Determination of the coefficient of thermal expansion of ultra-low-expansion glass using an ultrasonic immersion testing method.

The coefficient of thermal expansion (CTE) of ultra-low-expansion (ULE) glass is critical to the development of precision optical systems. Herein, an ultrasonic immersion pulse-reflection method is proposed to characterize the CTE of ULE glass. The ultrasonic longitudinal wave velocity of ULE-glass samples with significantly different CTE values was measured using a correlation algorithm combined with moving-average filtering, which can achieve 0.2 m/s precision with a contribution to the ultrasonic CTE measurement uncertainty of 0.47 ppb/°C. Furthermore, the established ultrasonic CTE measurement model predicted the 5°C-35°C mean CTE with a root-mean-square error of 0.9 ppb/°C. Notably, a complete uncertainty analysis methodology was established in this paper, which can provide directional guidance for the subsequent development of higher-performance measurement devices and the improvement of relevant signal processing procedures.

Broadband devices for a polarization converter based on optical metasurfaces.

Devices employed for optical polarization conversion are widely used in the areas of optical focusing, optical imaging, and microscopy. To circumvent the problems of traditional optical polarization conversion devices, such as a narrow bandwidth, bulky size, and integration difficulties, a linear-radial polarization converter (LRPC) method based on optical metasurfaces is proposed. For a visible wavelength, i.e., λ=632.8nm, an all-dielectric half-wave plate and a LRPC with a size of 40λ (25.312 µm) are designed. The simulated results demonstrate that the LRPC creates a radially polarized wave from a linearly polarized wave in the wavelength range of 620-680 nm. In addition, a cylindrical vectorial wave with different polarizations can be generated via an adjustment of the polarization direction of the incident wave. These types of polarization converters have the important advantage of high transmittance, while also being ultra-thin and easy to integrate. They are expected to be suitable for miniaturized and integrated optical devices.

Terahertz sensor based on a three-dimensional double I-type metamaterial integrated microfluidic channel.

Terahertz metamaterial sensors have received extensive attention in biosensing applications. However, sensitivity toward terahertz frequencies emitted by liquid samples remains challenging because of the strong absorption of terahertz waves by water. Here, we present a highly sensitive terahertz sensor based on a three-dimensional double I-type metamaterial integrated microfluidic channel. The designed sensor produces an inductive-capacitive (LC) resonance with a high quality factor of approximately 72, while demonstrating a maximum sensitivity of 832 GHz/RIU. Furthermore, we analyzed the relationship between the resonance frequency and ethanol concentration. These findings would promote the application of terahertz technology in label-free and rapid biomedical sensing as well as substance detection.

The Phytophthora infestans AVR2 Effector Escapes R2 Recognition Through Effector Disordering.

Intrinsic disorder is a common structural characteristic of proteins and a central player in the biochemical processes of species. However, the role of intrinsic disorder in the evolution of plant-pathogen interactions is rarely investigated. Here, we explored the role of intrinsic disorder in the development of the pathogenicity in the RXLR AVR2 effector of Phytophthora infestans. We found AVR2 exhibited high nucleotide diversity generated by point mutation, early-termination, altered start codon, deletion/insertion, and intragenic recombination and is predicted to be an intrinsically disordered protein. AVR2 amino acid sequences conferring a virulent phenotype had a higher disorder tendency in both the N- and C-terminal regions compared with sequences conferring an avirulent phenotype. In addition, we also found virulent AVR2 mutants gained one or two short linear interaction motifs, the critical components of disordered proteins required for protein-protein interactions. Furthermore, virulent AVR2 mutants were predicted to be unstable and have a short protein half-life. Taken together, these results support the notion that intrinsic disorder is important for the effector function of pathogens and demonstrate that SLiM-mediated protein-protein interaction in the C-terminal effector domain might contribute greatly to the evasion of resistance-protein detection in P. infestans.

Generation of subdiffraction longitudinal bifoci by shaping a radially polarized wave.

Lenses with two or more foci along the longitudinal direction exhibit immense potential in several optical applications. In this study, we propose an approach for generating subdiffraction longitudinal bifoci by binary-phase bifocal super-oscillatory lenses (SOLs), which are realized by simple AND operation between two single-foci SOLs with different focal lengths. Three bifocal SOLs with radiusRlens=70λ are designed at an operating wavelength of λ=118.8µm. Simulation results demonstrate that the minimum full width at half maximum (FWHM) is 0.397λ, and the maximum FWHM is 0.449λ, which is still smaller than the Abbe diffraction limit of 0.510λ, while all the sidelobe ratios are small (<15.1%). By properly choosing the focal length of the single-foci SOLs in the design process, the distance between the two foci can be easily controlled. Significantly, the generated bifoci with relatively uniform intensity contain a strong longitudinal electric field, which indicates their excellent prospects in optical imaging, particle acceleration, and other optical applications. In addition, the proposed bifoci-SOLs are based on the binary phase modulation, which facilitates easy fabrication compared with other approaches. These outstanding properties indicate the wide application prospects of bifocal SOLs.

