Provenance Analysis in the Nima Basin during Paleogene and Its Implications for the Decline of the Tibetan Central Valley

It is unclear what caused the Bangong Nujiang suture zone in the central Tibetan plateau to rise from less than 2 km in early Cenozoic to more than 4 km at present. The zircon U-Pb ages and trace elements of samples from the Niubao Formation in the Paleogene of the Nima basin were analyzed and tested. Combined with the isostasy theory, the surface uplift height of the Nima Basin during the Cenozoic period was calculated. The zircon U-Pb age results of the Niubao formation are consistent with the ages of the Lhasa terrane on the south side of the basin, the Qiangtang terrane on the north side, and the uplift in central. The zircon Eu/Eu* results show that the crust in central part of Tibetan plateau thickened by ∼20 km in Paleogene, resulting in ∼3 km surface uplift. Sediments created a total of about 1 km of surface uplift throughout the Paleogene, and the deposition rate began to slow down significantly at ∼40 Ma. Therefore, it is inferred that in the early Cenozoic, the uplift of the valley was mainly caused by sedimentation. With the continuous downward subduction of the Indian plate, at about 40 Ma, factors such as crustal shortening dominated the uplift of the central valley, and the uplift caused by deposition only accounted for a very small part. In general, the uplift of the Central Valley in the Paleogene was mainly affected by crustal shortening, but a quarter of the surface uplift was caused by the accumulation of sediments.

Changes in the Microbial Community in Maize (Zea mays L.) Root Spatial Structure Following Short-Term Nitrogen Application

The beneficial interactions between crop roots and microbiomes play a key role in crop nutrient availability, growth promotion, and disease suppression. Recent research, however, rarely reported the effects of nitrogen (N) application rate on microbial community composition at different spatial structures in the maize root zone. Therefore, one experiment was conducted to examine the influence of three N-application levels (0, 180, and 360 kg N ha^-1) on microbial community composition in three root-associated compartments of maize (bulk soil, rhizoplane, and endosphere). The microbial diversity and community composition differed significantly among the various compartments. The effects of N application on fungal composition decreased in the order bulk soil > rhizosphere > endosphere at different sampling positions. Also, the fungal composition was more sensitive to the N-fertilizer rate in the bulk soil and the rhizosphere than the bacterial community. A total of 14.42, 9.46, and 3.55% of all taxonomic groups were sensitive to N fertilizer, respectively. The keystone species fungal groups were Humicola (bulk soil), Gibberella (rhizosphere soil), and Humicola (endosphere). Together, our results demonstrate that compared with that of the bacterial community, the fungal community composition was more susceptible to different N-application rates. N fertilization affected the distribution of microflora by changing soil physicochemical properties and enzyme activities. There were strong correlations between microbial communities in maize under the N180 treatment. Moreover, the N180 treatment had the maximum fresh yield and biomass at 64.5 and 24.3 kg·ha^-1, respectively.

Effect of Benzyl Alcohol on Biomethanation from Lignite

Currently, biomethane obtained from coal resources, such as lignite and peat, serves as a sustainable biofuel urgently needed by the energy economy. To improve biomethane yield from lignite, the effects of different concentrations of benzyl alcohol, a degraded product of humic acid, on a biomethanation fermentation system were analyzed. The total biomethane yield, daily biomethane yield, coenzyme F₄₂₀, VFA (volatile fatty acids) concentration, alkalinity, and pH were used to determine the optimal benzyl alcohol concentration. The biomethanation fermentation system with 2000 mg/L benzyl alcohol produced up to 4.03 mL/g of biomethane, which was 1.15 times that produced from the control group. The coenzyme F₄₂₀, VFA, alkalinity, and pH of the system after adding 2000 mg/L benzyl alcohol were more preferable after adding other concentrations during the lignite biomethanation process. In summary, 2000 mg/L benzyl alcohol had a significantly positive effect on the lignite biomethanation fermentation system. When benzyl alcohol is added to the fermentation system, it accelerates the tricarboxylic acid cycle, which in turn produces more biomethane. Additionally, the self-supply of lignite microbial transformation nutrients from the perspective of chemical composition was explored as a novel approach in solving the common problem of low biomethane yield from a single lignite raw material. This also laid a foundation for subsequent steps through the adjustment of pretreatment conditions to ensure that the lignite pretreatment liquid contained increased benzyl alcohol, and a greater yield of biomethane can be produced after activated sludge addition.

