terminal B3DNA-binding domain,a variable intermediate middle region domain that functions in activation or repression,and a C-terminal domain including the Phox and Bem1p region for dimerization,similar to theⅢandⅣelements of Aux/IAA,which facilitate protein–protein interaction through homodimerization of ARF proteins or heterodimerization of ARF and Aux/IAA proteins.In the two decades following the identification of the first ARF,23 ARF members have been identified and characterized in Arabidopsis.Using whole-genome sequencing,22,25,23,25,and 36 ARF genes have been identified in tomato,rice,wheat,sorghum,and maize,respectively,in addition to which the related biofunctions of some ARFs have been reported.ARFs play crucial roles in regulating the growth and development of roots,leaves,flowers,fruits,seeds,responses to biotic and abiotic stresses,and phytohormone signal crosstalk.In this review,we summarize the research progress on the structures and functions of ARFs in Arabidopsis,tomato,and cereal crops,to provide clues for future basic research on phytohormone signaling and the molecular design breeding of crops.

Research on two-proton radioactivity in density-dependent cluster model

The density-dependent cluster model(DDCM) provides a unified framework to study α decay,heavy-cluster radioactivity,and proton emission.Two-proton(2p) radioactivity is a rare decay mode of exotic nuclei near or beyond the drip-line.It is of great interest to explore the applicability of DDCM to this exotic decay mode.In this work,DDCM has been extended to study 2p radioactivity.The 2p-radioactivity half-lives are calculated for several known 2p-emitters,including19Mg,45Fe,48Ni,54Zn,and67Kr.The theoretical results are in good agreement with the experimental data,with the standard deviations comparable to or smaller than those given by some other theoretical models and empirical formulas.We also predict the half-lives of a number of possible 2p-emitters with S2p<0 and Sp> 0 using the new data from AME2020 and NUBASE2020.These predictions serve as useful references for future experimental and theoretical investigations on 2p radioactivity.

Nano-silver-modified polyphosphazene nanoparticles with different morphologies:Design,synthesis,and evaluation of antibacterial activity

Drug-resistant bacteria present a severe threat to public health,emphasizing the importance of developing broad-spectrum antibacterial agents that are free from drug resistance.Among silver-based antibacterial agents,nano-silver has been found to exhibit the most promising and comprehensive performance.The exploration of the antibacterial capacity and morphological changes of silver nanoparticles(AgNPs)could offer a starting point for the development of safe and efficient antibacterial agents.In this study,three types of nano-silver-modified polyphosphazene(PRV)nanoparticles with different morphologies were synthesized using precipitation polymerization.These nanoparticles were characterized using various techniques,including Fourier-transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and thermogravimetric analysis(TGA).The antibacterial activity of these nanoparticles against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)was assessed using minimum inhibitory concentration(MiC)/minimum bactericidal concentration(MBC)tests and inverted fluorescence microscopy.Our results revealed that the antibacterial activity of silver nanoparticles can vary significantly depending on their immobilized form.Ag@PRV Strawberry-like nanoparticles(NPs)exhibited higher antibacterial activity compared to Ag@PRV Yolk-Shell NPs and Ag@PRV Cable-like nanofibers(NFs).Notably,all three types of synthesized nanoparticles demonstrated a stronger bactericidal effect on Gram-positive bacteria than Gram-negative bacteria.Live/dead bacterial staining and scanning electron microscopy demonstrated that silver can kill bacteria by altering the permeability of their cell membranes.These findings offer valuable insights for designing and practically applying new silver-based antibacterial agents in the future.

Detection of congenital cytomegalovirus in newborns using nucleic acid amplification techniques and its public health implications

Human cytomegalovirus(HCMV), a herpesvirus, is an important human pathogen that causes asymptomatic infections in healthy or immunocompetent individuals but can lead to severe and potentially life-threatening complications in immune-immature individuals such as neonates or immune-compromised patients such as organ-transplant recipients and HIV-positive individuals.Congenital HCMV infection represents a significant public health issue and poses substantial healthcare and economic burden to society. This virus causes the most common viral congenital infection worldwide, and is the leading non-genetic cause of sensorineural hearing loss in children in developed countries. Congenital HCMV infection is believed to fulfill the criteria of the American College of Medical Genetics to be considered as a condition targeted for a newborn screening program. This is because congenital HCMV infection can be identified during a time(within 2 days after birth) at which it would not ordinarily be detected clinically, and there are demonstrated benefits of early detection, timely intervention, and efficacious treatment of the condition. Recent progresses in developing polymerase chain reaction-based approaches to detect HCMV in samples obtained from newborns have generated much excitement in the field. In this review, we highlight the recent progress in diagnostic techniques that could potentially be used for the detection of HCMV infection in neonates and its direct implications in public health settings for diagnosing congenital HCMV infection.