Cross-resistance of the pathogenic fungus Alternaria alternata to fungicides with different modes of action.

BACKGROUND: Cross-resistance, a phenomenon that a pathogen resists to one antimicrobial compound also resists to one or several other compounds, is one of major threats to human health and sustainable food production. It usually occurs among antimicrobial compounds sharing the mode of action. In this study, we determined the sensitivity profiles of Alternaria alternata, a fungal pathogen which can cause diseases in many crops to two fungicides (mancozeb and difenoconazole) with different mode of action using a large number of isolates (234) collected from seven potato fields across China. RESULTS: We found that pathogens could also develop cross resistance to fungicides with different modes of action as indicated by a strong positive correlation between mancozeb and difenoconazole tolerances to A. alternata. We also found a positive association between mancozeb tolerance and aggressiveness of A. alternata, suggesting no fitness penalty of developing mancozeb resistance in the pathogen and hypothesize that mechanisms such as antimicrobial compound efflux and detoxification that limit intercellular accumulation of natural/synthetic chemicals in pathogens might account for the cross-resistance and the positive association between pathogen aggressiveness and mancozeb tolerance. CONCLUSIONS: The detection of cross-resistance among different classes of fungicides suggests that the mode of action alone may not be an adequate sole criterion to determine what components to use in the mixture and/or rotation of fungicides in agricultural and medical sects. Similarly, the observation of a positive association between the pathogen's aggressiveness and tolerance to mancozeb suggests that intensive application of site non-specific fungicides might simultaneously lead to reduced fungicide resistance and enhanced ability to cause diseases in pathogen populations, thereby posing a greater threat to agricultural production and human health. In this case, the use of evolutionary principles in closely monitoring populations and the use of appropriate fungicide applications are important for effective use of the fungicides and durable infectious disease management.

Trade-offs and evolution of thermal adaptation in the Irish potato famine pathogen Phytophthora infestans.

Temperature is one of the most important environmental parameters with crucial impacts on nearly all biological processes. Due to anthropogenic activity, average air temperatures are expected to increase by a few degrees in coming decades, accompanied by an increased occurrence of extreme temperature events. Such global trends are likely to have various major impacts on human society through their influence on natural ecosystems, food production and biotic interactions, including diseases. In this study, we used a combination of statistical genetics, experimental evolution and common garden experiments to investigate the evolutionary potential for thermal adaptation in the potato late blight pathogen, Phytophthora infestans, and infer its likely response to changing temperatures. We found a trade-off associated with thermal adaptation to heterogeneous environments in P. infestans, with the degree of the trade-off peaking approximately at the pathogen's optimum growth temperature. A genetic trade-off in thermal adaptation was also evidenced by the negative association between a strain's growth rate and its thermal range for growth, and warm climates selecting for a low pathogen growth rate. We also found a mirror effect of phenotypic plasticity and genetic adaptation on growth rate. At below the optimum, phenotypic plasticity enhances pathogen's growth rate but nature selects for slower growing genotypes when temperature increases. At above the optimum, phenotypic plasticity reduces pathogen's growth rate but natural selection favours for faster growing genotypes when temperature increases further. We conclude from these findings that the growth rate of P. infestans will only be marginally affected by global warming.

[Research on the Method of Improving Terahertz Frequency Resolution Based on Empirical Mode Decomposition].

Terahertz frequency resolution is an important factor affecting substance identification, but the presence of the device reflection within the terahertz time domain spectroscopy systems, causes the presence of a plurality of reflection peaks in the reference and measurement signals with low frequency resolution, because of the length truncation of time domain signal. In order to remove the influence of the reflection peak, this paper proposes a method based on empirical mode decomposition to remove the time domain reflection peak, to improve the terahertz frequency resolution. The time domain reflection peaks are positioned by correlation with the real terahertz peak, calculating the reflection peak upper and lower envelope and an average, obtaining intrinsic mode functions, and alternating reflection peaks with intrinsic mode functions, the effective length of the time domain signal is increased to improve the terahertz frequency resolution. Water vapor in the air terahertz transmission spectroscopy results show that this method can self adaptively remove a plurality of reflection peaks and has good repairing effect on the terahertz time-domain signal; the frequency resolution is increased by 12 times; and the useful information of absorption spectrum is not lost; the absorption peak position and the number is consistent with real spectrum; the terahertz spectrum ability to identify is well preserved.

