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Tafoni are a type of cavernous weathering features widespread in different climate zones around the world, but their origin has not been fully understood. Little attention was paid on tafoni in conglomerates. Danxiashan UNESCO Global Geopark, located within the subtropic humid region of South China, has a landscape of large tafoni that occur on cliffs of red conglomerates. Both the Dinosaur Rock and Pagoda Peak of the geopark were selected to investigate the formation mechanisms of tafoni in conglomerates. During the field investigation, the size, rock hardness, and the external and internal meteorology of tafoni were measured and tested. The texture and composition of rock samples were observed, and the ion chromatography experiments were performed as well. Results show that tafoni have well ellipsoidal openings. Clasts of the conglomerates are largely sub-rounded and poorly sorted, and the cement is dominantly composed of calcite and iron oxide. The hardness of the lips is almost equal to that of the columns, and both are slightly higher than the backwalls. Compared with the external intense environmental changes, the interior of the tafoni is characterized by smaller temperature and relative humidity ranges and windless condition. Therefore, the porous and permeable conglomerates provide favorable lithology for tafoni development, and the micro-environment within the caverns is conducive to improving water utilization efficiency and enhancing salt weathering. The salts mainly consist of sulfates and nitrates, which might be derived from frequent raining, water evaporation and red beds as well. Consequently, tafoni are the result of the synergistic effects by multiple factors, rather than a single mechanism.

COVID-19 should not be the world's last public health disaster, so there is an urgent need to learn from COVID-19 to prepare better for the next public health disaster. This study aims to understand the factors that make people wear a face mask at the beginning of an outbreak of public health disaster. Semi-structured interviews were conducted during April 2020 in China, one month after the COVID-19 was declared a pandemic. The respondents were members of the public living in China, covering two age groups: young adults and older adults. They were recruited using a convenient sample and snowball sampling strategy. The results were analysed using content analysis. Seventeen subjects were recruited, among which nine were young adults (average age = 26.4; SD = 10.5), and eight were older adults (average age = 60.4; SD = 12.1). This study found that environmental factors, personal factors, factors concerning wearing masks, specific circumstances, and development of the pandemic were the common factors considered by both young adults and older adults. This study should help the authority formulate prevention policies better to reduce the risk of an outbreak if there is a new virus outbreak in the future, unfortunately., Graphical abstract Image 1

Compared with root-associated habitats, little is known about the role of microbiota inside other rice organs, especially the rhizome of perennial wild rice, and this information may be of importance for agriculture. Oryza longistaminata is perennial wild rice with various agronomically valuable traits, including large biomass on poor soils, high nitrogen use efficiency, and resistance to insect pests and disease. Here, we compared the endophytic bacterial and archaeal communities and network structures of the rhizome to other compartments of O. longistaminata using 16S rRNA gene sequencing. Diverse microbiota and significant variation in community structure were identified among different compartments of O. longistaminata. The rhizome microbial community showed low taxonomic and phylogenetic diversity as well as the lowest network complexity among four compartments. Rhizomes exhibited less phylogenetic clustering than roots and leaves, but similar phylogenetic clustering with stems. Streptococcus, Bacillus, and Methylobacteriaceae were the major genera in the rhizome. ASVs belonging to the Enhydrobacter, YS2, and Roseburia are specifically present in the rhizome. The relative abundance of Methylobacteriaceae in the rhizome and stem was significantly higher than that in leaf and root. Noteworthy type II methanotrophs were observed across all compartments, including the dominant Methylobacteriaceae, which potentially benefits the host by facilitating CH4-dependent N2 fixation under nitrogen nutrient-poor conditions. Our data offers a robust knowledge of host and microbiome interactions across various compartments and lends guidelines to the investigation of adaptation mechanisms of O. longistaminata in nutrient-poor environments for biofertilizer development in agriculture.

Objective The purpose of this study was to describe the population pharmacokinetics (PK) of tacrolimus (TAC) in 52 Chinese pediatric patients early after liver transplantation. Methods Details of drug dose, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data from the first day after surgery. A total of 488 concentration data were obtained and analyzed by a nonlinear mixed-effect modeling (NONMEM) method. A number of demographic and clinical variables were tested for their influence on TAC PK parameters. Results The PK of TAC were best described by a one-compartment model with first-order absorption and elimination. Apparent clearance (CL/F) and apparent volumes of distribution (V/F) in final population model were 5.72 L/h and 131 L, respectively. The absorption rate constant (Ka) was fixed in 4.48 h-1. The inter-individual variabilities in CL/F and V/F were 13.5% and 78.1%. In the final analysis performed in all 52 patients, the post-operation day (POD) and alanine aminotransferase (ALT) influenced TAC CL/F and V/F, and total protein (TP) was the only covariate retained on V/F. Conclusion A population PK model of TAC was developed in Chinese pediatric patients early after liver transplantation. It identified significant relationships between the PK of TAC and the characteristics of the patients. POD, ALT, and TP were identified as the main factors influencing the PK of TAC. The developed model could be useful to optimize individual pediatric TAC dosing regimen in routine clinical practice.