Connecting scales： Achieving in-field pest control from areawide and landscape ecology studies

Areawide management has a long history of achieving solutions that target pests; however, there has been little focus on the areawide management of arthropod natural enemies. Landscape ecology studies that show a positive relationship between natural enemy abundance and habitat diversity demonstrate landscape-dependent pest suppression, but have not yet clearly linked their findings to pest management or to the suite of pests associated with crops that require control. Instead the focus has often been on model systems of single pest species and their natural enemies. We suggest that management actions to capture pest control from natural enemies may be forth coming if： （i） the suite of response and predictor variables focus on pest complexes and specific management actions; （ii） the contribution of＂the landscape＂ is identified by assessing the timing and numbers of natural enemies immigrating and emigrating to and from the target crop, as well as pests; and （iii） pest control thresholds aligned with crop development stages are the benchmark to measure impact of natural enemies on pests, in turn allowing for comparison between study regions, and generalizations. To achieve pest control we will need to incorporate what has been learned from an ecological understanding of model pest and natural enemy systems and integrate areawide landscape management with in-field pest management.

A Triple Crosslinking Design toward Epoxy Vitrimers and Carbon Fiber Composites of High Performance and Multi-shape Memory

It remains a challenge to use a simple approach to fabricate a multi-shape memory material with high mechanical performances.Here,we report a triple crosslinking design to construct a multi-shape memory epoxy vitrimer(MSMEV),which exhibits high mechanical properties,multi-shape memory property and malleability.The triple crosslinking network is formed by reacting diglycidyl ether of bisphenol F(DGEBF)with 4-aminophenyl disulfide,γ-aminopropyltriethoxysilane(APTS)and poly(propylene glycol)bis(2-aminopropyl ether)(D2000).The triple crosslinking manifests triple functions:the disulfide bonds and the silyl ether linkages enable malleability of the epoxy network;the silyl ether linkages impart the network with high heterogeneity and broaden the glass transition region,leading to multi-shape memory property;a small amount of D2000 increases the modulus difference between the glassy and rubbery states,thereby improving the shape fixity ratio.Meanwhile,the high crosslinking density and rigid structure provide the MSMEV with high tensile strength and Young’s modulus.Moreover,integrating carbon fibers and MSMEV results in shape memory composites.The superior mechanical properties of the composites and the recyclability of carbon fiber derived from the dissolvability of MSMEV make the composites hold great promise as structural materials in varied applications.

Regulation of gelsolin to plant actin filaments and its distribution in pollen

The effect of plasma gelsolin on plant microfilaments and its localization in plant cells were investigated. The results by using ultracentrifugation and electron microscopy showed that plant microfilaments could be severed into shorter fragments by gelsolin in a Ca2+-dependent manner. By measuring the binding ability of plasma gelsolin to pollen actin using the method of immunoprecipitation, it was shown that pollen actin could bind gelsolin at a ratio of 2.0±0.21 in the presence of Ca2+. Addition of EGTA could disassociate the actin-gelsolin complexes, reducing the ratio to 1.2±0.23, and the addition of PIP2 could further reduce the ratio to 0.8±0.1. The results indicate that plant actin has similar binding properties with plasma gelsolin as that of animal actin. By Western blotting we identified the existence of gelsolin in lily pollen. The results of immunolo- calization of gelsolin in pollen and pollen tube showed that gelsolin was mainly localized at the germinal furrow in pollen grains and at the cytoplasm in pollen tube, especially in the tip region.