[Absorption Characteristics and Simulation of LLM-105 in the Terahertz Range].

2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), a novel explosive with high energy and low sensibility. In order to study the molecular structure characteristics of the explosive, the absorption spectra of LLM-105 in the frequency range of 0.2-2.4 THz were detected by terahertz time-domain spectroscopy (THz-TDS). The results showed that a number of characteristic absorption peaks with different intensity located at 1.27, 1.59, 2.00, 2.08, 2.20, 2.29 THz. The article also simulated the absorption spectra of LLM-105 molecular crystal within 0.2-2.5 THz region by using Materials Studio 6.0 software based on density functional theory (DFT), and the simulated results agreed well with the experimental data except for the peak at 2.29 THz, which verified theoretically the accuracy of the experimental data. In addition, the vibrational modes of the characteristic peaks in the experimental absorption spectra were analyzed and identified, the results showed that the forming of the characteristic absorption peaks and the molecular vibration were closely related, which further provided important laboratory and technology support for the study of the transformation of molecule structure of LLM-105. There was no simulated frequency agreed with the experimental absorption peak at 2.29 THz, which may be caused by the vibration of the crystal lattice or other reasons.

[Experimental Conditions of Laser Induced Breakdown Spectroscopy of Metal Elements in Cement].

Laser induced breakdown spectroscopy (LIBS) is a widely used material element detection technology. Because of its detection result is affected by many factors, and therefore, analysing and comparising the different experimental conditions have important significance for LIBS. Experimental sample produced by Beichuan County, Sichuan Province, China, which is ordinary Portland cement P. O42.5, using eight-channel fiber optic spectrometer AvaSpec-2048-USB2-RM, delay trigger DG645 for LIBS testing. Several metallic elements as Mg, Al, Na, K, which affect cement's technical indicators were analyzed. Mainly compares the effect of laser frequency, the same point measurement times on different metal element spectral signal intensity, the optimum experimental parameters under the condition of this experiment: 10 Hz was the best laser frequency. When laser frequency is 10 Hz, the spectrum intensity of elements Mg, Al, Na, K were increased by 67.66%, 47.88%, 84.59%, 43.36% than 8 Hz. Because the tablet samples in place, the surface will have a small amount of oxidation and deliquescence, in order to measure 10 times for an average income results were recorded under the condition, with third, four records of results for the best.

[Acidity and temperature effect on the fluorescence characteristics of hydraulic oils and lubricants].

By analyzing HyJet V phosphate ester hydraulic oil environmental impacts (oil, etc.) and confounding factors (pH, temperature, etc.), the feasibility was studied for the fluorescence detection of aircraft hydraulic oil leaks. By using the fluorescence spectrophotometer at various acidities and temperatures, the fluorescence properties of HyJet V phosphate ester hydraulic oil, Jet Oil II lubricant and 2197 lubricant were gained. The experimental results are shown as following: The fluorescence peaks of HyJet V phosphate ester hydraulic oil, Jet Oil II lubricant and 2197 lubricant are at 362, 405 and 456 nm, respectively. The impact of temperature on HyJet V phosphate ester hydraulic oil is less effective; Jet Oil II lubricant and 2197 lubricant fluorescence intensity decreases with increasing temperature. When acidity increases, the fluorescence peak of HyJet V phosphate ester hydraulic oil gradient shifts from 370 to 362 nm, and the fluorescence intensity decreases; the fluorescence peak of Jet Oil II lubricant is always 405 nm, while the fluorescence intensity decreases; the fluorescence peak of 2197 lubricant at 456 nm red shifts to 523 nm, and double fluorescence peaks appeare. The results are shown as following: under the influence of the environment and interference factors, the fluorescence characteristics of HyJet V phosphate ester hydraulic oil remain unchanged, and distinguish from Jet Oil II lubricant and 2197 lubricant. Therefore, the experiments indicate that the detection of HyJet V phosphate ester hydraulic oil leak is feasible by using fluorescence method.

Identification and low-frequency vibrational analysis of three free anthraquinones via terahertz spectroscopy.