A dual-frequency satellite antenna is designed for the applications of global navigation satellite systems (GNSSs). The proposed antenna consists of a square radiation patch with a double-arrow array loaded, which is formed by introducing anchor-like arrows as resonators at four corners respectively. The double-arrow array, with the adjustable lengths of its internal and external branches, is loaded on the patch to control the radiation properties flexibly. The simulation results show that the operation frequencies covering B3 and L1 bands, i.e., at 1.268 GHz and 1.575 GHz, can be acquired. In addition, in order to explain the relationship between the resonances and structure dimensions, the parametric studies based on the gap size of the anchor-like arrows and the length of the resonator are also discussed. It is clear that the demand of GNSS applications could be satisfied, according to the surface currents and antenna gains at different frequencies demonstrated and analyzed in detail.

The adsorption equilibria of pure linear alkanes, involving n-pentane, n-hexane, and n-heptane in pillared layered materials are simulated using configurational-bias Monte Carlo (CBMC) techniques in grand canonical ensemble. In the CBMC simulation, pillared layered pores are modelled by a uniform distribution of pillars between two solid layered walls with a given size of interlayer gallery. And a grid model is employed here to calculate the interaction between fluid molecules and two layered boards. Our simulation results are in a good agreement with the reported experimental data on the adsorption of nitrogen at 77 K, indicating that the grid model used in this work is effective. Then, a series of CBMC simulations of the adsorption isotherms of pure n-pentane, n-hexane, and n-heptane in pillared layered pores with three different porosities ψ = 0.98, 0.94 and 0.87, and three pore widths H = 1.02, 1.70 and 2.38 nm at temperature T = 300 K has been carried out.

Nowadays, since there are many artificial intelligence techniques introduced into our daily life, which brings us much convenience, its a real hope that our transportation can be improved by artificial intelligence. In this article, a smart car with the detecting and following ability is introduced. The whole system is composed of the road track signal device; the electromagnetic sensor; the power source manage device; the engine drive device and the parking position detecting device. By using the PID, Bang-Bang and fuzz control methods, the smart car can collect the signal automatically and control the car moving effectively. When there are specially designed roads with electromagnetic field, our smart cars can automatically drive themselves.

No one can deny the significance of wireless communication in our life, but there is always noise that can lead to some mistakes in transmitting signal. Facing the noise, we should realize that we cannot eliminate completely. Therefore, we should estimate the signal-to-noise ratio so that we can balance the Bit Error Rate and the power, which can save more energy. Here is a simple way to estimate the signal-to-noise ratio based on Bernoulli's Law of Large Numbers.

A series of composite materials have been prepared through assembly of two natural polymers, attapulgite and silk fibroin, to adjust the slow release performances of diclofenac molecules, a type of non-steroidal drugs. The assembled composite materials have a core-shell structure, with attapulgite composing the core and silk fibroin composing the shell. It has been found that the formation of the core-shell structure can reduce the release rate of diclofenac to a higher extent. When a small amount of ammonium molybdate was introduced into the composite material's silk fibroin layer, different release performances of drug molecules could be produced. In particular, the release performances of drug molecules contained in the assembled composite materials could be adjusted through UV irradiation. Characterization of the assembled composite materials and mechanism researches of release behaviors of the diclofenac molecules have been conducted by PXRD, SEM, IR, elemental analysis, and zeta potential, etc., in ...

This study investigated the solution of the rigidity and structural vibration for system of linear guideway type based on ANSYS workbench. By comparing the results derived from the simulation of the model and the corresponding theoretical results, the validity of the theoretical solution can be verified. The analysis includes the system rigidity and the natural vibration frequency in the direction of vertical slider (Vertical), rolling (Rolling) and swing (Pitching), the structural vibration frequency for system of linear guideway type is carried out, the model is built according the true dimensions, what is more, the rollers are not necessary replaced by springs, because there is not so much difficulties by using ANSYS workbench and more accurate results can be obtained in this way. Two different types of simulation are carried out, and the simulation results show that different geometric sizes of slider, which mean different numbers of rollers, will change the resonance frequencies and mode shapes, and more rollers can enhance the stiffness of the LGT model, then reduce the possibility of resonance happening.