Unprecedented Prediction of a B160 Cluster Stuffed by Dual-Icosahedron B12

Serving as the premise to understand bulk allotropes, boron clusters have been intriguing experimentalists and theoreticians to study their geometries and chemical bonding. Here, we designed a complete core-shell B₁₆₀ cluster stuffed by two B₁₂ cores, which is energetically preferable over the bilayer structure of the same size. The unprecedented peanutlike structure with C_i symmetry has superior stability and exhibits superatomic electronic configuration and spherical aromaticity. Our theoretical work not only proposed the core-shell structure of dual icosahedrons for the first time but also indicated the multi-B₁₂ core-shell structural pattern in boron particles, bridging to boron crystalline structures.

Molecular Dynamics Study on the Compatibility of Asphalt and Rubber Powder with Different Component Contents

In order to study the influence of asphalt from different origins on the compatibility of rubber powder and asphalt, the four most representative 90# asphalts from different origins were selected for the four-component test, namely, Karamay, Shell, Esso, and HuanxiLing, which have differences in their microstructure and molecular structure. First, Materials Studio software was used to build the asphalt molecular model based on the four-component test data, and styrene butadiene rubber and natural rubber were used as representative molecules of rubber powder to build the molecular model. The solubility parameters, molecular potential energy, and radial distribution function were obtained by molecular dynamics simulation of rubber powder and four asphalt molecules. The gray correlation degree analysis of the four components of asphalt is carried out with the gray correlation method. The results show that the solubility parameter difference between Esso asphalt and the rubber molecule is the smallest, and the potential energy between them is the largest; that is, the compatibility between Esso asphalt and rubber powder is the best, followed by Shell, Huanxiling, and Karamay. The analysis of the radial distribution function between two molecules also further confirmed the compatibility of the four modified asphalt. The gray correlation degree between the four components of asphalt and the solubility and molecular potential energy index is as follows: saturates > aromatics > resin > asphaltene. It is concluded that the influence of light components on the compatibility of asphalt is greater than that of heavy components. Therefore, in future industrial production, the rubber powder-modified asphalt made of more light components has better performance and storage stability.

Theoretical Insights into the Geometrical Evolution, Photoelectron Spectra, and Vibrational Properties of YGe n - (n = 6-20) Anions: From Y-Linked to Y-Encapsulated Structures

The structural evolution behavior of germanium anionic clusters doped with the rare-earth metal yttrium, YGe _n ^- (n = 6-20), has been investigated using a mPW2PLYP density functional scheme and an ABCluster structure searching technique. The results reveal that with increasing cluster size n, the structure evolution pattern is from the Y-linked framework (n = 10-14), where Y serves as a linker (the Y atom bridges two germanium subclusters), to the Y-encapsulated framework (n = 15-20), where the Y atom is located in the center of the Ge cage. The simulated PES spectra show satisfying agreement with the experimental PES spectra for n = 12-20, which reveals that the global minimum structures reported here are reliable. In particular, the anionic YGe₁₆ ^- nanocluster is found to be the most stable structure in the size range of n = 6-20 through analyzes of the relative stability, highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap, spherical jellium model, and isochemical shielding surface. Moreover, spectral properties such as infrared and Raman spectra were reported. In addition, the UV-vis spectra of the YGe₁₆ ^- nanocluster are in good agreement with solar energy distribution, showing that such substances serve as multifunctional building blocks to be potentially used in optoelectronic devices or solar energy converters.

Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate Catalyzed by a Deep Eutectic Solvent

In this study, the alcoholysis of furfuryl alcohol (FA) into ethyl levulinate (EL) using a deep eutectic solvent (DES) composed of choline chloride (ChCl) and ethanol was investigated by experiments and calculations. Experimental results reveal that the addition of 5-sulfonic acid salicylic acid (5-SSA) can catalyze the alcoholysis of FA to produce EL. The combined presence of ChCl and 5-SSA significantly improved the selectivity for EL. The mechanism of the alcoholysis of FA to EL in acidic DES was investigated by density functional theory (DFT) calculations in Gaussian 03. It was found that hydrogen-bond acceptor ChCl is coupled with hydrogen-bond donor ethanol to form a structure similar to HCl and ethoxy, which facilitates the alcoholysis of FA into EL.

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

In this work, the isomer mixture of 4,4'-diphenylmethane diisocyanate (MDI) and 2,4'-MDI was separated and purified by dynamic falling film melt crystallization, and 99.3% purity and 50.8% yield of 4,4'-MDI could be obtained under optimized conditions. The separation mechanism was simulated by density functional theory (DFT) and molecular dynamics (MD) simulation. Results showed that compared with 2,4'-MDI, 4,4'-MDI molecules could form a more stable and symmetrical crystal structure due to their stronger charge density symmetry and electrostatic potential energy. Furthermore, the separation phenomenon and the formation of the crystal structure were observed according to the radial distribution function (RDF) and orientation correlation function obtained from MD simulation. Finally, the attachment energy (AE) model was used to observe and compare different crystal surfaces; it was proposed that the aggregation of 4,4'-MDI was attributed to the polar attraction between isocyanate groups according to the results of the orientation correlation function. It was also observed that compared with 2,4'-MDI, 4,4'-MDI molecules on the (110) crystal surface were easier to form crystal structures.

Supported Bimetallic Trimers Fe2M@NG: Triple-Atom Catalysts for CO2 Electroreduction

Excessive accumulation of carbon dioxide in the atmosphere has become a serious environmental problem due to the increasing consumption of fossil fuels in modern society. Reasonably reducing CO₂ in the atmosphere has become a new research hotspot. Electrocatalytic CO₂ reduction reaction (CO₂RR) offers an appealing strategy to reduce the atmospheric CO₂ concentration and to produce value-added chemicals simultaneously. In this paper, two-dimensional (2D) N-decorated graphene (NG)-supported bimetallic trimers (Fe₂M@NG) were designed as triple-atom catalysts (TACs). Theoretical calculations showed that Fe₂M@NG can effectively activate CO₂, and among the 23 TACs examined, Fe₂Ir@NG not only has a good catalytic activity for CO₂RR (limiting potential is 0.49 V for CH₄ formation) but also limits the competing side reaction of the hydrogen evolution reaction (HER). Our theoretical study not only further extends the triple-atom catalysts, but also opens a new door to boost the sustainable CO₂ conversion.

Water-Tolerant Boron-Substituted MCM-41 for Oxidative Dehydrogenation of Propane

Boron-based catalysts for oxidative dehydrogenation of propane (ODHP) have displayed excellent olefin selectivity. However, the drawback of deboronation leading to catalyst deactivation limited their scalable applications. Hereby, a series of mesoporous B-MCM-41 (BM-x, B/Si = 0.015-0.147) catalysts for ODHP were prepared by a simple hydrothermal synthesis method. It was found that propane conversion was increased and the initial reaction temperature was reduced with an increase of boron content, and the optimal values appeared on BM-2.0 (B/Si = 0.062), while olefins' (ethylene and propylene) selectivity was maintained at ca. 70-80%. Most importantly, BM-1.0 (B/Si = 0.048) exhibited favorable activity, stability, and water tolerance after washing treatment or long-time operation (e.g., propane conversion of ca. 15% and overall olefin selectivity of ca. 80% at 550 °C) because its high structural stability prevented boron leaches. These features were identified by X-ray diffraction (XRD), N₂ physisorption, inductively coupled plasma-mass spectrometry (ICP-MS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy studies. The tri-coordinated B-OH species incorporated into the mesoporous silica framework are considered to be the active sites for ODHP.