In this study, terahertz time-domain spectroscopy (THz-TDS) was used to obtain the terahertz absorption spectra of three free anthraquinones (Chrysophanol, Emodin, Physcion) in the frequency range of 0.2-4.3 THz. The results show that terahertz spectroscopy is an effective detecting such compounds. Meanwhile, the theoretical spectrum using density functional theory calculations agrees well with the experimental spectrum. A modal decoupling method was used to identify each low-frequency vibrational mode and determine the average contribution of different atoms and groups. Modal decoupling provides a better understanding of molecules' mixed vibrational modes and enables quantifying the atoms' vibrational contributions. Results show that the substituent group facilitates the transition between the fundamental vibrational modes; subsequently, the substituent group shifts the vibrational centre of gravity of the three molecules and affects the vibrational contribution of hydrogen bonds. Furthermore, insignificant Emodin absorption is related to the nearly symmetrical structure formed by the substituents. The feasibility of terahertz analysis of differential molecular structures has also been confirmed.

Low-dose decitabine for refractory thrombocytopenia following allogeneic hematopoietic stem cell transplantation in children: A pilot study.

Refractory thrombocytopenia is a critical complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT), which is not sensitive to conventional treatment and often leads to lower overall survival and disease-free survival. Previous studies have showed the efficacy and safety of low-dose decitabine for adults' refractory prolonged isolated thrombocytopenia in hematologic malignancy after allo-HSCT. However, clinical data on pediatric patients or non-hematologic malignancies are lacking. Herein, we evaluated the safety and efficacy of low-dose decitabine in nine children with persistent thrombocytopenia after HSCT. Patients received decitabine at 3.5 mg/m2, 5 mg/m2 or 10 mg/m2 respectively for three to five consecutive days according to underlying diseases and hyperplastic state of bone marrow. Six patients reached sustained platelets count more than 100 × 109/L, two patients achieved platelet transfusion independence. The total response rate was 88.8 % (8/9). One patient died from severe infection because of persistent agranulocytosis longer than 3 weeks. In conclusion, the present study supports the safety and efficacy of low-dose decitabine for treatment of refractory thrombocytopenia after allogeneic HSCT in children.

[Effect of temperature and pH on the fluorescence characteristic of oily waste water].

The present study was about the effect of temperature (5-55 degrees C) and pH (3-12) value on the fluorescence characteristic of oily waste water from the export of China Petroleum & Chemical Oil Refinery. It was found that temperature only affects the fluorescence intensity but not the site of fluorescence peaks. The fluorescence peaks shift right that from 413 to 426.5 nm when the oily waste water is acid. And along with the enhancing of the acidity the fluorescence intensity ascended. The fluorescence intensity decreased with alkaline enhancing but the site of fluorescence peaks remained unchanged at 398 nm. Temperature and pH value were the two important impact factors on the fluorescence characteristic of oily waste water. If desired it needs correction and compensation on temperature and pH value. That's expected to improve the detection accuracy of oil class and content.

[Feasibility of using laser-induced fluorescence to detect directly polycyclic aromatic hydrocarbons in soil].

Abstract In the present paper, a technique of laser-induced fluorescence(LIF)for direct assay of polycyclic aromatic hydrocarbons(PAH) in soil was put forward. The research objective of this article is anthracene. The possibility of using LIF spectra to detect directly anthracene in soil was studied. Anthracene was detected in soil by AvaSpec-3648 Fiber Optic Spectrometer of thermoelectric refrigeration. The authors drew a conclusion that in the range of certain anthracene concentration(0.000 005-0.001 g x g(-1)), the intensity of LIF fluorescence is linear with anthracene concentration in soil, with a regression coefficient of 0. 929. This showed that direct assay of anthracene in soil was feasible by laser-induced fluorescence. The study is important to developing a new analytical technique of quantitative fluorescence detector which can be applied to the analysis of PAH in soil without pretreatment, and is significant to realization of real-time, in-line, in-situ measurement of PAH in soil.

MicroRNA-221 regulates cell activity and apoptosis in acute lymphoblastic leukemia via regulating PTEN.