This paper presents new machining technology of micro-EDM with lower working voltage in RC pulse power source. How to control the discharging energy of one pulse supplied by RC power is crucial to the technology of micro-EDM. The process of discharging has been studied, then the feasibility of machining with lower working voltage has been put forward, in order to reduce the discharge energy of one pulse effectively. On the basis of a great deal of experiments, the effect of working voltage on surface quality is studied, also the effect of working voltage on machining efficiency has been found out and been analyzed theoretically. The result shows that lower working voltage can reduce the working energy observably, and then improve the machining surface quality attended by reducing of machining efficiency. However, there is a good machining effect when the working voltage is about 15~20V. Considering working efficiency, a new technology of block electro-discharge grinding (BEDG) with lower working voltage has been applied. As shown by the experimental result with the technology, the minimum diameter of micro-shaft reaches 32m. Moreover, the micro-shaft has very high surface quality of Ra 0.1252m and its coaxial diameter error is controlled within 0.152m.

Phenoxymethylpenicillin (PMP) has been reversibly intercalated into a layered double hydroxide, and the resulting composite exhibits effective anti-bacterial activity. Powder X-ray diffraction studies indicate that the PMP molecules are interdigitated between the inorganic layers, and under mild acidic media, the molecules are released gradually. Therefore a sustained-release anti-bacterial medication is envisioned on the basis of this inorganic–drug composite. Copyright © 2005 Society of Chemical Industry

Hollow layered MoO 3 microspheres were obtained by the adsorption of 12-molybdodiphosphate onto the surface of a spherical anion exchange resin followed by calcination of the resulting 12-molybdodiphosphate-resin composite. The conductivity of the sphere shell can be improved by intercalating polyaniline between layers of MoO 3 particles in the sphere shell.

A novel composite material, α-Zr(HPO4)2·1.5Lysine:0.06Eu3+ (designated ZLE), has been prepared through intercalation of L-lysine (Lys) molecules and Eu3+ ions into between the layers of α-Zr(HPO4)2 (α-ZrP). It is proposed that the ZLE material contains Eu complexes lying between adjacent layers of Lys molecules which are attached on the inner surface of α-ZrP, and the Eu3+ ions are coordinated by carboxyl groups of Lys molecules. The ZLE composite in combination with Al(i-Bu)3 and glycerin has been used as a catalyst for the copolymerization of propylene oxide (PO) and CO2, and the catalytic system exhibits performance superior to the previously reported Y(P204)3-Al(i-Bu)3-glycerin system.

A thermophilic new strain of Methanothermobacter marburgensis DX01, with a different morphology from M. thermautotrophicus delta H, was isolated from a hot spring in China. To provide further molecular evidence to identify the methanogen M. marburgensis DX01, polymerase chain reaction melting profile (PCR MP) technique and protein fingerprint profiling were performed. Both DNA and protein fingerprint profiles showed significant differences between M. marburgensis DX01 and M. thermautotrophicus delta H. In addition, five interesting DNA fragments obtained from PCR MP of the DX01 strain were excised and sequenced. We found that all five DNA fragments were unique to M. marburgensis DX01. Expression of induced proteins in M. marburgensis DX01 was analyzed by protein fingerprint profiling and a protein that was more highly expressed at 70°C was excised and identified by N-terminal amino acid sequencing. We found that the up-regulated protein was Methyl-coenzyme M reductase І, which was 97.6% amino acid sequence identity with that of M. thermautotrophicus delta H. These studies may provide clues for a better understanding of the new isolate of thermophilic M. marburgensis. Key words: Methanothermobacter, polymerase chain reaction (PCR) melting profile, protein fingerprint profile analyses.

This paper analyzed the food production by the households in the counties with high population (Mizhi County) and low population (Wuqi County) in North Shaanxi, and studied the food security and its affecting factors in the two counties by using minimum cropland area per capita and Cobb-Douglass production function methods. The results demonstrated that the food production in low population county could meet the basic standard of food security, while that in high population county could not. Cultivated area and investment in agricultural technology were the major factors affecting food security; labor force, labor quality, and grain subsidy also had positive effects on food production. The current technology and labor quality did not reach their potential for food production. This region needed to increase grain production area to reach the minimum standard of 0.14 bm2 per capita, put much stress on labor force training, and formulate appropriate following policies for 'Grain for Green' to realize the food security strategy.

Economic and ecological methods were applied to investigate the ecological cost of grain production in the gully area of Loess Plateau. In the study area in 2008, the ecological loss due to grain production was 7.2% of the total crop output, and the ecological cost reached 2.42 yuan x kg(-1) for wheat and 2.12 yuan x kg(-1) for corn. However, the per unit sales were 1.70 yuan x kg(-1) for wheat and 1.28 yuan x kg(-1) for corn. The combination of high production cost and low income affected the sustainable development of local ecological economy. The analysis of grey relationships among various factors affecting the ecological cost of grain production indicated that yield, sown area, and agricultural mechanical cost were the important factors affecting the ecological cost of grain production, while chemical fertilizer cost and organic fertilizer cost had less impact on the ecological cost of grain production. Under current production conditions, the ecological cost of grain production in the area could be reduced by raising the level of scientific and technological inputs, expanding the scale of family agricultural production, and improving the grain yield.