Thermogravimetric analysis of the pyrolysis and combustion kinetics of surface dead combustibles in the Daxing'an Mountains

In boreal regions, the frequency of forest fires is increasing. In this study, thermogravimetric analysis was used to analyze the pyrolysis kinetics of dead surface combustibles in different forest types within the Daxing'an Mountains, China. The results show that the combustible material load of forest types, the Larix forest (LG) is relatively high. Base on the E of kinetic parameters, the LG, and Quercus forest (QM) forest types had relatively high combustibility values and comprehensive combustibility values for 1-, 10-, and 100-h time lags. According to the obtained P values, the pyrolysis of dead surface fuels with 1-, 10-, and 100-h time lags is relatively difficult in the Larix / Betula mixed forest (L-B) and QM forest types. Therefore, mixed forests of the LG, L-B, and QM tree species can be established as fire-resistant forests to establish a fire barrier, reduce the combustibility of forest stands, and reduce the possibility of forest fires.

Molecular Simulation Study on the Interaction between Tyrosinase and Flavonoids from Sea Buckthorn

Isorhamnetin, kaempferol, myricetin, and quercetin are four kinds of secondary metabolites in sea buckthorn, which have a wide range of biological activities. Investigating their interactions with tyrosinase at the atomic level can improve the bioavailability of sea buckthorn. Both molecular docking and molecular dynamics simulation methods were employed to study the interactions of these ligands with tyrosinase. The results of molecular docking indicated that these four small molecules such as isorhamnetin, kaempferol, myricetin, and quercetin can all dock into the active center of tyrosinase, and by occupying the active site, they can prevent substrate binding, thereby reducing the catalytic activity of tyrosinase. Molecular dynamics simulation trajectory analysis showed that all tyrosinase-ligand complexes reach an equilibrium within 100 ns. In addition, quercetin has the lowest binding energy among these four ligands, and the complex with tyrosinase is the most stable. This study not only provides valuable information for improving the bioavailability of sea buckthorn but also contributes to the discovery of effective natural inhibitors of tyrosinase.

Ethnobotanical profiles of wild edible plants recorded from Mongolia by Yunatov during 1940-1951

Mongolian traditional botanical knowledge has been rarely researched concerning the ethnobotany theory and methodology in the last six decades (Pei in Acta Botanica Yunnanica 135-144, 1988, as reported (Martin in Ethnobotany: A methods manual, Chapman and Hall, 1995)). However, most of the known literature of indigenous knowledge and information regarding the use of local wild plants among Mongolian herders was first documented by several botanical research of Russian researchers in Mongolia through the 1940s and 1950s. One of the most comprehensive works was completed by A. A. Yunatov (1909-1967), which is known as "Fodder Plants of Pastures and Hayfields of the People's Republic of Mongolia" (FPM). Yunatov's research sampled forage plants in Mongolia from 1940 to 1951 and subsequently published a study in 1954. The original transcript of FPM was later translated into Chinese and Mongolian (Cyrillic alphabet) during 1958 and 1968. In addition to morphological characteristics, distribution, habitat, phenology, palatability, and nutrition of forage plants, Yunatov`s record collected local names, the folk understanding and evaluation of the forage, as well as other relevant cultural meanings and the use of local wild plants (collected from the wild as opposed to cultivated plants) in FPM through interviews. The book contains the most precious records created in the 1940s and 1950s on folk knowledge of the Mongolians' wild plants in Mongolia. It was composed of 8 chapters and 351 pages in total. The fifth chapter of FPM, entitled "The systematic overview of forage plants," making up 272 pages (77.49% of the total page counts). The order and content of the book-oriented along with profiles of specific plants. Yunatov collected detailed information on plants, such as the local name, morphology, distribution, habitats, ecological characteristics, and phenology. He also discussed the palatability of livestock, particular forage use, other usages, and chemical composition. Through careful reading and understanding of all three versions of the book (in Russian, Chinese, and Mongolian (Cyrillic alphabet)), the FPM-listed information of edible plants was categorized using ethnobotanical dependent analysis. The list of edible plants was ranked based on purposes and ethnobotanical inventories as per methodology and analysis used in the ethnobotany research. FPM listed 35 species are part of 15 families and 25 genera of wild edible plants. Most species belong to Liliaceae and Allium. Naturally grown grain and some food substitutes (plants that could be used as substitutions for typical food) come from the starchy organs, such as seeds, bulbs, roots, and rhizomes of 12, accounting for 34.28% of all species. Wild vegetables come from the parts of a young plant, tender leaves, young fruits, lower leg of stems, and bulbs of 9 species, accounting for 25.71% of all species. There are only three species of wild fruits, accounting for 8.57% of all edible plant species. Tea substitutes consist of leaves, roots, follicle, and aboveground parts of 8 wild plant species, accounting for 22.85% of all species. Seasonings from the wild were made of the elements such as seeds, rhizomes, tender leaves of 7 species, accounting for 20.00% of all species (Fig,8). Similarities and differences are noticeable in utilizing wild edible plants among Mongolian populations living in Mongolia and Inner Mongolia. Six species of wild edible plants listed in FPM have been proven to be collected and consumed by Mongolians from the Genghis Khan era in the twelfth century to the present day. This proved that the Mongolians have a tradition of recognizing and utilizing wild plants, demonstrating historical and theoretical value. Seven species of plants mentioned in this book were closely correlated to the locals' processing of traditional dairy products, meat, and milk food. Yunatov was not an ethnobotanist, but his accurate documentation of interviews and surveys with Mongolians represents valuable information about the collection and consumption of local wild plants during 1940-1951 in Mongolia. His research mission meant to focus on forage grass, the feed plant that sustained livestock, while he also recorded plants consumed by humans. His records on the edible parts and intake methods of some plants are incomplete. Still, it provided ethnobotanical materials of a remarkable scientific value and a living history of ethnobotany in Mongolian regions. Even by today`s standards, it will be challenging to obtain first-hand information of the richness and to the extent of Yunatov's research.