T cell acute lymphoblastic leukemia (T-ALL), an aggressive and heterogeneous malignancy originating from T cell precursors (thymocytes), accounts for ~15% of all ALL cases in children and for ~25% in adults. The present study aimed to investigate the role of microRNA-221 (miR-221) in the regulation of cell viability and apoptosis of human T-ALL cells and its related regulatory mechanisms. To perform this investigation, miR-221 was upregulated or knocked down in human T-ALL cells (Jurkat cells) using miR-221 mimic or inhibitor, respectively. Then, cell viability was determined using a 3-(4,5-dimethylthiahiazol-2-y1)-2,5-diphenytetrazolium bromide assay, cell invasion and migration were analyzed via Transwell assays, and cell apoptosis was detected using flow cytometry. It was found that transfection with a miR-221 inhibitor significantly inhibited Jurkat cell viability, migration and invasion, and induced Jurkat cell apoptosis. Whereas, transfection with the miR-221 mimic resulted in the opposite effects. Besides, the results showed that phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was a target of miR-221. Moreover, it was observed that the effects of the miR-221 inhibitor on Jurkat cell viability, migration and invasion, and cell apoptosis were significantly eliminated by PTEN-small interfering RNA. In addition, it was shown that the phosphatidylinositol 3-kinase/AKT pathway was involved in the effect of miR-221 on Jurkat cells. In conclusion, the data indicated that miR-221 existed as an oncogene in T-ALL, and its downregulation could inhibit the development of ALL by targeting PTEN. Therefore, miR-221 may be a novel potential therapeutic target for ALL.

Increasing temperature elevates the variation and spatial differentiation of pesticide tolerance in a plant pathogen.

Climate change and pesticide resistance are two of the most imminent challenges human society is facing today. Knowledge of how the evolution of pesticide resistance may be affected by climate change such as increasing air temperature on the planet is important for agricultural production and ecological sustainability in the future but is lack in scientific literatures reported from empirical research. Here, we used the azoxystrobin-Phytophthora infestans interaction in agricultural systems to investigate the contributions of environmental temperature to the evolution of pesticide resistance and infer the impacts of global warming on pesticide efficacy and future agricultural production and ecological sustainability. We achieved this by comparing azoxystrobin sensitivity of 180 P. infestans isolates sampled from nine geographic locations in China under five temperature schemes ranging from 13 to 25°C. We found that local air temperature contributed greatly to the difference of azoxystrobin tolerance among geographic populations of the pathogen. Both among-population and within-population variations in azoxystrobin tolerance increased as experimental temperatures increased. We also found that isolates with higher azoxystrobin tolerance adapted to a broader thermal niche. These results suggest that global warming may enhance the risk of developing pesticide resistance in plant pathogens and highlight the increased challenges of administering pesticides for effective management of plant diseases to support agricultural production and ecological sustainability under future thermal conditions.

[The preliminary research on information redundance in fluorescence spectral data process].

This paper presented the problem of information redundance factor in spectral data analysis. Three-component mixtures fluorescence spectra data of anthracene, pyrene and phenanthrene, which were typical polycyclic aromatic hydrocarbons (PAHs), were investigated through principal component regression analysis and move windows wavelength selection in chemometrics. Theoretical analysis and experimental result demonstrated that there was information redundancy in fluorescence signal; the data which have been optimized by redundancy techniques could show more realistic information of the test samples quantitatively, and for the multi-component mixed system with spectral overlapped seriously, analysis with the data which have been optimized through redundancy techniques could improve the sensitivity and stability of the models.

[The quantitative analysis of polycomponent PAHs by netural network based on data synthese and principal].

The present paper used synthesized data from the experiment samples to replace partial basic experiments, and increased the training samples amount from 14 to 27. In principal component analysis (PCA), the dimensionality of multivariate data was reduced to n principal components and almost all data information was kept. The PCA reduced the network's input nodes from 60 to 3 to simplify the neural network's structure. Finally, back-propagation neural network was used to train and predict these samples. It had 27 training samples, the input layer had three nodes, the hidden layer had two nodes, and the output layer had two nodes. Its excitation function is variable learning rate method. The results show that the coefficient of recovery can reach 89.6-109.0. It has reached the expected purpose.

[Study on the fluorescent characteristic of tryptophan in the process of the waste water treatment].

Tryptophan is one kind of representative pollutants in waste water. The present paper focuses on the research on the relation between the consistence, pH, ionic strength and the fluorescent characteristic of tryptophan. The result shows that: (1) Tryptophan in the low consistence range (0.01-3 m x L(-1)) shows good linear relation, the correlation coefficient is up to 0.995 88, while the linear relation in the high consistence range (3-30 mg x L(-1)) is slightly worse and the correlation coefficient is only 0.942 24; (2) In the acidic condition, the relative fluorescence intensity of tryptophan strengthens while the pH arises, and when the pH is in the range (6.5, 7.5), the intensity is relatively steady, while when the pH reaches 12, it drops off; (3) With the enhancement of the ionic strength, the relative fluorescence intensity of tryptophan reduces to some extent, and when the nitrate ion reaches to a high consistence, the spectrogram shows EERS.