The cyc1-512 mutant was previously shown to contain a 38-bp deletion, 8 nucleotides upstream from the major wild-type poly(A) site, in the CYC1 gene, which encodes iso-1-cytochrome c of the yeast Saccharomyces cerevisiae. This 38-bp deletion caused a 90% reduction in the CYC1 transcripts, which were heterogeneous in size, aberrantly long, and presumably labile (K. S. Zaret and F. Sherman, Cell 28:563-573, 1982). Site-directed mutagenesis in and adjacent to the 38-bp region was used to identify signals involved in the formation and positioning of CYC1 mRNA 3' ends. In addition, combinations of various putative 3' end-forming signals were introduced by in vitro mutagenesis into the 3' region of the cyc1-512 mutant. The combined results from both studies suggest that 3' end formation in yeast cells involves signals having the following three distinct but integrated elements acting in concert: (i) the upstream element, including sequences TATATA, TAG ... TATGTA, and TTTTTATA, which function by enhancing the efficiency of downstream elements; (ii) downstream elements, such as TTAAGAAC and AAGAA, which position the poly(A) site; and (iii) the actual site of polyadenylation, which often occurs after cytidine residues that are 3' to the so-called downstream element. While the upstream element is required for efficient 3' end formation, alterations of the downstream element and poly(A) sites generally do not affect the efficiency of 3' end formation but appear to alter the positions of poly(A) sites. In addition, we have better defined the upstream elements by examining various derivatives of TATATA and TAG ... TATGTA, and we have examined the spatial requirements of the three elements by systematically introducing or deleting upstream and downstream elements and cytidine poly(A) sites.

The cyc1-512 mutant of the yeast Saccharomyces cerevisiae contains a 38 bp deletion in the 3' untranslated region of the CYC1 gene, resulting in CYC1 mRNAs that are elongated, presumably labile, and reduced to 10% of the normal level. Analysis with S1 nuclease and a novel PCR procedure revealed that the low amount of cyc1-512 mRNA contained many discrete 3' termini at certain sites, ranging from the wild-type position to over 2000 nucleotides (nt) downstream. The cyc1-512 mRNA deficiency was completely or almost completely restored in eight intragenic revertants that contained six different single and multiple base-pair changes within a 300 bp region downstream from the translation terminator codon. Two of the six different reversions formed the sequence TAG...TATGTA, whereas the other four reversions created the sequences TATATA or TACATA. The positions of these revertant sequences varied, even though they caused an increased use of specific major downstream mRNA 3' endpoints, apparently identical to those seen in the cyc1-512 mRNA. However, several revertants contained minor end points not corresponding to any of the cyc1-512 mRNAs. The capacity of these three signals to form 3' ends was confirmed with sequences constructed by site-directed mutagenesis. We therefore suggest that the production of 3' termini of yeast mRNA may involve at least two functionally distinct elements working in concert. One type of element determines the sites of preferred 3' mRNA termini, as represented by the cyc1-512 termini. The second type of element, which includes TAG...TATGTA and TATATA motifs, operates at a distance to enhance the use of the downstream 3' preferred sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional TATA elements in the 5' untranslated region of the CYC1 gene in the yeast Saccharomyces cerevisiae have been defined by transcriptional analysis of site-directed mutations. Five sites previously suggested to contain functional TATA elements were altered individually and in all possible combinations. The results indicated that only two elements are required for transcription at the normal level and the normal start sites. The two functional TATA elements are located at sites -178 and -123, where the A of the ATG start codon is assigned nucleotide position +1. They direct initiation within windows encompassing -70 to -46 and -46 to -28, respectively. Only when both of the upstream TATA sites were rendered nonfunctional were the third and fourth downstream TATA-like sequences activated, as indicated by the presence of low levels of transcription starting at -28. The two upstream functional TATA elements differed in sequence. The sequence of the most 5' one at site 1, denoted beta-type, was ATATATATAT, whereas that of the second one at site 2, denoted alpha-type, was TATATAAAA. The following rearrangements of the beta-type and alpha-type elements at two sites (1 and 2) were examined: site1 beta-site2 alpha; site 1 alpha-site 2 beta; site1 alpha-site2 alpha; and site1 beta-site2 beta. When different types were at different sites (site1 beta-site2 alpha and site1 alpha-site2 beta), both were used equally. In contrast, when the same type was present at both sites (site1 alpha-site2 alpha and site1 beta-site2 beta), only the upstream element was used. We suggest that the two TATA elements are recognized by different factors of the transcription apparatus.