Analysis of sagittal curvature and its influencing factors in adolescent idiopathic scoliosis

ABSTRACT

This study aimed to explore the characteristics of changes in the sagittal arrangement of the spine between adolescent patients with idiopathic scoliosis (AIS) and normal adolescents, the risk factors for AIS and the factors affecting the progress of AIS.X-ray images of the full length of the spine in standing position were taken in AIS patients and normal adolescents. Radiographic measurements made at intermediate follow-up included the following:C1 and C2 cervical lordosis and C2 - C7 curvature of cervical lordosis, C2-C7sagittal horizontal distance (C2-C7SagittalVerticalAxis, C2-C7SVA), TS-CL, after thoracic lobe (Thoracic Kyphosis, TK), thoracic lumbar segment Angle (thoracolumbar kyphosis, [TLK]), lumbar lordosis Angle (Lumbar Lordosis, LL), sacral slope Angle (Sacrum Slope, SS), pelvic tilt Angle (Pelvic Tilt, PT), pelvic incidence (PI), L5 Incidence (Lumbar5 Slope (L5S), L5 incidence (Lumbar5 Incidence (L5I), sagittal horizontal distance (CSVA), lower depression Angle of the 2nd cervical spine. The difference of sagittal plane parameters between AIS group and normal adolescent group was compared. To evaluate the progress of AIS, correlation analysis was conducted between diagonal 2 and other parameters. The main risk factors of AIS were determined by binary Logistic analysis.The CSVA of AIS patients was higher than that of healthy adolescents (AIS: 27.64 ± 19.56) mm. Healthy adolescents: (17.74 ± 12.8) mm), L5S (AIS: 19.93°= 7.07° and healthy adolescents: 15.38°= 7.78°, P = .024 < .05), C2 downward sag Angle (AIS: 15.12°= 2.7°;Healthy adolescents: 12.97°= 4.56°); AIS patients had lower TS-CL (AIS: 22.48 ± 6.09 and healthy adolescents: 28.26°= 10.32°), PT (AIS: 10.42°= 4.53° and healthy adolescents: 15.80°=7.68°), (AIS: 41.87°=9.72° and healthy adolescents: 48.75°= 8.22°). The main risk factor for idiopathic scoliosis in adolescents was L5 (OR = 1.239, 95%CI = 1.049-1.463, P = .012 < .05).L5S is a major risk factor for idiopathic scoliosis in adolescents. The larger PI is, the higher the risk of scoliosis progression is. In AIS patients, lumbar lordosis is increased, cervical lordosis is reduced, and even cervical kyphosis occurs.