Flame-retardant and Self-healing Biomass Aerogels Based on Electrostatic Assembly

It remains a significant challenge to fabricate self-healing aerogels with excellent flame retardancy.Herein,we develop a class of biomass aerogels by electrostatically assembling chitosan(CS),phytic acid(PA),and itaconic acid(IA).The electrostatic interaction between CS and IA is weak and dynamic,so freeze-drying the solution of CS and IA enables the formation of continuous aerogel skeleton with self-healing ability and re-programmability;in comparison,the electrostatic interaction between CS and PA is strong and less dynamic,and thus mixing PA with CS in aqueous solution leads to fine precipitates of high flame retardancy due to the synergistic phosphorus-nitrogen effect.Integrating the continuous skeleton and the fine precipitates results in self-healing aerogles with UL-4 V-0 rating of flame retardancy aerogels and autoextinguishable feature.Interestingly,the aerogels after burning in flame for 30 s form a skin-core structure,and the carbonized skin protects the integrity of the aerogels and the self-healing ability of the internal parts.Therefore,this work provides a facile strategy to develop multifunctional aerogels which hold great promise for advanced applications.

Population dynamics inside cancer biomass driven by repeated hypoxia-reoxygenation cycles

A computational analysis of genome-scale transcriptomic data collected on -1,700 tissue samples of three cancer types： breast carcinoma, colon adenocarcinoma and lung adenocarcinoma, revealed that each tissue consists of （at least） two major subpopulations of cancer cells with different capabilities to handle fluctuating Oz levels. The two populations have distinct genomic and transcriptomic characteristics, one accelerating its proliferation under hypoxic conditions and the other proliferating faster with higher O2 levels, referred to as the hypoxia and the reoxygenation subpopulations, respectively. The proportions of the two subpopulations within a cancer tissue change as the average 02 level changes. They both contribute to cancer development but in a complementary manner. The hypoxia subpopulation tends to have higher proliferation rates than the reoxygenation one as well as higher apoptosis rates; and it is largely responsible for the acidic environment that enables tissue invasion and provides protection against attacks from T-cells. In comparison, the reoxygenation subpopulation generates new extracellular matrices in support of further growth of the tumor and strengthens cell-cell adhesion to provide scaffolds to keep all the cells connected. This subpopulation also serves as the major source of growth factors for tissue growth. These data and observations strongly suggest that these two major subpopulations within each tumor work together in a conjugative relationship to allow the tumor to overcome stresses associated with the constantly changing Oz level due to repeated growth and angiogenesis. The analysis results not only reveal new insights about the population dynamics within a tumor but also have implications to our understanding of possible causes of different cancer phenotypes such as diffused versus more tightly connected tumor tissues.

Non-viral gene delivery carrier of probe ty[pe host molecule--Interactions between DNA and β-cyclodextrin derivative complexes(I)

A host type non-virus gene delivery car- rier, phenanthroline-β-cyclodextrin derivative host molecule, was produced which can be used as mo- lecular probe. Interactions between DZY-1 and DNA were investigated by electrophoresis assay. Hind III enzyme inhibition assay was carried out using DNA condensates induced by host molecules or host- guest molecule complexes to explore their ability to inhibit enzyme digestion. Micro-structure of DNA condensates induced by host molecules and host-guest molecule complexes was observed by scanning electron microscope (SEM). Our work in- dicates the delivery mechanism of DZY-1 used as a gene delivery carrier and also provides a method to design and produce non-virus gene delivery carriers.

克隆整合影响严重光胁迫下第一分株世代的生长和沉积物特征但不影响后续分株世代的生长和沉积物特征

克隆整合通过缓冲环境压力和提高资源获取效率使克隆植物受益。然而,在一个克隆系统中,受益于克隆整合的连接分株世代的数量很少受到关注。我们进行了一个盆栽实验来评估沉水植物苦草(Vallisneria natans)克隆系统内的生理整合程度,该克隆系统由一个母株和3个依次连接的后代分株组成。母株生长在正常光照下,而后代分株被严重遮荫。母株与后代分株间的匍匐茎被切断或保持连接,但3个后代分株之间的连接仍然存在。与遮荫的后代分株连接时,苦草未遮荫的母株的光合能力显著增强,但其生物量积累大大减少。克隆整合显著增加了第一分株世代(相邻分株)的生物量积累和土壤的碳氮可用性、胞外酶活性和微生物生物量,但没有增加后续分株世代的这些特征。我们的结果表明,在严重光胁迫下,来自苦草母株的支持可能仅限于克隆系统中相邻的后代分株,这暗示着一个分株世代的效应。我们的结果有助于更好地理解克隆植物的层次结构和分段化。这些发现表明克隆整合程度在分株种群的生态相互作用中起着至关重要的作用。