Electro-synthesized Co(OH)2@CoSe with Co-OH active sites for overall water splitting electrocatalysis

Constructing noble metal-free electrocatalytically active sites for the simultaneous hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution is key to realizing electricity-driven water splitting in practical applications. Here, we rationally designed Co(OH)₂@CoSe nanorods (NRs) as an excellent bifunctional electrocatalyst by an in situ electrochemical transformation strategy, where the Co-based nanorod template was converted into Co(OH)₂@CoSe at the cathode. The obtained electrode exhibits superior electrocatalytic activity for both the HER (overpotential of 208 mV at 20 mA cm^-2) and the OER (268 mV at 20 mA cm^-2) at high current density in a 1 M KOH solution. The theoretical calculations and experimental evidence indicate that the chemical coupling Co-OH active site between Co(OH)₂ and CoSe regulates the hydrogen adsorption and desorption energy and fast electron transfer capability, which is responsible for the improved HER. Moreover, the Co(OH)₂@CoSe NRs can be further converted into CoOOH nanosheets which serve as OER active sites. Toward practical electrolytic cell applications, the Co(OH)₂@CoSe nanorods as both the cathode and anode achieved a current density of 100 mA cm^-2 at 1.94 V for overall water splitting, better than that of noble metal-based electrocatalysts.

Functionalized biochar-supported magnetic MnFe2O4 nanocomposite for the removal of Pb(ii) and Cd(ii)

In this study, a novel magnetic biochar-MnFe2O4 nanocomposite (BC/FM) was prepared using low-cost corn straw and MnFe2O4 by sol-gel/pyrolyzing route using egg white, which has abundant functional groups (-NH2 and -COOH). Following that, its composition, morphology and structure was characterized by various techniques including SEM-EDX, BET, XRD, and VSM. Batch experiment of the adsorption for Pb(ii) and Cd(ii) including influence of pH, kinetics, isotherm and thermodynamics was also studied. The results demonstrated that biochar could effectively support MnFe2O4, which displayed high dispersion on the surface of the biochar and possessed abundant functional groups and high surface area contributing to superior performance on Pb(ii) and Cd(ii) removal. Therein, MnFe2O4 with high magnetism is convenient for separating the magnetic BC/FM from an aqueous medium. Adsorption experiment results indicate that Pb(ii) and Cd(ii) removal by BC/FM was closely related to pH with the best value of pH 5.0, and the process reached equilibrium in 2 h. The adsorption process is well-described by the pseudo-second-order kinetic model and Sips (Freundlich-Langmuir) model. Thermodynamic studies suggest that the adsorption process is spontaneous and exothermic. The maximum experimental adsorption capacity of BC/FM is 154.94 and 127.83 mg g-1 for Pb(ii) and Cd(ii), respectively, in single-solute system, which is higher than that of some of the other adsorbents of biochar or biochar-based composites. In bi-solute system, the preferential adsorption order of BC/FM for the two metals is Pb(ii) prior to Cd(ii). Finally, FTIR and XPS analysis verified that the main mechanism of Pb(ii) and Cd(ii) removal by BC/FM is by forming Pb/Cd-O or complexation of carboxyl and hydroxyl and ion exchange. Therefore, the prepared magnetic BC/FM composite, as an excellent adsorbent, exhibited potential applications for the removal of Pb(ii) and Cd(ii) from wastewater.

Multiwall-carbon-nanotube/cellulose composite fibers with enhanced mechanical and electrical properties by cellulose grafting

Multiwall-carbon-nanotube (MWCNT)-cellulose/cellulose composite fibers with promoted mechanical and electronic activities were synthesized. Remarkably, the dispersion of MWCNTs in the composite fibers was facilitated through cellulose grafting, resulting in the tensile strength of the obtained MWCNT-cellulose/cellulose composite fibers being increased to 304.6 MPa with 10 wt% MWCNTs involved, which was almost 106.8% higher than that of pristine MWCNT/cellulose fibers with the same amount of MWCNTs. In addition, the electrical conductivity of the MWCNT-cellulose/cellulose composite fibers was enhanced to 1.3 × 10-1 S cm-1 with the dispersion of 10 wt% MWCNTs, which was almost 108 times higher than that of pristine MWCNT/cellulose fibers with the same amount of MWCNTs.

Epithelial stem cells are formed by small-particles released from particle-producing cells

Recent spatiotemporal report demonstrated that epidermal stem cells have equal potential to divide or differentiate, with no asymmetric cell division observed. Therefore, how epithelial stem cells maintain lifelong stem-cell support still needs to be elucidated. In mouse blood and bone marrow, we found a group of large cells stained strongly for eosin and containing coiled-tubing-like structures. Many were tightly attached to each other to form large cellular clumps. After sectioning, these large cell-clumps were composed of not cells but numerous small particles, however with few small "naked" nuclei. The small particles were about 2 to 3 μm in diameter and stained dense red for eosin, so they may be rich in proteins. Besides the clumps composed of small particles, we identified clumps formed by fusion of the small particles and clumps of newly formed nucleated cells. These observations suggest that these small particles further fused and underwent cellularization. E-cadherin was expressed in particle-fusion areas, some "naked" nuclei and the newly formed nucleated cells, which suggests that these particles can form epithelial cells via fusion and nuclear remodeling. In addition, we observed similar-particle fusion before epithelial cellularization in mouse kidney ducts after kidney ischemia, which suggests that these particles can be released in the blood and carried to the target tissues for epithelial-cell regeneration. Oct4 and E-cadherin expressed in the cytoplasmic areas in cells that were rich in protein and mainly located in the center of the cellular clumps, suggesting that these newly formed cells have become tissue-specific epithelial stem cells. Our data provide evidence that these large particle-producing cells are the origin of epithelial stem cells. The epithelial stem cells are newly formed by particle fusion.

Field Sandbur (Cenchrus pauciflorus) Seeds in the Same Bur Respond Differently to Temperature and Water Potential in Relation to Germination in a Semi-Arid Environment, China

The success of a biological invasion relies on the environment and is closely linked to factors such as water and temperature. Invasive plant species display different seed characteristics, including shape. Field sandbur (Cenchrus pauciflorus) is a globally widespread invasive species capable of adapting to broad environmental conditions. However, its germination response to water and temperature still remains unclear. C. pauciflorus contains two seeds in the same bur that differ in size: big seeds (M) and small seeds (P). Separate greenhouse experiments were conducted under different temperature regimes (0/10°C, 5/15°C, 10/20°C, 15/25°C, 18/28°C, 20/30°C and 25/35°C) and water potentials (-1.50Mpa, -1.00Mpa, -0.75Mpa, -0.50Mpa, -0.25Mpa and 0Mpa) for M and P seeds. The results support the hypothesis that germination of C. pauciflorus is significantly influenced by seed type, temperature and water potential. M and P seeds responded differently to varied alternative temperatures and water potentials. However, M and P seeds were more sensitive to water potential than to temperature. Optimal conditions for M and P seed germination were measured at 25/35°C (night temperature/day temperature) and 20/30°C, respectively. In contrast, the highest germination rate was observed for the 0Mpa of the water potential treatment. Additionally, base temperature (T_base) and base water potential (W_base) were lower for M (7.7°C, -1.11Mpa at 10/20°C, and -1.07Mpa at 20/30°C) than for P (9.4°C, -0.92Mpa at 10/20°C, and -0.52Mpa at 20/30°C). These different germination strategies of M and P seeds with respect to temperature and water potential increased overall plant propagation. These results indicate that tropical and subtropical regions water potentials beyond -0.50Mpa (10/20°C) or -1.00Mpa (20/30°C) face a potential risk of C. pauciflorus invasion.